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We propose a new measurement of the ratio of positron-proton to electron-proton elastic scattering at DESY. The purpose is to determine the contributions beyond single-photon exchange, which are essential for the Quantum Electrodynamic (QED) description of the most fundamental process in hadronic physics. By utilizing a 20 cm long liquid hydrogen target in conjunction with the extracted beam from the DESY synchrotron, we can achieve an average luminosity of 2.12 × 10 35 cm - 2 · s - 1 ( ≈ 200 times the luminosity achieved by OLYMPUS). The proposed two-photon exchange experiment (TPEX) entails a commissioning run at a beam energy of 2 GeV, followed by measurements at 3 GeV, thereby providing new data up to Q 2 = 4.6 (GeV/c) 2 (twice the range of current measurements). We present and discuss the proposed experimental setup, run plan, and expectations. [ABSTRACT FROM AUTHOR]

Educational resources can be easily found on the Web. Most search engines base their algorithms on a resource's text or popularity, requiring teachers to navigate the results until they find an appropriate resource. This makes searching for resources a tedious and cumbersome task. Specialized repositories contain resources that are annotated with metadata that aim to facilitate the discovery of quality resources. Nevertheless, the abundance and variety of content make searching a complex task. Recommender systems can assist teachers in finding the proper content by determining clusters of similar users and inferring users interest in a resource, assembling clusters of similar resources, or a mix of both. Probabilistic model-based (PMB) techniques, on the other hand, make it possible to classify resources into more than one cluster with various degrees of probability. In this paper, we used recommender systems and PMB techniques to analyze a dataset produced by primary and secondary level teachers over the course of four years and under natural conditions. We found that a hybrid recommendation, the Collaborative Topic Regression (CTR) technique, performs better than other approaches despite the high sparseness of the dataset. In addition, learning resources annotated with curriculum metadata had a positive impact on recommender's accuracy whereas free-text or other metadata negatively impacted the results. [ABSTRACT FROM AUTHOR]

The NPDGamma experiment measures the parity-violating (PV) gamma asymmetry from polarized cold neutrons captured on protons at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The (PV) neutron spin asymmetry A of photons from polarized cold neutron capture on protons is proportional to the Δ I=1 long range weak meson coupling $h_{\pi }^{1}$ between nucleons in the hadronic weak interaction (HWI). Liquid para-hydrogen production data taking concluded in April 2014 and once the background aluminum asymmetry measurements are complete, the PV asymmetry A can be extracted. Preliminary results of the analysis of A are presented. [ABSTRACT FROM AUTHOR]

We present a theoretical and experimental analysis of the joint effects of the transverse electric field distribution and of the nonlinear crystal characteristics on the properties of photon pairs generated by spontaneous parametric downconversion (SPDC). While it is known that for a sufficiently short crystal the pump electric field distribution fully determines the joint signal-idler properties, for longer crystals the nonlinear crystal properties also play an important role. In this paper we present experimental measurements of the angular spectrum (AS) and of the conditional angular spectrum (CAS) of photon pairs produced by SPDC, carried out through spatially resolved photon counting. In our experiment we control whether or not the source operates in the short-crystal regime through the degree of pump focusing, and explicitly show how the AS and CAS measurements differ in these two regimes. Our theory provides an understanding of the boundary between these two regimes and also predicts the corresponding differing behaviors. [ABSTRACT FROM AUTHOR]

At the MIT-Bates Linear Accelerator Center, the nucleon form factors have been measured by scattering polarized electrons from vector-polarized hydrogen and deuterium. The experiment used the longitudinally polarized electron beam stored in the MIT-Bates South Hall Ring along with an isotopically pure, highly vector-polarized internal atomic hydrogen and deuterium target provided by an atomic beam source. The measurements were carried out with the symmetric Bates Large Acceptance Spectrometer Toroid (BLAST). Results are presented for the proton form factor ratio, $\mu_p G_E^p/G_M^p$, and for the charge form factor of the neutron, $G_E^n$. Both results are more precise than previous data in the corresponding Q2 ranges. [ABSTRACT FROM AUTHOR]

Measurements of the charge and magnetic form factors of the nucleon present a sensitive test of nucleon models and QCD-inspired theories. A precise knowledge of the neutron form factors at low Q2 is also essential to reduce the systematic errors of parity-violation experiments. At the MIT-Bates Linear Accelerator Center, the nucleon form factors have been measured by means of scattering of polarized electrons from vector-polarized hydrogen and deuterium. The experiment used the longitudinally polarized stored electron beam of the MIT-Bates South Hall Ring along with an isotopically pure, highly vector-polarized internal atomic hydrogen and deuterium target provided by an atomic beam source. The measurements have been carried out with the symmetric Bates Large-Acceptance Spectrometer Toroid (BLAST) with enhanced neutron detection capability. [ABSTRACT FROM AUTHOR]

Measurements of the electric and magnetic form factors of the nucleon present a sensitive test of nucleon models and QCD-inspired theories. A precise knowledge of the neutron form factors at low Q2 is also essential to reduce the systematic errors of parity violation experiments. At the MIT-Bates Linear Accelerator Center, the nucleon form factors have been measured by means of scattering of polarized electrons from vector-polarized hydrogen and deuterium. The experiment used the longitudinally polarized stored electron beam of the MIT-Bates South Hall Ring along with an isotopically pure, highly vector-polarized internal atomic hydrogen and deuterium target provided by an atomic beam source. The measurements have been carried out with the symmetric Bates Large Acceptance Spectrometer Toroid (BLAST) with enhanced neutron detection capability. [ABSTRACT FROM AUTHOR]

The BLAST detector is presently under construction by an international collaboration of 11 institutions. A description of the detector and its present status are briefly presented. The initial scientific program calls for comprehensive measurements of the spin dependent electromagnetic response of the few body systems. The experiments are carried out with a recirculating, continuous polarized electron beam of up to 1 (GeV), polarized internal gas targets and the large acceptance magnetic detector. As examples, projected results in the accessible Q 2-range are presented for the charge form factor of the neutron G E n and the T 20 observable from elastic scattering off tensor polarized deuterium. [ABSTRACT FROM AUTHOR]

Neuropsychiatric complications of chronic renal haemodialysis cover a wide gamut of clinical syndromes. These pictures can be diagnostically classified as non-psychotic and psychtic-like syndromes. On the basis of a review of the literature, some nosological precisions are formulated, and a hypothesized cognitive-behavioural psychopathological continuum is presented. The hypothesis postulates that a central cognitive disturbance, due to multiple organic aetiopathogenic factors, results in a stepwise decline, initially disguised as an affective, neurotic or personality disorder, and further deteriorating into the well-known 'dialysis dementia', with a variety of other clinical presentations in between. Additional research in the biological and psychosocial areas is needed to verify different aspects of these conditions, their validity in the context of the authors' hypothesis, and their relevance to the overall 'quality of life' of chronic haemodialysis patients. [ABSTRACT FROM AUTHOR]

Sixteen patients in whom schizophrenia was initially diagnosed and who were treated with fluphenazine enanthate or decanoate developed severe depression for a short period after the injection. In five cases this depression is thought to have been responsible for suicide. In 8 out of 10 cases the depression responded to electroplexy (E.C.T.). It is recommended that patients who are treated with fluphenazine should be carefully supervised. [ABSTRACT FROM PUBLISHER]

The article discusses the study which aims to present an enumerative survey of abuse of heroin and methadone among persons aged 30 and below in Oxford, England in 1969. The sources used in this survey include the press, the city children's department, local authority and independent schools, the police, the Oxford Probation Service, hospitals, general practitioners, the city's Medical Officer of Health, and drug users. The study reveals that there is high relative prevalence of dependence in girls aged 15-19, and there is a statistically significant difference from the sex distribution in the Registrar General's Annual Estimates.