118 research outputs found

    Evo-devo of human adolescence: beyond disease models of early puberty

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    Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research

    Isolated and dynamical horizons and their applications

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    Over the past three decades, black holes have played an important role in quantum gravity, mathematical physics, numerical relativity and gravitational wave phenomenology. However, conceptual settings and mathematical models used to discuss them have varied considerably from one area to another. Over the last five years a new, quasi-local framework was introduced to analyze diverse facets of black holes in a unified manner. In this framework, evolving black holes are modeled by dynamical horizons and black holes in equilibrium by isolated horizons. We review basic properties of these horizons and summarize applications to mathematical physics, numerical relativity and quantum gravity. This paradigm has led to significant generalizations of several results in black hole physics. Specifically, it has introduced a more physical setting for black hole thermodynamics and for black hole entropy calculations in quantum gravity; suggested a phenomenological model for hairy black holes; provided novel techniques to extract physics from numerical simulations; and led to new laws governing the dynamics of black holes in exact general relativity.Comment: 77 pages, 12 figures. Typos and references correcte

    Twenty-four hours secretion pattern of serum estradiol in healthy prepubertal and pubertal boys as determined by a validated ultra-sensitive extraction RIA

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    <p>Abstract</p> <p>Background</p> <p>The role of estrogens in male physiology has become evident. However, clinically useful normative data for estradiol secretion in boys has not previously been established due to the insensitivity of current methods used in clinical routine. By use of a validated ultra-sensitive extraction RIA, our aim was to establish normative data from a group consisting of healthy boys in prepuberty and during pubertal development.</p> <p>Methods</p> <p>Sixty-two 24-hours serum profiles (6 samples/24 hours) were obtained from 44 healthy boys (ages; 7.2–18.6 years) during their pubertal development, classified into five stages: prepuberty (testis, 1–2 mL), early (testis, 3–6 mL), mid (testis, 8–12 mL), late-1 (testis,15–25 mL, not reached final height) and late-2 (testis,15–25 mL, reached final height). Serum estradiol was determined by an ultra- sensitive extraction radioimmunoassay with detection limit 4 pmol/L and functional sensitivity 6 pmol/L.</p> <p>Results</p> <p>Mean estradiol concentrations during 24-hours secretion increased from prepuberty (median: <4 (5–95 percentiles: <4 – 7) pmol/L) to early puberty (6 (<4 – 12 pmol/L) but then remained relatively constant until a marked increase between mid-puberty (8 (4 – 17) pmol/L) and late-1 (21 (12 – 37) pmol/L) puberty, followed by a slower increase until late-2 puberty (32 (20 – 47) pmol/L). The diurnal rhythm of serum estradiol was non-measurable in pre- and early puberty, but discerned in mid-puberty, and become evident in late pubertal stages with peak values at 0600 to 1000 h.</p> <p>Conclusion</p> <p>With the use of an ultra-sensitive extraction RIA, we have provided clinically useful normative data for estradiol secretion in boys.</p

    Small intestinal microbial dysbiosis underlies symptoms associated with functional gastrointestinal disorders

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    Small intestinal bacterial overgrowth (SIBO) has been implicated in symptoms associated with functional gastrointestinal disorders (FGIDs), though mechanisms remain poorly defined and treatment involves non-specific antibiotics. Here we show that SIBO based on duodenal aspirate culture reflects an overgrowth of anaerobes, does not correspond with patient symptoms, and may be a result of dietary preferences. Small intestinal microbial composition, on the other hand, is significantly altered in symptomatic patients and does not correspond with aspirate culture results. In a pilot interventional study we found that switching from a high fiber diet to a low fiber, high simple sugar diet triggered FGID-related symptoms and decreased small intestinal microbial diversity while increasing small intestinal permeability. Our findings demonstrate that characterizing small intestinal microbiomes in patients with gastrointestinal symptoms may allow a more targeted antibacterial or a diet-based approach to treatment

    Rotating Stars in Relativity

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    Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information one could obtain about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.Comment: 101 pages, 18 figures. The full online-readable version of this article, including several animations, will be published in Living Reviews in Relativity at http://www.livingreviews.org

    Exploring new physics frontiers through numerical relativity

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    The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

    Gravitational Wave Detection by Interferometry (Ground and Space)

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    Significant progress has been made in recent years on the development of gravitational wave detectors. Sources such as coalescing compact binary systems, neutron stars in low-mass X-ray binaries, stellar collapses and pulsars are all possible candidates for detection. The most promising design of gravitational wave detector uses test masses a long distance apart and freely suspended as pendulums on Earth or in drag-free craft in space. The main theme of this review is a discussion of the mechanical and optical principles used in the various long baseline systems in operation around the world - LIGO (USA), Virgo (Italy/France), TAMA300 and LCGT (Japan), and GEO600 (Germany/U.K.) - and in LISA, a proposed space-borne interferometer. A review of recent science runs from the current generation of ground-based detectors will be discussed, in addition to highlighting the astrophysical results gained thus far. Looking to the future, the major upgrades to LIGO (Advanced LIGO), Virgo (Advanced Virgo), LCGT and GEO600 (GEO-HF) will be completed over the coming years, which will create a network of detectors with significantly improved sensitivity required to detect gravitational waves. Beyond this, the concept and design of possible future "third generation" gravitational wave detectors, such as the Einstein Telescope (ET), will be discussed.Comment: Published in Living Reviews in Relativit

    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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    Coalescence of Black Hole-Neutron Star Binaries

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