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1
Shin, Kyuhee, Joon Jin Song, Wonbae Bang, and GyuWon Lee. "Quantitative Precipitation Estimates Using Machine Learning Approaches with Operational Dual-Polarization Radar Data." Remote Sensing 13, no. 4 (February 14, 2021): 694. http://dx.doi.org/10.3390/rs13040694.
Повний текст джерелаАнотація:
Traditional radar-based rainfall estimation is typically done by known functional relationships between the rainfall intensity (R) and radar measurables, such as R–Zh, R–(Zh, ZDR), etc. One of the biggest advantages of machine learning algorithms is the applicability to a non-linear relationship between a dependent variable and independent variables without any predefined relationships. We explored the potential use of two supervised machine learning methods (regression tree and random forest) in rainfall estimation using dual-polarization radar variables. The regression tree does not require normalization and scaling of data; however, this method is quite unstable since each split depends on the parent split. Since the random forest is an ensemble method of regression trees, it has less variability in prediction compared with regression trees, but consumes more computer resources. We considered several different configurations for machine learning algorithms with different sets of dependent and independent variables. The random forest model was appropriately tuned. In the test of variable importance, the specific differential phase (differential reflectivity) was the most important variable to predict the rainfall rate (residual that is the difference between the true rainfall rate and the one estimated from the R–Z relationship). The models were evaluated by 10-fold cross-validation. The best model was the random forest model using a residual with the non-classified training set. The results indicated that the machine learning algorithms outperformed the traditional R–Z relationship. Then, we applied the best machine learning model to an S-band dual-polarization radar (Mt. Myeonbong) and validated the result with ground rain gauges. The results of the application to radar data showed that the estimates of the residuals had spatial variability. The stratiform and weak rain areas had positive residuals while convective areas had negative residuals, indicating that the spatial error structure driven by the R–Z relationship was well captured by the model. The rainfall rates of all pixels over the study area were adjusted with the estimated residuals. The rainfall rates adjusted by residual showed excellent agreement with the rain gauge, especially at high rainfall rates.
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Ortolani, Matteo, Cristy Leonor Azanza Ricardo, and Paolo Scardi. "Analysis of Residual Stress-Texture Relationships in Thin Films." Advanced Materials Research 89-91 (January 2010): 425–30. http://dx.doi.org/10.4028/www.scientific.net/amr.89-91.425.
Повний текст джерелаАнотація:
A new software was developed for the X-ray stress analysis of textured materials, especially useful in the case of thin films and coating. Literature data for a sputtered Cu thin film were used as a test case. Good agreement with the published results was found considering a grain interaction mechanism based on the combination of four models (Ruess/Voigt/Vook-Witt/inverse Vook-Witt). A similar value for the in-plane residual stress was obtained by the Eshelby-Kröner model, by optimizing the grain aspect-ratio. Main features and numerical/graphic output are briefly discussed.
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Sharma, M. L. "Attenuation relationship for estimation of peak ground horizontal acceleration using data from strong-motion arrays in India." Bulletin of the Seismological Society of America 88, no. 4 (August 1, 1998): 1063–69. http://dx.doi.org/10.1785/bssa0880041063.
Повний текст джерелаАнотація:
Abstract An attenuation relationship for peak horizontal ground accelerations for Himalayan region in India has been developed. The data base consists of 66 peak ground horizontal accelerations from five earthquakes recorded by strong-motion arrays in India. The present analysis uses a two-step stratified regression model. The attenuation relationship proposed is log ( A ) = − 1.072 + 0.3903 M − 1.21 log ( X + e 0.5873 M ) , where A is the peak ground acceleration (g), M is the magnitude, and X is the hypocentral distance from the source. The residual sum of squares is 0.14. Comparison with other such attenuation relationships have been made. The proposed relationship giving lesser values at shorter distances compared to other relationships needs further investigation with a larger data set. The attenuation relationship needs upgradation when more data become available in future.
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Arciszewski, Tim J., and David R. Roberts. "Analyzing Relationships of Conductivity and Alkalinity Using Historical Datasets from Streams in Northern Alberta, Canada." Water 14, no. 16 (August 14, 2022): 2503. http://dx.doi.org/10.3390/w14162503.
Повний текст джерелаАнотація:
Many measurements, tools, and approaches are used to identify and track the influence of human activities on the physicochemical status of streams. Commonly, chemical concentrations are utilized, but in some areas, such as downstream of coal mines, capacity indices such as specific conductivity have also been used to estimate exposure and risk. However, straightforward tools such as conductivity may not identify human influences in areas with saline groundwater inputs, diffuse exposure pathways, and few discharges of industrial wastewater. Researchers have further suggested in conductivity relative to alkalinity may also reveal human influences, but little has been done to evaluate the utility and necessity of this approach. Using data from 16 example sites in the Peace, Athabasca, and Slave Rivers in northern Alberta (but focusing on tributaries in Canada’s oil sands region) available from multiple regional, provincial, and national monitoring programs, we calculated residual conductivity and determined if it could identify the potential influence of human activity on streams in northern Alberta. To account for unequal sampling intervals within the compiled datasets, but also to include multiple covariates, we calculated residual conductivity using the Generalized Estimating Equation (GEE). The Pearson residuals of the GEEs were then plotted over time along with three smoothers (two locally weighted regressions and one General Additive Model) and a linear model to estimate temporal patterns remaining relative to known changes in human activity in the region or adjacent to the study locations. Although there are some inconsistencies in the results and large gaps in the data at some sites, many increases in residual conductivity correspond with known events in northern Alberta, including the potential influence of site preparation at oil sands mines, reductions in particulate emissions, mining, spills, petroleum coke combustion at one oil sands plant, and hydroelectric development in the Peace basin. Some differences in raw conductivity measurements over time were also indicated. Overall, these analyses suggest residual conductivity may identify broad influences of human activity and be a suitable tool for augmenting broad surveillance monitoring of water bodies alongside current approaches. However, some anomalous increases without apparent explanations were also observed suggesting changes in residual conductivity may also be well-suited for prompting additional and more detailed studies or analyses of existing data.
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Fu, ShuYing, WenDong Lin, XiNing Zhao, ShengJin Ge, and ZhangGang Xue. "Quantitative Relationships between Pulmonary Function and Residual Neuromuscular Blockade." BioMed Research International 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/9491750.
Повний текст джерелаАнотація:
Background. Neuromuscular blockade is a risk factor for postoperative respiratory weakness during the immediate postoperative period. The quantitative relationships between postoperative pulmonary-function impairment and residual neuromuscular blockade are unknown. Methods. 113 patients who underwent elective laparoscopic cholecystectomy were enrolled in this study. They all had a pulmonary-function test (PFT) during the preoperative evaluation. Predictive values based on demographic data were also recorded. The train-of-four ratio (TOFR) was recorded at the same time as the PFT and at every 5 minutes in the qualified 98 patients in the postanesthesia care unit (PACU). We analyzed the degree of PFT recovery when the TOFR had recovered to different degrees. Results. There was a significant difference (P<0.05) between the preoperative baseline value and the postoperative forced vital capacity at each TOFR point, except at a TOFR value of 1.1. There was also a significant difference (P<0.05) between the preoperative baseline value and the postoperative peak expiratory flow at each TOFR point. Conclusions. Postoperative residual neuromuscular blockade was common (75.51%) after tracheal extubation, and pulmonary function could not recover to an acceptable level (85% of baseline value), even if TOFR had recovered to 0.90. Trial Registration. Chinese Clinical Trial Register is ChiCTR-OOC-15005838.
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Eleonsky, Sviatoslav, Vladimir Pisarev, Mikhail Zajtsev, Mikhail Zichenkov, and Marat Abdullin. "Residual stresses near cold-expanded hole at different stages of high-cycle fatigue by crack compliance data." Frattura ed Integrità Strutturale 15, no. 56 (March 28, 2021): 171–96. http://dx.doi.org/10.3221/igf-esis.56.14.
Повний текст джерелаАнотація:
Experimental method for a characterization of high-cycle fatigue evolution of residual stress near cold-expanded hole is developed and implemented. The technique is based on simultaneous measurements of deformation response to narrow notch, inserted in residual stress field, on opposite specimen’s faces by electronic speckle-pattern interferometry (ESPI). Two-side measurements of notch opening displacements are performed when a single notch, emanating from cold-expanded hole edge, is inserted. The transition from in-plane displacement component to residual stress intensity factor (SIF) values follows from the relationships of modified version of the crack compliance method. The approach provides a difference in residual stress values referred to mandrel entrance and exit surface. Notches are inserted at different stages of low-cycle fatigue without applying external load. The results obtained describe fine nuances of residual stress evolution, which cannot be considered as monotonic relaxation.
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Cartocci, Nicholas, Marcello R. Napolitano, Francesco Crocetti, Gabriele Costante, Paolo Valigi, and Mario L. Fravolini. "Data-Driven Fault Diagnosis Techniques: Non-Linear Directional Residual vs. Machine-Learning-Based Methods." Sensors 22, no. 7 (March 29, 2022): 2635. http://dx.doi.org/10.3390/s22072635.
Повний текст джерелаАнотація:
Linear dependence of variables is a commonly used assumption in most diagnostic systems for which many robust methodologies have been developed over the years. In case the system nonlinearities are relevant, fault diagnosis methods, relying on the assumption of linearity, might potentially provide unsatisfactory results in terms of false alarms and missed detections. In recent years, many authors have proposed machine learning (ML) techniques to improve fault diagnosis performance to mitigate this problem. Although very powerful, these techniques require faulty data samples that are representative of any fault scenario. Additionally, ML techniques suffer from issues related to overfitting and unpredictable performance in regions which are not fully explored in the training phase. This paper proposes a non-linear additive model to characterize the non-linear redundancy relationships among the system signals. Using the multivariate adaptive regression splines (MARS) algorithm, these relationships are identified directly from the data. Next, the non-linear redundancy relationships are linearized to derive a local time-dependent fault signature matrix. The faulty sensor can then be isolated by measuring the angular distance between the column vectors of the fault signature matrix and the primary residual vector. A quantitative analysis of fault isolation and fault estimation performance is performed by exploiting real data from multiple flights of a semi-autonomous aircraft, thus allowing a detailed quantitative comparison with state-of-the-art machine-learning-based fault diagnosis algorithms.
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Bandyopadhyay, S. K., and R. De. "Nitrogen relationships and residual effects of intercropping sorghum with legumes." Journal of Agricultural Science 107, no. 3 (December 1986): 629–32. http://dx.doi.org/10.1017/s0021859600069793.
Повний текст джерелаАнотація:
SUMMARYIntercropped with legumes, sorghum removed more N from the growing medium than when grown alone. 16N data showed that out of the total N removed by sorghum in a sorghum + mung mixture 18·1% was derived from the fertilizer urea and 81·9% came from the soil pool; the latter included 21·9 % N derived from current fixation by the legumes. When grown alone sorghum plants derived 18·6 % N from urea and 81·4 % from the soil.The yield of wheat grown in sequence was 5·13 t/ha after a previous sole crop of mung and 3·47 t/ha after sorghum. The yield of wheat after sole crops of legume was greater than after their mixture with sorghum. The latter was, however, greater than its yield after sole sorghum.The economic optimum rate of N required after wheat, computed from an experiment with several rates of applied N on an adjacent plot, was 124 and 105 kg N/ha at expected yields of 5·2 and 4·5 t/ha of wheat respectively. By interpolation the relative yield advantage from sole legumes ranged between 28 and 68 kg N/ha in 1982–3 and was more than 90 kg N/ha in the next year. These advantages from legume + non-legume mixtures equalled 12–17 kg N/ha applied to wheat, in addition to 50 kg N/ha applied uniformly to the sequential crop of wheat.
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Northwood, Derek O., Lily He, Erin Boyle, and Randy J. Bowers. "Retained Austenite - Residual Stress - Distortion Relationships in Carburized SAE 6820 Steel." Materials Science Forum 539-543 (March 2007): 4464–69. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.4464.
Повний текст джерелаАнотація:
SAE 8620 steel is typically used in the carburized condition for powertrain applications in the automotive industry, e.g. gears, roller bearings, camshafts. Such steels always contain retained austenite to varying degrees in the as-hardened and also in the tempered microstructures. As well as retained austenite, heat treatment can produce residual stresses, which lead to distortion (size and shape). The intent of this study was to investigate the effect of heat treatment parameters on the amount of retained austenite, residual stress and distortion in carburized SAE 8620 steel. A specially designed specimen, the Navy C-ring, was used for this study. The steel was first normalized prior to machining the Navy C-ring specimens. The specimens were then heat treated by carburizing at 927°C or 954°C (1700°F or 1750°F) at four levels of carbon potential (0.9, 1.0, 1.1, 1.2) followed by oil quenching and tempering at either 149°C or 177°C (300°F or 350°F). The distortion of the C-ring was evaluated by dimensional measurements of the inner diameter, outer diameter, gap width and thickness for size distortion, as well as flatness, cylindricity and roundness for shape distortion. X-ray diffraction (XRD) techniques were used to determine the residual stress and the amount of retained austenite. The amount of retained austenite was also measured by optical metallography. The amount of retained austenite and the residual stress increased with increasing carburizing temperature and carbon potential and decreased upon tempering. There was not a significant further reduction in the amount of retained austenite and residual stress when the tempering temperature was increased from 149°C to 177°C. Distortion was influenced by both the amount of retained austenite and the magnitude of the residual stress. With increasing retained austenite/residual stress, the distortion became more serious. Based on the distortion data for 3 parameters (OD, gap width and flatness) for the quenched and tempered specimens, the amount of retained austenite for minimum distortion was approximately 25%.
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Reist, James D. "An empirical evaluation of coefficients used in residual and allometric adjustment of size covariation." Canadian Journal of Zoology 64, no. 6 (June 1, 1986): 1363–68. http://dx.doi.org/10.1139/z86-203.
Повний текст джерелаАнотація:
Univariate computation of residuals or allometric variates should be used to estimate the shape of body parts of ectothermic vertebrates. For studies involving more than one group, three types of relationships may be used to calculate the slopes or allometric coefficients necessary for computing the shape variate: pooled group, common-within groups, and individual-within groups. For both residuals and allometric variates, the pooled and common-within groups coefficients resulted in similar estimates of shape when there was no between-group heterogeneity in relationships. Within-group coefficients resulted in quite different estimates of shape. Heterogeneity of slopes or allometric coefficients resulted in different estimates of shape for the same individual for pooled common-within and within-groups data. Such differences in the shape variates were cumulative in subsequent analyses such that considerably different biological interpretations of group interrelationships resulted. Thus, if any between-group heterogeneity exists in regression or allometric relationships, it is imperative that shape be estimated from the common-within groups relationship.
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Beyer, Ann-Kristin, Maja Wiest, and Susanne Wurm. "There Is Still Time to Be Active: Self-Perceptions of Aging, Physical Activity, and the Role of Perceived Residual Lifetime Among Older Adults." Journal of Aging and Physical Activity 27, no. 6 (December 1, 2019): 807–15. http://dx.doi.org/10.1123/japa.2018-0380.
Повний текст джерелаАнотація:
Self-perceptions of aging (SPA) are a resource in later life. As aging is accompanied with perceptions of the finitude of life, it is assumed that perceived residual lifetime may play a role in the relationship between SPA and health behavior. Among older adults aged 65 years and older, the present study tested whether the relationships between gain- and loss-related SPA and two kinds of physical activity are moderated by perceived residual lifetime. Data were based on 2.367 participants over a 3-year period. Participants with less gain-related SPA were less likely to walk on a regular basis; however, a longer residual lifetime compensated for this negative effect. In addition, participants did sports more often if they not only held less loss-related SPA but also perceived a longer residual lifetime. These results emphasize the importance of perceived residual lifetime in health promotion interventions targeting physical activity in older adults.
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Leaman, D. E., and R. G. Richardson. "Production of a residual gravity field map for Tasmania and some implications." Exploration Geophysics 20, no. 2 (1989): 181. http://dx.doi.org/10.1071/eg989181.
Повний текст джерелаАнотація:
The substantial gravity data base in Tasmania has been used to formulate a regional crustal model. This was derived by array modelling techniques for geological sources of crustal scale. A simultaneous solution for mantle, basement and granite forms was created by this means within a framework of realistic and internally consistent assumptions. The regional field derived from this geological model (including the ocean basins) is not dependent on any filtering or smoothing procedure and thus the magnitude and sign of any residuals is absolute. The residual map was produced by removing the effect of the crustal model at individual data points. The resultant map enables detailed and reliable modelling of upper crustal features as well as revealing crustal character hitherto concealed beneath post Carboniferous cover. An important example of the value of the residual separation is shown by the structural relationships exposed in NE Tasmania which involve gold mineralisation.
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Meskenas, Adas, Viktor Gribniak, Gintaris Kaklauskas, Aleksandr K. Arnautov, and Arvydas Rimkus. "SIMPLIFIED TECHNIQUE FOR CONSTITUTIVE ANALYSIS OF SFRC." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 20, no. 3 (June 9, 2014): 446–53. http://dx.doi.org/10.3846/13923730.2014.909882.
Повний текст джерелаАнотація:
Steel fibre reinforced concrete (SFRC) has become widespread material in areas such as underground shotcrete structures and industrial floors. However, due to the absence of material models of SFRC reliable for numerical analysis, application fields of this material are still limited. Due to interaction of concrete with fibres, a cracked section is able to carry a significant portion of tensile stresses, called the residual stresses. In present practices, residual stresses used for strength, deflection and crack width analysis are quantified by means of standard tests. However, interpretation of these test results is based on approximation using empirically deduced relationships, adequacy of which might be insufficient for an advanced numerical analysis. Based on general principles of material mechanics, this paper proposes a methodology for determination of residual stress-crack opening relationships using experimental data of three-point bending tests. To verify the constitutive analysis results, a numerical modelling is utilised employing a nonlinear finite element analysis program ATENA. Simulated load-crack width relationships and moment-curvature diagrams were compared with the experimental data by validating adequacy of the derived constitutive models.
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Santos, M. Begoña, Rafael González-Quirós, Isabel Riveiro, José M. Cabanas, Carmela Porteiro, and Graham J. Pierce. "Cycles, trends, and residual variation in the Iberian sardine (Sardina pilchardus) recruitment series and their relationship with the environment." ICES Journal of Marine Science 69, no. 5 (December 13, 2011): 739–50. http://dx.doi.org/10.1093/icesjms/fsr186.
Повний текст джерелаАнотація:
Abstract Santos, M. B., González-Quirós, R., Riveiro, I., Cabanas, J. M., Porteiro, C., and Pierce, G. J. 2012. Cycles, trends, and residual variation in the Iberian sardine (Sardina pilchardus) recruitment series and their relationship with the environment. – ICES Journal of Marine Science, 69: 739–750. Recruitment variability is an important component of the dynamics of Iberian sardine (Sardine pilchardus). Since 2006, poor recruitment has led to a decrease in stock biomass, the latest in a series of such crises for sardine fisheries. Understanding the mechanisms behind recruitment fluctuations has been the objective of many previous studies, and various relationships between recruitment and environmental variables have been proposed. However, such studies face several analytical challenges, including short time-series and autocorrelated data. A new analysis of empirical relationships with environmental series is presented, using statistical methods designed to cope with these issues, including dynamic factor analysis, generalized additive models, and mixed models. Relationships are identified between recruitment and global (number of sunspots), regional (NAOAutumn), and local [winter wind strength, sea surface temperature (SST), and upwelling] environmental variables. Separating these series into trend and noise components permitted further investigation of the nature of the relationships. Whereas the other three environmental variables were related to the trend in recruitment, SST was related to residual variation around the trend, providing stronger evidence for a causal link, possible mechanisms for which are discussed. After the removal of trend and cyclic components, residual variation in recruitment is also weakly related to the previous year's spawning-stock biomass.
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Nicoletto, G. "Theoretical fringe analysis for a coherent optics method of residual stress measurement." Journal of Strain Analysis for Engineering Design 23, no. 4 (October 1, 1988): 169–78. http://dx.doi.org/10.1243/03093247v234169.
Повний текст джерелаАнотація:
In this paper, the theoretical relationships between relieved in-plane displacements and residual stresses, which are needed for data reduction in a moiré interferometric version of hole drilling method, are obtained. The analysis includes the case of linearly varying biaxial stresses. The theoretical relationships are then used for generating on a computer the corresponding moiré interferometric fringe patterns thus simulating the experimental response under known loading conditions. Various effects due to the degree of residual stress biaxiality, the strength of the linear stress term, the direction of sensitivity of the moiré grid, and the value of the Poisson's ratio are illustrated.
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Biondini, Riccardo, Yan-Xia Lin, and Michael Mccrae. "A case study of the residual-based cointegration procedure." Journal of Applied Mathematics and Decision Sciences 7, no. 1 (January 1, 2003): 29–48. http://dx.doi.org/10.1155/s1173912603000038.
Повний текст джерелаАнотація:
The study of long-run equilibrium processes is a significant component of economic and finance theory. The Johansen technique for identifying the existence of such long-run stationary equilibrium conditions among financial time series allows the identification of all potential linearly independent cointegrating vectors within a given system of eligible financial time series. The practical application of the technique may be restricted, however, by the pre-condition that the underlying data generating process fits a finite-order vector autoregression (VAR) model with white noise. This paper studies an alternative method for determining cointegrating relationships without such a pre-condition. The method is simple to implement through commonly available statistical packages. This ‘residual-based cointegration’ (RBC) technique uses the relationship between cointegration and univariate Box-Jenkins ARIMA models to identify cointegrating vectors through the rank of the covariance matrix of the residual processes which result from the fitting of univariate ARIMA models. The RBC approach for identifying multivariate cointegrating vectors is explained and then demonstrated through simulated examples. The RBC and Johansen techniques are then both implemented using several real-life financial time series.
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Grandey, B. S., P. Stier, and T. M. Wagner. "Investigating relationships between aerosol optical depth and cloud fraction using satellite, aerosol reanalysis and general circulation model data." Atmospheric Chemistry and Physics Discussions 12, no. 11 (November 29, 2012): 30805–23. http://dx.doi.org/10.5194/acpd-12-30805-2012.
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Abstract. Strong positive relationships between cloud fraction (fc) and aerosol optical depth (τ) have been reported. Data retrieved from the MODerate resolution Imaging Spectroradiometer (MODIS) instrument show positive fc–τ relationships across most of the globe. However, these relationships are not necessarily due to cloud–aerosol interactions. Using state of the art Monitoring Atmospheric Composition and Climate (MACC) reanalysis-forecast τ data, which should be less affected by retrieval artifacts, it is demonstrated that a large part of the observedfc–τ signal may be due to cloud contamination of satellite-retrieved τ. For longer MACC forecast time-steps of 24 h, which likely contain less residual cloud contamination, some negative fc–τ relationships are found. ECHAM5-HAM general circulation model (GCM) simulations further demonstrate that positive fc–τ relationships may arise due to covariation with relative humidity. Widespread negative simulated fc–τ relationships in the tropics are shown to arise due to scavenging of aerosol by precipitation. Wet scavenging events are likely poorly sampled in satellite-retrieved data. Quantifying the role of wet scavenging, and assessing GCM representations of this important process, remains a challenge for future observational studies of aerosol–cloud–precipitation interactions.
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Benway, Nina R., Kelly Garcia, Elaine Hitchcock, Tara McAllister, Megan C. Leece, Qiu Wang, and Jonathan L. Preston. "Associations Between Speech Perception, Vocabulary, and Phonological Awareness Skill in School-Aged Children With Speech Sound Disorders." Journal of Speech, Language, and Hearing Research 64, no. 2 (February 17, 2021): 452–63. http://dx.doi.org/10.1044/2020_jslhr-20-00356.
Повний текст джерелаАнотація:
Purpose Prior studies report conflicting descriptions of the relationships between phonological awareness (PA), vocabulary, and speech perception in preschoolers with speech disorders. This study sought to determine the nature of these relationships in a sample of school-aged children with residual speech sound errors affecting /ɹ/. Method Participants included 110 children aged 7;0–17;4 (years;months) with residual errors impacting /ɹ/. Data on perceptual acuity and perceptual bias in an /ɹ/ identification task, receptive vocabulary, and PA were obtained. A theoretically and empirically motivated path model was constructed with vocabulary mediating the relationship between two measures of speech perception and PA. Model parameters were determined through maximum likelihood estimation with standard errors that were robust to nonnormality. Monte Carlo simulation was used to examine achieved power at the current sample size. Results The saturated path model explained 19% of the variance in PA. The direct path between age-adjusted perceptual acuity and PA was significant, as was the direct path between vocabulary and PA. Contrary to our hypothesis, there was no evidence in the current sample that vocabulary skill mediated the relationship between speech perception and PA. Each individual path was adequately powered at the current sample size. Conclusions The overall model provided evidence for a continued relationship between speech perception, measured by perceptual acuity of the sound in error, and PA in school-aged children with residual speech errors. Thus, measures of speech perception remain relevant to the assessment of school-aged children and adolescents in this population. Supplemental Material https://doi.org/10.23641/asha.13641275
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Dollfus, S., M. Petit, JF Menard, and P. Lesieur. "Schizophrenia: comparison of 13 diagnostic systems in a cross-sectional study1." European Psychiatry 8, no. 1 (1993): 7–13. http://dx.doi.org/10.1017/s0924933800001498.
Повний текст джерелаАнотація:
SummaryThe concordance and degree of overlap between 13 diagnostic systems for schizophrenia, including the five European systems of Berner, Bleuler, Langfeldt, Pull and Schneider, were evaluated in a cross-sectional study (N = 51) taking the phase of illness (acute or residual) into account. The diagnostic assessments were processed by computer using a 183-item standardised checklist and a data-processing program in GW-Basic language. The inter-rater reliability, as assessed by Kappa coefficient, was good to excellent for each diagnostic system established by this method (K from 0.5 to 1). When comparing the concordance between pairs of 13 diagnostic systems for schizophrenia in acute and residual phase groups, results showed that only two significant relationships were not influenced by the phase of illness (Carpenter x RDC; Catego x Schneider), while 24 were. These included only two relationships in the acute group (Carpenter Catego; Carpenter Schneider) and 22 links between pairs of systems in the residual group. In the acute group, no diagnosis of schizophrenia, including duration criteria such as those of DSM III-R, Feighner, Langfeldt, Pull and RDC, was linked to other systems. In the residual group, the operational systems such as Catego, DSM III-R, Feighner, Newhaven, Pull and RDC had more than five relationships with the other systems whereas the non-operational systems of Bleuler, ICD9, Langfeldt and Schneider had less than four relationships with the others. Except Pull's criteria, the European diagnostic systems, in particular Berner's and Bleuler's, seemed to differ from the others because of the few relationships displayed. The results underline the importance of taking the phase of illness into account when comparing between studies utilizing different diagnostic systems for schizophrenia. They also show the relationships between European and international diagnostic systems, insufficiently established so far.
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Moya-Laraño, J., and G. Corcobado. "Plotting partial correlation and regression in ecological studies." Web Ecology 8, no. 1 (June 4, 2008): 35–46. http://dx.doi.org/10.5194/we-8-35-2008.
Повний текст джерелаАнотація:
Abstract. Multiple regression, the General linear model (GLM) and the Generalized linear model (GLZ) are widely used in ecology. The widespread use of graphs that include fitted regression lines to document patterns in simple linear regression can be easily extended to these multivariate techniques in plots that show the partial relationship of the dependent variable with each independent variable. However, the latter procedure is not nearly as widely used in ecological studies. In fact, a brief review of the recent ecological literature showed that in ca. 20% of the papers the results of multiple regression are displayed by plotting the dependent variable against the raw values of the independent variable. This latter procedure may be misleading because the value of the partial slope may change in magnitude and even in sign relative to the slope obtained in simple least-squares regression. Plots of partial relationships should be used in these situations. Using numerical simulations and real data we show how displaying plots of partial relationships may also be useful for: 1) visualizing the true scatter of points around the partial regression line, and 2) identifying influential observations and non-linear patterns more efficiently than using plots of residuals vs. fitted values. With the aim to help in the assessment of data quality, we show how partial residual plots (residuals from overall model + predicted values from the explanatory variable vs. the explanatory variable) should only be used in restricted situations, and how partial regression plots (residuals of Y on the remaining explanatory variables vs. residuals of the target explanatory variable on the remaining explanatory variables) should be the ones displayed in publications because they accurately reflect the scatter of partial correlations. Similarly, these partial plots can be applied to visualize the effect of continuous variables in GLM and GLZ for normal distributions and identity link functions.
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Park, No-Wook. "Spatial Downscaling of TRMM Precipitation Using Geostatistics and Fine Scale Environmental Variables." Advances in Meteorology 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/237126.
Повний текст джерелаАнотація:
A geostatistical downscaling scheme is presented and can generate fine scale precipitation information from coarse scale Tropical Rainfall Measuring Mission (TRMM) data by incorporating auxiliary fine scale environmental variables. Within the geostatistical framework, the TRMM precipitation data are first decomposed into trend and residual components. Quantitative relationships between coarse scale TRMM data and environmental variables are then estimated via regression analysis and used to derive trend components at a fine scale. Next, the residual components, which are the differences between the trend components and the original TRMM data, are then downscaled at a target fine scale via area-to-point kriging. The trend and residual components are finally added to generate fine scale precipitation estimates. Stochastic simulation is also applied to the residual components in order to generate multiple alternative realizations and to compute uncertainty measures. From an experiment using a digital elevation model (DEM) and normalized difference vegetation index (NDVI), the geostatistical downscaling scheme generated the downscaling results that reflected detailed characteristics with better predictive performance, when compared with downscaling without the environmental variables. Multiple realizations and uncertainty measures from simulation also provided useful information for interpretations and further environmental modeling.
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Busso, Thierry, Pei-Ji Liang, and Peter A. Robbins. "Breath-to-breath relationships between respiratory cycle variables in humans at fixed end-tidal Pco 2 and Po 2." Journal of Applied Physiology 81, no. 5 (November 1, 1996): 2287–96. http://dx.doi.org/10.1152/jappl.1996.81.5.2287.
Повний текст джерелаАнотація:
Busso, Thierry, Pei-Ji Liang, and Peter A. Robbins.Breath-to-breath relationships between respiratory cycle variables in humans at fixed end-tidal Pco 2 and Po 2. J. Appl. Physiol. 81(5): 2287–2296, 1996.—This study examined the statistical properties of breath-to-breath variations in the inspiratory and expiratory volumes and times during rest and light exercise. Sixty data sets were analyzed. Initial data and residuals after fitting time-series models were examined for 1) sustained periodicities with use of spectral analysis, 2) temporal changes in signal power with use of evolutionary spectral analysis, and 3) auto- and cross correlations with use of a portmanteau test. The major findings were as follows: 1) no sustained periodic components were detected; 2) temporal changes in signal power were normally present, but these did not affect significantly the results from time-series modeling; 3) for all variables, a simple autoregressive moving average (ARMA) AR1MA1 model generally described the autocorrelation; 4) considerable cross correlation remained between residuals from the AR1MA1 model; 5) relationships between variables could be described by using a multivariate time-series model; 6) residual fluctuations in end-tidal Pco 2 had little influence; and 7) responses were broadly similar between rest and exercise, although some quantitative differences were found. The multivariate model provides a description of the structure of the interrelationships between cycle variables in a quantitative and a qualitative form.
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Roe, J., A. Baker, and J. Bridgeman. "Relating organic matter character to trihalomethanes formation potential: a data mining approach." Water Supply 8, no. 6 (December 1, 2008): 717–23. http://dx.doi.org/10.2166/ws.2008.150.
Повний текст джерелаАнотація:
The removal of natural organic matter (NOM) during water treatment is becoming more important for all water utilities in the UK, as a result of tightened regulatory standards for trihalomethanes (THM), disinfection by-products (DBP) formed when residual organics react with chlorine. This paper considers the spatial and temporal variability of raw and clarified water arising from 16 surface water treatment works in the Midlands region of the UK. A wide range of investigation techniques are applied in order to develop effective strategies for the treatment of NOM-rich water. For the first time, rigorous data mining techniques are applied to a major dataset in order to examine potential inter-relationships between a wide range of quality parameters including, inter alia, total organic carbon (TOC), UV254, coagulation pH, resin fractionation (hydrophilic acids (HPIA), hydrophobic acids (HPOA), hydrophilic non-acids (HPINA)) and total THM formation potential (TTHMFP). This paper focuses on the use of principal component analysis (PCA) to develop robust algorithms for the prediction of TOC removal and hence THM formation. Results show that raw water characteristics can be categorised into three main types, according to their HPOA content and specific ultraviolet absorbance (SUVA.). PCA identified possible THMFP precursors, according to raw water type verified by strong statistical relationships.
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Lancaster, Phillip A. "PSIV-2 Evaluation of Relationship Between Feed Efficiency Traits and Energy Metabolism Using Comparative Slaughter Studies in Growing and Finishing Cattle." Journal of Animal Science 99, Supplement_1 (May 1, 2021): 214–15. http://dx.doi.org/10.1093/jas/skab054.352.
Повний текст джерелаАнотація:
Abstract There is uncertainty whether feed efficiency traits are related to energetic efficiency. The objective of this study was to utilize comparative slaughter data to evaluate the relationships of feed efficiency traits with maintenance energy requirements (MEm) and efficiency of metabolizable energy (ME) use for maintenance (km) and gain (kg). Published data were compiled (31 studies, 214 treatment means) on metabolizable energy intake (MEI) and composition of empty body gain in growing cattle. Data analyses were performed using R statistical software considering each treatment mean as an independent experimental unit. Assuming fasting heat production (FHP) varies only due to empty body protein (EBP) composition, it was computed as 295 kcal/kg EBP.75. MEm, km, and kg were computed from the nonlinear relationship between heat production and MEI. Residual intake (lower is more efficient) was computed as the residual from linear regression of MEI on EBW and EBW gain (RMEI) or MEI on EBP, retained energy as protein and retained energy as fat (RMEIc). Residual gain (higher is more efficient) was computed as the residual from linear regression of EBW gain on EBW and MEI (REBG) or retained energy on EBP and MEI (RRE). MEI was positively correlated with RMEI (0.46) and RMEIc (0.44), and EBW gain was correlated with REBG (0.58) and RRE (0.39). FHP was correlated with RMEIc (-0.25). MEm was weakly correlated with RMEI (0.19), RMEIc (0.22), and REBG (-0.26), but strongly correlated with RRE (-0.51). km was moderately correlated with RMEI (-0.35), but strongly correlated with REBG (0.49), RMEIc (-0.59), and RRE (0.79). kg was strongly correlated with RMEI (-0.69), REBG (0.47), RMEIc (-0.89), and RRE (0.70). Correlations among feed efficiency traits were strong (>±0.48). In conclusion, feed efficiency traits using retained energy as the dependent variable had stronger correlations with maintenance energy requirements than those using feed intake as the dependent variable.
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Ghanbarian-Alavijeh, B., and A. M. Liaghat. "Evaluation of soil texture data for estimating soil water retention curve." Canadian Journal of Soil Science 89, no. 4 (August 1, 2009): 461–71. http://dx.doi.org/10.4141/cjss08066.
Повний текст джерелаАнотація:
The soil water retention curve (SWRC) is one of the basic characteristics used in determining soil hydraulic properties, including unsaturated hydraulic conductivity. As its measurement is time consuming and difficult, much effort has been expended to develop indirect methods, such as pedotransfer functions and empirical relationships, to estimate SWRC. In this study, three methods were evaluated based on estimation of retention models parameters and, consequently, the soil water retention curve. For this purpose, soil data collected from three data bases, totaling 72 soil samples with 11 different textures, were used in this study. The statistical parameters such as: MR (mean of residual), RE (relative error), RMSE (root mean square error), AIC (Akaike’s information criterion) and GMER (geometric mean error ratio) showed that the Saxton et al. (1986) method estimates the soil water retention curve better than the other methods.Key words: Pedotransfer function, soil texture, soil water retention curve
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Hartmann, Sönke, Lydia Pedoth, Cristina Dalla Torre, and Stefan Schneiderbauer. "Beyond the Expected—Residual Risk and Cases of Overload in the Context of Managing Alpine Natural Hazards." International Journal of Disaster Risk Science 12, no. 2 (January 22, 2021): 205–19. http://dx.doi.org/10.1007/s13753-020-00325-3.
Повний текст джерелаАнотація:
AbstractStructural protection measures are designed to protect the population and infrastructure against natural hazards up to a specific predefined protection goal. Extreme events with intensities that exceed the capacity of these protection structures are called “cases of overload” and are associated with “residual risks” that remain after the implementation of protection measures. In order to address residual risks and to reduce the damages from overload events, a combination of structural protection measures with additional, nonstructural measures is required. Based on data collected through a literature review, a questionnaire survey, expert interviews, and an expert workshop we highlight the status quo as well as key challenges of dealing with residual risks and cases of overload in Alpine countries in the context of geohydrological hazards and gravitational mass movements. We present a holistic conceptual framework that describes the relationships of residual risks, cases of overload, and protection goals in the context of both risk governance and integrated risk management. This framework is valuable for decision makers aiming at an improved management of natural hazards that takes adequate account of residual risk and cases of overload in Alpine countries and mountain areas worldwide.
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Chuang, Ming-Lung, and I.-Feng Lin. "Investigating the relationships among lung function variables in chronic obstructive pulmonary disease in men." PeerJ 7 (October 1, 2019): e7829. http://dx.doi.org/10.7717/peerj.7829.
Повний текст джерелаАнотація:
Background In patients with chronic obstructive pulmonary disease (COPD), the independent contributions of individual lung function variables to outcomes may be lower when they are modelled together if they are collinear. In addition, lung volume measurements may not be necessary after spirometry data have been obtained. However, these hypotheses depend on whether forced vital capacity (FVC) can predict total lung capacity (TLC). Moreover, the definitions of hyperinflation and air trapping according to lung function variables overlap and need be clarified. Therefore, the aim of this study was to evaluate the relationships among various lung function parameters to elucidate these issues. Methods Demographic data and 26 parameters of full lung function were measured in 94 men with COPD and analyzed using factor and correlation analyses. Results Factor analysis revealed five latent factors. Inspiratory capacity (IC)/TLC and residual volume (RV)/TLC were most strongly correlated with all other lung volumes. IC/TLC, RV/TLC, and functional residual capacity (FRC)/TLC were collinear and were potential markers of air trapping, whereas TLC%, FRC%, and RV% were collinear and were potential markers of hyperinflation. RV/TLC >0.4 (or IC/TLC <0.4) was comparable with the ratio of forced expiratory volume in one second (FEV1) and FVC <0.7. FVC% and FEV1% were poorly correlated with TLC%. The correlation study showed that TLC%, RV/TLC, and FEV1% could be used to represent individual latent factors for hyperinflation, air trapping, inspiration, expiration, and obstruction. Combined with diffusion capacity%, these four factors could be used to represent comprehensive lung function. Conclusions This study identified collinear relationships among individual lung function variables and thus selecting variables with close relationships for correlation studies should be performed with caution. This study also differentiated variables for air trapping and lung hyperinflation. Lung volume measurements are still required even when spirometry data are available. Four out of 26 lung function variables from individual latent factors could be used to concisely represent lung function.
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Dos Santos, Mario Lima, Richard Pinheiro Rodrigues, Michael Douglas Roque Lima, Walmer Bruno Rocha Martins, Beatriz Cordeiro Costa, and Patricia Mie Suzuki. "Hypsometric models for a clonal plantation of Tectona grandis Linn F. subjected to selective thinning." REVISTA AGRO@MBIENTE ON-LINE 13 (May 15, 2019): 35. http://dx.doi.org/10.18227/1982-8470ragro.v13i0.5292.
Повний текст джерелаАнотація:
At a moment when the importance of planted forests in the Amazon region is increasing, hypsometric models become highly relevant tools as they allow monitoring of and planning for tree plantations in a way that is practical and economic for the producer. Thus, the objective of the current study was to select and adjust a model of hypsometric relationships for a clonal plantation of Tectona grandis Linn F., submitted to selective
thinning, located in Capitão Poço municipality, Pará state, Brazil. Data were collected from permanent plots in five-year-old stands using the fixed area method and systematic process. The best adjusted model was selected with an adjusted determination coefficient (R²aj.%), residual standard deviation of the percentage estimate (Syx%), recalculated residual standard error (Syxr%), diagnosis of distribution of residuals as a percentage and
the Percent Average Deviation (PAD%). Hyperbolic models 2 and 3 had the highest determination coefficients (83.42 and 83.40%) and lowest PAD (-0.006 and -0.154%). The polynomial (1) and hyperbolic models (2 and 3) showed the smallest errors in related to the estimates. Model 2 (hyperbolic) was found to generate the
best estimate of total T. grandis clonal plantation height. Use of this hypsometric model will allow a significant
reduction of costs and time in forest inventory studies.
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Khalilisamani, Nima, Peter Campbell Thomson, Herman Willem Raadsma, and Mehar Singh Khatkar. "Estimating heritability using family-pooled phenotypic and genotypic data: a simulation study applied to aquaculture." Heredity 128, no. 3 (January 31, 2022): 178–86. http://dx.doi.org/10.1038/s41437-022-00502-8.
Повний текст джерелаАнотація:
AbstractEstimating heritability based on individual phenotypic and genotypic measurements can be expensive and labour-intensive in commercial aquaculture breeding. Here, the feasibility of estimating heritability using within-family means of phenotypes and allelic frequencies was investigated. Different numbers of full-sib families and family sizes across ten generations with phenotypic and genotypic information on 10 K SNPs were analysed in ten replicates. Three scenarios, representing differing numbers of pools per family (one, two and five) were considered. The results showed that using one pool per family did not reliably estimate the heritability of family means. Using simulation parameters appropriate for aquaculture, at least 200 families of 60 progeny per family divided equally in two pools per family was required to estimate the heritability of family means effectively. Although application of five pools generated more within- and between- family relationships, it reduced the number of individuals per pool and increased within-family residual variation, hence, decreased the heritability of family means. Moreover, increasing the size of pools resulted in increasing the heritability of family means towards one. In addition, heritability of family mean estimates were higher than family heritabilities obtained from Falconer’s formula due to lower intraclass correlation estimate compared to the coefficient of relationship.
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Khin, Aye Aye, Mei Peng Low, Moe Shwe Sin, Seethaletchumy Thambiah, and Soh Chong Yu. "Sustainability of Women’s Employment Rate for Malaysian Economic Development." Jurnal Institutions and Economies 13, no. 3 (July 1, 2021): 53–79. http://dx.doi.org/10.22452/ijie.vol13no3.3.
Повний текст джерелаАнотація:
This research paper develops a model for the sustainability of women’s employment rate in Malaysia’s economic development. This study examined annual data from 1982 to 2018, with 37 observations. A new econometric method was adopted to determine both short-run and long-run relationships among the variables using the Johansen Cointegration rank test, Vector Error Correction Method (VECM) with error correction model of cointegration equation. The VECM results revealed significant and positive short-term relationships between foreign direct investment, gross domestic product (GDP), and the negative short-term relationship of the lagged period of women’s employment rate to women employment rate (WER). The variables, GDP, education level, and women’s marital status are cointegrated and have a long-term relationship between WER in the cointegration equation. The Johansen Cointegration rank test also showed the existence of cointegration equations, and a long-term relationship between the variables. Eventually, the residual diagnosis, significant error term, and the performance of the model evaluation were found as satisfactory and valid. In short, this research paves the way for policymakers to construct a better policy for the future of women’s employment sustainability.
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Ge, Yan, and Gavin Gong. "North American Snow Depth and Climate Teleconnection Patterns." Journal of Climate 22, no. 2 (January 15, 2009): 217–33. http://dx.doi.org/10.1175/2008jcli2124.1.
Повний текст джерелаАнотація:
Abstract Snow–atmosphere relationships have been studied for nearly half a century, but the primary focus has been on snow extent variability, largely because of the relative scarcity of snow depth data. A recently released North American snow depth dataset, with extensive spatial coverage and multidecadal temporal duration, provides a new opportunity to compare snow depth–climate relationships with snow extent–climate relationships over North America. Robust concurrent lead and lag correlations are observed between snow depth and two major climate modes, the Pacific decadal oscillation (PDO) and the Pacific–North America (PNA) pattern, across North America and throughout the snow season. In contrast, snow extent exhibits a less coherent relationship with PDO and PNA except in late spring, which can be interpreted as a residual of the snow depth–climate mode relationship. A regional signature for the snow depth–PDO/PNA relationship is also identified, centered over interior central-western North America. Smaller scales mask the regional effect of PDO and PNA because of local snow depth variability, while larger continental scales exceed the regional domain of the climate mode teleconnections. Overall these results suggest that North American snow depth variability may have greater climatic causes and consequences than snow extent. Physical mechanisms that may be responsible for the observed snow depth–climate teleconnection patterns such as the surface energy balance, moisture transport, and atmospheric flow regimes are briefly discussed.
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MANSANO, Cleber Fernando Menegasso, Marcelo Maia PEREIRA, Nelson José PERUZZI, Beatrice Ingrid MACENTE, and Marta Verardino DE STÉFANI. "Nonlinear models for morphometric analysis in Bullfrog Tadpoles." Revista Brasileira de Saúde e Produção Animal 17, no. 2 (June 2016): 280–90. http://dx.doi.org/10.1590/s1519-99402016000200015.
Повний текст джерелаАнотація:
SUMMARY Biometric relationships are important to illustrate the growth of animals. When adjusted using nonlinear models, these relationships can provide important information that contributes to the improvement of breeding techniques. In this study, morphometric data as a function of weight obtained in four experiments involving bullfrog tadpoles were adjusted using Gompertz, Logistic, Von Bertalanffy and Brody nonlinear models and the best-fit model was determined. After fitting the parameters to the different models in each experiment, the models were compared based on confidence intervals (α = 0.05). The following criteria were used for selection of the best model: biological interpretation, residual mean square, coefficient of determination, graphic analysis, and number of iterations. Standard and total length data as a function of tadpole weight converged in the four models. The Logistic and Gompertz models had no biological interpretation for some datasets. The Brody model provided the lowest residual mean square and number of iterations for the variables studied in all experiments. The Brody relative growth rate (K) was lower for total length when compared to standard length, indicating a greater initial growth in standard length. The Brody model was the best to describe the growth in standard and total length of bullfrog tadpoles as a function of weight.
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Touitou, Florian, Flavie Tortereau, Lydie Bret, Nathalie Marty-Gasset, Didier Marcon, and Annabelle Meynadier. "Evaluation of the Links between Lamb Feed Efficiency and Rumen and Plasma Metabolomic Data." Metabolites 12, no. 4 (March 29, 2022): 304. http://dx.doi.org/10.3390/metabo12040304.
Повний текст джерелаАнотація:
Feed efficiency is one of the keystones that could help make animal production less costly and more environmentally friendly. Residual feed intake (RFI) is a widely used criterion to measure feed efficiency by regressing intake on the main energy sinks. We investigated rumen and plasma metabolomic data on Romane male lambs that had been genetically selected for either feed efficiency (line rfi−) or inefficiency (line rfi+). These investigations were conducted both during the growth phase under a 100% concentrate diet and later on under a mixed diet to identify differential metabolite expression and to link it to biological phenomena that could explain differences in feed efficiency. Nuclear magnetic resonance (NMR) data were analyzed using partial least squares discriminant analysis (PLS-DA), and correlations between metabolites’ relative concentrations were estimated to identify relationships between them. High levels of plasma citrate and malate were associated with genetically efficient animals, while high levels of amino acids such as L-threonine, L-serine, and L-leucine as well as beta-hydroxyisovalerate were associated with genetically inefficient animals under both diets. The two divergent lines could not be discriminated using rumen metabolites. Based on phenotypic residual feed intake (RFI), efficient and inefficient animals were discriminated using plasma metabolites determined under a 100% concentrate diet, but no discrimination was observed with plasma metabolites under a mixed diet or with rumen metabolites regardless of diet. Plasma amino acids, citrate, and malate were the most discriminant metabolites, suggesting that protein turnover and the mitochondrial production of energy could be the main phenomena that differ between efficient and inefficient Romane lambs.
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WANG, JIANMING, and FEIHONG LIU. "NUMERICAL SIMULATION FOR SHOT-PEENING BASED ON SPH-COUPLED FEM." International Journal of Computational Methods 08, no. 04 (November 20, 2011): 731–45. http://dx.doi.org/10.1142/s0219876211002782.
Повний текст джерелаАнотація:
In dealing with shot-peening simulation, existing literatures adopt finite element method (FEM), which establishes models of a single shot or several shots only, thus the effect of a large number of shots repeat impacting and the influence among adjacent shots are ignored. To overcome these disadvantages of FEM models, smoothed particle hydrodynamics (SPH)-coupled FEM modeling is presented, in which the shots are modeled by SPH particles and the target material is modeled by finite elements. The two parts interact through contact algorithm to simulate a number of shots impinging the target. Utilizing this model, a material model for shots is established, the relationships between compressive residual stress and peening frequencies, coverage, and velocities are analyzed. Steady compressive residual stress can be obtained by multiple peening; higher coverage can improve the compressive residual stress; faster velocities can induce greater and deeper maximum residual stress in target subsurface. The simulation results agree well with the existing experimental data. The study would not only provide a new powerful tool for the simulation of shot-peening process, but also be benefit to optimize the operating parameters.
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Gilayeneh, Victor S., and Sunday O. Nwaubani. "Evaluation of corrosion damage in reinforced concrete structures in terms of the rebar’s residual cross-section." MATEC Web of Conferences 364 (2022): 03006. http://dx.doi.org/10.1051/matecconf/202236403006.
Повний текст джерелаАнотація:
Corroding reinforced concrete structures are frequently assessed to determine the rate of corrosion propagation and the level of deterioration, which might compromise the structure’s reliability. Appropriate measures should be considered in deciding when and how to implement maintenance if safety must be ensured. However, the influential factor that governs or informs such decisions is corrosion damage quantification. Nonetheless, the current non-destructive methods of corrosion damage quantification often lead to ambiguity, and most do not evaluate corrosion damage in terms of the rebar’s cross-section loss, which is the primary effect of corrosion. To address these shortcomings, this paper proposes an effective, reliable, and less-complicated model for quantifying corrosion damage in reinforced concrete structures based on the cross-sectional area of the corroding bar. The study was conducted through experimental (laboratory-based) and numerical investigations of the relationship between the level of corrosion and the corrosion-induced crack width. Based on the investigations’ findings, appropriate relationships and essential parameters were identified, and the model was derived analytically. The derived model assesses corrosion damage in terms of the corroding bar’s residual cross-section and requires only a few input parameters, which can be obtained by non-destructive testing if not known. The model was tested against data obtained from the laboratory experiment and against other experimental and analytical data from the literature, and the results showed a good correlation.
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Nohrstedt, Daniel. "Networking and Crisis Management Capacity: A Nested Analysis of Local-Level Collaboration in Sweden." American Review of Public Administration 48, no. 3 (December 25, 2016): 232–44. http://dx.doi.org/10.1177/0275074016684585.
Повний текст джерелаАнотація:
Studies of how actors collaborate across organizational boundaries to prepare for and respond to extreme events have traditionally focused on describing network structure whereas fewer studies empirically investigate how network relationships influence crisis management capacities. Using survey data on crisis management work in Swedish municipalities, this study considers how the number of collaboration partners and venues for collaboration (networking) influence organizational goal attainment. Given managerial costs associated with increasingly complex collaboration networks, the study explores the diminishing returns hypothesis, which predicts a positive relationship between networking and goal attainment up to a certain point when payoffs do not increase. Results support a nonlinear relationship; networking at low levels had a positive effect on goal attainment whereas no relationship was found at moderate or high levels. To identify characteristics of collaboration conducive to performance, the study undertakes a comparative case study of two low-residual cases where the relationship between networking and performance follow the predicted nonlinear curve and one deviant case where high levels of networking had a positive effect on performance. The cases show that stable interpersonal relationships, clarification of the terms of collaboration, shared problem perceptions, and coordination of joint decision making constitute important assembly mechanisms for overcoming collective action problems.
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Dhifaoui, Zouhaier, and Faicel Gasmi. "Linear and nonlinear linkage of conditional stochastic volatility of interbank interest rates: Empirical evidence of the BRICS countries." BRICS Journal of Economics 2, no. 2 (July 30, 2021): 4–16. http://dx.doi.org/10.38050/2712-7508-2021-2-1.
Повний текст джерелаАнотація:
The purpose of this article is to detect a possible linear and nonlinear causal relationship between the conditional stochastic volatility of log return of interbank interest rates for the BRICS countries in the period from January 2015 to October 2018. To extract the volatility of the analyzed time series, we use a stochastic volatility model with moving average innovations. To test a causal relationship between the estimated stochastic volatilities, two steps are applied. First, we used the Granger causality test and a vector autoregressive model (VAR). Secondly, we applied the nonlinear Granger causality test to the raw data to explore a new nonlinear causal relationship between stochastic volatility time series, and also applied it to the residual of the VAR model to confirm the causality detected in the first step. This study demonstrates the existence of some unidirectional/bidirectional linear/nonlinear causal relationships between the studied stochastic volatility time series.
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Mu, Y., G. Vander Voort, M. K. Abo-Ismail, R. Ventura, J. Jamrozik, and S. P. Miller. "Genetic correlations between female fertility and postweaning growth and feed efficiency traits in multibreed beef cattle." Canadian Journal of Animal Science 96, no. 3 (September 1, 2016): 448–55. http://dx.doi.org/10.1139/cjas-2015-0175.
Повний текст джерелаАнотація:
With selection in beef cattle now incorporating feed efficiency, knowing the relationship with other traits is needed. Genetic relationships were estimated with an animal model in ASReml with a three-generation pedigree inclusive of 2882 animals. Multibreed data from two Ontario beef research farms with fertility traits were available on 1366 females and postweaning traits, including feed efficiency on 1297 individuals. Estimates of heritability for fertility traits were low to moderate ranging from 0.03 ± 0.01 for pregnancy rate to 0.21 ± 0.02 for gestation length, and postweaning traits were moderate to high with feed conversion ratio at 0.22 ± 0.06 to mid-metabolic weight at 0.89 ± 0.01. Both dry matter intake and mid-metabolic weight were genetically correlated with most fertility traits from −0.52 to 0.34. The genetic correlation between average daily gain and days to calving was moderately negative (–0.33 ± 0.16) as was residual feed intake with days to calving (–0.34 ± 0.17). Bigger cows with more feed intake and faster growth were more fertile, and residual feed intake had an unfavorable genetic correlation with days to calving, indicating that programs to select for feed efficiency should include fertility simultaneously in a selection index.
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Elhag, A. G., W. H. Elsawy, and D. N. Khalifa. "Impact of post-surgical residual tumor volume on local control in radiotherapy for maxillary sinus cancer." Journal of Clinical Oncology 25, no. 18_suppl (June 20, 2007): 16518. http://dx.doi.org/10.1200/jco.2007.25.18_suppl.16518.
Повний текст джерелаАнотація:
16518 Background: The aim was to study the influence of post-surgical gross residual tumor volume on local control of maxillary sinus cancer treated with radiotherapy combined with debulking surgery. Methods: Twenty-five patients with squamous cell carcinoma of the maxillary sinus treated by combined surgery and radiotherapy (50–65 Gy, median 60 Gy). Gross residual tumor volume (GRTV) after surgery was measured on computed tomograms obtained after surgery. Patients were classified according to GRTV as follows: group A, GRTV = 0 (microscopic residual, n = 5); group B, GRTV <10 cm3 (n = 11); group C, 10–40 cm3 (n = 5); and group D, =40 cm3 (n = 4). The relationship between local control and GRTV was analyzed using univariate and multivariate analysis. Results: The 2-year local control rate for all patients was 64%. The differences in local control rates between groups A, B and C were not significant (P > 0.05), but the rate was significantly lower in group D than in the other groups (65% at 2 years vs. 25% at 1 year, P < 0.001). Multivariate analysis showed that GRTV (P = 0.002) and histological differentiation (poorly differentiated histology was favorable, P = 0.035) were independent prognostic factors and that tumor stage and the sequence of treatment were not. Conclusions: Our data suggest that adequate, not complete, debulking associated with the proper dose of radiotherapy can provide satisfactory local control for patients with squamous cell carcinoma of the maxillary sinus. No significant financial relationships to disclose.
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Zeinali Torbati, Reza, Ian D. Turnbull, Rocky S. Taylor, and Derek Mueller. "Evaluation of the relative contribution of meteorological and oceanic forces to the drift of ice islands offshore Newfoundland." Journal of Glaciology 66, no. 256 (January 10, 2020): 203–18. http://dx.doi.org/10.1017/jog.2019.96.
Повний текст джерелаАнотація:
AbstractOn 29 April 2015, four beacons were deployed onto an ice island in the Strait of Belle Isle to record positional data. The ice island later broke up into many fragments, four of which were tracked by the beacons. The relative influences of wind drag, current drag, Coriolis force, sea surface height gradient and sea-ice force on the drift of the tracked ice island fragments were analyzed. Using atmospheric and oceanic model outputs, the sea-ice force was calculated as the residual of the fragments' net forces and the sum of all other forces. This was compared against the force obtained through ice concentration-dependent relationships when sea ice was present. The sea-ice forces calculated from the residual approach and concentration-dependent relationships were significant only when sea ice was present at medium-high concentrations in the vicinity of the ice island fragments. The forces from ocean currents and sea surface tilt contributed the most to the drift of the ice island fragments. Wind, however, played a minimal role in the total force governing the drift of the four ice island fragments, and Coriolis force was significant when the fragments were drifting at higher speeds.
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Vyzhva, S., V. Onyshchuk, I. Onyshchuk, M. Reva, and O. Shabatura. "RESERVOIR PROPERTIES OF CONSOLIDATED TERRIGENOUS ROCKS OF CAMBRIAN PERIOD OF THE EASTERN SLOPE OF THE LVIV PALEOZOIC DEPRESSION." Visnyk of Taras Shevchenko National University of Kyiv. Geology, no. 3(98) (2022): 33–41. http://dx.doi.org/10.17721/1728-2713.98.04.
Повний текст джерелаАнотація:
The paper concerned the researches of porosity and permeability properties of consolidated terrigenous reservoir rocks of Cambrian period of the Eastern slope of the Lviv depression. The purpose of the research was to study the petrophysical parameters of the consolidated reservoir rocks, as the basis of the integrated analysis of their physical properties. Such reservoir parameters as the open porosity factor and void factor, permeability coefficient and residual water saturation factor have been studied. The article presents the limits of changes and the average values of porosity and permeability properties of rocks, and the classification of their reservoir properties. On the basis of capillarimetric research, an evaluation of the structure of the void space of rocks was made. The correlation analysis has allowed to establish a series of empirical relationships between the reservoir parameters (density, porosity coefficient, effective porosity factor and residual water saturation factor) and, also, to determine correlation dependences between porosity coefficients measured in atmospheric and reservoir conditions. These relationships can be used in the data interpretation of geophysical studies of wells and in the modeling of porosity and permeability properties of consolidated rocks of the Eastern slope of the Lviv depression.
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H.M.P.P.S. Herath and D.M. Endagamage. "How the Supply Chain Management Practices influence on Operational Performance? A Case of Manufacturing Firms in Sri Lanka." Integrated Journal for Research in Arts and Humanities 2, no. 5 (September 1, 2022): 1–7. http://dx.doi.org/10.55544/ijrah.2.5.1.
Повний текст джерелаАнотація:
Most organisations in different sectors are implementing Supply Chain Management Practices (SCMPs) to create faster, more effective, and cost-beneficial relationships between business partners, to increase their Operational Performances. Even though the firms use SCMPs, their knowledge regarding the effectiveness of these practices is questionable. The aim of this study was to identify the most influential SCMPs on the Operational Performances of the Sri Lankan manufacturing industry. As to the literature and due to the high level of applicability in the manufacturing sector, five factors; Supply Relationship Management, Customer Relationship Management, Information Sharing, Logistics, and Outsourcing of Services were selected to conceptualize the current study. The Operational Performance of a Manufacturing organization has defined as the performance related to the quality, cost, delivery, and flexibility to change the volume. This was a cross-sectional questionnaire based survey which is quantitative in nature and primarily concerned with the testing of hypotheses. A set of 37 close-ended questions used to collect data from 200 randomly selected organizations. However, due to the difficulties faced in the pandemic environment, the success rate was 58.5%. Results of the Correlation Analysis confirmed the relationships hypothesized according to the theoretical behaviour with positive relationships significant at a 1% level. The strongest relationship shows between Logistics and Operational Performances (0.832). Regression Analysis showed significant impacts of Supplier Relationship Management (β=0.276) and Logistics (β=0.261) on the Operational Performance. Customer Relationship Management, Information Sharing, and outsourcing were not showed a significant impact on the Operational Performance at the 5% level. The adequacy of the fitted model is 67% and the RMSE is 0.236. The residual analysis also ensured the accuracy of the model with normally distributed residuals, free of Multi-collinearity, and having homoscedasticity which emphasises the constant variance of the residuals. The findings emphasise that if the SCMPs is running at a righteous level, an organization can keep their Operational Performances at a higher level. However, only the Supplier Relationship and Logistic activities are the factors significantly influencing the Operational Performances of the Manufacturing sector in Sri Lanka. Similar to the facts highlighted in the literature, the responses of the current study also showed a poor level of handling and utilizing customer feedback for the development of Sri Lankan organizations. Information sharing also showed a poor focus on integrating and enhancing the IT systems. The uncontrollable circumstances due to outsourcing the services lead to a poor level of operational performance at the finale. This research contributes to the existing Supply Chain Management literature by providing empirical evidence from the Sri Lankan manufacturing industry.
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Shi, Yifeng, Junier Oliva, and Marc Niethammer. "Deep Message Passing on Sets." Proceedings of the AAAI Conference on Artificial Intelligence 34, no. 04 (April 3, 2020): 5750–57. http://dx.doi.org/10.1609/aaai.v34i04.6031.
Повний текст джерелаАнотація:
Modern methods for learning over graph input data have shown the fruitfulness of accounting for relationships among elements in a collection. However, most methods that learn over set input data use only rudimentary approaches to exploit intra-collection relationships. In this work we introduce Deep Message Passing on Sets (DMPS), a novel method that incorporates relational learning for sets. DMPS not only connects learning on graphs with learning on sets via deep kernel learning, but it also bridges message passing on sets and traditional diffusion dynamics commonly used in denoising models. Based on these connections, we develop two new blocks for relational learning on sets: the set-denoising block and the set-residual block. The former is motivated by the connection between message passing on general graphs and diffusion-based denoising models, whereas the latter is inspired by the well-known residual network. In addition to demonstrating the interpretability of our model by learning the true underlying relational structure experimentally, we also show the effectiveness of our approach on both synthetic and real-world datasets by achieving results that are competitive with or outperform the state-of-the-art. For readers who are interested in the detailed derivations of serveral results that we present in this work, please see the supplementary material at: https://arxiv.org/abs/1909.09877.
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Solmon, Melinda A., and Amelia M. Lee. "Entry Characteristics, Practice Variables, and Cognition: Student Mediation of Instruction." Journal of Teaching in Physical Education 15, no. 2 (January 1996): 136–50. http://dx.doi.org/10.1123/jtpe.15.2.136.
Повний текст джерелаАнотація:
In this study, relationships between entry characteristics, in-class behavior, self-report measures of student cognition, and achievement during motor skill instruction were examined. Fifty-six sixth-grade students participated in a 4-day instructional unit on the forearm pass in volleyball. All classes were videotaped to code in-class behavior. Data collection included skill pretest and posttest, Harter’s Perceived Competence Scale, forms about the errors made during practice, and a Cognitive Processes Questionnaire (CPQ). Correlates of achievement, as reflected by residual gain scores, were perceived competence, student reports of attention, and variables indicating the quality of practice. Relationships between entry characteristics, in-class behavior, and measures of cognition were evaluated using canonical correlational analyses, and these relationships suggest that entry characteristics are important factors in how students interact in achievement settings. The results of this study show that investigating the complex relationships between these sets of variables can yield results that clarify how students effectively mediate instruction.
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Huang, Shongming. "Ecoregion-Based Individual Tree Height-Diameter Models for Lodgepole Pine in Alberta." Western Journal of Applied Forestry 14, no. 4 (October 1, 1999): 186–93. http://dx.doi.org/10.1093/wjaf/14.4.186.
Повний текст джерелаАнотація:
Abstract Using the felled tree data, ecoregion-based height-diameter models were developed for lodgepole pine (Pinus contorta var. latifolia) in Alberta. A large number of height-diameter functions were evaluated, and the Chapman-Richards function was found to produce some of the most satisfactory fits. Residual analysis was conducted to identify the error structure of the models. A weighting factor of wi = 1/Di was found appropriate for achieving the equal error variance assumption. Differences of the height-diameter models among different ecoregions were examined and tested using the nonlinear extra sum of squares method. Most height-diameter relationships were found to be different among different ecoregions. Ecoregions of similar height-diameter relationships were combined to provide a composite model to facilitate the practical use of such relationships. West. J. Appl. For. 14(4):186-193.
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Burbrink, Frank T., Felipe G. Grazziotin, R. Alexander Pyron, David Cundall, Steve Donnellan, Frances Irish, J. Scott Keogh, et al. "Interrogating Genomic-Scale Data for Squamata (Lizards, Snakes, and Amphisbaenians) Shows no Support for Key Traditional Morphological Relationships." Systematic Biology 69, no. 3 (September 24, 2019): 502–20. http://dx.doi.org/10.1093/sysbio/syz062.
Повний текст джерелаАнотація:
Abstract Genomics is narrowing uncertainty in the phylogenetic structure for many amniote groups. For one of the most diverse and species-rich groups, the squamate reptiles (lizards, snakes, and amphisbaenians), an inverse correlation between the number of taxa and loci sampled still persists across all publications using DNA sequence data and reaching a consensus on the relationships among them has been highly problematic. In this study, we use high-throughput sequence data from 289 samples covering 75 families of squamates to address phylogenetic affinities, estimate divergence times, and characterize residual topological uncertainty in the presence of genome-scale data. Importantly, we address genomic support for the traditional taxonomic groupings Scleroglossa and Macrostomata using novel machine-learning techniques. We interrogate genes using various metrics inherent to these loci, including parsimony-informative sites (PIS), phylogenetic informativeness, length, gaps, number of substitutions, and site concordance to understand why certain loci fail to find previously well-supported molecular clades and how they fail to support species-tree estimates. We show that both incomplete lineage sorting and poor gene-tree estimation (due to a few undesirable gene properties, such as an insufficient number of PIS), may account for most gene and species-tree discordance. We find overwhelming signal for Toxicofera, and also show that none of the loci included in this study supports Scleroglossa or Macrostomata. We comment on the origins and diversification of Squamata throughout the Mesozoic and underscore remaining uncertainties that persist in both deeper parts of the tree (e.g., relationships between Dibamia, Gekkota, and remaining squamates; among the three toxicoferan clades Iguania, Serpentes, and Anguiformes) and within specific clades (e.g., affinities among gekkotan, pleurodont iguanians, and colubroid families).
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Koulouris, Konstantinos, and Charis Apostolopoulos. "Study of the Residual Bond Strength between Corroded Steel Bars and Concrete—A Comparison with the Recommendations of Fib Model Code 2010." Metals 11, no. 5 (May 4, 2021): 757. http://dx.doi.org/10.3390/met11050757.
Повний текст джерелаАнотація:
As is well known, corrosion of steel reinforcement deteriorates the steel–concrete interface and causes concrete cracking, degrading significantly the bond strength. Several experimental studies have investigated the magnitude of residual bond strength due to corrosion, which affects either the function of corrosion-damaged steel bars or the surface crack width in concrete. As a result, linear and exponential correlation relationships have been proposed in order to predict the bond loss due to corrosion. Based on the results of an ongoing experimental campaign on the degradation of bond strength of RC specimens, combined with comparable outcomes from existing literature, this manuscript summarizes a database, comparing with the recommendations of Model Code 2010, to analyze and interpret the corrosion effect on the bond loss and highlights some points that need improvement in the current regulations. As indicated, the density of transverse reinforcement (stirrups spacing) has intense impact on the resulting bond loss due to corrosion. Hence, in order to quantify this aspect, the present manuscript introduces a discretization of confinement levels of RC elements, depending on the stirrups spacing. Based on this, regression analyses of data were conducted to extract fitting curves of bond loss, taking into account the amount of transverse reinforcement and predictive zones of residual bond strength in relationship to either corrosion penetration or surface crack width. Furthermore, the outcomes demonstrate that the corrosion penetration depth is an appropriate assessment tool to correlate the residual bond strength with the corrosion level, whereas the surface crack width on concrete is not yet an effective index, since there is a plethora of factors affecting the crack width. Due to this, more research is needed to improve the current level of knowledge on the surface crack width and link it with the corrosion damage of the steel bar and the residual bond strength due to corrosion.
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Bukowska, Mirosława. "Post-Critical Mechanical Properties Of Sedimentary Rocks In The Upper Silesian Coal Basin (Poland)." Archives of Mining Sciences 60, no. 2 (June 1, 2015): 517–34. http://dx.doi.org/10.1515/amsc-2015-0034.
Повний текст джерелаАнотація:
AbstractIn this paper, we present the results of a study of the Upper Carboniferous sedimentary rocks of the Upper Silesian Coal Basin (USCB) in Poland. We examined the hard coals, which belong to various stratigraphic units of Upper Carboniferous coal-bearing strata, and waste rocks, i.e., sandstones, mudstones, claystones. We present the results of tests of their post-critical mechanical properties. These results are from tests of the post-critical modulus, residual stress and residual deformation from experiments using a servo-controlled testing machine (MTS) with uniaxial compression and conventional triaxial compression. We applied confining pressures of up to 50 MPa at a strain rate of 10−5− 10−1s−1(0.003-6.0 mm/sec). The confining pressure applied in the triaxial compression tests reflected the conditions of current and future mining activities in the USCB at depths exceeding 1.300 metres. The strain rate applied in the tests reflected the values observed in the rockmass surrounding the mine workings and the rate of certain geodynamic phenomena occurring in the Carboniferous rockmass in the USCB, e.g., rock bursts. We present the values of the sub-critical modulus of coals and waste rocks, the functional relationships between the post-critical modulus and uniaxial compression strength, which are described using an exponential function of high correlation coefficients of the given rocks, and an exponential relationship between the post-critical modulus and the longitudinal elasticity modulus (Young’s modulus). Based on the results of tests of the post-critical properties of the Carboniferous rocks under triaxial compression and at various strain rates, we devised the functional relationships between the properties of the rocks and the confining pressure. The dependence of the post-critical modulus of the sandstones and claystones on the confining pressure is described using a polynomial function of degree 2, and that of the coals is described using an exponential function. The relationship between the residual stress and residual deformation in the rocks and the confining pressure was described using a linear function. The obtained results of tests have a practical application in forecasting behaviour of rocks located deep, and designing safe exploitation of mineral deposits. Confining pressures of up to 50 MPa used in the conventional triaxial compression tests allowed us to predict the behaviour of the rock mass at large depths. These data provide general knowledge of the tendencies in behaviour of rocks at substantial depths and the ability to design safe methods of mining deposits of various raw materials, including energy sources. These deposits are mined from increasingly great depths as the reserves are gradually exhausted and collieries of the largest European coal basins are continuously reconfigured.
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Lancaster, Phillip A., Mike Davis, Jack Rutledge, and Larry Cundiff. "72 Relationships Among Lifetime Feed Efficiency Traits in Growing Heifers, Mature Cows and Their Progeny." Journal of Animal Science 99, Supplement_1 (May 1, 2021): 118–19. http://dx.doi.org/10.1093/jas/skab054.196.
Повний текст джерелаАнотація:
Abstract Uncertainty exists in relationships among feed efficiency traits in different production stages. The objective of this study was to evaluate the relationships among feed efficiency traits measured in various stages of production. Data were collected from 1953 through 1980 from dams (n = 160), and their progeny (n = 406). Individual feed intake was measured from 240 d of age through weaning of 3rd calf for dams, and from weaning to slaughter for progeny. Body weight was measured at 28-d intervals until first parturition for heifers and slaughter for progeny, and cows were weighed at parturition and weaning each production cycle. Milk yield of dams was measured at 14-d intervals throughout lactation. Residual feed intake was computed as the residual from linear regression of daily DMI on metabolic mid-test body weight, average daily gain, and milk yield for dams only with year-diet-breed factor as a random effect using lmer function in R software. Pearson correlation coefficients were computed using corr.test function. Pearson correlations of RFI with DMI ranged from 0.58 to 0.74 and with feed:gain or feed:milk ranged from 0.24 to 0.67 within production stage. Heifer RFI was correlated with cow RFI during parity 1 (0.74), but not parity 2 (0.11) or 3 (-0.06). Heifer RFI was correlated with progeny 3 RFI (0.17), but not progeny 1 or 2 RFI. Cow RFI was weakly correlated among parities (0.25 to 0.36) whereas feed:milk was strongly correlated (0.56 to 0.70). Cow RFI was not correlated with progeny RFI of the same parity. In conclusion, RFI was poorly correlated across stage of production.
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Apiolaza, Luis A., Arthur R. Gilmour, and Dorian J. Garrick. "Variance modelling of longitudinal height data from a Pinus radiata progeny test." Canadian Journal of Forest Research 30, no. 4 (April 1, 2000): 645–54. http://dx.doi.org/10.1139/x99-246.
Повний текст джерелаАнотація:
Variance components were estimated using alternative structures for the additive genetic covariance matrix (G0), for height (m) of trees measured at 10 unequally spaced ages in an open-pollinated progeny test. These structures reflected unstructured, autoregressive, banded correlation and random regressions models. The residual matrix (R0) was unstructured, and the block and plot strata matrices were autoregressive. The best model for G0 considering the likelihood value and number of parameters was the autoregressive correlation form with age-specific variances and time on a natural logarithm basis. The genetic correlation between successive measures ranged from 0.93 at age 1 to 0.99 at age 14 years. Heritability increased with age from 0.09 (age 1) to 0.24 (age 7) and then declined to 0.13 at age 15. Heritabilities from the unstructured model were similar, while heritabilities assuming banded correlations were lower after age 7. The covariance structure implicit in the random regressions model was considered unsatisfactory. Using structures in G0 facilitated model fitting and convergence of the likelihood maximisation algorithm. Fitting a structured matrix that reflects the relationships present in repeated measures may overcome problems of nonpositive definiteness of unstructured matrices from longitudinal data, especially when genetic variation is small.