Partial Decay Widths of Negative Parity Baryons in the 1/Nc Expansion

The partial decay widths of lowest lying negative parity baryons belonging to the 70-plet of SU(6) are analyzed in the framework of the 1/Nc expansion The channels considered are those with single pseudo-scalar meson emission. The analysis is carried out to sub-leading order in 1/Nc and to first order in SU(3) symmetry breaking. Conclusions about the magnitude of SU(3) breaking effects along with predictions for some unknown or poorly determined partial decay widths of known resonances are obtained.Comment: 35 pages, 20 table

The role of Serum NT-proBNP for predicting left ventricular systolic dysfunction in hospitalized patients in Sri Lanka

Background/aimsOnly a few studies have addressed the role of NT-proBNP in identifying Left Ventricular Systolic Dysfunction (LVSD) in South Asian populations. Therefore, the current study was aimed at assessing the use of serum NT-proBNP in predicting LVSD in a hospitalized population in Sri Lanka.MethodsA random sample of 278 individuals referred for echocardiography at a major Teaching Hospital consented for venous blood samples to be collected for serum NT-proBNP assay by sandwich ELISA. Based on the ejection fraction (LVEF) and fractional shortening (FS), participants were differentiated as LVSD (LVEF<50%, FS≤ 29%) and non-LVSD individuals (LVEF>60%). According to inclusion/exclusion criteria, the final study sample consisted of 100 LVSD patients and 41 non-LVSD individuals.ResultsThe mean ages of the LVSD and non-LVSD groups were 69.1 (±6.2 years) and 71.4 (±2.4 years) (p=0.066) respectively. The median NT-proBNP value (with IQR) among LVSD patients (528.2 pg/mL,355.2–924.2) was comparatively higher than that of non-LVSD individuals (207.3 pg/mL,177.5–343.0). Strong correlations of NT-proBNP level with LVEF (Spearman rho= -0.84, p<0.001) and FS (rho= -0.81, p<0.001) suggested that serum NT-proBNP concentration increases in parallel to deteriorating left ventricular functions. The AUROC of serum NT-proBNP for differentiating LVSD was 0.859 (95% CI:0.79 – 0.92) and the optimal cut-off level for predicting LVSD was 265pg/mL, with 90% sensitivity and 70% specificity.ConclusionCurrent Sri Lankan study revealed a considerable correlation of serum NT-proBNP level with LVSD and utilizing such an assay for screening will facilitate adequate evidence to rule-out LVSD among high-risk residents

FACTORS AFFECTING THE SWELLING PRESSURE MEASURED BY THE OEDEMETER METHOD

ABSTRACT: Expansive soils are common in arid and semi-arid climate regions of the world and cause severe problems on civil engineering structures. The Swelling potential of the expansive soil mainly depends upon the properties of soil and environmental factors, and stress conditions. Swelling pressure is a key parameter used in designing structures in and on expansive soil. The swelling pressure of soil is measured in the laboratory using a representative soil samples. The size and the surface friction of the sample ring used in the swelling pressure test have effects on the measured swelling pressure and they have not properly been investigated. In this study, a series of constant volume swelling tests were conducted using an automated consolidation-swell apparatus to evaluate the effect of sample ring size, ring friction, initial dry density, and initial moisture content (IMC). Test results indicate an exponential growing trend of swelling pressure when the dry density is increased. Similarly, high swell pressures are achieved when the IMC is increased for the same dry density. A higher swelling pressure was measured when the friction of the specimen ring was reduced. The measured swelling pressure increases with increasing the height of the sampling ring and it decreases when the ring diameter is increased. Therefore, it is recommended to use a standard sample ring reducing inside wall friction using lubricants when measuring the swelling pressure in the laboratory. Further, the sample ring size, initial density and initial moisture content of soil should be given when reporting swelling pressure of soil

Thermal stability and optoelectronic behavior of polyaniline/GNP (graphene nanoplatelets) nanocomposites

Polyaniline and graphene nanoplatelets (PANI-GNP) nanocomposites are synthesized by in situ oxidative polymerization of polyaniline using an oxidizing agent, ammonium peroxy disulphate (APS). The mass of GNP in the nanocomposites varied by 5, 10, and 15 wt% compared to PANI. The synthesized polyaniline coated graphene nanoplatelets (PANI-GNP) nanocomposites are chemically characterized and using Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, Scanning electron microscopy (SEM), UV-Vis spectroscopy, and X-ray diffraction analysis (XRD). FTIR and Raman spectroscopy analysis confirmed the uniform coating of polyaniline on GNP. The SEM micrograph and XRD pattern demonstrate the polymerization quality and crystallization degree of samples. UV-Vis analysis showed a decrease in the bandgap of polyaniline, which confirms that nanocomposites are more suitable for optoelectronic application because of variation in the bandgap. TGA analysis showed the thermal stability of PANI is increased with the increased mass of GNP. This study suggests the potential of GNP as a filler for efficient modification in the morphological, electrical, optical, and thermal properties of PANI.Comment: 13 pages, with 8 figures and one tabl

Molecular epidemiology of leptospirosis in western and southern provinces in Sri Lanka

Objective:The present study investigated the molecular epidemiology of leptospirosis in selected provinces in Sri LankaMethods: A prospective study was carried out between January 2013 to 2014. Adult patients with clinically suspected leptospirosis admitted to the medical wards at selected hospital were included. A whole blood sample was collected and DNA was extracted. leptospira IgM was detected using an immunochromatographic assay. PCR was done using fla B primers followed by RFLP using Hind III and Hae III. Nested PCR was performed using rrs primers which amplifies 16S rRNA gene. Amplicons resulting from rrs PCR were purified and subjected to bidirectional DNA sequencing and phylogenic analyses were conducted.Results: Out of the 168 clinically suspected leptospirosis cases 84 (50%) were IgM positive and 13 (7.7 %) were positive with Fla B PCR while 14 were rrs PCR positive. Based on sequence analysis, Leptospira interrogans (11/14, 79%) was the most common cause of disease followed by Leptospira borgpetersenii (2/14,14%) and Leptospira kirschneri (1/14,7%). Renal failure was the most common complication (4/11, 36%) associated with L. interrogans followed by myocarditis(2/11,18%). Leptospira borgpetersenii was associated with myocarditis and liver failure while Leptospira kirschneri was associated with acute renal failure. RFLP Hind 111 digestions could not differentiate between L. interrogans strains Canicola, Icterrohaemorrgiae and Pyrogenes while Hae 111 digestion showed better discrimination.Conclusions: L. interrogans was the predominant circulating strain in western and southern provinces in 2013 in Sri Lanka. The current data will contribute to determining molecular epidemiological diversity of circulating leptospira in Sri Lank

Observation of the Helium 7 Lambda hypernucleus by the (e,e'K+) reaction

An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 Lambda, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The he 7 Lambda binding energy supplies the last missing information of the A=7, T=1 hypernuclear iso-triplet, providing a new input for the charge symmetry breaking (CSB) effect of \Lambda N potential.Comment: 5 pages, 4 figures, submitted to PR

Measurements of Non-Singlet Moments of the Nucleon Structure Functions and Comparison to Predictions from Lattice QCD for Q2=4Q^2 = 4 GeV2\rm GeV^2

We present extractions of the nucleon non-singlet moments utilizing new precision data on the deuteron $F_2$ structure function at large Bjorken-$x$ determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world data sets on the proton and deuteron at lower $x$ measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the $x$ range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high $x$ data. Moreover, recent exciting developments in Lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach which first calculates the quark distributions directly before determining moments