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Detecting trends in body size: empirical and statistical requirements for intraspecific analyses

Current Zoology 2019年第5期65卷 493-497页

作者： C.M.GIENGER ned a.dochtermann C.Richard TRACY Department of Biology Center of Excellence for Field BiologyAustin Peay State UniversityClarksvilleTNUSA Department of Biological Sciences North Dakota State UniversityFargoNDUSA Department of Biology Program in EcologyEvolutionand Conservation BiologyUniversity of NevadaRenoNVUSA

Attributing biological explanations to observed ecogeographical and ecological patterns require eliminating potential statistical and sampling artifacts as alternative explanations of the observed ***,we assess the role of sample size,statistical power,and geographic inclusivity on the general validity and statistical significance of relationships between body size and latitude for 3 well-studied species of *** extend those analyses to emphasize the importance of using statistically robust data in determining macroecological *** examined intraspecific trends in body size with latitude in Chelydra serpentina,Chrysemys picta,and Trachemys scripts using Pearson's correlations,diagnostic tests for influential points,and *** data were insufficient to ascertain a latitudinal trend in body size for *** or *** was a significant relationship for ***,however,resampling analyses show that,on average,16 of the 23 available independent populations were needed to demonstrate a significant relationship and that at least 20 of 23 populations were required to obtain a statistically powerful correlation between body size and ***,restricting the latitudes of populations resampled shows that body size trends of *** were largely due to leveraging effects of populations at the edge of the species *** results suggest that broad inferences regarding ecological trends in body size should be made with caution until underlying(intraspecific)patterns in body size can be statistically and conclusively demonstrated.

关键词： Bergmann's rule geographic variation macroecology resampling sensitivity analysis statistical power turtle

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Speciation along a shared evolutionary trajectory

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Current Zoology 2016年第6期62卷 507-511页

作者： ned A. dochtermann Marjorie D. MATOCQ Department of Biological Sciences North Dakota State University Fargo ND 58108-6050 USA Department of Natural Resources and Environmental Sciences Program in Ecology Evolution and Conservation Biology University of Nevada Reno USA

Groups of organisms-whether multiple species or populations of a single species-can differ in several non-exclusive ways. For example, groups may have diverged phenotypically, genetically, or in the evolutionary responses available to them. We tested for the latter of these-response di- vergence-between 2 species of woodrats： Neotoma fuscipes and Neotoma macrotis. Based on random skewers analyses we found that, despite being well differentiated both phenotypically and genetically, N. fuscipes and N. macrotis appear to be diverging along a shared evolutionary trajec- tory （ro = 0.895, P= 0.114）. Because these species are currently in secondary contact, their phenotypic evolution being along a shared evolutionary axis has important implications. In particular, that their response to selection arising from interspecific interactions will be constrained along the same evolutionary trajectory may reduce the potential for reinforcing selection to maintain species boundaries.

关键词： Divergence Neotoma random skewers speciation.

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Individual variability in life-history traits drives population size stability

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Current Zoology 2012年第2期58卷 358-362页

作者： ned A. dochtermann C. M. GIENGER Department of Biology Umverslty of Nevada Reno NV 89557 USA Department of Biology and Center of Excellence for Field Biology Austin Peay State University Clarksville TN 37044 USA

Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our under- standing of population dynamics has historically been based on an assumption that individuals are identical with homogenous life-history properties. This assumption is certainly false for most natural systems, raising the question of what role individual variation plays in the dynamics of populations. While there has been an increase of interest regarding the effects of within popula- tion variation on the dynamics of single populations, there has been little study of the effects of differences in within population variation on patterns observed across populations. We found that life-history differences （clutch size） among individuals ex- plained the majority of the variation observed in the degree to which population sizes of eastern fence lizards Sceloporus undula- tus fluctuated. This finding suggests that differences across populations cannot be understood without an examination of differences at the level of a system rather than at the level of the individual

关键词： Individual variation Population size variability Ecological stability Demographic stochasticity Demographic heterogeneity Sceloporus undulatus

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Materials for energy conversion

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Science Bulletin 2016年第8期61卷 585-586页

作者： ned Djilali Institute for Integrated Energy Systems University of Victoria Renewable Energy Research Group King Abdulaziz University

Advances in material science and engineering are critical to the development of economically viable technologies to address some of the grand socio-economic challenges of the twenty first *** are at the core

关键词：能量转换材料可再生能源资源太阳能电池存储技术社会经济能源转换材料科学能源需求

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Anti-Tumor Immunology in BMT:Separating Graft versus Leukemia from Graft versus Host Disease

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中国实用内科杂志 2007年第S1期27卷 1-8页

作者： ned Waller Bone Marrow and Stem Cell Transplant Center Emory University

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Role of simple biomarkers in predicting fibrosis progression in HCV infection

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World Journal of Gastroenterology 2010年第45期16卷 5710-5715页

作者： Rajasekhara R Mummadi John R Petersen ned Snyder Division of Gastroenterology and Hepatology Department of Internal MedicineUniversity of Texas Medical BranchHoustonTX 77025United States Department of Pathology University of Texas Medical BranchHoustonTX 77025United States Department of Gastroenterology and Hepatology Kelsey Seybold Clinic2727 W. HolcombeHoustonTX 77025United States

AIM: To examine the accuracy of the aspartate aminotransferase (AST)/Platelet Ratio Index (APRI) and FIB-4, in predicting longitudinal changes in liver histology in hepatitis C virus (HCV) ***: Patients that underwent repeat liver biopsies at least 1 year apart from 1999 to 2007 were identified. Liver fibrosis was staged on needle core biopsies evaluated by a single expert liver pathologist. Only laboratory values within 3 mo of the liver biopsies were ***: Thirty-six patients met the inclusion criteria with 50% stage 1 on initial biopsy, 25% stage 2, and 22% stage 3. Nineteen of 36 (53%) had progression of fibrosis on repeat biopsies, while 16 (44%) showed no change in stage, and one (3%) showed improvement. Patients that showed progression of fibrosis had significantly higher alanine aminotransferase and aspartate aminotransferase levels than the group that did not show progression. A significant correlation was seen between change in stage of fibrosis and change in APRI (r2 = 0.39, P = 0.00001) and a change in FIB-4 (r2 = 0.31, P = 0.00004). A change in APRI (ΔAPRI) of 0.18 had 80% positive predictive value (PPV) and 67% nega- tive predictive value (NPV) for progression of fibrosis. A change in FIB-4 (ΔFIB-4) of 0.39 had 75% PPV and 75% NPV for predicting progression of fibrosis. CONCLUSION: ΔAPRI and ΔFIB-4 parallel changes in fibrosis progression, and could be useful tools for clinicians in following patients with active chronic HCV infection.

关键词： Hepatitis C Liver fibrosis Liver biopsy Biomarkers

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Chronic hepatitis C is a common associated with hepatic granulomas

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World Journal of Gastroenterology 2008年第41期14卷 6366-6369页

作者： ned Snyder Juan G Martinez Shu-Yuan Xiao Department of Internal Medicine University of Texas Medical Branch Galveston Texas 77555-0764 United States Department of Pathology University of Texas Medical Branch Galveston Texas 77555-0588 United States

AIM： To determine the most frequent etiologies of hepatic epithelioid granulomas, and whether there was an association with chronic hepatitis C virus （HCV）. METHODS： Both a retrospective review of the pathol- ogy database of liver biopsies at our institution from 1996 through 2006 as well as data from a prospective study of hepatic fibrosis markers and liver biopsies from 2003 to 2006 were reviewed to identify cases of hepatic epithelioid granulomas. Appropriate charts, liver biopsy slides, and laboratory data were reviewed to determine all possible associations. The diagnosis of HCV was based on a positive HCV RNA. RESULTS： There were 4578 liver biopsies and 36 （0.79%） had at least one epithelioid granuloma. HCV was the most common association. Fourteen patients had HCV, and in nine, there were no concurrent condi- tions known to be associated with hepatic granulomas. Prior interferon therapy and crystalloid substances from illicit intravenous injections did not account for the finding. There were hepatic epithelioid granulomas in 3 of 241 patients （1.24%） with known chronic HCV enrolled in the prospective study of hepatic fibrosis markers. CONCLUSION： Although uncommon, hepatic granu- Iomas may be part of the histological spectrum of chronic HCV. When epithelioid granulomas are found on the liver biopsy of someone with HCV, other clini- cally appropriate studies should be done, but if nothing else is found, the clinician can be comfortable with an HCV association.

关键词： Hepatitis C Liver Granulomas Liver biopsy

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Using an ILU/Deflation Preconditioner for Simulation of a PEMFuel Cell Cathode Catalyst Layer

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Communications in Computational Physics 2013年第8期14卷 537-573页

作者： Kyle J.Lange Pang-Chieh Sui ned Djilali Institute of Integrated Energy Systems University of VictoriaBCCanada Department of Mechanical Engineering University of VictoriaBCCanada Currently at Lawrence Livermore National Laboratory LivermoreCAUSA

Numerical aspects of a pore scale model are investigated for the simulation of catalyst layers of polymer electrolyte membrane fuel *** heat,mass and charged species transport together with reaction kinetics are taken into account using parallelized finite volume simulations for a range of nanostructured,computationally reconstructed catalyst layer *** effectiveness of implementing deflation as a second stage preconditioner generally improves convergence and results in better convergence behavior than more sophisticated first stage *** behavior is attributed to the fact that the two stage preconditioner updates the preconditioning matrix at every GMRES restart,reducing the stalling effects that are commonly observed in restarted GMRES when a single stage preconditioner is *** addition,the effectiveness of the deflation preconditioner is independent of the number of processors,whereas the localized block ILU preconditioner deteriorates in quality as the number of processors is *** total number of GMRES search directions required for convergence varies considerably depending on the preconditioner,but also depends on the catalyst layer microstructure,with low porosity microstructures requiring a smaller number of *** improved model and numerical solution strategy should allow simulations for larger computational domains and improve the reliability of the predicted transport *** preconditioning strategies presented in the paper are scalable and should prove effective for massively parallel simulations of other problems involving nonlinear equations.

关键词： Deflation PEM fuel cell catalyst layer pore scale model porous media preconditioner

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Experimental and numerical investigation of a solar eductorassisted low-pressure water desalination system

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Science Bulletin 2016年第12期61卷 959-973页

作者： Mehran Ahmadi Poovanna Thimmaiah Majid Bahrami Khaled Sedraoui Hani H.Sait ned Djilali Laboratory for Alternative Energy Conversion (LAEC) School of Mechatronic Systems Engineering Simon Fraser University Renewable Energy Research Group King Abdulaziz University Department of Mechanical Engineering and Institute for Integrated Energy Systems University of Victoria

Greenhouse solar-energy driven desalination technology is potentially well suited for supplying water and small scale irrigation in remote and/or rural areas, and for avoiding over-exploitation of available water resources. The efficiency and productivity of these systems are however low, in part because the heat of evaporation has to be transferred as waste heat to ambient air during condensation. In order to maximize energy regeneration during condensation we propose an educator based system that lowers the evaporation process temperature by reducing pressure. The feasibility of the educator assisted passive solar desalination system is investigated using a detailed computational fluid dynamics analysis complemented by experiments. The study focuses in particular on the ability of the new design to lower the required evaporation temperature and thereby reduce the energy intensity of the process. Two configurations, with open and closed educator, are investigated and a detailed analysis of the thermofluid processes is presented. The configuration with a closed educator installed outside the evaporation chamber shows very promising performance. The proposed system can maintain the maximum temperature and pressure in theevaporation chamber below the desirable temperature and pressure thresholds （30 ℃ and 5 kPa）. The analysis and experimental data also show it is possible to further reduce energy requirements by reducing the motive water flow rates.

关键词： Desalination. Solar energy EvaporationHumidification Dehumidification Regenerative heating

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Active power regulation of wind power systems through demand response

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Science China(Technological Sciences) 2012年第6期55卷 1667-1676页

作者： MIAO WeiWei JIA HongJie WANG Dan PARKINSON Simon CRAWFORD Curran DJILALI ned Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjin 300072China Institute for Integrated Energy Systems University of VictoriaVictoria BC V8W3P6Canada

With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the *** to the variable and intermittent nature of wind power production,the system has to frequently redispatch generators in order to ensure the effective use of wind power whilst maintaining system *** this way,traditional generation costs are increased and the social benefit of wind power decreases *** this paper,a new regulation strategy based on power flow tracing was proposed,taking advantage of a comfort-constrained demand response strategy to follow the fluctuations of wind farm output,with the remaining imbalance of active power compensated by traditional *** showed that compared with conventional regulation,demand response could reduce the gross operating costs of the system,and the rapid response could help maintaining system stability in case of *** strategy in this paper also applies to other large-scale integration problems associated with renewable energy resources which display short-term production variability.

关键词： wind power active power regulation power flow tracing demand response heat pump

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