Morphology and biomechanics of the nests of the Common Blackbird Turdus merula

Capsule Common blackbirds select different materials, with varying biomechanical properties, to construct different parts of their nest. Aims This study tested the hypothesis that outer components of a nest have a more structural role and so are stronger than materials used to line the cup. Methods Blackbird nests were measured prior to being dismantled to isolate structural components which were tested for mechanical strength and rigidity. Results Outer nest wall materials were significantly thicker, stronger and more rigid than materials in the inner structural wall or the cup lining. In the vertical plane materials used in the structural wall did not differ. By contrast, lining materials from the bottom of the nest cup were significantly thicker, stronger and more rigid than materials from the top of the cup. Conclusion Blackbirds use different materials in nest construction roles suited to their properties and so may be able to recognise the structural properties of these materials. Materials on the outside of the nest may have a key structural role during construction

Cryptic photosynthesis, Extrasolar planetary oxygen without a surface biological signature

On the Earth, photosynthetic organisms are responsible for the production of virtually all of the oxygen in the atmosphere. On the land, vegetation reflects in the visible, leading to a red edge that developed about 450 Myr ago and has been proposed as a biosignature for life on extrasolar planets. However, in many regions of the Earth, and particularly where surface conditions are extreme, for example in hot and cold deserts, photosynthetic organisms can be driven into and under substrates where light is still sufficient for photosynthesis. These communities exhibit no detectable surface spectral signature to indicate life. The same is true of the assemblages of photosynthetic organisms at more than a few metres depth in water bodies. These communities are widespread and dominate local photosynthetic productivity. We review known cryptic photosynthetic communities and their productivity. We link geomicrobiology with observational astronomy by calculating the disk-averaged spectra of cryptic habitats and identifying detectable features on an exoplanet dominated by such a biota. The hypothetical cryptic photosynthesis worlds discussed here are Earth-analogs that show detectable atmospheric biomarkers like our own planet, but do not exhibit a discernable biological surface feature in the disc-averaged spectrum.Comment: 23 pages, 2 figures, Astrobiology (TBP) - updated Table 1, typo in detectable O2 correcte

The effect of incentive spirometry on postoperative pulmonary function following laparotomy a randomized clinical trial

Importance: Changes in pulmonary dynamics following laparotomy are well documented. Deep breathing exercises, with or without incentive spirometry, may help counteract postoperative decreased vital capacity; however, the evidence for the role of incentive spirometry in the prevention of postoperative atelectasis is inconclusive. Furthermore, data are scarce regarding the prevention of postoperative atelectasis in sub-Saharan Africa. Objective: To determine the effect of the use of incentive spirometry on pulmonary function following exploratory laparotomy as measured by forced vital capacity (FVC). Design, Setting, and Participants: Thiswas a single-center, randomized clinical trial performed at Kamuzu Central Hospital, Lilongwe, Malawi. Study participants were adult patients who underwent exploratory laparotomy and were randomized into the intervention or control groups (standard of care) from February 1 to November 30, 2013. All patients received routine postoperative care, including instructions for deep breathing and early ambulation.We used bivariate analysis to compare outcomes between the intervention and control groups. Intervention: Adult patients who underwent exploratory laparotomy participated in postoperative deep breathing exercises. Patients in the intervention group received incentive spirometers Main outcomes and measures: We assessed pulmonary function using a peak flow meter to measure FVC in both groups of patients. Secondary outcomes, such as hospital length of stay and mortality, were obtained from the medical records. Results: A total of 150 patients were randomized (75 in each arm). The median age in the intervention and control groups was 35 years (interquartile range, 28-53 years) and 33 years (interquartile range, 23-46 years), respectively. Men predominated in both groups, and most patients underwent emergency procedures (78.7%in the intervention group and 84.0%in the control group). Mean initial FVC did not differ significantly between the intervention and control groups (0.92 and 0.90 L, respectively; P = .82 [95%CI, 0.52-2.29]). Although patients in the intervention group tended to have higher final FVC measurements, the change between the first and last measured FVC was not statistically significant (0.29 and 0.25 L, respectively; P = .68 [95%CI, 0.65-1.95]). Likewise, hospital length of stay did not differ significantly between groups. Overall postoperative mortality was 6.0%, with a higher mortality rate in the control group compared with the intervention group (10.7%and 1.3%, respectively; P = .02 [95%CI, 0.01-0.92]). Conclusions and Relevance: Education and provision of incentive spirometry for unmonitored patient use does not result in statistically significant improvement in pulmonary dynamics following laparotomy.We would not recommend the addition of incentive spirometry to the current standard of care in this resource-constrained environment. Trial registration: clinicaltrials.gov Identifier: NCT01789177

The effect of seasonality on burn incidence, severity and outcome in Central Malawi

Introduction In much of the world, burns are more common in cold months. However, few studies have described the seasonality of burns in sub-Saharan Africa. This study examines the effect of seasonality on the incidence and outcome of burns in central Malawi. Methods A retrospective analysis was performed at Kamuzu Central Hospital and included all patients admitted from May 2011 to August 2014. Demographic data, burn mechanism, total body surface area (%TBSA), and mortality were analyzed. Seasons were categorized as Rainy (December–February), Lush (March–May), Cold (June–August) and Hot (September–November). A negative binomial regression was used to assess the effect of seasonality on burn incidence. This was performed using both the raw and deseasonalized data in order to evaluate for trends not attributable to random fluctuation. Results A total of 905 patients were included. Flame (38%) and Scald (59%) burns were the most common mechanism. More burns occurred during the cold season (41% vs 19–20% in the other seasons). Overall mortality was 19%. Only the cold season had a statistically significant increase in burn. The incidence rate ratios (IRR) for the hot, lush, and cold seasons were 0.94 (CI 0.6–1.32), 1.02 (CI 0.72–1.45) and 1.6 (CI 1.17–2.19), respectively, when compared to the rainy season. Burn severity and mortality did not differ between seasons. Conclusion The results of this study demonstrate the year-round phenomenon of burns treated at our institution, and highlights the slight predominance of burns during the cold season. These data can be used to guide prevention strategies, with special attention to the implications of the increased burn incidence during the cold season. Though burn severity and mortality remain relatively unchanged between seasons, recognizing the seasonal variability in incidence of burns is critical for resource allocation in this low-income setting

Collinear effective theory at subleading order and its application to heavy-light currents

We consider a collinear effective theory of highly energetic quarks with energy E, interacting with collinear and soft gluons by integrating out collinear degrees of freedom to subleading order. The collinear effective theory offers a systematic expansion in power series of a small parameter lambda ~ p_{\perp}/E, where p_{\perp} is the transverse momentum of a collinear particle. We construct the effective Lagrangian to first order in $\lambda$, and discuss its features including additional symmetries such as collinear gauge invariance and reparameterization invariance. Heavy-light currents can be matched from the full theory onto the operators in the collinear effective theory at one loop and to order lambda. We obtain heavy-light current operators in the effective theory, calculate their Wilson coefficients at this order, and the renormalization group equations for the Wilson coefficients are solved. As an application, we calculate the form factors for decays of B mesons to light energetic mesons to order lambda and at leading-logarithmic order in alpha_s.Comment: 29 pages, 5 figures, revised versio

B-->pi and B-->K transitions in standard and quenched chiral perturbation theory

We study the effects of chiral logs on the heavy-->light pseudoscalar meson transition form factors by using standard and quenched chiral perturbation theory combined with the static heavy quark limit. The resulting expressions are used to indicate the size of uncertainties due to the use of the quenched approximation in the current lattice studies. They may also be used to assess the size of systematic uncertainties induced by missing chiral log terms in extrapolating toward the physical pion mass. We also provide the coefficient multiplying the quenched chiral log, which may be useful if the quenched lattice studies are performed with very light mesons.Comment: 33 pages, 8 PostScript figures, version to appear in PR

First-egg date and air temperature affect nest construction in Blue Tits Cyanistes caeruleus, but not in Great Tits Parus major

Capsule For nest construction by Blue Tits, but not Great Tits, first-egg date (FED) and air temperature significantly affected the mass of the nest as a whole and some of its component parts. Aims To test the hypothesis that use of nest materials is influenced by prevailing climatic conditions during nest construction. Methods Nests used in the study were built by Blue Tits Cyanistes caeruleus and Great Tits Parus major in nestboxes at a site in Lincolnshire, England during the 2008 and 2009 breeding seasons. Nests were dissected into their component parts and then weighed. Results Stepwise discriminant analysis showed that the asses of grasses, feathers and bark were significantly affected by species (all higher in Blue Tits) and year significantly affected the mass of wool and dust in the nests. ANOVA showed that total mass of the nest was not significantly affected by year of construction or species. By contrast, species, but not year, did significantly influence the masses of animal- and plant-derived materials in the nest. In Blue Tit nests there were significant correlations between FED and the mass of animal-derived material in 2008, but with plant-derived material in 2009. There were significant correlations between mean air temperature recorded during the seven days up to FED and the mass of the nests and their plant-derived materials. No significant correlations were observed between FED and nest components for Great Tits. Conclusion Nest construction is potentially affected by a variety of environmental factors, which may impact upon how nests function. A better understanding of how nest variability affects its function may allow better assessment of how climate change may impact upon the reproductive performance of bird

Unfamiliar Territory: Emerging Themes for Ecological Drought Research and Management

Novel forms of drought are emerging globally, due to climate change, shifting teleconnection patterns, expanding human water use, and a history of human influence on the environment that increases the probability of transformational ecological impacts. These costly ecological impacts cascade to human communities, and understanding this changing drought landscape is one of today\u27s grand challenges. By using a modified horizon-scanning approach that integrated scientists, managers, and decision-makers, we identified the emerging issues in ecological drought that represent key challenges to timely and effective responses. Here we review the themes that most urgently need attention, including novel drought conditions, the potential for transformational drought impacts, and the need for anticipatory drought management. This horizon scan and review provides a roadmap to facilitate the research and management innovations that will support forward-looking, co-developed approaches to reduce the risk of drought to our socio-ecological systems during the 21st century. We used a modified horizon-scanning approach that brought together scientists, managers, and decision-makers to identify the emerging issues around the ecological impacts from drought that represent key challenges to effective response. We found three broad themes within ecological drought that need attention, including novel drought conditions, transformational drought impacts, and anticipatory drought management. This horizon scan and integrated review provides a roadmap to inspire the needed research and management innovations to reduce the risk of 21st century droughts

Phenomenology of non-standard Z couplings in exclusive semileptonic b -> s transitions

The rare decays $B\to K^{(*)}\ell^+\ell^-$, $B\to K^{(*)}\nu\bar\nu$ and $B_s\to\mu^+\mu^-$ are analyzed in a generic scenario where New Physics effects enter predominantly via $Z$ penguin contributions. We show that this possibility is well motivated on theoretical grounds, as the $\bar sbZ$ vertex is particularly susceptible to non-standard dynamics. In addition, such a framework is also interesting phenomenologically since the $\bar sbZ$ coupling is rather poorly constrained by present data. The characteristic features of this scenario for the relevant decay rates and distributions are investigated. We emphasize that both sign and magnitude of the forward-backward asymmetry of the decay leptons in $\bar B\to \bar K^*\ell^+\ell^-$, ${\cal A}^{(\bar B)}_{FB}$, carry sensitive information on New Physics. The observable ${\cal A}^{(\bar B)}_{FB}+{\cal A}^{(B)}_{FB}$ is proposed as a useful probe of non-standard CP violation in $\bar sbZ$ couplings.Comment: Minor modifications; version to appear in Phys. Rev.