Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces

Copyright Clare and Holderied. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited

THE IMPACT OF GOVERNMENT SUBSIDIES ON THE OFF-FARM LABOR SUPPLY OF FARM OPERATORS

In addition to farm work, most farm families have someone working in off-farm employment. The purpose of this paper is to examine if, and how, the change in the nature of government farm programs in the recent past has affected the labor allocation of farm operator households to off-farm employment activities. The ultimate goal of this research is to investigate the potential impacts of decoupled payments on farm output.Labor and Human Capital,

Affirming the Absurd: Philosophy and Fiction

Contrary to some popular opinion, Camus is a serious philosopher who turns to the medium of the novel because only its format permits him to fully explore what it is to live. This paper examines the general themes of Camus’s work in relation to how the creative artist “lives” doubly, and how the novelist is in the best position of all—able to use negative thought to revolt against her or his situation. Furthermore, the author argues that absurd fiction opens up possibilities for the absurd reader in presenting a perspective that can affect the reader’s general sensibilities, including thoughts on ethics and chaos. In addition, the author draws parallels with phenomenology and uses ideas from Sartre, Ricœur, Heidegger, Merleau-Ponty, Wiggins, and Wittgenstein to illuminate Camus’ considerable value

REGIONAL DIFFERENCES IN THE CONTRIBUTION OF OFF-FARM WORK TO INCOME INEQUALITY

This paper uses the concept of the Gini Coefficient and data from the 1991 Farm Costs and Returns Survey (FCRS) to measure the role of off-farm income and that of other income sources in the size distribution of farm operator households' total personal income. Disaggregated FCRS data by region and by level of participation in off-farm employment show that nonparticipating farm operator households have, as a group, higher income inequality than participating households. The results also indicate that, irrespective of the off-farm work status of the farm operator household, the distribution of income among households in the North Central region is least unequal and that in the West is most unequal.Labor and Human Capital,

Shunning the scoop: Sidestepping the race to publish.

What happens when a researcher finds out that research very similar to their own is already being conducted? What if they find out that the said research is also very close to being published? First, there is probably anxiety and panic. Maybe, there are frantic calls to collaborators. Perhaps Twitter rants about the phenomenon of scooping that plagues all researchers, especially those early-career researchers who often feel they are in a race to get their best work out to the world

Biodiversity assessment across a dynamic riverine system: A comparison of eDNA metabarcoding versus traditional fish surveying methods

While many studies have considered the ability of eDNA to assess animal communities in lacustrine settings, fewer have considered riverine systems, particularly those spanning the environmental gradients present in large river basins. Such dynamic systems are challenging for eDNA biomonitoring due to differing eDNA transport distances in rivers and the effects of river chemistry. To address this challenge, we focused on the Thames River system, UK, which has exceptional historical fish records providing a baseline to test the accuracy of eDNA metabarcoding in recovering fish community structure across both fresh and tidal zones. Two primer sets targeting 12S and CO1 regions were used to capture fish communities across the Thames catchment, from the upper freshwaters to the mid estuary. eDNA was collected at 35 sites, 14 of which were simultaneously paired with traditional fish surveys for direct comparison. We demonstrated that eDNA metabarcoding consistently detected more freshwater species than traditional methods, despite extensive sampling effort using the latter. In contrast, metabarcoding did not perform as well as traditional approaches in estuarine waters, although results included the novel detection of the protected sea lamprey. We further demonstrated that minor variations in the recovery of all approaches would not impact on the assessment of simple ecological models of community structure and, thus, some variability between approaches should not be viewed as a serious hindrance to uptake. Rather, our findings support a growing consensus that eDNA can reliably detect fish communities across dynamic freshwater habitats

High frequency environmental DNA metabarcoding provides rapid and effective monitoring of fish community dynamics

Long-term monitoring is critical to measure the response of biodiversity patterns and processes to human-mediated environmental pressures. This is particularly pertinent in freshwaters, where recent estimates indicated a third of all fish species are threatened with extinction, making ongoing biomonitoring essential for conservation management. High frequency annual monitoring is critical for identifying temporal changes in fish community composition; however, traditional survey methods are typically less practical over such timeframes. While environmental (e)DNA measurement represents a potentially powerful tool for monitoring temporal community dynamics, studies are lacking. To address this deficit, we generated a high frequency time-series dataset of entire fish communities using eDNA metabarcoding, to directly assess the repeatability and sensitivity of this method for detecting annual population trends. We targeted two differing environments (freshwater vs. intertidal) within the Thames catchment, UK, where detailed historical records from traditional monitoring were available for comparison. To test how robust eDNA data is for inferring the known community, we applied a hierarchical, nested design encompassing short and longer-term variation in eDNA data. Our analyses showed that irrespective of environment, eDNA metabarcoding represented known seasonal shifts in fish communities, where increased relative read abundance of eDNA coincided with known migratory and spawning events, including those of the critically endangered native species Anguilla anguilla (European eel). eDNA species detections across a single year included over 75% of species recorded in a ca. 30-year historical dataset, highlighting the power of eDNA for species detection. Our findings provide greater insight into the utility of eDNA metabarcoding for recovering temporal trends in fish communities from dynamic freshwater systems and insight into the potential best sampling strategy for future eDNA surveys

Diet tracing in ecology: Method comparison and selection

1. Determining diet is a key prerequisite for understanding species interactions, food web structure and ecological dynamics. In recent years, there has been considerable development in both the methodology and application of novel and more traditional dietary tracing methods, yet there is no comprehensive synthesis that systematically and quantitatively compares among the different approaches. 2. Here we conceptualize diet tracing in ecology, provide recommendations for method selection, and illustrate the advantages of method integration. We summarize empirical evidence on how different methods quantify diet mixtures, by contrasting estimates of dietary proportions from multiple methods applied to the same consumer-resource datasets, or from experimental studies with known diet compositions. 3. Our data synthesis revealed an urgent need for more experiential comparisons among the dietary methods. The comparison of diet quantifications from field observations showed that different techniques aligned well in cases with less than six diet items, but diverged considerably when applied to more complex diet mixtures. 4. Efforts are ongoing to further advance dietary estimation, including how reliably compound specific stable isotope analyses and fatty acid profiles can quantify more prey items than bulk stable isotope analyses. Similarly, DNA analyses, which can depict trophic interactions at a higher resolution than any other methods, are generating new ways to better quantify diets and differentiate among life-stages of prey. Such efforts, combined with more empirical testing of each dietary method and establishment of open data repositories for dietary data, promise to greatly advance community and ecosystem ecology

The TLR4 D299G and T399I SNPs Are Constitutively Active to Up-Regulate Expression of Trif-Dependent Genes

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