Resource matching across habitats is limited by competition at patch scales in an estuarine-opportunist fish

2005 ◽  
Vol 62 (4) ◽  
pp. 913-924 ◽  
Author(s):  
Karl M Polivka
Keyword(s):  
Interspecific Competition ◽  
Resource Availability ◽  
Large Scale ◽  
Substantial Reduction ◽  
Fish Growth ◽  
Matching Theory ◽  
Temporal Scales ◽  
Specific Effects ◽  
Resource Matching ◽  
Number Of Individuals

I used field observations, assays, and experiments with the euryhaline cottid Cottus aleuticus to evaluate the extent to which average resource availability drives the large-scale distribution of these fish among upstream and estuarine habitats and how interspecific competition from a congener affects its performance in the estuary. Population densities of C. aleuticus were only consistent with resource densities across years during two of five study years, indicating a lack of resource matching at large temporal scales. On shorter temporal scales, fish growth rates that were two to three times higher in the estuary compared with the stream were inconsistent with the predictions of resource matching theory. A manipulation of C. aleuticus density showed that the estuary could support at least twice the number of individuals that occurred there; thus, the profitable estuary is underutilized. Interspecific competition with Cottus asper was partially responsible for this underutilization as indicated by a substantial reduction in growth and condition among C. aleuticus individuals in experimental manipulations that compared intra- and inter-specific effects. Observed spatial overlap between these two cottids combined with the results of the competition experiment suggests that C. aleuticus is more strongly limited in its ability to use estuarine habitats opportunistically by interspecific competition than by intraspecific competition.

Dehydroepiandrosterone (DHEA) and its Sulphate (DHEAS) in Alzheimer’s Disease

2020 ◽  
Vol 17 (2) ◽  
pp. 141-157 ◽  
Author(s):  
Dubravka S. Strac ◽  
Marcela Konjevod ◽  
Matea N. Perkovic ◽  
Lucija Tudor ◽  
Gordana N. Erjavec ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Therapeutic Potential ◽  
Relevant Literature ◽  
Comprehensive Overview ◽  
Brain Functions ◽  
Specific Effects ◽  
And Behavior

Background: Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer’s disease. Objective: The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer’s disease. Method: PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles. Results: We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer’s disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications. Conclusion: Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer’s disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.

Distributed learning with indefinite kernels

2019 ◽  
Vol 17 (06) ◽  
pp. 947-975 ◽  
Author(s):  
Lei Shi
Keyword(s):  
Large Scale ◽  
Substantial Reduction ◽  
Computation Time ◽  
Distributed Learning ◽  
Rates Of Convergence ◽  
Regression Problem ◽  
Data Set ◽  
Regularization Scheme ◽  
Original Algorithm ◽  
Indefinite Kernel

We investigate the distributed learning with coefficient-based regularization scheme under the framework of kernel regression methods. Compared with the classical kernel ridge regression (KRR), the algorithm under consideration does not require the kernel function to be positive semi-definite and hence provides a simple paradigm for designing indefinite kernel methods. The distributed learning approach partitions a massive data set into several disjoint data subsets, and then produces a global estimator by taking an average of the local estimator on each data subset. Easy exercisable partitions and performing algorithm on each subset in parallel lead to a substantial reduction in computation time versus the standard approach of performing the original algorithm on the entire samples. We establish the first mini-max optimal rates of convergence for distributed coefficient-based regularization scheme with indefinite kernels. We thus demonstrate that compared with distributed KRR, the concerned algorithm is more flexible and effective in regression problem for large-scale data sets.

scholarly journals Is Agriculture Always a GHG Emitter? A Combination of Eddy Covariance and Life Cycle Assessment Approaches to Calculate C Intake and Uptake in a Kiwifruit Orchard

2021 ◽  
Vol 13 (12) ◽  
pp. 6906
Author(s):  
Federica Rossi ◽  
Camilla Chieco ◽  
Nicola Di Virgilio ◽  
Teodoro Georgiadis ◽  
Marianna Nardino
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Greenhouse Gases ◽  
Eddy Covariance ◽  
Large Scale ◽  
Cropping Systems ◽  
Substantial Reduction ◽  
Co2 Absorption ◽  
Positive Contribution ◽  
Efficiency Ratio

While a substantial reduction of GHG (greenhouse gases) is urged, large-scale mitigation implies a detailed and holistic knowledge on the role of specific cropping systems, including the effect of management choices and local factors on the final balance between emissions and removals, this last typical of cropping systems. Here, a conventionally managed irrigated kiwifruit orchard has been studied to assess its greenhouse gases emissions and removals to determine its potential action as a C sink or, alternately, as a C source. The paper integrates two independent approaches. Biological CO2 fluxes have been monitored during 2012 using the micrometeorological Eddy covariance technique, while life cycle assessment quantified emissions derived from the energy and material used. In a climatic-standard year, total GHG emitted as consequence of the management were 4.25 t CO2-eq−1 ha−1 yr−1 while the net uptake measured during the active vegetation phase was as high as 4.9 t CO2 ha−1 yr−1. This led to a positive contribution of the crop to CO2 absorption, with a 1.15 efficiency ratio (sink-source factor defined as t CO2 stored/t CO2 emitted). The mitigating activity, however, completely reversed under extremely unfavorable climatic conditions, such as those recorded in 2003, when the efficiency ratio became 0.91, demonstrating that the occurrence of hotter and drier conditions are able to compromise the capability of Actinidia to offset the GHG emissions, also under appropriate irrigation.

scholarly journals Active Dispersal of an Aquatic Invader Determined by Resource and Flow Conditions

2011 ◽  
Vol 33 ◽  
pp. 137-146
Author(s):  
Adam Sepulveda ◽  
Laurie Marczak
Keyword(s):  
Flow Velocity ◽  
Resource Availability ◽  
Effective Means ◽  
Movement Direction ◽  
Potential Vector ◽  
Movement Rates ◽  
Population Spread ◽  
Fast Flow ◽  
Initial Starting ◽  
Number Of Individuals

New Zealand mudsnails (NZMS) have spread rapidly across the western United States, but little is known about mechanisms that drive their spread within invaded streams. We used a field experiment to test if upstream movement is a potential vector of NZMS spread and how this movement is modified by flow velocity and resource availability. We found movement direction and rates were related to flow velocity, while resource availability influenced the number of individuals that moved. In slow-flow treatments, individuals moved upstream at faster rates (~ 3 m/hr) than previously recorded for this species. In fast-flow treatments, most individuals were dislodged downstream and upstream movement rates were less than 2 m/hr. In low-resource treatments, individuals were more likely to move away from their initial starting locations. We suggest that upstream movement may be important in establishing new populations within local invasions and that increases in flow velocity may be an effective means to slow the upstream spread of NZMS. The surprisingly fast movements that we recorded predict greater distribution of NZMS within invaded streams than has actually occurred, which suggests that factors in addition to NZMS movement rate may limit population spread.

scholarly journals Knockdown of 60S ribosomal protein L14-2 reveals their potential regulatory roles to enhance drought and salt tolerance in cotton

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Margaret Linyerera SHIRAKU ◽  
Richard Odongo MAGWANGA ◽  
Xiaoyan CAI ◽  
Joy Nyangasi KIRUNGU ◽  
Yanchao XU ◽  
...  
Keyword(s):  
Salt Stress ◽  
Ribosomal Protein ◽  
Large Scale ◽  
Natural Fiber ◽  
Substantial Reduction ◽  
Regulatory Elements ◽  
Scale Production ◽  
Drought And Salt Tolerance ◽  
Drought And Salt Stress ◽  
Effects Of Drought

Abstract Background Cotton is a valuable economic crop and the main significant source of natural fiber for textile industries globally. The effects of drought and salt stress pose a challenge to strong fiber and large-scale production due to the ever-changing climatic conditions. However, plants have evolved a number of survival strategies, among them is the induction of various stress-responsive genes such as the ribosomal protein large (RPL) gene. The RPL gene families encode critical proteins, which alleviate the effects of drought and salt stress in plants. In this study, comprehensive and functional analysis of the cotton RPL genes was carried out under drought and salt stresses. Results Based on the genome-wide evaluation, 26, 8, and 5 proteins containing the RPL14B domain were identified in Gossypium hirsutum, G. raimondii, and G. arboreum, respectively. Furthermore, through bioinformatics analysis, key cis-regulatory elements related to RPL14B genes were discovered. The Myb binding sites (MBS), abscisic acid-responsive element (ABRE), CAAT-box, TATA box, TGACG-motif, and CGTCA-motif responsive to methyl jasmonate, as well as the TCA-motif responsive to salicylic acid, were identified. Expression analysis revealed a key gene, Gh_D01G0234 (RPL14B), with significantly higher induction levels was further evaluated through a reverse genetic approach. The knockdown of Gh_D01G0234 (RPL14B) significantly affected the performance of cotton seedlings under drought/salt stress conditions, as evidenced by a substantial reduction in various morphological and physiological traits. Moreover, the level of the antioxidant enzyme was significantly reduced in VIGS-plants, while oxidant enzyme levels increased significantly, as demonstrated by the higher malondialdehyde concentration level. Conclusion The results revealed the potential role of the RPL14B gene in promoting the induction of antioxidant enzymes, which are key in oxidizing the various oxidants. The key pathways need to be investigated and even as we exploit these genes in the developing of more stress-resilient cotton germplasms.

scholarly journals Foraging theory upscaled: the behavioural ecology of herbivore movement

2010 ◽  
Vol 365 (1550) ◽  
pp. 2267-2278 ◽  
Author(s):  
N. Owen-Smith ◽  
J. M. Fryxell ◽  
E. H. Merrill
Keyword(s):  
Seasonal Cycle ◽  
Large Scale ◽  
Diel Activity ◽  
Patch Selection ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Gps Collars ◽  
Activity Schedule ◽  
Spatio Temporal ◽  
Time And Energy

We outline how principles of optimal foraging developed for diet and food patch selection might be applied to movement behaviour expressed over larger spatial and temporal scales. Our focus is on large mammalian herbivores, capable of carrying global positioning system (GPS) collars operating through the seasonal cycle and dependent on vegetation resources that are fixed in space but seasonally variable in availability and nutritional value. The concept of intermittent movement leads to the recognition of distinct movement modes over a hierarchy of spatio-temporal scales. Over larger scales, periods with relatively low displacement may indicate settlement within foraging areas, habitat units or seasonal ranges. Directed movements connect these patches or places used for other activities. Selection is expressed by switches in movement mode and the intensity of utilization by the settlement period relative to the area covered. The type of benefit obtained during settlement periods may be inferred from movement patterns, local environmental features, or the diel activity schedule. Rates of movement indicate changing costs in time and energy over the seasonal cycle, between years and among regions. GPS telemetry potentially enables large-scale movement responses to changing environmental conditions to be linked to population performance.

Variant calling and quality control of large-scale human genome sequencing data

2019 ◽  
Vol 3 (4) ◽  
pp. 399-409 ◽  
Author(s):  
Brandon Jew ◽  
Jae Hoon Sul
Keyword(s):  
Quality Control ◽  
Genome Sequencing ◽  
Genetic Variants ◽  
Large Scale ◽  
Variant Calling ◽  
Sequencing Data ◽  
Computational Approaches ◽  
Sequencing Errors ◽  
Human Genome Sequencing ◽  
Number Of Individuals

Abstract Next-generation sequencing has allowed genetic studies to collect genome sequencing data from a large number of individuals. However, raw sequencing data are not usually interpretable due to fragmentation of the genome and technical biases; therefore, analysis of these data requires many computational approaches. First, for each sequenced individual, sequencing data are aligned and further processed to account for technical biases. Then, variant calling is performed to obtain information on the positions of genetic variants and their corresponding genotypes. Quality control (QC) is applied to identify individuals and genetic variants with sequencing errors. These procedures are necessary to generate accurate variant calls from sequencing data, and many computational approaches have been developed for these tasks. This review will focus on current widely used approaches for variant calling and QC.

scholarly journals Differential success in sampling of Atlantic Forest amphibians among different periods of the day

2015 ◽  
Vol 75 (2) ◽  
pp. 261-267 ◽  
Author(s):  
CFD. Rocha ◽  
CC. Siqueira ◽  
CV. Ariani ◽  
D. Vrcibradic ◽  
DM. Guedes ◽  
...  
Keyword(s):  
Large Scale ◽  
Atlantic Rainforest ◽  
Southeastern Brazil ◽  
Sampling Effort ◽  
Amphibian Species ◽  
Field Surveys ◽  
Future Studies ◽  
Pooled Data ◽  
Large Scale Field ◽  
Number Of Individuals

In general, anurans tend to be nocturnal, though diurnal activity is characteristic of some groups. Studies show that frog activity may be inferred based on the number of individuals collected at different periods of the day, during large-scale field surveys. We investigated the best period of the day to conduct amphibian sampling in nine Atlantic Rainforest areas in southeastern Brazil, based on intensive field surveys. At each locality we employed similar sampling effort during diurnal, crepuscular and nocturnal searches (totaling 704.5 sampling hours). We pooled data from all localities for each period and estimated the proportion of frogs of each species active at each period based on the total number of individuals and on the number of species found during all surveys for that period. We recorded a total of 817 individual frogs from 69 species. Species richness was highest at night (median = 12 species), intermediate at dusk (median = 8), and lowest during the day (median = 4). The percentage of the total number of individual frogs found (pooled species) was highest during the night (ca. 53%) and lowest during the day (ca. 14%). Analyzing each species separately, the number of individuals recorded was consistently higher at dusk and night for most species. Our study evidences a trend for nocturnal activity for most Atlantic Rainforest frogs, with few species having primarily diurnal habits. Those results may favor future studies and conservation efforts for amphibian species.

Australia’s economic transition, unemployment, suicide and mental health needs

2016 ◽  
Vol 51 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Nicholas Myles ◽  
Matthew Large ◽  
Hannah Myles ◽  
Robert Adams ◽  
Dennis Liu ◽  
...  
Keyword(s):  
Mental Health ◽  
Mental Illness ◽  
Psychological Distress ◽  
Large Scale ◽  
Manufacturing Industry ◽  
Job Loss ◽  
Substantial Reduction ◽  
Public Mental Health ◽  
Public Mental Health Care ◽  
The Impact

Objective: There have been substantial changes in workforce and employment patterns in Australia over the past 50 years as a result of economic globalisation. This has resulted in substantial reduction in employment in the manufacturing industry often with large-scale job losses in concentrated sectors and communities. Large-scale job loss events receive significant community attention. To what extent these mass unemployment events contribute to increased psychological distress, mental illness and suicide in affected individuals warrants further consideration. Methods: Here we undertake a narrative review of published job loss literature. We discuss the impact that large-scale job loss events in the manufacturing sector may have on population mental health, with particular reference to contemporary trends in the Australian economy. We also provide a commentary on the expected outcomes of future job loss events in this context and the implications for Australian public mental health care services. Results and conclusion: Job loss due to plant closure results in a doubling of psychological distress that peaks 9 months following the unemployment event. The link between job loss and increased rates of mental illness and suicide is less clear. The threat of impending job loss and the social context in which job loss occurs has a significant bearing on psychological outcomes. The implications for Australian public mental health services are discussed.

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