3,567 research outputs found

    Testing the strength and direction of selection on vocal frequency using metabolic scaling theory

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    A major challenge for studies assessing drivers of phenotypic divergence is the statistical comparison of taxa with unique, often unknown, evolutionary histories, and for which there are no clear expected trait values. Because many traits are fundamentally constrained by energy availability, we suggest that trait values predicted by scaling theories such as the metabolic theory of ecology (MTE) can provide baseline expectations. Here, we introduce a metabolic scaling-based approach to test theory involving the direction and magnitude of ecological and sexual selection, using vocal frequency as an example target of selection. First, we demonstrate that MTE predicts the relationship between the natural log of body size and natural log of vocal frequency across 795 bird species, controlling for phylogeny. Family-wide deviations in slope and intercepts from MTE estimates reveal taxa with potentially important differences in physiology or natural history. Further, species-level frequency deviations from MTE expectations are predicted by factors related to ecological and sexual selection and, in some cases, provide evidence that differs from current understanding of the direction of selection and identity of ecological selective agents. For example, our approach lends additional support to the findings from many cross-habitat studies that suggest that dense vegetation selects for lower frequency signals. However, our analysis also suggests that birds in non-forested environments vocalize at frequencies higher than expected based on MTE, prompting intriguing questions about the selective forces in non-forest environments that may act on vocal frequency. Additionally, vocal frequency deviates more strongly from MTE expectations among species with smaller repertoires and those with low levels of sexual dichromatism, complicating the use of these common sexual selection surrogates. Broad application of our metabolic scaling approach might provide an important complementary approach to understanding how selection shapes phenotypic evolution by offering a common baseline across studies and taxa and providing the basis to explore evolutionary trade-offs within and among multicomponent and multimodal traits

    External iliac artery dissection secondary to endofibrosis in a cyclist

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    Endofibrosis of the external iliac artery is an uncommon disease affecting primarily young, otherwise healthy, endurance athletes. Thigh pain during maximal exercise with quick resolution postexercise is characteristic of the so-called cyclist's iliac syndrome. We report an unusual case in which the typical endofibrotic plaque was accompanied by dissection of the external iliac artery. The patient was treated surgically with excision of the affected artery segment and placement of an interposition graft. This case highlights an unusual finding in association with external iliac artery endofibrosis and provides an opportunity to briefly review the literature on the subject

    Ex vivo gene therapy using intravitreal injection of GDNF-secreting mouse embryonic stem cells in a rat model of retinal degeneration

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    Purpose: Safe and prolonged drug delivery to the retina is a key obstacle to overcome in the development of new medicines aimed at treating progressive retinal disease. We took advantage of the ability of embryonic stem cells to survive long-term in foreign tissue and used these cells to deliver neuroprotectant molecules to the retina of the rhodopsin TgN S334ter-4 rat model of retinitis pigmentosa (RP). Methods: Mouse embryonic stem (mES) cells, derived from the pluripotent embryonic stem cell line E14TG2a, were genetically engineered to oversecrete the glial cell-derived neurotrophic factor (GDNF). Cell suspensions, containing approximately 200,000 cells and expressing approximately 35ng/106 cells/24 h GDNF, were injected into the vitreous cavity of TgN S334ter rat eyes at postnatal day 21 (P21) without immunosuppression. Histological and immunofluorescence imaging was used to evaluate photoreceptor survival up to P90. Local (vitreous) and systemic (serum) concentrations of GDNF were determined and ocular side effects were monitored. Results: Green fluorescent protein (GFP)-expressing mES cells were observed on the inner limiting membrane of the retina in retinal flatmounts up to P90. In cryostat sections at P45, some GFP-expressing cells had integrated into the inner retina, but did not migrate into the outer nuclear layer. After an initial lag period, the photoreceptor cell counts were significantly higher (p≤0.05) in animals treated with GDNF-secreting mES cells than in untreated animals, principally in the peripheral retina. Several adverse side effects such as tractional detachments and areas of hyperplasia were seen in a minimal number of treated eyes. Abnormally high levels of GDNF in the peripheral circulation were also observed. Conclusions: ES cells engineered to secrete GDNF exerted a neuroprotective effect for at least three months on retinal structure in the TgN S334ter rat model of retinal degeneration. Immunosuppression was not required for this. Several adverse effects were identified which require further investigation to make cell-based delivery of neuroprotection a viable clinical strategy

    The Transit Light Curve Project. VI. Three Transits of the Exoplanet TrES-2

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    Of the nearby transiting exoplanets that are amenable to detailed study, TrES-2 is both the most massive and has the largest impact parameter. We present z-band photometry of three transits of TrES-2. We improve upon the estimates of the planetary, stellar, and orbital parameters, in conjunction with the spectroscopic analysis of the host star by Sozzetti and co-workers. We find the planetary radius to be 1.222 +/- 0.038 R_Jup and the stellar radius to be 1.003 +/- 0.027 R_Sun. The quoted uncertainties include the systematic error due to the uncertainty in the stellar mass (0.980 +/- 0.062 M_Sun). The timings of the transits have an accuracy of 25s and are consistent with a uniform period, thus providing a baseline for future observations with the NASA Kepler satellite, whose field of view will include TrES-2.Comment: 15 pages, including 2 figures, accepted Ap

    Self-Affirmation Activates Brain Systems Associated with Self-Related Processing and Reward and is Reinforced by Future Orientation

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    Self-affirmation theory posits that people are motivated to maintain a positive self-view and that threats to perceived self-competence are met with resistance. When threatened, self-affirmations can restore self-competence by allowing individuals to reflect on sources of self-worth, such as core values. Many questions exist, however, about the underlying mechanisms associated with self-affirmation. We examined the neural mechanisms of self-affirmation with a task developed for use in a functional magnetic resonance imaging environment. Results of a region of interest analysis demonstrated that participants who were affirmed (compared with unaffirmed participants) showed increased activity in key regions of the brain’s self-processing (medial prefrontal cortex + posterior cingulate cortex) and valuation (ventral striatum + ventral medial prefrontal cortex) systems when reflecting on future-oriented core values (compared with everyday activities). Furthermore, this neural activity went on to predict changes in sedentary behavior consistent with successful affirmation in response to a separate physical activity intervention. These results highlight neural processes associated with successful self-affirmation, and further suggest that key pathways may be amplified in conjunction with prospection

    Oligonucleotide array discovery of polymorphisms in cultivated tomato (Solanum lycopersicum L.) reveals patterns of SNP variation associated with breeding

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    Background: Cultivated tomato (Solanum lycopersicum L.) has narrow genetic diversity that makes it difficult to identify polymorphisms between elite germplasm. We explored array-based single feature polymorphism (SFP) discovery as a high-throughput approach for marker development in cultivated tomato. Results: Three varieties, FL7600 (fresh-market), OH9242 (processing), and PI114490 (cherry) were used as a source of genomic DNA for hybridization to oligonucleotide arrays. Identification of SFPs was based on outlier detection using regression analysis of normalized hybridization data within a probe set for each gene. A subset of 189 putative SFPs was sequenced for validation. The rate of validation depended on the desired level of significance (α) used to define the confidence interval (CI), and ranged from 76% for polymorphisms identified at α ≤ 10-6 to 60% for those identified at α ≤ 10-2. Validation percentage reached a plateau between α ≤ 10-4 and α ≤ 10-7, but failure to identify known SFPs (Type II error) increased dramatically at α ≤ 10-6. Trough sequence validation, we identified 279 SNPs and 27 InDels in 111 loci. Sixty loci contained ≥ 2 SNPs per locus. We used a subset of validated SNPs for genetic diversity analysis of 92 tomato varieties and accessions. Pairwise estimation of θ (Fst) suggested significant differentiation between collections of fresh-market, processing, vintage, Latin American (landrace), and S. pimpinellifolium accessions. The fresh-market and processing groups displayed high genetic diversity relative to vintage and landrace groups. Furthermore, the patterns of SNP variation indicated that domestication and early breeding practices have led to progressive genetic bottlenecks while modern breeding practices have reintroduced genetic variation into the crop from wild species. Finally, we examined the ratio of non-synonymous (Ka) to synonymous substitutions (Ks) for 20 loci with multiple SNPs (≥ 4 per locus). Six of 20 loci showed ratios of Ka/Ks ≥ 0.9. Conclusion: Array-based SFP discovery was an efficient method to identify a large number of molecular markers for genetics and breeding in elite tomato germplasm. Patterns of sequence variation across five major tomato groups provided insight into to the effect of human selection on genetic variation

    Pain Coping Skills Training for Patients Who Catastrophize About Pain Prior to Knee Arthroplasty: A Multisite Randomized Clinical Trial

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    BACKGROUND: Pain catastrophizing has been identified as a prognostic indicator of poor outcome following knee arthroplasty. Interventions to address pain catastrophizing, to our knowledge, have not been tested in patients undergoing knee arthroplasty. The purpose of this study was to determine whether pain coping skills training in persons with moderate to high pain catastrophizing undergoing knee arthroplasty improves outcomes 12 months postoperatively compared with usual care or arthritis education. METHODS: A multicenter, 3-arm, single-blinded, randomized comparative effectiveness trial was performed involving 5 university-based medical centers in the United States. There were 402 randomized participants. The primary outcome was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain Scale, measured at baseline, 2 months, 6 months, and 12 months following the surgical procedure. RESULTS: Participants were recruited from January 2013 to June 2016. In 402 participants, 66% were women and the mean age of the participants (and standard deviation) was 63.2 ± 8.0 years. Three hundred and forty-six participants (90% of those who underwent a surgical procedure) completed a 12-month follow-up. All 3 treatment groups had large improvements in 12-month WOMAC pain scores with no significant differences (p > 0.05) among the 3 treatment arms. No differences were found between WOMAC pain scores at 12 months for the pain coping skills and arthritis education groups (adjusted mean difference, 0.3 [95% confidence interval (CI), -0.9 to 1.5]) or between the pain coping and usual-care groups (adjusted mean difference, 0.4 [95% CI, -0.7 to 1.5]). Secondary outcomes also showed no significant differences (p > 0.05) among the 3 groups. CONCLUSIONS: Among adults with pain catastrophizing undergoing knee arthroplasty, cognitive behaviorally based pain coping skills training did not confer pain or functional benefit beyond the large improvements achieved with usual surgical and postoperative care. Future research should develop interventions for the approximately 20% of patients undergoing knee arthroplasty who experience persistent function-limiting pain. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence

    The Southern 2MASS AGN Survey: spectroscopic follow-up with 6dF

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    The Two Micron All-Sky Survey (2MASS) has provided a uniform photometric catalog to search for previously unknown red AGN and QSOs. We have extended the search to the southern equatorial sky by obtaining spectra for 1182 AGN candidates using the 6dF multifibre spectrograph on the UK Schmidt Telescope. These were scheduled as auxiliary targets for the 6dF Galaxy Redshift Survey. The candidates were selected using a single color cut of J - Ks > 2 to Ks ~ 15.5 and a galactic latitude of |b|>30 deg. 432 spectra were of sufficient quality to enable a reliable classification. 116 sources (or ~27%) were securely classified as type 1 AGN, 20 as probable type 1s, and 57 as probable type 2 AGN. Most of them span the redshift range 0.05<z<0.5 and only 8 (or ~6%) were previously identified as AGN or QSOs. Our selection leads to a significantly higher AGN identification rate amongst local galaxies (>20%) than in any previous galaxy survey. A small fraction of the type 1 AGN could have their optical colors reddened by optically thin dust with A_V<2 mag relative to optically selected QSOs. A handful show evidence for excess far-IR emission. The equivalent width (EW) and color distributions of the type 1 and 2 AGN are consistent with AGN unified models. In particular, the EW of the [OIII] emission line weakly correlates with optical--near-IR color in each class of AGN, suggesting anisotropic obscuration of the AGN continuum. Overall, the optical properties of the 2MASS red AGN are not dramatically different from those of optically-selected QSOs. Our near-IR selection appears to detect the most near-IR luminous QSOs in the local universe to z~0.6 and provides incentive to extend the search to deeper near-IR surveys.Comment: 57 pages, 12 figures, 4 tables, to appear in vol.27/4 of Publications of the Astronomical Society of Australia (PASA

    New insight into the molecular control of bacterial functional amyloids.

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    New insight into the molecular control of bacterial functional amyloids. Front. Cell. Infect. Microbiol. 5:33. doi: 10.3389/fcimb.2015.00033 New insight into the molecular control of bacterial functional amyloid
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