Causes of exotic bird establishment across oceanic islands

The probability that exotic species will successfully establish viable populations varies between regions, for reasons that are currently unknown. Here, we use data for exotic bird introductions to 41 oceanic islands and archipelagos around the globe to test five hypotheses for this variation: the effects of introduction effort, competition, predation, human disturbance and habitat diversity (island biogeography). Our analyses demonstrate the primary importance of introduction effort for avian establishment success across regions, in concordance with previous analyses within regions. However, they also reveal a strong negative interaction across regions between establishment success and predation; exotic birds are more likely to fail on islands with species-rich mammalian predator assemblages

Изменение египетских мер зерна

Статья посвящена обзору мер зерна, использовавшихся в эллинистическом и римском Египте.Приложение: с. 373-375

Flavor changing single top quark production channels at e^+e^- colliders in the effective Lagrangian description

We perform a global analysis of the sensitivity of LEP2 and e^+e^- colliders with a c.m. energy in the range 500 - 2000 GeV to new flavor-changing single top quark production in the effective Lagrangian approach. The processes considered are sensitive to new flavor-changing effective vertices such as Ztc, htc, four-Fermi tcee contact terms as well as a right-handed Wtb coupling. We show that e^+ e^- colliders are most sensitive to the physics responsible for the contact tcee vertices. For example, it is found that the recent data from the 189 GeV LEP2 run can be used to rule out any new flavor physics that can generate these four-Fermi operators up to energy scales of \Lambda > 0.7 - 1.4 TeV, depending on the type of the four-Fermi interaction. We also show that a corresponding limit of \Lambda > 1.3 - 2.5 and \Lambda > 17 - 27 TeV can be reached at the future 200 GeV LEP2 run and a 1000 GeV e^+e^- collider, respectively. We note that these limits are much stronger than the typical limits which can be placed on flavor diagonal four-Fermi couplings. Similar results hold for \mu^+\mu^- colliders and for tu(bar) associated production. Finally we briefly comment on the necessity of measuring all flavor-changing effective vertices as they can be produced by different types of heavy physics.Comment: 34 pages, plain latex, 7 figures embadded in the text using epsfig. Added new references and discussions regarding their relevance to the paper. Added more comments on the comparison between flavor-changing and flavor-diagonal contact terms and on the importance of measuring the Ztc verte

Comparative effectiveness of dual vs. single-action antidepressants on HIV clinical outcomes in HIV-infected people with depression

Objective: Depression is highly prevalent among people living with HIV/AIDS (PLWHA) and has deleterious effects on HIV clinical outcomes. We examined changes in depression symptoms, viral suppression, and CD4 + T cells/μl among PLWHA diagnosed with depression who initiated antidepressant treatment during routine care, and compared the effectiveness of dual-action and single-action antidepressants for improving those outcomes. Design: Comparative effectiveness study of new user dual-action or single-action antidepressant treatment episodes occurring from 2004 to 2014 obtained from the Center for AIDS Research Network of Integrated Clinical Systems. Methods: We identified new user treatment episodes with no antidepressant use in the preceding 90 days. We completed intent-to-treat and per protocol evaluations for the main analysis. Primary outcomes, were viral suppression (HIV viral load <200 copies/ml) and CD4 + T cells/μl. In a secondary analysis, we used the Patient Health Questionnaire-9 (PHQ-9) to evaluate changes in depression symptoms and remission (PHQ <5). Generalized estimating equations with inverse probability of treatment weights were fitted to estimate treatment effects. Results: In weighted intent-to-treat analyses, the probability of viral suppression increased 16% after initiating antidepressants [95% confidence interval=(1.12, 1.20)]. We observed an increase of 39 CD4 + T cells/μl after initiating antidepressants (30, 48). Both the frequency of remission from depression and PHQ-9 scores improved after antidepressant initiation. Comparative effectiveness estimates were null in all models. Conclusion: Initiating antidepressant treatment was associated with improvements in depression, viral suppression, and CD4 + T cells/μl, highlighting the health benefits of treating depression in PLWHA. Dual and single-action antidepressants had comparable effectiveness

Excess adiposity and low physical fitness hamper Supine-to-Stand test performance among sedentary adolescents

Objective: The aim of this study was to analyze the relationship between body adiposity and physical fitness with performance in the Supine-to-Stand test (STS-test) in sedentary adolescents. Methods: Sixty-two adolescents, of both sexes, between 10 and 16 years old, participated in the study. Body mass (BM), height, waist circumference (WC), fat mass (FM), fat-free mass (FFM), right and left handgrip strength (HGS-right, HGS-left), abdominal resistance (ABDO), flexibility (FLEX), and cardiorespiratory fitness (VO2peak) were measured. Body mass index (BMI), z-score BMI (BMI-z), tri-ponderal mass index (TMI) and waist-to-height ratio (WHtR) were calculated. The STS-test was applied to evaluate the STS-MC by the movement patterns in the execution of the test. The STS-time in seconds (s) was categorized into terciles: fast (FG  2.6 s). One-way ANOVA, Chi-square, Spearman's correlation coefficient as well as non-parametric tests were used, with significance p ≤ 0.05. Results: The SG presented higher BMI, BMI-z, TMI, WHtR, FM, %FM, as well as lower averages for %FFM, HGS-right, HGS-left, FLEX, ABDO, VO2peak, VO2peak relative to BM (VO2peakBM) in relation to GF. The BMI, BMI-z, TMI, WC, WHtR and FM showed moderate and direct correlations with STS-time and inverse with STS-MC (p < 0.01). HGS-right, HGS-left, ABDO, and VO2peakBM showed moderate and an inverse correlation with STS-time (p < 0.05). The VO2peakBM was moderate and with direct correlations to STS-MC (p < 0.01). Conclusion: It is concluded that excess fat and low physical fitness hamper STS-test performance. Therefore, the STS-test can be used for screening students to assess MC

(Borel) convergence of the variationally improved mass expansion and the O(N) Gross-Neveu model mass gap

We reconsider in some detail a construction allowing (Borel) convergence of an alternative perturbative expansion, for specific physical quantities of asymptotically free models. The usual perturbative expansions (with an explicit mass dependence) are transmuted into expansions in 1/F, where $F \sim 1/g(m)$ for $m \gg \Lambda$ while $F \sim (m/\Lambda)^\alpha$ for m \lsim \Lambda, $\Lambda$ being the basic scale and $\alpha$ given by renormalization group coefficients. (Borel) convergence holds in a range of $F$ which corresponds to reach unambiguously the strong coupling infrared regime near $m\to 0$, which can define certain "non-perturbative" quantities, such as the mass gap, from a resummation of this alternative expansion. Convergence properties can be further improved, when combined with $\delta$ expansion (variationally improved perturbation) methods. We illustrate these results by re-evaluating, from purely perturbative informations, the O(N) Gross-Neveu model mass gap, known for arbitrary $N$ from exact S matrix results. Comparing different levels of approximations that can be defined within our framework, we find reasonable agreement with the exact result.Comment: 33 pp., RevTeX4, 6 eps figures. Minor typos, notation and wording corrections, 2 references added. To appear in Phys. Rev.

Topochemical Synthesis of Single-Crystalline Hydrogen-Bonded Cross-Linked Organic Frameworks and Their Guest-Induced Elastic Expansion

Covalently linked single-crystalline porous organic materials are highly desired for structure-property analysis; however, periodically polymerizing organic entities into high dimensional networks is challenging. Here, we report a series of topologically divergent single-crystalline hydrogen-bonded cross-linked organic frameworks (HCOFs) with visible guest-induced elastic expansions, which mutually integrate high structural order and high flexibility into one framework. These HCOFs are synthesized by photo-cross-linking molecular crystals with alkyldithiols of different chain lengths. Their detailed structural information was revealed by single-crystal X-ray analysis and experimental investigations of HCOFs and their corresponding single-crystalline analogues. Upon guest adsorption, HCOF-2 crystals composed of a 3D self-entangled polymer network undergo anisotropic expansion to more than twice their original size, while the 2D-bilayer HCOF-3 crystals exhibit visible, layered sorption bands and form delaminated sheets along the plane of its 2D layers. The dynamic expansion of HCOF networks creates guest-induced porosity with over 473% greater volume than their permanent voids, as calculated from their record-breaking aqueous iodine adsorption capacities. Temperature-gated DMSO sorption investigations illustrated that the flexible nature of cross-linkers in HCOFs provides positive entropy from the coexistence of multiple conformations to allow for elastic expansion and contraction of the frameworks

Use of dispersion modelling for Environmental Impact Assessment of biological air pollution from composting: Progress, problems and prospects

© 2017 The Authors With the increase in composting as a sustainable waste management option, biological air pollution (bioaerosols) from composting facilities have become a cause of increasing concern due to their potential health impacts. Estimating community exposure to bioaerosols is problematic due to limitations in current monitoring methods. Atmospheric dispersion modelling can be used to estimate exposure concentrations, however several issues arise from the lack of appropriate bioaerosol data to use as inputs into models, and the complexity of the emission sources at composting facilities. This paper analyses current progress in using dispersion models for bioaerosols, examines the remaining problems and provides recommendations for future prospects in this area. A key finding is the urgent need for guidance for model users to ensure consistent bioaerosol modelling practices

On the verge of Umdeutung in Minnesota: Van Vleck and the correspondence principle (Part One)

In October 1924, the Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Van Vleck combined advanced techniques of classical mechanics with Bohr's correspondence principle and Einstein's quantum theory of radiation to find quantum analogues of classical expressions for the emission, absorption, and dispersion of radiation. For modern readers Van Vleck's paper is much easier to follow than the famous paper by Kramers and Heisenberg on dispersion theory, which covers similar terrain and is widely credited to have led directly to Heisenberg's "Umdeutung" paper. This makes Van Vleck's paper extremely valuable for the reconstruction of the genesis of matrix mechanics. It also makes it tempting to ask why Van Vleck did not take the next step and develop matrix mechanics himself.Comment: 82 page