783 research outputs found

    Storm-induced precipitation variability control of long-term erosion

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    International audienceErosion is often treated as a continuous process, yet it occurs through discrete events such as floods and landslides of variable magnitude and periodicity. It has also long been expected to be strongly dependent on precipitation, however, the influence of temporal rainfall variability upon long-term evolution of landscapes remains unclear. Here we report high erosion rates (0.8 to ∼10 mmyr−1over ∼70 ka) estimated from paleovolcanic reconstructions across a steep rainfall gradient on Reunion Island, which show that long-term erosion rates are influenced by the cyclone-induced variability of precipitation. Geostatistical analysis of 30 years of daily rainfall records reveals that erosion rates are high where the local climate is the driest and where the difference in intensity between extreme rainfall events and prevailing precipitation is the strongest. This implies that the intrinsic variability of precipitation impacts landscape evolution not only through extreme meteorological events, but also through background rainfall-induced parameters such as humidity and dryness, which modulate the erosion threshold of the Earth’s Critical Zone

    Improving the Quality of Elder Care: The Continuing Care Retirement Community

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    Includes bibliographical references.By 2020, the segment of the population 65 and older will have increased by 42% to reach over one million persons and those 85 and older will number roughly 129,000. These trends indicate an increase in the demands for social services, such as housing and formal health care, including long-term nursing care. One option that provides for the needs of the elderly is the Continuing Care Retirement Community (CCRC)

    Endometrial response to IVF hormonal manipulation: Comparative analysis of menopausal, down regulated and natural cycles

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    BACKGROUND: Uterine luminal epithelial cell response to different hormonal strategies was examined to determine commonality when an endometrium attains a receptive, stimulated, morphological profile that may lead to successful implantation. METHODS: Endometrial biopsies from 3 cohorts of patients were compared. The tissue samples taken from these patients were categorized into 8 different groups according to their baseline and the hormone regime used. RESULTS: Pre-treatment natural cycle tissue was variable in appearance. Downregulation with a GnRH analogue tissue appeared menopausal in character. HRT after downregulation resulted in tissue uniformity. HRT in menopause resulted in a 'lush' epithelial surface. HST in the natural cycle improved the morphology with significant difference in secretion between the two regimes examined. CONCLUSIONS: Down regulation plus HRT standardized surface appearance but tissue response is significantly different from the natural cycle, natural cycle plus HRT or menopause plus HRT. HRT in menopause reinstates tissue to a state similar to a natural cycle but significantly different from a natural cycle plus HST. HST with a natural cycle is similar to tissue from the natural cycle but significant differences reflect the influence of the particular hormones present (at any point) within the cycle

    Congenital absence of inferior vena cava and thrombosis: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>A congenitally absent Inferior Vena Cava (IVC) is a rare anomaly that is recognised to be associated with idiopathic Deep Venous Thrombosis (DVT), particularly in the young. It may not be apparent until later in life. Retrospectively, as discussed in this case, there can be clues indicating the presence of such an anomaly from a young age. However, it is not clear whether early recognition of this condition would affect the prognosis and treatment.</p> <p>Case presentation</p> <p>A 54 year old gentleman was admitted with 3 weeks of abdominal pain and localised swelling over the right flank. Examination revealed palpable 'snake-like' tortuous, tender lumps on the abdominal wall. Past history revealed chronic non-healing venous leg ulcers, and varicose veins necessitating varicose vein ligation at a very young age. The ulcers eventually needed skin grafting.</p> <p>During this, current admission he was investigated and diagnosed with Deep Vein Thrombosis (DVT). CT scan, performed to search for intra-abdominal cancer, revealed absence of the Inferior Vena Cava with extensive thrombosed collaterals of the superficial abdominal and azygous veins and a congenitally atrophic left kidney.</p> <p>Conclusion</p> <p>This is a case of one of the oldest patient described in the literature to be diagnosed with absence of the IVC. It is thought that IVC anomalies are under-diagnosed, and may be commoner than once believed. However there were vital clues in his previous medical history suspicious for an underlying venous anomaly. Idiopathic DVT in a relatively young person with a past history of chronic leg ulceration or varicose veins should be investigated for congenital anomalies of the IVC. This is best achieved by CT scan of the abdomen.</p

    Change in incidence rates for psychosis in different ethnic groups in south London: findings from the Clinical Record Interactive Search-First Episode Psychosis (CRIS-FEP) study

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    Background: A higher incidence of psychotic disorders has been consistently reported among black and other minority ethnic groups, particularly in northern Europe. It is unclear whether these rates have changed over time. Methods: We identified all individuals with a first episode psychosis who presented to adult mental health services between 1 May 2010 and 30 April 2012 and who were resident in London boroughs of Lambeth and Southwark. We estimated age-and-gender standardised incidence rates overall and by ethnic group, then compared our findings to those reported in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses (ÆSOP) study that we carried out in the same catchment area around 10 years earlier. Results: From 9109 clinical records we identified 558 patients with first episode psychosis. Compared with ÆSOP, the overall incidence rates of psychotic disorder in southeast London have increased from 49.4 (95% confidence interval (CI) 43.6–55.3) to 63.1 (95% CI 57.3–69.0) per 100 000 person-years at risk. However, the overall incidence rate ratios (IRR) were reduced in some ethnic groups: for example, IRR (95% CI) for the black Caribbean group reduced from 6.7 (5.4–8.3) to 2.8 (2.1–3.6) and the ‘mixed’ group from 2.7 (1.8–4.2) to 1.4 (0.9–2.1). In the black African group, there was a negligible difference from 4.1 (3.2–5.3) to 3.5 (2.8–4.5). Conclusions: We found that incidence rates of psychosis have increased over time, and the IRR varied by the ethnic group. Future studies are needed to investigate more changes over time and determinants of change

    Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

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    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the \lambda=2.2-4.5\mic range when pumping at \lambda_1=1.2-1.8\mic. The exact phase-matching point depends on the soliton wavelength, and we show that a simple longpass filter can separate the Cherenkov waves from the solitons. The Cherenkov waves are born few-cycle with an excellent Gaussian pulse shape, and the conversion efficiency is up to 25%. Thus, optical Cherenkov waves formed with cascaded nonlinearities could become an efficient source of energetic near- to mid-IR few-cycle pulses.Comment: Extended version of Nonlinear Optics 2011 contribution http://www.opticsinfobase.org/abstract.cfm?URI=NLO-2011-NTuA7. Submitted for Optics Express special issue for NLO conferenc

    Isospin-1/2 DπD\pi scattering and the lightest D0∗D_0^\ast resonance from lattice QCD

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    Isospin-1/2 DπD\pi scattering amplitudes are computed using lattice QCD, working in a single volume of approximately (3.6  fm)3(3.6\; \mathrm{fm})^3 and with a light quark mass corresponding to mπ≈239m_\pi\approx239 MeV. The spectrum of the elastic DπD\pi energy region is computed yielding 20 energy levels. Using the L\"uscher finite-volume quantisation condition these energies are translated into constraints on the infinite volume scattering amplitudes. For the first time, we find a complex D0∗D_0^\ast resonance pole from lattice QCD, strongly coupled to the SS-wave DπD\pi channel, with a mass m≈2200m\approx 2200 MeV and a width Γ≈400\Gamma\approx400 MeV. Combined with earlier work investigating the Ds0∗D_{s0}^\ast, and D0∗D_0^\ast with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the D0∗D_0^\ast is consistently found well below that of the Ds0∗D_{s0}^\ast, in contrast to the currently reported experimental result.Comment: 39 pages, 13 figure

    Evaluation of the Effects of Powder Coating Cure Temperatures on the Mechanical Properties of Aluminum Alloy Substrates

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    The effects of curing temperature, based on new, low-temperature powder coating methods and traditional high-temperature powder coating methods, were studied. Heat-sensitive aluminum alloys (2024-T3, 6061-T6, and 7075-T6) were subjected to two different heat-treatment cycles, which were based on temperatures of 121 and 204 degrees C. Findings indicate that although both cure temperatures achieved powder coatings adhesion and thickness appropriate for industrial uses, the high-temperature cure treatment negatively affected the mechanical properties

    Model-independent determination of the dipole response of <sup>66</sup>Zn using quasimonoenergetic and linearly polarized photon beams

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    Background: Photon strength functions are an important ingredient in calculations relevant for the nucleosynthesis of heavy elements. The relation to the photoabsorption cross section allows to experimentally constrain photon strength functions by investigating the photoresponse of atomic nuclei. Purpose: We determine the photoresponse of 66Zn in the energy region of 5.6 MeV to 9.9 MeV and analyze the contribution of the 'elastic' decay channel back to the ground state. In addition, for the elastic channel electric and magnetic dipole transitions were separated. Methods: Nuclear resonance fluorescence experiments were performed using a linearly polarized quasi-monoenergetic photon beam at the High Intensity gamma -ray Source. Photon beam energies from 5.6 to 9.9 MeV with an energy spread of about 3% were selected in steps of 200-300 keV. Two high purity germanium detectors were used for the subsequent gamma -ray spectroscopy. Results: Full photoabsorption cross sections are extracted from the data making use of the monoenergetic character of the photon beam. For the ground-state decay channel, the average contribution of electric and magnetic dipole strengths is disentangled. The average Conclusions: The new results indicate lower cross sections when compared to the values extracted from a former experiment using bremsstrahlung on 66Zn. In the latter, the average branching ratio to the ground state is estimated from statistical-model calculations in order to analyze the data. Corresponding estimates from statistical-model calculations underestimate this branching ratio compared to the values extracted from the present analysis, which would partly explain the high cross sections determined from the bremsstrahlung data
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