1,000 research outputs found

    Use of apomorphine in Parkinsonian patients with neuropsychiatric complications to oral treatment

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    Neuropsychiatric side effects often complicate anti-Parkinsonian therapy and pose a significant problem in the optimal management of idiopathic Parkinson's disease. Several publications report a relative lack of neuropsychiatric side effects in Parkinsonian patients treated with subcutaneous apomorphine. To investigate this further, we have used subcutaneous apomorphine to treat 12 non-demented IPD patients with previous oral drug-related neuropsychiatric problems. Treatment with apomorphine allowed alteration of anti-Parkinsonian medication and led to the abolition or reduction of neuropsychiatric complications in all patients. The mechanism remains unclear but may be due, in part, to a reduction in oral medication or a psychotropic action of apomorphine, possibly due to the piperidine moiety in its structure, or both

    An investigation into the inactivation kinetics of hydrogen peroxide vapor against clostridium difficile endospores

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    C. difficile spores are resistant to routine cleaning agents and are able to survive on inanimate surfaces for long periods of time. There is increasing evidence of the importance of the clinical environment as a reservoir for pathogenic agents and as a potential source of healthcare-associated infections (HCAIs). In this context, to reduce the risk of cross-transmission, terminal disinfection of hospital wards and isolation rooms using hydrogen peroxide vapor (HPV) is attracting attention. Spores of C. difficile (ribotype 027) were exposed to constant concentrations of HPV ranging between 11 and 92 mg m−3 (ppm) for a range of exposure times in a specially designed chamber. The inactivation data thus obtained was fitted using the modified Chick–Watson inactivation model to obtain decimal reduction values (D values). D values ranged from 23 to 1.3 min at HPV concentrations of 11 and 92 ppm, respectively. We present a simple mathematical model based on the inactivation kinetic data obtained here to estimate the efficacy of commercial HPV processes used in healthcare environmental decontamination. C. difficile spores showed linear inactivation kinetics at steady HPV concentrations ranging between 10 and 90 ppm. The data obtained here was used to provide estimates of the inactivation efficacy of commercial HPV process cycles, which employ unsteady HPV concentrations during the decontamination process

    Precise calculation of parity nonconservation in cesium and test of the standard model

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    We have calculated the 6s-7s parity nonconserving (PNC) E1 transition amplitude, E_{PNC}, in cesium. We have used an improved all-order technique in the calculation of the correlations and have included all significant contributions to E_{PNC}. Our final value E_{PNC} = 0.904 (1 +/- 0.5 %) \times 10^{-11}iea_{B}(-Q_{W}/N) has half the uncertainty claimed in old calculations used for the interpretation of Cs PNC experiments. The resulting nuclear weak charge Q_{W} for Cs deviates by about 2 standard deviations from the value predicted by the standard model.Comment: 24 pages, 8 figure

    Sparse classification with MRI based markers for neuromuscular disease categorization

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    International audienceIn this paper, we present a novel method for disease classification between two patient populations based on features extracted from Magnetic Resonance Imaging (MRI) data. Anatomically meaningful features are extracted from structural data (T1- and T2-weighted MR images) and Diffusion Tensor Imaging (DTI) data, and used to train a new machine learning algorithm, the k-support SVM (ksup-SVM). The k-support regularized SVM has an inherent feature selection property, and thus it eliminates the requirement for a separate feature selection step. Our dataset consists of patients that suffer from facioscapulohumeral muscular dystrophy (FSH) and Myotonic muscular dystrophy type 1 (DM1) and our proposed method achieves a high performance. More specifically, it achieves a mean Area Under the Curve (AUC) of 0.7141 and mean accuracy 77% ± 0.013. Moreover, we provide a sparsity visualization of the features in order to indentify their discriminative value. The results suggest the potential of the combined use of MR markers to diagnose myopathies, and the general utility of the ksup-SVM. Source code is also available at https://gitorious.org/ksup-svm

    Isospin Effects in Nuclear Multifragmentation

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    We develop an improved Statistical Multifragmentation Model that provides the capability to calculate calorimetric and isotopic observables with precision. With this new model we examine the influence of nuclear isospin on the fragment elemental and isotopic distributions. We show that the proposed improvements on the model are essential for studying isospin effects in nuclear multifragmentation. In particular, these calculations show that accurate comparisons to experimental data require that the nuclear masses, free energies and secondary decay must be handled with higher precision than many current models accord.Comment: 46 pages, 16 figure

    The 21 cm Signature of Cosmic String Wakes

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    We discuss the signature of a cosmic string wake in 21cm redshift surveys. Since 21cm surveys probe higher redshifts than optical large-scale structure surveys, the signatures of cosmic strings are more manifest in 21cm maps than they are in optical galaxy surveys. We find that, provided the tension of the cosmic string exceeds a critical value (which depends on both the redshift when the string wake is created and the redshift of observation), a cosmic string wake will generate an emission signal with a brightness temperature which approaches a limiting value which at a redshift of z+1=30z + 1 = 30 is close to 400 mK in the limit of large string tension. The signal will have a specific signature in position space: the excess 21cm radiation will be confined to a wedge-shaped region whose tip corresponds to the position of the string, whose planar dimensions are set by the planar dimensions of the string wake, and whose thickness (in redshift direction) depends on the string tension. For wakes created at zi+1=103z_i + 1 = 10^3, then at a redshift of z+1=30z + 1 = 30 the critical value of the string tension ÎŒ\mu is GÎŒ=6×10−7G \mu = 6 \times 10^{-7}, and it decreases linearly with redshift (for wakes created at the time of equal matter and radiation, the critical value is a factor of two lower at the same redshift). For smaller tensions, cosmic strings lead to an observable absorption signal with the same wedge geometry.Comment: 11 pages, 4 figures; a couple of comments added in the discussion sectio

    Interactions between proteins bound to biomembranes

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    We study a physical model for the interaction between general inclusions bound to fluid membranes that possess finite tension, as well as the usual bending rigidity. We are motivated by an interest in proteins bound to cell membranes that apply forces to these membranes, due to either entropic or direct chemical interactions. We find an exact analytic solution for the repulsive interaction between two similar circularly symmetric inclusions. This repulsion extends over length scales of order tens of nanometers, and contrasts with the membrane-mediated contact attraction for similar inclusions on tensionless membranes. For non circularly symmetric inclusions we study the small, algebraically long-ranged, attractive contribution to the force that arises. We discuss the relevance of our results to biological phenomena, such as the budding of caveolae from cell membranes and the striations that are observed on their coats.Comment: 22 pages, 2 figure

    Reflection and the art of coaching: fostering high-performance in olympic ski cross

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    In preparation for the 2010 Vancouver Winter Olympic Games, the lead author engaged in systematic reflection in an attempt to implement coaching behaviours and create practice environments that promoted athlete development (psycho-social and physical performance). The research was carried out in relation to his work as head Ski Cross coach working with (primarily) three athletes in their quest for Olympic qualification and subsequent performance success in the Olympic Games. This project sought to examine coach-athlete interactions. Of particular interest were coach and athlete responses regarding the implementation of autonomy supportive coaching behaviours in a high context. Autonomy supportive coaching behaviours have previously been strongly associated with positive athlete psycho-social and performance outcomes, however, a paucity of research has examined its implementation in high-performance contexts. Through the use of participant ethnography, it was possible to gain considerable insights regarding athletes' perceptions of choice, implications of perceived athletic hierarchies, as well as cultural and experience-related influences on training and performance expectations

    Standard Model baryogenesis through four-fermion operators in braneworlds

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    We study a new baryogenesis scenario in a class of braneworld models with low fundamental scale, which typically have difficulty with baryogenesis. The scenario is characterized by its minimal nature: the field content is that of the Standard Model and all interactions consistent with the gauge symmetry are admitted. Baryon number is violated via a dimension-6 proton decay operator, suppressed today by the mechanism of quark-lepton separation in extra dimensions; we assume that this operator was unsuppressed in the early Universe due to a time-dependent quark-lepton separation. The source of CP violation is the CKM matrix, in combination with the dimension-6 operators. We find that almost independently of cosmology, sufficient baryogenesis is nearly impossible in such a scenario if the fundamental scale is above 100 TeV, as required by an unsuppressed neutron-antineutron oscillation operator. The only exception producing sufficient baryon asymmetry is a scenario involving out-of-equilibrium c quarks interacting with equilibrium b quarks.Comment: 39 pages, 5 figures v2: typos, presentational changes, references and acknowledgments adde
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