962 research outputs found

    Optokinetic stimulation rehabilitation in preventing seasickness

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    SummaryObjectivesSeasickness occurs when traveling on a boat: symptoms such as vomiting are very disturbing and may be responsible for discontinuing travel or occupation and can become life-threatening. The failure of classical treatment to prevent seasickness has motivated this retrospective study exploring optokinetic stimulation in reducing these symptoms.Patients and methodsExperimental training of 75 sailors with optokinetic stimulation attempted to reduce seasickness manifestations and determine the factors that could predict accommodation problems.ResultsEighty percent of the trained subjects were able to return on board. No predictive factors such as sex, occupation, degree of illness, number of treatment sessions, time to follow-up, and age were found to influence training efficacy.ConclusionOptokinetic stimulation appears to be promising in the treatment of seasickness. Nevertheless, statistically significant results have yet to demonstrate its efficacy

    Cell-specific discrimination of desmosterol and desmosterol mimetics confers selective regulation of LXR and SREBP in macrophages.

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    Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of sterol regulatory element-binding protein (SREBP)1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c-induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytes in vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophages in vitro and in vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in the liver that lead to hypertriglyceridemia

    Effects of sand extraction on the macrobenthos of the Belgian Continental Shelf: a comparison of long-term datasets: Thesis summary

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    Stations sampled on the Kwintebank in late seventies, mid nineties and 2001 were used to detect possible changes in macrobenthic communities related to the impact of sand extraction. The community analysis based on data covering the entire sandbank in the nineties, failed to detect a difference between stations subject to high sand extraction and stations subject to low sand extraction on the sandbank. Comparing the community analyses of the seventies and 2001 no real community shift could be detected, except the indications in the depression. But an overall decrease in density and diversity is defined at all stations in 2001 relative to the seventies. The most intensive sand extraction is situated at the centre and the northern part of the sandbank, where both geomorphological and granulometric as meiofauna communities are affected by sand extraction. For macrofauna there is no clear evidence for a change in community structure in the north and the centre due to the impact of sand extraction, although some clear changes in density, diversity and sediment grain size are recorded in these two most impacted areas. Although methodological problems enhanced the difficulties in comparing the results of the seventies with the nineties and 2001, Hesionura elongata was considered to be a suitable indicator for human disturbances

    SOFIA FEEDBACK Survey: The Pillars of Creation in [C II] and Molecular Lines

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    We investigate the physical structure and conditions of photodissociation regions (PDRs) and molecular gas within the Pillars of Creation in the Eagle Nebula using SOFIA FEEDBACK observations of the [C II] 158 micron line. These observations are velocity resolved to 0.5 km s−1^{-1} and are analyzed alongside a collection of complimentary data with similar spatial and spectral resolution: the [O I] 63 micron line, also observed with SOFIA, and rotational lines of CO, HCN, HCO+^{+}, CS, and N2_2H+^{+}. Using the superb spectral resolution of SOFIA, APEX, CARMA, and BIMA, we reveal the relationships between the warm PDR and cool molecular gas layers in context of the Pillars' kinematic structure. We assemble a geometric picture of the Pillars and their surroundings informed by illumination patterns and kinematic relationships and derive physical conditions in the PDRs associated with the Pillars. We estimate an average molecular gas density nH2∼1.3×105n_{{\rm H}_2} \sim 1.3 \times 10^5 cm−3^{-3} and an average atomic gas density nH∼1.8×104n_{\rm H} \sim 1.8 \times 10^4 cm−3^{-3} and infer that the ionized, atomic, and molecular phases are in pressure equilibrium if the atomic gas is magnetically supported. We find pillar masses of 103, 78, 103, and 18 solar masses for P1a, P1b, P2, and P3 respectively, and evaporation times of ∼\sim1-2 Myr. The dense clumps at the tops of the pillars are currently supported by the magnetic field. Our analysis suggests that ambipolar diffusion is rapid and these clumps are likely to collapse within their photoevaporation timescales.Comment: 42 pages, 16 figures. Accepted for publication in The Astronomical Journa

    Transitional waters North East Atlantic geographic intercalibration group: Benthic invertebrate fauna ecological assessment methods

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    This report gives a technical description on the intercalibration (IC) process of the different benthic assessment approaches for soft sediment habitats (muds to sands) in transitional waters in the North East Atlantic Geographical Intercalibration Group (NEA-GIG) for type NEA 11 (Transitional Waters). Eight member states are involved: Belgium (BE), France (FR), Germany (DE), Ireland (RoI), the Netherlands (NL), Portugal (PT), Spain (SP), and United Kingdom (UK). In Spain, the competent authorities for the WFD application are the regions, as such, for the benthic macroinvertebrates assessment methods three regions have been considered: Andalusia (SP-An), Basque Country (SP-BC) and Cantabria (SP-C). Those member states proposed 7 approaches for IC: AeTV (DE), BAT (PT), BEQI (BE), BEQI2 (NL), IQI (RoI and UK), M-AMBI (DE and SP-BC), QSB (SP-C) and TAsBeM (SP-An). However, AeTV and BEQI are not intercalibrated as they assess benthic invertebrates at water body and ecosystem level, respectively, whereas the rest of methods assess the benthic status at sample level.JRC.D.2-Water and Marine Resource

    Higgs After the Discovery: A Status Report

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    Recently, the ATLAS and CMS collaborations have announced the discovery of a 125 GeV particle, commensurable with the Higgs boson. We analyze the 2011 and 2012 LHC and Tevatron Higgs data in the context of simplified new physics models, paying close attention to models which can enhance the diphoton rate and allow for a natural weak-scale theory. Combining the available LHC and Tevatron data in the ZZ* 4-lepton, WW* 2-lepton, diphoton, and b-bbar channels, we derive constraints on the effective low-energy theory of the Higgs boson. We map several simplified scenarios to the effective theory, capturing numerous new physics models such as supersymmetry, composite Higgs, dilaton. We further study models with extended Higgs sectors which can naturally enhance the diphoton rate. We find that the current Higgs data are consistent with the Standard Model Higgs boson and, consequently, the parameter space in all models which go beyond the Standard Model is highly constrained.Comment: 37 pages; v2: ATLAS dijet-tag diphoton channel added, dilaton and doublet-singlet bugs corrected, references added; v3: ATLAS WW channel included, comments and references adde

    Inorganic chlorine partitioning in the summer lower stratosphere: Modeled and measured [ClONO_2]/[HCl] during POLARIS

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    We examine inorganic chlorine (Cl_y,) partitioning in the summer lower stratosphere using in situ ER-2 aircraft observations made during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) campaign. New steady state and numerical models estimate [ClONO_2]/[HCl] using currently accepted photochemistry. These models are tightly constrained by observations with OH (parameterized as a function of solar zenith angle) substituting for modeled HO_2 chemistry. We find that inorganic chlorine photochemistry alone overestimates observed [ClONO_2]/[HCl] by approximately 55–60% at mid and high latitudes. On the basis of POLARIS studies of the inorganic chlorine budget, [ClO]/[ClONO_2], and an intercomparison with balloon observations, the most direct explanation for the model-measurement discrepancy in Cl_y, partitioning is an error in the reactions, rate constants, and measured species concentrations linking HCl and ClO (simulated [ClO]/[HCl] too high) in combination with a possible systematic error in the ER-2 ClONO_2 measurement (too low). The high precision of our simulation (±15% 1σ for [ClONO_2]/[HCl], which is compared with observations) increases confidence in the observations, photolysis calculations, and laboratory rate constants. These results, along with other findings, should lead to improvements in both the accuracy and precision of stratospheric photochemical models
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