Academic literature on the topic 'PPV and NPV'
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Journal articles on the topic "PPV and NPV"
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Bruells, Christian S., Ashley J. Smuder, Lucy K. Reiss, et al. "Negative Pressure Ventilation and Positive Pressure Ventilation Promote Comparable Levels of Ventilator-induced Diaphragmatic Dysfunction in Rats." Anesthesiology 119, no. 3 (2013): 652–62. http://dx.doi.org/10.1097/aln.0b013e31829b3692.
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Abstract Background: Mechanical ventilation is a life-saving intervention for patients with respiratory failure. Unfortunately, a major complication associated with prolonged mechanical ventilation is ventilator-induced diaphragmatic atrophy and contractile dysfunction, termed ventilator-induced diaphragmatic dysfunction (VIDD). Emerging evidence suggests that positive pressure ventilation (PPV) promotes lung damage (ventilator-induced lung injury [VILI]), resulting in the release of signaling molecules that foster atrophic signaling in the diaphragm and the resultant VIDD. Although a recent report suggests that negative pressure ventilation (NPV) results in less VILI than PPV, it is unknown whether NPV can protect against VIDD. Therefore, the authors tested the hypothesis that compared with PPV, NPV will result in a lower level of VIDD. Methods: Adult rats were randomly assigned to one of three experimental groups (n = 8 each): (1) acutely anesthetized control (CON), (2) 12 h of PPV, and (3) 12 h of NPV. Dependent measures included indices of VILI, diaphragmatic muscle fiber cross-sectional area, diaphragm contractile properties, and the activity of key proteases in the diaphragm. Results: Our results reveal that no differences existed in the degree of VILI between PPV and NPV animals as evidenced by VILI histological scores (CON = 0.082 ± 0.001; PPV = 0.22 ± 0.04; NPV = 0.25 ± 0.02; mean ± SEM). Both PPV and NPV resulted in VIDD. Importantly, no differences existed between PPV and NPV animals in diaphragmatic fiber cross-sectional area, contractile properties, and the activation of proteases. Conclusion: These results demonstrate that NPV and PPV result in similar levels of VILI and that NPV and PPV promote comparable levels of VIDD in rats.
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Ben-Haim, Yakov, and Clifford C. Dacso. "Interpreting PPV and NPV of Diagnostic Tests with Uncertain Prevalence." Rambam Maimonides Medical Journal 15, no. 3 (2024): e0013. http://dx.doi.org/10.5041/rmmj.10527.
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Objective: Medical decision-making is often uncertain. The positive predictive value (PPV) and negative predictive value (NPV) are conditional probabilities characterizing diagnostic tests and assessing diagnostic interventions in clinical medicine and epidemiology. The PPV is the probability that a patient has a specified disease, given a positive test result for that disease. The NPV is the probability that a patient does not have the disease, given a negative test result for that disease. Both values depend on disease incidence or prevalence, which may be highly uncertain for unfamiliar diseases, epidemics, etc. Probability distributions for this uncertainty are usually unavailable. We develop a non-probabilistic method for interpreting PPV and NPV with uncertain prevalence. Methods: Uncertainty in PPV and NPV is managed with the non-probabilistic concept of robustness in info-gap theory. Robustness of PPV or NPV estimates is the greatest uncertainty (in prevalence) at which the estimate’s error is acceptable. Results: Four properties are demonstrated. Zeroing: best estimates of PPV or NPV have no robustness to uncertain prevalence; best estimates are unreliable for interpreting diagnostic tests. Trade-off: robustness increases as error increases; this trade-off identifies robustly reliable error in PPV or NPV. Preference reversal: sometimes sub-optimal PPV or NPV estimates are more robust to uncertain incidence or prevalence than optimal estimates, motivating reversal of preference from the putative optimum to the sub-optimal estimate. Trade-off between specificity and robustness to uncertainty: the robustness increases as test-specificity decreases. These four properties underlie the interpretation of PPV and NPV. Conclusions: The PPV and NPV assess diagnostic tests, but are sensitive to lack of knowledge that generates non-probabilistic uncertain prevalence and must be supplemented with robustness analysis. When uncertainties abound, as with unfamiliar diseases, assessing robustness is critical to avoiding erroneous decisions.
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Schnaiter, Johannes, Frank Roemer, Axel McKenna-Kuettner, et al. "Diagnostic Accuracy of an MRI Protocol of the Knee Accelerated Through Parallel Imaging in Correlation to Arthroscopy." RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren 190, no. 03 (2017): 265–72. http://dx.doi.org/10.1055/s-0043-119038.
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Purpose Parallel imaging allows for a considerable shortening of examination times. Limited data is available about the diagnostic accuracy of an accelerated knee MRI protocol based on parallel imaging evaluating all knee joint compartments in a large patient population compared to arthroscopy. Materials and Methods 162 consecutive patients with a knee MRI (1.5 T, Siemens Aera) and arthroscopy were included. The total MRI scan time was less than 9 minutes. Meniscus and cartilage injuries, cruciate ligament lesions, loose joint bodies and medial patellar plicae were evaluated. Sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV), as well as diagnostic accuracy were determined. Results For the medial meniscus, the values were: SE 97 %, SP 88 %, PPV 94 %, and NPV 94 %. For the lateral meniscus the values were: SE 77 %, SP 99 %, PPV 98 %, and NPV 89 %. For cartilage injuries the values were: SE 72 %, SP 80 %, PPV 86 %, and NPV 61 %. For the anterior cruciate ligament the values were: SE 90 %, SP 94 %, PPV 77 %, and NPV 98 %, while all values were 100 % for the posterior cruciate ligament. For loose bodies the values were: SE 48 %, SP 96 %, PPV 62 %, and NPV 93 %, and for the medial patellar plicae the values were: SE 57 %, SP 88 %, PPV 18 %, and NPV 98 %. Conclusion A knee MRI examination with parallel imaging and a scan time of less than 9 minutes delivers reliable results with high diagnostic accuracy. Key Points Citation Format
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Noll, Kyle, Israt Tasnim, Priscella Asman, et al. "NCOG-34. CORRESPONDENCE BETWEEN INTRAOPERATIVE GAMMA BAND ELECTROCORTICOGRAMS AND DIRECT ELECTRICAL STIMULATION ACROSS DIVERSE NAMING TASKS IN PATIENTS WITH LANGUAGE-ELOQUENT BRAIN TUMORS." Neuro-Oncology 26, Supplement_8 (2024): viii232. http://dx.doi.org/10.1093/neuonc/noae165.0916.
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Abstract BACKGROUND Few studies have examined concordance between intraoperative electrocorticography (ECoG) and direct electrical stimulation (DES) language mapping, especially across varied naming tasks. METHODS Twelve patients (Mdn age=59; 75% HGG) underwent awake craniotomy with ECoG and DES language mapping. Mapping utilized iPad stimulus presentation coupled to a 4x8 electrode array for both ECoG and DES. Time-frequency ECoG gamma band activity (Early and Late) was visualized for 3 naming paradigms (Object, Action, Auditory). Bipolar DES was also conducted for each task at each electrode pair. ECoG activations and DES hits were overlayed on preoperative MRI. DES hits represented ground truth for eloquence. ECoG accuracy was examined for each task with 3 different criteria: exact (identical electrodes for ECoG activation and DES hits), adjacent (ECoG <1cm of DES hits), and adjacent within a predefined peritumoral region of interest (<2 cm from boundaries). RESULTS 32 DES hits (40% Auditory, 32% Action, 28% Obj) were observed across patients. Exact ECoG-DES accuracy ranged from 78%-90% [Object: Sens=11%, Spec=91%, PPV=6%, NPV=95%; Action: Sens=40%, Spec=93%, PPV=24%, NPV=97%; Auditory: Sens=69%, Spec=78%, PPV=19%, NPV=78%]. Adjacent ECoG-DES accuracy ranged from 82%-91% [Object: Sens=33%, Spec=92%, PPV=18%, NPV=97%; Action: Sens=44%, Spec=93%, PPV=25%, NPV=97%; Auditory: Sens=91%, Spec=81%, PPV=37%, NPV=99%]. When restricted to the peritumoral region, adjacent ECoG-DES accuracy ranged from 94%-97% [Object: Sens=14%, Spec=99%, PPV=25%, NPV=97%; Action: Sens=25%, Spec=99%, PPV=25%, NPV=99%; Auditory: Sens=100%, Spec=94%, PPV=54%, NPV=100%]. For patients with DES hits (N=10), all had at least 1 task activation <1 cm of DES hits, with 7/10 having convergence of activations across at least 2 tasks. CONCLUSIONS Negative ECoG mapping is strongly predictive of non-eloquence confirmed by DES for all naming tasks. Additionally, gamma band activation elicited by auditory naming within the peritumoral region is strongly predictive of eloquence. Findings support task-based ECoG language mapping for prediction of eloquence and identification of targets for DES confirmation.
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Dargahi-Malamir, Mehrdad, Amin Amini, Seyed Hamid Borsi, Hooshmand Hosseininejad, and Heshmatollah Tavakol. "Evaluation of Diagnostic Value of Urinary Deep Stick in Differentiating Different Types of Exudative Pleural Effusions and Differentiating Exudative Pleural Effusions From Transudates." Journal of Pioneering Medical Science 13, no. 5 (2024): 45–51. http://dx.doi.org/10.61091/jpms202413508.
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Objective: Rapid diagnosis is one of the key factors in pleural effusion management. Dipstick has been suggested for use in other body fluids, while its role in pleural effusion has not yet been confirmed. This study was conducted with the aim of investigating the diagnostic value of dipstick in differentiating types of pleural effusion. Methods: This prospective study was conducted on 70 patients diagnosed with pleural effusion requiring thoracentesis in Ahvaz teaching hospitals in 2022. Microbiological and cytological laboratory tests were performed on pleural fluid samples. At the same time, pleural fluid samples were evaluated with a urine dipstick. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of dipstick parameters in differentiating types of pleural effusion were calculated in comparison with the standard diagnostic method. Results: The dipstick protein test had a sensitivity of 100%, specificity of 96.23%, PPV of 89.5%, and NPV of 100% for differentiating exudative from transudative effusions, and a sensitivity, specificity, PPV, and NPV of 40%, 100%, 100%, and 61.5%, respectively, in detecting infectious exudative effusions. Sensitivity, specificity, PPV, and NPV of the dipstick leukocyte esterase test in differentiating exudative from transudative effusions were 100%, 56.6%, 42.5%, and 100%, respectively, and in detecting different types of exudative effusions, sensitivity, specificity, PPV, and NPV were all 100%. The dipstick glucose test effectively differentiated exudative from transudative effusions (sensitivity, specificity, PPV, and NPV of 82.35%, 79.25%, 56.0%, and 93.3%, respectively) and detected infectious exudative effusions (sensitivity, 93.33%, specificity, 93.30%, PPV, 93.3%, NPV, 91.3%). Sensitivity, specificity, PPV, and NPV of the dipstick pH test in differentiating exudative from transudative effusions were 100%, 64.15%, 76.9%, and 100%, respectively, and for different types of exudative effusions were 86.67%, 65.22%, 76.5%, and 78.9%, respectively. Conclusion: The dipstick strip was effectively accurate in detecting transudative from exudative and infectious from noninfectious exudative effusions. Therefore, this accurate, rapid, easy-to-use, and inexpensive tool could be used to distinguish different types of pleural effusion at the bedside, which could be especially helpful in resource-limited settings.
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Begum, Wahida, Ahmed Hossain, Waziha A. Jahan, Mahbuba Shirin, M. Abdullah Yusuf, and Aftabun Nahar. "Comparing Predictive power of CT-scan Findings among the Malignant Hepatic Mass patients." Journal of Science Foundation 12, no. 1 (2015): 2–6. http://dx.doi.org/10.3329/jsf.v12i1.23457.
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Background: CT-scan is useful for the detection of hepatic mass. Objective: The purpose of the present study was to see the predictive values of CT scan in the diagnosis of malignant hepatic mass. Methodology: This cross sectional study was carried out in the Department of Radiology and Imaging at Mymensingh Medical College Hospital (MMCH), Mymensingh, Banghabandhu Sheikh Mujib Medical University (BSMMU), Dhaka and Dhaka Medical College Hospital (DMCH), Dhaka during the period of 1st January 2006 to 31st December 2007. Patients admitted in the Department of Medicine and Department of Hepatobiliary of MMCH, BSMMU, and DMCH with the clinical diagnosis of fever, abdominal pain, anorexia, nausea/vomiting, loss of appetite, jaundice, weight loss and ascites were selected as study population. CT scan and histopathology were performed to all the patients. Result: A total number of 50 patients were recruited for this study.. The sensitivity for multiplicity was 71.4%, specificity was 63.6%, accuracy was 68%, PPV was 71.4% and NPV was 63.6%. The sensitivity for hypodensity as a sign of malignancy was 60.7%, specificity was 18.2%, accuracy was 42.0%, PPV was 48.6% and NPV was 26.7%. The sensitivity, specificity, PPV, NPV and accuracy of contrast enhancement were 100.0%, 22.7%, 62.2%, 100.0% and 66.0% respectively. Again the sensitivity, specificity, PPV, NPV and accuracy of detection of pressure effect on biliary apparatus by CT-scan were 100.0%, 22.7%, 62.2%, 100.0% and 66.0% respectively. Again the sensitivity, specificity, PPV, NPV and accuracy of detection of Lymphadenopathy by CT-scan were 35.7%, 95.5%, 90.9%, 53.8% and 62.0% respectively. The sensitivity, specificity, PPV, NPV and accuracy of detection of Portal vein invasion by CT-scan were 14.3%, 100.0%, 100.0%, 47.8% and 52.0% respectively. The sensitivity, specificity, PPV, NPV and accuracy of detection of hepatic vein invasion by CT-scan were 10.7%, 100.0%, 100.0%, 46.8% and 50.0% respectively. The sensitivity, specificity, PPV, NPV and accuracy of detection of inferior vena cava (IVC) invasion by CT-scan were 7.1%, 100.0%, 100.0%, 45.8% and 48.0% respectively. Conclusion: CT is a useful diagnostic tool for the detection of malignant hepatic masses.Journal of Science Foundation, 2014;12(1):2-6
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Henry, Jon C., Dennis Kiser, and Bhagwan Satiani. "A Critical Evaluation of Carotid Duplex Scanning in the Diagnosis of Significant Carotid Artery Occlusive Disease." Advances in Vascular Medicine 2015 (February 24, 2015): 1–6. http://dx.doi.org/10.1155/2015/905384.
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Carotid duplex (CD) scanning is the primary method of evaluating patients suspected of having extracranial carotid occlusive disease. It is incumbent on vascular laboratories (VL) to have internally validated criteria confirming overall accuracy, specificity (SP), sensitivity (SS), negative predictive value (NPV), and positive predictive value (PPV). Receiver operating characteristic (ROC) curves allow further analysis to update existing criteria. We correlated 127 internal carotid arteries studied by carotid duplex scanning and confirmatory modalities, which showed a SP of 83.3%, SS of 97.9%, NPV of 92.5%, PPV of 95%, and overall accuracy of 94.5% for >50% internal carotid artery stenosis. For >70% stenosis, SP was 88.8%, SS was 96.1%, NPV was 93.6%, PPV was 92.5%, and overall accuracy was 92.9%. ROC curves for the peak systolic velocities were used; for detecting a 50–69% stenosis range a sensitivity of 88%, specificity of 93%, NPV of 73%, and PPV of 97% were found. For detecting a 70–99% stenosis a sensitivity of 95%, specificity of 90%, NPV of 93%, and a PPV of 93% were found. All vascular laboratories must have a vigorous quality assurance program and must validate their own internal criteria or the recently promulgated consensus criteria for grading the severity of carotid stenosis by carotid duplex examination.
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Tailor, Imran K., Bilal Btoosh, Shaimaa Hamdy, et al. "Doublet Versus Triplet PET: Is END of Therapy PET Needed IF Interim PET Is Negative in Hodgkin'S or Diffuse Large B CELL Lymphoma?" Blood 128, no. 22 (2016): 5354. http://dx.doi.org/10.1182/blood.v128.22.5354.5354.
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Abstract Introduction: Baseline (PETb) and end of therapy (PETe) FDG PET is standard of care in the management of hodgkin's lymphoma (HL) and diffuse large B cell lymphoma (DLBCL). The role of interim PET (PETi) in HL is well established while its role in DLBCL is not well defined. We evaluated the utility of triPET (PETb, PETi and PETe ) in management of these two lymphomas. Methods: Retrospective review of PET archives revealed a total of 37 pts (HL=22, DLBCL=15). TriPET were acquired per accepted protocol. SUVmax and Deauville scores (DSc) were obtained from five target lesions, the average i.e. composite SUVmax & DSc were computed for each pt. Statistical analyses were performed with the composite maxSUV (cSUV) and Deauville scores (cDSc) (using EXCEL). Following statistics were performed (separately and combined in HL and DLBCL); mean+SD, PPV and NPV for complete response (CR) Vs. progressive disease (PD) on PETi using the following variables 1. cSUV and 2. cDSc and 3. delta change (DELT). Median progression free survival (PFS) was the clinical endpoint for response. Results: The mean PFS in our group was 17 and 15 months in HL and DLBCL respectively. Using cut off thresholds for intP to predict CR at cSUV<=2.0, , cDSC<=2.0 and DELT >=80%,. In HL: for cSUV- PPV 67%, NPV 95%; for DELT of cSUV PPV 100%, NPV 95%; for cDSC-PPV 30%, NPV 100%. In DLBCL: for cSUV- PPV 25%, NPV 100%; for DELT of cSUV PPV 33%, NPV 100%; for cDSC- PPV 50%, NPV 100%. Conclusion: The results from our series suggest that PETi has a role not only in HL but in DLBCL as well. Our modest cohort suggests that a negative PETi in DLBCL had a NPV of 100% across cSUV, cDSc and DELT, with regards to CR. Our data also suggests that PETe is not needed if PETi is -ve. While in HL subset, our results concur with results from other groups, this needs to be validated in a larger series. Disclosures No relevant conflicts of interest to declare.
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Baget-Bernaldiz, Marc, Romero-Aroca Pedro, Esther Santos-Blanco, et al. "Testing a Deep Learning Algorithm for Detection of Diabetic Retinopathy in a Spanish Diabetic Population and with MESSIDOR Database." Diagnostics 11, no. 8 (2021): 1385. http://dx.doi.org/10.3390/diagnostics11081385.
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Background: The aim of the present study was to test our deep learning algorithm (DLA) by reading the retinographies. Methods: We tested our DLA built on convolutional neural networks in 14,186 retinographies from our population and 1200 images extracted from MESSIDOR. The retinal images were graded both by the DLA and independently by four retina specialists. Results of the DLA were compared according to accuracy (ACC), sensitivity (S), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC), distinguishing between identification of any type of DR (any DR) and referable DR (RDR). Results: The results of testing the DLA for identifying any DR in our population were: ACC = 99.75, S = 97.92, SP = 99.91, PPV = 98.92, NPV = 99.82, and AUC = 0.983. When detecting RDR, the results were: ACC = 99.66, S = 96.7, SP = 99.92, PPV = 99.07, NPV = 99.71, and AUC = 0.988. The results of testing the DLA for identifying any DR with MESSIDOR were: ACC = 94.79, S = 97.32, SP = 94.57, PPV = 60.93, NPV = 99.75, and AUC = 0.959. When detecting RDR, the results were: ACC = 98.78, S = 94.64, SP = 99.14, PPV = 90.54, NPV = 99.53, and AUC = 0.968. Conclusions: Our DLA performed well, both in detecting any DR and in classifying those eyes with RDR in a sample of retinographies of type 2 DM patients in our population and the MESSIDOR database.
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Satish, Sanjana, Lohith K, Vinaya Manohara Gowda, Sriviruthi B, Prateek Parmeshwar Ugran, and Vishal S. Dharpur. "Role of transrectal ultrasound and MRI in the diagnosis and localisation of carcinoma prostate - A comparison of diagnostic efficacy of trus versus MRI." Panacea Journal of Medical Sciences 14, no. 1 (2024): 184–91. http://dx.doi.org/10.18231/j.pjms.2024.034.
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In this study, we wanted to correlate the findings of TRUS and MRI with regard to the diagnosis and localization of carcinoma prostate and local staging of carcinoma prostate. Our study included 43 men, with age ranging from 49 to 76 years. They underwent TRUS, MRI and TRUS guided twelve core biopsies after being suspected with prostate cancer based on high PSA values (greater than 4.0 ng /ml) or abnormal DRE findings. This study was conducted from April 2018 -June 2019. Imaging findings were confirmed with histopathology. TRUS used for the detection of malignancy had sensitivity, specificity, PPV and NPV as 69.70%, 80 %, 92% and 44.44 % respectively. The values were 63.16%, 83.33%, 75.00%, and 74.07% for the sensitivity, specificity, PPV and NPV of TRUS respectively for the detection of ECE. rnFor the detection of malignancy, the sensitivity, specificity, PPV and NPV of MRI was 87.88%, 70%, 90.63% and 63.64% respectively and 85.71%, 89.66%, 80.00% and 92.86% for the sensitivity, specificity, PPV and NPV of MRI respectively for detection of SVI. For detection of extracapsular extension (ECE), MRI had sensitivity, specificity, PPV and NPV of 78.95%, 83.33%, 78.95% and 83.33% respectively. When compared to TRUS, MRI is more useful in the diagnosis and accurate staging of prostate cancer. MRI can improve the false-negative biopsies resulting due to the inability of TRUS in detection of abnormal areas.
Dissertations / Theses on the topic "PPV and NPV"
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Majid, Safwat. "Åtgärder för ökad markanvändning i solcellspark : En tekno-ekonomisk fallstudie om potentialen hos bifacial och solföljare i Solpark Fyrislund." Thesis, Uppsala universitet, Solcellsteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447110.
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Solar parks are increasingly getting a larger market share of PV installations over the world, and have for the last couple of years managed to establish itself in the Swedish market. The market has for a long time been known for its decline in module prices, which has allowed an emergence of more efficient PV-techniques such as one-axis trackers and bifacial modules. Bifacial modules use the backside of modules for improved utiliziation of incoming light, while one-axis trackers have the ability to track the sun in order to maximise light absorption. These innovations have now caught the interest of companies willing to invest in large-scale PV-farms, where efficient land use is highly regarded. The aim of this thesis was to examine how bifacial modules and one-axis trackers perform in terms of system performance and profitabilty if implemented in 'Solpark Fyrislund', a solar park owned by Vasakronan AB. This was done by modelling and simulating cases in which said techniques were incorporated. The data was later used to estimate profitabilty of each investigated case. Results showed that the highest system performance and profitability was achieved by installing bifacial modules on the site. One-axis trackers are currently too expensive, require higher maintenance and has a higher demand for land, resulting in its profitability not being justified. It was also found that the current configuration could be optimized further for higher profit, by slightly reducing the pitch as well as increasing the tilt of the existing modules. The study should be followed up by further investigating the use of backtracking for one-axis trackers. Said innovations should also be more established in the Swedish market so that CAPEX- and OPEX prices become more accessible.
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Marques, Mónica Filipa Jesus. "Análise do periodo de concessão das PPP rodoviárias em Portugal." Master's thesis, Instituto Superior de Economia e Gestão, 2013. http://hdl.handle.net/10400.5/11424.
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Mestrado em Finanças (Mercados financeiros)<br>Portugal tem recorrido a parcerias público-privadas (PPP), particularmente no sector rodoviário, com o intuito de reduzir os encargos que este tipo de investimentos teria por via de uma contratação pública tradicional. No entanto, tem sido questionado se o período de concessão acordado nos contratos das PPP em Portugal será o adequado. Como a relação risco-retorno é preponderante, para o sector público e privado, dados os elevados riscos financeiros, políticos e de mercado, é necessário determinar o FCFF, VAL e WACC adequado para cada concessão em análise. Assim, esta investigação tem como objectivo proceder à aplicação dos métodos indicados a uma amostra de 7 Scut e 7 Subconcessões do sector rodoviário em Portugal, de modo a determinar um período mínimo de concessão e compará-lo com o período de concessão contratado, verificando os riscos assumidos pelas partes envolvidas na parceria. Recorreu-se a análises de sensibilidade e à simulação de Monte Carlo, de forma a analisar as variáveis que afectam o período de concessão. Na maioria das concessões analisadas os resultados apresentam evidências de que o interesse do Estado Português pode não ter sido assegurado, aumentando a sua exposição ao risco.<br>Portugal has been resorting to public-private partnerships (PPP), especially in the road sector, in order to reduce the costs that such investments would have through a traditional public procurement. However, the concession period agreed in the PPP contracts has often been questioned for being considered excessive. Since the risk-return ratio is important for the public and private sector, given the high financial, political and market risks it is necessary to determine the appropriate FCFF, NPV and WACC for each concession in analysis. Thus, this research aims to apply the methods given to a 7 Scut and 7 Subconcession sample from the road sector in Portugal in order to establish a minimum concession period and compare it to the hired concession period, verifying the assumed risks by the intervenients involved in the partnership. Sensibility analyses were used as was the Monte Carlo simulation so that the variables affecting the concession period would be analysed. In most analysed concessions the results show signs that Portuguese government?s interest may not have been assured, increasing their exposure to risk.
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Vergara, Gabriela Carolina Villamagua. "Ecofisiologia e produtividade de Bambusa, Eucalyptus e Salix em sistemas florestais de curta rotação." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154744.
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Previous issue date: 2018-06-04<br>Outra<br>Com a necessidade de buscar espécies florestais mais eficientes na utilização dos recursos naturais como luz, água e nutrientes, o que pode possibilitar um incremento da biomassa da parte aérea, o objetivo do presente trabalho foi o de quantificar as taxas de crescimento, eficiência da utilização da luz, água e nutrientes de florestas energéticas sob mesmas condições de solo, altitude e manejo. Foram utilizados plantios adensados de Bambusa vulgaris, híbrido espontâneo de Eucalyptus urophylla – clone AEC-144, híbrido interespecífico de Eucalyptus grandis × Eucalyptus urophylla - clone LW07 e Salix nigra. A determinação da produtividade primária líquida do tronco (PPLT), eficiência do uso da luz (EUL), eficiência do uso da água (EUA) foram obtidas através de acompanhamentos mensais e individuais em 15 plantas por espécie, no período de 12 meses. Foi obtido dados de: diâmetro e altura total das plantas, e posteriormente, taxa fotossintética (A), taxa transpiratória (E) e condutância estomática (gs). Foi realizada ainda a determinação do índice de vegetação e a coleta de amostras para determinação de macro e micronutrientes em laboratório. A espécie B. vulgaris apresentou o maior valor de biomassa por planta e, consequentemente, os maiores incrementos em matéria seca por planta (8,07 kg pl-1 e 1,56 kg pl-1 ano-1, respectivamente), no entanto, observou-se que clone de E. urophylla AEC-144 obteve maior eficiência no uso da luz por área (1,80 g MJ-1) e maior eficiência intrínseca no uso da água (68,09 μmol CO2 mol H2O-1). Em relação à eficiência do uso da água, o clone E. grandis × E. urophylla - LW07 apresentou o maior valor (4,93 μmol CO2 mol H2O-1). Nota-se que houve diferença em relação ao acúmulo de nutrientes entre as espécies estudadas, sendo que os maiores valores obtidos foi observado em B. vulgaris.<br>In the search for forest species more efficient in the use of resources (light, water and nutrients) to increase aerial biomass, this study aimed to quantify the growth, light, water and nutrients use efficiency of short rotation plantations under the same conditions of soil altitude and management of Bambusa vulgaris, the spontaneous hybrid of Eucalyptus urophylla - clone AEC-144, interspecific hybrid of Eucalyptus grandis × Eucalyptus urophylla - clone LW07 and Salix nigra. To determine truck net primary productivity trunk (TNPP), light use efficiency (LUE) and water use efficiency (WUE), 15 plants per treatment were monitored monthly for 12 months. Plants diameter and total height were collected, as well as photosynthetic rate (A), transpiration rate (E) and stomatal conductance (gs), using infrared gas analyzer (IRGA) (LI-COR 6400). Vegetation index was also obtained using AccuPAR (LP-80) ceptometer and were collected samples for determination of macro and micronutrients in the laboratory. Bambusa vulgaris was the species that obtained the highest biomass per plant ratio and consequently higher net primary productivity (8.07 kg pl-1 and 1.56 kg pl-1 year-1, respectively), however, clone AEC-144 showed higher light use efficiency per area (1.80 g MJ-1) and higher intrinsic water use efficiency (68.09 μmol CO2 mol H2O-1). Clone LW07 obtained the highest value (4.93 μmol CO2 mol H2O-1) of instantaneous water use efficiency, when compared to other species. There was a difference in nutrient accumulation between species, and the highest values were observed in Bambusa vulgaris.
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Beisler, Matthias Werner. "Modelling of input data uncertainty based on random set theory for evaluation of the financial feasibility for hydropower projects." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-71564.
Full textAbstract:
The design of hydropower projects requires a comprehensive planning process in order to achieve the objective to maximise exploitation of the existing hydropower potential as well as future revenues of the plant. For this purpose and to satisfy approval requirements for a complex hydropower development, it is imperative at planning stage, that the conceptual development contemplates a wide range of influencing design factors and ensures appropriate consideration of all related aspects. Since the majority of technical and economical parameters that are required for detailed and final design cannot be precisely determined at early planning stages, crucial design parameters such as design discharge and hydraulic head have to be examined through an extensive optimisation process. One disadvantage inherent to commonly used deterministic analysis is the lack of objectivity for the selection of input parameters. Moreover, it cannot be ensured that the entire existing parameter ranges and all possible parameter combinations are covered. Probabilistic methods utilise discrete probability distributions or parameter input ranges to cover the entire range of uncertainties resulting from an information deficit during the planning phase and integrate them into the optimisation by means of an alternative calculation method. The investigated method assists with the mathematical assessment and integration of uncertainties into the rational economic appraisal of complex infrastructure projects. The assessment includes an exemplary verification to what extent the Random Set Theory can be utilised for the determination of input parameters that are relevant for the optimisation of hydropower projects and evaluates possible improvements with respect to accuracy and suitability of the calculated results<br>Die Auslegung von Wasserkraftanlagen stellt einen komplexen Planungsablauf dar, mit dem Ziel das vorhandene Wasserkraftpotential möglichst vollständig zu nutzen und künftige, wirtschaftliche Erträge der Kraftanlage zu maximieren. Um dies zu erreichen und gleichzeitig die Genehmigungsfähigkeit eines komplexen Wasserkraftprojektes zu gewährleisten, besteht hierbei die zwingende Notwendigkeit eine Vielzahl für die Konzepterstellung relevanter Einflussfaktoren zu erfassen und in der Projektplanungsphase hinreichend zu berücksichtigen. In frühen Planungsstadien kann ein Großteil der für die Detailplanung entscheidenden, technischen und wirtschaftlichen Parameter meist nicht exakt bestimmt werden, wodurch maßgebende Designparameter der Wasserkraftanlage, wie Durchfluss und Fallhöhe, einen umfangreichen Optimierungsprozess durchlaufen müssen. Ein Nachteil gebräuchlicher, deterministischer Berechnungsansätze besteht in der zumeist unzureichenden Objektivität bei der Bestimmung der Eingangsparameter, sowie der Tatsache, dass die Erfassung der Parameter in ihrer gesamten Streubreite und sämtlichen, maßgeblichen Parameterkombinationen nicht sichergestellt werden kann. Probabilistische Verfahren verwenden Eingangsparameter in ihrer statistischen Verteilung bzw. in Form von Bandbreiten, mit dem Ziel, Unsicherheiten, die sich aus dem in der Planungsphase unausweichlichen Informationsdefizit ergeben, durch Anwendung einer alternativen Berechnungsmethode mathematisch zu erfassen und in die Berechnung einzubeziehen. Die untersuchte Vorgehensweise trägt dazu bei, aus einem Informationsdefizit resultierende Unschärfen bei der wirtschaftlichen Beurteilung komplexer Infrastrukturprojekte objektiv bzw. mathematisch zu erfassen und in den Planungsprozess einzubeziehen. Es erfolgt eine Beurteilung und beispielhafte Überprüfung, inwiefern die Random Set Methode bei Bestimmung der für den Optimierungsprozess von Wasserkraftanlagen relevanten Eingangsgrößen Anwendung finden kann und in wieweit sich hieraus Verbesserungen hinsichtlich Genauigkeit und Aussagekraft der Berechnungsergebnisse ergeben
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Bacci, Tommaso. "Experimental investigation on a high pressure NGV cascade in the presence of a representative lean burn aero-engine combustor outflow." Doctoral thesis, 2018. http://hdl.handle.net/2158/1128260.
Full textAbstract:
Experimental Investigation of the effects of a modern lean burn combustor outflow on the performance of a film-cooled NGV cascade. Evaluation of chamber flow field, NGV inlet/outlet aerothermal field, turbulence decay and adiabatic effectiveness on the NGV profiles
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Vasconcelos, Alexandre Felbinger Cossu de. "A parceria público-privada em bases e arsenais navais : reflexões e lições em distintos contextos nacionais." Master's thesis, 2014. http://hdl.handle.net/1822/30632.
Full textAbstract:
Dissertação de mestrado em Estudos de Gestão<br>O estudo aborda a temática do emprego da gestão privada na prestação de serviços
de manutenção e de reparo, em navios de guerra, nas Bases e Arsenais Navais. A
utilização da gestão privada em órgãos públicos ganhou força com o advento da Nova
Gestão Pública (NGP), a qual procurou trazer mais eficiência, eficácia e economicidade
aos negócios públicos. A investigação está fundamentada nas teorias da NGP, servindo
de apoio para a gestão das Bases e Arsenais Navais. A pesquisa torna-se relevante por
abordar um tema pouco debatido na literatura, e ainda, por discutir soluções para ganhos
de melhorias na eficiência, na eficácia e na economicidade da prestação de serviços nas
Bases e Arsenais Navais, fatores que influenciam na disponibilidade dos navios das
Marinhas e o cumprimento da sua missão. A busca por compreender as situações práticas
que envolvem o emprego da iniciativa privada na prestação de tais serviços conduziu o
trabalho a utilizar a metodologia de estudo de casos, investigando o contexto português e
o contexto inglês. Os resultados reforçam a importância da teoria quanto aos motivos de
se adotar um modelo de gestão privada em organizações públicas, quanto ao uso de
mecanismos de incentivo para conduzir o ente privado a alcançar a melhor prestação dos
serviços e quanto ao desenvolvimento do contrato relacional. Em termos práticos, os
resultados obtidos evidenciam alguns exemplos de como implementar os mecanismos de
incentivo e de como desenvolver os contratos relacionais. Estes resultados auxiliaram na
reflexão sobre uma possível Parceria Público-Privada (PPP) envolvendo o contexto
brasileiro, em especial, no Arsenal de Marinha do Rio de Janeiro (AMRJ), organização
da Marinha do Brasil, responsável por esses tipos de serviços. Assim, o estudo procurou
provocar o maior debate sobre o tema, contribuir para a busca de soluções mais eficientes
na prestação de serviços de manutenção de navios de guerra e subsidiar na tomada de
decisão caso seja adotado o emprego de uma PPP no AMRJ.<br>The study addresses the issue of the use of private management in the provision
of maintenance and repair services, on warships, in Navy Yards and Naval Bases. The
use of private management in public agencies gained momentum with the advent of New
Public Management (NPM), which sought to bring more efficiency, effectiveness and
economy to public affairs. The research is grounded in theories of NPM, serving as
support for the management of Navy Yards and Naval Bases. The research is relevant in
approaching a topic rarely discussed in the literature, and also in discussing solutions to
gain improvements in efficiency, effectiveness and economy of service provision in Navy
Yards and Naval Bases, factors which influence the availability of warships and the
fulfillment of its mission. The quest for understanding the practical situations involving
the use of the private sector in the provision of such services led the work using the
methodology of case studies, investigating the Portuguese and English contexts. The
results reinforce the importance of theory as to the reasons to adopt a model of private
management in public organizations, as to the use of incentive mechanisms to drive the
private party to achieve a better delivery of services and as to the development of a
relational contract. In practical terms, the results show some examples of how to
implement incentive mechanisms and how to develop relational contracts. These results
helped in thinking about a possible Public-Private Partnership (PPP) involving the
Brazilian context, especially in the Arsenal de Marinha do Rio de Janeiro (AMRJ),
organization of the Brazilian Navy, responsible for these types of services. Thus, the study
sought to provoke further debate on the subject, contributing to the search of more
efficient solutions in the provision of maintenance services of warships and support in
decision making if the use of a PPP in AMRJ is adopted.
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Beisler, Matthias Werner. "Modelling of input data uncertainty based on random set theory for evaluation of the financial feasibility for hydropower projects." Doctoral thesis, 2010. https://tubaf.qucosa.de/id/qucosa%3A22775.
Full textAbstract:
The design of hydropower projects requires a comprehensive planning process in order to achieve the objective to maximise exploitation of the existing hydropower potential as well as future revenues of the plant. For this purpose and to satisfy approval requirements for a complex hydropower development, it is imperative at planning stage, that the conceptual development contemplates a wide range of influencing design factors and ensures appropriate consideration of all related aspects.
Since the majority of technical and economical parameters that are required for detailed and final design cannot be precisely determined at early planning stages, crucial design parameters such as design discharge and hydraulic head have to be examined through an extensive optimisation process.
One disadvantage inherent to commonly used deterministic analysis is the lack of objectivity for the selection of input parameters. Moreover, it cannot be ensured that the entire existing parameter ranges and all possible parameter combinations are covered.
Probabilistic methods utilise discrete probability distributions or parameter input ranges to cover the entire range of uncertainties resulting from an information deficit during the planning phase and integrate them into the optimisation by means of an alternative calculation method.
The investigated method assists with the mathematical assessment and integration of uncertainties into the rational economic appraisal of complex infrastructure projects. The assessment includes an exemplary verification to what extent the Random Set Theory can be utilised for the determination of input parameters that are relevant for the optimisation of hydropower projects and evaluates possible improvements with respect to accuracy and suitability of the calculated results.<br>Die Auslegung von Wasserkraftanlagen stellt einen komplexen Planungsablauf dar, mit dem Ziel das vorhandene Wasserkraftpotential möglichst vollständig zu nutzen und künftige, wirtschaftliche Erträge der Kraftanlage zu maximieren. Um dies zu erreichen und gleichzeitig die Genehmigungsfähigkeit eines komplexen Wasserkraftprojektes zu gewährleisten, besteht hierbei die zwingende Notwendigkeit eine Vielzahl für die Konzepterstellung relevanter Einflussfaktoren zu erfassen und in der Projektplanungsphase hinreichend zu berücksichtigen.
In frühen Planungsstadien kann ein Großteil der für die Detailplanung entscheidenden, technischen und wirtschaftlichen Parameter meist nicht exakt bestimmt werden, wodurch maßgebende Designparameter der Wasserkraftanlage, wie Durchfluss und Fallhöhe, einen umfangreichen Optimierungsprozess durchlaufen müssen.
Ein Nachteil gebräuchlicher, deterministischer Berechnungsansätze besteht in der zumeist unzureichenden Objektivität bei der Bestimmung der Eingangsparameter, sowie der Tatsache, dass die Erfassung der Parameter in ihrer gesamten Streubreite und sämtlichen, maßgeblichen Parameterkombinationen nicht sichergestellt werden kann.
Probabilistische Verfahren verwenden Eingangsparameter in ihrer statistischen Verteilung bzw. in Form von Bandbreiten, mit dem Ziel, Unsicherheiten, die sich aus dem in der Planungsphase unausweichlichen Informationsdefizit ergeben, durch Anwendung einer alternativen Berechnungsmethode mathematisch zu erfassen und in die Berechnung einzubeziehen.
Die untersuchte Vorgehensweise trägt dazu bei, aus einem Informationsdefizit resultierende Unschärfen bei der wirtschaftlichen Beurteilung komplexer Infrastrukturprojekte objektiv bzw. mathematisch zu erfassen und in den Planungsprozess einzubeziehen. Es erfolgt eine Beurteilung und beispielhafte Überprüfung, inwiefern die Random Set Methode bei Bestimmung der für den Optimierungsprozess von Wasserkraftanlagen relevanten Eingangsgrößen Anwendung finden kann und in wieweit sich hieraus Verbesserungen hinsichtlich Genauigkeit und Aussagekraft der Berechnungsergebnisse ergeben.
Books on the topic "PPV and NPV"
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NA. Essn Socio: Down& Wrkbk W/Tests& Ppt& Res Nav. Addison Wesley Publishing Company, 2003.
Find full text
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Whitman, John, and Yohei Ono. Diachronic interpretations of word order parameter cohesion. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198747840.003.0004.
Full textAbstract:
This chapter uses statistical tools to investigate the interrelationship between typological features in the World Atlas of Language Structures Online (Dryer and Haspelmath 2013) in the WALS 201 language sample, with the objective of determining how crosscategorial word order generalizations might emerge as the result of syntactic change. Multiple Correspondence Analysis and a variety of cluster analyses show that word order features tend to group along the familiar lines of the Head Parameter. But there is an important caveat to this, previously noticed by Albu (2006): word order features in NP (e.g. [Order of noun and determiner], [Order of noun and adjective]) group separately from word order features in VP and PP, with the exception of [Order of noun and genitive]. We provide a diachronic explanation for this fact: nouns and their arguments may be reanalysed as PPs, or in the case of reanalysed nominalizations, clauses.
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NA. Mast Pub Speakg& CD& S/G W/Ppt Slides& Res Nav. Addison Wesley Publishing Company, 2003.
Find full textBook chapters on the topic "PPV and NPV"
1
Alleesaib, Muhsina. "Gaps, resumptive pronouns and the complementizer ki in Mauritian Creole relative clauses." In Contact Language Library. John Benjamins Publishing Company, 2025. https://doi.org/10.1075/coll.61.04all.
Full textAbstract:
Abstract The present chapter looks at the internal structure of restrictive relative clauses in Mauritian Creole. The first part of this chapter deals with the alternation between gaps and resumptive pronouns, and its relation to the syntactic position of the relativized NP. A list of all pronouns and locative forms which may occur as resumptives is provided. The data also suggest that resumption is only permissible with definite relativized DPs. The alternation between gaps and resumptives is further compared with Keenan and Comrie’s Noun Accessibility Hierarchy (1977). Gaps are used for subject and object relativisation. A resumptive form is required when possessors, prepositional phrases and comparative constituents are relativized. In double object constructions, the beneficiary object allows both gaps and resumptives. Pied-piping of PPs is also available in Mauritian Creole. The second part of the chapter looks at the distribution of ki versus that of the null complementizer. The form ki serves both as a complementizer and a relative pronoun. Its characteristics meet the criteria for both, according to the typology presented by De Vries (2002: 162). Since ki may sometimes be omitted in relative clauses, the last part of the chapter looks at its role in the avoidance of syntactically ambiguous sentences.
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"Study (date) n Patient Sensitivity Specificity PPV NPV type (%) (%)." In Cardiopulmonary Critical Care. CRC Press, 2002. http://dx.doi.org/10.3109/9780203427675-71.
Full text
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Warren Jim, Warren Debra, Yang Hong Yul, et al. "Prescribing History to Identify Candidates for Chronic Condition Medication Adherence Promotion." In Studies in Health Technology and Informatics. IOS Press, 2011. https://doi.org/10.3233/978-1-60750-806-9-634.
Full textAbstract:
Poor adherence to long-term prescription medication is a frequent problem that undermines pharmacological control of important risk factors such as hypertension. A medication possession ratio (MPR) can be calculated from Practice Management System (PMS) data to provide a convenient indicator of adherence. We investigate how well prior MPR predicts later MPR, taking MPR&lt;80% as indicative of &lsquo;non-adherence,&rsquo; to assess the potential value of MPR calculation on PMS data for targeting adherence promotion activities by general practices. We examine PMS data for two New Zealand metropolitan general practices, one with a predominantly Pacific caseload, across 2008 and 2009. We find prevalence of non-adherence in 2009 to be 51.63% (95% confidence interval [CI] 47.9-55.3) for patients at the Pacific practice and 28.09% (95% CI 25.0-31.1) at the other practice for patients who are demonstrably active with the practice in 2009. The positive predictive value (PPV) of 2008 non-adherence for 2009 non-adherence is 71.80% (95% CI, 66.5-77.1) and negative predictive value (NPV) 61.52% (95% CI 56.9-66.1) for the Pacific practice; PPV is 61.38% (95% CI 54.6-68.2) and NPV is 82.19% (95% CI 79.2-85.2) for the other practice. The results indicate good potential for decision support tools to target adherence promotion.
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Lagor Charles, Aronsky Dominik, Fiszman Marcelo, and Haug Peter J. "Automatic Identification of Patients Eligible for a Pneumonia Guideline: Comparing the Diagnostic Accuracy of Two Decision Support Models." In Studies in Health Technology and Informatics. IOS Press, 2001. https://doi.org/10.3233/978-1-60750-928-8-493.
Full textAbstract:
Background: In busy clinical settings, physicians often do not have enough time to identify patients for specific therapeutic guidelines. As a solution, decision support systems could automatically identify eligible patients and trigger computerized guidelines for specific diseases. Applying this idea to community-acquired pneumonia (CAP), we developed a Bayesian network (BN) and an artificial neural network (ANN) for identifying patients who have CAP and are eligible for a pneumonia guideline. Objective: The aim of this study was to determine whether the diagnostic accuracy of these two decision support models differs in terms of identifying CAP patients. Methods: We trained and tested the networks with a data set of 32,662 adult patients. For each network, we (1) calculated the specificity, the positive predictive value (PPV), and the negative predictive value (NPV) at a sensitivity of 95%, and (2) determined the area under the receiver operating characteristic curve (AUC) as a measure of overall accuracy. We tested for statistical difference between the AUCs using the correlated area z statistic. Results: At a sensitivity of 95%, the respective values for specificity, PPV, and NPV were: 92.3%, 15.1%, and 99.9% for the BN, and 94.0%, 18.6%, and 99.9% for the ANN. The BN had an AUC of 0.9795 (95% CI: 0.9736, 0.9843), and the ANN had an AUC of 0.9855 (95% CI: 0.9805, 0.9894). The difference between the AUCs was statistically significant (p =0.0044). Conclusions: The networks achieved high overall accuracies on the testing data set. Because the difference in accuracies is statistically significant but not clinically significant, both networks are equally suited to drive a guideline.
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Govindarajan, Usha, and Narasimhan K. "Approximation-Aided Epilepsy Detection Using Linear and Non-Linear Classifiers." In Machine Learning and AI Techniques in Interactive Medical Image Analysis. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-4671-3.ch008.
Full textAbstract:
Patients with brain-related symptoms and diseases are diagnosed using electrocardiogram (EEG) signals. Epilepsy in humans can be diagnosed from EEG signals. This chapter focuses on identification of seizure-free, seizure, epileptic, and normal EEG signals with minimum-length EEG signal. The algorithm could classify the seizure and normal EEG signals even for a length of 1000 samples per segment. The algorithm was tested on various EEG signals. The traits are extracted from the EEG signal and preprocessed and fed to five different classifiers to check the accuracy of the scheme. The algorithm provided a better accuracy of 99.8945%. The sample signals were taken from an EEG signal database available at University of Bonn. The proposed scheme was tested with performance measures such as specificity (SPE), NPV (negative predictive value), PPV (positive predictive value), ACC (accuracy), MCC (Matthews's correlation coefficient), and sensitivity (SEN). The test results proved that the proposed methodology could perform real-time epileptic seizure detection.
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Kiani, Arda, Fatemehsadat Rahimi, Pegah Soltani, Siamak Afaghi, Mehdi Kazempour Dizaji, and Atefeh Abedini. "Endobronchial Ultrasound: Pioneering Advances in Mediastinal Lymphadenopathy Diagnosis." In Ultrasound - The Next Step in Clinical Evaluation [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1005620.
Full textAbstract:
Endobronchial ultrasound (EBUS) represents a significant advancement in the diagnosis and management of mediastinal lymphadenopathy, offering a less invasive yet highly effective alternative to traditional methods. This chapter delves into the comprehensive role of EBUS, highlighting its diagnostic accuracy and clinical implications. It focuses on EBUS’s capability to analyze sonographic features of lymph nodes, including size, shape, echogenicity, and the presence of necrosis. These characteristics, when correlated with histopathological findings, are instrumental in differentiating between malignant and benign nodes, thereby enhancing diagnostic precision. The chapter also discusses the intricacies of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), emphasizing its diagnostic parameters such as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The convergence and discrepancies between EBUS and conventional diagnostic methods like spiral chest computed tomography (CT) scans are critically analyzed, underscoring EBUS’s role as both a screening and confirmatory tool in varied clinical scenarios, including tuberculosis prevalence and lung cancer staging. Ultimately, this chapter provides a forward-looking perspective on EBUS, advocating for ongoing technological advancements and research to enhance its specificity and application in modern pulmonology and thoracic oncology.
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Muylle, Katoo M., Pieter Cornu, Wilfried Cools, Kurt Barbé, Ronald Buyl, and Sven Van Laere. "Optimization of Performance by Combining Most Sensitive and Specific Models in Data Science Results in Majority Voting Ensemble." In Studies in Health Technology and Informatics. IOS Press, 2022. http://dx.doi.org/10.3233/shti220496.
Full textAbstract:
Ensemble modeling is an increasingly popular data science technique that combines the knowledge of multiple base learners to enhance predictive performance. In this paper, the idea was to increase predictive performance by holding out three algorithms when testing multiple classifiers: (a) the best overall performing algorithm (based on the harmonic mean of sensitivity and specificity (HMSS) of that algorithm); (b) the most sensitive model; and (c) the most specific model. This approach boils down to majority voting between the predictions of these three base learners. In this exemplary study, a case of identifying a prolonged QT interval after administering a drug-drug interaction with increased risk of QT prolongation (QT-DDI) is presented. Performance measures included accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Overall performance was measured by calculating the HMSS. Results show an increase in all performance measure characteristics compared to the original best performing algorithm, except for specificity where performance remained stable. The presented approach is fairly simple and shows potential to increase predictive performance, even without adjusting the default cut-offs to differentiate between high and low risk cases. Future research should look at a way of combining all tested algorithms, instead of using only three. Similarly, this approach should be tested on a multiclass prediction problem.
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La Cruz, Alexandra, Erika Severeyn, Mónica Huerta, and Sara Wong. "Support Vector Machine Technique as Classifier of Impaired Body Fat Percentage." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2021. http://dx.doi.org/10.3233/faia210188.
Full textAbstract:
Excess weight and obesity are indicators of an unhealthy or harmful accumulation of fat that can be dangerous to health. Body mass index (BMI) refers to height-to-weight radio and is often used to identify overweight and obesity in adults. Although BMI is commonly used to diagnose obesity and overweight, it is ineffective in differentiating between high muscle mass and elevated body fat mass. Body fat percentage (BF%) is one of the best predictors of obesity because it quantifies adipose tissue. The Deurenberg equation is among the indirect methods to measure BF%; it uses BMI, age, and sex as parameters to calculate the BF%. Machine learning techniques demonstrated to be a good classifier of overweight, obesity, and diseases related to insulin resistance and metabolic syndrome. This study intends to evaluate anthropometric parameters as classifiers of BF% alteration using support vector machines and the Deurenberg equation for BF% estimation. The database used consisted of 1978 individuals with 24 different anthropometric measurements. The results suggest the SVM as a suitable technique for classifying individuals with normal and abnormal BF% values. Accuracy, F1 score, PPV, NPV, and sensitivity were above 0.8. Besides, the specificity value is below 0.7, which indicates that false positives may occur. As future work, this research intends to apply neural networks as a classification technique.
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Luo, Jiamin, Alex Noel Joseph Raj, Nersisson Ruban, and Vijayalakshmi G. V. Mahesh. "Segmentation of Optic Disc From Fundus Image Based on Morphology and SVM Classifier." In Research Anthology on Improving Medical Imaging Techniques for Analysis and Intervention. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-7544-7.ch024.
Full textAbstract:
Color fundus image is the most basic way to diagnose diabetic retinopathy, papillary edema, and glaucoma. In particular, since observing the morphological changes of the optic disc is conducive to the diagnosis of related diseases, accurate and effective positioning and segmentation of the optic disc is an important process. Optic disc segmentation algorithms are mainly based on template matching, deformable model and learning. According to the character that the shape of the optic disc is approximately circular, this proposed research work uses Kirsch operator to get the edge of the green channel fundus image through morphological operation, and then detects the optic disc by HOUGH circle transformation. In addition, supervised learning in machine learning is also applied in this chapter. First, the vascular mask is obtained by morphological operation for vascular erasure, and then the SVM classifier is segmented by HU moment invariant feature and gray level feature. The test results on the DRIONS fundus image database with expert-labeled optic disc contour show that the two methods have good results and high accuracy in optic disc segmentation. Even though seven different assessment parameters (sensitivity [Se], specificity [Sp], accuracy [Acc], positive predicted value [Ppv], and negative predicted value [Npv]) are used for performance assessment of the algorithm. Accuracy is considered as the criterion of judgment in this chapter. The average accuracy achieved for the nine random test set is 97.7%, which is better than any other classifiers used for segmenting Optical Disc from Fundus Images.
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Luo, Jiamin, Alex Noel Joseph Raj, Nersisson Ruban, and Vijayalakshmi G. V. Mahesh. "Segmentation of Optic Disc From Fundus Image Based on Morphology and SVM Classifier." In Handbook of Research on Deep Learning-Based Image Analysis Under Constrained and Unconstrained Environments. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-6690-9.ch007.
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Color fundus image is the most basic way to diagnose diabetic retinopathy, papillary edema, and glaucoma. In particular, since observing the morphological changes of the optic disc is conducive to the diagnosis of related diseases, accurate and effective positioning and segmentation of the optic disc is an important process. Optic disc segmentation algorithms are mainly based on template matching, deformable model and learning. According to the character that the shape of the optic disc is approximately circular, this proposed research work uses Kirsch operator to get the edge of the green channel fundus image through morphological operation, and then detects the optic disc by HOUGH circle transformation. In addition, supervised learning in machine learning is also applied in this chapter. First, the vascular mask is obtained by morphological operation for vascular erasure, and then the SVM classifier is segmented by HU moment invariant feature and gray level feature. The test results on the DRIONS fundus image database with expert-labeled optic disc contour show that the two methods have good results and high accuracy in optic disc segmentation. Even though seven different assessment parameters (sensitivity [Se], specificity [Sp], accuracy [Acc], positive predicted value [Ppv], and negative predicted value [Npv]) are used for performance assessment of the algorithm. Accuracy is considered as the criterion of judgment in this chapter. The average accuracy achieved for the nine random test set is 97.7%, which is better than any other classifiers used for segmenting Optical Disc from Fundus Images.
Conference papers on the topic "PPV and NPV"
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Bansal, Nidhi, A. Suneja, K. Guleria, et al. "Role of human epididymis protein 4 for detection of ovarian carcinoma in adnexal masses: A pilot study." In 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685305.
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Introduction: HE4 is a novel tumour biomarker used for early diagnosis of ovarian cancer. This study evaluated the diagnostic accuracy of HE4 alone and in combination with CA125, risk of malignancy index (RMI), risk of malignancy algorithm (ROMA). Methods: It was a cross sectional study conducted recruiting 88 women with adnexal masses who were planned for surgery. After baseline work up and ultrasound examination, serum samples were collected for estimation of CA 125 and HE4 levels. Serum HE4 levels were estimated using ELISA kit. RMI and ROMA score were calculated and diagnostic accuracy of HE4, CA 125, RMI, ROMA and their combination were compared. Cut off for HE4 and ROMA score were calculated using ROC curve. Results: Of 88 subjects, 66 were analyzed with 19 malignant (including 5 LMP) and 47 benign cases. The median value of HE4 among malignant cases was found to be significantly higher than among the benign cases. PPV and NPV of HE4 at a cut off 130.8 pMol/ml was 85.7% and 77.9% respectively. Highest PPV (88.9%) with acceptable NPV (80.7%) was found with ROMA followed by HE4 (PPV 85.7%; NPV 77.97%), RMI (PPV 76.92%; NPV 83%) and CA125 (PPV 52%; NPV 80.85%). Conclusion: HE4 levels were lower in Indian population both in malignant and benign tumours as compared to other studies. HE4 is a good discriminator and gives best accuracy when it is combined with CA125 in a logistic algorithm, ROMA.
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Ahortor, E., S. Mahazu, T. Manful, A. Erber, and A. Ablordey. "Evaluation of an IS2404 LAMP protocol, a simple and rapid test for diagnosis of Buruli ulcer in low-resource settings." In MSF Scientific Days International 2024. MSF-USA, 2024. http://dx.doi.org/10.57740/mat4h7.
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INTRODUCTION Buruli ulcer caused by Mycobacterium ulcerans is a devastating necrotic skin disease. PCR, recommended for confirmation of Buruli ulcer by WHO, requires an adequately equipped laboratory, often delaying diagnosis and treatment of patients in remote or humanitarian settings. We aimed to assess loop- mediated isothermal amplification (LAMP), which is a molecular assay for isothermal amplification of DNA suggested for timely diagnosis of Buruli ulcer in low-resource settings. METHODS This study combines quantitative and qualitative methods. First, we evaluated a simple rapid syringe DNA extraction method (SM) in comparison with a conventional extraction method (CM), followed by a LAMP assay targeting IS2404 for the detection of M ulcerans, either using a pocket warmer (pw) or a heat block (hb) for incubation of the reaction. 83 clinical specimens (swabs and fine-needle aspirates from different centres in Ghana) were tested. We assessed sensitivity, specificity, and positive and negative predictive value (PPV and NPV). Second, we explored the diagnostic workflow for Buruli ulcer at a community-based health centre in rural Ghana, a potential target setting. We used observations and interviews with researchers and healthcare workers (HCWs) and community-based surveillance volunteers. We discuss evaluation results in relation to the target setting and requirements of a target product profile for Buruli ulcer diagnosis. RESULTS DNA extraction using SM followed by IS2404 PCR (IS2404 PCRSM) identified M ulcerans DNA in 73 of 83 clinical specimens. The sensitivity, specificity, PPV, and NPV of IS2404 PCRSM were 90.12%, 100%, 100%, and 65.21%, respectively, compared with the reference standard IS2404 PCR with the CM protocol. Evaluation of the LAMP assay on 64 SM DNA extracts showed a sensitivity, specificity, PPV, and NPV of 83.6%, 100%, 100%, and 50%, respectively, using either pw (pwLAMPSM) or hb (hbLAMPSM) for incubation, compared with the same reference standard. The limit of detection of both pwLAMPSM and hbLAMPSM was 30 target copies. Interviews confirmed that, despite great engagement from HCWs and volunteers, patients met challenges regarding transport and costs for initial diagnosis and follow- up and often sought alternative treatments first. Diagnostic confirmation via PCR in a reference laboratory led to a delay in the initiation of treatment. A diagnosis at the point of care, following clinical screening, was considered advantageous to prevent delays and loss to follow-up, therefore ensuring timely patient treatment. CONCLUSION Our findings support the potential use of pwLAMP for rapid diagnosis of Buruli Ulcer in patients with a suspected infection at the community or primary health-care level, with limited equipment and without reliable electricity supply such as found in humanitarian settings.
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Vieira, Daniella Serafin Couto, Sandro Wopereis, Laura Otto Walter, and Maria Claudia Santos da Silva. "VALIDATION OF IMMUNOPHENOTYPING BY FLOW CYTOMETRY IN THE INVESTIGATION OF DIAGNOSTIC AND PROGNOSTIC MARKERS FOR BREAST CANCER." In Scientifc papers of XXIII Brazilian Breast Congress - 2021. Mastology, 2021. http://dx.doi.org/10.29289/259453942021v31s1021.
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Introduction: Due to the high prevalence of breast cancer, it has a major financial impact on health systems. Currently, the diagnosis is made by morphological and immunohistochemical analysis (IHC). However, this methodology has some limitations. Therefore, methodologies capable of rapid and safe detection of tumor cells are needed, which can assist those already in use. Objectives: To validate immunophenotyping by flow cytometry (FC) in the investigation of diagnostic and prognostic markers for breast cancer; and to investigate lymphocytes subtypes infiltrated in the tumor and their relationship with tumor development. Methods: 52 breast tumor samples were sectioned and macerated in phosphatesaline buffer and stained with antibodies against estradiol (RE), progesterone (RP), HER2, Ki67, CD3, CD4, CD8 and CD45 receptors and analyzed by FC. All results were compared with IHC (reference method) in relation to sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), except for Ki67, where bias was compared between methodologies and correlation between lymphocyte subtypes and tumor characteristics. Results: The comparison of the FC with the IHC for each marker presented the RE analysis (sensitivity: 75%, specificity: 90%, PPV: 96.7%, VPN: 47.4%); PR analysis (sensitivity: 72%, specificity: 70%, PPV: 79.3%, VPN: 60.8%); analysis of HER2 (sensitivity: 80%, specificity: 90.2%, PPV: 66.7%, VPN: 94.9%). The analysis of Ki67 by FC was shown to be equivalent to IHC, with the advantage of not having an observational bias. No correlations were observed between the molecular subtype intratumor lymphocyte population profile and the tumor histological grade. Conclusion: The results show the FC’s ability to safely and quickly detect breast cancer markers used in clinical practice. It is believed that the use of FC, in conjunction with morphological analysis and IHC, can overcome the individual limitations of each of the methodologies and provide reliable results in a faster and more efficient way, which will result in faster diagnoses and more accurate prognoses, directly benefiting patients.
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Clarke, Paula, Henrique Lima Couto, Eduardo Carvalho Pessoa, et al. "The potential role of cavity margins sampling shaving to predict complete tumor resection by vacuum-assisted excision." In Brazilian Breast Cancer Symposium 2024. Mastology, 2024. http://dx.doi.org/10.29289/259453942024v34s1021.
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Objective: The objective of this study was to evaluate the cavity margins sampling shaving (CMSH) as a predictor of complete tumor resection (CR) by VAE. Methodology: This is a retrospective database analysis of 120 ductal carcinoma in situ (DCIS) and invasive cancers (IC) of the breast, smaller than 20 mm (image), submitted to diagnostic VAE-CMSH and standard surgery (SS) from June 2021 to December 2023. VAE definition: more than 12 core samples (CS) with 7G needle or 18 samples with 10G needle. CMSH definition: core sampling the round residual cavity circumference after VAE. CMSH-CS were allocated in an exclusive bottle and sent to the laboratory. Demographic, imaging, pathology, VAE, CMSH, and SS data were collected. CMSH was compared with SS (gold standard) to predict CR. The SPSS® 20.0 software was used for statistical analyses. Results: The mean age was 58.5 years; the mean imaging tumor size (iT) was 12.4 mm; masses were 68 (56.7%); the mean VAE-CS was 29.5 weighting 9.3 g; the mean CMSH-CS was 10.9 weighting 6.2 g; the mean final pathological tumor size (pT) is 7.5 mm. IC were 75 (62.5%) and DCIS 45 (37.5%); 46 (38.3%) were CR by VAE-CMSH and 74 (61.7%) were not. CMSH was negative for residual cancer in 52 (43.3%) and positive in 68 (56.7%). CMSH sensitivity (SENS) was 70.7%, specificity (ESP) was 66.7%, positive predictive value (PPV) was 77.9%, negative predictive value (NPV) was 57.7%, and false negative rate (FNR) was 29.3%. The variables significatively related to VAE-CMSH CR were the pathological tumor size in the CMSH (p=0.014) and pT (p=0.023); to true negative CMSH was pT (p=0.041); to false negative CMSH were calcifications (p=0.030); IC associated to DCIS (p<0.001) and the DCIS tumor size in the SS (p=0.016). For pure IC, CMSH SENS was 88.9%, ESP was 83.3%, PPV was 88.9%, NPV was 83.3% and FNR was 11.1%. Conclusion: CMSH may be a potential approach to predict CR by VAE. Potential selected criteria for future intention to CR trials comparing VAECMSH to SS should be small masses of pure IC without calcifications.
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Loureiro, Eduardo Sales, Luna Vasconcelos Felippe, Ana Luiza Cotta Mourão Guimarães, and Anna Carolina Dockhorn de Menezes Carvalho Costa. "HINTS protocole and it’s accuracy to identify posterior circulation stroke: a review." In XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.446.
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Introduction: The HINTS protocol is important to differentiate peripheral from central vertigo in Acute Vestibular Syndrome (AVS). There are studies that show almost 1/3 of patients have posterior circulation stroke. It is important to investigate why this happens. Objectives: Review the accuracy of HINTS test in the diagnosis of posterior circulation stroke. Methods: Review conducted in PubMed using key words “HINTS AND ACCURACY AND STROKE”. The search found 9 articles, 7 of which were included. Results: Tehrani et al. (2014) studied HINTS’s accuracy when associated with hearing loss, resulting on a bigger accuracy than MRI. Newman- Toker et al. (2013) found that HINTS score was superior than ABCD2 in identifying AVS caused by stroke. From Carmona et al. (2016), HINTS had 100 % sensibility and 94,4% specificity and emphasized ataxia evaluation’s importance, once all patients with central etiology had a grade of ataxia. Krishnan et al. (2019) HINTS had 59,9% Negative Predictive Value (NPV) and 97,2 % Positive Predictive Value (PPV) related to stroke, same PPV was found by Sankalia et al. (2021). Ohle et al. (2020) observed that HINTS done by a neurologist was more accurate than studies that mixed neurologists and emergency physicians. Dmitriew et al. (2021) saw that HINTS was used wrongly in non-specific emergency departments, once only 3,1% patients tested had AVS and 96,9% wrongly tested had false positives. Conclusion: The HINTS is a valuable instrument in the clinical use and the training for better practical application needs incentive in emergency departments.
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Buzatto, Isabela Panzeri Carlotti, Daniel Guimarães Tiezzi, Sarah Abud Recife, et al. "Machine learning can reliably predict malignancy of BI-RADS 4a and 4b breast lesions based on clinical and ultrasonographic features." In Brazilian Breast Cancer Symposium 2023. Mastology, 2023. http://dx.doi.org/10.29289/259453942023v33s1002.
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Objective: The objectives of this study were to establish the most reliable machine learning model to predict malignancy in BI-RADS 4a and 4b breast lesions and optimize the negative predictive value to minimize unnecessary biopsies. Methodology: We included clinical and ultrasonographic attributes from 1,250 breast lesions from four institutions classified as BI-RADS 3, 4a, 4b, 4c, 5, and 6. We selected the most informative attributes to train the models in order to make inferences about the diagnosis of BI-RADS 4a and 4b lesions (validation dataset). Using the best parameters and hyperparameters selected, we tested the performance of nine models and 1,530 ensemble models. Results: The most informative attributes were shape, margin, orientation, and size of the lesions, the resistance index of the internal vessel, the age of the patient, and the presence of a palpable lump. The highest mean NPV was achieved with XGBoost (93.6%). The final performance of the best ensemble model was NPV=96.4%, sensitivity=81.5%, specificity=84.1%, PPV=46.8%, f1-score=59.5%, and the final accuracy=83.7%. Age was the most important attribute to predict malignancy. The use of the final model associated with the patient’s age would reduce by 51% the number of biopsies in women with BI-RADS 4a or 4b lesions. Conclusion: Machine learning can predict malignancy in BI-RADS 4a and 4b breast lesions identified by ultrasonography, based on clinical and ultrasonographic features. Our final prediction model would be able to avoid 51% of the 4a and 4b breast biopsies, without missing any cancers.
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Mukhopadhyay, Asima, Nicola Curtin, and Richard Edmondson. "Clinico-pathological correlation of homologous recombination status in epithelial ovarian cancer: Surgeon’s perspective." In 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685292.
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Background: TCGA data using expensive multi-modality diagnostic platforms have shown that 50% epithelial ovarian cancers (EOCs) are estimated to be homologous recombination (HR) deficient (HRD). We developed a functional assay for HR using gamma H2AX-Rad51 immunofluoresence.[1] Methods: Primary cultures were developed in 50 consecutive EOCs from ascetic fluid and HR assay was performed. Results: 50% patients were HRD based on the functional assay and show improved ex-vivo chemosensitivity to PARP inhibitor (PARPi) (PPV = 92%, NPV = 100%). HRD patients showed improved platinum sensitivity (53.8% vs 16.7%), survival (12 month OS - 41.7% vs. 11.5%) and optimal cytoreduction (80% vs. 62%) rates compared to HR competent (HRC) tumours which are less responsive and represent an unmet clinical need. Conclusions: Personalised surgical and chemotherapeutic strategies may be developed for HR stratified EOCs. Primary surgery may be the preferred approach in HRC due to poor chemoresponse; surgical expertise/environment should be optimised to ensure optimal surgical outcome. Intra-operative hyperthermic treatment and selective HR inhibitors may improve subsequent chemoresponse in HRC and are currently being investigated.
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Kerschberger, B., N. Ntshalintshali, M. Mafomisa, et al. "High burden of sexually transmitted infections and poor diagnostic performance of syndromic approaches within a decentralised HIV care setting in Eswatini." In MSF Scientific Day International 2023. MSF-USA, 2023. http://dx.doi.org/10.57740/4e0e-e138.
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INTRODUCTION Sexually transmitted infections (STI’s) are a public health threat. Syndromic approaches based on clinical symptoms have been suggested as having poor diagnostic performance, particularly in the type of settings where MSF is operational. We assessed the burden of STI’s and the diagnostic performance of a syndromic approach within an MSF-supported HIV/STI project in Eswatini. METHODS We conducted a cross-sectional study, enrolling adults accessing routine HIV testing and antiretroviral care services in six clinics in Shiselweni, from July 2022 to January 2023. HIV testing counselors performed HIV testing and nurses assessed patients for STI’s. Laboratory investigations included antibody-based rapid diagnostic tests (RDT’s) for Treponema pallidum (TP), hepatitis B (HBV) and hepatitis C (HBC). The molecular platform Xpert was used to test urine samples for Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG), Trichomonas vaginalis (TV), Mycoplasma genitalium (MG), vaginal/anal swabs for human papillomavirus (HPV), and plasma for HIV viraemia to test for acute HIV infection (HIV). We calculated the prevalence of STI’s, and assessed diagnostic performance of a syndromic approach to diagnose male urethritis (MUS) and vaginal discharge (VDS) syndromes, versus laboratory-based testing. ETHICS This study was approved by the Eswatini Health and Human Research Review Board and by the MSF Ethics Review Board. RESULTS Of 1,041 study participants, 682 were women (65.5%), and the median age was 30 (interquartile range, IQR, 24-38) years. Overall, 280 (26.9%) were known HIV-positive and of 755 with unknown HIV status, 30 (4.0%) were newly diagnosed with HIV, of whom seven (23.3%) had AHI. 308 (29.6%) patients had at least one of the following three pathogens identified: NG 121 (11.6%); CT 155 (14.9%); TV 109 (10.5%). MG was detected in 33/330 participants (10.0%). In addition, 105 (10.1%) had antibodies against TP, 49 (4.7%) against HBV, and three (0.3%) against HCV. HPV prevalence was higher in tested women (104/196; 53.1%) versus men (5/27; 18.5%; p=0.001). Prevalence of NG/CT/TP was highest in newly-diagnosed HIV cases (48.2%) versus known HIV-positive cases (26.8%, p=0.019). Based on the syndromic approach, 188/634 (29.7%) had a VDS, and 97/334 (29.0%) a MUS. Diagnostic performance of the syndromic approach was better in men (MUS: sensitivity: 66.7%, specificity 87.5%; positive predictive value, PPV, 70.1%, negative predictive value, NPV, 85.7%), versus women (VDS: sensitivity 35.9%, specificity 72.9%; PPV 35.1%, NPV 73.5%). CONCLUSION A high burden of STI’s in Eswatini and poor diagnostic ability of the syndromic approach in this setting, calls for new approaches for STI care in MSF-supported sexual and reproductive health programmes in resource-poor settings. CONFLICTS OF INTEREST None declared
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Carvalho, Viviane Amaral, Thais Lima Silva, Luciano Mariano, et al. "THE ADDENBROOKE’S COGNITIVE EXAMINATION–REVISED (ACE-R) IN THE DIFFERENTIAL DIAGNOSIS BETWEEN ALZHEIMER’S DISEASE AND BEHAVIORAL VARIANT FRONTOTEMPORAL DEMENTIA: A POWERFUL LOGARITHM." In XIII Meeting of Researchers on Alzheimer's Disease and Related Disorders. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1980-5764.rpda017.
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Background: The differential diagnosis between Alzheimer’s disease (AD) and behavioral variant frontotemporal dementia (bvFTD) is challenging, justifying improvement of cognitive tools for use in clinical practice. Objective: To develop a new logarithm based on discriminative items of the ACE-R. Methods: The ACE-R was administered to 102 patients with mild dementia due to probable AD and 37 with mild probable bvFTD. Mokken scaling analysis was applied to identify the latent trait on the AD Group. Multivariate logistic regression and ROC curve analysis were carried out. Results: Mean total scores in ACE-R were 70.2 ± 10.8 in AD and 72.2 ± 11.1 in bvFTD. AD Mokken ACE-R (AMokACE-R) comprises 12 items measuring the same latent concept. Logistic regression with cross-validation pointed that AMokACE-R + Age + Sex-male + ACE-R subitems Orientation and Memory share importance as independent variables (p <0.05). The proposed logarithm reached an area under the curve of 0.922, with 88% sensitivity/specificity, 71% PPV and 96% NPV. Conclusion: The new logarithm using the ACE-R achieved high diagnostic accuracy in discriminating AD and bvFTD, showing superiority to previous findings. Further analysis in larger samples, with biomarkers or pathological confirmation, are necessary to confirm these findings.
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Vidal, JR, and OR Vidal. "CLINICAL EFFICACY OF THE AUTOMATED METHOD BASED ON ARTIFICIAL INTELLIGENCE TO IDENTIFY KOCH BACILLI." In Resumos do 55º Congresso Brasileiro de Patologia Clínica/Medicina Laboratorial. Zeppelini Editorial e Comunicação, 2023. http://dx.doi.org/10.5327/1516-3180.141s2.7481.
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Objective: Tuberculosis is a disease with a great impact on public health, so it is important to have new tools to help diagnose, reduce exposure and be economical. So artificial intelligence is a useful tool to help in the process of reading bacilloscopies. Therefore, the aim of the study was to develop and evaluate the clinical efficacy of the automated method based on artificial intelligence to identify koch bacilli in ZiehlNeelsen (ZN) stained sheets. Method: Application study. A pilot study was carried out. An automated method (based on AI) for the identification of mycobacteria was developed. We prepared a training data set with 85 positive and 85 negative slides with the same size and color, from ZN-stained slides scanned and published on the internet. Which were confirmed by two clinical pathologists confirming positive and negative lamina. A neural network model based on machine learning algorithms was created to identify Koch’s bacillus through its characteristics, in addition to training the neural network to improve identification. There was a sample of 44 slides (22 positives). Sensitivity, specificity, PPV, NPV, LR were estimated. Conclusion: The artificial intelligence program presented good sensitivity and specificity to identify koch bacilli. References: 1. Anshu S, Anurag S, Rahul M, et al. An accurate artificial intelligence system for the detection of pulmonary and extra pulmonary Tuberculosis. J Tuberculosis. 2021; 131: 102143. 2. Montezuma D, Oliveira SP, Neto PC, et al. Annotating for artificial intelligence applications in digital pathology: a practical guide for pathologists and researchers. Mod Pathol. 2023; 36(4): 100086.
Reports on the topic "PPV and NPV"
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Thomas Austin, Evan, Paul Kang, Chinedu Mmeje, et al. Validation of PI-RADS v2 Scores at Various Non-University Radiology Practices. Science Repository, 2021. http://dx.doi.org/10.31487/j.aco.2021.02.02.
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Purpose: The purpose of this study was to validate the second version of the Prostate Imaging Reporting and Data System (PI-RADSv2) scores in predicting positive in-bore MRI-guided targeted prostate biopsy results across different non-university related institutions. The study focuses on PI-RADS v2 scoring because during the study period, PI-RADS v2.1 had not been released. Materials and Methods: This was a retrospective review of 147 patients who underwent multiparametric magnetic resonance imaging (mpMRI) of the pelvis followed by in-bore MRI-guided targeted prostate biopsy from December 2014 to May 2018. All lesions on mpMRI were rated according to PI-RADS v2 criteria. PI-RADS v2 scores were then compared to MR-guided biopsy results and pre-biopsy PSA values. Results: Prostate Cancer (PCa) was detected in 54% (80/147) of patients, with more prostate cancer being detected with each subsequent increase in PI-RADS scores. Specifically, biopsy results in patients with PI-RADS 3, 4, and 5 lesions resulted in PCa in 25.6% (10/39), 58.1% (33/55), and 86.0% (37/43) respectively. Clinically significant PCa (Gleason score ≥7) was detected in 17.9% (7/39), 52.7% (29/55), and 72% (31/43) of cases for PI-RADS 3, 4, and 5 lesions respectively. When the PI-RADS scoring and biopsy results were compared across different institutions, there was no difference in the PI-RADS scoring of lesions or in the positive biopsy rates of the lesions. The sensitivity, specificity, PPV, and NPV for PI-RADS 3-4 lesions were also not statistically different across the institutions for detecting Gleason 7 or greater lesions. Conclusion: Our results agree with prior studies that higher PI-RADS scores are associated with the presence of clinically significant PCa and suggest prostate lesions with PI-RADS scores 3-5 have sufficient evidence to warrant targeted biopsy. The comparison of PI-RADS score across different types of non-university practices revealed no difference in scoring and biopsy outcome, suggesting that PI-RADS v2 can be easily applied outside of the university medical center setting. Clinical Relevance: PI-RADS v2 can be applied homogeneously in the non-university setting without significant difference in outcome.
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Wright, Wendy, M. Gregory, and Aaron Rinehart. Fixed-station water quality monitoring at Cumberland Island National Seashore: 2011 data summary. National Park Service, 2012. https://doi.org/10.36967/2190432.
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In 2006, the National Park Service (NPS) Southeast Coast Network (SECN) Inventory and Monitoring Program began collecting water-quality data in the estuarine waters near Cumberland Island National Seashore (CUIS) as part the NPS Vital Signs monitoring program. The CUIS station collected pH, dissolved oxygen, temperature, salinity, conductivity, turbidity and waterlevel data. Additional water-quality measurements were made by SECN staff and include monthly measurements of water clarity conditions, nutrients (total dissolved phosphorus [TDP] and total dissolved nitrogen [TDN]), and chlorophyll a levels. Information provided by this monitoring program is designed to help managers understand trends and variability related to water-quality conditions in and around park waters. This report includes data from January through December, 2011. High levels of TDP were the most common cause of poor water-quality ratings across all sites during the winter and spring based on monthly water quality samples. TDN levels were all within the range considered fair whereas chlorophyll levels rated as good to fair during this same period. Dissolved oxygen concentrations measured during monthly sampling were good to fair. Dissolved oxygen readings made at the continuous recording station ranged from 2.4 in September to 9.6 mg/L in January. Mean monthly dissolved oxygen concentrations ranged from 4.5 in August to 8.8 mg/L in January. Mean daily dissolved oxygen levels commonly fell below 5 mg/L in the vicinity of this site between April and November. Water clarity conditions were good to fair on all monthly sampling dates during 2011. Turbidity readings made at the continuous recording station ranged from near 0 NTUs in the winter and mid-summer months to 687 NTUs during June. Mean monthly turbidity levels ranged from 5.3 NTUs in January to 39.1 NTUs in September. The highest daily mean turbidity levels tended to occur in spring and late fall. Salinity readings ranged from 30.5 parts per thousand (ppt) in March to 38.2 ppt in June. Mean monthly readings ranged from 31.1 ppt for the month of April to 36.3 ppt during June. The highest salinity levels were measured during the summer whereas the lowest levels were measured in early spring. pH values ranged between 7.0 and 8.4 throughout the year with the lowest pH conditions occurring episodically throughout the summer months. Mean monthly pH values fluctuated from 7.3 in September to 8.1 in January.
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Lu, Shuai, Ruisheng Diao, Nader A. Samaan, and Pavel V. Etingov. Capacity Value of PV and Wind Generation in the NV Energy System. Office of Scientific and Technical Information (OSTI), 2014. http://dx.doi.org/10.2172/1060671.
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Wright, Wendy, M. Gregory, and Aaron Rinehart. Fixed-station water quality monitoring at Fort Pulaski National Monument: 2011 data summary. National Park Service, 2012. https://doi.org/10.36967/2190461.
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In 2006 the National Park Service (NPS) Southeast Coast Network (SECN) Inventory and Monitoring Program began collecting water-quality data in the estuarine waters near Fort Pulaski National Monument (FOPU) as part the NPS Vital Signs monitoring program. The continuous monitoring data station is approximately 1.5 kilometers south of the Fort entrance at a dock on Lazaretto Creek just upstream of its confluence with the Savannah River. This station collects pH, dissolved oxygen, temperature, salinity, conductivity, turbidity and water level data every 30 minutes. Additional water quality measurements are made by SECN staff and include monthly measurements of water clarity conditions, nutrients, and chlorophyll a levels. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. This report contains data from January through December 2011. High levels of total dissolved phosphorus (TDP) were the most common cause of poor water-quality ratings across all sites and months based on monthly water quality samples. Total dissolved nitrogen (TDN) levels were all within the range considered good whereas chlorophyll levels rated as good to fair. Dissolved oxygen concentrations measured during monthly sampling were all good except for a single month (August) where levels indicated fair conditions. Dissolved oxygen readings made at the continuous recording station ranged from 2.1 mg/L in May to 10.9 mg/L in January. Mean monthly dissolved oxygen concentrations ranged from 9.7 mg/L in January to 4.8 mg/L in August. Mean daily dissolved oxygen levels commonly fell below 5 mg/L in the vicinity of this site between May and October. Water clarity conditions were good on all monthly sampling dates during 2011. Turbidity readings made at the continuous recording station ranged from near 0 NTUs in the late fall and winter months to 360 NTUs in February. The highest daily mean turbidity levels tended to occur in the late summer. Salinity readings ranged from 11.1 to 35.3 parts per thousand (ppt) with the lowest values occurring April to May and the highest salinity occurring during August. Mean monthly values ranged from 20.9 ppt in April to 28.2 ppt during August. pH values ranged between 7.1 and 8.7 throughout the year with the most acidic conditions occurring episodically throughout the summer months. Mean monthly pH values fluctuated from 7.6 to 8.6 trending to lower levels during the summer months.
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Gregory, M., Wendy Wright, and Aaron Rinehart. Fixed-station water quality monitoring at Fort Matanzas National Monument: 2011 data summary. National Park Service, 2012. https://doi.org/10.36967/2190459.
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In 2010 the National Park Service (NPS) Southeast Coast Network (SECN) Inventory and Monitoring Program began collecting water-quality data in the estuarine waters near Fort Matanzas National Monument (FOMA) as part the NPS Vital Signs monitoring program. The continuous-monitoring data station is located at the visitors center dock. This station collects pH, dissolved oxygen, temperature, salinity, specific conductance, turbidity and water-level data every 30 minutes. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. This report contains data from January through December 2011. Continuously-collected dissolved oxygen concentration data indicated good conditions, with the lowest monthly average levels occurring June through September. During these same months, there were several occurrences of the average daily value for dissolved oxygen dropping below 5 mg/L. Continuous turbidity data indicated turbidity levels below 50 NTUs for most of the year with levels between 50 and 150 NTUs common throughout the summer months. Salinity levels ranged from 31.94 to 37.78 parts per thousand (ppt) throughout the year, with monthly averages ranging from 32.69 in December to 36.7 in July. Mean monthly pH values ranged between 7.4 and 8.6.
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Gregory, M., Aaron Rinehart, and Wendy Wright. Fixed-station water-quality monitoring at Fort Pulaski National Monument: 2012 data summary. National Park Service, 2013. https://doi.org/10.36967/2195213.
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In 2006 the National Park Service (NPS) Southeast Coast Network (SECN) Inventory and Monitoring Program began collecting water-quality data in the estuarine waters near Fort Pulaski National Monument (FOPU) as part the NPS Vital Signs monitoring program. The continuous monitoring data station is approximately 1.5 kilometers south of the Fort entrance at a dock on Lazaretto Creek just upstream of its confluence with the Savannah River. This station collects pH, dissolved oxygen, water temperature, salinity, specific conductance, turbidity and water level data every 30 minutes. Additional water-quality measurements are made by SECN staff and include monthly measurements of water-clarity conditions, nutrients, and chlorophyll a levels. Methods used are adapted from the water-quality monitoring program established by the National Estuarine Research Reserve Program. The Fort Pulaski National Monument fixed-station water-quality monitoring site is part of the SECN estuarine water-quality monitoring program, which routinely collects data in the vicinity of seven coastal parks located along the southeastern U.S. coast. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. Summary data are presented in annual data reports published by the SECN. Findings for 2012 are as follows: Orthophosphate (DIP) levels were fair in August and November, while dissolved inorganic nitrogen levels were good in August and fair in November. Chlorophyll a levels rated as good in October and November and fair from June to September and in December. Dissolved oxygen concentrations measured during monthly sampling were good throughout the year. Dissolved oxygen readings made at the continuous recording station ranged from 2.63 mg/L in October to 9.57 mg/L in January. Mean monthly dissolved oxygen concentrations ranged from 5.1 mg/L in August to 8.9 mg/L in January. Mean daily dissolved oxygen levels commonly fell below 5 mg/L in the vicinity of this site between late July and October. Monthly water-clarity measurements were fair to good, with February, June and December reported as fair during 2012. Turbidity readings made at the continuous recording station ranged from near 0 NTUs in January to 701.7 NTUs in July. The highest monthly mean turbidity levels occurred in September (32.1 NTUs). Daily average turbidity levels were generally between 15 to 30 NTUs and rarely exceeded 40 NTUs. Mean monthly salinity values ranged from 25.1 ppt in March to 27.8 ppt during August. Individual salinity readings ranged from 17.3 parts per thousand (ppt) in June to 37.9 ppt in April. pH values ranged between 7.3 and 8.7 throughout the year with the most acidic conditions occurring episodically throughout the summer months. Mean monthly pH values fluctuated from 7.7 to 8.3 trending to lower levels during the late spring and early summer months. In 2012, roughly 10% of data were excluded from analysis because they were considered anomalous. Anomalous data during 2012 was most commonly associated with problems with dissolved oxygen and turbidity for a variety of reasons, primarily due to unknown sonde malfunctions or poor calibration data.
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Wright, Wendy, and M. Gregory. Fixed-station water-quality monitoring at Canaveral National Seashore: 2005 to 2009 Data Summary. National Park Service, 2013. https://doi.org/10.36967/2195998.
Full textAbstract:
In 2005 the National Park Service (NPS) Southeast Coast Network (SECN) began collecting water-quality data in the estuarine waters of Canaveral National Seashore as part the NPS Vital Signs monitoring program. The scope of the monitoring program includes Mosquito Lagoon and is comprised of continuous water-quality monitoring conducted by the SECN at one site and is augmented with monthly data collected at five stations by St. Johns River Water Management District (SJRWMD). The continuous-monitoring data station is located at the Canaveral National Seashore visitor center dock and collects pH, dissolved oxygen, temperature, salinity, turbidity and water-level data every 30 minutes. The five stations located throughout Mosquito Lagoon are sampled by Volusia County for the SJRWMD as part of the District’s Indian River Lagoon Water-Quality Monitoring Network; data at these five stations include monthly measurements of water-clarity conditions, nutrients, and chlorophyll a levels. Both the SECN and the SJRWMD programs use methods adapted from, or compatible with, the water-quality monitoring program established by the National Estuarine Research Reserve Program. The Canaveral National Seashore fixed-station water-quality monitoring site is part of the SECN estuarine water- and sediment-quality monitoring efforts, which routinely collects data in the vicinity of seven park units along the southeastern U.S. coast. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. This report only addresses the continuous data collected at one site at the Canaveral National Seashore Visitors Center. Mean monthly temperatures ranged from 16.6 °C in January and February of 2009 to 31.4 °C in August 2007. Highest water temperatures at CANA were typically observed during the late summer months of July and August with the coolest temperatures in January and February. Mean monthly salinity values averaged 35.5 ppt for this period and ranged from 27.6 ppt in June 2009 to 44.0 ppt in June 2008. Typically, lower salt concentrations were common in the winter and higher during the summer months. Rainfall events, tropical storms, and periods of drought influence salinities. Mean monthly dissolved oxygen levels ranged from 3.8 mg/L in June 2007 to 8.1 mg/L during January 2008. Mean monthly dissolved oxygen levels were typically lowest from June to October. Mean daily dissolved oxygen levels occasionally dropped below 3 mg/L during summer 2007 and fall 2009. Mean monthly pH values averaged 8.01 during this period. Almost all daily average values were between 7.5 and 8.5 except for several days during August when pH values briefly dropped below 7.0. Mean monthly turbidity ranged from 1.6 NTU in January 2008 to 34 NTUs in June 2008. Mean monthly average turbidity level for the period was 11.4 NTUs; however, mean daily turbidity values were highly variable. Water depth at the sampling site varied by 0.5 meters during the period of monitoring. From July 2005 until April 2007 and during July 2007all data collected were flagged due to lack of proper calibration procedures and instrument failures and are not shown in this report. Excluding this period, the average percentage of valid data (all parameters) collected monthly ranged from 14 % to 100 %. During this same period approximately 83 % of all data collected at this site is available for use.
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Borgwardt, Stefan, Ismail Ilkan Ceylan, and Thomas Lukasiewicz. Ontology-Mediated Queries for Probabilistic Databases. Technische Universität Dresden, 2017. http://dx.doi.org/10.25368/2023.218.
Full textAbstract:
Probabilistic databases (PDBs) are usually incomplete, e.g., contain only the facts that have been extracted from the Web with high confidence. However, missing facts are often treated as being false, which leads to unintuitive results when querying PDBs. Recently, open-world probabilistic databases (OpenPDBs) were proposed to address this issue by allowing probabilities of unknown facts to take any value from a fixed probability interval. In this paper, we extend OpenPDBs by Datalog± ontologies, under which both upper and lower probabilities of queries become even more informative, enabling us to distinguish queries that were indistinguishable before. We show that the dichotomy between P and PP in (Open)PDBs can be lifted to the case of first-order rewritable positive programs (without negative constraints); and that the problem can become NP^PP-complete, once negative constraints are allowed. We also propose an approximating semantics that circumvents the increase in complexity caused by negative constraints.
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Wright, Wendy, M. Gregory, and Aaron Rinehart. Fixed-station water quality monitoring at Canaveral National Seashore: 2011 data summary. National Park Service, 2012. https://doi.org/10.36967/2190431.
Full textAbstract:
In 2007 the National Park Service (NPS) Southeast Coast Network (SECN) began collecting water quality data in the estuarine waters of Canaveral National Seashore as part the NPS Vital Signs monitoring program. The scope of the monitoring program includes Mosquito Lagoon and is comprised of continuous water-quality monitoring conducted by the SECN at one site and is augmented with monthly data collected at five stations by St. Johns River Water Management District (SJRWMD). This report includes data from January through December, 2011. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. High levels of total dissolved nitrogen (TDN) were the most common cause of poor water-quality ratings across all sites and months. Higher concentrations of nutrients and chlorophyll a were most commonly observed during the late spring and summer months at all sites. Dissolved oxygen concentrations measured during monthly sampling were all rated good although continuous data indicated a period between June and September when mean daily values commonly dropped below 5 mg/L. Mean daily values observed during these periods were primarily due to low dissolved oxygen levels during the night and early morning. Water clarity conditions ranged from poor to good across all sites with all of the poor observations occurring during late summer and fall. Poor and fair water clarity conditions tended to occur during periods with elevated nutrients and chlorophyll a levels. Mean daily turbidity readings made at the continuous recording station were less than 15 nephelometric turbidity units (NTUs). Salinity ranged from 27 to 44 parts per thousand (ppt) with the higher values occurring during the summer months. pH values ranged between 7.54 and 8.75 throughout the year with the most acidic conditions occurring episodically throughout the summer months.
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Rinehart, Aaron, M. Gregory, and Wendy Wright. Fixed-station water-quality monitoring at Cape Lookout National Seashore: 2012 data summary. National Park Service, 2013. https://doi.org/10.36967/2195313.
Full textAbstract:
In 2007, the National Park Service (NPS) Southeast Coast Network (SECN) Inventory and Monitoring Program began a partnership with the North Carolina National Estuarine Research Reserve (NCNERR) to collect water-quality data in the estuarine waters near Cape Lookout National Seashore (CALO). Two continuous-monitoring stations have been operational since 2008 in the Shackleford Banks Dock and in the Middle Marshes area. Methods used are adapted from the water-quality monitoring program established by the National Estuarine Research Reserve Program. The Cape Lookout National Seashore fixed-station water-quality monitoring sites are part of the SECN estuarine water-quality monitoring program, which routinely collects data in the vicinity of seven coastal parks along the southeastern U.S. coast. Salinity, dissolved oxygen, pH, turbidity, water temperature, specific conductance (to compute salinity), and water-level data were collected at two stations at CALO. Monthly measurements of water clarity conditions, and the collection of a grab sample analyzed for total dissolved phosphorus, dissolved inorganic phosphorus, total dissolved nitrogen, dissolved inorganic nitrogen, and chlorophyll a levels were also made at both sites. Discrete water-quality samples collected monthly at both sites indicated good conditions with respect to water clarity with one fair reading in February at CALOshak. Chlorophyll a, readings were also good throughout the year, with one fair reading in October at CALOshak, where data were available. Dissolved inorganic nitrogen and phosphorus levels were good at CALOshak. Orthophosphate levels were slightly elevated at CALOshak2 during November. Salinity concentrations followed the same general pattern throughout the year at both sites, generally declining after periods of high rainfall and runoff. Individual and monthly mean low readings at CALOshak occurred in November at 25.82 and 39.9 ppt, respectively, compared to individual and monthly mean lows at CALOshak2 in September (22.20 and 27.8 ppt respectively). Conversely, individual and monthly high readings at CALOshak were 36.98 and 36.2 ppt respectively in May, whereas individual and monthly high readings at CALOshak2 were 38.41 and 35.6 ppt respectively in July. Mean monthly dissolved oxygen levels were similar between sites ranging from 5.4 to 8.8 mg/L at CALOshak and from 6.1 to 9.0 mg/L at CALOshak2. The season lows at each site occurred during the summer months; however, individual readings below 5.0 mg/L were common at CALOshak2 occurring between March and October. Mean daily dissolved oxygen (DO) levels were never below 5.0 mg/L at CALOshak2, but were below 5.0 mg/L at CALOshak for six days in August. Monthly mean pH values were similar between sites ranging from 8.0 to 8.1 at CALOshak and from 7.9 to 8.1 at CALOshak2. Average monthly turbidity at both CALOshak and CALOshak2 never exceeded 8.0NTUs. Mean daily turbidity values at CALOshak did not exceed 36 NTUs, and CALOshak2 values did not exceed 26 NTUs. Water temperatures at CALOshak2 were more variable than those at CALOshak. Individual readings at CALOshak2 ranged from 3.1°C (37.5°F) in January to 33.5°C (92.2°F) in August, while temperatures at CALOshak ranged from 7.3°C (45.1°F) in January to 30.8°C (87.5°F) in August. Monthly mean water temperatures ranged from 11.0°C (51.8°F) to 28.8°C (83.84°F) from January to July at CALOshak2, versus 11.3°C (52.34°F) to 28.2°C (82.76°F) from January to July and August at CALOshak.