A surprising method for polarising antiprotons

We propose a method for polarising antiprotons in a storage ring by means of a polarised positron beam moving parallel to the antiprotons. If the relative velocity is adjusted to $v/c \approx 0.002$ the cross section for spin-flip is as large as about $2 \cdot 10^{13}$ barn as shown by new QED-calculations of the triple spin-cross sections. Two possibilities for providing a positron source with sufficient flux density are presented. A polarised positron beam with a polarisation of 0.70 and a flux density of approximately $1.5 \cdot 10^{10}$/(mm$^2$ s) appears to be feasible by means of a radioactive $^{11}$C dc-source. A more involved proposal is the production of polarised positrons by pair production with circularly polarised photons. It yields a polarisation of 0.76 and requires the injection into a small storage ring. Such polariser sources can be used at low (100 MeV) as well as at high (1 GeV) energy storage rings providing a time of about one hour for polarisation build-up of about $10^{10}$ antiprotons to a polarisation of about 0.18. A comparison with other proposals show a gain in the figure-of-merit by a factor of about ten.Comment: 13 pages, 8 figures; v2: minor language and signification corrections v3: (14 pages, 12 figures) major error, nonapplicable polarisation transfer cross sections replaced by the mandatory spin-flip cross section

Transport properties of strongly correlated metals:a dynamical mean-field approach

The temperature dependence of the transport properties of the metallic phase of a frustrated Hubbard model on the hypercubic lattice at half-filling are calculated. Dynamical mean-field theory, which maps the Hubbard model onto a single impurity Anderson model that is solved self-consistently, and becomes exact in the limit of large dimensionality, is used. As the temperature increases there is a smooth crossover from coherent Fermi liquid excitations at low temperatures to incoherent excitations at high temperatures. This crossover leads to a non-monotonic temperature dependence for the resistance, thermopower, and Hall coefficient, unlike in conventional metals. The resistance smoothly increases from a quadratic temperature dependence at low temperatures to large values which can exceed the Mott-Ioffe-Regel value, hbar a/e^2 (where "a" is a lattice constant) associated with mean-free paths less than a lattice constant. Further signatures of the thermal destruction of quasiparticle excitations are a peak in the thermopower and the absence of a Drude peak in the optical conductivity. The results presented here are relevant to a wide range of strongly correlated metals, including transition metal oxides, strontium ruthenates, and organic metals.Comment: 19 pages, 9 eps figure

Identification of T-Cell Antigens Specific for Latent Mycobacterium Tuberculosis Infection

BACKGROUND: T-cell responses against dormancy-, resuscitation-, and reactivation-associated antigens of Mycobacterium tuberculosis are candidate biomarkers of latent infection in humans. METHODOLOGY/PRINCIPAL FINDINGS: We established an assay based on two rounds of in vitro restimulation and intracellular cytokine analysis that detects T-cell responses to antigens expressed during latent M. tuberculosis infection. Comparison between active pulmonary tuberculosis (TB) patients and healthy latently M. tuberculosis-infected donors (LTBI) revealed significantly higher T-cell responses against 7 of 35 tested M. tuberculosis latency-associated antigens in LTBI. Notably, T cells specific for Rv3407 were exclusively detected in LTBI but not in TB patients. The T-cell IFNgamma response against Rv3407 in individual donors was the most influential factor in discrimination analysis that classified TB patients and LTBI with 83% accuracy using cross-validation. Rv3407 peptide pool stimulations revealed distinct candidate epitopes in four LTBI. CONCLUSIONS: Our findings further support the hypothesis that the latency-associated antigens can be exploited as biomarkers for LTBI

Nuclear expression of FLT1 and its ligand PGF in FUS-DDIT3 carrying myxoid liposarcomas suggests the existence of an intracrine signaling loop

<p>Abstract</p> <p>Background</p> <p>The FUS-DDIT3 fusion oncogene encodes an abnormal transcription factor that has a causative role in the development of myxoid/round-cell liposarcomas (MLS/RCLS). We have previously identified <it>FLT1 </it>(<it>VEGFR1</it>) as a candidate downstream target gene of FUS-DDIT3. The aim of this study was to investigate expression of FLT1 and its ligands in MLS cells.</p> <p>Methods</p> <p>HT1080 human fibrosarcoma cells were transiently transfected with <it>FUS-DDIT3</it>-GFP variant constructs and FLT1 expression was measured by quantitative real-time PCR. In addition, <it>FLT1</it>, <it>PGF, VEGFA and VEGFB </it>expression was measured in MLS/RCLS cell lines, MLS/RCLS tumors and in normal adiopocytes. We analyzed nine cases of MLS/RCLS and one cell line xenografted in mice for FLT1 protein expression using immunohistochemistry. MLS/RCLS cell lines were also analyzed for FLT1 by immunofluorescence and western blot. MLS/RCLS cell lines were additionally treated with FLT1 tyrosine kinase inhibitors and assayed for alterations in proliferation rate.</p> <p>Results</p> <p><it>FLT1 </it>expression was dramatically increased in transfected cells stably expressing FUS-DDIT3 and present at high levels in cell lines derived from MLS. The FLT1 protein showed a strong nuclear expression in cells of MLS tissue as well as in cultured MLS cells, which was confirmed by cellular fractionation. Tissue array analysis showed a nuclear expression of the FLT1 protein also in several other tumor and normal cell types including normal adipocytes. The FLT1 ligand coding gene <it>PGF </it>was highly expressed in cultured MLS cells compared to normal adipocytes while the other ligand genes <it>VEGFA </it>and <it>VEGFB </it>were expressed to lower levels. A more heterogeneous expression pattern of these genes were observed in tumor samples. No changes in proliferation rate of MLS cells were detected at concentrations for which the kinase inhibitors have shown specific inhibition of FLT1.</p> <p>Conclusions</p> <p>Our results imply that <it>FLT1 </it>is induced as an indirect downstream effect of FUS-DDIT3 expression in MLS. This could be a consequence of the ability of FUS-DDIT3 to hijack parts of normal adipose tissue development and reprogram primary cells to a liposarcoma-like phenotype. The findings of nuclear FLT1 protein and expression of corresponding ligands in MLS and normal tissues may have implications for tissue homeostasis and tumor development through auto- or intracrine signaling.</p

Voluntary self-poisoning as a cause of admission to a tertiary hospital internal medicine clinic in Piraeus, Greece within a year

BACKGROUND: Out of 1705 patients hospitalised for various reasons in the 3(rd) Internal Medicine Department of the Regional General Hospital of Nikaea, in Piraeus, 146(8,5%) persons were admitted for drug intoxication between November 1999 and November 2000. METHODS: On average, these persons [male 50(34,2%) – female 96(65,8%)] were admitted to the hospital within 3.7 hours after taking the drug. RESULTS: The drugs that were more frequently taken, alone or in combination with other drugs, were sedatives (67.1%), aspirins and analgesics (mainly paracetamol) (43.5%). 38.3% of patients had a mental illness history, 31.5% were in need of psychiatric help and 45.2% had made a previous suicide attempt. No death occurred during the above period and the outcome of the patients' health was normal. After mental state examination, the mental illnesses diagnosed were depression (20.96%), psychosis (15.32%), dysthymic disorder (16,2%), anxiety disorder (22.58%) and personality disorder (8.87%). CONCLUSIONS: Self-poisoning remains a crucial problem. The use of paracetamol and sedatives are particularly important in the population studied. Interpersonal psychiatric therapy may be a valuable treatment after people tried to poison themselves

Academic Performance and Behavioral Patterns

Identifying the factors that influence academic performance is an essential part of educational research. Previous studies have documented the importance of personality traits, class attendance, and social network structure. Because most of these analyses were based on a single behavioral aspect and/or small sample sizes, there is currently no quantification of the interplay of these factors. Here, we study the academic performance among a cohort of 538 undergraduate students forming a single, densely connected social network. Our work is based on data collected using smartphones, which the students used as their primary phones for two years. The availability of multi-channel data from a single population allows us to directly compare the explanatory power of individual and social characteristics. We find that the most informative indicators of performance are based on social ties and that network indicators result in better model performance than individual characteristics (including both personality and class attendance). We confirm earlier findings that class attendance is the most important predictor among individual characteristics. Finally, our results suggest the presence of strong homophily and/or peer effects among university students

IceCube - the next generation neutrino telescope at the South Pole

IceCube is a large neutrino telescope of the next generation to be constructed in the Antarctic Ice Sheet near the South Pole. We present the conceptual design and the sensitivity of the IceCube detector to predicted fluxes of neutrinos, both atmospheric and extra-terrestrial. A complete simulation of the detector design has been used to study the detector's capability to search for neutrinos from sources such as active galaxies, and gamma-ray bursts.Comment: 8 pages, to be published with the proceedings of the XXth International Conference on Neutrino Physics and Astrophysics, Munich 200

Course of serum amyloid A (SAA) plasma concentrations in horses undergoing surgery for injuries penetrating synovial structures, an observational clinical study

Abstract Background Injuries penetrating synovial structures are common in equine practice and often result in septic synovitis. Significantly increased plasma levels of serum amyloid A (SAA) have been found in various infectious conditions in horses including wounds and septic arthritis. Plasma SAA levels were found to decrease rapidly once the infectious stimulus was eliminated. The purpose of the current study was to investigate the usefulness of serial measurements of plasma SAA as a monitoring tool for the response to treatment of horses presented with injuries penetrating synovial structures. In the current study plasma SAA concentrations were measured every 48 hours (h) during the course of treatment. Results A total of 19 horses with a wound penetrating a synovial structure were included in the current study. Horses in Group 1 (n = 12) (injuries older than 24 h) only needed one surgical intervention. Patients in this group had significantly lower median plasma SAA levels (P = 0.001) between 48 h (median 776 mg/L) and 96 h (median 202 mg/L) after surgery. A significant decrease (P = 0.004) in plasma SAA levels was also observed between 96 h after surgery (median 270 mg/L) and 6 days (d) after surgery (median 3 mg/L). Four horses (Group 2) required more than one surgical intervention. In contrast to Group 1 patients in Group 2 had either very high initial plasma concentrations (3378 mg/L), an increase or persistently high concentrations of plasma SAA after the first surgery (median 2525 mg/L). A small group of patients (n = 3) (Group 3) were admitted less than 24 h after sustaining a wound. In this group low SAA values at admission (median 23 mg/L) and peak concentrations at 48 h after surgery (median 1016 mg/L) were observed followed by a decrease in plasma SAA concentration over time. Conclusions A decrease in plasma SAA concentrations between two consecutive time points could be associated with positive response to treatment in the current study. Therefore, serial measurements of plasma SAA could potentially be used as an additional inexpensive, quick and easy tool for monitoring the treatment response in otherwise healthy horses presented with injuries penetrating synovial structures. However further studies will be necessary to ascertain its clinical utility

Toward A Brain-Based Theory of Beauty

We wanted to learn whether activity in the same area(s) of the brain correlate with the experience of beauty derived from different sources. 21 subjects took part in a brain-scanning experiment using functional magnetic resonance imaging. Prior to the experiment, they viewed pictures of paintings and listened to musical excerpts, both of which they rated on a scale of 1-9, with 9 being the most beautiful. This allowed us to select three sets of stimuli-beautiful, indifferent and ugly-which subjects viewed and heard in the scanner, and rated at the end of each presentation. The results of a conjunction analysis of brain activity showed that, of the several areas that were active with each type of stimulus, only one cortical area, located in the medial orbito-frontal cortex (mOFC), was active during the experience of musical and visual beauty, with the activity produced by the experience of beauty derived from either source overlapping almost completely within it. The strength of activation in this part of the mOFC was proportional to the strength of the declared intensity of the experience of beauty. We conclude that, as far as activity in the brain is concerned, there is a faculty of beauty that is not dependent on the modality through which it is conveyed but which can be activated by at least two sources-musical and visual-and probably by other sources as well. This has led us to formulate a brain-based theory of beauty

A computational study of the heterogeneous synthesis of hydrazine on Co3Mo3N

Periodic and molecular density functional theory calculations have been applied to elucidate the associative mechanism for hydrazine and ammonia synthesis in the gas phase and hydrazine formation on Co3Mo3N. We find that there are two activation barriers for the associative gas phase mechanism with barriers of 730 and 658 kJ/mol, corresponding to a hydrogenation step from N2 to NNH2 and H2NNH2 to H3NNH3, respectively. The second step of the mechanism is barrierless and an important intermediate, NNH2, can also readily form on Co3Mo3N surfaces via the Eley–Rideal chemisorption of H2 on a pre-adsorbed N2 at nitrogen vacancies. Based on this intermediate a new heterogeneous mechanism for hydrazine synthesis is studied. The highest relative barrier for this heterogeneous catalysed process is 213 kJ/mol for Co3Mo3N containing nitrogen vacancies, clearly pointing towards a low-energy process for the synthesis of hydrazine via a heterogeneous catalysis route