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Competition for food in 2 populations of a wild-caught fish

Current Zoology 2018年第5期64卷 615-622页

作者： Pierre J.C. CHUARD grant E. BROWN James W.A. grant Research School of Biology The Australian National University Canberra ACT 0200 Australia Departmentof Biology Concordia University 7141 Sherbrooke Street West Montreal Quebec Canada H4B 1R6

Aggressive behavior when competing for resources is expected to increase as the ratio of competitors-to-resource ratio （CRR） units increases. Females are expected to be more aggressive than males when competing for food when body size is more strongly related to reproductive suc- cess in females than in males, whereas aggression is predicted to decrease under high ambient predation risk by natural selection. Under the risk allocation model, however, individuals under high ambient predation risk are expected to be more aggressive, and forage more in the absence of imminent risk than their low risk counterparts. An interaction between adult sex ratio （i.e., adult males/females）, ambient predation risk （high vs. low）, and sex on intrasexual competition for mates in Trinidadian guppies Poecilia reticulata has been shown. The interaction suggested an increase in aggression rates as CRR increased, except for males from the high predation population. To compare the patterns of competition for food versus mates, we replicated this study by using food patches. We allowed 4 male or 4 female guppies from high and low predation populations to com- pete for 5, 3, or 1 food patches. The foraging rate was higher in a high rather than low ambient pre- dation risk population. Surprisingly, CRR, sex, and population of origin had no effect on aggression rates. Despite other environmental differences between the 2 populations, the effect of ambient predation risk may be a likely explanation for differences in foraging rates. These results highlight the importance for individuals to secure food despite the cost of competition and predation.

关键词： aggression competitor-to-resource ratio foraging Poecifia reticulata population differences predation risk sex

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Effects of Mn content on recrystallization resistance of AA6082 aluminum alloys during post-deformation annealing

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Journal of Materials Science & Technology 2020年第17期52卷 189-197页

作者： Xiaoming Qian Nick Parson X.-grant Chen Department of Applied Science University of Quebec at ChicoutimiSaguenay G7H 2B1Canada Arvida Research and Development Centre Rio Tinto AluminumSaguenay G7S 4K8Canada

The microstructural evolutions under as-homogenized and as-deformed conditions and after the postdeformation annealing of AA6082 aluminum alloys with different Mn content(0.05 wt.%-1 wt.%)were studied by optical,scanning electron,and transmission electron *** results showed that the presence of a large amount ofα-Al(Mn,Fe)Si dispersoids induced by Mn addition significantly improved the recrystallization *** the base alloy free of Mn,static recrystallization occurred after 2 h of annealing,and grain growth commenced after 4 h of annealing,whereas in Mn-containing alloys,the recovered grain structure was well-retained after even 8 h of *** alloy with 0.5%Mn exhibited the best recrystallization resistance,and a further increase of the Mn levels to 1%resulted in a gradual reduction of the recrystallization resistance,the reason for which was that recrystallization occurred only in the dispersoid-free zones(DFZs)and the increased DFZ fraction with Mn content led to an increase in the recrystallization *** variation in the dispersoid number density and a coarsening of dispersoids during annealing have a limited influence on the static recrystallization in Mn-containing alloys.

关键词： AA6082 alloys Mn effects Recrystallization resistance Dispersoid precipitation Post-deformation annealing

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Improvement of elevated-temperature strength and recrystallization resistance via Mn-containing dispersoid strengthening in Al-Mg-Si 6082 alloys

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Journal of Materials Science & Technology 2020年第4期39卷 135-143页

作者： Chen Li Kun Liu X.-grant Chen Department of Applied Science University of Québec at ChicoutimiChicoutimiQC G7H 2B1Canada

The precipitation behavior of Mn-containing dispersoids in Al-Mg-Si 6082 alloys with different Mn contents(0,0.5 and 1.0 wt%)during various heat treatments(300–500℃)was *** effects of dispersoids on elevated-temperature strength and recrystallization resistance during hot-rolling and post-rolling annealing were *** results showed that the dispersoids in the Mn-containing alloys(0.5 and 1.0%)began to precipitate at 350℃and reached the optimum conditions after 2–4 h at 400℃.However,the dispersoids coarsened with increasing holding time at temperatures above450℃.After the peak precipitation treatment at 400℃for 2 h,the yield strength at 300℃increased from 28 MPa(base alloy free of Mn)to 55 MPa(alloy with 0.5%Mn)and 70 MPa(alloy with 1%Mn),respectively,demonstrating a significant dispersoid strengthening effect at elevated *** addition,the dispersoids were thermally stable at 300℃for up to 1000 h holding owing to its relative high precipitation temperature(350–400℃),leading to the superior constant mechanical performance at elevated temperature during the long service *** hot rolling and post-rolling annealing,the presence of a large amount of dispersoids results in the higher Zener drag PZcompared with base alloy and then significantly improved the recrystallization *** alloy containing 0.5%Mn exhibited the highest recrystallization resistance among three experimental alloys studied during the post-rolling process,likely resulted from the lower coarsening rate of dispersoids and the lower dispersoids free zone.

关键词： Al-Mg-Si 6082 alloy Mn addition Dispersoid precipitation Elevated-temperature strength Recrystallization resistance

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Detection and monitoring prostate specific antigen using nanotechnology approaches to biosensing

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Frontiers of Chemical Science and Engineering 2020年第1期14卷 4-18页

作者： grant Perry Fernando Cortezon-Tamarit Sofia I.Pascu Department of Chemistry University of BathClaverton DownBath BA27AYUK

Prostate cancer has a high incidence in men and remains the second cause of mortality due to cancer *** the development of the disease is greatly correlated to age,the identification of novel detection methods reliable,efficient,and cost effective is a matter of significant importance in the ageing population of western *** detection of the prostate specific antigen(PSA)in blood samples has been the preferred method for the detection and monitoring of prostate cancer over the past *** the indications against its use in massive population screening,PSA still remains the best studied biomarker for prostate cancer and the detection of its different forms and incorporation in multiplexed designs with other biomarkers still remains a highly valuable indicator in the theranostics of prostate *** latest developments in the use of nanomaterials towards the construction of PSA biosensors are reviewed *** incorporation of gold nanoparticles,silica nanoparticles and graphene nanostructures to biosensing devices has represented a big leap forward in terms of sensitivity,stability and *** electrochemical and optical detection methods for the detection of PSA will be reviewed herein.

关键词： biosensing immunosensor PSA prostate cancer fluorescence

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Recruitment and functionality traits as bioindicators of ecological restoration success in the Lurg Hills district,Victoria,Australia

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Ecological Processes 2013年第1期2卷 286-296页

作者： Kristin Monie Singarayer Florentine grant Palmer Centre for Environmental Management School of ScienceInformation Technology and EngineeringUniversity of BallaratPO Box 663BallaratVictoriaAustralia

Introduction:The Regent Honeyeater Project commenced ecological restoration in the Lurg district in 1994,with an aim to restore habitats for the critically endangered Regent Honeyeater Anthochaera phrygia and a range of other threatened and declining *** this context,our study aimed to explore whether plant reproduction can be an effective measure of ecological restoration ***:Evaluation involved comparing attributes at unrestored,restored and remnant sites to establish whether sites displayed evidence of a clear restoration *** age classes(unrestored,4–6 years old,8–10 years old,12–14 years old and remnant areas)and two landforms(upper hills and lower hills)were *** diversity of woody plant species—which have easily recognisable reproductive material and which all recruit seedlings—provides easily measured parameters that have the potential to allow the determination of early establishment success and long-term ecological development of restored ***:Restoration plantings developed in a hybrid state towards a benchmark in the lower hills;seedling species composition differed significantly among age classes,increasing in similarity with time since restoration,with some divergence from the target *** of functional groups with reproductive outputs was also significantly different among age classes;however,a restoration trajectory was only evident in the upper hills where sites converged towards the target ***:Divergence or deviation from the restoration trajectory was not deemed to be a restoration failure,as the variety of functional groups with fruits and diversity of seedlings recruiting indicated a potential increase in resilience in the future due to greater variability across the *** recruitment was effective in detecting development trends towards a restoration target in this study and therefore may be a useful measure that contributes to determining ecological

关键词： Restoration Assessment Ecological development Trajectory Monitoring

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Olfaction and reaction: The role of olfactory and hypothalamic investment in the antipredator responses to chemical alarm cues by northern redbelly dace

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Current Zoology 2023年第6期69卷 738-746页

作者： Brendan J.Joyce grant E.Brown Department of Biology Concordia UniversityMontrealQuebecCanada

Neuroplasticity enables teleosts to promote or downregulate the growth of their brains *** compensate for the effects of predation pressure,teleosts may alter their brain morphology and behavioral responses to mitigate its impact on individual ***-predation environ-ments often promote specific patterns of brain growth and produce bolder and more proactive *** to the expense of maintaining neural tissue,relative size indicates the regions most relied *** northern redbelly dace Chrosomus eos,as little as 2 weeks of elevated predation pressure,resulted in increased investment in their olfactory bulbs and optic tecta,while the imposition of captivity produced smaller,less symmetric *** together,these results suggest that an individual could potentially become better able to detect a threat,and simultaneously less inclined to react to it,making the impact of either change in isolation is difficult to ***,we compared interindividual variation in gross brain morphology,risk-taking tactics in a novel arena(shy-bold personality),and responding to olfactory cues(proactive/reac-tive stress-coping style).We hypothesized that olfactory investment would positively correlate with response intensity to predator cue concen-tration and respond across a wider range of cue concentrations,while hypothalamus size would correlate with shyness and *** to heightened risk produced more bold/proactive individuals,with larger olfactory bulbs and smaller ***,the direction of the correlation between hypothalamus size and behavior varied by treatment,and olfactory investment only corresponded with response intensity amongst proactive *** findings illustrate the potential pitfalls of relating gross brain morphology to complex behavior and suggest that stress-coping style is a relevant consideration in future studies.

关键词： boldness brainmorphology neuroplasticity predation proactivity stress-coping style

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Elevated CO_2 Accelerates Phosphorus Depletion by Common Bean(Phaseolus vulgaris) in Association with Altered Leaf Biochemical Properties

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Pedosphere 2018年第3期28卷 422-429页

作者： Zhong MA Jennifer FLYNN grant LIBRA Zechuan SHI Department of Biology Truman State University

Phosphorus （P） is a major limiting factor for plant productivity in many ecosystems and agriculture. The projected increase in atmospheric CO2 is likely to result in changes in plant mineral consumption and growth. We studied P depletion by common bean （Phaseolus vulgaris） cultured hydroponically under ambient （377±77μmol mol^-1） or elevated （650±32 μmol mol^-1） CO2 in media of low or high P. Under elevated CO2 compared to ambient CO2, the maximum P depletion rate increased by 98% at low P and 250% at high P, and P was depleted about 2-5 weeks sooner; leaf acid phosphatase （APase） activity and chlorophyll content both increased significantly; root-to-shoot ratio increased significantly at high P, although it was unaffected at low P; lateral root respiration rate showed no change, suggesting that COs did not affect P depletion via metabolic changes to the roots; the total biomass at final harvest was significantly higher at both low and high P. Our data showed that the increased rate and amount of P depletion during plant growth under elevated CO2 occurred in association with alterations in leaf biochemical properties, i.e., enhanced activities of leaf APase and increased leaf chlorophyll content.

关键词： acid phosphatase biomass partitioning chlorophyll climate change dry matter accumulation mineral nutrition

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Multipotent pancreas progenitors: Inconclusive but pivotal topic

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World Journal of Stem Cells 2015年第11期7卷 1251-1261页

作者： Fang-Xu Jiang grant Morahan Islet Cell Development Program Harry Perkins Institute of Medical Research Centre for Medical Research the University of Western Australia Centre for Diabetes Research Harry Perkins Institute of Medical Research

The establishment of multipotent pancreas progenitors(MPP) should have a significant impact not only on the ontology of the pancreas, but also for the translational research of glucose-responding endocrine b-cells. Deficiency of the latter may lead to the pandemic type 1 or type 2 diabetes mellitus, a metabolic disorder. An ideal treatment of which would potentially be the replacement of destroyed or failed b-cells, by restoring function of endogenous pancreatic endocrine cells or by transplantation of donor islets or in vitro generated insulin-secreting cells. Thus, considerable research efforts have been devoted to identify MPP candidates in the preand post-natal pancreas for the endogenous neogenesis or regeneration of endocrine insulin-secreting cells. In order to advance this inconclusive but critical field, we here review the emerging concepts, recent literature and newest developments of potential MPP and propose measures that would assist its forward progression.

关键词： Multipotent pancreas progenitors Regeneration Self-renewal Clonogenesis Differentiation

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Stability Analysis and Performance Evaluation of Additive Mixed-Precision Runge-Kutta Methods

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Communications on Applied Mathematics and Computation 2024年第1期6卷 705-738页

作者： Ben Burnett Sigal Gottlieb Zachary J.grant Center for Scientific Computing and Data Science Research UMass DartmouthNorth DartmouthMassachusettsUSA CSME Michigan State UniversityEast LansingMichiganUSA

Additive Runge-Kutta methods designed for preserving highly accurate solutions in mixed-precision computation were previously proposed and *** specially designed methods use reduced precision for the implicit computations and full precision for the explicit *** this work,we analyze the stability properties of these methods and their sensitivity to the low-precision rounding errors,and demonstrate their performance in terms of accuracy and *** develop codes in FORTRAN and Julia to solve nonlinear systems of ODEs and PDEs using the mixed-precision additive Runge-Kutta(MP-ARK)*** convergence,accuracy,and runtime of these methods are *** show that for a given level of accuracy,suitably chosen MP-ARK methods may provide significant reductions in runtime.

关键词： Mixed precision Runge-Kutta methods Additive methods Accuracy

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Fabrication of Superhydrophobic Surfaces on Aluminum Alloy Via Electrodeposition of Copper Followed by Electrochemical Modification

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Nano-Micro Letters 2011年第3期3卷 160-165页

作者： Ying Huang D.K.Sarkar X-grant Chen University Research Center on Aluminum (CURAL) University of Qubec at Chicoutimi

Superhydrophobic aluminum surfaces have been prepared by means of electrodeposition of copper on aluminum surfaces, followed by electrochemical modification using stearic acid organic molecules. Scanning electron microscopy(SEM) images show that the electrodeposited copper films follow "island growth mode" in the form of microdots and their number densities increase with the rise of the negative deposition potentials. At an electrodeposition potential of-0.2 V the number density of the copper microdots are found to be 4.5×104cm^(-2)that are increased to 2.9×105cm^(-2)at a potential of-0.8 V. Systematically, the distances between the microdots are found to be reduced from 26.6 μm to 11.03 μm with the increase of negative electrochemical potential from-0.2 V to-0.8 V. X-ray diffraction(XRD) analyses have confirmed the formation of copper stearate on the stearic acid modified copper films. The roughness of the stearic acid modified electrodeposited copper films is found to increase with the increase in the density of the copper microdots. A critical copper deposition potential of-0.6 V in conjunction with the stearic acid modification provides a surface roughness of 6.2 μm with a water contact angle of 157?, resulting in superhydrophobic properties on the aluminum substrates.

关键词： Superhydrophobic aluminum surface Water contact angle Copper microdots Surface roughness Electrochemical modification

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