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Sample records for hexoses variables studied

  1. Fsy1, the sole hexose-proton transporter characterized in Saccharomyces yeasts, exhibits a variable fructose:H(+) stoichiometry.

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    Anjos, Jorge; Rodrigues de Sousa, Helena; Roca, Christophe; Cássio, Fernanda; Luttik, Marijke; Pronk, Jack T; Salema-Oom, Madalena; Gonçalves, Paula

    2013-02-01

    In the model yeast Saccharomyces cerevisiae, hexose uptake is mediated exclusively by a family of facilitators (Hxt, hexose transporters). Some other Saccharomyces species (e.g. Saccharomyces bayanus and Saccharomyces pastorianus) possess, in addition, a specific fructose transporter (Fsy1, fructose symporter) that has been previously described to function as a proton symporter. In the present work, we compared growth of a yeast strain in which FSY1 occurs naturally in anaerobic, fructose- and glucose-limited chemostat cultures. Especially at low specific growth rates, fructose-proton symport was shown to have a strong impact on the biomass yield on sugar. We subsequently employed energized hybrid plasma membrane vesicles to confirm previous observations concerning the mode of operation and specificity of Fsy1 mediated transport. Surprisingly, these experiments suggested that the carrier exhibits an unusual fructose:H(+) stoichiometry of 1:2. This energetically expensive mode of operation was also found consistently in vivo, in shake flask and in chemostat cultures, and both when Fsy1 is the sole transporter and when the Hxt carriers are present. However, it is observed only when Fsy1 is operating at higher glycolytic fluxes, a situation that is normally prevented by downregulation of the gene. Taken together, our results suggest the possibility that fructose symport with more than one proton may constitute an energetically unfavorable mode of operation of the Fsy1 transporter that, in growing cultures, is prevented by transcriptional regulation.

  2. Automated identification of protein-ligand interaction features using Inductive Logic Programming: a hexose binding case study

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    A Santos Jose C

    2012-07-01

    Full Text Available Abstract Background There is a need for automated methods to learn general features of the interactions of a ligand class with its diverse set of protein receptors. An appropriate machine learning approach is Inductive Logic Programming (ILP, which automatically generates comprehensible rules in addition to prediction. The development of ILP systems which can learn rules of the complexity required for studies on protein structure remains a challenge. In this work we use a new ILP system, ProGolem, and demonstrate its performance on learning features of hexose-protein interactions. Results The rules induced by ProGolem detect interactions mediated by aromatics and by planar-polar residues, in addition to less common features such as the aromatic sandwich. The rules also reveal a previously unreported dependency for residues cys and leu. They also specify interactions involving aromatic and hydrogen bonding residues. This paper shows that Inductive Logic Programming implemented in ProGolem can derive rules giving structural features of protein/ligand interactions. Several of these rules are consistent with descriptions in the literature. Conclusions In addition to confirming literature results, ProGolem’s model has a 10-fold cross-validated predictive accuracy that is superior, at the 95% confidence level, to another ILP system previously used to study protein/hexose interactions and is comparable with state-of-the-art statistical learners.

  3. Advances in the enzymatic production of L-hexoses.

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    Chen, Ziwei; Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

    2016-08-01

    Rare sugars have recently drawn attention because of their potential applications and huge market demands in the food and pharmaceutical industries. All L-hexoses are considered rare sugars, as they rarely occur in nature and are thus very expensive. L-Hexoses are important components of biologically relevant compounds as well as being used as precursors for certain pharmaceutical drugs and thus play an important role in the pharmaceutical industry. Many general strategies have been established for the synthesis of L-hexoses; however, the only one used in the biotechnology industry is the Izumoring strategy. In hexose Izumoring, four entrances link the D- to L-enantiomers, ketose 3-epimerases catalyze the C-3 epimerization of L-ketohexoses, and aldose isomerases catalyze the specific bioconversion of L-ketohexoses and the corresponding L-aldohexoses. In this article, recent studies on the enzymatic production of various L-hexoses are reviewed based on the Izumoring strategy.

  4. Metabolic Studies on Intermediates in the myo-Inositol Oxidation Pathway in Lilium longiflorum Pollen: I. Conversion to Hexoses.

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    Rosenfield, C L; Fann, C; Loewus, F A

    1978-01-01

    The myo-inositol oxidation pathway was investigated in regard to its role as a source of carbon for products of hexose monophosphate metabolism in germinated pollen of Lilium longiflorum Thunb., cv. Ace. myo-[2-(14)]Inositol and d-[1-(14)C]glucuronate had similar distributions of radioactivity, contributing about three times more label to polysaccharide-bound glucose than myo-[2-(3)H]inositol. In the course of glucogenesis label from the latter appeared as tritiated water in the medium. This exchange could be enhanced by supplying d-[5R,5S-(3)H]xylose instead of myo-[2-(3)H]inositol. When the former was administered, [(3)H]glucose was the only labeled sugar residue found in polysaccharide products. The soluble constituents of d-[5R,5S-(3)H]xylose-labeled pollen contained no traces of labeled xylose despite massive uptake and utilization.l-[1-(14)C]- and l-[5-(14)C]Arabinose produced similar labeling patterns in germinated pollen including incorporation of arabinosyl units into pollen tube polysaccharides and substantial glucogenesis which led to utilization of arabinose for respiration and further incorporation of labeled glucosyl units into pollen tube polysaccharides.d-[5-(3)H]Galacturonate was rapidly taken up by germinated pollen but slowly utilized, without conversion to other sugars, for incorporation into pollen tube polysaccharides. l-[6-(14)C]Gulonate was not taken up by pollen.Results strongly support a scheme of conversion from myo-inositol to hexose monophosphate and subsequent products of glucose metabolism that involves the myo-inositol oxidation pathway.

  5. Fermentation of hexoses to ethanol

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    Gustafsson, Lena [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology]|[Chalmers Univ. of Technology, Goeteborg (Sweden). Dept of Chemical Reaction Engineering

    2000-06-01

    The Goals of the project has been: to increase the ethanol yield by reducing the by-product formation, primarily biomass and glycerol, and to prevent stuck fermentations, i.e. to maintain a high ethanol production rate simultaneously with a high ethanol yield. The studies have been performed both in defined laboratory media and in a mixture of wood- and wheat hydrolysates. The yeast strains used have been both industrial strains of bakers yeast, Saccharomyces cerevisiae, and haploid laboratory strains. The Relevance of these studies with respect to production of ethanol to be used as fuel is explained by: With the traditional process design used today, it is very difficult to reach a yield of more than 90 % of the theoretical maximal value of ethanol based on fermented hexose. During 'normal' growth and fermentation conditions in either anaerobic batch or chemostat cultures, substrate is lost as biomass and glycerol in the range of 8 to 11 % and 6 to 11 % of the substrate consumed (kg/kg). It is essential to reduce these by-products. Traditional processes are mostly batch processes, in which there is a risk that the biocatalyst, i.e. the yeast, may become inactivated. If for example yeast biomass production is avoided by use of non-growing systems, the ethanol production rate is instantaneously reduced by at least 50%. Unfortunately, even if yeast biomass production is not avoided on purpose, it is well known that stuck fermentations caused by cell death is a problem in large scale yeast processes. The main reason for stuck fermentations is nutrient imbalances. For a good process economy, it is necessary to ensure process accessibility, i.e. to maintain a high and reproducible production rate. This will both considerably reduce the necessary total volume of the fermentors (and thereby the investment costs), and moreover minimize undesirable product fall-out.

  6. A comparative glycoproteome study of developing endosperm in the hexose-deficient miniature1 (mn1 seed mutant and its wild type Mn1 in maize

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    Cecilia eSilva-Sanchez

    2014-02-01

    Full Text Available In maize developing seeds, transfer cells are prominently located at the basal endosperm transfer layer (BETL. As the first filial cell layer, BETL is a gateway to sugars, nutrients and water from mother plant; and anchor of numerous functions such as sucrose turnover, auxin and cytokinin biosynthesis/accumulation, energy metabolism, defense response, and signaling between maternal and filial generations. Previous studies showed that basal developing endosperms of miniature1 (mn1 mutant seeds lacking the Mn1-encoded cell wall invertase II, are also deficient for hexose. Given the role of glucose as one of the key sugars in protein glycosylation and proper protein folding; we performed a comparative large scale glycoproteome profiling of total proteins of these two genotypes (mn1 mutant vs Mn1 wild type using 2D gel electrophoresis and glycosylation/total protein staining, followed by image analysis. Protein identification was done by LC-MS/MS. A total of 413 spots were detected; from which, 113 spots matched between the two genotypes. Of these, 45 showed > 20% decrease/increase in glycosylation level and were selected for protein identification. A large number of identified proteins showed decreased glycosylation levels in mn1 developing endosperms as compared to the Mn1. Functional classification of proteins, showed mainly of post-translational modification, protein turnover, chaperone activities, carbohydrate and amino acid biosynthesis / transport, and cell wall biosynthesis. These proteins and activities were related to endoplasmic reticulum (ER stress and unfolded protein response (UPR as a result of the low glycolsylation levels of the mutant proteins. Overall, these results provide for the first time a global glycoproteome profile of maize BETL-enriched basal endosperm to better understand their role in seed development in maize.

  7. Serum protein-bound hexose in diabetes: the effect of glycemic control.

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    Kennedy, A L; Kandell, T W; Merimee, T J

    1979-11-01

    To determine whether the carbohydrate content of serum proteins is related to overall glycemic control, we studied serum protein-bound hexose and glycosylated hemoglobin [HbA1(a+b+c)] in 37 ambulant diabetic patients and 32 nondiabetic controls. Protein-bound hexose was correlated with HbA1(a+b+c) in the diabetic patients (r = 0.36, P less than 0.025). The mean protein-bound hexose level of the diabetic patients was greater than that of the controls (190.8 versus 174.7 mg/dl, P less than 0.01), but diabetic patients with HbA1(a+b+c) less than 12% had a mean protein-bound hexose similar to the controls. In nine of the diabetic patients, mean protein-bound hexose and HbA1(a+b+c) were significantly reduced during a period of intensive outpatient care, while two major serum glycoproteins, haptoglobins and alpha-1-antitrypsin, were unchanged. Our findings support the hypothesis that increased glycosylation of serum proteins may occur in diabetes mellitus; this abnormality in serum protein-bound hexose may be corrected by close attention to overall glycemic control.

  8. Biological Sampling Variability Study

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    Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-11-08

    There are many sources of variability that exist in the sample collection and analysis process. This paper addresses many, but not all, sources of variability. The main focus of this paper was to better understand and estimate variability due to differences between samplers. Variability between days was also studied, as well as random variability within each sampler. Experiments were performed using multiple surface materials (ceramic and stainless steel), multiple contaminant concentrations (10 spores and 100 spores), and with and without the presence of interfering material. All testing was done with sponge sticks using 10-inch by 10-inch coupons. Bacillus atrophaeus was used as the BA surrogate. Spores were deposited using wet deposition. Grime was coated on the coupons which were planned to include the interfering material (Section 3.3). Samples were prepared and analyzed at PNNL using CDC protocol (Section 3.4) and then cultured and counted. Five samplers were trained so that samples were taken using the same protocol. Each sampler randomly sampled eight coupons each day, four coupons with 10 spores deposited and four coupons with 100 spores deposited. Each day consisted of one material being tested. The clean samples (no interfering materials) were run first, followed by the dirty samples (coated with interfering material). There was a significant difference in recovery efficiency between the coupons with 10 spores deposited (mean of 48.9%) and those with 100 spores deposited (mean of 59.8%). There was no general significant difference between the clean and dirty (containing interfering material) coupons or between the two surface materials; however, there was a significant interaction between concentration amount and presence of interfering material. The recovery efficiency was close to the same for coupons with 10 spores deposited, but for the coupons with 100 spores deposited, the recovery efficiency for the dirty samples was significantly larger (65

  9. Individual and combined usefulness of lipid associated sialic acid, mucoid proteins and hexoses as tumor markers in breast carcinoma.

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    Patel, P S; Baxi, B R; Adhvaryu, S G; Balar, D B

    1990-06-15

    Serum levels of lipid associated sialic acid (LASA), mucoid proteins (MP) and hexoses (galactose + mannose) were measured in 41 breast cancer patients, 14 patients with benign breast diseases and 36 healthy age matched female individuals. In breast carcinoma patients, we have observed significant increase in the levels of the three markers compared with the controls (P less than 0.001) and in MP and hexoses compared to the patients with benign breast diseases (P less than 0.001). LASA and hexoses levels were significantly higher in benign breast diseases with respect to controls (P less than 0.001 and P less than 0.01, respectively). We evaluated the sensitivity and specificity of the markers individually and in combination. MP were most sensitive (71.8%) and specific (71.4%). Both sensitivity and specificity were increased when combinations of the markers were studied. Combination of MP with LASA was most sensitive (97.4%) while the combination of MP and hexoses was most specific (92.9%). LASA was significantly elevated in infiltrating duct carcinoma compared to lobular carcinoma (P less than 0.001). MP and hexoses also showed higher mean value in infiltrating duct carcinoma than lobular carcinoma. The present study suggests that the combination of the markers investigated might be useful for diagnosis and classification of breast carcinoma.

  10. [Glycoprotein hexoses in feces of infants with lactose intolerance].

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    Filippvskiĭ, G K; Klimov, L Ia

    1995-01-01

    A modified method for estimation of total glycoprotein hexoses in feces, based on their measurements in the blood serum, is presented. Sixty-six nursing children with lactose intolerance, breastfed or formula fed, were examined; formula fed babies were kept on mixtures with high and low lactose content. Glycoprotein hexose parameters were as follows (X +/- m): 13.51 +/- 1.93, 12.05 +/- 2.20, and 3.69 +/- 0.47 g/l feces. In control children without lactose intolerance (n = 33) this value was 3.6 +/- 0.79 g/l. Increased glycoprotein excretion is connected with glycocalix and small intestinal enterocyte alteration.

  11. The Thermoanaerobacter glycobiome reveals mechanisms of pentose and hexose co-utilization in bacteria.

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    Lu Lin

    2011-10-01

    Full Text Available Thermoanaerobic bacteria are of interest in cellulosic-biofuel production, due to their simultaneous pentose and hexose utilization (co-utilization and thermophilic nature. In this study, we experimentally reconstructed the structure and dynamics of the first genome-wide carbon utilization network of thermoanaerobes. The network uncovers numerous novel pathways and identifies previously unrecognized but crucial pathway interactions and the associated key junctions. First, glucose, xylose, fructose, and cellobiose catabolism are each featured in distinct functional modules; the transport systems of hexose and pentose are apparently both regulated by transcriptional antiterminators of the BglG family, which is consistent with pentose and hexose co-utilization. Second, glucose and xylose modules cooperate in that the activity of the former promotes the activity of the latter via activating xylose transport and catabolism, while xylose delays cell lysis by sustaining coenzyme and ion metabolism. Third, the vitamin B₁₂ pathway appears to promote ethanologenesis through ethanolamine and 1, 2-propanediol, while the arginine deiminase pathway probably contributes to cell survival in stationary phase. Moreover, by experimentally validating the distinct yet collaborative nature of glucose and xylose catabolism, we demonstrated that these novel network-derived features can be rationally exploited for product-yield enhancement via optimized timing and balanced loading of the carbon supply in a substrate-specific manner. Thus, this thermoanaerobic glycobiome reveals novel genetic features in carbon catabolism that may have immediate industrial implications and provides novel strategies and targets for fermentation and genome engineering.

  12. Fermentation of oxidized hexose derivatives by Clostridium acetobutylicum

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    Servinsky, Matthew D; Liu, Sanchao; Gerlach, Elliot S; Germane, Katherine L; Sund, Christian J.

    2014-01-01

    Background Clostridium acetobutylicum fermentations are promising for production of commodity chemicals from heterogeneous biomass due to the wide range of substrates the organism can metabolize. Much work has been done to elucidate the pathways for utilization of aldoses, but little is known about metabolism of more oxidized substrates. Two oxidized hexose derivatives, gluconate and galacturonate, are present in low cost feedstocks, and their metabolism will contribute to overall metabolic o...

  13. Characterization of hexose transporters in Yarrowia lipolytica reveals new groups of Sugar Porters involved in yeast growth.

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    Lazar, Zbigniew; Neuvéglise, Cécile; Rossignol, Tristan; Devillers, Hugo; Morin, Nicolas; Robak, Małgorzata; Nicaud, Jean-Marc; Crutz-Le Coq, Anne-Marie

    2017-03-01

    Sugar assimilation has been intensively studied in the model yeast S. cerevisiae, and for two decades, it has been clear that the homologous HXT genes, which encode a set of hexose transporters, play a central role in this process. However, in the yeast Yarrowia lipolytica, which is well-known for its biotechnological applications, sugar assimilation is only poorly understood, even though this yeast exhibits peculiar intra-strain differences in fructose uptake: some strains (e.g., W29) are known to be slow-growing in fructose while others (e.g., H222) grow rapidly under the same conditions. Here, we retrieved 24 proteins of the Sugar Porter family from these two strains, and determined that at least six of these proteins can function as hexose transporters in the heterologous host Saccharomyces cerevisiae EBY.VW4000. Transcriptional studies and deletion analysis in Y. lipolytica indicated that two genes, YHT1 and YHT4, are probably the main players in both strains, with a similar role in the uptake of glucose, fructose, and mannose at various concentrations. The other four genes appear to constitute a set of 'reservoir' hexose transporters with an as-yet unclear physiological role. Furthermore, through examining Sugar Porters of the entire Yarrowia clade, we show that they constitute a dynamic family, within which hexose transport genes have been duplicated and lost several times. Our phylogenetic analyses support the existence of at least three distinct evolutionary groups of transporters which allow yeasts to grow on hexoses. In addition to the well-known and widespread Hxt-type transporters (which are not essential in Y. lipolytica), we highlight a second group of transporters, represented by Yht1, which are phylogenetically related to sensors that play a regulatory role in S. cerevisiae, and a third group, represented by Yht4, previously thought to contain only high-affinity glucose transporters related to Hgt1of Kluyveromyces lactis.

  14. Fermentation of oxidized hexose derivatives by Clostridium acetobutylicum.

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    Servinsky, Matthew D; Liu, Sanchao; Gerlach, Elliot S; Germane, Katherine L; Sund, Christian J

    2014-09-18

    Clostridium acetobutylicum fermentations are promising for production of commodity chemicals from heterogeneous biomass due to the wide range of substrates the organism can metabolize. Much work has been done to elucidate the pathways for utilization of aldoses, but little is known about metabolism of more oxidized substrates. Two oxidized hexose derivatives, gluconate and galacturonate, are present in low cost feedstocks, and their metabolism will contribute to overall metabolic output of these substrates. A complete metabolic network for glucose, gluconate, and galacturonate utilization was generated using online databases, previous studies, genomic context, and experimental data. Gluconate appears to be metabolized via the Entner-Doudoroff pathway, and is likely dehydrated to 2-keto-3-deoxy-gluconate before phosphorylation to 2-keto-3-deoxy-6-P-gluconate. Galacturonate appears to be processed via the Ashwell pathway, converging on a common metabolite for gluconate and galacturonate metabolism, 2-keto-3-deoxygluconate. As expected, increasingly oxidized substrates resulted in increasingly oxidized products with galacturonate fermentations being nearly homoacetic. Calculations of expected ATP and reducing equivalent yields and experimental data suggested galacturonate fermentations were reductant limited. Galacturonate fermentation was incomplete, which was not due solely to product inhibition or the inability to utilize low concentrations of galacturonate. Removal of H2 and CO2 by agitation resulted in faster growth, higher cell densities, formation of relatively more oxidized products, and higher product yields for cultures grown on glucose or gluconate. In contrast, cells grown on galacturonate showed reduced growth rates upon agitation, which was likely due to loss in reductant in the form of H2. The growth advantage seen on agitated glucose or gluconate cultures could not be solely attributed to improved ATP economics, thereby indicating other factors are

  15. Effects of insulin on hexose transport across blood-brain barrier in normoglycemia

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    Namba, H.; Lucignani, G.; Nehlig, A.; Patlak, C.; Pettigrew, K.; Kennedy, C.; Sokoloff, L.

    1987-03-01

    The effects of insulin on 3-O-(/sup 14/C) methylglucose transport across the blood-brain barrier (BBB) were studied in conscious rats under steady-state normoglycemic conditions. The (/sup 14/C)methylglucose was infused intravenously at a constant rate, and animals were killed at various times between 5 and 30 min after the initiation of the infusion. The time course of the arterial plasma concentration of (/sup 14/C)methylglucose was determined in timed arterial blood samples taken during the infusion. Local cerebral tissue concentrations of (/sup 14/C)methylglucose at the time of killing were determined by quantitative autoradiography of brain sections. The rate constants for inward and outward transport of (/sup 14/C)methylglucose across the BBB, K/sub 1/, and k/sub 2/, respectively, were estimated by a least-squares, best-fit of a kinetic equation to the measured time courses of plasma and tissue concentrations. The equilibrium distribution ration, K/sub 1//k/sub 2/, for (/sup 14/C)methylglucose in brain increased by approx. 10-11% in the hyperinsulinemic animals. Because 3-O-(/sup 14/C)methylglucose shares the same carrier that transports glucose and other hexoses across the BBB, these results suggest that hyperinsulinemia decreases the rate constants for transport but increases the distribution space for hexoses in brain. These effects are, however, quite small and are probably minor or negligible when compared with the major effects of insulin in other tissues.

  16. Active Hexose Correlated Compound Activates Immune Function to Decrease Chlamydia trachomatis Shedding in a Murine Stress Model

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    Belay, Tesfaye; Fu, Chih-Lung; Woart, Anthony

    2015-01-01

    A cold-induced stress mouse model for investigating chlamydia genital infection and immune response analysis was established in our laboratory. Previous results showed that cold-induced stress results in suppression of the immune response and increased intensity of chlamydia genital infection in the mouse model. The purpose of the present study was to evaluate the potential therapeutic value of active hexose correlated compound (AHCC) against chlamydia genital infection in mice. AHCC is an ex...

  17. Down-Regulating CsHT1, a Cucumber Pollen-Specific Hexose Transporter, Inhibits Pollen Germination, Tube Growth, and Seed Development.

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    Cheng, Jintao; Wang, Zhenyu; Yao, Fengzhen; Gao, Lihong; Ma, Si; Sui, Xiaolei; Zhang, Zhenxian

    2015-06-01

    Efficient sugar transport is needed to support the high metabolic activity of pollen tubes as they grow through the pistil. Failure of transport results in male sterility. Although sucrose transporters have been shown to play a role in pollen tube development, the role of hexoses and hexose transporters is not as well established. The pollen of some species can grow in vitro on hexose as well as on sucrose, but knockouts of individual hexose transporters have not been shown to impair fertilization, possibly due to transporter redundancy. Here, the functions of CsHT1, a hexose transporter from cucumber (Cucumis sativus), are studied using a combination of heterologous expression in yeast (Saccharomyces cerevisiae), histochemical and immunohistochemical localization, and reverse genetics. The results indicate that CsHT1 is a plasma membrane-localized hexose transporter with high affinity for glucose, exclusively transcribed in pollen development and expressed both at the levels of transcription and translation during pollen grain germination and pollen tube growth. Overexpression of CsHT1 in cucumber pollen results in a higher pollen germination ratio and longer pollen tube growth than wild-type pollen in glucose- or galactose-containing medium. By contrast, antisense suppression of CsHT1 leads to inhibition of pollen germination and pollen tube elongation in the same medium and results in a decrease of seed number per fruit and seed size when antisense transgenic pollen is used to fertilize wild-type or transgenic cucumber plants. The important role of CsHT1 in pollen germination, pollen tube growth, and seed development is discussed. © 2015 American Society of Plant Biologists. All Rights Reserved.

  18. Hexose transporters of a hemibiotrophic plant pathogen: functional variations and regulatory differences at different stages of infection.

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    Lingner, Ulrike; Münch, Steffen; Deising, Holger B; Sauer, Norbert

    2011-06-10

    Plant pathogenic fungi use a wide range of different strategies to gain access to the carbon sources of their host plants. The hemibiotrophic maize pathogen Colletotrichum graminicola (teleomorph Glomerella graminicola) colonizes its host plants, and, after a short biotrophic phase, switches to destructive, necrotrophic development. Here we present the identification of five hexose transporter genes from C. graminicola, CgHXT1 to CgHXT5, the functional characterization of the encoded proteins, and detailed expression studies for these genes during vegetative and pathogenic development. Whereas CgHXT4 is expressed under all conditions analyzed, transcript abundances of CgHXT1 and CgHXT3 are transiently up-regulated during the biotrophic phase, and CgHXT2 and CgHXT5 are expressed exclusively during necrotrophic development. Analyses of the encoded proteins characterized CgHXT5 as a low-affinity/high-capacity hexose transporter with a narrow substrate specificity for glucose and mannose. In contrast, CgHXT1 to CgHXT3 are high affinity/low capacity transporters that also accept other substrates, including fructose, galactose, or xylose. CgHXT4, the largest of the identified proteins, has only little transport activity and may function as a sugar sensor. Phylogenetic studies revealed hexose transporters closely related to the five CgHXT proteins also in other pathogenic fungi suggesting conserved functions of these proteins during fungal pathogenesis.

  19. Bioconversion of corn stover derived pentose and hexose to ethanol using cascade simultaneous saccharification and fermentation (CSSF).

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    Li, Xuan; Kim, Tae Hyun

    2012-01-01

    A cascade type of fermentation, designated the cascade simultaneous saccharification and fermentation (CSSF), was studied to convert corn stover derived pentose and hexose to ethanol with reduced enzyme input. In detail, each step of CSSF utilizes two sequential SSF phases operating on pentose and hexose, i.e., pentose conversion using xylanase, endo-glucanase, and recombinant Escherichia coli (KO11) with minimal glucose conversion in the first phase SSF, and hexose conversion in the second phase SSF using cellulase, β-glucosidase, and Saccharomyces cerevisiae (D(5)A). In this cascade scheme, multiple stages of 1st and 2nd phase SSF were performed in series; enzymes are recycled from the fermentation broth of the last stage for the use of the next stage. This bioconversion process yielded up to 60% of the theoretical maximum ethanol yield based on the total sugars in untreated corn stover, while enzyme loadings were reduced by 50% (v/v) and the final ethanol concentration reached 27 g/l.

  20. In situ analysis of enzymes involved in sucrose to hexose-phosphate conversion during stolon-to-tuber transition of potato

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    Appeldoorn, N.J.G.; Sergeeva, L.; Vreugdenhil, D.; Plas, van der L.H.W.; Visser, R.G.F.

    2002-01-01

    An in situ study of enzymes involved in sucrose to hexose-phosphate conversion during in vitro stolon-to-tuber transition of potato (Solanum tuberosum L. cv. Bintje) was employed to follow developmental changes in spatial patterns. In situ activity of the respective enzymes was visualized by specifi

  1. Expression of the Arabidopsis high-affinity hexose transporter STP13 correlates with programmed cell death.

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    Norholm, Morten H H; Nour-Eldin, Hussam H; Brodersen, Peter; Mundy, John; Halkier, Barbara A

    2006-04-17

    We report the biochemical characterization in Xenopus oocytes of the Arabidopsis thaliana membrane protein, STP13, as a high affinity, hexose-specific H(+)-symporter. Studies with kinase activators suggest that it is negatively regulated by phosphorylation. STP13 promoter GFP reporter lines show GFP expression only in the vascular tissue in emerging petals under non-stressed conditions. Quantitative PCR and the pSTP13-GFP plants show induction of STP13 in programmed cell death (PCD) obtained by treatments with the fungal toxin fumonisin B1 and the pathogen Pseudomonas syringae. A role for STP13 in PCD is supported by microarray data from e.g. plants undergoing senescence and a strong correlation between STP13 transcripts and the PCD phenotype in different accelerated cell death (acd11) mutants.

  2. Transcription of hexose transporters of Saccharomyces cerevisiae is affected by change in oxygen provision

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    Ruohonen Laura

    2008-03-01

    Full Text Available Abstract Background The gene family of hexose transporters in Saccharomyces cerevisiae consists of 20 members; 18 genes encoding transporters (HXT1-HXT17, GAL2 and two genes encoding sensors (SNF3, RGT2. The effect of oxygen provision on the expression of these genes was studied in glucose-limited chemostat cultivations (D = 0.10 h-1, pH 5, 30°C. Transcript levels were measured from cells grown in five steady state oxygen levels (0, 0.5, 1, 2.8 and 20.9% O2, and from cells under conditions in which oxygen was introduced to anaerobic cultures or removed from cultures receiving oxygen. Results The expression pattern of the HXT gene family was distinct in cells grown under aerobic, hypoxic and anaerobic conditions. The transcription of HXT2, HXT4 and HXT5 was low when the oxygen concentration in the cultures was low, both under steady state and non-steady state conditions, whereas the expression of HXT6, HXT13 and HXT15/16 was higher in hypoxic than in fully aerobic or anaerobic conditions. None of the HXT genes showed higher transcript levels in strictly anaerobic conditions. Expression of HXT9, HXT14 and GAL2 was not detected under the culture conditions studied. Conclusion When oxygen becomes limiting in a glucose-limited chemostat cultivation, the glucose uptake rate per cell increases. However, the expression of none of the hexose transporter encoding genes was increased in anaerobic conditions. It thus seems that the decrease in the moderately low affinity uptake and consequently the relative increase of high affinity uptake may itself allow the higher specific glucose consumption rate to occur in anaerobic compared to aerobic conditions.

  3. Hexose metabolism in pancreatic islets: the Pasteur effect.

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    Malaisse, W J; Rasschaert, J; Zähner, D; Sener, A

    1988-02-01

    In rat pancreatic islets, hypoxia severely decreased both the oxidation of D-[U-14C]glucose and the release of insulin evoked by D-glucose. The production of [14C]lactate was increased in the hypoxic islets, the relative magnitude of such an increment being greater at low (2.8 mM) than high (8.3 and 16.7 mM) D-glucose concentrations. Hypoxia increased the detritiation of D-[5-3H]glucose at low glucose concentration (2.8 mM), failed to affect 3H2O production at an intermediate glucose level (8.3 mM), and inhibited the utilization of D-[5-3H]glucose at a higher hexose concentration (16.7 mM). In tumoral islet cells (RINm5F line) exposed to 16.7 mM D-glucose, hypoxia decreased D-[U-14C]glucose oxidation to the same extent as in normal islet cells, but increased the production of [14C]lactate and 3H2O to a greater extent than in normal islets. These findings indicate that the Pasteur effect is operative in islet cells. The experimental data also suggest that, under normal conditions of oxygenation, high concentrations of D-glucose lead to both activation of phosphofructokinase and stimulation of mitochondrial oxidative events in normal, but not tumoral, islet cells.

  4. Search for Variable Stars and Their Study

    Science.gov (United States)

    Kokumbaeva, R. I.; Zakhozhay, V. A.; Khruslov, A. V.

    We search for variable stars and study them using our CCD observations, observations available in the CSS, NSVS, ASAS-3 and Super-WASP online public archives.Our CCD observations were performed using the Zeiss- 1000 telescope of the V.G. Fesenkov Astrophysical Institute's Tien-Shan Astronomical Observatory. Earlier, as a result of our search using CCD images, we detected 27 new variable stars; using the NSVS and SuperWASP databases, we detected 12 new red semiregular and irregular variable stars.In this paper, we present our study of seven known variables based on the ASAS-3 and SuperWASP databases. All these stars remained poorly studied, their light elements were unknown, variability types were considered preliminary only. We studied two eclipsing variables (FY And and V2250 Sgr) and five Mira-stars (BZ Sco, CZ Sco, FK Sco, V880 Sco and V1818 Sgr).

  5. Hexose-6-kinases in germinating honey locust cotyledons: substrate specificity of D-fructo-6-kinase.

    Science.gov (United States)

    Myers, D; Matheson, N K

    1994-11-01

    Extracts of the cotyledons of germinated honey locust (Gleditsia triacanthos) seeds, which contain galactomannan as a reserve polysaccharide in the endosperm, were fractionated by chromatography and the fractions examined for the presence of a specific manno-6-kinase which could phosphorylate the D-mannose released by hydrolysis of galactomannan. One particulate hexokinase (the major hexose-6-kinase fraction) and two soluble hexokinase fractions (the minor portion), as well as a soluble fructo-6-kinase fraction, were initially separated. From chromatography, electrophoresis and kinetic studies, no evidence for a specific manno-kinase was obtained. This and the level and kinetic behaviour of the particulate hexokinase implicated it as the enzyme catalysing the phosphorylation of released D-mannose. The fructo-kinase activity was further separated into three fractions. Kinetic studies on one of these with native and synthetic substrates indicated that the structural requirements for the monosaccharide substrate were a beta-D-anomeric 2-OH in the furanose ring, a 4-OH trans to the D-5-CH2OH and a -CH2OH substituent on C2 (trans to the 5-CH2OH) which could be modified. The orientation of the hydroxyl on C-3 had only a limited effect.

  6. Genomes of rumen bacteria encode atypical pathways for fermenting hexoses to short-chain fatty acids

    KAUST Repository

    Hackmann, Timothy J.

    2017-09-11

    Bacteria have been thought to follow only a few well-recognized biochemical pathways when fermenting glucose or other hexoses. These pathways have been chiseled in the stone of textbooks for decades, with most sources rendering them as they appear in the classic 1986 text by Gottschalk. Still, it is unclear how broadly these pathways apply, given that they were established and delineated biochemically with only a few model organisms. Here we show that well-recognized pathways often cannot explain fermentation products formed by bacteria. In the most extensive analysis of its kind, we reconstructed pathways for glucose fermentation from genomes of 48 species and subspecies of bacteria from one environment (the rumen). In total, 44% of these bacteria had atypical pathways, including several that are completely unprecedented for bacteria or any organism. In detail, 8% of bacteria had an atypical pathway for acetate formation; 21% for propionate or succinate formation; 6% for butyrate formation; and 33% had an atypical or incomplete Embden-Meyerhof-Parnas pathway. This study shows that reconstruction of metabolic pathways-a common goal of omics studies-could be incorrect if well-recognized pathways are used for reference. Further, it calls for renewed efforts to delineate fermentation pathways biochemically. This article is protected by copyright. All rights reserved.

  7. Reduction of glucose uptake through inhibition of hexose transporters and enhancement of their endocytosis by methylglyoxal in Saccharomyces cerevisiae.

    Science.gov (United States)

    Yoshida, Aya; Wei, Dandan; Nomura, Wataru; Izawa, Shingo; Inoue, Yoshiharu

    2012-01-02

    Diabetes mellitus is characterized by an impairment of glucose uptake even though blood glucose levels are increased. Methylglyoxal is derived from glycolysis and has been implicated in the development of diabetes mellitus, because methylglyoxal levels in blood and tissues are higher in diabetic patients than in healthy individuals. However, it remains to be elucidated whether such factors are a cause, or consequence, of diabetes. Here, we show that methylglyoxal inhibits the activity of mammalian glucose transporters using recombinant Saccharomyces cerevisiae cells genetically lacking all hexose transporters but carrying cDNA for human GLUT1 or rat GLUT4. We found that methylglyoxal inhibits yeast hexose transporters also. Glucose uptake was reduced in a stepwise manner following treatment with methylglyoxal, i.e. a rapid reduction within 5 min, followed by a slow and gradual reduction. The rapid reduction was due to the inhibitory effect of methylglyoxal on hexose transporters, whereas the slow and gradual reduction seemed due to endocytosis, which leads to a decrease in the amount of hexose transporters on the plasma membrane. We found that Rsp5, a HECT-type ubiquitin ligase, is responsible for the ubiquitination of hexose transporters. Intriguingly, Plc1 (phospholipase C) negatively regulated the endocytosis of hexose transporters in an Rsp5-dependent manner, although the methylglyoxal-induced endocytosis of hexose transporters occurred irrespective of Plc1. Meanwhile, the internalization of hexose transporters following treatment with methylglyoxal was delayed in a mutant defective in protein kinase C.

  8. Robustness studies on coal gasification process variables

    Directory of Open Access Journals (Sweden)

    RLJ Coetzer

    2004-12-01

    Full Text Available Optimisation of the Sasol-Lurgi gasification process was carried out by utilising the method of Factorial Experimental Design on the process variables of interest from a specifically equipped full-scale test gasifier. The process variables that govern gasification are not always fully controllable during normal operation. This paper discusses the application of statistical robustness studies as a method for determining the most efficient combination of process variables that might be hard-to-control during normal operation. Response surface models were developed in the process variables for each of the performance variables. It will be shown how statistical robustness studies provided the optimal conditions for sustainable gasifier operability and throughput. In particular, the optimum operability region is significantly expanded towards higher oxygen loads by changing and controlling the particle size distribution of the coal.

  9. Use of a selective inhibitor to define the chemotherapeutic potential of the plasmodial hexose transporter in different stages of the parasite's life cycle.

    Science.gov (United States)

    Slavic, Ksenija; Delves, Michael J; Prudêncio, Miguel; Talman, Arthur M; Straschil, Ursula; Derbyshire, Elvira T; Xu, Zhengyao; Sinden, Robert E; Mota, Maria M; Morin, Christophe; Tewari, Rita; Krishna, Sanjeev; Staines, Henry M

    2011-06-01

    During blood infection, malarial parasites use D-glucose as their main energy source. The Plasmodium falciparum hexose transporter (PfHT), which mediates the uptake of D-glucose into parasites, is essential for survival of asexual blood-stage parasites. Recently, genetic studies in the rodent malaria model, Plasmodium berghei, found that the orthologous hexose transporter (PbHT) is expressed throughout the parasite's development within the mosquito vector, in addition to being essential during intraerythrocytic development. Here, using a D-glucose-derived specific inhibitor of plasmodial hexose transporters, compound 3361, we have investigated the importance of D-glucose uptake during liver and transmission stages of P. berghei. Initially, we confirmed the expression of PbHT during liver stage development, using a green fluorescent protein (GFP) tagging strategy. Compound 3361 inhibited liver-stage parasite development, with a 50% inhibitory concentration (IC₅₀) of 11 μM. This process was insensitive to the external D-glucose concentration. In addition, compound 3361 inhibited ookinete development and microgametogenesis, with IC₅₀s in the region of 250 μM (the latter in a D-glucose-sensitive manner). Consistent with our findings for the effect of compound 3361 on vector parasite stages, 1 mM compound 3361 demonstrated transmission blocking activity. These data indicate that novel chemotherapeutic interventions that target PfHT may be active against liver and, to a lesser extent, transmission stages, in addition to blood stages.

  10. Real Time Study and Related Variables

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-qing

    2016-01-01

    This paper first, illustrates the advantages of applying real time study to linguistic researches. Second, this paper also compares linguistic variables with linguistic variant; nasality, stronger constraint and weaker constraint have been clearly de-fined as well.

  11. [The research protocol IV: study variables].

    Science.gov (United States)

    Villasís-Keever, Miguel Ángel; Miranda-Novales, María Guadalupe

    2016-01-01

    The variables in a research study are all that is measured, the information collected, or the data that is collected in order to answer the research questions, which are specified in the objectives. Their selection is essential to the research protocol. This article aims to point out the elements to be considered in the section of the variables. To avoid ambiguity, it is necessary to select only those that will help achieve the study objectives. It should subsequently be defined how they will be measured to ensure that the findings can be replicated; it is therefore desirable to include conceptual and operational definitions. From the methodological point of view, the classification of variables helps us understand how the relationship between them is conceptualized. Depending on the study design, the independent, dependent, universal, and confounding variables should be noted. Another indispensable element for planning statistical analyses is the scale of variable measurement. Therefore, one must specify whether the variables correspond to one of the following four: qualitative nominal, qualitative ordinal, quantitative range, or quantitative ratio. Finally, we should detail the measurement units of each variable.

  12. Study of branes with variable tension

    CERN Document Server

    Aros, Rodrigo

    2016-01-01

    In this work we study a brane world model with variable tension which gives rise to four dimensional cosmologies. The brane worlds obtained correspond to E\\"{o}tv\\"{o}s branes whose (internal) geometry can be casted as either a four dimensional (A)dS$_{4}$ or a standard radiation period cosmology. The matter dominated period is discussed as well.

  13. Seed filling in domesticated maize and rice depends on SWEET-mediated hexose transport.

    Science.gov (United States)

    Sosso, Davide; Luo, Dangping; Li, Qin-Bao; Sasse, Joelle; Yang, Jinliang; Gendrot, Ghislaine; Suzuki, Masaharu; Koch, Karen E; McCarty, Donald R; Chourey, Prem S; Rogowsky, Peter M; Ross-Ibarra, Jeffrey; Yang, Bing; Frommer, Wolf B

    2015-12-01

    Carbohydrate import into seeds directly determines seed size and must have been increased through domestication. However, evidence of the domestication of sugar translocation and the identities of seed-filling transporters have been elusive. Maize ZmSWEET4c, as opposed to its sucrose-transporting homologs, mediates transepithelial hexose transport across the basal endosperm transfer layer (BETL), the entry point of nutrients into the seed, and shows signatures indicative of selection during domestication. Mutants of both maize ZmSWEET4c and its rice ortholog OsSWEET4 are defective in seed filling, indicating that a lack of hexose transport at the BETL impairs further transfer of sugars imported from the maternal phloem. In both maize and rice, SWEET4 was likely recruited during domestication to enhance sugar import into the endosperm.

  14. Transport and utilization of hexoses and pentoses in the halotolerant yeast Debaryomyces hansenii.

    Science.gov (United States)

    Nobre, A; Lucas, C; Leão, C

    1999-08-01

    Debaryomyces hansenii is a yeast species that is known for its halotolerance. This organism has seldom been mentioned as a pentose consumer. In the present work, a strain of this species was investigated with respect to the utilization of pentoses and hexoses in mixtures and as single carbon sources. Growth parameters were calculated for batch aerobic cultures containing pentoses, hexoses, and mixtures of both types of sugars. Growth on pentoses was slower than growth on hexoses, but the values obtained for biomass yields were very similar with the two types of sugars. Furthermore, when mixtures of two sugars were used, a preference for one carbon source did not inhibit consumption of the other. Glucose and xylose were transported by cells grown on glucose via a specific low-affinity facilitated diffusion system. Cells derepressed by growth on xylose had two distinct high-affinity transport systems for glucose and xylose. The sensitivity of labeled glucose and xylose transport to dissipation of the transmembrane proton gradient by the protonophore carbonyl cyanide m-chlorophenylhydrazone allowed us to consider these transport systems as proton symports, although the cells displayed sugar-associated proton uptake exclusively in the presence of NaCl or KCl. When the V(max) values of transport systems for glucose and xylose were compared with glucose- and xylose-specific consumption rates during growth on either sugar, it appeared that transport did not limit the growth rate.

  15. Mobile Variable Depth Sampling System Design Study

    Energy Technology Data Exchange (ETDEWEB)

    BOGER, R.M.

    2000-08-25

    A design study is presented for a mobile, variable depth sampling system (MVDSS) that will support the treatment and immobilization of Hanford LAW and HLW. The sampler can be deployed in a 4-inch tank riser and has a design that is based on requirements identified in the Level 2 Specification (latest revision). The waste feed sequence for the MVDSS is based on Phase 1, Case 3S6 waste feed sequence. Technical information is also presented that supports the design study.

  16. MEASURING VARIABILITY SOURCES IN NMR METABOLOMIC STUDIES

    OpenAIRE

    Rozet, Eric; de Tullio, Pascal; Hubert, Philippe; Govaerts., B.

    2013-01-01

    Due to the huge amount of information available in NMR spectra obtained from the analysis of metabolomic experiments, multivariate analysis such as Principal Component Analysis (PCA) are required to understand the influence of treatments over the metabolites [1]. However, many experiments in metabolomics studies have more complexes variability structures than simply comparing several treatments: they may include time effects, biological effects such as diet or hormonal status, and other bloc...

  17. Variability Study of the S5 Sample

    Indian Academy of Sciences (India)

    Jun Liu; Lang Cui; Xiang Liu; Zhen Ding; Hua-Gang Song

    2014-09-01

    We present the results of flux density monitoring of the S5 sample at 5GHz with the Urumqi 25-m radio telescope during Dec. 2008 and Nov. 2009. Most sources exhibited > 2% rms variation in our one-year monitoring. Twenty-five highly variable sources were detected at a confidence level of 99%. Weaker sources show larger amplitude of variability. Sources that have a steep spectral index are not as variable in flux density as the flat spectrum objects. No galactic dependent variability was found. Supplemental IDV observations for several strong variables were performed in order to search for possible rapid variability, and to compare variability on different time-scales. The absence of short time-scale variability in S5 0633+73 indicates that mid time-scale variability is a main source of intrinsic origin.

  18. SLUDGE BATCH VARIABILITY STUDY WITH FRIT 418

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, F.; Edwards, T.

    2010-11-29

    The Defense Waste Processing Facility (DWPF) initiated processing Sludge Batch 6 (SB6) in the summer of 2010. In support of processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frit 418 to process SB6. This recommendation was based on assessments of the compositional projections for SB6 available at the time from the Liquid Waste Organization (LWO) and SRNL (using a model-based approach). To support qualification of SB6, SRNL executed a variability study to assess the applicability of the current durability models for SB6. The durability models were assessed over the expected Frit 418-SB6 composition range. Seventeen glasses were selected for the variability study based on the sludge projections used in the frit recommendation. Five of the glasses are based on the centroid of the compositional region, spanning a waste loading (WL) range of 32 to 40%. The remaining twelve glasses are extreme vertices (EVs) of the sludge region of interest for SB6 combined with Frit 418 and are all at 36% WL. These glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). After initiating the SB6 variability study, the measured composition of the SB6 Tank 51 qualification glass produced at the SRNL Shielded Cells Facility indicated that thorium was present in the glass at an appreciable concentration (1.03 wt%), which made it a reportable element for SB6. This concentration of ThO{sub 2} resulted in a second phase of experimental studies. Five glasses were formulated that were based on the centroid of the new sludge compositional region combined with Frit 418, spanning a WL range of 32 to 40%. These glasses were fabricated and characterized using chemical composition analysis and the PCT. Based on the measured PCT response, all of the glasses (with and without thorium) were acceptable with respect to the Environmental Assessment (EA) reference glass

  19. Optimization of supercritical phase and combined supercritical/subcritical conversion of lignocellulose for hexose production by using a flow reaction system.

    Science.gov (United States)

    Zhao, Yan; Lu, Wen-Jing; Wu, Hua-Yong; Liu, Jin-Wen; Wang, Hong-Tao

    2012-12-01

    A flow reaction system was utilized to investigate lignocellulose conversion using combined supercritical/subcritical conditions for hexose production. Initially, investigation of cellulose hydrolysis in supercritical water and optimization of reaction parameters were done. Oligosaccharide yields reached over 30% at cellulose concentrations of 3-5 gL(-1) and reaction times of 6-10s at 375 °C, and 2.5-4 gL(-1) and 8-10s at 380 °C. Temperatures above 380 °C were not appropriate for the supercritical phase in the combined process. Subsequently, conversion of lignocellulosic materials under combined supercritical/subcritical conditions was studied. Around 30% hexose was produced from corn stalks under the optimal parameters for supercritical (380 °C, 23-24 MPa, 9-10s) and subcritical (240 °C, 8-9 MPa, 45-50s) phases. Flow systems utilizing the combined supercritical/subcritical technology present a promising method for lignocellulosic conversion. The results of this study provide an important guide for the operational optimization and practical application of the proposed system.

  20. SALTSTONE VARIABILITY STUDY - MEASUREMENT OF POROSITY

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J; Vickie Williams, V; Tommy Edwards, T; Russell Eibling, R; Ray Schumacher, R

    2007-08-23

    One of the goals of the Saltstone Variability Study is to identify the operational and compositional variables that control or influence the important processing and performance properties of Saltstone mixes. One of the key performance properties is porosity which is a measure of the volume percent of a cured grout that is occupied by salt solution (for the saturated case). This report presents (1) the results of efforts to develop a method for the measurement of porosity of grout samples and (2) initial results of porosity values for samples that have been previously produced as part of the Saltstone Variability Study. A cost effective measurement method for porosity was developed that provides reproducible results, is relatively fast (30 to 60 minutes per sample) and uses a Mettler Toledo HR83 Moisture Analyzer that is already operational and routinely calibrated at Aiken County Technology Laboratory. The method involves the heating of the sample at 105 C until no further mass loss is observed. This mass loss value, which is due to water evaporation, is then used to calculate the volume percent porosity of the mix. The results of mass loss for mixes at 105 C were equivalent to the results obtained using thermal gravimetric analysis. The method was validated by comparing measurements of mass loss at 105 C for cured portland cement in water mixes to values presented in the literature for this system. A stereopycnometer from Quantachrome Instruments was selected to measure the cured grout bulk densities. Density is a property that is required to calculate the porosities. A stereopycnometer was already operational at Aiken County Technology Laboratory, has been calibrated using a solid stainless steel sphere of known volume, is cost effective and fast ({approx}15 minutes per sample). Cured grout densities are important in their own right because they can be used to project the volume of waste form produced from a given amount of salt feed of known composition. For

  1. SLUDGE BATCH 7B GLASS VARIABILITY STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, F.; Edwards, T.

    2011-10-25

    The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 7b (SB7b). In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frits 418 with a 6% Na{sub 2}O addition (26 wt% Na{sub 2}O in sludge) and 702 with a 4% Na{sub 2}O addition (24 wt% Na{sub 2}O in sludge) to process SB7b. This recommendation was based on assessments of the compositional projections for SB7b available at the time from the Savannah River Remediation (SRR). To support qualification of SB7b, SRNL executed a variability study to assess the applicability of the current durability models for SB7b. The durability models were assessed over the expected composition range of SB7b, including potential caustic additions, combined with Frits 702 and 418 over a 32-40% waste loading (WL) range. Thirty four glasses were selected based on Frits 418 and 702 coupled with the sludge projections with an additional 4-6% Na{sub 2}O to reflect the potential caustic addition. Six of these glasses, based on average nominal sludge compositions including the appropriate caustic addition, were developed for both Frit 418 and Frit 702 at 32, 36 and 40% WL to provide coverage in the center of the anticipated SB7b glass region. All glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). To comply with the DWPF Glass Product Control Program, a total of thirty four glasses were fabricated to assess the applicability of the current DWPF PCCS durability models. Based on the measured PCT response, all of the glasses were acceptable with respect to the Environmental Assessment (EA) benchmark glass regardless of thermal history. The NL[B] values of the SB7b variability study glasses were less than 1.99 g/L as compared to 16.695 g/L for EA. A small number of the D-optimally selected 'outer layer' extreme vertices (EV) glasses were not

  2. Developmental changes in enzymes involved in the conversion of hexose phosphate and its subsequent metabolites during early tuberization of potato

    NARCIS (Netherlands)

    Appeldoorn, N.J.G.; Bruijn, de S.M.; Koot-Gronsveld, E.A.M.; Visser, R.G.F.; Vreugdenhil, D.; Plas, van der L.H.W.

    1999-01-01

    A highly synchronized in vitro tuberization system, based on single-node cuttings containing an axillary bud, was used to investigate the activity patterns of enzymes involved in the conversion of hexose phosphates and related products during stolon-to-tuber transition of potato (Solanum tuberosum L

  3. POMETIA (SAPINDACEAE, A STUDY IN VARIABILITY

    Directory of Open Access Journals (Sweden)

    M Jacobs

    2014-01-01

    Full Text Available A monograph   of   Pometia,   which   extends   from   Ceylon   throughout Malaysia to Samoa, with a few stations in SE. Asia and Formosa. Two species are recognized:   P. ridleyi   and   P. pinnata,   the   latter   having a particular pattern of  alternating- nerves.  Pometia pinnata is  extremely variable and clearly still in process of differentiation. From the wealth of forms,  8 formae  have  been  selected  for taxonomic  recognition,  1  of them is newly described, 7 are new combinations;  characters are found in the leaves and the inflorescence. Besides, a number of unnamed paramorphs have been described. The distribution of the variability has been sketched for each region. Details about ecology etc. are given. Specimens are cited where  appropriate  and  a general  Identification  List  is  given at the end.

  4. The effect of hexose ratios on metabolite production in Saccharomyces cerevisiae strains obtained from the spontaneous fermentation of mezcal.

    Science.gov (United States)

    Oliva Hernández, Amanda A; Taillandier, Patricia; Reséndez Pérez, Diana; Narváez Zapata, José A; Larralde Corona, Claudia Patricia

    2013-04-01

    Mezcal from Tamaulipas (México) is produced by spontaneous alcoholic fermentation using Agave spp. musts, which are rich in fructose. In this study eight Saccharomyces cerevisiae isolates obtained at the final stage of fermentation from a traditional mezcal winery were analysed in three semi-synthetic media. Medium M1 had a sugar content of 100 g l(-1) and a glucose/fructose (G/F) of 9:1. Medium M2 had a sugar content of 100 g l(-1) and a G/F of 1:9. Medium M3 had a sugar content of 200 g l(-1) and a G/F of 1:1. In the three types of media tested, the highest ethanol yield was obtained from the glucophilic strain LCBG-3Y5, while strain LCBG-3Y8 was highly resistant to ethanol and the most fructophilic of the mezcal strains. Strain LCBG-3Y5 produced more glycerol (4.4 g l(-1)) and acetic acid (1 g l(-1)) in M2 than in M1 (1.7 and 0.5 g l(-1), respectively), and the ethanol yields were higher for all strains in M1 except for LCBG-3Y5, -3Y8 and the Fermichamp strain. In medium M3, only the Fermichamp strain was able to fully consume the 100 g of fructose l(-1) but left a residual 32 g of glucose l(-1). Regarding the hexose transporters, a high number of amino acid polymorphisms were found in the Hxt1p sequences. Strain LCBG-3Y8 exhibited eight unique amino acid changes, followed by the Fermichamp strain with three changes. In Hxt3p, we observed nine amino acid polymorphisms unique for the Fermichamp strain and five unique changes for the mezcal strains.

  5. Two methods for studying the X-ray variability

    NARCIS (Netherlands)

    Yan, Shu-Ping; Ji, Li; Méndez, Mariano; Wang, Na; Liu, Siming; Li, Xiang-Dong

    2016-01-01

    The X-ray aperiodic variability and quasi-periodic oscillation (QPO) are the important tools to study the structure of the accretion flow of X-ray binaries. However, the origin of the complex X-ray variability from X-ray binaries remains yet unsolved. We proposed two methods for studying the X-ray

  6. Instrumental variables in influenza vaccination studies : mission impossible?!

    NARCIS (Netherlands)

    Groenwold, Rolf H H; Hak, Eelko; Klungel, Olaf H; Hoes, Arno W

    2009-01-01

    OBJECTIVES: Unobserved confounding has been suggested to explain the effect of influenza vaccination on mortality reported in several observational studies. An instrumental variable (IV) is strongly related to the exposure under study, but not directly or indirectly (through other variables) with th

  7. A holistic approach to study the temporal variability in gait

    OpenAIRE

    Federolf, Peter; Tecante, Karelia; Nigg, Benno

    2012-01-01

    Movement variability has become an important field of research and has been studied to gain a better understanding of the neuro-muscular control of human movements. In addition to studies investigating “amplitude variability” there are a growing number of studies assessing the “temporal variability” in movements by applying non-linear analysis techniques. One limitation of the studies available to date is that they quantify variability features in specific, pre-selected biomechanical or physi...

  8. Two methods for studying the X-ray variability

    Science.gov (United States)

    Yan, Shu-Ping; Ji, Li; Méndez, Mariano; Wang, Na; Liu, Siming; Li, Xiang-Dong

    2016-04-01

    The X-ray aperiodic variability and quasi-periodic oscillation (QPO) are the important tools to study the structure of the accretion flow of X-ray binaries. However, the origin of the complex X-ray variability from X-ray binaries remains yet unsolved. We proposed two methods for studying the X-ray variability. One is amplitude-ratio spectrum analysis method. The other is mapping analysis method. Based on the consideration that the aperiodic variability originates from all spectral components whereas the QPO originates from one spectral component, we divided the root-mean-square (rms) amplitude spectrum of the power density spectrum (PDS) broadband noise component by the amplitude spectrum of an accompanying QPO, and first identified a high-frequency (> 10 Hz) aperiodic variability from the accretion disk (Yan et al. 2013). We now present the evolution of the amplitude-ratio spectrum with the cycle phase of the heartbeat state of the microquasar GRS 1915+105. We produced the energy-frequency-power map to investigate the origin of the X-ray variability, and show that most aperiodic X-ray variability is produced in the corona, and the low-frequency aperiodic variability from the corona is significant in the hard phase of the cycle phase of the heartbeat state of GRS 1915+105 while the low-frequency aperiodic variability from the disk and the corona are both significant in the soft phase.

  9. Correlational study of psychological variables self-confidence and anxiety

    Directory of Open Access Journals (Sweden)

    Gloria González Campos

    2015-12-01

    Full Text Available Abstract The purpose of this study is to analyze the concurrent validity of the psychological variables self-confidence and anxiety among the psychological measurement instruments: Psychological Characteristics Questionnaire related to Sports Performance (CPRD; Competitive State Anxiety Inventory-2 (CSAI-2; and Sports Psychological Inventory LOEHR. For this purpose, a correlational study was conducted between the selected variables and pertinent aspects of the measurement instruments. The study has revealed that the psychological variables self-confidence and anxiety are relevant in all three instruments, although not in all of the selected items.

  10. Evaluation of active hexose correlated compound (AHCC in combination with pegylated liposomal doxorubicin for treatment of ovarian cancer

    Directory of Open Access Journals (Sweden)

    R J Hunter

    2011-09-01

    Full Text Available Summary: The objective was to define the mechanism of the growth inhibition of active hexose correlated compound (AHCC alone and evaluate its activity in combination with pegylated liposomal doxorubicin (PLD. Scientific Methods: In vitro growth inhibition assays were completed with AHCC alone and in combination with PLD in panel of human cancer cell lines  and findings confirmed in vivo in an ovarian cancer xenograft mouse model.  AHCC mechanism of action was evaluated with immunoblotting and flow cytometry studies. Major Findings: The in vitro growth inhibition assays demonstrated additive activity when AHCC is co-administered with PLD.  The combination of AHCC with PLD demonstrated a 64.1% reduction in tumor growth compared to the untreated group (p value = 0.03 and a 31.2% improvement in tumor response with combination regimen compared to PLD alone. No difference in toxicity was observed in the control or treatment groups.  An increased expression of Bcl-2 was observed and induction of apoptosis confirmed in presence of AHCC. Conclusions: There is potential improvement in PLD activity when co-administered with AHCC and decrease side effects of PLD.  A clinical study to evaluate of the combination of AHCC plus PLD in the treatment of ovarian cancer is being pursued. Industrial Relevance: This study presents an example of the successful integration of a well- known herbal supplement, AHCC, with traditional western medicine cytotoxic agent, pegylated liposomal doxorubicin, for the treatment of recurrent ovarian cancer.    In addition to providing evidence of the efficacy of AHCC, the mechanism of improved activity was also investigated.   Using a traditional approach this study provides pre-clinical data to support the benefits previously observed and reported in the clinical setting and supports future endeavors to integrate AHCC into standard of care to be given with chemotherapy. .  These finding are particularly beneficial in the

  11. Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables

    Directory of Open Access Journals (Sweden)

    JULIANA WOJCIECHOWSKI

    2015-09-01

    Full Text Available One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

  12. Active Hexose Correlated Compound Activates Immune Function to Decrease Chlamydia trachomatis Shedding in a Murine Stress Model.

    Science.gov (United States)

    Belay, Tesfaye; Fu, Chih-Lung; Woart, Anthony

    2015-01-01

    A cold-induced stress mouse model for investigating chlamydia genital infection and immune response analysis was established in our laboratory. Previous results showed that cold-induced stress results in suppression of the immune response and increased intensity of chlamydia genital infection in the mouse model. The purpose of the present study was to evaluate the potential therapeutic value of active hexose correlated compound (AHCC) against chlamydia genital infection in mice. AHCC is an extract of mushroom commonly used as a dietary supplement is known to boost the immune system. Mice were infected intravaginally with Chlamydia trachomatis after a 24-day cold-stress application. Oral administration of AHCC to stressed or non-stressed mice was carried out seven days before infection and during the course of infection along with cervicovaginal swabbing. Cytokine production by peritoneal and splenic T cells isolated from AHCC-fed stressed mice and non-stressed mice was measured ELISA. Splenic T cells from both animal groups were co-cultured with mouse monocyte J774.2 cell line or cultured by addition of supernatants of AHCC-treated J774.2 cell line for 24 hours. Infection studies showed that AHCC-feeding compared to phosphate buffered saline (PBS)-feeding to stressed mice resulted in reduced Chlamydia trachomatis shedding from the genital tract. Levels of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) were significantly increased in stressed mice receiving AHCC compared to stressed mice receiving PBS. Production of interferon gamma (IFN-γ) and interleukin 2 (IL-2) in the AHCC group was significantly high compared to production in PBS-fed group. Splenic T cells from stressed and non-stressed cultured with supernatants of AHCC-treated J774.2 cell line resulted in significantly increased TNF-α or IFN-γ production. Results obtained in this study show that AHCC improves the function of immune cells as indicated by the restoration of levels of cytokines

  13. A Study of I-Function of Several Complex Variables

    OpenAIRE

    Prathima Jayarama; Vasudevan Nambisan Theke Madam; Shantha Kumari Kurumujji

    2014-01-01

    The aim of this paper is to introduce a natural generalization of the well-known, interesting, and useful Fox H-function into generalized function of several variables, namely, the I-function of ‘‘r’’ variables. For r=1, we get the I-function introduced and studied by Arjun Rathie (1997) and, for r=2, we get I-function of two variables introduced very recently by ShanthaKumari et al. (2012). Convergent conditions, elementary properties, and special cases have also been given. T...

  14. An AO-assisted variability study of four globular clusters

    CERN Document Server

    Salinas, R; Strader, J; Hakala, P; Catelan, M; Peacock, M; Simunovic, M

    2016-01-01

    The image subtraction technique applied to study variable stars in globular clusters represented a leap in the number of new detections, with the drawback that many of these new light curves could not be transformed to magnitudes due to the severe crowding. In this paper we present observations of four Galactic globular clusters, M 2 (NGC 7089), M 10 (NGC 6254), M 80 (NGC 6093) and NGC 1261, taken with the ground-layer adaptive optics module at the SOAR Telescope, SAM. We show that the higher image quality provided by SAM allows the calibration of the light curves of the great majority of the variables near the cores of these clusters as well as the detection of new variables even in clusters where image-subtraction searches were already conducted. We report the discovery of 15 new variables in M 2 (12 RR Lyrae stars and 3 SX Phe stars), 12 new variables in M 10 (11 SX Phe and one long-period variable) and one new W UMa-type variable in NGC 1261. No new detections are found in M 80, but previous uncertain det...

  15. Identification of homogeneous and heterogeneous variables in pooled cohort studies.

    Science.gov (United States)

    Cheng, Xin; Lu, Wenbin; Liu, Mengling

    2015-06-01

    Pooled analyses integrate data from multiple studies and achieve a larger sample size for enhanced statistical power. When heterogeneity exists in variables' effects on the outcome across studies, the simple pooling strategy fails to present a fair and complete picture of the effects of heterogeneous variables. Thus, it is important to investigate the homogeneous and heterogeneous structure of variables in pooled studies. In this article, we consider the pooled cohort studies with time-to-event outcomes and propose a penalized Cox partial likelihood approach with adaptively weighted composite penalties on variables' homogeneous and heterogeneous effects. We show that our method can characterize the variables as having heterogeneous, homogeneous, or null effects, and estimate non-zero effects. The results are readily extended to high-dimensional applications where the number of parameters is larger than the sample size. The proposed selection and estimation procedure can be implemented using the iterative shooting algorithm. We conduct extensive numerical studies to evaluate the performance of our proposed method and demonstrate it using a pooled analysis of gene expression in patients with ovarian cancer. © 2015, The International Biometric Society.

  16. Peak HIV prevalence : a useful outcome variable for ecological studies

    NARCIS (Netherlands)

    Kenyon, Chris; Colebunders, Robert; Voeten, Helene; Lurie, Mark

    2013-01-01

    A key question for ecological studies with HIV as the outcome variable is what measure of HIV prevalence to use. In this study we compared the strengths and weaknesses of a variety of measures of HIV prevalence, focusing on peak HIV prevalence and HIV prevalence measured at the same time as the expo

  17. An AO-assisted Variability Study of Four Globular Clusters

    Science.gov (United States)

    Salinas, R.; Contreras Ramos, R.; Strader, J.; Hakala, P.; Catelan, M.; Peacock, M. B.; Simunovic, M.

    2016-09-01

    The image-subtraction technique applied to study variable stars in globular clusters represented a leap in the number of new detections, with the drawback that many of these new light curves could not be transformed to magnitudes due to severe crowding. In this paper, we present observations of four Galactic globular clusters, M 2 (NGC 7089), M 10 (NGC 6254), M 80 (NGC 6093), and NGC 1261, taken with the ground-layer adaptive optics module at the SOAR Telescope, SAM. We show that the higher image quality provided by SAM allows for the calibration of the light curves of the great majority of the variables near the cores of these clusters as well as the detection of new variables, even in clusters where image-subtraction searches were already conducted. We report the discovery of 15 new variables in M 2 (12 RR Lyrae stars and 3 SX Phe stars), 12 new variables in M 10 (11 SX Phe and 1 long-period variable), and 1 new W UMa-type variable in NGC 1261. No new detections are found in M 80, but previous uncertain detections are confirmed and the corresponding light curves are calibrated into magnitudes. Additionally, based on the number of detected variables and new Hubble Space Telescope/UVIS photometry, we revisit a previous suggestion that M 80 may be the globular cluster with the richest population of blue stragglers in our Galaxy. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

  18. Variability and impact on design of bioequivalence studies.

    Science.gov (United States)

    Van Peer, Achiel

    2010-03-01

    In 2008, the European Agency for the Evaluation of Medicinal Products released a draft guidance on the investigation of bioequivalence for immediate release dosage forms with systemic action to replace the former guidance of a decade ago. Revisions of the regulatory guidance are based upon many questions over the past years and sometimes continuing scientific discussions on the use of the most suitable statistical analysis methods and study designs, particularly for drugs and drug products with high within-subject variability. Although high within-subject variability is usually associated with a coefficient of variation of 30% or more, new approaches are available in the literature to allow a gradual increase and a levelling off of the bioequivalence limits to some maximum wider values (e.g. 75-133%), dependent on the increase in the within-subject variability. The two-way, cross-over single dose study measuring parent drug is still the design of first choice. A partial replicate design with repeating the reference product and scaling the bioequivalence for the reference variability are proposed for drugs with high within-subject variability. In case of high variability, more regulatory authorities may accept a two-stage or group-sequential bioequivalence design using appropriately adjusted statistical analysis. This review also considers the mechanisms why drugs and drug products may exhibit large variability. The physiological complexity of the gastrointestinal tract and the interaction with the physicochemical properties of drug substances may contribute to the variation in plasma drug concentration-time profiles of drugs and drug products and to variability between and within subjects. A review of submitted bioequivalence studies at the Food and Drug Administration's Office of Generic Drugs over the period 2003-2005 indicated that extensive pre-systemic metabolism of the drug substance was the most important explanation for consistently high variability drugs

  19. (13)C metabolic flux analysis in neurons utilizing a model that accounts for hexose phosphate recycling within the pentose phosphate pathway.

    Science.gov (United States)

    Gebril, Hoda M; Avula, Bharathi; Wang, Yan-Hong; Khan, Ikhlas A; Jekabsons, Mika B

    2016-02-01

    Glycolysis, mitochondrial substrate oxidation, and the pentose phosphate pathway (PPP) are critical for neuronal bioenergetics and oxidation-reduction homeostasis, but quantitating their fluxes remains challenging, especially when processes such as hexose phosphate (i.e., glucose/fructose-6-phosphate) recycling in the PPP are considered. A hexose phosphate recycling model was developed which exploited the rates of glucose consumption, lactate production, and mitochondrial respiration to infer fluxes through the major glucose consuming pathways of adherent cerebellar granule neurons by replicating [(13)C]lactate labeling from metabolism of [1,2-(13)C2]glucose. Flux calculations were predicated on a steady-state system with reactions having known stoichiometries and carbon atom transitions. Non-oxidative PPP activity and consequent hexose phosphate recycling, as well as pyruvate production by cytoplasmic malic enzyme, were optimized by the model and found to account for 28 ± 2% and 7.7 ± 0.2% of hexose phosphate and pyruvate labeling, respectively. From the resulting fluxes, 52 ± 6% of glucose was metabolized by glycolysis, compared to 19 ± 2% by the combined oxidative/non-oxidative pentose cycle that allows for hexose phosphate recycling, and 29 ± 8% by the combined oxidative PPP/de novo nucleotide synthesis reactions. By extension, 62 ± 6% of glucose was converted to pyruvate, the metabolism of which resulted in 16 ± 1% of glucose oxidized by mitochondria and 46 ± 6% exported as lactate. The results indicate a surprisingly high proportion of glucose utilized by the pentose cycle and the reactions synthesizing nucleotides, and exported as lactate. While the in vitro conditions to which the neurons were exposed (high glucose, no lactate or other exogenous substrates) limit extrapolating these results to the in vivo state, the approach provides a means of assessing a number of metabolic fluxes within the context of hexose phosphate recycling in the PPP from a

  20. Environmental Concern and Sociodemographic Variables: A Study of Statistical Models

    Science.gov (United States)

    Xiao, Chenyang; McCright, Aaron M.

    2007-01-01

    Studies of the social bases of environmental concern over the past 30 years have produced somewhat inconsistent results regarding the effects of sociodemographic variables, such as gender, income, and place of residence. The authors argue that model specification errors resulting from violation of two statistical assumptions (interval-level…

  1. Novel Dodecaarylporphyrins: Synthesis and Variable Temperature NMR Studies

    Energy Technology Data Exchange (ETDEWEB)

    Cancilla, Mark; Lebrilla, Carlito; Ma, Jian-Guo; Medforth, Craig J.; Muzzi, Cinzia M.; Shelnutt, John A.; Smith, Kevin M.; Voss, Lisa

    1999-05-05

    An investigation of the synthesis of novel dodecaarylporphyrins using the Suzuki coupling reaction of arylboronic acids with octabromotetraarylporphyrins is reported. Studies of the dynamic properties of these new porphyrins using variable temperature (VT) 1H NMR spectroscopy and molecular mechanics provide interesting insights into their dynamic properties, including the first determination of {beta} aryl rotation in a porphyrin system.

  2. Variability in Rheumatology day care hospitals in Spain: VALORA study.

    Science.gov (United States)

    Hernández Miguel, María Victoria; Martín Martínez, María Auxiliadora; Corominas, Héctor; Sanchez-Piedra, Carlos; Sanmartí, Raimon; Fernandez Martinez, Carmen; García-Vicuña, Rosario

    To describe the variability of the day care hospital units (DCHUs) of Rheumatology in Spain, in terms of structural resources and operating processes. Multicenter descriptive study with data from a self-completed questionnaire of DCHUs self-assessment based on DCHUs quality standards of the Spanish Society of Rheumatology. Structural resources and operating processes were analyzed and stratified by hospital complexity (regional, general, major and complex). Variability was determined using the coefficient of variation (CV) of the variable with clinical relevance that presented statistically significant differences when was compared by centers. A total of 89 hospitals (16 autonomous regions and Melilla) were included in the analysis. 11.2% of hospitals are regional, 22,5% general, 27%, major and 39,3% complex. A total of 92% of DCHUs were polyvalent. The number of treatments applied, the coordination between DCHUs and hospital pharmacy and the post graduate training process were the variables that showed statistically significant differences depending on the complexity of hospital. The highest rate of rheumatologic treatments was found in complex hospitals (2.97 per 1,000 population), and the lowest in general hospitals (2.01 per 1,000 population). The CV was 0.88 in major hospitals; 0.86 in regional; 0.76 in general, and 0.72 in the complex. there was variability in the number of treatments delivered in DCHUs, being greater in major hospitals and then in regional centers. Nonetheless, the variability in terms of structure and function does not seem due to differences in center complexity. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  3. GENETIC VARIABILITY AND CORRELATION STUDIES IN BRINJAL (SOLANUM MELONGENA L.)

    OpenAIRE

    Bhukya Ravi Nayak; P. K. Nagre

    2013-01-01

    The present investigation was conducted at Department of Horticulture, Horticulture Garden, Dr. PDKV, Akola (M.S.), during kharif 2012-13. The experimental material comprised of 20 genotypes along with one check of brinjal and the experimental was laid out in randomized block design with three replications. Variability studies revealed that highly significant differences were recorded among the varieties for all characters. Correlation and path analysis revealed that fruit length, diameter, w...

  4. Temperature variability during delirium in ICU patients: an observational study.

    Directory of Open Access Journals (Sweden)

    Arendina W van der Kooi

    Full Text Available INTRODUCTION: Delirium is an acute disturbance of consciousness and cognition. It is a common disorder in the intensive care unit (ICU and associated with impaired long-term outcome. Despite its frequency and impact, delirium is poorly recognized by ICU-physicians and -nurses using delirium screening tools. A completely new approach to detect delirium is to use monitoring of physiological alterations. Temperature variability, a measure for temperature regulation, could be an interesting component to monitor delirium, but whether temperature regulation is different during ICU delirium has not yet been investigated. The aim of this study was to investigate whether ICU delirium is related to temperature variability. Furthermore, we investigated whether ICU delirium is related to absolute body temperature. METHODS: We included patients who experienced both delirium and delirium free days during ICU stay, based on the Confusion Assessment method for the ICU conducted by a research- physician or -nurse, in combination with inspection of medical records. We excluded patients with conditions affecting thermal regulation or therapies affecting body temperature. Daily temperature variability was determined by computing the mean absolute second derivative of the temperature signal. Temperature variability (primary outcome and absolute body temperature (secondary outcome were compared between delirium- and non-delirium days with a linear mixed model and adjusted for daily mean Richmond Agitation and Sedation Scale scores and daily maximum Sequential Organ Failure Assessment scores. RESULTS: Temperature variability was increased during delirium-days compared to days without delirium (β(unadjusted=0.007, 95% confidence interval (CI=0.004 to 0.011, p<0.001. Adjustment for confounders did not alter this result (β(adjusted=0.005, 95% CI=0.002 to 0.008, p<0.001. Delirium was not associated with absolute body temperature (β(unadjusted=-0.03, 95% CI=-0.17 to 0

  5. An Undergraduate Research Experience on Studying Variable Stars

    Science.gov (United States)

    Amaral, A.; Percy, J. R.

    2016-06-01

    We describe and evaluate a summer undergraduate research project and experience by one of us (AA), under the supervision of the other (JP). The aim of the project was to sample current approaches to analyzing variable star data, and topics related to the study of Mira variable stars and their astrophysical importance. This project was done through the Summer Undergraduate Research Program (SURP) in astronomy at the University of Toronto. SURP allowed undergraduate students to explore and learn about many topics within astronomy and astrophysics, from instrumentation to cosmology. SURP introduced students to key skills which are essential for students hoping to pursue graduate studies in any scientific field. Variable stars proved to be an excellent topic for a research project. For beginners to independent research, it introduces key concepts in research such as critical thinking and problem solving, while illuminating previously learned topics in stellar physics. The focus of this summer project was to compare observations with structural and evolutionary models, including modelling the random walk behavior exhibited in the (O-C) diagrams of most Mira stars. We found that the random walk could be modelled by using random fluctuations of the period. This explanation agreed well with observations.

  6. S5 0716+714 : GeV variability study

    CERN Document Server

    Rani, B; Lott, B; Fuhrmann, L; Zensus, J A

    2013-01-01

    The GeV observations by Fermi-LAT give us the opportunity to characterize the high-energy emission (100 MeV - 300 GeV) variability properties of the BL Lac object S5 0716+714. In this study, we performed flux and spectral analysis of more than 3 year long (August 2008 to April 2012) Fermi-LAT data of the source. During this period, the source exhibits two different modes of flux variability with characteristic timescales of ~75 and ~140 days, respectively. We also notice that the flux variations are characterized by a weak spectral hardening. The GeV spectrum of the source shows a clear deviation from a simple power law, and is better explained by a broken power law. Similar to other bright Fermi blazars, the break energy does not vary with the source flux during the different activity states. We discuss several possible scenarios to explain the observed spectral break.

  7. Multi-frequency Study of Intraday Variable Sources

    CERN Document Server

    Cim`o, G; Krichbaum, T P; Beckert, T; Kraus, A L; Witzel, A; Zensus, J A; Cim\\`o, Giuseppe

    2002-01-01

    Intraday variability (IDV) of compact extragalactic radio sources is a complex phenomenon and shows a wavelength dependent mixture of refractive interstellar scintillation (RISS) (dominant at long cm-wavelengths) and source-intrinsic effects (dominant at shorter wavelengths). Detailed investigations of individual sources and new high frequency observations suggest a source-intrinsic contribution to the IDV pattern at least in some sources. However, the sizes of intraday variable sources at cm-wavelength are typically smaller than the scattering size set by the ISM in our galaxy and scintillation must be present, too. We present new IDV observations in different regimes (from cm to sub-mm wavelengths) and show how such multi-frequency study can be used as powerful instrument to describe different aspects of IDV.

  8. Study of the variability of Blazars gamma-ray emission

    CERN Document Server

    Sbarrato, T; Ghisellini, G; Tavecchio, F

    2011-01-01

    The gamma-ray emission of blazar jets shows a pronounced variability and this feature provides limits to the size and to the speed of the emitting region. We study the gamma-ray variability of bright blazars using data from the first 18 months of activity of the Large Area Telescope on the Fermi Gamma-Ray Space Telescope. From the daily light-curves of the blazars characterized by a remarkable activity, we firstly determine the minimum variability time-scale, giving an upper limit for the size of the emitting region of the sources, assumed to be spheroidal blobs in relativistic motion. These regions must be smaller than ~10^-3 parsec. Another interesting time-scale is the duration of the outbursts. We conclude that they cannot correspond to radiation produced by a single blob moving relativistically along the jet, but they are either the signature of emission from a standing shock extracting energy from a modulated jet, or the superposition of a number of flares occurring on a shorter time-scale. We also deri...

  9. Genetic variability and correlation studies in sunflower (Helianthus annuus L.

    Directory of Open Access Journals (Sweden)

    Sheshaiah and Shankergoud I.

    2015-06-01

    Full Text Available The present study was conducted in order to investigate genetic variability and to understand the relationship and contribution of characters towards total dry matter and root length. The investigation was carried out at Main Agricultural Research Station, UAS, Raichur during Rabi 2012-13, 32 genotypes were evaluated in RBD fashion under root structures. At flowering stage all morphological and root characters were scored. The total dry matter content was assessed after drying the root, stem, leaf, petiole and flower of the plant at 70 0C in an oven.. High GCV coupled with high PCV recorded for most of the characters except stem girth, SPAD reading and number of leaves, indicating more variability for these traits and are less influenced by the environment. High heritability coupled with high GAM reported for all the traits under study suggested for the greater effectiveness for selection and improvement expected for these traits in future generations. The total dry matter and root length had very highly significant positive association with plant height, root volume, fresh root weight, dry root weight, fresh stem weight, dry stem weight, fresh leaf weight and dry leaf weight indicating the importance of root characters in determining the moisture stress tolerance and putforthing the total dry matter content of the plant.

  10. SLUDGE BATCH 5 VARIABILITY STUDY WITH FRIT 418

    Energy Technology Data Exchange (ETDEWEB)

    Raszewski, F; Tommy Edwards, T; David Peeler, D

    2008-09-29

    The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 5 (SB5) in early FY 2009. In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frit 418 as a transitional frit to initiate processing of SB5. This recommendation was based on the results of assessments on the compositional projections for SB5 available at that time from both the Liquid Waste Organization (LWO) and SRNL (using a model-based approach). To support qualification of the Frit 418-SB5 system, SRNL executed a variability study to assess the acceptability of the Frit 418-SB5 glasses with respect to durability and the applicability of the current durability models. Twenty one glasses were selected for the variability study based on the available SB5 projections primarily spanning a waste loading (WL) range of 25-37%. In order to account for the addition of caustic to Tank 40, which occurred in July 2008, 3 wt% Na2O was added to the original Tank 40 heel projections. The addition of the Actinide Removal Process (ARP) stream to the blend composition was also included. Two of the glasses were fabricated at 25% and 28% WL in order to challenge the homogeneity constraint of the Product Composition Control System (PCCS) for SB5 coupled operations. These twenty one glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD) and the Product Consistency Test (PCT). The results of this study indicate that Frit 418 is a viable option for sludge-only and coupled operations. The addition of ARP did not have any negative impacts on the acceptability and predictability of the variability study glasses. Based on the measured PCT response, all of the glasses were acceptable as compared to the Environmental Assessment (EA) reference glass regardless of the thermal history and were also predictable using the current PCCS model for durability. The homogeneity constraint can

  11. Variability in microbiological degradation experiments, analysis and case study

    DEFF Research Database (Denmark)

    Sommer, Helle Mølgaard

    1997-01-01

    of the parameter estimates are depending of the choice of estimation method, this fact has not either received much attention, all though an unsuitable estimation method can lead to estimates which are quite different from the ``true'' values. The present thesis describes various nonlinear estimation techniques...... and describes analysis techniques for testing the reproducibility of a given experiment. The parameter estimation method employed for the experiments in this study is based on an iterative maximum likelihood method and the test statistic is an approximated likelihood ratio test. The estimations were carried out...... estimation method. The examination of reproducibility/variability were carried out for two kinds of experiments: A single substrate experiment with toluene and a dual substrate experiment with toluene and benzene. A pure culture, isolated from soil, grew with benzene and/or toluene as the only carbon...

  12. Design studies of continuously variable transmissions for electric vehicles

    Science.gov (United States)

    Parker, R. J.; Loewenthal, S. H.; Fischer, G. K.

    1981-01-01

    Preliminary design studies were performed on four continuously variable transmission (CVT) concepts for use with a flywheel equipped electric vehicle of 1700 kg gross weight. Requirements of the CVT's were a maximum torque of 450 N-m (330 lb-ft), a maximum output power of 75 kW (100 hp), and a flywheel speed range of 28,000 to 14,000 rpm. Efficiency, size, weight, cost, reliability, maintainability, and controls were evaluated for each of the four concepts which included a steel V-belt type, a flat rubber belt type, a toroidal traction type, and a cone roller traction type. All CVT's exhibited relatively high calculated efficiencies (68 percent to 97 percent) over a broad range of vehicle operating conditions. Estimated weight and size of these transmissions were comparable to or less than equivalent automatic transmission. The design of each concept was carried through the design layout stage.

  13. A New Psychosocial Variable in Mental Health Studies: Agency

    Directory of Open Access Journals (Sweden)

    Hasan Atak

    2011-09-01

    Full Text Available The term agency has been defined as a sense of responsibility for one’s life course, the belief that one is in control of one’s decisions and is responsible for their outcomes, and the confidence that one will be able to overcome obstacles that impede one’s progress along one’s chosen life course. Agency is an upper psychological structure which consists of self-esteem, purpose in life, self-efficacy (ego strength, and internal locus of control. Literature offers quite different explanations for agency concept. The reason of this situation may be the attribution of different meanings to the concept by psychologists and sociologists. When considering the agency literature in Turkey and other countries, it can be said that the number of studies on agency subject is lower than the number of studies on other psychosocial study subjects. Agency should be taken into consideration as a psychosocial variable in the studies to be made in Turkey.

  14. Crystal structure of homo-DNA and nature's choice of pentose over hexose in the genetic system

    Energy Technology Data Exchange (ETDEWEB)

    Egli, Martin; Pallan, Pradeep S.; Pattanayek, Rekha; Wilds, Christopher J.; Lubini, Paolo; Minasov, George; Dobler, Max; Leumann, Christian J.; Eschenmoser, Albert (Bern); (Vanderbilt); (Scripps); (NWU); (Biographics Laboratory 3R); (Alta)

    2010-03-05

    An experimental rationalization of the structure type encountered in DNA and RNA by systematically investigating the chemical and physical properties of alternative nucleic acids has identified systems with a variety of sugar-phosphate backbones that are capable of Watson-Crick base pairing and in some cases cross-pairing with the natural nucleic acids. The earliest among the model systems tested to date, (4{prime} {yields} 6{prime})-linked oligo(2{prime},3{prime}-dideoxy-{beta}-d-glucopyranosyl)nucleotides or homo-DNA, shows stable self-pairing, but the pairing rules for the four natural bases are not the same as those in DNA. However, a complete interpretation and understanding of the properties of the hexapyranosyl (4{prime} {yields} 6{prime}) family of nucleic acids has been impeded until now by the lack of detailed 3D-structural data. We have determined the crystal structure of a homo-DNA octamer. It reveals a weakly twisted right-handed duplex with a strong inclination between the hexose-phosphate backbones and base-pair axes, and highly irregular values for helical rise and twist at individual base steps. The structure allows a rationalization of the inability of allo-, altro-, and glucopyranosyl-based oligonucleotides to form stable pairing systems.

  15. Allelic variants of hexose transporter Hxt3p and hexokinases Hxk1p/Hxk2p in strains of Saccharomyces cerevisiae and interspecies hybrids.

    Science.gov (United States)

    Zuchowska, Magdalena; Jaenicke, Elmar; König, Helmut; Claus, Harald

    2015-11-01

    The transport of sugars across the plasma membrane is a critical step in the utilization of glucose and fructose by Saccharomyces cerevisiae during must fermentations. Variations in the molecular structure of hexose transporters and kinases may affect the ability of wine yeast strains to finish sugar fermentation, even under stressful wine conditions. In this context, we sequenced and compared genes encoding the hexose transporter Hxt3p and the kinases Hxk1p/Hxk2p of Saccharomyces strains and interspecies hybrids with different industrial usages and regional backgrounds. The Hxt3p primary structure varied in a small set of amino acids, which characterized robust yeast strains used for the production of sparkling wine or to restart stuck fermentations. In addition, interspecies hybrid strains, previously isolated at the end of spontaneous fermentations, revealed a common amino acid signature. The location and potential influence of the amino acids exchanges is discussed by means of a first modelled Hxt3p structure. In comparison, hexokinase genes were more conserved in different Saccharomyces strains and hybrids. Thus, molecular variants of the hexose carrier Hxt3p, but not of kinases, correlate with different fermentation performances of yeast.

  16. Identification of Selective Inhibitors of the Plasmodium falciparum Hexose Transporter PfHT by Screening Focused Libraries of Anti-Malarial Compounds.

    Directory of Open Access Journals (Sweden)

    Diana Ortiz

    Full Text Available Development of resistance against current antimalarial drugs necessitates the search for novel drugs that interact with different targets and have distinct mechanisms of action. Malaria parasites depend upon high levels of glucose uptake followed by inefficient metabolic utilization via the glycolytic pathway, and the Plasmodium falciparum hexose transporter PfHT, which mediates uptake of glucose, has thus been recognized as a promising drug target. This transporter is highly divergent from mammalian hexose transporters, and it appears to be a permease that is essential for parasite viability in intra-erythrocytic, mosquito, and liver stages of the parasite life cycle. An assay was developed that is appropriate for high throughput screening against PfHT based upon heterologous expression of PfHT in Leishmania mexicana parasites that are null mutants for their endogenous hexose transporters. Screening of two focused libraries of antimalarial compounds identified two such compounds that are high potency selective inhibitors of PfHT compared to human GLUT1. Additionally, 7 other compounds were identified that are lower potency and lower specificity PfHT inhibitors but might nonetheless serve as starting points for identification of analogs with more selective properties. These results further support the potential of PfHT as a novel drug target.

  17. A comparative study of pulse rate variability and heart rate variability in healthy subjects.

    Science.gov (United States)

    Wong, Jih-Sen; Lu, Wan-An; Wu, Kung-Tai; Liu, Margaret; Chen, Gau-Yang; Kuo, Cheng-Deng

    2012-04-01

    Both heart rate variability (HRV) and pulse rate variability (PRV) are noninvasive means for the assessment of autonomic nervous control of the heart. However, it is not settled whether or not the PRV obtained from either hand can be the surrogate of HRV. The HRV measures obtained from electrocardiographic signals and the PRV measures obtained from the pulse waves recorded from the index fingers of both hands were compared in normal subjects by using linear regression analysis and Bland and Altman method. Highly significant correlations (P < 0.001, 0.89 < r < 1.0) were found between all HRV measures and the corresponding PRV measures of both hands. However, there were insufficient agreements in some measures between pairwise comparisons among HRV, right PRV and left PRV except heart rate and ultra-low frequency power (ULFP). The PRV of either hand is close to, but not the same as the HRV in healthy subjects. The HRV, right PRV and left PRV are not surrogates of one another in normal subjects except heart rate and ULFP. Since HRV is generally accepted as the standard method for the assessment of the autonomic nervous modulation of a subject, the PRV of either hand may not be suitable for the assessment of the cardiac autonomic nervous modulation of the subject.

  18. Climate variability and campylobacter infection: an international study

    Science.gov (United States)

    Sari Kovats, R.; Edwards, Sally J.; Charron, Dominique; Cowden, John; D'Souza, Rennie M.; Ebi, Kristie L.; Gauci, Charmaine; Gerner-Smidt, Peter; Hajat, Shakoor; Hales, Simon; Hernández Pezzi, Gloria; Kriz, Bohumir; Kutsar, Kuulo; McKeown, Paul; Mellou, Kassiani; Menne, Bettina; O'Brien, Sarah; Pelt, Wilfrid; Schmid, Hans

    2005-03-01

    Campylobacter is among the most important agents of enteritis in developed countries. We have described the potential environmental determinants of the seasonal pattern of infection with campylobacter in Europe, Canada, Australia and New Zealand. Specifically, we investigated the role of climate variability on laboratory-confirmed cases of campylobacter infection from 15 populations. Regression analysis was used to quantify the associations between timing of seasonal peaks in infection in space and time. The short-term association between weekly weather and cases was also investigated using Poisson regression adapted for time series data. All countries in our study showed a distinct seasonality in campylobacter transmission, with many, but not all, populations showing a peak in spring. Countries with milder winters have peaks of infection earlier in the year. The timing of the peak of infection is weakly associated with high temperatures 3 months previously. Weekly variation in campylobacter infection in one region of the UK appeared to be little affected by short-term changes in weather patterns. The geographical variation in the timing of the seasonal peak suggests that climate may be a contributing factor to campylobacter transmission. The main driver of seasonality of campylobacter remains elusive and underscores the need to identify the major serotypes and routes of transmission for this disease.

  19. Temperature Variability and Mortality: A Multi-Country Study

    Science.gov (United States)

    Guo, Yuming; Gasparrini, Antonio; Armstrong, Ben G.; Tawatsupa, Benjawan; Tobias, Aurelio; Lavigne, Eric; Coelho, Micheline de Sousa Zanotti Stagliorio; Pan, Xiaochuan; Kim, Ho; Hashizume, Masahiro; Honda, Yasushi; Guo, Yue Leon; Wu, Chang-Fu; Zanobetti, Antonella; Schwartz, Joel D.; Bell, Michelle L.; Overcenco, Ala; Punnasiri, Kornwipa; Li, Shanshan; Tian, Linwei; Saldiva, Paulo; Williams, Gail; Tong, Shilu

    2016-01-01

    G, Tong S. 2016. Temperature variability and mortality: a multi-country study. Environ Health Perspect 124:1554–1559; http://dx.doi.org/10.1289/EHP149 PMID:27258598

  20. Hexose-6-phosphate dehydrogenase contributes to skeletal muscle homeostasis independent of 11β-hydroxysteroid dehydrogenase type 1.

    LENUS (Irish Health Repository)

    Semjonous, Nina M

    2011-01-01

    Glucose-6-phosphate (G6P) metabolism by the enzyme hexose-6-phosphate dehydrogenase (H6PDH) within the sarcoplasmic reticulum lumen generates nicotinamide adenine dinucleotide phosphate (reduced) to provide the redox potential for the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) to activate glucocorticoid (GC). H6PDH knockout (KO) mice have a switch in 11β-HSD1 activity, resulting in GC inactivation and hypothalamic-pituitary-adrenal axis activation. Importantly, H6PDHKO mice develop a type II fiber myopathy with abnormalities in glucose metabolism and activation of the unfolded protein response (UPR). GCs play important roles in muscle physiology, and therefore, we have examined the importance of 11β-HSD1 and GC metabolism in mediating aspects of the H6PDHKO myopathy. To achieve this, we examined 11β-HSD1\\/H6PDH double-KO (DKO) mice, in which 11β-HSD1 mediated GC inactivation is negated. In contrast to H6PDHKO mice, DKO mice GC metabolism and hypothalamic-pituitary-adrenal axis set point is similar to that observed in 11β-HSD1KO mice. Critically, in contrast to 11β-HSD1KO mice, DKO mice phenocopy the salient features of the H6PDHKO, displaying reduced body mass, muscle atrophy, and vacuolation of type II fiber-rich muscle, fasting hypoglycemia, increased muscle glycogen deposition, and elevated expression of UPR genes. We propose that muscle G6P metabolism through H6PDH may be as important as changes in the redox environment when considering the mechanism underlying the activation of the UPR and the ensuing myopathy in H6PDHKO and DKO mice. These data are consistent with an 11β-HSD1-independent function for H6PDH in which sarcoplasmic reticulum G6P metabolism and nicotinamide adenine dinucleotide phosphate-(oxidized)\\/nicotinamide adenine dinucleotide phosphate (reduced) redox status are important for maintaining muscle homeostasis.

  1. Xylose and xylose/glucose co-fermentation by recombinant Saccharomyces cerevisiae strains expressing individual hexose transporters.

    Science.gov (United States)

    Gonçalves, Davi L; Matsushika, Akinori; de Sales, Belisa B; Goshima, Tetsuya; Bon, Elba P S; Stambuk, Boris U

    2014-09-01

    Since the uptake of xylose is believed to be one of the rate-limiting steps for xylose ethanol fermentation by recombinant Saccharomyces cerevisiae strains, we transformed a hxt-null strain lacking the major hexose transporters (hxt1Δ-hxt7Δ and gal2Δ) with an integrative plasmid to overexpress the genes for xylose reductase (XYL1), xylitol dehydrogenase (XYL2) and xylulokinase (XKS1), and analyzed the impact that overexpression of the HXT1, HXT2, HXT5 or HXT7 permeases have in anaerobic batch fermentations using xylose, glucose, or xylose plus glucose as carbon sources. Our results revealed that the low-affinity HXT1 permease allowed the maximal consumption of sugars and ethanol production rates during xylose/glucose co-fermentations, but was incapable to allow xylose uptake when this sugar was the only carbon source. The moderately high-affinity HXT5 permease was a poor glucose transporter, and it also did not allow significant xylose uptake by the cells. The moderately high-affinity HXT2 permease allowed xylose uptake with the same rates as those observed during glucose consumption, even under co-fermentation conditions, but had the drawback of producing incomplete fermentations. Finally, the high-affinity HXT7 permease allowed efficient xylose fermentation, but during xylose/glucose co-fermentations this permease showed a clear preference for glucose. Thus, our results indicate that approaches to engineer S. cerevisiae HXT transporters to improve second generation bioethanol production need to consider the composition of the biomass sugar syrup, whereby the HXT1 transporter seems more suitable for hydrolysates containing xylose/glucose blends, whereas the HXT7 permease would be a better choice for xylose-enriched sugar streams.

  2. Spectroscopic study of the variability of three northern Of+ supergiants

    CERN Document Server

    De Becker, M; Linder, N

    2009-01-01

    The transition from early Of stars to WN type objects is poorly understood. O-type supergiants with emission lines (OIf+) are considered to be intermediate between these two classes. The scope of this paper is to investigate the spectral variability of three Of+ supergiants. We constituted spectral time series of unprecedented quality for our targets (~ 200 spectra in total), essentially in the blue domain, covering time-scales from a few hours up to a few years. Time Variance Spectrum (TVS) and Fourier analyses were performed in order to characterize their spectral variability. We report on a correlated significant line profile variability in the prominent He II \\lambda 4686 and H\\beta lines most likely related to the strong stellar winds. The variability pattern is similar for the three stars investigated (HD14947, HD15570 and HD16691), and the main differences are more quantitative than qualitative. However, the reported time-scales are somewhat different, and the most striking variability pattern is repor...

  3. Inter-reader variability in alternate forced choice studies

    Science.gov (United States)

    Huda, W.; Ogden, K. M.; Samei, E.; Scalzetti, E. M.; Lavallee, R. L.; Roskopf, M. L.

    2008-03-01

    In this study, we investigated differences in detection performance for twelve observers who each generated a CT contrast detail curve. An anthropomorphic newborn phantom's abdomen was imaged using a GE Light Speed CT scanner (4-slice). Alternate Forced Choice (AFC) experiments were performed with lesions sizes ranging from 2.5 to 12.5 mm to determine the intensity needed to achieve 92% correct (I 92%). Following training, twelve readers consisting of (2 technologists, 4 college students, 4 medical students, and 2 radiology residents) generated a single contrast detail curve. Eight readers produced approximately linear contrast detail curves while the remaining four readers required a second order polynomial fit because of reduced performance when detecting the largest (i.e., 12.5 mm) lesion. For the three smallest lesions, the coefficient of variation between the twelve readers was ~12%, which increases with increasing lesion size to ~23% for 12.5 mm lesion size. The ratio of the maximum I 92% to minimum I 92% values was ~1.6 for the smallest lesions, which increased to a factor of ~2.1 for the 12.5 mm lesion. Our results show that minimizing inter-reader variability in our AFC experiments could be achieved by eliminating the largest lesion that cause detection problems in one third of observers. The combined experimental data showed that the slope of the contrast detail curve was -0.42, lower than the value of -1.0 predicted by the Rose model, suggesting that the noise texture in CT associated with both quantum mottle and anatomic structure is an important factor affecting detection of these lesions.

  4. Hexose-6-phosphate dehydrogenase modulates 11beta-hydroxysteroid dehydrogenase type 1-dependent metabolism of 7-keto- and 7beta-hydroxy-neurosteroids.

    Directory of Open Access Journals (Sweden)

    Lyubomir G Nashev

    Full Text Available BACKGROUND: The role of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1 in the regulation of energy metabolism and immune system by locally reactivating glucocorticoids has been extensively studied. Experiments determining initial rates of enzyme activity revealed that 11beta-HSD1 can catalyze both the reductase and the dehydrogenase reaction in cell lysates, whereas it predominantly catalyzes the reduction of cortisone to cortisol in intact cells that also express hexose-6-phosphate dehydrogenase (H6PDH, which provides cofactor NADPH. Besides its role in glucocorticoid metabolism, there is evidence that 11beta-HSD1 is involved in the metabolism of 7-keto- and 7-hydroxy-steroids; however the impact of H6PDH on this alternative function of 11beta-HSD1 has not been assessed. METHODOLOGY: We investigated the 11beta-HSD1-dependent metabolism of the neurosteroids 7-keto-, 7alpha-hydroxy- and 7beta-hydroxy-dehydroepiandrosterone (DHEA and 7-keto- and 7beta-hydroxy-pregnenolone, respectively, in the absence or presence of H6PDH in intact cells. 3D-structural modeling was applied to study the binding of ligands in 11beta-HSD1. PRINCIPAL FINDINGS: We demonstrated that 11beta-HSD1 functions in a reversible way and efficiently catalyzed the interconversion of these 7-keto- and 7-hydroxy-neurosteroids in intact cells. In the presence of H6PDH, 11beta-HSD1 predominantly converted 7-keto-DHEA and 7-ketopregnenolone into their corresponding 7beta-hydroxy metabolites, indicating a role for H6PDH and 11beta-HSD1 in the local generation of 7beta-hydroxy-neurosteroids. 3D-structural modeling offered an explanation for the preferred formation of 7beta-hydroxy-neurosteroids. CONCLUSIONS: Our results from experiments determining the steady state concentrations of glucocorticoids or 7-oxygenated neurosteroids suggested that the equilibrium between cortisone and cortisol and between 7-keto- and 7-hydroxy-neurosteroids is regulated by 11beta-HSD1 and greatly

  5. John Goodricke, Edward Pigott, and Their Study of Variable Stars

    CERN Document Server

    French, L M

    2012-01-01

    John Goodricke and Edward Pigott, working in York, England, between 1781 and 1786, determined the periods of variation of eclipsing binaries such as Algol and Beta Lyrae and speculated that the eclipses of Algol might be caused by a "dark body," perhaps even a planet. They also determined the periods of variation of the first two known Cepheid variables, the stars whose period-luminosity relation today enables astronomers to determine distances to distant galaxies. Goodricke holds special interest because he was completely deaf and because he died at the age of 21. The lives and work of these two astronomers are described.

  6. A weather type method to study surface ocean variables

    Science.gov (United States)

    Menendez, M.; Camus, P.; Mendez, F. J.; Losada, I. J.

    2012-04-01

    The set of methodologies for obtaining wave climate information at high spatial resolution from relatively coarse resolution is known as downscaling. Dynamic downscaling, based on the use of numerical models, is perhaps the most widely used methodology for surface ocean variables. An alternative approach is the statistical downscaling, that can be conducted by means of regression methods or weather pattern-based approaches. The main advantages of the statistical downscaling based on weather patterns are: the low computational requirements; the ease of implementation; the additional climatology information; and local forecast application. Moreover, this technique allows exploring the synoptic atmospheric climatology and their relationship with surface ocean variables. It is well known nowadays that the seasonal-to-interannual variability of wave climate is linked to the atmosphere circulation patterns. We proposed a statistical approach based on the predictand (eg. local wave characteristics) is associated to a particular synoptic-scale weather type (predictor). The predictor is the n-days-averaged sea level pressure field (SLP) anomalies, which are synthesized using data mining techniques to describe a number of weather types. In particular, we focus in NE Atlantic (NAO region) using as predictor the 3-days-averaged SLP fields calculated by NCEP atmospheric reanalysis (1948-2010). A principal component analysis is applied over SLP fields to reduce the spatial and temporal dimensions. The K-means clustering technique is then applied to the two-dimensional sample of the principal components which explain more than 95% variance of the SLP. The K-means technique divides the data space into a number of clusters, where each of them is characterized by a centroid and formed by the data for which the centroid is the nearest. Finally, we visualize the weather types associated to each centroid in an ordered way similar to self-organizing maps, SOMs. The probability

  7. Toroidal Continuously Variable Transmission Systems: Terminology and Present Studies

    Directory of Open Access Journals (Sweden)

    Ahmet YILDIZ

    2014-04-01

    Full Text Available The use of continuously variable transmission systems in many different areas such as aerospace, robotics, machinery and automotive industries as an alternative to conventional speed changers with constant ratio becomes widely.Especially in the automotive industry, these systems have been used increasingly, since they enable that internal combustion engines in vehicles run at optimal speeds, and consequently provide considerable fuel savings and therefore lower emission values and also they provide powerful acceleration and quiet working. CVT systems have several constructive variants such as belted, chained, balled, toroidal etc. In this paper, toroidal CVT systems based on elastohydrodynamic principles are concerned with, and fundamental works of last two decades in this field are reviewed. However, the relevant terminology and dynamics along with the control of these systems are briefly treated for better understanding of the literature mentioned. Attention is drawn to the lack of some significant issues in present research works, and potential future works are pointed out. This paper, to the authors’ knowledge, will be the first review on toroidal CVT systems in Turkish literature

  8. Design Study for Direction Variable Compton Scattering Gamma Ray

    Science.gov (United States)

    Kii, T.; Omer, M.; Negm, H.; Choi, Y. W.; Kinjo, R.; Yoshida, K.; Konstantin, T.; Kimura, N.; Ishida, K.; Imon, H.; Shibata, M.; Shimahashi, K.; Komai, T.; Okumura, K.; Zen, H.; Masuda, K.; Hori, T.; Ohgaki, H.

    2013-03-01

    A monochromatic gamma ray beam is attractive for isotope-specific material/medical imaging or non-destructive inspection. A laser Compton scattering (LCS) gamma ray source which is based on the backward Compton scattering of laser light on high-energy electrons can generate energy variable quasi-monochromatic gamma ray. Due to the principle of the LCS gamma ray, the direction of the gamma beam is limited to the direction of the high-energy electrons. Then the target object is placed on the beam axis, and is usually moved if spatial scanning is required. In this work, we proposed an electron beam transport system consisting of four bending magnets which can stick the collision point and control the electron beam direction, and a laser system consisting of a spheroidal mirror and a parabolic mirror which can also stick the collision point. Then the collision point can be placed on one focus of the spheroid. Thus gamma ray direction and collision angle between the electron beam and the laser beam can be easily controlled. As the results, travelling direction of the LCS gamma ray can be controlled under the limitation of the beam transport system, energy of the gamma ray can be controlled by controlling incident angle of the colliding beams, and energy spread can be controlled by changing the divergence of the laser beam.

  9. STUDY OF GENETIC VARIABILITY OF TRITICALE VARIETIES BY SSR MARKERS

    Directory of Open Access Journals (Sweden)

    Jana Ondroušková

    2013-04-01

    Full Text Available For the detection of genetic variability ten genotypes of winter triticale (×Triticosecale Wittmack, 2n = 6x = 42; BBAARR were selected: nine varieties and one breeding line with good bread-making quality KM 4-09 with the chromosome translocation 1R.1D 5+10-2. 25 microsatellites markers located in the genome A, B, D and R were chosen for analysis. Eighty-four alleles were detected with an average of 3.36 alleles per locus were detected. For each microsatellite statistical values were calculated diversity index (DI, probabilities of identity (PI and polymorphic information content (PIC were calculated and averages statistical values are: DI 0.55, PI 0.27 and 0.5 PIC. Overall dendrogram based on the UPGMA method (Jaccards similarity coefficient significantly distinguished two groups of genotypes and these groups were divided into sub-clusters. A set of 5 SSR markers (Xwms0752, Xbarc128, Xrems1237, Xwms0861 and Xbrac170 which have the calculated PIC value higher than 0.68 that are sufficient for the identification of the analyzed genotypes was described.

  10. Characterization of the RokA and HexA broad-substrate-specificity hexokinases from Bacteroides fragilis and their role in hexose and N-acetylglucosamine utilization.

    Science.gov (United States)

    Brigham, Christopher J; Malamy, Michael H

    2005-02-01

    Bacteroides fragilis, a human gastrointestinal commensal and an opportunistic pathogen, utilizes simple and complex sugars and polysaccharides for growth in the large intestine and at sites of infection. Because B. fragilis lacks transport-linked sugar phosphorylation systems, cytoplasmic kinase(s) was expected to be required for the phosphorylation of hexoses and hexosamines. We have now identified two hexose kinases that are important for growth of B. fragilis on glucose, mannose, and other sugars. One kinase (RokA), a member of the ROK family of proteins, was found to be the sole kinase for activation of N-acetyl-D-glucosamine (NAG). The other kinase (HexA) is responsible for the majority of the glucose kinase activity in the cell, although a hexA deletion mutant strain was not defective for growth on any substrate tested. Deletion of both the rokA and hexA kinase genes resulted in inability of the cell to use glucose, mannose, NAG, and many other sugars. We purified RokA and determined its approximate molecular mass to be 36.5 kDa. The purified RokA protein was shown to phosphorylate several substrates, including glucose, NAG, and mannose, but not N-acetylmannosamine or N-acetylneuraminic acid. Phylogenetic analysis of RokA showed that it is most similar to kinases from the Cytophaga-Flavibacterium-Bacteroides group, while HexA was most similar to other bacterial hexokinases and eukaryotic hexokinases.

  11. New Swift UVOT data reduction tools and AGN variability studies

    Science.gov (United States)

    Gelbord, Jonathan; Edelson, Rick

    2017-08-01

    The efficient slewing and flexible scheduling of the Swift observatory have made it possible to conduct monitoring campaigns that are both intensive and prolonged, with multiple visits per day sustained over weeks and months. Recent Swift monitoring campaigns of a handful of AGN provide simultaneous optical, UV and X-ray light curves that can be used to measure variability and interband correlations on timescales from hours to months, providing new constraints for the structures within AGN and the relationships between them. However, the first of these campaigns, thrice-per-day observations of NGC 5548 through four months, revealed anomalous dropouts in the UVOT light curves (Edelson, Gelbord, et al. 2015). We identified the cause as localized regions of reduced detector sensitivity that are not corrected by standard processing. Properly interpreting the light curves required identifying and screening out the affected measurements.We are now using archival Swift data to better characterize these low sensitivity regions. Our immediate goal is to produce a more complete mapping of their locations so that affected measurements can be identified and screened before further analysis. Our longer-term goal is to build a more quantitative model of the effect in order to define a correction for measured fluxes, if possible, or at least to put limits on the impact upon any observation. We will combine data from numerous background stars in well-monitored fields in order to quantify the strength of the effect as a function of filter as well as location on the detector, and to test for other dependencies such as evolution over time or sensitivity to the count rate of the target. Our UVOT sensitivity maps and any correction tools will be provided to the community of Swift users.

  12. Reduction of adverse effects by a mushroom product, active hexose correlated compound (AHCC) in patients with advanced cancer during chemotherapy--the significance of the levels of HHV-6 DNA in saliva as a surrogate biomarker during chemotherapy.

    Science.gov (United States)

    Ito, Toshinori; Urushima, Hayato; Sakaue, Miki; Yukawa, Sayoko; Honda, Hatsumi; Hirai, Kei; Igura, Takumi; Hayashi, Noriyuki; Maeda, Kazuhisa; Kitagawa, Toru; Kondo, Kazuhiro

    2014-01-01

    Chemotherapy improves the outcome of cancer treatment, but patients are sometimes forced to discontinue chemotherapy or drop out of a clinical trial due to adverse effects, such as gastrointestinal disturbances and suppression of bone marrow function. The objective of this study was to evaluate the safety and effectiveness of a mushroom product, active hexose correlated compound (AHCC), on chemotherapy-induced adverse effects and quality of life (QOL) in patients with cancer. Twenty-four patients with cancer received their first cycle of chemotherapy without AHCC and then received their second cycle with AHCC. During chemotherapy, we weekly evaluated adverse effects and QOL via a blood test, EORTC QLQ-C30 questionnaire, and DNA levels of herpes virus type 6 (HHV-6) in saliva. The DNA levels of HHV-6 were significantly increased after chemotherapy. Interestingly, administration of AHCC significantly decreased the levels of HHV-6 in saliva during chemotherapy and improved not only QOL scores in the EORTC QLQ-C30 questionnaire but also hematotoxicity and hepatotoxicity. These findings suggest that salivary HHV-6 levels may be a good biomarker of QOL in patients during chemotherapy, and that AHCC may have a beneficial effect on chemotherapy-associated adverse effects and QOL in patients with cancer undergoing chemotherapy.

  13. STUDY OF VARIABLES ASSOCIATED WITH FINAL GRADES IN MATHEMATICS COURSES.

    Science.gov (United States)

    DAVIS, ELTON C.; RISSER, JOHN J.

    THIS STUDY WAS CONDUCTED IN ORDER TO DETERMINE THE RELATIVE VALUE OF PREVIOUS GRADES IN MATHEMATICS COURSES, THE OVERALL HIGH SCHOOL GRADE POINT AVERAGE, AND THE PLACEMENT TEST IN MATHEMATICS DEVELOPED AT THE COLLEGE AS PREDICTORS OF ACHIEVEMENT IN INTRODUCTORY AND INTERMEDIATE ALGEBRA, IN COLLEGE ALGEBRA, IN TRIGONOMETRY, AND IN ANALYTIC GEOMETRY…

  14. Intra-Sensor Variability Study of two BLS 900 Scintillometers

    Science.gov (United States)

    Thiem, Christina; Mauder, Matthias; Chwala, Christian; Bernhardt, Matthias; Kunstmann, Harald; Schulz, Karsten

    2017-04-01

    The latent heat flux is an important validation parameter for satellite measurements and a wide variety of hydrological and meteorological numerical models. Scintillometers can provide references for such validations due to their ability to spatially integrate turbulent fluxes. Large-aperture near-infrared scintillometers are capable of determining spatial averages of the structure parameter of temperature and the sensible heat flux over path lengths up to 5 km. One way to derive both sensible and latent heat flux is to use a combined optical and microwave scintillometer system. With only an optical scintillometer and additional measurements of ground heat flux and net radiation, the latent heat flux can be calculated from the residual of the energy balance. Studies have shown, however, that in certain cases measurements from the same types of scintillometers differ due to minute differences in construction. In order to prove the robustness of the measurements of two near-infrared scintillometers for future studies, we compared their observations and validated them by comparison to the sensible heat flux derived from an eddy covariance system. In this study two boundary layer scintillometers (BLS; BLS900, Scintec, Rottenburg, Germany) were installed in a central European valley as part of the TERENO preAlpine observatory during the years 2013 and 2015. An independent measurement of the sensible and latent heat flux was obtained from a permanent eddy covariance system installed in the vicinity of the scintillometer path. The structure parameter of the refractive index and average sensible heat fluxes of both BLS units were compared with each other. In general, the BLS structure parameters correlated very well and the high correlation between the BLS-derived sensible heat fluxes and the eddy covariance-derived sensible heat fluxes encouraged further application of these scintillometers in separate experiments.

  15. Variable selection under multiple imputation using the bootstrap in a prognostic study

    NARCIS (Netherlands)

    Heymans, M.W.; Buuren, S. van; Knol, D.L.; Mechelen, W. van; Vet, H.C.W. de

    2007-01-01

    Background. Missing data is a challenging problem in many prognostic studies. Multiple imputation (MI) accounts for imputation uncertainty that allows for adequate statistical testing. We developed and tested a methodology combining MI with bootstrapping techniques for studying prognostic variable s

  16. Sea surface temperature variability over North Indian Ocean - A study of two contrasting monsoon seasons

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Sathyendranath, S.; Viswambharan, N.K.; Rao, L.V.G.

    Using the satellite derived sea surface temperature (SST) data for 1979 (bad monsoon) and 1983 (good monsoon), the SST variability for two contrasting monsoon seasons is studied. The study indicates that large negative anomalies off the Somali...

  17. Variable selection under multiple imputation using the bootstrap in a prognostic study

    NARCIS (Netherlands)

    Heymans, M.W.; Buuren, S. van; Knol, D.L.; Mechelen, W. van; Vet, H.C.W. de

    2007-01-01

    Background. Missing data is a challenging problem in many prognostic studies. Multiple imputation (MI) accounts for imputation uncertainty that allows for adequate statistical testing. We developed and tested a methodology combining MI with bootstrapping techniques for studying prognostic variable s

  18. Variability Study of the SX Phoenicis Star BL Camelopardalis

    Institute of Scientific and Technical Information of China (English)

    Jian-Ning Fu; Chao Zhang; Kanokwan Marak; Chayan Boonyarak; Pongsak Khokhuntod; Shi-Yang Jiang

    2008-01-01

    New time-series photometric observations of BL Cam in the V band and white light were made during 2005 to 2007 at the Xinglong Station of China. The frequency analysis confirms two closely separated frequencies, 25.181 d-1 and 25.571 d-1, but the frequency of 31-32 d-1 reported in the literature was not detected in the new data. New times of maximum light were determined from both our light curves and those available on Internet, allowing a more comprehensive study of the O - C diagram, together with the times of maximum light in the literature. A new interpretation, including the period increasing before 1988 and decreasing since 1992 of BL Cam and the light-time effect in a binary system, looks plausible.

  19. Variability Study of the SX Phoenicis Star BL Camelopardalis

    Science.gov (United States)

    Fu, Jian-Ning; Zhang, Chao; Marak, Kanokwan; Boonyarak, Chayan; Khokhuntod, Pongsak; Jiang, Shi-Yang

    2008-04-01

    New time-series photometric observations of BL Cam in the V band and white light were made during 2005 to 2007 at the Xinglong Station of China. The frequency analysis confirms two closely separated frequencies, 25.181 d-1 and 25.571 d-1, but the frequency of 31-32 d-1 reported in the literature was not detected in the new data. New times of maximum light were determined from both our light curves and those available on Internet, allowing a more comprehensive study of the O-C diagram, together with the times of maximum light in the literature. A new interpretation, including the period increasing before 1988 and decreasing since 1992 of BL Cam and the light-time effect in a binary system, looks plausible.

  20. Who Seeks Career Counselling? A Prospective Study of Personality and Career Variables among Swiss Adolescents

    Science.gov (United States)

    Balin, Elif; Hirschi, Andreas

    2010-01-01

    This study investigated whether career adaptability, personality, attitude towards career counselling and some demographic variables predict the help seeking behaviour in career counselling among 330 Swiss adolescents in eighth grade. The results indicated that boys were less likely to seek help and that career related variables and attitude but…

  1. The Impacts of the Interannual Variability of Vegetation on the Interannual Variability of Global Evapotranspiration: A Modeling Study

    Institute of Scientific and Technical Information of China (English)

    CHEN Hao; ZENG Xiao-Dong

    2012-01-01

    The impact of the interannual variability (IAV) of vegetation on the IAV of evapotranspiration is investigated with the Community Land Model (CLM3.0) and modified Dynamic Global Vegetation Model (DGVM). Two sets of 50-year off-line simulations are used in this study. The simulations begin with the same initial surface-water and heat states and are driven by the same atmospheric forcing data. The vegetation exhibits interannual variability in one simulation but not in the other simulation. However, the climatological means for the vegetation are the same. The IAV of the 50-year annual total evapotranspiration and its three partitions (ground evaporation, canopy evaporation, and transpiration) are analyzed. The global distribution of the evapotranspiration IAV and the statistics of evapotranspiration and its components in different ecosystems show that the IAV of ground evaporation is generally large in areas dominated by grass and deciduous trees, whereas the IAV of canopy evaporation and transpiration is large in areas dominated by bare soil and shrubs. For ground evaporation, canopy evaporation, and transpiration, the changes in IAV are larger than the mean state over most grasslands and shrublands. The study of two sites with the same IAV in the leaf area index (LAI) shows that the component with the smaller contribution to the total evapotranspiration is more sensitive to the IAV of vegetation. The IAV of the three components of evapotranspiration increases with the IAV of the fractional coverage (FC) and the LAI. The ground evaporation IAV shows the greatest increase, whereas the canopy evaporation shows the smallest increase.

  2. Study on the spatiotemporal variability and affecting factors in soil moisture at a humid area

    Science.gov (United States)

    Liu, H.; Yu, Z.

    2008-12-01

    The spatiotemporal variability of soil moisture and its affecting factors in a humid area were examined based on the field measuring date in the Tai lake drainage basin, China. 24 sensors near the soil surface and 12 sensors in 2 profiles (6 in each) were set up for collecting hourly soil moisture data with the Frequency Domain Reflectometry (FDR) sensors in 2006. Coefficient of variation (CV) and semi-variogram were calculated to evaluate the temporal variability in different locations and the spatial variability in different periods. The surface soil moisture appears middle or weak variability, and most of the CV values are in the range of 0.13-0.26. Soil characteristics, topography, vegetation, meteorological factors and human activities influenced the soil moisture spatiotemporal variability significantly. The factors appear having different affecting abilities on the spatiotemporal variability, and the domain factors are different in four seasons. Soil characteristics mainly influence the temporal variability in the scale of hill slope. Coarser texture on the upper part of the slope results in a larger variability. Topography and micro-topography affects the spatial variability in all 3 dimensions. The variability is larger at upper locations and chine of the slope. The effect of vegetation on the soil moisture variability is stronger in spring, summer, and autumn than in winter, according to the different growth activities and water demand. The trees on the slope influence the CV values along the slope. Meteorological factors are the forcing factors of the soil water variation. Higher rainfall and evaporation variations produce higher variability in soil moisture while the rainfall has more influence in the summer and the evaporation has more in the fall. The results provide better understanding of soil moisture variation and base for further study on how the soil moisture variation could affect the rainfall runoff partitioning.

  3. Study of formulation variables on properties of glipizide mucoadhesive microspheres by factorial design

    OpenAIRE

    Hosmani A.H; Kasture, P. V.; ID Gonjari; A.B. Karmarkar

    2009-01-01

    "nBackground and the Purpose of the study:The purpose of the study was formulate and systemsystematic evaluation in-vitro and in-vivo behaviour of Glipizide mucoadhesive microspheres using 32 full factorial design. "nMethods:Concentration of Polycarbophil and Sodium Alginate were selected as independent variables and the effects were checked on dependent variables like swelling index, mucoadhesion, drug entrapment efficiency and T75. In vivo studies were also performed to determine ...

  4. Functional characterization and expression analysis of cucumber (Cucumis sativus L.) hexose transporters, involving carbohydrate partitioning and phloem unloading in sink tissues.

    Science.gov (United States)

    Cheng, Jin-Tao; Li, Xiang; Yao, Feng-Zhen; Shan, Nan; Li, Ya-Hui; Zhang, Zhen-Xian; Sui, Xiao-Lei

    2015-08-01

    Many hexose transporters (HTs) have been reported to play roles in sucrose-transporting plants. However, little information about roles of HTs in RFOs (raffinose family oligosaccharides)-transporting plants has been reported. Here, three hexose transporters (CsHT2, CsHT3, and CsHT4) were cloned from Cucumis sativus L. Heterologous expression in yeast demonstrated that CsHT3 transported glucose, galactose and mannose, with a K(m) of 131.9 μM for glucose, and CsHT4 only transported galactose, while CsHT2 was non-functional. Both CsHT3 and CsHT4 were targeted to the plasma membrane of cucumber protoplasts. Spatio-temporal expression indicated that transcript level of CsHT3 was much higher than that of CsHT2 and CsHT4 in most tissues, especially in peduncles and fruit tissues containing vascular bundles. GUS staining of CsHT3-promoter-β-glucuronidase (GUS) transgenic Arabidopsis plants revealed CsHT3 expression in tissues with high metabolic turnover, suggesting that CsHT3 is involved in sugar competition among different sink organs during plant development. The transcript levels of CsHT3 and cell wall invertase genes increased in peduncles and fruit tissues along with cucumber fruit enlargement, and CsHT3 localized to phloem tissues by immunohistochemical localization; These results suggest that CsHT3 probably plays an important role in apoplastic phloem unloading of cucumber fruit.

  5. An Investigation of Student Teachers' Study Strategies with Respect to Certain Variables

    Science.gov (United States)

    Erdamar, Gurcu

    2011-01-01

    This study aimed to determine the study strategies of student teachers attending vocational education faculties and whether these habits are affected by certain variables (department, year of study, positive perception of university and lecturer, time spent studying). The study sample consisted of a total of 746 student teachers from 5…

  6. Study of the Influence of Formulation Variables in Bioadhesive Emulgels Using Response Surface Methodology

    National Research Council Canada - National Science Library

    Ochoa-Andrade, Ana; Parente, M Emma; Jimenez-Kairuz, Álvaro; Boinbaser, Lucía; Torregrosa, Annibal

    2017-01-01

    The aim of the present work was to study the main formulation variables that influence attributes of bioadhesive emulgels based on a combination of polymers, using response surface methodology (RSM...

  7. A Study on the Impact of Climate Variability/Change on Water Resources in the Philippines

    OpenAIRE

    1999-01-01

    This paper presents an effort toward a better understanding of the potential impact of climate variability and change on the hydrology and water resources in the Philippines. Impacts of extreme events such as droughts are discussed. A preliminary study on the variability of inflow in relation to rainfall at the major dams in Luzon and the natural water reservoir of Lake Lanao is presented. Areas for future study are also mentioned.

  8. Measurement-to-measurement blood pressure variability is related to cognitive performance: the Maine Syracuse study.

    Science.gov (United States)

    Crichton, Georgina E; Elias, Merrill F; Dore, Gregory A; Torres, Rachael V; Robbins, Michael A

    2014-11-01

    The objective was to investigate the association between variability in blood pressure (BP) and cognitive function for sitting, standing, and reclining BP values and variability derived from all 15 measures. In previous studies, only sitting BP values have been examined, and only a few cognitive measures have been used. A secondary objective was to examine associations between BP variability and cognitive performance in hypertensive individuals stratified by treatment success. Cross-sectional analyses were performed on 972 participants of the Maine Syracuse Study for whom 15 serial BP clinic measures (5 sitting, 5 recumbent, and 5 standing) were obtained before testing of cognitive performance. Using all 15 measures, higher variability in systolic and diastolic BP was associated with poorer performance on multiple measures of cognitive performance, independent of demographic factors, cardiovascular risk factors, and pulse pressure. When sitting, reclining, and standing systolic BP values were compared, only variability in standing BP was related to measures of cognitive performance. However, for diastolic BP, variability in all 3 positions was related to cognitive performance. Mean BP values were weaker predictors of cognition. Furthermore, higher overall variability in both systolic and diastolic BP was associated with poorer cognitive performance in unsuccessfully treated hypertensive individuals (with BP ≥140/90 mm Hg), but these associations were not evident in those with controlled hypertension. © 2014 American Heart Association, Inc.

  9. The implications of tolerance system interpretation on past and present dimensional variability studies

    Energy Technology Data Exchange (ETDEWEB)

    Vaupel, W.G.; DeMeter, E.C.; Peters, F.E.; Voigt, R.C.

    1994-12-31

    Dimensional variability studies and published dimensional variability standards have been used by the foundry industry for years as an indicator of the casting process` ability to produce uniform parts. These studies are an extremely useful tool in the continuous ``dimensional dialogue`` between foundries and customers. The nature of these studies, and of the current tolerancing systems used by casting designers, leaves room for some misinterpretation and misuse of these study results. This paper contains two important discussions. The first part explains exactly what these studies represent. Following this is a brief explanation on dimensional and geometric tolerances and how they communicate dimensional requirements.

  10. Estimates of genetic variability and association studies in quantitative plant traits of Eruca spp. landraces

    Directory of Open Access Journals (Sweden)

    Bozokalfa Kadri Mehmet

    2010-01-01

    Full Text Available Despite the increasing of economical importance of rocket plant limited information is available on genetic variability for the agronomic traits among Eruca spp. Hence, heritability and association studies of plant properties are necessities for a successful further rocket breeding programme. The objective of this study was to examine phenotypic and genotypic variability, broad sense heritability, genetic advance, genotypic and phenotypic correlation and mean for agronomic traits of rocket plant. The magnitude of phenotypic coefficient of variation values for all the traits were higher than the corresponding values and broad sense heritability estimates exceeded 65% for all traits. Phenotypic coefficients of variability (PCV ranged from 7.60 to 34.34% and genotypic coefficients of variability (GCV ranged between 5.58% for petiole thickness and 34.30% for plant weight. The results stated that plant weight, siliqua width, seed per siliqua and seed weight could be useful character for improved Eruca spp. breeding programme.

  11. Improving preparedness of farmers to Climate Variability: A case study of Vidarbha region of Maharashtra, India

    Science.gov (United States)

    Swami, D.; Parthasarathy, D.; Dave, P.

    2016-12-01

    A key objective of the ongoing research is to understand the risk and vulnerability of agriculture and farming communities with respect to multiple climate change attributes, particularly monsoon variability and hydrology such as ground water availability. Climate Variability has always been a feature affecting Indian agriculture but the nature and characteristics of this variability is not well understood. Indian monsoon patterns are highly variable and most of the studies focus on larger domain such as Central India or Western coast (Ghosh et al., 2009) but district level analysis is missing i.e. the linkage between agriculture and climate variables at finer scale has not been investigated comprehensively. For example, Eastern Vidarbha region in Maharashtra is considered as one of the most agriculturally sensitive region in India, where every year a large number of farmers commit suicide. The main reasons for large number of suicides are climate related stressors such as droughts, hail storms, and monsoon variability aggravated with poor socio-economic conditions. Present study has tried to explore the areas in Vidarbha region of Maharashtra where famers and crop productivity, specifically cotton, sorghum, is highly vulnerable to monsoon variability, hydrological and socio-economic variables which are further modelled to determine the maximal contributing factor towards crops and farmers' vulnerability. After analysis using primary and secondary data, it will aid in decision making regarding field operations such as time of sowing, harvesting and irrigation requirements by optimizing the cropping pattern with climatic, hydrological and socio-economic variables. It also suggests the adaptation strategies to farmers regarding different types of cropping and water harvesting practices, optimized dates and timings for harvesting, sowing, water and nutrient requirements of particular crops according to the specific region. Primarily along with secondary analysis

  12. Studies of an x ray selected sample of cataclysmic variables. Ph.D. Thesis

    Science.gov (United States)

    Silber, Andrew D.

    1986-01-01

    Just prior to the thesis research, an all-sky survey in hard x rays with the HEAO-1 satellite and further observations in the optical resulted in a catalog of about 700 x-ray sources with known optical counterparts. This sample includes 43 cataclysmic variables, which are binaries consisting of a detached white-dwarf and a Roche lobe filling companion star. This thesis consists of studies of the x-ray selected sample of catalcysmic variables.

  13. Variable selection for multiply-imputed data with application to dioxin exposure study.

    Science.gov (United States)

    Chen, Qixuan; Wang, Sijian

    2013-09-20

    Multiple imputation (MI) is a commonly used technique for handling missing data in large-scale medical and public health studies. However, variable selection on multiply-imputed data remains an important and longstanding statistical problem. If a variable selection method is applied to each imputed dataset separately, it may select different variables for different imputed datasets, which makes it difficult to interpret the final model or draw scientific conclusions. In this paper, we propose a novel multiple imputation-least absolute shrinkage and selection operator (MI-LASSO) variable selection method as an extension of the least absolute shrinkage and selection operator (LASSO) method to multiply-imputed data. The MI-LASSO method treats the estimated regression coefficients of the same variable across all imputed datasets as a group and applies the group LASSO penalty to yield a consistent variable selection across multiple-imputed datasets. We use a simulation study to demonstrate the advantage of the MI-LASSO method compared with the alternatives. We also apply the MI-LASSO method to the University of Michigan Dioxin Exposure Study to identify important circumstances and exposure factors that are associated with human serum dioxin concentration in Midland, Michigan.

  14. The contribution of interindividual factors to variability of response in transcranial direct current stimulation studies

    Directory of Open Access Journals (Sweden)

    Lucia M Li

    2015-05-01

    Full Text Available There has been an explosion of research using transcranial direct current stimulation (tDCS for investigating and modulating human cognitive and motor function in healthy populations. It has also been used in many studies seeking to improve deficits in disease populations. With the slew of studies reporting ‘promising results’ for everything from motor recovery after stroke to boosting memory function, one could be easily seduced by the idea of tDCS being the next panacea for all neurological ills. However, huge variability exists in the reported effects of tDCS, with great variability in the effect sizes and even contradictory results reported. In this review, we consider the interindividual factors that may contribute to this variability. In particular, we discuss the importance of baseline neuronal state and features, anatomy, age and the inherent variability in the injured brain. We additionally consider how interindividual variability affects the results of motor evoked potential (MEP testing with transcranial magnetic stimulation (TMS, which, in turn, can lead to apparent variability in response to tDCS in motor studies.

  15. Investigating Lifelong Learning Dispositions of Students Studying English Language and Literature in Terms of Different Variables

    Science.gov (United States)

    Elaldi, Senel

    2015-01-01

    This study aims to determine lifelong learning dispositions of English Language and Literature students in terms of gender, grade levels, and age variables. Descriptive research design was used. The study group consisted of 402 students studying English Language and Literature at Cumhuriyet University in Sivas, Turkey. Research data were collected…

  16. A study of the photometric variability of the peculiar magnetic white dwarf WD1953-011

    CERN Document Server

    Valyavin, G; Plachinda, S; Clark, D M; Wade, G A; Machado, L Fox; Alvarez, M; Lopez, J M; Hiriart, D; Han, Inwoo; Jeon, Young-Beom; Bagnulo, S; Zharikov, S V; Zurita, C; Mujica, R; Shulyak, D; Burlakova, T

    2011-01-01

    We present and interpret simultaneous new photometric and spectroscopic observations of the peculiar magnetic white dwarf WD1953-011. The flux in the V-band filter and intensity of the Balmer spectral lines demonstrate variability with the rotation period of about 1.45 days. According to previous studies, this variability can be explained by the presence of a dark spot having a magnetic nature, analogous to a sunspot. Motivated by this idea, we examine possible physical relationships between the suggested dark spot and the strong-field magnetic structure (magnetic "spot", or "tube") recently identified on the surface of this star. Comparing the rotationally-modulated flux with the variable spectral observables related to the magnetic "spot" we establish their correlation, and therefore their physical relationship. Modeling the variable photometric flux assuming that it is associated with temperature variations in the stellar photosphere, we argue that the strong-field area and dark, low-temperature spot are c...

  17. Statistically Non-significant Papers in Environmental Health Studies included more Outcome Variables

    Institute of Scientific and Technical Information of China (English)

    Pentti Nieminen; Khaled Abass; Kirsi Vhkanga; Arja Rautio

    2015-01-01

    Objective The number of analyzed outcome variables is important in the statistical analysis and interpretation of research findings. This study investigated published papers in the field of environmental health studies. We aimed to examine whether differences in the number of reported outcome variables exist between papers with non-significant findings compared to those with significant findings. Articles on the maternal exposure to mercury and child development were used as examples. Methods Articles published between 1995 and 2013 focusing on the relationships between maternal exposure to mercury and child development were collected from Medline and Scopus. Results Of 87 extracted papers, 73 used statistical significance testing and 38 (43.7%) of these reported ‘non-significant’ (P>0.05) findings. The median number of child development outcome variables in papers reporting ‘significant’ (n=35) and ‘non-significant’ (n=38) results was 4 versus 7, respectively (Mann-Whitney test P-value=0.014). An elevated number of outcome variables was especially found in papers reporting non-significant associations between maternal mercury and outcomes when mercury was the only analyzed exposure variable. Conclusion Authors often report analyzed health outcome variables based on their P-values rather than on stated primary research questions. Such a practice probably skews the research evidence.

  18. Phylogenetic evidence for a fusion of archaeal and bacterial SemiSWEETs to form eukaryotic SWEETs and identification of SWEET hexose transporters in the amphibian chytrid pathogen Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Hu, Yi-Bing; Sosso, Davide; Qu, Xiao-Qing; Chen, Li-Qing; Ma, Lai; Chermak, Diane; Zhang, De-Chun; Frommer, Wolf B

    2016-10-01

    SWEETs represent a new class of sugar transporters first described in plants, animals, and humans and later in prokaryotes. Plant SWEETs play key roles in phloem loading, seed filling, and nectar secretion, whereas the role of archaeal, bacterial, and animal transporters remains elusive. Structural analyses show that eukaryotic SWEETs are composed of 2 triple-helix bundles (THBs) fused via an inversion linker helix, whereas prokaryotic SemiSWEETs contain only a single THB and require homodimerization to form transport pores. This study indicates that SWEETs retained sugar transport activity in all kingdoms of life, and that SemiSWEETs are likely their ancestral units. Fusion of oligomeric subunits into single polypeptides during evolution of eukaryotes is commonly found for transporters. Phylogenetic analyses indicate that THBs of eukaryotic SWEETs may not have evolved by tandem duplication of an open reading frame, but rather originated by fusion between an archaeal and a bacterial SemiSWEET, which potentially explains the asymmetry of eukaryotic SWEETs. Moreover, despite the ancient ancestry, SWEETs had not been identified in fungi or oomycetes. Here, we report the identification of SWEETs in oomycetes as well as SWEETs and a potential SemiSWEET in primitive fungi. BdSWEET1 and BdSWEET2 from Batrachochytrium dendrobatidis, a nonhyphal zoosporic fungus that causes global decline in amphibians, showed glucose and fructose transport activities.-Hu, Y.-B., Sosso, D., Qu, X.-Q., Chen, L.-Q., Ma, L., Chermak, D., Zhang, D.-C., Frommer, W. B. Phylogenetic evidence for a fusion of archaeal and bacterial SemiSWEETs to form eukaryotic SWEETs and identification of SWEET hexose transporters in the amphibian chytrid pathogen Batrachochytrium dendrobatidis. © FASEB.

  19. A Statewide Study of Academic Variables Affecting Performance of Baccalaureate Nursing Graduates on Licensure Examination.

    Science.gov (United States)

    McClelland, Eleanor; And Others

    1992-01-01

    A study validated findings from two previous studies investigating the relationships between admission selection variables and achievement in baccalaureate nursing programs and performance on the National Council Licensure Examination for Registered Nurses (NCLEX-RN). Results suggest that students' prenursing grade point average and American…

  20. Using Statistical Process Control Charts to Study Stuttering Frequency Variability during a Single Day

    Science.gov (United States)

    Karimi, Hamid; O'Brian, Sue; Onslow, Mark; Jones, Mark; Menzies, Ross; Packman, Ann

    2013-01-01

    Purpose: Stuttering varies between and within speaking situations. In this study, the authors used statistical process control charts with 10 case studies to investigate variability of stuttering frequency. Method: Participants were 10 adults who stutter. The authors counted the percentage of syllables stuttered (%SS) for segments of their speech…

  1. Using Statistical Process Control Charts to Study Stuttering Frequency Variability during a Single Day

    Science.gov (United States)

    Karimi, Hamid; O'Brian, Sue; Onslow, Mark; Jones, Mark; Menzies, Ross; Packman, Ann

    2013-01-01

    Purpose: Stuttering varies between and within speaking situations. In this study, the authors used statistical process control charts with 10 case studies to investigate variability of stuttering frequency. Method: Participants were 10 adults who stutter. The authors counted the percentage of syllables stuttered (%SS) for segments of their speech…

  2. Differences in kinetic variables between injured and noninjured novice runners : A prospective cohort study

    NARCIS (Netherlands)

    Bredeweg, Steef W.; Kluitenberg, Bas; Bessem, Bram; Buist, Ida

    2013-01-01

    Objectives: This prospective study examined differences in kinetic variables between injured and noninjured novice female and male runners and their potential contribution to RRIs. Design: A prospective cohort study. Methods: At baseline vertical ground reaction forces were assessed with an instrume

  3. Investigation of Social Studies Teachers' Intended Uses of Social Networks in Terms of Various Variables

    Science.gov (United States)

    Akgün, Ismail Hakan

    2016-01-01

    The aim of this research is to determine Social Studies teacher candidates' intended uses of social networks in terms of various variables. The research was carried out by using screening model of quantitative research methods. In the study, "The Social Network Intended Use Scale" was used as a data collection tool. As a result of the…

  4. A study on effects of demographic variables on success of social media

    Directory of Open Access Journals (Sweden)

    Marjan Mohammadreza

    2012-10-01

    Full Text Available In the recent years, social media have developed significantly and their usages have become main activities of internet users. The proposed study of this paper considers the effects of personal characteristics such as age, gender and marital status on social media. The study designs a questionnaire and distributes 385 questionnaires among students who are enrolled in different educational levels in governmental university named Allameh Tabatabayi university located in Tehran, Iran during the year of 2011. Because of abnormality of data, non-parametric test were used. In this research, we studied the effects of demographic variables on success of social media. The results showed that success of social media is more important among female students. Marriage situation shows that social media success variable is more important among married than single ones and, finally, this variable is more important among older people.

  5. Study of formulation variables on properties of glipizide mucoadhesive microspheres by factorial design

    Directory of Open Access Journals (Sweden)

    Hosmani A.H

    2009-12-01

    Full Text Available "nBackground and the Purpose of the study:The purpose of the study was formulate and systemsystematic evaluation in-vitro and in-vivo behaviour of Glipizide mucoadhesive microspheres using 32 full factorial design. "nMethods:Concentration of Polycarbophil and Sodium Alginate were selected as independent variables and the effects were checked on dependent variables like swelling index, mucoadhesion, drug entrapment efficiency and T75. In vivo studies were also performed to determine hypoglycemic activity of the mucoadhesive microspheres. "nResults:The best batch exhibited drug entrapment efficiency of 75%, swelling index of 1.8 and mucoadhesion was 100%. The drug release from the microspheres was also sustained for more than 9 hrs. Conclusion:The concentration of polycarbophil and sodium alginate had highly significant effects on dependent variables. In-vivo testing demonstrated a significant hypoglycemic effect of glipizide.

  6. Variables affecting learning in a simulation experience: a mixed methods study.

    Science.gov (United States)

    Beischel, Kelly P

    2013-02-01

    The primary purpose of this study was to test a hypothesized model describing the direct effects of learning variables on anxiety and cognitive learning outcomes in a high-fidelity simulation (HFS) experience. The secondary purpose was to explain and explore student perceptions concerning the qualities and context of HFS affecting anxiety and learning. This study used a mixed methods quantitative-dominant explanatory design with concurrent qualitative data collection to examine variables affecting learning in undergraduate, beginning nursing students (N = 124). Being ready to learn, having a strong auditory-verbal learning style, and being prepared for simulation directly affected anxiety, whereas learning outcomes were directly affected by having strong auditory-verbal and hands-on learning styles. Anxiety did not quantitatively mediate cognitive learning outcomes as theorized, although students qualitatively reported debilitating levels of anxiety. This study advances nursing education science by providing evidence concerning variables affecting learning outcomes in HFS.

  7. Revisiting Caroline Furness's An Introduction to the Study of Variable Stars on its Centenary (Poster abstract)

    Science.gov (United States)

    Larsen, K.

    2016-06-01

    (Abstract only) A century and one month ago (October 1915) Dr. Caroline Ellen Furness (1869-1936), Director of the Vassar College Observatory, published An Introduction to the Study of Variable Stars. Issued in honor of the fiftieth anniversary of the founding of Vassar College, the work was meant to fill a void in the literature, namely as both an introduction to the topic of variable stars and as a manual explaining how they should be observed and the resulting data analyzed. It was judged to be one of the hundred best books written by an American woman in the last hundred years at the 1933 World's Fair in Chicago. The book covers the relevant history of and background on types of variable stars, star charts, catalogs, and the magnitude scale, then describes observing techniques, including visual, photographic, and photoelectric photometry. The work finishes with a discussion of light curves and patterns of variability, with a special emphasis on eclipsing binaries and long period variables. Furness's work is a valuable snapshot of the state of astronomical knowledge, technology, and observing techniques from a century ago. This presentation will analyze both Furness's book and its reception in the scientific community, and draw parallels to current advice given to beginning variable star observers.

  8. A Comparative Study of Reduced Variables Based Flash and Conventional Flash

    DEFF Research Database (Denmark)

    Michelsen, Michael Locht; Yan, Wei; Stenby, Erling Halfdan

    Speeding up flash calculation is a central issue in compositional reservoir simulations since phase equilibrium calculation is the most time-consuming part in those simulations. The reduced variables methods, or the reduction methods, reformulate the original phase equilibrium problem with a smal......Speeding up flash calculation is a central issue in compositional reservoir simulations since phase equilibrium calculation is the most time-consuming part in those simulations. The reduced variables methods, or the reduction methods, reformulate the original phase equilibrium problem....... Most of the studies in the last decade suggest that the reduced variables methods are much more efficient than the conventional flash method. However, Haugen and Beckner questioned the advantages of the reduced variables methods in their recent paper (SPE 141399). A fair comparison between the reduced...... variables based flash and the conventional flash is not straightforward since the former is difficult to be formulated as unconstrained minimization and involves more complicated composition derivatives. With the recent formulations by Nichita and Graciaa (2010), it is possible to code the reduced variables...

  9. An overview of techniques for dealing with large numbers of independent variables in epidemiologic studies.

    Science.gov (United States)

    Dohoo, I R; Ducrot, C; Fourichon, C; Donald, A; Hurnik, D

    1997-01-01

    Many studies of health and production problems in livestock involve the simultaneous evaluation of large numbers of risk factors. These analyses may be complicated by a number of problems including: multicollinearity (which arises because many of the risk factors may be related (correlated) to each other), confounding, interaction, problems related to sample size (and hence the power of the study), and the fact that many associations are evaluated from a single dataset. This paper focuses primarily on the problem of multicollinearity and discusses a number of techniques for dealing with this problem. However, some of the techniques discussed may also help to deal with the other problems identified above. The first general approach to dealing with multicollinearity involves reducing the number of independent variables prior to investigating associations with the disease. Techniques to accomplish this include: (1) excluding variables after screening for associations among independent variables; (2) creating indices or scores which combine data from multiple factors into a single variable; (3) creating a smaller set of independent variables through the use of multivariable techniques such as principal components analysis or factor analysis. The second general approach is to use appropriate steps and statistical techniques to investigate associations between the independent variables and the dependent variable. A preliminary screening of these associations may be performed using simple statistical tests. Subsequently, multivariable techniques such as linear or logistic regression or correspondence analysis can be used to identify important associations. The strengths and limitations of these techniques are discussed and the techniques are demonstrated using a dataset from a recent study of risk factors for pneumonia in swine. Emphasis is placed on comparing correspondence analysis with other techniques as it has been used less in the epidemiology literature.

  10. Multi-wavelength Study of Blazars Using Variability as a Tool

    Science.gov (United States)

    Baliyan, Kiran S.; Kaur, Navpreet; Chandra, Sunil; Sameer, Sameer; Ganesh, Shashikiran

    2016-09-01

    Active galactic nuclei (AGN) are too compact to be resolved by any existing optical telescope facility, making it difficult to understand their structure and the emission processes responsible for their huge energy output. However, variability, one of their characteristic properties, provides a tool to probe the inner regions of AGN. Blazars are the best candidates for such a study, and hence a considerable amount of effort is being made to investigate variability in these sources across the electromagnetic spectrum. Here, using the Mt. Abu infrared observatory (MIRO) blazar monitoring program, we present intra-night, inter-night, and long term aspects of the variability in S5 0716+71, 3C66A, and OJ 287. These stars show significant variability on short (a few tens of mins, to a few hours, to a few days) to long term (months to years) timescales. Based on the light travel time argument, the shortest variability timescales (micro-variability) provide upper limits to the size of the emission region. While S5 0716 shows a very high duty cycle of variability (> 80 %), 3C66A shows a much lower intra day variability (IDV) duty cycle (< 20 %). All three show rapid variations within 2.5 to 3.5 hr, which, perhaps, are generated near the vicinity of black holes. Assuming this, estimates of the masses of the black holes are made at 10^{9} , 8×10^{8}, and 2.7×10^{9} M⨀ for S5 0716+71, 3C66A, and OJ 287, respectively. Multi-wavelength light-curves for the blazar PKS 1510-089 are discussed to infer the emission processes responsible for the recent flaring episodes in this source.

  11. [Mother-newborn relational risk - Study of prevalence and associated variables].

    Science.gov (United States)

    Muñoz, Maribel; Poo, Ana María; Baeza, Bernardita; Bustos, M Luis

    2015-01-01

    Clinical evidence reveals the importance of mother-newborn bonding experience for health promoting and maintenance of human life. If the newborn lacks care and affection, she/he may develop an attachment disorder. A predictive scale regarding the risk of mothernewborn relationships is available, which makes possible an early intervention to prevent the development of relational disorders. The aim of this study is to apply the Kimelman measurement scale to determine the relational risk in mother-newborn pairs, as well as the prevalence and the associated biopsychosocial variables. A cross-sectional study with a probabilistic sample of 333 mother-infant pairs in postpartum maternity at Temuco hospital. The Kimelman mother-newborn attachment assessment guide was used. Biopsychosocial variables were obtained from the mothers studied. The association of biopsychosocial variables with relational risk was analyzed using OR and confidence intervals of 95%. The prevalence of high relational risk was 43.8%. The associated biopsychosocial variables included, women with no steady partner, single parent, teenage mothers, unwanted and unplanned pregnancy. Almost half of the mothers were in the high risk group. Early identification of relational risk and its related variables could help in the intervention in this vulnerable group. Copyright © 2015. Publicado por Elsevier España, S.L.U.

  12. Near-infrared variability study of the central 2.3 arcmin × 2.3 arcmin of the Galactic Centre - I. Catalogue of variable sources

    Science.gov (United States)

    Dong, Hui; Schödel, Rainer; Williams, Benjamin F.; Nogueras-Lara, Francisco; Gallego-Cano, Eulalia; Gallego-Calvente, Teresa; Wang, Q. Daniel; Morris, Mark R.; Do, Tuan; Ghez, Andrea

    2017-09-01

    We used 4-yr baseline Hubble Space Telescope/Wide Field Camera 3 IR observations of the Galactic Centre in the F153M band (1.53 μm) to identify variable stars in the central ∼2.3 arcmin × 2.3 arcmin field. We classified 3845 long-term (periods from months to years) and 76 short-term (periods of a few days or less) variables among a total sample of 33 070 stars. For 36 of the latter ones, we also derived their periods (<3 d). Our catalogue not only confirms bright long period variables and massive eclipsing binaries identified in previous works but also contains many newly recognized dim variable stars. For example, we found δ Scuti and RR Lyrae stars towards the Galactic Centre for the first time, as well as one BL Her star (period < 1.3 d). We cross-correlated our catalogue with previous spectroscopic studies and found that 319 variables have well-defined stellar types, such as Wolf-Rayet, OB main sequence, supergiants and asymptotic giant branch stars. We used colours and magnitudes to infer the probable variable types for those stars without accurately measured periods or spectroscopic information. We conclude that the majority of unclassified variables could potentially be eclipsing/ellipsoidal binaries and Type II Cepheids. Our source catalogue will be valuable for future studies aimed at constraining the distance, star formation history and massive binary fraction of the Milky Way nuclear star cluster.

  13. The experimental studies of operating modes of a diesel-generator set at variable speed

    Science.gov (United States)

    Obukhov, S. G.; Plotnikov, I. A.; Surkov, M. A.; Sumarokova, L. P.

    2017-02-01

    A diesel generator set working at variable speed to save fuel is studied. The results of experimental studies of the operating modes of an autonomous diesel generator set are presented. Areas for regulating operating modes are determined. It is demonstrated that the transfer of the diesel generator set to variable speed of the diesel engine makes it possible to improve the energy efficiency of the autonomous generator source, as well as the environmental and ergonomic performance of the equipment as compared with general industrial analogues.

  14. Short term Heart Rate Variability to predict blood pressure drops due to standing: a pilot study.

    Science.gov (United States)

    Sannino, G; Melillo, P; Stranges, S; De Pietro, G; Pecchia, L

    2015-01-01

    Standing from a bed or chair may cause a significant lowering of blood pressure (ΔBP), which may have severe consequences such as, for example, falls in older subjects. The goal of this study was to develop a mathematical model to predict the ΔBP due to standing in healthy subjects, based on their Heart Rate Variability, recorded in the 5 minutes before standing. Heart Rate Variability was extracted from an electrocardiogram, recorded from 10 healthy subjects during the 5 minutes before standing. The blood pressure value was measured before and after rising. A mathematical model aiming to predict ΔBP based on Heart Rate Variability measurements was developed using a robust multi-linear regression and was validated with the leave-one-subject-out cross-validation technique. The model predicted correctly the ΔBP in 80% of experiments, with an error below the measurement error of sphygmomanometer digital devices (± 4.5 mmHg), a false negative rate of 7.5% and a false positive rate of 10%. The magnitude of the ΔBP was associated with a depressed and less chaotic Heart Rate Variability pattern. The present study showes that blood pressure lowering due to standing can be predicted by monitoring the Heart Rate Variability in the 5 minutes before standing.

  15. [Host-parasite metabolic relationship between puccinia graminis var. tritici and triticum vulgare (Wheat) : II. Uptake of hexoses from the host].

    Science.gov (United States)

    Pfeiffer, E; Jäger, K; Reisener, H J

    1969-06-01

    Rust infected leaves of wheat plants were incubated with glucose-(14)C. Uredospores which were formed during the application of the tracer were analyzed. All isolated compounds were labeled with (14)C. When germinating uredospores were incubated directly with (14)C-glucose, the isolated glutamic acid, arginine and lysine had practically no radioactivity. These compounds did, however, contain considerable (14)C-activity when they were isolated from uredospores formed on leaves that had been treated with the tracer. We therefore conclude that these amino acids were synthesized in the host and were taken up by the haustoria of the mycelium.High (14)C-radioactivity was also found in all carbohydrates (chitin, glucomannan, polyols etc.). Hexoses isolated from the spore constituents chitin and glucomannan showed the same distribution of radioactivity as the applied glucose-1-(14)C or glucose-6-(14)C. It follows that the rust mycelium takes up glucose or a similar monosaccharide from the wheat plant. The C-6-skeleton is not degraded to smaller metabolites before it is taken up.

  16. Growth and ethanol fermentation ability on hexose and pentose sugars and glucose effect under various conditions in thermotolerant yeast Kluyveromyces marxianus

    Energy Technology Data Exchange (ETDEWEB)

    Rodrussamee, Nadchanok; Hirata, Katsushi; Suprayogi [Yamaguchi Univ., Ube (Japan). Graduate School of Medicine; Lertwattanasakul, Noppon; Kosaka, Tomoyuki [Yamaguchi Univ. (Japan). Faculty of Agriculture; Limtong, Savitree [Kasetsart Univ., Bangkok (Thailand). Faculty of Science; Yamada, Mamoru [Yamaguchi Univ., Ube (Japan). Graduate School of Medicine; Yamaguchi Univ. (Japan). Faculty of Agriculture

    2011-05-15

    Ethanol fermentation ability of the thermotolerant yeast Kluyveromyces marxianus, which is able to utilize various sugars including glucose, mannose, galactose, xylose, and arabinose, was examined under shaking and static conditions at high temperatures. The yeast was found to produce ethanol from all of these sugars except for arabinose under a shaking condition but only from hexose sugars under a static condition. Growth and sugar utilization rate under a static condition were slower than those under a shaking condition, but maximum ethanol yield was slightly higher. Even at 40 C, a level of ethanol production similar to that at 30 C was observed except for galactose under a static condition. Glucose repression on utilization of other sugars was observed, and it was more evident at elevated temperatures. Consistent results were obtained by the addition of 2-deoxyglucose. The glucose effect was further examined at a transcription level, and it was found that KmGAL1 for galactokinase and KmXYL1 for xylose reductase for galactose and xylose/arabinose utilization, respectively, were repressed by glucose at low and high temperatures, but KmHXK2 for hexokinase was not repressed. We discuss the possible mechanism of glucose repression and the potential for utilization of K. marxianus in high-temperature fermentation with mixed sugars containing glucose. (orig.)

  17. Estimation of Finite Population Ratio When Other Auxiliary Variables are Available in the Study

    Directory of Open Access Journals (Sweden)

    Jehad Al-Jararha

    2014-12-01

    Full Text Available The estimation of the population total $t_y,$ by using one or moreauxiliary variables, and the population ratio $\\theta_{xy}=t_y/t_x,$$t_x$ is the population total for the auxiliary variable $X$, for afinite population are heavily discussed in the literature. In thispaper, the idea of estimation the finite population ratio$\\theta_{xy}$ is extended to use the availability of auxiliaryvariable $Z$ in the study, such auxiliary variable  is not used inthe definition of the population ratio. This idea may be  supported by the fact that the variable $Z$  is highly correlated with the interest variable $Y$ than the correlation between the variables $X$ and $Y.$ The availability of such auxiliary variable can be used to improve the precision of the estimation of the population ratio.  To our knowledge, this idea is not discussed in the literature.  The bias, variance and the mean squares error  are given for our approach. Simulation from real data set,  the empirical relative bias and  the empirical relative mean squares error are computed for our approach and different estimators proposed in the literature  for estimating the population ratio $\\theta_{xy}.$ Analytically and the simulation results show that, by suitable choices, our approach gives negligible bias and has less mean squares error.  

  18. Heterogeneity of Prognostic Studies of 24-Hour Blood Pressure Variability: Systematic Review and Meta-Analysis

    Science.gov (United States)

    Taylor, Kathryn S.; Heneghan, Carl J.; Stevens, Richard J.; Adams, Emily C.; Nunan, David; Ward, Alison

    2015-01-01

    In addition to mean blood pressure, blood pressure variability is hypothesized to have important prognostic value in evaluating cardiovascular risk. We aimed to assess the prognostic value of blood pressure variability within 24 hours. Using MEDLINE, EMBASE and Cochrane Library to April 2013, we conducted a systematic review of prospective studies of adults, with at least one year follow-up and any day, night or 24-hour blood pressure variability measure as a predictor of one or more of the following outcomes: all-cause mortality, cardiovascular mortality, all cardiovascular events, stroke and coronary heart disease. We examined how blood pressure variability is defined and how its prognostic use is reported. We analysed relative risks adjusted for covariates including the appropriate mean blood pressure and considered the potential for meta-analysis. Our analysis of methods included 24 studies and analysis of predictions included 16 studies. There were 36 different measures of blood pressure variability and 13 definitions of night- and day-time periods. Median follow-up was 5.5 years (interquartile range 4.2–7.0). Comparing measures of dispersion, coefficient of variation was less well researched than standard deviation. Night dipping based on percentage change was the most researched measure and the only measure for which data could be meaningfully pooled. Night dipping or lower night-time blood pressure was associated with lower risk of cardiovascular events. The interpretation and use in clinical practice of 24-hour blood pressure variability, as an important prognostic indicator of cardiovascular events, is hampered by insufficient evidence and divergent methodologies. We recommend greater standardisation of methods. PMID:25984791

  19. Heterogeneity of prognostic studies of 24-hour blood pressure variability: systematic review and meta-analysis.

    Science.gov (United States)

    Taylor, Kathryn S; Heneghan, Carl J; Stevens, Richard J; Adams, Emily C; Nunan, David; Ward, Alison

    2015-01-01

    In addition to mean blood pressure, blood pressure variability is hypothesized to have important prognostic value in evaluating cardiovascular risk. We aimed to assess the prognostic value of blood pressure variability within 24 hours. Using MEDLINE, EMBASE and Cochrane Library to April 2013, we conducted a systematic review of prospective studies of adults, with at least one year follow-up and any day, night or 24-hour blood pressure variability measure as a predictor of one or more of the following outcomes: all-cause mortality, cardiovascular mortality, all cardiovascular events, stroke and coronary heart disease. We examined how blood pressure variability is defined and how its prognostic use is reported. We analysed relative risks adjusted for covariates including the appropriate mean blood pressure and considered the potential for meta-analysis. Our analysis of methods included 24 studies and analysis of predictions included 16 studies. There were 36 different measures of blood pressure variability and 13 definitions of night- and day-time periods. Median follow-up was 5.5 years (interquartile range 4.2-7.0). Comparing measures of dispersion, coefficient of variation was less well researched than standard deviation. Night dipping based on percentage change was the most researched measure and the only measure for which data could be meaningfully pooled. Night dipping or lower night-time blood pressure was associated with lower risk of cardiovascular events. The interpretation and use in clinical practice of 24-hour blood pressure variability, as an important prognostic indicator of cardiovascular events, is hampered by insufficient evidence and divergent methodologies. We recommend greater standardisation of methods.

  20. Heterogeneity of prognostic studies of 24-hour blood pressure variability: systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Kathryn S Taylor

    Full Text Available In addition to mean blood pressure, blood pressure variability is hypothesized to have important prognostic value in evaluating cardiovascular risk. We aimed to assess the prognostic value of blood pressure variability within 24 hours. Using MEDLINE, EMBASE and Cochrane Library to April 2013, we conducted a systematic review of prospective studies of adults, with at least one year follow-up and any day, night or 24-hour blood pressure variability measure as a predictor of one or more of the following outcomes: all-cause mortality, cardiovascular mortality, all cardiovascular events, stroke and coronary heart disease. We examined how blood pressure variability is defined and how its prognostic use is reported. We analysed relative risks adjusted for covariates including the appropriate mean blood pressure and considered the potential for meta-analysis. Our analysis of methods included 24 studies and analysis of predictions included 16 studies. There were 36 different measures of blood pressure variability and 13 definitions of night- and day-time periods. Median follow-up was 5.5 years (interquartile range 4.2-7.0. Comparing measures of dispersion, coefficient of variation was less well researched than standard deviation. Night dipping based on percentage change was the most researched measure and the only measure for which data could be meaningfully pooled. Night dipping or lower night-time blood pressure was associated with lower risk of cardiovascular events. The interpretation and use in clinical practice of 24-hour blood pressure variability, as an important prognostic indicator of cardiovascular events, is hampered by insufficient evidence and divergent methodologies. We recommend greater standardisation of methods.

  1. A longitudinal study in youth of heart rate variability at rest and in response to stress

    NARCIS (Netherlands)

    Li, Zhibin; Snieder, Harold; Su, Shaoyong; Ding, Xiuhua; Thayer, Julian F.; Treiber, Frank A.; Wang, Xiaoling

    2009-01-01

    Background: Few longitudinal studies have examined ethnic and sex differences, predictors and tracking stabilities of heart rate variability (HRV) at rest and in response to stress in youths and young adults. Methods: Two evaluations were performed approximately 1.5 years apart on 399 youths and you

  2. The Relationship between Grades Earned in Introductory Nursing Courses and Several Predictor Variables: An Exploratory Study.

    Science.gov (United States)

    Spahr, Anthony E.

    A study was conducted at Morton College (Illinois) to gain a better understanding of the factors which contribute to academic success in introductory nursing courses, and to investigate the relationship between the following variables: student grades in Fundamentals of Nursing I and II, Anatomy and Physiology I, and Rhetoric I; and their scores on…

  3. Studying Differential Item Functioning via Latent Variable Modeling: A Note on a Multiple-Testing Procedure

    Science.gov (United States)

    Raykov, Tenko; Marcoulides, George A.; Lee, Chun-Lung; Chang, Chi

    2013-01-01

    This note is concerned with a latent variable modeling approach for the study of differential item functioning in a multigroup setting. A multiple-testing procedure that can be used to evaluate group differences in response probabilities on individual items is discussed. The method is readily employed when the aim is also to locate possible…

  4. Design study of a continuously variable roller cone traction CVT for electric vehicles

    Science.gov (United States)

    Mccoin, D. K.; Walker, R. D.

    1980-01-01

    Continuously variable ratio transmissions (CVT) featuring cone and roller traction elements and computerized controls are studied. The CVT meets or exceeds all requirements set forth in the design criteria. Further, a scalability analysis indicates the basic concept is applicable to lower and higher power units, with upward scaling for increased power being more readily accomplished.

  5. Influence of turbulence on power quality. Comparative study between constant and variable wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Longatt, Francisco M. [Universidad Nacional Experimental Politecnica de la Fuerza Armada Nacional (UNEFA), Aragua (Venezuela). Grupo de Investigaciones Avanzadas en Energia

    2008-07-01

    Turbulence is clearly a complex process, and one which cannot be represented simply in terms of deterministic equations. The main objective of this paper is a comparative study of impact on dynamic behavior on constant and variable speed wind turbines considering several turbulence sceneries. We consider integration on a test system of squirrel cage induction generator for constant speed wind turbine, and doubly fed induction generator for variable speed wind turbine. Several simulations with different intensity of turbulences were developed, and conclusions are presented. Good dynamic behavior is evident on doubly fed induction generator, with controls. (orig.)

  6. Study of the Lie symmetries of a relativistic variable mass system

    Institute of Scientific and Technical Information of China (English)

    方建会

    2002-01-01

    The differential equations of motion of a relativistic variable mass system are given. By using the invariance of the differential equations under the infinitesimal transformations of groups, the determining equations and the restriction equations of the Lie symmetries of a relativistic variable mass system are built, and the structure equation and the conserved quantity of the Lie symmetries are obtained. Then the inverse problem of the Lie symmetries is studied. The corresponding Lie symmetries are found according to a known conserved quantity. An example is given to illustrate the application of the result.

  7. Evaluation of the highly variable agomelatine pharmacokinetics in Chinese healthy subjects to support bioequivalence study.

    Directory of Open Access Journals (Sweden)

    Qi Pei

    Full Text Available OBJECTIVES: We aim to obtain the intra-subject coefficient of variability of a highly variable antidepressant agomelatine in humans, and propose an adjusted bioequivalence assessment strategy. METHODS: A single-dose, randomized crossover design was conducted in four periods (reference administered thrice, placebo administered once separated by seven days. A validated LC-MS/MS assay was used to measure drug concentrations in serial blood samples. RESULTS: The intra-subject coefficient of variability was calculated using the residual variance of ANOVA analysis, and the results for Cmax and AUC0-t was 78.34% and 43.52%, respectively, in Chinese healthy subjects. The sample size required for standard BE study were 124(192, 340 if the expected deviation between the reference and generic products was set to 0 (5%, 10%. CONCLUSIONS: Agomelatine meets the criteria for highly variable drug in Chinese healthy male subjects, and the traditional BE criteria for agomelatine needs to be adjusted to alleviate the resource and ethical burden of using a large numbers of subjects in clinical trials. Our clinical data on the intra-subject variability of agomelatine PK in Chinese healthy population enables to adjust bioequivalence (BE assessment approach for agomelatine based on the RSABE approaches recommended by regulatory agencies. TRIAL REGISTRATION: ChiCTR.org ChiCTR-TTRCC-13003835.

  8. A Study of the Effective Variables on Earning Management: Iranian Evidence

    Directory of Open Access Journals (Sweden)

    Mahdi Moradi

    2012-08-01

    Full Text Available The current study aims to examine the effective variables an earning management in Tehran Stock exchange during 2004 -2010. In this research the discretionary accruals from modified Jones model to determine earning management in the firms have been used and auditor change and type of auditor (for examining accounting quality, type of ownership, number of main shareholders, percentage of ownership for largest shareholder, percentage of ownership main shareholders (for examining corporate governance, incentives of earning management (number of employee, equity-debt ratio, leverage and tax and also financial ratios (performance coefficient, changes in net income, gross income to sale ratio and current ratio, used firm size and type of industry variables have been considered as control variable. To analyze data the multiple regression and backward regression as well as interaction regression have been used cross-sectionally and collectively.

  9. A Pilot Study to Identify Modifiable and Nonmodifiable Variables Associated With Osteopenia and Osteoporosis in Men.

    Science.gov (United States)

    Fasolino, Tracy; Whitright, Theresa

    2015-01-01

    Osteoporosis is typically associated with women, but men can also be affected. Less is known about the factors influencing the development of osteoporosis in the male population. This pilot study attempted to identify variables associated with osteopenia or osteoporosis in men. The 101 male participants completed a questionnaire that examined modifiable and nonmodifiable variables: alcohol consumption, smoking, exercise history, fracture history as an adult, and family history of osteoporosis. Objective variables collected included age, height, and weight to calculate body mass index. Bone mineral density was calculated using dual-energy x-ray absorptiometry. Osteopenia or osteoporosis was identified in 62 of the male participants. Consumption of alcohol and cigarettes with higher body mass index was correlated with greater likelihood of osteopenia and osteoporosis.

  10. Collective variables for the study of long-time kinetics from molecular trajectories: theory and methods.

    Science.gov (United States)

    Noé, Frank; Clementi, Cecilia

    2017-04-01

    Collective variables are an important concept to study high-dimensional dynamical systems, such as molecular dynamics of macromolecules, liquids, or polymers, in particular to define relevant metastable states and state-transition or phase-transition. Over the past decade, a rigorous mathematical theory has been formulated to define optimal collective variables to characterize slow dynamical processes. Here we review recent developments, including a variational principle to find optimal approximations to slow collective variables from simulation data, and algorithms such as the time-lagged independent component analysis. Using these concepts, a distance metric can be defined that quantifies how slowly molecular conformations interconvert. Extensions and open questions are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. STATIC AND DYNAMIC LOCATION OF VARIABLE IMPEDANCE DEVICES FOR STABILITY STUDIES

    Directory of Open Access Journals (Sweden)

    N. Magaji

    2013-01-01

    Full Text Available This study used the concept of model controllability and observability in product form called residue factor to find the best location of Thyristor-Controlled based series and shunt devices called variable impedance devices. The success of this controller depends on its best possible location in busbar or line of power system network. The method is based on the relationship between the parameters of variable impedance devices to the vital modes. Linearization of non linear model of Power system and the thyristors based FACTS devices provide mens of computing residue factor and singular value factor. The location of variable impedance or thyristors based controllers have been calculated for the base case only. The usefulness of the these methods of placement considered 16 machines, 68 bus systems.

  12. Study of variable stars in the MOA data base long-period red variables in the Large Magellanic Cloud

    CERN Document Server

    Noda, S; Abe, F; Bond, I A; Dodd, R J; Hearnshaw, J B; Honda, M; Honma, M; Juga Ku Jun; Kabe, S; Kan-Ya, Y; Kato, Y; Kilmartin, P M; Matsubara, Y; Masuda, K; Muraki, Y; Nakamura, T; Nankivell, G R; Noguchi, C; Ohnishi, K; Reid, M; Rattenbury, N J; Saitô, T; Sato, H; Sekiguchi, M; Skuljan, J; Sullivan, D J; Sumi, T; Watase, Y; Wilkinson, S; Yamada, R; Yanagisawa, T; Yock, P C M; Yoshizawa, M; Saito, To.

    2002-01-01

    One hundred and forty six long-period red variable stars in the Large Magellanic Cloud (LMC) from the three year MOA project database were analysed. A careful periodic analysis was performed on these stars and a catalogue of their magnitudes, colours, periods and amplitudes is presented. We convert our blue and red magnitudes to $K$ band values using 19 oxygen-rich stars. A group of red short-period stars separated from the Mira sequence has been found on a (log P, K) diagram. They are located at the short period side of the Mira sequence consistent with the work of Wood and Sebo (1996). There are two interpretations for such stars; a difference in pulsation mode or a difference in chemical composition. We investigated the properties of these stars together with their colour, amplitude and periodicity. We conclude that they have small amplitudes and less regular variability. They are likely to be higher mode pulsators. A large scatter has been also found on the long period side of the (log P, K) diagram. This...

  13. Heart rate variability and particulate exposure in vehicle maintenance workers: a pilot study.

    Science.gov (United States)

    Eninger, Robert M; Rosenthal, Frank S

    2004-08-01

    The association between occupational exposure to PM(2.5) and heart rate variability was investigated in a repeated measures, longitudinal study of vehicle maintenance workers occupationally exposed to automobile emissions. Five subjects were monitored for occupational exposure to fine particulate matter (PM(2.5)) on 6 workdays using an aerosol photometer, validated with side-by-side sampling with a gravimetric method. End-of-day heart rate variability statistics were derived using short-term electrocardiogram recordings for each participant. Workplace carbon monoxide and outdoor, ambient fine particulate matter were also monitored. Regression statistics were used to investigate associations between same-day PM(2.5) levels and heart rate variability statistics using mixed-effects multiple regression of pooled data. No statistically significant associations were observed between occupational PM(2.5) and measures of heart rate variability. A statistically significant increase in total spectral power was associated with ambient PM(2.5) (p < 0.05). The data suggest a threshold below which no degradation in cardiac autonomic control of healthy workers occurs when challenged by occupational PM(2.5) exposure. This study was limited in population, exposure level, and type of particulate exposures. Additional studies are recommended on broader occupational populations.

  14. Confounding, causality, and confusion: the role of intermediate variables in interpreting observational studies in obstetrics.

    Science.gov (United States)

    Ananth, Cande V; Schisterman, Enrique F

    2017-08-01

    Prospective and retrospective cohorts and case-control studies are some of the most important study designs in epidemiology because, under certain assumptions, they can mimic a randomized trial when done well. These assumptions include, but are not limited to, properly accounting for 2 important sources of bias: confounding and selection bias. While not adjusting the causal association for an intermediate variable will yield an unbiased estimate of the exposure-outcome's total causal effect, it is often that obstetricians will want to adjust for an intermediate variable to assess if the intermediate is the underlying driver of the association. Such a practice must be weighed in light of the underlying research question and whether such an adjustment is necessary should be carefully considered. Gestational age is, by far, the most commonly encountered variable in obstetrics that is often mislabeled as a confounder when, in fact, it may be an intermediate. If, indeed, gestational age is an intermediate but if mistakenly labeled as a confounding variable and consequently adjusted in an analysis, the conclusions can be unexpected. The implications of this overadjustment of an intermediate as though it were a confounder can render an otherwise persuasive study downright meaningless. This commentary provides an exposition of confounding bias, collider stratification, and selection biases, with applications in obstetrics and perinatal epidemiology. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Assessing the reporting of categorised quantitative variables in observational epidemiological studies.

    Science.gov (United States)

    Mabikwa, Onkabetse V; Greenwood, Darren C; Baxter, Paul D; Fleming, Sarah J

    2017-03-14

    One aspect to consider when reporting results of observational studies in epidemiology is how quantitative risk factors are analysed. The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines recommend that researchers describe how they handle quantitative variables when analysing data. For categorised quantitative variables, the authors are required to provide reasons and justifications informing their practice. We investigated and assessed the practices and reporting of categorised quantitative variables in epidemiology. The assessment was based on five medical journals that publish epidemiological research. Observational studies published between April and June 2015 and investigating the relationships between quantitative exposures (or risk factors) and the outcomes were considered for assessment. A standard form was used to collect the data, and the reporting patterns amongst eligible studies were quantified and described. Out of 61 articles assessed for eligibility, 23 observational studies were included in the assessment. Categorisation of quantitative exposures occurred in 61% of these studies and reasons informing the practice were rarely provided. Only one article explained the choice of categorisation in the analysis. Transformation of quantitative exposures into four or five groups was common and dominant amongst studies using equally spaced categories. Dichotomisation was not popular; the practice featured in one article. Overall, the majority (86%) of the studies preferred ordered or arbitrary group categories. Other criterions used to decide categorical boundaries were based on established guidelines such as consensus statements and WHO standards. Categorisation of continuous variables remains a dominant practice in epidemiological studies. The reasons informing the practice of categorisation within published work are limited and remain unknown in most articles. The existing STROBE guidelines could provide stronger

  16. Variability of indication criteria in knee and hip replacement: an observational study

    Directory of Open Access Journals (Sweden)

    Sarasqueta Cristina

    2010-10-01

    Full Text Available Abstract Background Total knee (TKR and hip (THR replacement (arthroplasty are effective surgical procedures that relieve pain, improve patients' quality of life and increase functional capacity. Studies on variations in medical practice usually place the indications for performing these procedures to be highly variable, because surgeons appear to follow different criteria when recommending surgery in patients with different severity levels. We therefore proposed a study to evaluate inter-hospital variability in arthroplasty indication. Methods The pre-surgical condition of 1603 patients included was compared by their personal characteristics, clinical situation and self-perceived health status. Patients were asked to complete two health-related quality of life questionnaires: the generic SF-12 (Short Form and the specific WOMAC (Western Ontario and Mcmaster Universities scale. The type of patient undergoing primary arthroplasty was similar in the 15 different hospitals evaluated. The variability in baseline WOMAC score between hospitals in THR and TKR indication was described by range, mean and standard deviation (SD, mean and standard deviation weighted by the number of procedures at each hospital, high/low ratio or extremal quotient (EQ5-95, variation coefficient (CV5-95 and weighted variation coefficient (WCV5-95 for 5-95 percentile range. The variability in subjective and objective signs was evaluated using median, range and WCV5-95. The appropriateness of the procedures performed was calculated using a specific threshold proposed by Quintana et al for assessing pain and functional capacity. Results The variability expressed as WCV5-95 was very low, between 0.05 and 0.11 for all three dimensions on WOMAC scale for both types of procedure in all participating hospitals. The variability in the physical and mental SF-12 components was very low for both types of procedure (0.08 and 0.07 for hip and 0.03 and 0.07 for knee surgery patients

  17. Study of Bias in 2012-Placement Test through Rasch Model in Terms of Gender Variable

    Science.gov (United States)

    Turkan, Azmi; Cetin, Bayram

    2017-01-01

    Validity and reliability are among the most crucial characteristics of a test. One of the steps to make sure that a test is valid and reliable is to examine the bias in test items. The purpose of this study was to examine the bias in 2012 Placement Test items in terms of gender variable using Rasch Model in Turkey. The sample of this study was…

  18. Regional Fat Distribution and Blood Pressure Level and Variability: The Dallas Heart Study.

    Science.gov (United States)

    Yano, Yuichiro; Vongpatanasin, Wanpen; Ayers, Colby; Turer, Aslan; Chandra, Alvin; Carnethon, Mercedes R; Greenland, Philip; de Lemos, James A; Neeland, Ian J

    2016-09-01

    Our aim was to investigate the associations of regional fat distribution with home and office blood pressure (BP) levels and variability. Participants in the Dallas Heart Study, a multiethnic cohort, underwent 5 BP measurements on 3 occasions during 5 months (2 in home and 1 in office) and quantification of visceral adipose tissue, abdominal subcutaneous adipose tissue, and liver fat by magnetic resonance imaging, and lower body subcutaneous fat by dual x-ray absorptiometry. The relation of regional adiposity with short-term (within-visit) and long-term (overall visits) mean BP and average real variability was assessed with multivariable linear regression. We have included 2595 participants with a mean age of 44 years (54% women; 48% black), and mean body mass index was 29 kg/m(2) Mean systolic BP/diastolic BP was 127/79 mm Hg and average real variability systolic BP was 9.8 mm Hg during 3 visits. In multivariable-adjusted models, higher amount of visceral adipose tissue was associated with higher short-term (both home and office) and long-term mean systolic BP (β[SE]: 1.9[0.5], 2.7[0.5], and 2.1[0.5], respectively; all Pfat was associated with lower short-term home and long-term mean BP (β[SE]: -0.30[0.13] and -0.24[0.1], respectively; both Pfat was associated with BP levels or variability. In conclusion, excess visceral fat was associated with persistently higher short- and long-term mean BP levels and with lower long-term BP variability, whereas lower body fat was associated with lower short- and long-term mean BP. Persistently elevated BP, coupled with lower variability, may partially explain increased risk for cardiac hypertrophy and failure related to visceral adiposity.

  19. Discriminative variable subsets in Bayesian classification with mixture models, with application in flow cytometry studies.

    Science.gov (United States)

    Lin, Lin; Chan, Cliburn; West, Mike

    2016-01-01

    We discuss the evaluation of subsets of variables for the discriminative evidence they provide in multivariate mixture modeling for classification. The novel development of Bayesian classification analysis presented is partly motivated by problems of design and selection of variables in biomolecular studies, particularly involving widely used assays of large-scale single-cell data generated using flow cytometry technology. For such studies and for mixture modeling generally, we define discriminative analysis that overlays fitted mixture models using a natural measure of concordance between mixture component densities, and define an effective and computationally feasible method for assessing and prioritizing subsets of variables according to their roles in discrimination of one or more mixture components. We relate the new discriminative information measures to Bayesian classification probabilities and error rates, and exemplify their use in Bayesian analysis of Dirichlet process mixture models fitted via Markov chain Monte Carlo methods as well as using a novel Bayesian expectation-maximization algorithm. We present a series of theoretical and simulated data examples to fix concepts and exhibit the utility of the approach, and compare with prior approaches. We demonstrate application in the context of automatic classification and discriminative variable selection in high-throughput systems biology using large flow cytometry datasets.

  20. Use of the IRAP marker to study genetic variability in Pseudocercospora fijiensis populations.

    Science.gov (United States)

    de Queiroz, Casley Borges; Santana, Mateus Ferreira; da Silva, Gilvan Ferreira; Mizubuti, Eduardo Seiti Gomide; de Araújo, Elza Fernandes; de Queiroz, Marisa Vieira

    2014-03-01

    Pseudocercospora fijiensis is the etiological agent of black Sigatoka, which is currently considered as one of the most destructive banana diseases in all locations where it occurs. It is estimated that a large portion of the P. fijiensis genome consists of transposable elements, which allows researchers to use transposon-based molecular markers in the analysis of genetic variability in populations of this pathogen. In this context, the inter-retrotransposon-amplified polymorphism (IRAP) was used to study the genetic variability in P. fijiensis populations from different hosts and different geographical origins in Brazil. A total of 22 loci were amplified and 77.3 % showed a polymorphism. Cluster analysis revealed two major groups in Brazil. The observed genetic diversity (H E) was 0.22, and through molecular analysis of variance, it was determined that the greatest genetic variability occurs within populations. The discriminant analysis of principal components revealed no structuring related to the geographical origin of culture of the host. The IRAP-based marker system is a suitable tool for the study of genetic variability in P. fijiensis.

  1. Analysis of Soccer Players’ Positional Variability During the 2012 UEFA European Championship: A Case Study

    Directory of Open Access Journals (Sweden)

    Moura Felipe Arruda

    2015-09-01

    Full Text Available The purpose of this study was to analyse players’ positional variability during the 2012 UEFA European Championship by applying principal component analysis (PCA to data gathered from heat maps posted on the UEFA website. We analysed the teams that reached the finals and semi-finals of the competition. The players’ 2D coordinates from each match were obtained by applying an image-processing algorithm to the heat maps. With all the players’ 2D coordinates for each match, we applied PCA to identify the directions of greatest variability. Then, two orthogonal segments were centred on each player’s mean position for all matches. The segments’ directions were driven by the eigenvectors of the PCA, and the length of each segment was defined as one standard deviation around the mean. Finally, an ellipse was circumscribed around both segments. To represent player variability, segment lengths and elliptical areas were analysed. The results demonstrate that Portugal exhibited the lowest variability, followed by Germany, Spain and Italy. Additionally, a graphical representation of every player’s ellipse provided insight into the teams’ organisational features throughout the competition. The presented study provides important information regarding soccer teams’ tactical strategy in high-level championships that allows coaches to better control team organisation on the pitch.

  2. Demographic Variables and Its Effect on Emotional Intelligence: A Study on Indian Service Sector Employees

    Science.gov (United States)

    Pooja, Pooja; Kumar, Pranab

    2016-01-01

    In past few decades, emotional intelligence (EI) has gained much popularity worldwide. Intelligence quotient alone is not enough in today's age for achieving success and hence for developing a person's ability, the fields of psychology and neurosciences have highlighted the importance of EI, which is a person's response toward feelings and emotions. In this study, relationship of various demographic variables with EI, as measured by Trait Emotional Intelligence Questionnaire-Short Form, has been highlighted. The study has been conducted on a sample of 424 employees belonging to the Indian service sector. The results showed that demographic variables have an impact over EI. Organizations can take a cue from the study and adhere to diversity management practices to ensure financial gains and growth. PMID:27536018

  3. Spatial variability studies in São Paulo, Brazil along the last twenty five years

    Directory of Open Access Journals (Sweden)

    Sidney Rosa Vieira

    2010-01-01

    Full Text Available Soil properties vary in space due to many causes. For this reason it is wise to know the magnitude and behaviour of the variability for adequate data analysis and decision making. Our work on spatial variability of soil properties in São Paulo, Brazil began in 1982 with a very simple soil sampling in a small field. Much progress has been made since then on sampling designs, field equipment and methods, and mostly on computation equipment and softwares. This paper reports the results corresponding to some aspects of this progress, as far as the field, analysis and computation work are concerned. The objective of this study was to illustrate the use of geostatistics in data analysis for three sampling conditions on long term no-tillage system. The analysis is done on a wide range of field scales, variables, sampling schemes as well as repeating sampling scheme for the same variable in different years. Semivariograms are compared for the same variables in different scales and sampling dates and depths as to provide a guide for sampling spacing and number of samples. Normalized crop yield parameters for many years are used in the discussion of time variability and on the use of yield maps to locate management zones. The time of the year in which measurements of soil physical properties are made affected the results both in terms of descriptive statistical and spatial dependence parameters. Crop yields changed (soybean decrease and maize increase with time of no-tillage but the real cause was not identified. The length of time with no-tillage affected the range of dependence for the main crops (increased for soybean, maize and oats and therefore increased the size of the homogeneous management zones. The evolution of the sampling grid from 20 m with 63 sampling points to 10 m with 302 sampling points allowed for a much better knowledge of the spatial variability of crop yields but it had the reverse effect on the spatial variability of soil physical

  4. Genetic and environmental influences on blood pressure variability: a study in twins.

    Science.gov (United States)

    Xu, Xiaojing; Ding, Xiuhua; Zhang, Xinyan; Su, Shaoyong; Treiber, Frank A; Vlietinck, Robert; Fagard, Robert; Derom, Catherine; Gielen, Marij; Loos, Ruth J F; Snieder, Harold; Wang, Xiaoling

    2013-04-01

    Blood pressure variability (BPV) and its reduction in response to antihypertensive treatment are predictors of clinical outcomes; however, little is known about its heritability. In this study, we examined the relative influence of genetic and environmental sources of variance of BPV and the extent to which it may depend on race or sex in young twins. Twins were enrolled from two studies. One study included 703 white twins (308 pairs and 87 singletons) aged 18-34 years, whereas another study included 242 white twins (108 pairs and 26 singletons) and 188 black twins (79 pairs and 30 singletons) aged 12-30 years. BPV was calculated from 24-h ambulatory blood pressure recording. Twin modeling showed similar results in the separate analysis in both twin studies and in the meta-analysis. Familial aggregation was identified for SBP variability (SBPV) and DBP variability (DBPV) with genetic factors and common environmental factors together accounting for 18-40% and 23-31% of the total variance of SBPV and DBPV, respectively. Unique environmental factors were the largest contributor explaining up to 82-77% of the total variance of SBPV and DBPV. No sex or race difference in BPV variance components was observed. The results remained the same after adjustment for 24-h blood pressure levels. The variance in BPV is predominantly determined by unique environment in youth and young adults, although familial aggregation due to additive genetic and/or common environment influences was also identified explaining about 25% of the variance in BPV.

  5. A genome-wide methylation study on obesity: differential variability and differential methylation.

    Science.gov (United States)

    Xu, Xiaojing; Su, Shaoyong; Barnes, Vernon A; De Miguel, Carmen; Pollock, Jennifer; Ownby, Dennis; Shi, Hidong; Zhu, Haidong; Snieder, Harold; Wang, Xiaoling

    2013-05-01

    Besides differential methylation, DNA methylation variation has recently been proposed and demonstrated to be a potential contributing factor to cancer risk. Here we aim to examine whether differential variability in methylation is also an important feature of obesity, a typical non-malignant common complex disease. We analyzed genome-wide methylation profiles of over 470,000 CpGs in peripheral blood samples from 48 obese and 48 lean African-American youth aged 14-20 y old. A substantial number of differentially variable CpG sites (DVCs), using statistics based on variances, as well as a substantial number of differentially methylated CpG sites (DMCs), using statistics based on means, were identified. Similar to the findings in cancers, DVCs generally exhibited an outlier structure and were more variable in cases than in controls. By randomly splitting the current sample into a discovery and validation set, we observed that both the DVCs and DMCs identified from the first set could independently predict obesity status in the second set. Furthermore, both the genes harboring DMCs and the genes harboring DVCs showed significant enrichment of genes identified by genome-wide association studies on obesity and related diseases, such as hypertension, dyslipidemia, type 2 diabetes and certain types of cancers, supporting their roles in the etiology and pathogenesis of obesity. We generalized the recent finding on methylation variability in cancer research to obesity and demonstrated that differential variability is also an important feature of obesity-related methylation changes. Future studies on the epigenetics of obesity will benefit from both statistics based on means and statistics based on variances.

  6. Kluyveromyces marxianus发酵己糖和戊糖生产乙醇%Ethanol production from hexose and pentose by Kluyveromyces marxianus

    Institute of Scientific and Technical Information of China (English)

    韩锡铜; 高教琪; 陈丽杰; 袁文杰; 白凤武

    2015-01-01

    Kluyveromyces marxianus DL1 and Saccharomyces cerevisiae 6525 were compared by using hexose (glucose, mannose and galactose) and pentose (xylose and arabinose) as substrates. When hexoses were used as substrates, K. marxianus showed the characteristic of fast growth and higher ethanol yield. Under the condition of anaerobic and 20 g/L sugar concentration, the ethanol concentration of K. marxianus DL1 was 10% higher than that of S. cerevisiae 6525, and the biomass and the ethanol productivity of K. marxianus DL1 were 2 and 1�7 times to that of S. cerevisiae 6525� When pentoses were used as the substrate under the conditions of anaerobic and 20 g/L sugar concentration, S. cerevisiae 6525 could not use pentoses whereas K. marxianus DL1 could use xylose to produce ethanol and xylitol, and the concentration reached 7�68 g/L and 9�12 g/L, respectively. K. marxianus DL1 could also ferment arabinose to produce 6 g/L arabitol. K. marxianus DL1 is more suitable for cellulosic ethanol production than Saccharomyces cerevisiae.%对利用底物广泛的乙醇发酵菌株马克斯克鲁维( Kluyveromyces marxianus) DL1菌株与工业用乙醇发酵菌株酿酒酵母(Saccharomyces cerevisiae)6525利用己糖(葡萄糖、甘露糖、半乳糖)和戊糖(木糖、阿拉伯糖)的情况进行对比研究。结果发现:以己糖为底物时,K�marxianus DL1均表现出细胞生长快、乙醇得率高的特点;在不通气、糖20 g/L条件下,K�marxianus DL1的最大乙醇质量浓度均比S�cerevisiae 6525高出10%左右,细胞量及乙醇生产强度分别是S�cerevisiae 6525的近2和1�7倍。当以戊糖为底物时,K�marxianus DL1可以利用木糖和阿拉伯糖;在不通气、糖20 g/L条件下,K�marxianus DL1利用木糖产木糖醇和乙醇,乙醇终质量浓度可达7�68 g/L,木糖醇质量浓度为9�12 g/L;以阿拉伯糖为发酵底物时,阿拉伯糖醇的产量可达6 g

  7. Study on distributed generation algorithm of variable precision concept lattice based on ontology heterogeneous database

    Science.gov (United States)

    WANG, Qingrong; ZHU, Changfeng

    2017-06-01

    Integration of distributed heterogeneous data sources is the key issues under the big data applications. In this paper the strategy of variable precision is introduced to the concept lattice, and the one-to-one mapping mode of variable precision concept lattice and ontology concept lattice is constructed to produce the local ontology by constructing the variable precision concept lattice for each subsystem, and the distributed generation algorithm of variable precision concept lattice based on ontology heterogeneous database is proposed to draw support from the special relationship between concept lattice and ontology construction. Finally, based on the standard of main concept lattice of the existing heterogeneous database generated, a case study has been carried out in order to testify the feasibility and validity of this algorithm, and the differences between the main concept lattice and the standard concept lattice are compared. Analysis results show that this algorithm above-mentioned can automatically process the construction process of distributed concept lattice under the heterogeneous data sources.

  8. Anatomy of the AGN in NGC 5548: VII. Swift study of obscuration and broadband continuum variability

    CERN Document Server

    Mehdipour, M; Kriss, G A; Cappi, M; Petrucci, P -O; De Marco, B; Ponti, G; Steenbrugge, K C; Behar, E; Bianchi, S; Branduardi-Raymont, G; Costantini, E; Ebrero, J; Di Gesu, L; Matt, G; Paltani, S; Peterson, B M; Ursini, F; Whewell, M

    2016-01-01

    We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670 ks of observing time. Both broadband spectral modelling and temporal rms variability analysis are applied to the Swift data. We disentangle the variability caused by absorption, due to an obscuring weakly-ionised outflow near the disk, from variability of the intrinsic continuum components (the soft X-ray excess and the power-law) originating from the disk and its associated coronae. The spectral model that we apply to this extensive Swift data is the global model that we derived for NGC 5548 from analysis of the stacked spectra from our multi-satellite campaign of summer 2013 (including XMM-Newton, NuSTAR and HST). The results of our Swift study show that changes in the covering fraction of the obscurer is...

  9. A study of soil moisture variability for landmine detection by the neutron technique

    Directory of Open Access Journals (Sweden)

    Avdić Senada

    2007-01-01

    Full Text Available This paper is focused on the space and temporal variability of soil moisture experimental data acquired at a few locations near landmine fields in the Tuzla Canton, as well as on the quantification of the statistical nature of soil moisture data on a small spatial scale. Measurements of soil water content at the surface were performed by an electro-magnetic sensor over 1 25, and 100 m2 grids, at intervals of 0.2, 0.5, and 1 m, respectively. The sampling of soil moisture at different spatial resolutions and over different grid sizes has been investigated in order to achieve the quantification of the statistical nature of soil moisture distribution. The statistical characterization of spatial variability was performed through variogram and correlogram analysis of measurement results. The temporal variability of the said samples was examined over a two-season period. For both sampling periods, the spatial correlation length is about 1 to 2 m, respectively, or less. Thus, sampling should be done on a larger spatial scale, in order to capture the variability of the investigated areas. Since the characteristics of many landmine sensors depend on soil moisture, the results of this study could form a useful data base for multisensor landmine detection systems with a promising performance.

  10. Hydrogen isotope variability in prairie wetland systems: implications for studies of migratory connectivity.

    Science.gov (United States)

    Bortolotti, Lauren E; Clark, Robert G; Wassenaar, Leonard I

    2013-01-01

    Hydrogen isotopes (delta2H) are often used to infer the origins of migratory animals based on the strong correlation between deuterium content of tissues and long-term patterns of precipitation. However, the extreme flood and drought dynamics of surface waters in prairie wetland systems could mask these expected correlations. We investigated H isotopic variability in an aquatic food web associated with Tree Swallows (Tachycineta bicolor) that rely heavily on wetland-derived aerial insects for food. We evaluated isotopic turnover and incorporation of environmental water into tissue, processes that could affect H isotopic composition. Wetland water and aquatic invertebrates showed intra- and interannual H isotopic variation mainly related to evaporation and the amount and timing of precipitation. Snails showed rapid turnover of tissue deuterium and a large contribution of environmental water to their tissues. Swallow feather deuterium (delta2Hf) was variable but did not clearly follow changes in any of the food web compartments measured. Instead, isotopic variability may have been driven by shifts in the type or relative amounts of grey consumed and types of wetlands used. Nevertheless, despite relatively high variance in delta2Hf, the majority of birds fell within the predicted range of delta2Hf for the study area, revealing that significant trophic averaging occurred. However, both (presumed) diet shifts and variable hydrological conditions have the potential to greatly increase variance that must be considered when assigning origins of migratory animals based on delta2H.

  11. Field Scale Studies on the Spatial Variability of Soil Quality Indicators in Washington State, USA

    Directory of Open Access Journals (Sweden)

    Jeffrey L. Smith

    2011-01-01

    Full Text Available Arable lands are needed for sustainable agricultural systems to support an ever-growing human population. Soil quality needs to be defined to assure that new land brought into crop production is sustainable. To evaluate soil quality, a number of soil attributes will need to be measured, evaluated, and integrated into a soil-quality index using the multivariable indicator kriging (MVIK procedure. This study was conducted to determine the spatial variability and correlation of indicator parameters on a field scale with respect to soil quality and suitability for use with MVIK. The variability of the biological parameters decreased in the order of respiration > enzyme assays and qCO2 > microbial biomass C. The distribution frequency of all parameters except respiration were normal although the spatial distribution across the landscape was highly variable. The biological parameters showed little correlation with each other when all data points were considered; however, when grouped in smaller sections, the correlations were more consistent with observed patterns across the field. To accurately assess soil quality, and arable land use, consideration of spatial and temporal variability, soil conditions, and other controlling factors must be taken into account.

  12. A photometric variability study of massive stars in Cygnus OB2

    CERN Document Server

    Salas, J; Barbá, R H

    2014-01-01

    We have conducted a 1.5 year-long variability study of the stars in the Cygnus OB2 association, the region in the northern hemisphere with the highest density of optically visible massive stars. The survey was conducted using four pointings in the Johnson $R$ and $I$ bands with a 35 cm Meade LX200-ACF telescope equipped with a 3.2 Mpixel SBIG ST10-XME CCD camera and includes 300+ epochs in each filter. A total of 1425 objects were observed with limiting magnitudes of 15 in $R$ and 14 in $I$. The photometry was calibrated using reference stars with existing $UBVJHK$ photometry. Bright stars have precisions better than 0.01 magnitudes, allowing us to detect 52 confirmed and 19 candidate variables, many of them massive stars without previous detections as variables. Variables are classified as eclipsing, pulsating, irregular/long period, and Be. We derive the phased light curves for the eclipsing binaries, with periods ranging from 1.3 to 8.5 days.

  13. Posttranslational elevation of cell wall invertase activity by silencing its inhibitor in tomato delays leaf senescence and increases seed weight and fruit hexose level.

    Science.gov (United States)

    Jin, Ye; Ni, Di-An; Ruan, Yong-Ling

    2009-07-01

    Invertase plays multiple pivotal roles in plant development. Thus, its activity must be tightly regulated in vivo. Emerging evidence suggests that a group of small proteins that inhibit invertase activity in vitro appears to exist in a wide variety of plants. However, little is known regarding their roles in planta. Here, we examined the function of INVINH1, a putative invertase inhibitor, in tomato (Solanum lycopersicum). Expression of a INVINH1:green fluorescent protein fusion revealed its apoplasmic localization. Ectopic overexpression of INVINH1 in Arabidopsis thaliana specifically reduced cell wall invertase activity. By contrast, silencing its expression in tomato significantly increased the activity of cell wall invertase without altering activities of cytoplasmic and vacuolar invertases. Elevation of cell wall invertase activity in RNA interference transgenic tomato led to (1) a prolonged leaf life span involving in a blockage of abscisic acid-induced senescence and (2) an increase in seed weight and fruit hexose level, which is likely achieved through enhanced sucrose hydrolysis in the apoplasm of the fruit vasculature. This assertion is based on (1) coexpression of INVINH1 and a fruit-specific cell wall invertase Lin5 in phloem parenchyma cells of young fruit, including the placenta regions connecting developing seeds; (2) a physical interaction between INVINH1 and Lin5 in vivo; and (3) a symplasmic discontinuity at the interface between placenta and seeds. Together, the results demonstrate that INVINH1 encodes a protein that specifically inhibits the activity of cell wall invertase and regulates leaf senescence and seed and fruit development in tomato by limiting the invertase activity in planta.

  14. Studies on inter-speaker variability in speech and its application in automatic speech recognition

    Indian Academy of Sciences (India)

    S Umesh

    2011-10-01

    In this paper, we give an overview of the problem of inter-speaker variability and its study in many diverse areas of speech signal processing. We first give an overview of vowel-normalization studies that minimize variations in the acoustic representation of vowel realizations by different speakers. We then describe the universal-warping approach to speaker normalization which unifies many of the vowel normalization approaches and also shows the relation between speech production, perception and auditory processing. We then address the problem of inter-speaker variability in automatic speech recognition (ASR) and describe techniques that are used to reduce these effects and thereby improve the performance of speaker-independent ASR systems.

  15. Spectral Kernel Approach to Study Radiative Response of Climate Variables and Interannual Variability of Reflected Solar Spectrum

    Science.gov (United States)

    Jin, Zhonghai; Wielicki, Bruce A.; Loukachine, Constantin; Charlock, Thomas P.; Young, David; Noeel, Stefan

    2011-01-01

    The radiative kernel approach provides a simple way to separate the radiative response to different climate parameters and to decompose the feedback into radiative and climate response components. Using CERES/MODIS/Geostationary data, we calculated and analyzed the solar spectral reflectance kernels for various climate parameters on zonal, regional, and global spatial scales. The kernel linearity is tested. Errors in the kernel due to nonlinearity can vary strongly depending on climate parameter, wavelength, surface, and solar elevation; they are large in some absorption bands for some parameters but are negligible in most conditions. The spectral kernels are used to calculate the radiative responses to different climate parameter changes in different latitudes. The results show that the radiative response in high latitudes is sensitive to the coverage of snow and sea ice. The radiative response in low latitudes is contributed mainly by cloud property changes, especially cloud fraction and optical depth. The large cloud height effect is confined to absorption bands, while the cloud particle size effect is found mainly in the near infrared. The kernel approach, which is based on calculations using CERES retrievals, is then tested by direct comparison with spectral measurements from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) (a different instrument on a different spacecraft). The monthly mean interannual variability of spectral reflectance based on the kernel technique is consistent with satellite observations over the ocean, but not over land, where both model and data have large uncertainty. RMS errors in kernel ]derived monthly global mean reflectance over the ocean compared to observations are about 0.001, and the sampling error is likely a major component.

  16. The role of ocean velocity in chlorophyll variability. A modelling study in the Alboran Sea

    OpenAIRE

    Solé, Jordi; Ballabrera-Poy, Joaquim; Macías, Diego; Catalán, Ignacio A.

    2016-01-01

    In this work we focus on the Alboran Sea (western Mediterranean) to relate wind field and ocean velocity variability with chlorophyll a (Chl a) behaviour, using a 2-km resolution, coupled 3D ocean circulation-NPZD model (ROMS). The analysis is done in three steps. First, we split the seasonal and residual contribution for the fields under study. Second, we calculate the corresponding empirical orthogonal functions (EOFs) for the seasonal and residual parts. Finally, we relate each pair of var...

  17. Cephalometric landmark variability among orthodontists and dentomaxillofacial radiologists: a comparative study

    OpenAIRE

    2015-01-01

    Purpose The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks. Materials and Methods Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for ea...

  18. A modelling study of photochemical regimes over Europe: robustness and variability

    Directory of Open Access Journals (Sweden)

    M. Beekmann

    2010-10-01

    Full Text Available The variability of the relative sensitivity of photochemical ozone formation to volatile organic compounds (VOC and NOx emissions, the chemical regime, over Europe during summers 2001 to 2003 is simulated with a regional scale transport-chemistry model. The robustness and variability of chemical regimes is shown. A VOC sensitive regime over North-Western Europe and a mainly NOx sensitive regime over the Mediterranean basin and Eastern Europe are found, confirming earlier published results. The chemical regime time variability, its robustness with respect to several environmental factors (seasonality, interannual variability and with respect to model uncertainty are thoroughly analysed. For the regions with well pronounced chemical regimes over North-Western Europe and the Mediterranean, the chemical regime occurrence only slightly depends on the ozone target considered – daily ozone or Ox (= O3 + NO2 maximum or mean, AOT's, SOMO35, .... For these regions, differences between particular years and summer months are weak, day to day variability is significant but does not change the occurrence of one or another chemical regime. On the contrary, over North-Eastern Germany, the chemical regime changes form one day to another and is also dependent on the ozone target chosen. Expected decreases in anthropogenic NOx emissions over Europe since the last and for the next few decades have shifted and will shift chemical regimes to more NOx sensitive. The predictive skill of chemical regime indicator species is made evident at continental scale, extending their spatial range of applicability with respect to earlier studies. Several sensitivity tests were performed in order to account for major sources of model uncertainty. With the exception of regions near ship tracks over the Mediterranean basin, the spatial pattern of chemical regimes appears to be robust with respect to model

  19. Statistical and methodological problems with concreteness and other semantic variables: A list memory experiment case study.

    Science.gov (United States)

    Pollock, Lewis

    2017-07-13

    The purpose of this article is to highlight problems with a range of semantic psycholinguistic variables (concreteness, imageability, individual modality norms, and emotional valence) and to provide a way of avoiding these problems. Focusing on concreteness, I show that for a large class of words in the Brysbaert, Warriner, and Kuperman (Behavior Research Methods 46: 904-911, 2013) concreteness norms, the mean concreteness values do not reflect the judgments that actual participants made. This problem applies to nearly every word in the middle of the concreteness scale. Using list memory experiments as a case study, I show that many of the "abstract" stimuli in concreteness experiments are not unequivocally abstract. Instead, they are simply those words about which participants tend to disagree. I report three replications of list memory experiments in which the contrast between concrete and abstract stimuli was maximized, so that the mean concreteness values were accurate reflections of participants' judgments. The first two experiments did not produce a concreteness effect. After I introduced an additional control, the third experiment did produce a concreteness effect. The article closes with a discussion of the implications of these results, as well as a consideration of variables other than concreteness. The sensorimotor experience variables (imageability and individual modality norms) show the same distribution as concreteness. The distribution of emotional valence scores is healthier, but variability in ratings takes on a special significance for this measure because of how the scale is constructed. I recommend that researchers using these variables keep the standard deviations of the ratings of their stimuli as low as possible.

  20. Optimization under variability and uncertainty: a case study for NOx emissions control for a gasification system.

    Science.gov (United States)

    Chen, Jianjun; Frey, H Christopher

    2004-12-15

    Methods for optimization of process technologies considering the distinction between variability and uncertainty are developed and applied to case studies of NOx control for Integrated Gasification Combined Cycle systems. Existing methods of stochastic optimization (SO) and stochastic programming (SP) are demonstrated. A comparison of SO and SP results provides the value of collecting additional information to reduce uncertainty. For example, an expected annual benefit of 240,000 dollars is estimated if uncertainty can be reduced before a final design is chosen. SO and SP are typically applied to uncertainty. However, when applied to variability, the benefit of dynamic process control is obtained. For example, an annual savings of 1 million dollars could be achieved if the system is adjusted to changes in process conditions. When variability and uncertainty are treated distinctively, a coupled stochastic optimization and programming method and a two-dimensional stochastic programming method are demonstrated via a case study. For the case study, the mean annual benefit of dynamic process control is estimated to be 700,000 dollars, with a 95% confidence range of 500,000 dollars to 940,000 dollars. These methods are expected to be of greatest utility for problems involving a large commitment of resources, for which small differences in designs can produce large cost savings.

  1. SVAw - a web-based application tool for automated surrogate variable analysis of gene expression studies.

    Science.gov (United States)

    Pirooznia, Mehdi; Seifuddin, Fayaz; Goes, Fernando S; Leek, Jeffrey T; Zandi, Peter P

    2013-03-11

    Surrogate variable analysis (SVA) is a powerful method to identify, estimate, and utilize the components of gene expression heterogeneity due to unknown and/or unmeasured technical, genetic, environmental, or demographic factors. These sources of heterogeneity are common in gene expression studies, and failing to incorporate them into the analysis can obscure results. Using SVA increases the biological accuracy and reproducibility of gene expression studies by identifying these sources of heterogeneity and correctly accounting for them in the analysis. Here we have developed a web application called SVAw (Surrogate variable analysis Web app) that provides a user friendly interface for SVA analyses of genome-wide expression studies. The software has been developed based on open source bioconductor SVA package. In our software, we have extended the SVA program functionality in three aspects: (i) the SVAw performs a fully automated and user friendly analysis workflow; (ii) It calculates probe/gene Statistics for both pre and post SVA analysis and provides a table of results for the regression of gene expression on the primary variable of interest before and after correcting for surrogate variables; and (iii) it generates a comprehensive report file, including graphical comparison of the outcome for the user. SVAw is a web server freely accessible solution for the surrogate variant analysis of high-throughput datasets and facilitates removing all unwanted and unknown sources of variation. It is freely available for use at http://psychiatry.igm.jhmi.edu/sva. The executable packages for both web and standalone application and the instruction for installation can be downloaded from our web site.

  2. Multiple dose bioequivalence study with josamycin propionate, a drug with highly variable kinetics, in healthy volunteers.

    Science.gov (United States)

    Van Hoogdalem, E J; Terpstra, I J; Krauwinkel, W J; Volkers-Kamermans, N J; Baven, A L; Verschoor, J S

    1996-05-01

    Josamycin is a macrolide antibiotic with considerable intra- and interindividual variability in kinetics. In the present study bioequivalence of an intact and dispersed josamycin Solutab tablet, containing 1,000 mg of josamycin in the form of josamycin propionate ester, was tested versus a Josacine 1,000 mg reference sachet. The design of this bioequivalence study was adapted to the drug's pharmacokinetic variability, comprising testing in steady-state, testing the reference in replicate, and maintaining a widened bioequivalence margin. The study was performed in a group of 24 male and 12 female healthy subjects, according to a 3-treatment 4-period crossover design. Blood sampling for establishing josamycin propionate and josamycin base serum level profiles were collected during the 12 h dosing interval on day 4. Steady-state serum levels were reached on day 4. With the reference sachet mean peak levels of 1.02 micrograms/ml and 0.36 microgram/ml were observed for parent drug and metabolite, respectively, reached at peak times of 1.5 h and 1.8 h. Comparable profiles were observed with the intact and dispersed Solutab tablets, both tending towards higher serum levels than the sachet. In terms of josamycin propionate levels as well as josamycin base levels, the intact and dispersed Solutab tablet was bioequivalent with the referent sachet within the preset 0.70-1.43 margins. Variability in josamycin kinetics proved to be substantial, maximum differences in peak levels and AUC values being about 10-fold between individuals, and 3-fold within individuals. Retrospectively, the multiple dosing regimen appeared not to result in a clear reduction of intrasubject variability.

  3. Variability of Creatinine Measurements in Clinical Laboratories: Results from the CRIC Study

    Science.gov (United States)

    Joffe, Marshall; Hsu, Chi-yuan; Feldman, Harold I.; Weir, Matthew; Landis, J.R.; Hamm, L. Lee

    2010-01-01

    Objectives Estimating equations using serum creatinine (SCr) are often used to assess glomerular filtration rate (GFR). Such creatinine (Cr)-based formulae may produce biased estimates of GFR when using Cr measurements that have not been calibrated to reference laboratories. In this paper, we sought to examine the degree of this variation in Cr assays in several laboratories associated with academic medical centers affiliated with the Chronic Renal Insufficiency Cohort (CRIC) Study; to consider how best to correct for this variation, and to quantify the impact of such corrections on eligibility for participation in CRIC. Variability of Cr is of particular concern in the conduct of CRIC, a large multicenter study of subjects with chronic renal disease, because eligibility for the study depends on Cr-based assessment of GFR. Methods A library of 5 large volume plasma specimens from apheresis patients was assembled, representing levels of plasma Cr from 0.8 to 2.4 mg/dl. Samples from this library were used for measurement of Cr at each of the 14 CRIC laboratories repetitively over time. We used graphical displays and linear regression methods to examine the variability in Cr, and used linear regression to develop calibration equations. We also examined the impact of the various calibration equations on the proportion of subjects screened as potential participants who were actually eligible for the study. Results There was substantial variability in Cr assays across laboratories and over time. We developed calibration equations for each laboratory; these equations varied substantially among laboratories and somewhat over time in some laboratories. The laboratory site contributed the most to variability (51% of the variance unexplained by the specimen) and variation with time accounted for another 15%. In some laboratories, calibration equations resulted in differences in eligibility for CRIC of as much as 20%. Conclusions The substantial variability in SCr assays

  4. Patients' Evaluations of Complete Denture Therapy and Their Association with Related Variables: A Pilot Study.

    Science.gov (United States)

    Santos, Beatriz Ferreira Oliveira; dos Santos, Mateus Bertolini Fernandes; Santos, Jarbas Francisco Fernandes; Marchini, Leonardo

    2015-07-01

    Patient satisfaction is an important goal in complete denture therapy, and many factors influence this parameter. This study aimed to evaluate expectations before and satisfaction after therapy with complete dentures. As a secondary objective, other variables that may interfere with patient satisfaction were also evaluated. A representative sample of 99 patients assigned visual analog scale (VAS) scores to their expectations before and satisfaction after therapy regarding chewing, esthetics, comfort, and phonetics. Demographic data and answers to a questionnaire concerning the dentists' conduct were recorded. Multiple linear regression was used to evaluate the association among studied variables and patients' expectation and satisfaction with their dentures. The average VAS scores were high for both expectations and satisfaction, and satisfaction exceeded expectations. Patients' expectations about esthetics and comfort were associated with age and self-reported time of using complete dentures. Patient satisfaction regarding chewing was associated with the number of postdelivery adjustments. Also, patient satisfaction regarding esthetics was associated with gender and esthetic expectations. In regard to phonetic satisfaction, associations were verified among self-reported time of using complete dentures, comfort and phonetics expectations, and dentists' explanations. Comfort satisfaction was associated only with educational level. Patient satisfaction regarding complete dentures exceeded expectations and an expressive majority of positive evaluations of the dentists was noticed. Many patient-related variables seemed to influence their evaluations of their dentures. © 2015 by the American College of Prosthodontists.

  5. INTRODUCING INSTITUTIONAL VARIABLES IN THE ENVIRONMENTAL KUZNETS CURVE (EKC: A LATIN AMERICAN STUDY

    Directory of Open Access Journals (Sweden)

    ITALO ARBULÚ VILLANUEVA

    2012-03-01

    Full Text Available Several studies have examined the relationship between environmental degradation and per capita income.However, most of them did not take into account institutional quality and just focused on macroeconomicdeterminants. The purpose of this paper is to fill this gap in the literature by assessing the effects on theEnvironmental Kuznets Curve (EKC when institutional quality variables are introduced, especially those related tocorruption and rent-seeking behavior.This study considers 18 Latin American economies and panel data for 1998–2005. A standard reducedformmodeling approach with pool estimation was employed and, in order to introduce the heterogeneity of thedifferent countries, three different models were estimated. The first model corresponds to the basic EnvironmentalKuznets Curve (Basic Model, the second model introduced a sets of additional economic variables (ExtendedModel Nº 1, and finally, the third one introduced institutional variables into the previous formulation (ExtendedModel Nº 2.The expected results from this investigation lead us to support the EKC hypothesis while confirming theimportance of improvements in political institutions and governance for better environmental performances in theregion.

  6. An experimental study of variable depth search algorithms for the quadratic assignment problem

    Directory of Open Access Journals (Sweden)

    Elizabeth Ferreira Gouvêa Goldbarg

    2012-04-01

    Full Text Available This paper introduces a new variable depth search method for the Quadratic Assignment Problem. The new method considers the cost of edges assignment as the criterion to decide which vertices to exchange during local search moves. It also presents the results of an extensive experimental study that compares the performance of local search and variable depth search algorithms for the Quadratic Assignment Problem. The investigation presented here contributes to a better understanding of the potential of these techniques, which are widely used as intensification tools in more sophisticated heuristic methods, such as evolutionary algorithms. Different algorithms presented in the literature were implemented and compared to the proposed methods. The results of a computational experiment with 161 benchmark instances are reported. Different statistical tests are applied in order to analyze the results provided by the experiments.

  7. Rank correlation plots for use with correlated input variables in simulation studies

    Energy Technology Data Exchange (ETDEWEB)

    Iman, R.L.; Davenport, J.M.

    1980-11-01

    A method for inducing a desired rank correlation matrix on multivariate input vectors for simulation studies has recently been developed by Iman and Conover (SAND 80-0157). The primary intention of this procedure is to produce correlated input variables for use with computer models. Since this procedure is distribution free and allows the exact marginal distributions to remain intact, it can be used with any marginal distributions for which it is reasonable to think in terms of correlation. A series of rank correlation plots based on this procedure when the marginal distributions are normal, lognormal, uniform, and loguniform is presented. These plots provide a convenient tool for both aiding the modeler in determining the degree of dependence among variables (rather than guessing) and communicating with the modeler the effect of different correlation assumptions. 12 figures, 10 tables.

  8. X-RAY VARIABILITY STUDY OF POLAR SCATTERED SEYFERT1 GALAXIES

    Directory of Open Access Journals (Sweden)

    Tobias Beuchert

    2014-08-01

    Full Text Available We study 12 Seyfert 1 galaxies with a high level of optical polarization. Optical light emerging from the innermost regions is predominantly scattered in a polar region above the central engine directly in our line of sight. These sources show characteristics of Seyfert 2 galaxies, e.g. polarized broad lines. The polarization signatures suggest a viewing angle of 45°, classifying them as intermediate Seyfert 1/2 types. The unified model predicts this line of sight to pass through the outer layer of the torus resulting in significant soft X-ray variability due to a strongly varying column density. The aim is to find evidence for this geometrical assumption in the spectral variability of all available historical observations of these sources by XMM-Newton and Swift.

  9. Bayesian latent variable models for hierarchical clustered count outcomes with repeated measures in microbiome studies.

    Science.gov (United States)

    Xu, Lizhen; Paterson, Andrew D; Xu, Wei

    2017-04-01

    Motivated by the multivariate nature of microbiome data with hierarchical taxonomic clusters, counts that are often skewed and zero inflated, and repeated measures, we propose a Bayesian latent variable methodology to jointly model multiple operational taxonomic units within a single taxonomic cluster. This novel method can incorporate both negative binomial and zero-inflated negative binomial responses, and can account for serial and familial correlations. We develop a Markov chain Monte Carlo algorithm that is built on a data augmentation scheme using Pólya-Gamma random variables. Hierarchical centering and parameter expansion techniques are also used to improve the convergence of the Markov chain. We evaluate the performance of our proposed method through extensive simulations. We also apply our method to a human microbiome study.

  10. REDUCING PROCESS VARIABILITY BY USING DMAIC MODEL: A CASE STUDY IN BANGLADESH

    Directory of Open Access Journals (Sweden)

    Ripon Kumar Chakrabortty

    2013-03-01

    Full Text Available Now-a-day's many leading manufacturing industry have started to practice Six Sigma and Lean manufacturing concepts to boost up their productivity as well as quality of products. In this paper, the Six Sigma approach has been used to reduce process variability of a food processing industry in Bangladesh. DMAIC (Define,Measure, Analyze, Improve, & Control model has been used to implement the Six Sigma Philosophy. Five phases of the model have been structured step by step respectively. Different tools of Total Quality Management, Statistical Quality Control and Lean Manufacturing concepts likely Quality function deployment, P Control chart, Fish-bone diagram, Analytical Hierarchy Process, Pareto analysis have been used in different phases of the DMAIC model. The process variability have been tried to reduce by identify the root cause of defects and reducing it. The ultimate goal of this study is to make the process lean and increase the level of sigma.

  11. Comparative Study of Monsoon Rainfall Variability over India and the Odisha State

    Directory of Open Access Journals (Sweden)

    K C Gouda

    2017-10-01

    Full Text Available Indian summer monsoon (ISM plays an important role in the weather and climate system over India. The rainfall during monsoon season controls many sectors from agriculture, food, energy, and water, to the management of disasters. Being a coastal province on the eastern side of India, Odisha is one of the most important states affected by the monsoon rainfall and associated hydro-meteorological systems. The variability of monsoon rainfall is highly unpredictable at multiple scales both in space and time. In this study, the monsoon variability over the state of Odisha is studied using the daily gridded rainfall data from India Meteorological Department (IMD. A comparative analysis of the behaviour of monsoon rainfall at a larger scale (India, regional scale (Odisha, and sub-regional scale (zones of Odisha is carried out in terms of the seasonal cycle of monsoon rainfall and its interannual variability. It is seen that there is no synchronization in the seasonal monsoon category (normal/excess/deficit when analysed over large (India and regional (Odisha scales. The impact of El Niño, La Niña, and the Indian Ocean Dipole (IOD on the monsoon rainfall at both scales (large scale and regional scale is analysed and compared. The results show that the impact is much more for rainfall over India, but it has no such relation with the rainfall over Odisha. It is also observed that there is a positive (negative relation of the IOD with the seasonal monsoon rainfall variability over Odisha (India. The correlation between the IAV of monsoon rainfall between the large scale and regional scale was found to be 0.46 with a phase synchronization of 63%. IAV on a sub-regional scale is also presented.

  12. Variability in avian eggshell colour: a comparative study of museum eggshells.

    Directory of Open Access Journals (Sweden)

    Phillip Cassey

    Full Text Available BACKGROUND: The exceptional diversity of coloration found in avian eggshells has long fascinated biologists and inspired a broad range of adaptive hypotheses to explain its evolution. Three main impediments to understanding the variability of eggshell appearance are: (1 the reliable quantification of the variation in eggshell colours; (2 its perception by birds themselves, and (3 its relation to avian phylogeny. Here we use an extensive museum collection to address these problems directly, and to test how diversity in eggshell coloration is distributed among different phylogenetic levels of the class Aves. METHODOLOGY AND RESULTS: Spectrophotometric data on eggshell coloration were collected from a taxonomically representative sample of 251 bird species to determine the change in reflectance across different wavelengths and the taxonomic level where the variation resides. As many hypotheses for the evolution of eggshell coloration assume that egg colours provide a communication signal for an avian receiver, we also modelled reflectance spectra of shell coloration for the avian visual system. We found that a majority of species have eggs with similar background colour (long wavelengths but that striking differences are just as likely to occur between congeners as between members of different families. The region of greatest variability in eggshell colour among closely related species coincided with the medium-wavelength sensitive region around 500 nm. CONCLUSIONS: The majority of bird species share similar background eggshell colours, while the greatest variability among species aligns with differences along a red-brown to blue axis that most likely corresponds with variation in the presence and concentration of two tetrapyrrole pigments responsible for eggshell coloration. Additionally, our results confirm previous findings of temporal changes in museum collections, and this will be of particular concern for studies testing intraspecific

  13. Variability in avian eggshell colour: a comparative study of museum eggshells.

    Science.gov (United States)

    Cassey, Phillip; Portugal, Steven J; Maurer, Golo; Ewen, John G; Boulton, Rebecca L; Hauber, Mark E; Blackburn, Tim M

    2010-08-09

    The exceptional diversity of coloration found in avian eggshells has long fascinated biologists and inspired a broad range of adaptive hypotheses to explain its evolution. Three main impediments to understanding the variability of eggshell appearance are: (1) the reliable quantification of the variation in eggshell colours; (2) its perception by birds themselves, and (3) its relation to avian phylogeny. Here we use an extensive museum collection to address these problems directly, and to test how diversity in eggshell coloration is distributed among different phylogenetic levels of the class Aves. Spectrophotometric data on eggshell coloration were collected from a taxonomically representative sample of 251 bird species to determine the change in reflectance across different wavelengths and the taxonomic level where the variation resides. As many hypotheses for the evolution of eggshell coloration assume that egg colours provide a communication signal for an avian receiver, we also modelled reflectance spectra of shell coloration for the avian visual system. We found that a majority of species have eggs with similar background colour (long wavelengths) but that striking differences are just as likely to occur between congeners as between members of different families. The region of greatest variability in eggshell colour among closely related species coincided with the medium-wavelength sensitive region around 500 nm. The majority of bird species share similar background eggshell colours, while the greatest variability among species aligns with differences along a red-brown to blue axis that most likely corresponds with variation in the presence and concentration of two tetrapyrrole pigments responsible for eggshell coloration. Additionally, our results confirm previous findings of temporal changes in museum collections, and this will be of particular concern for studies testing intraspecific hypotheses relating temporal patterns to adaptation of eggshell colour

  14. Kinetic analysis of hexose transport to determine the mechanism of amygdalin and prunasin absorption in the intestine.

    Science.gov (United States)

    Wagner, Brent; Galey, William R

    2003-01-01

    Evidence is accumulating that glucose-conjugated compounds may be carried across the gut mucosa via the epithelial sodium-dependent monosaccharide transporter SGLT1. A modification of the everted intestinal sac technique was utilized to study the transport of the cyanogenic glycoside amygdalin (D-mandelonitrile beta-D-gentiobioside) and its metabolite D-mandelontrile beta-D-glucoside (prunasin). Everted sacs of rat jejunum and ileum were bathed in isotonic oxygenated sodium chloride-potassium phosphate buffer containing 2.8 microCi D-[(3)H]-mannose and 0.187 microCi D-[(14)C]-glucose. For treatment groups, buffers contained phloridzin, galactose, amygdalin or prunasin. The rate constant (k) for the transport process was calculated. Compared with the control (n = 33), phloridzin (n = 25) significantly reduced the rate constants of both D-[(14)C]-glucose and D-[(3)H]-mannose. Substitution of sodium with choline and incremental galactose treatments similarly reduced D-[(14)C]-glucose influx, indicating that a fraction of the transport is carrier-mediated. Treatment with amygdalin did not significantly affect the rate constants of D-[(14)C]-glucose or D-[(3)H]-mannose transport. However, treatment with 1 mM prunasin (n = 16) did reduce the influx of D-[(14)C]-glucose without affecting D-[(3)H]-mannose values. This is consistent with the reports finding that glycoside absorption may be mediated by SGLT1. Copyright 2003 John Wiley & Sons, Ltd.

  15. Activation of pyrophosphate:fructose-6-phosphate 1-phosphotransferase by fructose 2,6-bisphosphate stimulates conversion of hexose phosphates to triose phosphates but does not influence accumulation of carbohydrates in phosphate-deficient tobacco cells.

    Science.gov (United States)

    Fernie, Alisdair R; Roscher, Albrecht; Ratcliffe, R. George; Kruger, Nicholas J

    2002-02-01

    The aim of this work was to investigate the contribution of fructose 2,6-bisphosphate to the regulation of carbohydrate metabolism under phosphate stress. The study exploited heterotrophic tobacco callus lines expressing a modified mammalian 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase that increased the fructose 2,6-bisphosphate content of the tissue. The phosphate status of two transgenic and one untransformed cell line was perturbed by incubation with 2-deoxyglucose, a phosphate-sequestering agent, and by growth of callus on phosphate-depleted media. 31P-NMR spectroscopy confirmed that both treatments decreased cellular levels of inorganic phosphate and phosphorylated metabolites. Despite large decreases in the amounts of phosphate esters, UDPglucose and adenylates in response to phosphate deficiency, the fructose 2,6-bisphosphate content of each line was unaffected by 2-deoxyglucose and increased during growth on phosphate-limited media. Short-term treatment of callus with 2-deoxyglucose had only minor effects on the carbohydrate status of each line, whereas long-term phosphate deficiency caused an increase in starch and a decrease in soluble sugar content in both transgenic and control lines. There were no consistent differences between the three callus lines in metabolism of [U-14C]glucose in response to incubation with 2-deoxyglucose. In contrast, there was a decrease in partitioning of label into glycolytic products (particularly organic acids) in untransformed callus during growth on phosphate-depleted medium. This decrease was greatly attenuated in the transgenic lines with increased fructose 2,6-bisphosphate content. This suggests that the conversion of hexose phosphates to triose phosphates is constrained under phosphate-deficient conditions, and that this restriction can be relieved by activation of pyrophosphate:fructose-6-phosphate 1-phosphotransferase. However, since the transgenic and control lines did not differ in the extent to which the

  16. Comparison of friction stir welding heat transfer analysis methods and parametric study on unspecified input variables

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Wook; Jang, Beom Seon [Seoul National University, Seoul (Korea, Republic of)

    2014-10-15

    A three-dimensional numerical model was constructed to analyze the heat transfer of friction stir welding using Fluent and ANSYS multi-physics. The analysis result was used to calculate welding deformation and residual stress. Before the numerical simulation, several simplifying assumptions were applied to the model. Three different methods of heat transfer analysis were employed, and several assumptions were applied to each heat source model. In this work, several parametric studies were performed for certain unspecified variables. The calculated temperature data were compared with experimental data from relevant studies. Additionally, the advantages and disadvantages of the three heat transfer analysis methods were compared.

  17. Study of the influence of solar variability on a regional (Indian) climate: 1901-2007

    CERN Document Server

    Aslam, O P M

    2014-01-01

    We use Indian temperature data of more than 100 years to study the influence of solar activity on climate. We study the Sun-climate relationship by averaging solar and climate data at various time scales; decadal, solar activity and solar magnetic cycles. We also consider the minimum and maximum values of sunspot number (SSN) during each solar cycle. This parameter SSN is correlated better with Indian temperature when these data are averaged over solar magnetic polarity epochs (SSN maximum to maximum). Our results indicate that the solar variability may still be contributing to ongoing climate change and suggest for more investigations.

  18. Ignoring the matching variables in cohort studies - when is it valid and why?

    Science.gov (United States)

    Sjölander, Arvid; Greenland, Sander

    2013-11-30

    In observational studies of the effect of an exposure on an outcome, the exposure-outcome association is usually confounded by other causes of the outcome (potential confounders). One common method to increase efficiency is to match the study on potential confounders. Matched case-control studies are relatively common and well covered by the literature. Matched cohort studies are less common but do sometimes occur. It is often argued that it is valid to ignore the matching variables, in the analysis of matched cohort data. In this paper, we provide analyses delineating the scope and limits of this argument. We discuss why the argument does not carry over to effect estimation in matched case-control studies, although it does carry over to null-hypothesis testing. We also show how the argument does not extend to matched cohort studies when one adjusts for additional confounders in the analysis. Ignoring the matching variables can sometimes reduce variance, even though this is not guaranteed. We investigate the trade-off between bias and variance in deciding whether adjustment for matching factors is advisable. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Anatomy of the AGN in NGC 5548. VII. Swift study of obscuration and broadband continuum variability

    Science.gov (United States)

    Mehdipour, M.; Kaastra, J. S.; Kriss, G. A.; Cappi, M.; Petrucci, P.-O.; De Marco, B.; Ponti, G.; Steenbrugge, K. C.; Behar, E.; Bianchi, S.; Branduardi-Raymont, G.; Costantini, E.; Ebrero, J.; Di Gesu, L.; Matt, G.; Paltani, S.; Peterson, B. M.; Ursini, F.; Whewell, M.

    2016-04-01

    We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670 ks of observing time. Both broadband spectral modelling and temporal rms variability analysis are applied to the Swift data. We disentangle the variability caused by absorption, due to an obscuring weakly-ionised outflow near the disk, from variability of the intrinsic continuum components (the soft X-ray excess and the power law) originating in the disk and its associated coronae. The spectral model that we apply to this extensive Swift data is the global model that we derived for NGC 5548 from analysis of the stacked spectra from our multi-satellite campaign of 2013 (including XMM-Newton, NuSTAR, and HST). The results of our Swift study show that changes in the covering fraction of the obscurer is the primary and dominant cause of variability in the soft X-ray band on timescales of 10 days to ~5 months. The obscuring covering fraction of the X-ray source is found to range between 0.7 and nearly 1.0. The contribution of the soft excess component to the X-ray variability is often much less than that of the obscurer, but it becomes comparable when the optical-UV continuum flares up. We find that the soft excess is consistent with being the high-energy tail of the optical-UV continuum and can be explained by warm Comptonisation: up-scattering of the disk seed photons in a warm, optically thick corona as part of the inner disk. To this date, the Swift monitoring of NGC 5548 shows that the obscurer has been continuously present in our line of sight for at least 4 years (since at least February 2012).

  20. A Study about Problem Solving Skill Variable in Terms of Some Variables of Footballers Who Play Football Professionally

    Science.gov (United States)

    Akpinar, Selahattin

    2012-01-01

    The aim of this study is to present the problem solving skill levels of sportsmen who play football professionally, and to determine whether problem solving skill levels differ according to sportsmen's, sports club, age, marital status, parents' educational status, father's occupation, occupation in the game, year of playing football…

  1. A Study about Problem Solving Skill Variable in Terms of Some Variables of Footballers Who Play Football Professionally

    Science.gov (United States)

    Akpinar, Selahattin

    2012-01-01

    The aim of this study is to present the problem solving skill levels of sportsmen who play football professionally, and to determine whether problem solving skill levels differ according to sportsmen's, sports club, age, marital status, parents' educational status, father's occupation, occupation in the game, year of playing football…

  2. Three-dimensional study of turbulent flow characteristics of an offset plane jet with variable density

    Science.gov (United States)

    Assoudi, Ali; Habli, Sabra; Mahjoub Saïd, Nejla; Bournot, Hervé; Le Palec, Georges

    2016-11-01

    An experimental and numerical investigation of the flow field of variable density turbulent offset jet is presented. The velocity measurements are performed using a Velocimetry Laser Doppler technique for an offset height h. Three cases of variable-density turbulent plane jets discharging from a rectangular nozzle into a quiescent medium are studied. The variation density jets considered were revealed at different Reynolds numbers. In the second step of this work, a numerical three-dimensional model of the problem is simulated through the resolution of the Navier-Stokes equations by means of the finite volume method and the Reynolds stress model second-order turbulent closure model. A non-uniform mesh system tightened close to the emitting nozzle and both the vertical and horizontal walls is also adopted. A good level of agreement was achieved, between the experiments and the calculations. Once the model validated, our model allowed the evaluation of the influence of the variation density on the characterizing features of the resulting flow filed. It is found that the centerline velocity and concentration of the heavier jet decays much faster than in the two other jets, and a similar behavior for the vertical profiles in the three variable-density jets is well reproduced in the simulation.

  3. The impact of climate variability on the production of Black Sea anchovy: a modeling study

    Science.gov (United States)

    Guraslan, Ceren; Fach, Bettina A.; Oguz, Temel I.; Salihoglu, Baris

    2010-05-01

    The influence of climate variability on anchovy eggs and larvae production and the interaction with gelatineous zooplankton in the Black Sea is studied with a one-dimensional, lower trophic level and anchovy bioenergetics model including parameterizations for a gelatineous predator. Stochastic climate variability in the form of fifty-year interannual temperature and nutrient entrainment rate variability is used to simulate how climate-mediated effects cascade across trophic levels and how the anchovy population production responds to such disturbances. Model results reveal a high correlation of egg production and recruitment success in response to changes in temperature and nutrient entrainment rates and complex and highly nonlinear interactions between anchovy and gelatineous populations. Moreover, it is indicated in the results that temperature variation has strong long-term effects on anchovy population production and its signal propagates through successive adult year classes. Although, temperature has a direct effect on anchovy egg and larvae production via influencing mortality rates, it indirectly influences anchovy production by modulating the mixed layer depth, which affects phytoplankton blooms and zooplankton availability, the major food source of anchovy.

  4. Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study

    Energy Technology Data Exchange (ETDEWEB)

    Cappers, Peter; Mills, Andrew; Goldman, Charles; Wiser, Ryan; Eto, Joseph H.

    2011-09-10

    This scoping study focuses on the policy issues inherent in the claims made by some Smart Grid proponents that the demand response potential of mass market customers which is enabled by widespread implementation of Advanced Metering Infrastructure (AMI) through the Smart Grid could be the “silver bullet” for mitigating variable generation integration issues. In terms of approach, we will: identify key issues associated with integrating large amounts of variable generation into the bulk power system; identify demand response opportunities made more readily available to mass market customers through widespread deployment of AMI systems and how they can affect the bulk power system; assess the extent to which these mass market Demand Response (DR) opportunities can mitigate Variable Generation (VG) integration issues in the near-term and what electricity market structures and regulatory practices could be changed to further expand the ability for DR to mitigate VG integration issues over the long term; and provide a qualitative comparison of DR and other approaches to mitigate VG integration issues.

  5. On the use of structure functions to study blazar variability: caveats and problems

    CERN Document Server

    Emmanoulopoulos, Dimitrios; Uttley, Phil

    2010-01-01

    The extensive use of the structure function (SF) in the field of blazar variability suggests that characteristics time-scales are embedded in the light curves of these objects. We argue that for blazar variability studies, the SF results are sometimes erroneously interpreted leading to misconceptions about the actual source properties. Based on extensive simulations we caution that spurious breaks will appear in the SFs of almost all light curves, even though these light curves may contain no intrinsic characteristic time-scales. i.e. having a featureless underlying power-spectral-density (PSD). We show that the time-scales of the spurious SF-breaks depend mainly on the length of the artificial data set and also on the character of the variability i.e. the shape of the PSD. The SF is often invoked in the framework of shot-noise models to determine the temporal properties of individual shots. We caution that although the SF may be fitted to infer the shot parameters, the resultant shot-noise model is usually i...

  6. A naturalistic study of the effect of acupuncture on heart-rate variability.

    Science.gov (United States)

    Fasmer, Ole Bernt; Liao, Hanbo; Huang, Yong; Berle, Jan Øystein; Wu, Junxian; Oedegaard, Ketil Joachim; Wik, Gustav; Zhang, Zhangjin

    2012-02-01

    To study the effect of acupuncture on heart rate variability (HRV) by using linear and non-linear methods of analysis. 40 patients were recruited consecutively, including patients with insomnia, stomachache, diarrhea, dizziness, cervical syndrome, lower back pain, gonarthritis, peripheral facial paralysis, post-traumatic organic brain syndrome and urinary retention. Different acupoint prescriptions were used, according to the textbook for 5-years' education on traditional Chinese medicine specialty, which is used in Chinese Universities. HRV was recorded before, during, and after acupuncture. Acupuncture substantially reduced variability, causing a 41% reduction in the standard deviation. Using a Fourier analysis, the variances both in the low frequency (LF) and the high frequency (HF) ranges were markedly reduced, but the LF/HF ratio (an indication of sympatho-vagal balance) was not altered. The HR was unchanged. The sample entropy, which is a measure of the complexity of time series, was significantly increased (+35%). Acupuncture produced a pattern of changes different from that seen in pathological conditions, where increased variability and reduced complexity is expected. Copyright © 2012. Published by Elsevier B.V.

  7. Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009

    Science.gov (United States)

    Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Buson, S.; Carosi, A.; Chatterjee, A.; Clavero, R.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Godinović, N.; González Muñoz, A.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hanabata, Y.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Nogués, L.; Overkemping, A.; Paiano, S.; Palacio, J.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Saito, T.; Satalecka, K.; Schröder, S.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Steinbring, T.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Torres, D. F.; Toyama, T.; Treves, A.; Vanzo, G.; Verguilov, V.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Zanin, R.; Abeysekara, A. U.; Archambault, S.; Archer, A.; Benbow, W.; Bird, R.; Buchovecky, M.; Buckley, J. H.; Bugaev, V.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Flinders, A.; Fortson, L.; Gillanders, G. H.; Griffin, S.; Grube, J.; Hütten, M.; Hanna, D.; Holder, J.; Humensky, T. B.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Krennrich, F.; Lang, M. J.; Maier, G.; McCann, A.; Moriarty, P.; Mukherjee, R.; Nieto, D.; O'Brien, S.; Ong, R. A.; Otte, N.; Park, N.; Perkins, J.; Pichel, A.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rovero, A. C.; Rulten, C.; Sadeh, I.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Wakely, S. P.; Weinstein, A.; Wilcox, P.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; Razzaque, S.; Villata, M.; Raiteri, C. M.; Aller, H. D.; Aller, M. F.; Larionov, V. M.; Arkharov, A. A.; Blinov, D. A.; Efimova, N. V.; Grishina, T. S.; Hagen-Thorn, V. A.; Kopatskaya, E. N.; Larionova, L. V.; Larionova, E. G.; Morozova, D. A.; Troitsky, I. S.; Ligustri, R.; Calcidese, P.; Berdyugin, A.; Kurtanidze, O. M.; Nikolashvili, M. G.; Kimeridze, G. N.; Sigua, L. A.; Kurtanidze, S. O.; Chigladze, R. A.; Chen, W. P.; Koptelova, E.; Sakamoto, T.; Sadun, A. C.; Moody, J. W.; Pace, C.; Pearson, R.; Yatsu, Y.; Mori, Y.; Carraminyana, A.; Carrasco, L.; de la Fuente, E.; Norris, J. P.; Smith, P. S.; Wehrle, A.; Gurwell, M. A.; Zook, A.; Pagani, C.; Perri, M.; Capalbi, M.; Cesarini, A.; Krimm, H. A.; Kovalev, Y. Y.; Kovalev, Yu. A.; Ros, E.; Pushkarev, A. B.; Lister, M. L.; Sokolovsky, K. V.; Kadler, M.; Piner, G.; Lähteenmäki, A.; Tornikoski, M.; Angelakis, E.; Krichbaum, T. P.; Nestoras, I.; Fuhrmann, L.; Zensus, J. A.; Cassaro, P.; Orlati, A.; Maccaferri, G.; Leto, P.; Giroletti, M.; Richards, J. L.; Max-Moerbeck, W.; Readhead, A. C. S.

    2017-07-01

    Context. We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the γ-ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV tohard X-rays; and GASP-WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the γ-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Aims: The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the "single-curve SSC model adjustment" typically reported in the literature. Methods: We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing

  8. Lift Optimization Study of a Multi-Element Three-Segment Variable Camber Airfoil

    Science.gov (United States)

    Kaul, Upender K.; Nguyen, Nhan T.

    2016-01-01

    This paper reports a detailed computational high-lift study of the Variable Camber Continuous Trailing Edge Flap (VCCTEF) system carried out to explore the best VCCTEF designs, in conjunction with a leading edge flap called the Variable Camber Krueger (VCK), for take-off and landing. For this purpose, a three-segment variable camber airfoil employed as a performance adaptive aeroelastic wing shaping control effector for a NASA Generic Transport Model (GTM) in landing and take-off configurations is considered. The objective of the study is to define optimal high-lift VCCTEF settings and VCK settings/configurations. A total of 224 combinations of VCK settings/configurations and VCCTEF settings are considered for the inboard GTM wing, where the VCCTEFs are configured as a Fowler flap that forms a slot between the VCCTEF and the main wing. For the VCK settings of deflection angles of 55deg, 60deg and 65deg, 18, 19 and 19 vck configurations, respectively, were considered for each of the 4 different VCCTEF deflection settings. Different vck configurations were defined by varying the horizontal and vertical distance of the vck from the main wing. A computational investigation using a Reynolds-Averaged Navier-Stokes (RANS) solver was carried out to complement a wind-tunnel experimental study covering three of these configurations with the goal of identifying the most optimal high-lift configurations. Four most optimal high-lift configurations, corresponding to each of the VCK deflection settings, have been identified out of all the different configurations considered in this study yielding the highest lift performance.

  9. Studying the photometric and spectroscopic variability of the magnetic hot supergiant ζ Orionis Aa

    Science.gov (United States)

    Buysschaert, B.; Neiner, C.; Richardson, N. D.; Ramiaramanantsoa, T.; David-Uraz, A.; Pablo, H.; Oksala, M. E.; Moffat, A. F. J.; Mennickent, R. E.; Legeza, S.; Aerts, C.; Kuschnig, R.; Whittaker, G. N.; Popowicz, A.; Handler, G.; Wade, G. A.; Weiss, W. W.

    2017-06-01

    Massive stars play a significant role in the chemical and dynamical evolution of galaxies. However, much of their variability, particularly during their evolved supergiant stage, is poorly understood. To understand the variability of evolved massive stars in more detail, we present a study of the O9.2Ib supergiant ζ Ori Aa, the only currently confirmed supergiant to host a magnetic field. We have obtained two-color space-based BRIght Target Explorer photometry (BRITE) for ζ Ori Aa during two observing campaigns, as well as simultaneous ground-based, high-resolution optical CHIRON spectroscopy. We perform a detailed frequency analysis to detect and characterize the star's periodic variability. We detect two significant, independent frequencies, their higher harmonics, and combination frequencies: the stellar rotation period Prot = 6.82 ± 0.18 d, most likely related to the presence of the stable magnetic poles, and a variation with a period of 10.0 ± 0.3 d attributed to circumstellar environment, also detected in the Hα and several He I lines, yet absent in the purely photospheric lines. We confirm the variability with Prot/4, likely caused by surface inhomogeneities, being the possible photospheric drivers of the discrete absorption components. No stellar pulsations were detected in the data. The level of circumstellar activity clearlydiffers between the two BRITE observing campaigns. We demonstrate that ζ Ori Aa is a highly variable star with both periodic and non-periodic variations, as well as episodic events. The rotation period we determined agrees well with the spectropolarimetric value from the literature. The changing activity level observed with BRITE could explain why the rotational modulation of the magnetic measurements was not clearly detected at all epochs. Based on data collected by the BRITE Constellation satellite mission, designed, built, launched, operated and supported by the Austrian Research Promotion Agency (FFG), the University of

  10. Oscar: a portable prototype system for the study of climate variability

    Science.gov (United States)

    Madonna, Fabio; Rosoldi, Marco; Amato, Francesco

    2015-04-01

    The study of the techniques for the exploitation of solar energy implies the knowledge of nature, ecosystem, biological factors and local climate. Clouds, fog, water vapor, and the presence of large concentrations of dust can significantly affect the way to exploit the solar energy. Therefore, a quantitative characterization of the impact of climate variability at the regional scale is needed to increase the efficiency and sustainability of the energy system. OSCAR (Observation System for Climate Application at Regional scale) project, funded in the frame of the PO FESR 2007-2013, aims at the design of a portable prototype system for the study of correlations among the trends of several Essential Climate Variables (ECVs) and the change in the amount of solar irradiance at the ground level. The final goal of this project is to provide a user-friendly low cost solution for the quantification of the impact of regional climate variability on the efficiency of solar cell and concentrators to improve the exploitation of natural sources. The prototype has been designed on the basis of historical measurements performed at CNR-IMAA Atmospheric Observatory (CIAO). Measurements from satellite and data from models have been also considered as ancillary to the study, above all, to fill in the gaps of existing datasets. In this work, the results outcome from the project activities will be presented. The results include: the design and implementation of the prototype system; the development of a methodology for the estimation of the impact of climate variability, mainly due to aerosol, cloud and water vapor, on the solar irradiance using the integration of the observations potentially provided by prototype; the study of correlation between the surface radiation, precipitation and aerosols transport. In particular, a statistical study will be presented to assess the impact of the atmosphere on the solar irradiance at the ground, quantifying the contribution due to aerosol and

  11. Selection of key ambient particulate variables for epidemiological studies - applying cluster and heatmap analyses as tools for data reduction.

    Science.gov (United States)

    Gu, Jianwei; Pitz, Mike; Breitner, Susanne; Birmili, Wolfram; von Klot, Stephanie; Schneider, Alexandra; Soentgen, Jens; Reller, Armin; Peters, Annette; Cyrys, Josef

    2012-10-01

    The success of epidemiological studies depends on the use of appropriate exposure variables. The purpose of this study is to extract a relatively small selection of variables characterizing ambient particulate matter from a large measurement data set. The original data set comprised a total of 96 particulate matter variables that have been continuously measured since 2004 at an urban background aerosol monitoring site in the city of Augsburg, Germany. Many of the original variables were derived from measured particle size distribution (PSD) across the particle diameter range 3 nm to 10 μm, including size-segregated particle number concentration, particle length concentration, particle surface concentration and particle mass concentration. The data set was complemented by integral aerosol variables. These variables were measured by independent instruments, including black carbon, sulfate, particle active surface concentration and particle length concentration. It is obvious that such a large number of measured variables cannot be used in health effect analyses simultaneously. The aim of this study is a pre-screening and a selection of the key variables that will be used as input in forthcoming epidemiological studies. In this study, we present two methods of parameter selection and apply them to data from a two-year period from 2007 to 2008. We used the agglomerative hierarchical cluster method to find groups of similar variables. In total, we selected 15 key variables from 9 clusters which are recommended for epidemiological analyses. We also applied a two-dimensional visualization technique called "heatmap" analysis to the Spearman correlation matrix. 12 key variables were selected using this method. Moreover, the positive matrix factorization (PMF) method was applied to the PSD data to characterize the possible particle sources. Correlations between the variables and PMF factors were used to interpret the meaning of the cluster and the heatmap analyses

  12. The futile cycling of hexose phosphates could account for the fact that hexokinase exerts a high control on glucose phosphorylation but not on glycolytic rate in transgenic potato (Solanum tuberosum) roots.

    Science.gov (United States)

    Claeyssen, Eric; Dorion, Sonia; Clendenning, Audrey; He, Jiang Zhou; Wally, Owen; Chen, Jingkui; Auslender, Evgenia L; Moisan, Marie-Claude; Jolicoeur, Mario; Rivoal, Jean

    2013-01-01

    The metabolism of potato (Solanum tuberosum) roots constitutively over- and underexpressing hexokinase (HK, EC 2.7.1.1) was examined. An 11-fold variation in HK activity resulted in altered root growth, with antisense roots growing better than sense roots. Quantification of sugars, organic acids and amino acids in transgenic roots demonstrated that the manipulation of HK activity had very little effect on the intracellular pools of these metabolites. However, adenylate and free Pi levels were negatively affected by an increase in HK activity. The flux control coefficient of HK over the phosphorylation of glucose was measured for the first time in plants. Its value varied with HK level. It reached 1.71 at or below normal HK activity value and was much lower (0.32) at very high HK levels. Measurements of glycolytic flux and O(2) uptake rates demonstrated that the differences in glucose phosphorylation did not affect significantly glycolytic and respiratory metabolism. We hypothesized that these results could be explained by the existence of a futile cycle between the pools of hexose-Ps and carbohydrates. This view is supported by several lines of evidence. Firstly, activities of enzymes capable of catalyzing these reactions were detected in roots, including a hexose-P phosphatase. Secondly, metabolic tracer experiments using (14)C-glucose as precursor showed the formation of (14)C-fructose and (14)C-sucrose. We conclude that futile cycling of hexose-P could be partially responsible for the differences in energetic status in roots with high and low HK activity and possibly cause the observed alterations in growth in transgenic roots. The involvement of HK and futile cycles in the control of glucose-6P metabolism is discussed.

  13. The futile cycling of hexose phosphates could account for the fact that hexokinase exerts a high control on glucose phosphorylation but not on glycolytic rate in transgenic potato (Solanum tuberosum roots.

    Directory of Open Access Journals (Sweden)

    Eric Claeyssen

    Full Text Available The metabolism of potato (Solanum tuberosum roots constitutively over- and underexpressing hexokinase (HK, EC 2.7.1.1 was examined. An 11-fold variation in HK activity resulted in altered root growth, with antisense roots growing better than sense roots. Quantification of sugars, organic acids and amino acids in transgenic roots demonstrated that the manipulation of HK activity had very little effect on the intracellular pools of these metabolites. However, adenylate and free Pi levels were negatively affected by an increase in HK activity. The flux control coefficient of HK over the phosphorylation of glucose was measured for the first time in plants. Its value varied with HK level. It reached 1.71 at or below normal HK activity value and was much lower (0.32 at very high HK levels. Measurements of glycolytic flux and O(2 uptake rates demonstrated that the differences in glucose phosphorylation did not affect significantly glycolytic and respiratory metabolism. We hypothesized that these results could be explained by the existence of a futile cycle between the pools of hexose-Ps and carbohydrates. This view is supported by several lines of evidence. Firstly, activities of enzymes capable of catalyzing these reactions were detected in roots, including a hexose-P phosphatase. Secondly, metabolic tracer experiments using (14C-glucose as precursor showed the formation of (14C-fructose and (14C-sucrose. We conclude that futile cycling of hexose-P could be partially responsible for the differences in energetic status in roots with high and low HK activity and possibly cause the observed alterations in growth in transgenic roots. The involvement of HK and futile cycles in the control of glucose-6P metabolism is discussed.

  14. The Futile Cycling of Hexose Phosphates Could Account for the Fact That Hexokinase Exerts a High Control on Glucose Phosphorylation but Not on Glycolytic Rate in Transgenic Potato (Solanum tuberosum) Roots

    Science.gov (United States)

    Clendenning, Audrey; He, Jiang Zhou; Wally, Owen; Chen, Jingkui; Auslender, Evgenia L.; Moisan, Marie-Claude; Jolicoeur, Mario; Rivoal, Jean

    2013-01-01

    The metabolism of potato (Solanum tuberosum) roots constitutively over- and underexpressing hexokinase (HK, EC 2.7.1.1) was examined. An 11-fold variation in HK activity resulted in altered root growth, with antisense roots growing better than sense roots. Quantification of sugars, organic acids and amino acids in transgenic roots demonstrated that the manipulation of HK activity had very little effect on the intracellular pools of these metabolites. However, adenylate and free Pi levels were negatively affected by an increase in HK activity. The flux control coefficient of HK over the phosphorylation of glucose was measured for the first time in plants. Its value varied with HK level. It reached 1.71 at or below normal HK activity value and was much lower (0.32) at very high HK levels. Measurements of glycolytic flux and O2 uptake rates demonstrated that the differences in glucose phosphorylation did not affect significantly glycolytic and respiratory metabolism. We hypothesized that these results could be explained by the existence of a futile cycle between the pools of hexose-Ps and carbohydrates. This view is supported by several lines of evidence. Firstly, activities of enzymes capable of catalyzing these reactions were detected in roots, including a hexose-P phosphatase. Secondly, metabolic tracer experiments using 14C-glucose as precursor showed the formation of 14C-fructose and 14C-sucrose. We conclude that futile cycling of hexose-P could be partially responsible for the differences in energetic status in roots with high and low HK activity and possibly cause the observed alterations in growth in transgenic roots. The involvement of HK and futile cycles in the control of glucose-6P metabolism is discussed. PMID:23382859

  15. The Impacts of ALMA Primary Variables on Profitability An Empirical Study of Indonesian Banking

    Directory of Open Access Journals (Sweden)

    Sapto Jumono

    2015-04-01

    Full Text Available This study aims to determine the impact of liquidity on BEP and ROE in Indonesian banking industry. The supporting theory in this study is ALMA theory. Based on annual data for the period 2001-2014 and following purposive sampling technique, the acquired amount of sample study is 97 banks. The data is analyzed using panel data regression of GMM Arrelano Bond, as a novelty in data processing, therefore the speed of adjustment can be known. The ALMA variables such as LAR, capital, leverage, operating expenses, interest income, and CAR sensitivity have a significant effect on BEP and ROE. Meanwhile LDR, NPL, the FBI have no impact on profitability. The implication of this study is the fact that banking performance in Indonesia can be leveled up through the reduction in mortgage interest rates and increment of credit volume and FBI.

  16. SPEED COMPLIANCE IN FREEWAY VARIABLE SPEED LIMIT SYSTEM – CASE STUDY OF THE PRAGUE CITY RING

    Directory of Open Access Journals (Sweden)

    Michał MATOWICKI

    2016-03-01

    Full Text Available Many previous studies have confirmed the strong relationship between speed compliance and the frequency and severity of traffic accidents. Variable speed limit (VSL system as a measure to improve traffic safety enables the freeway system to change its posted speed limit based on various traffic and environmental conditions. Such system helps drivers to recognize the upcoming events, to adjust their driving style and in such way to address speed variation of the traffic flow. This is called speed harmonization. Although many studies researching the effect of VSL system on the traffic stream can be found, there are only few addressing its influence on the drivers behavior, particularly focusing on their tolerance limit and compliance, which has crucial meaning for future design of controlling algorithms. This study was prepared to inspect this grey area by studying the data from the VSL system at Prague city ring, describing the influence of the highway management system and its influence on drivers.

  17. The study of micro crack detection in dissimilar metal weld using a variable ultrasound infrared thermography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Hak; Choi, Man Yong; Kwon, Koo Ahn [Dept. of Research and Development, Korea Research Institute of Smart Material and Structures System Association, Daejeon (Korea, Republic of); Park, Hee Sang [Center of Safety Measurements, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2015-06-15

    As a nondestructive inspection technology currently in use, infrared thermography has gradually expanded its application range to industry. The method detects only defect areas by grafting ultrasound on a technique of detecting infrared energy emitted from all objects with absolute temperature of 0 K and converting this energy into thermography for inspection. Ultrasound infrared thermography has merits including the ability to inspect a wide area in a short time without contacting the target object. This study investigated the applicability of the technique for defect detection using variable ultrasound excitation inspection methods on samples of Terfenol-D, a magnetostrictive material with a tunable natural resonant frequency.

  18. Chipping away at a mountain: Genomic studies in Common Variable Immunodeficiency

    Science.gov (United States)

    Keller, Michael D; Jyonouchi, Soma

    2012-01-01

    Common variable immunodeficiency (CVID) represents one of the most frequently diagnosed disorders of the immune system. Though several causative and associated genes have been identified, the origins of most cases remain unknown. Diagnostic delay is common due to the gradual evolution and wide spectrum of phenotypes, which can include autoimmune disease, enteropathy, and lung disease. A recent genome wide array identified novel gene associations with CVID, and also showed that identification of a genetic signature via a Support Vector Machine algorithm may be a powerful diagnostic tool. Studies utilizing whole genome or exome sequencing have also met with success in identifying new causes of CVID in subgroups of patients. PMID:23201919

  19. Comparative study on performances of a continuously variable transmission used in two different powertrain architectures

    Science.gov (United States)

    Sibiceanu, A. R.; Ivan, F.; Nicolae, V.; Iorga, A.; Cioroianu, C.

    2017-08-01

    Given the importance of reducing carbon emissions from road transport, price and security of oil supply, hybrid electric vehicle can provide a viable alternative solution to conventional vehicles, equipped with thermal engines, which use fossil fuels. Based on the growing trends of new vehicles sales, which include hybrid and electric vehicles closely associated with their use in terms of harmful emissions, strict regulations are established. In this paper were created models of thermal and hybrid electric powertrains groups, using computer simulation program AVL Cruise, making a comparative study using petroleum fuels for continuously variable transmission. The results obtained highlights both fuel consumption as well as pollutant emissions.

  20. High SST Variability South of Martha’s Vineyard: Observation and Modeling Study

    Science.gov (United States)

    2009-01-01

    Journal of Marine Systems 78 (2009) 59–76 Contents lists available at ScienceDirect Journal of Marine Systems j ourna l homepage: www.e lsev ie r.com/ locate / jmarsysHigh SST variability south of Martha’s Vineyard: Observation and modeling study Xiaodong Hong a,⁎, Paul J. Martin b, Shouping Wang a, Clark Rowley b a Naval Research Laboratory, Monterey, CA 93943, USA b Naval Research Laboratory, Stennis Space Center, MS 39529-5004, USA⁎ Corresponding author. 7 Grace Hopper Avenue, Mon 831

  1. Analytical study on coordinative optimization of convection in tubes with variable heat flux

    Institute of Scientific and Technical Information of China (English)

    YUAN Zhongxian; ZHANG Jianguo; JIANG Mingjian

    2004-01-01

    The laminar heat transfer in the thermal entrance region in round tubes, which has a variable surface heat flux boundary condition, is analytically studied. The results show that the heat transfer coefficient is closely related to the wall temperature gradient along the tube axis. The greater the gradient, the higher the heat transfer rate. Furthermore, the coordination of the velocity and the temperature gradient fields is also analysed under different surface heat fluxes. The validity of the field coordination principle is verified by checking the correlation of heat transfer coefficient and the coordination degree. The results also demonstrate that optimizing the thermal boundary condition is a way to enhance heat transfer.

  2. [Explore objective clinical variables for detecting delirium in ICU patients: a prospective case-control study].

    Science.gov (United States)

    Liu, Xiaojiang; Lyu, Jie; An, Youzhong

    2017-04-01

    The aim of this case-control study is to explore clinical objective variables for diagnosing delirium of intensive care unit (ICU) patients. According to the method of prospective case-control study, critical adult postoperative patients who were transferred to ICU of Peking University People's Hospital from October 2015 to May 2016 and needed mechanical ventilation were included. After evaluating the Richmond agitation sedation scale score (RASS), the patients whose score were -2 or greater were sorted into two groups, delirium and non-delirium, according to the confusion assessment method for the ICU (CAM-ICU). Then these patients were observed by domestic multifunctional detector for electroencephalographic (EEG) variables such as brain lateralization, brain introvert, brain activity, brain energy consumption, focus inward, focus outward, cerebral inhibition, fatigue, sleep severity, sedation index, pain index, anxiety index, fidgety index, stress index and the cerebral blood flow (CBF) index which was named of perfusion index. Other variables including indexes of ICU blood gas analysis, which was consisted of variables of blood gas analysis, routine blood test and biochemistry, previous history and prognostic outcome was recorded. Binary logistic regression was used for multivariate analysis. Forty-three postoperative patients, who needed intensive care, were included. Eighteen were in delirium group and twenty-five in control group. Excluding the trauma, variables like gender, age, temperature, heart rate, respiratory rate, mean arterial pressure, acute physiology and chronic health evaluationII(APACHEII) score, organ failure, dementia and emergency surgery didn't show any statistical significance between two groups. The trauma in delirious patients increased obviously compared with the control group (33.3% vs. 4.0%, P = 0.031). Except for the brain activity [122.47 (88.62, 154.21) vs. 89.40 (86.27, 115.97), P = 0.034], there were no statistical differences in

  3. Study of the interrelationships among chemical and petrographic variables of United States coals

    Energy Technology Data Exchange (ETDEWEB)

    Waddell, C.; Davis, A.; Spackman, W.; Griffiths, J. C.

    1978-03-01

    Multivariate statistical techniques are used in a study of the interrelationships among various coal properties. The properties chosen for study are the components of the ultimate analysis (carbon, hydrogen, organic sulfur, nitrogen and oxygen); moisture; volatile matter; calorific value; maximum reflectance of the vitrinite-group macerals; and the relative proportions of the vitrinite-, liptinite-, and inertinite-group macerals. The coals included in the study are from four coal provinces (Eastern, Interior, Rocky Mountain, and Northern Great Plains) and range in rank from lignite to anthracite. A coal's characteristics, properties, and utilization behavior are determined by the maceral and mineral materials composing the coal. The level of coalification achieved by the maceral materials is of critical importance in fixing the properties. A factor analysis performed on all data together indicates that most variation in the data set is correlated with changes in rank (variables which vary with rank include carbon, oxygen, calorific value, moisture, volatile matter, and reflectance). The maceral groups account for the next greatest amount of variation. Nitrogen and sulfur are each independent of all other variables. A cluster analysis indicates that the data set represents a continuum with no distinct groups; however, the data set may be dissected into four groups distinguished from each other on the basis of rank, on the relative proportions of the maceral groups, and on the organic sulfur content. Factor analyses of the individual groups provide insights into coalification at various stages of rank.

  4. Prefrontal Hemodynamics in Toddlers at Rest: A Pilot Study of Developmental Variability

    Directory of Open Access Journals (Sweden)

    Afrouz A. Anderson

    2017-05-01

    Full Text Available Functional near infrared spectroscopy (fNIRS is a non-invasive functional neuroimaging modality. Although, it is amenable to use in infants and young children, there is a lack of fNIRS research within the toddler age range. In this study, we used fNIRS to measure cerebral hemodynamics in the prefrontal cortex (PFC in 18–36 months old toddlers (n = 29 as part of a longitudinal study that enrolled typically-developing toddlers as well as those “at risk” for language and other delays based on presence of early language delays. In these toddlers, we explored two hemodynamic response indices during periods of rest during which time audiovisual children's programming was presented. First, we investigate Lateralization Index, based on differences in oxy-hemoglobin saturation from left and right prefrontal cortex. Then, we measure oxygenation variability (OV index, based on variability in oxygen saturation at frequencies attributed to cerebral autoregulation. Preliminary findings show that lower cognitive (including language abilities are associated with fNIRS measures of both lower OV index and more extreme Lateralization index values. These preliminary findings show the feasibility of using fNIRS in toddlers, including those at risk for developmental delay, and lay the groundwork for future studies.

  5. A Study of Bite Force and Various Variables in Children Segregated by Angle's Classification

    Science.gov (United States)

    Sandhu, Navreet; Kashyap, Rita

    2012-01-01

    ABSTRACT The stomatographic system has been studied by several researchers, yet it is still unclear, weather a genetically determined facial morphology decides the strength of masticatory muscles,1 or weather a strong musculature influences the form of the face. This formed the basis of present study to relate muscle activity with various malocclusions. Thus, 60 samples of younger age group were divided according to Angle classification and maximum bite force was recorded among the groups. Newly designed bite force recorder was used for recording bite force at molar and at incisal region. Influence of various independent variables like gender, overjet and overbite of the subjects on the bite force was also checked. It was concluded that maximum bite force at intercuspal position (molar) and anterior bite position (incisal) were not significantly different between normal, class I, class II div 1 and class III malocclusion groups. There was no significant correlation between incisal bite force and overjet or overbite, but there was a highly significant difference (p < 0.001) between the males and females for maximum bite force at intercuspal position, with males biting harder than the females. How to cite this article: Singh S, Sandhu N, Kashyap R. A Study of Bite Force and Various Variables in Children Segregated by Angle's Classification. Int J Clin Pediatr Dent 2012;5(2):118-123. PMID:25206150

  6. A standardized approach to study human variability in isometric thermogenesis during low-intensity physical activity

    Directory of Open Access Journals (Sweden)

    Delphine eSarafian

    2013-07-01

    Full Text Available Limitations of current methods: The assessment of human variability in various compartments of daily energy expenditure (EE under standardized conditions is well defined at rest (as basal metabolic rate and thermic effect of feeding, and currently under validation for assessing the energy cost of low-intensity dynamic work. However, because physical activities of daily life consist of a combination of both dynamic and isometric work, there is also a need to develop standardized tests for assessing human variability in the energy cost of low-intensity isometric work.Experimental objectives: Development of an approach to study human variability in isometric thermogenesis by incorporating a protocol of intermittent leg press exercise of varying low-intensity isometric loads with measurements of EE by indirect calorimetry. Results: EE was measured in the seated position with the subject at rest or while intermittently pressing both legs against a press-platform at 5 low-intensity isometric loads (+5, +10, + 15, +20 and +25 kg force, each consisting of a succession of 8 cycles of press (30 s and rest (30 s. EE, integrated over each 8-min period of the intermittent leg press exercise, was found to increase linearly across the 5 isometric loads with a correlation coefficient (r > 0.9 for each individual. The slope of this EE-Load relationship, which provides the energy cost of this standardized isometric exercise expressed per kg force applied intermittently (30 s in every min, was found to show good repeatability when assessed in subjects who repeated the same experimental protocol on 3 separate days: its low intra-individual coefficient of variation (CV of ~ 10% contrasted with its much higher inter-individual CV of 35%; the latter being mass-independent but partly explained by height. Conclusion: This standardized approach to study isometric thermogenesis opens up a new avenue for research in EE phenotyping and metabolic predisposition to obesity

  7. Quantification of Inter-Tsunami Model Variability for Hazard Assessment Studies

    Science.gov (United States)

    Catalan, P. A.; Alcantar, A.; Cortés, P. I.

    2014-12-01

    There is a wide range of numerical models capable of modeling tsunamis, most of which have been properly validated and verified against standard benchmark cases and particular field or laboratory cases studies. Consequently, these models are regularly used as essential tools in estimating the tsunami hazard on coastal communities by scientists, or consulting companies, and treating model results in a deterministic way. Most of these models are derived from the same set of equations, typically the Non Linear Shallow Water Equations, to which ad-hoc terms are added to include physical effects such as friction, the Coriolis force, and others. However, not very often these models are used in unison to address the variability in the results. Therefore, in this contribution, we perform a high number of simulations using a set of numerical models and quantify the variability in the results. In order to reduce the influence of input data on the results, a single tsunami scenario is used over a common bathymetry. Next, we perform model comparisons as to asses sensitivity to changes in grid resolution and Manning roughness coefficients. Results are presented either as intra-model comparisons (sensitivity to changes using the same model) and inter-model comparisons (sensitivity to changing models). For the case tested, it was observed that most models reproduced fairly consistently the arrival and periodicity of the tsunami waves. However, variations in amplitude, characterized by the standard-deviation between model runs, could be as large as the mean signal. This level of variability is considered too large for deterministic assessment, reinforcing the idea that uncertainty needs to be included in such studies.

  8. How to include the variability of TMS responses in simulations: a speech mapping case study

    Science.gov (United States)

    De Geeter, N.; Lioumis, P.; Laakso, A.; Crevecoeur, G.; Dupré, L.

    2016-11-01

    When delivered over a specific cortical site, TMS can temporarily disrupt the ongoing process in that area. This allows mapping of speech-related areas for preoperative evaluation purposes. We numerically explore the observed variability of TMS responses during a speech mapping experiment performed with a neuronavigation system. We selected four cases with very small perturbations in coil position and orientation. In one case (E) a naming error occurred, while in the other cases (NEA, B, C) the subject appointed the images as smoothly as without TMS. A realistic anisotropic head model was constructed of the subject from T1-weighted and diffusion-weighted MRI. The induced electric field distributions were computed, associated to the coil parameters retrieved from the neuronavigation system. Finally, the membrane potentials along relevant white matter fibre tracts, extracted from DTI-based tractography, were computed using a compartmental cable equation. While only minor differences could be noticed between the induced electric field distributions of the four cases, computing the corresponding membrane potentials revealed different subsets of tracts were activated. A single tract was activated for all coil positions. Another tract was only triggered for case E. NEA induced action potentials in 13 tracts, while NEB stimulated 11 tracts and NEC one. The calculated results are certainly sensitive to the coil specifications, demonstrating the observed variability in this study. However, even though a tract connecting Broca’s with Wernicke’s area is only triggered for the error case, further research is needed on other study cases and on refining the neural model with synapses and network connections. Case- and subject-specific modelling that includes both electromagnetic fields and neuronal activity enables demonstration of the variability in TMS experiments and can capture the interaction with complex neural networks.

  9. Reporting of sex as a variable in cardiovascular studies using cultured cells

    Directory of Open Access Journals (Sweden)

    Taylor K

    2011-11-01

    Full Text Available Abstract Background Chromosomal complement, including that provided by the sex chromosomes, influences expression of proteins and molecular signaling in every cell. However, less than 50% of the scientific studies published in 2009 using experimental animals reported sex as a biological variable. Because every cell has a sex, we conducted a literature review to determine the extent to which sex is reported as a variable in cardiovascular studies on cultured cells. Methods Articles from 10 cardiovascular journals with high impact factors (Circulation, J Am Coll Cardiol, Eur Heart J, Circ Res, Arterioscler Thromb Vasc Biol, Cardiovasc Res, J Mol Cell Cardiol, Am J Physiol Heart Circ Physiol, J Heart Lung Transplant and J Cardiovasc Pharmacol and published in 2010 were searched using terms 'cultured' and 'cells' in any order to determine if the sex of those cells was reported. Studies using established cell lines were excluded. Results Using two separate search strategies, we found that only 25 of 90 articles (28% and 20 of 101 articles (19.8% reported the sex of cells. Of those reporting the sex of cells, most (68.9%; n = 31 used only male cells and none used exclusively female cells. In studies reporting the sex of cells of cardiovascular origin, 40% used vascular smooth-muscle cells, and 30% used stem/progenitor cells. In studies using cells of human origin, 35% did not report the sex of those cells. None of the studies using neonatal cardiac myocytes reported the sex of those cells. Conclusions The complement of sex chromosomes in cells studied in culture has the potential to affect expression of proteins and 'mechanistic' signaling pathways. Therefore, consistent with scientific excellence, editorial policies should require reporting sex of cells used in in vitro experiments.

  10. A study of process variables for the photocatalytic degradation of rhodamine B

    Directory of Open Access Journals (Sweden)

    E. T. Soares

    2007-03-01

    Full Text Available The photoactivated degradation reaction of rhodamine B (RB was studied using P-25 TiO2 (Degussa as catalyst. Three process variables - temperature, initial pH, and catalyst concentration - were evaluated. Temperature had a slight effect on reaction rate; however, the combined effect of pH and catalyst concentration was greater. pH affected the catalyst particle's adsorption of RB, altering the reaction rate. The concentration of the catalyst was significant only up to 0,65 g L-1. The effect of temperature was studied at optimum pH and 50ºC was found to be the optimum operational temperature. The effect of the presence of a surfactant (sodium dodecylsulfate, SDS and ionic contaminants (Cl- and SO4- in the reaction system was also studied. The surfactant improved the catalyst's adsorption of RB by more than 80%, increasing the degradation reaction rate as well. The ionic contaminants reduced the reaction rate.

  11. Stemflow Variability in Tropical Lowland Forest Landscape Transformation System: Case Study at Jambi Province, Indonesia

    Directory of Open Access Journals (Sweden)

    Bejo Slamet

    2015-06-01

    Full Text Available Land cover change may cause change on the hydrological function of an area, particularly on the distribution of rainfall that reach land surface. This study describes the characteristic of stemflow occurred within 4 ecosystems in Jambi, namely logged forest, jungle rubber, rubber plantation, and oil palm plantation. The main objective of the study was to measure the variability of stemflow in those 4 ecosystems. The main data used were rainfall and stemflow data that were directly measured for 5 months. The derived regression equation model showed that stemflow increase with rainfall depth. It was shown that values of stemflow amongs plantation types was varied indicated by the difference of its regression coefficients, as well as variations of the rainfall at the same transformation type. The percentage of stemflow to rainfall was ranging from 0.04–0.21% for rubber, 0.10–0.38% for jungle rubber, 0.28–0.54% for forest, and 0.84–3.07% for oil palm. The oil palm provided the highest stemflow volume compared to other land cover type. The uniqueness of oil palm canopy may cause the drainage of water from the canopy to the main stem that indicated by highest stemflow funneling ratio value. Rainfall significantly affected the amount of stemflow compared with the characteristics of the plant. Keywords: forest transformation, land cover change, stemflow variability, stemflow funnelling ratio

  12. Studying interactions between climate variability and vegetation dynamic using a phenology based approach

    Science.gov (United States)

    Horion, S.; Cornet, Y.; Erpicum, M.; Tychon, B.

    2013-02-01

    In this paper we investigated if and how a signature of climate control on vegetation growth can be individualized at regional scale using time series of SPOT-VEGETATION NDVI and ECMWF meteorological data. Twelve regions characterized by dominant and stable cropland or grassland covers were selected in Europe and Africa. Our results show that the relationship between NDVI and meteorological parameters is highly complex and significantly vary trough the phenological cycle of the plants. Hence, interactions between vegetation dynamics and climate variability must be studied at a smaller time scale in order to identify properly the limiting factors to vegetation growth. Using NDVI metrics, vegetative phases (from green-up to maximum NDVI) and reproductive phases (from maximum NDVI to maturity) were identified for each region. Cross-correlation analysis revealed that, in most of the cases, the best scores of Pearson's r are obtained when we considered the vegetative phase (from green-up to maximum of NDVI) and the reproductive phase (from maximum of NDVI to maturity) separately. We also showed that climatic constraints identified using yearly proxies of climate and vegetation do not depict correctly or completely the climate control on vegetation development. In that sense the complexity of the climate-vegetation relationship, which is spatially and temporally variable, is well underlined in this study.

  13. Study on Yang-Xu Using Body Constitution Questionnaire and Blood Variables in Healthy Volunteers

    Directory of Open Access Journals (Sweden)

    Hong-Jhang Chen

    2016-01-01

    Full Text Available Traditional Chinese medicine (TCM formulates treatment according to body constitution (BC differentiation. Different constitutions have specific metabolic characteristics and different susceptibility to certain diseases. This study aimed to assess the Yang-Xu constitution using a body constitution questionnaire (BCQ and clinical blood variables. A BCQ was employed to assess the clinical manifestation of Yang-Xu. The logistic regression model was conducted to explore the relationship between BC scores and biomarkers. Leave-one-out cross-validation (LOOCV and K-fold cross-validation were performed to evaluate the accuracy of a predictive model in practice. Decision trees (DTs were conducted to determine the possible relationships between blood biomarkers and BC scores. According to the BCQ analysis, 49% participants without any BC were classified as healthy subjects. Among them, 130 samples were selected for further analysis and divided into two groups. One group comprised healthy subjects without any BC (68%, while subjects of the other group, named as the sub-healthy group, had three BCs (32%. Six biomarkers, CRE, TSH, HB, MONO, RBC, and LH, were found to have the greatest impact on BCQ outcomes in Yang-Xu subjects. This study indicated significant biochemical differences in Yang-Xu subjects, which may provide a connection between blood variables and the Yang-Xu BC.

  14. Family Accommodation in Obsessive-Compulsive Disorder: A Study on Associated Variables

    Directory of Open Access Journals (Sweden)

    Teresa Cosentino

    2015-10-01

    Full Text Available The present study aimed to examine family accommodation in relatives of obsessive-compulsive disease (OCD patients. Accommodation was assessed in a sample of 31 relatives of OCD patients by means of the Family Accommodation Scale. Other variables measured as predictors of accommodation were the tendency of a family member to feel guilty, sensitivity to guilt, anxiety sensitivity and the prevalence of a passive communication style. Accommodation was found to be rather widespread in the family members who took part in our study, and they tended to show more accommodation the greater their sensitivity to guilt and the stable tendency to experience this emotion as well as anxiety sensitivity and a passive communication style. Multiple linear regression analyses showed that, among the variables considered, the family member’s sensitivity to guilt is the only factor which can predict accommodation with regard to the patient’s demands for involvement. On the other hand, the small number of family members in the sample and the lack of clinical data on patients (such as the severity, typology and duration of their obsessive-compulsive disorder pose limits to the generalizability of the results and point to the need for further research.

  15. A longitudinal study of blood pressure variability in African-American and European American youth

    NARCIS (Netherlands)

    Li, Zhibin; Snieder, Harold; Su, Shaoyong; Harshfield, Gregory A.; Treiber, Frank A.; Wang, Xiaoling

    Objectives High blood pressure variability is increasingly used as a predictor of target-organ damage and cardiovascular events. However, little is known about blood pressure variability changes with age and its possible sociodemographic, anthropometric, and genetic moderators. Methods

  16. Statistically Optimal Approximations of Astronomical Signals: Implications to Classification and Advanced Study of Variable Stars

    Science.gov (United States)

    Andronov, I. L.; Chinarova, L. L.; Kudashkina, L. S.; Marsakova, V. I.; Tkachenko, M. G.

    2016-06-01

    We have elaborated a set of new algorithms and programs for advanced time series analysis of (generally) multi-component multi-channel observations with irregularly spaced times of observations, which is a common case for large photometric surveys. Previous self-review on these methods for periodogram, scalegram, wavelet, autocorrelation analysis as well as on "running" or "sub-interval" local approximations were self-reviewed in (2003ASPC..292..391A). For an approximation of the phase light curves of nearly-periodic pulsating stars, we use a Trigonometric Polynomial (TP) fit of the statistically optimal degree and initial period improvement using differential corrections (1994OAP.....7...49A). For the determination of parameters of "characteristic points" (minima, maxima, crossings of some constant value etc.) we use a set of methods self-reviewed in 2005ASPC..335...37A, Results of the analysis of the catalogs compiled using these programs are presented in 2014AASP....4....3A. For more complicated signals, we use "phenomenological approximations" with "special shapes" based on functions defined on sub-intervals rather on the complete interval. E. g. for the Algol-type stars we developed the NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv1212.6707A, 2015JASS...32..127A), which was compared to common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree. The method allows determine the minimal set of parameters required for the "General Catalogue of Variable Stars", as well as an extended set of phenomenological and astrophysical parameters which may be used for the classification. Totally more that 1900 variable stars were studied in our group using these methods in a frame of the "Inter-Longitude Astronomy" campaign (2010OAP....23....8A) and the "Ukrainian Virtual Observatory" project (2012KPCB...28...85V).

  17. Variable selection for propensity score models when estimating treatment effects on multiple outcomes: a simulation study.

    Science.gov (United States)

    Wyss, Richard; Girman, Cynthia J; LoCasale, Robert J; Brookhart, Alan M; Stürmer, Til

    2013-01-01

    It is often preferable to simplify the estimation of treatment effects on multiple outcomes by using a single propensity score (PS) model. Variable selection in PS models impacts the efficiency and validity of treatment effects. However, the impact of different variable selection strategies on the estimated treatment effects in settings involving multiple outcomes is not well understood. The authors use simulations to evaluate the impact of different variable selection strategies on the bias and precision of effect estimates to provide insight into the performance of various PS models in settings with multiple outcomes. Simulated studies consisted of dichotomous treatment, two Poisson outcomes, and eight standard-normal covariates. Covariates were selected for the PS models based on their effects on treatment, a specific outcome, or both outcomes. The PSs were implemented using stratification, matching, and weighting (inverse probability treatment weighting). PS models including only covariates affecting a specific outcome (outcome-specific models) resulted in the most efficient effect estimates. The PS model that only included covariates affecting either outcome (generic-outcome model) performed best among the models that simultaneously controlled measured confounding for both outcomes. Similar patterns were observed over the range of parameter values assessed and all PS implementation methods. A single, generic-outcome model performed well compared with separate outcome-specific models in most scenarios considered. The results emphasize the benefit of using prior knowledge to identify covariates that affect the outcome when constructing PS models and support the potential to use a single, generic-outcome PS model when multiple outcomes are being examined. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Brain Morphometric Correlates of Metabolic Variables in HIV: The CHARTER Study

    Science.gov (United States)

    ARCHIBALD, S.L.; MCCUTCHAN, J.A.; SANDERS, C.; WOLFSON, T.; JERNIGAN, T.L.; ELLIS, R.J.; ANCES, B.M.; COLLIER, A.C.; MCARTHUR, J.C.; MORGELLO, S.; SIMPSON, D.M.; MARRA, C.; GELMAN, B.B.; CLIFFORD, D.B.; GRANT, I.; FENNEMA-NOTESTINE, C.

    2014-01-01

    Objectives: Obesity and other metabolic variables are associated with abnormal brain structural volumes and cognitive dysfunction in HIV-uninfected populations. Since individuals with HIV infection on combined antiretroviral therapy (CART) often have systemic metabolic abnormalities and changes in brain morphology and function, we examined associations among brain volumes and metabolic factors in the multi-site CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) cohort. Design: Cross-sectional study of 222 HIV-infected individuals. Methods: Metabolic variables included body mass index (BMI), total blood cholesterol (C), low- and high-density lipoprotein C (LDL-C and HDL-C), blood pressure, random blood glucose, and diabetes. MRI measured volumes of cerebral white matter, abnormal white matter, cortical and subcortical gray matter, and ventricular and sulcal CSF. Multiple linear regression models allowed us to examine metabolic variables separately and in combination to predict each regional volume. Results: Greater body mass index (BMI) was associated with smaller cortical gray and larger white matter volumes. Higher total cholesterol (C) levels were associated with smaller cortex volumes; higher LDL-C was associated with larger cerebral white matter volumes, while higher HDL-C levels were associated with larger sulci. Higher blood glucose levels and diabetes were associated with more abnormal white matter. Conclusions: Multiple atherogenic metabolic factors contribute to regional brain volumes in HIV-infected, CART-treated patients, reflecting associations similar to those found in HIV-uninfected individuals. These risk factors may accelerate cerebral atherosclerosis and consequent brain alterations and cognitive dysfunction. PMID:25227933

  19. Study of process variables in industrial acetic fermentation by a continuous pilot fermentor and response surfaces.

    Science.gov (United States)

    Garrido-Vidal, Diego; Pizarro, Consuelo; González-Sáiz, José M

    2003-01-01

    The modeling and optimization of industrial processes requires an intensive study of the factors involved. In this work, a continuous pilot system for studying the industrial process of acetic fermentation is developed. A Doehlert design is applied to the five variables involved in the pilot process. This experimental design allows reduction of the experimental burden and the maximum amount of information to be obtained, studying the factors at different levels depending on their significance. The experimental system provides a robust measure of the specific growth rate and the rates of substrates consumption and acetic acid production, related to the flow of effluent stream evaluated in the steady state. The results demonstrate the growth-associated kinetics of substrates and product, and the yield factors are calculated with low values of variances for the coefficients, i.e., within the range 1-11%. The specific growth rate suits the quadratic model proposed. The response surfaces generated by the model are applied to explain the behavior of the bacterial growth and, therefore, the effects of the process variables studied over the acetic acid production. Very low levels of ethanol or oxygen make the acetification rate decrease, and a saturation effect with high levels of ethanol or oxygen is also deduced. The effects of the aeration rate, agitation, and overpressure suggest a kind of inhibition of the acetic acid production caused by the oxygen that has not been practically studied before. The temperature strengthens the inhibitory effect of the ethanol and the oxygen. The conclusions of this work consolidate the structure of a hybrid model for the acetic fermentation.

  20. The Importance of Flexibility of Pronunciation in Learning to Decode: A Training Study in Set for Variability

    Science.gov (United States)

    Zipke, Marcy

    2016-01-01

    The ability to flexibly approach the pronunciation of unknown words, or set "for variability", has been shown to contribute to word recognition skills. However, this is the first study that has attempted to teach students strategies for increasing their set for variability. Beginning readers (N = 15) were instructed to correct oral…

  1. Feasibility and design study of continuously variable capacity refrigeration plant. A demonstration at Safeway plc

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    This report concerns a feasibility and design study carried out on a new type of high efficiency refrigeration system for use in supermarkets. The study compared the performance of Margaux Continuously Variable Capacity (CVC) refrigeration equipment with conventional supermarket plant. The tests were carried out at a Presto store in Stanley near Newcastle-upon-Tyne from August 1988 to February 1989. They involved assessment of systems for both chilled food (HT) and frozen food (LT). Significant energy savings were achieved by the CVC equipment. The HT system reduced energy consumption by 56% compared with conventional plant. Measured LT savings were only 13%, although adjustments made for monitoring problems and improved temperature control indicate savings of around 30%. (author)

  2. Analysis on Variables Affecting the Creation of Tourist Destination Image: Case Study on Domestic Tourists Visiting

    Directory of Open Access Journals (Sweden)

    Khairani

    2010-06-01

    Full Text Available The purpose of this study is to examine the variables that affect the image creation of tourism destinations. This research is a case study on domestic tourists visiting Yogyakarta from 2007 to 2009. This research uses an exploratory and descriptive design, conducted once in one period (cross-sectional. A number of 105 domestic tourists were selected as samples by means of non-probability sampling method and snowball sampling technique. The data were analyzed using reliability and validity tests, frequency distributions, and regression analyses. Results showed that overall image was significantly constructed and affected by cognitive and affective evaluations. Cognitive evaluation was significantly affected by the types of information source from books and movies, while affective evaluation was affected significantly by social-psychological motivations. The research also proves that Yogyakarta has fulfilled the requirements to become a tourist destination; respondents showed positive feelings towards the town and also perceived the town positively.

  3. Spatially variable risk factors for malaria in a geographically heterogeneous landscape, western Kenya: an explorative study.

    Science.gov (United States)

    Homan, Tobias; Maire, Nicolas; Hiscox, Alexandra; Di Pasquale, Aurelio; Kiche, Ibrahim; Onoka, Kelvin; Mweresa, Collins; Mukabana, Wolfgang R; Ross, Amanda; Smith, Thomas A; Takken, Willem

    2016-01-04

    Large reductions in malaria transmission and mortality have been achieved over the last decade, and this has mainly been attributed to the scale-up of long-lasting insecticidal bed nets and indoor residual spraying with insecticides. Despite these gains considerable residual, spatially heterogeneous, transmission remains. To reduce transmission in these foci, researchers need to consider the local demographical, environmental and social context, and design an appropriate set of interventions. Exploring spatially variable risk factors for malaria can give insight into which human and environmental characteristics play important roles in sustaining malaria transmission. On Rusinga Island, western Kenya, malaria infection was tested by rapid diagnostic tests during two cross-sectional surveys conducted 3 months apart in 3632 individuals from 790 households. For all households demographic data were collected by means of questionnaires. Environmental variables were derived using Quickbird satellite images. Analyses were performed on 81 project clusters constructed by a traveling salesman algorithm, each containing 50-51 households. A standard linear regression model was fitted containing multiple variables to determine how much of the spatial variation in malaria prevalence could be explained by the demographic and environmental data. Subsequently, a geographically-weighted regression (GWR) was performed assuming non-stationarity of risk factors. Special attention was taken to investigate the effect of residual spatial autocorrelation and local multicollinearity. Combining the data from both surveys, overall malaria prevalence was 24%. Scan statistics revealed two clusters which had significantly elevated numbers of malaria cases compared to the background prevalence across the rest of the study area. A multivariable linear model including environmental and household factors revealed that higher socioeconomic status, outdoor occupation and population density were

  4. Variability in vulnerability assessment of older people by individual general practitioners: a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Yvonne M Drewes

    Full Text Available BACKGROUND: In clinical practice, GPs appeared to have an internalized concept of "vulnerability." This study investigates the variability between general practitioners (GPs in their vulnerability-assessment of older persons. METHODS: Seventy-seven GPs categorized their 75-plus patients (n = 11392 into non-vulnerable, possibly vulnerable, and vulnerable patients. GPs personal and practice characteristics were collected. From a sample of 2828 patients the following domains were recorded: sociodemographic, functional [instrumental activities in daily living (IADL, basic activities in daily living (BADL], somatic (number of diseases, polypharmacy, psychological (Mini-Mental State Examination, 15-item Geriatric Depression Scale; GDS-15 and social (De Jong-Gierveld Loneliness Scale; DJG. Variability in GPs' assessment of vulnerability was tested with mixed effects logistic regression. P-values for variability (pvar were calculated by the log-likelihood ratio test. RESULTS: Participating GPs assessed the vulnerability of 10,361 patients. The median percentage of vulnerable patients was 32.0% (IQR 19.5 to 40.1%. From the somatic and psychological domains, GPs uniformly took into account the patient characteristics 'total number of diseases' (OR 1.7, 90% range  = 0, p var = 1, 'polypharmacy' (OR 2.3, 90% range  = 0, p var = 1 and 'GDS-15' (OR 1.6, 90% range  = 0, p var = 1. GPs vary in the way they assessed their patients' vulnerability in the functional domain (IADL: median OR 2.8, 90% range 1.6, p var < 0.001, BADL: median OR 2.4, 90% range 2.9, p var < 0.001 and the social domain (DJG: median OR 1.2, 90% range  = 1.2, p var < 0.001. CONCLUSIONS: GPs seem to share a medical concept of vulnerability, since they take somatic and psychological characteristics uniformly into account in the vulnerability-assessment of older persons. In the functional and social domains, however, variability was found. Vulnerability assessment by GPs might be a

  5. Thermal front propagation in variable aperture fracture-matrix system: A numerical study

    Indian Academy of Sciences (India)

    Nikhil Bagalkot; G Suresh Kumar

    2015-04-01

    A numerical study on the effect of complex fracture aperture geometry on propagation of thermal front in a coupled single fracture-matrix system has been carried out. Sinusoidal and logarithmic functions have been used to capture the variation in fracture aperture. Modifications have been made to existing coupled partial differential governing equations to consider the variation of fracture aperture. Effect of temperature on the thermal and physical properties of rock have been incorporated. A fully implicit finite difference scheme has been used to discretize the coupled governing equations. Thermal convection, dispersion and conduction are the major transport processes within fracture, while conduction is the major transport process within rock matrix. The results suggest that variation of fracture aperture increases the heat transfer rate at the fracture-matrix interface. Sensitivity analysis on rock thermal conductivity and fracture aperture have been carried out. The results suggest that the heat transfer from rock matrix to fracture for the case of the parallel plate model is greatly dependent on the rock thermal conductivity (m) as compared to variable aperture model. Further, the thermal front propagation for both parallel plate model and variable aperture model is sensitive to changes in fracture aperture. The heat transfer rate at the interface is greater at smaller fracture apertures and decreases with increase in aperture.

  6. Preliminary experimental results on studying possibility of variable mass liner (VML) formation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The main objective of the present experiment was to study the formation process and initial stage of acceleration of a variable-mass plasma liner (VML). The method is based on magnetic acceleration of a liner with the mass reduced during such acceleration. The experiment was carried out on February 16 at VNIIEF. This report describes the results of measurements obtained in the experiment and preliminary analysis of the results characterizing operation of the test facility main units: helical EMG; 5-module disk EMG 400 mm in diameter (DEMG); ponderomotive unit (PU) with a cylindric condensed liner and a special tooth-cutoff. The first part of the report presents measurement results obtained on the VNIIEF`s diagnostic equipment that are compared with those obtained by American specialists on their diagnostic equipment. Information submitted by American specialists is included in part 2 of this report. The second part of the report presents preliminary computational-theoretic analysis of the main measured results describing operation of DEMG TL system in the experiment; experimental data are compared with theoretical ones obtained before and after the experiment. But more emphasis is placed on the data preliminary analysis indicating that in the experiment a variable mass liner is formed (VML or plasma bubble).

  7. Interhousehold variability and its effects on seed circulation networks: a case study from northern Cameroon

    Directory of Open Access Journals (Sweden)

    Jean Wencélius

    2016-03-01

    Full Text Available We present a detailed ethnographic case study of sorghum seed acquisitions in a smallholder farming society in northern Cameroon. The effects of variability in household demographics and socioeconomic status on observed patterns of seed provisioning are explored alongside other variables such as age and gender. Our data set comprised 223 seed acquisition events. Independence tests (Pearson's chi-square and Fisher's exact tests were carried out to test for significant dependencies between individual- or household-level characteristics and properties of seed acquisition events (categories of seed source, social relationship of exchange, and type of landrace. Results indicate that wealth is a structuring factor of the local seed circulation network in as much as it is highly correlated with household composition and size. Members from wealthy households benefit from a more diverse set of seed sources. Their greater number of coresidents and the importance of intrahousehold dynamics of seed transactions also play a role in making wealthy farmers more seed secure than others. The methodological implications of our findings indicate that when documenting seed exchange networks, the collection of data through a single informant or the undertaking of social network analyses at the household level may induce important biases.

  8. Loss of genetic variability induced by Agroecosystems: Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) as a case study.

    Science.gov (United States)

    Morales, A C; Lavagnini, T C; Freitas, S

    2013-02-01

    Four species of green lacewings occur in Brazil, of which Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) exhibits the widest geographical distribution. Chrysoperla externa is a predatory insect that is potentially useful as a biological control agent of agricultural pests. Studies on the genetic diversity of lacewing populations are essential to reduce the environmental and economic harm that may be caused by organisms with a low ability to adapt to the adverse and/or different environmental conditions to which they are exposed. We used the cytochrome oxidase I mitochondrial gene as a molecular marker to investigate the genetic diversity of green lacewing species collected from native and agroecosystem environments. Populations derived from native areas showed higher rates of genetic variability compared to populations from agroecosystems. Demographic changes in the form of population expansion were observed in agroecosystems, whereas populations in the native environment appeared stable over time. A statistical analysis showed significant genetic structure between each of the sampled groups, combined with its complete absence within each group, corroborating each group's identity. We infer that the loss of variability exhibited by populations from the agroecosystems is the result of genetic drift by means of the founder effect, a similar effect that has been observed in other introduced populations. Agroecosystems might therefore function as exotic areas for green lacewings, even when these areas are within the normal range of the species.

  9. Extensive X-ray variability studies of NGC 7314 using long XMM-Newton observations

    CERN Document Server

    Emmanoulopoulos, D; Vaughan, S; Papadakis, I E

    2016-01-01

    We present a detailed X-ray variability study of the low mass Active Galactic Nuclei (AGN) NGC 7314 using the two newly obtained XMM-Newton observations ($140$ and $130$ ks), together with two archival data sets of shorter duration ($45$ and $84$ ks). The relationship between the X-ray variability characteristics and other physical source properties (such as the black hole mass) are still relatively poorly defined, especially for low-mass AGN. We perform a new, fully analytical, power spectral density (PSD) model analysis method, which will be described in detail in a forthcoming paper, that takes into consideration the spectral distortions, caused by red-noise leak. We find that the PSD in the $0.5-10$ keV energy range, can be represented by a bending power-law with a bend around $6.7\\times10^{-5}$ Hz, having a slope of $0.51$ and $1.99$ below and above the bend, respectively. Adding our bend time-scale estimate, to an already published ensemble of estimates from several AGN, supports the idea that the bend ...

  10. Variability in drug use among newborns admitted to NICUs: a proposal for a European multicentre study

    Directory of Open Access Journals (Sweden)

    Laura Cuzzolin

    2014-01-01

    Full Text Available The use of drugs in newborns admitted to NICUs is characterized by a great variability. This widespread phenomenon, observed both within and between different countries, has been highlighted by reporting data on the treatment of neonatal sepsis and PDA throughout Europe: the dosages and the intervals between administrations of ciprofloxacin and fluconazole varied significantly and a wide variation was also observed as regards the use of NSAIDs to treat PDA. Given the unique characteristics of the neonatal population, the use of drugs on an individual basis could be sometimes justified. However, other factors such as the lack of evidence-based guidelines and the common use of drugs in an off-label manner (more than 80% of newborns receive this kind of treatment could contribute to the variability in medicine use, making the neonatal population vulnerable to adverse drug reactions (ADRs and medication errors: the potential ADRs rate, 3 times higher in pediatric wards, is more significantly higher in NICUs and the frequency of medication errors (mostly dose errors widely exceeds the medium value. The differences in clinical practices observed between NICUs need to be addressed at a European level and a multicentre study could be useful to harmonize drug use in newborns.

  11. Within-subject variability during spatial working memory in children with ADHD: an event-related potentials study.

    Science.gov (United States)

    Myatchin, I; Lemiere, J; Danckaerts, M; Lagae, L

    2012-04-01

    Working memory (WM) dysfunction and increased within-subject variability are known issues in attention deficit/hyperactivity disorder (ADHD) patients. Little is known about the electrophysiological characteristics of this variability. We evaluated behavioral and electrophysiological within-subject variability taking developmental aspects into account in a group of ADHD patients. Multichannel (n = 31) event-related potentials (ERP) were measured during a visuo-spatial backmatching task; 44 children (8-16 years old) were tested: 22 children with ADHD, combined (n = 17) and inattentive (n = 5) type, and 22 age- and intelligence-matched control children. One-backmatching (BM1) and two-backmatching (BM2) tasks were performed. Classical behavioral parameters and target and nontarget ERP were compared between groups. In addition, motor response variability and ERP amplitude variability were studied. Age-related changes in both motor response and ERP amplitude variability were analyzed in each group. Attention deficit/hyperactivity disorder children made more commission errors, which was more pronounced in the difficult (BM2) task. No difference between groups was found in ERP amplitude and in motor response variability. However, ADHD patients had higher ERP amplitude variability, which was again more pronounced in the difficult WM task. A delayed maturation of amplitude variability was seen in ADHD patients with a slower than in controls decrease in variability with age. This amplitude variability was correlated with the number of commissions, but in an opposite way for ADHD and control children. Our findings indicate an impaired visuo-spatial WM processing in ADHD children with greater ERP amplitude variability compared to controls. Our results also support the view of a delayed cortical development of visuo-spatial WM circuits in this disorder.

  12. Variability in baseline laboratory measurements of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

    Science.gov (United States)

    Ladwig, R; Vigo, A; Fedeli, L M G; Chambless, L E; Bensenor, I; Schmidt, M I; Vidigal, P G; Castilhos, C D; Duncan, B B

    2016-08-01

    Multi-center epidemiological studies must ascertain that their measurements are accurate and reliable. For laboratory measurements, reliability can be assessed through investigation of reproducibility of measurements in the same individual. In this paper, we present results from the quality control analysis of the baseline laboratory measurements from the ELSA-Brasil study. The study enrolled 15,105 civil servants at 6 research centers in 3 regions of Brazil between 2008-2010, with multiple biochemical analytes being measured at a central laboratory. Quality control was ascertained through standard laboratory evaluation of intra- and inter-assay variability and test-retest analysis in a subset of randomly chosen participants. An additional sample of urine or blood was collected from these participants, and these samples were handled in the same manner as the original ones, locally and at the central laboratory. Reliability was assessed with the intraclass correlation coefficient (ICC), estimated through a random effects model. Coefficients of variation (CV) and Bland-Altman plots were additionally used to assess measurement variability. Laboratory intra and inter-assay CVs varied from 0.86% to 7.77%. From test-retest analyses, the ICCs were high for the majority of the analytes. Notably lower ICCs were observed for serum sodium (ICC=0.50; 95%CI=0.31-0.65) and serum potassium (ICC=0.73; 95%CI=0.60-0.83), due to the small biological range of these analytes. The CVs ranged from 1 to 14%. The Bland-Altman plots confirmed these results. The quality control analyses showed that the collection, processing and measurement protocols utilized in the ELSA-Brasil produced reliable biochemical measurements.

  13. Variability of Data in High Throughput Experimentation for Catalyst Studies in Fuel Processing

    Directory of Open Access Journals (Sweden)

    Niels T.J. Luchters

    2017-04-01

    Full Text Available The use of high throughout and combinatorial experimentation is becoming commonplace in catalytic research. The benefits of parallel experiments are not only limited to reducing the time-to-market, but also give an opportunity to study processes in more depth, by generating more data. To investigate the complete parameter space, multiple experiments must be performed and the variability between these experiments must be quantifiable. In this project, the reproducibility and variance in high throughput catalyst preparation and parallel testing were determined. High-performance equipment was used in a catalyst development program for fuel processing, the production of fuel cell-grade hydrogen from hydrocarbon fuels. Four studies, involving water-gas shift conversion and high-temperature steam methane reforming, were performed to determine the reproducibility of the workflow from automated catalyst preparation to parallel activity testing. Statistical analyses showed the standard deviation in catalytic activities as determined by conversion, to be less than 6% of the average value. Copyright © 2017 BCREC GROUP. All rights reserved Received: 23rd September 2016; Revised: 18th November 2016; Accepted: 22nd November 2016 How to Cite: Luchters, N.T.J., Fletcher, J.V., Roberts, S.J., Fletcher, J.C.Q. (2017. Variability of Data in High Throughput Experimentation for Catalyst Studies in Fuel Processing.  Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 106-112 (doi:10.9767/bcrec.12.1.708.106-112 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.708.106-112

  14. Void formation at silicon nitride/silicon interfaces studied by variable-energy positrons

    Energy Technology Data Exchange (ETDEWEB)

    Halec, A.; Schultz, P.J. [University of Western Ontario, London, ON (Canada). Dept. of Physics; Boudreau, M.; Boumerzoug, M.; Mascher, P. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics; McCaffrey, J.P.; Jackman, T.E. [National Research Council of Canada, Ottawa, ON (Canada)

    1994-12-31

    Variable-energy positrons (VEP) were used to study the depth distribution of defects in SiN {sub x}/Si structures fabricated using ditertiary butyl silane (CONSI 4000) as the silicon precursor in an electron cyclotron resonance plasma chemical vapour deposition system. Films were grown to thicknesses ranging from 500 to 3500 A at substrate temperatures between room temperature and 400{sup o}C and under various plasma conditions. The VEP results give evidence for differing concentrations of very large open-volume defects at several of the SiN {sub x}/Si interfaces, confirmed by transmission and scanning electron microscopy. Their presence was correlated with non-reactive organosilicon adsorption on the substrates prior to the thin film deposition. (author).

  15. VARIABILITY STUDIES IN M3 GENERATION IN BLACKGRAM (VIGNA MUNGO (L.HEPPER

    Directory of Open Access Journals (Sweden)

    M P MESHRAM

    2013-12-01

    Full Text Available In the present study, pure line seeds of black gram variety viz. T-9, TPU-4 and one promising genotype AKU-18 was treated with gamma irradiation (15kR, 25kR and 35kR with the objective to assess the variability in M3 generation.. Highest GCV and PCV and high estimates of heritability were recorded for the characters sprouting percentage, number of pods plant-1 and grain yield plant-1 (g. High heritability accompanied with high genetic advance was recorded for number of pods plant-1 governed by additive gene effects and therefore selection based on phenotypic performance will be useful to improve character in future.

  16. Mobile biofeedback of heart rate variability in patients with diabetic polyneuropathy: a preliminary study.

    Science.gov (United States)

    Druschky, Katrin; Druschky, Achim

    2015-09-01

    Biofeedback of heart rate variability (HRV) was applied to patients with diabetic polyneuropathy using a new mobile device allowing regularly scheduled self-measurements without the need of visits to a special autonomic laboratory. Prolonged generation of data over an eight-week period facilitated more precise investigation of cardiac autonomic function and assessment of positive and negative trends of HRV parameters over time. Statistical regression analyses revealed significant trends in 11 of 17 patients, while no significant differences were observed when comparing autonomic screening by short-term HRV and respiratory sinus arrhythmia at baseline and after the 8 weeks training period. Four patients showed positive trends of HRV parameters despite the expected progression of cardiac autonomic dysfunction over time. Patient compliance was above 50% in all but two patients. The results of this preliminary study indicate a good practicality of the handheld device and suggest a potential positive effect on cardiac autonomic neuropathy in patients with type 2 diabetes.

  17. Independent, additive effects of five dietary variables on ad libitum energy intake in a residential study.

    Science.gov (United States)

    Urban, Lorien E; McCrory, Megan A; Rasmussen, Helen; Greenberg, Andrew S; Fuss, Paul J; Saltzman, Edward; Roberts, Susan B

    2014-09-01

    To examine the relationship between dietary characteristics of self-selected foods and energy balance in a cafeteria-style dining hall. Ad libitum dietary intake from a self-selection menu was measured over two days in 151 adults (70% female, mean age 41 years, mean BMI 24.9 kg/m(2) ). The associations of dietary variables with energy balance (calculated as measured energy intake/predicted energy requirements, pER) were assessed. Measured energy intake was significantly correlated with pER (R(2) =0.83, P obese individuals. There are independent associations of dietary protein, liquid calories, energy density, dietary variety, and glycemic index with energy balance, indicating additive effects of these dietary factors on energy intake and energy balance. Intervention studies are needed to determine whether dietary prescriptions combining these dietary factors facilitate long-term prevention of weight gain. © 2014 The Obesity Society.

  18. EIT Micro-Variability Studies : Preliminary Results from the SOHO JOP 80 Campaign

    Science.gov (United States)

    Clette, F.; Berghmans, D.

    1999-09-01

    The first results from the high-cadence imaging campaign run in May 98, by several space-based instruments with ground support (SOHO JOP80), are presented. General properties and scaling laws are deduced for a fairly large sample of small-amplitude short-lived impulsive brightenings occuring locally in active region loops. From these, we derive some conclusions about similarities with soft-X ray microflares. Several classes of minor transients are distinguished, such as loop-like and twin brightenings. We find also evidence for propagating compressive waves in extended field lines rooted near one magnetic pole of the active region. This study provides a first inventory of small-scale variabilities in view of the full analysis of this huge and rich data set.

  19. Variable-charge method applied to study coupled grain boundary migration in the presence of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, A. [Paul Scherrer Institute, Villigen, PSI-Villigen CH-5232 (Switzerland); Politano, O. [Institut Carnot de Bourgogne, UMR 5209 CNRS-Universite de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon Cedex (France); Derlet, P.M. [Paul Scherrer Institute, Villigen, PSI-Villigen CH-5232 (Switzerland); Van Swygenhoven, H. [Paul Scherrer Institute, Villigen, PSI-Villigen CH-5232 (Switzerland)], E-mail: helena.vs@psi.ch

    2009-04-15

    One of the important differences between simulation and experiments in grain boundary (GB)-dominated metallic structures is the lack of impurities such as oxygen in computational samples. A modified variable-charge method [Elsener A, Politano O, Derlet PM, Van Swygenhoven H. Modell Simul Mater Sci Eng 2008;16:025006] based on the Streitz and Mintmire approach [Streitz FH, Mintmire JW. Phys Rev B 1994;50:11996] is used to study coupled GB motion in an Al bicrystal with a [1 1 2] symmetrical tilt GB in the presence of substitutional O, and compared with the stick-slip process identified by Cahn and Mishin [Cahn JW, Mishin Y, Suzuki A. Acta Mater 2006;54:4953]. It is found that the critical shear stress for migration of the GB increases linearly with the number of O atoms. These observations are then rationalized in terms of the internal stress signature of the O atoms in the vicinity of the boundary.

  20. Multi-wavelength Polarimetry and Variability Study of M87 Jet

    CERN Document Server

    Avachat, Sayali S; Sparks, William B; Cara, Mihai; Owen, Frazer N

    2014-01-01

    We present a high resolution polarimetry and variability study of the M87 jet using VLA and HST data taken during 2002 to 2008. Both data-sets have an angular resolution as high as 0.06$"$, which is 2-3 times better than previous observations. New morphological details are revealed in both the optical and radio, which can help to reveal the energetic and magnetic field structure of the jet. By comparing the data with previously published HST and VLA observations, we show that the jet$'$s morphology in total and polarized light is changing significantly on timescales of $\\sim$a decade. We compare the evolution of the inner jet (particularly the nucleus and knot HST-1), when our observations overlap with the multi-wavelength monitoring campaigns conducted with HST and Chandra. We use these data to comment on particle acceleration and main emission processes.

  1. Climate variability as a threat for countries progressing towards malaria elimination: The case study of Peru

    Science.gov (United States)

    Mousam, Aneela; Maggioni, Viviana; Quispe, Antonio; Aquila, Valentina

    2015-04-01

    Malaria cases reported by the Peruvian Ministry of Health demonstrate a 61% reduction of malaria in the last decade (2001- 2010). However, during the years 2011-14 malaria increased by ~2.7 folds in Peru and ~5 folds in Loreto, an Amazonian department that continues contributing over 90% of the malaria cases in Peru. Past studies have indicated that there is a strong association between climate variability and malaria rates. The purpose of this study is to test the hypothesis that climate variables have played a key role in the recent increase of malaria cases in Peru. Climate data, such as precipitation, temperature, humidity and surface pressure simulated by the NASA MERRA model during a 10-year ling time series (2004-2013) are used to verify this hypothesis. Preliminary data analyses show large deviations from the 10-year mean (i.e., climatological anomalies) in humidity, surface pressure, and temperature during 2010 up to four times larger than previous and subsequent years. An increase of 8% in precipitation yearly averages is observed in 2010, which also corresponds with the following reverse of the downward trend of malaria incidence, particularly in Loreto. The sudden amplification of climatological anomalies in 2010 could have set the environmental conditions that caused the re-emergence of malaria in 2011. Investigation is underway to link weekly malaria data from different districts in Peru to the climate conditions at those locations during the past ten years. This will be crucial in understanding why some countries, despite all necessary efforts, are unable to completely eliminate malaria.

  2. Variables Influencing the Depth of Conscious Sedation in Plastic Surgery: A Prospective Study

    Science.gov (United States)

    Kim, Wonwoo; Park, Hyochun; Kim, Hoonnam

    2017-01-01

    Background Conscious sedation has been widely utilized in plastic surgery. However, inadequate research has been published evaluating adequate drug dosage and depth of sedation. In clinical practice, sedation is often inadequate or accompanied by complications when sedatives are administered according to body weight alone. The purpose of this study was to identify variables influencing the depth of sedation during conscious sedation for plastic surgery. Methods This prospective study evaluated 97 patients who underwent plastic surgical procedures under conscious sedation. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and glucose levels were measured. Midazolam and ketamine were administered intravenously according to a preset protocol. Bispectral index (BIS) recordings were obtained to evaluate the depth of sedation 4, 10, 15, and 20 minutes after midazolam administration. Associations between variables and the BIS were assessed using multiple regression analysis. Results Alcohol intake and female sex were positively associated with the mean BIS (P<0.01). Age was negatively associated with the mean BIS (P<0.01). Body mass index (P=0.263), creatinine clearance (P=0.832), smoking history (P=0.398), glucose (P=0.718), AST (P=0.729), and ALT (P=0.423) were not associated with the BIS. Conclusions Older patients tended to have a greater depth of sedation, whereas females and patients with greater alcohol intake had a shallower depth of sedation. Thus, precise dose adjustments of sedatives, accounting for not only weight but also age, sex, and alcohol consumption, are required to achieve safe, effective, and predictable conscious sedation. PMID:28194341

  3. Study on phylogenetic relationships, variability, and correlated mutations in M2 proteins of influenza virus A.

    Directory of Open Access Journals (Sweden)

    Ly Le

    Full Text Available M2 channel, an influenza virus transmembrane protein, serves as an important target for antiviral drug design. There are still discordances concerning the role of some residues involved in proton transfer as well as the mechanism of inhibition by commercial drugs. The viral M2 proteins show high conservativity; about 3/4 of the positions are occupied by one residue in over 95%. Nine M2 proteins from the H3N2 strain and possibly two proteins from H2N2 strains make a phylogenic cluster closely related to 2RLF. The variability range is limited to 4 residues/position with one exception. The 2RLF protein stands out by the presence of 2 serines at the positions 19 and 50, which are in most other M2 proteins occupied by cysteines. The study of correlated mutations shows that there are several positions with significant mutational correlation that have not been described so far as functionally important. That there are 5 more residues potentially involved in the M2 mechanism of action. The original software used in this work (Consensus Constructor, SSSSg, Corm, Talana is freely accessible as stand-alone offline applications upon request to the authors. The other software used in this work is freely available online for noncommercial purposes at public services on bioinformatics such as ExPASy or NCBI. The study on mutational variability, evolutionary relationship, and correlated mutation presented in this paper is a potential way to explain more completely the role of significant factors in proton channel action and to clarify the inhibition mechanism by specific drugs.

  4. Causal inference in longitudinal comparative effectiveness studies with repeated measures of a continuous intermediate variable.

    Science.gov (United States)

    Wang, Chen-Pin; Jo, Booil; Brown, C Hendricks

    2014-09-10

    We propose a principal stratification approach to assess causal effects in nonrandomized longitudinal comparative effectiveness studies with a binary endpoint outcome and repeated measures of a continuous intermediate variable. Our method is an extension of the principal stratification approach originally proposed for the longitudinal randomized study "Prevention of Suicide in Primary Care Elderly: Collaborative Trial" to assess the treatment effect on the continuous Hamilton depression score adjusting for the heterogeneity of repeatedly measured binary compliance status. Our motivation for this work comes from a comparison of the effect of two glucose-lowering medications on a clinical cohort of patients with type 2 diabetes. Here, we consider a causal inference problem assessing how well the two medications work relative to one another on two binary endpoint outcomes: cardiovascular disease-related hospitalization and all-cause mortality. Clinically, these glucose-lowering medications can have differential effects on the intermediate outcome, glucose level over time. Ultimately, we want to compare medication effects on the endpoint outcomes among individuals in the same glucose trajectory stratum while accounting for the heterogeneity in baseline covariates (i.e., to obtain 'principal effects' on the endpoint outcomes). The proposed method involves a three-step model estimation procedure. Step 1 identifies principal strata associated with the intermediate variable using hybrid growth mixture modeling analyses. Step 2 obtains the stratum membership using the pseudoclass technique and derives propensity scores for treatment assignment. Step 3 obtains the stratum-specific treatment effect on the endpoint outcome weighted by inverse propensity probabilities derived from Step 2.

  5. Making genetic biodiversity measurable : a review of statistical multivariate methods to study variability at gene level

    OpenAIRE

    2011-01-01

    Measures of agro-ecosystems genetic variability are essential to sustain scientific-based actions and policies tending to protect the ecosystem services they provide. To build the genetic variability datum it is necessary to deal with a large number and different types of variables. Molecular marker data is highly dimensional by nature, and frequently additional types of information are obtained, as morphological and physiological traits. This way, gene...

  6. A study of culturally syntonic variables in the bilingual/bicultural science classroom

    Science.gov (United States)

    Barba, Robertta H.

    The purpose of this study was to conduct a needs assessment of bilingual/bicultural elementary science classrooms in order to determine if the current instructional environment addresses the educational needs of Hispanic/Latino children. This study examined 57 randomly selected elementary bilingual/bicultural science classrooms in a large metropolitan area of the southwestern United States in terms of culturally syntonic variables (i.e., culture-of-origin beliefs and/or practices that impact the teaching/learning process). Findings from this study indicate that Hispanic/Latino children are receiving science instruction: (a) with culturally asyntonic printed materials, teaching strategies, and supplementary materials, (b) in classrooms that do not use the child's native language, familia learning groups, peer tutoring, or manipulative materials, and (c) with oral and verbal instruction that lack culturally syntonic role models, examples, analogies, and elaborations. Findings from this study imply that changes are needed in pre-service and in-service teacher training, in science textbook formats, and in the scope and focus of elementary school bilingual/bicultural science curriculum and instructional strategies.

  7. Effects of Heart Rate Variability Biofeedback Therapy on Patients with Poststroke Depression: A Case Study

    National Research Council Canada - National Science Library

    Xin Li Tong Zhang Lu-Ping Song Yong Zhang Gui-Gang Zhang Chun-Xiao Xing Hsinchun Chen

    2015-01-01

    ... response to the latter Recently, scientists have started using the heart rate variability (HRV) biofeedback approach to treating patients with depression and found significant clinical efficacy...

  8. Reliability of variables on the North Carolina birth certificate: a comparison with directly queried values from a cohort study.

    Science.gov (United States)

    Vinikoor, Lisa C; Messer, Lynne C; Laraia, Barbara A; Kaufman, Jay S

    2010-01-01

    Birth records are an important source of data for examining population-level birth outcomes, but questions about the reliability of these vital records exist. We sought to assess the reliability of birth certificate data by comparing them with data from a large prospective cohort. Pregnancy, Infection, and Nutrition cohort study participants were matched with their birth certificates to assess agreement for maternal demographics, health behaviours, previous pregnancies and major pregnancy events. Agreement among categorical variables was assessed using percentage agreement and kappa statistics; for continuous variables, Spearman's correlations and concordance correlation coefficients were used. The majority of variables had high agreement between the two data sources, especially for maternal demographic and birth outcome variables. Variables measuring anaemia, gestational diabetes and alcohol consumption showed the lowest correlations. Number of cigarettes smoked and number of previous pregnancies differed by education categories. For most variables, birth records appear to be a good source of reliable information. With the exception of a few variables that differed by education, most variables did not differ by stratum of race or education. Our research further supports the use of birth certificates as a reliable source of population-level data.

  9. Inferring climate variability from nonlinear proxies: application to palaeo-ENSO studies

    Science.gov (United States)

    Emile-Geay, J.; Tingley, M.

    2016-01-01

    Inferring climate from palaeodata frequently assumes a direct, linear relationship between the two, which is seldom met in practice. Here we simulate an idealized proxy characterized by a nonlinear, thresholded relationship with surface temperature, and we demonstrate the pitfalls of ignoring nonlinearities in the proxy-climate relationship. We explore three approaches to using this idealized proxy to infer past climate: (i) methods commonly used in the palaeoclimate literature, without consideration of nonlinearities; (ii) the same methods, after empirically transforming the data to normality to account for nonlinearities; and (iii) using a Bayesian model to invert the mechanistic relationship between the climate and the proxy. We find that neglecting nonlinearity often exaggerates changes in climate variability between different time intervals and leads to reconstructions with poorly quantified uncertainties. In contrast, explicit recognition of the nonlinear relationship, using either a mechanistic model or an empirical transform, yields significantly better estimates of past climate variations, with more accurate uncertainty quantification. We apply these insights to two palaeoclimate settings. Accounting for nonlinearities in the classical sedimentary record from Laguna Pallcacocha leads to quantitative departures from the results of the original study, and it markedly affects the detection of variance changes over time. A comparison with the Lake Challa record, also a nonlinear proxy for El Niño-Southern Oscillation, illustrates how inter-proxy comparisons may be altered when accounting for nonlinearity. The results hold implications for how univariate, nonlinear recorders of normally distributed climate variables are interpreted, compared to other proxy records, and incorporated into multiproxy reconstructions.

  10. Assessment of pH variability at a coastal CO 2 vent for ocean acidification studies

    Science.gov (United States)

    Kerrison, Philip; Hall-Spencer, Jason M.; Suggett, David J.; Hepburn, Leanne J.; Steinke, Michael

    2011-08-01

    Marine environments with naturally high CO 2 concentrations have become important research sites for studying the impacts of future ocean acidification on biological processes. We conducted high temporal resolution pH and temperature measurements in and around a shallow (2.5-3 m) CO 2 vent site off Ischia, Italy in May and June 2008. Loggers were deployed at five stations to monitor water at both the surface and benthos. Our reference station, 500 m from the CO 2 vent, had no noticeable vent influence. It had a naturally high and stable benthic pH (mean 8.16, inter-quartile range (IQ): 8.14-8.18) fluctuating with diel periodicity, presumably driven by community photosynthesis and respiration. A principal component analysis (PCA) revealed that the pH of this station was well constrained by meteorological parameters. In contrast, a station positioned within the vent zone, had a low and very variable benthic mean pH of 7.11 (IQ: 6.91-7.62) with large pH fluctuations not well constrained by a PCA. Any stations positioned within 20 m of the main vent zone had lowered pH, but suffered from abnormally large pH fluctuations making them unsuitable representatives to predict future changes to a shallow coastal environment. Between these extremes, we identified a benthic area with a lower pH of 7.84 (IQ: 7.83-7.88) that retained many of the characteristics of the reference station such as a natural diel pH periodicity and low variability. Our results indicate that a range of pH environments maybe commonplace near CO 2 vents due to their characteristic acidification of benthic water over a wide area. Such environments could become invaluable natural laboratories for ocean acidification research, closely mimicking future CO 2 conditions in a natural setting.

  11. Heart Rate Variability in Children with Attention-Deficit/Hyperactivity Disorder: A Pilot Study

    Science.gov (United States)

    Rukmani, Malligurki Raghurama; Seshadri, Shekhar P.; Thennarasu, Kandavel; Raju, Trichur R.; Sathyaprabha, Talakad N.

    2016-01-01

    Background Attention deficit/hyperactivity disorder (ADHD) is a common childhood neuropsychiatric disorder. Autonomic nervous system plays a vital role in attention, self-regulation, emotional stability and social affiliation, which are affected in ADHD. The prefrontal cortex, which is vital for attention, motor control, emotional regulation and higher order autonomic control, is hypofunctional in ADHD. In addition, catecholamine dysregulation is there. Purpose We hypothesized that there is autonomic dysfunction: reduction in overall heart rate variability (HRV) and sympathovagal imbalance in children with ADHD. Methods Study criteria were drug-naïve ADHD children who were 7-12 years of age of either gender who fulfilled DSM-IV criteria for ADHD and did not have any associated comorbid psychiatric/neurological/medical disorders. Two hundred and seventy ADHD children were screened out of which only 12 were found eligible and 10 participated. Sample size was 20 (cases = 10, age- and gender-matched healthy controls = 10). Short-term HRV of both time and frequency domains were assessed by recording lead II electrocardiogram after using Tell-Show-Do, a behavior shaping technique. Comparison between groups was done using Mann-Whitney and Wilcoxon test. Demographic variables like age, height, weight and body mass index were similar between groups. Results Among time domain parameters, SD of all NN intervals, square root of the mean of the sum of squares of differences between adjacent NN intervals and percentage of count of number of pairs of adjacent NN intervals differing by more than 50 ms were reduced in ADHD group with p < 0.05. Among frequency domain parameters, total power was reduced in ADHD group with p < 0.05, high frequency power (HF) was reduced in ADHD group with p < 0.01 and low frequency power to HF ratio was higher in ADHD group with p < 0.01. Conclusion There is autonomic dysfunction in children with ADHD - reduction in overall HRV with sympathovagal

  12. Nutritional assessment of hospitalized patients in Latin America: association with prognostic variables: The ENHOLA study

    Directory of Open Access Journals (Sweden)

    Juan Carlos Castillo Pineda

    Full Text Available Background and aim: The prevalence of hospital malnutrition (HM is variable, explained by the variability of patients, the nutritional evaluation method used among others. The aim is to determine the frequency of malnutrition in hospitals in Latin America, and estimate its association with mortality and length of hospital stay. Methods: This is an analytical, observational cohort study that included 7,973 patients of both genders, 18 and older, who provided their consent. The survey was administered during the first three days of admission. The nutritional status was estimated using Subjective Global Assessment (SGA and the Nutrition Risk Screening (NRS, body mass index (BMI, percentage of change of weight (PCW and co-morbidities. Serum albumin was obtained from the clinical chart. Length of stay (LOS and the survival status at discharge (dead or alive were also recorded. Results: By SGA: 10.9% had severe malnutrition and 34% moderate malnutrition. By NRS: 36.9% had nutritional risk. Univariate analysis showed that NRS score and serum albumin were prognostic factors for mortality: NRS 3-4 (OR: 2.3, 95% CI: 1.9-2.8, NRS 5-7 (OR: 5.8, 95% CI: 4.9-6.9, serum albumin < 2.5 g/dl, (OR: 2.9, 95% CI: 2.2-3.8. These results were consistent and similar to a multivariate analysis. Both NRS and serum albumin were also independently and clinically associated to LOS. Conclusions: The prevalence of hospital malnutrition in Latin America is high. Our results show that screening with NRS and serum albumin can identify hospital malnutrition as well as providing clinically relevant prognostic value.

  13. Osteosarcoma of the spine: prognostic variables for local recurrence and overall survival, a multicenter ambispective study.

    Science.gov (United States)

    Dekutoski, Mark B; Clarke, Michelle J; Rose, Peter; Luzzati, Alessandro; Rhines, Laurence D; Varga, Peter P; Fisher, Charles G; Chou, Dean; Fehlings, Michael G; Reynolds, Jeremy J; Williams, Richard; Quraishi, Nasir A; Germscheid, Niccole M; Sciubba, Daniel M; Gokaslan, Ziya L; Boriani, Stefano

    2016-07-01

    OBJECTIVE Primary spinal osteosarcomas are rare and aggressive neoplasms. Poor outcomes can occur, as obtaining marginal margins is technically demanding; further Enneking-appropriate en bloc resection can have significant morbidity. The goal of this study is to identify prognostic variables for local recurrence and mortality in surgically treated patients diagnosed with a primary osteosarcoma of the spine. METHODS A multicenter ambispective database of surgically treated patients with primary spine osteosarcomas was developed by AOSpine Knowledge Forum Tumor. Patient demographic, diagnosis, treatment, perioperative morbidity, local recurrence, and cross-sectional survival data were collected. Tumors were classified in 2 cohorts: Enneking appropriate (EA) and Enneking inappropriate (EI), as defined by pathology margin matching Enneking-recommended surgical margins. Prognostic variables were analyzed in reference to local recurrence and survival. RESULTS Between 1987 and 2012, 58 patients (32 female patients) underwent surgical treatment for primary spinal osteosarcoma. Patients were followed for a mean period of 3.5 ± 3.5 years (range 0.5 days to 14.3 years). The median survival for the entire cohort was 6.7 years postoperative. Twenty-four (41%) patients died, and 17 (30%) patients suffered a local recurrence, 10 (59%) of whom died. Twenty-nine (53%) patients underwent EA resection while 26 (47%) patients underwent EI resection with a postoperative median survival of 6.8 and 3.7 years, respectively (p = 0.048). EI patients had a higher rate of local recurrence than EA patients (p = 0.001). Patient age, previous surgery, biopsy type, tumor size, spine level, and chemotherapy timing did not significantly influence recurrence and survival. CONCLUSIONS Osteosarcoma of the spine presents a significant challenge, and most patients die in spite of aggressive surgery. There is a significant decrease in recurrence and an increase in survival with en bloc resection (EA

  14. Extensive X-ray variability studies of NGC 7314 using long XMM-Newton observations

    Science.gov (United States)

    Emmanoulopoulos, D.; McHardy, I. M.; Vaughan, S.; Papadakis, I. E.

    2016-08-01

    We present a detailed X-ray variability study of the low-mass active galactic nuclei (AGN) NGC 7314 using the two newly obtained XMM-Newton observations (140 and 130 ks), together with two archival data sets of shorter duration (45 and 84 ks). The relationship between the X-ray variability characteristics and other physical source properties (such as the black hole mass) are still relatively poorly defined, especially for low-mass AGN. We perform a new, fully analytical, power spectral density (PSD) model analysis method, which will be described in detail in a forthcoming paper, that takes into consideration the spectral distortions, caused by red-noise leak. We find that the PSD in the 0.5-10 keV energy range, can be represented by a bending power law with a bend around 6.7 × 10-5 Hz, having a slope of 0.51 and 1.99 below and above the bend, respectively. Adding our bend time-scale estimate, to an already published ensemble of estimates from several AGN, supports the idea that the bend time-scale depends linearly only on the black hole mass and not on the bolometric luminosity. Moreover, we find that as the energy range increases, the PSD normalization increases and there is a hint that simultaneously the high-frequency slope becomes steeper. Finally, the X-ray time-lag spectrum of NGC 7314 shows some very weak signatures of relativistic reflection, and the energy resolved time-lag spectrum, for frequencies around 3 × 10-4 Hz, shows no signatures of X-ray reverberation. We show that the previous claim about ks time delays in this source, is simply an artefact induced by the minuscule number of points entering during the time-lag estimation in the low-frequency part of the time-lag spectrum (i.e. below 10-4 Hz).

  15. [Study on three-dimension spatial variability of regional soil salinity based on spectral indices].

    Science.gov (United States)

    Liu, Guang-Ming; Wu, Ya-Kun; Yang, Jin-Song; Yu, Shi-Peng

    2013-10-01

    In order to illustrate the three-dimension spatial variability of soil salinity in central China flood area of the Yellow river, integrated soil sampling data and remote sensing data, spectral indices and inverse distance weighting (IDW) method were applied to the estimation and simulation of three-dimension spatial distribution of soil salinity. The study was carried out in typical central China flood area of the Yellow river in Fengqiu County, Henan Province, China. The electrical conductivity of the saturation extract (EC1: 5) of 505 soil samples collected at 101 points was measured. The results indicated that the coefficient of variation of soil salinity at each soil layer is from 0.218 to 0.324 and exhibited the moderate spatial variability. The average of soil electrical conductivity is from 0.121 to 0.154 ds x m(-1). The 2 820 three-dimension spatial scattered data for soil electrical conductivity were taken at soil salinity mapping interpreted by spectral indices and soil electrical conductivity. Three-dimension IDW interpolation showed that a large area of high soil salinity mainly located in the region of Tianran canal and the along of the Yellow river. The shape of the soil salinity profile was downward flowed, revealing soil salinity increasing with depth in whole soil profile and soil salinity accumulated in the subsoil. The accuracy of the predictions was tested using 20 soil sampled points. The root mean square error (RMSE) of calibration for three-dimension distribution of soil salinity showed that the IDW method based on spectral indices was ideal. The research results can provide theoretical foundations to the management and utilization of salt-affected land in China flood area, especially in the Yellow river zone.

  16. Study of the variables associated with local complement activation in IgA nephropathy.

    Science.gov (United States)

    Segarra-Medrano, Alfons; Carnicer-Caceres, Clara; Valtierra-Carmeno, Naiara; Agraz-Pamplona, Irene; Ramos-Terrades, Natalia; Jatem Escalante, Elías; Ostos-Roldan, Elena

    1. To identify the variables that are associated with urinary levels of properdin, MBL, C4d, and C5b-9 in patients with idiopathic IgA nephropathy. 2. To analyse whether urinary levels of MBL and/or C4d are useful for identifying the presence of mesangial deposits of C4d/MBL. A total of 96 patients with IgA nephropathy were studied. Demographic, clinical and biochemical variables were recorded at the time of diagnosis. Renal lesions were quantified using the Oxford classification. Immunohistochemical staining for MBL, MASP-2, properdin, C4d, and C5b-9 was performed in kidney biopsies, and in urine, the levels of properdin, MBL, C4d and C5b-9 were determined. In multivariate analysis, the independent predictors of C4d and MBL levels in urine were the mesangial deposits of each protein and, to a lesser extent, the urinary protein excretion. The independent predictors of urinary levels of C5b-9 were MBL properdin and proteinuria. Urinary excretion of C4d had a sensitivity of 90% (95% CI: 58,7 to 99) and a specificity of 73% (95% CI: 54-87) for detecting mesangial C4d deposits, and the level of MBL had a sensitivity of 83.9% (95% CI: 62-95) and a specificity of 81.6% (95% CI: 65-92) for identifying mesangial deposits of MBL. The main predictor of urinary concentration of C4d and MBL was the presence of their respective mesangial deposits. Urine MBL may contribute to complement activation in the tubular luz through the lectin pathway. Urinary levels of MBL and C4d could be sensitive and specific biomarkers for the identification of patients with mesangial deposits of MBL and C4d. Copyright © 2017. Published by Elsevier España, S.L.U.

  17. Studying radon exhalation rates variability from phosphogypsum piles in the SW of Spain

    Energy Technology Data Exchange (ETDEWEB)

    López-Coto, I., E-mail: israel.lopez@dfa.uhu.es [Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva (Spain); Mas, J.L. [Dpto. Física Aplicada I. Escuela Politécnica Superior, University of Sevilla, C/Virgen de Africa 7, 41012 Sevilla (Spain); Vargas, A. [Universitat Politècnica de Catalunya, Instituto de Técnicas Energéticas, Campus Sud Edificio ETSEIB, Planta 0, Pabellón C, Av. Diagonal 647, 08028 Barcelona (Spain); Bolívar, J.P. [Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva (Spain)

    2014-09-15

    Highlights: • Variability of radon exhalation rates from PG piles has been studied using numerical simulation supported by experimental data. • Most relevant parameters controlling the exhalation rate are radon potential and moisture saturation. • Piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. • A proposed cover here is expected to allow exhalation rates reductions up to 95%. - Abstract: Nearly 1.0 × 10{sup 8} tonnes of phosphogypsum were accumulated during last 50 years on a 1200 ha disposal site near Huelva town (SW of Spain). Previous measurements of exhalation rates offered very variable values, in such a way that a worst case scenario could not be established. Here, new experimental data coupled to numerical simulations show that increasing the moisture contents or the temperature reduces the exhalation rate whilst increasing the radon potential or porosity has the contrary effect. Once the relative effects are compared, it can be drawn that the most relevant parameters controlling the exhalation rate are radon potential (product of emanation factor by {sup 226}Ra concentration) and moisture saturation of PG. From wastes management point of view, it can be concluded that piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. Furthermore, a proposed cover here is expected to allow exhalation rates reductions up to 95%. We established that the worst case scenario corresponds to a situation of extremely dry winter. Under these conditions, the radon exhalation rate (0.508 Bq m{sup −2} s{sup −1}) would be below though close to the upper limit established by U.S.E.P.A. for inactive phopsphogypsum piles (0.722 Bq m{sup −2} s{sup −1})

  18. Analysis of Intra- and Intersubject Variability in Oral Drug Absorption in Human Bioequivalence Studies of 113 Generic Products.

    Science.gov (United States)

    Sugihara, Masahisa; Takeuchi, Susumu; Sugita, Masaru; Higaki, Kazutaka; Kataoka, Makoto; Yamashita, Shinji

    2015-12-07

    In this study, the data of 113 human bioequivalence (BE) studies of immediate release (IR) formulations of 74 active pharmaceutical ingredients (APIs) conducted at Sawai Pharmaceutical Co., Ltd., was analyzed to understand the factors affecting intra- and intersubject variabilities in oral drug absorption. The ANOVA CV (%) calculated from area under the time-concentration curve (AUC) in each BE study was used as an index of intrasubject variability (Vintra), and the relative standard deviation (%) in AUC was used as that of intersubject variability (Vinter). Although no significant correlation was observed between Vintra and Vinter of all drugs, Vintra of class 3 drugs was found to increase in association with a decrease in drug permeability (P(eff)). Since the absorption of class 3 drugs was rate-limited by the permeability, it was suggested that, for such drugs, the low P(eff) might be a risk factor to cause a large intrasubject variability. To consider the impact of poor water solubility on the variability in BE study, a parameter of P(eff)/Do (Do; dose number) was defined to discriminate the solubility-limited and dissolution-rate-limited absorption of class 2 drugs. It was found that the class 2 drugs with a solubility-limited absorption (P(eff)/Do < 0.149 × 10(-4) cm/s) showed high intrasubject variability. Furthermore, as a reason for high intra- or intersubject variability in AUC for class 1 drugs, effects of drug metabolizing enzymes were investigated. It was demonstrated that intrasubject variability was high for drugs metabolized by CYP3A4 while intersubject variability was high for drugs metabolized by CYP2D6. For CYP3A4 substrate drugs, the Km value showed the significant relation with Vintra, indicating that the affinity to the enzyme can be a parameter to predict the risk of high intrasubject variability. In conclusion, by analyzing the in house data of human BE study, low permeability, solubility-limited absorption, and high affinity to CYP3A4 are

  19. Sneezes, gasps and yawns in the evolution of Cataclsmic Variables: a spectroscopic study of winds

    Science.gov (United States)

    Kafka, Stella; Honeycutt, R. Kent; Hoard, Don

    2008-02-01

    Cataclysmic variables (CVs) sometimes show evidence for bi-polar winds arising from the accretion process. These winds carry away mass and angular momentum, likely affecting the evolution of the system. For the most part, it has only been possible to study such winds by means of the P Cygni profiles seen in space-UV resonance lines. However, we have found that a number of CVs show wind lines in the optical region of the spectrum, providing the opportunity for ground-based study of changes in the wind to determine its origin, time scales, kinematics, and geometry. Distinct differences in the behaviors of singlet and triplet He I lines provide a means to distinguish wind and disk components; however we know very little about the secular and orbital changes in the winds, or the types of CVs in which winds occur. This proposal is to enrich our on- going spectroscopic program studying for P Cygni profiles in the He I triplet lines. These data will reveal the kinds of CVs that have winds and how often winds appear, information critical to understanding if such winds contribute to the angular momentum loss that drives CV evolution.

  20. Study the Effect of Hydrolysis Variables on the Production of Soya Proteins Hydrolysis

    Directory of Open Access Journals (Sweden)

    Sundus H.Ahammed

    2009-01-01

    Full Text Available This study was conducted to determine the effects of concentration of hydrochloric acids, temperature, and time on the hydrolysis of soya proteins (defatted soya flour by determining the value of total protein nitrogen concentration, and amino nitrogen concentration of protein, peptides, and amino acids, and then calculated the hydrolysis rate of proteins.The variables of the conditions of hydrolysis process was achieved in this study with the following range value of tests parameter: •Concentration of HCl solution ranged between 1-7 N, •Hydrolysis temperature ranged between 35-95 C, and•The time of hydrolysis period ranged between 0.5-24 hr.Experiments were designed according to the central composite rotatable design.The practical study has shown the possibility of decreasing the negative effect of the acid on the biological characteristics of the protein; then affecting the possibility of using the product for biological purposes (for medical and microbiological laboratories by:•Decreasing the acid concentration used in the process of hydrolysis, firstly, and •Decreasing the temperature of the hydrolysis process, secondly, and then •Increasing the period of the time of hydrolysis process, thirdly.

  1. Is the Dark Triad Better Studied Using a Variable- or a Person-Centered Approach? An Exploratory Investigation

    Science.gov (United States)

    Kam, Chester Chun Seng; Zhou, Mingming

    2016-01-01

    Despite Allport’s early call to study personality as a coordinated system of traits within individual rather than separate traits, researchers often assume personality variables are largely distinct, independent characteristics. In the current research, we examined the usual assumption that Dark Triad traits (narcissism, psychopathy, and Machiavellianism) are best studied using a variable-centered (dimensional), rather than a person-centered (taxonic), approach. Results showed that a variable-centered approach is appropriate in understanding the Dark Triad, and yet individuals scoring high on one Dark Triad dimension also tend to score high on other dimensions. Based on these results, we concluded that it is appropriate to study individual differences in the Dark Triad (inferences based on persons) by capturing the common variance among the three traits using a variable-centered approach, rather than treating these traits as independent or uncoordinated characteristics. PMID:27580224

  2. The Notion of Variability in Software Architecture – Results from a Preliminary Exploratory Study

    NARCIS (Netherlands)

    Galster, Matthias; Avgeriou, Paris

    2011-01-01

    Context: In the software product line domain, the concept of variability is well recognized. However, variability in the context of software architecture still seems to be poorly understood. Objective: In this paper, we aim at contributing to the development of a basic understanding of the notion of

  3. Analyzing Regression-Discontinuity Designs with Multiple Assignment Variables: A Comparative Study of Four Estimation Methods

    Science.gov (United States)

    Wong, Vivian C.; Steiner, Peter M.; Cook, Thomas D.

    2013-01-01

    In a traditional regression-discontinuity design (RDD), units are assigned to treatment on the basis of a cutoff score and a continuous assignment variable. The treatment effect is measured at a single cutoff location along the assignment variable. This article introduces the multivariate regression-discontinuity design (MRDD), where multiple…

  4. A longitudinal study of blood pressure variability in African-American and European American youth

    NARCIS (Netherlands)

    Li, Zhibin; Snieder, Harold; Su, Shaoyong; Harshfield, Gregory A.; Treiber, Frank A.; Wang, Xiaoling

    2010-01-01

    Objectives High blood pressure variability is increasingly used as a predictor of target-organ damage and cardiovascular events. However, little is known about blood pressure variability changes with age and its possible sociodemographic, anthropometric, and genetic moderators. Methods Twenty-four-h

  5. The Notion of Variability in Software Architecture – Results from a Preliminary Exploratory Study

    NARCIS (Netherlands)

    Galster, Matthias; Avgeriou, Paris

    2011-01-01

    Context: In the software product line domain, the concept of variability is well recognized. However, variability in the context of software architecture still seems to be poorly understood. Objective: In this paper, we aim at contributing to the development of a basic understanding of the notion of

  6. Multiwavelength variability study and search for periodicity of PKS 1510-089

    Science.gov (United States)

    Castignani, G.; Pian, E.; Belloni, T. M.; D'Ammando, F.; Foschini, L.; Ghisellini, G.; Pursimo, T.; Bazzano, A.; Beckmann, V.; Bianchin, V.; Fiocchi, M. T.; Impiombato, D.; Raiteri, C. M.; Soldi, S.; Tagliaferri, G.; Treves, A.; Türler, M.

    2017-05-01

    Context. Blazars are the most luminous and variable active galactic nuclei (AGNs). They are thus excellent probes of accretion and emission processes close to the central engine. Aims: We concentrate here on PKS 1510-089 (z = 0.36), a blazar belonging to the flat-spectrum radio quasar subclass, an extremely powerful gamma-ray source and one of the brightest in the Fermi-LAT catalog. We aim to study the complex variability of this blazar's bright multiwavelength spectrum, to identify the physical parameters responsible for the variations and the timescales of possible recurrence and quasi-periodicity at high energies. Methods: The blazar PKS 1510-089 was observed twice in hard X-rays with the IBIS instrument onboard INTEGRAL during the flares of Jan. 2009 and Jan. 2010, and simultaneously with Swift and the Nordic Optical Telescope (NOT), in addition to the constant Fermi monitoring. We also measured the optical polarization in several bands on 18 Jan. 2010 at the NOT.Using these and archival data we constructed historical light curves at gamma-to-radio wavelengths covering nearly 20 yr and applied tests of fractional and correlated variability. We assembled spectral energy distributions (SEDs) based on these data and compared them with those at two previous epochs, by applying a model based on synchrotron and inverse Compton radiation from blazars. Results: The modeling of the SEDs suggests that the physical quantities that undergo the largest variations are the total power injected into the emitting region and the random Lorentz factor of the electron distribution cooling break, that are higher in the higher gamma-ray states. This suggests a correlation of the injected power with enhanced activity of the acceleration mechanism. The cooling likely takes place at a distance of 1000 Schwarzschild radii( 0.03 pc) from the central engine - a distance muchsmaller than the broad line region (BLR) radius.The emission at a few hundred GeV can be reproduced with inverse

  7. Examination of Studying Approaches of Students at School of Physical Education and Sports in Terms of Different Variables

    Science.gov (United States)

    Dereceli, Cagatay

    2017-01-01

    This study aims to examine studying approaches of the students of physical education and school of physical and sports according to various variables. The data of the study conducted in the general scanning model has been collected from 478 students in 2016-2017 teaching year. Studying Approaches Scale has been used to collect data. Besides…

  8. Acute low back pain is marked by variability: An internet-based pilot study

    Directory of Open Access Journals (Sweden)

    Katz Jeffrey N

    2011-10-01

    Full Text Available Abstract Background Pain variability in acute LBP has received limited study. The objectives of this pilot study were to characterize fluctuations in pain during acute LBP, to determine whether self-reported 'flares' of pain represent discrete periods of increased pain intensity, and to examine whether the frequency of flares was associated with back-related disability outcomes. Methods We conducted a cohort study of acute LBP patients utilizing frequent serial assessments and Internet-based data collection. Adults with acute LBP (lasting ≤3 months completed questionnaires at the time of seeking care, and at both 3-day and 1-week intervals, for 6 weeks. Back pain was measured using a numerical pain rating scale (NPRS, and disability was measured using the Oswestry Disability Index (ODI. A pain flare was defined as 'a period of increased pain lasting at least 2 hours, when your pain intensity is distinctly worse than it has been recently'. We used mixed-effects linear regression to model longitudinal changes in pain intensity, and multivariate linear regression to model associations between flare frequency and disability outcomes. Results 42 of 47 participants (89% reported pain flares, and the average number of discrete flare periods per patient was 3.5 over 6 weeks of follow-up. More than half of flares were less than 4 hours in duration, and about 75% of flares were less than one day in duration. A model with a quadratic trend for time best characterized improvements in pain. Pain decreased rapidly during the first 14 days after seeking care, and leveled off after about 28 days. Patients who reported a pain flare experienced an almost 3-point greater current NPRS than those not reporting a flare (mean difference [SD] 2.70 [0.11]; p ß [SE} 0.28 (0.08; p = 0.002. Conclusions Acute LBP is characterized by variability. Patients with acute LBP report multiple distinct flares of pain, which correspond to discrete increases in pain intensity. A

  9. MEASUREMENT-TO-MEASUREMENT BLOOD PRESSURE VARIABILITY IS RELATED TO COGNITIVE PERFORMANCE: THE MAINE-SYRACUSE STUDY

    Science.gov (United States)

    Crichton, Georgina E.; Elias, Merrill F.; Dore, Gregory A.; Torres, Rachael V.; Robbins, Michael A.

    2014-01-01

    The objective was to investigate the association between variability in blood pressure and cognitive function for sitting, standing and reclining blood pressure values, and variability derived from all 15 measures. In previous studies only sitting blood pressure values have been examined, and only a few cognitive measures have been employed. A secondary objective was to examine associations between blood pressure variability and cognitive performance in hypertensive individuals stratified by treatment success. Cross-sectional analyses were performed on 972 participants of the Maine Syracuse Study for whom 15 serial blood pressure clinic measures (5 sitting, 5 recumbant and 5 standing) were obtained, prior to testing of cognitive performance. Using all 15 measures, higher variability in systolic and diastolic blood pressure was associated with poorer performance on multiple measures of cognitive performance, independent of demographic factors, cardiovascular risk factors, and pulse pressure. When sitting, reclining and standing systolic blood pressure values were compared, only variability in standing blood pressure was related to measures of cognitive performance. However, for diastolic blood pressure, variability in all three positions was related to cognitive performance. Mean blood pressure values were weaker predictors of cognition. Furthermore, higher overall variability in both systolic and diastolic blood pressure was associated with poorer cognitive performance in unsuccessfully treated hypertensive individuals (with blood pressure ≥140/90 mmHg), but these associations were not evident in those with controlled hypertension. PMID:25156168

  10. The study of the variability of anticipatory postural adjustments in patients with recurrent non-specific low back pain.

    Science.gov (United States)

    Hedayati, Rozita; Kahrizi, Sedighe; Parnianpour, Mohammad; Bahrami, Fariba; Kazemnejad, Anushiravan; Mobini, Bahram

    2014-01-01

    Intrinsic variability is present in all actions, including repetitive tasks. The aim of this study was to evaluate the variability of anticipatory postural adjustments (APAs) of trunk muscles in participants with low back pain (LBP). The study included 21 participants with recurrent non-specific LBP (15 men, 6 women) and 21 healthy volunteers. Standard deviation of electromyographic activity of the external oblique (EO), transverse abdominis/internal oblique (TrA/IO), and erector spinae (ES) muscles onset relative to deltoid muscle onset was recorded in 75 rapid arm flexions, and the correlation with the participants' avoidance belief (the FABQ score) and disability (the Roland-Morris Questionnaire score) was statistically analyzed. participants with LBP exhibited less variability in timing of APAs of the TrA/IO muscle compared with the control group (P=0.047). The timing of APAs of the TrA/IO muscle was significantly correlated with the FABQ score (P=0.006). There was no significant correlation between this variable and disability (P=0.09). Decrease in variability of the timing of APA of the EO (P=0.45) and ES (P=0.6) muscles was not significant. The variability of the postural responses of participants with LBP decreased. Restoring variability in postural control responses might be a goal in rehabilitating these patients.

  11. Common Variable Immunodeficiency (CVID)

    Science.gov (United States)

    ... with facebook share with twitter share with linkedin Common Variable Immunodeficiency (CVID) Common variable immunodeficiency (CVID) is ... and acquired agammaglobulinemia. Why Is the Study of Common Variable Immunodeficiency (CVID) a Priority for NIAID? CVID ...

  12. A Variable-resolution Surface Wave Dispersion Study of Eurasia, North Africa, and Surrounding Regions

    Energy Technology Data Exchange (ETDEWEB)

    Pasyanos, M E

    2005-03-21

    This paper presents the results of a large-scale study of surface wave dispersion performed across Eurasia and North Africa. Improvements were made to previous surface wave work by enlarging the study region, increasing path density, improving spatial resolution, and expanding the period range. This study expands the coverage area northwards and eastwards relative to a previous dispersion analysis, which covered only North Africa and the Middle East. We have significantly increased the number of seismograms examined and group velocity measurements made. We have now made good quality dispersion measurements for about 30,000 Rayleigh wave and 20,000 Love wave paths, and have incorporated measurements from several other researchers into the study. A conjugate gradient method was employed for the group velocity tomography, which improved the inversion from the previous study by adopting a variable smoothness. This technique allows us to go to higher resolution where the data allow without producing artifacts. The current results include both Love and Rayleigh wave inversions across the region for periods from 7 to 100 seconds at 1{sup o} resolution. Short period group velocities are sensitive to slow velocities associated with large sedimentary features such as the Caspian Sea, West Siberian Platform, Mediterranean Sea, Bay of Bengal, Tarim Basin, and Persian Gulf. Intermediate periods are sensitive to differences in crustal thickness, such as those between oceanic and continental crust or along orogenic zones and continental plateaus. At longer periods, fast velocities are consistently found beneath cratons while slow upper mantle velocities occur along rift systems, subduction zones, and collision zones such as the Tethys Belt. We have compared the group velocities at various periods with features such as sediment thickness, topographic height, crustal thickness, proximity to plate boundaries, lithospheric age and lithospheric thickness, and find significant

  13. Phylogenetic and Molecular Variability Studies Reveal a New Genetic Clade of Citrus leprosis virus C.

    Science.gov (United States)

    Ramos-González, Pedro Luis; Chabi-Jesus, Camila; Guerra-Peraza, Orlene; Breton, Michèle Claire; Arena, Gabriella Dias; Nunes, Maria Andreia; Kitajima, Elliot Watanabe; Machado, Marcos Antonio; Freitas-Astúa, Juliana

    2016-06-06

    Citrus leprosis virus C (CiLV-C) causes a severe disease affecting citrus orchards in the Western hemisphere. This study reveals the molecular variability of the virus by analyzing four genomic regions (p29, p15, MP and RNA2-intergenic region) distributed over its two RNAs. Nucleotide diversity (π) values were relatively low but statistically different over the analyzed genes and subpopulations, indicating their distinct evolutionary history. Values of πp29 and πMP were higher than those of πp15 and πRNA2-IR, whereas πMP was increased due to novel discovered isolates phylogenetically clustered in a divergent clade that we called SJP. Isolate BR_SP_SJP_01 RNA1 and RNA2 sequences, clade SJP, showed an identity of 85.6% and 88.4%, respectively, with those corresponding to CiLV-C, the type member of the genus Cilevirus, and its RNA2 5'-proximal region was revealed as a minor donor in a putative inter-clade recombination event. In addition to citrus, BR_SP_SJP_01 naturally infects the weed Commelina benghalensis and is efficiently transmitted by Brevipalpus yothersi mites. Our data demonstrated that negative selection was the major force operating in the evaluated viral coding regions and defined amino acids putatively relevant for the biological function of cilevirus proteins. This work provides molecular tools and sets up a framework for further epidemiological studies.

  14. The effects of workload on respiratory variables in simulated flight: a preliminary study.

    Science.gov (United States)

    Karavidas, Maria Katsamanis; Lehrer, Paul M; Lu, Shou-En; Vaschillo, Evgeny; Vaschillo, Bronya; Cheng, Andrew

    2010-04-01

    In this pilot study, we investigated respiratory activity and end-tidal carbon dioxide (P(et)CO(2)) during exposure to varying levels of work load in a simulated flight environment. Seven pilots (age: 34-60) participated in a one-session test on the Boeing 737-800 simulator. Physiological data were collected while pilots wore an ambulatory multi-channel recording device. Respiratory variables, including inductance plethysmography (respiratory pattern) and pressure of end-tidal carbon dioxide (P(et)CO(2)), were collected demonstrating change in CO(2) levels proportional to changes in flight task workload. Pilots performed a set of simulation flight tasks. Pilot performance was rated for each task by a test pilot; and self-report of workload was taken using the NASA-TLX scale. Mixed model analysis revealed that respiration rate and minute ventilation are significantly associated with workload levels and evaluator scores controlling for "vanilla baseline" condition. Hypocapnia exclusively occurred in tasks where pilots performed more poorly. This study was designed as a preliminary investigation in order to develop a psychophysiological assessment methodology, rather than to offer conclusive findings. The results show that the respiratory system is very reactive to high workload conditions in aviation and suggest that hypocapnia may pose a flight safety risk under some circumstances. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Patients’ Dignity and Its Relationship with Contextual Variables: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Mohammad Zirak

    2017-03-01

    Full Text Available Introduction: Dignity is considered as fundamental human needs and recognized as one of the central concepts in nursing science. The aim of this study was to assess the extent to which patients’ dignity is respected and to evalutae its relationship with contextual variables. Methods: This cross-sectional study was conducted on 256 hospitalized patients in the two teaching hospitals affiliated to Zanjan University of medical sciences, Iran. Data were collected by a questionnaire consist of two sections: (a demographic characteristics, and (b patient dignity including 32 questions. Data were analyzed by SPSS (ver.13 software using independent t-test, ANOVA and Pearson correlation. Results: The result showed that the mean (standard deviation of total score of patient’s dignity was 108.17 (25.28. According to the result, the majority of the respondents (76.2% were not aware of patient’s rights. There was a significant difference in mean scores of total dignity between single and married persons, living in city or village, and hospitalization in Moosavi and Valiasr hospital. Conclusion: Health care systems should take the provision of the patients' dignity into account through using a comprehensive educational program for informing of patient, family members, and health professionals about patients’ dignity.

  16. A Study of Nonlinear Variable Viscosity in Finite-Length Tube with Peristalsis

    Directory of Open Access Journals (Sweden)

    Y. Abd Elmaboud

    2014-01-01

    Full Text Available Peristaltic motion of an incompressible Newtonian fluid with variable viscosity induced by periodic sinusoidal traveling wave propagating along the walls of a finite-length tube has been investigated. A perturbation method of solution is sought. The viscosity parameter α (α << 1 is chosen as a perturbation parameter and the governing equations are developed up to the first-order in the viscosity parameter (α. The analytical solution has been derived for the radial velocity at the tube wall, the axial pressure gradient across the length of the tube, and the wall shear stress under the assumption of low Reynolds number and long wavelength approximation. The impacts of physical parameters such as the viscosity and the parameter determining the shape of the constriction on the pressure distribution and on the wall shear stress for integral and non-integral number of waves are illustrated. The main conclusion that can be drawn out of this study is that the peaks of pressure fluctuate with time and attain different values with non-integral numbers of peristaltic waves. The considered problem is very applicable in study of biological flow and industrial flow.

  17. Associations between climate variability, unemployment and suicide in Australia: a multicity study.

    Science.gov (United States)

    Qi, Xin; Hu, Wenbiao; Page, Andrew; Tong, Shilu

    2015-05-12

    A number of studies have examined the associations of suicide with meteorological variables (MVs) and socioeconomic status but the results are inconsistent. This study assessed whether MVs and unemployment were associated with suicide in eight Australian capital cities. Data on suicide, population and unemployment rate (UER) between 1985 and 2005 were from the Australian Bureau of Statistics. MVs was provided by Australian Bureau of Meteorology. A generalized linear regression model with Poisson link was applied to explore the association of suicide with MVs and UER. Temperature difference (ΔT, the difference in mean temperature between current month and previous one month) was positively associated with suicide in Sydney, Melbourne, Brisbane and Hobart. There was also a significant and positive association between UER and suicide in Sydney, Melbourne, Brisbane and Perth. MVs had more significant associations with violent suicide than that of non-violent suicide. There were no consistent associations between other MVs and suicide. A significant interaction between ΔT and UER on suicide was found in Sydney, Melbourne and Brisbane, such that increased temperature amplified the magnitude of the association between UER and suicide. ΔT and UER appeared to jointly influence the occurrence of suicide in Australian capital cities. This finding may have implications for developing effective suicide prevention strategies.

  18. Heart rate variability (HRV) and posttraumatic stress disorder (PTSD): a pilot study.

    Science.gov (United States)

    Tan, Gabriel; Dao, Tam K; Farmer, Lorie; Sutherland, Roy John; Gevirtz, Richard

    2011-03-01

    Exposure to combat experiences is associated with increased risk of developing Post Traumatic Stress Disorder. Prolonged exposure therapy and cognitive processing therapy have garnered a significant amount of empirical support for PTSD treatment; however, they are not universally effective with some patients continuing to struggle with residual PTSD symptoms. Heart rate variability (HRV) is a measure of the autonomic nervous system functioning and reflects an individual's ability to adaptively cope with stress. A pilot study was undertaken to determine if veterans with PTSD (as measured by the Clinician-Administered PTSD Scale and the PTSD Checklist) would show significantly different HRV prior to an intervention at baseline compared to controls; specifically, to determine whether the HRV among veterans with PTSD is more depressed than that among veterans without PTSD. The study also aimed at assessing the feasibility, acceptability, and potential efficacy of providing HRV biofeedback as a treatment for PTSD. The findings suggest that implementing an HRV biofeedback as a treatment for PTSD is effective, feasible, and acceptable for veterans. Veterans with combat-related PTSD displayed significantly depressed HRV as compared to subjects without PTSD. When the veterans with PTSD were randomly assigned to receive either HRV biofeedback plus treatment as usual (TAU) or just TAU, the results indicated that HRV biofeedback significantly increased the HRV while reducing symptoms of PTSD. However, the TAU had no significant effect on either HRV or symptom reduction. A larger randomized control trial to validate these findings appears warranted.

  19. XMM-Newton reveals ~100 new LMXBs in M31 from variability studies

    CERN Document Server

    Barnard, R; Tonkin, C; Kolb, U; Osborne, J P

    2005-01-01

    We have conducted a survey of X-ray sources in XMM-Newton observations of M31, examining their power density spectra (PDS) and spectral energy distributions (SEDs). Our automated source detection yielded 535 good X-ray sources; to date, we have studied 225 of them. In particular, we examined the PDS because low mass X-ray binaries (LMXBs) exhibit two distinctive types of PDS. At low accretion rates, the PDS is characterised by a broken power law, with the spectral index changing from ~0 to ~1 at some frequency in the range \\~0.01--1 Hz; we refer to such PDS as Type A. At higher accretion rates, the PDS is described by a simple power law; we call these PDS Type B. Of the 225 sources studied to date, 75 exhibit Type A variability, and are almost certainly LMXBs, while 6 show Type B but not Type A, and are likely LMXBs. Of these 81 candidate LMXBs, 71 are newly identified in this survey; furthermore, they are mostly found near the centre of M31. Furthermore, most of the X-ray population in the disc are associate...

  20. Parametric study of influence of stiffener variables on postbuckling response of frame-stiffened composite panels

    Science.gov (United States)

    Sanz-Douglass, Gabriela J.

    Traditional aircraft composite stiffened panels are designed to avoid buckling of the skin at service loads, to prevent initiation and growth of delamination damages. In stitched composites, the stitching provides reinforcement against delamination; therefore, the structure can be designed for operation in a post buckled state with local skin buckling. The novel stitched stiffened composite panel concept titled Pultruded-Rod Stiffened Efficient Unitized Structure, PRSEUS, was designed specifically for operating in the postbuckling regime, yet the nonlinear postbuckling behavior of PRSEUS has not been explored fully. This thesis presents a finite element analysis based trade study to understand influence of frame stiffener design variables on the nonlinear postbuckling response of the PRSEUS panel concept. The trade study allowed exploration of the design space as a first step towards design optimization. It also allowed discovery of some of the challenges of post processing that must be addressed to enable an automated surrogate based design optimization of the PRESUS stiffened panel concept for operation in postbuckling regimes.

  1. Towards powerful experimental and statistical approaches to study intraindividual variability in labile traits

    Science.gov (United States)

    Fanson, Benjamin G.; Beckmann, Christa; Biro, Peter A.

    2016-01-01

    There is a long-standing interest in behavioural ecology, exploring the causes and correlates of consistent individual differences in mean behavioural traits (‘personality’) and the response to the environment (‘plasticity’). Recently, it has been observed that individuals also consistently differ in their residual intraindividual variability (rIIV). This variation will probably have broad biological and methodological implications to the study of trait variation in labile traits, such as behaviour and physiology, though we currently need studies to quantify variation in rIIV, using more standardized and powerful methodology. Focusing on activity rates in guppies (Poecilia reticulata), we provide a model example, from sampling design to data analysis, in how to quantify rIIV in labile traits. Building on the doubly hierarchical generalized linear model recently used to quantify individual differences in rIIV, we extend the model to evaluate the covariance between individual mean values and their rIIV. After accounting for time-related change in behaviour, our guppies substantially differed in rIIV, and it was the active individuals that tended to be more consistent (lower rIIV). We provide annotated data analysis code to implement these complex models, and discuss how to further generalize the model to evaluate covariances with other aspects of phenotypic variation. PMID:27853550

  2. The Association between Work-Related Rumination and Heart Rate Variability: A Field Study

    Science.gov (United States)

    Cropley, Mark; Plans, David; Morelli, Davide; Sütterlin, Stefan; Inceoglu, Ilke; Thomas, Geoff; Chu, Chris

    2017-01-01

    The objective of this study was to examine the association between perseverative cognition in the form of work-related rumination, and heart rate variability (HRV). We tested the hypothesis that high ruminators would show lower vagally mediated HRV relative to low ruminators during their leisure time. Individuals were classified as being low (n = 17) or high ruminators (n = 19), using the affective scale on the work-related rumination measure. HRV was assessed using a wrist sensor band (Microsoft Band 2). HRV was sampled between 8 pm and 10 pm over three workday evenings (Monday to Wednesday) while individuals carried out their normal evening routines. Compared to the low ruminators, high affective ruminators demonstrated lower HRV in the form of root mean square successive differences (RMSSDs), relative to the low ruminators, indicating lower parasympathetic activity. There was no significant difference in heart rate, or activity levels between the two groups during the recording periods. The current findings of this study may have implications for the design and delivery of interventions to help individuals unwind post work and to manage stress more effectively. Limitations and implications for future research are discussed. PMID:28197087

  3. Patients’ Dignity and Its Relationship with Contextual Variables: A Cross-Sectional Study

    Science.gov (United States)

    Zirak, Mohammad; Ghafourifard, Mansour; Aliafsari Mamaghani, Ebrahim

    2017-01-01

    Introduction: Dignity is considered as fundamental human needs and recognized as one of the central concepts in nursing science. The aim of this study was to assess the extent to which patients’ dignity is respected and to evalutae its relationship with contextual variables. Methods: This cross-sectional study was conducted on 256 hospitalized patients in the two teaching hospitals affiliated to Zanjan University of medical sciences, Iran. Data were collected by a questionnaire consist of two sections: (a) demographic characteristics, and (b) patient dignity including 32 questions. Data were analyzed by SPSS (ver.13) software using independent t-test, ANOVA and Pearson correlation. Results: The result showed that the mean (standard deviation) of total score of patient’s dignity was 108.17 (25.28). According to the result, the majority of the respondents (76.2%) were not aware of patient’s rights. There was a significant difference in mean scores of total dignity between single and married persons, living in city or village, and hospitalization in Moosavi and Valiasr hospital. Conclusion: Health care systems should take the provision of the patients' dignity into account through using a comprehensive educational program for informing of patient, family members, and health professionals about patients’ dignity. PMID:28299297

  4. Coherence of heart rate variability and local physical fields in monitoring studies

    Science.gov (United States)

    Tuzhilkin, D. A.; Borodin, A. S.

    2015-11-01

    Technological advances have led to a substantial modification of the physical fields of the environment, which could affect the status of living organisms under their constant exposure. In this study, the activity of human cardiovascular system under the influence of a complex natural physical environmental factors investigated. The study was conducted on a representative homogeneous sample (44 persons aged 19 to 22 years) by simultaneous monitoring of electrocardiograms and natural physical fields in Tomsk (geomagnetic field, meteorological parameters - temperature, pressure and humidity, surface wind speed, the parameters of the Schumann resonance - amplitude, frequency and quality factor of the first four modes in the range of 6 to 32 Hz, the power spectral density infrasonic background in the range of from 0,5 to 32 Hz). It was shown that among the set of parameters of physical fields present field that can resonate in the functioning of the human organism. The greatest coherence with heart rate variability detect variations eastern component of the geomagnetic field.

  5. A 3-D Computational Study of a Variable Camber Continuous Trailing Edge Flap (VCCTEF) Spanwise Segment

    Science.gov (United States)

    Kaul, Upender K.; Nguyen, Nhan T.

    2015-01-01

    Results of a computational study carried out to explore the effects of various elastomer configurations joining spanwise contiguous Variable Camber Continuous Trailing Edge Flap (VCCTEF) segments are reported here. This research is carried out as a proof-of-concept study that will seek to push the flight envelope in cruise with drag optimization as the objective. The cruise conditions can be well off design such as caused by environmental conditions, maneuvering, etc. To handle these off-design conditions, flap deflection is used so when the flap is deflected in a given direction, the aircraft angle of attack changes accordingly to maintain a given lift. The angle of attack is also a design parameter along with the flap deflection. In a previous 2D study,1 the effect of camber was investigated and the results revealed some insight into the relative merit of various camber settings of the VCCTEF. The present state of the art has not advanced sufficiently to do a full 3-D viscous analysis of the whole NASA Generic Transport Model (GTM) wing with VCCTEF deployed with elastomers. Therefore, this study seeks to explore the local effects of three contiguous flap segments on lift and drag of a model devised here to determine possible trades among various flap deflections to achieve desired lift and drag results. Although this approach is an approximation, it provides new insights into the "local" effects of the relative deflections of the contiguous spanwise flap systems and various elastomer segment configurations. The present study is a natural extension of the 2-D study to assess these local 3-D effects. Design cruise condition at 36,000 feet at free stream Mach number of 0.797 and a mean aerodynamic chord (MAC) based Reynolds number of 30.734x10(exp 6) is simulated for an angle of attack (AoA) range of 0 to 6 deg. In the previous 2-D study, the calculations revealed that the parabolic arc camber (1x2x3) and circular arc camber (VCCTEF222) offered the best L

  6. Performance of the WRF model to simulate the seasonal and interannual variability of hydrometeorological variables in East Africa: a case study for the Tana River basin in Kenya

    Science.gov (United States)

    Kerandi, Noah Misati; Laux, Patrick; Arnault, Joel; Kunstmann, Harald

    2016-08-01

    This study investigates the ability of the regional climate model Weather Research and Forecasting (WRF) in simulating the seasonal and interannual variability of hydrometeorological variables in the Tana River basin (TRB) in Kenya, East Africa. The impact of two different land use classifications, i.e., the Moderate Resolution Imaging Spectroradiometer (MODIS) and the US Geological Survey (USGS) at two horizontal resolutions (50 and 25 km) is investigated. Simulated precipitation and temperature for the period 2011-2014 are compared with Tropical Rainfall Measuring Mission (TRMM), Climate Research Unit (CRU), and station data. The ability of Tropical Rainfall Measuring Mission (TRMM) and Climate Research Unit (CRU) data in reproducing in situ observation in the TRB is analyzed. All considered WRF simulations capture well the annual as well as the interannual and spatial distribution of precipitation in the TRB according to station data and the TRMM estimates. Our results demonstrate that the increase of horizontal resolution from 50 to 25 km, together with the use of the MODIS land use classification, significantly improves the precipitation results. In the case of temperature, spatial patterns and seasonal cycle are well reproduced, although there is a systematic cold bias with respect to both station and CRU data. Our results contribute to the identification of suitable and regionally adapted regional climate models (RCMs) for East Africa.

  7. A Study of Precipitation Climatology and Its Variability over Europe Using an Advanced Regional Model (WRF)

    KAUST Repository

    Dasari, Hari Prasad

    2015-03-06

    In recent years long-term precipitation trends on a regional scale have been given emphasis due to the impacts of global warming on regional hydrology. In this study, regional precipitation trends are simulated over the Europe continent for a 60-year period in 1950-2010 using an advanced regional model, WRF, to study extreme precipitation events over Europe. The model runs continuously for each year during the period at a horizontal resolution of 25 km with initial/ boundary conditions derived from the National Center for Environmental Prediction (NCEP) 2.5 degree reanalysis data sets. The E-OBS 0.25 degree rainfall observation analysis is used for model validation. Results indicate that the model could reproduce the spatial annual rainfall pattern over Europe with low amounts (250 - 750 mm) in Iberian Peninsula, moderate to large amounts (750 - 1500 mm) in central, eastern and northeastern parts of Europe and extremely heavy falls (1500 - 2000 mm) in hilly areas of Alps with a slight overestimation in Alps and underestimation in other parts of Europe. The regional model integrations showed increasing errors (mean absolute errors) and decreasing correlations with increasing time scale (daily to seasonal). Rainfall is simulated relatively better in Iberian Peninsula, northwest and central parts of Europe. A large spatial variability with the highest number of wet days over eastern, central Europe and Alps (~200 days/year) and less number of wet days over Iberian Peninsula (≤150 days/year) is also found in agreement with observations. The model could simulate the spatial rainfall climate variability reasonably well with low rainfall days (1 - 10 mm/days) in almost all zones, heavy rainfall events in western, northern, southeastern hilly and coastal zones and extremely heavy rainfall events in northern coastal zones. An increasing trend of heavy rainfall in central, southern and southeastern parts, a decreasing trend in Iberian Peninsula and a steady trend in other

  8. Heart rate variability during treatment of breakthrough pain in patients with advanced cancer: a pilot study

    Directory of Open Access Journals (Sweden)

    Masel EK

    2016-12-01

    Full Text Available Eva Katharina Masel, Patrick Huber, Tobias Engler, Herbert Hans WatzkeClinical Division of Palliative Care, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria Background: Decisions on the intensity of analgesic therapy and judgments regarding its efficacy are difficult at the end of life, when many patients are not fully conscious and pain is a very common symptom. In healthy individuals and in postoperative settings, nociception and subsequent pain relief have been shown to induce changes in the autonomic nervous system (ANS, which can be detected by measuring heart rate variability (HRV. Objectives: The changes in the ANS were studied by measuring HRV during opioid therapy for cancer breakthrough pain (CBTP in palliative-care patients with cancer and compared these changes with patient-reported pain levels on a numeric rating scale (NRS. Patients and methods: The study included ten patients with advanced cancer and baseline opioid therapy. In each patient, a 24-hour peak-to-peak HRV measurement with a sampling rate of 4,000 Hz was performed. High frequency (HF, low frequency (LF, total power, pNN50 (indicating parasympathetic activity, and log LF/HF were obtained in two intervals prior to therapy and in four intervals thereafter. Intensity of CBTP was recorded using a patient-reported NRS prior to therapy and 30 minutes afterward. Results: CBTP occurred in seven patients (three males and four females; mean age: 62 ± 5.2 years and was treated with opioids. A highly significant positive correlation was found between opioid-induced reduction in patient-reported pain intensity based on NRS and changes in log LF/HF (r > 0.700; p < 0.05. Log LF/HF decreased in patients who had a reduction in pain of >2 points on the NRS but remained unchanged in the other patients. Conclusion: Our data suggest that log LF/HF may be a useful surrogate marker for alleviation of CBTP in patients with advanced cancer and might

  9. Differential variability improves the identification of cancer risk markers in DNA methylation studies profiling precursor cancer lesions.

    Science.gov (United States)

    Teschendorff, Andrew E; Widschwendter, Martin

    2012-06-01

    The standard paradigm in omic disciplines has been to identify biologically relevant biomarkers using statistics that reflect differences in mean levels of a molecular quantity such as mRNA expression or DNA methylation. Recently, however, it has been proposed that differential epigenetic variability may mark genes that contribute to the risk of complex genetic diseases like cancer and that identification of risk and early detection markers may therefore benefit from statistics based on differential variability. Using four genome-wide DNA methylation datasets totalling 311 epithelial samples and encompassing all stages of cervical carcinogenesis, we here formally demonstrate that differential variability, as a criterion for selecting DNA methylation features, can identify cancer risk markers more reliably than statistics based on differences in mean methylation. We show that differential variability selects features with heterogeneous outlier methylation profiles and that these play a key role in the early stages of carcinogenesis. Moreover, differentially variable features identified in precursor non-invasive lesions exhibit significantly increased enrichment for developmental genes compared with differentially methylated sites. Conversely, differential variability does not add predictive value in cancer studies profiling invasive tumours or whole-blood tissue. Finally, we incorporate the differential variability feature selection step into a novel adaptive index prediction algorithm called EVORA (epigenetic variable outliers for risk prediction analysis), and demonstrate that EVORA compares favourably to powerful prediction algorithms based on differential methylation statistics. Statistics based on differential variability improve the detection of cancer risk markers in the context of DNA methylation studies profiling epithelial preinvasive neoplasias. We present a novel algorithm (EVORA) which could be used for prediction and diagnosis of precursor epithelial

  10. Maxillomandibular Advancement in Obstructive Sleep Apnea Syndrome Patients: a Restrospective Study on the Sagittal Cephalometric Variables

    Directory of Open Access Journals (Sweden)

    Paolo Ronchi

    2013-06-01

    Full Text Available Objectives: The present retrospective study analyzes sagittal cephalometric changes in patients affected by obstructive sleep apnea syndrome submitted to maxillomandubular advancement. Material and Methods: 15 adult sleep apnea syndrome (OSAS patients diagnosed by polysomnography (PSG and treated with maxillomandubular advancement (MMA were included in this study. Pre- (T1 and postsurgical (T2 PSG studies assessing the apnea/hypopnea index (AHI and the lowest oxygen saturation (LSAT level were compared. Lateral cephalometric radiographs at T1 and T2 measuring sagittal cephalometric variables (SNA, SNB, and ANB were analyzed, as were the amount of maxillary and mandibular advancement (Co-A and Co-Pog, the distance from the mandibular plane to the most anterior point of the hyoid bone (Mp-H, and the posterior airway space (PAS.Results: Postoperatively, the overall mean AHI dropped from 58.7 ± 16 to 8.1 ± 7.8 events per hour (P < 0.001. The mean preoperative LSAT increased from 71% preoperatively to 90% after surgery (P < 0.001. All the patients in our study were successfully treated (AHI < 20 or reduced by 50%. Cephalometric analysis performed after surgery showed a statistically significant correlation between the mean SNA variation and the decrease in the AHI (P = 0.01. The overall mean SNA increase was 6°.Conclusions: Our findings suggest that the improvement observed in the respiratory symptoms, namely the apnea/hypopnea episodes, is correlated with the SNA increase after surgery. This finding may help maxillofacial surgeons to establish selective criteria for the surgical approach to sleep apnea syndrome patients.

  11. Study of variables affecting critical value notification in a laboratory catering to tertiary care hospital.

    Science.gov (United States)

    Agarwal, Rachna; Chhillar, Neelam; Tripathi, Chandra B

    2015-01-01

    During post-analytical phase, critical value notification to responsible caregiver in a timely manner has potential to improve patient safety which requires cooperative efforts between laboratory personnel and caregivers. It is widely accepted by hospital accreditors that ineffective notification can lead to diagnostic errors that potentially harm patients and are preventable. The objective of the study was to assess the variables affecting critical value notification, their role in affecting it's quality and approaches to improve it. In the present study 1,187 critical values were analysed in the Clinical Chemistry Laboratory catering to tertiary care hospital for neuropsychiatric diseases. During 25 months of study period, we evaluated critical value notification with respect to clinical care area, caregiver to whom it was notified and timeliness of notification. During the study period (25 months), the laboratory obtained 1,279 critical values in clinical chemistry. The analytes most commonly notified were sodium and potassium (20.97 & 20.8 % of total critical results). Analysis of critical value notification versus area of care showed that critical value notification was high in ICU and emergency area followed by inpatients and 64.61 % critical values were notified between 30 and 120 min after receiving the samples. It was found that failure to notify the responsible caregiver in timely manner represent an important patient safety issue and may lead to diagnostic errors. The major area of concern are notification of critical value for outpatient samples, incompleteness of test requisition forms regarding illegible writing, lack of information of treating physician and location of test ordering and difficulty in contacting the responsible caregiver.

  12. Overnight heart rate variability in patients with obstructive sleep apnoea: a time and frequency domain study.

    Science.gov (United States)

    Zhu, Kaixian; Chemla, Denis; Roisman, Gabriel; Mao, Wenyuan; Bazizi, Samir; Lefevre, Amaury; Escourrou, Pierre

    2012-11-01

    Heightened sympathetic activity plays a role in the cardiovascular sequelae of obstructive sleep apnoea (OSA). Cardiac autonomic function may be assessed non-invasively by studying heart rate variability (HRV). The aim of the present study was to compare overnight HRV between a control group and a group of subjects with severe OSA. The potential confounding effects of age, sex, baseline autonomic status and sleep stage distribution were taken into account. Our prospective Holter study compared overnight (0030-0530 hours) HRV in 23 controls (apnoea hypopnoea index (AHI) = 5 ± 3 /h) and 23 subjects with severe OSA (AHI = 65 ± 23 /h), matched for age and sex and with a similar percentage of rapid eye movement sleep. The mean normal-to-normal RR interval (NN) was shorter in the OSA compared with control group (903 vs 1039 ms, respectively), whereas the other time-domain indices of HRV, as well as the classic frequency-domain indices, were similar. Essentially similar results were obtained hourly and when only subjects with high mean values of the standard deviation of all NN (≥ 90 ms) were evaluated. In the 0.01-0.06 Hz range corresponding to the typical OSA pattern of bradycardia-tachycardia termed cyclic variation of heart rate (CVHR), higher power was documented hourly in OSA, with a significant correlation between overnight power and both AHI and mean oxyhaemoglobin saturation. The percentage of NN > x ms different from the previous one (pNNx family) had no diagnostic value. The results of the present study suggest that NN may be the best index to quantify the overnight sympathovagal balance in OSA and that a spectral band overlapping the apnoea-related pattern of CVHR slightly improved the characterization of the apnoea-related HRV patterns.

  13. Analysis of heart rate variability in pre-eclamptic pregnancy: a study employing frequency domain analysis

    Directory of Open Access Journals (Sweden)

    Gul Ar Navi Khan

    2014-08-01

    Full Text Available Background: Preeclampsia is a disorder characterized by development of hypertension to the extent of 140/90 mmHg or more with proteinuria after 20th weeks of pregnancy in a previously normotensive and non proteinuric woman. Physiologically blood pressure is controlled by Autonomic Nervous System (ANS so study of ANS during pregnancy plays a significant role to extract some vital information which may be helpful to deal with Pregnancy Induced Hypertension (PIH or preeclampsia. The autonomic nervous system and changes in ANS during different pathophysiological conditions could be evaluated with heart rate variability analysis test. The modification in the autonomic control occurs during pregnancy and its evaluation through Heart Rate Variability (HRV analysis is very informative technique now a day but studied little thus the main objective of our project is to compare the maternal HRV changes between normal pregnancy and pre-eclamptic pregnancy. Methods: 48 subjects (33 of normotensive pregnant women i.e., control group and 15 pre-eclamptic pregnant women i.e, study group of more than 20 weeks pregnancy were recruited from the outpatients, antenatal unit and wards of obstetrics and gynaecology department of JNMC, AMU, Aligarh. Physical examination was done and anthropometric measurement like height and weight were taken. BMI was calculated as per Quetlet's index. Urine test was conducted to every pregnant woman for urine albumin and we designated the pregnant women as pre-eclamptic women on the basis of definition. The subject was advised to take complete bed rest in supine position for 15 minutes in a cool and calm environment. The recording of short term HRV was done according to recommendation of the task force on HRV. The data was transferred from Medicaid machine to window based computer with HRV analysis software. Frequency domain analysis of HRV was taken for further statistical analysis. Results: There was no significant difference of

  14. Studies on influence of process variables on performance of gliclazide mucoadhesive microcapsules

    Directory of Open Access Journals (Sweden)

    Bala Vishnu Priya Mukkala

    2011-01-01

    Full Text Available Microencapsulation is a unique technique of controlled drug delivery system and is of major importance for effective alteration of drug release required to produce a novel formulation with desired characteristics to overcome the disadvantages of the conventional therapeutic dosage forms. Microcapsules offer efficient absorption and enhanced bioavailability owing to their higher surface area, however, mucoadhesive microcapsules render more intimate contact with the mucus membrane thereby leading to increase in the gastro intestinal residence time. Gliclazide is an oral hypoglycemic second generation sulfonyl urea, which is useful for a long-term treatment of non-insulin dependent diabetes mellitus. In the present investigation, the gliclazide microcapsules are formulated to control the release rate and improve the absorption across gastrointestinal membrane by employing ionic gelation method. The effect of various process variables such as curing time, stirring speed, stirring time, volume and concentration of curing reagent on entrapment efficiency, and drug release rate was studied. The microcapsules were evaluated for drug content, encapsulation efficiency, in vitro drug release studies. The optimized formulation was selected based on the entrapment efficiency and drug release rate. The optimized formulation of gliclazide microcapsules were evaluated for rheological properties, moisture content, swelling index, erosion studies, wall thickness and in vitro wash off test. The microcapsules formulated with 2:1 coat:core ratio by using 150 ml of 0.1M Cacl2 solution as curing reagent, at a stirring speed of 400 rpm for 60 minutes and a curing period of 48 hrs were found to be the optimum formulation. The drug release followed zero order kinetics and was controlled by peppas mechanism. The pharmacodynamic activity of optimized gliclazide microcapsules was conducted by measuring blood glucose levels in healthy albino rabbits. The percentage glucose

  15. Estimating search engine index size variability: a 9-year longitudinal study.

    Science.gov (United States)

    van den Bosch, Antal; Bogers, Toine; de Kunder, Maurice

    One of the determining factors of the quality of Web search engines is the size of their index. In addition to its influence on search result quality, the size of the indexed Web can also tell us something about which parts of the WWW are directly accessible to the everyday user. We propose a novel method of estimating the size of a Web search engine's index by extrapolating from document frequencies of words observed in a large static corpus of Web pages. In addition, we provide a unique longitudinal perspective on the size of Google and Bing's indices over a nine-year period, from March 2006 until January 2015. We find that index size estimates of these two search engines tend to vary dramatically over time, with Google generally possessing a larger index than Bing. This result raises doubts about the reliability of previous one-off estimates of the size of the indexed Web. We find that much, if not all of this variability can be explained by changes in the indexing and ranking infrastructure of Google and Bing. This casts further doubt on whether Web search engines can be used reliably for cross-sectional webometric studies.

  16. Biotic and abiotic variables influencing plant litter breakdown in streams: a global study

    Science.gov (United States)

    Pearson, Richard G.; Hui, Cang; Gessner, Mark O.; Pérez, Javier; Alexandrou, Markos A.; Graça, Manuel A. S.; Cardinale, Bradley J.; Albariño, Ricardo J.; Arunachalam, Muthukumarasamy; Barmuta, Leon A.; Boulton, Andrew J.; Bruder, Andreas; Callisto, Marcos; Chauvet, Eric; Death, Russell G.; Dudgeon, David; Encalada, Andrea C.; Ferreira, Verónica; Figueroa, Ricardo; Flecker, Alexander S.; Gonçalves, José F.; Helson, Julie; Iwata, Tomoya; Jinggut, Tajang; Mathooko, Jude; Mathuriau, Catherine; M'Erimba, Charles; Moretti, Marcelo S.; Pringle, Catherine M.; Ramírez, Alonso; Ratnarajah, Lavenia; Rincon, José; Yule, Catherine M.

    2016-01-01

    Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (Alnus glutinosa) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons. PMID:27122551

  17. Physiological Study on the Relation of Heart Rate Variability in Ageing and Thyroid Hormone Disorder

    Directory of Open Access Journals (Sweden)

    Elsayed A. M. Shokr

    2016-04-01

    Full Text Available The present study aimed to investigate whether cardiac autonomic dysfunction in aging human might be related to an underlying thyroid disturbance. ageing has been associated with hypothyroidism and cardiac autonomic dysfunction. On the basis of body mass index (BMI, 150 patients were grouped into three groups (n = 50 48 years ± 2, 55 years ± 2 and 63 years ± 2. Electrocardiogram was recorded using PowerLab system and the time and frequency domain measures of heart rate variability (HRV were calculated. Fasting blood samples were drawn for measurement of serum thyroid stimulating hormone (TSH, total thyroxin (T4 and total triiodothyronine (T3 concentrations. The levels of TSH, T4 and T3 were not significantly different between the groups. The frequency domain HRV parameter reflecting parasympathetic tone (high-frequency normalized units, HFnu was significantly reduced in aging third groups group. The parameters which reflect sympathetic activation (Heart rate, low-frequency normalized units; LFnu and the LF/HF ratio were significantly increased in the aging group. HFnu was significantly and negatively correlated with age, whereas LFnu and LF/HF ratio were significantly and positively correlated with the above mentioned parameters. No significant relationships were noted between the HRV parameters and the levels of TSH or thyroid hormones. Cardiac autonomic dysfunction in aging human is not linked with underlying thyroid disturbance.

  18. Comparative Study of Controllers for a Variable Area MIMO Interacting NonLinear System

    Directory of Open Access Journals (Sweden)

    Priya Chandrasekar

    2014-03-01

    Full Text Available Most of the industrial processes are basically Multi Input Multi Output (MIMO system. In this paper a new combination of Spherical Conical Interacting Tank System (SCITS which is a variable area nonlinear MIMO system is considered for study and various control algorithms based on Ziegler Nichol’s tuning method, Hagglund Astrom Robust tuning method, Fractional Order (FO control and Passivity Based Control (PBC are used and compared for the level control of spherical tank system and conical tank system connected with interaction. Transfer function matrix of the system is obtained experimentally from the open loop response of the system. The designed controllers are tested for servo and regulatory operations. The controllers are compared in terms of time domain specification and performance index criterion. From the analysis of the simulation results, it is seen that FO controller gives improved performance when compared to conventional Integer Order (IO controller and overall Passivity Based Controller (PBCr gives improved performance comparatively for spherical conical interacting MIMO system.

  19. Biotic and abiotic variables influencing plant litter breakdown in streams: a global study.

    Science.gov (United States)

    Boyero, Luz; Pearson, Richard G; Hui, Cang; Gessner, Mark O; Pérez, Javier; Alexandrou, Markos A; Graça, Manuel A S; Cardinale, Bradley J; Albariño, Ricardo J; Arunachalam, Muthukumarasamy; Barmuta, Leon A; Boulton, Andrew J; Bruder, Andreas; Callisto, Marcos; Chauvet, Eric; Death, Russell G; Dudgeon, David; Encalada, Andrea C; Ferreira, Verónica; Figueroa, Ricardo; Flecker, Alexander S; Gonçalves, José F; Helson, Julie; Iwata, Tomoya; Jinggut, Tajang; Mathooko, Jude; Mathuriau, Catherine; M'Erimba, Charles; Moretti, Marcelo S; Pringle, Catherine M; Ramírez, Alonso; Ratnarajah, Lavenia; Rincon, José; Yule, Catherine M

    2016-04-27

    Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (Alnus glutinosa) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons.

  20. Automatic detection of overnight deep sleep based on heart rate variability: a preliminary study.

    Science.gov (United States)

    Long, Xi; Fonseca, Pedro; Haakma, Reinder; Foussier, Jérôme; Aarts, Ronald M

    2014-01-01

    This preliminary study investigated the use of cardiac information or more specifically, heart rate variability (HRV), for automatic deep sleep detection throughout the night. The HRV data can be derived from cardiac signals, which were obtained from polysomnography (PSG) recordings. In total 42 features were extracted from the HRV data of 15 single-night PSG recordings (from 15 healthy subjects) for each 30-s epoch, used to perform epoch-by-epoch classification of deep sleep and non-deep sleep (including wake state and all the other sleep stages except deep sleep). To reduce variation of cardiac physiology between subjects, we normalized each feature per subject using a simple Z-score normalization method by subtracting the mean and dividing by the standard deviation of the feature values. A correlation-based feature selection (CFS) method was employed to select informative features as well as removing feature redundancy and a linear discriminant (LD) classifier was applied for deep and non-deep sleep classification. Results show that the use of Z-score normalization can significantly improve the classification performance. A Cohen's Kappa coefficient of 0.42 and an overall accuracy of 81.3% based on a leave-one-subject-out cross-validation were achieved.

  1. Evaluating the Potential of Variable Renewable Energy for a Balanced Isolated Grid: A Japanese Case Study

    Directory of Open Access Journals (Sweden)

    Mai Inoue

    2017-01-01

    Full Text Available There is a global push to develop renewable energy to further a low-carbon society. However, the nature of variable renewable energy (VRE sources such as wind power and solar photovoltaic (PV systems may create problems because electricity grids require a stable power supply to match demand. To evaluate the potential capacity of VREs that may be installed, we develop an optimized model that balances power supply and demand and also considers grid balancing by battery storage and load frequency control. The model was applied to a case study of an isolated grid on a remote Japanese island. When set to optimize the grid in terms of lowest cost, the model suggested that, compared with the base case, the capacity of wind power should be increased by a factor of 1.7 and 15.8 for situations without and with battery storage, respectively. Since it was always considered to be more expensive than wind power, no change in solar PV capacity was observed. These approaches resulted in a decrease in the total power generation cost of 2% and 24%, respectively, while total CO2 emissions fell by 3% and 52%, primarily driven by decreased used of the existing fossil-fueled thermal plant.

  2. Cephalometric landmark variability among orthodontists and dentomaxillofacial radiologists: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Durao, Ana Paula Reis; Ferreira, Afonso P. [Dept.of Faculty of Dental Medicine, University of Porto, Porto (Portugal); Morosolli, Aline [Dept.of Surgery, Dentistry School, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul (Brazil); Pittayapat, Pisha [Dept.of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok (Thailand); Bolstad, Napat [Dept.of Clinical Dentistry, Faculty of Health Science, UiT The Arctic University of Norway, Tromso (Norway); Jacobs, Reinhilde [Dept.of Oral Imaging Center, OMFS-IMPATH Research Group, Dept. of Imaging and Pathology, Faculty of Medicine, University of Leuven, Leuven (Belgium)

    2015-12-15

    The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks. Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for each landmark was considered the best estimate and used as the standard. Variation in measurements of the distance between landmarks and measurements of the angles associated with certain landmarks was also assessed by a subset of two observers, and intraobserver and interobserver agreement were evaluated. Intraclass correlation coefficients were excellent for intraobserver agreement, but only good for interobserver agreement. The least reliable landmark for orthodontists was the gnathion (Gn) point (standard deviation [SD], 5.92 mm), while the orbitale (Or) was the least reliable landmark (SD, 4.41 mm) for dentomaxillofacial radiologists. Furthermore, the condylion (Co)-Gn plane was the least consistent (SD, 4.43 mm). We established that some landmarks were not as reproducible as others, both horizontally and vertically. The most consistently identified landmark in both groups was the lower incisor border, while the least reliable points were Co, Gn, Or, and the anterior nasal spine. Overall, a lower level of reproducibility in the identification of cephalometric landmarks was observed among orthodontists.

  3. A model study of the Gulf Stream Extension intrinsic low-frequency variability

    Science.gov (United States)

    Quattrocchi, Giovanni; Pierini, Stefano; Dijkstra, Henk A.

    2010-05-01

    A process-oriented model study aimed at understanding aspects of the intrinsic low-frequency variability of the Gulf Stream Extension is presented. Reduced-gravity and two-layer shallow water eddy-permitting models are implemented in a domain spanning the latitudes from 10°S to 60°N, with schematic coastlines representing correctly the large-scale shape of the continental boundaries. The forcing, provided by a time-independent climatological wind stress field, is obtained from 41 years (1961-2001) of ECMWF Re-Analysis data. In the two-layer model a Deep Western Boundary Current is introduced through boundary forcing. The dissipative mechanisms are the lateral eddy viscosity (with coefficient A) and the interfacial friction (with coefficient F) and, in the two-layer model, also the bottom friction. Sensitivity experiments are carried out by varying A and F, and the results are interpreted also in terms of dynamical systems theory. For sufficiently high dissipation a steady western boundary current and corresponding extension jet are obtained: their comparison with AVISO altimeter data provides experimental validation of the model setup. Decreasing A and F leads to a first Hopf bifurcation and to the successive transition to chaotic fluctuations characterized by interannual time scales. A thorough analysis is carried out also by considering previous work on more idealized double-gyre flows.

  4. Association between mortality and blood pressure variability in hypertensive and normotensive elders: A cohort study.

    Science.gov (United States)

    Weiss, Avraham; Beloosesky, Yichayaou; Koren-Morag, Nira; Grossman, Alon

    2017-08-01

    To evaluate the association between blood pressure variability (BPV) and mortality in the elderly, all blood pressure measurements recorded in a cohort of individuals 65 years and older were collected and the association between BPV coefficient of variation (BPV divided by mean arterial pressure) was calculated. Mortality during a 10-year period was compared between BPV coefficient of variation quartiles. Overall, 39 502 individuals 65 years and older were included in the analysis, of which 31 737 (80.3%) were hypertensive; 12 817 (32.4%) individuals died during the study period. Mortality was lower in the second and third blood pressure quartiles compared with the first quartile in both the normotensive and hypertensive groups. In both normotensive and hypertensive individuals, mortality was higher in the fourth quartile, but it was more pronounced in normotensive individuals (odds ratio, 1.18; 95% confidence interval, 1.06-1.31 in hypertensive individuals vs odds ratio, 1.27; 95% confidence interval, 1.17-1.37 in normotensive individuals). High and low BPV are associated with mortality in both hypertensive and normotensive elders. ©2017 Wiley Periodicals, Inc.

  5. Molecular Simulation Study of Montmorillonite in Contact with Variably Wet Supercritical Carbon Dioxide

    KAUST Repository

    Kadoura, Ahmad Salim

    2017-03-07

    We perform grand canonical Monte Carlo simulations to study the detailed molecular mechanism of intercalation behavior of CO2 in Na-, Ca-, and Mg- montmorillonite exposed to variably hydrated supercritical CO2 at 323.15 K and 90 bar, The simulations indicate that the intercalation of CO2 strongly depends on the relative humidity (RH). The intercalation of CO2 in the dehydrated interlayer is inhibited, followed by the swelling of the interlayer region due to uptake of water and CO2 as the RH increases. In all of the hydrated clay samples, the amount of the intercalated CO2 generally decreases as a function of increasing RH, which is attributed mainly to the weakening of the interaction between CO2 and clay. At low RH values, Ca- and Mg- montmorillonite are relatively more efficient in capturing CO2. The amount of CO2 trapped in all clay samples shows similar values above RH of similar to 60%. Molecular dynamics simulations show that the diffusion coefficient of each species generally increases with increasing RH due to the associated expansion of the interlayer distance of the clay. For all the hydrated samples, the diffusion coefficients of CO2 and water in the interlayers are mostly comparable due to the fact that CO2 molecules are well solvated. The diffusion of CO2 in each hydration state is mostly independent of the type of cation in accordance with the fact that CO2 molecules hardly migrate into the first hydration shell of the interlayer cations.

  6. Variables related to working capability among Swiss patients with multiple sclerosis--a cohort study.

    Directory of Open Access Journals (Sweden)

    Oliver Findling

    Full Text Available Reduced working capability is one of the most devastating consequences of multiple sclerosis (MS. We aimed to study working capability and related variables in Swiss MS patients.A cross-sectional analysis of employment status and risk factors for reduced working capability among MS patients treated at our outpatient clinic. A questionnaire was mailed to 644 MS patients and returned by 69.7%. 405 patients (66% female, mean age 44.2 years (SD ± 10.2, median EDSS 3.0 (SD ± 1.8 were eligible for subsequent analysis.After a mean disease duration of 12.3 years (SD ± 8.25, full or part time employment was declared by 26.7% and 25.7%, respectively. Incapacity to work was reported by 27.1%. A total of 52.8% specified MS as the cause for altered working capability, whereas 20.5% cited reasons unrelated to the disorder. Even with minimal disability (EDSS < 3 a significant proportion of patients (24% reported reduced working capability. Among the MS-specific restricting factors were fatigue (47.6%, sensorimotor deficits (31.1%, impaired vision (3.3% and pain (2.8%.MS continues to takes its toll on the professional life of the patients early in the course. While complete incapacity becomes relevant with moderate to severe disability, many patients scale down to part-time even with minimal impairment.

  7. Mid-infrared study of the molecular structure variability of insoluble organic matter from primitive chondrites

    Science.gov (United States)

    Orthous-Daunay, F.-R.; Quirico, E.; Beck, P.; Brissaud, O.; Dartois, E.; Pino, T.; Schmitt, B.

    2013-03-01

    Insoluble Organic Matter (IOM) found in primitive meteorites was formed in the Early Solar System and subsequently processed on the parent asteroids. The location, temporal sequence and processes of formation of this IOM are still a matter of debate. In particular, there is no consensus on the actual effect of post-accretional aqueous alteration processes on the chemical composition and structure of IOM. In the most primitive chondrites (types 1 and 2), these alterations have so far been either neglected or generically assigned to oxidation processes induced by fluid circulation. A series of IOM samples extracted from 14 chondrites with extensively documented post-accretional histories have been studied by infrared spectroscopy. Aqueous alteration shows no detectable effect on the chemical composition and structure of IOM within or across chondrite classes. Indeed, the most effective post-accretional process appears to be a high-temperature short-duration heating event and concerns essentially type 2 chondrites. In any case, post-accretional processes cannot account for all the chemical and structural variations of IOM. Chondrites from the CI, CR and CM classes accreted IOM precursors with moderately variable compositions, suggesting a chemical heterogeneity of the protosolar disk. The 3.4 μm band, and possibly its overtones and combinations in the near-infrared range, appear to be tracer(s) of the chemical class and possibly of surface heating processes triggered by impacts.

  8. Influence of Natural Honey on Biochemical and Hematological Variables in AIDS: A case study

    Directory of Open Access Journals (Sweden)

    Noori S. Al-Waili

    2006-01-01

    Full Text Available Honey lowers prostaglandins and elevates nitric oxide (NO in various biological fluids in normal persons. NO and prostaglandin play a role in pathogenesis of AIDS. The study was designed to assess the effect of natural honey on prostaglandins and NO levels, blood indices and biochemical tests in a 40 year-old woman with AIDS. This presentation is a case story of a 40 year-old women with a long history of AIDS treated with 80g of natural honey. Plasma and urinary prostaglandin F2 alpha and thromboxane B2 levels, plasma, urine and saliva content of NO-end product (total nitrite and hematological tests were estimated before and 3 hours after oral consumption of 80g of natural honey. These variables, in addition to biochemical tests, were re-estimated after 21 days of daily consumption of 80g of natural honey. Results showed that prostaglandins level compared with normal subjects were elevated in patient with AIDS. Natural honey decreased prostaglandins levels, and elevated NO-end product, percentage of lymphocytes, platelet count, and serum protein, albumin and copper levels. It might be concluded that natural honey decreased prostaglandins level, elevated NO production and improved hematological and biochemical tests in a patient with a long history of AIDS.

  9. Using climate response functions in analyzing electricity production variables. A case study from Norway.

    Science.gov (United States)

    Tøfte, Lena S.; Martino, Sara; Mo, Birger

    2016-04-01

    This study analyses whether and to which extent today's hydropower system and reservoirs in Mid-Norway are able to balance new intermittent energy sources in the region, in both today's and tomorrow's climate. We also investigate if the electricity marked model EMPS gives us reasonable results also when run in a multi simulation mode without recalibration. Climate related energy (CRE) is influenced by the weather, the system for energy production and transport, and by market mechanisms. In the region of Mid-Norway, nearly all power demand is generated by hydro-electric facilities. Due to energy deficiency and limitations in the power grid the region experiences a deficit of electricity. The region is likely to experience considerable investments in wind power and small-scale hydropower and the transmission grid within and out of the region will probably be extended, so this situation might change. In addition climate change scenarios for the region agree on higher temperatures, more precipitation in total and a larger portion of the precipitation coming as rain instead of snow, as well as we expect slightly higher wind speed and more storms during the winter. Changing temperatures will also change the electricity demand. EMPS is a tool for forecasting and planning in electricity markets, developed for optimization and simulation of hydrothermal power systems with a considerable share of hydro power. It takes into account transport constraints and hydrological differences between major areas or regional subsystems. During optimization the objective is to minimize the expected cost in the whole system subject to all constraints. Incremental water values (marginal costs for hydropower) are computed for each area using stochastic dynamic programming. A heuristic approach is used to treat the interaction between areas. In the simulation part of the model total system costs are minimized week by week for each climate scenario in a linear problem formulation. A detailed

  10. Pilot study employing heart rate variability biofeedback training to decrease anxiety in patients with eating disorders

    National Research Council Canada - National Science Library

    Scolnick, Barbara; Mostofsky, David I; Keane, Robert J

    2014-01-01

    Heart rate variability (HRV) biofeedback, a technique which encourages slow meditative breathing, was offered to 25 in-patients with various eating disorder diagnoses-anorexia nervosa, bulimia nervosa and binge eating disorder...

  11. Liaison of Exchange Rate and Macroeconomic Variables: A Case Study of Pakistan

    Directory of Open Access Journals (Sweden)

    Aneel Salman

    2015-12-01

    Full Text Available Exchange rate plays a significant role in the economic growth of a country because it has also a close relationship to some major macroeconomic variables like Gross Domestic Product (GDP, interest rate, current account and inflation etc. All these variables are adversely affected by uncertainty or fluctuations in exchange rate. The objective of this paper was to find out the relationship between the exchange rate and other above mentioned macroeconomic variables. The paper not only described the relationship but also defined the nature of the relationship between the selected variables. The results showed that exchange rate has a long run relationship to GDP, inflation, interest rate and current account. Granger Causality test concluded that there was unidirectional causal relationship between exchange rate and GDP and the direction of causal relationship run from exchange rate to GDP. There were also some policy implications suggested for the stability in exchange rate and removing the adverse effects of uncertainty in Pakistan.

  12. STUDY ON PARAMETERS FOR TOPOLOGICAL VARIABLES FIELD INTERPOLATED BY MOVING LEAST SQUARE APPROXIMATION

    Institute of Scientific and Technical Information of China (English)

    Kal Long; Zhengxing Zuo; Rehan H.Zuberi

    2009-01-01

    This paper presents a new approach to the structural topology optimization of con-tinuum structures. Material-point independent variables are presented to illustrate the existence condition, or inexistence of the material points and their vicinity instead of elements or nodes in popular topology optimization methods. Topological variables field is constructed by moving least square approximation which is used as a shape function in the meshless method. Combined with finite element analyses, not only checkerboard patterns and mesh-dependence phenomena are overcome by this continuous and smooth topological variables field, but also the locations and numbers of topological variables can be arbitrary. Parameters including the number of quadrature points, scaling parameter, weight function and so on upon optimum topological configurations are discussed. Two classic topology optimization problems are solved successfully by the pro-posed method. The method is found robust and no numerical instabilities are found with proper parameters.

  13. A Comparative Study of Reduced-Variables-Based Flash and Conventional Flash

    DEFF Research Database (Denmark)

    Yan, Wei; Stenby, Erling Halfdan; Michelsen, Michael Locht

    2013-01-01

    the advantages of the reduced-variables methods in their recent paper. A fair comparison between the reduced-variables-based flash and the conventional flash is not straightforward because it is difficult to formulate the former as unconstrained minimization problems, and the flash calculation time is also...... related to the implementation quality. With the recent formulations by Nichita and Graciaa (2011), it is possible to code the reduced-variables methods without extensive modifications of Michelsen's conventional flash algorithm. A minimization-based reduced-variables algorithm was coded and compared...... with the conventional minimization-based flash. A test with the use of the SPE 3 example (Kenyon and Behie 1987) showed that the best reduction in time was less than 20% for the extreme situation of 25 components and just one row/column with nonzero BIPs. A better performance can be achieved by a simpler implementation...

  14. WASTE SOLIDIFICATION BUILDING BENCH SCALE HIGH ACTIVITY WASTE SIMULANT VARIABILITY STUDY FY2008

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E; Timothy Jones, T; Tommy Edwards, T; Alex Cozzi, A

    2009-03-20

    The primary objective of this task was to perform a variability study of the high activity waste (HAW) acidic feed to determine the impact of feed variability on the quality of the final grout and on the mixability of the salt solution into the dry powders. The HAW acidic feeds were processed through the neutralization/pH process, targeting a final pH of 12. These fluids were then blended with the dry materials to make the final waste forms. A secondary objective was to determine if elemental substitution for cost prohibitive or toxic elements in the simulant affects the mixing response, thus providing a more economical simulant for use in full scale tests. Though not an objective, the HAW simulant used in the full scale tests was also tested and compared to the results from this task. A statistically designed test matrix was developed based on the maximum molarity inputs used to make the acidic solutions. The maximum molarity inputs were: 7.39 HNO{sub 3}, 0.11618 gallium, 0.5423 silver, and 1.1032 'other' metals based on their NO{sub 3}{sup -} contribution. Substitution of the elements aluminum for gallium and copper for silver was also considered in this test matrix, resulting in a total of 40 tests. During the NaOH addition, the neutralization/pH adjustment process was controlled to a maximum temperature of 60 C. The neutralized/pH adjusted simulants were blended with Portland cement and zircon flour at a water to cement mass ratio of 0.30. The mass ratio of zircon flour to Portland cement was 1/12. The grout was made using a Hobart N-50 mixer running at low speed for two minutes to incorporate and properly wet the dry solids with liquid and at medium speed for five minutes for mixing. The resulting fresh grout was measured for three consecutive yield stress measurements. The cured grout was measured for set, bleed, and density. Given the conditions of preparing the grout in this task, all of the grouts were visually well mixed prior to preparing the

  15. Application of the variability-size relationship to atmospheric aerosol studies: estimating aerosol lifetimes and ages

    Directory of Open Access Journals (Sweden)

    J. Williams

    2002-01-01

    Full Text Available Aerosol variability is examined as function of particle size for data collected over the Northern Indian Ocean in February 1999 as part of the INDOEX experiment. It was found that for particles believed to be of terrestrial or oceanic origin, the variability correlated with the average number concentration. For particles that are thought to be formed and grow in the atmosphere through coagulation and condensation an anticorrelation was observed, the minimum in variability coinciding with the maximum in the number concentration. Three altitude ranges were examined (0--1, 4--8 and 8--13 km and the minimum in variability was found to occur at lower particle sizes in the free troposphere (0.065 mm than in the boundary layer (0.165 mm. The observed variability has been compared to that generated by a numerical model in order to determine the relative importance of the physical processes. Modelled variability of 0.02 mm particles caused by nucleation was not observed in the measurements. A previously derived empirical relationship for aerosol residence time was compared with the measured variability as a function of bin size. The aerosol variability / residence time relationship was characterised by a coefficient (b at all altitudes and for both correlating and anticorrelating regimes. By combining the derived coefficient with the model predicted lifetime for 0.020 mm particles we estimated residence times and ages as a function of particle size and altitude. General agreement was found with previous estimates of aerosol residence time. In the upper atmosphere aerosols of 0.065 mm in size have residence times of approximately 1 month and can be transported on a hemispheric scale. The same size aerosol has a lifetime one order of magnitude less in the boundary layer and therefore will not be transported far from the source regions.

  16. An experimental study on the sound and frequency of the Chinese ancient variable bell

    Energy Technology Data Exchange (ETDEWEB)

    Chen Dongsheng; Hu Haining; Xing Lirong; Liu Yongsheng [Department of Maths and Physics, Shanghai University of Electric Power, 200090 Shanghai (China)], E-mail: cds781@hotmail.com

    2009-05-15

    This paper describes an interesting sound phenomenon from a modern copy of the Chinese ancient variable bell which can emit distinctly different sounds at different temperatures. By means of audition-spectrum analyser software-and PC, the sound signals of the variable bell are collected and the fundamental spectra are shown on the PC. The configuration is simple and cheap, suitable for demonstration and laboratory exercises.

  17. [Bibliometric analysis of IBERPOC and EPI-SCAN studies. Contribution of the smoking variable on the iberpoc study].

    Science.gov (United States)

    de Granda-Orive, J I; Alonso-Arroyo, A; López-Padilla, D; Segrelles-Calvo, G; Jiménez-Ruiz, C A; Solano-Reina, S

    2017-02-09

    The aim of this study was to perform a bibliometric analysis of EPI-SCAN and IBERPOC studies using the Science Citation Index and Scopus databases, and to determine the overall impact with the impact of smoking on IBERPOC as a secondary objective. A general searching was conducted in Science Citation Index-Expanded through the Web of Science (WoS) (Thomson Reuters) platform and Scopus on 23 March 2015. The search strategy included the terms "iberpoc" OR "episcan" was performed on 15 October 2015. A total of 24 publications were obtained; 13 from IBERPOC study (9 on "COPD" and 4 for "tobacco"), with 11 from the EPI-SCAN (All COPD) study. A total of 841 WoS citations were obtained (445 IBERPOC [99 of tobacco]), and 1,442 from Scopus (963 IBERPOC [144 tobacco]). The theme "tobacco" contributed with 22.24% and 14.95% of total citations in WoS and Scopus, respectively to the IBERPOC study. It was found that Scopus citations were newer, and a similar impact from both WoS studies was detected, although the IBERPOC impact was greater in Scopus. Collaborative networks of institutions and authors of both studies were identified. There is an important productivity and impact of both studies. Scopus citations are newer than those in WoS. The "tobacco" variable added IBERPOC impact and visibility. There was high density, accessibility, and cohesion in collaborative networks of both studies. Copyright © 2017 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Supply Chain Cooperation by Agreed Reduction of Behavior Variability: A Simulation-based Study

    Directory of Open Access Journals (Sweden)

    M. L. Chew Hernandez

    2017-04-01

    Full Text Available Supply chain echelons normally base their operational decisions on average values of the parameters that depend on other members. However, in real-life operation the variability of said parameters decreases the link profits. Thus, a cooperative arrangement may be devised in which a link agrees to reduce the variability of its behavior to enhance the performance of other links, receiving compensation in return. This work shows the application of simulation and decision trees to assess the feasibility of this cooperation scheme, from the perspective of the central link of a three member supply chain. First, the operational parameters of the link are optimized for mean values of the variables set by adjacent members. Then, by simulating the system for different probability distributions of these variables, graphs of the expected link gain versus the variances of the distributions are plotted. The results are incorporated to decision trees to evaluate the collaboration feasibility. It was found that the increased variability of the behavior of one neighboring member decreases the benefit of lowering the variability of the behavior of the other. The manuscript closes with a discussion of the practical viability of this collaboration scheme.

  19. Relative Importance of Central and Peripheral Adiposities on Cardiometabolic Variables in Females: A Japanese Population-Based Study.

    Science.gov (United States)

    Kouda, Katsuyasu; Dongmei, Namiraa; Tamaki, Junko; Iki, Masayuki; Tachiki, Takahiro; Kajita, Etsuko; Nakatani, Yoshimi; Uenishi, Kazuhiro; Kagamimori, Sadanobu; Kagawa, Yoshiko; Yoneshima, Hideo

    In epidemiological studies, there is little evidence regarding the relative impact of central adiposity and peripheral adiposity on cardiometabolic risk factors, especially in Asian populations. This study investigated associations between central-to-peripheral fat ratios and cardiometabolic variables using data from a population-based study of Japanese women. The source population was composed of 1800 women aged 50 yr or older at the 15th- to 16th-yr follow-up survey of the Japanese Population-Based Osteoporosis Cohort Study. This study analyzed cross-sectional data from 998 women for whom complete information about body fat variables according to dual-energy X-ray absorptiometry, cardiometabolic variables, and potential confounding factors was available. Both before and after adjusting for potential confounding factors, trunk-to-appendicular fat ratios showed significant (p variables were independent of relationships between fat volumes (in whole body or in trunk) and cardiometabolic variables. Furthermore, relationships between trunk-to-appendicular fat ratios and cardiometabolic variables were observed among women in the lowest tertile of total body fat (brachial-ankle pulse wave velocity, β = 0.08; high-density lipoprotein cholesterol, β = -0.32; low-density lipoprotein cholesterol, β = 0.15; and hemoglobin A1C, β = 0.16; p variables than peripheral adiposity. Information on central-to-peripheral fat ratios is particularly valuable for the evaluation of relatively thin Japanese women. Copyright © 2016 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  20. Mechanistic studies of flux variability of neutral and ionic permeants during constant current dc iontophoresis with human epidermal membrane.

    Science.gov (United States)

    Li, S Kevin; Higuchi, William I; Kochambilli, Rajan P; Zhu, Honggang

    2004-04-01

    Although constant current iontophoresis is supposed to provide constant transdermal transport, significant flux variability and/or time-dependent flux drifts are observed during iontophoresis with human skin in vitro and human studies in vivo. The objectives of the present study were to determine (a) the causes of flux variability in constant current dc transdermal iontophoresis and (b) the relationships of flux variabilities among permeants of different physicochemical properties. Changes in the human epidermal membrane (HEM) effective pore size and/or electroosmosis during constant current dc iontophoresis were examined. Tetraethylammonium ion (TEA), urea, and mannitol were the model permeants. For the neutral permeants, the results in the present study showed a significant increase of fluxes with time in a given experiment and large HEM sample-to-sample variability. Although both effective pore size and pore charge density variations contributed to the time-dependent flux drifts observed in electroosmotic transport, the significant flux drifts observed were found to be primarily a result of the time-dependent increase in effective pore charge density. For the ionic permeant, the observed flux variability was smaller than that of the neutral permeants and was believed to be primarily due to effective pore size alteration in HEM during iontophoresis as suggested in a previous study. The different extents of flux variability observed between neutral and ionic permeants are consistent with the different iontophoretically enhanced transport mechanisms for the neutral and ionic permeants (i.e. electroosmosis and electrophoresis, respectively). The results of the present study also demonstrate that flux variability of two neutral permeants are inter-related, so the flux of one neutral permeant can be predicted if the permeability coefficient of the other neutral permeant is known.

  1. A Study of Risk Factors and T- Score Variability in Romanian Women with Postmenopausal Osteoporosis.

    Directory of Open Access Journals (Sweden)

    Rodica TöRöK-Oance

    2013-12-01

    Full Text Available The purpose of this study was to analyse the prevalence of postmenopausal osteoporosis risk factors and to analyse the T-score variability in spine and hip according to the associated risk factors.This is a retrospective study (2003-2007 including 177 female patients with postmenopausal osteoporosis. The patients were separated in seven groups according to the number of risk factors per case. The T-score was compared between this groups using unpaired t-Student test.The most frequent risk factor was early menopause (44.63%, followed by low consumption of dairy products (37.29%, coffee consumption (25.99%, sedentary lifestyle (20.9%, smoking (19.21%, delayed menarche (15.25%, low body mass index (10.71%, nulliparity (7.91%, alcohol consumption (0.56%. The maximum number of risk factors per case was six. The T-score decreased with increasing number of risk factors. T-score differences are statistically significant when comparing cases with 6 risk factors to cases with 5 risk factors (P=0.0315 in spine; P=0.0088 in hip, 4 risk factors (P=0.0076 in spine; P=0.043 in hip, 3 risk factors (P<0.0001 in spine; P=0.0205 in hip, 2 risk factors (P=0.0012 in spine; P<0.0001 in hip, a single risk factor (P<0.001 in spine and hip and no risk factor (P=0.0075 in spine; P=0.0006 in hip.Association of several risk factors leads to decrease of T-score so being able to avoid any such factors may contribute to a better bone mineral density. This could be achieved by the education of female population regarding postmenopausal osteoporosis risk factors, followed by adopting an appropriate lifestyle and diet.

  2. Effects of design and operating variables on process characteristics in a methane discharge: a numerical study

    Science.gov (United States)

    Bera, K.; Farouk, B.; Lee, Y. H.

    2001-05-01

    A self-consistent two-dimensional radio frequency capacitively coupled glow discharge model has been developed in cylindrical coordinates for a methane discharge using a fluid model. The objective of the study is to identify the effects of design and operating variables of the reactor on the process characteristics such as the deposition rate, uniformity and the quality of the diamond-like-carbon film. The simulations provide insights to charged species dynamics and investigate their effects on the plasma process for a depositing methane discharge. The model includes continuity equations for electrons and positive and negative ions, and energy equation for electrons. Swarm data as a function of electron energy are provided as input to the model. The model predicts the electron density, ion density, and their fluxes and energies to the cathode. The roles of electrons, dominating ions and radicals in a capacitively coupled discharge are investigated. The radical and neutral densities in the discharge are calculated using a gas phase chemistry model. The diamond-like-carbon thin-film deposition rate is predicted using surface chemistry model. The gas phase chemistry model considers diffusion of radicals and neutrals along with creation and loss terms. The surface deposition/etching process involves adsorption-desorption, adsorption layer reaction, ion stitching, direct ion incorporation, etching and carbon sputtering. A systematic parametric study of plasma processing has been performed to identify process parameters to obtain better film deposition/etching on a wafer. The present work shows how plasma equipment simulation can be used for the practical investigation and optimization of a plasma-assisted chemical vapour deposition process. The simultaneous treatment of plasma dynamics and surface processes enables a very precise prediction of the process characteristics in terms of the film deposition rate, uniformity and the quality as functions of discharge control

  3. Epidemiologic variability of chronic inflammatory demyelinating polyneuropathy with different diagnostic criteria: study of a UK population.

    Science.gov (United States)

    Rajabally, Yusuf A; Simpson, Benjamin S; Beri, Sushil; Bankart, John; Gosalakkal, Jayaprakash A

    2009-04-01

    Epidemiologic data on chronic inflammatory demyelinating polyneuropathy (CIDP) is limited, and previous studies have shown variable results. The frequencies of CIDP subtypes remain unknown. Variations due to use of different diagnostic criteria have not been studied. We examined the prevalence and incidence of CIDP in Leicestershire and Rutland, UK (population 963,600). Prevalence day was 1 May 2008. The prevalence of CIDP fulfilling the 2006 clinical and electrophysiologic European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria was 4.77 per 100,000 (95% confidence interval [CI] 3.49-6.37). Using the 1991 American Academy of Neurology (AAN) criteria, the prevalence was 1.97 per 100,000 in this population (95% CI 1.19-3.08). Lewis-Sumner syndrome was diagnosed in 15.2% of patients, and 23.9% had pure sensory onset. Over 40% required no immunotherapy, and 84.6% of those treated responded. More than 80% of the AAN criteria-negative but EFNS/PNS criteria-positive patients were responsive to treatment. Both sets of criteria were equally likely to identify patients who required therapy. The mean annual incidence rate over the 3 years preceding the prevalence day was 0.70 per 100,000/year using EFNS/PNS criteria (95% CI 0.43-1.08), and 0.35 per 100,000/year using AAN criteria (95% CI 0.17-0.64). We conclude that the AAN criteria may underestimate prevalence and incidence of the disease. The EFNS/PNS criteria provide higher diagnostic sensitivity and are of greater clinical relevance, and they also offer a useful breakdown of the epidemiologic data for CIDP subtypes.

  4. Individual Variables, Attitudes towards English and Being a Teacher: A study on Prospective Teachers of English

    Directory of Open Access Journals (Sweden)

    Berna Güryay

    2016-05-01

    Full Text Available The achievement in learning a foreign language depends not only on cognitive factors such as intelligence, aptitude etc., but also on affective factors such as attitude and motivation. As the main branch of prospective teachers of English is teaching a language, their attitudes towards English and towards being a teacher are of vital importance in their future careers. The purpose of this descriptive study is to determine whether the attitudes of the students of English Language Teaching Department towards English affect their attitudes towards being a teacher of English and whether the students’ attitudes indicate significant differences with regard to individual variables such as gender, class, the types of High Schools from which they have graduated, their socio-economic background, and whether there is a teacher in their family. The sample group of the study were composed 540 prospective English teachers of the first, second, third and fourth year students of the Department of English Language Teaching at Buca Faculty of Education at Dokuz Eylül University, İzmir. For data collection, personal information sheet, the scale for attitudes towards English developed by Altunay (2002 (Alpha Reliability Coefficient: 0.96 and the scale for attitudes towards Being a Teacher developed by Semerci (1999 (Alpha Reliability Coefficient: 0.68 were used. The results indicate that the more positive the students’ attitudes towards English are, the more positive the students’ attitudes towards teaching profession are. Fur thermore, when attitudes towards English and towards being a teacher are compared,” it is indicated that the students’ attitudes towards English are a little bit higher.

  5. Exposure assessment and heart rate variability monitoring in workers handling titanium dioxide particles: a pilot study

    Science.gov (United States)

    Ichihara, Sahoko; Li, Weihua; Omura, Seiichi; Fujitani, Yuji; Liu, Ying; Wang, Qiangyi; Hiraku, Yusuke; Hisanaga, Naomi; Wakai, Kenji; Ding, Xuncheng; Kobayashi, Takahiro; Ichihara, Gaku

    2016-03-01

    Titanium dioxide (TiO2) particles are used for surface coating and in a variety of products such as inks, fibers, food, and cosmetics. The present study investigated possible respiratory and cardiovascular effects of TiO2 particles in workers exposed to this particle at high concentration in a factory in China. The diameter of particles collected on filters was measured by scanning electron microscopy. Real-time size-dependent particle number concentration was monitored in the nostrils of four workers using condensation particle counter and optical particle counter. Electrocardiogram was recorded using Holter monitors for the same four workers to record heart rate variability. Sixteen workers underwent assessment of the respiratory and cardiovascular systems. Mass-based individual exposure levels were also measured with personal cascade impactors. The primary particle diameter ranged from 46 to 562 nm. Analysis of covariance of the pooled data of the four workers showed that number of particles with a diameter <300 nm was associated positively with total number of N-N and negatively with total number of increase or decrease in successive RR intervals greater than 50 ms (RR50+/-) or percentage of RR 50+/- that were parameters of parasympathetic function. The total mass concentration was 9.58-30.8 mg/m3 during work, but significantly less before work (0.36 mg/m3). The clear abnormality in respiratory function was not observed in sixteen workers who had worked for 10 months to 13 years in the factory. The study showed that exposure to particles with a diameter <300 nm might affect HRV in workers handling TiO2 particles. The results highlight the need to investigate the possible impact of exposure to nano-scaled particles on the autonomic nervous system.

  6. Heart rate variability during treatment of breakthrough pain in patients with advanced cancer: a pilot study

    Science.gov (United States)

    Masel, Eva Katharina; Huber, Patrick; Engler, Tobias; Watzke, Herbert Hans

    2016-01-01

    Background Decisions on the intensity of analgesic therapy and judgments regarding its efficacy are difficult at the end of life, when many patients are not fully conscious and pain is a very common symptom. In healthy individuals and in postoperative settings, nociception and subsequent pain relief have been shown to induce changes in the autonomic nervous system (ANS), which can be detected by measuring heart rate variability (HRV). Objectives The changes in the ANS were studied by measuring HRV during opioid therapy for cancer breakthrough pain (CBTP) in palliative-care patients with cancer and compared these changes with patient-reported pain levels on a numeric rating scale (NRS). Patients and methods The study included ten patients with advanced cancer and baseline opioid therapy. In each patient, a 24-hour peak-to-peak HRV measurement with a sampling rate of 4,000 Hz was performed. High frequency (HF), low frequency (LF), total power, pNN50 (indicating parasympathetic activity), and log LF/HF were obtained in two intervals prior to therapy and in four intervals thereafter. Intensity of CBTP was recorded using a patient-reported NRS prior to therapy and 30 minutes afterward. Results CBTP occurred in seven patients (three males and four females; mean age: 62 ± 5.2 years) and was treated with opioids. A highly significant positive correlation was found between opioid-induced reduction in patient-reported pain intensity based on NRS and changes in log LF/HF (r > 0.700; p 2 points on the NRS but remained unchanged in the other patients. Conclusion Our data suggest that log LF/HF may be a useful surrogate marker for alleviation of CBTP in patients with advanced cancer and might allow detection of pain without active contribution from patients. PMID:28003771

  7. Comparative study of a responsive insertion technology (RIT colonoscope versus a variable-stiffness colonoscope

    Directory of Open Access Journals (Sweden)

    César Prieto-de-Frías

    2013-04-01

    Full Text Available Background and objectives: recently, Olympus developed a new prototype (XCF-Q180AY2L with responsive insertion technology (RIT, which besides the still known variable stiffness technology, included a passive bending section and a new high force insertion tube. Our objective was to investigate whether the use of this prototype could ease colonoscope insertion, increasing the cecal intubation rate, and/or shortening the cecal intubation time. Material and methods: the study was designed as a prospective observational study in 305 consecutive patients from a colo-rectal cancer screening program. We compared colonoscopies performed with conventional colonoscopes (CFH180AL/CFQ160L with those performed with the prototype XCF-Q180AY2L. End points were mean cecal and terminal ileal intubation times, cecum intubation rate, and need for specific maneuvers. All colonoscopies were performed under sedation with intravenous propofol. Finally, 288 patients were included. Results: no complications were observed. Complete cecal intubation rate was 100 % in both groups. The ileum could be reached in 98.95 % of cases. Mean time required to reach the cecum was shorter in the prototype endoscope group (4.31 min, SD 2.63 min than in the conventional endoscope group (4.66 min, SD 2.52 min (p < 0.05. Compared with the standard colonoscope group, we observed in the prototype group less subjective sensation of difficulty in the passage of the sigma (p < 0.01, fewer maneuvers when it proved necessary to straighten the scope (p < 0.01, and less frequent need to modify the stiffness of the endoscope (p < 0.05. Conclusion: we concluded that the prototype endoscope (XCF-Q180AY2L facilitated colonoscope insertion, requiring slightly less time to reach the cecum than a standard colonoscope.

  8. Causes of sore throat after intubation: a prospective observational study of multiple anesthesia variables.

    Science.gov (United States)

    Levin, Phillip D; Chrysostomos, Chrysostomou; Ibarra, Carlos A; Ledot, Stephan; Naito, Daigo; Weissman, Charles; Avidan, Alexander

    2017-06-01

    Sore throat is common after intubation for surgery. This observational study investigated cuff pressure and a large range of clinical covariates to explore the etiology of sore throat. Approximately 24 hours after surgery six questions relating to pain, upper airway symptoms and sore throat were delivered to patients who had undergone intubation. Sore throat was correlated with demographics, anesthesia variables and cuff pressure (measured for a subset of patients). Sore throat was reported by 270/518 (52%) patients with VAS Score 45.9±25.1 (range 0-100). Sore throat patients were significantly younger, had a lower ASA status, were more frequently female, had shorter surgeries and lower nitrous oxide exposure, had a higher proportion of smaller tracheal tubes (7.5 mm internal diameter vs. 8 mm), had a higher incidence of nasogastric drainage, higher propofol doses and a higher usage of ketorolac. Decreasing age (odds ratio 0.976, 95% confidence intervals 0.961-0.992, P=0.003) and the presence of a nasogastric tube when the questionnaire was delivered (OR 1.83, 95% CI: 1.06-3.14, P=0.03) remained significant predictors of sore throat on multivariate analysis. Mean cuff pressure (measured for 160 patients) was 56.8±41.9 mmHg. Cuff pressure was similar amongst patients with and without sore throat (57±46 vs. 53±38 mmHg, P=0.58). There was no correlation between cuff pressure and severity of sore throat (r=0.004, P=0.37). Only age and the presence of a nasogastric tube after surgery were significant predictors for sore throat. This result contradicts most other studies of cuff pressure where fewer covariates were measured.

  9. Influence from genetic variability on opioid use for cancer pain: a European genetic association study of 2294 cancer pain patients

    DEFF Research Database (Denmark)

    Klepstad, P; Fladvad, T; Skorpen, F;

    2011-01-01

    Cancer pain patients need variable opioid doses. Preclinical and clinical studies suggest that opioid efficacy is related to genetic variability. However, the studies have small samples, findings are not replicated, and several candidate genes have not been studied. Therefore, a study of genetic...... variability with opioid doses in a large population using a confirmatory validation population was warranted. We recruited 2294 adult European patients using a World Health Organization (WHO) step III opioid and analyzed single nucleotide polymorphisms (SNPs) in genes with a putative influence on opioid...... mechanisms. The patients' mean age was 62.5 years, and the average pain intensity was 3.5. The patients' primary opioids were morphine (n=830), oxycodone (n=446), fentanyl (n=699), or other opioids (n=234). Pain intensity, time on opioids, age, gender, performance status, and bone or CNS metastases predicted...

  10. A Brief Study, Research, Design, Analysis on Multi Section Variable Camber Wing

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    ArimalaParamasivamSruthi

    2015-08-01

    Full Text Available Minimizing fuel consumption is one of the major concerns in the aviation industry. In the past decade, there have been many attempts to improve the fuel efficiency of aircraft. One of the methods proposed is to vary the lift-to-drag ratio of the aircraft in different flight conditions. To achieve this, the wing of the airplane must be able to change its configuration during flight, corresponding to different flight regimes.In the research presented in this thesis, the aerodynamic characteristics of a multisection, variable camber wing were investigated. The model used in this research had a 160mm chord and a 200mm wingspan, with the ribs divided into 4 sections. Each section was able to rotate approximately 5 degrees without causing significant discontinuity on the wing surface. Two pneumatic actuators located at the main spar were used to morph the wing through mechanical linkages. The multi-section variable camber wing model could provide up to 10 percent change in camber from the baseline configuration, which had a NACA0015 section.The wing was tested in the free-jet wind tunnel at three different Reynolds numbers: 322000, 48000, and 636000. Static tests were performed to obtain lift and drag data for different configurations. Two rigid wings in baseline and camber configuration were built and tested to compare the test data with variable camber wing. The wind tunnel test results indicated that the multisection variable camber wing provided a higher lift than the rigid wing in both configurations whereas high drag was also generated on the variable camber wing due to friction drag on the wing skin. The larger drag value appeared on variable camber wing in baseline configuration than in cambered configuration resulting in lower lift-to-drag ratio as compared to the baseline rigid wing whereas the variable camber wing in cambered configuration had higher lift-to-drag ratio than the cambered rigid wing.

  11. Latent variable modelling of risk factors associated with childhood diseases: Case study for Nigeria

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    Khaled Khatab

    2011-09-01

    Full Text Available Objective: To investigate the impact of various bio-demographic and socio-economic variables on joint childhood diseases in Nigeria with flexible geoadditive probit models. Methods: Geoadditive latent variable model (LVM was applied where the three observable disease (diarrhea, cough, fever variables were modelled as indicators for the latent individual variable "health status" or "frailty" of a child. This modelling approach allowed us to investigate the common influence of risk factors on individual frailties of children, thereby automatically accounting for association between diseases as indicators for health status. The LVM extended to analyze the impact of risk factors and the spatial effects on the unobservable variable “health status ” of a child less than 5 years of age using the 2003 Demographic and Health Surveys (DHS data for Nigeria. Results: The results suggest some strong underlying spatial patterns of the three ailments with a clear southeastern divide of childhood morbidities and this might be the results in the overlapping of the various risk factors. Conclusions: Comorbidity with conditions such as cough, diarrhoea and fever is common in Nigeria. However, little is known about common risk factors and geographical overlaps in these illnesses. The search for overlapping common risk factors and their spatial effects may improve our understanding of the etiology of diseases for efficient and cost-effective control and planning of the three ailments.

  12. Ensemble spectral variability study of Active Galactic Nuclei from the XMM-Newton serendipitous source catalogue

    CERN Document Server

    Serafinelli, Roberto; Middei, Riccardo

    2016-01-01

    The variability of the X-ray spectra of active galactic nuclei (AGN) usually includes a change of the spectral slope. This has been investigated for a small sample of local AGNs by Sobolewska and Papadakis, who found that slope variations are well correlated with flux variations, and that spectra are typically steeper in the bright phase (softer when brighter behaviour). Not much information is available for the spectral variability of high-luminosity AGNs and quasars. In order to investigate this phenomenon, we use data from the XMM-Newton Serendipitous Source Catalogue, Data Release 5, which contains X-ray observations for a large number of active galactic nuclei in a wide luminosity and redshift range, for several different epochs. This allows to perform an ensemble analysis of the spectral variability for a large sample of quasars. We quantify the spectral variability through the spectral variability parameter $\\beta$, defined as the ratio between the change in spectral slope and the corresponding logarit...

  13. Developmental Changes in the Variability of Tongue and Lip Movements during Speech from Childhood to Adulthood: An EMA Study

    Science.gov (United States)

    Murdoch, Bruce E.; Cheng, Hei-Yan; Goozee, Justine V.

    2012-01-01

    This study investigated the developmental variability of lip and tongue movement in 48 children and adults. Motion of the tongue-tip, tongue-body and lower lip was recorded using electromagnetic articulography during productions of sentences containing /t/, /s/, /l/, /k/ and /p/. Four groups of speakers participated in the study: (1) aged 6-7…

  14. Predicting Preservice Music Teachers' Performance Success in Instrumental Courses Using Self-Regulated Study Strategies and Predictor Variables

    Science.gov (United States)

    Ersozlu, Zehra N.; Nietfeld, John L.; Huseynova, Lale

    2017-01-01

    The purpose of this study was to examine the extent to which self-regulated study strategies and predictor variables predict performance success in instrumental performance college courses. Preservice music teachers (N = 123) from a music education department in two state universities in Turkey completed the Music Self-Regulated Studying…

  15. A Study into the Relationship of Personal Characteristics of Preschool Pre-Service Teachers with Some Variables

    Directory of Open Access Journals (Sweden)

    Ümit DENİZ

    2012-08-01

    Full Text Available The current study was carried out to investigate the relationship of personal characteristics of preschool pre-service teachers with some variables. The sample is 449 pre-service teachers attending to Faculty of Education, the Department of Preschool Teaching of five universities in Turkey. The data of the research was gathered through Data Collection Form and Eysenck Personality Questionnaire-Shortened Form (EPQ. In the analysis of the data, mean scores for four dimensions of EPQ were obtained. The relation between the mean scores obtained while the variables of class and gender was studied through t test and the relation between parents education level and score means was studied through “one way variance analysis (ANOVA. No relation was found between the class and parents education levels and personality sub-dimensions. A significant relation was found between the variables of gender and lying sub-dimensions, and between the mother education level and extraversion sub-dimension.

  16. Outline of an Anthropological Contribution to the Study of Snake Venom Variability: The Case of Echis sp. Envenomation

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    Tilman Musch

    2014-03-01

    Full Text Available An understanding of the variability of snake venom composition is of high relevance for adequate treatment of snakebites. Clinical observations of bite victims are considered as a first step in the study of venom variability. The present paper suggests the study of local clinical observations made by healers as an anthropological contribution to the interdisci-plinary research of venom variability on a species and subspecies level. Such an anthropological contribution will take into account cultural particularities of a region. In order to illustrate his approach, the author describes his ethnozoological and ethnomedical fieldwork among Zarma and Tuareg in western Niger where he studied envenomation by Echis leucogaster. This species is of particular interest, as no medical descriptions of envenomation resulting from its bites seem to exist.

  17. Heart Rate Variability, Insulin Resistance, and Insulin Sensitivity in Japanese Adults: The Toon Health Study

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    Isao Saito

    2015-09-01

    Full Text Available Background: Although impaired cardiac autonomic function is associated with an increased risk of type 2 diabetes in Caucasians, evidence in Asian populations with a lower body mass index is limited. Methods: Between 2009–2012, the Toon Health Study recruited 1899 individuals aged 30–79 years who were not taking medication for diabetes. A 75-g oral glucose tolerance test was used to diagnose type 2 diabetes, and fasting and 2-h-postload glucose and insulin concentrations were measured. We assessed the homeostasis model assessment index for insulin resistance (HOMA-IR and Gutt’s insulin sensitivity index (ISI. Pulse was recorded for 5 min, and time-domain heart rate variability (HRV indices were calculated: the standard deviation of normal-to-normal intervals (SDNN and the root mean square of successive difference (RMSSD. Power spectral analysis provided frequency domain measures of HRV: high frequency (HF power, low frequency (LF power, and the LF:HF ratio. Results: Multivariate-adjusted logistic regression models showed decreased SDNN, RMSSD, and HF, and increased LF:HF ratio were associated significantly with increased HOMA-IR and decreased ISI. When stratified by overweight status, the association of RMSSD, HF, and LF:HF ratio with decreased ISI was also apparent in non-overweight individuals. The interaction between LF:HF ratio and decreased ISI in overweight individuals was significant, with the odds ratio for decreased ISI in the highest quartile of LF:HF ratio in non-overweight individuals being 2.09 (95% confidence interval, 1.41–3.10. Conclusions: Reduced HRV was associated with insulin resistance and lower insulin sensitivity. Decreased ISI was linked with parasympathetic dysfunction, primarily in non-overweight individuals.

  18. Reducing SAR in parallel excitation using variable-density spirals: a simulation-based study.

    Science.gov (United States)

    Liu, Yinan; Feng, Ke; McDougall, Mary P; Wright, Steven M; Ji, Jim

    2008-10-01

    Parallel excitation using multiple transmit channels has emerged as an effective method to shorten multidimensional spatially selective radiofrequency (RF) pulses, which have a number of important applications, including B1 field inhomogeneity correction in high-field MRI. The specific absorption rate (SAR) is a primary concern in high-field MRI, where wavelength effects can lead to local peaks in SAR. In parallel excitation, the subjects are exposed to RF pulses from multiple coils, which makes the SAR problem more complex to analyze, yet potentially enables greater freedom in designing RF pulses with lower SAR. Parallel-excitation techniques typically employ either Cartesian or constant-density (CD) spiral trajectories. In this article, variable-density (VD) spiral trajectories are explored as a means for SAR reduction in parallel-excitation pulse design. Numerical simulations were conducted to study the effects of CD and VD spirals on parallel excitation. Specifically, the electromagnetic fields of a four-channel transmit head coil with a three-dimensional head model at 4.7 T were simulated using a finite-difference time domain method. The parallel RF pulses were designed and the resulting excitation patterns were generated using a Bloch simulator. The SAR distributions due to CD and VD spirals were evaluated quantitatively. The simulation results show that, for the same pulse duration, parallel excitation with VD spirals can achieve a lower SAR compared to CD spirals for parallel excitation. VD spirals also resulted in reduced artifact power in the excitation patterns. This gain came with slight, but noticeable, degrading of the spatial resolution of the resulting excitation patterns.

  19. Cephalic versus digital plethysmographic variability index measurement: a comparative pilot study in cardiac surgery patients.

    Science.gov (United States)

    Fischer, Marc-Olivier; Pellissier, Arnaud; Saplacan, Vladimir; Gérard, Jean-Louis; Hanouz, Jean-Luc; Fellahi, Jean-Luc

    2014-12-01

    Noninvasive measurement of digital plethysmographic variability index (PVI(digital)) has been proposed to predict fluid responsiveness, with conflicting results. The authors tested the hypothesis that cephalic sites of PVI measurement (namely PVI(ear) and PVI(forehead)) could be more discriminant than PVI(digital) to predict fluid responsiveness after cardiac surgery. A prospective observational study. A cardiac surgical intensive care unit of a university hospital. Fifty adult patients. Investigation before and after fluid challenge. Patients were prospectively included within the first 6-hour postoperative period and investigated before and after fluid challenge. A positive response to fluid challenge was defined as a 15% increase in cardiac index. PVI(digital), PVI(ear), PVI(forehead), and invasive arterial pulse-pressure variation (PPV) measurements were recorded simultaneously, and receiver operating characteristic (ROC) curves were built. Forty-one (82%) patients were responders and 9 (18%) patients were nonresponders to fluid challenge. ROCAUC were 0.74 (95% confidence interval [95% CI]: 0.60-0.86), 0.81 (95% CI: 0.68-0.91), 0.88 (95% CI: 0.75-0.95) and 0.87 (95% CI: 0.75-0.95) for PVI(digital), PVI(ear), PVI(forehead), and PPV, respectively. Significant differences were observed between PVI(forehead) and PVI(digital) (absolute difference in ROCAUC = 0.134 [95% CI: 0.003-0.265], p = 0.045) and between PPV and PVI(digital) (absolute difference in ROCAUC = 0.129 [95% CI: 0.011-0.247], p = 0.033). The percentage of patients within the inconclusive class of response was 46%, 70%, 44%, and 26% for PVI(digital), PVI(ear), PVI(forehead), and PPV, respectively. PVI(forehead) was more discriminant than PVI(digital) and could be a valuable alternative to arterial PPV in predicting fluid responsiveness. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Correlates to the variable effects of cannabis in young adults: a preliminary study

    Directory of Open Access Journals (Sweden)

    Camera Ariella A

    2012-03-01

    Full Text Available Abstract Background Cannabis use can frequently have adverse affects in those that use it and these can be amplified by various characteristics of an individual, from demographic and environmental variations to familial predisposition for mental illnesses. Methods The current study of 100 individuals, who were cannabis users during their adolescence and may still be users, was a survey of the self perceived effects of cannabis and their correlates. A reliable family member was also interviewed for determination of family history of various major mental illnesses and substance use. Results As many as 40% of cannabis users had paranoid feelings (suspiciousness when using cannabis, although the most frequent effect was feeling relaxed (46%. Having a familial background for mental illnesses such as depression or schizophrenia did not determine the effects of cannabis nor its pattern of use, although the number of subjects with such a history was small. An age at which an individual began using cannabis did have an effect on how heavily it was used and the heavier the cannabis use, the more likely the individual was also to have had psychotic symptoms after use. There were no sex differences in effects of cannabis. These results are tempered by the reliance on self-report for many of the variables ascertained. Conclusion Cannabis can frequently have negative effects in its users, which can be amplified by certain demographic and/or psychosocial factors. Thus, users with a specific profile may be at a higher risk of unpleasant effects from cannabis use and caution should be noted when cannabis is administered to young people for medicinal purposes.

  1. Study on Variable Capacity Control Mechanism of Scroll Compressor for Automotive Air Conditioner

    Science.gov (United States)

    Hirano, Takahisa; Shigeoka, Tetsuo

    As for the automotive air conditioner, (1) to keep the automotive cabin temperature in a comfortable region, (2) to improve driving feeling, (3) to drive the air conditioning system economically through all seasons, are universally required. Recently, from these points, compressors with variable capacity control mechanism for automotive air conditioners have been remarkably requested. We have developed a scroll comoressor with variable capacity control mechanism. The capacity control mechanism, which changes the channel area of the bypass hole continuously, according to the suction gas pressure and the discharge gas pressure, has been developed. In this report, we describe the mechanism of variable capacity control and the performance simulation program that has been developed for the scroll compressor. Further, we describe the measuring results of cylinder pressure behavior, the results of energy loss analysis and the effect of comfort, drivability, power saving in the refrigerating cycle using the developed capacity control compressor.

  2. Flicker study on variable speed wind turbines with doubly fed induction generators

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    Grid connected wind turbines may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a doubly fed induction generator developed in the simulation tool of PSCAD/EMTDC. Flicker emission of variable speed wind turbines...... with doubly fed induction generators is investigated during continuous operation, and the dependence of flicker emission on mean wind speed, wind turbulence intensity, short circuit capacity of grid and grid impedance angle are analyzed. A comparison is done with the fixed speed wind turbine, which leads...... to a conclusion that the factors mentioned above have different influences on flicker emission compared with that in the case of the fixed speed wind turbine. Flicker mitigation is realized by output reactive power control of the variable speed wind turbine with doubly fed induction generator. Simulation results...

  3. Systematic Study of Gamma-ray bright Blazars with Optical Polarization and Gamma-ray Variability

    CERN Document Server

    Itoh, Ryosuke; Fukazawa, Yasushi; Uemura, Makoto; Tanaka, Yasuyuki T; Kawabata, Koji S; Madejski, Grzegorz M; Schinzel, Frank K; Kanda, Yuka; Shiki, Kensei; Akitaya, Hiroshi; Kawabata, Miho; Moritani, Yuki; Nakaoka, Tatsuya; Ohsugi, Takashi; Sasada, Mahito; Takaki, Katsutoshi; Takata, Koji; Ui, Takahiro; Yamanaka, Masayuki; Yoshida, Michitoshi

    2016-01-01

    Blazars are highly variable active galactic nuclei which emit radiation at all wavelengths from radio to gamma-rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies and it also varies dramatically. The polarization of blazars is of interest for understanding the origin, confinement, and propagation of jets. However, even though numerous measurements have been performed, the mechanisms behind jet creation, composition and variability are still debated. We performed simultaneous gamma-ray and optical photopolarimetry observations of 45 blazars between Jul. 2008 and Dec. 2014 to investigate the mechanisms of variability and search for a basic relation between the several subclasses of blazars. We identify a correlation between the maximum degree of optical linear polarization and the gamma-ray luminosity or the ratio of gamma-ray to optical fluxes. Since the maximum polarization degree depends on the condition of the magnetic field (chaotic or ordered), thi...

  4. A variable-geometry combustor used to study primary and secondary zone stoichiometry

    Science.gov (United States)

    Briehl, D.; Schultz, D. F.; Ehlers, R. C.

    1983-01-01

    A combustion program is underway to evaluate fuel quality effects on gas turbine combustors. A rich-lean variable geometry combustor design was chosen to evaluate fuel quality effects over a wide range of primary and secondary zone equivalence ratios at simulated engine operating conditions. The first task of this effort, was to evaluate the performance of the variable geometry combustor. The combustor incorporates three stations of variable geometry to control primary and secondary zone equivalence ratio and overall pressure loss. Geometry changes could be made while a test was in progress through the use of remote control actuators. The primary zone liner was water cooled to eliminate the concern of liner durability. Emissions and performance data were obtained at simulated engine conditions of 80 percent and full power. Inlet air temperature varied from 611 to 665K, inlet total pressure varied from 1.02 to 1.24 MPa, reference velocity was a constant 1400 K.

  5. An exploratory study of the hard X-ray variability properties of PG quasars with RXTE

    CERN Document Server

    Guainazzi, M; Giallongo, E; Laor, A; Elvis, M; Siemiginowska, A L

    2000-01-01

    We have monitored with the RXTE PCA the variability pattern of the 2-20 keV flux in four PG quasars (QSOs) from the Laor et al. (1994) sample. Six observations of each target at regular intervals of 1 day were performed. The sample comprises objects with extreme values of Balmer line width (and hence soft X-ray steepness) and spans about one order of magnitude in luminosity. The most robust result is that the variability amplitude decreases as energy increases. Several options for a possible ultimate driver of the soft and hard X-ray variability, such as the influx rate of Comptonizing relativistic particles, instabilities in the accretion flow or the number of X-ray active sites, are consistent with our results.

  6. Study on Short-term Variability of Ship Responses in Waves

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Iseki, Toshio

    2015-01-01

    Short-term variability of ship responses is investigated by cross-spectrum analysis. In a steady state condition, it is well known that a certain length of sampled data is required for stable results of the spectral analysis. However, the phase lag between responses, in terms of the phase angle...... of the cross-spectra, has not been discussed in detail. Using long stationary time series, the transition of amplitudes and relative phase angles of the cross-spectra has been investigated by iterative analyzes with a few seconds of time shifting. In the results, the short-term variability of the relative...... phase angle was observed. In effect, the variability may compromise the accuracy of the wave buoy analogy....

  7. Modelling and control of variable speed wind turbines for power system studies

    DEFF Research Database (Denmark)

    Michalke, Gabriele; Hansen, Anca Daniela

    2010-01-01

    Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed...... and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride-through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally......, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride-through grid faults. Copyright © 2009 John Wiley & Sons, Ltd....

  8. Prediction of experimental data for an independent variable using the experimental data collected for other independent variables in a study of skin cancer caused by exposure to UV radiation.

    Science.gov (United States)

    Hashemi, Ray R; Bahar, Mahmood; Tang, Nan; Tyler, Alexander A; Hinson, William

    2003-05-01

    In this study, two algorithms (ONE and TWO) are introduced to determine the position of the t-distribution of variable V(i) (with 95% confidence) in the treated group in reference to the t-distribution of variable V(i) (with 95% confidence) in the control group of an experimental study involving UV radiation exposure of a group of rodents. The outcome of applying the two algorithms is two discretized files. A reduct of each file is generated using the rough sets methodology and then the measurements for one independent variable are predicted using the measurements of the other independent variables in the same reduct. The rough sets methodology and the fuzzy-rough classifier are used for this prediction. The results reveal that (1) algorithm TWO is the best, (2) the values for non-core variables are predicted with minimum accuracy of 87%, and (3) the prediction of values for core variables is not successful.

  9. Evaluating climate variables, indexes and thresholds governing Arctic urban sustainability: case study of Russian permafrost regions

    Science.gov (United States)

    Anisimov, O. A.; Kokorev, V.

    2013-12-01

    Addressing Arctic urban sustainability today forces planners to deal with the complex interplay of multiple factors, including governance and economic development, demography and migration, environmental changes and land use, changes in the ecosystems and their services, and climate change. While the latter can be seen as a factor that exacerbates the existing vulnerabilities to other stressors, changes in temperature, precipitation, snow, river and lake ice, and the hydrological regime also have direct implications for the cities in the North. Climate change leads to reduced demand for heating energy, on one hand, and heightened concerns about the fate of the infrastructure built upon thawing permafrost, on the other. Changes in snowfall are particularly important and have direct implications for the urban economy, as together with heating costs, expenses for snow removal from streets, airport runways, roofs and ventilation corridors underneath buildings erected on pile foundations on permafrost constitute the bulk of the city's maintenance budget. Many cities are located in river valleys and are prone to flooding that leads to enormous economic losses and casualties, including human deaths. The severity of the northern climate has direct implications for demographic changes governed by regional migration and labor flows. Climate could thus be viewed as an inexhaustible public resource that creates opportunities for sustainable urban development. Long-term trends show that climate as a resource is becoming more readily available in the Russian North, notwithstanding the general perception that globally climate change is one of the challenges facing humanity in the 21st century. In this study we explore the sustainability of the Arctic urban environment under changing climatic conditions. We identify key governing variables and indexes and study the thresholds beyond which changes in the governing climatic parameters have significant impact on the economy

  10. Relationships betveen pain intensity and heart rate variability in patients after abdominal surgery: a pilot study

    Institute of Scientific and Technical Information of China (English)

    CHANG Ling-hua; MA Tso-chiang; TSAY Shiow-luan; JONG Gwo-ping

    2012-01-01

    Background A link between postoperative pain intensity and heart rate variability (HRV) had not been well established.This study aimed to investigate the correlation between post-operative pain intensity and HRV.Methods The subjects in this cross-sectional correlation study comprised of patients who had undergone abdominal surgery in a regional teaching hospital in central Taiwan during the period July 2009-November 2009.The visual analogue scale (VAS) and the short-form McGill pain questionnaire (SF-MPQ) were used to measure post-operative pain.HRV was measured as the standard deviation of normal RR interval,and by power spectral analysis that included high frequency (HF),low frequency (LF),very low frequency power,and LF/HF ratio.Results Atotal of 34 subjects were included in this study.We found that the day after the surgery,the mean VAS score was 47.50±20.98 and the mean SF-MPQ score was 18.06±8.90,indicating a moderate degree of pain.Moderate to severe degrees of tenderness were reported by 70.6% of the patients,moderate to severe degrees of gnawing pain were experienced by 67.7% of the patients,moderate to severe degrees of tiring-exhaustion pain were reported by 64.7% of the patients,and 41.2% of the patients who experienced moderate to severe pain believed that the pain was punishing-cruel.The standard deviation of normal RR interval and high frequency values obtained from male patients or married patients were higher than female patients or unmarried (P <0.05).The correlation of the standard deviation of normal RR interval,high frequency,very low frequency value and patient's age were negative (p <0.05).The total SF-MPQ pain scores positively correlated with the LF/HF ratio (P <0.05).Conclusions The multidimensional pain assessment tool (SF-MPQ) reflects better the patients' post-operative pain than the single-dimensional assessment tool (VAS).HRV positively correlated with SF-MPQ scores in patients after abdominal surgery.

  11. STUDY ON THE VIBRATION CHARACTERISTIC OF THE METAL PUSHING BELT CONTINUOUSLY VARIABLE TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The solid and finite element model of metal pushing type continuously variable transmission are established at speed ratio of i=0.5 and i=2.0.In order to solve the problem of the complicated of structure,the node-node rod discrete finite element model is put forward and the whole system is simplified and established.The natural frequency and mode shape of system are solved by iterative Lanczos-reduce method for sensitivity analysis in finite element model.The new method and the result can be used to improve the smoothness of the variable transmission system and to propose the theory for reducing noise at operation.

  12. Effects of the psycholinguistic variables on the lexical decision task in Spanish: a study with 2,765 words.

    Science.gov (United States)

    González-Nosti, María; Barbón, Analía; Rodríguez-Ferreiro, Javier; Cuetos, Fernando

    2014-06-01

    In order to explore the role of the main psycholinguistic variables on visual word recognition, several mega-studies have been conducted in English in recent years. Nevertheless, because the effects of these variables depend on the regularity of the orthographic system, studies must also be done in other languages with different characteristics. The goal of this work was to conduct a lexical decision study in Spanish, a language with a shallow orthography and a high number of words. The influence of psycholinguistic variables on latencies corresponding to 2,765 words was assessed by means of linear mixed-effects modeling. The results show that some variables, such as frequency or age of acquisition, have significant effects on reaction times regardless of the type of words used. Other variables, such as orthographic neighborhood or imageability, were significant only in specific groups of words. Our results highlight the importance of taking into account the peculiarities of each spelling system in the development of reading models.

  13. Association Between Long-Term Blood Pressure Variability and 10-Year Progression in Arterial Stiffness: The Multiethnic Study of Atherosclerosis.

    Science.gov (United States)

    Tedla, Yacob G; Yano, Yuichiro; Carnethon, Mercedes; Greenland, Philip

    2017-01-01

    Experimental studies conducted on animal and human endothelium suggested that higher systolic blood pressure (SBP) variability reduces bioavailability of nitric oxide and increases vascular smooth muscle cell proliferation. These vascular wall changes could stiffen the arterial wall. Using data from the Multiethnic Study of Atherosclerosis, we investigated the association between long-term SBP variability and 10-year percent change in arterial stiffness among 1122 individuals (mean age 57 years, 46% males at baseline) who were not taking antihypertensive medications. Within-individual standard deviation, variability independent of the mean, and coefficient of variation of SBP across 5 visits were used to capture long-term SBP variability. Carotid arterial stiffness was measured using distensibility coefficient and Young's elastic modulus at baseline and after a mean of 9.5 years of follow-up (visit 5). In a multivariate linear regression model, individuals in the fifth quintile as compared with those in the first quintile of standard deviation, variability independent of the mean, and coefficient of variation of SBP had a 9.8% (95% confidence interval [CI] -17.0%, -2.7%), 6.4% (95% CI -13.2%, 0.4%), and 8.7% (95% CI -15.4%, -1.9%) higher decline in distensibility coefficient and a 27.5% (95% CI 15.8%, 39.3%), 25.8% (95% CI 14.7%, 36.9%), and 27.9% (95% CI 16.8%, 39.1%) higher progression in Young's elastic modulus, respectively, after 10 years of follow-up. Linear trends in the decline of distensibility coefficient and progression of Young's elastic modulus were observed across the quintiles of SBP variability indices. These findings suggest that higher long-term SBP variability may be a risk factor for arterial stiffness progression independent of mean BP. © 2016 American Heart Association, Inc.

  14. Geographic variability of fatal road traffic injuries in Spain during the period 2002–2004: an ecological study

    Directory of Open Access Journals (Sweden)

    Jimenez-Puente Alberto

    2007-09-01

    Full Text Available Abstract Background The aim of the present study is to describe the inter-province variability of Road Traffic Injury (RTI mortality on Spanish roads, adjusted for vehicle-kilometres travelled, and to assess the possible role played by the following explicative variables: sociodemographic, structural, climatic and risk conducts. Methods An ecological study design was employed. The mean annual rate of RTI deaths was calculated for the period 2002–2004, adjusted for vehicle-kilometres travelled, in the 50 provinces of Spain. The RTI death rate was related with the independent variables described above, using simple and multiple linear regression analysis with backward step-wise elimination. The level of statistical significance was taken as p Results In the period 2002–2004 there were 12,756 RTI deaths in Spain (an average of 4,242 per year, SD = 356.6. The mean number of deaths due to RTI per 100 million vehicle-kilometres (mvk travelled was 1.76 (SD = 0.51, with a minimum value of 0.66 (in Santa Cruz de Tenerife and a maximum of 3.31 (in the province of Lugo. All other variables being equal, a higher proportion of kilometres available on high capacity roads, and a higher cultural and education level were associated with lower death rates due to RTI, while the opposite was true for the rate of alcohol consumers and the road traffic volume of heavy vehicles. The variables included in the model accounted for 55.4% of the variability in RTI mortality. Conclusion Adjusting RTI mortality rates for the number of vehicle-kilometres travelled enables us to identify the high variability of this cause of death, and its relation with risk factors other than those inherent to human behaviour, such as the type of roads and the type of vehicles using them.

  15. Does internal climate variability overwhelm climate change signals in streamflow? The upper Po and Rhone basin case studies

    Energy Technology Data Exchange (ETDEWEB)

    Fatichi, S., E-mail: simone.fatichi@ifu.baug.ethz.ch; Rimkus, S.; Burlando, P.; Bordoy, R.

    2014-09-15

    Projections of climate change effects in streamflow are increasingly required to plan water management strategies. These projections are however largely uncertain due to the spread among climate model realizations, internal climate variability, and difficulties in transferring climate model results at the spatial and temporal scales required by catchment hydrology. A combination of a stochastic downscaling methodology and distributed hydrological modeling was used in the ACQWA project to provide projections of future streamflow (up to year 2050) for the upper Po and Rhone basins, respectively located in northern Italy and south-western Switzerland. Results suggest that internal (stochastic) climate variability is a fundamental source of uncertainty, typically comparable or larger than the projected climate change signal. Therefore, climate change effects in streamflow mean, frequency, and seasonality can be masked by natural climatic fluctuations in large parts of the analyzed regions. An exception to the overwhelming role of stochastic variability is represented by high elevation catchments fed by glaciers where streamflow is expected to be considerably reduced due to glacier retreat, with consequences appreciable in the main downstream rivers in August and September. Simulations also identify regions (west upper Rhone and Toce, Ticino river basins) where a strong precipitation increase in the February to April period projects streamflow beyond the range of natural climate variability during the melting season. This study emphasizes the importance of including internal climate variability in climate change analyses, especially when compared to the limited uncertainty that would be accounted for by few deterministic projections. The presented results could be useful in guiding more specific impact studies, although design or management decisions should be better based on reliability and vulnerability criteria as suggested by recent literature. - Highlights:

  16. Proposed Standards for Variable Harmonization Documentation and Referencing: A Case Study Using QuickCharmStats 1.1.

    Science.gov (United States)

    Winters, Kristi; Netscher, Sebastian

    2016-01-01

    Comparative statistical analyses often require data harmonization, yet the social sciences do not have clear operationalization frameworks that guide and homogenize variable coding decisions across disciplines. When faced with a need to harmonize variables researchers often look for guidance from various international studies that employ output harmonization, such as the Comparative Survey of Election Studies, which offer recoding structures for the same variable (e.g. marital status). More problematically there are no agreed documentation standards or journal requirements for reporting variable harmonization to facilitate a transparent replication process. We propose a conceptual and data-driven digital solution that creates harmonization documentation standards for publication and scholarly citation: QuickCharmStats 1.1. It is free and open-source software that allows for the organizing, documenting and publishing of data harmonization projects. QuickCharmStats starts at the conceptual level and its workflow ends with a variable recording syntax. It is therefore flexible enough to reflect a variety of theoretical justifications for variable harmonization. Using the socio-demographic variable 'marital status', we demonstrate how the CharmStats workflow collates metadata while being guided by the scientific standards of transparency and replication. It encourages researchers to publish their harmonization work by providing researchers who complete the peer review process a permanent identifier. Those who contribute original data harmonization work to their discipline can now be credited through citations. Finally, we propose peer-review standards for harmonization documentation, describe a route to online publishing, and provide a referencing format to cite harmonization projects. Although CharmStats products are designed for social scientists our adherence to the scientific method ensures our products can be used by researchers across the sciences.

  17. Sleep quality, the neglected outcome variable in clinical studies focusing on locomotor system; a construct validation study

    Directory of Open Access Journals (Sweden)

    Röder Christoph

    2010-09-01

    Full Text Available Abstract Background In addition to general health and pain, sleep is highly relevant to judging the well-being of an individual. Of these three important outcome variables, however, sleep is neglected in most outcome studies. Sleep is a very important resource for recovery from daily stresses and strains, and any alteration of sleep will likely affect mental and physical health, especially during disease. Sleep assessment therefore should be standard in all population-based or clinical studies focusing on the locomotor system. Yet current sleep assessment tools are either too long or too specific for general use. Methods Based on a literature review and subsequent patient-based rating of items, an expert panel designed a four-item questionnaire about sleep. Construct validation of the questionnaire in a random sample of the German-speaking Swiss population was performed in 2003. Reliability, correlation, and tests for internal consistency and validity were analyzed. Results Overall, 16,634 (70% out of 23,763 eligible individuals participated in the study. Test-retest reliability coefficients ranged from 0.72 to 0.87, and a Cronbach's alpha of 0.83 indicates good internal consistency. Results show a moderate to good correlation between sleep disturbances and health perception, and between sleep disturbances and overall pain. Conclusions The Sleep Standard Evaluation Questionnaire (SEQ-Sleep is a reliable and short tool with confirmed construct validity for sleep assessment in population-based observational studies. It is easy to administer and therefore suitable for postal surveys of the general population. Criterion validity remains to be determined.

  18. Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study

    NARCIS (Netherlands)

    Wentink, E.C.; Koopman, H.F.J.M.; Stramigioli, S.; Rietman, J.S.; Veltink, P.H.

    2013-01-01

    Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic

  19. Biologically variable respiration as a stochastic process in ventilation - a stochastic model study.

    Science.gov (United States)

    Min, Kyongyob; Hosoi, Keita; Degami, Masayuki; Kinoshita, Yoshinori

    2010-01-01

    Based on the fractal bronchial tree, we introduced a function of "asynchronous phasic contractions of lobular bronchiole", which would generate fluctuations in tidal volumes. Stochastic control theory was able to describe a genesis of biological variability in spontaneous respirations using a Schroedinger wave function.

  20. Characteristic Analysis and Experimental Study of a Hybrid Permanent Magnet Variable Flux Memory Motor

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Variable flux permanent magnet (PM) memory motors (VFMM), which combine the advantages of PM machines with high power density and electrically excited machines with controllable air-gap magnetic flux, have been widely concerned and researched in recent years.

  1. Heart rate variability and skin conductance biofeedback: A triple-blind randomized controlled study

    NARCIS (Netherlands)

    Raaijmakers, S.F.; Steel,F.W.; Goede, M. de; Wouwe, N.C. van; Erp, J.B.F. van; Brouwer, A.M.

    2013-01-01

    High heart rate variability (HRV) and low skin conductance level (SCL) have been associated with low levels of stress. Biofeedback - providing an individual with online information about his or her own physiological state – may help to change these signals in the desired direction and therewith impr

  2. A QSAR Study of Environmental Estrogens Based on a Novel Variable Selection Method

    Directory of Open Access Journals (Sweden)

    Aiqian Zhang

    2012-05-01

    Full Text Available A large number of descriptors were employed to characterize the molecular structure of 53 natural, synthetic, and environmental chemicals which are suspected of disrupting endocrine functions by mimicking or antagonizing natural hormones and may thus pose a serious threat to the health of humans and wildlife. In this work, a robust quantitative structure-activity relationship (QSAR model with a novel variable selection method has been proposed for the effective estrogens. The variable selection method is based on variable interaction (VSMVI with leave-multiple-out cross validation (LMOCV to select the best subset. During variable selection, model construction and assessment, the Organization for Economic Co-operation and Development (OECD principles for regulation of QSAR acceptability were fully considered, such as using an unambiguous multiple-linear regression (MLR algorithm to build the model, using several validation methods to assessment the performance of the model, giving the define of applicability domain and analyzing the outliers with the results of molecular docking. The performance of the QSAR model indicates that the VSMVI is an effective, feasible and practical tool for rapid screening of the best subset from large molecular descriptors.

  3. Performance Variables and Professional Experience in Simulated Laparoscopy: A Two-Group Learning Curve Study

    NARCIS (Netherlands)

    Luursema, J.M.; Rovers, Maroeska M.; Groenier, Marleen; van Goor, Harry

    2014-01-01

    Objective Virtual reality simulators are increasingly used in laparoscopy training. Such simulators allow objective assessment of performance. However, both low-level variables and overall scores generated by the simulator can be hard to interpret. We present a method to generate intermediate

  4. Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines: a Parameter Study

    NARCIS (Netherlands)

    Jarquin Laguna, A.; Diepeveen, N.F.B.

    2013-01-01

    In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed w

  5. Heart rate variability and skin conductance biofeedback: A triple-blind randomized controlled study

    NARCIS (Netherlands)

    Raaijmakers, S.F.; Steel,F.W.; Goede, M. de; Wouwe, N.C. van; Erp, J.B.F. van; Brouwer, A.M.

    2013-01-01

    High heart rate variability (HRV) and low skin conductance level (SCL) have been associated with low levels of stress. Biofeedback - providing an individual with online information about his or her own physiological state – may help to change these signals in the desired direction and therewith

  6. A genome-wide methylation study on obesity Differential variability and differential methylation

    NARCIS (Netherlands)

    Xu, Xiaojing; Su, Shaoyong; Barnes, Vernon A.; De Miguel, Carmen; Pollock, Jennifer; Ownby, Dennis; Shi, Huidong; Zhu, Haidong; Snieder, Harold; Wang, Xiaoling

    2013-01-01

    Besides differential methylation, DNA methylation variation has recently been proposed and demonstrated to be a potential contributing factor to cancer risk. Here we aim to examine whether differential variability in methylation is also an important feature of obesity, a typical non-malignant common

  7. Vibration Reduction of Helicopter Blade Using Variable Dampers: A Feasibility Study

    Science.gov (United States)

    Lee, George C.; Liang, Zach; Gan, Quan; Niu, Tiecheng

    2002-01-01

    In the report, the investigation of controlling helicopter-blade lead-lag vibration is described. Current practice of adding passive damping may be improved to handle large dynamic range of the blade with several peaks of vibration resonance. To minimize extra-large damping forces that may damage the control system of blade, passive dampers should have relatively small damping coefficients, which in turn limit the effectiveness. By providing variable damping, a much larger damping coefficient to suppress the vibration can be realized. If the damping force reaches the maximum allowed threshold, the damper will be automatically switched into the mode with smaller damping coefficient to maintain near-constant damping force. Furthermore, the proposed control system will also have a fail-safe feature to guarantee the basic performation of a typical passive damper. The proposed control strategy to avoid resonant regions in the frequency domain is to generate variable damping force in combination with the supporting stiffness to manipulate the restoring force and conservative energy of the controlled blade system. Two control algorithms are developed and verified by a prototype variable damper, a digital controller and corresponding algorithms. Primary experiments show good potentials for the proposed variable damper: about 66% and 82% reductions in displacement at 1/3 length and the root of the blade respectively.

  8. Heart rate variability and skin conductance biofeedback: A triple-blind randomized controlled study

    NARCIS (Netherlands)

    Raaijmakers, S.F.; Steel,F.W.; Goede, M. de; Wouwe, N.C. van; Erp, J.B.F. van; Brouwer, A.M.

    2013-01-01

    High heart rate variability (HRV) and low skin conductance level (SCL) have been associated with low levels of stress. Biofeedback - providing an individual with online information about his or her own physiological state – may help to change these signals in the desired direction and therewith impr

  9. Analyzing Regression-Discontinuity Designs with Multiple Assignment Variables: A Comparative Study of Four Estimation Methods

    Science.gov (United States)

    Wong, Vivian C.; Steiner, Peter M.; Cook, Thomas D.

    2012-01-01

    In a traditional regression-discontinuity design (RDD), units are assigned to treatment and comparison conditions solely on the basis of a single cutoff score on a continuous assignment variable. The discontinuity in the functional form of the outcome at the cutoff represents the treatment effect, or the average treatment effect at the cutoff.…

  10. Predicting gender differences as latent variables: summed scores, and individual item responses: a methods case study

    Directory of Open Access Journals (Sweden)

    Jacobs Danny O

    2004-10-01

    Full Text Available Abstract Background Modeling latent variables such as physical disability is challenging since its measurement is performed through proxies. This poses significant methodological challenges. The objective of this article is to present three different methods to predict latent variables based on classical summed scores, individual item responses, and latent variable models. Methods This is a review of the literature and data analysis using "layers of information". Data was collected from the North Carolina Back Pain Project, using a modified version of the Roland Questionnaire. Results The three models are compared in relation to their goals and underlying concepts, previous clinical applications, data requirements, statistical theory, and practical applications. Initial linear regression models demonstrated a difference in disability between genders of 1.32 points (95% CI 0.65, 2.00 on a scale from 0–23. Subsequent item analysis found contradictory results across items, with no clear pattern. Finally, IRT models demonstrated three items were demonstrated to present differential item functioning. After these items were removed, the difference between genders was reduced to 0.78 points (95% CI, -0.99, 1.23. These results were shown to be robust with re-sampling methods. Conclusions Purported differences in the levels of a latent variable should be tested using different models to verify whether these differences are real or simply distorted by model assumptions.

  11. A genome-wide methylation study on obesity Differential variability and differential methylation

    NARCIS (Netherlands)

    Xu, Xiaojing; Su, Shaoyong; Barnes, Vernon A.; De Miguel, Carmen; Pollock, Jennifer; Ownby, Dennis; Shi, Huidong; Zhu, Haidong; Snieder, Harold; Wang, Xiaoling

    2013-01-01

    Besides differential methylation, DNA methylation variation has recently been proposed and demonstrated to be a potential contributing factor to cancer risk. Here we aim to examine whether differential variability in methylation is also an important feature of obesity, a typical non-malignant common

  12. Study of multiple cracks in airplane fuselage by micromechanics and complex variables

    Science.gov (United States)

    Denda, Mitsunori; Dong, Y. F.

    1994-01-01

    Innovative numerical techniques for two dimensional elastic and elastic-plastic multiple crack problems are presented using micromechanics concepts and complex variables. The simplicity and the accuracy of the proposed method will enable us to carry out the multiple-site fatigue crack propagation analyses for airplane fuselage by incorporating such features as the curvilinear crack path, plastic deformation, coalescence of cracks, etc.

  13. A Photometric Study of the Pulsating Variable Star TYC 0075 01143 1

    Science.gov (United States)

    Khruslov, A. V.; Kusakin, A. V.

    2013-09-01

    We present the results of our new observations of TYC 0075 01143 1, a recently discovered double-mode delta Scuti variable. We improved the frequencies f0 and f1 and pulsation amplitudes, detected the interaction frequencies f1+f0, f1-f0, and a possible nonradial frequency fN.

  14. A Correlational Study of Preadmission Predictor Variables and Dental School Performance.

    Science.gov (United States)

    Kress, Gerard C.; Dogon, I. Leon

    1981-01-01

    Undergraduate performance and standardized test scores were correlated with dental school performance for 131 members of nine Harvard School of Dental Medicine classes to determine the predictive validity of the earlier variables. The only significant positive correlation was of the Dental Admission Test and dental National Board Examination, part…

  15. Literacy in the Southern Sudan: A Case Study of Variables Affecting Literacy Programs.

    Science.gov (United States)

    Cowan, J. Ronayne

    1983-01-01

    Describes the Local Languages Literacy Project in the Southern Sudan; delineates the most important educational, socioeconomic, and linguistic variables affecting the success of large-scale literacy programs in Africa; and questions the widely held assumption that indigenous language literacy is essential to subsequent literacy in the prestige…

  16. A modelling study of photochemical regimes over Europe: robustness and variability

    Directory of Open Access Journals (Sweden)

    M. Beekmann

    2009-01-01

    Full Text Available The variability of the relative sensitivity to volatile organic compounds (VOC or NOx emissions, the chemical regime, over Europe during summers 2001 to 2003 is simulated with a regional scale transport-chemistry model. The robustness of chemical regimes is shown. A VOC sensitive regime over North-Western Europe and a mainly NOx sensitive regime over the Mediterranean basin and Eastern Europe are found, confirming earlier published results. The chemical regime time variability, its robustness to several environmental factors (seasonality, interannual variability and to model uncertainty are thoroughly analysed. The chemical regime spatial structure only slightly depends on the ozone target considered (daily ozone maximum or AOT40, SOMO35, .... Differences between particular years and summer months are weak. Day to day variability is significant but does not change the occurrence of one or another chemical regime over North-Western Europe and the Mediterranean basin. Expected decreases in anthropogenic NOx emissions over Europe since the last and for the next few decades have shifted and will shift chemical regimes to more NOx sensitive. The predictive and explanatory use of chemical regime indicator species is also investigated. For all cases but near ship tracks over the Mediterranean basin, the spatial pattern of chemical regimes appears to be robust with respect to model uncertainty.

  17. Historical range of variability in landscape structure: a simulation study in Oregon, USA.

    Science.gov (United States)

    Etsuko Nonaka; Thomas A. Spies

    2005-01-01

    We estimated the historical range of variability (HRV) of forest landscape structure under natural disturbance regimes at the scale of a physiographic province (Oregon Coast Range, 2 million ha) and evaluated the similarity to HRV of current and future landscapes under alternative management scenarios. We used a stochastic fire simulation model to simulate...

  18. Historical range of variability in live and dead wood biomass: a regional-scale simulation study

    Science.gov (United States)

    Etsuko Nonaka; Thomas A. Spies; Michael C. Wimberly; Janet L. Ohmann

    2007-01-01

    The historical range of variability (HRV) in landscape structure and composition created by natural disturbance can serve as a general guide for evaluating ecological conditions of managed landscapes. HRV approaches to evaluating landscapes have been based on age classes or developmental stages, which may obscure variation in live and dead stand structure. Developing...

  19. Decifering mega-ripple variability in an anthropogenically steered environment: implications for mine burial studies

    OpenAIRE

    Papili, S.; Baeye, M.; Van Lancker, V.

    2013-01-01

    In 2007 the Ministery of Defence, in collaboration with Ghent University, developed a project on the understanding of mega-ripple variability in view of improving mine burial prediction models in sandbank areas. Results will assist in the monitoring of sea-mines, heritage of two World Wars, nowadays partially or totally buried by sandy bedforms.

  20. Retirement planning and work-related variables in Chinese older nurses: A cross-sectional study.

    Science.gov (United States)

    Liu, Peng-Cheng; Zhang, Huan-Huan; Zhang, Mei-Ling; Ying, Jie; Shi, Ying; Wang, Shou-Qi; Sun, Jiao

    2017-08-29

    To explore the situation of older nurses approaching retirement with regard to their retirement planning, and the relationship of their retirement planning behaviour with the job environment and job satisfaction under their current employment arrangements and other work-related variables. Nurse shortage has become a global phenomenon that can be alleviated by retaining older nurses in service. The Chinese government proposed the "Incremental Delay Retirement Age Policy." However, older nurses face delayed retirement but lack retirement plans. A cross-sectional questionnaire survey was conducted among a convenience sample of older retiring nurses (n = 152; 84.92% response rate) recruited from every department of four large general hospitals in Changchun, Jilin Province from June to August 2016. The majority of the respondents presented poor retirement planning (n = 122, 80.3%). The independent variables of information exchange with patients, teamwork and personal growth and development explained approximately 16.6% of the variance in retirement planning. Nurse-patient communication and personal growth and development can promote retirement planning, but teamwork is negatively related to retirement planning. Retirement planning by Chinese older nurses is related to certain work-related variables. However, many other work-related variables were not associated with retirement planning and require further research. Overall, Chinese older retiring nurses must improve their retirement planning practices. © 2017 John Wiley & Sons Ltd.

  1. Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines: a Parameter Study

    NARCIS (Netherlands)

    Jarquin Laguna, A.; Diepeveen, N.F.B.

    2013-01-01

    In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed w

  2. Performance variables and professional experience in simulated laparoscopy: a two-group learning curve study

    NARCIS (Netherlands)

    Luursema, J.M.; Rovers, M.M.; Groenier, M.; Goor, H. van

    2014-01-01

    OBJECTIVE: Virtual reality simulators are increasingly used in laparoscopy training. Such simulators allow objective assessment of performance. However, both low-level variables and overall scores generated by the simulator can be hard to interpret. We present a method to generate intermediate perfo

  3. Study on Short-term Variability of Ship Responses in Waves

    DEFF Research Database (Denmark)

    Iseki, Toshio; Nielsen, Ulrik Dam

    2014-01-01

    Short-term variability of ship responses is investigated from the view point of cross-spectrum analysis. In a steady state condition, it is well known that a certain length of sampled data are required for stable spectral analysis. However, the phase angle of the cross-spectra has not been discus...

  4. THE STUDY OF THE YELLOW SEA WARM CURRENT AND ITS SEASONAL VARIABILITY

    Institute of Scientific and Technical Information of China (English)

    XU Ling-ling; WU De-xing; LIN Xiao-pei; MA Chao

    2009-01-01

    The Yellow Sea Warm Current (YSWC) penetrates northward along the Yellow Sea Trough, and brings warm and saline water towards the Bohai Sea. The YSWC becomes much less intrusive in summer and is limited mostly in the southern trough, contrasting with a deep winter penetration well into the trough. The seasonal variability of the YSWC has prompted a debate regarding which controls the YSWC and its seasonal variability. In this article, the annual mean and seasonal variability of the YSWC was examined by using a 3-D ocean model together with several experiments. The results show that in the annual mean the YSWC is a compensating current firstly for the southward Korea Coastal Current (KCC), which is mainly caused by the Kuroshio Current (KC). The local wind-stress forcing plays an important but secondary role. However, the local monsoonal forcing plays a prominent role in modulating the seasonal variability. A deep northwestward intrusion of the YSWC in winter, for instance, is mainly due to a robustly developed China Coastal Current (CCC) which draws water along the Yellow Sea trough to feed a southward flow all the way from the Bohai Sea to the Taiwan Strait.

  5. Recently studied sedimentary records from the eastern Arabian Sea: Implications to Holocene monsoonal variability

    Digital Repository Service at National Institute of Oceanography (India)

    Agnihotri, R.; Kurian, S.

    in an attempt to comprehend past monsoonal variability in Indian as well as global context are reviewed. We also focus upon different proxies used so far in the Arabian Sea, their fidelity, limitations and future scope of using novel proxies for a better...

  6. Core biopsies of renal tumors: A study on diagnostic accuracy, interobserver, and intraobserver variability

    DEFF Research Database (Denmark)

    Kummerlin, I.; Kate, F. ten; Smedts, F.;

    2008-01-01

    Objective: The diagnostic accuracy of in-bench core biopsies (CBs) from renal masses, and the interobserver and intraobserver variability in pathological subtyping of renal tumors were assessed. Methods: We performed two CBs in 62 consecutive renal masses suspected for renal cell carcinoma (RCC...

  7. Steady-state visual evoked potentials in the low frequency range in migraine: a study of habituation and variability phenomena.

    Science.gov (United States)

    de Tommaso, Marina; Stramaglia, Sebastiano; Schoffelen, Jan Mathijs; Guido, Marco; Libro, Giuseppe; Losito, Luciana; Sciruicchio, Vittorio; Sardaro, Michele; Pellicoro, Mario; Puca, Franco Michele

    2003-08-01

    Previous studies have revealed that migraine patients display an increased photic driving to flash stimuli in the medium frequency range. The aim of this study was to perform a topographic analysis of steady-state visual evoked potentials (SVEPs) in the low frequency range (3-9 Hz), evaluating the temporal behaviour of the F1 amplitude by investigating habituation and variability phenomena. The main component of SVEPs, the F1, demonstrated an increased amplitude in several channels at 3 Hz. Behaviour of F1 amplitude was rather variable over time, and the wavelet-transform standard deviation was increased in migraine patients at a low stimulus rate. The discriminative value of the F1 mean amplitude and variability index, tested by both an artificial neural network classifier and a support vector machine, were high according to both methods. The increased photic driving in migraine should be subtended by a more generic abnormality of visual reactivity instead of a selective impairment of a visual subsystem. Temporal behaviour of SVEPs is not influenced by a clear tendency to habituation, but the F1 amplitude seemed to change in a complex way, which is better described by variability phenomena. An increased variability in response to flicker stimuli in migraine patients could be interpreted as an overactive regulation mechanism, prone to instability and consequently to headache attacks, whether spontaneous or triggered.

  8. Alarm Variables for Dengue Outbreaks: A Multi-Centre Study in Asia and Latin America.

    Directory of Open Access Journals (Sweden)

    Leigh R Bowman

    Full Text Available Worldwide, dengue is an unrelenting economic and health burden. Dengue outbreaks have become increasingly common, which place great strain on health infrastructure and services. Early warning models could allow health systems and vector control programmes to respond more cost-effectively and efficiently.The Shewhart method and Endemic Channel were used to identify alarm variables that may predict dengue outbreaks. Five country datasets were compiled by epidemiological week over the years 2007-2013. These data were split between the years 2007-2011 (historic period and 2012-2013 (evaluation period. Associations between alarm/ outbreak variables were analysed using logistic regression during the historic period while alarm and outbreak signals were captured during the evaluation period. These signals were combined to form alarm/ outbreak periods, where 2 signals were equal to 1 period. Alarm periods were quantified and used to predict subsequent outbreak periods. Across Mexico and Dominican Republic, an increase in probable cases predicted outbreaks of hospitalised cases with sensitivities and positive predictive values (PPV of 93%/ 83% and 97%/ 86% respectively, at a lag of 1-12 weeks. An increase in mean temperature ably predicted outbreaks of hospitalised cases in Mexico and Brazil, with sensitivities and PPVs of 79%/ 73% and 81%/ 46% respectively, also at a lag of 1-12 weeks. Mean age was predictive of hospitalised cases at sensitivities and PPVs of 72%/ 74% and 96%/ 45% in Mexico and Malaysia respectively, at a lag of 4-16 weeks.An increase in probable cases was predictive of outbreaks, while meteorological variables, particularly mean temperature, demonstrated predictive potential in some countries, but not all. While it is difficult to define uniform variables applicable in every country context, the use of probable cases and meteorological variables in tailored early warning systems could be used to highlight the occurrence of dengue

  9. Coffee Consumption and Heart Rate Variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) Cohort Study.

    Science.gov (United States)

    de Oliveira, Rackel Aguiar Mendes; Araújo, Larissa Fortunato; de Figueiredo, Roberta Carvalho; Goulart, Alessandra C; Schmidt, Maria Ines; Barreto, Sandhi Maria; Ribeiro, Antonio Luiz Pinho

    2017-07-13

    Studies have shown that acute coffee ingestion can affect cardiovascular autonomic activity, although the chronic effects on heart rate variability (HRV) remain controversial. A cross-sectional study with baseline data (2008-2010) from ELSA-Brasil cohort of 15,105 (aged 35-74), based in six Brazilian states. Coffee consumption in the previous 12 months was measured using the semi-quantitative food frequency questionnaire, and HRV was obtained through electrocardiographic tracings during 10 min at rest. Independent association between the frequency of coffee consumption "never or almost never", "≤1 cup/day", "2-3 cups/day", "≥3 cups/day", and HRV was estimated using generalized linear regression, adjusting for socio-demographic characteristics, health-related behavior, markers of abnormal metabolism, and the presence of coronary artery disease. Further, we applied Bonferroni correction in the full models. The mean age was 52 years (standard deviation (SD) = 9.1), and 52% was female; 9.5% never/almost never consumed coffee. In univariate analysis, coffee consumers had reduced values of HRV indexes, but after full adjustments and correction for multiple comparisons, these associations disappeared. A trend of reduction in HRV vagal indexes was observed in those that consumed ≥3 cups of coffee/day. Most of the effects attributed to the chronic use of coffee on the HRV indexes is related to the higher prevalence of unhealthy habits in coffee users, such as smoking and alcohol use. Adjustment for confounding factors weaken this association, making it non-significant. The effect of higher daily doses of coffee on the autonomic system should be evaluated in further studies.

  10. Coffee Consumption and Heart Rate Variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil Cohort Study

    Directory of Open Access Journals (Sweden)

    Rackel Aguiar Mendes de Oliveira

    2017-07-01

    Full Text Available Studies have shown that acute coffee ingestion can affect cardiovascular autonomic activity, although the chronic effects on heart rate variability (HRV remain controversial. Method: A cross-sectional study with baseline data (2008–2010 from ELSA-Brasil cohort of 15,105 (aged 35–74, based in six Brazilian states. Coffee consumption in the previous 12 months was measured using the semi-quantitative food frequency questionnaire, and HRV was obtained through electrocardiographic tracings during 10 min at rest. Independent association between the frequency of coffee consumption “never or almost never”, “≤1 cup/day”, “2–3 cups/day”, “≥3 cups/day”, and HRV was estimated using generalized linear regression, adjusting for socio-demographic characteristics, health-related behavior, markers of abnormal metabolism, and the presence of coronary artery disease. Further, we applied Bonferroni correction in the full models. Results: The mean age was 52 years (standard deviation (SD = 9.1, and 52% was female; 9.5% never/almost never consumed coffee. In univariate analysis, coffee consumers had reduced values of HRV indexes, but after full adjustments and correction for multiple comparisons, these associations disappeared. A trend of reduction in HRV vagal indexes was observed in those that consumed ≥3 cups of coffee/day. Conclusion: Most of the effects attributed to the chronic use of coffee on the HRV indexes is related to the higher prevalence of unhealthy habits in coffee users, such as smoking and alcohol use. Adjustment for confounding factors weaken this association, making it non-significant. The effect of higher daily doses of coffee on the autonomic system should be evaluated in further studies.

  11. A study of fluid flow and combustion with variable valve timing

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, F.

    1998-10-01

    The effects of variable valve timing (VVT) were examined by in-cylinder Laser Doppler Velocimetry flow measurements and heat-release calculations. A single-cylinder Volvo B5254 engine was used for all experiments and the valve timing was altered by phasing or exchanging the camshaft. Special cam lobes were developed for simulation of throttle-less operation. With the standard double camshaft, a tumbling flow was generated and with valve deactivation, a swirling flow was generated. The turbulence was increased with valve deactivation. This increased the combustion rate making lean burn possible. The standard camshaft with inlet valve deactivation and late cam phasing had a faster combustion at {lambda} = 1.8 than the standard camshaft with normal cam phasing at {lambda} = 1.0. Early and late inlet valve closing was used for enabling throttle-less operation. Early inlet valve closing (EIVC) generated a very slow tumble with low turbulence. Late inlet valve closing generated both very high and low turbulence. The net indicated efficiency was improved with up to 10%. Some reduction was observed for the gross indicated efficiency, due to a too large reduction in effective compression ratio. A very stable combustion was obtained for EIVC with gasoline, possibly due to a sheering flow over the inlet valves resulting in improved fuel-air preparation. Wavelet analysis was used for dividing LDV flow measurements into time and frequency resolved information. The technique rendered the same flow results as the moving window technique, but with a separation of the turbulence into different frequencies. The choice of wavelet was shown not to be crucial. The frequency resolved turbulence was studied for tumble and swirl. A tumbling flow had a larger transfer of energy from low frequency turbulence into high frequency turbulence than a swirling flow. This is caused by the tumble breakdown. A correlation against heat-release indicated that high frequency turbulence have a larger

  12. Adsorption edge study about cadmium, copper, nickel and zinc adsorption by variable charge soils

    Science.gov (United States)

    Casagrande, J. C.; Mouta, E. R.; Soares, M. R.

    2009-04-01

    The improper discharge of industrial and urban residues and the inadvertent use of fertilizers and pesticides can result in soil and water pollution and improve the potential of trace metals to enter in the human food chain. Adsorption reactions occur at the solid/liquid interface and are the most important mechanisms for controlling the activity of metal ions in soil solution. In a complex system with amphoteric behavior, the comprehension of the mobility, availability and fate of pollutants in the soil system is crucial for the prediction of the environmental consequences and for development of prevention/remediation strategies. A comparative study of cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) adsorption by highly weathered soils was carried out. Surface (0-0.2m) and subsoil (B horizon) samples were taken from a Rhodic Kandiudalf (RH), an Anionic "Xanthic" Acrudox (XA) and an Anionic "Rhodic" Acrudox (RA), located in brazilian humid tropical area. As the pH and the ionic strength are important environmental factors influencing the solution chemistry of heavy metals in variable charge systems, adsorption envelopes, in a batch adsorption experiment, were elaborated by reacting, for 24 h, soil samples with individual 0.01, 0.1 and 1.0 mol L-1 Ca(NO3)2 aqueous solutions containing nitrate salts of the adsorptive heavy metal (Cd, Cu, Ni and Zn) at the initial concentration of 5 mg L-1, with an increasing pH value from 3.0 to 8.0. pH50-100%, the difference between the pH of 100 and 50 percent metal adsorption was determined. A sharp increase of adsorption density (adsorption edge) was observed within a very narrow pH range, usually less than two pH units. Commonly, the relative affinity of a soil for a metal cation increases with the tendency of the cation to form inner-sphere surface complexes. This may be caused by differences in extent of hydrolysis of Cu ions and in affinity of adsorption sites for Cu. In general, subsurface samples showed low pH50

  13. Randomised Response Technique-An Innovative Method To Measure Culturally Sensitive Variables : Results From A Pilot Study

    Directory of Open Access Journals (Sweden)

    Soudarssanane M. B

    2003-01-01

    Full Text Available Research questions: What is the advantage of Randomized Response Technique (RRT over the conventional Direct Interview (DI and Anonymous Questionnaire (AQ in the assessment of culturally sensitive variables? Objectives: To compare the efficacy of the three methods, namely RRT, DI and AQ in the measurement of prevalence of Pre/Extra marital sex. Study design: Cross sectional study, using the three methods. Setting: A pilot study in a given community in Pondicherry. Statistical analysis: Probability equations. Results: The prevalence of pre/extra marital sex in the study population by the DI, AQ and RRT methods were 0%, 6% and 10% respectively in this pilot study. Conclusion: RRT improves validity of measurement of culturally sensitive variables both by ensuring a high participation in the study and by enabling a true response by assuring full confidentiality of information.

  14. Perceptions of Gender Group Variability in Majority and Minority Contexts Two Field Studies with Nurses and Police Officers

    OpenAIRE

    Hewstone, Miles; Crisp, Richard J.; Turner, Rhiannon N.

    2011-01-01

    Two field studies demonstrated that majority and minority size moderate perceived group variability. In Study 1 we found an outgroup homogeneity (OH) effect for female nurses in the majority, but an ingroup homogeneity (IH) effect for a token minority of male nurses. In Study 2 we found similar effects in a different setting - an OH effect for policemen in the majority and an IH effect for policewomen in the minority. Although measures of visibility, status, and, especially, familiarity tende...

  15. THE SLUDGE BATCH 7A GLASS VARIABILITY STUDY WITH FRIT 418 AND FRIT 702

    Energy Technology Data Exchange (ETDEWEB)

    Peeler, D; Edwards, T

    2011-03-24

    The Defense Waste Processing Facility (DWPF) is preparing to initiate processing of Sludge Batch 7a (SB7a) in May 2011. To support qualification of SB7a, the Savannah River National Laboratory (SRNL) was requested to execute a variability study (VS) to assess the applicability of the current Product Composition Control System (PCCS) durability models for the Frit 418-SB7a compositional region of interest. The objective of this study was to demonstrate applicability of the current durability models to the SB7a compositional region of interest and acceptability of the SB7a glasses with respect to the Environmental Assessment (EA) glass in terms of durability as defined by the Product Consistency Test (PCT). To support programmatic objectives, twenty-eight SB7a glasses were selected based on the nominal sludge projections used to support the frit recommendation. Twenty-three of the SB7a VS glasses were based on the use of Frit 418, while 5 glasses were based on the use of Frit 702. Frit 702 was also identified as a viable candidate for SB7a, especially if SO{sub 4} concentrations are found to be higher than anticipated. Frit 702 has shown a higher SO{sub 4} retention capability as compared to Frit 418. With respect to acceptability, the PCT results of the SB7a-VS glasses are acceptable relative to the EA glass regardless of thermal history (quenched or canister centerline cooled) or compositional view (target or measured). More specifically, all of the SB7a glasses have normalized boron release values (NL [B]) less than 0.9 g/L as compared to the benchmark NL [B] value for EA of 16.695 g/L. With respect to the applicability of the current durability models to the SB7a VS compositional region of interest, all of the study glasses (based on target compositions) lie within the 95% confidence intervals of the model predictions. When model applicability is based on the measured compositions, all of the SB7a VS glasses are predictable with the exception of SB7aVS-02 and SB7

  16. A comprehensive long term study of the radio and X-ray Variability of NGC 4051 Paper II

    CERN Document Server

    Jones, Sadie; Maccarone, Thomas J

    2016-01-01

    The origin of the low luminosity radio emission in radio-quiet AGN, is unknown. The detection of a positive correlation between the radio and X-ray emission would imply a jet-like origin, similar to that seen in `hard state' X-ray binary systems. In our previous work, we found no believable radio variability in the well known X-ray bright Seyfert 1 galaxy NGC 4051, despite large amplitude X-ray variability. In this study we have carefully re-analysed radio and X-ray observations using the same methods as our previous work, we again find no evidence for core radio variability. In direct contrast to our findings, another study claim significant radio variability and a distinctive anti-correlation between radio and X-ray data for the same source. The other study report only integral flux values and do not consider the effect of the changing array on the synthesised beam. In both our studies of NGC 4051 we have taken great care to account for the effect that the changing beam size has on the measured radio flux a...

  17. New Directions for the Study of Within-Individual Variability in Development: The Power of "N = 1"

    Science.gov (United States)

    Barbot, Baptiste; Perchec, Cyrille

    2015-01-01

    This article provides an introduction to the idiographic approach ("N = 1" research) in developmental psychology and an overview of methodological and statistical techniques employed to address the study of within-individual variability in development. Through a popularization of the idiographic approach and associated statistical…

  18. Longitudinal robustness of variables predicting independent gait following severe middle cerebral artery stroke: a prospective cohort study.

    NARCIS (Netherlands)

    Kollen, B.; Kwakkel, G.; Lindeman, E.

    2006-01-01

    OBJECTIVE: To determine within the first 10 weeks post onset the most robust variables in the prediction of recovery of independent gait at six months post stroke. DESIGN: A prospective cohort study. SUBJECTS: One hundred and one first ever ischaemic middle cerebral artery stroke patients. None of

  19. Longitudinal robustness of variables predicting independent gait following severe middle cerebral artery stroke: a prospective cohort study.

    NARCIS (Netherlands)

    Kollen, B.; Kwakkel, G.; Lindeman, E.

    2006-01-01

    OBJECTIVE: To determine within the first 10 weeks post onset the most robust variables in the prediction of recovery of independent gait at six months post stroke. DESIGN: A prospective cohort study. SUBJECTS: One hundred and one first ever ischaemic middle cerebral artery stroke patients. None of t

  20. Combining Event- and Variable-Centred Approaches to Institution-Facing Learning Analytics at the Unit of Study Level

    Science.gov (United States)

    Kelly, Nick; Montenegro, Maximiliano; Gonzalez, Carlos; Clasing, Paula; Sandoval, Augusto; Jara, Magdalena; Saurina, Elvira; Alarcón, Rosa

    2017-01-01

    Purpose: The purpose of this paper is to demonstrate the utility of combining event-centred and variable-centred approaches when analysing big data for higher education institutions. It uses a large, university-wide data set to demonstrate the methodology for this analysis by using the case study method. It presents empirical findings about…

  1. Variable Production of English Past Tense Morphology: A Case Study of a Thai-Speaking Learner of English

    Science.gov (United States)

    Prapobaratanakul, Chariya; Pongpairoj, Nattama

    2016-01-01

    The study investigated variable production of English past tense morphology by an L1 Thai-speaking learner of English. Due to the absence of the past tense inflectional morphology in the Thai language, production of English past tense morphemes poses a persistent problem for L1 Thai-speaking learners of English. Hypotheses have been made in…

  2. New Directions for the Study of Within-Individual Variability in Development: The Power of "N = 1"

    Science.gov (United States)

    Barbot, Baptiste; Perchec, Cyrille

    2015-01-01

    This article provides an introduction to the idiographic approach ("N = 1" research) in developmental psychology and an overview of methodological and statistical techniques employed to address the study of within-individual variability in development. Through a popularization of the idiographic approach and associated statistical…

  3. Influences of Selected Cognitive, Affective and Educational Variables on Sex-related Differences in Mathematics Learning and Studying.

    Science.gov (United States)

    Fennema, Elizabeth

    This paper offers a detailed review of the literature concerning sex differences in the learning of mathematics. It identifies cognitive, affective and educational variables which have been either shown or hypothesized to contribute to sex-related differences in mathematics learning. The author analyzes each study in detail. One important finding…

  4. Angiogenesis in breast cancer: a comparative study of the observer variability of methods for determining microvessel density

    DEFF Research Database (Denmark)

    Hansen, S; Grabau, D A; Rose, C;

    1998-01-01

    The purpose of this study was to evaluate the reliability of different methods for estimating neovascularization in breast cancer and to compare them in terms of observer variability. The microvessel endothelium was stained immunohistochemically by antibodies against CD34. The investigated method...

  5. [The Study of the Measurement of Heart Rate Variability Using ECG and Photoplethysmographic Signal].

    Science.gov (United States)

    Wang, Buqing; Chai, Xiaoke; Zhang Zhengbo; Wang, Weidong

    2015-07-01

    In comparison with the measurement of heart rate variability from ECG and from photoplethysmographic signal from 46 healthy adults in their spontaneous breathing state. The beat-to-beat intervals in ECG and pulse-to-pulse intervals in photoplethysmographic signal are extracted, and then the parameters of heart rate variability are calculated. Three kinds of algorithms are chosen to get the pulse-to-pulse intervals, which are the intervals of maximum of second derivative, the maximum of PPG signal and the tangent intersection. The results show that the correlation coefficients of the HRV parameters in the two calculation methods are highly correlated. The Bland-Altman scattered plots show the relative bias results from the algorithm of the maximum of PPG signal are smallest and singular points that deviate from the consistent limits are the least compared with the other two algorithms.

  6. Zero Distribution of System with Unknown Random Variables Case Study: Avoiding Collision Path

    Directory of Open Access Journals (Sweden)

    Parman Setyamartana

    2014-07-01

    Full Text Available This paper presents the stochastic analysis of finding the feasible trajectories of robotics arm motion at obstacle surrounding. Unknown variables are coefficients of polynomials joint angle so that the collision-free motion is achieved. ãk is matrix consisting of these unknown feasible polynomial coefficients. The pattern of feasible polynomial in the obstacle environment shows as random. This paper proposes to model the pattern of this randomness values using random polynomial with unknown variables as coefficients. The behavior of the system will be obtained from zero distribution as the characteristic of such random polynomial. Results show that the pattern of random polynomial of avoiding collision can be constructed from zero distribution. Zero distribution is like building block of the system with obstacles as uncertainty factor. By scale factor k, which has range, the random coefficient pattern can be predicted.

  7. Study and experimental verification of control tuning strategies in a variable speed wind energy conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Zaragoza, Jordi; Pou, Josep; Arias, Antoni [Electronic Engineering Dept., Technical University of Catalonia, Campus Terrassa, C. Colom 1, 08222 Terrassa (Spain); Spiteri, Cyril [Department of Industrial Electrical Power Conversion, University of Malta, Faculty of Engineering, Msida (Malta); Robles, Eider; Ceballos, Salvador [Energy Unit, Robotiker-Tecnalia Technology Corporation, Zamudio, Basque Country (Spain)

    2011-05-15

    This paper analyzes and compares different control tuning strategies for a variable speed wind energy conversion system (WECS) based on a permanent-magnet synchronous generator (PMSG). The aerodynamics of the wind turbine (WT) and a PMSG have been modeled. The control strategy used in this research is composed of three regulators, which may be based on either linear or nonlinear controllers. In this analysis, proportional-integral (PI) linear controllers have been used. Two different tuning strategies are analyzed and compared. The main goal is to enhance the overall performance by achieving a low sensitivity to disturbances and minimal overshoot under variable operating conditions. Finally, the results have been verified by an experimental WECS laboratory prototype. (author)

  8. Preferences for travel time variability – A study of Danish car drivers

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Rich, Jeppe

    Travel time variability (TTV) is a measure of the extent of unpredictability in travel times. It is generally accepted that TTV has a negative effect on travellers’ wellbeing and overall utility of travelling, and valuation of variability is an important issue in transport demand modelling...... preferences, to exclude non-traders, and to avoid complicated issues related to scheduled public transport services. The survey uses customised Internet questionnaires, containing a series of questions related to the traveller’s most recent morning trip to work, e.g.: • Travel time experienced on this day......, • Number of stops along the way, their duration, and whether these stops involved restrictions on time of day, • Restrictions regarding departure time from home or arrival time at work, • How often such a trip was made within the last month and the range of experienced travel times, • What the traveller...

  9. A study on bornological properties of the space of entire functions of several complex variables

    Directory of Open Access Journals (Sweden)

    Mushtaq Shaker Abdul-Hussein

    2002-12-01

    Full Text Available Spaces of entire functions of several complex variables occupy an important position in view of their vast applications in various branches of mathematics, for instance, the classical analysis, theory of approximation, theory of topological bases etc. With an idea of correlating entire functions with certain aspects in the theory of basis in locally convex spaces, we have investigated in this paper the bornological aspects of the space $X$ of integral functions of several complex variables. By $Y$ we denote the space of all power series with positive radius of convergence at the origin. We introduce bornologies on $X$ and $Y$ and prove that $Y$ is a convex bornological vector space which is the completion of the convex bornological vector space $X$.

  10. An observational study of the eclipsing nova-like variable BH Lyncis (= PG 0818 + 513)

    Science.gov (United States)

    Dhillon, V. S.; Jones, D. H. P.; Marsh, T. R.; Smith, R. C.

    1992-09-01

    We present photometric and spectroscopic observations of the novalike variable BH Lyn. The continuum and line light curves exhibit deep eclipses which recur with a period of 3.74 hr. The spectra have single-peaked Balmer and He I emission lines which exhibit a double-peaked structure near the inferior conjunction of the emission-line source. Radial velocity measurements show large phase shifts in all the emission lines. We construct light-center and Doppler maps of the system which suggest that the line emission is largely nondisk in origin. We compare and contrast BH Lyn with a number of other eclipsing novalike variables. The objects show basically the same behavior, and we conclude that the emission lines must be produced by a similar (unknown) mechanism.

  11. [Possibilities and limitations in the use of the biomathematic procedure in variability studies on man].

    Science.gov (United States)

    Peil, J

    1977-01-01

    In an anthropomorphical variability analysis the quantitative description of deterministric changes of (morphological) growth characteristics plays an important role. Working out this component of general variability and its discrimination from the random component in the measureed values underlying the quantitative analysis can be performed by biomathematical procedures. Three groups of such procedures are presented here in a survey manner. They may be employed at different levels of data processing and for quantitative description resp. mathematical modelling of the biological process in question. There are: Empirical regression, so-called internal regression, and nonlinear regression or approximation. The advantages fo employment biomathematical procedures for evaluating and interpretation of measured values of dynamical processes are sketched for the body height growth of human beings as example. But there are also mentioned limitations of application mathematical methods and procedures in the biological area.

  12. Pilot study employing heart rate variability biofeedback training to decrease anxiety in patients with eating disorders

    Science.gov (United States)

    2014-01-01

    Heart rate variability (HRV) biofeedback, a technique which encourages slow meditative breathing, was offered to 25 in-patients with various eating disorder diagnoses-anorexia nervosa, bulimia nervosa and binge eating disorder. We found that this modality had no serious side effects, and was subjectively useful to most participants. An enhanced ability to generate highly coherent HRV patterns in patients with recent onset anorexia nervosa was observed. PMID:24917934

  13. Pilot study employing heart rate variability biofeedback training to decrease anxiety in patients with eating disorders.

    Science.gov (United States)

    Scolnick, Barbara; Mostofsky, David I; Keane, Robert J

    2014-01-01

    Heart rate variability (HRV) biofeedback, a technique which encourages slow meditative breathing, was offered to 25 in-patients with various eating disorder diagnoses-anorexia nervosa, bulimia nervosa and binge eating disorder. We found that this modality had no serious side effects, and was subjectively useful to most participants. An enhanced ability to generate highly coherent HRV patterns in patients with recent onset anorexia nervosa was observed.

  14. Study of Observer Variability in Modern Display Colorimetry: An Analysis of CIE 2006 Model

    OpenAIRE

    Sarkar, Abhijit; Blonde, Laurent; Le Callet, Patrick; Autrusseau, Florent; Stauder, Jürgen; Morvan, Patrick

    2009-01-01

    International audience; CIE 2006 model presents a convenient framework for calculating the cone fundamentals, and thus the color matching functions, for various ages of an average observer. CIE 2006 model incorporates three major physiological factors affecting observer variability, namely optical densities for the ocular media absorption, macular pigment absorption, and visual pigments in the outer segments of the photoreceptors. However, it does not have a provision for a peak-wavelength sh...

  15. Optimising survey effort to monitor environmental variables: A case study using New Zealand kiwifruit orchards.

    Science.gov (United States)

    MacLeod, Catriona J; Green, Peter; Tompkins, Daniel M; Benge, Jayson; Moller, Henrik

    2016-12-01

    Environmental monitoring is increasingly used to assess spatial and temporal trends in agricultural sustainability, and test the effectiveness of farm management policies. However, detecting changes in environmental variables is often technically and logistically challenging. To demonstrate how survey effort for environmental monitoring can be optimised, we applied the new statistical power analysis R package simr to pilot survey data. Specifically, we identified the amount of survey effort required to have an 80% chance of detecting specified trends (-1 to -4% pa) in 13 environmental variables on New Zealand kiwifruit orchards within an 11-year period. The variables assessed were related to soil status, agricultural pests (birds), or ecosystem composition (birds). Analyses were conducted on average values (for each orchard and year combination) to provide a consistent scale for comparison among variables. Survey frequency varied from annual (11 surveys) to every 5 years (3 surveys). Survey size was set at either 30, 60, 150 or 300 orchards. In broad terms, we show the power to detect a specified range of trends over an 11-year period in this sector is much higher for 'soil status' than for 'agricultural pest' or 'ecosystem composition'. Changes in one subset of native bird species (nectar-feeders) requiring a particularly high level of relative survey effort to detect with confidence. Monitoring soil status can thus be smaller and less frequent than those which also want to detect changes in agricultural pests or ecosystem composition (with the latter requiring the most effort) but will depend on the magnitude of changes that is meaningful to detect. This assessment thus allows kiwifruit industry in New Zealand to optimise survey design to the desired information, and provides a template for other industries to do likewise. Power analyses are now more accessible through the provision of the simr package, so deploying and integrating them into design and decision

  16. REDUCING PROCESS VARIABILITY BY USING DMAIC MODEL: A CASE STUDY IN BANGLADESH

    OpenAIRE

    Ripon Kumar Chakrabortty; Tarun Kumar Biswas; Iraj Ahmed

    2013-01-01

    Now-a-day's many leading manufacturing industry have started to practice Six Sigma and Lean manufacturing concepts to boost up their productivity as well as quality of products. In this paper, the Six Sigma approach has been used to reduce process variability of a food processing industry in Bangladesh. DMAIC (Define,Measure, Analyze, Improve, & Control) model has been used to implement the Six Sigma Philosophy. Five phases of the model have been structured step by step respectively. Differen...

  17. A Study on the Fuzzy-Logic-Based Solar Power MPPT Algorithms Using Different Fuzzy Input Variables

    Directory of Open Access Journals (Sweden)

    Jaw-Kuen Shiau

    2015-04-01

    Full Text Available Maximum power point tracking (MPPT is one of the key functions of the solar power management system in solar energy deployment. This paper investigates the design of fuzzy-logic-based solar power MPPT algorithms using different fuzzy input variables. Six fuzzy MPPT algorithms, based on different input variables, were considered in this study, namely (i slope (of solar power-versus-solar voltage and changes of the slope; (ii slope and variation of the power; (iii variation of power and variation of voltage; (iv variation of power and variation of current; (v sum of conductance and increment of the conductance; and (vi sum of angles of arctangent of the conductance and arctangent of increment of the conductance. Algorithms (i–(iv have two input variables each while algorithms (v and (vi use a single input variable. The fuzzy logic MPPT function is deployed using a buck-boost power converter. This paper presents the details of the determinations, considerations of the fuzzy rules, as well as advantages and disadvantages of each MPPT algorithm based upon photovoltaic (PV cell properties. The range of the input variable of Algorithm (vi is finite and the maximum power point condition is well defined in steady condition and, therefore, it can be used for multipurpose controller design. Computer simulations are conducted to verify the design.

  18. Low birth weight is associated with higher blood pressure variability from childhood to young adulthood: the Bogalusa Heart Study.

    Science.gov (United States)

    Chen, Wei; Srinivasan, Sathanur R; Yao, Lu; Li, Shengxu; Dasmahapatra, Pronabesh; Fernandez, Camilo; Xu, Jihua; Berenson, Gerald S

    2012-10-01

    The association between birth weight and long-term within-individual variability of blood pressure (BP) was examined in a longitudinal cohort of 1,454 adults (939 whites and 515 blacks; adulthood age = 19-50 years) enrolled in the Bogalusa Heart Study in Bogalusa, Louisiana, in 1973-2010. BP variability was depicted as standard deviation, coefficient of variation, and deviation from age-predicted values using 6-15 serial BP measurements from childhood to adulthood over an average of 25.7 years. Birth weight was significantly and negatively associated with adulthood BP levels, long-term BP levels, and rate of change. Importantly, low birth weight was significantly associated with increased BP variability in terms of standard deviation, coefficient of variation, and deviation. As evaluated using the regression coefficients, a 1-kg lower birth weight was associated with increases in systolic BP variability measures (-0.38 mm Hg, P = 0.04 for standard deviation; -0.004 mm Hg, P = 0.01 for coefficient of variation; and -0.16 mm Hg, P = 0.04 for deviation) after adjustment for race, age, sex, mean BP levels, and gestational age; similar trends in the associations were noted for diastolic BP variability measures. In conclusion, these findings suggest that birth weight affects not only BP levels but also the magnitude of within-individual BP fluctuations over time through fetal programming in BP regulation mechanisms.

  19. Interlaboratory Study for Nickel Alloy 625 Made by Laser Powder Bed Fusion to Quantify Mechanical Property Variability

    Science.gov (United States)

    Brown, Christopher U.; Jacob, Gregor; Stoudt, Mark; Moylan, Shawn; Slotwinski, John; Donmez, Alkan

    2016-08-01

    Six different organizations participated in this interlaboratory study to quantify the variability in the tensile properties of Inconel 625 specimens manufactured using laser powder bed fusion-additive manufacturing machines. The tensile specimens were heat treated and tensile tests were conducted until failure. The properties measured were yield strength, ultimate tensile strength, elastic modulus, and elongation. Statistical analysis revealed that between-participant variability for yield strength, ultimate tensile strength, and elastic modulus values were significantly higher (up to four times) than typical within-participant variations. Only between-participant and within-participant variability were both similar for elongation. A scanning electron microscope was used to examine one tensile specimen for fractography. The fracture surface does not have many secondary cracks or other features that would reduce the mechanical properties. In fact, the features largely consist of microvoid coalescence and are entirely consistent with ductile failure.

  20. Flicker Study on Variable Speed Wind Turbines with Permanent Magnet Synchronous Generator

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Wang, Yue

    2008-01-01

    Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed in the simul......Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed...... in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated during continuous operation. The dependence of flicker emission on wind characteristics (mean speed, turbulence intensity), 3p torque oscillations due to wind shear and tower shadow effects and grid conditions (short circuit...... capacity, grid impedance angle) are analyzed. Flicker mitigation is realized by output reactive power control of the variable speed wind turbines with PMSG. Simulation results show the output reactive power control is an effective measure to mitigate the flicker during continuous operation of grid...

  1. Experimental and Numerical Study of Mild Steel Behaviour under Cyclic Loading with Variable Strain Ranges

    Directory of Open Access Journals (Sweden)

    Paulina Krolo

    2016-01-01

    Full Text Available To simulate the effect of variable strains on steel grades S275 and S355, an experimental displacement control test of plate specimens was performed. Specimens were tested under monotonic and cyclic loading according to the standard loading protocol of SAC 2000. During experimental testing, strain values were measured with an extensometer at the tapered part of the specimen. Strains obtained by the experimental tests are disproportional to the applied displacements at the ends of the specimens. This phenomenon occurs due to the imperfections of the specimen, hardening of the material, and the buckling behaviour that appears in real structures due to the high deformation experienced during earthquakes. Due to the relative simplicity and wide applicability of the Chaboche hardening model of steel, the calibration of hardening parameters based on experimental test results was conducted. For the first time, calibration of steel hardening parameters was performed following the Chaboche procedure to define the cyclic behaviour with variable strain ranges. The accuracy of the hardening model with variable strain ranges, which were simulated using ABAQUS software, was verified using the experimental results.

  2. Key Variables for Decision-Making on Urban Renewal in China: A Case Study of Chongqing

    Directory of Open Access Journals (Sweden)

    Tao Zhou

    2017-03-01

    Full Text Available Currently, the Chinese government leads urban renewal via a top-down management style with the government playing the role of decision-maker. The decision-making opinions held by groups of stakeholders are divided, which creates many social problems, project technical issues and even civil disorder. This paper uses factor analysis to extract the key variables for decision-making on urban renewal and the entropy weight method to sort these key variables by importance. Based on this order, the differing opinions of stakeholders regarding urban renewal decision-making are explored. First, contradictory opinions exist concerning the importance of the ecological environment, housing and facilities, social welfare and commercial activities, which are the main driving forces behind urban renewal, due to the groups of stakeholders having different interest demands. Second, these varying interest demands of the stakeholders affect the urban renewal decision-making results. Finally, compensation to people for the demolition of their homes, infrastructure supplements and the investment behaviour of developers display the greatest lack of consensus of all the variables tested in urban renewal decision-making between different stakeholders.

  3. A case study of alternative site response explanatory variables in Parkfield, California

    Science.gov (United States)

    Thompson, E.M.; Baise, L.G.; Kayen, R.E.; Morgan, E.C.; Kaklamanos, J.

    2011-01-01

    The combination of densely-spaced strong-motion stations in Parkfield, California, and spectral analysis of surface waves (SASW) profiles provides an ideal dataset for assessing the accuracy of different site response explanatory variables. We judge accuracy in terms of spatial coverage and correlation with observations. The performance of the alternative models is period-dependent, but generally we observe that: (1) where a profile is available, the square-root-of-impedance method outperforms VS30 (average S-wave velocity to 30 m depth), and (2) where a profile is unavailable, the topographic-slope method outperforms surficial geology. The fundamental site frequency is a valuable site response explanatory variable, though less valuable than VS30. However, given the expense and difficulty of obtaining reliable estimates of VS30 and the relative ease with which the fundamental site frequency can be computed, the fundamental site frequency may prove to be a valuable site response explanatory variable for many applications. ?? 2011 ASCE.

  4. Planning for Reliable Coal Quality Delivery Considering Geological Variability: A Case Study in Polish Lignite Mining

    Directory of Open Access Journals (Sweden)

    Wojciech Naworyta

    2015-01-01

    Full Text Available The aim of coal quality control in coal mines is to supply power plants daily with extracted raw material within certain coal quality constraints. On the example of a selected part of a lignite deposit, the problem of quality control for the run-of-mine lignite stream is discussed. The main goal is to understand potential fluctuations and deviations from production targets dependent on design options before an investment is done. A single quality parameter of the deposit is selected for this analysis—the calorific value of raw lignite. The approach requires an integrated analysis of deposit inherent variability, the extraction sequence, and the blending option during material transportation. Based on drill-hole data models capturing of spatial variability of the attribute of consideration are generated. An analysis based on two modelling approaches, Kriging and sequential Gaussian simulation, reveals advantages and disadvantages lead to conclusions about their suitability for the control of raw material quality. In a second step, based on a production schedule, the variability of the calorific value in the lignite stream has been analysed. In a third step the effect of different design options, multiple excavators and a blending bed, was investigated.

  5. Influence from genetic variability on opioid use for cancer pain: a European genetic association study of 2294 cancer pain patients

    DEFF Research Database (Denmark)

    Klepstad, P; Fladvad, T; Skorpen, F;

    2011-01-01

    Cancer pain patients need variable opioid doses. Preclinical and clinical studies suggest that opioid efficacy is related to genetic variability. However, the studies have small samples, findings are not replicated, and several candidate genes have not been studied. Therefore, a study of genetic...... mechanisms. The patients' mean age was 62.5 years, and the average pain intensity was 3.5. The patients' primary opioids were morphine (n=830), oxycodone (n=446), fentanyl (n=699), or other opioids (n=234). Pain intensity, time on opioids, age, gender, performance status, and bone or CNS metastases predicted......C, HTR3D, HTR3E, HTR1, or CNR1 showed significant associations with opioid dose in both the development and the validation analyzes. These findings do not support the use of pharmacogenetic analyses for the assessed SNPs to guide opioid treatment. The study also demonstrates the importance...

  6. Heart rate variability biofeedback in patients with alcohol dependence: a randomized controlled study

    Directory of Open Access Journals (Sweden)

    Penzlin AI

    2015-10-01

    Full Text Available Ana Isabel Penzlin,1 Timo Siepmann,2 Ben Min-Woo Illigens,3 Kerstin Weidner,4 Martin Siepmann4 1Institute of Clinical Pharmacology, 2Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Saxony, Germany; 3Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; 4Department of Psychotherapy and Psychosomatic Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Saxony, Germany Background and objective: In patients with alcohol dependence, ethyl-toxic damage of vasomotor and cardiac autonomic nerve fibers leads to autonomic imbalance with neurovascular and cardiac dysfunction, the latter resulting in reduced heart rate variability (HRV. Autonomic imbalance is linked to increased craving and cardiovascular mortality. In this study, we sought to assess the effects of HRV biofeedback training on HRV, vasomotor function, craving, and anxiety. Methods: We conducted a randomized controlled study in 48 patients (14 females, ages 25–59 years undergoing inpatient rehabilitation treatment. In the treatment group, patients (n=24 attended six sessions of HRV biofeedback over 2 weeks in addition to standard rehabilitative care, whereas, in the control group, subjects received standard care only. Psychometric testing for craving (Obsessive Compulsive Drinking Scale, anxiety (Symptom Checklist-90-Revised, HRV assessment using coefficient of variation of R-R intervals (CVNN analysis, and vasomotor function assessment using laser Doppler flowmetry were performed at baseline, immediately after completion of treatment or control period, and 3 and 6 weeks afterward (follow-ups 1 and 2. Results: Psychometric testing showed decreased craving in the biofeedback group immediately postintervention (OCDS scores: 8.6±7.9 post-biofeedback versus 13.7±11.0 baseline [mean ± standard deviation], P<0.05, whereas craving was unchanged at

  7. A comprehensive long-term study of the radio and X-ray variability of NGC 4051 Paper II

    Science.gov (United States)

    Jones, S.; McHardy, I.; Maccarone, T. J.

    2017-02-01

    The origin of the low-luminosity radio emission in radio-quiet active galactic nucleus, is unknown. The detection of a positive correlation between the radio and X-ray emission would imply a jet-like origin, similar to that seen in 'hard-state' X-ray binary systems. In our previous work, we found no believable radio variability in the well-known X-ray bright Seyfert 1 galaxy NGC 4051, despite large amplitude X-ray variability. In this study, we have carefully re-analysed radio and X-ray observations using the same methods as our previous work; we again find no evidence for core radio variability. In direct contrast to our findings, another study claim significant radio variability and a distinctive anticorrelation between radio and X-ray data for the same source. The other study report only integral flux values and do not consider the effect of the changing array on the synthesized beam. In both our studies of NGC 4051, we have taken great care to account for the effect that the changing beam size has on the measured radio flux and as a result we are confident that our method gives more accurate values for the intrinsic core radio flux. However, the lack of radio variability we find is hard to reconcile because radio images of NGC 4051 do show jet-like structure. We suggest that the radio structures observed are likely the result of a previous period of higher radio activity and that the current level of radio emission from a compact nuclear jet is low.

  8. A Study of the Groundwater Level Spatial Variability in the Messara Valley of Crete

    Science.gov (United States)

    Varouchakis, E. A.; Hristopulos, D. T.; Karatzas, G. P.

    2009-04-01

    The island of Crete (Greece) has a dry sub-humid climate and marginal groundwater resources, which are extensively used for agricultural activities and human consumption. The Messara valley is located in the south of the Heraklion prefecture, it covers an area of 398 km2, and it is the largest and most productive valley of the island. Over-exploitation during the past thirty (30) years has led to a dramatic decrease of thirty five (35) meters in the groundwater level. Possible future climatic changes in the Mediterranean region, potential desertification, population increase, and extensive agricultural activity generate concern over the sustainability of the water resources of the area. The accurate estimation of the water table depth is important for an integrated groundwater resource management plan. This study focuses on the Mires basin of the Messara valley for reasons of hydro-geological data availability and geological homogeneity. The research goal is to model and map the spatial variability of the basin's groundwater level accurately. The data used in this study consist of seventy (70) piezometric head measurements for the hydrological year 2001-2002. These are unevenly distributed and mostly concentrated along a temporary river that crosses the basin. The range of piezometric heads varies from an extreme low value of 9.4 meters above sea level (masl) to 62 masl, for the wet period of the year (October to April). An initial goal of the study is to develop spatial models for the accurate generation of static maps of groundwater level. At a second stage, these maps should extend the models to dynamic (space-time) situations for the prediction of future water levels. Preliminary data analysis shows that the piezometric head variations are not normally distributed. Several methods including Box-Cox transformation and a modified version of it, transgaussian Kriging, and Gaussian anamorphosis have been used to obtain a spatial model for the piezometric head. A

  9. Relationship Between Malocclusion And Behavioral, Demographic And Socioeconomic Variables: A Cross-sectional Study Of 5-year-olds.

    OpenAIRE

    Hebling S.R.; Cortellazzi K.L.; Tagliaferro E.P.; Hebling E.; Ambrosano G.M.; Meneghim M.C.; Pereira A.C.

    2008-01-01

    OBJECTIVE: Epidemiological studies have demonstrated that the prevalence and the severity of malocclusion have increased over the years. The aim of this study was to evaluate the relationship between malocclusions, such as open bite and crossbite, and behavioral, demographic and socioeconomic variables in a sample of 5-year-old children attending preschools. METHODS: The random sample consisted of 728 preschool children attending 22 public (n = 428) and 18 private (n = 300) preschools. A cali...

  10. Variability in the management of nonvariceal upper gastrointestinal bleeding in Europe: an observational study.

    Science.gov (United States)

    Lanas, Angel; Aabakken, Lars; Fonseca, Jorge; Mungan, Zeynel; Papatheodoridis, George; Piessevaux, Hubert; Rotondano, Gianluca; Nuevo, Javier; Tafalla, Monica

    2012-12-01

    Despite recent advances in endoscopic and pharmacological management, nonvariceal upper gastrointestinal bleeding (NVUGIB) is still associated with considerable mortality and morbidity that vary between countries. The European Survey of Nonvariceal Upper Gastrointestinal Bleeding (ENERGiB) reported clinical outcomes across Europe (Belgium, Greece, Italy, Norway, Portugal, Spain, and Turkey) and evaluated management strategies in a "real-world" European setting. This article presents the differences in clinical management strategies among countries participating in ENERGiB. Adult patients consecutively presenting with overt NVUGIB at 123 participating hospitals over a 2-month period were included. Data relevant to the initial NVUGIB episode and for up to 30 days afterwards were collected retrospectively from patient medical records. The number of evaluable patients was 2,660; patient demographics and clinical characteristics were similar across countries. There was wide between-country variability in the area and speciality of the NVUGIB management team and unit transfer rates after the initial hospital assessment. The mean time from admission to endoscopy was <1 day only in Italy and Spain. Wide variation in the use of preendoscopy (35.0-88.7%) and relatively consistent (86.5-96.0%) postendoscopic pharmacological therapy rates were observed. There was substantial by-country variability in the rate of therapeutic procedures performed during endoscopy (24.9-47.6%). NVUGIB-related healthcare resource consumption was high and variable (days hospitalized, mean 5.4-8.7 days; number of endoscopies during hospitalization, mean 1.1-1.7). ENERGiB demonstrates that there are substantial differences in the management of patients with acute NVUGIB episodes across Europe, and that in many cases the guideline recommendations for the management of NVUGIB are not being followed.

  11. A study of long-term sea level variability in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    XU Ying; LIN Mingsen; ZHENG Quanan; YE Xiaomin; LI Junyi; ZHU Benlu

    2015-01-01

    From the analyses of the satellite altimeter Maps of Sea Level Anomaly (MSLA) data, tidal gauge sea level data and historical sea level data, this paper investigates the long-term sea level variability in the East China Sea (ECS). Based on the correlation analysis, we calculate the correlation coefficient between tidal gauge and the closest MSLA grid point, then generate the map of correlation coefficient of the entire ECS. The results show that the satellite altimeter MSLA data is effective to observe coastal sea level variability. An important finding is that from map of correlation coefficient we can identify the Kuroshio. The existence of Kuroshio decreases the correlation between coastal and the Pacific sea level. Kurishio likes a barrier or a wall, which blocks the effect of the Pacific and the global change. Moreover, coastal sea level in the ECS is mainly associated with local systems rather than global change. In order to calculate the long-term sea level variability trend, the empirical mode decomposition (EMD) method is applied to derive the trend on each MSLA grid point in the entire ECS. According to the 2-D distribution of the trend and rising rate, the sea level on the right side of the axis of Kuroshio rise faster than in its left side. This result supports the barrier effect of Kuroshio in the ECS. For the entire ECS, the average sea level rose 45.0 mm between 1993 and 2010, with a rising rate of (2.5±0.4) mm/a which is slower than global average. The relatively slower sea level rising rate further proves that sea level rise in the ECS has less response to global change due to its own local system effect.

  12. Climatic variability, plasticity, and dispersal: A case study from Lake Tana, Ethiopia.

    Science.gov (United States)

    Grove, Matt; Lamb, Henry; Roberts, Helen; Davies, Sarah; Marshall, Mike; Bates, Richard; Huws, Dei

    2015-10-01

    The numerous dispersal events that have occurred during the prehistory of hominin lineages are the subject of longstanding and increasingly active debate in evolutionary anthropology. As well as research into the dating and geographic extent of such dispersals, there is an increasing focus on the factors that may have been responsible for dispersal. The growing body of detailed regional palaeoclimatic data is invaluable in demonstrating the often close relationship between changes in prehistoric environments and the movements of hominin populations. The scenarios constructed from such data are often overly simplistic, however, concentrating on the dynamics of cyclical contraction and expansion during severe and ameliorated conditions respectively. This contribution proposes a two-stage hypothesis of hominin dispersal in which populations (1) accumulate high levels of climatic tolerance during highly variable climatic phases, and (2) express such heightened tolerance via dispersal in subsequent low-variability phases. Likely dispersal phases are thus proposed to occur during stable climatic phases that immediately follow phases of high climatic variability. Employing high resolution palaeoclimatic data from Lake Tana, Ethiopia, the hypothesis is examined in relation to the early dispersal of Homo sapiens out of East Africa and into the Levant. A dispersal phase is identified in the Lake Tana record between c. 112,550 and c. 96,975 years ago, a date bracket that accords well with the dating evidence for H. sapiens occupation at the sites of Qafzeh and Skhul. Results are discussed in relation to the complex pattern of H. sapiens dispersal out of East Africa, with particular attention paid to the implications of recent genetic chronologies for the origin of non-African modern humans. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Parallax of a Mira variable R Ursae Majoris studied with astrometric VLBI

    Science.gov (United States)

    Nakagawa, Akiharu; Kurayama, Tomoharu; Matsui, Makoto; Omodaka, Toshihiro; Honma, Mareki; Shibata, Katsunori M.; Sato, Katsuhisa; Jike, Takaaki

    2016-10-01

    We have measured an annual parallax of the Mira variable R Ursae Majoris (R UMa) with the VLBI Exploration for Radio Astronomy (VERA). From the monitoring VLBI observations over a span of about two years, we detected H2O maser spots in the LSR velocity range from 37 to 42 km s-1. We derived an annual parallax of 1.97 ± 0.05 mas, and this gives a corresponding distance of 508 ± 13 pc. The VLBI maps revealed 72 maser spots distributed in an ˜110 au area around the expected stellar position. Circumstellar kinematics of the maser spots were also revealed by subtracting a systemic motion in the Hipparcos catalog from proper motions of each maser spot derived from our VLBI observations. Infrared photometry was also conducted to measure a K-band apparent magnitude, and we obtained a mean magnitude of mK = 1.19 ± 0.02 mag. Using the trigonometric distance, mK is converted to a K-band absolute magnitude of MK = -7.34 ± 0.06 mag. This result gives a much more accurate absolute magnitude for R UMa than previously provided. We solved a zero-point of the MK-log P relation for the Galactic Mira variables and obtained a relation of MK = -3.52 log P + (1.09 ± 0.14). Other long-period variables, including red supergiants, whose distances were determined with astrometric VLBI, were also compiled to explore the different sequences of the MK-log P relation.

  14. Preliminary study of the individual variability of the sexual receptivity of rabbit does

    Directory of Open Access Journals (Sweden)

    M. Theau.Clément

    2015-09-01

    Full Text Available The aim of this preliminary experiment was to investigate the individual variability of the sexual receptivity of a rabbit doe in the presence of a buck (lordosis position, 0-1  variable. Twenty primiparous does maintained without reproduction were tested over 4 mo (3 tests per week at a 2- or 3-day interval after their first kindling. Out of 48 tests, the receptivity rate was 52.5±50.0% on average and varied from 20.0 to 73.3% depending on the test day. The does were lactating at the beginning of the test period and a strong receptivity decrease was revealed at the peak of lactation. Receptivity did not vary according to the tester buck or to the test operator. The individual receptivity of does varied from 8.6 to 81.3%; three of them had a receptivity rate lower than 30% and four of them a receptivity rate greater than 70%. No relationship was revealed between average receptivity and body weight or body weight variations around first litter weaning. The repeatability of sexual receptivity of non-lactating does was 23.2%. Lowly receptive does had a shorter average oestrus time (<2 tests and a longer dioestrus time (≥6 tests, whereas highly receptive does had a longer oestrus time (>4 tests and a shorter dioestrus time (≤3 tests. The correlation between average receptivity and average oestrus time was 0.80. These results indicate a fairly high individual variability of the expression of rabbit sexual receptivity and of its duration, and justify the exploration of an eventual genetic origin in a subsequent experiment.

  15. Age-Based Methods to Explore Time-Related Variables in Occupational Epidemiology Studies

    Energy Technology Data Exchange (ETDEWEB)

    Janice P. Watkins, Edward L. Frome, Donna L. Cragle

    2005-08-31

    Although age is recognized as the strongest predictor of mortality in chronic disease epidemiology, a calendar-based approach is often employed when evaluating time-related variables. An age-based analysis file, created by determining the value of each time-dependent variable for each age that a cohort member is followed, provides a clear definition of age at exposure and allows development of diverse analytic models. To demonstrate methods, the relationship between cancer mortality and external radiation was analyzed with Poisson regression for 14,095 Oak Ridge National Laboratory workers. Based on previous analysis of this cohort, a model with ten-year lagged cumulative radiation doses partitioned by receipt before (dose-young) or after (dose-old) age 45 was examined. Dose-response estimates were similar to calendar-year-based results with elevated risk for dose-old, but not when film badge readings were weekly before 1957. Complementary results showed increasing risk with older hire ages and earlier birth cohorts, since workers hired after age 45 were born before 1915, and dose-young and dose-old were distributed differently by birth cohorts. Risks were generally higher for smokingrelated than non-smoking-related cancers. It was difficult to single out specific variables associated with elevated cancer mortality because of: (1) birth cohort differences in hire age and mortality experience completeness, and (2) time-period differences in working conditions, dose potential, and exposure assessment. This research demonstrated the utility and versatility of the age-based approach.

  16. Age-Based Methods to Explore Time-Related Variables in Occupational Epidemiology Studies

    Energy Technology Data Exchange (ETDEWEB)

    Janice P. Watkins, Edward L. Frome, Donna L. Cragle

    2005-08-31

    Although age is recognized as the strongest predictor of mortality in chronic disease epidemiology, a calendar-based approach is often employed when evaluating time-related variables. An age-based analysis file, created by determining the value of each time-dependent variable for each age that a cohort member is followed, provides a clear definition of age at exposure and allows development of diverse analytic models. To demonstrate methods, the relationship between cancer mortality and external radiation was analyzed with Poisson regression for 14,095 Oak Ridge National Laboratory workers. Based on previous analysis of this cohort, a model with ten-year lagged cumulative radiation doses partitioned by receipt before (dose-young) or after (dose-old) age 45 was examined. Dose-response estimates were similar to calendar-year-based results with elevated risk for dose-old, but not when film badge readings were weekly before 1957. Complementary results showed increasing risk with older hire ages and earlier birth cohorts, since workers hired after age 45 were born before 1915, and dose-young and dose-old were distributed differently by birth cohorts. Risks were generally higher for smokingrelated than non-smoking-related cancers. It was difficult to single out specific variables associated with elevated cancer mortality because of: (1) birth cohort differences in hire age and mortality experience completeness, and (2) time-period differences in working conditions, dose potential, and exposure assessment. This research demonstrated the utility and versatility of the age-based approach.

  17. A scalable and portable framework for massively parallel variable selection in genetic association studies.

    Science.gov (United States)

    Chen, Gary K

    2012-03-01

    The deluge of data emerging from high-throughput sequencing technologies poses large analytical challenges when testing for association to disease. We introduce a scalable framework for variable selection, implemented in C++ and OpenCL, that fits regularized regression across multiple Graphics Processing Units. Open source code and documentation can be found at a Google Code repository under the URL http://bioinformatics.oxfordjournals.org/content/early/2012/01/10/bioinformatics.bts015.abstract. Supplementary data are available at Bioinformatics online.

  18. Observational studies of cataclysmic variable evolution: Of samples, biases and surprises

    Directory of Open Access Journals (Sweden)

    B.T. Gansicke

    2004-01-01

    Full Text Available Presento un breve informe sobre el estado de tres grandes proyectos observacionales destinados a veri car nuestra actual comprensi on de la evoluci on de variables catacl smicas (CVs: la selecci on espectrosc opica de las nuevas CVs en el Hamburg Quasar Survey, la b usqueda de pre-CVs bas andose en los colores de Sloan y en la espectroscop a multi-objeto UK Schmidt/6dF y la identi caci on de CVs que proceden de binarias de rayos X supersuaves, utilizando el \\survey" espectrosc opico en el ultravioleta lejano del HST/STIS.

  19. Observational studies of cataclysmic variable evolution: Of samples, biases and surprises

    OpenAIRE

    Gansicke, B. T.

    2004-01-01

    Presento un breve informe sobre el estado de tres grandes proyectos observacionales destinados a veri car nuestra actual comprensi on de la evoluci on de variables catacl smicas (CVs): la selecci on espectrosc opica de las nuevas CVs en el Hamburg Quasar Survey, la b usqueda de pre-CVs bas andose en los colores de Sloan y en la espectroscop a multi-objeto UK Schmidt/6dF y la identi caci on de CVs que proceden de binarias de rayos X supersuaves, utilizando el \\survey" espectrosc ...

  20. Variability of cork from Portuguese Quercus suber studied by solid-state (13)C-NMR and FTIR spectroscopies.

    Science.gov (United States)

    Lopes, M H; Barros, A S; Pascoal Neto, C; Rutledge, D; Delgadillo, I; Gil, A M

    2001-01-01

    A new approach is presented for the study of the variability of Portuguese reproduction cork using solid-state (13)C-NMR spectroscopy and photoacoustic (PAS) FTIR (FTIR-PAS) spectroscopy combined with chemometrics. Cork samples were collected from 12 different geographical sites, and their (13)C-cross-polarization with magic angle spinning (CP/MAS) and FTIR spectra were registered. A large spectral variability among the cork samples was detected by principal component analysis and found to relate to the suberin and carbohydrate contents. This variability was independent of the sample geographical origin but significantly dependent on the cork quality, thus enabling the distinction of cork samples according to the latter property. The suberin content of the cork samples was predicted using multivariate regression models based on the (13)C-NMR and FTIR spectra of the samples as reported previously. Finally, the relationship between the variability of the (13)C-CP/MAS spectra with that of the FTIR-PAS spectra was studied by outer product analysis. This type of multivariate analysis enabled a clear correlation to be established between the peaks assigned to suberin and carbohydrate in the FTIR spectrum and those appearing in the (13)C-CP/MAS spectra.

  1. Spatiotemporal Variability of Surface Meteorological Variables During Fog and No-Fog Events in the Heber Valley, UT; Selected Case Studies From MATERHORN-Fog

    Science.gov (United States)

    van den Bossche, Michael; De Wekker, Stephan F. J.

    2016-09-01

    We investigated the spatiotemporal variability of surface meteorological variables in the nocturnal boundary layer using six automatic weather stations deployed in the Heber Valley, UT, during the MATERHORN-Fog experiment. The stations were installed on the valley floor within a 1.5 km × 0.8 km area and collected 1-Hz wind and pressure data and 0.2-Hz temperature and humidity data. We describe the weather stations and analyze the spatiotemporal variability of the measured variables during three nights with radiative cooling. Two nights were characterized by the presence of dense ice fog, one night with a persistent (`heavy') fog, and one with a short-lived (`moderate') fog, while the third night had no fog. Frost-point depressions were larger preceding the night without fog and showed a continued decrease during the no-fog night. On both fog nights, the frost-point depression reached values close to zero early in the night, but ~5 h earlier on the heavy-fog night than on the moderate-fog night. Spatial variability of temperature and humidity was smallest during the heavy-fog night and increased temporarily during short periods when wind speeds increased and the fog lifted. During all three nights, wind speeds did not exceed 2 m/s. The temporal variability of the wind speed and direction was larger during the fog nights than during the no-fog nights, but was particularly large during the heavy-fog night. The large variability corresponded with short-lived (5-10 min) pressure variations with amplitudes on the order of 0.5 hPa, indicating gravity wave activity. These pressure fluctuations occurred at all stations and were correlated in particular with variability in wind direction. Although not able to provide a complete picture of the nocturnal boundary layer, our low-cost weather stations were able to continuously collect data that were comparable to those of nearby research-grade instruments. From these data, we distinguished between fog and no-fog events

  2. Nong Thale Pron - a key site from southern Thailand for studying monsoon variability during the past 15000 years

    Science.gov (United States)

    Bredberg, Camilla; Chawchai, Sakonvan; Chabangborn, Akkaneewut; Kylander, Malin; Fritz, Sherilyn; Reimer, Paula J.; Wohlfarth, Barbara

    2014-05-01

    Studies of marine sediments, cave speleothemes, annually laminated corals, and tree rings from Asian monsoon regions have added knowledge to our understanding of the factors that control inter-annual to millennial monsoon variability in the past and have provided important constraints for climate modeling scenarios. In contrast, the spatial and temporal pattern of sub-millennial scale monsoon variability and its impact on land cover in SE Asia are still unresolved. This shortcoming stems from the fact that temporally well-resolved paleo-environmental studies are missing from large parts of SE Asia, especially from Thailand. Given that global and regional climate models are increasingly using terrestrial paleo- data to test their performance, past changes in land cover are therefore important variables to better understand feedbacks between different Earth systems. We obtained sediments from Lake Nong Thale Pron, in southern Thailand (8º 10`N, 99 º23`E; 380 m.asl). The aim of our study is to reconstruct lake status changes and to evaluate whether the extent of these changes are linked to known shifts in monsoon intensity and variability. Preliminary results show that lake infilling started more than 15,000 years ago and that the sediments cover the last deglaciation and the Holocene. Current analyses include Itrax XRF core scanning, loss-on-ignition (LOI at 950 and 550ºC), CN elemental and isotopic composition. We expect that our results will be able to give a picture of how the lake's status has changed over time and whether the extent of these changes is linked to known shifts in monsoon intensity and variability.

  3. Laboratory Studies of the Effects of Static and Variable Magnetic Fields on Freshwater Fish

    Energy Technology Data Exchange (ETDEWEB)

    Cada, Glenn F [ORNL; Bevelhimer, Mark S [ORNL; Fortner, Allison M [ORNL; Riemer, Kristina P [ORNL; Schweizer, Peter E [ORNL

    2012-04-01

    ). Those experiments found little indication that the behaviors of these freshwater species were altered by the static magnetic fields that would be created by submerged, direct current (DC)-transmitting electrical cables expected to be used by the HK developers. Laboratory experiments in FY 2011 examined the responses of additional fish species (sunfish, striped bass, and channel catfish) to the static magnetic fields. In addition, the effects of variable magnetic fields (that would be created by the HK generators and AC-transmitting cables) on swimming behavior of two electrosensitive fish species (paddlefish and lake sturgeon) were studied.

  4. Study of orbital and superorbital variability of LSI +61° 303 with X-ray data

    Science.gov (United States)

    Chernyakova, M.; Babyk, Iu.; Malyshev, D.; Vovk, Ie.; Tsygankov, S.; Takahashi, H.; Fukazawa, Ya.

    2017-09-01

    LSI +61° 303 is one of the few X-ray binaries with a Be star companion from which radio, X-rays and high-energy gamma-ray (GeV and TeV) emission have been observed. The nature of the high-energy activity of the system is not yet fully understood, but it is widely believed that it is generated due to the interaction of the relativistic electrons leaving the compact object with the photons and non-relativistic wind of the Be star. The superorbital variability of the system has been observed in the radio, optical and X-ray domains and could be due to the cyclic change of the Be star disc size. In this paper, we systematically review all publicly available data from Suzaku, XMM-Newton, Chandra and Swift observatories in order to measure the absorption profile of the circumstellar Be disc as a function of orbital and superorbital phases. We also discuss short-term variability of the system, found during the analysis and its implications for the understanding of the physical processes in this system.

  5. New Quasar Surveys with WIRO: Data and Calibration for Studies of Variability

    Science.gov (United States)

    Lyke, Bradley; Bassett, Neil; Deam, Sophie; Dixon, Don; Griffith, Emily; Harvey, William; Lee, Daniel; Haze Nunez, Evan; Parziale, Ryan; Witherspoon, Catherine; Myers, Adam D.; Findlay, Joseph; Kobulnicky, Henry A.; Dale, Daniel A.

    2017-01-01

    Measurements of quasar variability offer the potential for understanding the physics of accretion processes around supermassive black holes. However, generating structure functions in order to characterize quasar variability can be observationally taxing as it requires imaging of quasars over a large variety of date ranges. To begin to address this problem, we have conducted an imaging survey of sections of Sloan Digital Sky Survey (SDSS) Stripe 82 at the Wyoming Infrared Observatory (WIRO). We used standard stars to calculate zero-point offsets between WIRO and SDSS observations in the urgiz magnitude system. After finding the zero-point offset, we accounted for further offsets by comparing standard star magnitudes in each WIRO frame to coadded magnitudes from Stripe 82 and applying a linear correction. Known (i.e. spectroscopically confirmed) quasars at the epoch we conducted WIRO observations (Summer, 2016) and at every epoch in SDSS Stripe 82 (~80 total dates) were hence calibrated to a similar magnitude system. The algorithm for this calibration compared 1500 randomly selected standard stars with an MJD within 0.07 of the MJD of each quasar of interest, for each of the five ugriz filters. Ultimately ~1000 known quasars in Stripe 82 were identified by WIRO and their SDSS-WIRO magnitudes were calibrated to a similar scale in order to generate ensemble structure functions.This work is supported by the National Science Foundation under REU grant AST 1560461.

  6. Radio to gamma-ray variability study of blazar S5 0716+714

    CERN Document Server

    Rani, B; Fuhrmann, L; Boettcher, M; Lott, B; Aller, H D; Aller, M F; Angelakis, E; Bach, U; Bastieri, D; Falcone, A D; Fukazawa, Y; Gabanyi, K E; Gupta, A C; Gurwell, M; Itoh, R; Kawabata, K S; Krips, M; Lähteenmäki, A A; Liu, X; Marchili, N; Max-Moerbeck, W; Nestoras, I; Nieppola, E; Quintana-Lacaci, G; Readhead, A C S; Richards, J L; Sasada, M; Sievers, A; Sokolovsky, K; Stroh, M; Tammi, J; Tornikoski, M; Uemura, M; Ungerechts, H; Urano, T; Zensus, J A

    2013-01-01

    We present the results of a series of radio, optical, X-ray and gamma-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multi-frequency observations were obtained using several ground and space based facilities. The intense optical monitoring of the source reveals faster repetitive variations superimposed on a long-term variability trend at a time scale of ~350 days. Episodes of fast variability recur on time scales of ~ 60-70 days. The intense and simultaneous activity at optical and gamma-ray frequencies favors the SSC mechanism for the production of the high-energy emission. Two major low-peaking radio flares were observed during this high optical/gamma-ray activity period. The radio flares are characterized by a rising and a decaying stage and are in agreement with the formation of a shock and its evolution. We found that the evolution of the radio flares requires a geometrical variation in addition to intrinsic variations of the source. Different estima...

  7. Structural studies on Mycobacterium tuberculosis RecA: Molecular plasticity and interspecies variability

    Indian Academy of Sciences (India)

    Anu V Chandran; J Rajan Prabu; Astha Nautiyal; K Neelakanteshwar Patil; K Muniyappa; M Vijayan

    2015-03-01

    Structures of crystals of Mycobacterium tuberculosis RecA, grown and analysed under different conditions, provide insights into hitherto underappreciated details of molecular structure and plasticity. In particular, they yield information on the invariant and variable features of the geometry of the P-loop, whose binding to ATP is central for all the biochemical activities of RecA. The strengths of interaction of the ligands with the P-loop reveal significant differences. This in turn affects the magnitude of the motion of the `switch’ residue, Gln195 in M. tuberculosis RecA, which triggers the transmission of ATP-mediated allosteric information to the DNA binding region. M. tuberculosis RecA is substantially rigid compared with its counterparts from M. smegmatis and E. coli, which exhibit concerted internal molecular mobility. The interspecies variability in the plasticity of the two mycobacterial proteins is particularly surprising as they have similar sequence and 3D structure. Details of the interactions of ligands with the protein, characterized in the structures reported here, could be useful for design of inhibitors against M. tuberculosis RecA.

  8. Comparative Study on Response Surfaces for Reliability Analysis of Spatially Variable Soil Slope

    Institute of Scientific and Technical Information of China (English)

    李亮; 褚雪松

    2015-01-01

    This paper focuses on the performance of the second-order polynomial-based response surfaces on the reliability of spatially variable soil slope. A single response surface constructed to approximate the slope system failure performance functionG(X) (called single RS) and multiple response surfaces constructed on finite number of slip surfaces (called multiple RS) are developed, respectively. Single RS and multiple RS are applied to evaluate the system failure probability pf for a cohesive soil slope together with Monte Carlo simulation (MCS). It is found thatpf calculated by single RS deviates significantly from that obtained by searching a large number of potential slip surfaces, and this deviation becomes insignificant with the decrease of the number of random variables or the increase of the scale of fluctuation. In other words, single RS cannot approximateG(X) with reasonable accuracy. The value ofpf from multiple response surfaces fits well with that obtained by searching a large number of potential slip surfaces. That is, multiple RS can estimateG(X) with reasonable accuracy.

  9. Combating unmeasured confounding in cross-sectional studies: evaluating instrumental-variable and Heckman selection models.

    Science.gov (United States)

    DeMaris, Alfred

    2014-09-01

    Unmeasured confounding is the principal threat to unbiased estimation of treatment "effects" (i.e., regression parameters for binary regressors) in nonexperimental research. It refers to unmeasured characteristics of individuals that lead them both to be in a particular "treatment" category and to register higher or lower values than others on a response variable. In this article, I introduce readers to 2 econometric techniques designed to control the problem, with a particular emphasis on the Heckman selection model (HSM). Both techniques can be used with only cross-sectional data. Using a Monte Carlo experiment, I compare the performance of instrumental-variable regression (IVR) and HSM to that of ordinary least squares (OLS) under conditions with treatment and unmeasured confounding both present and absent. I find HSM generally to outperform IVR with respect to mean-square-error of treatment estimates, as well as power for detecting either a treatment effect or unobserved confounding. However, both HSM and IVR require a large sample to be fully effective. The use of HSM and IVR in tandem with OLS to untangle unobserved confounding bias in cross-sectional data is further demonstrated with an empirical application. Using data from the 2006-2010 General Social Survey (National Opinion Research Center, 2014), I examine the association between being married and subjective well-being.

  10. Weekly variability of precipitation induced by anthropogenic aerosols: A case study in Korea in summer 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Soo Ya; Jeong, Jaein I.; Park, R.; Lim, Kyo-Sun; Hong, Song-You

    2016-01-06

    We examine the effect of anthropogenic aerosols on the weekly variability of precipitation in Korea in summer 2004 by using Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models. We con-duct two WRF simulations including a baseline simulation with empirically based cloud condensation nuclei (CCN) number concentrations and a sensitivity simulation with our implementation to account for the effect of aerosols on CCN number concentrations. The first simulation underestimates observed precipitation amounts, particularly in northeastern coastal areas of Korea, whereas the latter shows higher precipitation amounts that are in better agree-ment with the observations. In addition, the sensitivity model with the aerosol effects reproduces the observed weekly variability, particularly for precipitation frequency with a high R at 0.85, showing 20% increase of precipita-tion events during the weekend than those during weekdays. We find that the aerosol effect results in higher CCN number concentrations during the weekdays and a three-fold increase of the cloud water mixing ratio through en-hanced condensation. As a result, the amount of warm rain is generally suppressed because of the low auto-conversion process from cloud water to rain water under high aerosol conditions. The inefficient conversion, how-ever, leads to higher vertical development of clouds in the mid-atmosphere with stronger updrafts in the sensitivity model, which increases by 21% cold-phase hydrometeors including ice, snow, and graupel relative to the baseline model and ultimately results in higher precipitation amounts in summer.

  11. The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

    CERN Document Server

    Aleksić, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; de Almeida, U Barres; Barrio, J A; González, J Becerra; Bednarek, W; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T

    2015-01-01

    We performed a 4.5-month multi-instrument campaign (from radio to VHE gamma rays) on Mrk421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-corre...

  12. Photometric study of selected cataclysmic variables II. Time-series photometry of nine systems

    CERN Document Server

    Papadaki, C; Stanishev, V; Boumis, P; Akras, S; Sterken, C

    2008-01-01

    We present time-series photometry of nine cataclysmic variables: EI UMa, V844Her, V751 Cyg, V516 Cyg, GZ Cnc, TY Psc, V1315 Aql, ASAS J002511+1217.12, V1315 Aql and LN UMa. The observations were conducted at various observatories, covering 170 hours and comprising 7,850 data points in total. For the majority of targets we confirm previously reported periodicities and for some of them we give, for the first time, their spectroscopic orbital periods. For those dwarf-nova systems which we observed during both quiescence and outburst, the increase in brightness was followed by a decrease in the amount of flickering. Quasi-periodic oscillations have either been discovered, or were confirmed. For the eclipsing system V1315 Aql we have covered 9 eclipses, and obtained a refined orbital ephemeris. We find that, during its long baseline of observations, no change in the orbital period of this system has occurred. V1315 Aql also shows eclipses of variable depth.

  13. Canalization effect in the coagulation cascade and the interindividual variability of oral anticoagulant response. a simulation Study

    Directory of Open Access Journals (Sweden)

    Corlan Alexandru D

    2011-10-01

    Full Text Available Abstract Background Increasing the predictability and reducing the rate of side effects of oral anticoagulant treatment (OAT requires further clarification of the cause of about 50% of the interindividual variability of OAT response that is currently unaccounted for. We explore numerically the hypothesis that the effect of the interindividual expression variability of coagulation proteins, which does not usually result in a variability of the coagulation times in untreated subjects, is unmasked by OAT. Results We developed a stochastic variant of the Hockin-Mann model of the tissue factor coagulation pathway, using literature data for the variability of coagulation protein levels in the blood of normal subjects. We simulated in vitro coagulation and estimated the Prothrombin Time and the INR across a model population. In a model of untreated subjects a "canalization effect" can be observed in that a coefficient of variation of up to 33% of each protein level results in a simulated INR of 1 with a clinically irrelevant dispersion of 0.12. When the mean and the standard deviation of vitamin-K dependent protein levels were reduced by 80%, corresponding to the usual Warfarin treatment intensity, the simulated INR was 2.98 ± 0.48, a clinically relevant dispersion, corresponding to a reduction of the canalization effect. Then we combined the Hockin-Mann stochastic model with our previously published model of population response to Warfarin, that takes into account the genetical and the phenotypical variability of Warfarin pharmacokinetics and pharmacodynamics. We used the combined model to evaluate the coagulation protein variability effect on the variability of the Warfarin dose required to reach an INR target of 2.5. The dose variance when removing the coagulation protein variability was 30% lower. The dose was mostly related to the pretreatment levels of factors VII, X, and the tissue factor pathway inhibitor (TFPI. Conclusions It may be worth

  14. Kinetic of conversion of hemicellulose hexose to 5-hydroxymethylfurfural%半纤维素六碳糖转化为5-羟甲基糠醛的动力学

    Institute of Scientific and Technical Information of China (English)

    陈景平; 孙武星; 林海周; 茹斌; 赵源; 王树荣

    2016-01-01

    选取甘露糖和半乳糖两种典型半纤维素六碳糖作为模化物,考察其在水相中较宽温度(100~200℃)和时间(10~240min)范围内的降解行为。实验结果表明,较高的反应温度能提高六碳糖的转化率和5-羟甲基糠醛(HMF)的产率;在200℃时甘露糖和半乳糖生成的HMF最高产率分别为26.82%和22.86%,乙酰丙酸(LA)的产率低于3%;半乳糖因容易异构化生成塔格糖而非果糖,导致其HMF产率较低。采用六碳糖平行生成HMF和Humin,随后HMF平行生成的LA和Humin的反应模型对六碳糖降解动力学进行分析,揭示了六碳糖的类型对HMF和Humin生成机制的影响。此外,针对六碳糖生成的Humin的Van Krevelen图和FTIR谱图进行分析进一步发现,Humin是通过脱水聚合生成的呋喃环基聚合物,同时其结构特征与单糖类型紧密相关。%The conversion of mannose and galactose to 5-hydroxymethylfurfural(HMF)was investigated under aqueous conditions at a wide range of temperature(100~200℃)and time(10~240min)without catalyst. The results showed that higher temperature favored the decomposition of hexoses and increased the yield of HMF. At 200℃,the maximum yields of HMF for mannose and galactose were 26.82% and 22.86%,respectively,and their levulinic acid(LA)yields were at a low level below 3%. The lower yield of HMF from galactose because isomerization to tagatose is easier than that to fructose. A reaction model that hexose firstly decomposed to HMF and Humin,followed by the degradation of HMF to LA and Humin,was used to analyze the reaction kinetics. The model predicted the experiment results well. The obtained kinetic parameters revealed the varied mechanisms of HMF and Humin formation from different types of hexose. Finally,structural characterization of the Humins based on the Van Krevelen diagram and FTIR spectra showed that the Humins were furanic polymers formed by dehydration and condensation

  15. Does internal climate variability overwhelm climate change signals in streamflow? The upper Po and Rhone basin case studies.

    Science.gov (United States)

    Fatichi, S; Rimkus, S; Burlando, P; Bordoy, R

    2014-09-15

    Projections of climate change effects in streamflow are increasingly required to plan water management strategies. These projections are however largely uncertain due to the spread among climate model realizations, internal climate variability, and difficulties in transferring climate model results at the spatial and temporal scales required by catchment hydrology. A combination of a stochastic downscaling methodology and distributed hydrological modeling was used in the ACQWA project to provide projections of future streamflow (up to year 2050) for the upper Po and Rhone basins, respectively located in northern Italy and south-western Switzerland. Results suggest that internal (stochastic) climate variability is a fundamental source of uncertainty, typically comparable or larger than the projected climate change signal. Therefore, climate change effects in streamflow mean, frequency, and seasonality can be masked by natural climatic fluctuations in large parts of the analyzed regions. An exception to the overwhelming role of stochastic variability is represented by high elevation catchments fed by glaciers where streamflow is expected to be considerably reduced due to glacier retreat, with consequences appreciable in the main downstream rivers in August and September. Simulations also identify regions (west upper Rhone and Toce, Ticino river basins) where a strong precipitation increase in the February to April period projects streamflow beyond the range of natural climate variability during the melting season. This study emphasizes the importance of including internal climate variability in climate change analyses, especially when compared to the limited uncertainty that would be accounted for by few deterministic projections. The presented results could be useful in guiding more specific impact studies, although design or management decisions should be better based on reliability and vulnerability criteria as suggested by recent literature.

  16. A Spitzer IRS Study of Infrared Variability in Transitional and Pre-Transitional Disks around T Tauri Stars

    CERN Document Server

    Espaillat, C; D'Alessio, P; Sargent, B; Nagel, E; Calvet, N; Watson, Dan M; Muzerolle, J

    2010-01-01

    We present a Spitzer IRS study of variability in 14 T Tauri stars in the Taurus and Chamaeleon star-forming regions. The sample is composed of transitional and pre-transitional objects which contain holes and gaps in their disks. We detect variability between 5-38 microns in all but two of our objects on timescales of 2-3 years. Most of the variability observed can be classified as seesaw behavior, whereby the emission at shorter wavelengths varies inversely with the emission at longer wavelengths. For many of the objects we can reasonably reproduce the observed variability using irradiated disk models, particularly by changing the height of the inner disk wall by ~20%. When the inner wall is taller, the emission at the shorter wavelengths is higher since the inner wall dominates the emission at 2-8 microns. The taller inner wall casts a larger shadow on the outer disk wall, leading to less emission at wavelengths beyond 20 microns where the outer wall dominates. We discuss how the possible presence of planet...

  17. Children with New Onset Seizures: A Prospective Study of Parent Variables, Child Behavior Problems, and Seizure Occurrence

    Science.gov (United States)

    Austin, Joan K.; Haber, Linda C.; Dunn, David W.; Shore, Cheryl P.; Johnson, Cynthia S.; Perkins, Susan M.

    2015-01-01

    Objective Parent variables (stigma, mood, unmet needs for information and support, and worry) are associated with behavioral difficulties in children with seizures, however, it is not known how this relationship is influenced by additional seizures. This study followed children (ages 4 – 14 years) and their parents over a 24-month period (with data collected at baseline, 6, 12, and 24 months) and investigated the effect of an additional seizure on the relationship between parenting variables and child behavior difficulties. Methods The sample was parents of 196 children (104 girls and 92 boys) with a first seizure within the past 6 weeks. Child mean age at baseline was 8 years, 3 months (SD 3 years). Data were analyzed using t-tests, chi-square tests, and repeated measures analyses of covariance. Results Relationships between parent variables, additional seizures, and child behavior problems were consistent across time. Several associations between parent variables and child behavior problems were stronger in the additional seizure group than in the no additional seizures group. Conclusions Findings suggest that interventions that assist families to respond constructively to the reactions of others regarding their child's seizure condition and to address their needs for information and support could help families of children with continuing seizures to have an improved quality of life. PMID:26520879

  18. Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009

    CERN Document Server

    Ahnen, M L; Antonelli, L A; Antoranz, P; Babic, A; Banerjee, B; Bangale, P; de Almeida, U Barres; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Buson, S; Carosi, A; Chatterjee, A; Clavero, R; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Lotto, B; Wilhelmi, E de Oña; Di Pierro, F; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Glawion, D Eisenacher; Elsaesser, D; Fernández-Barral, A; Fidalgo, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giammaria, P; Godinović, N; Muñoz, A González; Gora, D; Guberman, D; Hadasch, D; Hahn, A; Hanabata, Y; Hayashida, M; Herrera, J; Hose, J; Hrupec, D; Hughes, G; Idec, W; Kodani, K; Konno, Y; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; Majumdar, P; Makariev, M; Mallot, K; Maneva, G; Manganaro, M; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Moretti, E; Nakajima, D; Neustroev, V; Niedzwiecki, A; Rosillo, M Nievas; Nilsson, K; Nishijima, K; Noda, K; Nogués, L; Orito, R; Overkemping, A; Paiano, S; Palacio, J; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Pedaletti, G; Perri, L; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Saito, T; Satalecka, K; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Stamerra, A; Steinbring, T; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Torres, D F; Toyama, T; Treves, A; Verguilov, V; Vovk, I; Ward, J E; Will, M; Wu, M H; Zanin, R; Blinov, D A; Chen, W P; Efimova, N V; Forné, E; Grishina, T S; Hovatta, T; Jordan, B; Kimeridze, G N; Kopatskaya, E N; Koptelova, E; Kurtanidze, O M; Kurtanidze, S O; Lähteenmaäki, A; Larionov, V M; Larionova, E G; Larionova, L V; Ligustri, R; Lin, H C; McBreen, B; Morozova, D A; Nikolashvili, M G; Raiteri, C M; Ros, J A; Sadun, A C; Sigua, L A; Tornikoski, M; Troitsky, I S; Villata, M

    2016-01-01

    We study the multi-band variability and correlations of the TeV blazar Mrk 421 on year time scales, which can bring additional insight on the processes responsible for its broadband emission. We observed Mrk 421 in the very high energy (VHE) gamma-ray range with the Cherenkov telescope MAGIC-I from March 2007 to June 2009 for a total of 96 hours of effective time after quality cuts. The VHE flux variability is quantified with several methods, including the Bayesian Block algorithm, which is applied to data from Cherenkov telescopes for the first time. The 2.3 year long MAGIC light curve is complemented with data from the Swift/BAT and RXTE/ASM satellites and the KVA, GASP-WEBT, OVRO, and Mets\\"ahovi telescopes from February 2007 to July 2009, allowing for an excellent characterisation of the multi-band variability and correlations over year time scales. Mrk 421 was found in different gamma-ray emission states during the 2.3 year long observation period. Flares and different levels of variability in the gamma-...

  19. Inter-individual variability of forces and modular muscle coordination in cycling: a study on untrained subjects.

    Science.gov (United States)

    De Marchis, Cristiano; Schmid, Maurizio; Bibbo, Daniele; Bernabucci, Ivan; Conforto, Silvia

    2013-12-01

    The aim of this study was to investigate the muscle coordination underlying pedaling in untrained subjects by using the muscle synergies paradigm, and to connect it with the inter-individual variability of EMG patterns and applied forces. Nine subjects performed a pedaling exercise on a cycle-simulator. Applied forces were recorded by means of instrumented pedals able to measure two force components. EMG signals were recorded from eight muscles of the dominant leg, and Nonnegative Matrix Factorization was applied to extract muscle synergy vectors W and time-varying activation coefficients H. Inter-individual variability was assessed for EMG patterns, force profiles, and H. Four modules were sufficient to reconstruct the muscle activation repertoire for all the subjects (variance accounted for >90% for each muscle). These modules were found to be highly similar between subjects in terms of W (mean r=.89), while most of the variability in force profiles and EMG patterns was reflected, in the muscle synergy structure, in the variability of H. These four modules have a functional interpretation when related to force distribution along the pedaling cycle, and the structure of W is shared with that present in human walking, suggesting the existence of a modular motor control in humans.

  20. Climate data, analysis and models for the study of natural variability and anthropogenic change

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Philip D. [Univ. of East Anglia, Norwich (United Kingdom)

    2014-07-31

    Gridded Temperature Under prior/current support, we completed and published (Jones et al., 2012) the fourth major update to our global land dataset of near-surface air temperatures, CRUTEM4. This is one of the most widely used records of the climate system, having been updated, maintained and further developed with DoE support since the 1980s. We have continued to update the CRUTEM4 (Jones et al., 2012) database that is combined with marine data to produce HadCRUT4 (Morice et al., 2012). The emphasis in our use of station temperature data is to access as many land series that have been homogenized by National Meteorological Services (NMSs, including NCDC/NOAA, Asheville, NC). Unlike the three US groups monitoring surface temperatures in a similar way, we do not infill areas that have no or missing data. We can only infill such regions in CRUTEM4 by accessing more station temperature series. During early 2014, we have begun the extensive task of updating as many of these series as possible using data provided by some NMSs and also through a number of research projects and programs around the world. All the station data used in CRUTEM4 have been available since 2009, but in Osborn and Jones (2014) we have made this more usable using a Google Earth interface (http://www.cru.uea.ac.uk/cru/data/crutem/ge/ ). We have recently completed the update of our infilled land multi-variable dataset (CRU TS 3.10, Harris et al., 2014). This additionally produces complete land fields (except for the Antarctic) for temperature, precipitation, diurnal temperature range, vapour pressure and sunshine/cloud. Using this dataset we have calculated sc-PDSI (self-calibrating Palmer Drought Severity Index) data and compared with other PDSI datasets (Trenberth et al., 2014). Also using CRU TS 3.10 and Reanalysis datasets, we showed no overall increase in global temperature variability despite changing regional patterns (Huntingford et al., 2013). Harris et al. (2014) is an update of an earlier

  1. Fermi-LAT Gamma-Ray Variability Study of Misaligned AGN

    Science.gov (United States)

    Grandi, P.; Torresi, E.; De Rosa, A.; Rainó, S.; Malaguti, G.

    2013-12-01

    We review the gamma-ray variability properties of AGN with a jet not directly pointing at the observer, i.e. Misaligned AGN. This class is mainly populated by nearby low power radio galaxies (i.e. FRIs). The high power radio sources (i.e. FRIIs) are indeed rare in the GeV sky. Our Fermi-LAT inspection of 4 years of data reveals different temporal behaviors, supporting the idea that beaming/jet structural differences could characterize the FRI-FRII jets. The case of 3C111 (FRII) and NGC6251 (FRI) are treated in detail. New insights into the location and dimension of the gamma-ray dissipation regions are provided for galaxies with different radio morphologies.

  2. Fermi-LAT Gamma-Ray Variability Study of Misaligned AGN

    Directory of Open Access Journals (Sweden)

    Grandi P.

    2013-12-01

    Full Text Available We review the gamma-ray variability properties of AGN with a jet not directly pointing at the observer, i.e. Misaligned AGN. This class is mainly populated by nearby low power radio galaxies (i.e. FRIs. The high power radio sources (i.e. FRIIs are indeed rare in the GeV sky. Our Fermi-LAT inspection of 4 years of data reveals different temporal behaviors, supporting the idea that beaming/jet structural differences could characterize the FRI-FRII jets. The case of 3C111 (FRII and NGC6251 (FRI are treated in detail. New insights into the location and dimension of the gamma-ray dissipation regions are provided for galaxies with different radio morphologies.

  3. Parametric Study on Important Variables of Aircraft Impact to Prestressed Concrete Containment Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sangshup; Hahm, Daegi; Choi, Inkil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    In this paper, to find the damage parameter, it is necessary to use many analysis cases and the time reduction. Thus, this paper uses a revised version of Riera's method. Using this method, the response has been found a Prestressed Concrete Containments Vessels (PCCVs) subject to impact loading, and the results of the velocity and mass of the important parameters have been analyzed. To find the response of the PCCVs subjected to aircraft impact load, it is made that a variable forcing functions depending on the velocity and fuel in the paper. The velocity variation affects more than fuel percentage, and we expect that the severe damage of the PCCVs with the same material properties is subject to aircraft impact load (more than 200m/s and 70%)

  4. Variable selection methods in PLS regression - a comparison study on metabolomics data

    DEFF Research Database (Denmark)

    Karaman, İbrahim; Hedemann, Mette Skou; Knudsen, Knud Erik Bach

    Partial least squares regression (PLSR) has been applied to various fields such as psychometrics, consumer science, econometrics and process control. Recently it has been applied to metabolomics based data sets (GC/LC-MS, NMR) and proven to be a very powerful in situations with many variables...... for the purpose of reducing over-fitting problems and providing useful interpretation tools. It has excellent possibilities for giving a graphical overview of sample and variation patterns. It can handle co-linearity in an efficient way and make it possible to use different highly correlated data sets in one...... Integrating Omics data. Statistical Applications in Genetics and Molecular Biology, 7:Article 35, 2008. 2. Martens H and Martens M. Modifed Jack-knife estimation of parameter uncertainty in bilinear modelling by partial least squares regression (PLSR). Food Quality and Preference, 11:5-16, 2000....

  5. Linguistic Explanation and Domain Specialization: a case study in bound variable anaphora

    Directory of Open Access Journals (Sweden)

    David eAdger

    2015-09-01

    Full Text Available The core question behind this Frontiers research topic is whether explaining linguistic phenomena requires appeal to properties of human cognition that are specialised to language. We argue here that investigating this issue requires taking linguistic research results seriously, and evaluating these for domain-specificity. We present a particular empirical phenomenon, bound variable interpretations of pronouns dependent on a quantifier phrase, and argue for a particular theory of this empirical domain that is couched at a level of theoretical depth which allows its principles to be evaluated for domain-specialisation. We argue that the relevant principles are specialised when they apply in the domain of language, even if analogues of them are plausibly at work elsewhere in cognition or the natural world more generally. So certain principles may be specialised to language, though not, ultimately, unique to it. Such specialisation is underpinned by ultimately biological factors, hence part of UG.

  6. [Heart rate variability study based on a novel RdR RR Intervals Scatter Plot].

    Science.gov (United States)

    Lu, Hongwei; Lu, Xiuyun; Wang, Chunfang; Hua, Youyuan; Tian, Jiajia; Liu, Shihai

    2014-08-01

    On the basis of Poincare scatter plot and first order difference scatter plot, a novel heart rate variability (HRV) analysis method based on scatter plots of RR intervals and first order difference of RR intervals (namely, RdR) was proposed. The abscissa of the RdR scatter plot, the x-axis, is RR intervals and the ordinate, y-axis, is the difference between successive RR intervals. The RdR scatter plot includes the information of RR intervals and the difference between successive RR intervals, which captures more HRV information. By RdR scatter plot analysis of some records of MIT-BIH arrhythmias database, we found that the scatter plot of uncoupled premature ventricular contraction (PVC), coupled ventricular bigeminy and ventricular trigeminy PVC had specific graphic characteristics. The RdR scatter plot method has higher detecting performance than the Poincare scatter plot method, and simpler and more intuitive than the first order difference method.

  7. The variability of processes involved in transgene dispersal - case studies from Brassica and related genera

    DEFF Research