Plains zebra (Equus quagga) adrenocortical activity increases during times of large aggregations in the Serengeti ecosystem

Adverse environmental stimuli (stressors) activate the hypothalamic-pituitary-adrenal axis and contribute to allostatic load. This study investigates the contribution of environmental stressors and life history stage to allostatic load in a migratory population of plains zebras (Equus quagga) in the Serengeti ecosystem, in Tanzania, which experiences large local variations in aggregation. We expected higher fGCM response to the environmental stressors of feeding competition, predation pressure and unpredictable social relationships in larger than in smaller aggregations, and in animals at energetically costly life history stages. As the study was conducted during the 2016 El Niño, we did not expect food quality of forage or a lack of water to strongly affect fGCM responses in the dry season. We measured fecal glucocorticoid metabolite (fGCM) concentrations using an enzyme immunoassay (EIA) targeting 11β-hydroxyetiocholanolone and validated its reliability in captive plains zebras. Our results revealed significantly higher fGCM concentrations 1) in large aggregations than in smaller groupings, and 2) in band stallions than in bachelor males. Concentrations of fGCM were not significantly higher in females at the energetically costly life stage of late pregnancy/lactation. The higher allostatic load of stallions associated with females, than bachelor males is likely caused by social stressors. In conclusion, migratory zebras have elevated allostatic loads in large aggregations that probably result from their combined responses to increased feeding competition, predation pressure and various social stressors. Further research is required to disentangle the contribution of these stressors to allostatic load in migratory populations.A grant from the Leibniz Gemeinschaft (SAW-2015-IZW-1 440) and the Leibniz Institute for Zoo and Wildlife Research.http://www.elsevier.com/locate/yhbeh2019-06-01hj2018Anatomy and PhysiologyMammal Research InstituteZoology and Entomolog

DNA sonication inverse PCR for genome scale analysis of uncharacterized flanking sequences

1. There are few available tools to comprehensively and economically identify uncharacterized flanking regions that are not extremely labour intensive and which exploit the advantages of emerging long‐read sequencing platforms. 2. We describe SIP; a sonication‐based inverse PCR high‐throughput sequencing strategy to investigate uncharacterized flanking region sequences, including those flanking mobile DNA. SIP combines unbiased fragmentation by sonication and target enrichment by coupling outward facing PCR priming with long‐read sequencing technologies. 3. We demonstrate the effectiveness of SIP by determining retroviral integrations which are high copy and challenging to characterize. We further describe SIP's workflow, examine retroviral (proviral) enrichment and characterize viral structural variants identified. When SIP was coupled with long‐read sequencing using the PacBio RS II platform, proviral integration was extensively characterized at high sequence depth per integration. By interrogating the sequence data, we were also able to test several intrinsic factors including SIP's propensity to form chimeric sequences and adapter ligation efficiencies. 4. SIP is an adaption of a traditional molecular biology technique that can be used to characterize any unknown genomic flanking sequence or to extend any sequence for which only minimal sequence information is available. SIP can be applied broadly to study complex biological systems such as mobile genetic elements with high throughput

Which Kubo formula gives the exact conductance of a mesoscopic disordered system?

In both research and textbook literature one often finds two ``different'' Kubo formulas for the zero-temperature conductance of a non-interacting Fermi system. They contain a trace of the product of velocity operators and single-particle (retarded and advanced) Green operators: $\text{Tr} (\hat{v}_x \hat{G}^r \hat{v}_x \hat{G}^a)$ or $\text{Tr} (\hat{v}_x \text{Im} \hat{G} \hat{v}_x \text{Im} \hat{G})$. The study investigates the relationship between these expressions, as well as the requirements of current conservation, through exact evaluation of such quantum-mechanical traces for a nanoscale (containing 1000 atoms) mesoscopic disordered conductor. The traces are computed in the semiclassical regime (where disorder is weak) and, more importantly, in the nonperturbative transport regime (including the region around localization-delocalization transition) where concept of mean free path ceases to exist. Since quantum interference effects for such strong disorder are not amenable to diagrammatic or nonlinear $\sigma$-model techniques, the evolution of different Green function terms with disorder strength provides novel insight into the development of an Anderson localized phase.Comment: 7 pages, 5 embedded EPS figures, final published version (note: PRB article has different title due to editorial censorship

Understanding the rift, the (still) uneasy bedfellows of History and Organization Studies

Although the use of History has become increasingly discussed and more widely applied within Organization Studies (OS), its relevance for OS still remains far from centrally accepted. This article historicizes the relationship between Sociology and History as a means of better understanding the tensions, perceived and real, that exist between History and Organization Studies. In particular we analyse three differences of epistemological standpoint (method, objectivity and usefulness) that are commonly seen as the foundation stones to incompatibility. Perhaps surprisingly for an analysis of apparent disciplinary differences, we find that these distinctions in terms of approach, once closely examined, are rarely clear-cut and historians and OS scholars are frequently closer in intention and method than they are distant. However, despite their large intersection of interests, we argue that important distinctions between the two fields should be acknowledged. Our contribution to the debates over the need for more historical approaches within OS therefore centrally rests on abandoning aspirations for fully integrative models of working together, in favour of cooperative modes that concede the fields’ differences. This subtle shift of emphasis will, we believe, greatly benefit OS scholars who hope to include historical perspectives in their work

Improved W boson mass measurement with the D0 detector

We have measured the W boson mass using the D0 detector and a data sample of 82 pb^-1 from the Tevatron collider. This measurement used W -> e nu decays, where the electron is close to a boundary of a central electromagnetic calorimeter module. Such 'edge' electrons have not been used in any previous D0 analysis, and represent a 14% increase in the W boson sample size. For these electrons, new response and resolution parameters are determined, and revised backgrounds and underlying event energy flow measurements are made. When the current measurement is combined with previous D0 W boson mass measurements, we obtain M_W = 80.483 +/- 0.084 GeV. The 8% improvement from the previous D0 measurement is primarily due to the improved determination of the response parameters for non-edge electrons using the sample of Z bosons with non-edge and edge electrons.Comment: submitted to Phys. Rev. D; 20 pages, 18 figures, 9 table

Microstructural simulation of dynamic recrystallization

A Monte Carlo model for dynamic recrystallization has been developed from earlier models used to simulate static recrystallization and grain growth. The model simulates dynamic recrystallization by adding recrystallization nuclei and stored energy continuously with time. The simulations reproduce many of the essential features of dynamic recrystallization. The stored energy of the system, which may be interpreted as a measure of the flow stress, goes through a maximum and then decays, monotonically under some conditions and in an oscillatory manner under others. The principle parameters that were studied were the rate of adding stored energy, [Delta]H, and the rate of adding nuclei, [Delta]N. As [Delta]H increases, for fixed [Delta]N, the oscillations decay more rapidly and the asymptotic energy rises. As [Delta]N increases again the oscillations decay more rapidly but the asymptotic stored energy decreases. The mean grain size of' the system also oscillates in a similar manner to the stored energy but out of phase by 90[deg]. The flow stress oscillations occurred for conditions which lead to both coarsening and refinement of the initial grain size. Necklacing of the prior grain structure by new grains were observed for low [Delta]H and high [Delta]N; it is, however, not an invariable feature of grain refinement. The initial grain size has a profound influence on the microstructure that evolves during the first cycle of recrystallization but at long times, a mean grain size is established which depends on the values of [Delta]H and [Delta]N alone. Comparison of the relationships between the energy storage rate, maximum and asymptotic stored energy and the grain size suggest that in physical systems the energy storage rate and the nucleation rate are coupled. Comparison of the simulation results with experimental trends suggests that the dependence of nucleation rate on storage should be positive but weak. All of these results were obtained without the addition of special parameters to the model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30270/1/0000671.pd

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02