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1
Минаев, Владимир Александрович, Алена Дмитриевна Реброва, and Александр Викторович Симонов. "DETECTION DESTRUCTIVE CONTENT IN SOCIAL MEDIA BASED ON MACHINE LEARNING MODELS." ИНФОРМАЦИЯ И БЕЗОПАСНОСТЬ, no. 1(-) (April 9, 2021): 7–20. http://dx.doi.org/10.36622/vstu.2021.24.1.001.
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В статье обсуждаются модели классификации текстового контента и методы его предварительной обработки с целью выявления деструктивных воздействий в социальных медиа. Показано, что основным источником деструктивного контента выступает профиль пользователей, характеризующийся набором личным данных, содержанием публикаций, параметрами сообщества, аккаунтов сети, сообщений и чатов. Говорится об актуальности автоматизированного сбора и анализа данных с помощью моделей прецедентного и дедуктивного обучения. Рассматриваются их основные разновидности и задачи, решаемые на их основе, включающие прогнозирование и типологизацию в аспекте деструктивного содержания текстов, снижение размерности признаков их описания. Исследованы и применены основные методы векторизации текстов: Bag of Words, TF_IDF, Word2vec. На практических корпусах текстов из социальной сети ВКонтакте решены задачи выявления деструктивного контента, связанного с радикальным исламом. Показано, что с помощью примененных моделей и методов все тексты, включающие деструктивный контент, классифицированы верно. Наиболее высокую точность (0,97) при решении задачи распознавания деструктивного контента дает системная интеграция алгоритма векторизации Bag of Words, метода главных компонент для снижения пространства признаков описания текстов и логистической регрессии или случайного леса как моделей обучения. Сделан вывод, что наборы данных, имеющие связь с исламским радикализмом, характеризуются достаточно четкими признаками, которые хорошо вычисляемы с помощью современных моделей, методов и алгоритмов, и могут эффективно применяться для автоматизированной классификации текстовых массивов с целью выявления их деструктивной направленности. Развитие направления, представленного в статье, связано с увеличением исследуемых корпусов документов, более детальным анализом текстов на основе сложных моделей распознавания латентной экстремистской пропаганды, в том числе - представленной в фото, аудио- и видеоформатах. The article discusses models of classification of text content and methods of its pre-processing in order to identify destructive influences in social media. It is shown that the main source of destructive content is the user profile, which is characterized by a set of personal data, the content of publications, community parameters, network accounts, messages and chats. Automated data collection and analysis using case-based and deductive learning models is discussed. We consider their main varieties and the tasks solved on their basis, including forecasting and typology in the aspect of the destructive content of texts, reducing the dimension of the features of their description. The main methods of text vectorization are investigated and applied: Bag of Words, TF_IDF, Word2vec. The tasks of identifying destructive content related to Islamic radicalism are solved on the practical corpus of texts from the social network VKontakte. It is shown that using the applied models and methods, all texts that include destructive content are classified correctly. The highest accuracy (0.97) in solving the problem of recognizing destructive content is provided by the system integration of the Bag of Words vectorization algorithm, the principal component method for reducing the feature space of text descriptions, and logistic regression or random forest as learning models. It is concluded that the data sets associated with Islamic radicalism are characterized by sufficiently clear features that are well calculated using modern models, methods and algorithms, and can be effectively used for automated classification of text arrays in order to identify their destructive orientation. The development of the direction presented in the article is associated with an increase in the studied corpus of documents, a more detailed analysis of texts based on complex models for recognizing latent extremist propaganda, including those presented in photo, audio and video formats.
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Никитина, L. Nikitina, Коноплева, A. Konopleva, Чудина-Шмидт, and N. Chudina-Shmidt. "The Analysis of Socio-Cultural and Psychological Prerequisites of the Development of Extremism in the Crimean Federal District." Socio-Humanitarian Research and Technology 5, no. 3 (September 19, 2016): 53–60. http://dx.doi.org/10.12737/20938.
Full textAbstract:
One of the most relevant topics for today´s research is the
problem of the rapid development of extremism. Because of the abstraction
and inaccuracies represented by the law, the fight against
extremist tendencies continues to be difficult. A kind of indicator for
the detection of possible threats from the point of view of radical
ideas is a transitional period. Changes in the geopolitical and socioeconomic
conditions. Lead to the an exacerbation of pre-existing
differences, and thus become catalysts of destructive processes. This
is precisely the situation that exists in the Crimean Federal District
today. The work is devoted to the study of social and psychological
preconditions for the emergence of extremism in the Crimean Federal
District. The data used in the research are obtained as a result of a poll
of the population of the region. The data of the survey has been assessed
in terms of psychological and social factors. The novelty of the research
lies in the implementation of a systematic approach to the problem of
the emergence of extremism and attempts to identify its regional
features.
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Mussiraliyeva, Shynar, Batyrkhan Omarov, Paul Yoo, and Milana Bolatbek. "Applying Machine Learning Techniques for Religious Extremism Detection on Online User Contents." Computers, Materials & Continua 70, no. 1 (2022): 915–34. http://dx.doi.org/10.32604/cmc.2022.019189.
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Kutuzov, Aleksey V. "OPERATIVE-SEARCH MONITORING THE INTERNET AS AN ELEMENT OF COUNTERING CRIMES OF EXTREMIST DIRECTION." Vestnik of Kostroma State University, no. 2 (2020): 235–41. http://dx.doi.org/10.34216/1998-0817-2020-26-2-235-241.
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The article substantiates the need to use Internet monitoring as a priority source of information in countering extremism. Various approaches to understanding the defi nition of the category of «operational search», «law enforcement» monitoring of the Internet are analysed, the theoretical development of the implementation of this category in the science of operational search is investigated. The goals and subjects of law enforcement monitoring are identifi ed. The main attention is paid to the legal basis for the use of Internet monitoring in the detection and investigation of extremist crimes. In the course of the study hermeneutic, formal-logical, logical-legal and comparative-legal methods were employed, which were used both individually and collectively in the analysis of legal norms, achievements of science and practice, and development of proposals to refi ne the conduct of operational-search measures on the Internet when solving extremist crimes. The author’s defi nition of «operational-search monitoring» of the Internet is provided. Proposals have been made to improve the activities of police units when conducting monitoring of the Internet in the context of the search for relevant information to the disclosure and investigation of crimes of that category.
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Zhang, Xuebin, Gabriele Hegerl, Francis W. Zwiers, and Jesse Kenyon. "Avoiding Inhomogeneity in Percentile-Based Indices of Temperature Extremes." Journal of Climate 18, no. 11 (June 1, 2005): 1641–51. http://dx.doi.org/10.1175/jcli3366.1.
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Abstract Using a Monte Carlo simulation, it is demonstrated that percentile-based temperature indices computed for climate change detection and monitoring may contain artificial discontinuities at the beginning and end of the period that is used for calculating the percentiles (base period). This would make these exceedance frequency time series unsuitable for monitoring and detecting climate change. The problem occurs because the threshold calculated in the base period is affected by sampling error. On average, this error leads to overestimated exceedance rates outside the base period. A bootstrap resampling procedure is proposed to estimate exceedance frequencies during the base period. The procedure effectively removes the inhomogeneity.
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van de Weert, Annemarie, and Quirine A. M. Eijkman. "Early detection of extremism? The local security professional on assessment of potential threats posed by youth." Crime, Law and Social Change 73, no. 5 (December 10, 2019): 491–507. http://dx.doi.org/10.1007/s10611-019-09877-y.
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AbstractFrontline professionals such as social workers and civil servants play a crucial role in countering violent extremism. Because of their direct contact with society, firstliners are tasked with detecting individuals that may threaten national security and the democratic rule of law. Preliminary screening takes place during the pre-crime phase. However, without clear evidence or concrete indicators of unlawful action or physical violence, it is challenging to determine when someone poses a threat. There are no set patterns that can be used to identify cognitive radicalization processes that will result in violent extremism. Furthermore, prevention targets ideas and ideologies with no clear framework for assessing terrorism-risk. This article examines how civil servants responsible for public order, security and safety deal with their mandate to engage in early detection, and discusses the side effects that accompany this practice. Based on open-interviews with fifteen local security professionals in the Netherlands, we focus here on the risk assessments made by these professionals. To understand their performance, we used the following two research questions: First, what criteria do local security professionals use to determine whether or not someone forms a potential risk? Second, how do local security professionals substantiate their assessments of the radicalization processes that will develop into violent extremism? We conclude that such initial risk weightings rely strongly on ‘gut feelings’ or intuition. We conclude that this subjectivity may lead to prejudice and/or administrative arbitrariness in relation to preliminary risk assessment of particular youth.
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Lamim Filho, Paulo Cezar Monteiro, Fabiano Bianchini Batista, Robson Pederiva, and Vinicius Augusto Diniz Silva. "Electrical fault diagnosis in induction motors using local extremes analysis." Journal of Quality in Maintenance Engineering 22, no. 3 (August 8, 2016): 321–32. http://dx.doi.org/10.1108/jqme-07-2015-0026.
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Purpose – The purpose of this paper is to introduce an algorithm based only on local extreme analysis of a time sequence to further the detection and diagnosis of inter-turn short circuits and unbalanced voltage supply using vibration signals. Design/methodology/approach – The upper and lower extreme envelopes from a modulated and oscillatory time sequence present a particular characteristic being of, theoretically, symmetrical versions with regard to amplitude reflection around the time axis. Thus, one may say that they carry the same characteristics in terms of waveforms and, consequently, frequency content. These envelopes can easily be built by an interpolation process of the local extremes, maximums and minimums, from the original time sequence. Similar to modulator signals, they contain more detailed and useful information about the required electrical fault frequencies. Findings – Results show the efficiency of the proposed algorithm and its relevance to detecting and diagnosing faults in induction motors with the advantage of being a technique that is easy to implement in any computational code. Practical implications – A laboratory investigation carried out through an experimental setup for the study of faults, mainly related to the stator winding inter-turn short circuit and voltage phase unbalance, is presented. Originality/value – The main contribution of the work is the presentation of an alternative tool to demodulate signals which may be used in real applications like the detection of faults in three-phase induction machines.
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Varga-Fekete, Tímea, Katalin Felvinczi, Emese Kun-Bálint, A. Puskás, E. Nagy, and Z. Brassai. "Accuracy of Ankle-Brachial Index Measurements in Evaluation of Critical Leg Ischemia." Acta Medica Marisiensis 59, no. 2 (April 1, 2013): 85–87. http://dx.doi.org/10.2478/amma-2013-0019.
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Abstract Aims: The ankle-brachial index is an efficient tool for objectively documenting the presence of lower extremity peripheral artery disease. However, its applicability for detection of critical leg ischemia is still controversial. We proposed to determine the diagnostic accuracy of the ankle-brachial index for critical ischemia. Materials and methods: Systolic blood pressure measurements for calculation of the ankle-brachial index were obtained in 90 patients with peripheral artery disease. Ankle-brachial index was computed in 3 different ways (using the lowest ankle pressure, the highest ankle pressure, and the mean of the ankle pressures), sensibility, specificity, positive and negative predictive value and overall accuracy for detecting critical ischemia were determined for each method. A value ≤ 0.4 was taken as cut-off point for critical leg ischemia. Prevalence of coronary and cerebrovascular atherosclerosis and conventional risk factors were also noted. Results: Using the lowest ankle pressure for computing ankle-brachial index provided higher sensitivity, and lower specificity for detecting critical leg ischemia, using the highest pressure was less sensitive, but more specific, and the mean pressure index gave intermediate results. Overall accuracy was highest for the latest method. The prevalence of generalized atherosclerosis was high in peripheral artery disease, but we found no significant difference between the intermittent claudication and the critical ischemia group. Conclusion: Ankle-brachial index measurements, regardless of the method used for calculation, cannot identify or rule out reliably critical leg ischemia. Peripheral artery disease confers an increased risk of cardiovascular disease regardless of symptom status or lower extremity perfusion severity.
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Ilyevsky, V. I. "Recursive Formula for the Random String Word Detection Probability, Overlaps and Probability Extremes." Journal of Mathematics Research 11, no. 2 (March 24, 2019): 171. http://dx.doi.org/10.5539/jmr.v11n2p171.
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In this paper, for the first time ever, the properties of the word detection probability in a random string have been investigated. The formerly known methods led to numerical evaluation of the researched probabilities only. The present work derives the simplest algorithm for calculation of the word’s at least once detection probability in a random string. A recursive formula that considers the overlap capability has been deduced for the probability under study. This formula is being used for the proposition on comparison of the word detection probabilities in a random string for the words with different periods. The result allows determining the structure of words that have maximum and minimum detection probabilities. In particular, words having equal number of alphabetic characters have been studied. It has been established, that for the words in question detection probability is minimal for the ideally symmetrical words that have irreducible period - and maximal for the words devoid of the overlap feature. These results will be useful for molecular genetics, as well as for students studying discrete mathematics, probability theory and molecular biology.
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Celebi, Savas, Ozlem Ozcan Celebi, Serkan Çetin, Elif Hande Ozcan Cetin, Erdem Diker, Sinan Aydogdu, Berkten Berkalp, and Basri Amasyalı. "Invasive screening for lower extremity peripheral artery disease: Killing two birds with one stone?" Vascular 28, no. 2 (October 11, 2019): 196–202. http://dx.doi.org/10.1177/1708538119881592.
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Objectives There is substantial evidence that the majority of cases of lower extremity peripheral artery disease are undetected. As a result, there is great interest in the detection of lower extremity peripheral artery disease through routine screening. However, routine screening of lower extremity peripheral artery disease is still debated. Methods In our cross-sectional study, we included 200 consecutive patients with symptoms suggestive of angina who were undergoing coronary angiography. Irrespective of intermittent claudication, we subsequently performed peripheral angiography to detect lower extremity peripheral artery disease. The predictors of lower extremity peripheral artery disease were analyzed, and the diagnostic utility of these predictors and their combinations were determined. Additionally, the determinants of the amount of radio-opaque material used and peripheral fluoroscopy time were investigated. Results The overall prevalence of lower extremity peripheral disease was 16%. Being older than 65 years, having coronary artery disease and smoking history remained significant predictors after adjusting for other well-known parameters. Having the combination of age ≥65 and smoking was associated with a positive predictive value of 50% (likelihood ratio 5.06), and having all of the predictors was associated with a positive predictive value of 100% (likelihood ratio >1000). Conclusions Routine screening for lower extremity peripheral disease patients undergoing coronary angiography may be useful in selected patients.
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Nielsen, K. Rue, H. Klyver, A. Hougaard Chakera, L. Nedergaard, B. Hesse, and M. Bachmann Nielsen. "Sentinel node detection in melanomas using contrast-enhanced ultrasound." Acta Radiologica 50, no. 4 (May 2009): 412–17. http://dx.doi.org/10.1080/02841850902824934.
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Background: Sentinel node (SN) biopsy has proven to be a useful clinical method based on the combination of radionuclide tracer principles and the dye technique. Contrast-enhanced ultrasound (CEUS) has been used successfully for detection of SN in animals, but the use of CEUS has not been reported in humans. Purpose: To investigate the possible use of CEUS in detecting SN in patients with malignant melanomas (MM), and to improve the method by using different concentrations of contrast agent and various positions of the extremity. Material and Methods: Ten patients with MM on an extremity and one healthy volunteer were included. One milliliter of a contrast agent (Sonovue; Bracco, Milan, Italy) was injected subcutaneously on both sides of the scar from the excised tumor. Contrast-enhanced lymph channels and lymph nodes (LNs) were searched for using low-mechanical-index CEUS and by stimulated acoustic emission. Afterward, lymphoscintigraphy was performed and the patient operated. During surgery, the SNs were located via scintigraphic findings, gamma-probe signals, and blue-dye visualization of lymph channels and LNs. Before the human study, a study of 10 mice was performed to exclude possible tissue damage, as the contrast agent was not registered for subcutaneous administration. Results: In one patient, two contrast-enhanced inguinal LNs were visualized by CEUS, corresponding to two inguinal SNs found by scintigraphic imaging. No contrast-enhanced lymph channels or LNs were visualized in any other patients or in the volunteer. No tissue damage was observed in the 10 mice. Conclusion: This study does not support the use of CEUS for detection of SNs in humans. However, the application of CEUS for the investigation of SNs is still not fully explored in humans, and an alternative setup and/or contrast agent might provide better results.
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Nazia Fathima, S. M., R. Tamilselvi, and M. Parisa Beham. "XSITRAY: A Database for the Detection of Osteoporosis Condition." Biomedical and Pharmacology Journal 12, no. 1 (March 19, 2018): 267–71. http://dx.doi.org/10.13005/bpj/1637.
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In the medical era, health of a bone is accessed by the bone mineral density (BMD) test. Bone fracture risk in the humans are estimated or evaluated by the BMD test. The test statement recognizes the presence of signs of presence of the frequent occurring disease in the bone called as osteoporosis. In the earlier stage, the challenge in the BMD measurement is that traditional x-rays are used with a step wedge made from an aluminum or ivory phantom. At each step of the phantom with the known densities, bone content present is intended by a illustration assessment of the density present in the bone. Effectiveness in the value and feasibility in the X-rays compared to cutting-edge methods divulge the potential for novel medical relevance among the investigators. So it is obligatory to enclose a customary database in X-Ray images for the young bud researchers to capture up the dealings to the advance stage by accurate examination of the medical results of the images. The projected X-Ray database is termed XSITRAY, characterizes an early attempt to offer a group of X-Ray images of Spine, Femur, Clavicle, Extremity & Ankle, Extremity & Hand and Knee bones. The details such as age, gender and unique Id of the patient are interpreted in the database.
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Lavrentiev, Alexei M., Margarita I. Suvorova (Ananyeva), Alina I. Fokina, and Andrey M. Chepovskiy. "A new toolkit for natural text processing with the TXM platform and its application to a corpus for analysis of texts propagating extremist views." NSU Vestnik. Series: Linguistics and Intercultural Communication 16, no. 3 (2018): 19–31. http://dx.doi.org/10.25205/1818-7935-2018-16-3-19-31.
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TXM platform provides a wide range of corpus analysis tools including correspondence analysis, clustering, lexical table construction, and parametrized subcorpus selection. The default structural unit of analysis for TXM is a token. The only TXM extension available by default is TreeTagger which performs automated morphological analysis and lemmatization during the corpus import process. However, it is possible to supply each token with a number of features enabling a more advanced text analysis. In this work we present a number of tools developed for even a more extensive, complex and flexible corpus analysis with TXM relying both on the tools previously developed by our team and on publicly available software libraries. We focus in particular on a stemming technique that uses a word structural pattern method and on noun phrase recognition that together make it possible to perform more sophisticated and powerful queries and analyses of the corpus not limited to word forms. The structural pattern stemming method is based on a set of specific language rules that allow separating a word stem from all affixes. The recognition of noun phrases is based on rules allowing the detection of subordination and coordination relations among nouns. These extensions result in the improvement of performance of statistical tools used by TXM, such as specificity scores and correspondence analysis. The new set of tools has been tested on a corpus including texts marked as «extremist» by experts along with «neutral» texts in similar domains. The corpus of approximately 900,000 words is divided into eight subcorpora: neutral texts oppose seven thematic subcorpora considered as extremist (namely aggressive, fascist, ideological, nationalistic, religious, separatist, and terroristic). The specificity analysis detects the words (or other structural units) that are significantly more or less frequent in a given subcorpus compared to the entire corpus. The specificity score for selected units can be compared across all the subcorpora in order to verify their difference or similarity. The correspondence analysis produces a chart where the subcorpora are represented as points in a twodimensional space based on their similarity as to the frequency of selected units. All tests demonstrated a significant difference between neutral texts, on one side, and marked, on the other. Two «extremist» subcorpora, religious and ideological, demonstrated similar results and can probably be merged. These facts encourage further research on fully automatic or computer-aided expert recognition of extremist texts.
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Pangeni, Roshan, Ping Han, Feng Pan, Laxmi Pangeni Lamsal, Zhen Zhang, Jie Yu, and Rajiv Rizal. "Assessment of occlusive disease of lower extremity arteries on the basis of anatomic region: Value of 128-slice multidetector CT angiography in comparison with digital subtraction angiography." Journal of College of Medical Sciences-Nepal 12, no. 4 (January 19, 2017): 179–86. http://dx.doi.org/10.3126/jcmsn.v12i4.16416.
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Background & Objectives: The Previous studies of multidetector CT (MDCT) of the lower extremities for the detection of peripheral vascular disease showed high diagnostic accuracy but were performed with older generation systems. Our study aimed at assessing the diagnostic value of 128 MDCTA compared with that of digital subtraction angiography (DSA) in the grading of focal arterial disease of lower extremity arteries on the basis of anatomic regions.Materials & Methods: Forty-two patients with peripheral arterial occlusive diseases underwent both MDCTA and DSA. Lower extremity arteries depicted at MDCTA and DSA were graded separately for the degree of stenosis into 3 anatomic regions and 33 segments. Grading by MDCTA and DSA was done independently. Homogeneity analysis was used between MDCTA and DSA measurements in each patient. The sensitivity, specificity, positive predictive value and negative predictive value for detection of stenotic lesions were calculated for all anatomic regions, with findings at DSA used as the reference standard. Results: No statistically significant difference (P>.05) between DSA and MDCTA was present in Aorto-iliac and poplitiofemoral regions while there was statistically significant difference (P<.05) in the infrapopliteal region. The Sensitivity, Specificity, Positive Predictive Value and Negative Predictive Value based on a reading of MDCTA were 84.3%, 93.8%, 89.4% and 90.6% for aorto-iliac 86.6%, 94.7%, 84.1% and 94.7% for poplitiofemoral and 95.7%, 86.1%, 85.6% and 95.9% for infra-popliteal region respectively.Conclusion: MDCTA is excellent alternative in diagnosing lower extremity arterial occlusive diseases above the knee. DSA remains better on illustrating distal runoff vessels.
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Berdnikova, T. V. "The Problem of Detecting Incitement in Extremist Content (Using Examples from the Internet)." Theory and Practice of Forensic Science 14, no. 3 (October 23, 2019): 34–39. http://dx.doi.org/10.30764/1819-2785-2019-14-3-34-39.
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The article considers the characteristics of targeting when identifying the signs of incitement in extremist materials: in texts, commentaries to articles, videos, audios etc. on the Internet. The methods of linguistic analysis (lexical-semantic, stylistic analysis, semantic analysis, communicative-pragmatic analysis) were used in the study. As a result, the following forms of targeting expression in the aspect of linguistic signs of incitement were identified: 1) an appeal to a specific interlocutor (to a specific person, group of persons); 2) through the components of the communicative situation in general (focus on the mass, public addressee and even on the self which is transformed into a focus on the own group). Complicated cases of the implementation of the targeting category in texts with a pronounced or hidden language game are noted. The definition of the targeting category is shown to be an important component when identifying the linguistic signs of the “incitement” meaning, the speech (text) purpose depends on it. Targeting is closely related to the types of incitement: direct/indirect, explicit/implicit. To identify the linguistic features of the “incitement” meaning it is necessary to conduct a multidimensional analysis considering the general communicative situation, the category of targeting and its implementation in the statement.
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Dunkerley, David. "Sub-Daily Rainfall Intensity Extremes: Evaluating Suitable Indices at Australian Arid and Wet Tropical Observing Sites." Water 11, no. 12 (December 11, 2019): 2616. http://dx.doi.org/10.3390/w11122616.
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Rainfall intensity extremes are relevant to many aspects of climatology, climate change, and landsurface processes. Intensity is described and analysed using a diversity of approaches, reflecting its importance in these diverse areas. The characteristics of short-interval intensity extremes, such as the maximum 5-min intensity, are explored here. It is shown that such indices may have marked diurnal cycles, as well as seasonal variability. Some indices of intensity, such as the SDII (simple daily intensity index), provide too little information for application to landsurface processes. Upper percentiles of the intensity distribution, such as the 95th and 99th percentiles (Q95 and Q99) are used as indices of extreme intensity, but problematically are affected by changes in intensity below the nominated threshold, as well as above it, making the detection of secular change, and application to sites with contrasting rainfall character, challenging. For application to landsurface processes, a new index is introduced. This index (RQ95), is that intensity or rainfall rate above which 5% of the total rainfall is delivered. This index better reflects intense rainfall than does Q95 of even 5-min accumulation duration (AD) rainfall depths. Such an index is helpful for detecting secular change at an observing station, but, like Q95, remains susceptible to the effects of change elsewhere in the distribution of intensities. For understanding impacts of climate and climate change on landsurface processes, it is argued that more inclusive indices of intensity are required, including fixed intensity criteria.
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Needham, Terry. "Assessment of Lower Extremity Venous Valvular Insufficiency Examinations." Journal for Vascular Ultrasound 29, no. 3 (September 2005): 123–29. http://dx.doi.org/10.1177/154431670502900303.
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Usually, venous insufficiency affecting an extremity results from elevated pressure, whereas arterial insufficiency usually is caused by reduced pressure energy. Except when caused by arteriovenous fistulae, elevated venous pressures are caused by obstruction to outflow and/or by incompetence of the venous valves, particularly at popliteal level and in the calf perforator veins. In the lower extremity, such elevated venous pressures can result in chronic changes that cause symptoms and/or signs that range from “tired legs” to ulceration. Although mild venous hypertension may constitute only a relative inconvenience such as varicose veins, more severe cases can lead to debilitating ulceration that may demand a change in lifestyle. Assessing an extremity for venous valvular insufficiency means detecting venous reflux. This work describes the plethysmographic, continuous-wave Doppler, and duplex ultrasound imaging modalities that can be used for detecting venous reflux in the deep, superficial, and perforating veins. Although plethysmographic and continuous-wave Doppler modalities have been supplanted largely by duplex ultrasound imaging, they have been included for completeness because they can continue to fulfill a role in overall functional assessment. Whatever the testing modality used to assess venous reflux, it is essential to verify the patency of the deep veins before any intervention in the superficial venous system.
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Hulme, Mike. "Attributing weather extremes to ‘climate change’." Progress in Physical Geography: Earth and Environment 38, no. 4 (June 5, 2014): 499–511. http://dx.doi.org/10.1177/0309133314538644.
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Over the last 30 years, scientific research has increasingly implicated human activities in contemporary regional- to global-scale climatic change. Over the last decade, this research has extended to the detection of the fingerprint of human activities on individual extreme weather events. Is it possible to say that this or that weather extreme was ‘caused by’ human activities? Pursuing answers to this question raises many difficult philosophical, epistemological and political issues. In this progress report, I survey the nascent science of extreme weather event attribution by examining the field in four stages: motivations for extreme weather attribution, methods of attribution, some example case studies and the politics of weather event attribution. There remain outstanding political dangers and obstacles for extreme weather attribution if it is to be used, as some claim it can and should be, for guiding climate adaptation investments, for servicing the putative loss and damage agenda of the UN Framework Convention on Climate Change or for underpinning legal claims for liability for damages caused by extreme weather.
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Planken, R. N., T. Leiner, R. J. Nijenhuis, L. E. Duijm, P. W. Cuypers, P. Douwes-Draaijer, F. M. Van Der Sande, A. G. Kessels, and J. H. Tordoir. "Contrast-Enhanced Magnetic Resonance Angiography Findings Prior to Hemodialysis Vascular access Creation: A Prospective Analysis." Journal of Vascular Access 9, no. 4 (October 2008): 269–77. http://dx.doi.org/10.1177/112972980800900408.
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Purpose To determine prospectively the clinical value of contrast-enhanced magnetic resonance angiography (CE-MRA) for assessment of the arterial inflow and venous outflow prior to vascular access (VA) creation. Methods Seventy-three patients underwent duplex ultrasonography (DUS) and CE-MRA prior to VA creation for detection of stenoses and occlusions. Two observers read the CE-MRA images for determination of inter-observer agreement. A VA was considered functional if it could be used for successful two-needle hemodialysis therapy within 2 months after creation. Results CE-MRA detected 6 stenosed, 8 occluded arterial vessel segments and 12 stenosed and 41 occluded venous vessel segments in 70 patients. Inter-observer agreement for detection of upper extremity arterial and venous stenoses and occlusions with CE-MRA was substantial to almost perfect (kappa values 0.76–0.96). CE-MRA detected lesions, not detected by DUS, that were associated with VA early failure and non-maturation in 33% of patients (7/21). Accessory veins detected preoperatively were the cause of VA non-maturation in a substantial group of patients (47%: 7/15). Conclusion CE-MRA enables accurate detection of upper extremity arterial and venous stenosis and occlusions prior to VA creation. Preoperative CE-MRA identified arterial and venous stenoses, not detected by DUS that were associated with VA early failure and non-maturation. However, the use of gadolinium containing contrast media is currently contraindicated due the reported incidence of nephrogenic systemic fibrosis.
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ZHU, LIANQING, MINGLI DONG, WENCHANG ZHANG, ZHEHAI ZHOU, XIAOPING LOU, and WENCHANG ZHANG. "PRESSURE MONITORING OF MICRO-PIPETTING BASED ON ABSOLUTE DEGREE OF GREY COEFFICIENTS AND DOUBLE EXTREMES METHOD." Journal of Mechanics in Medicine and Biology 15, no. 06 (December 2015): 1540056. http://dx.doi.org/10.1142/s0219519415400564.
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Toward improving the real-time property and stability of the micro-pipetting process of an automatic enzyme-linked immunoassay analysis system, the fault detection of the process was studied by monitoring the pressure. A new method that combines the absolute degree of grey coefficients (ADGC) with the double extremes method (DEM) for monitoring pressure is proposed. The ADGC is used to demonstrate the variation of the pressure signal. In particular, the sectioning used is more flexible and is not constrained by the key timings of the micro-pipetting process. The data for a single point can be calculated in real time to obtain the double extremes (the extremes of the pressure and the first derivative) using the DEM. The DEM can therefore be performed without the need to reduce the sampling frequency, thereby guarantying the information integrity. By comparing the double extremes with the preset threshold, the fault types such as tip blockage, presence of air bubbles, and sample shortage can be distinguished. Moreover, a grey filtering technique based on the GM (1, 1) model is used to improve the stability of the pressure sensor output and significantly reduce the real-time computation requirements. Experiments were performed to verify the feasibility of the combined pressure monitoring method, and it was confirmed that it could be used to ensure real-time integrity of the information of the pressure curve. It can thus be confidently concluded that the method can be used to improve the accuracy and stability of monitoring the pressure of micro-pipetting.
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van Gerven, P., S. M. Rubinstein, C. Nederpelt, M. F. Termaat, P. Krijnen, M. W. van Tulder, and I. B. Schipper. "The value of radiography in the follow-up of extremity fractures: a systematic review." Archives of Orthopaedic and Trauma Surgery 138, no. 12 (August 14, 2018): 1659–69. http://dx.doi.org/10.1007/s00402-018-3021-y.
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Abstract Background The added value of routine radiography in the follow-up of extremity fractures is unclear. The aim of this systematic review was to create an overview of radiography use in extremity fracture care and the consequences of these radiographs for the treatment of patients with these fractures. Materials and methods Studies were included if they reported on the use of radiography in the follow-up of extremity fractures and on its influence on treatment strategy, clinical outcome, or complications. A comprehensive search of electronic databases (i.e., PubMed, Embase, and Cochrane) was performed to identify relevant studies. Methodological quality was assessed with the Newcastle–Ottawa scale for cohort studies. Level of evidence was assessed using GRADE. The search, quality appraisal, and data extraction were performed independently by two researchers. Results Eleven studies were included. All studies were retrospective cohorts. Of these, only two used a comparative design. Two of the included studies described fractures of both the upper and lower extremities, four studies concerned fractures of the lower extremity only, and five studies focused on fractures of the upper extremity. Pooling of data was not performed because of clinical heterogeneity. Eight studies reported on a change in treatment strategy related to radiography. Percentages ranged from 0 to 2.6%. The overall results indicated that radiographs in the follow-up of extremity fractures seldom alter treatment strategy, that the vast majority of follow-up radiographs are obtained without a clinical indication and that detection of a complication on a radiograph, in the absence of clinical symptoms, is unlikely. All included studies were regarded of a ‘very low’ level using GRADE. Conclusions Based on current literature, the added value of routine radiography in the follow-up of extremity fractures seems limited. Results, however, should be interpreted with care, considering that available evidence is of a low level.
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Yue, Chunfeng, Xichuan Lin, Ximing Zhang, Jing Qiu, and Hong Cheng. "Design and Performance Evaluation of a Wearable Sensing System for Lower-Limb Exoskeleton." Applied Bionics and Biomechanics 2018 (September 18, 2018): 1–9. http://dx.doi.org/10.1155/2018/8610458.
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Because the target users of the assistive-type lower extremity exoskeletons (ASLEEs) are those who suffer from lower limb disabilities, customized gait is adopted for the control of ASLEEs. However, the customized gait is unable to provide stable motion for variable terrain, for example, flat, uphill, downhill, and soft ground. The purpose of this paper is to realize gait detection and environment feature recognition for AIDER by developing a novel wearable sensing system. The wearable sensing system employs 7 force sensors as a sensing matrix to achieve high accuracy of ground reaction force detection. There is one more IMU sensor that is integrated into the structure to detect the angular velocity. By fusing force and angular velocity data, four typical terrain features can be recognized successfully, and the recognition rate can reach up to 93%.
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WANG, YAN-LIN, KE-YI WANG, WEN-YAN ZHAO, WAN-LI WANG, ZHUANG HAN, and ZI-XING ZHANG. "EFFECTS OF SINGLE CROUCH WALKING GAITS ON FATIGUE DAMAGES OF LOWER EXTREMITY MAIN MUSCLES." Journal of Mechanics in Medicine and Biology 19, no. 07 (November 2019): 1940046. http://dx.doi.org/10.1142/s0219519419400463.
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Single crouch walking gait (SCWG) is one of the main walking gaits when one of the legs is injured. However, the research on movement biomechanical characteristics (MBC) of lower extremity in SCWG has not been reported. So, the aim of this study is to analyze kinematics and main muscle fatigue damages of lower extremity in SCWG. Gaits data were collected with functional assessment biomechanics (FAB) system which applies the real-time wireless gait phase detection system, the movement function relations of joints of lower extremity were obtained by fitting the collected data in normal walking gait (NWG) and SCWG with Fourier series, the fitted movement functions were input to 3D human musculoskeletal model as driving functions for human movement to analyze the differences of MBC between SCWG and NWG. Finally, the muscle contractions were used to evaluate muscle fatigue damage. Compared with NWG, the result shows that the movement range of the joint angles of lower extremity are reduced in SCWG, the change law of hip internal/external rotation angle (IERA) has a significant difference, and the change laws of other joint angles are similarly between SCWG and NWG. The muscle contractions of Gluteus maximum (GMAX) 2, Gluteus meddle (GMED) 1, GMED2, Iliacus (ILI), Rectus femoris (RFEM), Soleus (SOL), Gastrocnemius (GAS) and Vastus lateralis (VLAT) are significantly larger in SCWG than in NWG (except GlutMed2 which is about 20–40% and VLAT which is about 63.8–76.1% of gait cycle), namely, these muscles easily cause muscle damages in SCWG. The contraction change of Adductor magnus (AMAG) is dispersed, so AMAG is prone to muscle fatigue in SCWG. The study results will fill in the gaps in the MBC of lower extremity in SCWG and provide data for Rehabilitation Medical Technology (RMT) and development of rehabilitation equipment of lower extremity.
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Choi, Byunghun, Changhoon Seo, Sanghoon Lee, and Byungun Kim. "Control of power-augmenting lower extremity exoskeleton while walking with heavy payload." International Journal of Advanced Robotic Systems 16, no. 1 (January 1, 2019): 172988141983053. http://dx.doi.org/10.1177/1729881419830535.
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This article presents a design and control framework for a prototype of lower extremity exoskeleton to enhance the human strength during locomotion. The hybrid control strategy is practically applied according to the two gait phases, that is, stance and swing. The weight shift method based on human’s weight shift information was proposed and implemented to acquire the detection of gait phase. In the stance phase, a stiff virtual wall method is applied to support the entire weight of the exoskeleton while carrying a heavy payload. Direct feedback and feed-forward torque control are used to reduce mechanical impedance in the swing phase. In experiments, to verify the performance of the proposed control strategy, a human subject wearing the prototype of power-augmenting lower extremity exoskeleton was able to walk with a 50-kg (110-lb) payload at a maximum speed of 1.67 m/s (6 km/h). Satisfactory results were obtained with regard to walking experiments with the heavy payload.
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Lee, Hoi Leong, Abu Bakar Shahriman, Siti Khadijah Za'aba, Khairunizam Wan, S. Ahmad Roohi, and Mohamad Razlan Zuradzman. "Upper Extremity Vein Graft Monitoring Device after Surgery Procedure: A Preliminary Study." Advanced Materials Research 925 (April 2014): 656–60. http://dx.doi.org/10.4028/www.scientific.net/amr.925.656.
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In most cases, surgical vein bypass or interposition vein grafting was used in both primary management of crush-avulsion amputations and on intervention for rehabilitating the patency of occluded arteries via microvascular surgery. However, surgical revascularization has significant shortcomings, principal among which is the high rate of accelerated thrombosis that develops in arterialised vein graft which renders the vein graft susceptible to acute occlusion and eventually give rise to graft failure. Evaluaion and detection of vein graft failure is essential as that will be the starting point for the clinician to make the diagnosis and safeguard patency of implanted vein graft which would otherwise fail. Unfortunately, most of the available diagnostic and monitoring tools available in the market are expensive, hence not all the hospital, private clinic and others medical centers that fully-equipped with these type of equipments. The objective of this study is to design and develop a low-cost and non-invasive vein graft monitoring prototype that able to provide high accuracy in predicting the vein graft patency and meanwhile providing the short-term monitoring on vein graft right after surgery procedure. Impedance plethysmography (IPG) was employed to measure pulsatile changes in longitudinal impedace to quantify arterial blood flow and pulsatile blood volume. Tetra-polar electrode measurement system was implemented by introduce a constant 1-mA AC current (I) at frequency of 100 kHz in the two outer electrodes. The voltage (V) is measured between the two inner electrodes, and the resulting impedance (Z) is calculated using Ohm’s Law. Arterial blood flow and pulsatile blood volume can then be estimated using impedance related volume conduction equation. By measuring the changes in electrical bioimpedance which can be used to derive important hemodynamic variables, it allows the postoperative graft surveillance and early detection atherosclerosis and thrombosis as well as estimate its severity that leads to the vein graft failure.
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Popov, Tatjana, Slobodan Gnjato, and Goran Trbić. "Changes in extreme temperature indices over the Peripannonian region of Bosnia and Herzegovina." Geografie 124, no. 1 (2019): 19–40. http://dx.doi.org/10.37040/geografie2019124010019.
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The paper analyzes changes in extreme temperature indices over the Peripannonian region of Bosnia and Herzegovina. Data on daily minimum and maximum temperatures during the period 1961–2016 from four meteorological stations were used for the calculation in the RClimDex (1.0) sopware trends in 16 indices recommended by the Expert team on climate change detection and indices. The estimated significant upward tendency in indices of warm extremes and downward in cold-related indices confirm that warming is present. The highest trend values were obtained for indices TXx, TNn, TN90p, TX90p, SU25, SU30 and WSDI. The results indicate significant distributional changes in the period 1987−2016 compared to the period 1961−1990. A significant positive (negative) correlation between the East-Atlantic pattern and indices of warm (cold) extremes was determined throughout the year. In winter and spring, significant links to the North Atlantic Oscillation and the Arctic Oscillation, respectively, were also found.
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Ntoumos, Athanasios, Panos Hadjinicolaou, George Zittis, and Jos Lelieveld. "Updated Assessment of Temperature Extremes over the Middle East–North Africa (MENA) Region from Observational and CMIP5 Data." Atmosphere 11, no. 8 (July 31, 2020): 813. http://dx.doi.org/10.3390/atmos11080813.
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The objective of this analysis is to provide an up-to-date observation-based assessment of the evolution of temperature extremes in the Middle East–North Africa (MENA) region and evaluate the performance of global climate model simulations of the past four decades. A list of indices of temperature extremes, based on absolute level, threshold, percentile and duration is used, as defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). We use daily near-surface air temperature (Tmax and Tmin) to derive the indices of extremes for the period 1980–2018 from: (i) re-analyses (ERA-Interim, MERRA-2) and gridded observational data (Berkeley Earth) and (ii) 18 CMIP5 model results combining historical (1950–2005) and scenario runs (2006–2018 under RCP 2.6, RCP 4.5 and RCP 8.5). The CMIP5 results show domain-wide strong, statistically significant warming, while the observation based ones are more spatially variable. The CMIP5 models capture the climatology of the hottest areas in the western parts of northern Africa and the Gulf region with the thewarmest day (TXx) > 46 °C and warmest night (TNx) > 33 °C. For these indices, the observed trends are about 0.3–0.4 °C/decade while they are 0.1–0.2 °C/decade stronger in the CMIP5 results. Overall, the modeled climate warming up to 2018, as reflected in the indices of temperature extremes is confirmed by re-analysis and observational data.
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Esayas, Befikadu, Belay Simane, Ermias Teferi, Victor Ongoma, and Nigussie Tefera. "Trends in Extreme Climate Events over Three Agroecological Zones of Southern Ethiopia." Advances in Meteorology 2018 (October 16, 2018): 1–17. http://dx.doi.org/10.1155/2018/7354157.
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The study aims to assess trends in extremes of surface temperature and precipitation through the application of the World Meteorological Organization’s (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI) on datasets representing three agroecological zones in Southern Ethiopia. The indices are applied to daily temperature and precipitation data. Nonparametric Sen’s slope estimator and Mann–Kendall’s trend tests are used to detect the magnitude and statistical significance of changes in extreme climate, respectively. All agroecological zones (AEZs) have experienced both positive and negative trends of change in temperature extremes. Over three decades, warmest days, warmest nights, and coldest nights have shown significantly increasing trends except in the midland AEZ where warmest days decreased by 0.017°C/year (p<0.05). Temperature extreme’s magnitude of change is higher in the highland AEZ and lower in the midland AEZ. The trend in the daily temperature range shows statistically significant decrease across AEZs (p<0.05). A decreasing trend in the cold spell duration indicator was observed in all AEZs, and the magnitude of change is 0.667 days/year in lowland (p<0.001), 2.259 days/year in midland, and 1 day/year in highland (p<0.05). On the contrary, the number of very wet days revealed a positive trend both in the midland and highland AEZs (p<0.05). Overall, it is observed that warm extremes are increasing while cold extremes are decreasing, suggesting considerable changes in the AEZs.
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Hansen, Steven M., Luke E. Schepers, Ruchira Pratihar, Jackson Tibbett, Gilberto Vallejo, Graham Grubbs, Thomas Fisher, Paul E. Hansen, and Craig J. Goergen. "Hemodynamic Assay of Hind Limb in Multiple Animal Models." Military Medicine 186, Supplement_1 (January 1, 2021): 351–57. http://dx.doi.org/10.1093/milmed/usaa446.
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ABSTRACT Introduction Measuring hemodynamic characteristics of injured limbs is paramount to early identification of potentially damaging ischemic conditions, but can often prove difficult attributable to a multitude of factors. Here, we present an in vivo optical imaging technique to characterize pulsatile blood flow quality through the distal extremity in multiple animal models that replicate the signs of distal extremity ischemia. The purpose of this study is to examine the feasibility of the optical imaging technique and relevance to hemodynamic complications such as acute compartment syndrome (ACS) and nonobvious hemorrhage. Materials and Methods In one pig and six mice, three different methods were used to create ischemic conditions in the lower extremity, producing symptoms similar to what is observed in ACS. In each condition, perfusion to the distal extremity was measured with the hemodynamic detection device (HDD; Odin Technologies), an optical assessment tool for perfusion and blood flow quality. Results We observed a profound decrease in extremity perfusion immediately after onset of ischemia in all three models. In the porcine model, the HDD’s measurements demonstrated similar characteristic flow between the various measurement locations. After the tourniquet was applied, the HDD revealed a 95% decrease in normalized perfusion value (npv) while the intracompartmental pressure rose from 5 to 52 mmHg (a 47mmHg increase). After the tourniquet was removed during reperfusion, the normalized blood flow returned to baseline and the intracompartmental pressure dropped from 20 to 6 mmHg in less than 5 minutes. For each mouse, the HDD test leg demonstrated a measurement of 0.97 npv before femoral ligation and 0.05 npv after femoral ligation, an 89% decrease (P < .01) in flow. Pulsed-wave Doppler ultrasound (PWDU) measurements on the test leg had pre-ligation measurement of 0.84 npv and a post-ligation measurement of 0.001 npv, a 99% decrease. These PWDU measurements revealed almost complete stoppage of blood flow during ischemia, followed by a substantial increase after the femoral artery ligation was removed. Conclusions Here, we show that a novel, optics-based sensing system can be used to diagnose and assess ACS in animal models. This technology is comparable to other standards used to monitor ACS and nonobvious hemorrhage and may also be a plausible alternative to prolonged invasive monitoring of patients with sustained extremity trauma.
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Durre, Imke, Matthew J. Menne, Byron E. Gleason, Tamara G. Houston, and Russell S. Vose. "Comprehensive Automated Quality Assurance of Daily Surface Observations." Journal of Applied Meteorology and Climatology 49, no. 8 (August 1, 2010): 1615–33. http://dx.doi.org/10.1175/2010jamc2375.1.
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Abstract This paper describes a comprehensive set of fully automated quality assurance (QA) procedures for observations of daily surface temperature, precipitation, snowfall, and snow depth. The QA procedures are being applied operationally to the Global Historical Climatology Network (GHCN)-Daily dataset. Since these data are used for analyzing and monitoring variations in extremes, the QA system is designed to detect as many errors as possible while maintaining a low probability of falsely identifying true meteorological events as erroneous. The system consists of 19 carefully evaluated tests that detect duplicate data, climatological outliers, and various inconsistencies (internal, temporal, and spatial). Manual review of random samples of the values flagged as errors is used to set the threshold for each procedure such that its false-positive rate, or fraction of valid values identified as errors, is minimized. In addition, the tests are arranged in a deliberate sequence in which the performance of the later checks is enhanced by the error detection capabilities of the earlier tests. Based on an assessment of each individual check and a final evaluation for each element, the system identifies 3.6 million (0.24%) of the more than 1.5 billion maximum/minimum temperature, precipitation, snowfall, and snow depth values in GHCN-Daily as errors, has a false-positive rate of 1%−2%, and is effective at detecting both the grossest errors as well as more subtle inconsistencies among elements.
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Worrell, Teddy W., Laurie D. Booher, and Karla M. Hench. "Closed Kinetic Chain Assessment Following Inversion Ankle Sprain." Journal of Sport Rehabilitation 3, no. 3 (August 1994): 197–203. http://dx.doi.org/10.1123/jsr.3.3.197.
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The purpose of this study was to compare the injured versus noninjured lower extremity on three single-leg hop tests following inversion ankle sprain. Twenty-two subjects with a history of unilateral inversion ankle sprain participated in this study. Subjects performed the three single-leg hop tests (hop for distance, hop for time, and agility hop). An independentttest was used to compare extremities. No significant differences existed on any hop test for the 22 subjects. In 8 of the 22 subjects who reported pain with activities of daily living and/or sports activities, an independentttest revealed no significant difference on hop test performance between extremities. We conclude that these three single-leg hop tests lack sensitivity (validity) in detecting lower extremity performance deficits as reported by the subjects following inversion ankle sprain.
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Ņesteroviča, Darja, Ainārs Stepens, and Normunds Vaivads. "Peak Plantar Pressure as a Risk Factor for Lower Extremity Overuse Injury Among Infantry Soldiers." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 75, no. 1 (February 1, 2021): 52–57. http://dx.doi.org/10.2478/prolas-2021-0009.
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Abstract The majority of reported injuries among military populations are injuries due to cumulative repetitive microtrauma — overuse injuries. Plantar pressure measurement is a simple tool to analyse lower limb biomechanics through the assessment of forces applied to the foot. This study aimed to determine the relation between peak plantar pressure and lower extremity overuse. Sixty-six active-duty infantry male soldiers, with mean age 29.7 years (range 22–40 years), and mean service time 5.2 years (range 1–15 years) participated. The highest peak plantar pressure (PPP) at the forefoot occurred at the hallux (cases: 50.82 n/cm2, SD = 38.84; control: 34.39 n/cm2, SD= 28.03) and 3rd metatarsal head (cases: 54.40 n/cm2, SD = 33.83; control: 49.16 n/cm2, SD=28.87). The study demonstrated elevated PPP among cases. Statistically significant results were found at the hallux (χ2(1) = 6.8; p = 0.01), medial heel (χ2(1) = 5.18; p = 0.02) and lateral heel (χ2(1) = 12.12; p < 0.01) regions. The results show that plantar pressure assessment could be used as a useful screening tool for early lower extremity overuse injury detection.
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Santos, Karen A. Delos, Shawn C. Stafford, James L. Szalma, Tal Oron-Gilad, and P. A. Hancock. "Evaluation of Threat by Police Officers: Initial Findings." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 49, no. 9 (September 2005): 846–49. http://dx.doi.org/10.1177/154193120504900901.
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Police officers' threat perception of static images was examined using images reflecting the range of five threat categories on which police officers are trained. Thirteen experienced officers from a police departments in the southeastern United States participated in this study. Officers rated their perceived threat level for 110 images that were presented to them on a laptop computer. Each of these images was rated twice by each officer. Officers used all five categories to rate the stimuli, and their responses to the extremes (images rated as 1 or 5) were faster than responses to more ambiguous stimuli in the other categories. These results were generally consistent with predictions based on Fuzzy Signal Detection Theory. Further studies will evaluate performance with these images in the context of a signal detection task. Once fully developed, this tool could be used to evaluate new recruits' decision-making process before given the green light to carry a badge. These assessments could also be used as a modified training tool for experienced officers if the stimuli were to be placed in a semiimmersive environment.
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Shrestha, Ila. "Spatially Distribution of Quercus semecarifolia in Rasuwa District Using GIS and RS." International Journal of Applied Sciences and Biotechnology 3, no. 4 (December 30, 2015): 747–49. http://dx.doi.org/10.3126/ijasbt.v3i4.13980.
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The paper is based on the case study of Rasuwa district, is a land of geographical extremes, ranging from 600 m Betrabati river to 7234 m Langtang Lirung, the highest point in the northwest. The study was carried out on the detection of Quercus semecarifolia J.E.Smith using Remote-Sensing and Geographic Information System technique. SPOT Image and ERDAS Software have used for the image processing. The program has detected the different types of ecological parameters in tropical to alpine zone and specified the plant species in the study after ground truthing.Int J Appl Sci Biotechnol, Vol 3(4): 747-749
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Boiarov, Viktor, Mikhail Larkin, Oleh Kyrychenko, Sergey Penkov, and Oleh Kruhlov. "Features of the investigation of hooliganism committed by football fans." Cuestiones Políticas 39, no. 69 (July 17, 2021): 513–29. http://dx.doi.org/10.46398/cuestpol.3969.32.
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The article is devoted to the analysis of some features of the investigation of football hooliganism. The current state and trends of football hooliganism are considered (including during the COVID-19 pandemic). The main problems faced by the investigation authorities during the detection and investigation of football hooliganism have been identified. In the process of working on the article, the scientific literature on informal youth groups, the fight against extremism, the investigation of group crimes of football fans was analyzed. The purpose of the study is to identify and study the features of the investigation of hooliganism committed by football fans. The object of research is the peculiarities of the investigation of hooliganism committed by football fans. During the writing of the article, the following methods were used: observation, analysis, synthesis, comparison, generalization, extrapolation, modeling, and information approach. As a result of the conducted research, the modern tendencies of football hooliganism are defined. Emphasis is placed on the peculiarities of the transformation of football fans. The principal problems of detection and investigation of football hooliganism are outlined, recommendations for prevention and counteraction to crimes committed by football fans are developed.
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Lewis, E. Neil, and Ira W. Levin. "Real-Time, Mid-Infrared Spectroscopic Imaging Microscopy Using Indium Antimonide Focal-Plane Array Detection." Applied Spectroscopy 49, no. 5 (May 1995): 672–78. http://dx.doi.org/10.1366/0003702953964066.
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A different approach toward mid-infrared spectroscopic imaging microscopy is introduced in which instrumentation is designed about an InSb multichannel, focal-plane array detector and a variable-bandpass dielectric filter. The system may be configured for either macroscopic or microscopic applications, and high-fidelity, chemically specific images may be acquired in real time. With the dielectric filter used in this assembly, continuous tuning is provided for the infrared 4000–2320 cm−1 spectral region with spectral resolutions of approximately 35–18 cm−1 at the extremes of this wavelength interval. The functioning of the imaging microscope is demonstrated with samples including polystyrene microspheres, preparations of lipids and an amino acid embedded in KBr disks, and a tissue sample derived from a coronal slice of a monkey cerebellum.
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Jokiniitty, Elina, Lauri Hokkinen, Pekka Kumpulainen, Yrjö Leskinen, Terho Lehtimäki, Niku Oksala, and Antti Roine. "Urine headspace analysis with field asymmetric ion mobility spectrometry for detection of chronic kidney disease." Biomarkers in Medicine 14, no. 8 (June 2020): 629–38. http://dx.doi.org/10.2217/bmm-2020-0085.
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Electronic noses (eNoses) are an emerging class of experimental diagnostic tools. They are based on the detection of volatile organic compounds. Urine is used as sample medium in several publications but neither the effect of chronic kidney disease (CKD) on the analysis nor the potential to detect CKD has been explored. Materials & methods: We utilized an eNose based on field asymmetric ion mobility spectrometry (FAIMS) technology to classify urine samples from CKD patients and controls. Results: We were able to differentiate extremes of kidney function with an accuracy of 81.4%. Conclusion: In this preliminary study, applying eNose technology we were able to distinguish the patients with impaired kidney function from those with normal kidney function.
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Mitková, Veronika Bačová, and Dana Halmová. "Statistical Analysis and Trend Detection of the Hydrological Extremes in the Váh River at Liptovský Mikuláš." Acta Horticulturae et Regiotecturae 24, s1 (May 1, 2021): 80–89. http://dx.doi.org/10.2478/ahr-2021-0013.
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Abstract Natural climate fluctuation, as well as expected climate change, brings additional water regimes in the flow of a number of serious issues and uncertainties. The upper parts of the river basins are suitable for studying the effect of potential climate change or increased air temperature on drainage conditions in the basin. The Váh River is the biggest left-side Danube River tributary and the second biggest river in Slovakia. Gauging station Váh – Liptovský Mikuláš is the final profile above the water reservoir Liptovská Mara, one of the largest reservoirs in Slovakia. The contribution deals with the trend analysis of the extreme flows regime and the waves volume belongs to the annual maximum flow at gauging station Váh – Liptovský Mikuláš in a selected time period (1931–2015). Consequently, the trend analyses of precipitation depth and air temperature have been made at three selected meteorological stations located in the upper part of the Váh River basin. We have used the Mann-Kendall nonparametric test, which is one of the most widely used nonparametric tests to detect significant trends in a time series.
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Lin, Shayne, Jotvarinder Mann, Avril Mansfield, Rosalie H. Wang, Jocelyn E. Harris, and Babak Taati. "Investigating the feasibility and acceptability of real-time visual feedback in reducing compensatory motions during self-administered stroke rehabilitation exercises: A pilot study with chronic stroke survivors." Journal of Rehabilitation and Assistive Technologies Engineering 6 (January 2019): 205566831983163. http://dx.doi.org/10.1177/2055668319831631.
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Introduction Homework-based rehabilitation programs can help stroke survivors restore upper extremity function. However, compensatory motions can develop without therapist supervision, leading to sub-optimal recovery. We developed a visual feedback system using a live video feed or an avatar reflecting users' movements so users are aware of compensations. This pilot study aimed to evaluate validity (how well the avatar characterizes different types of compensations) and acceptability of the system. Methods Ten participants with chronic stroke performed upper-extremity exercises under three feedback conditions: none, video, and avatar. Validity was evaluated by comparing agreement on compensations annotated using video and avatar images. A usability survey was administered to participants after the experiment to obtain information on acceptability. Results There was substantial agreement between video and avatar images for shoulder elevation and hip extension (Cohen's κ: 0.6–0.8) and almost perfect agreement for trunk rotation and flexion (κ: 0.80–1). Acceptability was low due to lack of corrective prompts and occasional noise with the avatar display. Most participants suggested that an automatic compensation detection feature with visual and auditory cuing would improve the system. Conclusion The avatar characterized four types of compensations well. Future work will involve increasing sensitivity for shoulder elevation and implementing a method to detect compensations.
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Dzienis, Paweł, Romuald Mosdorf, Daniel Tomaszuk, and Tomasz Wyszkowski. "A hydrodynamic criterion of alternative bubble departures." Thermal Science, no. 00 (2019): 417. http://dx.doi.org/10.2298/tsci190510417d.
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The bubble departures from two neighbouring brass nozzles (with inner diameter of 1.1 mm) in three liquids: distilled water, mineral and synthetic engine oils were investigated. The numerical simulations were used for reconstruction of liquid flow around the departing bubbles. Bubble movements in liquid have been recorded using a high speed camera. The 2D bubble paths have been reconstructed using: Laplacian of Gaussian filters, algorithm of detection of local extremes of image brightness and Kalman filter. It was shown that during alternative bubble departures bubble paths become repeatable. The dimensionless number (similar to Strouhal number) was proposed to describe oscillating liquid flow generated by departing bubbles over the nozzle outlet. Such number was used for defining the hydrodynamic criterion of alternative bubble departures.
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Klutse, Nana Ama Browne, Kwesi Akumenyi Quagraine, Francis Nkrumah, Kwesi Twentwewa Quagraine, Rebecca Berkoh-Oforiwaa, Joshua Fafanyo Dzrobi, and Mouhamadou Bamba Sylla. "The Climatic Analysis of Summer Monsoon Extreme Precipitation Events over West Africa in CMIP6 Simulations." Earth Systems and Environment 5, no. 1 (January 2021): 25–41. http://dx.doi.org/10.1007/s41748-021-00203-y.
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AbstractWe evaluate the capability of 21 models from the new state-of-the-art Coupled Model Intercomparison Project, Phase 6 (CMIP6) in the representation of present-day precipitation characteristics and extremes along with their statistics in simulating daily precipitation during the West African Monsoon (WAM) period (June–September). The study uses a set of standard extreme precipitation indices as defined by the Expert Team on Climate Change Detection and Indices constructed using CMIP6 models and observational datasets for comparison. Three observations; Global Precipitation Climatology Project (GPCP), Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), and Tropical Applications of Meteorology using SATellite and ground-based observation (TAMSAT) datasets are used for the validation of the model simulations. The results show that observed datasets present nearly the same spatial pattern but discrepancies in the magnitude of rainfall characteristics. The models show substantial discrepancies in comparison with the observations and among themselves. A number of the models depict the pattern of rainfall intensity as observed but some models overestimate the pattern over the coastal parts (FGOALS-f3-L and GFDL-ESM4) and western part (FGOALS-f3-L) of West Africa. All model simulations explicitly show the pattern of wet days but with large discrepancies in their frequencies. On extreme rainfall, half of the models express more intense extremes in the 95th percentiles while the other half simulate less intense extremes. All the models overestimate the mean maximum wet spell length except FGOALS-f3-L. The spatial patterns of the mean maximum dry spell length show a good general agreement across the different models, and the observations except for four models that show an overestimation in the Sahara subregion. INM-CM4-8 and INM-CM5-0 display smaller discrepancies from their long-term average rainfall characteristics, in terms of extreme rainfall estimates than the other CMIP6 datasets. For the frequency of heavy rainfall, TaiESM1 and IPSL-CMGA-LR perform better when compared with observational datasets. MIROC6 and GFDL-ESM4 displayed the largest error in representing the frequency of heavy rainfall and 95th percentile extremes, and therefore, cannot be reliable. The study has assessed how rainfall extremes are captured in both observation and the models. Though there are some discrepancies, it gives room for improvement of the models in the next version of CMIP.
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Purger, David, Abdullah H. Feroze, Omar Choudhri, Leslie Lee, Jaime Lopez, and Robert L. Dodd. "Detection of acute femoral artery ischemia during neuroembolization by somatosensory and motor evoked potential monitoring." Interventional Neuroradiology 21, no. 3 (May 26, 2015): 397–400. http://dx.doi.org/10.1177/1591019915583219.
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Neuromonitoring can be used to map out particular neuroanatomical tracts, define physiologic deficits secondary to specific pathology or intervention, or predict postoperative outcome and proves essential in the detection of central and peripheral ischemic events during neurosurgical intervention. Herein, we describe an instance of elective balloon-assisted coiling of a recurrent basilar tip aneurysm in a 61-year-old woman, where intraoperative somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (TcMEPs) were lost in the right lower extremity intraoperatively. We aim to highlight that targeted use of monitoring proves advantageous in both the open surgical and endovascular setting, even in the avoidance of potential iatrogenic peripheral nerve damage and limb ischemia as documented herein. Consideration of the increased risk for peripheral ischemia in the neurointerventional setting is especially imperative in particular populations where blood vessels might be of diminished size, such as in infants, young children, and severely deconditioned adults.
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Geary, Michael, Raymond Glenn Gaston, and Bryan Loeffler. "Surgical and technological advances in the management of upper limb amputees." Bone & Joint Journal 103-B, no. 3 (March 1, 2021): 430–39. http://dx.doi.org/10.1302/0301-620x.103b3.bjj-2020-1184.r1.
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Upper limb amputations, ranging from transhumeral to partial hand, can be devastating for patients, their families, and society. Modern paradigm shifts have focused on reconstructive options after upper extremity limb loss, rather than considering the amputation an ablative procedure. Surgical advancements such as targeted muscle reinnervation and regenerative peripheral nerve interface, in combination with technological development of modern prosthetics, have expanded options for patients after amputation. In the near future, advances such as osseointegration, implantable myoelectric sensors, and implantable nerve cuffs may become more widely used and may expand the options for prosthetic integration, myoelectric signal detection, and restoration of sensation. This review summarizes the current advancements in surgical techniques and prosthetics for upper limb amputees. Cite this article: Bone Joint J 2021;103-B(3):430–439.
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Kang, Congxuan, Zujiang Luo, Wen Zong, and Jian Hua. "Impacts of Urbanization on Variations of Extreme Precipitation over the Yangtze River Delta." Water 13, no. 2 (January 10, 2021): 150. http://dx.doi.org/10.3390/w13020150.
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The urbanization process is the hallmark of the population’s economic activities and land-use types, including population-, economic-, and landscape-urbanization. The question of how to classify the stations into urbanized and suburbanized stations is important for detecting the contribution rates of urbanization to precipitation extremes. This study used the fuzzy c-means clustering method to classify different urbanized level stations by population, economy, and impervious surface in the Suzhou-Wuxi-Changzhou urban agglomeration. Based on the change trends of six extreme precipitation indices, the contribution rates of urbanization to the precipitation extremes were estimated. The results show that the increasing indices were the intensity indices, while the decreasing indices were the duration indices during 1980–2015. Moreover, high urbanization tended to have a higher contribution to the most extreme precipitation indices, especially the intensity indices, than urbanization in the medium-size cities, indicating the urbanization leads to the phenomenon of extreme precipitation enhancement. The results of the three kinds of classification methods were different, especially the classification by the impervious area. This paper investigated the spatiotemporal changes in precipitation extremes and the contribution of urbanization to extreme precipitation, which will provide support for the development of urban agglomeration in the future.
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Kang, Congxuan, Zujiang Luo, Wen Zong, and Jian Hua. "Impacts of Urbanization on Variations of Extreme Precipitation over the Yangtze River Delta." Water 13, no. 2 (January 10, 2021): 150. http://dx.doi.org/10.3390/w13020150.
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The urbanization process is the hallmark of the population’s economic activities and land-use types, including population-, economic-, and landscape-urbanization. The question of how to classify the stations into urbanized and suburbanized stations is important for detecting the contribution rates of urbanization to precipitation extremes. This study used the fuzzy c-means clustering method to classify different urbanized level stations by population, economy, and impervious surface in the Suzhou-Wuxi-Changzhou urban agglomeration. Based on the change trends of six extreme precipitation indices, the contribution rates of urbanization to the precipitation extremes were estimated. The results show that the increasing indices were the intensity indices, while the decreasing indices were the duration indices during 1980–2015. Moreover, high urbanization tended to have a higher contribution to the most extreme precipitation indices, especially the intensity indices, than urbanization in the medium-size cities, indicating the urbanization leads to the phenomenon of extreme precipitation enhancement. The results of the three kinds of classification methods were different, especially the classification by the impervious area. This paper investigated the spatiotemporal changes in precipitation extremes and the contribution of urbanization to extreme precipitation, which will provide support for the development of urban agglomeration in the future.
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Li, Junxun, Fan Zhang, Chujia Liang, Zhuangjian Ye, Shaoqian Chen, and Jing Cheng. "The Diagnostic Efficacy of Age-Adjusted D-Dimer Cutoff Value and Pretest Probability Scores for Deep Venous Thrombosis." Clinical and Applied Thrombosis/Hemostasis 25 (January 1, 2019): 107602961982631. http://dx.doi.org/10.1177/1076029619826317.
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This study seeks to evaluate the diagnostic value of D-Dimer Plus and Innovance D-Dimer as well as the age-adjusted cutoff value for D-dimer detection in combination with 4 pretest probability (PTP) scores for deep venous thrombosis (DVT). A total of 688 patients referred for lower extremity vascular compression venous ultrasonography for suspected DVT from January 2016 to May 2018 in the First Affiliated Hospital of Sun Yat-sen University underwent D-dimer tests combining with 4 PTP scores. The diagnostic efficacy of the Wells score was the highest of the 4 PTP scores. The diagnostic efficacy of Innovance D-Dimer for DVT was greater than that of D-Dimer Plus, with better sensitivity and negative predictive value, which were both greater than 98%. If the cutoff values were adjusted by age, the Innovation D-Dimer could further improve both the specificity and the positive predictive value, providing better diagnostic performance. When the 2 D-dimer detections were used in combination with 4 PTP scores for DVT diagnosis, separately, both the positive predictive value and the negative predictive value significantly improved for D-Dimer Plus, and the positive predictive values significantly improved for Innovance D-Dimer. However, the sensitivity, specificity, and negative predictive values did not obviously change. For our patients, Wells score had the best diagnostic efficacy for our patients with suspected DVT among the 4 PTP scores. Innovance D-Dimer in combination with age-adjusted cutoff values exhibited increased sensitivity and negative predictive value for DVT diagnosis and was equivalent to the diagnostic efficacy of the Innovance D-Dimer in combination with PTP scores.
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Elhamamy, Nareman. "Evaluation of Fetal Mid-Thigh Soft Tissue Thickness and Femur Length for Estimation of Fetal Birth Weight." Women Health Care and Issues 3, no. 2 (June 26, 2020): 01–10. http://dx.doi.org/10.31579/2642-9756/023.
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Accurate calculation of fetal weight relies on two equally important factors: the use of a formula with strong intrinsic properties, and the use of sonographic biometric parameters that are not susceptible to errors in measurement. From a statistical perspective, the inclusion of multiple variables in a model improves multicollinearity chances and decreases each measurement's internal error. Precisely predicting estimated fetal weight during childbirth may have a significant impact on successful obstetric management, especially in the case of suspected macrosomia or low birth weight. Macrosomic fetuses can cause maternal and neonatal complications during childbirth, and low-born fetuses are at increased risk for perinatal morbidity and mortality. The main aim of the study was to assess the accuracy of measurement of mid-thigh soft tissue thickness and femur length, in estimation of expected fetal birth weight The study was conducted during the period January 2017 to August 2019, at Tanta University hospitals, Obstetrics & Gynecology department. 65 pregnant ladies at term (between 37-40weeks) were included in the study. Results: Mean difference between fetal weight by Hadlock formulae and actual fetal weight is -10.88g; percent difference is (0.32%). The difference statistically insignificant p>0.05. Mean difference between fetal weight by Scioscia’s formulae and Actual fetal weight is 2.83; the percent difference is (0.08%). The difference statistically insignificant p>0.05. Good agreement between Hadlock formulae and Actual Fetal Weight Kappa value (0.73).Also shows moderate agreement between Scioscia’s formulae and Actual Fetal Weight Kappa value (0.52). area under curve Hadlock formulae (0.79), Scioscia’s formulae (0.78) for detecting fetal weight ≥3500gm among pregnant women at 39-40 weeks of gestation. Conclusion: The mid-thigh soft tissue thickness and femur length can be used in estimation of expected fetal birth weight like as other sonographic parameters. The validity of Scioscia's formulae is not better than Hadlock formulae in detection of fetal weight less than 3500 gm. The validity of both formulae Scioscia's and Hadlock in detection of fetal weight more than 3500 gm. Reduced and cannot be dependable in extremes of weight.
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Maza, Kangdim Dingji, Umut Koldas, and Sait Aksit. "Challenges of Countering Terrorist Recruitment in the Lake Chad Region: The Case of Boko Haram." Religions 11, no. 2 (February 20, 2020): 96. http://dx.doi.org/10.3390/rel11020096.
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This article attempts to shed light on the challenges confronting relevant actors (state and non-state) in countering the threat of terrorism recruitment by focusing on the Boko Haram terrorist organization, whose presence and activities threaten the security of the Lake Chad region. The article uses a qualitative research technique combining key informant interviews with stakeholders familiar with the conflict, academic and non-academic documents, reports, and policy briefs. The findings of the article suggest that despite the various initiatives by stakeholders aimed at containing the strategies of recruitment, the group continues to expand its base by launching coordinated attacks that further destabilize the region. These challenges stem from a lack of a clear-cut counterterrorism strategy, a dearth in technological and mutual trust between actors and locals in the management and utilization of intelligence, and the inability of state institutions to ‘coerce and convince’ citizens in terms of its capacity to counter the danger of terrorism recruitment and expansion. The article, amongst other things, recommends a community policing model similar to the ‘Nyumba-Kumi security initiative’ adopted by most countries in East Africa for the effective assessment and detection of threat forces; the state and its agencies should show the capacity to coerce and convince in dealing with the (ideological, religious, social, and economic) conditions, drivers, and factors promoting the spread of terrorism as well as other forms of violent extremism in the society; furthermore, there is a need for stakeholders to adopt a comprehensive and holistic counterterrorism/violent extremism strategy to reflect present-day security challenges as well as to guarantee sustainable peace.
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Wang, Wenkang, Liancun Zhang, Kangjian Cai, Zhiheng Wang, Bainan Zhang, and Qiang Huang. "Design and Experimental Evaluation of Wearable Lower Extremity Exoskeleton with Gait Self-adaptivity." Robotica 37, no. 12 (May 21, 2019): 2035–55. http://dx.doi.org/10.1017/s0263574719000663.
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SummaryIn this paper, we present a passive lower extremity exoskeleton with a simple structure and a light weight. The exoskeleton does not require any external energy source and can achieve energy transfer only by human body’s own gravity. The exoskeleton is self-adaptive to human gait to achieve basic matching therewith. During walking, pulling forces are generated through Bowden cables by pressing plantar power output devices by feet, and the forces are transmitted to the exoskeleton through a crank-slider mechanism to enable the exoskeleton to provide torques for the ankle and knee joints as required by the human body during the stance phase and the swing phase. Our self-developed gait detection system is used to perform experiments on kinematics, dynamics and metabolic cost during walking of the human body wearing the exoskeleton in different states. The experimental results show that the exoskeleton has the greatest influence on motion of the ankle joint and has the least influence on hip joint. With the increase in elastic coefficient of the spring, the torques generated at the joints by the exoskeleton increase. When walking with wearing k3EF exoskeleton at a speed of 0.5 m/s, it can save the most metabolic cost, reaching 13.63%.
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Costa, Rafaela Lisboa, Heliofábio Barros Gomes, Fabrício Daniel Dos Santos Silva, Rodrigo Lins Da Rocha Júnior, Giuliene Carla Dos Santos Silva, and William Max De Oliveira Romão. "Tendências em índices extremos de precipitação em Cabaceiras (PB) para períodos distintos." Revista Brasileira de Geografia Física 13, no. 1 (April 6, 2020): 271. http://dx.doi.org/10.26848/rbgf.v13.1.p271-285.
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Este trabalho teve como objetivo aplicar e estudar 11 índices de extremos de precipitação formulados pelo ETCCDI (Expert Team on Climate Change Detection and Indices, www.clivar.org/organization/etccdi), para a cidade de Cabaceiras-PB, utilizando dados diários de precipitação contínuos de 90 anos. Os índices foram calculados para o comprimento total da série, 1928 a 2017, assim como para três segmentos de 30 anos (1928-1957, 1958-1987 e 1988-2017). Os resultados evidenciaram que para muitos índices, tendências opostas e estatisticamente significativas podem ser observadas a depender do subperíodo estudado, assim como haver diferença entre estas tendências e as obtidas ao analisar-se o período total dos dados. Exemplos disso aconteceram para os índices R1mm, R10mm, R20mm, CWD e PRCPTOT. Trends in extreme precipitation indexes in Cabaceiras (PB) for different periods A B S T R A C TThis work aimed to apply and analyze 11 precipitation extremes indexes formulated by ETCCDI (Expert Team on Climate Change Detection and Indices, www.clivar.org/organization/etccdi), for the city of Cabaceiras, located in the Borborema mesoregion and microregion of Paraíba Oriental Cariri. A municipality in the semiarid region, it has the title of municipality where it rains less in Brazil, with an annual average of just over 300mm. Daily 90-year continuous precipitation data were used for the extreme indices, with the time series analyzed for four distinct periods, the total length of the series, 1928 to 2017, as well as three 30-year segments (1928-1957, 1958- 1987 and 1988-2017). The results showed that for many indices, opposite and significant trends can be observed depending on the sub period studied, as well as differences between these trends and those obtained by analyzing the total data period. The R1, R10 and R20mm indices show significant negative trends in the 1928-1957 sub period, but positive in the following two sub periods, reflecting a significant positive trend in the total period from 1928 to 2017. Other interesting examples are CDD indices for consecutive dry days, and PRCPTOT, for total annual rainfall with rainfall greater than 1mm. The CDD showed significant positive trend only in the 1928-1957 sub period, but non-significant negative trends in the subsequent sub periods, reflecting non-significant negative trends in the total length of the series. The PRCPTOT index shows behavior opposite to the CDD index, with a significant negative trend in the 1928-1957 sub period, positive in 1958-1987 and negative again in 1988-2017, but for the total length of the series the trend is positive and significant. These results show that the analysis of extreme trends is noticeably sensitive to the sample of the analyzed period, and may not reflect the reality of the time series the longer the total length of the time series, and need to be used with caution.Keywords: climate variability, dry and wet periods, semiarid.