3,039 research outputs found

    Determination and Correlation of Anticardiolipin Antibody with High Sensitivity C- reactive Proteins and its Role in Predicting Short Term Outcome in Patients with Acute Coronary Syndrome

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    Anticardiolipin antibody (aCL) is considered to be an independent risk factor while high sensitivity C reactive protein (hsCRP) is an established marker for coronary artery disease. This study was conducted to determine levels of aCL antibodies and hsCRP, their correlation and role in predicting recurrence of events in patients presenting with Acute Coronary Syndrome (ACS). Sixty patients admitted with Acute Coronary Syndrome were followed up for 7 days or until discharge. Patients were classified into two groups as those having experienced an ischemic event needing intervention within 7 days (Group I) and other having an event free recovery (Group II). aCL antibody and hsCRP levels were estimated and compared in these two groups. Twenty age and sex matched disease free persons served as controls. The levels of aCL were significantly higher in patients with ACS as compared to the controls (p=0.020). However the levels of aCL in Group I (13.39±9.46 GPL-U/ml) and Group II (13.51±9.93 GPL-U/ml) were not significantly different (p =0.838). The mean hsCRP levels were higher in cases with an event (23.30±10.68 mg/dl) than in cases without an event (20.60±11.45mg/dl) though it was not significant statistically (p=0.389). aCL and CRP were not found to be significantly correlated in causing the recurrence of events(p=0.178). Therefore anticardiolipin antibody is an independent risk factor which could be implicated in the pathogenesis of ACS. However it is not significantly associated with recurrence of short-term events in patients with ACS. Also, aCL antibody does not have significant correlation with hSCRP in causing recurrence of events in the patients of acute coronary syndrome

    Coronal Emission Measures and Abundances for Moderately Active K Dwarfs Observed by Chandra

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    We have used Chandra to resolve the nearby 70 Oph (K0 V+K5 V) and 36 Oph (K1 V+K1 V) binary systems for the first time in X-rays. The LETG/HRC-S spectra of all four of these stars are presented and compared with an archival LETG spectrum of another moderately active K dwarf, Epsilon Eri. Coronal densities are estimated from O VII line ratios and emission measure distributions are computed for all five of these stars. We see no substantial differences in coronal density or temperature among these stars, which is not surprising considering that they are all early K dwarfs with similar activity levels. However, we do see significant differences in coronal abundance patterns. Coronal abundance anomalies are generally associated with the first ionization potential (FIP) of the elements. On the Sun, low-FIP elements are enhanced in the corona relative to high-FIP elements, the so-called "FIP effect." Different levels of FIP effect are seen for our stellar sample, ranging from 70 Oph A, which shows a prominent solar-like FIP effect, to 70 Oph B, which has no FIP bias at all or possibly even a weak inverse FIP effect. The strong abundance difference exhibited by the two 70 Oph stars is unexpected considering how similar these stars are in all other respects (spectral type, age, rotation period, X-ray flux). It will be difficult for any theoretical explanation for the FIP effect to explain how two stars so similar in all other respects can have coronae with different degrees of FIP bias. Finally, for the stars in our sample exhibiting a FIP effect, a curious difference from the solar version of the phenomenon is that the data seem to be more consistent with the high-FIP elements being depleted in the corona rather than a with a low-FIP enhancementComment: 35 pages, 8 figures, AASTEX v5.0 plus EPSF extensions in mkfig.sty; accepted by Ap

    In Vitro Propagation and Conservation of Inula Racemosa Hook. F. an Endangered Medicinal Plant of Temperate Origin

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    Inula racemosa is an endangered medicinal plant. It is commonly known as Pushkarmool, Pushkar and Manu. The great sage Charaka has characterized it as Hikka magrahana (stops hiccups) and Savasahara (helpful in asthma). Also, he has cited it as the best medicament for pleurisy along with cough and asthma (http://enwikipedia.org/wiki/charaka-samhita). Due to the fragile nature of its habitat and exploitation due to its commercial medicinal properties, the species are facing the onslaught of indiscriminate over-exploitation. So far, this plant has not got the required attention from researchers, hence, except for a few efforts, not much work has been done for its cultivation and conservation. Plant tissue culture offers an attractive and quick method for its multiplication and further conservation. In the present investigation, effective procedures for micropropagation and in vitro conservation by vitrification were developed. In vitro propagation using aseptically grown seedlings and in vitro conservation via vitrification were standardized. The in vitro conserved material could be retrieved and multiplied normally on MS (Murashige and Skoog, 1962) medium fortified with 1.00 mg l-1BA (benzyl adenine) which has been recorded as the best performing medium for in vitro shoot multiplication. The conserved shoots showed normal in vitro propagation and after retrieval from vitrification, platelets were hardened and successfully established in the experimental fields under Nauni (Solan, HP) conditions at an elevation of around 1275 meters above mean sea level

    Optimized coupling of cold atoms into a fiber using a blue-detuned hollow-beam funnel

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    We theoretically investigate the process of coupling cold atoms into the core of a hollow-core photonic-crystal optical fiber using a blue-detuned Laguerre-Gaussian beam. In contrast to the use of a red-detuned Gaussian beam to couple the atoms, the blue-detuned hollow-beam can confine cold atoms to the darkest regions of the beam thereby minimizing shifts in the internal states and making the guide highly robust to heating effects. This single optical beam is used as both a funnel and guide to maximize the number of atoms into the fiber. In the proposed experiment, Rb atoms are loaded into a magneto-optical trap (MOT) above a vertically-oriented optical fiber. We observe a gravito-optical trapping effect for atoms with high orbital momentum around the trap axis, which prevents atoms from coupling to the fiber: these atoms lack the kinetic energy to escape the potential and are thus trapped in the laser funnel indefinitely. We find that by reducing the dipolar force to the point at which the trapping effect just vanishes, it is possible to optimize the coupling of atoms into the fiber. Our simulations predict that by using a low-power (2.5 mW) and far-detuned (300 GHz) Laguerre-Gaussian beam with a 20-{\mu}m radius core hollow-fiber it is possible to couple 11% of the atoms from a MOT 9 mm away from the fiber. When MOT is positioned further away, coupling efficiencies over 50% can be achieved with larger core fibers.Comment: 11 pages, 12 figures, 1 tabl

    X-ray Variability in the Young Massive Triple theta2 Ori A

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    Massive stars rarely show intrinsic X-ray variability. The only O-stars credited to be intrinsically variable are theta1 Ori C due to effects from magnetic confinement of its wind, and theta2 Ori A suspected of similar activity. Early Chandra observations have shown that the most massive star system in the Orion Trapezium Cluster, theta2 Ori A, shows rapid variability on time scales of hours. We determine X-ray fluxes and find that the star shows very strong variability over the last 5 years. We observed a second large X-ray outburst in November 2004 with the high resolution transmission grating spectrometer on-board Chandra. In the low state X-ray emissivities indicate temperatures well above 25 MK. In the high state we find an extended emissivity distribution with high emissivities in the range from 3 MK to over 100 MK. The outburst event in stellar terms is one of the most powerful ever observed and the most energetic one in the ONC with a lower total energy limit of 1.5x10^37 ergs. The line diagnostics show that under the assumption that the line emitting regions in the low states are as close as within 1 -- 2 stellar radii from the O-star's photosphere, whereas the hard states suggest a distance of 3 -- 5 stellar radii. The two outbursts are very close to the periastron passage of the stars. We argue that the high X-ray states are possibly the result of reconnection events from magnetic interactions of the primary and secondary stars of the spectroscopic binary. Effects from wind collisions seem unlikely for this system. The low state emissivity and R-ratios strengthen the predicament that the X-ray emission is enhanced by magnetic confinement of the primary wind. We also detect Fe fluorescence indicative of the existence of substantial amounts of neutral Fe in the vicinity of the X-ray emission.Comment: 11 pages, 8 figures, accepted for publication in The Astrophysical Main Journa

    Soft X-ray emission lines of Fe XV in solar flare observations and the Chandra spectrum of Capella

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    Recent calculations of atomic data for Fe XV have been used to generate theoretical line ratios involving n = 3-4 transitions in the soft X-ray spectral region (52-83 A), for a wide range of electron temperatures and densities applicable to solar and stellar coronal plasmas. A comparison of these with solar flare observations from a rocket-borne spectrograph (XSST) reveals generally good agreement between theory and experiment. In particular, the 82.76 A emission line in the XSST spectrum is identified, for the first time to our knowledge in an astrophysical source. Most of the Fe XV transitions which are blended have had the species responsible clearly identified, although there remain a few instances where this has not been possible. The line ratio calculations are also compared with a co-added spectrum of Capella obtained with the Chandra satellite, which is probably the highest signal-to-noise observation achieved for a stellar source in the 25-175 A soft X-ray region. Good agreement is found between theory and experiment, indicating that the Fe XV lines are reliably detected in Chandra spectra, and hence may be employed as diagnostics to determine the temperature and/or density of the emitting plasma. However the line blending in the Chandra data is such that individual emission lines are difficult to measure accurately, and fluxes may only be reliably determined via detailed profile fitting of the observations. The co-added Capella spectrum is made available to hopefully encourage further exploration of the soft X-ray region in astronomical sources.Comment: 27 pages, 10 figures, Astrophysical Journal, in pres

    Rare events, escape rates and quasistationarity: some exact formulae

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    We present a common framework to study decay and exchanges rates in a wide class of dynamical systems. Several applications, ranging form the metric theory of continuons fractions and the Shannon capacity of contrained systems to the decay rate of metastable states, are given
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