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Earthworm contributions to soil nitrogen supply in corn-soybean agroecosystems in Quebec, Canada

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Pedosphere 2021年第3期31卷 405-412页

作者： Zhor ABAIL joann KWHALEN National Institute of Agricultural Research(INRA) Kenitra B.P.257Morocco Department of Natural Resource Sciences Macdonald Campus of McGill UniversitySte-Anne-de-BellevueQuebec H9X 3V9Canada

Accurately quantifying the soil nitrogen(N)supply in crop fields is essential for enabling environmentally sustainable and economically profitable crop *** requires using field-based methods to account for the contribution of soil biota,including earthworms,to N mineralization in temperate *** direct contribution of earthworms to the soil N cycle is the N they release throughout their life and after death,and it can be estimated using the secondary production *** study was conducted in 2014 and 2015 in two adjacent fields with annual corn-soybean rotation in Ste-Anne-de-Bellevue,Quebec,*** cumulative biomass of Aporrectodea *** two no-till corn-soybean agroecosystems was determined,and the direct N flux from these earthworms was estimated during the corn and soybean phases of the *** production was estimated by sampling earthworms biweekly during April-June and September-November and inferring the change in earthworm biomass between sampling dates using a size frequency *** N flux was calculated as the sum of the N released through excretion,during periods when earthworms were active,and from *** secondary production of the Aporrectodea population was estimated to be 8-43 g ash-free dry weight m^(-2) year^(-1),and the N flux was 22-105 kg N ha^(-1 )year^(-1).The N flux was higher at the early vegetative growth stage,which is a period of high N demand for *** findings suggest that refining the N fertilization recommendation by accounting for soil N supplied by earthworms could potentially reduce fertilizer costs and environmental N losses.

关键词： nitrogen excretionnitrogen fluxnitrogen releasesecondary productionsize frequency method

A new perspective on functional redundancy and phylogenetic niche conservatism in soil microbial communities

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Pedosphere 2020年第1期30卷 18-24页

作者： Yu JIA joann K.WHALEN Department of Natural Resource Sciences Macdonald Campus of McGill UniversitySte-Anne-de-BellevueQuebec H9X 3V9(Canada)

Functional redundancy in soil microbial communities seems to contradict the notion that individual species have distinct metabolic niches in multi-species *** soil microbiota have the metabolic capacity for"basic"functions(e.g.,respiration and nitrogen and phosphorus cycling),but only a few soil microbiota participate in"rare"functions(e.g.,methanogenesis and mineralization of recalcitrant organic pollutants).The objective of this perspective paper is to use the phylogenetic niche conservatism theory as an explanation for the functional redundancy of soil *** niche conservatism is defined as the tendency for lineages to retain ancestral functional characteristics through evolutionary *** present-day soil microbiota is the result of a community assembly process that started when prokaryotes first appeared on *** billions of years,microbiota have retained a highly conserved set of core genes that control the essential redox and biogeochemical reactions for life on *** genes are passed from microbe to microbe,which contributes to functional redundancy in soil microbiota at the planetary *** assembly of microbial communities during soil formation is consistent with phylogenetic niche *** a specific soil,the heterogeneous matrix provides an infinite number of sets of diverse environmental conditions,i.e.,niches that lead to the divergence of microbial *** phylogenetic niche conservatism theory predicts that two or more microbial species diverging from the same clade will have an overlap in their niches,implying that they are functionally redundant in some of their metabolic *** endogenous genetic factors that constrain the adaptation of individuals and,thus,populations to changing environmental conditions constitute the core process of phylogenetic niche ***,the degree of functional redundancy in a particular soil is proportional to the complexity of the

关键词： basic function conceptual model core gene environmental factor genetic factor niche overlap rare function soil biodiversity

Cognitive Style and Learning Strategies joann Salvisberg looks at current SLA theories and their possible applications to the classroom situation

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基础教育外语教学研究 2005年第3期 -页

作者： joann Salvisberg

People learn and process new information in different *** decades researchers have been studying and com- paring the personality traits any cognitive learning styles of students to discover any distinguishing trait patterns(*** characteristic of academically successful students than other learners).Moreover,many believe that if the classroom envi- ronment and even the teachers'teaching style can be tailored to meet the students'learning styles,learning as well as the students'self-concept as a ...

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Harmful algal blooms and eutrophication: "strategies" for nutrient uptake and growth outside the Redfield comfort zone

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Chinese Journal of Oceanology and Limnology 2011年第4期29卷 724-738页

作者： Patricia M. GLIBERT joann M. BURKHOLDER University of Maryland Center for Environmental Science Horn Point Laboratory PO Box 775 Cambridge MD 21613 USA Center for Applied Aquatic Ecology North Carolina State University Raleigh NC 27606 USA

While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.

关键词： HABs mixotrophy nitrogen nutrient loading nutrient ratios nutrient stoichiometry organicnutrients phosphorus

Earthworm populations are stable in temperate agricultural soils receiving wood-based biochar

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Pedosphere 2021年第3期31卷 398-404页

作者： joann KWHALEN Hicham BENSLIM Abdirashid AELMI Barry RHUSK Department of Natural Resource Sciences Macdonald Campus of McGill UniversitySte-Anne-de-BellevueQuebec H9X 3V9Canada Department of Environmental Technology Management College of Life SciencesKuwait UniversityP.O.Box 5969Safat 13060Kuwait BlueLeaf Inc. DrummondvilleQuebec J2B 5E9Canada

The application of decomposable organic residues such as manure and crop litter is generally beneficial to *** is an emerging interest in applying biochar,a carbonaceous product of pyrolysis,to temperate agricultural *** slow decomposition rate of biochar,which also contains ash and combustion byproducts,could be detrimental to *** objective of this study was to describe the earthworm populations in biochar-amended soils on a dairy farm in the *** River watershed,Quebec,*** were collected from replicated field plots under cereal *** A received three wood-based biochar types at two application rates(5 and 10 t ha^(-1) biochar)plus an unamended control,while Site B received wood-based biochar(7.5 t ha^(-1) biochar),dairy cattle slurry(10 t ha^(-1) manure),or a combination of the biochar and manure rates plus an unamended *** were collected by hand sorting and formaldehyde expulsion from soil *** species,Aporrectodea turgida,Aporrectodea tuberculata,and Lumbricus rubellus,were found at the sites,and Aporrectodea was the dominant *** sources,rates,and application with dairy slurry did not affect the earthworm population,which had 52-218 individuals m^(-2) in 2010 and 4-96 individuals m^(-2) in *** seasonal variation in earthworm population may be due to flooding in the spring of 2011,which apparently interfered with earthworm *** similarity in earthworm abundance and biomass in plots with and without wood-based biochar leads to the conclusion that earthworm populations are stable in biochar-amended soils in this cold,humid temperate region.

关键词： biochar-amended soilcornendogeic earthwormflooded soilpyrolysiswoody feedstock

Earthworm functional groups are related to denitrifier activity in riparian soils

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Pedosphere 2021年第3期31卷 413-422页

作者： Chen CHEN Leanne EJACK Martin RCHÉNIER joann KWHALEN State Environmental Protection Key Laboratory of Urban Ecological Environment Simulation and Protection South China Institute of Environmental SciencesMinistry of Ecology and Environment of ChinaGuangzhou 510535China Department of Natural Resource Sciences Macdonald CampusMcGill University21111 Lakeshore RoadSte-Anne-de-BellevueQuebec H9X 3V9Canada Department of Food Science and Agricultural Chemistry and Department of Animal Science Macdonald CampusMcGill University21111 Lakeshore RoadSte-Anne-de-BellevueQuebec H9X 3V9Canada

Riparian buffers,located in the transition zone between terrestrial and aquatic ecosystems,are a hotspot for nitrogen(N)removal through *** are abundant in riparian buffers and may enhance *** study investigated earthworm demographics of three earthworm functional groups(anecic,epigeic,and endogeic)and denitrifier activity in temporarily flooded and non-flooded riparian soils from April to October 2012 in southern Quebec,*** earthworm species,mostly endogeic,were found in the temporarily flooded soil,while only six earthworm species were found in the non-flooded *** average,there were 11.7 times more earthworms with 12.4 times greater biomass(P<0.05)found in the temporarily flooded soil than in the non-flooded *** denitrification enzyme activity(DEA)was of similar magnitude in temporarily flooded and non-flooded soils,with temporal variation associated with rainfall *** earthworm biomass was positively correlated(P<0.05)with DEA,while epigeic earthworm biomass was positively correlated(P<0.05)with 16S rRNA gene copies and nosZ gene copies from bacteria,indicating an association between earthworm functional groups and denitrifier activity in riparian *** multiple regressions showed that DEA in riparian soils could be predicted using soil moisture,inorganic N concentration,and earthworm functional groups,suggesting that endogeic and epigeic earthworms contributed to denitrifier activity in riparian soils.

关键词： endogeic earthwormsepigeic earthwormsriparian areasriparian buffermacrofaunaseasonal changedenitrification enzyme activitydenitrifier gene copy

Cardiac evaluation of liver transplant candidates

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World Journal of Gastroenterology 2008年第22期14卷 3445-3451页

作者： Mercedes Susan Mandell joann Lindenfeld Mei-Yung Tsou Michael Zimmerman Department of Anesthesiology University of Colorado Health Sciences Center Aurora Colorado 80045 United States Department of Cardiology University of Colorado Health Sciences Center Aurora Colorado 80045 United States Department of Anesthesiology Taipei Veterans General Hospital and National Yang-Ming University School of MedicineTaipei Taiwan Department of Surgery University of Colorado Health Sciences Center Aurora Colorado 80045 United States

Physicians previously thought that heart disease was rare in patients with end stage liver disease. However, recent evidence shows that the prevalence of ischemic heart disease and cardiomyopathy is increased in transplant candidates compared to most other surgical candidates. Investigators estimate that up to 26% of all liver transplant candidates have at least one critical coronary artery stenosis and that at least half of these patients will die perioperatively of cardiac complications. Cardiomyopathy also occurs in greater frequency. While all patients with advanced cardiac disease have defects in cardiac performance, a larger than expected number of patients have classical findings of dilated, restrictive and hypertropic cardiomyopathy. This may explain why up to 56% of patients suffer from hypoxemia due to pulmonary edema following transplant surgery. There is considerable controversy on how to screen transplant candidates for the presence of heart disease. Questions focus upon, which patients should be screened and what tests should be used. This review examines screening strategies for transplant candidates and details the prognostic value of common tests used to identify ischemic heart disease. We also review the physiological consequences of cardiomyopathy in transplant candidates and explore the specific syndrome of "cirrhotic cardiomyopathy".

关键词： Coronary artery disease Coronary atherosclerosis Echocardiography Cirrhosis Cardiomyo pathy Cardiac electrophysiology liver transplantation