Effective Spectral Function for Quasielastic Scattering on Nuclei

Spectral functions that are used in neutrino event generators to model quasielastic (QE) scattering from nuclear targets include Fermi gas, Local Thomas Fermi gas (LTF), Bodek-Ritchie Fermi gas with high momentum tail, and the Benhar-Fantoni two dimensional spectral function. We find that the $\nu$ dependence of predictions of these spectral functions for the QE differential cross sections (${d^2\sigma}/{dQ^2 d\nu}$) are in disagreement with the prediction of the $\psi'$ superscaling function which is extracted from fits to quasielastic electron scattering data on nuclear targets. It is known that spectral functions do not fully describe quasielastic scattering because they only model the initial state. Final state interactions distort the shape of the differential cross section at the peak and increase the cross section at the tails of the distribution. We show that the kinematic distributions predicted by the $\psi'$ superscaling formalism can be well described with a modified {\it {effective spectral function}} (ESF). By construction, models using ESF in combination with the transverse enhancement contribution correctly predict electron QE scattering data.Comment: 16 pages, 23 figures, submitted to Eur. Phy. J.

Gravitational Wave Hotspots: Ranking Potential Locations of Single-Source Gravitational Wave Emission

The steadily improving sensitivity of pulsar timing arrays (PTAs) suggests that gravitational waves (GWs) from supermassive black hole binary (SMBHB) systems in the nearby universe will be de- tectable sometime during the next decade. Currently, PTAs assume an equal probability of detection from every sky position, but as evidence grows for a non-isotropic distribution of sources, is there a most likely sky position for a detectable single source of GWs? In this paper, a collection of galactic catalogs is used to calculate various metrics related to the detectability of a single GW source resolv- able above a GW background, assuming that every galaxy has the same probability of containing a SMBHB. Our analyses of these data reveal small probabilities that one of these sources is currently in the PTA band, but as sensitivity is improved regions of consistent probability density are found in predictable locations, specifically around local galaxy clusters.Comment: 9 pages, 9 figures, accepted for submission in Ap

Antiquark nuggets as dark matter: New constraints and detection prospects

Current evidence for dark matter in the universe does not exclude heavy composite nuclear-density objects consisting of bound quarks or antiquarks over a significant range of masses. Here we analyze one such proposed scenario, which hypothesizes antiquark nuggets with a range of log10(B) = 24-30 with specific predictions for spectral emissivity via interactions with normal matter. We find that, if these objects make up the majority of the dark matter density in the solar neighborhood, their radiation efficiency in solids is marginally constrained, due to limits from the total geothermal energy budget of the Earth. At allowed radiation efficiencies, the number density of such objects can be constrained to be well below dark matter densities by existing radio data over a mass range currently not restricted by other methods.Comment: 6 pages, 3 figures, revised references; submitted to PR

Thermal degradation and isomerisation kinetics of triolein studied by infrared spectrometry and GC-MS combined with chemometrics

Triolein, a triglyceride containing oleic acid as the only acid moiety in the glyceride molecules has been isothermally treated at 280,300,and 325 degrees C in glass vials under nitrogen atmosphere. The products formed during the thermal treatment at each temperature have been analysed both by infrared spectrometry and GC-MS. The CC-MS analysis was performed after derivatisation of the fatty acids into their methyl esters (FAMEs). Chemometric tools were used in determining the concentrations of the main products namely triolein and trieaidin in the thermally treated mixtures. The concentration profiles of the trielaidin formed during thermal treatment at the above three temperatures were used in determining activation energy for the cis-trans isomerisation of triolein. The combined analysis reveals that the thermal treatment induces not only cis-trans isomerisation but also fission and fusion in the molecules. Furthermore, migration of the double bond in oleic and elaidic acids forming cis and trans isomers of the 18:1 acid was also observed. The heat-induced isomerisation in triolein follows a zeroth order reaction with an activation energy 41 +/- 5 kcal/mol. (c) 2008 Elsevier Ireland Ltd. All rights reserve

ANALISIS POTENSI LIKUIFAKSI TANAH BERDASARKAN DATA STANDART PENETRATION TEST (SPT) STUDI KASUS : DERMAGA BITUNG, SULAWESI UTARA

Salah satu dampak yang disebabkan oleh gempa bumi adalah fenomena hilangnya kekuatan lapisan tanah akibat getaran yang disebut dengan likuifaksi. Likuifaksi biasanya terjadi pada tanah pasir yang bersifat lepas (loose). Analisis ini bertujuan untuk mengetahui potensi terjadinya likuifaksi pada Dermaga Bitung, Sulawesi Utara. Analisis potensi likuifaksi dilakukan dengan menggunakan metode yang diusulkan oleh Seed dan Idriss (1981), yaitu pertama mengumpulkan data pengujian tanah SPT di lokasi tersebut, serta melihat data percepatan gempa di lokasi tersebut. berdasarkan data tersebut kemudian dihitung nilai Cyclic Stress Ratio (CSR) yang merupakan nilai perbandingan antara tegangan geser rata-rata yang diakibatkan oleh gempa dengan tegangan vertikal efektif di setiap lapisan serta nilai Cyclic Resistance Ratio (CRR) yaitu besarnya ketahanan tanah terhadap likuifaksi. Dari nilai-nilai tersebut ditarik satu angka keamanan yang menentukan apakah lapisan tanah yang ditinjau itu berpotensi terjadi likuifaksi atau tidak. Berdasarkan analisis perhitungan yang dilakukan melalui dua titik hasil pengujian tanah yaitu titik bor BH-01 dan titik bor BH-02, dapat disimpulkan bahwa kondisi tanah di Dermaga Bitung, Sulawesi Utara tidak memiliki lapisan tanah yang berpotensi terjadi likuifaksi. Kata kunci : Gempa bumi, Likuifaksi, Cyclic Stress Ratio, Cyclic Resistance Rati

Do American Dippers Obtain a Survival Benefit from Altitudinal Migration?

Studies of partial migrants provide an opportunity to assess the cost and benefits of migration. Previous work has demonstrated that sedentary American dippers (residents) have higher annual productivity than altitudinal migrants that move to higher elevations to breed. Here we use a ten-year (30 period) mark-recapture dataset to evaluate whether migrants offset their lower productivity with higher survival during the migration-breeding period when they occupy different habitat, or early and late-winter periods when they coexist with residents. Mark-recapture models provide no evidence that apparent monthly survival of migrants is higher than that of residents at any time of the year. The best-supported model suggests that monthly survival is higher in the migration-breeding period than winter periods. Another well-supported model suggested that residency conferred a survival benefit, and annual apparent survival (calculated from model weighted monthly apparent survival estimates using the Delta method) of residents (0.511 ± 0.038SE) was slightly higher than that of migrants (0.487 ± 0.032). Winter survival of American dippers was influenced by environmental conditions; monthly apparent survival increased as maximum daily flow rates increased and declined as winter temperatures became colder. However, we found no evidence that environmental conditions altered differences in winter survival of residents and migrants. Since migratory American dippers have lower productivity and slightly lower survival than residents our data suggests that partial migration is likely an outcome of competition for limited nest sites at low elevations, with less competitive individuals being forced to migrate to higher elevations in order to breed

Q^2 Evolution of Generalized Baldin Sum Rule for the Proton

The generalized Baldin sum rule for virtual photon scattering, the unpolarized analogy of the generalized Gerasimov-Drell-Hearn integral, provides an important way to investigate the transition between perturbative QCD and hadronic descriptions of nucleon structure. This sum rule requires integration of the nucleon structure function F_1, which until recently had not been measured at low Q^2 and large x, i.e. in the nucleon resonance region. This work uses new data from inclusive electron-proton scattering in the resonance region obtained at Jefferson Lab, in combination with SLAC deep inelastic scattering data, to present first precision measurements of the generalized Baldin integral for the proton in the Q^2 range of 0.3 to 4.0 GeV^2.Comment: 4 pages, 3 figures, one table; text added, one figure replace

Global Analysis of Data on the Proton Structure Function g1 and Extraction of its Moments

Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g1 in the range 0.17 < Q2 < 30 (GeV/c)**2. We compute for the first time low-order moments of g1 and study their evolution from small to large values of Q2. The analysis includes the latest data on both the unpolarized inclusive cross sections and the ratio R = sigmaL / sigmaT from Jefferson Lab, as well as a new model for the transverse asymmetry A2 in the resonance region. The contributions of both leading and higher twists are extracted, taking into account effects from radiative corrections beyond the next-to-leading order by means of soft-gluon resummation techniques. The leading twist is determined with remarkably good accuracy and is compared with the predictions obtained using various polarized parton distribution sets available in the literature. The contribution of higher twists to the g1 moments is found to be significantly larger than in the case of the unpolarized structure function F2.Comment: 18 pages, 13 figures, to appear in Phys. Rev.

Mutant Prevention Concentrations of Some Aminoglycoside Antibiotics for Fecal Isolates of Escherichia coli under different Growth Temperatures

For optimal efficacy, an antibiotic must achieve and sustain at the site of infection, a concentration that can inhibit growth of the bacteria. However, a bacterial infection may contain subpopulations of mutant variants with reduced susceptibility to the antimicrobial agent. There is a great need to periodically evaluate the mutant prevention concentration (MPC) of antibiotic to provide a basis for altering dosing regimens such that the growth of resistant organisms could be curtailed. To evaluate the mutant prevention concentrations (MPCs) of streptomycin, gentamicin and amikacin for fecal Escherichia coli isolates under different growth temperatures and determine the extent of recovery of resistant mutants at such temperatures. Fifty (50) isolates of E. coli were isolated from stools of patients attending Nasarawa State University Keffi Health Centre in Keffi, Nigeria and identified using standard protocol. Antibiotic minimum inhibitory concentrations (MICs) were determined using macro-broth dilution method of the Clinical and Laboratory Standards Institute (CLSI) with incubation for 24 h at 37°C and 41°C. MIC for 50% (MIC50) and 90% (MIC90) of isolates were then generated from the plot of cumulative frequency curve. MPCs were measured by spreading a series of agar plates containing known aminoglycoside concentrations with approximately 1010 CFU of E. coli culture and incubated for 48 h at 37°C and 41°C. The lowest aminoglycoside concentration that prevented the growth of resistant colonies was taken as the MPC. MPCs for 50% (MPC50) and 90% (MPC90) of isolates were then generated from the plot of cumulative frequency of the MPCs obtained. MPC/MIC ratios for 50% (MPC50/MIC50) and 90% (MPC90/MIC90) of isolates were also determined. Bacteria surviving (persisting) at MPC were isolated and quantified after 48 h. Statistical analyses of data were done by one-way Analysis of Variance (ANOVA). For each of the drugs, MPC50 and MPC50/MIC50 were the same at both 37°C and 41°C. MPC50 values were: streptomycin (44.2 ?g/ml [?32.0 ?g/ml]); gentamicin (44.2 ?g/ml [?32.0 ?g/ml]); and amikacin (37.4 ?g/ml [?32.0 ?g/ml]); and MPC50/MIC50 ratios for each drug at both temperatures were ? 3. MPC90 and MPC90/MIC90 were the same for each drug at both 37°C and 41°C. MPC90 values were: streptomycin (253.2 ?g/ml [?256.0 ?g/ml]), gentamicin (209.0 ?g/ml [?256.0 ?g/ml]), and amikacin (128.0 ?g/ml); and MPC90/MIC90 ratios for each drug at both temperatures were ? 4. Mutant recoveries at the MPCs of the drugs for 50% of the isolates were significantly (P &lt; 0.05) different both at 37°C (P = 0.0089) and 41°C (P = 0.0011). However, mutant recoveries at the MPCs of the drugs for 90% the isolates were insignificantly (P &gt;0.05) different at 37°C (P = 0.0055) but significantly (P &gt; 0.005) different at 41°C (P = 0.0080). Whether at normal body temperature or at a higher body temperature usually obtained during fever, E. coli selects and enrich for resistant mutants less easily against streptomycin than gentamicin or amikacin. The extent of recovery of mutants however, is higher at the higher temperature, justifying the common practice of administering high dosage of antimicrobial agent at high body temperature during therapy of bacterial disease. Keywords: Mutant Prevention Concentration, Escherichia coli, Aminoglycosid