The spin structure of the proton at low xx and low Q2Q^2 in two-dimensional bins from COMPASS

The longitudinal double spin asymmetries $A_1^p$ and the spin dependent structure function of the proton $g_1^p$ were extracted from COMPASS data in the region of low Bjorken scaling variable $x$ and low photon virtuality $Q^2$. The data were taken in 2007 and 2011 from scattering of polarised muons off polarised protons, resulting in a sample that is 150 times larger than the one from the previous experiment SMC that pioneered studies in this kinematic region. For the first time, $A_1^p$ and $g_1^p$ were evaluated in this region in two-dimensional bins of kinematic variables: $(x,Q^2)$, $(\nu ,Q^2)$, $(x,\nu)$ and $(Q^2,x)$. The following kinematic region was investigated: $4\times 10^{-5}<x<4\times 10^{-2}$, $0.001$~(GeV/$c$)$^2<Q^2<1$~(GeV/$c$)$^2$ and $14$~GeV$<\nu <194$~GeV. The obtained results were confronted with theoretical models.Comment: 5 pages, 3 figures, DIS 2016 Conference Proceedings, to appear in the proceedings of the XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects, DESY Hamburg, Germany, April 11-15, 201

Longitudinal double spin asymmetry A1pA_1^p and spin-dependent structure function g1pg_1^p of the proton at low xx and low Q2Q^2 from COMPASS

The COMPASS experiment at CERN has collected a large sample of events of inelastic scattering of longitudinally polarised muons off longitudinally polarised protons in the non-perturbative region (four-momentum transfer squared $Q^2<1$ GeV$^2$/$c^2$), with a Bjorken scaling variable in the range $4\times 10^{-5}<x<4\times 10^{-2}$. The data set is two orders of magnitude larger than the similar sample collected by the SMC experiment. These data complement our data for polarised deuterons. They allow the accurate determination of the longitudinal double spin asymmetry $A_1^p$ and of the spin-dependent structure function $g_1^p$ of the proton in the region of low $x$ and low $Q^2$. The preliminary results of the analysis of these data yield non zero and positive asymmetries and of the structure function $g_1^p$. This is the first time that spin effects are observed at such low $x$.Comment: 4 pages, 6 figures, DSPIN-13 Conference Proceedings, to appear in the proceedings of the XV Workshop on High Energy Spin Physics, Dubna, Russia, October 8-12, 201

Information systems evaluation methodologies

Due to the prevalent use of Information Systems (IS) in modern organisations nowadays, evaluation research in this field is becoming more and more important. In light of this, a set of rigorous methodologies were developed and used by IS researchers and practitioners to evaluate the increasingly complex IS implementation used. Moreover, different types of IS and different focusing perspectives of the evaluation require the selection and use of different evaluation approaches and methodologies. This paper aims to identify, explore, investigate and discuss the various key methodologies that can be used in IS evaluation from different perspectives, namely in nature (e.g. summative vs. formative evaluation) and in strategy (e.g. goal-based, goal-free and criteria-based evaluation). The paper concludes that evaluation methodologies should be selected depending on the nature of the IS and the specific goals and objectives of the evaluation. Nonetheless, it is also proposed that formative criteria-based evaluation and summative criteria-based evaluation are currently among the most and more widely used in IS research. The authors suggest that the combines used of one or more of these approaches can be applied at different stages of the IS life cycle in order to generate more rigorous and reliable evaluation outcomes

Energy and volume of vector fields on spherical domains

We present in this paper a \boundary version" for theorems about minimality of volume and energy functionals on a spherical domain of threedimensional Euclidean sphere

Cerebral and cardiovascular effects of analgesic doses of ketamine during a target controlled general anesthesia: a prospective randomized study

Introduction: Ketamine is increasingly being used in various pain settings. The purpose of this study was to assess the effect of an analgesic dose of ketamine in the bispectral index (BIS), spectral edge frequency (SEF-95), density spectral array (DSA), cerebral oximetry (rSO2) and mean arterial pressure (MAP) during general anaesthesia with a target controlled infusion. Methods: A prospective, single-blinded and randomized study on adult patients scheduled for elective spine surgery was carried out. After anaesthesia induction with propofol, remifentanil and rocuronium, when a stable BIS value (45-55) was achieved, an automatic recording of BIS, SEF-95, rSO2 and MAP values during 9 min was performed to establish patients baseline values. Subsequently, patients were randomly assigned to receive a ketamine bolus dose of 0.2 mg/kg, 0.5 mg/kg or 1 mg/kg; all variables were recorded for additional 9 min after the ketamine bolus, in the absence of any surgical stimulus. A p-value <0.05 was considered significant in the statistical analysis. Results and discussion: Thirty-nine patients were enrolled in the study. Our results show a dose-related increase of SEF-95 and BIS values. DSA demonstrate a shift in the frequency range and power distribution towards higher frequencies. Our results do not show significant differences in MAP and rSO2 values. Conclusion: When ketamine is used intraoperatively in analgesic doses, the anaesthetist should anticipate an increase in SEF-95 and BIS values which will not be associated with the level of anaesthesia.info:eu-repo/semantics/publishedVersio

Temperature dependence of the coercive field in single-domain particle systems

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and explains well the experimental behavior over a wide temperature range. The coexistence of blocked and unblocked particles for a given temperature rises difficulties that are solved here by introducing a temperature dependent blocking temperature. An empirical factor gamma arise from the model and is directly related to the particle interactions. The proposed generalized model describes well the experimental results and can be applied to other single-domain particle system.Comment: 7 pages, 8 figures, revised version, accepted to Physical Review B on 29/04/200