Egg-laying substrate selection for optimal camouflage by quail

Camouflage is conferred by background matching and disruption, which are both affected by microhabitat [1]. However, microhabitat selection that enhances camouflage has only been demonstrated in species with discrete phenotypic morphs [2 and 3]. For most animals, phenotypic variation is continuous [4 and 5]; here we explore whether such individuals can select microhabitats to best exploit camouflage. We use substrate selection in a ground-nesting bird (Japanese quail, Coturnix japonica). For such species, threat from visual predators is high [6] and egg appearance shows strong between-female variation [7]. In quail, variation in appearance is particularly obvious in the amount of dark maculation on the light-colored shell [8]. When given a choice, birds consistently selected laying substrates that made visual detection of their egg outline most challenging. However, the strategy for maximizing camouflage varied with the degree of egg maculation. Females laying heavily maculated eggs selected the substrate that more closely matched egg maculation color properties, leading to camouflage through disruptive coloration. For lightly maculated eggs, females chose a substrate that best matched their egg background coloration, suggesting background matching. Our results show that quail “know” their individual egg patterning and seek out a nest position that provides most effective camouflage for their individual phenotyp

A novel profluorescent dinitroxide for imaging polypropylene degradation

Free-radical processes underpin the thermo-oxidative degradation of polyolefins. Thus, to extend the lifetime of these polymers, stabilizers are generally added during processing to scavenge the free radicals formed as the polymer degrades. Nitroxide radical precursors, such as hindered amine stabilizers (HAS),1,2 are common polypropylene additives as the nitroxide moiety is a potent scavenger of polymer alkyl radicals (R¥). Oxidation of HAS by radicals formed during polypropylene degradation yields nitroxide radicals (RRNO¥), which rapidly trap the polymer degradation species to produce alkoxyamines, thus retarding oxidative polymer degradation. This increase in polymer stability is demonstrated by a lengthening of the “induction period” of the polymer (the time prior to a sharp rise in the oxidation of the polymer). Instrumental techniques such as chemiluminescence or infrared spectroscopy are somewhat limited in detecting changes in the polymer during the initial stages of degradation. Therefore, other methods for observing polymer degradation have been sought as the useful life of a polymer does not extend far beyond its “induction period

A study of the UV and VUV degradation of FEP

UV and VUV degradation of fluorinated ethylene propylene (FEP) copolymer was studied using electron spin resonance (ESR) spectroscopy, x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The ESR study revealed the formation of a terminal polymer radical. The stability of this radical was investigated under different environments. An XPS study of FEP film exposed to VUV and atomic oxygen showed that oxidation takes place on the polymer surface. The study revealed also that the percentage of CF2 in the polymer surface decreased with exposure time and the percentage of CF, CF3, and carbon attached to oxygen increased. SEM micrographs of FEP film exposed to VUV and atomic oxygen identified a rough surface with undulations similar to sand dunes

The cAMP-producing agonist beraprost inhibits human vascular smooth muscle cell migration via exchange protein directly activated by cAMP

This work was supported by the British Heart foundation (grant FS/11/23/28730). J.S.M. was funded by a British Heart Foundation PhD studentship. Funding to pay the Open Access publication charges for this article was provided by the Charities Open Access Fund (UK).Peer reviewedPublisher PD

Primary antifungal prophylaxis for cryptococcal disease in HIV‐positive people

Background Cryptococcal disease remains one of the main causes of death in HIV‐positive people who have low cluster of differentiation 4 (CD4) cell counts. Currently, the World Health Organization (WHO) recommends screening HIV‐positive people with low CD4 counts for cryptococcal antigenaemia (CrAg), and treating those who are CrAg‐positive. This Cochrane Review examined the effects of an approach where those with low CD4 counts received regular prophylactic antifungals, such as fluconazole. Objectives To assess the efficacy and safety of antifungal drugs for the primary prevention of cryptococcal disease in adults and children who are HIV‐positive. Search methods We searched the CENTRAL, MEDLINE PubMed, Embase OVID, CINAHL EBSCOHost, WHO International Clinical Trials Registry Platform (WHO ICTRP), ClinicalTrials.gov, conference proceedings for the International AIDS Society (IAS) and Conference on Retroviruses and Opportunistic Infections (CROI), and reference lists of relevant articles up to 31 August 2017. Selection criteria Randomized controlled trials of adults and children, who are HIV‐positive with low CD4 counts, without a current or prior diagnosis of cryptococcal disease that compared any antifungal drug taken as primary prophylaxis to placebo or standard care. Data collection and analysis Two review authors independently assessed eligibility and risk of bias, and extracted and analysed data. The primary outcome was all‐cause mortality. We summarized all outcomes using risk ratios (RR) with 95% confidence intervals (CI). Where appropriate, we pooled data in meta‐analyses. We assessed the certainty of the evidence using the GRADE approach. Main results Nine trials, enrolling 5426 participants, met the inclusion criteria of this review. Six trials administered fluconazole, while three trials administered itraconazole. Antifungal prophylaxis may make little or no difference to all‐cause mortality (RR 1.07, 95% CI 0.80 to 1.43; 6 trials, 3220 participants; low‐certainty evidence). For cryptococcal specific outcomes, prophylaxis probably reduces the risk of developing cryptococcal disease (RR 0.29, 95% CI 0.17 to 0.49; 7 trials, 5000 participants; moderate‐certainty evidence), and probably reduces deaths due to cryptococcal disease (RR 0.29, 95% CI 0.11 to 0.72; 5 trials, 3813 participants; moderate‐certainty evidence). Fluconazole prophylaxis may make no clear difference to the risk of developing clinically resistant Candida disease (RR 0.93, 95% CI 0.56 to 1.56; 3 trials, 1198 participants; low‐certainty evidence); however, there may be an increased detection of fluconazole‐resistant Candida isolates from surveillance cultures (RR 1.25, 95% CI 1.00 to 1.55; 3 trials, 539 participants; low‐certainty evidence). Antifungal prophylaxis was generally well‐tolerated with probably no clear difference in the risk of discontinuation of antifungal prophylaxis compared with placebo (RR 1.01, 95% CI 0.91 to 1.13; 4 trials, 2317 participants; moderate‐certainty evidence). Antifungal prophylaxis may also make no difference to the risk of having any adverse event (RR 1.07, 95% CI 0.88 to 1.30; 4 trials, 2317 participants; low‐certainty evidence), or a serious adverse event (RR 1.08, 95% CI 0.83 to 1.41; 4 trials, 888 participants; low‐certainty evidence) when compared to placebo or standard care. Authors' conclusions Antifungal prophylaxis reduced the risk of developing and dying from cryptococcal disease. Therefore, where CrAG screening is not available, antifungal prophylaxis may be used in patients with low CD4 counts at diagnosis and who are at risk of developing cryptococcal disease

The Abundances Of Neutron-Capture Species In The Very Metal-Poor Globular Cluster M15: A Uniform Analysis Of Red Giant Branch And Red Horizontal Branch Stars

The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and red horizontal branch (RHB) stars. No attempt has been made to perform a single, self-consistent analysis of these stars, which exhibit a wide range in atmospheric parameters. In the current effort, a new comparative abundance derivation is presented for three RGB and six RHB members of the cluster. The analysis employs an updated version of the line transfer code MOOG, which now appropriately treats coherent, isotropic scattering. The apparent discrepancy in the previously reported values for the metallicity of M15 RGB and RHB stars is addressed and a resolute disparity of Delta(RHB-RGB) approximate to 0.1 dex in the iron abundance was found. The anti-correlative behavior of the light neutron-capture elements (Sr, Y, Zr) is clearly demonstrated with both Ba and Eu, standard markers of the s- and r-process, respectively. No conclusive detection of Pb was made in the RGB targets. Consequently for the M15 cluster, this suggests that the main component of the s-process has made a negligible contribution to those elements normally dominated by this process in solar system material. Additionally for the M15 sample, a large Eu abundance spread is confirmed, which is comparable to that of the halo field at the same metallicity. These abundance results are considered in the discussion of the chemical inhomogeneity and nucleosynthetic history of M15.National Science Foundation AST 07-07447, AST 09-08978Astronom

Extending the Functionality of Behavioural Change-Point Analysis with k-Means Clustering: A Case Study with the Little Penguin (Eudyptula minor)

We present a simple framework for classifying mutually exclusive behavioural states within the geospatial lifelines of animals. This method involves use of three sequentially applied statistical procedures: (1) behavioural change point analysis to partition movement trajectories into discrete bouts of same-state behaviours, based on abrupt changes in the spatiotemporal autocorrelation structure of movement parameters; (2) hierarchical multivariate cluster analysis to determine the number of different behavioural states; and (3) k-means clustering to classify inferred bouts of same-state location observations into behavioural modes. We demonstrate application of the method by analysing synthetic trajectories of known ‘artificial behaviours’ comprised of different correlated random walks, as well as real foraging trajectories of little penguins (Eudyptula minor) obtained by global-positioning-system telemetry. Our results show that the modelling procedure correctly classified 92.5% of all individual location observations in the synthetic trajectories, demonstrating reasonable ability to successfully discriminate behavioural modes. Most individual little penguins were found to exhibit three unique behavioural states (resting, commuting/active searching, arearestricted foraging), with variation in the timing and locations of observations apparently related to ambient light, bathymetry, and proximity to coastlines and river mouths. Addition of k-means clustering extends the utility of behavioural change point analysis, by providing a simple means through which the behaviours inferred for the location observations comprising individual movement trajectories can be objectively classified

The surface properties of fluorinated polyimides exposed to VUV and atomic oxygen

The effect of atomic oxygen flux and VUV radiation alone and in combination on the surface of fluorinated polyimide films was studied using XPS spectroscopy. Exposure of fluorinated polyimides to VUV radiation alone caused no observable damage to the polymer surface, while an atomic oxygen flux resulted in substantial oxidation of the surface. On the other hand, exposure to VUV radiation and atomic oxygen in combination caused extensive oxidation of the polymer surface after only 2 minutes of exposure. The amount of oxidized carbon on the polymer surface indicated that there is aromatic ring opening oxidation. The changes in the O1s/C1s, N1s/C1s, and F1s/C1s ratios suggested that an ablative degradation process is highly favorable. A synergistic effect of VUV radiation in the presence of atomic oxygen is clearly evidenced from the XPS study. The atomic oxygen could be considered as the main factor in the degradation process of fluorinated polyimide films exposed to a low earth orbit environment

The effect of simulated low earth orbit radiation on polyimides (UV degradation study)

UV degradation of polyimide films in air and vacuum were studied using UV-visible, ESR, FTIR, and XPS spectroscopies. The UV-visible spectra of polyimide films showed a blue shift in the absorption compared to Kapton. This behavior was attributed to the presence of bulky groups and kinks along the polymer chains which disrupt the formation of a charge transfer complex. The UV-visible spectra showed also that UV irradiation of polyimides result extensively in surface degradation, leaving the bulk of the polymer intact. ESR spectra of polyimides irradiated in vacuum revealed the formation of stable carbon-centered radicals which give a singlet ESR spectrum, while polyimides irradiated in air produced an asymmetric signal shifted to a lower magnetic field, with a higher g value and line width. This signal was attributed to oxygen-cenetered radicals of peroxy and/or alkoxy type. The rate of radical formation in air was two fold higher than for vacuum irradiation, and reached a plateau after a short time. This suggests a continuous depletion of radicals on the surface via an ablative degradation process. FTIR, XPS, and weight loss studies supported this postulate. An XPS study of the surface indicated a substantial increase in the surface oxidation after irradiation in air. The sharp increase in the C-O binding energy peak relative to the C-C peak was believed to be associated with an aromatic ring opening reaction

A candidate fusion engineering material, WC-FeCr

A new candidate fusion engineering material, WC-FeCr, has been irradiated with He ions at 25 and 500 °C. Ions were injected at 6 keV to a dose of ~15 dpa and 50 at. % He, simulating direct helium injection from the plasma. The microstructural evolution was continuously characterised in situ using transmission electron microscopy. In the FeCr phase, a coarse array of 3–6 nm bubbles formed. In the WC, bubbles were less prominent and smaller (~2 nm). Spherical-cap bubbles formed at hetero-phase interfaces of tertiary precipitates, indicating that enhanced processing routes to minimise precipitation could further improve irradiation tolerance