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Sympatric ocelots (Leopardus pardalis) and bobcats (Lynx rufus) in South Texas show substantial overlap in body size, food habits, and habitat use. Consequently, we explore whether temporal niche partitioning may explain ocelot and bobcat coexistence. We investigated the influence of sun angle, lunar illumination, and maximum diurnal temperature on temporal movement rates of sympatric ocelots (n = 8) and bobcats (n = 6) using a combination of high-frequency GPS locations and bi-axial accelerometer data. We demonstrated that accelerometer data could be used to predict movement rates, providing a nearly continuous measure of animal activity and supplementing GPS locations. Ocelots showed a strong nocturnal activity pattern with the highest movement rates at night whereas bobcats showed a crepuscular activity pattern with the highest movement rates occurring around sunrise and sunset. Although bobcat activity levels were lower during the day, bobcat diurnal activity was higher than ocelot diurnal activity. During warmer months, bobcats were more active on nights with high levels of lunar illumination. In contrast, ocelots showed the highest nocturnal activity levels during periods of low lunar illumination. Ocelots showed reduced diurnal activity on hotter days. Our results indicate that ocelot and bobcat coexistence in South Texas can be partially explained by temporal niche partitioning, although both felids showed periods of overlapping activity during nocturnal and crepuscular periods.

We characterize the variation in photometric response of the Dark Energy Camera (DECam) across its 520 Mpix science array during 4 years of operation. These variations are measured using high signal-to-noise aperture photometry of >107 stellar images in thousands of exposures of a few selected fields, with the telescope dithered to move the sources around the array. A calibration procedure based on these results brings the rms variation in aperture magnitudes of bright stars on cloudless nights down to 2-3 mmag, with <1 mmag of correlated photometric errors for stars separated by ≥20″. On cloudless nights, any departures of the exposure zeropoints from a secant airmass law exceeding 1 mmag are plausibly attributable to spatial/temporal variations in aperture corrections. These variations can be inferred and corrected by measuring the fraction of stellar light in an annulus between 6″ and 8″ diameter. Key elements of this calibration include: correction of amplifier nonlinearities; distinguishing pixel-area variations and stray light from quantum-efficiency variations in the flat fields; field-dependent color corrections; and the use of an aperture-correction proxy. The DECam response pattern across the 2° field drifts over months by up to 9 mmag, in a nearly wavelength-independent low-order pattern. We find no fundamental barriers to pushing global photometric calibrations toward mmag accuracy.

Heightened concern over endocrine-disrupting chemicals is driven by the hypothesis that they could reduce reproductive success and affect wildlife populations, but there is little evidence for this expectation. The pharmaceutical ethynylestradiol ( EE2) is a potent endocrine modulator and is present in the aquatic environment at biologically active concentrations. To investigate impacts on reproductive success and mechanisms of disruption, we exposed breeding populations (n = 12) of zebrafish (Danio rerio) over multiple generations to environmentally relevant concentrations of EE2. Life-long exposure to 5 ng/ L EE2in the F1generation caused a 56% reduction in fecundity and complete population failure with no fertilization. Conversely, the same level of exposure for up to 40 days in mature adults in the parental F0generation had no impact on reproductive success. Infertility in the F1generation after life-long exposure to 5 ng/ L EE2was due to disturbed sexual differentiation, with males having no functional testes and either undifferentiated or intersex gonads. These F1males also showed a reduced vitellogenic response when compared with F0males, indicating an acclimation to EE2exposure. Depuration studies found only a partial recovery in reproductive capacity after 5 months. Significantly, even though the F1males lacked functional testes, they showed male-pattern reproductive behavior, inducing the spawning act and competing with healthy males to disrupt fertilization. Endocrine disruption is therefore likely to affect breeding dynamics and reproductive success in group-spawning fish. Our findings raise major concerns about the population-level impacts for wildlife of long-term exposure to low concentrations of estrogenic endocrine disruptors.

We describe the model for mapping from sky brightness to the digital output of the Dark Energy Camera (DECam) and the algorithms adopted by the Dark Energy Survey (DES) for inverting this model to obtain photometric measures of celestial objects from the raw camera output. This calibration aims for fluxes that are uniform across the camera field of view and across the full angular and temporal span of the DES observations, approaching the accuracy limits set by shot noise for the full dynamic range of DES observations. The DES pipeline incorporates several substantive advances over standard detrending techniques, including principal-components-based sky and fringe subtraction; correction of the \"brighter-fatter\" nonlinearity; use of internal consistency in on-sky observations to disentangle the influences of quantum efficiency, pixel-size variations, and scattered light in the dome flats; and pixel-by-pixel characterization of instrument spectral response, through combination of internal-consistency constraints with auxiliary calibration data. This article provides conceptual derivations of the detrending/calibration steps, and the procedures for obtaining the necessary calibration data. Other publications will describe the implementation of these concepts for the DES operational pipeline, the detailed methods, and the validation that the techniques can bring DECam photometry and astrometry within 2 mmag and 3 mas, respectively, of fundamental atmospheric and statistical limits. The DES techniques should be broadly applicable to wide-field imagers.

A partial life‐cycle assay (PLC) with zebrafish (Danio rerio) was conducted to identify endocrine‐disrupting effects of 17β‐estradiol (E2) and tamoxifen (TMX) as reference for estrogen agonist and antagonist activity. Adult zebrafish were exposed for 21 d and offspring for another 42 d, allowing differentiation of gonads in control animals. The assessed end points included reproductive variables (egg production, fertilization, and hatching), gonad differentiation of juveniles, histopathology, and vitellogenin (VTG) expression. With E2, the most sensitive end points were feminization of offspring (at 0.1 nM) and increased VTG production in males (at 0.32 nM). At 1 nM, decreased F1 survival, increased F1 body length and weight, VTG‐related edema and kidney lesions, and inhibited spermatogenesis were observed. Oocyte atresia occurred at even higher concentrations. Exposure to TMX resulted in specific effects at an intermediate test concentration (87 nM), including oocyte atresia with granulosa cell transformation and disturbed spermatogenesis (asynchrony within cysts). In F1, decreased hatching, survival, and body weight and length as well as decreased feminization were observed. Decreased vitellogenesis and egg production in females and clustering of Leydig cells in males occurred at higher concentrations. Toxicological profiles of estrogen agonists and antagonists are complex and specific; a valid and refined characterization of endocrine activity of field samples therefore can be obtained only by using a varied set of end points, including histology, as applied in the presented PLC. Evaluation of only a single end point can easily produce under‐ or overestimation of the actual hazard.

Toxicological effects of the widely used flame retardant, tetrabromobisphenol A (TBBPA) were assessed in a partial life-cycle test with zebrafish (Danio rerio). Exposure of adult fish during 30 days to water-borne TBBPA in nominal concentrations ranging from 0 (control) to 1.5 microM was followed by exposure of the offspring in early life stages up to 47 days posthatching (dph) to the same concentrations. Adults exposed to 3 and 6 microM showed severe disorientation and lethargy shortly after beginning of exposure and were euthanized. Because semistatic exposure resulted in fluctuating water concentrations, pooled fish samples were chemically analyzed for internal dose assessment. Egg production was decreased in fish exposed to TBBPA concentrations of 0.047 microM and higher, and a critical effect level of 7.2 microg/g lipid with a lower 5% confidence limit of 3.9 microg/g lipid for 50% decreased egg production was calculated. Histology of adult ovaries indicated a relative increase of premature oocytes in two surviving females exposed to 1.5 microM. Hatching of TBBPA-exposed larvae was decreased except in animals exposed to 0.375 microM. In the highest exposure concentration, early posthatching mortality was high (81%) in larvae and the surviving juveniles showed a significant predominance of the female phenotype. Exposure of eggs from control parents up to 6 microM TBBPA resulted in increasing malformation and pericardial fluid accumulation from 1.5 microM; at higher concentrations, all embryos failed to hatch. The presented results indicate decreased reproductive success in zebrafish at environmentally relevant TBBPA concentrations.

XERODERM A pigmentosum patients with a defect in the nucleotide-excision repair gene XPA are characterized by, for example, a > 1,000-fold higher risk of developing sunlight-induced skin cancer 1–3 . Nucleo tide-excision repair (NER) is involved in the removal of a wide spectrum of DNA lesions. The XPA protein functions in a pre-incision step, the recognition of DNA damage 4–7 . To permit the functional analysis of the XPA gene in vivo, we have generated XPA -deficient mice by gene targeting in embryonic stem cells. The XPA −f− mice appear normal, at least until the age of 13 months. XPA−1− mice are highly susceptible to ultraviolet (UV)-B-induced skin and eye tumours and to 7,12-dimethylbenz-[a]anthracene (DMBA)-induced skin tumours. We conclude that the XPA -deficient mice strongly mimic the phenotype of humans with xeroderma pigmentosum.

In industrialized countries, it is recommended that adults with human immunodeficiency virus type 1 (HIV-1) infection undergo baseline screening for pathogens that might cause latent or active infections, such as syphilis, hepatitis B, hepatitis C, infection due to Toxoplasma gondii, and cytomegalovirus infection. A paucity of data exist from sub-Saharan Africa describing the prevalence of these pathogens. We report data for HIV-1–infected adults referred for initiation of highly active antiretroviral therapy in Botswana.

The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a ∼5000 deg2 survey of the southern sky in five optical bands (g, r, i, z, Y) to a depth of ∼24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g, r, i, z) over ∼27 deg2. DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also performed in the time domain component nightly. On a bi-annual basis, DES exposures are reprocessed with a refined pipeline and coadded to maximize imaging depth. Here we describe the DES image processing pipeline in support of DES science, as a reference for users of archival DES data, and as a guide for future astronomical surveys.

Xeroderma pigmentosum (XP) patients with a defect in the nucleotide excision repair gene XPA, develop tumors with a high frequency on sun-exposed areas of the skin. Here we describe that hairless XPA-deficient mice also develop skin tumors with a short latency time and a 100% prevalence after daily exposure to low doses of U.V.B. Surprisingly and in contrast to U.V.B.-exposed repair proficient hairless mice who mainly develop squamous cell carcinomas, the XPA-deficient mice developed papillomas with a high frequency (31%) at a U.V. dose of 32 J/m2 daily. At the highest daily dose of 80 J/m2 mainly squamous cell carcinomas (56%) and only 10% of papillomas were found in XPA-deficient hairless mice. p53 gene mutations were examined in exons 5, 7 and 8 and were detected in only 3 out of 37 of these skin tumors, whereas in tumors of control U.V.B.-irradiated wild type littermates this frequency was higher (45%) and more in line with our previous data. Strikingly, a high incidence of activating ras gene mutations were observed in U.V.B.-induced papillomas (in 11 out of 14 tumors analysed). In only two out of 14 squamous cell carcinomas we found similar ras gene mutations. The observed shift from squamous cell carcinomas in wild type hairless mice to papillomas in XPA-deficient hairless mice, and a corresponding shift in mutated cancer genes in these tumors, provide new clues on the pathogenesis of chemically- versus U.V.B.-induced skin carcinogenesis.