2,795 research outputs found

    The Recoil Proton Polarization: a new discriminative DVCS observable

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    Generalized parton distributions describe the correlations between the longitudinal momentum and the transverse position of quarks and gluons in a nucleon. They can be constrained by measuring photon leptoproduction observables, arising from the interference between Bethe-Heitler and Deeply virtual Compton scattering processes. At leading-twist/leading-order, the amplitude of the latter is parameterized by complex integrals of the GPDs {H, E, \~H, \~E} . As data collected on an unpolarized or longitudinally polarized target constrains H and \~H, E is poorly known as it requires data collected with a transversely polarized target, which is very challenging to implement in fixed target experiments. The only alternative considered so far has been DVCS on a neutron with a deuterium target, while assuming isospin symmetry and absence of final-state interactions. Today, we introduce the polarization of the recoil proton as a new DVCS observable, highly sensitive to E, which appears feasible for an experimental study at a high-luminosity facility such as Jefferson Lab

    No evidence for embodiment: The motor system is not needed to keep action words in working memory

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    Increasing evidence implicates the sensorimotor systems with high-level cognition, but the extent to which these systems play a functional role remains debated. Using an elegant design, Shebani and Pulvermüller (2013) reported that carrying out a demanding rhythmic task with the hands led to selective impairment of working memory for hand-related words (e.g., clap), while carrying out the same task with the feet led to selective memory impairment for foot-related words (e.g., kick). Such a striking double dissociation is acknowledged even by critics to constitute strong evidence for an embodied account of working memory. Here, we report on an attempt at a direct replication of this important finding. We followed a sequential sampling design and stopped data collection at N=77 (more than five times the original sample size), at which point the evidence for the lack of the critical selective interference effect was very strong (BF01 = 91). This finding constitutes strong evidence against a functional contribution of the motor system to keeping action words in working memory. Our finding fits into the larger emerging picture in the field of embodied cognition that sensorimotor simulations are neither required nor automatic in high-level cognitive processes, but that they may play a role depending on the task. Importantly, we urge researchers to engage in transparent, high-powered, and fully pre-registered experiments like the present one to ensure the field advances on a solid basis

    Characterization of ␣ 2 Adrenergic Receptor Subtypes in Human Ocular Tissue Homogenates

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    PURPOSE. To determine the predominant ␣ 2 adrenergic receptor subtypes present in the human eye. METHODS. Saturation-and competition-receptor-binding experiments were performed with the radioligand [ 3 H]RX821002 in human ciliary body, retinal pigmented epithelium-choriocapillaris, iris, and neurosensory retina. The affinities of various adrenergic antagonists in these ocular tissues were compared with their affinities for the cloned ␣ 2A , ␣ 2B , and ␣ 2C adrenergic receptor subtypes. RESULTS. The density of ␣ 2 adrenergic receptors was highest in the iris (440 femtomoles/mg protein), lowest in the neurosensory retina (14 femtomoles/mg protein), and intermediate in the other two tissues (approximately 90 fmol/mg protein). The drug affinities in all four human ocular tissues were highly correlated (correlation coefficients between 0.94 and 0.97) with the affinities for the human ␣ 2A adrenergic receptor subtype and poorly correlated (correlation coefficients between 0.15 and 0.66) with the ␣ 2B and ␣ 2C subtypes. CONCLUSIONS. In agreement with previous studies in several animal species, the ␣ 2 adrenergic receptors in the human ciliary body, retinal pigmented epithelium-choriocapillaris, iris, and neurosensory retina are predominately of the ␣ 2A subtype. (Invest Ophthalmol Vis Sci. 1999;40: 2299 -2306 G laucoma is characterized by a progressive loss of visual sensitivity resulting from optic nerve damage. Because high intraocular pressure is the most important risk factor for glaucoma, the treatment of glaucoma has emphasized the reduction of intraocular pressure. 1 Alpha-2 adrenergic agonists such as brimonidine and apraclonidine are effective ocular hypotensive agents, 2-4 although their mechanism of action is not clear. Based on both pharmacologic and molecular evidence, there are three major types of adrenergic receptors, ␣ 1 , ␣ 2 , and ␤, each of which is further divided into three or four subtypes. 8 The evidence for ␣ 2 adrenergic receptor subtypes has come from binding and functional studies in various tissues and cell lines and more recently in cells transfected with the cDNA for the receptors. 9 On the basis of these studies, three ␣ 2 adrenergic receptor subtypes have been defined. The ␣ 2A adrenergic receptor subtype, for which prazosin has a relatively low affinity and oxymetazoline a relatively high affinity, is found in the human platelet and the HT29 cell. 11 Although this subtype also has a relatively high affinity for prazosin and a low affinity for oxymetazoline, it is pharmacologically distinct from the ␣ 2B subtype. 12 All three subtypes have been cloned from the human. In contrast to these binding data, immunofluorescence labeling of the human ciliary body indicates the presence of ␣ 2B and ␣ 2C subtypes, but not the ␣ 2A subtype

    Help or hindrance : young people's experiences of predictive testing for Huntington's disease

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    Funded by Scottish GovernmentPeer reviewedPublisher PD

    Sensitivity to point-like sources of the ALTO atmospheric particle detector array, designed for 200GeV\rm 200\,GeV--50TeV\rm 50\,TeV γ\gamma-ray astronomy

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    In the context of atmospheric shower arrays designed for γ\gamma-ray astronomy and in the context of the ALTO project, we present: a study of the impact of heavier nuclei in the cosmic-ray background on the estimated γ\gamma-ray detection performance on the basis of dedicated Monte Carlo simulations, a method to calculate the sensitivity to a point-like source, and finally the required observation times to reach a firm detection on a list of known point-like sources.Comment: 16 pages, 7 figures, accepted for publication in JHEAP (Journal of High-Energy Astrophysics

    Loop B is a major structural component of the 5-HT3 receptor

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    The 5-HT3 receptor belongs to a family of therapeutically important neurotransmitter-gated receptors whose ligand binding sites are formed by the convergence of six peptide loops (A-F). Here we have mutated 15 amino acid residues in and around loop B of the 5-HT3 receptor (Ser-177 to Asn-191) to Ala or a residue with similar chemical properties. Changes in [3H]granisetron binding affinity (Kd) and 5-HT EC50 were determined using receptors expressed in human embryonic kidney 293 cells. Substitutions at all but one residue (Thr-181) altered or eliminated binding for one or both mutants. Receptors were nonfunctional or EC50 values were altered for all but two mutants (S182T, I190L). Homology modeling indicates that loop B contributes two residues to a hydrophobic core that faces into the β-sandwich of the subunit, and the experimental data indicate that they are important for both the structure and the function of the receptor. The models also show that close to the apex of the loop (Ser-182 to Ile-190), loop B residues form an extensive network of hydrogen bonds, both with other loop B residues and with adjacent regions of the protein. Overall, the data suggest that loop B has a major role in maintaining the structure of the region by a series of noncovalent interactions that are easily disrupted by amino acid substitutions

    Impact of electrode geometry and thickness on planar on-chip microsupercapacitors

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    We report an assessment of the influence of both finger geometry and vertically-oriented carbon nanofiber lengths in planar micro-supercapacitors. Increasing the finger number leads to an up-scaling in areal power densities, which increases with scan rate. Growing the nanofibers longer, however, does not lead to a proportional growth in capacitance, proposedly related to limited ion penetration of the electrode

    Control of milk pasteurization process using model predictive approach

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    YesA milk pasteurization process, a nonlinear process and multivariable interacting system, is difficult to control by the conventional on-off controllers since the on-off controller can handled the temperature profiles for milk and water oscillating over the plant requirements. The multi-variable control approach with model predictive control (MPC) is proposed in this study. The proposed algorithm was tested for control of a milk pasteurization process in three cases of simulation such as set point tracking, model mismatch, difference control and prediction horizons, and time sample. The results for the proposed algorithm show the well performance in keeping both the milk and water temperatures at the desired set points without any oscillation and overshoot and giving less drastic control action compared to the cascade generic model control (GMC) strategy

    Formation of the Scandinavian Obesity Surgery Registry, SOReg.

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    Obesity surgery is expanding, the quality of care is ever more important, and learning curve assessment should be established. A large registry cohort can show long-term effects on obesity and its comorbidities, complications, and long-term side effects of surgery, as well as changes in health-related quality of life (QoL). Sweden is ideally suited to the task of data collection and audit, with universal use of personal identification numbers, nation-wide registries permitting cross-matching to analyze causes of death, in-hospital care, and health-related absenteeism
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