Could increased cyanobacterial biomass following forest harvesting cause a reduction in zooplankton body size structure?

2006 ◽  
Vol 63 (10) ◽  
pp. 2308-2317 ◽  
Author(s):  
Anas Ghadouani ◽  
Bernadette Pinel-Alloul ◽  
Ellie E Prepas
Keyword(s):  
Large Scale ◽  
Size Structure ◽  
Forest Harvesting ◽  
Profound Change ◽  
Order Of Magnitude ◽  
Scale Experiment ◽  
Zooplankton Communities ◽  
Lake Systems ◽  
Possible Cause ◽  
Cyanobacterial Biomass

Changes in phytoplankton and zooplankton communities were studied in 16 lake-years during a large-scale experimental before–after study as part of the Terrestrial Riparian Organisms Lakes and Streams (TROLS) project. After forest harvesting, phytoplankton biomass and especially cyanobacterial biomass increased in some of the experimental lakes, up to an order of magnitude. Although the response of phytoplankton was not directly related to the intensity of forest harvesting, this large-scale experiment provided a unique opportunity for studying the effects of an increasing gradient in cyanobacterial biomass on zooplankton communities. Cladoceran size structure and biomass were negatively correlated with cyanobacterial biomass, suggesting that large cladocerans and especially daphnids were inhibited by the increase in cyanobacterial biomass. The increase in cyanobacterial biomass seems to have caused a significant reduction in the size structure of zooplankton communities. As no correlation was found between cladocerans and cyanotoxins, our results point more towards feeding inhibition by filamentous and colonial cyanobacteria as a possible cause for the decline in the size structure and biomass of zooplankton communities. These results suggest that the increase in cyanobacterial biomass is likely to cause a shift in the size of zooplankton communities, which will lead to a profound change in functioning of lake systems.

8. The Effect of Bythotrephes Longimanus on the Size Structure of Zooplankton Communities in the Muskoka Region, Ontario

2017 ◽  
Author(s):  
Johanna Pokorny
Keyword(s):  
Large Scale ◽  
Size Structure ◽  
Scale Effects ◽  
Regional Scale ◽  
Zooplankton Community ◽  
Zooplankton Abundance ◽  
Bythotrephes Longimanus ◽  
Zooplankton Species ◽  
Community Size ◽  
Zooplankton Communities

Invasive species are considered the greatest threat to aquatic ecosystem biodiversity. Bythotrephes longimanus, an exotic zooplankton species introduced to North America in the 1980s, is threatening the structure of indigenous aquatic ecosystems as it continues to invade inland Ontario lakes. As a predacious zooplankton species, B. longimanus has been shown to decrease zooplankton abundance, species richness and shift zooplankton community size structure in invaded lakes. However, much of the previous research concerning the predatory effects of B. longimanus has been on surveys of a small number of lakes or has been in controlled mesocosm or lab-based experiments. This study examines the effects of B. longimanus on the zooplankton community using size-structure characterizations (grouping individuals from the community based on size) as community measures for 311 lakes in the Muskoka Region, a highly invaded watershed in Southern Ontario. More specifically, the study explores the size-spectra of invaded versus uninvaded lakes, with reference to an array of environmental lake characteristics (water chemistry, lake morphometry,etc.), and the relevance of B. longimanus activity on the regional scale. By using such a large-scale survey we will be able to appreciate regional-scale effects, as well as encompass the multiple and more indirect trophic interactions that B. longimanus is likely having with the entire aquatic community. (Funding: NSERC & CAISN.)

scholarly journals A large-scale experiment finds no evidence that a seismic survey impacts a demersal fish fauna

2021 ◽  
Vol 118 (30) ◽  
pp. e2100869118
Author(s):  
Mark G. Meekan ◽  
Conrad W. Speed ◽  
Robert D. McCauley ◽  
Rebecca Fisher ◽  
Matthew J. Birt ◽  
...  
Keyword(s):  
Large Scale ◽  
Size Structure ◽  
Experimental Studies ◽  
Fish Fauna ◽  
Seismic Survey ◽  
Commercial Fisheries ◽  
Seismic Surveys ◽  
North West ◽  
Scale Experiment ◽  
Demersal Fishes

Seismic surveys are used to locate oil and gas reserves below the seabed and can be a major source of noise in marine environments. Their effects on commercial fisheries are a subject of debate, with experimental studies often producing results that are difficult to interpret. We overcame these issues in a large-scale experiment that quantified the impacts of exposure to a commercial seismic source on an assemblage of tropical demersal fishes targeted by commercial fisheries on the North West Shelf of Western Australia. We show that there were no short-term (days) or long-term (months) effects of exposure on the composition, abundance, size structure, behavior, or movement of this fauna. These multiple lines of evidence suggest that seismic surveys have little impact on demersal fishes in this environment.

scholarly journals Nebula: ultra-efficient mapping-free structural variant genotyper

2021 ◽  
Author(s):  
Parsoa Khorsand ◽  
Fereydoun Hormozdiari
Keyword(s):  
Large Scale ◽  
Structural Variants ◽  
Sequencing Technologies ◽  
Generic Framework ◽  
Common Genetic Variants ◽  
Order Of Magnitude ◽  
Complex Events ◽  
Comparable Accuracy ◽  
Using Data ◽  
Computational Resources

Abstract Large scale catalogs of common genetic variants (including indels and structural variants) are being created using data from second and third generation whole-genome sequencing technologies. However, the genotyping of these variants in newly sequenced samples is a nontrivial task that requires extensive computational resources. Furthermore, current approaches are mostly limited to only specific types of variants and are generally prone to various errors and ambiguities when genotyping complex events. We are proposing an ultra-efficient approach for genotyping any type of structural variation that is not limited by the shortcomings and complexities of current mapping-based approaches. Our method Nebula utilizes the changes in the count of k-mers to predict the genotype of structural variants. We have shown that not only Nebula is an order of magnitude faster than mapping based approaches for genotyping structural variants, but also has comparable accuracy to state-of-the-art approaches. Furthermore, Nebula is a generic framework not limited to any specific type of event. Nebula is publicly available at https://github.com/Parsoa/Nebula.

scholarly journals Marsh rabbit mortalities tie pythons to the precipitous decline of mammals in the Everglades

2015 ◽  
Vol 282 (1805) ◽  
pp. 20150120 ◽  
Author(s):  
Robert A. McCleery ◽  
Adia Sovie ◽  
Robert N. Reed ◽  
Mark W. Cunningham ◽  
Margaret E. Hunter ◽  
...  
Keyword(s):  
National Park ◽  
Large Scale ◽  
Ongoing Debate ◽  
Faunal Communities ◽  
Python Molurus ◽  
Scale Experiment ◽  
Precipitous Decline ◽  
Python Molurus Bivittatus ◽  
The Impact ◽  
Ecological Functioning

To address the ongoing debate over the impact of invasive species on native terrestrial wildlife, we conducted a large-scale experiment to test the hypothesis that invasive Burmese pythons ( Python molurus bivittatus ) were a cause of the precipitous decline of mammals in Everglades National Park (ENP). Evidence linking pythons to mammal declines has been indirect and there are reasons to question whether pythons, or any predator, could have caused the precipitous declines seen across a range of mammalian functional groups. Experimentally manipulating marsh rabbits, we found that pythons accounted for 77% of rabbit mortalities within 11 months of their translocation to ENP and that python predation appeared to preclude the persistence of rabbit populations in ENP. On control sites, outside of the park, no rabbits were killed by pythons and 71% of attributable marsh rabbit mortalities were classified as mammal predations. Burmese pythons pose a serious threat to the faunal communities and ecological functioning of the Greater Everglades Ecosystem, which will probably spread as python populations expand their range.

Efficient and High-Quality Seeded Graph Matching: Employing Higher-order Structural Information

2021 ◽  
Vol 15 (3) ◽  
pp. 1-31
Author(s):  
Haida Zhang ◽  
Zengfeng Huang ◽  
Xuemin Lin ◽  
Zhe Lin ◽  
Wenjie Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Graph Matching ◽  
Structural Information ◽  
Experimental Studies ◽  
Higher Order ◽  
Personalized Pagerank ◽  
Matching Accuracy ◽  
Approximation Techniques ◽  
Order Of Magnitude ◽  
Matching Score

Driven by many real applications, we study the problem of seeded graph matching. Given two graphs and , and a small set of pre-matched node pairs where and , the problem is to identify a matching between and growing from , such that each pair in the matching corresponds to the same underlying entity. Recent studies on efficient and effective seeded graph matching have drawn a great deal of attention and many popular methods are largely based on exploring the similarity between local structures to identify matching pairs. While these recent techniques work provably well on random graphs, their accuracy is low over many real networks. In this work, we propose to utilize higher-order neighboring information to improve the matching accuracy and efficiency. As a result, a new framework of seeded graph matching is proposed, which employs Personalized PageRank (PPR) to quantify the matching score of each node pair. To further boost the matching accuracy, we propose a novel postponing strategy, which postpones the selection of pairs that have competitors with similar matching scores. We show that the postpone strategy indeed significantly improves the matching accuracy. To improve the scalability of matching large graphs, we also propose efficient approximation techniques based on algorithms for computing PPR heavy hitters. Our comprehensive experimental studies on large-scale real datasets demonstrate that, compared with state-of-the-art approaches, our framework not only increases the precision and recall both by a significant margin but also achieves speed-up up to more than one order of magnitude.

Approximate Solution of Nonclassically Damped Systems

1991 ◽  
Author(s):  
F. Ma ◽  
J. H. Hwang
Keyword(s):  
Approximate Solution ◽  
Large Scale ◽  
Computational Effort ◽  
Frequency Separation ◽  
Common Procedure ◽  
Damping Matrix ◽  
Complex Modes ◽  
Modal Coupling ◽  
Order Of Magnitude ◽  
Damped Systems

Abstract In analyzing a nonclassically damped linear system, one common procedure is to neglect those damping terms which are nonclassical, and retain the classical ones. This approach is termed the method of approximate decoupling. For large-scale systems, the computational effort at adopting approximate decoupling is at least an order of magnitude smaller than the method of complex modes. In this paper, the error introduced by approximate decoupling is evaluated. A tight error bound, which can be computed with relative ease, is given for this method of approximate solution. The role that modal coupling plays in the control of error is clarified. If the normalized damping matrix is strongly diagonally dominant, it is shown that adequate frequency separation is not necessary to ensure small errors.

scholarly journals Fooled by facts: quantifying anchoring bias through a large-scale experiment

2022 ◽  
Author(s):  
Taha Yasseri ◽  
Jannie Reher
Keyword(s):  
Decision Making ◽  
Treatment Group ◽  
Field Experiment ◽  
Empirical Evidence ◽  
Large Scale ◽  
Complex Relationship ◽  
Great Care ◽  
The Future ◽  
Anchoring Bias ◽  
Scale Experiment

AbstractThrough a large-scale online field experiment, we provide new empirical evidence for the presence of the anchoring bias in people’s judgement due to irrational reliance on a piece of information that they are initially given. The comparison of the anchoring stimuli and respective responses across different tasks reveals a positive, yet complex relationship between the anchors and the bias in participants’ predictions of the outcomes of events in the future. Participants in the treatment group were equally susceptible to the anchors regardless of their level of engagement, previous performance, or gender. Given the strong and ubiquitous influence of anchors quantified here, we should take great care to closely monitor and regulate the distribution of information online to facilitate less biased decision making.

scholarly journals Psychometric properties of the Adelaide Diagnostic Learning Inventory - Brief (ADLIB)

2019 ◽  
Author(s):  
Harry Minas
Keyword(s):  
Academic Performance ◽  
Learning Styles ◽  
University Students ◽  
Psychometric Properties ◽  
Factor Structure ◽  
Life Stress ◽  
Large Scale ◽  
Well Being ◽  
Factor Congruence ◽  
Order Of Magnitude

Abstract Objective: There has been increased attention in recent years to mental health, quality of life, stress and academic performance among university students, and the possible influence of learning styles. Brief reliable questionnaires are useful in large-scale multivariate research designs, such as the largely survey-based research on well-being and academic performance of university students. The objective of this study was to examine the psychometric properties of a briefer version of the 39-item Adelaide Diagnostic Learning Inventory. Results: In two survey samples - medical and physiotherapy students - a 21-item version Adelaide Diagnostic Learning Inventory - Brief (ADLIB) was shown to have the same factor structure as the parent instrument, and the factor structure of the brief instrument was found to generalise across students of medicine and physiotherapy. Sub-scale reliability estimations were in the order of magnitude of the parent instrument. Sub-scale inter-correlations, inter-factor congruence coefficients, and correlations between ADLIB sub-scale scores and several external measures provide support support for the construct and criterion validity of the instrument.

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