16,769 research outputs found

    NRQCD results on the MILC extra coarse ensemble

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    We present preliminary results using NRQCD to describe heavy quarks on the MILC 2+1 flavour dynamical extra coarse ensemble. We calculate the spectra of low lying states in bottomonium to complement earlier results on the finer MILC ensembles. We then exploit the coarseness of the lattices to calculate charm propagators using NRQCD. These are used to examine the charmonium spectrum and to calclate the mass of the BcB_c using NRQCD. Finally we look breifly at the BdB_d and BsB_s systems using the imporoved staggered formalism to describe the light valence quarks.Comment: 6 pages, Talk presented at Lattice 2005 (Heavy Quarks), Dublin, 25-30 July 200

    Scale-Dependent Price Fluctuations for the Indian Stock Market

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    Classic studies of the probability density of price fluctuations gg for stocks and foreign exchanges of several highly developed economies have been interpreted using a {\it power-law} probability density function P(g)g(α+1)P(g) \sim g^{-(\alpha+1)} with exponent values α>2\alpha > 2, which are outside the L\'evy-stable regime 0<α<20 < \alpha < 2. To test the universality of this relationship for less highly developed economies, we analyze daily returns for the period Nov. 1994--June 2002 for the 49 largest stocks of the National Stock Exchange which has the highest volume of trade in India. We find that P(g)P(g) decays as an {\it exponential} function P(g)exp(βg)P(g) \sim \exp(-\beta g) with a characteristic decay scales β=1.51±0.05\beta = 1.51 \pm 0.05 for the negative tail and β=1.34±0.04\beta = 1.34 \pm 0.04 for the positive tail, which is significantly different from that observed for developed economies. Thus we conclude that the Indian stock market may belong to a universality class that differs from those of developed countries analyzed previously.Comment: 7 pages, 8 figure

    Secondary prevention of stroke: Using the experiences of patients and carers to inform the development of an educational resource

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    Copyright @ The Author 2008. This article is available open access through the publisher’s website at the link below.Background. Patients who have had one stroke are at increased risk of another. Secondary prevention strategies that address medical risk factors and promote healthy lifestyles can reduce the risk. However, concordance with secondary prevention strategies is poor and there has been little research into patient and carer views. Objectives. To explore the experiences of patients and carers of receiving secondary prevention advice and use these to inform the development of an educational resource. Methods. A total of 38 participants (25 patients and 13 carers) took part in the study which used an action research approach. Focus groups and interviews were undertaken with patients and carers who had been discharged from hospital after stroke (between 3 and 24 months previously). Framework analysis was used to examine the data and elicit action points to develop an educational resource. Results. Participants’ main concern was their desire for early access to information. They commented on their priorities for what information or support they needed, the difficulty of absorbing complex information whilst still an in-patient and how health professionals’ use of language was often a barrier to understanding. They discussed the facilitators and barriers to making lifestyle changes. The educational resource was developed to include specific advice for medical and lifestyle risk factors and an individual action plan. Conclusion. An educational resource for secondary prevention of stroke was developed using a participatory methodology. Our findings suggest that this resource is best delivered in a one-to-one manner, but further work is needed to identify its potential utility.Peninsula Primary Care Research Networ

    A Newly Found Kansas Legal Broadside

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    This is the published version

    Striped Magnetic Ground State of the Kagome Lattice in Fe4Si2Sn7O16

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    We have experimentally identified a new magnetic ground state for the kagome lattice, in the perfectly hexagonal Fe2+ (3d6, S = 2) compound Fe4Si2Sn7O16. Representational symmetry analysis of neutron diffraction data shows that below T_N = 3.5 K, the spins on 2/3 of the magnetic ions order into canted antiferromagnetic chains, separated by the remaining 1/3 which are geometrically frustrated and show no long-range order down to at least T = 0.1 K. Moessbauer spectroscopy confirms that there is no static order on the latter 1/3 of the magnetic ions - i.e., they are in a liquid-like rather than a frozen state - down to at least 1.65 K. A heavily Mn-doped sample Fe1.45Mn2.55Si2Sn7O16 has the same magnetic structure. Although the propagation vector q = (0, 1/2 , 1/2 ) breaks hexagonal symmetry, we see no evidence for magnetostriction in the form of a lattice distortion within the resolution of our data. We discuss the relationship to partially frustrated magnetic order on the pyrochlore lattice of Gd2Ti2O7, and to theoretical models that predict symmetry breaking ground states for perfect kagome lattices.Comment: 5 pages, 5 figure

    Effect of Absence of Developing Grain on Carbohydrate Content and Senescence of Maize Leaves

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    Small Intensely Fluorescent Cells in Culture: Role of Glucocorticoids and Growth Factors in Their Development and lnterconversions with other Neural Crest Derivatives

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    The neural crest gives rise to a number of adrenergic derivatives, including sympathetic neurons and adrenal chromaffin cells, which contain catecholamines (CAs) but differ in other morphological and functional characteristics. Small intensely fluorescent (SIF) cells, which exist primarily as a minority cell population in autonomic ganglia, are a third cell type in the sympathoadrenal branch of the neural crest lineage. In some respects these cells appear intermediate in phenotype between sympathetic neurons and adrenal chromaffin cells. We established pure dissociated cell cultures of SIF cells from rat superior cervical ganglia (SCG) and used these to study the role of environmental factors in SIF cell development and the relationship of these cells to the other cell types of the sympathoadrenal lineage. When cells from neonatal rat SCG were grown for 3 weeks in the presence of glucocorticoid and in the absence of nerve growth factor (NGF), pure cultures of SIF cells developed. The properties of the cells included (i) small cell size and the occasional presence of short neurites, (ii) intense CA histofluorescence and immunoreactivity for CA synthetic enzymes, (iii) synthesis and storage of CA from radioactive precursors, and (iv) characteristic ultrastructure. The concentration of the glucocorticoid and the presence or absence of non-neuronal cell factors influenced which types of SIF cells developed. In micromolar glucocorticoid most of the cells resembled adrenal chromaffin or type II SIF cells: they displayed immunohistochemically detectable phenylethanolamine-N-methyltransferase (PNMT), synthesized and stored epinephrine, and contained large granular vesicles (100 to 300 nm). When SCG cells were grown in 10(-8) M hormone, many fewer SIF cells developed and a higher percentage of these lacked PNMT immunoreactivity, had neurites, and contained vesicles of smaller mean diameter (70 to 130 nm), similar to those of type I SIF cells in vivo. In the presence of conditioned medium (medium conditioned by non- neuronal cells) as well as glucocorticoid, virtually all of the cells morphologically resembled type I SIF cells. In the absence of glucocorticoid, no SIF cells were ever observed after 3 weeks in culture. By following the development of CA histofluorescence and SIF cell ultrastructure in the cultures over time, we demonstrated that SIF cells were not present in large numbers in these cultures immediately after plating, but were induced from an apparently undifferentiated precursor by the hormonal environment, whereas most of the principal neurons died

    Quantifying engineered nanomaterial toxicity: comparison of common cytotoxicity and gene expression measurements

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    BACKGROUND: When evaluating the toxicity of engineered nanomaterials (ENMS) it is important to use multiple bioassays based on different mechanisms of action. In this regard we evaluated the use of gene expression and common cytotoxicity measurements using as test materials, two selected nanoparticles with known differences in toxicity, 5 nm mercaptoundecanoic acid (MUA)-capped InP and CdSe quantum dots (QDs). We tested the effects of these QDs at concentrations ranging from 0.5 to 160 µg/mL on cultured normal human bronchial epithelial (NHBE) cells using four common cytotoxicity assays: the dichlorofluorescein assay for reactive oxygen species (ROS), the lactate dehydrogenase assay for membrane viability (LDH), the mitochondrial dehydrogenase assay for mitochondrial function, and the Comet assay for DNA strand breaks. RESULTS: The cytotoxicity assays showed similar trends when exposed to nanoparticles for 24 h at 80 µg/mL with a threefold increase in ROS with exposure to CdSe QDs compared to an insignificant change in ROS levels after exposure to InP QDs, a twofold increase in the LDH necrosis assay in NHBE cells with exposure to CdSe QDs compared to a 50% decrease for InP QDs, a 60% decrease in the mitochondrial function assay upon exposure to CdSe QDs compared to a minimal increase in the case of InP and significant DNA strand breaks after exposure to CdSe QDs compared to no significant DNA strand breaks with InP. High-throughput quantitative real-time polymerase chain reaction (qRT-PCR) data for cells exposed for 6 h at a concentration of 80 µg/mL were consistent with the cytotoxicity assays showing major differences in DNA damage, DNA repair and mitochondrial function gene regulatory responses to the CdSe and InP QDs. The BRCA2, CYP1A1, CYP1B1, CDK1, SFN and VEGFA genes were observed to be upregulated specifically from increased CdSe exposure and suggests their possible utility as biomarkers for toxicity. CONCLUSIONS: This study can serve as a model for comparing traditional cytotoxicity assays and gene expression measurements and to determine candidate biomarkers for assessing the biocompatibility of ENMs.1R01GM84702-01 - National Institute of General Medical Science
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