942 research outputs found
High interindividual variability in habitat selection and functional habitat relationships in European nightjars over a period of habitat change
An animal's choice of foraging habitat reflects its response to environmental cues and is likely to vary among individuals in a population. Analyzing the magnitude of individual habitat selection can indicate how resilient populations may be to anthropogenic habitat change, where individually varying, broadly generalist populations have the potential to adjust their behavior. We collected GPS point data from 39 European nightjars (Caprimulgus europaeus) at a UK breeding site where restoration measures have altered large areas of habitat between breeding seasons. We calculated individual habitat selection over four breeding seasons to observe changes that might align with change in habitat. We also analyzed change in home range size in line with change in habitat availability, to examine functional relationships that can represent trade‐offs made by the birds related to performance of the habitat.Individual explained more of the variation in population habitat selection than year for most habitat types. Individuals differed in the magnitude of their selection for different habitat types, which created a generalist population composed of both generalist and specialist individuals. Selection also changed over time but only significantly for scrub habitat (60% decrease in selection over 4 years). Across the population, individual home range size was 2% smaller where availability of cleared habitat within the home range was greater, but size increased by 2% where the amount of open water was higher, indicating the presence of trade‐offs related to habitat availability. These results highlight that using individual resource selection and specialization measures, in conjunction with functional responses to change, can lead to better understanding of the needs of a population. Pooling specialist and generalist individuals for analysis could hide divergent responses to change and consequently obscure information that could be important in developing effective conservation strategies
Proteomic and Membrane Lipid Correlates of Reduced Host Defense Peptide
We previously described a transposon mutant in Staphylococcus aureus strain SH1000 that exhibited reduced susceptibility to cationic thrombin-induced platelet microbicidal proteins (tPMPs). The transposon insertion site was mapped to the gene snoD, the staphylococcal nuo orthologue. Hence, further studies have been performed to understand how this mutation impacts susceptibility to tPMP, by comparing proteomics profiling and membrane lipid analyses of the parent vs. mutant strains. Surprisingly, the mutant showed differential regulation of only a single protein when cultivated aerobically (FadB), and only a small number of proteins under anaerobic growth conditions (AdhE, DapE, Ddh, Ald1, IlvA1, AgrA, Rot, SA2366, and SA2367). Corresponding to FadB impact on lipid remodeling, membrane fatty acid analyses showed that the snoD mutant contained more short chain anteiso-, but fewer short chain iso-branched chain fatty acids under both aerobic and anaerobic conditions vs. the parental strain. Based upon these proteomic and membrane compositional data, a hypothetical "network" model was developed to explain the impact of the snoD mutation upon tPMP susceptibility
The effect of memory on relaxation in a scalar field theory
We derive a kinetic equation with a non-Markovian collision term which
includes a memory effect, from Kadanoff-Baym equations in theory
within the three-loop level for the two-particle irreducible (2PI) effective
action. The memory effect is incorporated into the kinetic equation by a
generalized Kadanoff-Baym ansatz.Based on the kinetic equations with and
without the memory effect, we investigate an influence of this effect on decay
of a single particle excitation with zero momentum in 3+1 dimensions and the
spatially homogeneous case. Numerical results show that, while the time
evolution of the zero mode is completely unaffected by the memory effect due to
a separation of scales in the weak coupling regime, this effect leads first to
faster relaxation than the case without it and then to slower relaxation as the
coupling constant increases.Comment: 12 pages, 6 eps figure
First principles calculation of structural and magnetic properties for Fe monolayers and bilayers on W(110)
Structure optimizations were performed for 1 and 2 monolayers (ML) of Fe on a
5 ML W(110) substrate employing the all-electron full-potential linearized
augmented plane-wave (FP-LAPW) method. The magnetic moments were also obtained
for the converged and optimized structures. We find significant contractions
( 10 %) for both the Fe-W and the neighboring Fe-Fe interlayer spacings
compared to the corresponding bulk W-W and Fe-Fe interlayer spacings. Compared
to the Fe bcc bulk moment of 2.2 , the magnetic moment for the surface
layer of Fe is enhanced (i) by 15% to 2.54 for 1 ML Fe/5 ML W(110), and
(ii) by 29% to 2.84 for 2 ML Fe/5 ML W(110). The inner Fe layer for 2
ML Fe/5 ML W(110) has a bulk-like moment of 2.3 . These results agree
well with previous experimental data
Efficiency of disinfectants against Rotavirus in the presence and absence of organic matter
Rotavirus is an enteric pathogen that causes morbidity and mortality in young mammals, including pigs. Outbreaks of rotavirus on commercial farms have a significant economic impact in terms of losses in production. Effective cleaning and disinfection along with good farm management can reduce rotavirus contamination in the environment, and decrease the chance of outbreaks of disease. This study investigated the efficacy of six commercial disinfectants against MS2 bacteriophage and Group A porcine rotavirus, in the presence of high and low levels of organic matter to simulate the farm environment. A phenolic-based disinfectant (Bi-OO-cyst) was effective at all levels of organic matter concentrations. Iodophore based disinfectants did not have a significant virucidal effect against rotavirus under any conditions. For peroxygen compound-based disinfectants and glutaraldehyde-based disinfectants, organic matter load made a significant difference in reducing efficacy. This highlights the importance of thorough cleaning with detergent before disinfection to reduce viral contamination on the farm and decrease rotavirus disease incidence in pigs
The Lantern Vol. 49, No. 1, Fall 1982
• The Dormant Tree • Les Maitres des mots... • The Bartender • Time • Small Silent Creatures • Appreciation de la vie • Mon Seigneur, Mon Ami • In Gratitude • Cathedral • Child • Grow Old With Me • To Keep The Land • Lesetta • No Answer • The Hunt • You Came to Me • A Day in the Life of a Thought • Revenge • The Dance • Unclaimed • Where e\u27er There Be a Reason • Pour le coin • Thinking of You • You Were The Onehttps://digitalcommons.ursinus.edu/lantern/1121/thumbnail.jp
Business group affiliation and foreign subsidiary performance
Research Summary Business group (BG) affiliation affects the strategic behavior and performance of firms. Until now it has been theoretically unclear and insufficiently empirically tested whether affiliation advantages extend to the foreign subsidiaries of group members. We attempt to determine if they do, and if so, to identify the boundary conditions that matter. We analyze a large panel of 451 foreign subsidiaries of 136 Indian multinational firms over the 2003-2012 period and find that BG affiliation does enhance foreign subsidiary performance when host-market institutions are weak and when the parent is in manufacturing. Managerial Summary Our research speaks directly to managers of multinational firms who seek to leverage the benefits of BG affiliation across national borders. We show that BG affiliation is only beneficial when the foreign subsidiary is located in a country characterized by weak institutions and when the parent is in manufacturing. If, on the other hand, the foreign subsidiary is in a country with well-functioning institutions and the parent in services, managers will not be able to count on BG advantages, rather they will have to develop competitive capabilities locally, that is, the foreign subsidiary will have to function more like a standalone firm
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A non-equilibrium neutral model for analysing cultural change
Neutral evolution is a frequently used model to analyse changes in frequencies of cultural variants over time. Variants are chosen to be copied according to their relative frequency and new variants are introduced by a process of random mutation. Here we present a non-equilibrium neutral model which accounts for temporally varying population sizes and mutation rates and makes it possible to analyse the cultural system under consideration at any point in time. This framework gives an indication whether observed changes in the frequency distributions of a set of cultural variants between two time points are consistent with the random copying hypothesis. We find that the likelihood of the existence of the observed assemblage at the end of the considered time period (expressed by the probability of the observed number of cultural variants present in the population during the whole period under neutral evolution) is a powerful indicator of departures from neutrality. Further, we study the effects of frequency-dependent selection on the evolutionary trajectories and present a case study of change in the decoration of pottery in early Neolithic Central Europe. Based on the framework developed we show that neutral evolution is not an adequate description of the observed changes in frequency
Adaptable Overhanging Carboxylic Acid Porphyrins Towards Molecular Assemblies through Unusual Coordination Modes
International audienceA new family of strap porphyrins exhibiting out/in overhanging carboxylic acid stereoisomerism, has been synthesized and investigated for its coordination properties. Their 5,10 linkage allows a significant flexibility of the strap which exhibits various degrees of angulation relatively to the mean porphyrin plane, making the ligand adjustable to the metal it binds. Notably, in the case of Bi(III), a second sphere of coordination plays a crucial role for the side selective insertion of the large metal ion. As a result, inward and outward orientation of the overhanging carboxylic acid function can be tuned, which is of interest for supramolecular coordination assemblies
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