WorldWideScience

Sample records for nonrandomly occurring clusters

  1. The non-random clustering of non-synonymous substitutions and its relationship to evolutionary rate

    Directory of Open Access Journals (Sweden)

    Stone Eric A

    2011-08-01

    Full Text Available Abstract Background Protein sequences are subject to a mosaic of constraint. Changes to functional domains and buried residues, for example, are more apt to disrupt protein structure and function than are changes to residues participating in loops or exposed to solvent. Regions of constraint on the tertiary structure of a protein often result in loose segmentation of its primary structure into stretches of slowly- and rapidly-evolving amino acids. This clustering can be exploited, and existing methods have done so by relying on local sequence conservation as a signature of selection to help identify functionally important regions within proteins. We invert this paradigm by leveraging the regional nature of protein structure and function to both illuminate and make use of genome-wide patterns of local sequence conservation. Results Our hypothesis is that the regional nature of structural and functional constraints will assert a positive autocorrelation on the evolutionary rates of neighboring sites, which, in a pairwise comparison of orthologous proteins, will manifest itself as the clustering of non-synonymous changes across the amino acid sequence. We introduce a dispersion ratio statistic to test this and related hypotheses. Using genome-wide interspecific comparisons of orthologous protein pairs, we reveal a strong log-linear relationship between the degree of clustering and the intensity of constraint. We further demonstrate how this relationship varies with the evolutionary distance between the species being compared. We provide some evidence that proteins with a history of positive selection deviate from genome-wide trends. Conclusions We find a significant association between the evolutionary rate of a protein and the degree to which non-synonymous changes cluster along its primary sequence. We show that clustering is a non-redundant predictor of evolutionary rate, and we speculate that conflicting signals of clustering and constraint may

  2. Nonrandom spatial clustering of spontaneous anterior fossa cerebrospinal fluid fistulas and predilection for the posterior cribriform plate.

    Science.gov (United States)

    Murray, Richard D; Friedlander, Rachel; Hanz, Samuel; Singh, Harminder; Anand, Vijay K; Schwartz, Theodore H

    2017-05-01

    OBJECTIVE The anterior skull base is a common site for the spontaneous development of meningoceles, encephaloceles, and meningoencephaloceles that can lead to cerebrospinal fluid (CSF) fistula formation, particularly in association with idiopathic intracranial hypertension. In some circumstances the lesions are difficult to localize. Whether all sites in the anterior skull base are equally prone to fistula formation or whether they are distributed randomly throughout the anterior skull base is unknown, although the anterior cribriform plate has been proposed as the most frequent location. The purpose of this study was to identify sites of predilection in order to provide assistance for clinicians in finding occult leaks and increase the understanding of the etiology of this pathology. METHODS The authors performed a retrospective review of a prospectively acquired surgical database of all endonasal endoscopic surgeries performed at Weill Cornell Medical College by the senior authors. Spontaneous CSF fistulas of the anterior skull base were identified. The anatomical sites of the defects were located on radiographic images and normalized to a theoretical 4 × 2 grid representing the anterior midline skull base. Data from the left and right skull base were combined to increase statistical power. This grid was then used to analyze the distribution of defects. Frequency analysis was performed by means of a chi-square test, with a subsequent Monte Carlo simulation to further strengthen the statistical support of the conclusions. RESULTS Nineteen cases of spontaneous CSF fistulas were identified. Frequency analysis using chi-square indicated a nonrandom distribution of sites (p = 0.035). Monte Carlo simulation supported this conclusion (p = 0.034). Seventy-four percent of cases occurred in the cribriform plate (p = 0.086). Moreover, 37% of all defects occurred in the posterior third of the cribriform plate. CONCLUSIONS Anterior skull base spontaneous CSF leaks are

  3. Vector integration is nonrandom and clustered and influences the fate of lymphopoiesis in SCID-X1 gene therapy.

    Science.gov (United States)

    Deichmann, Annette; Hacein-Bey-Abina, Salima; Schmidt, Manfred; Garrigue, Alexandrine; Brugman, Martijn H; Hu, Jingqiong; Glimm, Hanno; Gyapay, Gabor; Prum, Bernard; Fraser, Christopher C; Fischer, Nicolas; Schwarzwaelder, Kerstin; Siegler, Maria-Luise; de Ridder, Dick; Pike-Overzet, Karin; Howe, Steven J; Thrasher, Adrian J; Wagemaker, Gerard; Abel, Ulrich; Staal, Frank J T; Delabesse, Eric; Villeval, Jean-Luc; Aronow, Bruce; Hue, Christophe; Prinz, Claudia; Wissler, Manuela; Klanke, Chuck; Weissenbach, Jean; Alexander, Ian; Fischer, Alain; von Kalle, Christof; Cavazzana-Calvo, Marina

    2007-08-01

    Recent reports have challenged the notion that retroviruses and retroviral vectors integrate randomly into the host genome. These reports pointed to a strong bias toward integration in and near gene coding regions and, for gammaretroviral vectors, around transcription start sites. Here, we report the results obtained from a large-scale mapping of 572 retroviral integration sites (RISs) isolated from cells of 9 patients with X-linked SCID (SCID-X1) treated with a retrovirus-based gene therapy protocol. Our data showed that two-thirds of insertions occurred in or very near to genes, of which more than half were highly expressed in CD34(+) progenitor cells. Strikingly, one-fourth of all integrations were clustered as common integration sites (CISs). The highly significant incidence of CISs in circulating T cells and the nature of their locations indicate that insertion in many gene loci has an influence on cell engraftment, survival, and proliferation. Beyond the observed cases of insertional mutagenesis in 3 patients, these data help to elucidate the relationship between vector insertion and long-term in vivo selection of transduced cells in human patients with SCID-X1.

  4. Predictors of suicides occurring within suicide clusters in Australia, 2004-2008.

    Science.gov (United States)

    Derek Cheung, Yee Tak; Spittal, Matthew J; Williamson, Michelle Kate; Tung, Sui Jay; Pirkis, Jane

    2014-10-01

    A number of studies have investigated the presence of suicide clusters, but few have sought to identify risk and protective factors of a suicide occurring within a cluster. We aimed to identify socio-demographic and contextual characteristics of suicide clusters from national and regional analyses of suicide clusters. We searched the National Coroners Information System for all suicides in Australia from 2004 to 2008. Scan statistics were initially used to identify those deaths occurring within a spatial-temporal suicide cluster during the period. We then used logistic regression and generalized estimation equations to estimate the odds of each suicide occurring within a cluster differed by sex, age, marital status, employment status, Indigenous status, method of suicide and location. We identified 258 suicides out of 10,176 suicides during the period that we classified as being within a suicide cluster. When the deceased was Indigenous, living outside a capital city, or living in the northern part of Australia (in particular, Northern Territory, Queensland and Western Australia) then there was an increased likelihood of their death occurring within a suicide cluster. These findings suggest that suicide clustering might be linked with geographical and Indigenous factors, which supported sociological explanations of suicide clustering. This finding is significant for justifying resource allocation for tackling suicide clustering in particular areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The Nonrandom Brain: Efficiency, Economy, and Complex Dynamics

    Directory of Open Access Journals (Sweden)

    Olaf eSporns

    2011-02-01

    Full Text Available Modern anatomical tracing and imaging techniques are beginning to reveal the structural anatomy of neural circuits at small and large scales in unprecedented detail. When examined with analytic tools from graph theory and network science, neural connectivity exhibits highly nonrandom features, including high clustering and short path length, as well as modules and highly central hub nodes. These characteristic topological features of neural connections shape nonrandom dynamic interactions that occur during spontaneous activity or in response to external stimulation. Disturbances of connectivity and thus of neural dynamics are thought to underlie a number of disease states of the brain, and some evidence suggests that degraded functional performance of brain networks may be the outcome of a process of randomization affecting their nodes and edges. This article provides a survey of the nonrandom structure of neural connectivity, primarily at the large-scale of regions and pathways in the mammalian cerebral cortex. In addition, we will discuss how nonrandom connections can give rise to differentiated and complex patterns of dynamics and information flow. Finally, we will explore the idea that at least some disorders of the nervous system are associated with increased randomness of neural connections.

  6. Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters.

    Science.gov (United States)

    Breckwoldt, Michael O; Armoundas, Antonis A; Aon, Miguel A; Bendszus, Martin; O'Rourke, Brian; Schwarzländer, Markus; Dick, Tobias P; Kurz, Felix T

    2016-03-22

    Redox switches are important mediators in neoplastic, cardiovascular and neurological disorders. We recently identified spontaneous redox signals in neurons at the single mitochondrion level where transients of glutathione oxidation go along with shortening and re-elongation of the organelle. We now have developed advanced image and signal-processing methods to re-assess and extend previously obtained data. Here we analyze redox and pH signals of entire mitochondrial populations. In total, we quantified the effects of 628 redox and pH events in 1797 mitochondria from intercostal axons and neuromuscular synapses using optical sensors (mito-Grx1-roGFP2; mito-SypHer). We show that neuronal mitochondria can undergo multiple redox cycles exhibiting markedly different signal characteristics compared to single redox events. Redox and pH events occur more often in mitochondrial clusters (medium cluster size: 34.1 ± 4.8 μm(2)). Local clusters possess higher mitochondrial densities than the rest of the axon, suggesting morphological and functional inter-mitochondrial coupling. We find that cluster formation is redox sensitive and can be blocked by the antioxidant MitoQ. In a nerve crush paradigm, mitochondrial clusters form sequentially adjacent to the lesion site and oxidation spreads between mitochondria. Our methodology combines optical bioenergetics and advanced signal processing and allows quantitative assessment of entire mitochondrial populations.

  7. Nocturnal hypoxia in ALS is related to cognitive dysfunction and can occur as clusters of desaturations.

    Directory of Open Access Journals (Sweden)

    Su-Yeon Park

    Full Text Available BACKGROUND: Amyotrophic lateral sclerosis (ALS is a neurodegenerative disease that leads to progressive weakness of the respiratory and limb muscles. Consequently, most patients with ALS exhibit progressive hypoventilation, which worsens during sleep. The aim of this study was to evaluate the relationship between nocturnal hypoxia and cognitive dysfunction and to assess the pattern of nocturnal hypoxia in patients with ALS. METHOD: Twenty-five patients with definite or probable ALS underwent neuropsychologic testing, nocturnal pulse oximetry, and capnography. Patients were grouped according to the presence of nocturnal hypoxia (SpO2<95% for ≥10% of the night and their clinical characteristics and cognitive function were compared. RESULTS: Compared to patients without nocturnal hypoxia, those with nocturnal hypoxia (n = 10, 40% had poor memory retention (p = 0.039 and retrieval efficiency (p = 0.045. A cluster-of-desaturation pattern was identified in 7 patients (70% in the Hypoxia Group. CONCLUSIONS: These results suggest that nocturnal hypoxia can be related to cognitive dysfunction in ALS. In addition, a considerable number of patients with ALS may be exposed to repeated episodes of deoxygenation-reoxygenation (a cluster-of-desaturation pattern during sleep, which could be associated with the generation of reactive oxygen species. Further studies are required to define the exact causal relationships between these phenomena, the exact manifestations of nocturnal cluster-of-desaturation patterns, and the effect of clusters of desaturation on ALS progression.

  8. Effectiveness of the “What’s Up!” Intervention to Reduce Stigma and Psychometric Properties of the Youth Program Questionnaire (YPQ: Results from a Cluster Non-randomized Controlled Trial Conducted in Catalan High Schools

    Directory of Open Access Journals (Sweden)

    Laura Andrés-Rodríguez

    2017-09-01

    Full Text Available Mental disorders are highly prevalent in the general population, and people who experience them are frequently stigmatized. Stigma has a very negative impact on social, academic/professional, and personal life. Considering the high rates of mental disorders among children and adolescents (13.4% and how critical this age is in the formation of nuclear beliefs, many campaigns to combat stigma have been developed in the last decade, with mixed results. The OBERTAMENT initiative has produced various anti-stigma campaigns in Catalonia (Spain. In the present study, the main objective was to report on the effectiveness of the OBERTAMENT “What’s up!” intervention, a curricular intervention including education and social contact conducted by the teachers in the classroom with teenagers aged between 14 and 18. Prior to this, we examined the psychometric properties of the Youth Program Questionnaire (YPQ, our main outcome measure, in terms of dimensionality, reliability, and validity. A cluster non-randomized controlled trial was conducted to assess this intervention, which was tested in nine high schools situated in the Barcelona region. A convenience sample of 261 students formed the intervention group and 132 the control group (52% women, mean age = 14, SD = 0.47. The assignment to study conditions was conducted by Departament d’Ensenyament (Department of Education, Generalitat de Catalunya (Catalan Government. Participants were evaluated at baseline, post-intervention, and 9-month follow-up. The main outcome measure of this study was the YPQ. The Reported and Intended Behavior Scale (RIBS was used as secondary outcome measure. The statistical analysis indicated that the YPQ possesses a two-factor structure (stereotypical attitudes and intended behavior and sound psychometric properties. The multilevel mixed-effects models revealed statistically significant interactions for both study measures and post hoc intragroup analyses revealed a

  9. Simulation of the K-function in the analysis of spatial clustering for non-randomly distributed locations-Exemplified by bovine virus diarrhoea virus (BVDV) infection in Denmark

    DEFF Research Database (Denmark)

    Ersbøll, Annette Kjær; Ersbøll, Bjarne Kjær

    2009-01-01

    The K-function is often used to detect spatial clustering in spatial point processes, e.g. clustering of infected herds. Clustering is identified by testing the observed K-function for complete spatial randomness modelled, e.g. by a homogeneous Poisson process. The approach provides information a...... of the herd locations in general. The approach also overcomes edge effects and problems with complex shapes of the study region. An application to bovine virus diarrhoea virus (BVDV) infection in Denmark is described....

  10. Nonredox thiolation in tRNA occurring via sulfur activation by a [4Fe-4S] cluster.

    Science.gov (United States)

    Arragain, Simon; Bimai, Ornella; Legrand, Pierre; Caillat, Sylvain; Ravanat, Jean-Luc; Touati, Nadia; Binet, Laurent; Atta, Mohamed; Fontecave, Marc; Golinelli-Pimpaneau, Béatrice

    2017-07-11

    Sulfur is present in several nucleosides within tRNAs. In particular, thiolation of the universally conserved methyl-uridine at position 54 stabilizes tRNAs from thermophilic bacteria and hyperthermophilic archaea and is required for growth at high temperature. The simple nonredox substitution of the C2-uridine carbonyl oxygen by sulfur is catalyzed by tRNA thiouridine synthetases called TtuA. Spectroscopic, enzymatic, and structural studies indicate that TtuA carries a catalytically essential [4Fe-4S] cluster and requires ATP for activity. A series of crystal structures shows that (i) the cluster is ligated by only three cysteines that are fully conserved, allowing the fourth unique iron to bind a small ligand, such as exogenous sulfide, and (ii) the ATP binding site, localized thanks to a protein-bound AMP molecule, a reaction product, is adjacent to the cluster. A mechanism for tRNA sulfuration is suggested, in which the unique iron of the catalytic cluster serves to bind exogenous sulfide, thus acting as a sulfur carrier.

  11. Testing failure surface prediction methods and deposit reconstruction for the landslides cluster occurring during Talas Typhoon (Japan)

    Science.gov (United States)

    Jaboyedoff, Michel; Chigira, Masahiro; Arai, Noriyuki; Derron, Marc-Henri; Rudaz, Benjamin; Tsou, Ching-Ying

    2016-04-01

    Talas Typhoon hit Japan from 2 to 5 September 2011. It induced more than 70 deep-seated landslides in Kii peninsula. The hi-resolution topography of these landslides have been acquired by aerial 1 m LiDAR digital elevation models (DEM) before (pre-DEM) and after (post-DEM) the events (data from Nara prefectural Government and the Kinki Regional development Bureau of Ministry of Land, Infrastructure, Transportation, and Tourism). This extraordinary opportunity allows us to test methods to construct failure surface geometries, buried valley topographies and/or to rebuild deposits surfaces. We tested the sloping base local level method (SLBL) on 5 deep seated landslides which occurred during Typhoon Talas (Akatani, Kitamata, Nagatono, Shimizu and Akatani-East; see Chigira et al., 2013). The SLBL corresponds to a quadratic surface with a constant second derivative in all x-y directions. This curvature can be based on the knowledge of the length of the landslide and its maximum thickness. We used mainly hillshade DEM, slope maps and Coltop schemes to define the limits of landslides and to interpret their structures. Different attempts were performed to reconstruct the failure surface and deposits depending on a priori knowledge. Basically the morphological features extracted from the pre-DEM were used to delineate the limits of the landslides. The curvature of the failure surface was obtained by "expert" interpretations. The failure surfaces obtained using SLBL are in good agreement with the failure surface observed on the post-DEM. The results are improved when (1) they are adjusted to obtain similar estimate of the volume deduced by Chigira et al. (2013), and when (2) the contours of the landslides used comes from an interpretation of both post and pre-DEM. In order to obtain the expansion coefficient some of these landslide, the missing volume of the deposits (by river erosion) were calculated using inverse SLBL. The coefficient of expansion ranges from 13% to 30

  12. Downregulation of anti-oncomirs miR-143/145 cluster occurs before APC gene aberration in the development of colorectal tumors.

    Science.gov (United States)

    Kamatani, Akemi; Nakagawa, Yoshihito; Akao, Yukihiro; Maruyama, Naoko; Nagasaka, Mitsuo; Shibata, Tomoyuki; Tahara, Tomomitsu; Hirata, Ichiro

    2013-09-01

    Accumulating data indicate that some microRNAs (miRNAs or miRs) can function as tumor suppressors or oncogenes and as such are important in cancer development. We previously reported that miR-143 and -145 are frequently downregulated in colon adenomas and cancers, acting as tumor suppressors. In this present study, we investigated the relationship between the downregulation of the miR-143/145 cluster and genetic aberrations of adenomatous polyposis coli (APC), which are early genetic events in the development of colorectal tumors. The expression levels of both miRs were determined by performing real-time PCR on tissue samples of familial adenomatous polyposis (FAP), colorectal adenoma, colorectal cancer, and paired non-tumorous tissues. Also, the expression of C- or N-terminus of the APC protein and that of the p53 protein in these tissues were examined immunohistochemically. Our data clearly indicated that the decreased expression of miR-143 and -145 frequently occurred before APC gene aberrations. The downregulation of miR-143 and -145 is thus an important genetic event for the initiation step in colorectal tumor development.

  13. Frugivores bias seed-adult tree associations through nonrandom seed dispersal: a phylogenetic approach.

    Science.gov (United States)

    Razafindratsima, Onja H; Dunham, Amy E

    2016-08-01

    Frugivores are the main seed dispersers in many ecosystems, such that behaviorally driven, nonrandom patterns of seed dispersal are a common process; but patterns are poorly understood. Characterizing these patterns may be essential for understanding spatial organization of fruiting trees and drivers of seed-dispersal limitation in biodiverse forests. To address this, we studied resulting spatial associations between dispersed seeds and adult tree neighbors in a diverse rainforest in Madagascar, using a temporal and phylogenetic approach. Data show that by using fruiting trees as seed-dispersal foci, frugivores bias seed dispersal under conspecific adults and under heterospecific trees that share dispersers and fruiting time with the dispersed species. Frugivore-mediated seed dispersal also resulted in nonrandom phylogenetic associations of dispersed seeds with their nearest adult neighbors, in nine out of the 16 months of our study. However, these nonrandom phylogenetic associations fluctuated unpredictably over time, ranging from clustered to overdispersed. The spatial and phylogenetic template of seed dispersal did not translate to similar patterns of association in adult tree neighborhoods, suggesting the importance of post-dispersal processes in structuring plant communities. Results suggest that frugivore-mediated seed dispersal is important for structuring early stages of plant-plant associations, setting the template for post-dispersal processes that influence ultimate patterns of plant recruitment. Importantly, if biased patterns of dispersal are common in other systems, frugivores may promote tree coexistence in biodiverse forests by limiting the frequency and diversity of heterospecific interactions of seeds they disperse.

  14. Functional specialization in nucleotide sugar transporters occurred through differentiation of the gene cluster EamA (DUF6 before the radiation of Viridiplantae

    Directory of Open Access Journals (Sweden)

    Fredriksson Robert

    2011-05-01

    Full Text Available Abstract Background The drug/metabolite transporter superfamily comprises a diversity of protein domain families with multiple functions including transport of nucleotide sugars. Drug/metabolite transporter domains are contained in both solute carrier families 30, 35 and 39 proteins as well as in acyl-malonyl condensing enzyme proteins. In this paper, we present an evolutionary analysis of nucleotide sugar transporters in relation to the entire superfamily of drug/metabolite transporters that considers crucial intra-protein duplication events that have shaped the transporters. We use a method that combines the strengths of hidden Markov models and maximum likelihood to find relationships between drug/metabolite transporter families, and branches within families. Results We present evidence that the triose-phosphate transporters, domain unknown function 914, uracil-diphosphate glucose-N-acetylglucosamine, and nucleotide sugar transporter families have evolved from a domain duplication event before the radiation of Viridiplantae in the EamA family (previously called domain unknown function 6. We identify previously unknown branches in the solute carrier 30, 35 and 39 protein families that emerged simultaneously as key physiological developments after the radiation of Viridiplantae, including the "35C/E" branch of EamA, which formed in the lineage of T. adhaerens (Animalia. We identify a second cluster of DMTs, called the domain unknown function 1632 cluster, which has non-cytosolic N- and C-termini, and thus appears to have been formed from a different domain duplication event. We identify a previously uncharacterized motif, G-X(6-G, which is overrepresented in the fifth transmembrane helix of C-terminal domains. We present evidence that the family called fatty acid elongases are homologous to transporters, not enzymes as had previously been thought. Conclusions The nucleotide sugar transporters families were formed through differentiation of the

  15. Anderson transition in low-dimensional disordered systems driven by long-range nonrandom hopping.

    Science.gov (United States)

    Rodríguez, A; Malyshev, V A; Sierra, G; Martín-Delgado, M A; Rodríguez-Laguna, J; Domínguez-Adame, F

    2003-01-17

    The single-parameter scaling hypothesis predicts the absence of delocalized states for noninteracting quasiparticles in low-dimensional disordered systems. We show analytically, using a supersymmetric method combined with a renormalization group analysis, as well as numerically that extended states may occur in the one- and two-dimensional Anderson model with a nonrandom hopping falling off as some power of the distance between sites. The different size scaling of the bare level spacing and the renormalized magnitude of the disorder seen by the quasiparticles finally results in the delocalization of states at one of the band edges of the quasiparticle energy spectrum.

  16. Nonrandom Assignment in ANCOVA: The Alternate Ranks Design

    Science.gov (United States)

    Dalton, Starrett; Overall, John E.

    1977-01-01

    A specific form of nonrandom assignment to treatment groups, the "alternate ranks" design, was investigated. This design eliminates the possibility of a correlation between the covariate and the treatment, and rules out experimenter bias in assignment of subjects to groups. (Editor)

  17. Estimates of External Validity Bias When Impact Evaluations Select Sites Nonrandomly

    Science.gov (United States)

    Bell, Stephen H.; Olsen, Robert B.; Orr, Larry L.; Stuart, Elizabeth A.

    2016-01-01

    Evaluations of educational programs or interventions are typically conducted in nonrandomly selected samples of schools or districts. Recent research has shown that nonrandom site selection can yield biased impact estimates. To estimate the external validity bias from nonrandom site selection, we combine lists of school districts that were…

  18. Nonrandom involvement of chromosomal segments in human hematologic malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, J. D.

    1977-01-01

    The consistent occurrence of nonrandom chromosome changes in human malignancies suggests that they are not trivial epiphenomena. Whereas we do not understand their significance at present, one possible role which they may fulfill is to provide the chromosomally aberrant cells with a proliferative advantage as the result of alteration of the number and/or location of genes related to nucleic acid biosynthesis. It would be expected that the proliferative advantage provided by various chromosome aberrations differs in patients with different genetic constitutions.

  19. Calculating osmotic pressure according to nonelectrolyte Wilson nonrandom factor model.

    Science.gov (United States)

    Li, Hui; Zhan, Tingting; Zhan, Xiancheng; Wang, Xiaolan; Tan, Xiaoying; Guo, Yiping; Li, Chengrong

    2014-08-01

    Abstract The osmotic pressure of NaCl solutions was determined by the air humidity in equilibrium (AHE) method. The relationship between the osmotic pressure and the concentration was explored theoretically, and the osmotic pressure was calculated according to the nonelectrolyte Wilson nonrandom factor (N-Wilson-NRF) model from the concentration. The results indicate that the calculated osmotic pressure is comparable to the measured one.

  20. Nonrandom seedling establishment corresponds with distance-dependent decline in mycorrhizal abundance in two terrestrial orchids.

    Science.gov (United States)

    Waud, Michael; Wiegand, Thorsten; Brys, Rein; Lievens, Bart; Jacquemyn, Hans

    2016-07-01

    In plant species that critically rely on mycorrhizal symbionts for germination and seedling establishment, distance-dependent decline of mycorrhizal fungi in the soil can be hypothesized to lead to significant spatial clustering as a result of nonrandom spatial patterns of seedling establishment. To test this hypothesis, we investigated the abundance and distribution of mycorrhizal fungi in the soil and how they relate to spatial patterns of adults and seedling recruitment in two related orchid species. We combined assessments of spatial variation in fungal abundance using quantitative PCR (qPCR) with spatial point pattern analyses based on long-term demographic data and cluster point process models. qPCR analyses showed that fungal abundance declined rapidly with distance from the adult host plants. Spatial point pattern analyses showed that successful recruitment in both species was clustered significantly around adult plants and that the decline in the neighborhood density of recruits around adults coincided with the decline of fungal abundance around adult plants. Overall, these results indicate that the distribution and abundance of fungal associates in the soil may have a strong impact on the aboveground distribution of its partner.

  1. Microstructural descriptors and cellular automata simulation of the effects of non-random nuclei location on recrystallization in two dimensions

    Directory of Open Access Journals (Sweden)

    Paulo Rangel Rios

    2006-06-01

    Full Text Available The effect of non-random nuclei location and the efficiency of microstructural descriptors in assessing such a situation are studied. Cellular automata simulation of recrystallization in two dimensions is carried out to simulate microstrutural evolution for nuclei distribution ranging from a periodic arrangement to clusters of nuclei. The simulation results are compared in detail with microstrutural descriptors normally used to follow transformation evolution. It is shown that the contiguity is particularly relevant to detect microstructural deviations from randomness. This work focuses on recrystallization but its results are applicable to any nucleation and growth transformation.

  2. Non-random biodiversity loss underlies predictable increases in viral disease prevalence.

    Science.gov (United States)

    Lacroix, Christelle; Jolles, Anna; Seabloom, Eric W; Power, Alison G; Mitchell, Charles E; Borer, Elizabeth T

    2014-03-06

    Disease dilution (reduced disease prevalence with increasing biodiversity) has been described for many different pathogens. Although the mechanisms causing this phenomenon remain unclear, the disassembly of communities to predictable subsets of species, which can be caused by changing climate, land use or invasive species, underlies one important hypothesis. In this case, infection prevalence could reflect the competence of the remaining hosts. To test this hypothesis, we measured local host species abundance and prevalence of four generalist aphid-vectored pathogens (barley and cereal yellow dwarf viruses) in a ubiquitous annual grass host at 10 sites spanning 2000 km along the North American West Coast. In laboratory and field trials, we measured viral infection as well as aphid fecundity and feeding preference on several host species. Virus prevalence increased as local host richness declined. Community disassembly was non-random: ubiquitous hosts dominating species-poor assemblages were among the most competent for vector production and virus transmission. This suggests that non-random biodiversity loss led to increased virus prevalence. Because diversity loss is occurring globally in response to anthropogenic changes, such work can inform medical, agricultural and veterinary disease research by providing insights into the dynamics of pathogens nested within a complex web of environmental forces.

  3. Cluster-cluster clustering

    Science.gov (United States)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C. S.

    1985-01-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales.

  4. Cluster-cluster clustering

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C.S.

    1985-08-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales. 30 references.

  5. Next generation sequencing and FISH reveal uneven and nonrandom microsatellite distribution in two grasshopper genomes.

    Science.gov (United States)

    Ruiz-Ruano, Francisco J; Cuadrado, Ángeles; Montiel, Eugenia E; Camacho, Juan Pedro M; López-León, María Dolores

    2015-06-01

    Simple sequence repeats (SSRs), also known as microsatellites, are one of the prominent DNA sequences shaping the repeated fraction of eukaryotic genomes. In spite of their profuse use as molecular markers for a variety of genetic and evolutionary studies, their genomic location, distribution, and function are not yet well understood. Here we report the first thorough joint analysis of microsatellite motifs at both genomic and chromosomal levels in animal species, by a combination of 454 sequencing and fluorescent in situ hybridization (FISH) techniques performed on two grasshopper species. The in silico analysis of the 454 reads suggested that microsatellite expansion is not driving size increase of these genomes, as SSR abundance was higher in the species showing the smallest genome. However, the two species showed the same uneven and nonrandom location of SSRs, with clear predominance of dinucleotide motifs and association with several types of repetitive elements, mostly histone gene spacers, ribosomal DNA intergenic spacers (IGS), and transposable elements (TEs). The FISH analysis showed a dispersed chromosome distribution of microsatellite motifs in euchromatic regions, in coincidence with chromosome location patterns previously observed for many mobile elements in these species. However, some SSR motifs were clustered, especially those located in the histone gene cluster.

  6. Inbreeding avoidance through non-random mating in sticklebacks.

    Science.gov (United States)

    Frommen, Joachim G; Bakker, Theo C M

    2006-06-22

    Negative effects of inbreeding are well documented in a wide range of animal taxa. Hatching success and survival of inbred offspring is reduced in many species and inbred progeny are often less attractive to potential mates. Thus, individuals should avoid mating with close kin. However, experimental evidence for inbreeding avoidance through non-random mating in vertebrates is scarce. Here, we show that gravid female three-spined sticklebacks (Gasterosteus aculeatus) when given the choice between a courting familiar brother and a courting unfamiliar non-sib prefer to mate with the non-sib and thus avoid the disadvantages of incest. We controlled for differences in males' body size and red intensity of nuptial coloration. Thus, females adjust their courting behaviour to the risk of inbreeding.

  7. Evidence for Non-Random Hydrophobicity Structures in Protein Chains

    CERN Document Server

    Irbäck, A; Potthast, F; Irb\\"ack, Anders; Peterson, Carsten; Potthast, Frank

    1996-01-01

    The question of whether proteins originate from random sequences of amino acids is addressed. A statistical analysis is performed in terms of blocked and random walk values formed by binary hydrophobic assignments of the amino acids along the protein chains. Theoretical expectations of these variables from random distributions of hydrophobicities are compared with those obtained from functional proteins. The results, which are based upon proteins in the SWISS-PROT data base, convincingly show that the amino acid sequences in proteins differ from what is expected from random sequences in a statistical significant way. By performing Fourier transforms on the random walks one obtains additional evidence for non-randomness of the distributions. We have also analyzed results from a synthetic model containing only two amino-acid types, hydrophobic and hydrophilic. With reasonable criteria on good folding properties in terms of thermodynamical and kinetic behavior, sequences that fold well are isolated. Performing t...

  8. Causal inference methods to study nonrandomized, preexisting development interventions

    Science.gov (United States)

    Arnold, Benjamin F.; Khush, Ranjiv S.; Ramaswamy, Padmavathi; London, Alicia G.; Rajkumar, Paramasivan; Ramaprabha, Prabhakar; Durairaj, Natesan; Hubbard, Alan E.; Balakrishnan, Kalpana; Colford, John M.

    2010-01-01

    Empirical measurement of interventions to address significant global health and development problems is necessary to ensure that resources are applied appropriately. Such intervention programs are often deployed at the group or community level. The gold standard design to measure the effectiveness of community-level interventions is the community-randomized trial, but the conditions of these trials often make it difficult to assess their external validity and sustainability. The sheer number of community interventions, relative to randomized studies, speaks to a need for rigorous observational methods to measure their impact. In this article, we use the potential outcomes model for causal inference to motivate a matched cohort design to study the impact and sustainability of nonrandomized, preexisting interventions. We illustrate the method using a sanitation mobilization, water supply, and hygiene intervention in rural India. In a matched sample of 25 villages, we enrolled 1,284 children <5 y old and measured outcomes over 12 mo. Although we found a 33 percentage point difference in new toilet construction [95% confidence interval (CI) = 28%, 39%], we found no impacts on height-for-age Z scores (adjusted difference = 0.01, 95% CI = −0.15, 0.19) or diarrhea (adjusted longitudinal prevalence difference = 0.003, 95% CI = −0.001, 0.008) among children <5 y old. This study demonstrates that matched cohort designs can estimate impacts from nonrandomized, preexisting interventions that are used widely in development efforts. Interpreting the impacts as causal, however, requires stronger assumptions than prospective, randomized studies. PMID:21149699

  9. 42 CFR 421.505 - Termination and extension of non-random prepayment complex medical review.

    Science.gov (United States)

    2010-10-01

    ... a provider or supplier must be on non-random prepayment complex medical review. There is no minimum... section, a contractor must terminate a provider or supplier from non-random prepayment complex medical... complex medical review if a provider or supplier stops billing the code under review, shifts billing...

  10. Medicare Program; termination of non-random prepayment complex medical review. Final rule.

    Science.gov (United States)

    2008-09-26

    This final rule implements requirements regarding the termination of non-random prepayment complex medical review as required under the Medicare Prescription Drug, Improvement and Modernization Act of 2003. This final rule sets forth the criteria CMS contractors will use for terminating a provider or supplier from non-random prepayment complex medical review.

  11. Offender and offense characteristics of a nonrandom sample of adolescent mass murderers.

    Science.gov (United States)

    Meloy, J R; Hempel, A G; Mohandie, K; Shiva, A A; Gray, B T

    2001-06-01

    The authors conducted a descriptive, archival study of adolescent (mass murderers-subjects who intentionally killed three or more victims in one event-to identify demographic, clinical, and forensic characteristics. A nonrandom sample of convenience of adolescent mass murderers was utilized. Thirty-four subjects, acting alone or in pairs, committed 27 mass murders between 1958 and 1999. The sample consisted of males with a median age of 17. A majority were described as "loners" and abused alcohol or drugs; almost half were bullied by others, preoccupied with violent fantasy, and violent by history. Although 23% had a documented psychiatric history, only 6% were judged to have been psychotic at the time of the mass murder. Depressive symptoms and historical antisocial behaviors were predominant. There was a precipitating event in most cases--usually a perceived failure in love or school--and most subjects made threatening statements regarding the mass murder to third parties. The majority of the sample clustered into three types: the family annihilator, the classroom avenger, and the criminal opportunist. The adolescent mass murderer is often predatorily rather than affectively violent and typically does not show any sudden or highly emotional warning signs. Although the act of mass murder is virtually impossible to predict because of its extremely low frequency, certain clinical and forensic findings can alert the clinician to the need for further, intensified primary care, including family, school, community, law enforcement, and mental health intervention.

  12. Cluster Lenses

    CERN Document Server

    Kneib, Jean-Paul; 10.1007/s00159-011-0047-3

    2012-01-01

    Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining...

  13. Did Evolution Select a Nonrandom "Alphabet" of Amino Acids?

    Science.gov (United States)

    Philip, Gayle K.; Freeland, Stephen J.

    2011-04-01

    The last universal common ancestor of contemporary biology (LUCA) used a precise set of 20 amino acids as a standard alphabet with which to build genetically encoded protein polymers. Considerable evidence indicates that some of these amino acids were present through nonbiological syntheses prior to the origin of life, while the rest evolved as inventions of early metabolism. However, the same evidence indicates that many alternatives were also available, which highlights the question: what factors led biological evolution on our planet to define its standard alphabet? One possibility is that natural selection favored a set of amino acids that exhibits clear, nonrandom properties - a set of especially useful building blocks. However, previous analysis that tested whether the standard alphabet comprises amino acids with unusually high variance in size, charge, and hydrophobicity (properties that govern what protein structures and functions can be constructed) failed to clearly distinguish evolution's choice from a sample of randomly chosen alternatives. Here, we demonstrate unambiguous support for a refined hypothesis: that an optimal set of amino acids would spread evenly across a broad range of values for each fundamental property. Specifically, we show that the standard set of 20 amino acids represents the possible spectra of size, charge, and hydrophobicity more broadly and more evenly than can be explained by chance alone.

  14. Nonrandomized studies are not always found even when selection criteria for health systems intervention reviews include them: a methodological study.

    Science.gov (United States)

    Glenton, Claire; Lewin, Simon; Mayhew, Alain; Scheel, Inger; Odgaard-Jensen, Jan

    2013-04-01

    Systematic reviews within the Cochrane Effective Practice and Organisation of Care Group (EPOC) can include both randomized and nonrandomized study designs. We explored how many EPOC reviews consider and identify nonrandomized studies, and whether the proportion of nonrandomized studies identified is linked to the review topic. We recorded the study designs considered in 65 EPOC reviews. For reviews that considered nonrandomized studies, we calculated the proportion of identified studies that were nonrandomized and explored whether there were differences in the proportion of nonrandomized studies according to the review topic. Fifty-one (78.5%) reviews considered nonrandomized studies. Forty-six of these reviews found nonrandomized studies, but the proportion varied a great deal (median, 33%; interquartile range, 25--50%). Reviews of health care delivery interventions had lower proportions of nonrandomized studies than those of financial and governance interventions. Most EPOC reviews consider nonrandomized studies, but the degree to which they find them varies. As nonrandomized studies are believed to be at higher risk of bias and their inclusion entails a considerable effort, review authors should consider whether the benefits justify the inclusion of these designs. Research should explore whether it is more useful to consider nonrandomized studies in reviews of some intervention types than others. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. The Effect of Nonrandom Distribution of Molecules on the Equation of State for Gases

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Haeyoung [DukSung Women' s Univ., Seoul (Korea, Republic of)

    2013-10-15

    Using the free volume of van der Waals equation, Carnahan-Starling equation for hard spheres, Wilson equation for nonrandom mixing of solution, NRTL equation and our equation, several new equations of states for pure gases are derived. Using these equations, compressibility factors for pure gases are calculated and compared with Nelson-Obert generalized compressibility factor charts. The equation of states using the concept of molecular nonrandom distribution gave better results than those of molecular random distribution. This shows that the molecular nonrandom distribution makes considerable effect on the equation of states.

  16. Incomplete categorical data design non-randomized response techniques for sensitive questions in surveys

    CERN Document Server

    Tian, Guo-Liang

    2013-01-01

    Respondents to survey questions involving sensitive information, such as sexual behavior, illegal drug usage, tax evasion, and income, may refuse to answer the questions or provide untruthful answers to protect their privacy. This creates a challenge in drawing valid inferences from potentially inaccurate data. Addressing this difficulty, non-randomized response approaches enable sample survey practitioners and applied statisticians to protect the privacy of respondents and properly analyze the gathered data.Incomplete Categorical Data Design: Non-Randomized Response Techniqu

  17. Effect of non-random dispersal strategies on spatial coexistence mechanisms.

    Science.gov (United States)

    Amarasekare, Priyanga

    2010-01-01

    1. Random dispersal leads to spatial coexistence via two mechanisms (emigration-mediated and source-sink), both of which involve the movement of organisms from areas of higher to lower fitness. What is not known is whether such coexistence would occur if organisms dispersed non-randomly, using cues such as density and habitat quality to gauge fitness differences between habitats. Here, I conduct a comparative analysis of random and non-random dispersal strategies in a foodweb with a basal resource, top predator, and two intermediate consumers that exhibit a trade-off between competitive ability and predator susceptibility. 2. I find a striking contrast between density- and habitat-dependent dispersal in their effects on spatial coexistence. Dispersal in response to competitor and predator density facilitates coexistence while dispersal in response to habitat quality (resource productivity and predator pressure) inhibits it. Moreover, density-dependent dispersal changes species' distribution patterns from interspecific segregation to interspecific aggregation, while habitat-dependent dispersal preserves the interspecific segregation observed in the absence of dispersal. Under density-dependent dispersal, widespread spatial coexistence results in an overall decline in the abundance of the inferior competitor that is less susceptible to predation and an overall increase in the abundance of the superior competitor that is more susceptible to predation. Under habitat-dependent dispersal, restricted spatial coexistence results in species' abundances being essentially unchanged from those observed in the absence of dispersal. 3. A key outcome is that when the superior competitor moves in the direction of increasing fitness but the inferior competitor does not, spatial coexistence is possible in both resource-poor and resource-rich habitats. However, when the inferior competitor moves in the direction of increasing fitness but the superior competitor does not, spatial

  18. Synaptic signal streams generated by ex vivo neuronal networks contain non-random, complex patterns.

    Science.gov (United States)

    Lee, Sangmook; Zemianek, Jill M; Shultz, Abraham; Vo, Anh; Maron, Ben Y; Therrien, Mikaela; Courtright, Christina; Guaraldi, Mary; Yanco, Holly A; Shea, Thomas B

    2014-11-01

    Cultured embryonic neurons develop functional networks that transmit synaptic signals over multiple sequentially connected neurons as revealed by multi-electrode arrays (MEAs) embedded within the culture dish. Signal streams of ex vivo networks contain spikes and bursts of varying amplitude and duration. Despite the random interactions inherent in dissociated cultures, neurons are capable of establishing functional ex vivo networks that transmit signals among synaptically connected neurons, undergo developmental maturation, and respond to exogenous stimulation by alterations in signal patterns. These characteristics indicate that a considerable degree of organization is an inherent property of neurons. We demonstrate herein that (1) certain signal types occur more frequently than others, (2) the predominant signal types change during and following maturation, (3) signal predominance is dependent upon inhibitory activity, and (4) certain signals preferentially follow others in a non-reciprocal manner. These findings indicate that the elaboration of complex signal streams comprised of a non-random distribution of signal patterns is an emergent property of ex vivo neuronal networks.

  19. Reducing bias in survival under non-random temporary emigration

    Science.gov (United States)

    Peñaloza, Claudia L.; Kendall, William L.; Langtimm, Catherine Ann

    2014-01-01

    Despite intensive monitoring, temporary emigration from the sampling area can induce bias severe enough for managers to discard life-history parameter estimates toward the terminus of the times series (terminal bias). Under random temporary emigration unbiased parameters can be estimated with CJS models. However, unmodeled Markovian temporary emigration causes bias in parameter estimates and an unobservable state is required to model this type of emigration. The robust design is most flexible when modeling temporary emigration, and partial solutions to mitigate bias have been identified, nonetheless there are conditions were terminal bias prevails. Long-lived species with high adult survival and highly variable non-random temporary emigration present terminal bias in survival estimates, despite being modeled with the robust design and suggested constraints. Because this bias is due to uncertainty about the fate of individuals that are undetected toward the end of the time series, solutions should involve using additional information on survival status or location of these individuals at that time. Using simulation, we evaluated the performance of models that jointly analyze robust design data and an additional source of ancillary data (predictive covariate on temporary emigration, telemetry, dead recovery, or auxiliary resightings) in reducing terminal bias in survival estimates. The auxiliary resighting and predictive covariate models reduced terminal bias the most. Additional telemetry data was effective at reducing terminal bias only when individuals were tracked for a minimum of two years. High adult survival of long-lived species made the joint model with recovery data ineffective at reducing terminal bias because of small-sample bias. The naïve constraint model (last and penultimate temporary emigration parameters made equal), was the least efficient, though still able to reduce terminal bias when compared to an unconstrained model. Joint analysis of several

  20. Molecular cloaking of H2A.Z on mortal DNA chromosomes during nonrandom segregation.

    Science.gov (United States)

    Huh, Yang Hoon; Sherley, James L

    2011-10-01

    Although nonrandom sister chromatid segregation is a singular property of distributed stem cells (DSCs) that are responsible for renewing and repairing mature vertebrate tissues, both its cellular function and its molecular mechanism remain unknown. This situation persists in part because of the lack of facile methods for detecting and quantifying nonrandom segregating cells and for identifying chromosomes with immortal DNA strands, the cellular molecules that signify nonrandom segregation. During nonrandom segregation, at each mitosis, asymmetrically self-renewing DSCs continuously cosegregate to themselves the set of chromosomes that contain immortal DNA strands, which are the oldest DNA strands. Here, we report the discovery of a molecular asymmetry between segregating sets of immortal chromosomes and opposed mortal chromosomes (i.e., containing the younger set of DNA template strands) that constitutes a new convenient biomarker for detection of cells undergoing nonrandom segregation and direct delineation of chromosomes that bear immortal DNA strands. In both cells engineered with DSC-specific properties and ex vivo-expanded mouse hair follicle stem cells, the histone H2A variant H2A.Z shows specific immunodetection on immortal DNA chromosomes. Cell fixation analyses indicate that H2A.Z is present on mortal chromosomes as well but is cloaked from immunodetection, and the cloaking entity is acid labile. The H2A.Z chromosomal asymmetry produced by molecular cloaking provides a first direct assay for nonrandom segregation and for chromosomes with immortal DNA strands. It also seems likely to manifest an important aspect of the underlying mechanism(s) responsible for nonrandom sister chromatid segregation in DSCs.

  1. Data Clustering

    Science.gov (United States)

    Wagstaff, Kiri L.

    2012-03-01

    On obtaining a new data set, the researcher is immediately faced with the challenge of obtaining a high-level understanding from the observations. What does a typical item look like? What are the dominant trends? How many distinct groups are included in the data set, and how is each one characterized? Which observable values are common, and which rarely occur? Which items stand out as anomalies or outliers from the rest of the data? This challenge is exacerbated by the steady growth in data set size [11] as new instruments push into new frontiers of parameter space, via improvements in temporal, spatial, and spectral resolution, or by the desire to "fuse" observations from different modalities and instruments into a larger-picture understanding of the same underlying phenomenon. Data clustering algorithms provide a variety of solutions for this task. They can generate summaries, locate outliers, compress data, identify dense or sparse regions of feature space, and build data models. It is useful to note up front that "clusters" in this context refer to groups of items within some descriptive feature space, not (necessarily) to "galaxy clusters" which are dense regions in physical space. The goal of this chapter is to survey a variety of data clustering methods, with an eye toward their applicability to astronomical data analysis. In addition to improving the individual researcher’s understanding of a given data set, clustering has led directly to scientific advances, such as the discovery of new subclasses of stars [14] and gamma-ray bursts (GRBs) [38]. All clustering algorithms seek to identify groups within a data set that reflect some observed, quantifiable structure. Clustering is traditionally an unsupervised approach to data analysis, in the sense that it operates without any direct guidance about which items should be assigned to which clusters. There has been a recent trend in the clustering literature toward supporting semisupervised or constrained

  2. Functional redundancy patterns reveal non-random assembly rules in a species-rich marine assemblage.

    Directory of Open Access Journals (Sweden)

    Nicolas Guillemot

    Full Text Available The relationship between species and the functional diversity of assemblages is fundamental in ecology because it contains key information on functional redundancy, and functionally redundant ecosystems are thought to be more resilient, resistant and stable. However, this relationship is poorly understood and undocumented for species-rich coastal marine ecosystems. Here, we used underwater visual censuses to examine the patterns of functional redundancy for one of the most diverse vertebrate assemblages, the coral reef fishes of New Caledonia, South Pacific. First, we found that the relationship between functional and species diversity displayed a non-asymptotic power-shaped curve, implying that rare functions and species mainly occur in highly diverse assemblages. Second, we showed that the distribution of species amongst possible functions was significantly different from a random distribution up to a threshold of ∼90 species/transect. Redundancy patterns for each function further revealed that some functions displayed fast rates of increase in redundancy at low species diversity, whereas others were only becoming redundant past a certain threshold. This suggested non-random assembly rules and the existence of some primordial functions that would need to be fulfilled in priority so that coral reef fish assemblages can gain a basic ecological structure. Last, we found little effect of habitat on the shape of the functional-species diversity relationship and on the redundancy of functions, although habitat is known to largely determine assemblage characteristics such as species composition, biomass, and abundance. Our study shows that low functional redundancy is characteristic of this highly diverse fish assemblage, and, therefore, that even species-rich ecosystems such as coral reefs may be vulnerable to the removal of a few keystone species.

  3. Meta-analysis of non-randomized studies in interventional cardiology: a critical appraisal

    Directory of Open Access Journals (Sweden)

    Eliano Pio Navarese

    2009-12-01

    Full Text Available Utilisation of meta-analysis is becoming more and more common in interventional cardiology. The aim of this statistical approach is to collect a large number of patients from randomized clinical studies and nonrandomized registries in order to obtain a pooled estimate of the results. Nevertheless, simply pooling these results without a correct methodological approach can easily lead to biased conclusions. In this report we analyse the possible methodological drawbacks of such an approach and we suggest a simplified check-list of items to be considered in the effort of building-up a meta-analysis from non-randomized studies.

  4. Non-random structures in universal compression and the Fermi paradox

    Science.gov (United States)

    Gurzadyan, A. V.; Allahverdyan, A. E.

    2016-02-01

    We study the hypothesis of information panspermia assigned recently among possible solutions of the Fermi paradox ("where are the aliens?"). It suggests that the expenses of alien signaling can be significantly reduced, if their messages contained compressed information. To this end we consider universal compression and decoding mechanisms ( e.g. the Lempel-Ziv-Welch algorithm) that can reveal non-random structures in compressed bit strings. The efficiency of the Kolmogorov stochasticity parameter for detection of non-randomness is illustrated, along with the Zipf's law. The universality of these methods, i.e. independence from data details, can be principal in searching for intelligent messages.

  5. Non-random structures in universal compression and the Fermi paradox

    CERN Document Server

    Gurzadyan, A V

    2016-01-01

    We study the hypothesis of information panspermia assigned recently among possible solutions of the Fermi paradox ("where are the aliens?"). It suggests that the expenses of alien signaling can be significantly reduced, if their messages contain compressed information. To this end we consider universal compression and decoding mechanisms (e.g. the Lempel-Ziv-Welch algorithm) that can reveal non-random structures in compressed bit strings. The efficiency of Kolmogorov stochasticity parameter for detection of non-randomness is illustrated, along with the Zipf's law. The universality of these methods, i.e. independence on data details, can be principal in searching for intelligent messages.

  6. The quality of control groups in nonrandomized studies published in the Journal of Hand Surgery.

    Science.gov (United States)

    Johnson, Shepard P; Malay, Sunitha; Chung, Kevin C

    2015-01-01

    To evaluate control group selection in nonrandomized studies published in the Journal of Hand Surgery American (JHS). We reviewed all papers published in JHS in 2013 to identify studies that used nonrandomized control groups. Data collected included type of study design and control group characteristics. We then appraised studies to determine whether authors discussed confounding and selection bias and how they controlled for confounding. Thirty-seven nonrandomized studies were published in JHS in 2013. The source of control was either the same institution as the study group, a different institution, a database, or not provided in the manuscript. Twenty-nine (78%) studies statistically compared key characteristics between control and study group. Confounding was controlled with matching, exclusion criteria, or regression analysis. Twenty-two (59%) papers explicitly discussed the threat of confounding and 18 (49%) identified sources of selection bias. In our review of nonrandomized studies published in JHS, papers had well-defined controls that were similar to the study group, allowing for reasonable comparisons. However, we identified substantial confounding and bias that were not addressed as explicit limitations, which might lead the reader to overestimate the scientific validity of the data. Incorporating a brief discussion of control group selection in scientific manuscripts should help readers interpret the study more appropriately. Authors, reviewers, and editors should strive to address this component of clinical importance. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  7. A nonrandomized comparison of stapes surgery with and without a vein graft in patients with otosclerosis

    NARCIS (Netherlands)

    Bittermann, A.J.; Vincent, R.; Rovers, M.M.; Heijden, G.J. van der; Tange, R.A.; Dreschler, W.A.; Grolman, W.

    2013-01-01

    OBJECTIVE: To evaluate the effectiveness of primary stapes surgery with and without a vein graft in patients with otosclerosis and to determine the differences in the postoperative gain in air-bone gap (ABG) and air-conduction (AC). STUDY DESIGN: A nonrandomized multicenter clinical evaluation.

  8. Use versus Nonuse of Repeater Examinees in Common Item Linear Equating with Nonrandom Groups.

    Science.gov (United States)

    Cope, Ronald T.

    This study considers the use of repeaters when test equating. The subjects consist of five groups of applicants to a professional certification program. Each group comprises first time examinees and repeaters. The procedures include a common item linear equating with nonrandom groups, use of equating chains, and the use of total examinee group…

  9. Quantitative assessment of unobserved confounding is mandatory in nonrandomized intervention studies

    NARCIS (Netherlands)

    Groenwold, R H H; Hak, E; Hoes, A W

    2009-01-01

    OBJECTIVE: In nonrandomized intervention studies unequal distribution of patient characteristics in the groups under study may hinder comparability of prognosis and therefore lead to confounding bias. Our objective was to review methods to control for observed confounding, as well as unobserved conf

  10. Systematic reviews incorporating evidence from nonrandomized study designs: reasons for caution when estimating health effects.

    NARCIS (Netherlands)

    Reeves, B.C.; Binsbergen, J.J. van; Weel, C. van

    2005-01-01

    Systematic reviews that include nonrandomized studies (NRS) face a number of logistical challenges. However, the greatest threat to the validity of such reviews arises from the differing susceptibility of randomized controlled trials (RCTs) and NRS to selection bias. Groups compared in NRS are unlik

  11. Checklists of Methodological Issues for Review Authors to Consider When Including Non-Randomized Studies in Systematic Reviews

    Science.gov (United States)

    Wells, George A.; Shea, Beverley; Higgins, Julian P. T.; Sterne, Jonathan; Tugwell, Peter; Reeves, Barnaby C.

    2013-01-01

    Background: There is increasing interest from review authors about including non-randomized studies (NRS) in their systematic reviews of health care interventions. This series from the Ottawa Non-Randomized Studies Workshop consists of six papers identifying methodological issues when doing this. Aim: To format the guidance from the preceding…

  12. Strategies for improving postpartum contraceptive use: evidence from non-randomized studies.

    Science.gov (United States)

    Lopez, Laureen M; Grey, Thomas W; Chen, Mario; Hiller, Janet E

    2014-11-27

    Nearly two-thirds of women in their first postpartum year have an unmet need for family planning. Adolescents often have repeat pregnancies within a year of giving birth. Women may receive counseling on family planning both antepartum and postpartum. Decisions about contraceptive use made right after counseling may differ considerably from actual postpartum use. In earlier work, we found limited evidence of effectiveness from randomized trials on postpartum contraceptive counseling. For educational interventions, non-randomized studies may be conducted more often than randomized trials. We reviewed non-randomized studies of educational strategies to improve postpartum contraceptive use. Our intent was to examine associations between specific interventions and postpartum contraceptive use or subsequent pregnancy. We searched for eligible non-randomized studies until 3 November 2014. Sources included CENTRAL, PubMed, POPLINE, and Web of Science. We also sought current trials via ClinicalTrials.gov and ICTRP. For additional citations, we examined reference lists of relevant reports and reviews. The studies had to be comparative, i.e., have intervention and comparison groups. The educational component could be counseling or another behavioral strategy to improve contraceptive use among postpartum women. The intervention had to include contact within six weeks postpartum. The comparison condition could be another behavioral strategy to improve contraceptive use, usual care, other health education, or no intervention. Our primary outcomes were postpartum contraceptive use and subsequent pregnancy. Two authors evaluated abstracts for eligibility and extracted data from included studies. We computed the Mantel-Haenszel odds ratio (OR) for dichotomous outcomes and the mean difference (MD) for continuous measures, both with 95% Confidence Intervals (CI). Where studies used adjusted analyses for continuous outcomes, we presented the results as reported by the investigators

  13. Garnet polycrystals and the significance of clustered crystallization

    Science.gov (United States)

    Whitney, Donna L.; Seaton, Nicholas C. A.

    2010-10-01

    Polycrystalline garnets are common in metamorphic rocks and may form as a result of close spacing of nuclei (if clustering is early) or impingement of larger grains (if clustering occurs later in the growth history). The timing of clustering relative to garnet growth is relevant to understanding the formation and evolution of porphyroblasts and evaluating the significance (if any) of clustering. Electron backscattered diffraction (EBSD) analysis of garnet-bearing metamorphic rocks reveals the presence of polycrystalline garnet in nine localities examined in this study: the northern Appalachians (Vermont, Maine, New York, USA); North American Cordillera (North Cascades Range, Washington; Snake Range, Nevada, USA); western Rocky Mountains (British Columbia, Canada); southern Menderes Massif (Turkey); Santander Massif (Colombia); and the Sanandaj-Sirjan zone (Hamadan, Iran). In some samples, polycrystals comprise ~20-30% of garnets analyzed, and chemical and textural evidence suggests that early coalescence of garnet polycrystals is common. Some early-coalescing polycrystals exhibit growth zoning that is concentric about the geometric center of the polycrystal. In thin section, these garnets may be undetectable as polycrystals based on morphology or zoning. In some polycrystals, zoning is unrelated to the location of internal grain boundaries; in others, Fe-Mn-Mg zoning has a different pattern than that of Ca; zoning patterns may vary on the scale of a single thin section. In addition, some polycrystals are characterized by high-angle misorientation boundaries that may be in special (non-random) orientations, an observation that indicates that these polycrystals are not random clusters of grains. The presence of internal grain boundaries may affect diffusion pathways and length scales, and may facilitate communication of porphyroblast interiors with matrix phases, thereby influencing reaction history of the rock and the composition/zoning of garnet.

  14. Management of cluster headache

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer C; Jensen, Rigmor H

    2012-01-01

    and agitation. Patients may have up to eight attacks per day. Episodic cluster headache (ECH) occurs in clusters of weeks to months duration, whereas chronic cluster headache (CCH) attacks occur for more than 1 year without remissions. Management of cluster headache is divided into acute attack treatment....... In drug-resistant CCH, neuromodulation with either occipital nerve stimulation or deep brain stimulation of the hypothalamus is an alternative treatment strategy. For most cluster headache patients there are fairly good treatment options both for acute attacks and for prophylaxis. The big problem...

  15. Cortical atrophy patterns in multiple sclerosis are non-random and clinically relevant.

    Science.gov (United States)

    Steenwijk, Martijn D; Geurts, Jeroen J G; Daams, Marita; Tijms, Betty M; Wink, Alle Meije; Balk, Lisanne J; Tewarie, Prejaas K; Uitdehaag, Bernard M J; Barkhof, Frederik; Vrenken, Hugo; Pouwels, Petra J W

    2016-01-01

    cortical atrophy in multiple sclerosis occurs largely in a non-random manner and develops (at least partly) according to distinct anatomical patterns. In addition, these cortical atrophy patterns showed stronger associations with clinical (especially cognitive) dysfunction than global cortical atrophy.

  16. Meta-analyses including non-randomized studies of therapeutic interventions: a methodological review

    Directory of Open Access Journals (Sweden)

    Timor Faber

    2016-03-01

    Full Text Available Abstract Background There is an increasing number of meta-analyses including data from non-randomized studies for therapeutic evaluation. We aimed to systematically assess the methods used in meta-analyses including non-randomized studies evaluating therapeutic interventions. Methods For this methodological review, we searched MEDLINE via PubMed, from January 1, 2013 to December 31, 2013 for meta-analyses including at least one non-randomized study evaluating therapeutic interventions. Etiological assessments and meta-analyses with no comparison group were excluded. Two reviewers independently assessed the general characteristics and key methodological components of the systematic review process and meta-analysis methods. Results One hundred eighty eight meta-analyses were selected: 119 included both randomized controlled trials (RCTs and non-randomized studies of interventions (NRSI and 69 only NRSI. Half of the meta-analyses (n = 92, 49 % evaluated non-pharmacological interventions. “Grey literature” was searched for 72 meta-analyses (38 %. An assessment of methodological quality or risk of bias was reported in 135 meta-analyses (72 % but this assessment considered the risk of confounding bias in only 33 meta-analyses (18 %. In 130 meta-analyses (69 %, the design of each NRSI was not clearly specified. In 131 (70 %, whether crude or adjusted estimates of treatment effect for NRSI were combined was unclear or not reported. Heterogeneity across studies was assessed in 182 meta-analyses (97 % and further explored in 157 (84 %. Reporting bias was assessed in 127 (68 %. Conclusions Some key methodological components of the systematic review process—search for grey literature, description of the type of NRSI included, assessment of risk of confounding bias and reporting of whether crude or adjusted estimates were combined—are not adequately carried out or reported in meta-analyses including NRSI.

  17. Implications of nonrandom seed abscission and global stilling for migration of wind-dispersed plant species.

    Science.gov (United States)

    Thompson, Sally E; Katul, Gabriel G

    2013-06-01

    Migration of plant populations is a potential survival response to climate change that depends critically on seed dispersal. Biological and physical factors determine dispersal and migration of wind-dispersed species. Recent field and wind tunnel studies demonstrate biological adaptations that bias seed release toward conditions of higher wind velocity, promoting longer dispersal distances and faster migration. However, another suite of international studies also recently highlighted a global decrease in near-surface wind speeds, or 'global stilling'. This study assessed the implications of both factors on potential plant population migration rates, using a mechanistic modeling framework. Nonrandom abscission was investigated using models of three seed release mechanisms: (i) a simple drag model; (ii) a seed deflection model; and (iii) a 'wear and tear' model. The models generated a single functional relationship between the frequency of seed release and statistics of the near-surface wind environment, independent of the abscission mechanism. An Inertial-Particle, Coupled Eulerian-Lagrangian Closure model (IP-CELC) was used to investigate abscission effects on seed dispersal kernels and plant population migration rates under contemporary and potential future wind conditions (based on reported global stilling trends). The results confirm that nonrandom seed abscission increased dispersal distances, particularly for light seeds. The increases were mitigated by two physical feedbacks: (i) although nonrandom abscission increased the initial acceleration of seeds from rest, the sensitivity of the seed dispersal to this initial condition declined as the wind speed increased; and (ii) while nonrandom abscission increased the mean dispersal length, it reduced the kurtosis of seasonal dispersal kernels, and thus the chance of long-distance dispersal. Wind stilling greatly reduced the modeled migration rates under biased seed release conditions. Thus, species that require

  18. Composition, richness and nonrandom assembly of culturable bacterial-microfungal communities in floral nectar of Mediterranean plants.

    Science.gov (United States)

    Alvarez-Pérez, Sergio; Herrera, Carlos M

    2013-03-01

    The recent upsurge of interest in the role of floral nectar as a habitat for microorganisms has led to some detailed analyses of nectarivorous yeasts. In contrast, very little is known on the occurrence and diversity of nectar-dwelling bacteria, and bacterial-fungal interactions within nectar remain unexplored. In this work, we studied both the culturable bacteria and microfungi found in the floral nectar of wild Mediterranean plants. In general, bacteria and yeasts were found coexisting in nectar more often than would be expected by chance, and such positive association persisted after accounting for phylogenetic nonindependence of the plant species surveyed. Metschnikowia species were confirmed as the main fungal components of nectar communities, and Acinetobacter was identified as the main bacterial taxa. Finally, individual Operational Taxonomic Units (OTUs) were found to co-occur less frequently than predicted by random expectations. There existed, however, some pairwise associations between OTUs that seemed to account for the general pattern of positive bacteria-yeasts coexistence. We conclude that the culturable communities of nectar microorganisms associated with wild Mediterranean plants are nonrandom assemblages of bacterial and yeast species. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  19. Non-random distribution of amino acids in the transmembrane segments of human type I single span membrane proteins.

    Science.gov (United States)

    Landolt-Marticorena, C; Williams, K A; Deber, C M; Reithmeier, R A

    1993-02-05

    The distribution of amino acids in the transmembrane segments and flanking regions of 115 human type I single span (amino terminus extracellular and carboxyl terminus cytosolic) plasma membrane proteins was found to be non-random. In this sample, Ile was preferentially localized to the amino-terminal region of the hydrophobic transmembrane segments, followed by Val, while Leu predominated in the carboxyl-terminal half of the segment. Although Gly residues were preferentially located in the transmembrane segment, this residue was excluded from the carboxyl-terminal and adjacent boundary regions. Aromatic residues (Tyr, Trp and Phe) occurred preferentially at the cytoplasmic boundary, with Trp also favored at the extracellular boundary. The extracellular flanking sequence amino-terminal to the transmembrane segment was enriched in residues predicted to initiate helix formation (Pro, Asn and Ser), while Arg and Lys were enriched in the cytoplasmic flank where they may function as topological determinants. The positional preferences of these particular amino acids within the transmembrane segment and flanking regions suggests that, in addition to lipid-protein interactions, these residues may participate in specific protein-protein interactions. A consensus sequence motif for type I membrane proteins is proposed and its role in the biosynthesis, folding, assembly and function of these segments is discussed.

  20. Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes.

    Science.gov (United States)

    Stimpson, Kaitlin M; Song, Ihn Young; Jauch, Anna; Holtgreve-Grez, Heidi; Hayden, Karen E; Bridger, Joanna M; Sullivan, Beth A

    2010-08-12

    Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extra-chromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.

  1. Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes.

    Directory of Open Access Journals (Sweden)

    Kaitlin M Stimpson

    2010-08-01

    Full Text Available Genome rearrangement often produces chromosomes with two centromeres (dicentrics that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extra-chromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.

  2. Effectiveness and Safety of Acupuncture for Poststroke Dysphagia: Study Protocol for a Pragmatic Multicenter Nonrandomized Controlled Trial

    Science.gov (United States)

    Guo, Yuan Qi

    2017-01-01

    Background. Dysphagia is one of the most common complications of stroke. Acupuncture is widely employed to treat poststroke dysphagia in East Asia. No evidence is established to support such treatment approach. This proposed study aims to evaluate the effectiveness and safety of acupuncture for the treatment of poststroke dysphagia. Methods and Design. This is a multicenter, pragmatic, single-blinded, nonrandomized controlled clinical trial. A total of 140 eligible patients will be enrolled in the study. Subjects who are eligible in study but refuse to have acupuncture treatment will be put on the no-acupuncture control arm. Both groups of patients will receive standard routine care, while the patients of intervention group will receive add-on standardized acupuncture treatment. Each participant in intervention group will receive a total of 24 sessions of acupuncture treatment (three times per week). The primary outcome measure is the Royal Brisbane Hospital Outcome Measure for Swallowing (RBHOMS). Secondary outcome measures include functional oral intake scale, swallow quality-of-life questionnaire in Chinese version, BMI of the participant, and adverse events. All outcome measures will be assessed at baseline, at the end of acupuncture treatment (month 2), and at two months after treatment (month 4). Ethics and Dissemination. The ethics approval of clinical research study was granted by the Research Ethics Committee of both New Territories East and West Cluster of Hong Kong. Written informed consent will be obtained from all participants and the study will be undertaken according to the ICH-GCP Guidelines. Trial Registration. This trial is registered with chictr.org (registration number: ChiCTR-TRC-12002621 and registration date: 2012-10-26). PMID:28246537

  3. A systematic review of nonrandomized controlled trials on the curative effects of aquatic exercise

    Directory of Open Access Journals (Sweden)

    Kamioka H

    2011-03-01

    Full Text Available Hiroharu Kamioka1, Kiichiro Tsutani2, Yoshiteru Mutoh3, Hiroyasu Okuizum4, Miho Ohta5, Shuichi Handa4, Shinpei Okada6, Jun Kitayuguchi7, Masamitsu Kamada7, Nobuyoshi Shiozawa8, Sang-Jun Park4, Takuya Honda4, Shoko Moriyama41Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan; 2Department of Drug Policy and Management, Graduate School of Pharmaceutical Sciences, 3Department of Physical and Health Education, Graduate School of Education, The University of Tokyo, Tokyo, Japan; 4Mimaki Onsen (Spa Clinic, Tomi City, Japan; 5Laboratory of Aqua, Health, and Sports Medicine, 6Physical Education and Medicine Research Foundation, Nagano, Japan; 7Physical Education and Medicine Research Center Unnan, Unnan City, Japan; 8Department of Longevity and Social Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, JapanBackground: The objectives of this review were to integrate the evidence of curative effects through aquatic exercise and assess the quality of studies based on a review of nonrandomized controlled trials (nRCTs.Methods: Study design was a systematic review of nonrandomized controlled trials. Trials were eligible if they were nonrandomized clinical trials. Studies included one treatment group in which aquatic exercise was applied. We searched the following databases from 2000 up to July 20, 2009: MEDLINE via PubMed, CINAHL, and Ichushi-Web.Results: Twenty-one trials met all inclusion criteria. Languages included were English (N = 9, Japanese (N = 11, and Korean (N = 1. Target diseases were knee and/or hip osteoarthritis, poliomyelitis, chronic kidney disease, discomforts of pregnancy, cardiovascular diseases, and rotator cuff tears. Many studies on nonspecific disease (healthy participants were included. All studies reported significant effectiveness in at least one or more outcomes. However results of evaluations with the TREND and CLEAR-NPT checklists generally

  4. Patterns of Nonrandom Mating Within and Across 11 Major Psychiatric Disorders

    Science.gov (United States)

    Nordsletten, Ashley E.; Larsson, Henrik; Crowley, James J.; Almqvist, Catarina; Lichtenstein, Paul; Mataix-Cols, David

    2016-01-01

    IMPORTANCE Psychiatric disorders are heritable, polygenic traits, which often share risk alleles and for which nonrandom mating has been suggested. However, despite the potential etiological implications, the scale of nonrandom mating within and across major psychiatric conditions remains unclear. OBJECTIVE To quantify the nature and extent of nonrandom mating within and across a broad range of psychiatric conditions at the population level. DESIGN, SETTING, AND PARTICIPANTS Population-based cohort using Swedish population registers. Participants were all Swedish residents with a psychiatric diagnosis of interest (attention-deficit/hyperactivity disorder, autism spectrum disorder, schizophrenia, bipolar disorder, major depression, generalized anxiety disorder, agoraphobia, social phobia, obsessive-compulsive disorder, anorexia, or substance abuse), along with their mates. Individuals with select nonpsychiatric disorders (Crohn’s disease, type 1 and type 2 diabetes mellitus, multiple sclerosis, or rheumatoid arthritis) were included for comparison. General population samples were also derived and matched 1:5 with each case proband. Inpatient and outpatient diagnostic data were derived from the Swedish National Patient Register (1973-2009), with analyses conducted between June 2014 and May 2015. MAIN OUTCOMES AND MEASURES Correlation in the diagnostic status of mates both within and across disorders. Conditional logistic regression was used to quantify the odds of each diagnosis in the mates of cases relative to matched population controls. RESULTS Across cohorts, data corresponded to 707 263 unique case individuals, with women constituting 45.7% of the full population. Positive correlations in diagnostic status were evident between mates. Within-disorder correlations were marginally higher (range, 0.11-0.48) than cross-disorder correlations (range, 0.01-0.42). Relative to matched populations, the odds of psychiatric case probands having an affected mate were

  5. Chemical evolution of star clusters

    OpenAIRE

    van Loon, Jacco Th.

    2009-01-01

    I discuss the chemical evolution of star clusters, with emphasis on old globular clusters, in relation to their formation histories. Globular clusters clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of globular clusters in dwarf galaxies has been suggested, present-day dwarf galaxi...

  6. The Self-Made Puzzle: Integrating Self-Assembly and Pattern Formation Under Non-Random Genetic Regulation

    Science.gov (United States)

    Doursat, René

    On the one hand, research in self-assembling systems, whether natural or artificial, has traditionally focused on pre-existing components endowed with fixed shapes. Biological development, by contrast, dynamically creates new cells that acquire selective adhesion properties through differentiation induced by their neighborhood. On the other hand, pattern formation phenomena are generally construed as orderly states of activity on top of a continuous 2-D or 3-D substrate. Yet, again, the spontaneous patterning of an organism into domains of gene expression arises within a multicellular medium in perpetual expansion and reshaping. Finally, both phenomena are often thought in terms of stochastic events, whether mixed components that randomly collide in self-assembly, or spots and stripes that occur unpredictably from instabilities in pattern formation. Here too, these notions need significant revision if they are to be extended and applied to embryogenesis. Cells are not randomly mixed but pre-positioned where cell division occurs. Genetic identity domains are not randomly distributed but highly regulated in number and position. In this work, I present a computational model of program-mable and reproducible artificial morphogenesis that integrates self-assembly and pattern formation under the control of a nonrandom gene regulatory network. The specialized properties of cells (division, adhesion, migration) are determined by the gene expression domains to which they belong, while at the same time these domains further expand and segment into subdomains due to the self-assembly of specialized cells. Through this model, I also promote a new discipline, embryomorphic engineering to solve the paradox of "meta-designing" decentralized, autonomous systems.

  7. Non-random mate choice in humans: insights from a genome scan.

    Science.gov (United States)

    Laurent, R; Toupance, B; Chaix, R

    2012-02-01

    Little is known about the genetic factors influencing mate choice in humans. Still, there is evidence for non-random mate choice with respect to physical traits. In addition, some studies suggest that the Major Histocompatibility Complex may affect pair formation. Nowadays, the availability of high density genomic data sets gives the opportunity to scan the genome for signatures of non-random mate choice without prior assumptions on which genes may be involved, while taking into account socio-demographic factors. Here, we performed a genome scan to detect extreme patterns of similarity or dissimilarity among spouses throughout the genome in three populations of African, European American, and Mexican origins from the HapMap 3 database. Our analyses identified genes and biological functions that may affect pair formation in humans, including genes involved in skin appearance, morphogenesis, immunity and behaviour. We found little overlap between the three populations, suggesting that the biological functions potentially influencing mate choice are population specific, in other words are culturally driven. Moreover, whenever the same functional category of genes showed a significant signal in two populations, different genes were actually involved, which suggests the possibility of evolutionary convergences.

  8. Cluster headache

    Science.gov (United States)

    Histamine headache; Headache - histamine; Migrainous neuralgia; Headache - cluster; Horton's headache; Vascular headache - cluster ... A cluster headache begins as a severe, sudden headache. The headache commonly strikes 2 to 3 hours after you fall ...

  9. Cluster Forests

    CERN Document Server

    Yan, Donghui; Jordan, Michael I

    2011-01-01

    Inspired by Random Forests (RF) in the context of classification, we propose a new clustering ensemble method---Cluster Forests (CF). Geometrically, CF randomly probes a high-dimensional data cloud to obtain "good local clusterings" and then aggregates via spectral clustering to obtain cluster assignments for the whole dataset. The search for good local clusterings is guided by a cluster quality measure $\\kappa$. CF progressively improves each local clustering in a fashion that resembles the tree growth in RF. Empirical studies on several real-world datasets under two different performance metrics show that CF compares favorably to its competitors. Theoretical analysis shows that the $\\kappa$ criterion is shown to grow each local clustering in a desirable way---it is "noise-resistant." A closed-form expression is obtained for the mis-clustering rate of spectral clustering under a perturbation model, which yields new insights into some aspects of spectral clustering.

  10. Star Clusters

    OpenAIRE

    Gieles, M.

    1993-01-01

    Star clusters are observed in almost every galaxy. In this thesis we address several fundamental problems concerning the formation, evolution and disruption of star clusters. From observations of (young) star clusters in the interacting galaxy M51, we found that clusters are formed in complexes of stars and star clusters. These complexes share similar properties with giant molecular clouds, from which they are formed. Many (70%) of the young clusters will not survive the fist 10 Myr, due to t...

  11. On clusters and clustering from atoms to fractals

    CERN Document Server

    Reynolds, PJ

    1993-01-01

    This book attempts to answer why there is so much interest in clusters. Clusters occur on all length scales, and as a result occur in a variety of fields. Clusters are interesting scientifically, but they also have important consequences technologically. The division of the book into three parts roughly separates the field into small, intermediate, and large-scale clusters. Small clusters are the regime of atomic and molecular physics and chemistry. The intermediate regime is the transitional regime, with its characteristics including the onset of bulk-like behavior, growth and aggregation, a

  12. Disentangling Porterian Clusters

    DEFF Research Database (Denmark)

    Jagtfelt, Tue

    This dissertation investigates the contemporary phenomenon of industrial clusters based on the work of Michael E. Porter, the central progenitor and promoter of the cluster notion. The dissertation pursues two central questions: 1) What is a cluster? and 2) How could Porter’s seemingly fuzzy......, contested theory become so widely disseminated and applied as a normative and prescriptive strategy for economic development? The dissertation traces the introduction of the cluster notion into the EU’s Lisbon Strategy and demonstrates how its inclusion originates from Porter’s colleagues: Professor Örjan...... Sölvell, Dr. Christian Ketels and Dr. Göran Lindqvist. Taking departure in Porter’s works and the cluster literature, the dissertations shows a considerable paradigmatic shift has occurred from the first edition of Nations to the present state of cluster cooperation. To elaborate on this change...

  13. Cluster Management Institutionalization

    DEFF Research Database (Denmark)

    Normann, Leo; Agger Nielsen, Jeppe

    2015-01-01

    This article explores a new management form – cluster management – in Danish public sector day care. Although cluster management has been widely adopted in Danish day care at the municipality level, it has attracted only sparse research attention. We use theoretical insights from Scandinavian...... institutionalism together with a longitudinal case-based inquiry into how cluster management has entered and penetrated the management practices of day care in Denmark. We demonstrate how cluster management became widely adopted in the day care field not only because of its intrinsic properties but also because...... of how it was legitimized as a “ready-to-use” management model. Further, our account reveals how cluster management translated into considerably different local variants as it travelled into specific organizations. However, these processes have not occurred sequentially with cluster management first...

  14. Cluster Management Institutionalization

    DEFF Research Database (Denmark)

    Normann, Leo; Agger Nielsen, Jeppe

    2015-01-01

    of how it was legitimized as a “ready-to-use” management model. Further, our account reveals how cluster management translated into considerably different local variants as it travelled into specific organizations. However, these processes have not occurred sequentially with cluster management first......This article explores a new management form – cluster management – in Danish public sector day care. Although cluster management has been widely adopted in Danish day care at the municipality level, it has attracted only sparse research attention. We use theoretical insights from Scandinavian...... institutionalism together with a longitudinal case-based inquiry into how cluster management has entered and penetrated the management practices of day care in Denmark. We demonstrate how cluster management became widely adopted in the day care field not only because of its intrinsic properties but also because...

  15. Non-random food-web assembly at habitat edges increases connectivity and functional redundancy.

    Science.gov (United States)

    Peralta, Guadalupe; Frost, Carol M; Didham, Raphael K; Rand, Tatyana A; Tylianakis, Jason M

    2017-04-01

    Habitat fragmentation dramatically alters the spatial configuration of landscapes, with the creation of artificial edges affecting community structure and dynamics. Despite this, it is not known how the different food webs in adjacent habitats assemble at their boundaries. Here we demonstrate that the composition and structure of herbivore-parasitoid food webs across edges between native and plantation forests are not randomly assembled from those of the adjacent communities. Rather, elevated proportions of abundant, interaction-generalist parasitoid species at habitat edges allowed considerable interaction rewiring, which led to higher linkage density and less modular networks, with higher parasitoid functional redundancy. This was despite high overlap in host composition between edges and interiors. We also provide testable hypotheses for how food webs may assemble between habitats with lower species overlap. In an increasingly fragmented world, non-random assembly of food webs at edges may increasingly affect community dynamics at the landscape level.

  16. Myasis occuring in a neonate

    Science.gov (United States)

    Obasa, Temitope O.; Sowunmi, Funmilola Olusola

    2012-01-01

    Myasis is the infestation of skin by larvae or maggots of a variety of flies. It is a condition that occurs more commonly in adults who are living and/or have visited tropical countries. It rarely occurs in neonates, and even when seen, only few larvae are extracted. This case report describes myasis occurring in an 11-day-old female who had 47 larvae in her skin. PMID:23355934

  17. Myasis occuring in a neonate

    Directory of Open Access Journals (Sweden)

    Temitope O. Obasa

    2012-12-01

    Full Text Available Myasis is the infestation of skin by larvae or maggots of a variety of flies. It is a condition that occurs more commonly in adults who are living and/or have visited tropical countries. It rarely occurs in neonates, and even when seen, only few larvae are extracted. This case report describes myasis occurring in an 11-day-old female who had 47 larvae in her skin.

  18. Dense neuron clustering explains connectivity statistics in cortical microcircuits.

    Directory of Open Access Journals (Sweden)

    Vladimir V Klinshov

    Full Text Available Local cortical circuits appear highly non-random, but the underlying connectivity rule remains elusive. Here, we analyze experimental data observed in layer 5 of rat neocortex and suggest a model for connectivity from which emerge essential observed non-random features of both wiring and weighting. These features include lognormal distributions of synaptic connection strength, anatomical clustering, and strong correlations between clustering and connection strength. Our model predicts that cortical microcircuits contain large groups of densely connected neurons which we call clusters. We show that such a cluster contains about one fifth of all excitatory neurons of a circuit which are very densely connected with stronger than average synapses. We demonstrate that such clustering plays an important role in the network dynamics, namely, it creates bistable neural spiking in small cortical circuits. Furthermore, introducing local clustering in large-scale networks leads to the emergence of various patterns of persistent local activity in an ongoing network activity. Thus, our results may bridge a gap between anatomical structure and persistent activity observed during working memory and other cognitive processes.

  19. Weighted Clustering

    DEFF Research Database (Denmark)

    Ackerman, Margareta; Ben-David, Shai; Branzei, Simina

    2012-01-01

    We investigate a natural generalization of the classical clustering problem, considering clustering tasks in which different instances may have different weights.We conduct the first extensive theoretical analysis on the influence of weighted data on standard clustering algorithms in both...... the partitional and hierarchical settings, characterizing the conditions under which algorithms react to weights. Extending a recent framework for clustering algorithm selection, we propose intuitive properties that would allow users to choose between clustering algorithms in the weighted setting and classify...

  20. Development of an interventional pain management specific instrument for methodologic quality assessment of nonrandomized studies of interventional techniques.

    Science.gov (United States)

    Manchikanti, Laxmaiah; Hirsch, Joshua A; Heavner, James E; Cohen, Steven P; Benyamin, Ramsin M; Sehgal, Nalini; Falco, Frank J E; Vallejo, Ricardo; Onyewu, Obi; Zhu, Jie; Kaye, Alan D; Boswell, Mark V; Helm, Standiford; Candido, Kenneth D; Diwan, Sudhir; Simopoulos, Thomas T; Singh, Vijay; Pampati, Vidyasagar; Racz, Gabor B; Raj, P Prithvi

    2014-01-01

    The major component of a systematic review is assessment of the methodologic quality and bias of randomized and nonrandomized trials. While there are multiple instruments available to assess the methodologic quality and bias for randomized controlled trials (RCTs), there is a lack of extensively utilized instruments for observational studies, specifically for interventional pain management (IPM) techniques. Even Cochrane review criteria for randomized trials is considered not to be a "gold standard," but merely an indication of the current state of the art review methodology. Recently a specific instrument to assess the methodologic quality of randomized trials has been developed for interventional techniques. Our objective was to develop an IPM specific instrument to assess the methodological quality of nonrandomized trials or observational studies of interventional techniques. The item generation for the instrument was based on a definition of quality, to the extent to which the design and conduct of the trial were congruent with the objectives of the study. Applicability was defined as the extent to which procedures produced by the study could be applied using contemporary IPM techniques. Multiple items based on Cochrane review criteria and Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment for Nonrandomized Studies (IPM-QRBNR) were utilized. A total of 16 items were developed which formed the IPM-QRBNR tool. The assessment was performed in multiple stages. The final assessment was 4 nonrandomized studies. The inter-rater agreement was moderate to good for IPM-QRBNR criteria. Limited validity or accuracy assessment of the instrument and the large number of items to be scored were limitations. We have developed a new comprehensive instrument to assess the methodological quality of nonrandomized studies of interventional techniques. This instrument provides extensive information specific to interventional

  1. Validation of the k-filtering technique for a signal composed of random phase plane waves and non-random coherent structures

    Directory of Open Access Journals (Sweden)

    O. W. Roberts

    2014-08-01

    Full Text Available Recent observations of astrophysical magnetic fields have shown the presence of fluctuations being wave-like (propagating in the plasma frame and those described as being structure-like (advected by the plasma bulk velocity. Typically with single spacecraft missions it is impossible to differentiate between these two fluctuations, due to the inherent spatio-temporal ambiguity associated with a single point measurement. However missions such as Cluster which contain multiple spacecraft have allowed temporal and spatial changes to be resolved, with techniques such as the k-filtering technique. While this technique does not assume Taylor's hypothesis as is necessary with single spacecraft missions, it does require weak stationarity of the time series, and that the fluctuations can be described by a superposition of plane waves with random phase. In this paper we test whether the method can cope with a synthetic signal which is composed of a combination of non-random phase coherent structures with a mean radius d and a mean separation λ, as well as plane waves with random phase.

  2. Intravenous Immunoglobulin Therapy in Pediatric Narcolepsy: A Nonrandomized, Open-Label, Controlled, Longitudinal Observational Study

    Science.gov (United States)

    Lecendreux, Michel; Berthier, Johanna; Corny, Jennifer; Bourdon, Olivier; Dossier, Claire; Delclaux, Christophe

    2017-01-01

    Study Objectives: Previous case reports of intravenous immunoglobulins (IVIg) in pediatric narcolepsy have shown contradictory results. Methods: This was a nonrandomized, open-label, controlled, longitudinal observational study of IVIg use in pediatric narcolepsy with retrospective data collection from medical files obtained from a single pediatric national reference center for the treatment of narcolepsy in France. Of 56 consecutively referred patients with narcolepsy, 24 received IVIg (3 infusions administered at 1-mo intervals) in addition to standard care (psychostimulants and/or anticataplectic agents), and 32 continued on standard care alone (controls). Results: For two patients in each group, medical files were unavailable. Of the 22 IVIg patients, all had cerebrospinal fluid (CSF) hypocretin ≤ 110 pg/mL and were HLA-DQB1*06:02 positive. Of the 30 control patients, 29 were HLA-DQB1*06:02 positive and of those with available CSF measurements, all 12 had hypocretin ≤ 110 pg/mL. Compared with control patients, IVIg patients had shorter disease duration, shorter latency to sleep onset, and more had received H1N1 vaccination. Mean (standard deviation) follow-up length was 2.4 (1.1) y in the IVIg group and 3.9 (1.7) y in controls. In multivariate-adjusted linear mixed-effects analyses of change from baseline in Ullanlinna Narcolepsy Scale (UNS) scores, high baseline UNS, but not IVIg treatment, was associated with a reduction in narcolepsy symptoms. On time-to-event analysis, among patients with high baseline UNS scores, control patients achieved a UNS score narcolepsy symptoms were not significantly reduced by IVIg. However, in patients with high baseline symptoms, a subset of IVIg-treated patients achieved remission more rapidly than control patients. Commentary: A commentary on this article appears in this issue on page 363. Citation: Lecendreux M, Berthier J, Corny J, Bourdon O, Dossier C, Delclaux C. Intravenous immunoglobulin therapy in pediatric

  3. Cluster bomb ocular injuries

    Directory of Open Access Journals (Sweden)

    Ahmad M Mansour

    2012-01-01

    Full Text Available Purpose: To present the visual outcomes and ocular sequelae of victims of cluster bombs. Materials and Methods: This retrospective, multicenter case series of ocular injury due to cluster bombs was conducted for 3 years after the war in South Lebanon (July 2006. Data were gathered from the reports to the Information Management System for Mine Action. Results: There were 308 victims of clusters bombs; 36 individuals were killed, of which 2 received ocular lacerations and; 272 individuals were injured with 18 receiving ocular injury. These 18 surviving individuals were assessed by the authors. Ocular injury occurred in 6.5% (20/308 of cluster bomb victims. Trauma to multiple organs occurred in 12 of 18 cases (67% with ocular injury. Ocular findings included corneal or scleral lacerations (16 eyes, corneal foreign bodies (9 eyes, corneal decompensation (2 eyes, ruptured cataract (6 eyes, and intravitreal foreign bodies (10 eyes. The corneas of one patient had extreme attenuation of the endothelium. Conclusions: Ocular injury occurred in 6.5% of cluster bomb victims and 67% of the patients with ocular injury sustained trauma to multiple organs. Visual morbidity in civilians is an additional reason for a global ban on the use of cluster bombs.

  4. Angiodysplasia Occurring in Jejunal Diverticulosis

    OpenAIRE

    Edward A Jones; Hugh Chaun; Phillip Switzer; David J Clow; Ronald J Hancock

    1990-01-01

    The first case of angiodysplasia occurring in acquired jejunal diverticulosis is reported. The patient presented with occult gastrointestinal bleeding and chronic anemia, and was created successfully by resection of a 25 cm long segment of jejunum. Possible pathogenetic mechanisms for both angiodysplasia and jejunal diverticulosis are discussed.

  5. Cytogenetic aberrations in osteosarcomas. Nonrandom deletions, rings, and double-minute chromosomes.

    Science.gov (United States)

    Fletcher, J A; Gebhardt, M C; Kozakewich, H P

    1994-10-01

    Relatively few karyotypes have been reported from short-term cultures and/or direct harvests of osteosarcomas. We describe clonal aberrations in 17 high-grade osteosarcoma specimens and in one low-grade osteosarcoma. The high-grade osteosarcomas were karyotyped after direct harvest (four cases) or after short-term culture periods of osteosarcoma and two lung metastases, were from the same patient and shared a number of clonal aberrations. No consistent chromosome translocations were identified in the overall group of high-grade osteosarcomas, but potential nonrandom deletions involved 6q21-->qter, 9p21-->pter, chromosome 10, chromosome 13, 17p12-pter, and chromosome 20. Ring chromosomes were detected in three cases, and double-minute (dmin) chromosomes were detected in six. All high-grade osteosarcomas had numerous nonclonal chromosome aberrations superimposed on complex clonal events. The single low-grade osteosarcoma was characterized by a balanced, nonconstitutional, t(5;10) (p13;p14-15), together with an addition to the short arm of chromosome X. This is the first translocation reported in low-grade osteosarcoma, and the simplicity of the karyotype contrasts strikingly with those in the high-grade osteosarcomas.

  6. Assessing the impacts of nonrandom seed dispersal by multiple frugivore partners on plant recruitment.

    Science.gov (United States)

    Razafindratsima, Onja H; Dunham, Amy E

    2015-01-01

    Directed dispersal is defined as enhanced dispersal of seeds into suitable microhabitats, resulting in higher recruitment than if seeds were dispersed randomly. While this constitutes one of the main explanations for the adaptive value of frugivore-mediated seed dispersal, the generality of this advantage has received little study, particularly when multiple dispersers are involved. We used probability recruitment models of a long-lived rainforest tree in Madagascar to compare recruitment success under dispersal by multiple frugivores, no dispersal, and random dispersal. Models were parameterized using a three-year recruitment experiment and observational data of dispersal events by three frugivorous lemur species that commonly disperse its seeds. Frugivore-mediated seed dispersal was nonrandom with respect to canopy cover and increased modeled per-seed sapling recruitment fourfold compared to no dispersal. Seeds dispersed by one frugivore, Eulemur rubriventer, had higher modeled recruitment probability than seeds dispersed randomly. However, as a group, our models suggest that seeds dispersed by lemurs would have lower recruitment than if dispersal were random. Results demonstrate the importance of evaluating the contribution of multiple frugivores to plant recruitment for understanding plant population dynamics and the ecological and evolutionary significance of seed dispersal.

  7. Evidence for non-random sampling in randomised, controlled trials by Yuhji Saitoh.

    Science.gov (United States)

    Carlisle, J B; Loadsman, J A

    2017-01-01

    A large number of randomised trials authored by Yoshitaka Fujii have been retracted, in part as a consequence of a previous analysis finding a very low probability of random sampling. Dr Yuhji Saitoh co-authored 34 of those trials and he was corresponding author for eight of them. We found a number of additional randomised, controlled trials that included baseline data, with Saitoh as corresponding author, that Fujii did not co-author. We used Monte Carlo simulations to analyse the baseline data from 32 relevant trials in total as well as an outcome (muscle twitch recovery ratios) reported in several. We also compared a series of muscle twitch recovery graphs appearing in a number of Saitoh's publications. The baseline data in 14/32 randomised, controlled trials had p sampling. Combining the continuous and categorical probabilities of the 32 included trials, we found a very low likelihood of random sampling: p = 1.27 × 10(-8) (1 in 100,000,000). The high probability of non-random sampling and the repetition of lines in multiple graphs suggest that further scrutiny of Saitoh's work is warranted. © 2016 The Association of Anaesthetists of Great Britain and Ireland.

  8. A new non-randomized model for analysing sensitive questions with binary outcomes.

    Science.gov (United States)

    Tian, Guo-Liang; Yu, Jun-Wu; Tang, Man-Lai; Geng, Zhi

    2007-10-15

    We propose a new non-randomized model for assessing the association of two sensitive questions with binary outcomes. Under the new model, respondents only need to answer a non-sensitive question instead of the original two sensitive questions. As a result, it can protect a respondent's privacy, avoid the usage of any randomizing device, and be applied to both the face-to-face interview and mail questionnaire. We derive the constrained maximum likelihood estimates of the cell probabilities and the odds ratio for two binary variables associated with the sensitive questions via the EM algorithm. The corresponding standard error estimates are then obtained by bootstrap approach. A likelihood ratio test and a chi-squared test are developed for testing association between the two binary variables. We discuss the loss of information due to the introduction of the non-sensitive question, and the design of the co-operative parameters. Simulations are performed to evaluate the empirical type I error rates and powers for the two tests. In addition, a simulation is conducted to study the relationship between the probability of obtaining valid estimates and the sample size for any given cell probability vector. A real data set from an AIDS study is used to illustrate the proposed methodologies.

  9. DNA Repair Profiling Reveals Nonrandom Outcomes at Cas9-Mediated Breaks.

    Science.gov (United States)

    van Overbeek, Megan; Capurso, Daniel; Carter, Matthew M; Thompson, Matthew S; Frias, Elizabeth; Russ, Carsten; Reece-Hoyes, John S; Nye, Christopher; Gradia, Scott; Vidal, Bastien; Zheng, Jiashun; Hoffman, Gregory R; Fuller, Christopher K; May, Andrew P

    2016-08-18

    The repair outcomes at site-specific DNA double-strand breaks (DSBs) generated by the RNA-guided DNA endonuclease Cas9 determine how gene function is altered. Despite the widespread adoption of CRISPR-Cas9 technology to induce DSBs for genome engineering, the resulting repair products have not been examined in depth. Here, the DNA repair profiles of 223 sites in the human genome demonstrate that the pattern of DNA repair following Cas9 cutting at each site is nonrandom and consistent across experimental replicates, cell lines, and reagent delivery methods. Furthermore, the repair outcomes are determined by the protospacer sequence rather than genomic context, indicating that DNA repair profiling in cell lines can be used to anticipate repair outcomes in primary cells. Chemical inhibition of DNA-PK enabled dissection of the DNA repair profiles into contributions from c-NHEJ and MMEJ. Finally, this work elucidates a strategy for using "error-prone" DNA-repair machinery to generate precise edits.

  10. Impact of Integrated Services on HIV Testing: A Nonrandomized Trial among Kenyan Family Planning Clients.

    Science.gov (United States)

    Church, Kathryn; Warren, Charlotte E; Birdthistle, Isolde; Ploubidis, George B; Tomlin, Keith; Zhou, Weiwei; Kimani, James; Abuya, Timothy; Ndwiga, Charity; Sweeney, Sedona; Mayhew, Susannah H

    2017-06-01

    The impact of integrated reproductive health and HIV services on HIV testing and counseling (HTC) uptake was assessed among 882 Kenyan family planning clients using a nonrandomized cohort design within six intervention and six "comparison" facilities. The effect of integration on HTC goals (two tests over two years) was assessed using conditional logistic regression to test four "integration" exposures: a training and reorganization intervention; receipt of reproductive health and HIV services at recruitment; a functional measure of facility integration at recruitment; and a woman's cumulative exposure to functionally integrated care across different facilities over time. While recent receipt of HTC increased rapidly at intervention facilities, achievement of HTC goals was higher at comparison facilities. Only high cumulative exposure to integrated care over two years had a significant effect on HTC goals after adjustment (aOR 2.94, 95%CI 1.73-4.98), and programs should therefore make efforts to roll out integrated services to ensure repeated contact over time. © 2017 The Population Council, Inc.

  11. Chemical evolution of star clusters

    CERN Document Server

    van Loon, Jacco Th

    2009-01-01

    I discuss the chemical evolution of star clusters, with emphasis on old globular clusters, in relation to their formation histories. Globular clusters clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of globular clusters in dwarf galaxies has been suggested, present-day dwarf galaxies are not representative of the gravitational potential wells within which the globular clusters formed. Instead, a formation deep within the proto-Galaxy or within dark-matter minihaloes might be favoured. Not all globular clusters may have formed and evolved similarly. In particular, we may need to distinguish Galactic halo from Galactic bulge clusters.

  12. Radio observations of Planck clusters

    CERN Document Server

    Kale, Ruta

    2012-01-01

    Recently, a number of new galaxy clusters have been detected by the ESA-Planck satellite, the South Pole Telescope and the Atacama Cosmology Telescope using the Sunyaev-Zeldovich effect. Several of the newly detected clusters are massive, merging systems with disturbed morphology in the X-ray surface brightness. Diffuse radio sources in clusters, called giant radio halos and relics, are direct probes of cosmic rays and magnetic fields in the intra-cluster medium. These radio sources are found to occur mainly in massive merging clusters. Thus, the new SZ-discovered clusters are good candidates to search for new radio halos and relics. We have initiated radio observations of the clusters detected by Planck with the Giant Metrewave Radio Telescope. These observations have already led to the detection of a radio halo in PLCKG171.9-40.7, the first giant halo discovered in one of the new Planck clusters.

  13. Meaningful Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Calapristi, Augustin J.; Crow, Vernon L.; Hetzler, Elizabeth G.; Turner, Alan E.

    2004-05-26

    We present an approach to the disambiguation of cluster labels that capitalizes on the notion of semantic similarity to assign WordNet senses to cluster labels. The approach provides interesting insights on how document clustering can provide the basis for developing a novel approach to word sense disambiguation.

  14. Naturally Occurring Radioactive Materials (NORM)

    Energy Technology Data Exchange (ETDEWEB)

    Gray, P. [ed.

    1997-02-01

    This paper discusses the broad problems presented by Naturally Occuring Radioactive Materials (NORM). Technologically Enhanced naturally occuring radioactive material includes any radionuclides whose physical, chemical, radiological properties or radionuclide concentration have been altered from their natural state. With regard to NORM in particular, radioactive contamination is radioactive material in an undesired location. This is a concern in a range of industries: petroleum; uranium mining; phosphorus and phosphates; fertilizers; fossil fuels; forestry products; water treatment; metal mining and processing; geothermal energy. The author discusses in more detail the problem in the petroleum industry, including the isotopes of concern, the hazards they present, the contamination which they cause, ways to dispose of contaminated materials, and regulatory issues. He points out there are three key programs to reduce legal exposure and problems due to these contaminants: waste minimization; NORM assesment (surveys); NORM compliance (training).

  15. Allodynia in Cluster Headache.

    Science.gov (United States)

    Wilbrink, Leopoldine A; Louter, Mark A; Teernstra, Onno Pm; van Zwet, Erik W; Huygen, Frank Jpm; Haan, Joost; Ferrari, Michel D; Terwindt, Gisela M

    2017-03-04

    Cutaneous allodynia is an established marker for central sensitization in migraine. There is debate whether cutaneous allodynia may also occur in cluster headache, another episodic headache disorder. Here we examined the presence and severity of allodynia in a large well-defined nation-wide population of people with cluster headache.Using validated questionnaires we assessed, cross-sectionally, ictal allodynia and comorbid depression and migraine in the nation-wide "Leiden University Cluster headache neuro-Analysis" (LUCA) study. Participants with cluster headache were diagnosed according to the International Classification of Headache Disorders criteria. Multivariate regression models were used, with correction for demographic factors and cluster headache subtype (chronic vs. episodic; recent attacks cluster headache responded of whom 218/606 (36%) had allodynia during attacks. Female gender (OR 2.05, 95% CI 1.28-3.29), low age at onset (OR 0.98, 95% CI 0.96- 0.99), lifetime depression (OR 1.63; 95% CI 1.06-2.50), comorbid migraine (OR 1.96; 95% CI 1.02-3.79), and having recent attacks (OR 1.80; 95% CI 1.13-2.86), but not duration of attacks and chronic cluster headache, were independent risk factors for allodynia.The high prevalence of cutaneous allodynia with similar risk factors for allodynia as found for migraine suggests that central sensitization, like in migraine, also occurs in cluster headache. In clinical practice, awareness that people with cluster headache may suffer from allodynia can in the future be an important feature in treatment options.

  16. Cluster headaches.

    Science.gov (United States)

    Ryan, R E; Ryan, R E

    1989-12-01

    The patient with cluster headaches will be afflicted with the most severe type of pain that one will encounter. If the physician can do something to help this patient either by symptomatic or, more importantly, prophylactic treatment, he or she will have a most thankful patient. This type of headache is seen most frequently in men, and occurs in a cyclic manner. During an acute cycle, the patient will experience a daily type of pain that may occur many times per day. The pain is usually unilateral and may be accompanied by unilateral lacrimation, conjunctivitis, and clear rhinorrhea. Prednisone is the first treatment we employ. Patients are seen for follow-up approximately twice a week, and their medication is lowered in an appropriate manner, depending on their response to the treatment. Regulation of dosage has to be individualized, and when one reaches the lower dose such as 5 to 10 mg per day, the drug may have to be tapered more slowly, or even maintained at that level for a period of time to prevent further recurrence of symptoms. We frequently will use an intravenous histamine desensitization technique to prevent further attacks. We will give the patient an ergotamine preparation to use for symptomatic relief. As these patients often have headaches during the middle of the night, we will place the patient on a 2-mg ergotamine preparation to take prior to going to bed in the evening. This often works in a prophylactic nature, and prevents the nighttime occurrence of a headache. We believe that following these principles to make the accurate diagnosis and institute the proper therapy will help the practicing otolaryngologist recognize and treat patients suffering from this severe pain.

  17. Non-random assembly of bacterioplankton communities in the subtropical North Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Alexander eEiler

    2011-07-01

    Full Text Available The exploration of bacterial diversity in the global ocean has revealed new taxa and previously unrecognized metabolic potential; however, our understanding of what regulates this diversity is limited. Using terminal restriction fragment length polymorphism (T-RFLP data of bacterial small-subunit ribosomal RNA genes we show that, independent of depth and time, a large fraction of bacterioplankton co-occurrence patterns are non-random in the oligotrophic North Pacific subtropical gyre (NPSG. Pair-wise correlations of all identified operational taxonomic units (OTUs revealed a high degree of significance, with 6.6% of the pair-wise co-occurrences being negatively correlated and 20.7% of them being positive. The most abundant OTUs, putatively identified as Prochlorococcus, SAR11 and SAR116 bacteria, were among the most correlated OTUs. As expected, bacterial community composition lacked statistically significant patterns of seasonality in the mostly stratified water column except in a few depth horizons of the sunlit surface waters, with higher frequency variations in community structure apparently related to populations associated with the deep chlorophyll maximum. Communities were structured vertically, with a succession from euphotic, mesopelagic, and bathylopelagic populations. Permutation based statistical analyses of T-RFLP data and their corresponding metadata revealed a broad range of putative environmental drivers controlling bacterioplankton community composition in the NPSG, including concentrations of inorganic nutrients and phytoplankton pigment. Together our results suggest that deterministic forces, such as environmental filtering and interactions among taxa, determine bacterioplankton community patterns, and consequently affect ecosystem functions in the NPSG.

  18. Outcome of Percutaneous Release of Tennis Elbow: A Non-Randomized Controlled Trial Study

    Science.gov (United States)

    Khatri, Kishor; Kharel, Krishna; Byanjankar, Subin; Shrestha, Rahul; Sharma, Jay R; Vaishya, Raju; Agarwal, Amit kumar; Vijay, Vipul

    2017-01-01

    Background Tennis elbow is a common disorder of the upper extremity. It can be treated conservatively in the majority of patients, but some resistant cases eventually can be treated by percutaneous release with good functional outcome. Materials and methods This non-randomized control trial was conducted at the Department of Orthopaedics Surgery in a tertiary care hospital from July 2015 to June 2016 on 50 patients who underwent percutaneous release of the common extensor origin using an 18 gauge hypodermic needle. These patients did not respond to conservative treatment including rest, nonsteroidal anti-inflammatory drugs (NSAIDS) and local steroid injections. The outcome was graded as Excellent, Good, Fair, and Poor. Results Fifty patients (50 elbows) were included in the study. Thirty-two patients were female (64%), and 18 were male (36%). The right side was affected in 37 patients (74%) and left side in 13 (26%). The time taken to achieve a completely pain-free elbow ranged from one day to two months (average of 26.2 days). Those who did not achieve a pain-free elbow had a residual pain of 1.5 to six on the visual analogue scale (VAS) (average 2.32). Excellent outcome was noticed in 24 patients (48%); Good result in eight patients (36% ); Fair in four patients (eight percent) and Poor in four patients (eight percent). Conclusion Tennis elbow probably results from the degenerative tear of the common extensor origin, and a percutaneous tenotomy using an 18 gauge hypodermic needle is a simple, safe, patient-friendly, efficient, and easily reproducible method of treating tennis elbow in those who are resistant to conservative treatment, and it can be done as an outpatient procedure. PMID:28168130

  19. Cortical microtubule arrays are initiated from a nonrandom prepattern driven by atypical microtubule initiation.

    Science.gov (United States)

    Lindeboom, Jelmer J; Lioutas, Antonios; Deinum, Eva E; Tindemans, Simon H; Ehrhardt, David W; Emons, Anne Mie C; Vos, Jan W; Mulder, Bela M

    2013-03-01

    The ordered arrangement of cortical microtubules in growing plant cells is essential for anisotropic cell expansion and, hence, for plant morphogenesis. These arrays are dismantled when the microtubule cytoskeleton is rearranged during mitosis and reassembled following completion of cytokinesis. The reassembly of the cortical array has often been considered as initiating from a state of randomness, from which order arises at least partly through self-organizing mechanisms. However, some studies have shown evidence for ordering at early stages of array assembly. To investigate how cortical arrays are initiated in higher plant cells, we performed live-cell imaging studies of cortical array assembly in tobacco (Nicotiana tabacum) Bright Yellow-2 cells after cytokinesis and drug-induced disassembly. We found that cortical arrays in both cases did not initiate randomly but with a significant overrepresentation of microtubules at diagonal angles with respect to the cell axis, which coincides with the predominant orientation of the microtubules before their disappearance from the cell cortex in preprophase. In Arabidopsis (Arabidopsis thaliana) root cells, recovery from drug-induced disassembly was also nonrandom and correlated with the organization of the previous array, although no diagonal bias was observed in these cells. Surprisingly, during initiation, only about one-half of the new microtubules were nucleated from locations marked by green fluorescent protein-γ-tubulin complex protein2-tagged γ-nucleation complexes (γ-tubulin ring complex), therefore indicating that a large proportion of early polymers was initiated by a noncanonical mechanism not involving γ-tubulin ring complex. Simulation studies indicate that the high rate of noncanonical initiation of new microtubules has the potential to accelerate the rate of array repopulation.

  20. Cluster Chemistry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Cansisting of eight scientists from the State Key Laboratory of Physical Chemistry of Solid Surfaces and Xiamen University, this creative research group is devoted to the research of cluster chemistry and creation of nanomaterials.After three-year hard work, the group scored a series of encouraging progresses in synthesis of clusters with special structures, including novel fullerenes, fullerene-like metal cluster compounds as well as other related nanomaterials, and their properties study.

  1. Cluster headache

    Directory of Open Access Journals (Sweden)

    Ducros Anne

    2008-07-01

    Full Text Available Abstract Cluster headache (CH is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye. It affects young adults, predominantly males. Prevalence is estimated at 0.5–1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name in bouts that can occur during specific months of the year. Alcohol is the only dietary trigger of CH, strong odors (mainly solvents and cigarette smoke and napping may also trigger CH attacks. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH is associated with trigeminovascular activation and neuroendocrine and vegetative disturbances, however, the precise cautive mechanisms remain unknown. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments and to reduce the number of daily attacks (prophylactic treatments. Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the

  2. Sexuality Generates Diversity in the Aflatoxin Gene Cluster: Evidence on a Global Scale

    Science.gov (United States)

    Moore, Geromy G.; Elliott, Jacalyn L.; Singh, Rakhi; Horn, Bruce W.; Dorner, Joe W.; Stone, Eric A.; Chulze, Sofia N.; Barros, German G.; Naik, Manjunath K.; Wright, Graeme C.; Hell, Kerstin; Carbone, Ignazio

    2013-01-01

    Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B1 being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs). We examined natural genetic variation in 758 isolates of A. flavus, A. parasiticus and A. minisclerotigenes sampled from single peanut fields in the United States (Georgia), Africa (Benin), Argentina (Córdoba), Australia (Queensland) and India (Karnataka). Analysis of DNA sequence variation across multiple intergenic regions in the aflatoxin gene clusters of A. flavus, A. parasiticus and A. minisclerotigenes revealed significant linkage disequilibrium (LD) organized into distinct blocks that are conserved across different localities, suggesting that genetic recombination is nonrandom and a global occurrence. To assess the contributions of asexual and sexual reproduction to fixation and maintenance of toxin chemotype diversity in populations from each locality/species, we tested the null hypothesis of an equal number of MAT1-1 and MAT1-2 mating-type individuals, which is indicative of a sexually recombining population. All samples were clone-corrected using multi-locus sequence typing which associates closely with VCG. For both A. flavus and A. parasiticus, when the proportions of MAT1-1 and MAT1-2 were significantly different, there was more extensive LD in the aflatoxin cluster and populations were fixed for specific toxin chemotype classes, either the non-aflatoxigenic class in A. flavus or the B1-dominant and G1-dominant classes in A. parasiticus. A mating type ratio close to 1∶1 in A. flavus, A. parasiticus and A. minisclerotigenes was associated with higher recombination rates in the aflatoxin cluster and less pronounced chemotype differences in populations. This work shows that the reproductive nature of the population (more

  3. Sexuality generates diversity in the aflatoxin gene cluster: evidence on a global scale.

    Directory of Open Access Journals (Sweden)

    Geromy G Moore

    Full Text Available Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B₁ being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs. We examined natural genetic variation in 758 isolates of A. flavus, A. parasiticus and A. minisclerotigenes sampled from single peanut fields in the United States (Georgia, Africa (Benin, Argentina (Córdoba, Australia (Queensland and India (Karnataka. Analysis of DNA sequence variation across multiple intergenic regions in the aflatoxin gene clusters of A. flavus, A. parasiticus and A. minisclerotigenes revealed significant linkage disequilibrium (LD organized into distinct blocks that are conserved across different localities, suggesting that genetic recombination is nonrandom and a global occurrence. To assess the contributions of asexual and sexual reproduction to fixation and maintenance of toxin chemotype diversity in populations from each locality/species, we tested the null hypothesis of an equal number of MAT1-1 and MAT1-2 mating-type individuals, which is indicative of a sexually recombining population. All samples were clone-corrected using multi-locus sequence typing which associates closely with VCG. For both A. flavus and A. parasiticus, when the proportions of MAT1-1 and MAT1-2 were significantly different, there was more extensive LD in the aflatoxin cluster and populations were fixed for specific toxin chemotype classes, either the non-aflatoxigenic class in A. flavus or the B₁-dominant and G₁-dominant classes in A. parasiticus. A mating type ratio close to 1∶1 in A. flavus, A. parasiticus and A. minisclerotigenes was associated with higher recombination rates in the aflatoxin cluster and less pronounced chemotype differences in populations. This work shows that the reproductive nature of

  4. Variation in verb cluster interruption

    NARCIS (Netherlands)

    Hendriks, Lotte

    2014-01-01

    Except for finite verbs in main clauses, verbs in Standard Dutch cluster together in a clause-final position. In certain Dutch dialects, non-verbal material can occur within this verb cluster (Verhasselt 1961; Koelmans 1965, among many others). These dialects vary with respect to which types of

  5. An open-label, non-randomized comparison of venlafaxine and gabapentin as monotherapy or adjuvant therapy in the management of neuropathic pain in patients with peripheral neuropathy

    Directory of Open Access Journals (Sweden)

    William Eardley

    2010-04-01

    Full Text Available William Eardley, Cory TothDepartment of Clinical Neurosciences and the University of Calgary, Calgary, AB, CanadaAbstract: Although many therapies are used in the management of neuropathic pain (NeP due to polyneuropathy (PN, few comparison studies exist. We performed a prospective, non-randomized, unblended, efficacy comparison of the serotonin-norepinephrine reuptake inhibitor venlafaxine, as either monotherapy or adjuvant therapy, with a first-line medication for NeP, gabapentin, in patients with PN-related NeP. VAS pain scores were assessed after 3 and 6 months in intervention groups and in a cohort of patients receiving no pharmacotherapy. In a total of 223 patients, we analyzed pain quantity and quality (visual analogue scale [VAS] score, Brief Pain Inventory [BPI], quality of life and health status measures [EuroQol 5 Domains, EQ-5D], Medical Outcomes Sleep Study Scale [MOSSS], Hospital Anxiety and Depression Scale [HADS] and Short Form 36 Health Survey [SF-36] after 6 months of therapy. Significant improvements in VAS pain scores occurred for all treatment groups after 6 months. Improvements in aspects of daily life and anxiety were identified in all treatment groups. Our data suggest that monotherapy or adjuvant therapy with venlafaxine is comparable to gabapentin for NeP management. We advocate for head-to-head, randomized, double-blinded studies of current NeP therapies.Keywords: peripheral neuropathy, neuropathic pain, pharmacotherapy, venlafaxine, gabapentin

  6. Clustered regression with unknown clusters

    CERN Document Server

    Barman, Kishor

    2011-01-01

    We consider a collection of prediction experiments, which are clustered in the sense that groups of experiments ex- hibit similar relationship between the predictor and response variables. The experiment clusters as well as the regres- sion relationships are unknown. The regression relation- ships define the experiment clusters, and in general, the predictor and response variables may not exhibit any clus- tering. We call this prediction problem clustered regres- sion with unknown clusters (CRUC) and in this paper we focus on linear regression. We study and compare several methods for CRUC, demonstrate their applicability to the Yahoo Learning-to-rank Challenge (YLRC) dataset, and in- vestigate an associated mathematical model. CRUC is at the crossroads of many prior works and we study several prediction algorithms with diverse origins: an adaptation of the expectation-maximization algorithm, an approach in- spired by K-means clustering, the singular value threshold- ing approach to matrix rank minimization u...

  7. When Yawning Occurs in Elephants

    Science.gov (United States)

    Rossman, Zoë T.; Hart, Benjamin L.; Greco, Brian J.; Young, Debbie; Padfield, Clare; Weidner, Lisa; Gates, Jennifer; Hart, Lynette A.

    2017-01-01

    Yawning is a widely recognized behavior in mammalian species. One would expect that elephants yawn, although to our knowledge, no one has reported observations of yawning in any species of elephant. After confirming a behavioral pattern matching the criteria of yawning in two Asian elephants (Elephas maximus) in a zoological setting, this study was pursued with nine captive African elephants (Loxodonta africana) at a private reserve in the Western Cape, South Africa, the Knysna Elephant Park. Observations were made in June–September and in December. In the daytime, handlers managed seven of the elephants for guided interactions with visitors. At night, all elephants were maintained in a large enclosure with six having limited outdoor access. With infrared illumination, the elephants were continuously recorded by video cameras. During the nights, the elephants typically had 1–3 recumbent sleeping/resting bouts, each lasting 1–2 h. Yawning was a regular occurrence upon arousal from a recumbency, especially in the final recumbency of the night. Yawning was significantly more frequent in some elephants. Yawning was rare during the daytime and during periods of standing around in the enclosure at night. In six occurrences of likely contagious yawning, one elephant yawned upon seeing another elephant yawning upon arousal from a final recumbency; we recorded the sex and age category of the participants. The generality of yawning in both African and Asian elephants in other environments was documented in video recordings from 39 zoological facilities. In summary, the study provides evidence that yawning does occur in both African and Asian elephants, and in African elephants, yawning was particularly associated with arousal from nighttime recumbencies. PMID:28293560

  8. Subspace clustering through attribute clustering

    Institute of Scientific and Technical Information of China (English)

    Kun NIU; Shubo ZHANG; Junliang CHEN

    2008-01-01

    Many recently proposed subspace clustering methods suffer from two severe problems. First, the algorithms typically scale exponentially with the data dimensionality or the subspace dimensionality of clusters. Second, the clustering results are often sensitive to input parameters. In this paper, a fast algorithm of subspace clustering using attribute clustering is proposed to over-come these limitations. This algorithm first filters out redundant attributes by computing the Gini coefficient. To evaluate the correlation of every two non-redundant attributes, the relation matrix of non-redundant attributes is constructed based on the relation function of two dimensional united Gini coefficients. After applying an overlapping clustering algorithm on the relation matrix, the candidate of all interesting subspaces is achieved. Finally, all subspace clusters can be derived by clustering on interesting subspaces. Experiments on both synthesis and real datasets show that the new algorithm not only achieves a significant gain of runtime and quality to find subspace clusters, but also is insensitive to input parameters.

  9. Multidisciplinary intervention reducing readmissions in medical inpatients: a prospective, non-randomized study

    Directory of Open Access Journals (Sweden)

    Torisson G

    2013-09-01

    Full Text Available Gustav Torisson,1 Lennart Minthon,1 Lars Stavenow,2 Elisabet Londos1 1Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, 2Department of Internal Medicine, Skåne University Hospital, Malmö, Sweden Background: The purpose of this study was to examine whether a multidisciplinary intervention targeting drug-related problems, cognitive impairment, and discharge miscommunication could reduce readmissions in a general hospital population. Methods: This prospective, non-randomized intervention study was carried out at the department of general internal medicine at a tertiary university hospital. Two hundred medical inpatients living in the community and aged over 60 years were included. Ninety-nine patients received interventions and 101 received standard care. Control/intervention allocation was determined by geographic selection. Interventions consisted of a comprehensive medication review, improved discharge planning, post-discharge telephone follow-up, and liaison with the patient's general practitioner. The main outcome measures recorded were readmissions and hospital nights 12 months after discharge. Separate analyses were made for 12-month survivors and from an intention-to-treat perspective. Comparative analyses were made between groups as well as within groups over time. Results: After 12 months, survivors in the control group had 125 readmissions in total, compared with 58 in the intervention group (Mann–Whitney U test, P = 0.02. For hospital nights, the numbers were 1,228 and 492, respectively (P = 0.009. Yearly admissions had increased from the previous year in the control group from 77 to 125 (Wilcoxon signed-rank test, P = 0.002 and decreased from 75 to 58 in the intervention group (P = 0.25. From the intention-to-treat perspective, the same general pattern was observed but was not significant (1,827 versus 1,008 hospital nights, Mann–Whitney test, P = 0.054. Conclusion: A multidisciplinary approach

  10. Cluster editing

    DEFF Research Database (Denmark)

    Böcker, S.; Baumbach, Jan

    2013-01-01

    . The problem has been the inspiration for numerous algorithms in bioinformatics, aiming at clustering entities such as genes, proteins, phenotypes, or patients. In this paper, we review exact and heuristic methods that have been proposed for the Cluster Editing problem, and also applications......The Cluster Editing problem asks to transform a graph into a disjoint union of cliques using a minimum number of edge modifications. Although the problem has been proven NP-complete several times, it has nevertheless attracted much research both from the theoretical and the applied side...

  11. Weighted Clustering

    CERN Document Server

    Ackerman, Margareta; Branzei, Simina; Loker, David

    2011-01-01

    In this paper we investigate clustering in the weighted setting, in which every data point is assigned a real valued weight. We conduct a theoretical analysis on the influence of weighted data on standard clustering algorithms in each of the partitional and hierarchical settings, characterising the precise conditions under which such algorithms react to weights, and classifying clustering methods into three broad categories: weight-responsive, weight-considering, and weight-robust. Our analysis raises several interesting questions and can be directly mapped to the classical unweighted setting.

  12. Cluster analysis

    CERN Document Server

    Everitt, Brian S; Leese, Morven; Stahl, Daniel

    2011-01-01

    Cluster analysis comprises a range of methods for classifying multivariate data into subgroups. By organizing multivariate data into such subgroups, clustering can help reveal the characteristics of any structure or patterns present. These techniques have proven useful in a wide range of areas such as medicine, psychology, market research and bioinformatics.This fifth edition of the highly successful Cluster Analysis includes coverage of the latest developments in the field and a new chapter dealing with finite mixture models for structured data.Real life examples are used throughout to demons

  13. Discovery of Non-random Spatial Distribution of Impacts in the Stardust Cometary Collector

    Energy Technology Data Exchange (ETDEWEB)

    Westphal, A J; Bastien, R K; Borg, J; Bridges, J; Brownlee, D E; Burchell, M J; Cheng, A F; Clark, B C; Djouadi, Z; Floss, C; Franchi, I; Gainsforth, Z; Graham, G; Green, S F; Heck, P R; Horanyi, M; Hoppe, P; Horz, F P; Huth, J; Kearsley, A; Leroux, H; Marhas, K; Nakamura-Messenger, K; Sandford, S A; See, T H; Stadermann, F J; Teslich, N E; Tsitrin, S; Warren, J L; Wozniakiewicz, P J; Zolensky, M E

    2007-04-06

    We report the discovery that impacts in the Stardust cometary collector are not distributed randomly in the collecting media, but appear to be clustered on scales smaller than {approx} 10 cm. We also report the discovery of at least two populations of oblique tracks. We evaluated several hypotheses that could explain the observations. No hypothesis was consistent with all the observations, but the preponderance of evidence points toward at least one impact on the central Whipple shield of the spacecraft as the origin of both clustering and low-angle oblique tracks. High-angle oblique tracks unambiguously originate from a non-cometary impact on the spacecraft bus just forward of the collector.

  14. Fuzzy Clustering

    DEFF Research Database (Denmark)

    Berks, G.; Keyserlingk, Diedrich Graf von; Jantzen, Jan

    2000-01-01

    A symptom is a condition indicating the presence of a disease, especially, when regarded as an aid in diagnosis.Symptoms are the smallest units indicating the existence of a disease. A syndrome on the other hand is an aggregate, set or cluster of concurrent symptoms which together indicate...... and clustering are the basic concerns in medicine. Classification depends on definitions of the classes and their required degree of participant of the elements in the cases' symptoms. In medicine imprecise conditions are the rule and therefore fuzzy methods are much more suitable than crisp ones. Fuzzy c......-mean clustering is an easy and well improved tool, which has been applied in many medical fields. We used c-mean fuzzy clustering after feature extraction from an aphasia database. Factor analysis was applied on a correlation matrix of 26 symptoms of language disorders and led to five factors. The factors...

  15. Intracorneal Rings (INTACS SK) Might be Beneficial in Keratoconus; A Prospective Nonrandomized Study.

    Science.gov (United States)

    A Ibrahim, Tarek; Elmor, Osama

    2013-01-01

    In order to determine the effect of intracorneal rings (Intacs SK), when implanted in keratoconic patients, on corneal curvature, Uncorrected Visual Acuity (UCVA), Best Corrected Visual Acuity (BCVA) and on the progression of the cone through three years follow-up period. In this prospective nonrandomized study 114 eyes of 71 keratoconic patients (38 females and 33 males) were implanted with Intacs SK. Incisions were always made in the steep meridian. UCVA, BCVA, Corneal Topography (TMS) were measured pre and postoperatively and at intervals of 1, 3, 6 & 12 months then yearly for 3 consecutive years. Preoperative mean k-reading was 52.53 and 48.18, 49.56, 49.17, 48.51, 48.15 & 48.01 at 1, 3, 6, 12, 24 & 36 months postoperatively (P‹0.01). In terms of UCVA, 15.64% of patients gained more than 3 lines and 69.73% gained 1-3 lines with a total of 85.37% of patients gaining lines compared to their preoperative UCVA (P‹0.01) while 14.63% of cases did not gain any lines at 1 month postoperative. At three months postoperatively, 12.64% gained more than 3 lines, 71.15% gained 1-3 lines with a total of 83.79% while 16.21% did not gain any lines. Three years postoperative 11.82% of cases gained more than 3 lines, 73.23% gained 1-3 lines with a total of 85.05% while 14.95% did not gain any lines (P‹0.01). With regard to BCVA, 19.73% gained more than 3 lines, 68.26% gained 1-3 lines with a total of 87.99% of cases gaining lines compared to their preoperative BCVA (P‹0.01) while 12.01% did not gained any lines at 1 month postoperative. At three months postoperatively, 14.96% gained more than 3 lines, 70.19% gained 1-3 lines with a total of 85.15% while 14.85% did not gain any lines. Three years postoperative, 12.17% gained more than 3 lines, 71.78% gained 1-3 lines with a total of 83.95% (P‹0.01) while 16.05% did not gain any lines. No eyes lost any lines as it pertained to UCVA & BCVA. Despite the fluctuation of k-readings, UCVA and BCVA in the first 3 months, which

  16. Fission of Multiply Charged Alkali Clusters

    Science.gov (United States)

    Barnett, Robert N.; Yannouleas, Constantine; Landman, Uzi

    2001-03-01

    We use ab-initio molecular dynamics simulations to investigate the fission of multiply charged pure and mixed alkali clusters. Positive (+2 to +4) clusters of up to 30 atoms are considered. The clusters are initially equilibrated with a charge of +1 or +2 (depending on size) and at temperatures of 150 to 800 K. subsequently the clusters are further ionized and their evolution is followed. For doubly charged clusters binary fission occurs, while higher charged clusters fission through ternary or quaternary channels. The most common occurrence is the emission of a singly charged 3-atom cluster, which may occur repeatedly until the remaining cluster is stable. The dynamics of the fission process is discussed, and the results are compared with experiments and with the predictions of the liquid-drop and shell-corrected jellium models.

  17. A meta-analysis of nonrandomized effectiveness studies on outpatient cognitive behavioral therapy for adult anxiety disorders.

    Science.gov (United States)

    Hans, Eva; Hiller, Wolfgang

    2013-12-01

    The primary aim of this study was to assess the overall effectiveness of individual and group outpatient cognitive behavioral therapy (CBT) for adults with a primary anxiety disorder in routine clinical practice. We conducted a random effects meta-analysis of 71 nonrandomized effectiveness studies on outpatient individual and group CBT for adult anxiety disorders. Standardized mean gain effect sizes pre- to posttreatment, and posttreatment to follow-up are reported for disorder-specific symptoms, depression, and general anxiety. The mean dropout from CBT is reported. Outpatient CBT was effective in reducing disorder-specific symptoms in completer (d=0.90-1.91) and intention-to-treat samples (d=0.67-1.45). Moderate to large (d=0.54-1.09) and small to large effect sizes (d=0.42-0.97) were found for depressive and general anxiety symptoms posttreatment. Across all anxiety disorders, the weighted mean dropout rate was 15.06%. Posttreatment gains for disorder-specific anxiety were maintained 12months after completion of therapy. CBT for adult anxiety disorders is very effective and widely accepted in routine practice settings. However, the methodological and reporting quality of nonrandomized effectiveness studies must be improved. © 2013.

  18. Discovering non-random segregation of sister chromatids: The naïve treatment of a premature discovery

    Directory of Open Access Journals (Sweden)

    Karl G. Lark

    2013-02-01

    Full Text Available The discovery of non-random chromosome segregation is discussed from the perspective of what was known in1965 and1966. The distinction between daughter, parent or grandparent strands of DNA was developed in a bacterial system and led to the discovery that multiple copies of DNA elements of bacteria are not distributed randomly with respect to the age of the template strand. Experiments with higher eukaryotic cells demonstrated that during mitosis Mendel’s laws were violated; and the initial serendipitous choice of eukaryotic cell system led to the striking example of non-random segregation of parent and grand-parent DNA template strands in primary cultures of cells derived from mouse embryos. Attempts to extrapolate these findings to established TC lines demonstrated that the property could be lost. Experiments using plant root tips demonstrated that the phenomenon exists in plants and that it was, at some level, under genetic control. Despite publication in major journals and symposia (Lark et al. (1966a; Lark (1967a; 1967b; 1969, 1969a; 1969b the potential implications of these findings were ignored for several decades. Here we explore possible reasons for the pre-maturity (Stent, 1972 of this discovery.

  19. Nonrandom distribution of vector ticks (Dermacentor variabilis infected by Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    Heidi K Goethert

    2009-02-01

    Full Text Available The island of Martha's Vineyard, Massachusetts, is the site of a sustained outbreak of tularemia due to Francisella tularensis tularensis. Dog ticks, Dermacentor variabilis, appear to be critical in the perpetuation of the agent there. Tularemia has long been characterized as an agent of natural focality, stably persisting in characteristic sites of transmission, but this suggestion has never been rigorously tested. Accordingly, we sought to identify a natural focus of transmission of the agent of tularemia by mapping the distribution of PCR-positive ticks. From 2004 to 2007, questing D. variabilis were collected from 85 individual waypoints along a 1.5 km transect in a field site on Martha's Vineyard. The positions of PCR-positive ticks were then mapped using ArcGIS. Cluster analysis identified an area approximately 290 meters in diameter, 9 waypoints, that was significantly more likely to yield PCR-positive ticks (relative risk 3.3, P = 0.001 than the rest of the field site. Genotyping of F. tularensis using variable number tandem repeat (VNTR analysis on PCR-positive ticks yielded 13 different haplotypes, the vast majority of which was one dominant haplotype. Positive ticks collected in the cluster were 3.4 times (relative risk = 3.4, P<0.0001 more likely to have an uncommon haplotype than those collected elsewhere from the transect. We conclude that we have identified a microfocus where the agent of tularemia stably perpetuates and that this area is where genetic diversity is generated.

  20. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    .g. sustainability or quality of life. The purpose of this paper is to explore how and to what extent public sector interventions that aim at forcing cluster development in industries can support sustainable development as defined in the Brundtland tradition and more recently elaborated in such concepts as eco......, Portugal and New Zealand have adopted the concept. Public sector interventions that aim to support cluster development in industries most often focus upon economic policy goals such as enhanced employment and improved productivity, but rarely emphasise broader societal policy goals relating to e...... to the automotive sector in Wales. Specifically, the paper evaluates the "Accelerates" programme initiated by the Welsh Development Agency and elaborates on how and to what extent the Accelerate programme supports the development of a sustainable automotive industry cluster. The Accelerate programme was set up...

  1. Active matter clusters at interfaces.

    Directory of Open Access Journals (Sweden)

    Katherine eCopenhagen

    2016-03-01

    Full Text Available Collective and directed motility or swarming is an emergent phenomenon displayed by many self-organized assemblies of active biological matter such as clusters of embryonic cells during tissue development, cancerous cells during tumor formation and metastasis, colonies of bacteria in a biofilm, or even flocks of birds and schools of fish at the macro-scale. Such clusters typically encounter very heterogeneous environments. What happens when a cluster encounters an interface between two different environments has implications for its function and fate. Here we study this problem by using a mathematical model of a cluster that treats it as a single cohesive unit that moves in two dimensions by exerting a force/torque per unit area whose magnitude depends on the nature of the local environment. We find that low speed (overdamped clusters encountering an interface with a moderate difference in properties can lead to refraction or even total internal reflection of the cluster. For large speeds (underdamped, where inertia dominates, the clusters show more complex behaviors crossing the interface multiple times and deviating from the predictable refraction and reflection for the low velocity clusters. We then present an extreme limit of the model in the absence of rotational damping where clusters can become stuck spiraling along the interface or move in large circular trajectories after leaving the interface. Our results show a wide range of behaviors that occur when collectively moving active biological matter moves across interfaces and these insights can be used to control motion by patterning environments.

  2. Active matter clusters at interfaces.

    Science.gov (United States)

    Copenhagen, Katherine; Gopinathan, Ajay

    2016-03-01

    Collective and directed motility or swarming is an emergent phenomenon displayed by many self-organized assemblies of active biological matter such as clusters of embryonic cells during tissue development, cancerous cells during tumor formation and metastasis, colonies of bacteria in a biofilm, or even flocks of birds and schools of fish at the macro-scale. Such clusters typically encounter very heterogeneous environments. What happens when a cluster encounters an interface between two different environments has implications for its function and fate. Here we study this problem by using a mathematical model of a cluster that treats it as a single cohesive unit that moves in two dimensions by exerting a force/torque per unit area whose magnitude depends on the nature of the local environment. We find that low speed (overdamped) clusters encountering an interface with a moderate difference in properties can lead to refraction or even total internal reflection of the cluster. For large speeds (underdamped), where inertia dominates, the clusters show more complex behaviors crossing the interface multiple times and deviating from the predictable refraction and reflection for the low velocity clusters. We then present an extreme limit of the model in the absence of rotational damping where clusters can become stuck spiraling along the interface or move in large circular trajectories after leaving the interface. Our results show a wide range of behaviors that occur when collectively moving active biological matter moves across interfaces and these insights can be used to control motion by patterning environments.

  3. Two-stage revision surgery with preformed spacers and cementless implants for septic hip arthritis: a prospective, non-randomized cohort study

    Directory of Open Access Journals (Sweden)

    Logoluso Nicola

    2011-05-01

    Full Text Available Abstract Background Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol. Methods Nineteen patients (20 hips were enrolled in this prospective, non-randomized cohort study between 2000 and 2008. The first stage comprised femoral head resection, debridement, and insertion of a preformed, commercially available, antibiotic-loaded cement hip spacer. After eradication of infection, a cementless total hip arthroplasty was implanted in the second stage. Patients were assessed for infection recurrence, pain (visual analog scale [VAS] and hip joint function (Harris Hip score. Results The mean time between first diagnosis of infection and revision surgery was 5.8 ± 9.0 months; the average duration of follow up was 56.6 (range, 24 - 104 months; all 20 hips were successfully converted to prosthesis an average 22 ± 5.1 weeks after spacer implantation. Reinfection after total hip joint replacement occurred in 1 patient. The mean VAS pain score improved from 48 (range, 35 - 84 pre-operatively to 18 (range, 0 - 38 prior to spacer removal and to 8 (range, 0 - 15 at the last follow-up assessment after prosthesis implantation. The average Harris Hip score improved from 27.5 before surgery to 61.8 between the two stages to 92.3 at the final follow-up assessment. Conclusions Satisfactory outcomes can be obtained with two-stage revision hip arthroplasty using preformed spacers and cementless implants for prosthetic hip joint infections of various etiologies.

  4. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    The cluster theory attributed to Michael Porter has significantly influenced industrial policies in countries across Europe and North America since the beginning of the 1990s. Institutions such as the EU, OECD and the World Bank and governments in countries such as the UK, France, The Netherlands...

  5. Retroviral integration process in the human genome: is it really non-random? A new statistical approach.

    Directory of Open Access Journals (Sweden)

    Alessandro Ambrosi

    Full Text Available Retroviral vectors are widely used in gene therapy to introduce therapeutic genes into patients' cells, since, once delivered to the nucleus, the genes of interest are stably inserted (integrated into the target cell genome. There is now compelling evidence that integration of retroviral vectors follows non-random patterns in mammalian genome, with a preference for active genes and regulatory regions. In particular, Moloney Leukemia Virus (MLV-derived vectors show a tendency to integrate in the proximity of the transcription start site (TSS of genes, occasionally resulting in the deregulation of gene expression and, where proto-oncogenes are targeted, in tumor initiation. This has drawn the attention of the scientific community to the molecular determinants of the retroviral integration process as well as to statistical methods to evaluate the genome-wide distribution of integration sites. In recent approaches, the observed distribution of MLV integration distances (IDs from the TSS of the nearest gene is assumed to be non-random by empirical comparison with a random distribution generated by computational simulation procedures. To provide a statistical procedure to test the randomness of the retroviral insertion pattern, we propose a probability model (Beta distribution based on IDs between two consecutive genes. We apply the procedure to a set of 595 unique MLV insertion sites retrieved from human hematopoietic stem/progenitor cells. The statistical goodness of fit test shows the suitability of this distribution to the observed data. Our statistical analysis confirms the preference of MLV-based vectors to integrate in promoter-proximal regions.

  6. Suicide Clusters: A Review of Risk Factors and Mechanisms

    Science.gov (United States)

    Haw, Camilla; Hawton, Keith; Niedzwiedz, Claire; Platt, Steve

    2013-01-01

    Suicide clusters, although uncommon, cause great concern in the communities in which they occur. We searched the world literature on suicide clusters and describe the risk factors and proposed psychological mechanisms underlying the spatio-temporal clustering of suicides (point clusters). Potential risk factors include male gender, being an…

  7. Suicide Clusters: A Review of Risk Factors and Mechanisms

    Science.gov (United States)

    Haw, Camilla; Hawton, Keith; Niedzwiedz, Claire; Platt, Steve

    2013-01-01

    Suicide clusters, although uncommon, cause great concern in the communities in which they occur. We searched the world literature on suicide clusters and describe the risk factors and proposed psychological mechanisms underlying the spatio-temporal clustering of suicides (point clusters). Potential risk factors include male gender, being an…

  8. FunGeneClusterS

    DEFF Research Database (Denmark)

    Vesth, Tammi Camilla; Brandl, Julian; Andersen, Mikael Rørdam

    2016-01-01

    and industrial biotechnology applications. We have previously published a method for accurate prediction of clusters from genome and transcriptome data, which could also suggest cross-chemistry, however, this method was limited both in the number of parameters which could be adjusted as well as in user......Secondary metabolites of fungi are receiving an increasing amount of interest due to their prolific bioactivities and the fact that fungal biosynthesis of secondary metabolites often occurs from co-regulated and co-located gene clusters. This makes the gene clusters attractive for synthetic biology...

  9. Quotients of cluster categories

    OpenAIRE

    Jorgensen, Peter

    2007-01-01

    Higher cluster categories were recently introduced as a generalization of cluster categories. This paper shows that in Dynkin types A and D, half of all higher cluster categories are actually just quotients of cluster categories. The other half can be obtained as quotients of 2-cluster categories, the "lowest" type of higher cluster categories. Hence, in Dynkin types A and D, all higher cluster phenomena are implicit in cluster categories and 2-cluster categories. In contrast, the same is not...

  10. Nonrandom distribution of interhomolog recombination events induced by breakage of a dicentric chromosome in Saccharomyces cerevisiae.

    Science.gov (United States)

    Song, Wei; Gawel, Malgorzata; Dominska, Margaret; Greenwell, Patricia W; Hazkani-Covo, Einat; Bloom, Kerry; Petes, Thomas D

    2013-05-01

    Dicentric chromosomes undergo breakage in mitosis, resulting in chromosome deletions, duplications, and translocations. In this study, we map chromosome break sites of dicentrics in Saccharomyces cerevisiae by a mitotic recombination assay. The assay uses a diploid strain in which one homolog has a conditional centromere in addition to a wild-type centromere, and the other homolog has only the wild-type centromere; the conditional centromere is inactive when cells are grown in galactose and is activated when the cells are switched to glucose. In addition, the two homologs are distinguishable by multiple single-nucleotide polymorphisms (SNPs). Under conditions in which the conditional centromere is activated, the functionally dicentric chromosome undergoes double-stranded DNA breaks (DSBs) that can be repaired by mitotic recombination with the homolog. Such recombination events often lead to loss of heterozygosity (LOH) of SNPs that are centromere distal to the crossover. Using a PCR-based assay, we determined the position of LOH in multiple independent recombination events to a resolution of ∼4 kb. This analysis shows that dicentric chromosomes have recombination breakpoints that are broadly distributed between the two centromeres, although there is a clustering of breakpoints within 10 kb of the conditional centromere.

  11. Regional Innovation Clusters

    Data.gov (United States)

    Small Business Administration — The Regional Innovation Clusters serve a diverse group of sectors and geographies. Three of the initial pilot clusters, termed Advanced Defense Technology clusters,...

  12. Issues Relating to Study Design and Risk of Bias When Including Non-Randomized Studies in Systematic Reviews on the Effects of Interventions

    Science.gov (United States)

    Higgins, Julian P. T.; Ramsay, Craig; Reeves, Barnaby C.; Deeks, Jonathan J.; Shea, Beverley; Valentine, Jeffrey C.; Tugwell, Peter; Wells, George

    2013-01-01

    Non-randomized studies may provide valuable evidence on the effects of interventions. They are the main source of evidence on the intended effects of some types of interventions and often provide the only evidence about the effects of interventions on long-term outcomes, rare events or adverse effects. Therefore, systematic reviews on the effects…

  13. Synonymous codon usage in different protein secondary structural classes of human genes: Implication for increased non-randomness of GC3 rich genes towards protein stability

    Indian Academy of Sciences (India)

    Pamela Mukhopadhyay; Surajit Basak; Tapash Chandra Ghosh

    2007-08-01

    The relationship between the synonymous codon usage and different protein secondary structural classes were investigated using 401 Homo sapiens proteins extracted from Protein Data Bank (PDB). A simple Chi-square test was used to assess the significance of deviation of the observed and expected frequencies of 59 codons at the level of individual synonymous families in the four different protein secondary structural classes. It was observed that synonymous codon families show non-randomness in codon usage in four different secondary structural classes. However, when the genes were classified according to their GC3 levels there was an increase in non-randomness in high GC3 group of genes. The non-randomness in codon usage was further tested among the same protein secondary structures belonging to four different protein folding classes of high GC3 group of genes. The results show that in each of the protein secondary structural unit there exist some synonymous family that shows class specific codonusage pattern. Moreover, there is an increased non-random behaviour of synonymous codons in sheet structure of all secondary structural classes in high GC3 group of genes. Biological implications of these results have been discussed.

  14. Issues Relating to Confounding and Meta-analysis When Including Non-Randomized Studies in Systematic Reviews on the Effects of Interventions

    Science.gov (United States)

    Valentine, Jeffrey C.; Thompson, Simon G.

    2013-01-01

    Background: Confounding caused by selection bias is often a key difference between non-randomized studies (NRS) and randomized controlled trials (RCTs) of interventions. Key methodological issues: In this third paper of the series, we consider issues relating to the inclusion of NRS in systematic reviews on the effects of interventions. We discuss…

  15. Evaluation of the Prevention and Reactivation Care Program (PReCaP) for the hospitalized elderly: A prospective nonrandomized controlled trial

    NARCIS (Netherlands)

    K.J.E. Asmus-Szepesi (Kirsten); L.E. Flinterman (Linda); M.A. Koopmanschap (Marc); A.P. Nieboer (Anna); T.J.E.M. Bakker (Ton); J.P. Mackenbach (Johan); E.W. Steyerberg (Ewout)

    2015-01-01

    textabstractBackground: The hospitalized elderly are at risk of functional decline. We evaluated the effects and care costs of a specialized geriatric rehabilitation program aimed at preventing functional decline among at-risk hospitalized elderly. Methods: The prospective nonrandomized controlled

  16. Cluster Radioactivity

    Science.gov (United States)

    Poenaru, Dorin N.; Greiner, Walter

    One of the rare examples of phenomena predicted before experimental discovery, offers the opportunity to introduce fission theory based on the asymmetric two center shell model. The valleys within the potential energy surfaces are due to the shell effects and are clearly showing why cluster radioactivity was mostly detected in parent nuclei leading to a doubly magic lead daughter. Saddle point shapes can be determined by solving an integro-differential equation. Nuclear dynamics allows us to calculate the half-lives. The following cluster decay modes (or heavy particle radioactivities) have been experimentally confirmed: 14C, 20O, 23F, 22,24-26Ne, 28,30Mg, 32,34Si with half-lives in good agreement with predicted values within our analytical superasymmetric fission model. The preformation probability is calculated as the internal barrier penetrability. An universal curve is described and used as an alternative for the estimation of the half-lives. The macroscopic-microscopic method was extended to investigate two-alpha accompanied fission and true ternary fission. The methods developed in nuclear physics are also adapted to study the stability of deposited atomic clusters on the planar surfaces.

  17. Non-random crosslinking of polysulphone-polysiloxane alternating block copolymers under irradiation

    Science.gov (United States)

    Xinfang, Chen; Chunshan, Zhang

    In this paper the effects of radiation on polysulphone-polysiloxane segmented copolymers have been investigated. The experimental observations indicate that the crosslinking reaction occurs primarily between siloxane segments and the intermolecular crosslinking of isopropylidene groups of adjacent polysulphone segments also takes place after the irradiation of higher doses. From the non-randon radiation crosslinking model which the block copolymer follows, the relationship between sol fraction and crosslink density is derived by a statistical method. The radiation crosslinking structure of block copolymers prepared by polycondensation of prepolymers, polysulphone and polysiloxane, can be controled by changing the average molecular weights of two prepolymers and the ratio of one component to the other.

  18. Cross section measurements of the processes occurring in the fragmentation of H{sub n}{sup +} (3 {<=} n {<=} 35) hydrogen clusters induced by high speed (60 keV/u) collisions on helium atoms; Mesure des sections efficaces des differents processus intervenant dans la fragmentation d`agregats d`hydrogene H{sub n}{sup +} (3 {<=} n {<=} 35) induite par collision a haute vitesse (60 keV/u) sur un atome d`helium

    Energy Technology Data Exchange (ETDEWEB)

    Louc, Sandrine [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-09-15

    Different processes involved in the fragmentation of ionised hydrogen clusters H{sub 3} + (H{sub 2}){sub (n-3)/2} (n = 5-35) have been studied in the same experiment: the fragmentation of the cluster is induced by the collision with an helium atom at high velocity ({approx_equal} c/100). The collision is realised in reversed kinematic - clusters are accelerated - which allows the detection of neutral and charged fragments. The different channels of fragmentation are identified by using coincidence techniques. For all the cluster sizes studied the capture cross sections of one electron of the target by the cluster is equal to the capture cross section of the H{sub 3}{sup +} ion. In the same way, the dissociation cross section of the H{sub 3}{sup +} core of the cluster does not depend on cluster size. These fragmentation processes are due to the interaction of H{sub 3}{sup +} core of the cluster and the helium atom without ionization of another component of the cluster. On the contrary, the cross sections of loss of one, two and three molecules by the cluster and the dissociation cross section of the cluster in all its molecular components depends strongly on the cluster size. This dependence is different from the one measured for the metastable decay of the cluster. Thus, the process of loss of molecules induced by a collision should correspond to a different dissociation mechanism. In regard of the singularities observed for the size dependence, the H{sub 9}{sup +}, H{sub 15}{sup +}, H{sub 19}{sup +} and H{sub 29}{sup +} clusters could be the `core` of the biggest clusters. These observation are in agreement with the size effects of smaller magnitude observed for the dissociation cross section (all the processes). The values of the cross section for the process of at least one ionization of the cluster indicate that about 80% of the fragmentation events result from this process. (author) 114 refs., 74 figs., 9 tabs.

  19. Non-random retention of protein-coding overlapping genes in Metazoa

    Directory of Open Access Journals (Sweden)

    Bork Peer

    2008-04-01

    Full Text Available Abstract Background Although the overlap of transcriptional units occurs frequently in eukaryotic genomes, its evolutionary and biological significance remains largely unclear. Here we report a comparative analysis of overlaps between genes coding for well-annotated proteins in five metazoan genomes (human, mouse, zebrafish, fruit fly and worm. Results For all analyzed species the observed number of overlapping genes is always lower than expected assuming functional neutrality, suggesting that gene overlap is negatively selected. The comparison to the random distribution also shows that retained overlaps do not exhibit random features: antiparallel overlaps are significantly enriched, while overlaps lying on the same strand and those involving coding sequences are highly underrepresented. We confirm that overlap is mostly species-specific and provide evidence that it frequently originates through the acquisition of terminal, non-coding exons. Finally, we show that overlapping genes tend to be significantly co-expressed in a breast cancer cDNA library obtained by 454 deep sequencing, and that different overlap types display different patterns of reciprocal expression. Conclusion Our data suggest that overlap between protein-coding genes is selected against in Metazoa. However, when retained it may be used as a species-specific mechanism for the reciprocal regulation of neighboring genes. The tendency of overlaps to involve non-coding regions of the genes leads to the speculation that the advantages achieved by an overlapping arrangement may be optimized by evolving regulatory non-coding transcripts.

  20. Chemical evolution of star clusters.

    Science.gov (United States)

    van Loon, Jacco Th

    2010-02-28

    I discuss the chemical evolution of star clusters, with emphasis on old Galactic globular clusters (GCs), in relation to their formation histories. GCs are clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of GCs in dwarf galaxies has been suggested, present-day dwarf galaxies are not representative of the gravitational potential wells within which the GCs formed. Instead, a formation deep within the proto-Galaxy or within dark-matter mini-haloes might be favoured. Not all GCs may have formed and evolved similarly. In particular, we may need to distinguish Galactic Halo from Galactic Bulge clusters.

  1. An Automatic Clustering Technique for Optimal Clusters

    CERN Document Server

    Pavan, K Karteeka; Rao, A V Dattatreya; 10.5121/ijcsea.2011.1412

    2011-01-01

    This paper proposes a simple, automatic and efficient clustering algorithm, namely, Automatic Merging for Optimal Clusters (AMOC) which aims to generate nearly optimal clusters for the given datasets automatically. The AMOC is an extension to standard k-means with a two phase iterative procedure combining certain validation techniques in order to find optimal clusters with automation of merging of clusters. Experiments on both synthetic and real data have proved that the proposed algorithm finds nearly optimal clustering structures in terms of number of clusters, compactness and separation.

  2. Nuclear Deformation Effects in the Cluster Radioactivity

    OpenAIRE

    Misicu, S.; Protopopescu, D.(University of Glasgow, Glasgow, G12 8QQ, United Kingdom)

    1998-01-01

    We investigate the influence of the nuclear deformation on the decay rates of some cluster emission processes. The interaction between the daughter and the cluster is given by a double folding potential including quadrupole and hexadecupole deformed densities of both fragments. The nuclear part of the nucleus-nucleus interaction is density dependent and at small distances a repulsive core in the potential will occur. In the frame of the WKB- approximation the assault frequency of the cluster ...

  3. Ecological Interspecific Relationship and Clustering of Autumn -Occurring Weed Communities in Tea Gardens of Yixing City,Jiangsu Province%江苏省宜兴市茶园秋季杂草种间生态关系及群落分类

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    A survey of weed species,density and height was conducted in Yixing tea gardens to estimate the weed relative abundance and importance values in October of 201 3.The niche breadth and niche overlap values of selected 28 main weeds with 20% frequency were calculated from the obtained data,and a two -dimensional scatter plot of DCA ordination was drawn based on relevant values.There were 80 weed species,belonging to 71 genera of 40 families.Among them,the occurrence frequency of 28 weed species was over 20%.Among these 28 species,Rubus hirsutus,Vicia sativa,Oxalis corniculata,Paederia scandens var.to-mentosa,and Geranium carolinianum had wider niche breadth than those of other species,being the important weeds in Yixing tea gardens.The highest niche overlap values were found between R.hirsutus,P.scandens var.tomentosa,Sonchus oleraceus,Conyza canadensis, Digitaria sanguinalis,Crassocephalum crepidioides,Emilia sonchifolia,Cayratia japonica,Trigonotis peduncularis,Eleusine indica,Rostellularia procumbens and Setaira viridis that were highly competitive for available resources.Therefore they are the species posing the greatest harm to tea plants.All sampling sites were quantitatively clustered into five groups inclu-ding basalt soil tea garden,non plowed and general -managed tea garden,plowed and well -managed tea garden,plowed and fine -managed tea garden,non plowed non chemical weeding,and well -managed old tea garden based on the simi-larity coefficient.Dominant weeds were different among five groups and formed relatively different weed communities in the tea gardens.%2013年10月对江苏省宜兴市丘陵茶园秋季杂草发生种类、数量、高度等进行调查,将其转换成相对多度和重要值数据,在此基础上计测了宜兴丘陵茶园28种主要杂草的生态位宽度和生态位重叠值,用 DCA 排序法作出反映杂草生态学相似程度的 DCA 排序图,并对不同样地杂草类群进行聚类分析。结果表明:宜兴

  4. Symptomatic or prophylactic treatment of weekend migraine: an open-label, nonrandomized, comparison study of frovatriptan versus naproxen sodium versus no therapy

    Directory of Open Access Journals (Sweden)

    Guidotti M

    2013-01-01

    Full Text Available Mario Guidotti,1 Caterina Barrilà,1 Serena Leva,1 Claudio De Piazza,1 Stefano Omboni21Department of Neurology, Valduce Hospital, Como, 2Italian Institute of Telemedicine, Varese, ItalyBackground: Migraine often occurs during weekends. The efficacy of frovatriptan, naproxen sodium, or no therapy for the acute or prophylactic treatment of weekend migraineurs was tested in an open-label, nonrandomized pilot study.Methods: Twenty-eight subjects (mean age 36 ± 12 years, including 18 females suffering from migraine without aura were followed up for six consecutive weekends. No treatment was administered during the first two weekends. On the third and fourth weekends, patients were given frovatriptan 2.5 mg and on the fifth and sixth weekends naproxen sodium 500 mg. Treatment was taken on Saturday and Sunday morning, regardless of the occurrence of migraine. Efficacy was evaluated through a diary, where patients reported the severity of migraine on a scale from 0 (no migraine to 10 (severe migraine and use of rescue medication.Results: The migraine severity score was significantly lower with frovatriptan (4.8 [95% confidence interval (CI 3.8–5.9] than with naproxen sodium (5.7 [CI 5.1–6.4], P < 0.05 versus frovatriptan or no therapy (6.6 [6.2–7.0], P < 0.01 versus frovatriptan. The difference in favor of frovatriptan was more striking in patients not taking rescue medication (frovatriptan, 1.9 [1.5–2.3] versus naproxen sodium 3.6 [3.0–4.2], P < 0.001 and versus no therapy (5.1 [4.4–5.8], P < 0.001 and on the second day of treatment. The rate of use of rescue medication was significantly (P < 0.05 lower on frovatriptan (12.5% than on naproxen sodium (31.3% or no therapy (56.3%.Conclusion: This pilot study provides the first evidence of the efficacy of a second-generation triptan as symptomatic or prophylactic treatment for weekend migraine.Keywords: migraine, frovatriptan, naproxen sodium, weekend

  5. Nonrandomized Trial of Feasibility and Acceptability of Strategies for Promotion of Soapy Water as a Handwashing Agent in Rural Bangladesh.

    Science.gov (United States)

    Ashraf, Sania; Nizame, Fosiul A; Islam, Mahfuza; Dutta, Notan C; Yeasmin, Dalia; Akhter, Sadika; Abedin, Jaynal; Winch, Peter J; Ram, Pavani K; Unicomb, Leanne; Leontsini, Elli; Luby, Stephen P

    2017-02-08

    We conducted a nonrandomized trial of strategies to promote soapy water for handwashing in rural Bangladesh and measured uptake. We enrolled households with children promotion of soapy water (N = 120), soapy water promotion plus handwashing stations (N = 103), and soapy water promotion, stations plus detergent refills (N = 90); we also enrolled control households (N = 72). Our handwashing stations included tap-fitted buckets and soapy water bottles. Community promoters visited households and held community meetings to demonstrate soapy water preparation and promote handwashing at key times. Field workers measured uptake 4 months later. In-depth interviews and focus group discussions assessed factors associated with uptake. More households had soapy water at the handwashing place in progressively intensive arms: 18% (promotion), 60% (promotion plus station), and 71% (promotion, station with refills). Compared with the promotion-only arm, more households that received stations had soapy water at the primary handwashing station (44%, P ≤ 0.001; 71%, P < 0.001 with station plus detergent refill). Qualitative findings highlighted several dimensions that affected use: contextual (shared courtyard), psychosocial (perceived value), and technology dimensions (ease of use, convenience). Soapy water may increase habitual handwashing by addressing barriers of cost and availability of handwashing agents near water sources. Further research should inform optimal strategies to scale-up soapy water as a handwashing agent to study health impact.

  6. Randomly and Non-Randomly Missing Renal Function Data in the Strong Heart Study: A Comparison of Imputation Methods.

    Science.gov (United States)

    Shara, Nawar; Yassin, Sayf A; Valaitis, Eduardas; Wang, Hong; Howard, Barbara V; Wang, Wenyu; Lee, Elisa T; Umans, Jason G

    2015-01-01

    Kidney and cardiovascular disease are widespread among populations with high prevalence of diabetes, such as American Indians participating in the Strong Heart Study (SHS). Studying these conditions simultaneously in longitudinal studies is challenging, because the morbidity and mortality associated with these diseases result in missing data, and these data are likely not missing at random. When such data are merely excluded, study findings may be compromised. In this article, a subset of 2264 participants with complete renal function data from Strong Heart Exams 1 (1989-1991), 2 (1993-1995), and 3 (1998-1999) was used to examine the performance of five methods used to impute missing data: listwise deletion, mean of serial measures, adjacent value, multiple imputation, and pattern-mixture. Three missing at random models and one non-missing at random model were used to compare the performance of the imputation techniques on randomly and non-randomly missing data. The pattern-mixture method was found to perform best for imputing renal function data that were not missing at random. Determining whether data are missing at random or not can help in choosing the imputation method that will provide the most accurate results.

  7. Non-random spatial coupling induces desynchronization, chaos and multistability in a predator-prey-resource system.

    Science.gov (United States)

    Suzuki, Kenta; Yoshida, Takehito

    2012-05-07

    The metacommunity perspective has attracted much attention recently, but the understanding of how dispersal between local communities alters their ecological dynamics is still limited, especially regarding the effect of non-random, unequal dispersal of organisms. This is a study of a three-trophic-level (predator-prey-resource) system that is connected by different manners of dispersal. The model is based on a well-studied experimental system cultured in chemostats (continuous flow-through culture), which consists of rotifer predator, algal prey and nutrient. In the model, nutrient dispersal can give rise to multistability when the two systems are connected by nutrient dispersal, whereas three-trophic-level systems tend to show a rich dynamical behavior, e.g. antisynchronous or asynchronous oscillations including chaos. Although the existence of multistability was already known in two-trophic-level (predator-prey) systems, it was confined to a small range of dispersal rate. In contrast, the multistability in the three-trophic-level system is found in a broader range of dispersal rate. The results suggest that, in three-trophic-level systems, the dispersal of nutrient not only alters population dynamics of local systems but can also cause regime shifts such as a transition to different oscillation phases.

  8. Nonrandomized Trial of Feasibility and Acceptability of Strategies for Promotion of Soapy Water as a Handwashing Agent in Rural Bangladesh

    Science.gov (United States)

    Ashraf, Sania; Nizame, Fosiul A.; Islam, Mahfuza; Dutta, Notan C.; Yeasmin, Dalia; Akhter, Sadika; Abedin, Jaynal; Winch, Peter J.; Ram, Pavani K.; Unicomb, Leanne; Leontsini, Elli; Luby, Stephen P.

    2017-01-01

    We conducted a nonrandomized trial of strategies to promote soapy water for handwashing in rural Bangladesh and measured uptake. We enrolled households with children promotion of soapy water (N = 120), soapy water promotion plus handwashing stations (N = 103), and soapy water promotion, stations plus detergent refills (N = 90); we also enrolled control households (N = 72). Our handwashing stations included tap-fitted buckets and soapy water bottles. Community promoters visited households and held community meetings to demonstrate soapy water preparation and promote handwashing at key times. Field workers measured uptake 4 months later. In-depth interviews and focus group discussions assessed factors associated with uptake. More households had soapy water at the handwashing place in progressively intensive arms: 18% (promotion), 60% (promotion plus station), and 71% (promotion, station with refills). Compared with the promotion-only arm, more households that received stations had soapy water at the primary handwashing station (44%, P ≤ 0.001; 71%, P strategies to scale-up soapy water as a handwashing agent to study health impact. PMID:28025233

  9. Randomly and Non-Randomly Missing Renal Function Data in the Strong Heart Study: A Comparison of Imputation Methods.

    Directory of Open Access Journals (Sweden)

    Nawar Shara

    Full Text Available Kidney and cardiovascular disease are widespread among populations with high prevalence of diabetes, such as American Indians participating in the Strong Heart Study (SHS. Studying these conditions simultaneously in longitudinal studies is challenging, because the morbidity and mortality associated with these diseases result in missing data, and these data are likely not missing at random. When such data are merely excluded, study findings may be compromised. In this article, a subset of 2264 participants with complete renal function data from Strong Heart Exams 1 (1989-1991, 2 (1993-1995, and 3 (1998-1999 was used to examine the performance of five methods used to impute missing data: listwise deletion, mean of serial measures, adjacent value, multiple imputation, and pattern-mixture. Three missing at random models and one non-missing at random model were used to compare the performance of the imputation techniques on randomly and non-randomly missing data. The pattern-mixture method was found to perform best for imputing renal function data that were not missing at random. Determining whether data are missing at random or not can help in choosing the imputation method that will provide the most accurate results.

  10. Eclipse period of R1 plasmids during downshift from elevated copy number: Nonrandom selection of copies for replication.

    Science.gov (United States)

    Olsson, Jan A; Berg, Otto; Nordström, Kurt; Dasgupta, Santanu

    2012-03-01

    The classical Meselson-Stahl density-shift method was used to study replication of pOU71, a runaway-replication derivative of plasmid R1 in Escherichia coli. The miniplasmid maintained the normal low copy number of R1 during steady growth at 30°C, but as growth temperatures were raised above 34°C, the copy number of the plasmid increased to higher levels, and at 42°C, it replicated without control in a runaway replication mode with lethal consequences for the host. The eclipse periods (minimum time between successive replication of the same DNA) of the plasmid shortened with rising copy numbers at increasing growth temperatures (Olsson et al., 2003). In this work, eclipse periods were measured during downshifts in copy number of pOU71 after it had replicated at 39 and 42°C, resulting in 7- and 50-fold higher than normal plasmid copy number per cell, respectively. Eclipse periods for plasmid replication, measured during copy number downshift, suggested that plasmid R1, normally selected randomly for replication, showed a bias such that a newly replicated DNA had a higher probability of replication compared to the bulk of the R1 population. However, even the unexpected nonrandom replication followed the copy number kinetics such that every generation, the plasmids underwent the normal inherited number of replication, n, independent of the actual number of plasmid copies in a newborn cell.

  11. Does balneotherapy with low radon concentration in water influence the endocrine system? A controlled non-randomized pilot study.

    Science.gov (United States)

    Nagy, Katalin; Berhés, István; Kovács, Tibor; Kávási, Norbert; Somlai, János; Bender, Tamás

    2009-08-01

    Radon bath is a well-established modality of balneotherapy for the management of degenerative musculoskeletal disorders. The present study was conducted to ascertain whether baths of relatively low (80 Bq/l) radon concentration have any influence on the functioning of the endocrine system. In the study, a non-randomized pilot study, 27 patients with degenerative musculoskeletal disorders received 30-min radon baths (of 31-32 degrees C temperature and 80 Bq/l average radon concentration) daily, for 15 days. Twenty-five patients with matching pathologies were subjected to balneotherapy according to the same protocol, using thermal water with negligible radon content (6 Bq/l). Serum thyroid stimulating hormone, prolactin, cortisol, adrenocorticotropic hormone, and dehydroepiandrosterone levels were measured before and after a balneotherapy course of 15 sessions. Comparison of the accumulated data using the Wilcoxon test did not reveal any significant difference between pre- and post-treatment values or between the two patient groups. It is noted that while the beneficial effects of balneotherapy with radon-containing water on degenerative disorders is widely known, only few data have been published in the literature on its effect on endocrine functions. The present study failed to demonstrate any substantial effect of thermal water with relatively low radon content on the functioning of the endocrine system.

  12. Nonrandom X chromosome inactivation in natural killer cells from obligate carriers of X-linked severe combined immunodeficiency

    Energy Technology Data Exchange (ETDEWEB)

    Wengler, G.S.; Parolini, O.; Conley, M.E. (Univ. of Tennessee, Memphis (United States) St. Jude Children' s Research Hospital, Memphis, TN (United States)); Allen, R.C. (Baylor College of Medicine, Houston, TX (United States)); Smith, H. (St. Jude Children' s Research Hospital, Memphis, TN (United States))

    1993-01-15

    X-linked severe combined immunodeficiency (XSCID) is characterized by hypogammaglobulinemia, markedly reduced numbers of T cells, absent mitogen responses, decreased numbers of NK cells, and normal or elevated numbers of B cells. The abnormalities in the NK cell and B cell lineages could be attributed to dependence of these cell lineages on T cells or T cell-derived factors, or to expression of the XSCID gene defect in these cell lineages. In past experiments, the authors have examined X chromosome inactivation patterns in T cells and cultured B cells from female obligate carriers of XSCID and have found that both cell lineages demonstrate nonrandom X chromosome inactivation. This indicates that the gene defect is intrinsic to both of these cell lineages. In the present experiments, a polymerase chain reaction technique was used to evaluate X chromosome inactivation patterns in highly purified populations of freshly isolated NK cells, B cells, CD4[sup +] cells, and CD8[sup +] cells from three obligate carriers of XSCID. All four lymphoid cell populations from these three women exhibited exclusive use of a single X as the active X. In contrast, both X chromosomes were used as the active X in neutrophils and monocytes. These findings indicate that the XSCID gene is expressed in the NK cell lineage as well as in T cells and B cells. This observation makes it highly unlikely that the XSCID gene is involved in Ag receptor gene rearrangements. 21 refs., 4 figs.

  13. Botulinum toxin injection versus lateral internal sphincterotomy in the treatment of chronic anal fissure: a non-randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ulusoy Nefise B

    2004-03-01

    Full Text Available Abstract Background Although lateral internal sphincterotomy is the gold-standard treatment for chronic anal fissure, intrasphincteric injection of botulinum toxin seems to be a reliable new option. The aim of this non-randomized study is to compare the effect of lateral internal sphincterotomy and botulinum toxin injection treatments on the outcome and reduction of anal sphincter pressures in patients with chronic anal fissure. Methods Patients with chronic anal fissure were treated with either botulinum toxin injection or lateral internal sphincterotomy by their own choice. Maximal resting pressure and maximal squeeze pressure measurements were performed before and 2 weeks after treatments by anal manometry. Patients were followed for fissure relapse during 14 months. Results Twenty-one consecutive outpatients with posterior chronic anal fissure were enrolled. Eleven patients underwent surgery and ten patients received botulinum toxin injection treatment. Before the treatment, anal pressures were found to be similar in both groups. After the treatment, the maximal resting pressures were reduced from 104 ± 22 mmHg to 86 ± 15 mmHg in the surgery group (p 0.05 in the surgery group, and from 117 ± 62 mmHg to 76 ± 34 (p 0.05. There were no relapses during the 14 months of follow up. Conclusion Lateral internal sphincterotomy and botulinum toxin injection treatments both seem to be equally effective in the treatment of chronic anal fissure.

  14. Systems-level chromosomal parameters represent a suprachromosomal basis for the non-random chromosomal arrangement in human interphase nuclei

    Science.gov (United States)

    Fatakia, Sarosh N.; Mehta, Ishita S.; Rao, Basuthkar J.

    2016-01-01

    Forty-six chromosome territories (CTs) are positioned uniquely in human interphase nuclei, wherein each of their positions can range from the centre of the nucleus to its periphery. A non-empirical basis for their non-random arrangement remains unreported. Here, we derive a suprachromosomal basis of that overall arrangement (which we refer to as a CT constellation), and report a hierarchical nature of the same. Using matrix algebra, we unify intrinsic chromosomal parameters (e.g., chromosomal length, gene density, the number of genes per chromosome), to derive an extrinsic effective gene density matrix, the hierarchy of which is dominated largely by extrinsic mathematical coupling of HSA19, followed by HSA17 (human chromosome 19 and 17, both preferentially interior CTs) with all CTs. We corroborate predicted constellations and effective gene density hierarchy with published reports from fluorescent in situ hybridization based microscopy and Hi-C techniques, and delineate analogous hierarchy in disparate vertebrates. Our theory accurately predicts CTs localised to the nuclear interior, which interestingly share conserved synteny with HSA19 and/or HSA17. Finally, the effective gene density hierarchy dictates how permutations among CT position represents the plasticity within its constellations, based on which we suggest that a differential mix of coding with noncoding genome modulates the same. PMID:27845379

  15. Azacytidine and decitabine induce gene-specific and non-random DNA demethylation in human cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Sabine Hagemann

    Full Text Available The DNA methyltransferase inhibitors azacytidine and decitabine represent archetypal drugs for epigenetic cancer therapy. To characterize the demethylating activity of azacytidine and decitabine we treated colon cancer and leukemic cells with both drugs and used array-based DNA methylation analysis of more than 14,000 gene promoters. Additionally, drug-induced demethylation was compared to methylation patterns of isogenic colon cancer cells lacking both DNA methyltransferase 1 (DNMT1 and DNMT3B. We show that drug-induced demethylation patterns are highly specific, non-random and reproducible, indicating targeted remethylation of specific loci after replication. Correspondingly, we found that CG dinucleotides within CG islands became preferentially remethylated, indicating a role for DNA sequence context. We also identified a subset of genes that were never demethylated by drug treatment, either in colon cancer or in leukemic cell lines. These demethylation-resistant genes were enriched for Polycomb Repressive Complex 2 components in embryonic stem cells and for transcription factor binding motifs not present in demethylated genes. Our results provide detailed insights into the DNA methylation patterns induced by azacytidine and decitabine and suggest the involvement of complex regulatory mechanisms in drug-induced DNA demethylation.

  16. Family cluster of Mayaro fever, Venezuela.

    Science.gov (United States)

    Torres, Jaime R; Russell, Kevin L; Vasquez, Clovis; Barrera, Roberto; Tesh, Robert B; Salas, Rosalba; Watts, Douglas M

    2004-07-01

    A cluster of protracted migratory polyarthritis involving four adult family members occurred in January 2000 after a brief overnight outing in a rural area of Venezuela. Laboratory testing demonstrated Mayaro virus as the cause of the cluster. These results documented the first human cases of Mayaro virus in Venezuela.

  17. Family Cluster of Mayaro Fever, Venezuela

    OpenAIRE

    Jaime R. Torres; Russell, Kevin L; Vasquez, Clovis; Robert B Tesh; Salas, Rosalba; Watts, Douglas M.

    2004-01-01

    A cluster of protracted migratory polyarthritis involving four adult family members occurred in January 2000 after a brief overnight outing in a rural area of Venezuela. Laboratory testing demonstrated Mayaro virus as the cause of the cluster. These results documented the first human cases of Mayaro virus in Venezuela.

  18. Heavy hitters via cluster-preserving clustering

    DEFF Research Database (Denmark)

    Larsen, Kasper Green; Nelson, Jelani; Nguyen, Huy L.

    2016-01-01

    , providing correctness whp. In fact, a simpler version of our algorithm for p = 1 in the strict turnstile model answers queries even faster than the "dyadic trick" by roughly a log n factor, dominating it in all regards. Our main innovation is an efficient reduction from the heavy hitters to a clustering...... problem in which each heavy hitter is encoded as some form of noisy spectral cluster in a much bigger graph, and the goal is to identify every cluster. Since every heavy hitter must be found, correctness requires that every cluster be found. We thus need a "cluster-preserving clustering" algorithm......, that partitions the graph into clusters with the promise of not destroying any original cluster. To do this we first apply standard spectral graph partitioning, and then we use some novel combinatorial techniques to modify the cuts obtained so as to make sure that the original clusters are sufficiently preserved...

  19. Allergies and Asthma: They Often Occur Together

    Science.gov (United States)

    ... you miserable. A lot, as it turns out. Allergies and asthma often occur together. The same substances that trigger your hay fever symptoms, such as pollen, dust mites and pet dander, may also cause asthma signs ...

  20. Multiple Primary Cancers: Simultaneously Occurring Prostate ...

    African Journals Online (AJOL)

    2016-05-20

    May 20, 2016 ... occurring prostate cancer and other primary tumors-our experience and literature ... carcinoma, primary liver cell carcinoma, and thyroid follicular carcinoma in both ..... malignancies in women with papillary thyroid cancer.

  1. ST elevation occurring during stress testing

    Directory of Open Access Journals (Sweden)

    Diana Malouf

    2016-04-01

    Full Text Available A case is presented of significant reversible ST elevation occurring during treadmill testing, and the coronary anatomy and subsequent course are described, indicating that ischemia is a potential cause of this electrocardiographic finding.

  2. Trichotillomania and Co-occurring Anxiety

    Science.gov (United States)

    Grant, Jon E.; Redden, Sarah A.; Leppink, Eric W.; Chamberlain, Samuel R.

    2017-01-01

    Background Trichotillomania appears to be a fairly common disorder, with high rates of co-occurring anxiety disorders. Many individuals with trichotillomania also report that pulling worsens during periods of increased anxiety. Even with these clinical links to anxiety, little research has explored whether trichotillomania with co-occurring anxiety is a meaningful subtype. Methods 165 adults with trichotillomania were examined on a variety of clinical measures including symptom severity, functioning, and comorbidity. Participants also underwent cognitive testing assessing motor inhibition and cognitive flexibility. Clinical features and cognitive functioning were compared between those with current co-occurring anxiety disorders (i.e. social anxiety, generalized anxiety disorder, panic disorder, and anxiety disorder NOS) (n=38) and those with no anxiety disorder (n=127). Results Participants with trichotillomania and co-occurring anxiety reported significantly worse hair pulling symptoms, were more likely to have co-occurring depression, and were more likely to have a first-degree relative with obsessive compulsive disorder. Those with anxiety disorders also exhibited significantly worse motor inhibitory performance on a task of motor inhibition (stop-signal task). Conclusions This study suggests that anxiety disorders affect the clinical presentation of hair pulling behavior. Further research is needed to validate our findings and to consider whether treatments should be specially tailored differently for adults with trichotillomania who have co-occurring anxiety disorders, or more pronounced cognitive impairment. PMID:27668531

  3. Cluster Tree Based Hybrid Document Similarity Measure

    Directory of Open Access Journals (Sweden)

    M. Varshana Devi

    2015-10-01

    Full Text Available <Cluster tree based hybrid similarity measure is established to measure the hybrid similarity. In cluster tree, the hybrid similarity measure can be calculated for the random data even it may not be the co-occurred and generate different views. Different views of tree can be combined and choose the one which is significant in cost. A method is proposed to combine the multiple views. Multiple views are represented by different distance measures into a single cluster. Comparing the cluster tree based hybrid similarity with the traditional statistical methods it gives the better feasibility for intelligent based search. It helps in improving the dimensionality reduction and semantic analysis.

  4. Partitional clustering algorithms

    CERN Document Server

    2015-01-01

    This book summarizes the state-of-the-art in partitional clustering. Clustering, the unsupervised classification of patterns into groups, is one of the most important tasks in exploratory data analysis. Primary goals of clustering include gaining insight into, classifying, and compressing data. Clustering has a long and rich history that spans a variety of scientific disciplines including anthropology, biology, medicine, psychology, statistics, mathematics, engineering, and computer science. As a result, numerous clustering algorithms have been proposed since the early 1950s. Among these algorithms, partitional (nonhierarchical) ones have found many applications, especially in engineering and computer science. This book provides coverage of consensus clustering, constrained clustering, large scale and/or high dimensional clustering, cluster validity, cluster visualization, and applications of clustering. Examines clustering as it applies to large and/or high-dimensional data sets commonly encountered in reali...

  5. A prospective, non-randomized study of home use of mifepristone for medical abortion in the U.S.

    Science.gov (United States)

    Chong, Erica; Frye, Laura J; Castle, Jen; Dean, Gillian; Kuehl, Laurel; Winikoff, Beverly

    2015-09-01

    To determine the acceptability of taking mifepristone at home for early medical abortion in the United States. This prospective, non-randomized, open-label study at six Planned Parenthood centers gave women with pregnancies up to 63 days' gestation seeking medical abortion the choice of taking mifepristone in the center or at home. Participants were interviewed at a follow-up visit 1-2 weeks after mifepristone administration to assess their experience with the option they selected. Four-hundred women were enrolled between April 2013 and June 2014 of which 32% (n=128) chose to take mifepristone at home. Abortion success rates did not differ between home and center users (96% and 97%). Among home users, 82% reported taking the mifepristone at the time they planned with their provider and no participant took it after 63 days' gestation. The most common reason cited for selecting home use was scheduling flexibility and significantly more home users took misoprostol on the weekend (50% vs. 36%, p=.02). Home users were more likely than center users to report missing no days of work due to the abortion (47% vs. 28%, p=.08). Ninety-nine percent of home users reported that they would take mifepristone at home again and 96% would recommend home use to a friend. Offering this option did not increase the service delivery burden on study providers, who would recommend home use in the future for most participants. Home use of mifepristone is a highly acceptable practice for which there is current demand, and it should be offered as part of routine medical abortion services. Offering the option of home use of mifepristone to medical abortion patients can provide women and clinics with more flexibility while maintaining a safe, effective and acceptable service. These results provide support for telemedicine or pharmacy distribution. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Cortical Microtubule Arrays Are Initiated from a Nonrandom Prepattern Driven by Atypical Microtubule Initiation1[W][OA

    Science.gov (United States)

    Lindeboom, Jelmer J.; Lioutas, Antonios; Deinum, Eva E.; Tindemans, Simon H.; Ehrhardt, David W.; Emons, Anne Mie C.; Vos, Jan W.; Mulder, Bela M.

    2013-01-01

    The ordered arrangement of cortical microtubules in growing plant cells is essential for anisotropic cell expansion and, hence, for plant morphogenesis. These arrays are dismantled when the microtubule cytoskeleton is rearranged during mitosis and reassembled following completion of cytokinesis. The reassembly of the cortical array has often been considered as initiating from a state of randomness, from which order arises at least partly through self-organizing mechanisms. However, some studies have shown evidence for ordering at early stages of array assembly. To investigate how cortical arrays are initiated in higher plant cells, we performed live-cell imaging studies of cortical array assembly in tobacco (Nicotiana tabacum) Bright Yellow-2 cells after cytokinesis and drug-induced disassembly. We found that cortical arrays in both cases did not initiate randomly but with a significant overrepresentation of microtubules at diagonal angles with respect to the cell axis, which coincides with the predominant orientation of the microtubules before their disappearance from the cell cortex in preprophase. In Arabidopsis (Arabidopsis thaliana) root cells, recovery from drug-induced disassembly was also nonrandom and correlated with the organization of the previous array, although no diagonal bias was observed in these cells. Surprisingly, during initiation, only about one-half of the new microtubules were nucleated from locations marked by green fluorescent protein-γ-tubulin complex protein2-tagged γ-nucleation complexes (γ-tubulin ring complex), therefore indicating that a large proportion of early polymers was initiated by a noncanonical mechanism not involving γ-tubulin ring complex. Simulation studies indicate that the high rate of noncanonical initiation of new microtubules has the potential to accelerate the rate of array repopulation. PMID:23300168

  7. Effectiveness of a mindfulness-based intervention on oncology nurses' burnout and compassion fatigue symptoms: A non-randomized study.

    Science.gov (United States)

    Duarte, Joana; Pinto-Gouveia, José

    2016-12-01

    Job stress and burnout are highly frequent in healthcare professionals, and prevalence in nurses can be as high as 40%. Mindfulness-based interventions have been shown to be effective in reducing stress and increasing well-being in a wide range of populations and contexts. However, controlled studies with healthcare professionals, and especially nurses, are scarce. The aim of this study was to explore the effectiveness of an on-site, abbreviated mindfulness-based intervention for nurses, using a nonrandomized, wait-list comparison design. The effectiveness of the intervention was measured through several validated self-report measures that participants completed before and after the intervention, assessing burnout, compassion fatigue, psychological symptoms, mindfulness, self-compassion, experiential avoidances, rumination, and satisfaction with life. A sample of 94 oncology nurses agreed to participate in the study and self-selected into an experimental (n=45) and comparison condition (n=48). Complete data was obtained for 48 of the initial 94 participants, mainly due to poor follow-up data rather than high drop-out rate. Statistical analyses included a series of 2×2 ANOVAs and ANCOVAs. Results indicated that nurses in the intervention reported significant decreases in compassion fatigue, burnout, stress, experiential avoidance, and increases in satisfaction with life, mindfulness and self-compassion, with medium to large effect sizes. Nurses in the comparison group didn't present significant changes in these variables. Results also pointed to a high degree of acceptability of the intervention. This study provides preliminary evidence that mindfulness-based interventions may be efficacious in reducing oncology nurses' psychological symptoms and improving their overall well-being, and thus may be worthy of further study in this population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Comparative Evaluation of Liposomal Albendazole and Tablet-Albendazole Against Hepatic Cystic Echinococcosis: A Non-Randomized Clinical Trial.

    Science.gov (United States)

    Li, Haitao; Song, Tao; Shao, Yingmei; Aili, Tuergan; Ahan, Ayifuhan; Wen, Hao

    2016-01-01

    In this study, we aimed to compare the clinical efficacy of liposomal albendazole (L-ABZ) and tablet-albendazole (T-ABZ) for the treatment of human hepatic cystic echinococcosis (CE). Sixty patients with single cyst (CE1) or daughter cyst (CE2) were included in this study and were nonrandomly divided into the L-ABZ group (n = 30, 10  mg/kg per day, p.o., b.i.d.) and T-ABZ group (n = 30, 12-20 mg/kg per day, p.o., b.i.d.), respectively. The treatment duration lasted for 6 months, during which dynamic follow-up was carried out to evaluate the clinical efficacy through calculating the total effective rates (TERs). Measurement data and numerous data were analyzed by the chi-square test. Two-sided tests were performed for all the statistical tests. In our study, 2 patients were lost in the follow-up in the L-ABZ group. One patient was lost in the follow-up in the T-ABZ group, and 1 patient was withdrawal from the study due to receiving surgery. Significant difference was identified in the 3-month TERs of L-ABZ group and T-ABZ group (33.3% vs 76.7%, P  0.05). Based on our study, both T-ABZ and L-ABZ are effective for treating human CE. The TER in the L-ABZ group is superior to that of T-ABZ.

  9. Deep sequencing of the murine Igh repertoire reveals complex regulation of non-random V gene rearrangement frequencies

    Science.gov (United States)

    Choi, Nancy M.; Loguercio, Salvatore; Verma-Gaur, Jiyoti; Degner, Stephanie C.; Torkamani, Ali; Su, Andrew I.; Oltz, Eugene M.; Artyomov, Maxim; Feeney, Ann J.

    2013-01-01

    A diverse antibody repertoire is formed through the rearrangement of V, D, and J segments at the immunoglobulin heavy chain (Igh) loci. The C57BL/6 murine Igh locus has over 100 functional VH gene segments that can recombine to a rearranged DJH. While the non-random usage of VH genes is well documented, it is not clear what elements determine recombination frequency. To answer this question we conducted deep sequencing of 5′-RACE products of the Igh repertoire in pro-B cells, amplified in an unbiased manner. ChIP-seq results for several histone modifications and RNA polymerase II binding, RNA-seq for sense and antisense non-coding germline transcripts, and proximity to CTCF and Rad21 sites were compared to the usage of individual V genes. Computational analyses assessed the relative importance of these various accessibility elements. These elements divide the Igh locus into four epigenetically and transcriptionally distinct domains, and our computational analyses reveal different regulatory mechanisms for each region. Proximal V genes are relatively devoid of active histone marks and non-coding RNA in general, but having a CTCF site near their RSS is critical, suggesting that being positioned near the base of the chromatin loops is important for rearrangement. In contrast, distal V genes have higher levels of histone marks and non-coding RNA, which may compensate for their poorer RSSs and for being distant from CTCF sites. Thus, the Igh locus has evolved a complex system for the regulation of V(D)J rearrangement that is different for each of the four domains that comprise this locus. PMID:23898036

  10. Exceptional diversity, non-random distribution, and rapid evolution of retroelements in the B73 maize genome.

    Directory of Open Access Journals (Sweden)

    Regina S Baucom

    2009-11-01

    Full Text Available Recent comprehensive sequence analysis of the maize genome now permits detailed discovery and description of all transposable elements (TEs in this complex nuclear environment. Reiteratively optimized structural and homology criteria were used in the computer-assisted search for retroelements, TEs that transpose by reverse transcription of an RNA intermediate, with the final results verified by manual inspection. Retroelements were found to occupy the majority (>75% of the nuclear genome in maize inbred B73. Unprecedented genetic diversity was discovered in the long terminal repeat (LTR retrotransposon class of retroelements, with >400 families (>350 newly discovered contributing >31,000 intact elements. The two other classes of retroelements, SINEs (four families and LINEs (at least 30 families, were observed to contribute 1,991 and approximately 35,000 copies, respectively, or a combined approximately 1% of the B73 nuclear genome. With regard to fully intact elements, median copy numbers for all retroelement families in maize was 2 because >250 LTR retrotransposon families contained only one or two intact members that could be detected in the B73 draft sequence. The majority, perhaps all, of the investigated retroelement families exhibited non-random dispersal across the maize genome, with LINEs, SINEs, and many low-copy-number LTR retrotransposons exhibiting a bias for accumulation in gene-rich regions. In contrast, most (but not all medium- and high-copy-number LTR retrotransposons were found to preferentially accumulate in gene-poor regions like pericentromeric heterochromatin, while a few high-copy-number families exhibited the opposite bias. Regions of the genome with the highest LTR retrotransposon density contained the lowest LTR retrotransposon diversity. These results indicate that the maize genome provides a great number of different niches for the survival and procreation of a great variety of retroelements that have evolved to

  11. Exceptional diversity, non-random distribution, and rapid evolution of retroelements in the B73 maize genome.

    Science.gov (United States)

    Baucom, Regina S; Estill, James C; Chaparro, Cristian; Upshaw, Naadira; Jogi, Ansuya; Deragon, Jean-Marc; Westerman, Richard P; Sanmiguel, Phillip J; Bennetzen, Jeffrey L

    2009-11-01

    Recent comprehensive sequence analysis of the maize genome now permits detailed discovery and description of all transposable elements (TEs) in this complex nuclear environment. Reiteratively optimized structural and homology criteria were used in the computer-assisted search for retroelements, TEs that transpose by reverse transcription of an RNA intermediate, with the final results verified by manual inspection. Retroelements were found to occupy the majority (>75%) of the nuclear genome in maize inbred B73. Unprecedented genetic diversity was discovered in the long terminal repeat (LTR) retrotransposon class of retroelements, with >400 families (>350 newly discovered) contributing >31,000 intact elements. The two other classes of retroelements, SINEs (four families) and LINEs (at least 30 families), were observed to contribute 1,991 and approximately 35,000 copies, respectively, or a combined approximately 1% of the B73 nuclear genome. With regard to fully intact elements, median copy numbers for all retroelement families in maize was 2 because >250 LTR retrotransposon families contained only one or two intact members that could be detected in the B73 draft sequence. The majority, perhaps all, of the investigated retroelement families exhibited non-random dispersal across the maize genome, with LINEs, SINEs, and many low-copy-number LTR retrotransposons exhibiting a bias for accumulation in gene-rich regions. In contrast, most (but not all) medium- and high-copy-number LTR retrotransposons were found to preferentially accumulate in gene-poor regions like pericentromeric heterochromatin, while a few high-copy-number families exhibited the opposite bias. Regions of the genome with the highest LTR retrotransposon density contained the lowest LTR retrotransposon diversity. These results indicate that the maize genome provides a great number of different niches for the survival and procreation of a great variety of retroelements that have evolved to differentially

  12. Clustering and Community Detection with Imbalanced Clusters

    OpenAIRE

    Aksoylar, Cem; Qian, Jing; Saligrama, Venkatesh

    2016-01-01

    Spectral clustering methods which are frequently used in clustering and community detection applications are sensitive to the specific graph constructions particularly when imbalanced clusters are present. We show that ratio cut (RCut) or normalized cut (NCut) objectives are not tailored to imbalanced cluster sizes since they tend to emphasize cut sizes over cut values. We propose a graph partitioning problem that seeks minimum cut partitions under minimum size constraints on partitions to de...

  13. Global and Partial Errors in Stratified and Clustering Sampling

    OpenAIRE

    Giovanna Nicolini; Anna Lo Presti

    2005-01-01

    In this paper we split up the sampling error occurred in stratified and clustering sampling, called global error and measured by the variance of estimator, in many partial errors each one referred to a single stratum or cluster. In particular, we study, for clustering sampling, the empirical distribution of the homogeneity coefficient that is very important for settlement of partial errors.

  14. Forecasting seizures in dogs with naturally occurring epilepsy.

    Science.gov (United States)

    Howbert, J Jeffry; Patterson, Edward E; Stead, S Matt; Brinkmann, Ben; Vasoli, Vincent; Crepeau, Daniel; Vite, Charles H; Sturges, Beverly; Ruedebusch, Vanessa; Mavoori, Jaideep; Leyde, Kent; Sheffield, W Douglas; Litt, Brian; Worrell, Gregory A

    2014-01-01

    Seizure forecasting has the potential to create new therapeutic strategies for epilepsy, such as providing patient warnings and delivering preemptive therapy. Progress on seizure forecasting, however, has been hindered by lack of sufficient data to rigorously evaluate the hypothesis that seizures are preceded by physiological changes, and are not simply random events. We investigated seizure forecasting in three dogs with naturally occurring focal epilepsy implanted with a device recording continuous intracranial EEG (iEEG). The iEEG spectral power in six frequency bands: delta (0.1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), low-gamma (30-70 Hz), and high-gamma (70-180 Hz), were used as features. Logistic regression classifiers were trained to discriminate labeled pre-ictal and inter-ictal data segments using combinations of the band spectral power features. Performance was assessed on separate test data sets via 10-fold cross-validation. A total of 125 spontaneous seizures were detected in continuous iEEG recordings spanning 6.5 to 15 months from 3 dogs. When considering all seizures, the seizure forecasting algorithm performed significantly better than a Poisson-model chance predictor constrained to have the same time in warning for all 3 dogs over a range of total warning times. Seizure clusters were observed in all 3 dogs, and when the effect of seizure clusters was decreased by considering the subset of seizures separated by at least 4 hours, the forecasting performance remained better than chance for a subset of algorithm parameters. These results demonstrate that seizures in canine epilepsy are not randomly occurring events, and highlight the feasibility of long-term seizure forecasting using iEEG monitoring.

  15. Percieved functions of naturally occurring autobiographical memories

    DEFF Research Database (Denmark)

    Treebak, L. S.; Henriksen, J. R.; Lundhus, S.

    2005-01-01

    The main empirical reference on functions of autobiographical memories is still Hyman & Faries (1992) who used the cue-word-method and retrospective judgements. We used diaries to sample naturally occurring autobiographical memories and participants? perceived use of these. Results partly replicate...

  16. A 3-year multicentre randomized controlled trial of etonogestrel- and levonorgestrel-releasing contraceptive implants, with non-randomized matched copper-intrauterine device controls.

    Science.gov (United States)

    Bahamondes, Luis; Brache, Vivian; Meirik, Olav; Ali, Moazzam; Habib, Ndema; Landoulsi, Sihem

    2015-11-01

    Is there any difference in the clinical performance of the 3-year one-rod etonogestrel (ENG)- and the 5-year two-rod levonorgestrel (LNG)-releasing contraceptive implants during 3 years of insertion, and between implant and intrauterine device (IUD) contraception, in particular complaints possibly related to hormonal contraceptives? The cumulative contraceptive effectiveness after 3 years and method continuation through 2.5 years were not significantly different between ENG and LNG implants, but both outcomes were significantly worse in the non-randomized age-matched group of IUD users than in the combined implant group. ENG- and LNG-releasing implants are safe and highly efficacious contraceptives with pregnancy rates reported to be 0.0-0.5 per 100 women-years (W-Y). No head-to-head comparative study of the two implants has been undertaken, and little information is available on comparisons of complaints of side effects of implant and copper IUD users. This was an open parallel group RCT with 1:1 allocation ratio of the ENG and the LNG implants with non-randomized control group of women choosing TCu380A IUD to address lack of reliable data on common side effects typically attributed to the use of progestogen-only contraceptives. After device(s) placement, follow-ups were at 2 weeks, 3 and 6 months, and semi-annually thereafter for 3 years or until pregnancy, removal or expulsion of the implant/IUD occurred. The study took place in family planning clinics in Brazil, Chile, Dominican Republic, Hungary, Thailand, Turkey and Zimbabwe. Women seeking long-term contraception were enlisted after an eligibility check and informed consent, and 2982 women were enrolled: 1003, 1005 and 974 in the ENG-implant, LNG-implant and IUD groups, respectively; 995, 997 and 971, respectively, were included in the per protocol analysis reported here. ENG and LNG implants each had the same 3-year cumulative pregnancy rate of 0.4 per 100 W-Y [95% confidence interval (CI) 0.1-1.4]. A weight

  17. Factorial PD-Clustering

    CERN Document Server

    Tortora, Cristina; Summa, Mireille Gettler

    2011-01-01

    Factorial clustering methods have been developed in recent years thanks to the improving of computational power. These methods perform a linear transformation of data and a clustering on transformed data optimizing a common criterion. Factorial PD-clustering is based on Probabilistic Distance clustering (PD-clustering). PD-clustering is an iterative, distribution free, probabilistic, clustering method. Factorial PD-clustering make a linear transformation of original variables into a reduced number of orthogonal ones using a common criterion with PD-Clustering. It is demonstrated that Tucker 3 decomposition allows to obtain this transformation. Factorial PD-clustering makes alternatively a Tucker 3 decomposition and a PD-clustering on transformed data until convergence. This method could significantly improve the algorithm performance and allows to work with large dataset, to improve the stability and the robustness of the method.

  18. Effects of Cluster Size on Platinum-Oxygen Bonds Formation in Small Platinum Clusters

    Science.gov (United States)

    Oemry, Ferensa; Padama, Allan Abraham B.; Kishi, Hirofumi; Kunikata, Shinichi; Nakanishi, Hiroshi; Kasai, Hideaki; Maekawa, Hiroyoshi; Osumi, Kazuo; Sato, Kaoru

    2012-03-01

    We present the results of density functional theory calculation in oxygen dissociative adsorption process on two types of isolated platinum (Pt) clusters: Pt4 and Pt10, by taking into account the effect of cluster reconstruction. The strength of Pt-Pt bonds in the clusters is mainly defined by d-d hybridization and interstitial bonding orbitals (IBO). Oxygen that adsorbed on the clusters is weakening the IBO and thus inducing geometry reconstruction as occurred in Pt10 cluster. However, cluster that could undergo structural deformation is found to promote oxygen dissociation with no energy barrier. The details show that maintaining well-balanced of attractive and repulsive (Hellmann-Feynman) forces between atoms is considered to be the main key to avoid any considerable rise of energy barrier. Furthermore, a modest energy barrier that gained in Pt4 cluster is presumed to be originate from inequality of intramolecular forces between atoms.

  19. Targets for primary prevention: Cultural, social and intrapersonal factors associated with co-occurring health-related behaviours

    NARCIS (Netherlands)

    Dusseldorp, E.; Klein Velderman, M.; Paulussen, T.W.G.M.; Junger, M.; Nieuwenhuijzen, M. van; Reijneveld, S.A.

    2014-01-01

    Objective: Multiple studies have identified clusters of co-occurring health-related behaviours. Little is known, however, about factors associated with such clusters. This study aims to identify these factors and to assess whether their effects are in accordance with the Theory of Triadic Influence

  20. Targets for primary prevention : Cultural, social and intrapersonal factors associated with co-occurring health-related behaviours

    NARCIS (Netherlands)

    Dusseldorp, Elise; Klein Velderman, Mariska; Paulussen, Theo W. G. M.; Junger, Marianne; van Nieuwenhuijzen, Maroesjka; Reijneveld, Sijmen A.

    2014-01-01

    Objective: Multiple studies have identified clusters of co-occurring health-related behaviours. Little is known, however, about factors associated with such clusters. This study aims to identify these factors and to assess whether their effects are in accordance with the Theory of Triadic Influence

  1. Possibilistic Exponential Fuzzy Clustering

    Institute of Scientific and Technical Information of China (English)

    Kiatichai Treerattanapitak; Chuleerat Jaruskulchai

    2013-01-01

    Generally,abnormal points (noise and outliers) cause cluster analysis to produce low accuracy especially in fuzzy clustering.These data not only stay in clusters but also deviate the centroids from their true positions.Traditional fuzzy clustering like Fuzzy C-Means (FCM) always assigns data to all clusters which is not reasonable in some circumstances.By reformulating objective function in exponential equation,the algorithm aggressively selects data into the clusters.However noisy data and outliers cannot be properly handled by clustering process therefore they are forced to be included in a cluster because of a general probabilistic constraint that the sum of the membership degrees across all clusters is one.In order to improve this weakness,possibilistic approach relaxes this condition to improve membership assignment.Nevertheless,possibilistic clustering algorithms generally suffer from coincident clusters because their membership equations ignore the distance to other clusters.Although there are some possibilistic clustering approaches that do not generate coincident clusters,most of them require the right combination of multiple parameters for the algorithms to work.In this paper,we theoretically study Possibilistic Exponential Fuzzy Clustering (PXFCM) that integrates possibilistic approach with exponential fuzzy clustering.PXFCM has only one parameter and not only partitions the data but also filters noisy data or detects them as outliers.The comprehensive experiments show that PXFCM produces high accuracy in both clustering results and outlier detection without generating coincident problems.

  2. Ethical issues occurring within nursing education.

    Science.gov (United States)

    Fowler, Marsha D; Davis, Anne J

    2013-03-01

    The large body of literature labeled "ethics in nursing education" is entirely devoted to curricular matters of ethics education in nursing schools, that is, to what ought to be the ethics content that is taught and what theory or issues ought to be included in all nursing curricula. Where the nursing literature actually focuses on particular ethical issues, it addresses only single topics. Absent from the literature, however, is any systematic analysis and explication of ethical issues or dilemmas that occur within the context of nursing education. The objective of this article is to identify the spectrum of ethical issues in nursing education to the end of prompting a systematic and thorough study of such issues, and to lay the groundwork for research by identifying and provisionally typologizing the ethical issues that occur within the context of academic nursing.

  3. Molten Metal Explosions are Still Occurring

    Science.gov (United States)

    2009-02-01

    pans which can give rise to Force 2 incidents if unheated or contain foreign matter. Handling hot dross represents a particular hazard. Force 3...explosions have occurred from hot dross transfer, cooling and dumping into storage areas. In one recent incident, an employee reportedly dumped a load of...thermiting dross into a water puddle and was fatally burned. Casting: Incidents continue to be reported for dc casting arising from bleed-outs

  4. Structures of Mn clusters

    Indian Academy of Sciences (India)

    Tina M Briere; Marcel H F Sluiter; Vijay Kumar; Yoshiyuki Kawazoe

    2003-01-01

    The geometries of several Mn clusters in the size range Mn13–Mn23 are studied via the generalized gradient approximation to density functional theory. For the 13- and 19-atom clusters, the icosahedral structures are found to be most stable, while for the 15-atom cluster, the bcc structure is more favoured. The clusters show ferrimagnetic spin configurations.

  5. Dissolution of Globular Clusters

    OpenAIRE

    Baumgardt, Holger

    2006-01-01

    Globular clusters are among the oldest objects in galaxies, and understanding the details of their formation and evolution can bring valuable insight into the early history of galaxies. This review summarises the current knowledge about the dissolution of star clusters and discusses the implications of star cluster dissolution for the evolution of the mass function of star cluster systems in galaxies.

  6. Clustering of correlated networks

    OpenAIRE

    Dorogovtsev, S. N.

    2003-01-01

    We obtain the clustering coefficient, the degree-dependent local clustering, and the mean clustering of networks with arbitrary correlations between the degrees of the nearest-neighbor vertices. The resulting formulas allow one to determine the nature of the clustering of a network.

  7. Improvement of functional constipation with kiwifruit intake in a Mediterranean patient population: An open, non-randomized pilot study

    Directory of Open Access Journals (Sweden)

    Oriol Cunillera

    2015-07-01

    Full Text Available Introduction: Kiwifruit consumption has shown to improve functional constipation in healthy elderly population, according to studies in New Zealand and China. The aim of this study was to evaluate the effect of kiwifruit intake on functional constipation in a Mediterranean patient population characterized by its distinctive nutritional habits.Material and Methods: An open, non-controlled and non-randomized longitudinal study was conducted in 46 patients with constipation (Rome III criteria. Patients monitored for five weeks: weeks 1 and 2 no kiwifruit and weeks 3-5 three kiwifruit per day (Green kiwifruit, Actinidia deliciosa var Hayward. Bristol Scale, volume of stools, and ease of defecation was self- reported daily. The evolution of the categorical variables was tested using the Bhapkar test; functional data methodology was used for continuous variables, and Generalized Estimating Equation (GEE models were adjusted.Results: The percentage of patients with ≥3 stools per week increased from 82.61% (95% CI: 69–91.2 at week 1 to 97.78% (95% CI: 87.4–99.9 at week 2 of kiwifruit intake, with 76.09% (95% CI: 61.9–86.2 responding during the first week. The reporting of stable ideal stools increased from 17.39% (95% CI: 8.8–31 at week 2 to 33.33% (95% CI: 21.3–48 at week 5. According to GEE models, the number of depositions increased significantly (p-values<0.001 in 0.398 daily units at week 1 the first week of intake, up to 0.593 daily units at week 5; significant improvements on facility in evacuation and volume of evacuation were found from the firstweek of intake (all p-values<0.001.Conclusions: The intake of three kiwifruits per day significantly improves the quality of evacuation (number of depositions, volume, consistency and ease in a Mediterranean patient population suffering from functional constipation.

  8. Neurotransmitter changes in patients with Parkinson's disease detected by encephalofluctuography technology A non-randomized control study

    Institute of Scientific and Technical Information of China (English)

    Yan Han; Zhenfu Wang; Yang Yang; Xianhong Chen; Hong Sun

    2008-01-01

    BACKGROUND: Encephalofluctuograph Technology (ET) is an advanced and non-traumatic analytical method of brain function. ET can acquire super-slow waves from electroencephalic signals. Studies have shown that these particular spectra can reflect neurochemical processes in the brain. OBJECTIVE: To verify neurotransmitter changes in the brains Parkinson's disease (PD) patients through the use of ET. DESIGN, TIME AND SETTING: A non-randomized concurrent control experiment was performed at the Department of Neurology in Southern Building, General Hospital of Chinese PLA from August to December 2007. PARTICIPANTS: Sixty-one outpatients with PD were selected from the General Hospital of Chinese PLA from August 2007 to December 2007. In addition, 48 healthy subjects were selected as normal controls. METHODS: All patients underwent assessment of the sub scale Ⅱ,Ⅲ, and V of the Unified Parkinson's Disease Rating Scale (UPDRS), in which part Ⅱ was used to inform activity of daily living, part Ⅲ reflected athletic ability, and part Ⅴ was the Hoehn & Yahr grade for symptoms evaluation. Correlation analysis was performed between dopamine levels and UPDRS assessment. Neurotransmitter changes were observed forty-eight prior to and 1.5 hours after medicating with Benserazide. The S1, S2, S4, S5,S7, and S11 spectras respectively reflect gamma-aminobutyric acid (GABA), glutamic acid (Glu), 5-hydroxytryptamine (5-HT), acetylcholine (ACh), norepinephrine, and dopamine. MAIN OUTCOME MEASURES: Neurotransmitter changes in the brains of all subjects, and correlations between dopamine concentrations and UPDRS assessment. Neurotransmitter changes in a subgroup of patients prior to and 1.5 hours after medicating with Benserazide. RESULTS: Concentrations of 5-HT, ACh, and norepinephrine were decreased in the PD group, and GABA was increased. However, there was no significant difference compared with the normal control group (P > 0.05). The level of dopamine in PD group was

  9. Effectiveness of a 'Global Postural Reeducation' program for persistent Low Back Pain: a non-randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Violante Francesco S

    2010-12-01

    Full Text Available Abstract Background The aim of this non-randomized controlled trial was to evaluate the effectiveness of a Global Postural Reeducation (GPR program as compared to a Stabilization Exercise (SE program in subjects with persistent low back pain (LBP at short- and mid-term follow-up (ie. 3 and 6 months. Methods According to inclusion and exclusion criteria, 100 patients with a primary complaint of persistent LBP were enrolled in the study: 50 were allocated to the GPR group and 50 to the SE group. Primary outcome measures were Roland and Morris Disability Questionnaire (RMDQ and Oswestry Disability Index (ODI. Secondary outcome measures were lumbar Visual Analogue Scale (VAS and Fingertip-to-floor test (FFT. Data were collected at baseline and at 3/6 months by health care professionals unaware of the study. An intention to treat approach was used to analyze participants according to the group to which they were originally assigned. Results Of the 100 patients initially included in the study, 78 patients completed the study: 42 in the GPR group and 36 in the SE group. At baseline, the two groups did not differ significantly with respect to gender, age, BMI and outcome measures. Comparing the differences between groups at short- and mid-term follow-up, the GPR group revealed a significant reduction (from baseline in all outcome measures with respect to the SE group. The ordered logistic regression model showed an increased likelihood of definitive improvement (reduction from baseline of at least 30% in RMDQ and VAS scores for the GPR group compared to the SE group (OR 3.9, 95% CI 2.7 to 5.7. Conclusions Our findings suggest that a GPR intervention in subjects with persistent LBP induces a greater improvement on pain and disability as compared to a SE program. These results must be confirmed by further studies with higher methodological standards, including randomization, larger sample size, longer follow-up and subgrouping of the LBP subjects. Trial

  10. Sleep in cluster headache

    DEFF Research Database (Denmark)

    Barloese, M C J; Jennum, P J; Lund, N T

    2015-01-01

    BACKGROUND AND PURPOSE: Cluster headache (CH) is a primary headache disorder characterized by severe attacks of unilateral pain following a chronobiological pattern. There is a close connection with sleep as most attacks occur during sleep. Hypothalamic involvement and a particular association...... with rapid eye movement (REM) sleep have been suggested. Sleep in a large, well-characterized population of CH patients was investigated. METHODS: Polysomnography (PSG) was performed on two nights in 40 CH patients during active bout and one night in 25 age, sex and body mass index matched controls...... in hospital. Macrostructure and other features of sleep were analyzed and related to phenotype. Clinical headache characterization was obtained by semi-structured interview. RESULTS: Ninety-nine nights of PSG were analyzed. Findings included a reduced percentage of REM sleep (17.3% vs. 23.0%, P = 0...

  11. Patterns of white matter damage are non-random and associated with cognitive function in secondary progressive multiple sclerosis

    Directory of Open Access Journals (Sweden)

    K.A. Meijer

    2016-01-01

    Despite the presence of white matter damage, it was possible to reveal patterns of FA covariance across SPMS patients. This could indicate that white matter tracts belonging to the same cluster, and thus with similar characteristics, tend to follow similar trends during neurodegeneration. Furthermore, these underlying FA patterns might help to explain cognitive dysfunction in SPMS.

  12. Contextualizing the Cluster

    DEFF Research Database (Denmark)

    Giacomin, Valeria

    This dissertation examines the case of the palm oil cluster in Malaysia and Indonesia, today one of the largest agricultural clusters in the world. My analysis focuses on the evolution of the cluster from the 1880s to the 1970s in order to understand how it helped these two countries to integrate......-researched topic in the cluster literature – the emergence of clusters, their governance and institutional change, and competition between rival cluster locations – through the case of the Southeast Asian palm oil cluster....

  13. Contextualizing the Cluster

    DEFF Research Database (Denmark)

    Giacomin, Valeria

    This dissertation examines the case of the palm oil cluster in Malaysia and Indonesia, today one of the largest agricultural clusters in the world. My analysis focuses on the evolution of the cluster from the 1880s to the 1970s in order to understand how it helped these two countries to integrate......-researched topic in the cluster literature – the emergence of clusters, their governance and institutional change, and competition between rival cluster locations – through the case of the Southeast Asian palm oil cluster....

  14. Clustering in analytical chemistry.

    Science.gov (United States)

    Drab, Klaudia; Daszykowski, Michal

    2014-01-01

    Data clustering plays an important role in the exploratory analysis of analytical data, and the use of clustering methods has been acknowledged in different fields of science. In this paper, principles of data clustering are presented with a direct focus on clustering of analytical data. The role of the clustering process in the analytical workflow is underlined, and its potential impact on the analytical workflow is emphasized.

  15. Genetic and molecular dissection of naturally occurring variations in rice

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Masahiro [National Institute of Agrobiological Sciences, Tsukuba, Ibaraki (Japan)

    2002-02-01

    The progress for structural analysis of the rice genome has allowed us to embark on the sequencing of the whole rice genome. Resources - genetic markers, sequence data, and genomic clones - derived from many efforts will be used for the functional analysis of rice genes in the next decade. Although artificially induced variations, such as mutants, have been used mainly for genetic and physiological studies in rice and other plant species, the development of DNA markers has made possible access to naturally occurring allelic variations underlying complex traits. Such analysis is often referred to as quantitative traits locus (QTL) analysis. Many QTLs have been mapped for many complex traits in rice. During the analyses of several quantitative traits by the DNA marker-assisted strategy, two questions about QTL analysis have been raised: 1) Does a QTL represent a single Mendelian locus or a cluster of multiple loci? 2) Is it possible to precisely map a QTL and identify QTLs at the molecular level using map-based or other strategies? To answer these questions, a series of analyses on heading date, including the identification of putative QTLs, characterization and fine mapping of QTLs using nearly isogenic lines (NILs), and identification of genes at QTLs for heading date by the map-based strategy has been performed. In addition, several primary permanent mapping populations and secondary genetic resources, such as chromosomal segmental substitution lines, have been developed to facilitate the genetic analysis of naturally occurring allelic variation. (M. Suetake)

  16. Naturally occurring radionuclides and Earth sciences

    Directory of Open Access Journals (Sweden)

    G. Ferrara

    1997-06-01

    Full Text Available Naturally occurring radionuclides are used in Earth sciences for two fundamental purposes: age determination of rocks and minerals and studies of variation of the isotopic composition of radiogenic nuclides. The methodologies that are in use today allow us to determine ages spanning from the Earth's age to the late Quaternary. The variations of isotopic composition of radiogenic nuclides can be applied to problems of mantle evolution, magma genesis and characterization with respect to different geodynamic situations and can provide valuable information not obtainable by elemental geochemistry.

  17. A network of cancer genes with co-occurring and anti-co-occurring mutations.

    Directory of Open Access Journals (Sweden)

    Qinghua Cui

    Full Text Available Certain cancer genes contribute to tumorigenesis in a manner of either co-occurring or mutually exclusive (anti-co-occurring mutations; however, the global picture of when, where and how these functional interactions occur remains unclear. This study presents a systems biology approach for this purpose. After applying this method to cancer gene mutation data generated from large-scale and whole genome sequencing of cancer samples, a network of cancer genes with co-occurring and anti-co-occurring mutations was constructed. Analysis of this network revealed that genes with co-occurring mutations prefer direct signaling transductions and that the interaction relations among cancer genes in the network are related with their functional similarity. It was also revealed that genes with co-occurring mutations tend to have similar mutation frequencies, whereas genes with anti-co-occurring mutations tend to have different mutation frequencies. Moreover, genes with more exons tend to have more co-occurring mutations with other genes, and genes having lower local coherent network structures tend to have higher mutation frequency. The network showed two complementary modules that have distinct functions and have different roles in tumorigenesis. This study presented a framework for the analysis of cancer genome sequencing outputs. The presented data and uncovered patterns are helpful for understanding the contribution of gene mutations to tumorigenesis and valuable in the identification of key biomarkers and drug targets for cancer.

  18. INTERRUPTED STELLAR ENCOUNTERS IN STAR CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Geller, Aaron M. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Leigh, Nathan W. C., E-mail: a-geller@northwestern.edu, E-mail: nleigh@amnh.org [Department of Astrophysics, American Museum of Natural History, Central Park West and 79th Street, New York, NY 10024 (United States)

    2015-07-20

    Strong encounters between single stars and binaries play a pivotal role in the evolution of star clusters. Such encounters can also dramatically modify the orbital parameters of binaries, exchange partners in and out of binaries, and are a primary contributor to the rate of physical stellar collisions in star clusters. Often, these encounters are studied under the approximation that they happen quickly enough and within a small enough volume to be considered isolated from the rest of the cluster. In this paper, we study the validity of this assumption through the analysis of a large grid of single–binary and binary–binary scattering experiments. For each encounter we evaluate the encounter duration, and compare this with the expected time until another single or binary star will join the encounter. We find that for lower-mass clusters, similar to typical open clusters in our Galaxy, the percent of encounters that will be “interrupted” by an interloping star or binary may be 20%–40% (or higher) in the core, though for typical globular clusters we expect ≲1% of encounters to be interrupted. Thus, the assumption that strong encounters occur in relative isolation breaks down for certain clusters. Instead, many strong encounters develop into more complex “mini-clusters,” which must be accounted for in studying, for example, the internal dynamics of star clusters, and the physical stellar collision rate.

  19. The down-stress transition from cluster to cone fabrics in experimentally deformed ice

    Science.gov (United States)

    Qi, Chao; Goldsby, David L.; Prior, David J.

    2017-08-01

    During plastic deformation of polycrystalline ice 1h, ice crystals become crystallographically aligned due to dislocation glide, primarily on the basal slip system. Such crystallographic preferred orientation (CPO) introduces a viscous anisotropy in ice, and thus strongly influences the kinematics of the flow of glaciers and ice sheets. Two key mechanisms exert different controls on CPO. In axial compression, recrystallization dominated by lattice rotation yields a cluster of c-axes parallel to compression, and recrystallization dominated by grain boundary migration (GBM) yields a cone-shaped distribution of c-axes with the cone axis parallel to compression. The transition between these dominant mechanisms of CPO formation has not been well quantified. In this study, we explore how this transition varies with stress. Ice deformation experiments were conducted using a high-pressure, gas-medium apparatus to prevent fracturing of samples at relatively high stresses. Samples were deformed in uniaxial compression at a temperature of ∼-10 °C and a confining pressure of 10 MPa. Fabricated ice samples with starting average grain sizes of either ∼0.23 mm or ∼0.63 mm were each deformed to an axial strain of ∼0.2 at a nominally constant strain rate in the range 1.2 ×10-6 to 2.4 ×10-4 s-1, yielding flow stresses of 1.17 to 4.31 MPa. High-quality electron backscatter diffraction reveal the grain size, shape, subgrain structure, and CPOs formed at different stresses. All deformed samples have strong, non-random CPOs with c-axes concentrated in cones. The cone angle and CPO strength are observed to decrease with increasing stress. As stress increases, the fraction of grains with highly curved or lobate grain boundaries decreases and the fraction of polygonal grains with straight grain boundaries increases. Based on these observations, we propose that a transition in the dominant mechanism of CPO formation occurs with increasing stress, from GBM, which consumes grains

  20. Evolutionary liberties of the Abutilon mosaic virus cluster.

    Science.gov (United States)

    Fischer, Alexander; Strohmeier, Stephan; Krenz, Björn; Jeske, Holger

    2015-02-01

    Two new strains of Abutilon mosaic virus (AbMV; Geminiviridae) from Germany (Stuttgart) and France (Paris) have been characterized by circomics, direct pyrosequencing of rolling circle amplification (RCA) products, as well as conventional cloning and Sanger sequencing. RCA combined with an analysis of restriction fragment length polymorphisms confirmed the completeness of the sequence determination and a close relationship of both isolates for DNA A with 99 % nucleotide sequence identity. Phylogenetic tree reconstruction supported their clustering with other AbMV strains in a clade with Middle American begomoviruses, whereas South American begomoviruses that infect Abutilon or Sida micrantha are less closely related. Comparing the coat protein (CP) genes of the AbMV cluster, with those of related Middle and South American begomoviruses revealed a remarkable overrepresentation for non-synonymous nucleotide exchanges for certain amino acid positions in the AbMV cluster. Projection of these positions to a structural model of the African cassava mosaic virus CP yielded a non-random distribution at the periphery and, most importantly, highlighted those amino acids that had been identified in whitefly-transmission experiments before. These results establish the basis for an analysis of the evolutionary liberty of certain amino acid positions of the CP, and their impact on the deciphering of insect transmission determinants is discussed.

  1. Tetrahydroberberine, a pharmacologically active naturally occurring alkaloid.

    Science.gov (United States)

    Pingali, Subramanya; Donahue, James P; Payton-Stewart, Florastina

    2015-04-01

    Tetrahydroberberine (systematic name: 9,10-dimethoxy-5,8,13,13a-tetrahydro-6H-benzo[g][1,3]benzodioxolo[5,6-a]quinolizine), C20H21NO4, a widely distributed naturally occurring alkaloid, has been crystallized as a racemic mixture about an inversion center. A bent conformation of the molecule is observed, with an angle of 24.72 (5)° between the arene rings at the two ends of the reduced quinolizinium core. The intermolecular hydrogen bonds that play an apparent role in crystal packing are 1,3-benzodioxole -CH2···OCH3 and -OCH3···OCH3 interactions between neighboring molecules.

  2. Pilomyxoid Astrocytoma Occurring in the Third Ventricle

    Directory of Open Access Journals (Sweden)

    Sanghyeon Kim

    2015-01-01

    Full Text Available Pilomyxoid astrocytoma (PMA is a rare central nervous system tumor that has been included in the 2007 World Health Organization Classification of Tumors of the Central Nervous System. Due to its more aggressive behavior, PMA is classified as Grade II neoplasm by the World Health Organization. PMA predominantly affects the hypothalamic/chiasmatic region and occurs in children (mean age of occurrence = 10 months. We report a case of a 24-year-old man who presented with headache, nausea, and vomiting. Brain CT and MRI revealed a mass occupying only the third ventricle. We performed partial resection. Histological findings, including monophasic growth with a myxoid background, and absence of Rosenthal fibers or eosinophilic granular bodies, as well as the strong positivity for glial fibrillary acidic protein were consistent with PMA.

  3. Detection of Harmonic Occurring using Kalman Filtering

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar; Shoro, Ghulam Mustafa; Imran, Raja Muhammed

    2014-01-01

    As long as the load to a power system is linear which has been the case before 80's, typically no harmonics are produced. However, the modern power electronic equipment for controlled power consumption produces harmonic disturbances, these devices/equipment possess nonlinear voltage/current chara...... using Kalman filter. This may be very useful for example to quickly switching on certain filters based on the harmonic present. We are using a unique technique to detect the occurrence of harmonics......./current characteristic. These harmonics are not to be allowed to grow beyond a certain limit to avoid any grave consequence to the customer’s main supply. Filters can be implemented at the power source or utility location to eliminate these harmonics. In this paper we detect the instance at which these harmonics occur...

  4. Amine reactivity with charged sulfuric acid clusters

    Science.gov (United States)

    Bzdek, B. R.; Ridge, D. P.; Johnston, M. V.

    2011-08-01

    The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge), both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4)(H2SO4)x]- and [(NH4)x(HSO4)x+1(H2SO4)3]-. Dimethylamine substitution for ammonia in [(NH4) x(HSO4) x+1(H2SO4)3]- clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4) (H2SO4) x]- clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400), whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2-3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition. Therefore, in locations where amine levels are within a few orders of magnitude of ammonia levels, amine chemistry may compete favorably with ammonia chemistry.

  5. What Makes Clusters Decline?

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter; Park, Eun Kyung

    2015-01-01

    Most studies on regional clusters focus on identifying factors and processes that make clusters grow. However, sometimes technologies and market conditions suddenly shift, and clusters decline. This paper analyses the process of decline of the wireless communication cluster in Denmark....... The longitudinal study on the high-tech cluster reveals that technological lock-in and exit of key firms have contributed to decline. Entrepreneurship has a positive effect on the cluster’s adaptive capabilities, while multinational companies have contradicting effects by bringing in new resources to the cluster...

  6. Insulin resistance and occurrence and prognosis of ischemic stroke A non-randomized concurrent control and intra-group comparison

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Zhao; Shaojun Jiang; Yue Tan

    2008-01-01

    BACKGROUND: Clinical evidence has demonstrated that insulin resistance might be an independent risk factor for ischemic stroke, which has not been recognized. At present, insulin resistance has been proven to be an independent risk factor for coronary arteriosclerotic heart disease. However, the relationship between the onset and prognosis of ischemic stroke remains unclear. OBJECTIVE: This study was designed to analyze the relationship between insulin resistance and ischemic stroke and the correlation between insulin resistance and stroke risk factor, and to investigate the relationship between insulin resistance and ischemic stroke prognosis as well as whether insulin resistance is an independent prognostic factor. DESIGN: A non-randomized concurrent control experiment. SETTING: Department of Geriatric Disease, Second Affiliated Hospital of Kunming Medical College. PARTICIPANTS: A total of 106 inpatients with ischemic stroke of the cervical internal carotid artery, who had suffered from the disease within the previous 72 hours, were admitted to the Department of Neurology, First Affiliated Hospital of Kunming Medical College from March to December in 2005 and, recruited for the present study. All 106 inpatients corresponded to the diagnostic criteria of ischemic stroke, formulated at the Fourth National Cerebrovascular Disease Conference in 1995, and were confirmed as having had an ischemic stroke by CT/MRI examinations. The patient group consisted of 54 males and 52 females. An additional 50 healthy individuals, who received health examinations simultaneously, were included as controls. Among the control subjects, there were 26 males and 24 females. Informed consent for laboratory measurements was obtained from all subjects; this study was approved by the Hospital Ethics Committee.METHODS: Following admission, all subjects were inquired of age, gender, previous history, blood pressure, body temperature, admission time, and smoking habits. Meanwhile, they were

  7. Clusters of suicides and suicide attempts: detection, proximity and correlates.

    Science.gov (United States)

    Too, L S; Pirkis, J; Milner, A; Spittal, M J

    2017-10-01

    A suicide cluster is defined as a higher number of observed cases occurring in space and/or time than would typically be expected. Previous research has largely focused on identifying clusters of suicides, while there has been comparatively limited research on clusters of suicide attempts. We sought to identify clusters of both types of behaviour, and having done that, identify the factors that distinguish suicide attempts inside a cluster from those that were outside a cluster. We used data from Western Australia from 2000 to 2011. We defined suicide attempts as admissions to hospital for deliberate self-harm and suicides as deaths due to deliberate self-harm. Using an analytic strategy that accounted for the repetition of attempted suicide within a cluster, we performed spatial-temporal analysis using Poisson discrete scan statistics to detect clusters of suicide attempts and clusters of suicides. Logistic regression was then used to compare clustered attempts with non-clustered attempts to identify risk factors for an attempt being in a cluster. We detected 350 (1%) suicide attempts occurring within seven spatial-temporal clusters and 12 (0.6%) suicides occurring within two spatial-temporal clusters. Both of the suicide clusters were located within a larger but later suicide attempt cluster. In multivariate analysis, suicide attempts by individuals who lived in areas of low socioeconomic status had higher odds of being in a cluster than those living in areas of high socioeconomic status [odds ratio (OR) = 29.1, 95% confidence interval (CI) = 6.3-135.5]. A one percentage-point increase in the proportion of people who had changed address in the last year was associated with a 60% increase in the odds of the attempt being within a cluster (OR = 1.60, 95% CI = 1.29-1.98) and a one percentage-point increase in the proportion of Indigenous people in the area was associated with a 7% increase in the suicide being within a cluster (OR = 1.07, 95% CI = 1.00-1.13). Age

  8. The origin and evolution of cluster magnetism

    CERN Document Server

    Shukurov, A; Haugen, N E L

    2006-01-01

    Random motions can occur in the intergalactic gas of galaxy clusters at all stages of their evolution. Depending on the poorly known value of the Reynolds number, these motions can or cannot become turbulent, but in any case they can generate random magnetic fields via dynamo action. We argue that magnetic fields inferred observationally for the intracluster medium require dynamo action, and then estimate parameters of random flows and magnetic fields at various stages of the cluster evolution.

  9. Star cluster ecology IVa Dissection of an open star cluster-photometry

    CERN Document Server

    Zwart, S F P; Hut, P; Makino, J; Zwart, Simon F. Portegies; Millan, Stephen L. W. Mc; Hut, Piet; Makino, Junichiro

    2000-01-01

    The evolution of star clusters is studied using N-body simulations in which the evolution of single stars and binaries are taken self-consistently into account. Initial conditions are chosen to represent relatively young Galactic open clusters, such as the Pleiades, Praesepe and the Hyades. The calculations include a realistic mass function, primordial binaries and the external potential of the parent Galaxy. Our model clusters are generally significantly flattened in the Galactic tidal field, and dissolve before deep core collapse occurs. The binary fraction decreases initially due to the destruction of soft binaries, but increases later because lower mass single stars escape more easily than the more massive binaries. At late times, the cluster core is quite rich in giants and white dwarfs. There is no evidence for preferential evaporation of old white dwarfs, on the contrary the formed white dwarfs are likely to remain in the cluster. Stars tend to escape from the cluster through the first and second Lagra...

  10. Comprehensive cluster analysis with Transitivity Clustering.

    Science.gov (United States)

    Wittkop, Tobias; Emig, Dorothea; Truss, Anke; Albrecht, Mario; Böcker, Sebastian; Baumbach, Jan

    2011-03-01

    Transitivity Clustering is a method for the partitioning of biological data into groups of similar objects, such as genes, for instance. It provides integrated access to various functions addressing each step of a typical cluster analysis. To facilitate this, Transitivity Clustering is accessible online and offers three user-friendly interfaces: a powerful stand-alone version, a web interface, and a collection of Cytoscape plug-ins. In this paper, we describe three major workflows: (i) protein (super)family detection with Cytoscape, (ii) protein homology detection with incomplete gold standards and (iii) clustering of gene expression data. This protocol guides the user through the most important features of Transitivity Clustering and takes ∼1 h to complete.

  11. Introduction to naturally occurring radioactive material

    Energy Technology Data Exchange (ETDEWEB)

    Egidi, P.

    1997-08-01

    Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels of radiation and radioactivity. But some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Other activities, such as flying at high altitudes, expose us to elevated levels of NORM. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose

  12. Introduction to naturally occurring radioactive material

    Energy Technology Data Exchange (ETDEWEB)

    Egidi, P.

    1997-08-01

    Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels of radiation and radioactivity. But some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Other activities, such as flying at high altitudes, expose us to elevated levels of NORM. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose

  13. Clustering-based classification of road traffic accidents using hierarchical clustering and artificial neural networks.

    Science.gov (United States)

    Taamneh, Madhar; Taamneh, Salah; Alkheder, Sharaf

    2017-09-01

    Artificial neural networks (ANNs) have been widely used in predicting the severity of road traffic crashes. All available information about previously occurred accidents is typically used for building a single prediction model (i.e., classifier). Too little attention has been paid to the differences between these accidents, leading, in most cases, to build less accurate predictors. Hierarchical clustering is a well-known clustering method that seeks to group data by creating a hierarchy of clusters. Using hierarchical clustering and ANNs, a clustering-based classification approach for predicting the injury severity of road traffic accidents was proposed. About 6000 road accidents occurred over a six-year period from 2008 to 2013 in Abu Dhabi were used throughout this study. In order to reduce the amount of variation in data, hierarchical clustering was applied on the data set to organize it into six different forms, each with different number of clusters (i.e., clusters from 1 to 6). Two ANN models were subsequently built for each cluster of accidents in each generated form. The first model was built and validated using all accidents (training set), whereas only 66% of the accidents were used to build the second model, and the remaining 34% were used to test it (percentage split). Finally, the weighted average accuracy was computed for each type of models in each from of data. The results show that when testing the models using the training set, clustering prior to classification achieves (11%-16%) more accuracy than without using clustering, while the percentage split achieves (2%-5%) more accuracy. The results also suggest that partitioning the accidents into six clusters achieves the best accuracy if both types of models are taken into account.

  14. The Cluster Substructure - Alignment Connection

    OpenAIRE

    Plionis, Manolis

    2001-01-01

    Using the APM cluster data we investigate whether the dynamical status of clusters is related to the large-scale structure of the Universe. We find that cluster substructure is strongly correlated with the tendency of clusters to be aligned with their nearest neighbour and in general with the nearby clusters that belong to the same supercluster. Furthermore, dynamically young clusters are more clustered than the overall cluster population. These are strong indications that cluster develop in ...

  15. Nuclear Clusters in Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, H.; Kahl, D.; Wakabayashi, Y.; Yamaguchi, H. [Center for Nuclear Study (CNS), University of Tokyo, Wako Branch at RIKEN 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Teranishi, T. [Department of Physics, Kyushu University, Fukuoka, 812-8581 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan); Komatsubara, T. [Department of Physics, Tsukuba University, Ibaraki, 305-8571 (Japan); Kato, S. [Department of Physics, Yamagata University, Yamagata, 990-8560 (Japan); Khiem, Le H. [Institute of Physics, Vietnam Academy for Science and Technology, Hanoi (Viet Nam)

    2010-03-01

    The role of nuclear clustering is discussed for nucleosynthesis in stellar evolution with Cluster Nucleosynthesis Diagram (CND) proposed before. Special emphasis is placed on alpha-induced stellar reactions together with molecular states for O and C burning.

  16. [Pathophysiology of cluster headache].

    Science.gov (United States)

    Donnet, Anne

    2015-11-01

    The aetiology of cluster headache is partially unknown. Three areas are involved in the pathogenesis of cluster headache: the trigeminal nociceptive pathways, the autonomic system and the hypothalamus. The cluster headache attack involves activation of the trigeminal autonomic reflex. A dysfunction located in posterior hypothalamic gray matter is probably pivotal in the process. There is a probable association between smoke exposure, a possible genetic predisposition and the development of cluster headache.

  17. Cluster Physics with Merging Galaxy Clusters

    Directory of Open Access Journals (Sweden)

    Sandor M. Molnar

    2016-02-01

    Full Text Available Collisions between galaxy clusters provide a unique opportunity to study matter in a parameter space which cannot be explored in our laboratories on Earth. In the standard LCDM model, where the total density is dominated by the cosmological constant ($Lambda$ and the matter density by cold dark matter (CDM, structure formation is hierarchical, and clusters grow mostly by merging.Mergers of two massive clusters are the most energetic events in the universe after the Big Bang,hence they provide a unique laboratory to study cluster physics.The two main mass components in clusters behave differently during collisions:the dark matter is nearly collisionless, responding only to gravity, while the gas is subject to pressure forces and dissipation, and shocks and turbulenceare developed during collisions. In the present contribution we review the different methods used to derive the physical properties of merging clusters. Different physical processes leave their signatures on different wavelengths, thusour review is based on a multifrequency analysis. In principle, the best way to analyze multifrequency observations of merging clustersis to model them using N-body/HYDRO numerical simulations. We discuss the results of such detailed analyses.New high spatial and spectral resolution ground and space based telescopeswill come online in the near future. Motivated by these new opportunities,we briefly discuss methods which will be feasible in the near future in studying merging clusters.

  18. The Durban Auto Cluster

    DEFF Research Database (Denmark)

    Lorentzen, Jochen; Robbins, Glen; Barnes, Justin

    2004-01-01

    The paper describes the formation of the Durban Auto Cluster in the context of trade liberalization. It argues that the improvement of operational competitiveness of firms in the cluster is prominently due to joint action. It tests this proposition by comparing the gains from cluster activities i...

  19. The Durban Auto Cluster

    DEFF Research Database (Denmark)

    Lorentzen, Jochen; Robbins, Glen; Barnes, Justin

    2004-01-01

    The paper describes the formation of the Durban Auto Cluster in the context of trade liberalization. It argues that the improvement of operational competitiveness of firms in the cluster is prominently due to joint action. It tests this proposition by comparing the gains from cluster activities i...

  20. Marketing research cluster analysis

    Directory of Open Access Journals (Sweden)

    Marić Nebojša

    2002-01-01

    Full Text Available One area of applications of cluster analysis in marketing is identification of groups of cities and towns with similar demographic profiles. This paper considers main aspects of cluster analysis by an example of clustering 12 cities with the use of Minitab software.

  1. Cluster Correspondence Analysis

    NARCIS (Netherlands)

    M. van de Velden (Michel); A. Iodice D' Enza; F. Palumbo

    2014-01-01

    markdownabstract__Abstract__ A new method is proposed that combines dimension reduction and cluster analysis for categorical data. A least-squares objective function is formulated that approximates the cluster by variables cross-tabulation. Individual observations are assigned to clusters

  2. Assembly bias and splashback in galaxy clusters

    Science.gov (United States)

    Busch, Philipp; White, Simon D. M.

    2017-10-01

    We use publicly available data for the Millennium Simulation to explore the implications of the recent detection of assembly bias and splashback signatures in a large sample of galaxy clusters. These were identified in the Sloan Digital Sky Survey/Data Release 8 (SDSS/DR8) photometric data by the redMaPPer algorithm and split into high- and low-concentration subsamples based on the projected positions of cluster members. We use simplified versions of these procedures to build cluster samples of similar size from the simulation data. These match the observed samples quite well and show similar assembly bias and splashback signals. Previous theoretical work has found the logarithmic slope of halo density profiles to have a well-defined minimum whose depth decreases and whose radius increases with halo concentration. Projected profiles for the observed and simulated cluster samples show trends with concentration which are opposite to these predictions. In addition, for high-concentration clusters the minimum slope occurs at significantly smaller radius than predicted. We show that these discrepancies all reflect confusion between splashback features and features imposed on the profiles by the cluster identification and concentration estimation procedures. The strong apparent assembly bias is not reflected in the three-dimensional distribution of matter around clusters. Rather it is a consequence of the preferential contamination of low-concentration clusters by foreground or background groups.

  3. Information Needs While A Disaster Is Occurring

    Science.gov (United States)

    Perry, S. C.

    2010-12-01

    that rainfall intensity at their homes might be less than the intensity up in the mountains where the debris flows would start. Nor did they know that debris flows travel too quickly to be outrun. These and many other examples indicate need for social and natural scientists to increase awareness of what to expect when the disaster strikes. This information must be solidly understood before the event occurs - while a disaster is unfolding there are no teachable moments. Case studies indicate that even those who come into a disaster well educated about the phenomenon can struggle to apply what they know when the real situation is at hand. In addition, psychological studies confirm diminished ability to comprehend information at times of stress.

  4. Cluster Evolution in Undercooled Melt and Solidification of Undercooled Ge-based Alloy Melts Induced by Extrinsic Clusters

    Institute of Scientific and Technical Information of China (English)

    王煦; 景勤; 王文魁

    2003-01-01

    The structure or short-range order of clusters in undercooled metallic melts is influenced, to some extent, by the interfacial free energy between the cluster and the melt. Analyses of the effects of interfacial energy on the cluster structure based on the Gibbs equation show a possibility that atoms in the clusters tend to be packed more loosely with the increasing cluster size (or the undercooling). Nucleation may occur, following these analyses,when clusters reach a definite size and atoms in the clusters relax to some extent to form the crystal structure.Indirect support to this viewpoint is provided by the present results of cluster-induced nucleation experiments on undercooled Ge73.7Ni26.3 alloy melts.

  5. Cluster analysis for applications

    CERN Document Server

    Anderberg, Michael R

    1973-01-01

    Cluster Analysis for Applications deals with methods and various applications of cluster analysis. Topics covered range from variables and scales to measures of association among variables and among data units. Conceptual problems in cluster analysis are discussed, along with hierarchical and non-hierarchical clustering methods. The necessary elements of data analysis, statistics, cluster analysis, and computer implementation are integrated vertically to cover the complete path from raw data to a finished analysis.Comprised of 10 chapters, this book begins with an introduction to the subject o

  6. Range-Clustering Queries

    OpenAIRE

    Abrahamsen, Mikkel; de Berg, Mark; Buchin, Kevin; Mehr, Mehran; Mehrabi, Ali D.

    2017-01-01

    In a geometric $k$-clustering problem the goal is to partition a set of points in $\\mathbb{R}^d$ into $k$ subsets such that a certain cost function of the clustering is minimized. We present data structures for orthogonal range-clustering queries on a point set $S$: given a query box $Q$ and an integer $k>2$, compute an optimal $k$-clustering for $S\\setminus Q$. We obtain the following results. We present a general method to compute a $(1+\\epsilon)$-approximation to a range-clustering query, ...

  7. Cluster Decline and Resilience

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter; Park, Eun Kyung

    -2011. Our longitudinal study reveals that technological lock-in and exit of key firms have contributed to impairment of the cluster’s resilience in adapting to disruptions. Entrepreneurship has a positive effect on cluster resilience, while multinational companies have contradicting effects by bringing......Most studies on regional clusters focus on identifying factors and processes that make clusters grow. However, sometimes technologies and market conditions suddenly shift, and clusters decline. This paper analyses the process of decline of the wireless communication cluster in Denmark, 1963...

  8. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  9. Spatial cluster modelling

    CERN Document Server

    Lawson, Andrew B

    2002-01-01

    Research has generated a number of advances in methods for spatial cluster modelling in recent years, particularly in the area of Bayesian cluster modelling. Along with these advances has come an explosion of interest in the potential applications of this work, especially in epidemiology and genome research. In one integrated volume, this book reviews the state-of-the-art in spatial clustering and spatial cluster modelling, bringing together research and applications previously scattered throughout the literature. It begins with an overview of the field, then presents a series of chapters that illuminate the nature and purpose of cluster modelling within different application areas, including astrophysics, epidemiology, ecology, and imaging. The focus then shifts to methods, with discussions on point and object process modelling, perfect sampling of cluster processes, partitioning in space and space-time, spatial and spatio-temporal process modelling, nonparametric methods for clustering, and spatio-temporal ...

  10. Unconventional methods for clustering

    Science.gov (United States)

    Kotyrba, Martin

    2016-06-01

    Cluster analysis or clustering is a task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). It is the main task of exploratory data mining and a common technique for statistical data analysis used in many fields, including machine learning, pattern recognition, image analysis, information retrieval, and bioinformatics. The topic of this paper is one of the modern methods of clustering namely SOM (Self Organising Map). The paper describes the theory needed to understand the principle of clustering and descriptions of algorithm used with clustering in our experiments.

  11. CLEAN: CLustering Enrichment ANalysis

    Directory of Open Access Journals (Sweden)

    Medvedovic Mario

    2009-07-01

    Full Text Available Abstract Background Integration of biological knowledge encoded in various lists of functionally related genes has become one of the most important aspects of analyzing genome-wide functional genomics data. In the context of cluster analysis, functional coherence of clusters established through such analyses have been used to identify biologically meaningful clusters, compare clustering algorithms and identify biological pathways associated with the biological process under investigation. Results We developed a computational framework for analytically and visually integrating knowledge-based functional categories with the cluster analysis of genomics data. The framework is based on the simple, conceptually appealing, and biologically interpretable gene-specific functional coherence score (CLEAN score. The score is derived by correlating the clustering structure as a whole with functional categories of interest. We directly demonstrate that integrating biological knowledge in this way improves the reproducibility of conclusions derived from cluster analysis. The CLEAN score differentiates between the levels of functional coherence for genes within the same cluster based on their membership in enriched functional categories. We show that this aspect results in higher reproducibility across independent datasets and produces more informative genes for distinguishing different sample types than the scores based on the traditional cluster-wide analysis. We also demonstrate the utility of the CLEAN framework in comparing clusterings produced by different algorithms. CLEAN was implemented as an add-on R package and can be downloaded at http://Clusteranalysis.org. The package integrates routines for calculating gene specific functional coherence scores and the open source interactive Java-based viewer Functional TreeView (FTreeView. Conclusion Our results indicate that using the gene-specific functional coherence score improves the reproducibility of the

  12. Survey on Text Document Clustering

    OpenAIRE

    M.Thangamani; Dr.P.Thangaraj

    2010-01-01

    Document clustering is also referred as text clustering, and its concept is merely equal to data clustering. It is hardly difficult to find the selective information from an ‘N’number of series information, so that document clustering came into picture. Basically cluster means a group of similar data, document clustering means segregating the data into different groups of similar data. Clustering can be of mathematical, statistical or numerical domain. Clustering is a fundamental data analysi...

  13. Vitamin D status and weight loss: a systematic review and meta-analysis of randomized and nonrandomized controlled weight-loss trials.

    Science.gov (United States)

    Mallard, Simonette R; Howe, Anna S; Houghton, Lisa A

    2016-10-01

    Obesity is associated with lower concentrations of serum 25-hydroxyvitamin D; however, uncertainty exists as to the direction of causation. To date, meta-analyses of randomized controlled vitamin D-supplementation trials have shown no effect of raising circulating vitamin D on body weight, although several weight-loss-intervention trials have reported an increase in circulating vitamin D after weight reduction. We undertook a systematic review and meta-analysis of randomized and nonrandomized controlled trials to determine whether weight loss compared with weight maintenance leads to an increase in serum 25-hydroxyvitamin D. A systematic search for controlled weight-loss-intervention studies published up to 31 March 2016 was performed. Studies that included participants of any age with changes in adiposity and serum 25-hydroxyvitamin D as primary or secondary outcomes were considered eligible. We identified 4 randomized controlled trials (n = 2554) and 11 nonrandomized controlled trials (n = 917) for inclusion in the meta-analysis. Random assignment to weight loss compared with weight maintenance resulted in a greater increase in serum 25-hydroxyvitamin D with a mean difference of 3.11 nmol/L (95% CI: 1.38, 4.84 nmol/L) between groups, whereas a mean difference of 4.85 nmol/L (95% CI: 2.59, 7.12 nmol/L) was observed in nonrandomized trials. No evidence for a dose-response effect of weight loss on the change in serum 25-hydroxyvitamin D was shown overall. Our results indicate that vitamin D status may be marginally improved with weight loss in comparison with weight maintenance under similar conditions of supplemental vitamin D intake. Although additional studies in unsupplemented individuals are needed to confirm these findings, our results support the view that the association between obesity and lower serum 25-hydroxyvitamin D may be due to reversed causation with increased adiposity leading to suboptimal concentrations of circulating vitamin D. This trial was

  14. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and

  15. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and mea

  16. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and mea

  17. Variations of X chromosome inactivation occur in early passages of female human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Tamar Dvash

    Full Text Available X chromosome inactivation (XCI is a dosage compensation mechanism essential for embryonic development and cell physiology. Human embryonic stem cells (hESCs derived from inner cell mass (ICM of blastocyst stage embryos have been used as a model system to understand XCI initiation and maintenance. Previous studies of undifferentiated female hESCs at intermediate passages have shown three possible states of XCI; 1 cells in a pre-XCI state, 2 cells that already exhibit XCI, or 3 cells that never undergo XCI even upon differentiation. In this study, XCI status was assayed in ten female hESC lines between passage 5 and 15 to determine whether XCI variations occur in early passages of hESCs. Our results show that three different states of XCI already exist in the early passages of hESC. In addition, we observe one cell line with skewed XCI and preferential expression of X-linked genes from the paternal allele, while another cell line exhibits random XCI. Skewed XCI in undifferentiated hESCs may be due to clonal selection in culture instead of non-random XCI in ICM cells. We also found that XIST promoter methylation is correlated with silencing of XIST transcripts in early passages of hESCs, even in the pre-XCI state. In conclusion, XCI variations already take place in early passages of hESCs, which may be a consequence of in vitro culture selection during the derivation process. Nevertheless, we cannot rule out the possibility that XCI variations in hESCs may reflect heterogeneous XCI states in ICM cells that stochastically give rise to hESCs.

  18. Two new polyoxovanadate clusters templated through cysteamine

    Indian Academy of Sciences (India)

    K Pavani; S Upreti; A Ramanan

    2006-03-01

    Two new fully oxidized polyoxovanadate cluster-based solids (C4N2S2H14)2[H2V10O28]$\\cdot$4H2O, 1 and (C4N2S2H14)5[H4V15O42]2.10H2O, 2 are crystallized under self-assembly process in the presence of cysteamine. In both 1 and 2, cysteamines are oxidized forming disulphide linkages and occur as counter cations. The organic cations assemble around V10O28 cluster anions in 1 whereas they aggregate around V15O42 clusters in 2. pH appears to be the structure determinant in the occurrence of decavanadate cluster in 1 and pentadecavanadate in 2, with the same counter cation.

  19. Coagulation of carbon clusters in detonation front

    Science.gov (United States)

    Kupershtokh, A. L.; Ershov, A. P.; Medvedev, D. A.

    1996-05-01

    During the detonation synthesis, diamonds of ˜3 nm in size are produced from the excess carbon released in explosion. Coagulation occurs generally well below the melting temperature. Molecular dynamic simulations within the framework of simple Lennard-Jones model showed important features of interacting carbon clusters: 1) Coagulation is exothermic, and small clusters merge as liquid drops. Clusters larger than ˜3 nm unite keeping their shape, but surface atoms are in quasimolten state and can migrate between two grains. This "wetting" is rather slow. For small clusters there exist considerable temperature fluctuations due to interaction with the thermal bath. 2) Coagulation is accompanied by strong tensions. Both positive and negative pressure phases during the collision can reach ˜30 GPa. This can explain why the region of good diamond yield lies on P-T plane much higher than the graphite-diamond transition line.

  20. Nuclear deformation effects in the cluster radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Misicu, S. [Department of Theoretical Physics, NINPE-HH, Bucharest-Magurele (Romania); Protopopescu, D. [Frank Laboratory of Neutron Physics, JINR, Dubna (Russian Federation)

    1999-01-01

    We investigate the influence of the nuclear deformation on the decay rates of some cluster emission processes. The interaction between the daughter and the cluster is given by a double folding potential including quadrupole and hexadecapole deformed densities of both fragments. The nuclear part of the nucleus-nucleus interaction is density dependent and at small distances a repulsive core in the potential will occur. In the frame of the WKB-approximation the assault frequency of the cluster will depend on the geometric properties of the potential pocket whereas the penetrability will be sensitive to changes in the barrier location. The results obtained in this paper point out that various combinations of cluster and daughter deformations may account for the measured values of the decay rate. The decay rates are however more sensitive to the changes in the daughter deformation due to the large mass asymmetry of the process. (author) 10 refs, 6 figs, 1 tab

  1. Nuclear Deformation Effects in the Cluster Radioactivity

    Science.gov (United States)

    Misicu, Serban; Protopopescu, Dan

    1999-01-01

    We investigate the influence of the nuclear deformation on the decay rates of some cluster emission processes. The interaction between the daughter and the cluster is given by a double folding potential including quadrupole and hexadecupole deformed densities of both fragments. The nuclear part of the nucleus--nucleus interaction is density dependent and at small distances a repulsive core in the potential will occur. In the frame of the WKB-approximation the assault frequency of the cluster will depend on the geometric properties of the potential pocket whereas the penetrability will be sensitive to changes in the barrier location. The results obtained in this paper point out that various combinations of cluster and daughter deformations may account for the measured values of the decay rate. The decay rates are however more sensitive to the changes in the daughter deformation due to the large mass asymmetry of the process.

  2. Nuclear Deformation Effects in the Cluster Radioactivity

    CERN Document Server

    Misicu, S

    1998-01-01

    We investigate the influence of the nuclear deformation on the decay rates of some cluster emission processes. The interaction between the daughter and the cluster is given by a double folding potential including quadrupole and hexadecupole deformed densities of both fragments. The nuclear part of the nucleus-nucleus interaction is density dependent and at small distances a repulsive core in the potential will occur. In the frame of the WKB-approximation the assault frequency of the cluster will depend on the geometric properties of the potential pocket whereas the penetrability will be sensitive to changes in the barrier location. The results obtained in this paper point out that various combinations of cluster and daughter deformations may account for the measured values of the decay rate.

  3. Clustering of Galaxies in Brane World Models

    CERN Document Server

    Hameeda, Mir; Ali, Ahmed Farag

    2015-01-01

    In this paper, we analyze the clustering of galaxies using a modified Newtonian potential. This modification of the Newtonian potential occurs due to the existence of extra dimensions in brane world models. We will analyze a system of galaxies interacting with each other through this modified Newtonian potential. The partition function for this system of galaxies will be calculated, and this partition function will be used to calculate the free energy of this system of galaxies. The entropy and the chemical potential for this system will also be calculated. We will derive an explicit expression for the clustering parameter for this system. This parameter will determine the behavior of this system, and we will be able to express various thermodynamic quantities using this clustering parameter. Thus, we will be able to explicitly analyze the effect that modifying the Newtonian potential can have on the clustering of galaxies.

  4. Clustering of galaxies in brane world models

    Science.gov (United States)

    Hameeda, Mir; Faizal, Mir; Ali, Ahmed Farag

    2016-04-01

    In this paper, we analyze the clustering of galaxies using a modified Newtonian potential. This modification of the Newtonian potential occurs due to the existence of extra dimensions in brane world models. We will analyze a system of galaxies interacting with each other through this modified Newtonian potential. The partition function for this system of galaxies will be calculated, and this partition function will be used to calculate the free energy of this system of galaxies. The entropy and the chemical potential for this system will also be calculated. We will derive explicit expression for the clustering parameter for this system. This parameter will determine the behavior of this system, and we will be able to express various thermodynamic quantities using this clustering parameter. Thus, we will be able to explicitly analyze the effect that modifying the Newtonian potential can have on the clustering of galaxies. We also analyse the effect of extra dimensions on the two-point functions between galaxies.

  5. Electron spectra and structure of atomic and molecular clusters

    Energy Technology Data Exchange (ETDEWEB)

    Dehmer, Patricia M.

    1980-01-01

    Changes in electronic structure that occur during the stepwise transition from gas phase monomers to large clusters which resemble the condensed phase were studied. This basic information on weakly bound clusters is critical to the understanding of such phenomena as nucleation, aerosol formation, catalysis, and gas-to-particle conversion, yet there exist almost no experimental data on neutral particle energy levels or binding energies as a function of cluster size. (GHT)

  6. CSR in Industrial Clusters

    DEFF Research Database (Denmark)

    Lund-Thomsen, Peter; Pillay, Renginee G.

    2012-01-01

    Purpose – The paper seeks to review the literature on CSR in industrial clusters in developing countries, identifying the main strengths, weaknesses, and gaps in this literature, pointing to future research directions and policy implications in the area of CSR and industrial cluster development...... in this field and their comments incorporated in the final version submitted to Corporate Governance. Findings – The article traces the origins of the debate on industrial clusters and CSR in developing countries back to the early 1990s when clusters began to be seen as an important vehicle for local economic...... development in the South. At the turn of the millennium the industrial cluster debate expanded as clusters were perceived as a potential source of poverty reduction, while their role in promoting CSR among small and medium-sized enterprises began to take shape from 2006 onwards. At present, there is still...

  7. Cosmology with cluster surveys

    Indian Academy of Sciences (India)

    Subhabrata Majumdar

    2004-10-01

    Surveys of clusters of galaxies provide us with a powerful probe of the density and nature of the dark energy. The red-shift distribution of detected clusters is highly sensitive to the dark energy equation of state parameter . Upcoming Sunyaev–Zel'dovich (SZ) surveys would provide us large yields of clusters to very high red-shifts. Self-calibration of cluster scaling relations, possible for such a huge sample, would be able to constrain systematic biases on mass estimators. Combining cluster red-shift abundance with limited mass follow-up and cluster mass power spectrum can then give constraints on , as well as on 8 and to a few per cents.

  8. Melting of sodium clusters

    CERN Document Server

    Reyes-Nava, J A; Beltran, M R; Michaelian, K

    2002-01-01

    Thermal stability properties and the melting-like transition of Na_n, n=13-147, clusters are studied through microcanonical molecular dynamics simulations. The metallic bonding in the sodium clusters is mimicked by a many-body Gupta potential based on the second moment approximation of a tight-binding Hamiltonian. The characteristics of the solid-to-liquid transition in the sodium clusters are analyzed by calculating physical quantities like caloric curves, heat capacities, and root-mean-square bond length fluctuations using simulation times of several nanoseconds. Distinct melting mechanisms are obtained for the sodium clusters in the size range investigated. The calculated melting temperatures show an irregular variation with the cluster size, in qualitative agreement with recent experimental results. However, the calculated melting point for the Na_55 cluster is about 40 % lower than the experimental value.

  9. Online Correlation Clustering

    CERN Document Server

    Mathieu, Claire; Schudy, Warren

    2010-01-01

    We study the online clustering problem where data items arrive in an online fashion. The algorithm maintains a clustering of data items into similarity classes. Upon arrival of v, the relation between v and previously arrived items is revealed, so that for each u we are told whether v is similar to u. The algorithm can create a new cluster for v and merge existing clusters. When the objective is to minimize disagreements between the clustering and the input, we prove that a natural greedy algorithm is O(n)-competitive, and this is optimal. When the objective is to maximize agreements between the clustering and the input, we prove that the greedy algorithm is .5-competitive; that no online algorithm can be better than .834-competitive; we prove that it is possible to get better than 1/2, by exhibiting a randomized algorithm with competitive ratio .5+c for a small positive fixed constant c.

  10. Cluster Correspondence Analysis.

    Science.gov (United States)

    van de Velden, M; D'Enza, A Iodice; Palumbo, F

    2017-03-01

    A method is proposed that combines dimension reduction and cluster analysis for categorical data by simultaneously assigning individuals to clusters and optimal scaling values to categories in such a way that a single between variance maximization objective is achieved. In a unified framework, a brief review of alternative methods is provided and we show that the proposed method is equivalent to GROUPALS applied to categorical data. Performance of the methods is appraised by means of a simulation study. The results of the joint dimension reduction and clustering methods are compared with the so-called tandem approach, a sequential analysis of dimension reduction followed by cluster analysis. The tandem approach is conjectured to perform worse when variables are added that are unrelated to the cluster structure. Our simulation study confirms this conjecture. Moreover, the results of the simulation study indicate that the proposed method also consistently outperforms alternative joint dimension reduction and clustering methods.

  11. Clustering Categorical Data:A Cluster Ensemble Approach

    Institute of Scientific and Technical Information of China (English)

    He Zengyou(何增友); Xu Xiaofei; Deng Shengchun

    2003-01-01

    Clustering categorical data, an integral part of data mining,has attracted much attention recently. In this paper, the authors formally define the categorical data clustering problem as an optimization problem from the viewpoint of cluster ensemble, and apply cluster ensemble approach for clustering categorical data. Experimental results on real datasets show that better clustering accuracy can be obtained by comparing with existing categorical data clustering algorithms.

  12. Spatial Scan Statistic: Selecting clusters and generating elliptic clusters

    DEFF Research Database (Denmark)

    Christiansen, Lasse Engbo; Andersen, Jens Strodl

    2004-01-01

    The spatial scan statistic is widely used to search for clusters. This paper shows that the usually applied elimination of overlapping clusters to find secondary clusters is sensitive to smooth changes in the shape of the clusters. We present an algorithm for generation of set of confocal elliptic...... clusters. In addition, we propose a new way to present the information in a given set of clusters based on the significance of the clusters....

  13. Spatial suicide clusters in Australia between 2010 and 2012: a comparison of cluster and non-cluster among young people and adults.

    Science.gov (United States)

    Robinson, Jo; Too, Lay San; Pirkis, Jane; Spittal, Matthew J

    2016-11-22

    A suicide cluster has been defined as a group of suicides that occur closer together in time and space than would normally be expected. We aimed to examine the extent to which suicide clusters exist among young people and adults in Australia and to determine whether differences exist between cluster and non-cluster suicides. Suicide data were obtained from the National Coronial Information System for the period 2010 and 2012. Data on date of death, postcode, age at the time of death, sex, suicide method, ICD-10 code for cause of death, marital status, employment status, and aboriginality were retrieved. We examined the presence of spatial clusters separately for youth suicides and adult suicides using the Scan statistic. Pearson's chi-square was used to compare the characteristics of cluster suicides with non-cluster suicides. We identified 12 spatial clusters between 2010 and 2012. Five occurred among young people (n = 53, representing 5.6% [53/940] of youth suicides) and seven occurred among adults (n = 137, representing 2.3% [137/5939] of adult suicides). Clusters ranged in size from three to 21 for youth and from three to 31 for adults. When compared to adults, suicides by young people were significantly more likely to occur as part of a cluster (difference = 3.3%, 95% confidence interval [CI] = 1.8 to 4.8, p Suicides by people with an Indigenous background were also significantly more likely to occur in a cluster than suicide by non-Indigenous people and this was the case among both young people and adults. Suicide clusters have a significant negative impact on the communities in which they occur. As a result it is important to find effective ways of managing and containing suicide clusters. To date there is limited evidence for the effectiveness of those strategies typically employed, in particular in Indigenous settings, and developing this evidence base needs to be a future priority. Future research that examines in more depth the socio

  14. Clustering of Absorbers

    CERN Document Server

    Cristiani, S; D'Odorico, V; Fontana, A; Giallongo, E; Moscardini, L; Savaglio, S

    1997-01-01

    The observed clustering of Lyman-$\\alpha$ lines is reviewed and compared with the clustering of CIV systems. We argue that a continuity of properties exists between Lyman-$\\alpha$ and metal systems and show that the small-scale clustering of the absorbers is consistent with a scenario of gravitationally induced correlations. At large scales statistically significant over and under-densities (including voids) are found on scales of tens of Mpc.

  15. Clustering Techniques in Bioinformatics

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Masood

    2015-01-01

    Full Text Available Dealing with data means to group information into a set of categories either in order to learn new artifacts or understand new domains. For this purpose researchers have always looked for the hidden patterns in data that can be defined and compared with other known notions based on the similarity or dissimilarity of their attributes according to well-defined rules. Data mining, having the tools of data classification and data clustering, is one of the most powerful techniques to deal with data in such a manner that it can help researchers identify the required information. As a step forward to address this challenge, experts have utilized clustering techniques as a mean of exploring hidden structure and patterns in underlying data. Improved stability, robustness and accuracy of unsupervised data classification in many fields including pattern recognition, machine learning, information retrieval, image analysis and bioinformatics, clustering has proven itself as a reliable tool. To identify the clusters in datasets algorithm are utilized to partition data set into several groups based on the similarity within a group. There is no specific clustering algorithm, but various algorithms are utilized based on domain of data that constitutes a cluster and the level of efficiency required. Clustering techniques are categorized based upon different approaches. This paper is a survey of few clustering techniques out of many in data mining. For the purpose five of the most common clustering techniques out of many have been discussed. The clustering techniques which have been surveyed are: K-medoids, K-means, Fuzzy C-means, Density-Based Spatial Clustering of Applications with Noise (DBSCAN and Self-Organizing Map (SOM clustering.

  16. Structures in Galaxy Clusters

    CERN Document Server

    Escalera, E; Girardi, M; Giuricin, G; Mardirossian, F; Mazure, A; Mezzetti, M

    1993-01-01

    The analysis of the presence of substructures in 16 well-sampled clusters of galaxies suggests a stimulating hypothesis: Clusters could be classified as unimodal or bimodal, on the basis of to the sub-clump distribution in the {\\em 3-D} space of positions and velocities. The dynamic study of these clusters shows that their fundamental characteristics, in particular the virial masses, are not severely biased by the presence of subclustering if the system considered is bound.

  17. Tangling clustering instability for small particles in temperature stratified turbulence

    CERN Document Server

    Elperin, Tov; Liberman, Michael; Rogachevskii, Igor

    2013-01-01

    We study particle clustering in a temperature stratified turbulence with small finite correlation time. It is shown that the temperature stratified turbulence strongly increases the degree of compressibility of particle velocity field. This results in the strong decrease of the threshold for the excitation of the tangling clustering instability even for small particles. The tangling clustering instability in the temperature stratified turbulence is essentially different from the inertial clustering instability that occurs in non-stratified isotropic and homogeneous turbulence. While the inertial clustering instability is caused by the centrifugal effect of the turbulent eddies, the mechanism of the tangling clustering instability is related to the temperature fluctuations generated by the tangling of the mean temperature gradient by the velocity fluctuations. Temperature fluctuations produce pressure fluctuations and cause particle clustering in regions with increased pressure fluctuations. It is shown that t...

  18. The Youngest Globular Clusters

    CERN Document Server

    Beck, Sara

    2014-01-01

    It is likely that all stars are born in clusters, but most clusters are not bound and disperse. None of the many protoclusters in our Galaxy are likely to develop into long-lived bound clusters. The Super Star Clusters (SSCs) seen in starburst galaxies are more massive and compact and have better chances of survival. The birth and early development of SSCs takes place deep in molecular clouds, and during this crucial stage the embedded clusters are invisible to optical or UV observations but are studied via the radio-infared supernebulae (RISN) they excite. We review observations of embedded clusters and identify RISN within 10 Mpc whose exciting clusters have a million solar masses or more in volumes of a few cubic parsecs and which are likely to not only survive as bound clusters, but to evolve into objects as massive and compact as Galactic globulars. These clusters are distinguished by very high star formation efficiency eta, at least a factor of 10 higher than the few percent seen in the Galaxy, probably...

  19. Star Clusters within FIRE

    Science.gov (United States)

    Perez, Adrianna; Moreno, Jorge; Naiman, Jill; Ramirez-Ruiz, Enrico; Hopkins, Philip F.

    2017-01-01

    In this work, we analyze the environments surrounding star clusters of simulated merging galaxies. Our framework employs Feedback In Realistic Environments (FIRE) model (Hopkins et al., 2014). The FIRE project is a high resolution cosmological simulation that resolves star forming regions and incorporates stellar feedback in a physically realistic way. The project focuses on analyzing the properties of the star clusters formed in merging galaxies. The locations of these star clusters are identified with astrodendro.py, a publicly available dendrogram algorithm. Once star cluster properties are extracted, they will be used to create a sub-grid (smaller than the resolution scale of FIRE) of gas confinement in these clusters. Then, we can examine how the star clusters interact with these available gas reservoirs (either by accreting this mass or blowing it out via feedback), which will determine many properties of the cluster (star formation history, compact object accretion, etc). These simulations will further our understanding of star formation within stellar clusters during galaxy evolution. In the future, we aim to enhance sub-grid prescriptions for feedback specific to processes within star clusters; such as, interaction with stellar winds and gas accretion onto black holes and neutron stars.

  20. Galaxy Clusters with Chandra

    CERN Document Server

    Forman, W; Markevitch, M L; Vikhlinin, A A; Churazov, E

    2002-01-01

    We discuss Chandra results related to 1) cluster mergers and cold fronts and 2) interactions between relativistic plasma and hot cluster atmospheres. We describe the properties of cold fronts using NGC1404 in the Fornax cluster and A3667 as examples. We discuss multiple surface brightness discontinuities in the cooling flow cluster ZW3146. We review the supersonic merger underway in CL0657. Finally, we summarize the interaction between plasma bubbles produced by AGN and hot gas using M87 and NGC507 as examples.

  1. 15th Cluster workshop

    CERN Document Server

    Laakso, Harri; Escoubet, C. Philippe; The Cluster Active Archive : Studying the Earth’s Space Plasma Environment

    2010-01-01

    Since the year 2000 the ESA Cluster mission has been investigating the small-scale structures and processes of the Earth's plasma environment, such as those involved in the interaction between the solar wind and the magnetospheric plasma, in global magnetotail dynamics, in cross-tail currents, and in the formation and dynamics of the neutral line and of plasmoids. This book contains presentations made at the 15th Cluster workshop held in March 2008. It also presents several articles about the Cluster Active Archive and its datasets, a few overview papers on the Cluster mission, and articles reporting on scientific findings on the solar wind, the magnetosheath, the magnetopause and the magnetotail.

  2. Inbreeding and purging at the genomic Level: the Chillingham cattle reveal extensive, non-random SNP heterozygosity.

    Science.gov (United States)

    Williams, J L; Hall, S J G; Del Corvo, M; Ballingall, K T; Colli, L; Ajmone Marsan, P; Biscarini, F

    2016-02-01

    Local breeds of livestock are of conservation significance as components of global biodiversity and as reservoirs of genetic variation relevant to the future sustainability of agriculture. One such rare historic breed, the Chillingham cattle of northern England, has a 350-year history of isolation and inbreeding yet shows no diminution of viability or fertility. The Chillingham cattle have not been subjected to selective breeding. It has been suggested previously that the herd has minimal genetic variation. In this study, high-density SNP genotyping with the 777K SNP chip showed that 9.1% of loci on the chip are polymorphic in the herd, compared with 62-90% seen in commercial cattle breeds. Instead of being homogeneously distributed along the genome, these loci are clustered at specific chromosomal locations. A high proportion of the Chillingham individuals examined were heterozygous at many of these polymorphic loci, suggesting that some loci are under balancing selection. Some of these frequently heterozygous loci have been implicated as sites of recessive lethal mutations in cattle. Linkage disequilibrium equal or close to 100% was found to span up to 1350 kb, and LD was above r(2) = 0.25 up to more than 5000 kb. This strong LD is consistent with the lack of polymorphic loci in the herd. The heterozygous regions in the Chillingham cattle may be the locations of genes relevant to fitness or survival, which may help elucidate the biology of local adaptation in traditional breeds and facilitate selection for such traits in commercial cattle.

  3. On the use of robust estimators for standard errors in the presence of clustering when clustering membership is misspecified.

    Science.gov (United States)

    Desai, Manisha; Bryson, Susan W; Robinson, Thomas

    2013-03-01

    This paper examines the implications of using robust estimators (REs) of standard errors in the presence of clustering when cluster membership is unclear as may commonly occur in clustered randomized trials. For example, in such trials, cluster membership may not be recorded for one or more treatment arms and/or cluster membership may be dynamic. When clusters are well defined, REs have properties that are robust to misspecification of the correlation structure. To examine whether results were sensitive to assumptions about the clustering membership, we conducted simulation studies for a two-arm clinical trial, where the number of clusters, the intracluster correlation (ICC), and the sample size varied. REs of standard errors that incorrectly assumed clustering of data that were truly independent yielded type I error rates of up to 40%. Partial and complete misspecifications of membership (where some and no knowledge of true membership were incorporated into assumptions) for data generated from a large number of clusters (50) with a moderate ICC (0.20) yielded type I error rates that ranged from 7.2% to 9.1% and 10.5% to 45.6%, respectively; incorrectly assuming independence gave a type I error rate of 10.5%. REs of standard errors can be useful when the ICC and knowledge of cluster membership are high. When the ICC is weak, a number of factors must be considered. Our findings suggest guidelines for making sensible analytic choices in the presence of clustering.

  4. Statistical properties of convex clustering

    OpenAIRE

    Tan, Kean Ming; Witten, Daniela

    2015-01-01

    In this manuscript, we study the statistical properties of convex clustering. We establish that convex clustering is closely related to single linkage hierarchical clustering and $k$-means clustering. In addition, we derive the range of the tuning parameter for convex clustering that yields a non-trivial solution. We also provide an unbiased estimator of the degrees of freedom, and provide a finite sample bound for the prediction error for convex clustering. We compare convex clustering to so...

  5. Document Clustering Based on Semi-Supervised Term Clustering

    Directory of Open Access Journals (Sweden)

    Hamid Mahmoodi

    2012-05-01

    Full Text Available The study is conducted to propose a multi-step feature (term selection process and in semi-supervised fashion, provide initial centers for term clusters. Then utilize the fuzzy c-means (FCM clustering algorithm for clustering terms. Finally assign each of documents to closest associated term clusters. While most text clustering algorithms directly use documents for clustering, we propose to first group the terms using FCM algorithm and then cluster documents based on terms clusters. We evaluate effectiveness of our technique on several standard text collections and compare our results with the some classical text clustering algorithms.

  6. Space and time clustering of mortality in rural South Africa (Agincourt HDSS, 1992–2007

    Directory of Open Access Journals (Sweden)

    Benn Sartorius

    2010-08-01

    Full Text Available Background: Detailed information regarding the spatial and/or spatial–temporal distribution of mortality is required for the efficient implementation and targeting of public health interventions. Objectives: Identify high risk clusters of mortality within the Agincourt subdistrict for targeting of public health interventions, and highlight areas for further research. Design: Mortality data were extracted from the Agincourt health and socio-demographic surveillance system (HDSS for the period 1992–2007. Mortality rates by age group and time were calculated assuming a Poisson distribution and using precise person-time contribution estimates. A spatial scan statistic (Kulldorff was used to test for clusters of age group specific all-cause and cause-specific mortality both in space and time. Results: Many statistically significant clusters of higher all-cause and cause-specific mortality were identified both in space and time. Specific areas were consistently identified as high risk areas; namely, the east/south- east and upper east central regions. This corresponds to areas with higher mortality due to communicable causes (especially HIV/TB and diarrheal disease and indicates a non-random element to the distribution of potential underlying causative factors e.g. settlements comprising former Mozambican refugees in east/south-east of the site, corresponding higher poverty areas, South African villages with higher HIV prevalence, etc. Clusters of older adult mortality were also observed indicating potential non-random distribution of non-communicable disease mortality. Conclusion: This study has highlighted distinct clusters of all-cause and cause-specific mortality within the Agincourt subdistrict. It is a first step in prioritizing areas for further, more detailed research as well as for future public health follow-on efforts such as targeting of vertical prevention of HIV/TB and antiretroviral rollout in significant child and adult mortality

  7. Non-random escape pathways from a broadly neutralizing human monoclonal antibody map to a highly conserved region on the hepatitis C virus E2 glycoprotein encompassing amino acids 412-423.

    Directory of Open Access Journals (Sweden)

    Zhen-yong Keck

    2014-08-01

    Full Text Available A challenge for hepatitis C virus (HCV vaccine development is to define epitopes that are able to elicit protective antibodies against this highly diverse virus. The E2 glycoprotein region located at residues 412-423 is conserved and antibodies to 412-423 have broadly neutralizing activities. However, an adaptive mutation, N417S, is associated with a glycan shift in a variant that cannot be neutralized by a murine but by human monoclonal antibodies (HMAbs against 412-423. To determine whether HCV escapes from these antibodies, we analyzed variants that emerged when cell culture infectious HCV virions (HCVcc were passaged under increasing concentrations of a specific HMAb, HC33.1. Multiple nonrandom escape pathways were identified. Two pathways occurred in the context of an N-glycan shift mutation at N417T. At low antibody concentrations, substitutions of two residues outside of the epitope, N434D and K610R, led to variants having improved in vitro viral fitness and reduced sensitivity to HC33.1 binding and neutralization. At moderate concentrations, a S419N mutation occurred within 412-423 in escape variants that have greatly reduced sensitivity to HC33.1 but compromised viral fitness. Importantly, the variants generated from these pathways differed in their stability. N434D and K610R-associated variants were stable and became dominant as the virions were passaged. The S419N mutation reverted back to N419S when immune pressure was reduced by removing HC33.1. At high antibody concentrations, a mutation at L413I was observed in variants that were resistant to HC33.1 neutralization. Collectively, the combination of multiple escape pathways enabled the virus to persist under a wide range of antibody concentrations. Moreover, these findings pose a different challenge to vaccine development beyond the identification of highly conserved epitopes. It will be necessary for a vaccine to induce high potency antibodies that prevent the formation of escape

  8. Cost-Effective Clustering

    CERN Document Server

    Gottlieb, S

    2001-01-01

    Small Beowulf clusters can effectively serve as personal or group supercomputers. In such an environment, a cluster can be optimally designed for a specific problem (or a small set of codes). We discuss how theoretical analysis of the code and benchmarking on similar hardware lead to optimal systems.

  9. [Cluster headache differential diagnosis].

    Science.gov (United States)

    Guégan-Massardier, Evelyne; Laubier, Cécile

    2015-11-01

    Cluster headache is characterized by disabling stereotyped headache. Early diagnosis allows appropriate treatment, unfortunately diagnostic errors are frequent. The main differential diagnoses are other primary or essential headaches. Migraine, more frequent and whose diagnosis is carried by excess, trigeminal neuralgia or other trigemino-autonomic cephalgia. Vascular or tumoral underlying condition can mimic cluster headache, neck and brain imaging is recommended, ideally MRI.

  10. Coma cluster of galaxies

    Science.gov (United States)

    1999-01-01

    Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

  11. Mixed-Initiative Clustering

    Science.gov (United States)

    Huang, Yifen

    2010-01-01

    Mixed-initiative clustering is a task where a user and a machine work collaboratively to analyze a large set of documents. We hypothesize that a user and a machine can both learn better clustering models through enriched communication and interactive learning from each other. The first contribution or this thesis is providing a framework of…

  12. Cluster Synchronization Algorithms

    NARCIS (Netherlands)

    Xia, Weiguo; Cao, Ming

    2010-01-01

    This paper presents two approaches to achieving cluster synchronization in dynamical multi-agent systems. In contrast to the widely studied synchronization behavior, where all the coupled agents converge to the same value asymptotically, in the cluster synchronization problem studied in this paper,

  13. Neurostimulation in cluster headache

    DEFF Research Database (Denmark)

    Pedersen, Jeppe L; Barloese, Mads; Jensen, Rigmor H

    2013-01-01

    PURPOSE OF REVIEW: Neurostimulation has emerged as a viable treatment for intractable chronic cluster headache. Several therapeutic strategies are being investigated including stimulation of the hypothalamus, occipital nerves and sphenopalatine ganglion. The aim of this review is to provide...... effective strategy must be preferred as first-line therapy for intractable chronic cluster headache....

  14. Securing personal network clusters

    NARCIS (Netherlands)

    Jehangir, Assed; Heemstra de Groot, Sonia M.

    2007-01-01

    A Personal Network is a self-organizing, secure and private network of a user’s devices notwithstanding their geographic location. It aims to utilize pervasive computing to provide users with new and improved services. In this paper we propose a model for securing Personal Network clusters. Clusters

  15. Clustering Text Data Streams

    Institute of Scientific and Technical Information of China (English)

    Yu-Bao Liu; Jia-Rong Cai; Jian Yin; Ada Wai-Chee Fu

    2008-01-01

    Clustering text data streams is an important issue in data mining community and has a number of applications such as news group filtering, text crawling, document organization and topic detection and tracing etc. However, most methods are similarity-based approaches and only use the TF*IDF scheme to represent the semantics of text data and often lead to poor clustering quality. Recently, researchers argue that semantic smoothing model is more efficient than the existing TF.IDF scheme for improving text clustering quality. However, the existing semantic smoothing model is not suitable for dynamic text data context. In this paper, we extend the semantic smoothing model into text data streams context firstly. Based on the extended model, we then present two online clustering algorithms OCTS and OCTSM for the clustering of massive text data streams. In both algorithms, we also present a new cluster statistics structure named cluster profile which can capture the semantics of text data streams dynamically and at the same time speed up the clustering process. Some efficient implementations for our algorithms are also given. Finally, we present a series of experimental results illustrating the effectiveness of our technique.

  16. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan;

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace c...

  17. Structural transitions in clusters

    Science.gov (United States)

    Ghazali, A.; Lévy, J.-C. S.

    1997-02-01

    Monatomic clusters are studied by Monte Carlo relaxation using generalized Lennard-Jones potentials. A transition from an icosahedral symmetry to a crystalline symmetry with stacking faults is always observed. Bcc-based soft atom clusters are found to have a lower energy than the corresponding hcp and fcc ones below the melting point.

  18. Cluster Ions and Atmospheric Processes

    Science.gov (United States)

    D'Auria, R.; Turco, R. P.

    We investigate the properties and possible roles of naturally occurring ions under at- mospheric conditions. Among other things, the formation of stable charged molecular clusters represents the initial stages of aerosol nucleation [e.g., Keesee and Castle- man, 1982], while the conversion of vapor to aggregates is the first step in certain atmospheric phase transitions [e.g. Hamill and Turco, 2000]. We analyze the stability and size distributions of common ionic clusters by solving the differential equations describing their growth and loss. The necessary reaction rate coefficients are deter- mined using kinetic and thermodynamic data. The latter are derived from direct labo- ratory measurements of equilibrium constants, from the classical charged liquid drop model applied to large aggregates (i.e., the Thomson model [Thomson, 1906]), and from quantum mechanical calculations of the thermodynamic potentials associated with the cluster structures. This approach allows us to characterize molecular clusters across the entire size range from true molecular species to larger aggregates exhibiting macroscopic behavior [D'Auria, 2001]. Cluster systems discussed in this talk include the proton hydrates (PHs) and nitrate-water and nitrate-nitric acid series [D'Auria and Turco, 2001]. These ions have frequently been detected in the stratosphere and tropo- sphere [e.g., Arnold et al., 1977; Viggiano and Arnold, 1981]. We show how the pro- posed hybrid cluster model can be extended to a wide range of ion systems, including non-proton hydrates (NPHs), mixed-ligand clusters such as nitrate-water-nitric acid and sulfate-sulfuric acid-water, as well as more exotic species containing ammonia, pyridine and other organic compounds found on ions [e.g., Eisele, 1988; Tanner and Eisele, 1991]. References: Arnold, F., D. Krankowsky and K. H. Marien, First mass spectrometric measurements of posi- tive ions in the stratosphere, Nature, 267, 30-32, 1977. D'Auria, R., A study of ionic

  19. Mathematical classification and clustering

    CERN Document Server

    Mirkin, Boris

    1996-01-01

    I am very happy to have this opportunity to present the work of Boris Mirkin, a distinguished Russian scholar in the areas of data analysis and decision making methodologies. The monograph is devoted entirely to clustering, a discipline dispersed through many theoretical and application areas, from mathematical statistics and combina­ torial optimization to biology, sociology and organizational structures. It compiles an immense amount of research done to date, including many original Russian de­ velopments never presented to the international community before (for instance, cluster-by-cluster versions of the K-Means method in Chapter 4 or uniform par­ titioning in Chapter 5). The author's approach, approximation clustering, allows him both to systematize a great part of the discipline and to develop many in­ novative methods in the framework of optimization problems. The optimization methods considered are proved to be meaningful in the contexts of data analysis and clustering. The material presented in ...

  20. Neutrosophic Hierarchical Clustering Algoritms

    Directory of Open Access Journals (Sweden)

    Rıdvan Şahin

    2014-03-01

    Full Text Available Interval neutrosophic set (INS is a generalization of interval valued intuitionistic fuzzy set (IVIFS, whose the membership and non-membership values of elements consist of fuzzy range, while single valued neutrosophic set (SVNS is regarded as extension of intuitionistic fuzzy set (IFS. In this paper, we extend the hierarchical clustering techniques proposed for IFSs and IVIFSs to SVNSs and INSs respectively. Based on the traditional hierarchical clustering procedure, the single valued neutrosophic aggregation operator, and the basic distance measures between SVNSs, we define a single valued neutrosophic hierarchical clustering algorithm for clustering SVNSs. Then we extend the algorithm to classify an interval neutrosophic data. Finally, we present some numerical examples in order to show the effectiveness and availability of the developed clustering algorithms.

  1. Cool Cluster Correctly Correlated

    Energy Technology Data Exchange (ETDEWEB)

    Varganov, Sergey Aleksandrovich [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Atomic clusters are unique objects, which occupy an intermediate position between atoms and condensed matter systems. For a long time it was thought that physical and chemical properties of atomic dusters monotonically change with increasing size of the cluster from a single atom to a condensed matter system. However, recently it has become clear that many properties of atomic clusters can change drastically with the size of the clusters. Because physical and chemical properties of clusters can be adjusted simply by changing the cluster's size, different applications of atomic clusters were proposed. One example is the catalytic activity of clusters of specific sizes in different chemical reactions. Another example is a potential application of atomic clusters in microelectronics, where their band gaps can be adjusted by simply changing cluster sizes. In recent years significant advances in experimental techniques allow one to synthesize and study atomic clusters of specified sizes. However, the interpretation of the results is often difficult. The theoretical methods are frequently used to help in interpretation of complex experimental data. Most of the theoretical approaches have been based on empirical or semiempirical methods. These methods allow one to study large and small dusters using the same approximations. However, since empirical and semiempirical methods rely on simple models with many parameters, it is often difficult to estimate the quantitative and even qualitative accuracy of the results. On the other hand, because of significant advances in quantum chemical methods and computer capabilities, it is now possible to do high quality ab-initio calculations not only on systems of few atoms but on clusters of practical interest as well. In addition to accurate results for specific clusters, such methods can be used for benchmarking of different empirical and semiempirical approaches. The atomic clusters studied in this work contain from a few atoms

  2. Job Oriented Monitoring Clusters

    Directory of Open Access Journals (Sweden)

    Vijayalaxmi Cigala,

    2011-03-01

    Full Text Available There has been a lot of development in the field of clusters and grids. Recently, the use of clusters has been on rise in every possible field. This paper proposes a system that monitors jobs onlarge computational clusters. Monitoring jobs is essential to understand how jobs are being executed. This helps us in understanding the complete life cycle of the jobs being executed on large clusters. Also, this paper describes how the information obtained by monitoring the jobs would help in increasing the overall throughput of clusters. Heuristics help in efficient job distribution among the computational nodes, thereby accomplishing fair job distribution policy. The proposed system would be capable of loadbalancing among the computational nodes, detecting failures, taking corrective actions after failure detection, job monitoring, system resource monitoring, etc.

  3. On TPC cluster reconstruction

    CERN Document Server

    Dydak, F; Nefedov, Y; Wotschack, J; Zhemchugov, A

    2004-01-01

    For a bias-free momentum measurement of TPC tracks, the correct determination of cluster positions is mandatory. We argue in particular that (i) the reconstruction of the entire longitudinal signal shape in view of longitudinal diffusion, electronic pulse shaping, and track inclination is important both for the polar angle reconstruction and for optimum r phi resolution; and that (ii) self-crosstalk of pad signals calls for special measures for the reconstruction of the z coordinate. The problem of 'shadow clusters' is resolved. Algorithms are presented for accepting clusters as 'good' clusters, and for the reconstruction of the r phi and z cluster coordinates, including provisions for 'bad' pads and pads next to sector boundaries, respectively.

  4. A Commodity Computing Cluster

    Science.gov (United States)

    Teuben, P. J.; Wolfire, M. G.; Pound, M. W.; Mundy, L. G.

    We have assembled a cluster of Intel-Pentium based PCs running Linux to compute a large set of Photodissociation Region (PDR) and Dust Continuum models. For various reasons the cluster is heterogeneous, currently ranging from a single Pentium-II 333 MHz to dual Pentium-III 450 MHz CPU machines. Although this will be sufficient for our ``embarrassingly parallelizable problem'' it may present some challenges for as yet unplanned future use. In addition the cluster was used to construct a MIRIAD benchmark, and compared to equivalent Ultra-Sparc based workstations. Currently the cluster consists of 8 machines, 14 CPUs, 50GB of disk-space, and a total peak speed of 5.83 GHz, or about 1.5 Gflops. The total cost of this cluster has been about $12,000, including all cabling, networking equipment, rack, and a CD-R backup system. The URL for this project is http://dustem.astro.umd.edu.

  5. A comparison of substorms occurring during magnetic storms with those occurring during quiet times

    Science.gov (United States)

    McPherron, R. L.; Hsu, T.-S.

    2002-09-01

    It has been suggested that there may be a fundamental difference between substorms that occur during magnetic storms and those that occur at other times. [1996] presented evidence that there is no obvious change in lobe field in "quiet time" substorms but that "storm time" substorms exhibit the classic pattern of storage and release of lobe field energy. This result led them to speculate that the former are caused by current sheet disruption, while the latter are caused by reconnection of lobe flux. In this paper we examine their hypothesis with a much larger data set using definitions of the two types of substorms similar to theirs, as well as additional more restrictive definitions of these classes of events. Our results show that the only differences between the various classes are the absolute value of the lobe field and the size of the changes. When the data are normalized to unit field amplitude, we find that the percent change during storm time and non-storm time substorms is nearly the same. The above conclusions are demonstrated with superposed epoch analysis of lobe field (Bt and Bz) for four classes of substorms: active times (Dst -25 nT), and quiet time substorms (no evidence of storm in Dst). Epoch zero for the analysis was taken as the main substorm onset (Pi2 onset closest to sharp break in AL index). Our results suggest that there is no qualitative distinction between the various classes of substorms, and so they are all likely to be caused by the same mechanism.

  6. Patterns of white matter damage are non-random and associated with cognitive function in secondary progressive multiple sclerosis.

    Science.gov (United States)

    Meijer, K A; Cercignani, M; Muhlert, N; Sethi, V; Chard, D; Geurts, J J G; Ciccarelli, O

    2016-01-01

    matter tracts belonging to the same cluster, and thus with similar characteristics, tend to follow similar trends during neurodegeneration. Furthermore, these underlying FA patterns might help to explain cognitive dysfunction in SPMS.

  7. Opportunities for targeting the fatigue-anorexia-cachexia symptom cluster.

    Science.gov (United States)

    Alesi, Erin R; del Fabbro, Egidio

    2014-01-01

    Cancer patients experience multiple symptoms throughout their illness trajectory. Symptoms consistently occurring together, known as symptom clusters, share common pathophysiologic mechanisms. Understanding and targeting such symptom clusters may allow for more effective and efficient use of treatments for a variety of symptoms. Fatigue-anorexia-cachexia is one of the most prevalent symptom clusters and significantly impairs quality of life. In this review, we explore the fatigue-anorexia-cachexia symptom cluster and focus on current and emerging therapies with an emphasis on pharmacologic management.

  8. Solvation and chemical reaction of sodium in water clusters

    Science.gov (United States)

    Bobbert, C.; Schulz, C. P.

    Nam(H2O)n Clusters ( n = 1...200, m = 1...50) are formed in a recently build pick-up arrangement. Preformed water clusters traverse a sodium oven, where sodium atoms are picked up. At low sodium vapour pressure ( 1×10-3 mbar) the water cluster pick up more than 50 Na atoms and reaction products Na(NaOH)n ( n = 2, 4...50) dominate the mass spectra. The even number of NaOH units in the products indicate that also in a finite cluster the reaction occurs in pairs as in the macroscopic reaction.

  9. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-05-01

    Full Text Available The distribution of ionic species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia are also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4x(HSO4x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4(H2SO4x]clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (> m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by

  10. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-08-01

    Full Text Available The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4 x(HSO4 x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4 (H2SO4 x] clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition

  11. Document clustering methods, document cluster label disambiguation methods, document clustering apparatuses, and articles of manufacture

    Science.gov (United States)

    Sanfilippo, Antonio [Richland, WA; Calapristi, Augustin J [West Richland, WA; Crow, Vernon L [Richland, WA; Hetzler, Elizabeth G [Kennewick, WA; Turner, Alan E [Kennewick, WA

    2009-12-22

    Document clustering methods, document cluster label disambiguation methods, document clustering apparatuses, and articles of manufacture are described. In one aspect, a document clustering method includes providing a document set comprising a plurality of documents, providing a cluster comprising a subset of the documents of the document set, using a plurality of terms of the documents, providing a cluster label indicative of subject matter content of the documents of the cluster, wherein the cluster label comprises a plurality of word senses, and selecting one of the word senses of the cluster label.

  12. Software-Defined Cluster

    Institute of Scientific and Technical Information of China (English)

    聂华; 杨晓君; 刘淘英

    2015-01-01

    The cluster architecture has played an important role in high-end computing for the past 20 years. With the advent of Internet services, big data, and cloud computing, traditional clusters face three challenges: 1) providing flexible system balance among computing, memory, and I/O capabilities;2) reducing resource pooling overheads;and 3) addressing low performance-power efficiency. This position paper proposes a software-defined cluster (SDC) architecture to deal with these challenges. The SDC architecture inherits two features of traditional cluster: its architecture is multicomputer and it has loosely-coupled interconnect. SDC provides two new mechanisms: global I/O space (GIO) and hardware-supported native access (HNA) to remote devices. Application software can define a virtual cluster best suited to its needs from resources pools provided by a physical cluster, and traditional cluster ecosystems need no modification. We also discuss a prototype design and implementation of a 32-processor cloud server utilizing the SDC architecture.

  13. Cluster knockout reactions

    Indian Academy of Sciences (India)

    Arun K Jain; B N Joshi

    2014-04-01

    Cluster knockout reactions are expected to reveal the amount of clustering (such as that of , d and even of heavier clusters such as 12C, 16O etc.) in the target nucleus. In simple terms, incident medium high-energy nuclear projectile interacts strongly with the cluster (present in the target nucleus) as if it were existing as a free entity. Theoretically, the relatively softer interactions of the two outgoing particles with the residual nucleus lead to optical distortions and are treated in terms of distorted wave (DW) formalism. The long-range projectile–cluster interaction is accounted for, in terms of the finite range (FR) direct reaction formalism, as against the more commonly adopted zero-range (ZR) distorted wave impulse approximation (DWIA) formalism. Comparison of the DWIA calculations with the observed data provide information about the momentum distribution and the clustering spectroscopic factor of the target nucleus. Interesting results and some recent advancements in the area of (, 2) reactions and heavy cluster knockout reactions are discussed. Importance of the finite-range vertex and the final-state interactions are brought out.

  14. Packing Transitions in Nanosized Li Clusters

    CERN Document Server

    Sung, M W; Weare, J H; Sung, Ming Wen; Kawai, Ryoichi; Weare, John H.

    1994-01-01

    Packing transitions in the lowest energy structures of Li clusters as a function of size have been identified via simulated annealing. For N>21, the large $p$ character of Li leads to unexpected ionic structures. At N~25, a packing pattern based on interpenetrating 13-atom icosahedra and similar to that of Na and K appears. This pattern persists until at N=55, where another transition to a structure based on a Mackay icosahedron occurs. For clusters of size 55 and 147, the optimized FCC structure representative of the bulk is still slightly higher in energy than the optimal MIC. (RK-94-03)

  15. Textile Industrial Clusters in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    "National Textile Industry Cluster Development Seminar" convened, held by China National Textile and Apparel Council, 23 cities and towns were awarded as China’s Textile Industry Cluster Pilot District. By far, China’s textile industrial clusters have grown

  16. Spanning Tree Based Attribute Clustering

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Jorge, Cordero Hernandez

    2009-01-01

    inconsistent edges from a maximum spanning tree by starting appropriate initial modes, therefore generating stable clusters. It discovers sound clusters through simple graph operations and achieves significant computational savings. We compare the Star Discovery algorithm against earlier attribute clustering...

  17. An intervention to reduce HIV risk behavior of substance-using men who have sex with men: a two-group randomized trial with a nonrandomized third group.

    Directory of Open Access Journals (Sweden)

    Gordon Mansergh

    Full Text Available BACKGROUND: Substance use during sex is associated with sexual risk behavior among men who have sex with men (MSM, and MSM continue to be the group at highest risk for incident HIV in the United States. The objective of this study is to test the efficacy of a group-based, cognitive-behavioral intervention to reduce risk behavior of substance-using MSM, compared to a randomized attention-control group and a nonrandomized standard HIV-testing group. METHODS AND FINDINGS: Participants (n = 1,686 were enrolled in Chicago, Los Angeles, New York City, and San Francisco and randomized to a cognitive-behavioral intervention or attention-control comparison. The nonrandomized group received standard HIV counseling and testing. Intervention group participants received six 2-h group sessions focused on reducing substance use and sexual risk behavior. Attention-control group participants received six 2-h group sessions of videos and discussion of MSM community issues unrelated to substance use, sexual risk, and HIV/AIDS. All three groups received HIV counseling and testing at baseline. The sample reported high-risk behavior during the past 3 mo prior to their baseline visit: 67% reported unprotected anal sex, and 77% reported substance use during their most recent anal sex encounter with a nonprimary partner. The three groups significantly (p0.05 from each other at 3-, 6-, and 12-mo follow-up. Outcomes for the 2-arm comparisons were not significantly different at 12-mo follow-up (e.g., unprotected anal sex, odds ratio = 1.14, confidence interval = 0.86-1.51, nor at earlier time points. Similar results were found for each outcome variable in both 2- and 3-arm comparisons. CONCLUSIONS: These results for reducing sexual risk behavior of substance-using MSM are consistent with results of intervention trials for other populations, which collectively suggest critical challenges for the field of HIV behavioral interventions. Several mechanisms may contribute to

  18. COOL CORE CLUSTERS FROM COSMOLOGICAL SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Rasia, E.; Borgani, S.; Murante, G.; Planelles, S.; Biffi, V.; Granato, G. L. [INAF, Osservatorio Astronomico di Trieste, via Tiepolo 11, I-34131, Trieste (Italy); Beck, A. M.; Steinborn, L. K.; Dolag, K. [Universitäts-Sternwarte München, Scheinerstr.1, D-81679 München (Germany); Ragone-Figueroa, C., E-mail: rasia@oats.inaf.it [Instituto de Astronomá Teórica y Experimental (IATE), Consejo Nacional de Investigaciones Cientiíficas y Técnicas de la República Argentina (CONICET), Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, X5000BGR, Córdoba (Argentina)

    2015-11-01

    We present results obtained from a set of cosmological hydrodynamic simulations of galaxy clusters, aimed at comparing predictions with observational data on the diversity between cool-core (CC) and non-cool-core (NCC) clusters. Our simulations include the effects of stellar and active galactic nucleus (AGN) feedback and are based on an improved version of the smoothed particle hydrodynamics code GADGET-3, which ameliorates gas mixing and better captures gas-dynamical instabilities by including a suitable artificial thermal diffusion. In this Letter, we focus our analysis on the entropy profiles, the primary diagnostic we used to classify the degree of cool-coreness of clusters, and the iron profiles. In keeping with observations, our simulated clusters display a variety of behaviors in entropy profiles: they range from steadily decreasing profiles at small radii, characteristic of CC systems, to nearly flat core isentropic profiles, characteristic of NCC systems. Using observational criteria to distinguish between the two classes of objects, we find that they occur in similar proportions in both simulations and observations. Furthermore, we also find that simulated CC clusters have profiles of iron abundance that are steeper than those of NCC clusters, which is also in agreement with observational results. We show that the capability of our simulations to generate a realistic CC structure in the cluster population is due to AGN feedback and artificial thermal diffusion: their combined action allows us to naturally distribute the energy extracted from super-massive black holes and to compensate for the radiative losses of low-entropy gas with short cooling time residing in the cluster core.

  19. Raspberry Pi super cluster

    CERN Document Server

    Dennis, Andrew K

    2013-01-01

    This book follows a step-by-step, tutorial-based approach which will teach you how to develop your own super cluster using Raspberry Pi computers quickly and efficiently.Raspberry Pi Super Cluster is an introductory guide for those interested in experimenting with parallel computing at home. Aimed at Raspberry Pi enthusiasts, this book is a primer for getting your first cluster up and running.Basic knowledge of C or Java would be helpful but no prior knowledge of parallel computing is necessary.

  20. Cluster modular autocontenido

    OpenAIRE

    2009-01-01

    Desde hace años es común en organizaciones educativas y de investigación el desarrollo de actividades que requieren grandes capacidades de cálculo. La solución más común a estas necesidades es la compra o construcción de un cluster HPC (High Performance Computing), pero construir un cluster acarrea problemas y costos inesperados problemas al momento de utilizarlo y mantenerlo en operaciones. Nuestro proyecto busca desarrollar y documentar técnicas para construir un cluster HPC que sea fácilme...

  1. Extending Beowulf Clusters

    Science.gov (United States)

    Steinwand, Daniel R.; Maddox, Brian; Beckmann, Tim; Hamer, George

    2003-01-01

    Beowulf clusters can provide a cost-effective way to compute numerical models and process large amounts of remote sensing image data. Usually a Beowulf cluster is designed to accomplish a specific set of processing goals, and processing is very efficient when the problem remains inside the constraints of the original design. There are cases, however, when one might wish to compute a problem that is beyond the capacity of the local Beowulf system. In these cases, spreading the problem to multiple clusters or to other machines on the network may provide a cost-effective solution.

  2. Introduction to cluster dynamics

    CERN Document Server

    Reinhard, Paul-Gerhard

    2008-01-01

    Clusters as mesoscopic particles represent an intermediate state of matter between single atoms and solid material. The tendency to miniaturise technical objects requires knowledge about systems which contain a ""small"" number of atoms or molecules only. This is all the more true for dynamical aspects, particularly in relation to the qick development of laser technology and femtosecond spectroscopy. Here, for the first time is a highly qualitative introduction to cluster physics. With its emphasis on cluster dynamics, this will be vital to everyone involved in this interdisciplinary subje

  3. ClusterAlive

    Science.gov (United States)

    Caruso, G.; Arezzini, S.; Ciampa, A.; Formuso, A.; Mazzoni, E.

    2015-12-01

    INFN-Pisa Scientific Computing Center is working from many years both in GRID and HPC computing. The monitoring and managing tools have been key components of the center's successful operation. The lessons learned from the use of standard tools, such as Ganglia, have been starting points for the development of new tools specific for our infrastructure. In this note we will illustrate the integration of many different monitoring tools in one single platform called ClusterAlive. Aim of ClusterAlive is to increase the HPC cluster performance and simplify maintenance operations, possibly in a proactive approach.

  4. From collisions to clusters

    DEFF Research Database (Denmark)

    Loukonen, Ville; Bork, Nicolai; Vehkamaki, Hanna

    2014-01-01

    -principles molecular dynamics collision simulations of (sulphuric acid)1(water)0, 1 + (dimethylamine) → (sulphuric acid)1(dimethylamine)1(water)0, 1 cluster formation processes. The simulations indicate that the sticking factor in the collisions is unity: the interaction between the molecules is strong enough...... to overcome the possible initial non-optimal collision orientations. No post-collisional cluster break up is observed. The reasons for the efficient clustering are (i) the proton transfer reaction which takes place in each of the collision simulations and (ii) the subsequent competition over the proton...

  5. Negotiating Cluster Boundaries

    DEFF Research Database (Denmark)

    Giacomin, Valeria

    2017-01-01

    Palm oil was introduced to Malay(si)a as an alternative to natural rubber, inheriting its cluster organizational structure. In the late 1960s, Malaysia became the world’s largest palm oil exporter. Based on archival material from British colonial institutions and agency houses, this paper focuses...... on the governance dynamics that drove institutional change within this cluster during decolonization. The analysis presents three main findings: (i) cluster boundaries are defined by continuous tug-of-war style negotiations between public and private actors; (ii) this interaction produces institutional change...

  6. Combining cluster number counts and galaxy clustering

    Science.gov (United States)

    Lacasa, Fabien; Rosenfeld, Rogerio

    2016-08-01

    The abundance of clusters and the clustering of galaxies are two of the important cosmological probes for current and future large scale surveys of galaxies, such as the Dark Energy Survey. In order to combine them one has to account for the fact that they are not independent quantities, since they probe the same density field. It is important to develop a good understanding of their correlation in order to extract parameter constraints. We present a detailed modelling of the joint covariance matrix between cluster number counts and the galaxy angular power spectrum. We employ the framework of the halo model complemented by a Halo Occupation Distribution model (HOD). We demonstrate the importance of accounting for non-Gaussianity to produce accurate covariance predictions. Indeed, we show that the non-Gaussian covariance becomes dominant at small scales, low redshifts or high cluster masses. We discuss in particular the case of the super-sample covariance (SSC), including the effects of galaxy shot-noise, halo second order bias and non-local bias. We demonstrate that the SSC obeys mathematical inequalities and positivity. Using the joint covariance matrix and a Fisher matrix methodology, we examine the prospects of combining these two probes to constrain cosmological and HOD parameters. We find that the combination indeed results in noticeably better constraints, with improvements of order 20% on cosmological parameters compared to the best single probe, and even greater improvement on HOD parameters, with reduction of error bars by a factor 1.4-4.8. This happens in particular because the cross-covariance introduces a synergy between the probes on small scales. We conclude that accounting for non-Gaussian effects is required for the joint analysis of these observables in galaxy surveys.

  7. The "best balance" allocation led to optimal balance in cluster-controlled trials.

    NARCIS (Netherlands)

    Hoop, E. de; Teerenstra, S.; Gaal, B. van; Moerbeek, M.; Borm, G.F.

    2012-01-01

    OBJECTIVE: Balance of prognostic factors between treatment groups is desirable because it improves the accuracy, precision, and credibility of the results. In cluster-controlled trials, imbalance can easily occur by chance when the number of cluster is small. If all clusters are known at the start o

  8. 60 micron luminosity evolution of rich clusters of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, D.M.; Rieke, G.H. (Steward Observatory, Tucson, AZ (USA))

    1990-10-01

    The average 60-micron flux has been determined for a collection of optically selected galaxy clusters at redshifts ranging from 0.30 to 0.92. The result, 26 mJy per cluster, represents the faintest flux determination known of using the IRAS data base. The flux from this set of clusters has been compared to the 60-micron flux from a sample of nearby galaxy clusters. It is found that the far-infrared luminosity evolution in cluster galaxies can be no more than a factor of 1.7 from z = 0.4 to the present epoch. This upper limit is close to the evolution predicted for simple aging of the stellar populations. Additional processes such as mergers, cannibalism, or enhanced rates of starbursts appear to occur at a low enough level that they have little influence on the far-infrared emission from clusters over this redshift range. 38 refs.

  9. The rise of operon-like gene clusters in plants.

    Science.gov (United States)

    Boycheva, Svetlana; Daviet, Laurent; Wolfender, Jean-Luc; Fitzpatrick, Teresa B

    2014-07-01

    Gene clusters are common features of prokaryotic genomes also present in eukaryotes. Most clustered genes known are involved in the biosynthesis of secondary metabolites. Although horizontal gene transfer is a primary source of prokaryotic gene cluster (operon) formation and has been reported to occur in eukaryotes, the predominant source of cluster formation in eukaryotes appears to arise de novo or through gene duplication followed by neo- and sub-functionalization or translocation. Here we aim to provide an overview of the current knowledge and open questions related to plant gene cluster functioning, assembly, and regulation. We also present potential research approaches and point out the benefits of a better understanding of gene clusters in plants for both fundamental and applied plant science.

  10. The dynamics of cavity clusters in ultrasonic (vibratory) cavitation erosion

    DEFF Research Database (Denmark)

    Hansson, I.; Mørch, Knud Aage

    1980-01-01

    The erosion of solids caused by cavitating liquids is a result of the concerted collapse of clusters of cavities. In vibratory cavitation equipment the clusters grow and collapse adjacent to a solid surface and are typically of hemispherical or cylindrical form. In the present paper the collapse...... process of these clusters is described and the collapse equations are developed and solved. The theoretical results are compared with results from high-speed photography of the clusters and with the initial stages of cavitation erosion on metal specimens. Experimental and theoretical results show...... the ambient pressure. Therefore the collapse velocity of the individual cavities increases towards the cluster center, which explains that the erosion, being caused by the individual cavities, occurs predominantly in this region. Likewise, the pressure increase at the cluster boundary explains why materials...

  11. Hox cluster organization in the jawless vertebrate Petromyzon marinus.

    Science.gov (United States)

    Force, Allan; Amores, Angel; Postlethwait, John H

    2002-04-15

    Large-scale gene amplifications may have facilitated the evolution of morphological innovations that accompanied the origin of vertebrates. This hypothesis predicts that the genomes of extant jawless fish, scions of deeply branching vertebrate lineages, should bear a record of these events. Previous work suggests that nonvertebrate chordates have a single Hox cluster, but that gnathostome vertebrates have four or more Hox clusters. Did the duplication events that produced multiple vertebrate Hox clusters occur before or after the divergence of agnathan and gnathostome lineages? Can investigation of lamprey Hox clusters illuminate the origins of the four gnathostome Hox clusters? To approach these questions, we cloned and sequenced 13 Hox cluster genes from cDNA and genomic libraries in the lamprey, Petromyzon marinus. The results suggest that the lamprey has at least four Hox clusters and support the model that gnathostome Hox clusters arose by a two-round-no-cluster-loss mechanism, with tree topology [(AB)(CD)]. A three-round model, however, is not rigorously excluded by the data and, for this model, the tree topologies [(D(C(AB))] and [(C(D(AB))] are most parsimonious. Gene phylogenies suggest that at least one Hox cluster duplication occurred in the lamprey lineage after it diverged from the gnathostome lineage. The results argue against two or more rounds of duplication before the divergence of agnathan and gnathostome vertebrates. If Hox clusters were duplicated in whole-genome duplication events, then these data suggest that, at most, one whole genome duplication occurred before the evolution of vertebrate developmental innovations.

  12. Nonrandom patterns of genetic admixture expose the complex historical hybrid origin of unisexual leaf beetle species in the genus Calligrapha.

    Science.gov (United States)

    Montelongo, Tinguaro; Gómez-Zurita, Jesús

    2015-01-01

    Many unisexual animal lineages supposedly arose from hybridization. However, support for their putative hybrid origins mostly comes from indirect methodologies, which are rarely confirmatory. Here we provide compelling data indicating that tetraploid unisexual Calligrapha are true genetic mosaics obtained via analysis of mitochondrial DNA (mtDNA) and allelic variation and coalescence times for three single-copy nuclear genes (CPS, HARS, and Wg) in five of six unisexual Calligrapha and a representative sample of bisexual species. Nuclear allelic diversity in unisexuals consistently segregates in the gene pools of at least two but up to three divergent bisexual species, interpreted as putative parentals of interspecific hybridization crosses. Interestingly, their mtDNA diversity derives from an additional yet undiscovered older evolutionary lineage that is possibly the same for all independently originated unisexual species. One possibly extinct species transferred its mtDNA to several evolutionary lineages in a wave of hybridization events during the Pliocene, whereby descendant species retained a polymorphic mtDNA constitution. Recent hybridizations, in the Pleistocene and always involving females with the old introgressed mtDNA, seemingly occurred in the lineages leading to unisexual species, decoupling mtDNA introgression (and inferences derived from these data, such as timing and parentage) from subsequent acquisition of the new reproductive mode. These results illuminate an unexpected complexity in possible routes to animal unisexuality, with implications for the interpretation of ancient unisexuality. If the origin of unisexuality requires a mechanism where (1) hybridization is a necessary but insufficient condition and (2) multiple bouts of hybridization involving more than two divergent lineages are required, then the origins of several classical unisexual systems may have to be reassessed.

  13. Nonrandom chromosomal abnormalities in acute nonlymphocytic leukemia in patients treated for Hodgkin disease and non-Hodgkin lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, J.D.; Golomb, H.M.; Vardiman, J.

    1977-11-01

    Chromosomal analyses of myeloid cells were performed on ten patients who had acute nonlymphocytic leukemia (ANLL) following treatment for malignant lymphoma. Seven patients had Hodgkin disease and three had non-Hodgkin lymphoma, poorly differentiated lymphocytic type. Six patients were treated with radiotherapy and chemotherapy; two had radiotherapy only, and two chemotherapy only. The median time between diagnosis of lymphoma and subsequent leukemia was 58 mo. Four patients had the blast phase of a myeloproliferative syndrome, four had acute myelogenous leukemia, one had acute promyelocytic leukemia, and the tenth, erythroleukemia. None of four patients whose leukemia was treated with intensive chemotherapy responded. Every patient had an abnormal karyotype. Seven of the patients showed hypodiploid cell lines, two a pseudodiploid, and one a hyperdiploid cell line. Cells from every patient except one were lacking a B chromosome; in eight, this could be identified as a No. 5. Five of nine patients were lacking a No. 7. Loss or rearrangement of No. 17 was found in four and of Nos. 6 or 8 in three patients. Many of the karyotypes were bizarre, with marker chromosomes and minute chromosomes. The karyotypic pattern seen in these patients showed no correlation with the nature of the original lymphoma, the type of leukemia, or the therapy used. The chromosomal pattern of hypodiploid cell lines found in ANLL that arose de novo was similar to that occurring in treated lymphoma. However, in ANLL de novo, less than half of the patients had fewer than 46 chromosomes, and less than 10% had fewer than 45 chromosomes. In this study, 70% of the patients had fewer than 46 and 40% had fewer than 45 chromosomes. The critical question thus concerns the factors, as yet unknown, that predispose to the development of hypodiploid modal numbers in ANLL in lymphoma.

  14. Evolution of clustered storage

    CERN Document Server

    CERN. Geneva; Van de Vyvre, Pierre

    2007-01-01

    The session actually featured two presentations: * Evolution of clustered storage by Lance Hukill, Quantum Corporation * ALICE DAQ - Usage of a Cluster-File System: Quantum StorNext by Pierre Vande Vyvre, CERN-PH the second one prepared at short notice by Pierre (thanks!) to present how the Quantum technologies are being used in the ALICE experiment. The abstract to Mr Hukill's follows. Clustered Storage is a technology that is driven by business and mission applications. The evolution of Clustered Storage solutions starts first at the alignment between End-users needs and Industry trends: * Push-and-Pull between managing for today versus planning for tomorrow * Breaking down the real business problems to the core applications * Commoditization of clients, servers, and target devices * Interchangeability, Interoperability, Remote Access, Centralized control * Oh, and yes, there is a budget and the "real world" to deal with This presentation will talk through these needs and trends, and then ask the question, ...

  15. Improved graph clustering

    Science.gov (United States)

    2013-01-01

    on Facebook , one would like to detect tightly connected communities, which is useful for subsequent tasks like customized recommendation and... advertisement . Graphs in modern applications have several characteristics that complicate graph clustering: • Small density gap: the edge density across

  16. Clustering of Emerging Flux

    Science.gov (United States)

    Ruzmaikin, A.

    1997-01-01

    Observations show that newly emerging flux tends to appear on the Solar surface at sites where there is flux already. This results in clustering of solar activity. Standard dynamo theories do not predict this effect.

  17. How Clusters Work

    Science.gov (United States)

    Technology innovation clusters are geographic concentrations of interconnected companies, universities, and other organizations with a focus on environmental technology. They play a key role in addressing the nation’s pressing environmental problems.

  18. Clustering in Ethiopia

    African Journals Online (AJOL)

    Information Systems (GIS) that can process the data may not be available and accessible where ... Methods: An example of space-time clustering of malaria cases around a dam in Ethiopia (106 .... was prepared for publication using mapping.

  19. APROACHES TOWARDS CLUSTER ANALYSIS

    National Research Council Canada - National Science Library

    Manuela Tvaronaviciene; Kristina Razminiene; Leonardo Piccinetti

    2015-01-01

    .... The findings indicate that case study is used in many articles refering to cluster research. Other methods, such as analysis, interview, survey, research, equation and others are used to support case study...

  20. Parallel Wolff Cluster Algorithms

    Science.gov (United States)

    Bae, S.; Ko, S. H.; Coddington, P. D.

    The Wolff single-cluster algorithm is the most efficient method known for Monte Carlo simulation of many spin models. Due to the irregular size, shape and position of the Wolff clusters, this method does not easily lend itself to efficient parallel implementation, so that simulations using this method have thus far been confined to workstations and vector machines. Here we present two parallel implementations of this algorithm, and show that one gives fairly good performance on a MIMD parallel computer.

  1. Magnetic cluster excitations

    Science.gov (United States)

    Furrer, Albert; Waldmann, Oliver

    2013-01-01

    Magnetic clusters, i.e., assemblies of a finite number (between two or three and several hundred) of interacting spin centers which are magnetically decoupled from their environment, can be found in many materials ranging from inorganic compounds and magnetic molecules to artificial metal structures formed on surfaces and metalloproteins. Their magnetic excitation spectra are determined by the nature of the spin centers and of the magnetic interactions, and the particular arrangement of the mutual interaction paths between the spin centers. Small clusters of up to four magnetic ions are ideal model systems in which to examine the fundamental magnetic interactions, which are usually dominated by Heisenberg exchange, but often complemented by anisotropic and/or higher-order interactions. In large magnetic clusters, which may potentially deal with a dozen or more spin centers, there is the possibility of novel many-body quantum states and quantum phenomena. In this review the necessary theoretical concepts and experimental techniques to study the magnetic cluster excitations and the resulting characteristic magnetic properties are introduced, followed by examples of small clusters, demonstrating the enormous amount of detailed physical information that can be retrieved. The current understanding of the excitations and their physical interpretation in the molecular nanomagnets which represent large magnetic clusters is then presented, with a section devoted to the subclass of single-molecule magnets, distinguished by displaying quantum tunneling of the magnetization. Finally, there is a summary of some quantum many-body states which evolve in magnetic insulators characterized by built-in or field-induced magnetic clusters. The review concludes by addressing future perspectives in the field of magnetic cluster excitations.

  2. Cauchy cluster process

    DEFF Research Database (Denmark)

    Ghorbani, Mohammad

    2013-01-01

    In this paper we introduce an instance of the well-know Neyman–Scott cluster process model with clusters having a long tail behaviour. In our model the offspring points are distributed around the parent points according to a circular Cauchy distribution. Using a modified Cramér-von Misses test st...... statistic and the simulated pointwise envelopes it is shown that this model fits better than the Thomas process to the frequently analyzed long-leaf pine data-set....

  3. Globular clusters with Gaia

    Science.gov (United States)

    Pancino, E.; Bellazzini, M.; Giuffrida, G.; Marinoni, S.

    2017-01-01

    The treatment of crowded fields in Gaia data will only be a reality in a few years from now. In particular, for globular clusters, only the end-of-mission data (public in 2022-2023) will have the necessary full crowding treatment and will reach sufficient quality for the faintest stars. As a consequence, the work on the deblending and decontamination pipelines is still ongoing. We describe the present status of the pipelines for different Gaia instruments, and we model the end-of-mission crowding errors on the basis of available information. We then apply the nominal post-launch Gaia performances, appropriately worsened by the estimated crowding errors, to a set of 18 simulated globular clusters with different concentration, distance, and field contamination. We conclude that there will be 103-104 stars with astrometric performances virtually untouched by crowding (contaminated by <1 mmag) in the majoritiy of clusters. The most limiting factor will be field crowding, not cluster crowding: the most contaminated clusters will only contain 10-100 clean stars. We also conclude that: (i) the systemic proper motions and parallaxes will be determined to 1% or better up to ≃15 kpc, and the nearby clusters will have radial velocities to a few km s-1 ; (ii) internal kinematics will be of unprecendented quality, cluster masses will be determined to ≃10% up to 15 kpc and beyond, and it will be possible to identify differences of a few km s-1 or less in the kinematics (if any) of cluster sub-populations up to 10 kpc and beyond; (iii) the brightest stars (V≃17 mag) will have space-quality, wide-field photometry (mmag errors), and all Gaia photometry will have 1-3% errors on the absolute photometric calibration.

  4. Cosmography with Galaxy Clusters

    CERN Document Server

    Soares-Santos, M; La Barbera, F; Lopes, P A A; Annis, J

    2008-01-01

    In the present work we focus on future experiments using cluster abundance observations to constraint the Dark Energy equation of state parameter, w. To obtain tight constraints from this kind of experiment, a reliable sample of galaxy clusters must be obtained from deep and wide-field images. We therefore present the computational environment (2DPHOT) that allow us to build the galaxy catalog from the images and the Voronoi Tessellation cluster finding algorithm that we use to identify the galaxy clusters on those catalogs. To test our pipeline with data similar in quality to what will be gathered by future wide field surveys, we process images from the Deep fields obtained as part of the LEGACY Survey (four fields of one square degree each, in five bands, with depth up to r'=25). We test our cluster finder by determining the completeness and purity of the finder when applied to mock galaxy catalogs made for the Dark Energy Survey cluster finder comparison project by Risa Wechsler and Michael Busha. This pro...

  5. Galaxy cluster's rotation

    CERN Document Server

    Manolopoulou, Maria

    2016-01-01

    We study the possible rotation of cluster galaxies, developing, testing and applying a novel algorithm which identifies rotation, if such does exits, as well as its rotational centre, its axis orientation, rotational velocity amplitude and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte-Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z<~0.1 with member galaxies selected from the SDSS DR10 spectroscopic database. We find that ~35% of our clusters are rotating when using a set of strict criteria, while loosening the criteria we find this fraction increasing to ~48%. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation that the significance and strength of their...

  6. Cluster functional renormalization group

    Science.gov (United States)

    Reuther, Johannes; Thomale, Ronny

    2014-01-01

    Functional renormalization group (FRG) has become a diverse and powerful tool to derive effective low-energy scattering vertices of interacting many-body systems. Starting from a free expansion point of the action, the flow of the RG parameter Λ allows us to trace the evolution of the effective one- and two-particle vertices towards low energies by taking into account the vertex corrections between all parquet channels in an unbiased fashion. In this work, we generalize the expansion point at which the diagrammatic resummation procedure is initiated from a free UV limit to a cluster product state. We formulate a cluster FRG scheme where the noninteracting building blocks (i.e., decoupled spin clusters) are treated exactly, and the intercluster couplings are addressed via RG. As a benchmark study, we apply our cluster FRG scheme to the spin-1/2 bilayer Heisenberg model (BHM) on a square lattice where the neighboring sites in the two layers form the individual two-site clusters. Comparing with existing numerical evidence for the BHM, we obtain reasonable findings for the spin susceptibility, the spin-triplet excitation energy, and quasiparticle weight even in coupling regimes close to antiferromagnetic order. The concept of cluster FRG promises applications to a large class of interacting electron systems.

  7. Design and baseline findings of a multi-site non-randomized evaluation of the effect of a health programme on microfinance clients in India.

    Science.gov (United States)

    Saha, Somen

    2013-10-12

    Microfinance is the provision of financial services for the poor. Health program through microfinance has the potential to address several access barriers to health. We report the design and baseline findings of a multi-site non-randomized evaluation of the effect of a health program on the members of two microfinance organizations from Karnataka and Gujarat states of India. Villages identified for roll-out of health services with microfinance were pair-matched with microfinance only villages. A quantitative survey at inception and twelve months post health intervention compare the primary outcome (incidence of childhood diarrhea), and secondary outcome (place of last delivery, toilet at home, and out-of-pocket expenditure on treatment). At baseline, the intervention and comparison communities were similar except for out-of-pocket expenditure on health. Low reported use of toilet at home indicates the areas are heading towards a sanitation crisis. This should be an area of program priority for the microfinance organizations. While respondents primarily rely on their savings for meeting treatment expenditure, borrowing from friends, relatives, and money-lenders remains other important source of meeting treatment expenditure in the community. Programs need to prioritize steps to ensure awareness about national health insurance schemes, entitlement to increase service utilization, and developing additional health financing safety nets for financing outpatient care, that are responsible for majority of health-debt. Finally we discuss implications of such programs for national policy makers.

  8. A Complex Multiherbal Regimen Based on Ayurveda Medicine for the Management of Hepatic Cirrhosis Complicated by Ascites: Nonrandomized, Uncontrolled, Single Group, Open-Label Observational Clinical Study.

    Science.gov (United States)

    Patel, Manish V; Patel, Kalapi B; Gupta, Shivenarain; Michalsen, Andreas; Stapelfeldt, Elmar; Kessler, Christian S

    2015-01-01

    Hepatic cirrhosis is one of the leading causes of death worldwide, especially if complicated by ascites. This chronic condition can be related to the classical disease entity jalodara in Traditional Indian Medicine (Ayurveda). The present paper aims to evaluate the general potential of Ayurvedic therapy for overall clinical outcomes in hepatic cirrhosis complicated by ascites (HCcA). In form of a nonrandomized, uncontrolled, single group, open-label observational clinical study, 56 patients fulfilling standardized diagnostic criteria for HCcA were observed during their treatment at the P. D. Patel Ayurveda Hospital, Nadiad, India. Based on Ayurvedic tradition, a standardized treatment protocol was developed and implemented, consisting of oral administration of single and compound herbal preparations combined with purificatory measures as well as dietary and lifestyle regimens. The outcomes were assessed by measuring liver functions through specific clinical features and laboratory parameters and by evaluating the Child-Pugh prognostic grade score. After 6 weeks of treatment and a follow-up period of 18 weeks, the outcomes showed statistically significant and clinically relevant improvements. Further larger and randomized trials on effectiveness, safety, and quality of the Ayurvedic approach in the treatment of HCcA are warranted to support these preliminary findings.

  9. Correlation and prediction of partition coefficient using nonrandom two-liquid segment activity coefficient model for solvent system selection in counter-current chromatography separation.

    Science.gov (United States)

    Ren, Da-Bing; Yang, Zhao-Hui; Liang, Yi-Zeng; Ding, Qiong; Chen, Chen; Ouyang, Mei-Lan

    2013-08-02

    Selection of a suitable solvent system is the first and foremost step for a successful counter-current chromatography (CCC) separation. In this paper, a thermodynamic model, nonrandom two-liquid segment activity coefficient model (NRTL-SAC) which uses four types of conceptual segments to describe the effective surface interactions for each solvent and solute molecule, was employed to correlate and predict the partition coefficients (K) of a given compound in a specific solvent system. Then a suitable solvent system was selected according to the predicted partition coefficients. Three solvent system families, heptane/methanol/water, heptane/ethyl acetate/methanol/water (Arizona) and hexane/ethyl acetate/methanol/water, and several solutes were selected to investigate the effectiveness of the NRTL-SAC model for predicting the partition coefficients. Comparison between experimental results and predicted results showed that the NRTL-SAC model is of potential for estimating the K value of a given compound. Also a practical separation case on magnolol and honokiol suggests the NRTL-SAC model is effective, reliable and practical for the purpose of predicting partition coefficients and selecting a suitable solvent system for CCC separation. Copyright © 2013. Published by Elsevier B.V.

  10. A Complex Multiherbal Regimen Based on Ayurveda Medicine for the Management of Hepatic Cirrhosis Complicated by Ascites: Nonrandomized, Uncontrolled, Single Group, Open-Label Observational Clinical Study

    Directory of Open Access Journals (Sweden)

    Manish V. Patel

    2015-01-01

    Full Text Available Hepatic cirrhosis is one of the leading causes of death worldwide, especially if complicated by ascites. This chronic condition can be related to the classical disease entity jalodara in Traditional Indian Medicine (Ayurveda. The present paper aims to evaluate the general potential of Ayurvedic therapy for overall clinical outcomes in hepatic cirrhosis complicated by ascites (HCcA. In form of a nonrandomized, uncontrolled, single group, open-label observational clinical study, 56 patients fulfilling standardized diagnostic criteria for HCcA were observed during their treatment at the P. D. Patel Ayurveda Hospital, Nadiad, India. Based on Ayurvedic tradition, a standardized treatment protocol was developed and implemented, consisting of oral administration of single and compound herbal preparations combined with purificatory measures as well as dietary and lifestyle regimens. The outcomes were assessed by measuring liver functions through specific clinical features and laboratory parameters and by evaluating the Child-Pugh prognostic grade score. After 6 weeks of treatment and a follow-up period of 18 weeks, the outcomes showed statistically significant and clinically relevant improvements. Further larger and randomized trials on effectiveness, safety, and quality of the Ayurvedic approach in the treatment of HCcA are warranted to support these preliminary findings.

  11. Estimating the treatment effect from non-randomized studies: The example of reduced intensity conditioning allogeneic stem cell transplantation in hematological diseases

    Directory of Open Access Journals (Sweden)

    Resche-Rigon Matthieu

    2012-08-01

    Full Text Available Abstract Background In some clinical situations, for which RCT are rare or impossible, the majority of the evidence comes from observational studies, but standard estimations could be biased because they ignore covariates that confound treatment decisions and outcomes. Methods Three observational studies were conducted to assess the benefit of Allo-SCT in hematological malignancies of multiple myeloma, follicular lymphoma and Hodgkin’s disease. Two statistical analyses were performed: the propensity score (PS matching approach and the inverse probability weighting (IPW approach. Results Based on PS-matched samples, a survival benefit in MM patients treated by Allo-SCT, as compared to similar non-allo treated patients, was observed with an HR of death at 0.35 (95%CI: 0.14-0.88. Similar results were observed in HD, 0.23 (0.07-0.80 but not in FL, 1.28 (0.43-3.77. Estimated benefits of Allo-SCT for the original population using IPW were erased in HR for death at 0.72 (0.37-1.39 for MM patients, 0.60 (0.19-1.89 for HD patients, and 2.02 (0.88-4.66 for FL patients. Conclusion Differences in estimated benefits rely on whether the underlying population to which they apply is an ideal randomized experimental population (PS or the original population (IPW. These useful methods should be employed when assessing the effects of innovative treatment in non-randomized experiments.

  12. Clinical Pathways Based on Integrative Medicine in Chinese Hospitals Improve Treatment Outcomes for Patients with Acute Myocardial Infarction: A Multicentre, Nonrandomized Historically Controlled Trial

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2012-01-01

    Full Text Available Objective. To determine the impact of an integrative medicine clinical pathways (CPs on the length of in-hospital stay and on outcomes for patients with acute myocardial infarction (AMI. Methods. A multicenter nonrandomized controlled trial enrolling 197 consecutive patients with AMI at eight urban TCM hospitals was conducted between 1 January 2010 and 31 October 2010. These patients were enrolled in the interventional group after the CPs had been implemented. The control group included 405 patients with AMI from eight hospitals; these patients were treated between 1 January 2008 and 31 December 2009, before the CPs were implemented. Outcome measures were the length of hospital stay costs of medical care, and major cardiovascular events (MACEs during hospitalization. Results. Compared with the control group, the patients in intervention group had a shorter length of hospital stay (9.2±4.2 days versus 12.7±8.6 days, P<0.05, and reduced healthcare costs in hospital (46365.7±18266.9 versus 52866.0±35404.4, P<0.05. There were statistically significant differences in MACE between the two groups during the hospitalization period (2.5% versus 6.9%, P=0.03. Conclusion. These data suggest that the development and implementation of the clinical pathways based in Integrative Medicine could further improve quality of care and outcome for patients with AMI.

  13. Correlation of Critical Loci for Water-Hydrocarbon Binary Systems by EOS Based on the Multi-Fluid Nonrandom Lattice Theory

    Institute of Scientific and Technical Information of China (English)

    Hun; Yong; SHIN; Hwayong; KIM; 等

    2002-01-01

    Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories remains as a difficults thermodynamic topics to date.In the present work,a computational efforts were made for representing various types of critical loci of binary water with hydrocarbon systems showing Type Ⅱ and Type Ⅲ phase behavior by an elementary equation of state[called multi-fluid nonrandom lattice fluid EOS(MF-NLF EOS)]based on the lattice statistical mechanical theory.The model EOS requires two molecular parameters which representing molecular size and interaction energy for a pure component and single adjustable interaction energy parameter for binary mixtures.Critical temperature and pressure data were used to obtain molecular size parameter and vapor pressure data were used to obtain interaction energy parameter.The MF-NLF EOS model adapted in the present study correlated quantitatively well the critical loci of various binary water with hydrocarbon systems.

  14. An Ant Colony Optimization algorithm for solving the fixed destination multi-depot multiple traveling salesman problem with non-random parameters

    Science.gov (United States)

    Ramadhani, T.; Hertono, G. F.; Handari, B. D.

    2017-07-01

    The Multiple Traveling Salesman Problem (MTSP) is the extension of the Traveling Salesman Problem (TSP) in which the shortest routes of m salesmen all of which start and finish in a single city (depot) will be determined. If there is more than one depot and salesmen start from and return to the same depot, then the problem is called Fixed Destination Multi-depot Multiple Traveling Salesman Problem (MMTSP). In this paper, MMTSP will be solved using the Ant Colony Optimization (ACO) algorithm. ACO is a metaheuristic optimization algorithm which is derived from the behavior of ants in finding the shortest route(s) from the anthill to a form of nourishment. In solving the MMTSP, the algorithm is observed with respect to different chosen cities as depots and non-randomly three parameters of MMTSP: m, K, L, those represents the number of salesmen, the fewest cities that must be visited by a salesman, and the most number of cities that can be visited by a salesman, respectively. The implementation is observed with four dataset from TSPLIB. The results show that the different chosen cities as depots and the three parameters of MMTSP, in which m is the most important parameter, affect the solution.

  15. The nuclear position of pericentromeric DNA of chromosome 11 appears to be random in G0 and non-random in G1 human lymphocytes.

    Science.gov (United States)

    Hulspas, R; Houtsmuller, A B; Krijtenburg, P J; Bauman, J G; Nanninga, N

    1994-07-01

    The nuclear topography of pericentromeric DNA of chromosome 11 was analyzed in G0 (nonstimulated) and G1 [phytohemagglutinin (PHA) stimulated] human lymphocytes by confocal microscopy. In addition to the nuclear center, the centrosome was used as a second point of reference in the three-dimensional (3D) analysis. Pericentromeric DNA of chromosome 11 and the centrosome were labeled using a combination of fluorescent in situ hybridization (FISH) and immunofluorescence. To preserve the 3D morphology of the cells, these techniques were performed on whole cells in suspension. Three-dimensional images of the cells were analyzed with a recently developed 3D software program (Interactive Measurement of Axes and Positioning in 3 Dimensions). The distribution of the chromosome 11 centromeres appeared to be random during the G0 stage but clearly non-random during the G1 stage, when the nuclear center was used as a reference point. Further statistical analysis of the G1 cells revealed that the centromeres were randomly distributed in a shell underlying the nuclear membrane. A topographical relationship between the centrosome and the centromeres appeared to be absent during the G0 and G1 stages of the cell cycle.

  16. Links between fear of humans, stress and survival support a non-random distribution of birds among urban and rural habitats.

    Science.gov (United States)

    Rebolo-Ifrán, Natalia; Carrete, Martina; Sanz-Aguilar, Ana; Rodríguez-Martínez, Sol; Cabezas, Sonia; Marchant, Tracy A; Bortolotti, Gary R; Tella, José L

    2015-09-08

    Urban endocrine ecology aims to understand how organisms cope with new sources of stress and maintain allostatic load to thrive in an increasingly urbanized world. Recent research efforts have yielded controversial results based on short-term measures of stress, without exploring its fitness effects. We measured feather corticosterone (CORTf, reflecting the duration and amplitude of glucocorticoid secretion over several weeks) and subsequent annual survival in urban and rural burrowing owls. This species shows high individual consistency in fear of humans (i.e., flight initiation distance, FID), allowing us to hypothesize that individuals distribute among habitats according to their tolerance to human disturbance. FIDs were shorter in urban than in rural birds, but CORTf levels did not differ, nor were correlated to FIDs. Survival was twice as high in urban as in rural birds and links with CORTf varied between habitats: while a quadratic relationship supports stabilizing selection in urban birds, high predation rates may have masked CORTf-survival relationship in rural ones. These results evidence that urban life does not constitute an additional source of stress for urban individuals, as shown by their near identical CORTf values compared with rural conspecifics supporting the non-random distribution of individuals among habitats according to their behavioural phenotypes.

  17. Cloning of ribosomal ITS PCR products creates frequent, non-random chimeric sequences – a test involving heterozygotes between Gymnopus dichrous taxa I and II

    Directory of Open Access Journals (Sweden)

    Karen W. Hughes

    2015-06-01

    Full Text Available Gymnopus dichrous exists in the southern Appalachians (USA as two distinct entities with essentially identical nuclear ribosomal ITS1 sequences but differing ITS2 and LSU sequences (for convenience, called G. dichrous I and II. F1 ITS heterozygotes between the two are routinely collected from nature. Cloning of ITS PCR products from F1 heterozygotes produced sequences of both parental haplotypes but also numerous chimeric sequences (21.9%. The location of template switching was non-random leading to recovery of the same chimera several times and the chimeric region varied from 45bp to 300bp. By comparison, single-basidiospore isolates from heterozygote F1 fruitbodies showed no recombinant haplotypes within the ITS + LSU span and clones derived from P1 homozygotes were identical to the P1 parent. Thus, chimeric sequences are likely an artifact of the PCR-cloning process and not a consequence of natural recombination events found in nature, nor are they due to hidden existing variation within the ribosomal repeat. Chimeras and PCR-induced mutations are common in cloned PCR products and may result in incorrect sequence information in public databases.

  18. Additive Complex Ayurvedic Treatment in Patients with Fibromyalgia Syndrome Compared to Conventional Standard Care Alone: A Nonrandomized Controlled Clinical Pilot Study (KAFA Trial

    Directory of Open Access Journals (Sweden)

    Christian S. Kessler

    2013-01-01

    Full Text Available Background. Fibromyalgia (FMS is a challenging condition for health care systems worldwide. Only limited trial data is available for FMS for outcomes of complex treatment interventions of complementary and integrative (CIM approaches. Methods. We conducted a controlled, nonrandomized feasibility study that compared outcomes in 21 patients treated with Ayurveda with those of 11 patients treated with a conventional approach at the end of a two-week inpatient hospital stay. Primary outcome was the impact of fibromyalgia on patients as assessed by the FIQ. Secondary outcomes included scores of pain intensity, pain perception, depression, anxiety, and quality of sleep. Follow-up assessments were done after 6 months. Results. At 2 weeks, there were comparable and significant improvements in the FIQ and for most of secondary outcomes in both groups with no significant in-between-group differences. The beneficial effects for both treatment groups were partly maintained for the main outcome and a number of secondary outcomes at the 6-month followup, again with no significant in-between-group differences. Discussion. The findings of this feasibility study suggest that Ayurvedic therapy is noninferior to conventional treatment in patients with severe FMS. Since Ayurveda was only used as add-on treatment, RCTs on Ayurveda alone are warranted to increase model validity. This trial is registered with NCT01389336.

  19. Effects of different frequencies (2-3 days/week) of aquatic therapy program in adults with chronic low back pain. A non-randomized comparison trial.

    Science.gov (United States)

    Baena-Beato, Pedro Angel; Arroyo-Morales, Manuel; Delgado-Fernández, Manuel; Gatto-Cardia, Maria Claudia; Artero, Enrique G

    2013-01-01

    To study the effects of an aquatic therapy program with different frequencies (2 vs 3 days per week) in chronic low back pain. [corrected] Non-randomized comparison trial. Sport and spa community health club. Fifty-four adults with chronic low back pain (48.9 ± 10.0 years). Eight-week aquatic therapy program. Pain (visual analog scale [VAS]), disability (Oswestry Disability Index), and quality of life (Short-Form Health Survey 36), body composition (weight, body mass index, body fat mass, body fat percentage, and skeletal muscle mass), and health-related fitness (sit and reach, handgrip strength, curl-up, Rockport 1-mile test). Both experimental groups presented significant improvements in low back pain and disability (P aquatic therapy program decrease levels of back pain and disability, increase quality of life, and improve health-related fitness in adults with chronic low back pain without effects in body composition. A dose-response effect was observed in some parameters, with greater benefits when exercising 3 days per week compared with 2 days. Wiley Periodicals, Inc.

  20. Bifidobacterium bifidum OLB6378 Simultaneously Enhances Systemic and Mucosal Humoral Immunity in Low Birth Weight Infants: A Non-Randomized Study

    Science.gov (United States)

    Tanaka, Katsunori; Tsukahara, Takamitsu; Yanagi, Takahide; Nakahara, Sayuri; Furukawa, Ouki; Tsutsui, Hidemi; Koshida, Shigeki

    2017-01-01

    Probiotic supplementation has been part of the discussion on methods to enhance humoral immunity. Administration of Bifidobacterium bifidum OLB6378 (OLB6378) reduced the incidence of late-onset sepsis in infants. In this non-randomized study, we aimed to determine the effect of administration of live OLB6378 on infants’ humoral immunity. Secondly, we tried to elucidate whether similar effects would be observed with administration of non-live OLB6378. Low birth weight (LBW) infants weighing 1500–2500 g were divided into three groups: Group N (no intervention), Group L (administered live OLB6378 concentrate), and Group H (administered non-live OLB6378 concentrate). The interventions were started within 48 h after birth and continued until six months of age. Serum immunoglobulin G (IgG) levels (IgG at one month/IgG at birth) were significantly higher in Group L than in Group N (p food ingredient, showed a more marked effect than the viable bacteria. PMID:28245626

  1. PROSPECTIVE OBSERVATIONAL, NON-RANDOMIZED, PARALLEL SEQUENCE STUDY FOR ASSESSMENT OF ADVERSE DRUG REACTIONS DUE TO CHEMOTHERAPEUTIC TREATMENT IN DIFFERENT TYPES OF CANCER PATIENTS

    Directory of Open Access Journals (Sweden)

    Mrugank B.P. * and Hareesha R.P.

    2013-01-01

    Full Text Available Objective: To assess incidence, causality, severity, predictability and preventability of adverse drug reactions (ADRs in hospitalised oncology patients.Materials and Methods: A prospective observational, non-randomized, parallel sequence study was conducted at Dr B. Borooah Cancer Institute (BBCI after getting an approval from human ethical committee. Patients hospitalised at BBCI from Aug 2010 to June 2011 were interviewed about symptoms related to their drug therapy. Patient medical records were also reviewed for data collection.Results: Total 663 patients associated with hospitalizations were interviewed. 899 ADRs were identified in total 410 (61.84% patients detected with ADRs. Most of all ADRs were moderate, predictable and not preventable. The most common ADRs were leucopenia, weakness, anorexia, alopecia, vomiting, diarrhoea, nausea, abdominal pain, fatigue, and anaemia in this study.Conclusions: For definite conclusion study should be repeated. Strict drug analyzing and in vivo study is also required if feasible.Key message: The process of defining and concluding about ADRs should be continuous and ongoing to keep a record of newly marketed drugs and medicinal products.

  2. Bifidobacterium bifidum OLB6378 Simultaneously Enhances Systemic and Mucosal Humoral Immunity in Low Birth Weight Infants: A Non-Randomized Study

    Directory of Open Access Journals (Sweden)

    Katsunori Tanaka

    2017-02-01

    Full Text Available Probiotic supplementation has been part of the discussion on methods to enhance humoral immunity. Administration of Bifidobacterium bifidum OLB6378 (OLB6378 reduced the incidence of late-onset sepsis in infants. In this non-randomized study, we aimed to determine the effect of administration of live OLB6378 on infants’ humoral immunity. Secondly, we tried to elucidate whether similar effects would be observed with administration of non-live OLB6378. Low birth weight (LBW infants weighing 1500–2500 g were divided into three groups: Group N (no intervention, Group L (administered live OLB6378 concentrate, and Group H (administered non-live OLB6378 concentrate. The interventions were started within 48 h after birth and continued until six months of age. Serum immunoglobulin G (IgG levels (IgG at one month/IgG at birth were significantly higher in Group L than in Group N (p < 0.01. Group H exhibited significantly higher serum IgG levels (p < 0.01 at one month of age and significantly higher intestinal secretory immunoglobulin A (SIgA levels (p < 0.05 at one and two months of age than Group N. No difference was observed in the mortality or morbidity between groups. Thus, OLB6378 administration in LBW infants enhanced humoral immunity, and non-live OLB6378, which is more useful as a food ingredient, showed a more marked effect than the viable bacteria.

  3. Structural evolution of small ruthenium cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Waldt, Eugen [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Hehn, Anna-Sophia; Ahlrichs, Reinhart [Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany); Kappes, Manfred M.; Schooss, Detlef, E-mail: detlef.schooss@kit.edu [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany)

    2015-01-14

    The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru{sub 8}{sup −}–Ru{sub 12}{sup −} have simple cubic structures, Ru{sub 13}{sup −}–Ru{sub 16}{sup −} form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru{sub 17}{sup −}, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru{sub 18}{sup −}–Ru{sub 20}{sup −}. Our calculations also predict simple cubic structures for the smaller clusters Ru{sub 4}{sup −}–Ru{sub 7}{sup −}, which were not accessible to electron diffraction measurements.

  4. On Clustering Criteria for Smooth Distributions

    CERN Document Server

    Bharath, Karthik; Dey, Dipak K

    2012-01-01

    We develop a clustering framework, motivated by the problem of testing for jumps in continuous-time stochastic process models, and derive its asymptotic properties under a general setup. Our technique is applicable whenever we have data from a population with a smooth distribution function. We then propose an intuitive and easily verifiable clustering criterion, based on the Empirical Cross-over Function, which provides us with the requisite tools to develop a test for the presence of jumps. We illustrate the validity of our theory on the popular Merton and Kou models for asset pricing with the objective of investigating jumps occurring in these models as a phenomena which leads to the formation of clusters.

  5. Determination of atomic cluster structure with cluster fusion algorithm

    DEFF Research Database (Denmark)

    Obolensky, Oleg I.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2005-01-01

    We report an efficient scheme of global optimization, called cluster fusion algorithm, which has proved its reliability and high efficiency in determination of the structure of various atomic clusters.......We report an efficient scheme of global optimization, called cluster fusion algorithm, which has proved its reliability and high efficiency in determination of the structure of various atomic clusters....

  6. The affective discourse dynamics of metaphor clustering The affective discourse dynamics of metaphor clustering

    Directory of Open Access Journals (Sweden)

    Lynne Cameron

    2010-05-01

    Full Text Available

    Metaphor is examined in the very different iscourse contexts of the classroom and of reconciliation talk to highlight the neglected affective dimension. The distribution of metaphors across discourse shows clustering at certain points, often where speakers are engaged in critical interpersonal discourse activity. Clusters in classroom talk co-occur with sequences of agenda management where teachers prepare students for upcoming lessons and with giving feedback to students, both of which require careful management of interpersonal and affective issues. Clusters in reconciliation talk co-occur with discourse management and with two situations with significant affective dynamics: appropriation of metaphor and exploration of alternative scenarios.

    Metaphor is examined in the very different iscourse contexts of the classroom and of reconciliation talk to highlight the neglected affective dimension. The distribution of metaphors across discourse shows clustering at certain points, often where speakers are engaged in critical interpersonal discourse activity. Clusters in classroom talk co-occur with sequences of agenda management where teachers prepare students for upcoming lessons and with giving feedback to students, both of which require careful management of interpersonal and affective issues. Clusters in reconciliation talk co-occur with discourse management and with two situations with significant affective dynamics: appropriation of metaphor and exploration of alternative scenarios.

  7. Cluster fusion algorithm: application to Lennard-Jones clusters

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2008-01-01

    paths up to the cluster size of 150 atoms. We demonstrate that in this way all known global minima structures of the Lennard-Jones clusters can be found. Our method provides an efficient tool for the calculation and analysis of atomic cluster structure. With its use we justify the magic number sequence...... for the clusters of noble gas atoms and compare it with experimental observations. We report the striking correspondence of the peaks in the dependence of the second derivative of the binding energy per atom on cluster size calculated for the chain of the Lennard-Jones clusters based on the icosahedral symmetry......We present a new general theoretical framework for modelling the cluster structure and apply it to description of the Lennard-Jones clusters. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system and absorbing its energy at each step, we find cluster growing...

  8. Cluster fusion algorithm: application to Lennard-Jones clusters

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2006-01-01

    paths up to the cluster size of 150 atoms. We demonstrate that in this way all known global minima structures of the Lennard-Jones clusters can be found. Our method provides an efficient tool for the calculation and analysis of atomic cluster structure. With its use we justify the magic number sequence...... for the clusters of noble gas atoms and compare it with experimental observations. We report the striking correspondence of the peaks in the dependence of the second derivative of the binding energy per atom on cluster size calculated for the chain of the Lennard-Jones clusters based on the icosahedral symmetry......We present a new general theoretical framework for modelling the cluster structure and apply it to description of the Lennard-Jones clusters. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system and absorbing its energy at each step, we find cluster growing...

  9. Cluster Based Text Classification Model

    DEFF Research Database (Denmark)

    2011-01-01

    We propose a cluster based classification model for suspicious email detection and other text classification tasks. The text classification tasks comprise many training examples that require a complex classification model. Using clusters for classification makes the model simpler and increases th...... datasets. Our model also outperforms A Decision Cluster Classification (ADCC) and the Decision Cluster Forest Classification (DCFC) models on the Reuters-21578 dataset....

  10. FINDCLUS : Fuzzy INdividual Differences CLUStering

    NARCIS (Netherlands)

    Giordani, Paolo; Kiers, Henk A. L.

    ADditive CLUStering (ADCLUS) is a tool for overlapping clustering of two-way proximity matrices (objects x objects). In Simple Additive Fuzzy Clustering (SAFC), a variant of ADCLUS is introduced providing a fuzzy partition of the objects, that is the objects belong to the clusters with the so-called

  11. Subspace K-means clustering

    NARCIS (Netherlands)

    Timmerman, Marieke E.; Ceulemans, Eva; De Roover, Kim; Van Leeuwen, Karla

    2013-01-01

    To achieve an insightful clustering of multivariate data, we propose subspace K-means. Its central idea is to model the centroids and cluster residuals in reduced spaces, which allows for dealing with a wide range of cluster types and yields rich interpretations of the clusters. We review the existi

  12. The Clustering of Intergalactic Metals

    CERN Document Server

    Pichon, C; Aracil, B; Petitjean, P; Aubert, D; Bergeron, J; Colombi, S; Pichon, Christophe; Scannapieco, Evan; Aracil, Bastien; Petitjean, Patrick; Aubert, Dominique; Bergeron, Jacqueline; Colombi, Stephane

    2003-01-01

    We measure the spatial clustering of metals in the intergalactic medium from z = 1.7 to 3.0, as traced by 643 CIV and 104 SiIV N >= 10^12 cm^-2 absorption systems in 19 high signal-to-noise (40-80) and high resolution (R = 45000) quasar spectra. The number densities and two-point correlation functions of both these species are largely constant with redshift, suggesting the bulk of metal ejection occurred at z >= 3. However, at z = M_s, and use numerical simulations to derive best-fit values of R_s ~ 2 comoving Mpc and M_s ~ 5x10^11 solar masses at z = 3. This does not exclude that metals could have been produced at higher redshifts in smaller, but equally rare, objects. At the level of detection of this survey, IGM enrichment is likely to be incomplete and inhomogeneous, with a filling factor ~ 10%.

  13. Lithopanspermia in star-forming clusters.

    Science.gov (United States)

    Adams, Fred C; Spergel, David N

    2005-08-01

    This paper considers the lithopanspermia hypothesis in star-forming groups and clusters, where the chances of biological material spreading from one solar system to another is greatly enhanced (relative to action in the field) because of the close proximity of the systems and lower relative velocities. These effects more than compensate for the reduced time spent in such crowded environments. This paper uses approximately 300,000 Monte Carlo scattering calculations to determine the cross sections for rocks to be captured by binaries and provides fitting formulae for other applications. We assess the odds of transfer as a function of the ejection speed v (eject) and number N(.) of members in the birth aggregate. The odds of any given ejected meteoroid being recaptured by another solar system are relatively low, about 1:10(3)-10(6) over the expected range of ejection speeds and cluster sizes. Because the number of ejected rocks (with mass m > 10 kg) per system can be large, N (R) approximately 10(16), virtually all solar systems are likely to share rocky ejecta with all of the other solar systems in their birth cluster. The number of ejected rocks that carry living microorganisms is much smaller and less certain, but we estimate that N (B) approximately 10(7) rocks can be ejected from a biologically active solar system. For typical birth environments, the capture of life-bearing rocks is expected to occur N (bio) asymptotically equal to 10-16,000 times (per cluster), depending on the ejection speeds. Only a small fraction (f (imp) approximately 10(4)) of the captured rocks impact the surfaces of terrestrial planets, so that N (lps) asymptotically equal to 10(3)-1.6 lithopanspermia events are expected per cluster (under favorable conditions). Finally, we discuss the question of internal versus external seeding of clusters and the possibility of Earth seeding young clusters over its biologically active lifetime.

  14. Cluster Implantation and Deposition Apparatus

    DEFF Research Database (Denmark)

    Hanif, Muhammad; Popok, Vladimir

    2015-01-01

    In the current report, a design and capabilities of a cluster implantation and deposition apparatus (CIDA) involving two different cluster sources are described. The clusters produced from gas precursors (Ar, N etc.) by PuCluS-2 can be used to study cluster ion implantation in order to develop...... contributions to the theory of cluster stopping in matter as well as for practical applications requiring ultra-shallow implantation and modification of surfaces on the nanoscale. Metal clusters from the magnetron cluster source are of interest for the production of optical sensors to detect specific biological...

  15. Stellar populations in star clusters

    CERN Document Server

    Li, Chengyuan; Deng, Licai

    2016-01-01

    Stellar populations contain the most important information about star clus- ter formation and evolution. Until several decades ago, star clusters were believed to be ideal laboratories for studies of simple stellar populations (SSPs). However, discoveries of multiple stellar populations in Galactic globular clusters have expanded our view on stellar populations in star clusters. They have simultaneously generated a number of controversies, particularly as to whether young star clusters may have the same origin as old globular clusters. In addition, extensive studies have revealed that the SSP scenario does not seem to hold for some intermediate-age and young star clusters either, thus making the origin of multiple stellar populations in star clusters even more complicated. Stellar population anomalies in numerous star clusters are well-documented, implying that the notion of star clusters as true SSPs faces serious challenges. In this review, we focus on stellar populations in massive clusters with different ...

  16. STRING: a web-server to retrieve and display the repeatedly occurring neighbourhood of a gene.

    Science.gov (United States)

    Snel, B; Lehmann, G; Bork, P; Huynen, M A

    2000-09-15

    The repeated occurrence of genes in each other's neighbourhood on genomes has been shown to indicate a functional association between the proteins they encode. Here we introduce STRING (search tool for recurring instances of neighbouring genes), a tool to retrieve and display the genes a query gene repeatedly occurs with in clusters on the genome. The tool performs iterative searches and visualises the results in their genomic context. By finding the genomically associated genes for a query, it delineates a set of potentially functionally associated genes. The usefulness of STRING is illustrated with an example that suggests a functional context for an RNA methylase with unknown specificity.

  17. Clustering by Pattern Similarity

    Institute of Scientific and Technical Information of China (English)

    Hai-xun Wang; Jian Pei

    2008-01-01

    The task of clustering is to identify classes of similar objects among a set of objects. The definition of similarity varies from one clustering model to another. However, in most of these models the concept of similarity is often based on such metrics as Manhattan distance, Euclidean distance or other Lp distances. In other words, similar objects must have close values in at least a set of dimensions. In this paper, we explore a more general type of similarity. Under the pCluster model we proposed, two objects are similar if they exhibit a coherent pattern on a subset of dimensions. The new similarity concept models a wide range of applications. For instance, in DNA microarray analysis, the expression levels of two genes may rise and fall synchronously in response to a set of environmental stimuli. Although the magnitude of their expression levels may not be close, the patterns they exhibit can be very much alike. Discovery of such clusters of genes is essential in revealing significant connections in gene regulatory networks. E-commerce applications, such as collaborative filtering, can also benefit from the new model, because it is able to capture not only the closeness of values of certain leading indicators but also the closeness of (purchasing, browsing, etc.) patterns exhibited by the customers. In addition to the novel similarity model, this paper also introduces an effective and efficient algorithm to detect such clusters, and we perform tests on several real and synthetic data sets to show its performance.

  18. Patterns of turnover and floristic similarity show a non-random distribution of naturalized flora in Chile, South America Patrones de recambio y similitud florística muestran una distribución no aleatoria de la flora naturalizada en Chile, Sudamérica

    Directory of Open Access Journals (Sweden)

    SERGIO A CASTRO

    2008-03-01

    Full Text Available The current geographical distribution of alien species could be informative of processes involved in the biological invasions facilitated by humans. Because environmental and anthropic factors affect the geographic distribution of alien plants, we hypothesize that naturalized plants have a non-random distribution along extensive geographical ranges. On the basis of a complete and updated database of naturalized plants in Chile, we analyzed their turnover and floristic similarities among regions that encompass a wide latitudinal gradient in South America. Using Moran's index and Mantel's test we characterized the spatial auto-correlation (regional aggregation and the effect of geographical distance on the index values. Additionally, we used clustering methods and resampling procedures to detect plant assemblages at regional level. Whittaker's index displayed a positive tilt, increasing according to geographical distance and reaching a plateau; conversely, Jaccard's index was negatively associated with geographical distance. Removing the effect of distance, both Whittaker's and Jaccard's values showed no significant trends. Multivariate analysis combined with resampling procedures revealed the existence of three distinctive plant clusters: Northernmost Chile, Central-southern Chile, and Southernmost Chile. These clusters are characterized by naturalized plants that are not present in the others. Based on this evidence, we conclude that the set of naturalized plants in Chile exhibits a non-random geographical distribution, displaying an ordered geographical pattern across regions (latitude. We discuss the role of the environmental variables (climate, latitude and land use post-European colonization as factors in the distributional patterns here documentedLa distribución geográfica actual de especies exóticas puede ser informativa de los procesos involucrados en las invasiones biológicas facilitadas por humanos. Debido a que los factores

  19. Maximum-likelihood cluster recontruction

    CERN Document Server

    Bartelmann, M; Seitz, S; Schneider, P J; Bartelmann, Matthias; Narayan, Ramesh; Seitz, Stella; Schneider, Peter

    1996-01-01

    We present a novel method to recontruct the mass distribution of galaxy clusters from their gravitational lens effect on background galaxies. The method is based on a least-chisquare fit of the two-dimensional gravitational cluster potential. The method combines information from shear and magnification by the cluster lens and is designed to easily incorporate possible additional information. We describe the technique and demonstrate its feasibility with simulated data. Both the cluster morphology and the total cluster mass are well reproduced.

  20. Robust multi-scale clustering of large DNA microarray datasets with the consensus algorithm

    DEFF Research Database (Denmark)

    Grotkjær, Thomas; Winther, Ole; Regenberg, Birgitte

    2006-01-01

    Motivation: Hierarchical and relocation clustering (e.g. K-means and self-organizing maps) have been successful tools in the display and analysis of whole genome DNA microarray expression data. However, the results of hierarchical clustering are sensitive to outliers, and most relocation methods...... analysis by collecting re-occurring clustering patterns in a co-occurrence matrix. The results show that consensus clustering obtained from clustering multiple times with Variational Bayes Mixtures of Gaussians or K-means significantly reduces the classification error rate for a simulated dataset....... The method is flexible and it is possible to find consensus clusters from different clustering algorithms. Thus, the algorithm can be used as a framework to test in a quantitative manner the homogeneity of different clustering algorithms. We compare the method with a number of state-of-the-art clustering...

  1. Clustered survival data with left-truncation

    DEFF Research Database (Denmark)

    Eriksson, Frank; Martinussen, Torben; Scheike, Thomas H.

    2015-01-01

    Left-truncation occurs frequently in survival studies, and it is well known how to deal with this for univariate survival times. However, there are few results on how to estimate dependence parameters and regression effects in semiparametric models for clustered survival data with delayed entry...... are investigated via simulation studies, and the suggested estimators are used in a study of prostate cancer based on the Finnish twin cohort where a twin pair is included only if both twins were alive in 1974....

  2. Clustering Game Behavior Data

    DEFF Research Database (Denmark)

    Bauckhage, C.; Drachen, Anders; Sifa, Rafet

    2015-01-01

    Recent years have seen a deluge of behavioral data from players hitting the game industry. Reasons for this data surge are many and include the introduction of new business models, technical innovations, the popularity of online games, and the increasing persistence of games. Irrespective...... of the causes, the proliferation of behavioral data poses the problem of how to derive insights therefrom. Behavioral data sets can be large, time-dependent and high-dimensional. Clustering offers a way to explore such data and to discover patterns that can reduce the overall complexity of the data. Clustering...... and other techniques for player profiling and play style analysis have, therefore, become popular in the nascent field of game analytics. However, the proper use of clustering techniques requires expertise and an understanding of games is essential to evaluate results. With this paper, we address game data...

  3. Exotic cluster structures on

    CERN Document Server

    Gekhtman, M; Vainshtein, A

    2017-01-01

    This is the second paper in the series of papers dedicated to the study of natural cluster structures in the rings of regular functions on simple complex Lie groups and Poisson-Lie structures compatible with these cluster structures. According to our main conjecture, each class in the Belavin-Drinfeld classification of Poisson-Lie structures on \\mathcal{G} corresponds to a cluster structure in \\mathcal{O}(\\mathcal{G}). The authors have shown before that this conjecture holds for any \\mathcal{G} in the case of the standard Poisson-Lie structure and for all Belavin-Drinfeld classes in SL_n, n<5. In this paper the authors establish it for the Cremmer-Gervais Poisson-Lie structure on SL_n, which is the least similar to the standard one.

  4. The properties, origin and evolution of stellar clusters in galaxy simulations and observations

    Science.gov (United States)

    Dobbs, C. L.; Adamo, A.; Few, C. G.; Calzetti, D.; Dale, D. A.; Elmegreen, B. G.; Evans, A. S.; Gouliermis, D. A.; Grasha, K.; Grebel, E. K.; Kim, H.; Johnson, K. E.; Lee, J. C.; Messa, M.; Ryon, J. E.; Smith, L. J.; Ubeda, L.; Whitmore, B.

    2016-09-01

    We investigate the properties and evolution of star particles in two simulations of isolated spiral galaxies, and two galaxies from cosmological simulations. Unlike previous numerical work, where typically each star particle represents one `cluster', for the isolated galaxies we are able to model features we term `clusters' with groups of particles. We compute the spatial distribution of stars with different ages, and cluster mass distributions, comparing our findings with observations including the recent LEGUS survey. We find that spiral structure tends to be present in older (100s Myrs) stars and clusters in the simulations compared to the observations. This likely reflects differences in the numbers of stars or clusters, the strength of spiral arms, and whether the clusters are allowed to evolve. Where we model clusters with multiple particles, we are able to study their evolution. The evolution of simulated clusters tends to follow that of their natal gas clouds. Massive, dense, long-lived clouds host massive clusters, whilst short-lived clouds host smaller clusters which readily disperse. Most clusters appear to disperse fairly quickly, in basic agreement with observational findings. We note that embedded clusters may be less inclined to disperse in simulations in a galactic environment with continuous accretion of gas onto the clouds than isolated clouds and correspondingly, massive young clusters which are no longer associated with gas tend not to occur in the simulations. Caveats of our models include that the cluster densities are lower than realistic clusters, and the simplistic implementation of stellar feedback.

  5. Evaluation of the Prevention and Reactivation Care Program (PReCaP for the hospitalized elderly: a prospective nonrandomized controlled trial

    Directory of Open Access Journals (Sweden)

    Asmus-Szepesi KJ

    2015-03-01

    Full Text Available Kirsten J Asmus-Szepesi,1 Linda E Flinterman,1 Marc A Koopmanschap,2 Anna P Nieboer,2 Ton J Bakker,3 Johan P Mackenbach,1 Ewout W Steyerberg1 1Department of Public Health, Erasmus University Medical Center, 2Institute of Health Policy and Management, Erasmus University, 3Stichting Wetenschap Balans, Rotterdam, the Netherlands Background: The hospitalized elderly are at risk of functional decline. We evaluated the effects and care costs of a specialized geriatric rehabilitation program aimed at preventing functional decline among at-risk hospitalized elderly.Methods: The prospective nonrandomized controlled trial reported here was performed in three hospitals in the Netherlands. One hospital implemented the Prevention and Reactivation Care Program (PReCaP, while two other hospitals providing usual care served as control settings. Within the PReCaP hospital we compared patients pre-implementation with patients post-implementation of the PReCaP (“within-hospital analysis”, while our nonrandomized controlled trial compared patients of the PReCaP hospital post-implementation with patients from the two control hospitals providing usual care (“between-hospital analysis”. Hospitalized patients 65 years or older and at risk of functional decline were interviewed at baseline and at 3 and 12 months using validated questionnaires to score functioning, depression, and health-related quality of life (HRQoL. We estimated costs per unit of care from hospital information systems and national data sources. We used adjusted general linear mixed models to analyze functioning and HRQoL.Results: Between-hospital analysis showed no difference in activities of daily living (ADL or instrumental activities of daily living (IADL between PReCaP patients and control groups. PReCaP patients did have slightly better cognitive functioning (Mini Mental State Examination; 0.4 [95% confidence interval (CI 0.2–0.6], lower depression (Geriatric Depression Scale 15; -0

  6. Kinematics of Clustering

    CERN Document Server

    Wang, Steven; Metcalfe, Guy; Wu, Jie

    2014-01-01

    The dynamical system for inertial particles in fluid flow has both attracting and repelling regions, the interplay of which can localize particles. In laminar flow experiments we find that particles, initially moving throughout the fluid domain, can undergo an instability and cluster into subdomains of the fluid when the flow Reynolds number exceeds a critical value that depends on particle and fluid inertia. We derive an expression for the instability boundary and for a universal curve that describes the clustering rate for all particles.

  7. Clustering via Kernel Decomposition

    DEFF Research Database (Denmark)

    Have, Anna Szynkowiak; Girolami, Mark A.; Larsen, Jan

    2006-01-01

    Methods for spectral clustering have been proposed recently which rely on the eigenvalue decomposition of an affinity matrix. In this work it is proposed that the affinity matrix is created based on the elements of a non-parametric density estimator. This matrix is then decomposed to obtain...... posterior probabilities of class membership using an appropriate form of nonnegative matrix factorization. The troublesome selection of hyperparameters such as kernel width and number of clusters can be obtained using standard cross-validation methods as is demonstrated on a number of diverse data sets....

  8. South Asian Cluster

    Directory of Open Access Journals (Sweden)

    Ionel Sergiu Pirju

    2014-12-01

    Full Text Available This article aims at presenting the South Asian cluster composed of India, Indonesia, Iran and Malaysia, the intercultural values that characterizes it, the supported leadership style and tracing the main macroeconomic considerations which characterizes them. The research is synchronic, analysing the contemporary situation of these countries without reference to their evolution in time, by using the positivist paradigm that explains the reality at one point. It will be analysed the overall cluster with the existing interactions between the countries that composes it, while the article being one of information will avoid building recommendation, or new theories.

  9. Cluster-tilting theory

    OpenAIRE

    Simões, Raquel Coelho Guardado

    2008-01-01

    Tese de mestado em Matemática (Álgebra, Lógica e Fundamentos) apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2008 Resumo alargado disponível em português The notion of Cluster Algebra first appeared in 2001, in a paper by S. Fomin and A. Zelevinsky, studying the dual canonical basis of the quantum group of a finite dimensional simple Lie algebra over the complex numbers, and also total positivity for algebraic groups. Cluster categories, introduced by A. Buan, R...

  10. I Cluster geografici

    Directory of Open Access Journals (Sweden)

    Maurizio Rosina

    2010-03-01

    Full Text Available Geographic ClustersOver the past decade, public alphanumeric database have been growing at exceptional rate. Most of data can be georeferenced, so that is possible gaining new knowledge from such databases. The contribution of this paper is two-fold. We first present a model of geographic clusters, which uses only geographic and functionally data properties. The model is useful to process huge amount of public/government data, even daily upgrading. After that, we merge the model into the framework GEOPOI (GEOcoding Points Of Interest, and show some graphic map results.

  11. Clustering high dimensional data

    DEFF Research Database (Denmark)

    Assent, Ira

    2012-01-01

    High-dimensional data, i.e., data described by a large number of attributes, pose specific challenges to clustering. The so-called ‘curse of dimensionality’, coined originally to describe the general increase in complexity of various computational problems as dimensionality increases, is known...... to render traditional clustering algorithms ineffective. The curse of dimensionality, among other effects, means that with increasing number of dimensions, a loss of meaningful differentiation between similar and dissimilar objects is observed. As high-dimensional objects appear almost alike, new approaches...

  12. Effective Group Training for Patients with Unexplained Physical Symptoms: A Randomized Controlled Trial with a Non-Randomized One-Year Follow-Up

    Science.gov (United States)

    Zonneveld, Lyonne N. L.; van Rood, Yanda R.; Timman, Reinier; Kooiman, Cornelis G.; van't Spijker, Adriaan; Busschbach, Jan J. V.

    2012-01-01

    Background Although cognitive-behavioral therapy for Unexplained Physical Symptoms (UPS) is effective in secondary care, studies done in primary care produced implementation problems and conflicting results. We evaluated the effectiveness of a cognitive-behavioral group training tailored to primary care patients and provided by a secondary community mental-health service reaching out into primary care. Methodology/Principal Findings The effectiveness of this training was explored in a randomized controlled trial. In this trial, 162 patients with UPS classified as undifferentiated somatoform disorder or as chronic pain disorder were randomized either to the training or a waiting list. Both lasted 13 weeks. The preservation of the training's effect was analyzed in non-randomized follow-ups, for which the waiting group started the training after the waiting period. All patients attended the training were followed-up after three months and again after one year. The primary outcomes were the physical and the mental summary scales of the SF-36. Secondary outcomes were the other SF-36-scales and the SCL-90-R. The courses of the training's effects in the randomized controlled trial and the follow-ups were analyzed with linear mixed modeling. In the randomized controlled trial, the training had a significantly positive effect on the quality of life in the physical domain (Cohen's d = 0.38;p = .002), but this overall effect was not found in the mental domain. Regarding the secondary outcomes, the training resulted in reporting an improved physical (Cohen's d = 0.43;p = 0.01), emotional (Cohen's d = 0.44;p = .0.01), and social (Cohen's d = 0.36;p = 0.01) functioning, less pain and better functioning despite pain (Cohen's d = 0.51;p =  PMID:22880056

  13. Effective group training for patients with unexplained physical symptoms: a randomized controlled trial with a non-randomized one-year follow-up.

    Directory of Open Access Journals (Sweden)

    Lyonne N L Zonneveld

    Full Text Available BACKGROUND: Although cognitive-behavioral therapy for Unexplained Physical Symptoms (UPS is effective in secondary care, studies done in primary care produced implementation problems and conflicting results. We evaluated the effectiveness of a cognitive-behavioral group training tailored to primary care patients and provided by a secondary community mental-health service reaching out into primary care. METHODOLOGY/PRINCIPAL FINDINGS: The effectiveness of this training was explored in a randomized controlled trial. In this trial, 162 patients with UPS classified as undifferentiated somatoform disorder or as chronic pain disorder were randomized either to the training or a waiting list. Both lasted 13 weeks. The preservation of the training's effect was analyzed in non-randomized follow-ups, for which the waiting group started the training after the waiting period. All patients attended the training were followed-up after three months and again after one year. The primary outcomes were the physical and the mental summary scales of the SF-36. Secondary outcomes were the other SF-36-scales and the SCL-90-R. The courses of the training's effects in the randomized controlled trial and the follow-ups were analyzed with linear mixed modeling. In the randomized controlled trial, the training had a significantly positive effect on the quality of life in the physical domain (Cohen's d = 0.38;p = .002, but this overall effect was not found in the mental domain. Regarding the secondary outcomes, the training resulted in reporting an improved physical (Cohen's d = 0.43;p = 0.01, emotional (Cohen's d = 0.44;p = 0.01, and social (Cohen's d = 0.36;p = 0.01 functioning, less pain and better functioning despite pain (Cohen's d = 0.51;p =

  14. Efficacy of Health Education using Facebook to Promote Healthy Lifestyle among Medical Students in Puducherry, India: A Non-Randomized Controlled Trial.

    Science.gov (United States)

    Krishnamohan, Smrithi; Stalin, P; Singh, Zile; Sridhar, Maghida

    2017-07-01

    Increasing burden of overweight and obesity among young adults is mainly due to unhealthy lifestyle especially with respect to diet and physical activity. At the same time, younger generations are spending more time with social network sites. Therefore, this study was intended to explore the role of social networking sites in promoting healthy lifestyle. To measure the efficacy of health education using social networking sites in promoting healthy lifestyle among medical students in Puducherry, India. A non-randomized controlled trial was conducted in a private medical college located in Puducherry. The study participants were overweight/obese individuals with (intervention arm) and without Facebook account (control arm). Following a baseline survey, both the groups received health education from dietician and physical trainer using Audiovisual (AV) aids. Intervention group received health education through Facebook in the forms of messages, pictures and videos for six weeks. Then, follow up survey was done to assess the change in dietary pattern, physical activity and body weight. Data of those who attended baseline, intervention and follow up surveys (23- control and 22- intervention) were analysed. Means and proportions were calculated. Paired t-test and Chi-square test were used to calculate the p-value. The p-valuejunk food intake per week was reduced in both control and intervention groups from 2.91 days/week and 3.27 days/week at baseline to 2.65 days/week to two days/week at follow up respectively. A significant decrease in the Body Mass Index (BMI) (pactivity and intake of fruits and vegetables. Except for the decrease in junk food intake, use of Facebook as an effective tool to promote healthy lifestyle could not be proved with confidence.

  15. Effect of cognitive behavioral group therapy for recovery of self-esteem on community-living individuals with mental illness: Non-randomized controlled trial.

    Science.gov (United States)

    Kunikata, Hiroko; Yoshinaga, Naoki; Nakajima, Kazuo

    2016-10-01

    The aim of this study was to examine over a 12-month post-intervention period whether the participation of community-living individuals with mental illness in cognitive behavioral group therapy for recovery of self-esteem (CBGTRS) resulted in improved outcomes. This was a non-randomized controlled trial. The participants were persons with mental illness who resided in communities in the Chugoku region of Japan. In total, 41 were assigned to an experimental group (CBGTRS intervention, 12 group sessions), and 21 to a control group. Outcome indices (self-esteem, moods, cognition, subjective well-being, psychiatric symptoms) were measured for the experimental group prior to intervention (T0), immediately post-intervention (T1), and at 3 (T2) and 12 (T3) months post-intervention. The control group was measured at the same intervals. For the experimental group, self-esteem scores at T1, T2, and T3 were significantly higher than at T0. Moods and cognition scores remained significantly low until T2. Scores for Inadequate Mental Mastery in the subjective well-being index had not decreased by T3. Confidence in Coping remained significantly high until T2. Psychiatric symptoms scores at T0, T1, T2, and T3 were significantly lower than at T0. The means and standard errors for self-esteem and Inadequate Mental Mastery increased until T3, and those for Tension-Anxiety, Depression-Dejection, and Confusion decreased until T2. From within-group trends and between-group differences in self-esteem, we conclude that CBGTRS may have a relatively long-term effect on self-esteem recovery. T2 is the turning point for moods and cognition; thus, follow-up is needed 3 months following the initial program. © 2016 The Authors. Psychiatry and Clinical Neurosciences © 2016 Japanese Society of Psychiatry and Neurology.

  16. Non-random temporary emigration and the robust design: Conditions for bias at the end of a time series: Section VIII

    Science.gov (United States)

    Langtimm, Catherine A.

    2008-01-01

    Deviations from model assumptions in the application of capture–recapture models to real life situations can introduce unknown bias. Understanding the type and magnitude of bias under these conditions is important to interpreting model results. In a robust design analysis of long-term photo-documented sighting histories of the endangered Florida manatee, I found high survival rates, high rates of non-random temporary emigration, significant time-dependence, and a diversity of factors affecting temporary emigration that made it difficult to model emigration in any meaningful fashion. Examination of the time-dependent survival estimates indicated a suspicious drop in survival rates near the end of the time series that persisted when the original capture histories were truncated and reanalyzed under a shorter time frame. Given the wide swings in manatee emigration estimates from year to year, a likely source of bias in survival was the convention to resolve confounding of the last survival probability in a time-dependent model with the last emigration probabilities by setting the last unmeasurable emigration probability equal to the previous year’s probability when the equality was actually false. Results of a series of simulations demonstrated that if the unmeasurable temporary emigration probabilities in the last time period were not accurately modeled, an estimation model with significant annual variation in survival probabilities and emigration probabilities produced bias in survival estimates at the end of the study or time series being explored. Furthermore, the bias propagated back in time beyond the last two time periods and the number of years affected varied positively with survival and emigration probabilities. Truncating the data to a shorter time frame and reanalyzing demonstrated that with additional years of data surviving temporary emigrants eventually return and are detected, thus in subsequent analysis unbiased estimates are eventually realized.

  17. Hepatic artery injection of {sup 131}I-labelled metuximab combined with chemoembolization for intermediate hepatocellular carcinoma: a prospective nonrandomized study

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lu; Yang, Ye-Fa; Ge, Nai-Jian; Shen, Shu-Qun; Liang, Jun [Second Military Medical University, The First Department of Interventional Radiology, Eastern Hepatobiliary Surgery Hospital, Shanghai (China); Wang, Yi [Second Military Medical University, The Second Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Shanghai (China); Zhou, Wei-Ping [Second Military Medical University, The Third Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Shanghai (China); Shen, Feng; Wu, Meng-Chao [Second Military Medical University, Eastern Hepatobiliary Surgery Hospital, Shanghai (China)

    2012-08-15

    Hepatocellular carcinoma (HCC) is the fifth and seventh most common cause of cancer in men and women, respectively. Transcatheter arterial chemoembolization (TACE) is the standardized therapy for the intermediate stage of HCC. However, the 3-year overall survival remains low (<30 %) in these patients. Thus, there is a critical need for the development of treatment modalities to improve the survival rate. This study aimed to evaluate whether the combination of {sup 131}I-metuximab with chemoembolization could improve treatment efficiency. Between January 2009 and January 2010, a prospective two-arm nonrandomized study was performed in patients with intermediate HCC. Of 138 patients, 68 (combination therapy group) received 132 courses of intraarterial {sup 131}I-metuximab injections combined with chemoembolization (mean 1.94 per patient, median 2, range 1-2), followed by 152 sessions of TACE (mean 2.24 per patient, median 2, range 0-4). The remaining 70 patients (monotherapy group) received 296 sessions of TACE (mean 4.23 per patient, median 4, range 1-7). The overall median survival times for the combination therapy group and the group treated only with TACE were 26.7 months (95 % CI 20.7-31.3 months) and 20.6 months (95 % CI 15.3-24.7 months), respectively. The combination therapy group had a significantly higher survival rate than the TACE-only group (P = 0.038). Age {>=}65 years, serum albumin {<=}35 g/l, and treatment category (combination therapy or TACE only) were independent prognostic factors for survival according to multivariate analysis. The combination of {sup 131}I-metuximab and chemoembolization extended survival in patients with intermediate HCC compared with TACE only, and was well tolerated by patients with Child-Pugh class A or B disease. This combination seems to be a promising treatment modality for patients with intermediate HCC. (orig.)

  18. Rock magnetic evidence of non-random raw material selection criteria in Cerro Toledo Obsidian Artifacts from Valles Caldera, New Mexico

    Science.gov (United States)

    Gregovich, A.; Feinberg, J. M.; Steffen, A.; Sternberg, R. S.

    2014-12-01

    Stone tools are one of the most enduring forms of ancient human behavior available to anthropologists. The geologic materials that comprise stone tools are a reflection of the rocks that were available locally or through trade, as are the intended use of the tools and the knapping technology needed to produce them. Investigation of the rock magnetic and geochemical characteristics of the artifacts and the geological source materials provides a baseline to explore these past behaviors. This study uses rock magnetic properties to explore the raw material selection criteria involved in the production of obsidian tools in the region around Valles Caldera in northern New Mexico. Obsidian is locally abundant and was traded by tribes across the central United States. Here we compare the rock magnetic properties of a sample of obsidian projectile points (N =25) that have been geochemically sourced to the Cerro Toledo obsidian flow with geological samples collected from four sites within the same flow (N =135). This collection of archaeological artifacts, albeit small, contains representatives of at least 8 different point styles that were used over 6000 years from the Archaic into the Late Prehistoric. Bulk rock hysteresis parameters (Mr, Ms, Bc, and Bcr) and low-field susceptibility (Χ) measurements show that the projectile points generally contain a lower concentration of magnetic minerals than the geologic samples. For example, the artifacts' median Ms value is 2.9 x 10-3 Am2kg-1, while that of the geological samples is 6.5 x 10-3 Am2kg-1. The concentration of magnetic minerals in obsidian is a proxy for the concentration of microlites in general, and this relationship suggests that although obsidian was locally abundant, toolmakers employed non-random selection criteria resulting in generally lower concentrations of microlites in their obsidian tools.

  19. Spiritual Care Therapy on Quality of Life in Cancer Patients and Their Caregivers: A Prospective Non-randomized Single-Cohort Study.

    Science.gov (United States)

    Sankhe, A; Dalal, K; Agarwal, V; Sarve, P

    2017-04-01

    Spiritual care is still in infancy stage all over the globe including India. The present study was an original study evaluating the role of spiritual care in cancer patients and their primary caregivers regarding their spiritual and general well-being. The study was a prospective, non-randomized single-group study involving cancer patients undergoing surgery and their primary caregivers. Functional assessment of cancer therapy-general and functional assessment of chronic illness therapy-spiritual care was evaluated during the admission and at the time of discharge, two, four  and 6 months following discharge from the hospital. Descriptive statistics was used for demographic details and repeated measure ANOVA with Dunn's test was used for analysis of changes in the scores. A total of 107 (63 males and 44 females) patients with a mean (SD) of age 51 (13) years were recruited in the study. Similarly, for each patient one of their primary caregivers was recruited with their mean (SD) age of 39.4 (12.7) years. A total of 11/107 (10.3%) patients died and nine out of 107 (8.4%) were lost to follow-up eventually during the study period. There was a statistically significant (P spiritual care on the basis of MATCH guideline improved the level of not only spiritual well-being but general well-being also in both the patients and their primary caregivers. Control group could have improved scientific validity of study in accessing effect of spiritual care. Authors believe that more robust comparative study on each principle against all five MATCH principles in future will add scientific validity and clear the various ambiguities in spiritual care.

  20. Brachytherapy versus radical hysterectomy after external beam chemoradiation: a non-randomized matched comparison in IB2-IIB cervical cancer patients

    Directory of Open Access Journals (Sweden)

    Flores Vladimir

    2009-02-01

    Full Text Available Abstract Background A current paradigm in the treatment of cervical cancer with radiation therapy is that intracavitary brachytherapy is an essential component of radical treatment. This is a matched retrospective comparison of the results of treatment in patients treated with external beam chemoradiation (EBRT-CT and radical hysterectomy versus those treated with identical chemoradiation followed by brachytherapy. Methods In this non-randomized comparison EBRT-CT protocol was the same in both groups of 40 patients. In the standard treated patients, EBRT-CT was followed by one or two intracavitary Cesium (low-dose rate applications within 2 weeks of finishing external radiation to reach a point A dose of at least 85 Gy. In the surgically treated patients, radical hysterectomy with bilateral pelvic lymph node dissection and para-aortic lymph node sampling were performed within 7 weeks after EBRT-CT. Response, toxicity and survival were evaluated. Results A total of 80 patients were analyzed. The patients receiving EBRT-CT and surgery were matched with the standard treated cases. There were no differences in the clinicopathological characteristics between groups or in the delivery of EBRT-CT. The pattern of acute and late toxicity differed. Standard treated patients had more chronic proctitis while the surgically treated had acute complications of surgery and hydronephrosis. At a maximum follow-up of 60 months, median follow-up 26 (2–31 and 22 (3–27 months for the surgery and standard therapy respectively, eight patients per group have recurred and died. The progression free and overall survival are the same in both groups. Conclusion The results of this study suggest that radical hysterectomy can be used after EBRT-CT without compromising survival in FIGO stage IB2-IIB cervical cancer patients in settings were brachytherapy is not available. A randomized study is needed to uncover the value of surgery after EBRT-CT.

  1. A prospective, non-randomized phase II trial of Trastuzumab and Capecitabine in patients with HER2 expressing metastasized pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Endlicher Esther

    2009-01-01

    Full Text Available Abstract Background Pancreatic cancer is the fourth most common cause of cancer related death in Western countries. Advantages in surgical techniques, radiation and chemotherapy had almost no impact on the long term survival of affected patients. Therefore, the need for better treatment strategies is urgent. HER2, a receptor tyrosine kinase of the EGFR family, involved in signal transduction pathways leading to cell growth and differentiation is overexpressed in a number of cancers, including breast and pancreatic cancer. While in breast cancer HER2 has already been successfully used as a treatment target, there are only limited data evaluating the effects of inhibiting HER2 tyrosine kinases in patients with pancreatic cancer. Methods Here we report the design of a prospective, non-randomized multi-centered Phase II clinical study evaluating the effects of the Fluoropyrimidine-carbamate Capecitabine (Xeloda ® and the monoclonal anti-HER2 antibody Trastuzumab (Herceptin® in patients with non-resectable, HER2 overexpressing pancreatic cancer. Patients eligible for the study will receive Trastuzumab infusions on day 1, 8 and 15 concomitant to the oral intake of Capecitabine from day 1 to day 14 of each three week cylce. Cycles will be repeated until tumor progression. A total of 37 patients will be enrolled with an interim analysis after 23 patients. Discussion Primary end point of the study is to determine the progression free survival after 12 weeks of bimodal treatment with the chemotherapeutic agent Capecitabine and the anti-HER2 antibody Trastuzumab. Secondary end points include patient's survival, toxicity analysis, quality of life, the correlation of HER2 overexpression and clinical response to Trastuzumab treatment and, finally, the correlation of CA19-9 plasma levels and progression free intervals.

  2. Size-dependent reactions of ammonium bisulfate clusters with dimethylamine.

    Science.gov (United States)

    Bzdek, Bryan R; Ridge, Douglas P; Johnston, Murray V

    2010-11-04

    The reaction kinetics of ammonium bisulfate clusters with dimethylamine (DMA) gas were investigated using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Clusters ranged in size from 1 to 10 bisulfate ions. Although displacement of the first several ammonium ions by DMA occurred with near unit efficiency, displacement of the final ammonium ion was cluster size dependent. For small clusters, all ammonium ions are exposed to incoming DMA molecules, allowing for facile exchange ("surface" exchange). However, with increasing cluster size, an ammonium ion can be trapped in an inaccessible region of the cluster ("core" exchange), thereby rendering exchange difficult. DMA was also observed to add onto existing dimethylaminium bisulfate clusters above a critical size, whereas ammonia did not add onto ammonium bisulfate clusters. The results suggest that as the cluster size increases, di-dimethylaminium sulfate formation becomes more favorable. The results of this study give further evidence to suggest that ambient sub-3 nm diameter particles are likely to contain aminium salts rather than ammonium salts.

  3. Supersonic Line Broadening within Young and Massive Super Star Clusters

    CERN Document Server

    Tenorio-Tagle, G; Silich, S; Munoz-Tunon, C; Palous, J

    2009-01-01

    The origin of supersonic infrared and radio recombination nebular lines often detected in young and massive superstar clusters are discussed. We suggest that these arise from a collection of repressurizing shocks (RSs), acting effectively to re-establish pressure balance within the cluster volume and from the cluster wind which leads to an even broader although much weaker component. The supersonic lines are here shown to occur in clusters that undergo a bimodal hydrodynamic solution (Tenorio-Tagle et al. 2007), that is within clusters that are above the threshold line in the mechanical luminosity or cluster mass vs the size of the cluster (Silich et al. 2004). The plethora of repressurizing shocks is due to frequent and recurrent thermal instabilities that take place within the matter reinserted by stellar winds and supernovae. We show that the maximum speed of the RSs and of the cluster wind, are both functions of the temperature reached at the stagnation radius. This temperature depends only on the cluster...

  4. An Emerge Approach in Inter Cluster Similarity for Quality Clusters

    Directory of Open Access Journals (Sweden)

    H. Venkateswara Reddy

    2013-04-01

    Full Text Available Relationship between the datasets is one most important issue in recent years. The recent methods are based mostly on the numerical data, but these methods are not suitable for real time data such as web pages, business transactions etc., which are known as Categorical data. It is difficult to find relationship in categorical data. In this paper, a new approach is proposed for finding the relationshipbetween the categorical data, hence to find relationship between the clusters. The main aim is to identify the quality clusters based on the relationship between clusters. If there is no relationship between clusters then those clusters are treated as quality clusters.

  5. Combining cluster number counts and galaxy clustering

    CERN Document Server

    Lacasa, Fabien

    2016-01-01

    We present a detailed modelling of the joint covariance matrix between cluster number counts and the galaxy angular power spectrum. To this end, we use a Halo Model framework complemented by a Halo Occupation Distribution model (HOD), and we work in full-sky. We demonstrate the importance of accounting for non-Gaussianity to produce accurate covariance predictions, as the Gaussian part of the covariance can in fact become subdominant in certain configurations. We discuss in particular the case of the super-sample covariance (SSC), including the effects of galaxy shot-noise, halo second order bias and non-local bias, and demonstrating interesting mathematical properties. Using the joint covariance matrix and a Fisher matrix methodology, we examine the prospects of combining these two probes to constrain cosmological and HOD parameters. We find that the combination indeed results in noticeable better constraints, in particular because the cross-covariance introduces a synergy between the probes on small scales....

  6. Localized attack on clustering networks

    CERN Document Server

    Dong, Gaogao; Du, Ruijin; Shao, Shuai; Stanley, H Eugene; Shlomo, Havlin

    2016-01-01

    Clustering network is one of which complex network attracting plenty of scholars to discuss and study the structures and cascading process. We primarily analyzed the effect of clustering coefficient to other various of the single clustering network under localized attack. These network models including double clustering network and star-like NON with clustering and random regular (RR) NON of ER networks with clustering are made up of at least two networks among which exist interdependent relation among whose degree of dependence is measured by coupling strength. We show both analytically and numerically, how the coupling strength and clustering coefficient effect the percolation threshold, size of giant component, critical coupling point where the behavior of phase transition changes from second order to first order with the increase of coupling strength between the networks. Last, we study the two types of clustering network: one type is same with double clustering network in which each subnetwork satisfies ...

  7. Clustering of resting state networks.

    Directory of Open Access Journals (Sweden)

    Megan H Lee

    Full Text Available BACKGROUND: The goal of the study was to demonstrate a hierarchical structure of resting state activity in the healthy brain using a data-driven clustering algorithm. METHODOLOGY/PRINCIPAL FINDINGS: The fuzzy-c-means clustering algorithm was applied to resting state fMRI data in cortical and subcortical gray matter from two groups acquired separately, one of 17 healthy individuals and the second of 21 healthy individuals. Different numbers of clusters and different starting conditions were used. A cluster dispersion measure determined the optimal numbers of clusters. An inner product metric provided a measure of similarity between different clusters. The two cluster result found the task-negative and task-positive systems. The cluster dispersion measure was minimized with seven and eleven clusters. Each of the clusters in the seven and eleven cluster result was associated with either the task-negative or task-positive system. Applying the algorithm to find seven clusters recovered previously described resting state networks, including the default mode network, frontoparietal control network, ventral and dorsal attention networks, somatomotor, visual, and language networks. The language and ventral attention networks had significant subcortical involvement. This parcellation was consistently found in a large majority of algorithm runs under different conditions and was robust to different methods of initialization. CONCLUSIONS/SIGNIFICANCE: The clustering of resting state activity using different optimal numbers of clusters identified resting state networks comparable to previously obtained results. This work reinforces the observation that resting state networks are hierarchically organized.

  8. A galactic-scale origin for stellar clustering

    CERN Document Server

    Kruijssen, J M Diederik

    2012-01-01

    We recently presented a model for the cluster formation efficiency (CFE), i.e. the fraction of star formation occurring in bound stellar clusters. It utilizes the idea that the formation of stars and stellar clusters occurs across a continuous spectrum of ISM densities. Bound stellar clusters naturally arise from the high-density end of this density spectrum. Due to short free-fall times, these high-density regions can achieve high star formation efficiencies (SFEs) and can be unaffected by gas expulsion. Lower-density regions remain gas-rich and substructured, and are unbound upon gas expulsion. The model enables the CFE to be calculated using galactic-scale observables. I present a brief summary of the model physics, assumptions and caveats, and show that it agrees well with observations. Fortran and IDL routines for calculating the CFE are publicly available at http://www.mpa-garching.mpg.de/cfe.

  9. Naturally Occuring Brands: a New Perspective on Place Marketing

    National Research Council Canada - National Science Library

    Christine Wright-Isak

    2010-01-01

      Naturally Occurring Brands: A New Perspective on Place Marketing We suggest community types are "natural brands," because their differentiated imagery has meaning that influences consumer housing choices...

  10. Detecting alternative graph clusterings.

    Science.gov (United States)

    Mandala, Supreet; Kumara, Soundar; Yao, Tao

    2012-07-01

    The problem of graph clustering or community detection has enjoyed a lot of attention in complex networks literature. A quality function, modularity, quantifies the strength of clustering and on maximization yields sensible partitions. However, in most real world networks, there are an exponentially large number of near-optimal partitions with some being very different from each other. Therefore, picking an optimal clustering among the alternatives does not provide complete information about network topology. To tackle this problem, we propose a graph perturbation scheme which can be used to identify an ensemble of near-optimal and diverse clusterings. We establish analytical properties of modularity function under the perturbation which ensures diversity. Our approach is algorithm independent and therefore can leverage any of the existing modularity maximizing algorithms. We numerically show that our methodology can systematically identify very different partitions on several existing data sets. The knowledge of diverse partitions sheds more light into the topological organization and helps gain a more complete understanding of the underlying complex network.

  11. Clustering under Perturbation Resilience

    CERN Document Server

    Balcan, Maria Florina

    2011-01-01

    Recently, Bilu and Linial \\cite{BL} formalized an implicit assumption often made when choosing a clustering objective: that the optimum clustering to the objective should be preserved under small multiplicative perturbations to distances between points. They showed that for max-cut clustering it is possible to circumvent NP-hardness and obtain polynomial-time algorithms for instances resilient to large (factor $O(\\sqrt{n})$) perturbations, and subsequently Awasthi et al. \\cite{ABS10} considered center-based objectives, giving algorithms for instances resilient to O(1) factor perturbations. In this paper, we greatly advance this line of work. For the $k$-median objective, we present an algorithm that can optimally cluster instances resilient to $(1 + \\sqrt{2})$-factor perturbations, solving an open problem of Awasthi et al.\\cite{ABS10}. We additionally give algorithms for a more relaxed assumption in which we allow the optimal solution to change in a small $\\epsilon$ fraction of the points after perturbation. ...

  12. Resolved SZE Cluster Count

    Institute of Scientific and Technical Information of China (English)

    Jia-Yu Tang; Zu-Hui Fan

    2003-01-01

    We study the counts of resolved SZE (Sunyaev-Zel'dovich effect) clus-ters expected from an interferometric survey in different cosmological models underdifferent conditions. The self-similar universal gas model and Press-Schechter massfunction are used. We take the observing frequency to be 90 GHz, and consider twodish diameters, 1.2 m and 2.5 m. We calculate the number density of the galaxyclusters dN/(dΩdz) at a high flux limit Slimv = 100mJy and at a relative lowSlimv = 10 mJy. The total numbers of SZE clusters N in two low-Ω0 models arecompared. The results show that the influence of the resolved effect depends notonly on D, but also on Slimv: at a given D, the effect is more significant for a highthan for a low Slim Also, the resolved effect for a flat universe is more impressivethan that for an open universe. For D = 1.2m and Slimv= 10mJy, the resolvedeffect is very weak. Considering the designed interferometers which will be used tosurvey SZE clusters, we find that the resolved effect is insignificant when estimatingthe expected yield of the SZE cluster surveys.

  13. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    . We prove that computation of this model is NP-hard. For RESCU, we propose an approximative solution that shows high accuracy with respect to our relevance model. Thorough experiments on synthetic and real world data show that RESCU successfully reduces the result to manageable sizes. It reliably...... achieves top clustering quality while competing approaches show greatly varying performance....

  14. Cluster headaches simulating parasomnias.

    Science.gov (United States)

    Isik, Ugur; D'Cruz, O 'Neill F

    2002-09-01

    Nocturnal episodes of agitated arousal in otherwise healthy young children are often related to nonrapid eye movement parasomnias (night terrors). However, in patients with acute onset or increased frequency of parasomnias, organic causes of discomfort must be excluded. We report four young children whose parasomnias were caused by nocturnal cluster headaches and who responded to indomethacin dramatically.

  15. Fuzzy clustering of mechanisms

    Indian Academy of Sciences (India)

    Amitabha Ghosh; Dilip Kumar Pratihar; M V V Amarnath; Guenter Dittrich; Jorg Mueller

    2012-10-01

    During the course of development of Mechanical Engineering, a large number of mechanisms (that is, linkages to perform various types of tasks) have been conceived and developed. Quite a few atlases and catalogues were prepared by the designers of machines and mechanical systems. However, often it is felt that a clustering technique for handling the list of large number of mechanisms can be very useful,if it is developed based on a scientific principle. In this paper, it has been shown that the concept of fuzzy sets can be conveniently used for this purpose, if an adequate number of properly chosen attributes (also called characteristics) are identified. Using two clustering techniques, the mechanisms have been classified in the present work and in future, it may be extended to develop an expert system, which can automate type synthesis phase of mechanical design. To the best of the authors’ knowledge, this type of clustering of mechanisms has not been attempted before. Thus, this is the first attempt to cluster the mechanisms based on some quantitative measures. It may help the engineers to carry out type synthesis of the mechanisms.

  16. Emergence of regional clusters

    DEFF Research Database (Denmark)

    Dahl, Michael S.; Østergaard, Christian Richter; Dalum, Bent

    2010-01-01

    The literature on regional clusters has increased considerably during the last decade. The emergence and growth patterns are usually explained by such factors as unique local culture, regional capabilities, tacit knowledge or the existence of location-specific externalities (knowledge spillovers,...

  17. Hybrid cluster identification

    Science.gov (United States)

    Martín-Herrero, J.

    2004-10-01

    I present a hybrid method for the labelling of clusters in two-dimensional lattices, which combines the recursive approach with iterative scanning to reduce the stack size required by the pure recursive technique, while keeping its benefits: single pass and straightforward cluster characterization and percolation detection parallel to the labelling. While the capacity to hold the entire lattice in memory is usually regarded as the major constraint for the applicability of the recursive technique, the required stack size is the real limiting factor. Resorting to recursion only for the transverse direction greatly reduces the recursion depth and therefore the required stack. It also enhances the overall performance of the recursive technique, as is shown by results on a set of uniform random binary lattices and on a set of samples of the Ising model. I also show how this technique may replace the recursive technique in Wolff's cluster algorithm, decreasing the risk of stack overflow and increasing its speed, and the Hoshen-Kopelman algorithm in the Swendsen-Wang cluster algorithm, allowing effortless characterization during generation of the samples and increasing its speed.

  18. Dettagli utilizzo cluster INTEL

    OpenAIRE

    2012-01-01

    Dall'inizio dell'anno 2004 il CILEA ospita e gestisce un cluster di processori Intel a 32 bit denominato avogadro. Esso é costituito da 128 nodi biprocessori Intel Xeon 3.06 GHz. L'articolo intende presentare le problematiche relative all'utilizzo della macchina processore fornendo le istruzioni operative necessarie all'uso più efficace.

  19. PVM Support for Clusters

    Science.gov (United States)

    Springer, P.

    2000-01-01

    The latest version of PVM (3.4.3) now contains support for a PC cluster running Linux, also known as a Beowulf system. A PVM user of a computer outside the Beowulf system can add the Beowulf as a single machine.

  20. Large Crater Clustering tool

    Science.gov (United States)

    Laura, Jason; Skinner, James A.; Hunter, Marc A.

    2017-08-01

    In this paper we present the Large Crater Clustering (LCC) tool set, an ArcGIS plugin that supports the quantitative approximation of a primary impact location from user-identified locations of possible secondary impact craters or the long-axes of clustered secondary craters. The identification of primary impact craters directly supports planetary geologic mapping and topical science studies where the chronostratigraphic age of some geologic units may be known, but more distant features have questionable geologic ages. Previous works (e.g., McEwen et al., 2005; Dundas and McEwen, 2007) have shown that the source of secondary impact craters can be estimated from secondary impact craters. This work adapts those methods into a statistically robust tool set. We describe the four individual tools within the LCC tool set to support: (1) processing individually digitized point observations (craters), (2) estimating the directional distribution of a clustered set of craters, back projecting the potential flight paths (crater clusters or linearly approximated catenae or lineaments), (3) intersecting projected paths, and (4) intersecting back-projected trajectories to approximate the local of potential source primary craters. We present two case studies using secondary impact features mapped in two regions of Mars. We demonstrate that the tool is able to quantitatively identify primary impacts and supports the improved qualitative interpretation of potential secondary crater flight trajectories.

  1. Clustering Techniques in Bioinformatics

    National Research Council Canada - National Science Library

    Muhammad Ali Masood; M. N. A. Khan

    2015-01-01

    ... according to well-defined rules. Data mining, having the tools of data classification and data clustering, is one of the most powerful techniques to deal with data in such a manner that it can help researchers identify the required information...

  2. Extended Fuzzy Clustering Algorithms

    NARCIS (Netherlands)

    U. Kaymak (Uzay); M. Setnes

    2000-01-01

    textabstractFuzzy clustering is a widely applied method for obtaining fuzzy models from data. It has been applied successfully in various fields including finance and marketing. Despite the successful applications, there are a number of issues that must be dealt with in practical applications of fuz

  3. Disentangling Porterian Clusters

    DEFF Research Database (Denmark)

    Jagtfelt, Tue

    intertwined and that Porter’s consciously paradigmatic textbook very likely gained worldwide influence due to two interrelated factors. The first factor is the deliberately holistic gestalt figure propounded in Nations, which prompted scientific communities to pursue cluster research; the second factor...

  4. MultiDendrograms: Variable-Group Agglomerative Hierarchical Clustering

    CERN Document Server

    Gomez, Sergio; Montiel, Justo; Torres, David

    2012-01-01

    MultiDendrograms is a Java-written application that computes agglomerative hierarchical clusterings of data. Starting from a distances (or weights) matrix, MultiDendrograms is able to calculate its dendrograms using the most common agglomerative hierarchical clustering methods. The application implements a variable-group algorithm that solves the non-uniqueness problem found in the standard pair-group algorithm. This problem arises when two or more minimum distances between different clusters are equal during the agglomerative process, because then different output clusterings are possible depending on the criterion used to break ties between distances. MultiDendrograms solves this problem implementing a variable-group algorithm that groups more than two clusters at the same time when ties occur.

  5. uvbybeta photometry of early type open cluster and field stars

    CERN Document Server

    Handler, G

    2011-01-01

    The beta Cephei stars and slowly pulsating B (SPB) stars are massive main sequence variables. The strength of their pulsational driving strongly depends on the opacity of iron-group elements. As many of those stars naturally occur in young open clusters, whose metallicities can be determined in several fundamental ways, it is logical to study the incidence of pulsation in several young open clusters. To provide the foundation for such an investigation, Str\\"omgren-Crawford uvbybeta photometry of open cluster target stars was carried out to determine effective temperatures, luminosities, and therefore cluster memberships. In the course of three observing runs, uvbybeta photometry for 168 target stars was acquired and transformed into the standard system by measurements of 117 standard stars. The list of target stars also included some known cluster and field beta Cephei stars, as well as beta Cephei and SPB candidates that are targets of the asteroseismic part of the Kepler satellite mission. The uvbybeta phot...

  6. Data clustering algorithms and applications

    CERN Document Server

    Aggarwal, Charu C

    2013-01-01

    Research on the problem of clustering tends to be fragmented across the pattern recognition, database, data mining, and machine learning communities. Addressing this problem in a unified way, Data Clustering: Algorithms and Applications provides complete coverage of the entire area of clustering, from basic methods to more refined and complex data clustering approaches. It pays special attention to recent issues in graphs, social networks, and other domains.The book focuses on three primary aspects of data clustering: Methods, describing key techniques commonly used for clustering, such as fea

  7. Quartile Clustering: A quartile based technique for Generating Meaningful Clusters

    CERN Document Server

    Goswami, Saptarsi

    2012-01-01

    Clustering is one of the main tasks in exploratory data analysis and descriptive statistics where the main objective is partitioning observations in groups. Clustering has a broad range of application in varied domains like climate, business, information retrieval, biology, psychology, to name a few. A variety of methods and algorithms have been developed for clustering tasks in the last few decades. We observe that most of these algorithms define a cluster in terms of value of the attributes, density, distance etc. However these definitions fail to attach a clear meaning/semantics to the generated clusters. We argue that clusters having understandable and distinct semantics defined in terms of quartiles/halves are more appealing to business analysts than the clusters defined by data boundaries or prototypes. On the samepremise, we propose our new algorithm named as quartile clustering technique. Through a series of experiments we establish efficacy of this algorithm. We demonstrate that the quartile clusteri...

  8. Connected component identification and cluster update on GPU

    OpenAIRE

    Weigel, Martin

    2011-01-01

    Cluster identification tasks occur in a multitude of contexts in physics and engineering such as, for instance, cluster algorithms for simulating spin models, percolation simulations, segmentation problems in image processing, or network analysis. While it has been shown that graphics processing units (GPUs) can result in speedups of two to three orders of magnitude as compared to serial codes on CPUs for the case of local and thus naturally parallelized problems such as single-spin flip upda...

  9. Tidally Induced Bars of Galaxies in Clusters

    Science.gov (United States)

    Łokas, Ewa L.; Ebrová, Ivana; del Pino, Andrés; Sybilska, Agnieszka; Athanassoula, E.; Semczuk, Marcin; Gajda, Grzegorz; Fouquet, Sylvain

    2016-08-01

    Using N-body simulations, we study the formation and evolution of tidally induced bars in disky galaxies in clusters. Our progenitor is a massive, late-type galaxy similar to the Milky Way, composed of an exponential disk and a Navarro-Frenk-White dark matter halo. We place the galaxy on four different orbits in a Virgo-like cluster and evolve it for 10 Gyr. As a reference case, we also evolve the same model in isolation. Tidally induced bars form on all orbits soon after the first pericenter passage and survive until the end of the evolution. They appear earlier, are stronger and longer, and have lower pattern speeds for tighter orbits. Only for the tightest orbit are the properties of the bar controlled by the orientation of the tidal torque from the cluster at pericenter. The mechanism behind the formation of the bars is the angular momentum transfer from the galaxy stellar component to its halo. All of the bars undergo extended periods of buckling instability that occur earlier and lead to more pronounced boxy/peanut shapes when the tidal forces are stronger. Using all simulation outputs of galaxies at different evolutionary stages, we construct a toy model of the galaxy population in the cluster and measure the average bar strength and bar fraction as a function of clustercentric radius. Both are found to be mildly decreasing functions of radius. We conclude that tidal forces can trigger bar formation in cluster cores, but not in the outskirts, and thus can cause larger concentrations of barred galaxies toward the cluster center.

  10. Cluster-lensing: A Python Package for Galaxy Clusters & Miscentering

    OpenAIRE

    Ford, Jes; VanderPlas, Jake

    2016-01-01

    We describe a new open source package for calculating properties of galaxy clusters, including NFW halo profiles with and without the effects of cluster miscentering. This pure-Python package, cluster-lensing, provides well-documented and easy-to-use classes and functions for calculating cluster scaling relations, including mass-richness and mass-concentration relations from the literature, as well as the surface mass density $\\Sigma(R)$ and differential surface mass density $\\Delta\\Sigma(R)$...

  11. How to reliably detect molecular clusters and nucleation mode particles with Neutral cluster and Air Ion Spectrometer (NAIS)

    Science.gov (United States)

    Manninen, Hanna E.; Mirme, Sander; Mirme, Aadu; Petäjä, Tuukka; Kulmala, Markku

    2016-08-01

    To understand the very first steps of atmospheric particle formation and growth processes, information on the size where the atmospheric nucleation and cluster activation occurs, is crucially needed. The current understanding of the concentrations and dynamics of charged and neutral clusters and particles is based on theoretical predictions and experimental observations. This paper gives a standard operation procedure (SOP) for Neutral cluster and Air Ion Spectrometer (NAIS) measurements and data processing. With the NAIS data, we have improved the scientific understanding by (1) direct detection of freshly formed atmospheric clusters and particles, (2) linking experimental observations and theoretical framework to understand the formation and growth mechanisms of aerosol particles, and (3) parameterizing formation and growth mechanisms for atmospheric models. The SOP provides tools to harmonize the world-wide measurements of small clusters and nucleation mode particles and to verify consistent results measured by the NAIS users. The work is based on discussions and interactions between the NAIS users and the NAIS manufacturer.

  12. The rotation of Galaxy Clusters

    CERN Document Server

    Tovmassian, Hrant M

    2015-01-01

    The method for detection of the galaxy cluster rotation based on the study of distribution of member galaxies with velocities lower and higher of the cluster mean velocity over the cluster image is proposed. The search for rotation is made for flat clusters with $a/b>1.8$ and BMI type clusters which are expected to be rotating. For comparison there were studied also round clusters and clusters of NBMI type, the second by brightness galaxy in which does not differ significantly from the cluster cD galaxy. Seventeen out of studied 65 clusters are found to be rotating. It was found that the detection rate is sufficiently high for flat clusters, over 60\\%, and clusters of BMI type with dominant cD galaxy, ~ 35%. The obtained results show that clusters were formed from the huge primordial gas clouds and preserved the rotation of the primordial clouds, unless they did not have merging with other clusters and groups of galaxies, in the result of which the rotation has been prevented.

  13. Angular cheilitis occurring during orthodontic treatment: a case series.

    Science.gov (United States)

    Cross, David L; Short, Laura J

    2008-12-01

    Clinical experience has shown that angular cheilitis can occur during orthodontic treatment and may persist into retention, but the incidence of the condition is unknown. The purpose of this paper is to increase the awareness among clinicians of angular cheilitis occurring during orthodontic treatment. It also proposes a treatment regime which may be used.

  14. Photoionization of rare gas clusters

    Science.gov (United States)

    Zhang, Huaizhen

    This thesis concentrates on the study of photoionization of van der Waals clusters with different cluster sizes. The goal of the experimental investigation is to understand the electronic structure of van der Waals clusters and the electronic dynamics. These studies are fundamental to understand the interaction between UV-X rays and clusters. The experiments were performed at the Advanced Light Source at Lawrence Berkeley National Laboratory. The experimental method employs angle-resolved time-of-flight photoelectron spectrometry, one of the most powerful methods for probing the electronic structure of atoms, molecules, clusters and solids. The van der Waals cluster photoionization studies are focused on probing the evolution of the photoelectron angular distribution parameter as a function of photon energy and cluster size. The angular distribution has been known to be a sensitive probe of the electronic structure in atoms and molecules. However, it has not been used in the case of van der Waals clusters. We carried out outer-valence levels, inner-valence levels and core-levels cluster photoionization experiments. Specifically, this work reports on the first quantitative measurements of the angular distribution parameters of rare gas clusters as a function of average cluster sizes. Our findings for xenon clusters is that the overall photon-energy-dependent behavior of the photoelectrons from the clusters is very similar to that of the corresponding free atoms. However, distinct differences in the angular distribution point at cluster-size-dependent effects were found. For krypton clusters, in the photon energy range where atomic photoelectrons have a high angular anisotropy, our measurements show considerably more isotropic angular distributions for the cluster photoelectrons, especially right above the 3d and 4p thresholds. For the valence electrons, a surprising difference between the two spin-orbit components was found. For argon clusters, we found that the

  15. Quantum phase transition between cluster and antiferromagnetic states

    CERN Document Server

    Son, Wonmin; Fazio, Rosario; Hamma, Alioscia; Pascazio, Saverio; Vedral, Vlatko

    2011-01-01

    We study a Hamiltonian system describing a three spin-1/2 cluster-like interaction competing with an Ising-like exchange. We show that the ground state in the cluster phase possesses symmetry protected topological order. A continuous quantum phase transition occurs as result of the competition between the cluster and Ising terms. At the critical point the Hamiltonian is self-dual. The geometric entanglement is also studied. Our findings in one dimension corroborate the analysis of the two dimensional generalization of the system, indicating, at a mean field level, the presence of a direct transition between an antiferromagnetic and a valence bond solid ground state.

  16. Single-cluster dynamics for the random-cluster model

    NARCIS (Netherlands)

    Deng, Y.; Qian, X.; Blöte, H.W.J.

    2009-01-01

    We formulate a single-cluster Monte Carlo algorithm for the simulation of the random-cluster model. This algorithm is a generalization of the Wolff single-cluster method for the q-state Potts model to noninteger values q>1. Its results for static quantities are in a satisfactory agreement with those

  17. Single-cluster dynamics for the random-cluster model

    NARCIS (Netherlands)

    Deng, Y.; Qian, X.; Blöte, H.W.J.

    2009-01-01

    We formulate a single-cluster Monte Carlo algorithm for the simulation of the random-cluster model. This algorithm is a generalization of the Wolff single-cluster method for the q-state Potts model to noninteger values q>1. Its results for static quantities are in a satisfactory agreement with those

  18. Hierarchical Formation of Galactic Clusters

    CERN Document Server

    Elmegreen, B G

    2006-01-01

    Young stellar groupings and clusters have hierarchical patterns ranging from flocculent spiral arms and star complexes on the largest scale to OB associations, OB subgroups, small loose groups, clusters and cluster subclumps on the smallest scales. There is no obvious transition in morphology at the cluster boundary, suggesting that clusters are only the inner parts of the hierarchy where stars have had enough time to mix. The power-law cluster mass function follows from this hierarchical structure: n(M_cl) M_cl^-b for b~2. This value of b is independently required by the observation that the summed IMFs from many clusters in a galaxy equals approximately the IMF of each cluster.

  19. Nuclear Cluster Aspects in Astrophysics

    Science.gov (United States)

    Kubono, Shigeru

    2010-03-01

    The role of nuclear clustering is discussed for nucleosynthesis in stellar evolution with Cluster Nucleosynthesis Diagram (CND) proposed before. Special emphasis is placed on α-induced stellar reactions together with molecular states for O and C burning.

  20. Eclipsing binaries in open clusters

    DEFF Research Database (Denmark)

    Southworth, John; Clausen, J.V.

    2006-01-01

    Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

  1. Observations of Distant Clusters

    Science.gov (United States)

    Donahue, Megan

    2004-01-01

    The is the proceedings and papers supported by the LTSA grant: Homer, D. J.\\& Donahue, M. 2003, in "The Emergence of Cosmic Structure": 13'h Astrophysics Conference Proceedings, Vol. 666,3 1 1-3 14, (AIP). Baumgartner, W. H., Loewenstein, M., Horner, D. J., Mushotzky, R. F. 2003, HEAD- AAS, 35.3503. Homer, D. J. , Donahue, M., Voit G. M. 2003, HEAD-AAS, 35.1309. Nowak, M. A., Smith, B., Donahue, M., Stocke, J. 2003, HEAD-AAS, 35.1316. Scott, D., Borys, C., Chapman, S. C., Donahue, M., Fahlman, G. G., Halpem, M. Newbury, P. 2002, AAS, 128.01. Jones, L. R. et al. 2002, A new era in cosmology, ASP Conference Proceedings, Vol. 283, p. 223 Donahue, M., Daly, R. A., Homer, D. J. 2003, ApJ, 584, 643, Constraints on the Cluster Environments and Hotspot magnetic field strengths for radio sources 3280 and 3254. Donahue, M., et al. 2003, ApJ, 598, 190. The mass, baryonic fraction, and x-ray temperature of the luminous, high-redshift cluster of galaxies MS045 1.6-0305 Perlman, E. S. et al. 2002, ApJS, 140, 256. Smith, B. J., Nowak, M., Donahue, M., Stocke, J. 2003, AJ, 126, 1763. Chandra Observations of the Interacting NGC44 10 Group of Galaxies. Postman, M., Lauer, T. R., Oegerle, W., Donahue, M. 2002, ApJ, 579, 93. The KPNO/deep-range cluster survey I. The catalog and space density of intermediate-redshift clusters. Molnar, S. M., Hughes, J. P., Donahue, M., Joy, M. 2002, ApJ, 573, L91, Chandra Observations of Unresolved X-Ray Sources around Two Clusters of Galaxies. Donahue, M., Mack, J., 2002 NewAR, 46, 155, HST NIcmos and WFPC2 observations of molecular hydrogen and dust around cooling flows. Koekemoer, A. M. et al. 2002 NewAR, 46, 149, Interactions between the A2597 central radio source and dense gas host galaxy. Donahue, M. et al. 2002 ApJ, 569,689, Distant cluster hunting II.

  2. The Assembly of Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Berrier, Joel C.; Stewart, Kyle R.; Bullock, James S.; Purcell, Chris W.; Barton, Elizabeth J.; Wechsler, Risa H.

    2008-05-16

    We study the formation of fifty-three galaxy cluster-size dark matter halos (M = 10{sup 14.0-14.76} M{sub {circle_dot}}) formed within a pair of cosmological {Lambda}CDM N-body simulations, and track the accretion histories of cluster subhalos with masses large enough to host {approx} 0.1L{sub *} galaxies. By associating subhalos with cluster galaxies, we find the majority of galaxies in clusters experience no 'pre-processing' in the group environment prior to their accretion into the cluster. On average, {approx} 70% of cluster galaxies fall into the cluster potential directly from the field, with no luminous companions in their host halos at the time of accretion; and less than {approx} 12% are accreted as members of groups with five or more galaxies. Moreover, we find that cluster galaxies are significantly less likely to have experienced a merger in the recent past ({approx}< 6 Gyr) than a field halo of the same mass. These results suggest that local, cluster processes like ram-pressure stripping, galaxy harassment, or strangulation play the dominant role in explaining the difference between cluster and field populations at a fixed stellar mass; and that pre-evolution or past merging in the group environment is of secondary importance for setting cluster galaxy properties for most clusters. The accretion times for z = 0 cluster members are quite extended, with {approx} 20% incorporated into the cluster halo more than 7 Gyr ago and {approx} 20% within the last 2 Gyr. By comparing the observed morphological fractions in cluster and field populations, we estimate an approximate time-scale for late-type to early-type transformation within the cluster environment to be {approx} 6 Gyr.

  3. [Cluster analysis in biomedical researches].

    Science.gov (United States)

    Akopov, A S; Moskovtsev, A A; Dolenko, S A; Savina, G D

    2013-01-01

    Cluster analysis is one of the most popular methods for the analysis of multi-parameter data. The cluster analysis reveals the internal structure of the data, group the separate observations on the degree of their similarity. The review provides a definition of the basic concepts of cluster analysis, and discusses the most popular clustering algorithms: k-means, hierarchical algorithms, Kohonen networks algorithms. Examples are the use of these algorithms in biomedical research.

  4. Textile Industrial Clusters in China

    Institute of Scientific and Technical Information of China (English)

    Nie Ting

    2010-01-01

    @@ "National Textile Industry Cluster Development Seminar" convened,held by China National Textile and Apparel Council,23 cities and towns were awarded as China's Textile Industry Cluster Pilot District.By far,China's textile industrial clusters have grown to 164,which indicate a quick and gorgeous development.These textile industrial clusters have a great impact on the local economy and even the whole national textile industry's development.

  5. Practical Introduction to Clustering Data

    CERN Document Server

    Hartmann, Alexander K

    2016-01-01

    Data clustering is an approach to seek for structure in sets of complex data, i.e., sets of "objects". The main objective is to identify groups of objects which are similar to each other, e.g., for classification. Here, an introduction to clustering is given and three basic approaches are introduced: the k-means algorithm, neighbour-based clustering, and an agglomerative clustering method. For all cases, C source code examples are given, allowing for an easy implementation.

  6. Metalloid Aluminum Clusters with Fluorine

    Science.gov (United States)

    2016-12-01

    molecular-scale metalloid clusters as a way to achieve very rapid rates of metal combustion. These clusters contain a mixture of low-valence metals...using molecular-scale metalloid clusters as a way to achieve very rapid rates of metal combustion. These clusters contain a mixture of low- valence...25 Table 2. Calculated binding energy, HOMO/LUMO gap and Fermi energy

  7. Massive star clusters in galaxies

    CERN Document Server

    Harris, William E

    2009-01-01

    The ensemble of all star clusters in a galaxy constitutes its star cluster system. In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCSs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GCS research, and highlight some of the outstanding questions that are emerging from recent work.

  8. Lithium-Rich Giants in Globular Clusters

    CERN Document Server

    Kirby, Evan N; Zhang, Andrew J; Hong, Jerry; Guo, Michelle; Guo, Rachel; Cohen, Judith G; Cunha, Katia

    2016-01-01

    Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron-Fowler conveyor, but the existence of Li-rich, low-mass red giant branch (RGB) stars is puzzling. Globular clusters are the best sites to examine this phenomenon because it is straightforward to determine membership in the cluster and to identify the evolutionary state of each star. In 72 hours of Keck/DEIMOS exposures in 25 clusters, we found four Li-rich RGB and two Li-rich AGB stars. There were 1696 RGB and 125 AGB stars with measurements or upper limits consistent with normal abundances of Li. Hence, the frequency of Li-richness in globular clusters is (0.2 +/- 0.1)% for the RGB, (1.6 +/- 1.1)% for the AGB, and (0.3 +/- 0.1)% for all giants. Because the Li-rich RGB stars are on the lower RGB, Li self-generation mechanisms proposed to occur at the luminosity function bump or He core flash cannot explain these four lower RGB stars. We propo...

  9. Cosmic Web Type Dependence of Halo Clustering

    CERN Document Server

    Fisher, J D

    2016-01-01

    We use the Millennium simulation to show that halo clustering varies significantly with cosmic web type. Halos are classified as node, filament, sheet and void halos based on the eigenvalue decomposition of the velocity shear tensor. This classification allows us to examine the clustering of halos as a function of web type in different mass ranges. We find that node halos show positive bias for all mass ranges probed, even for 10^11 and 10^12 Msun/h mass bins where the clustering of the entire halo sample is anti-biased. In all mass bins filament halos show negligible bias, whereas void and sheet halos are anti-biased. The zero-crossing of the void and sheet correlation functions occur at much smaller scales Mpc/h when compared to 5the same correlation functions for the entire halo sample. Our results suggest that the mass dependence of halo clustering is rooted in the composition of web types in the mass bin. The substantial fraction of node type halos for halo masses 2 x 10^13 Msun/h leads to positive bias....

  10. Enhanced Momentum Feedback from Clustered Supernovae

    CERN Document Server

    Gentry, Eric S; Dekel, Avishai; Madau, Piero

    2016-01-01

    Massive stars are typically in star clusters and live short lives, so the supernovae (SNe) they produce are clustered in space and time. Since the amount of momentum that SNe can deliver to the interstellar medium depends on how their outflowing remnants make the transition from adiabatic to radiative, this clustering may alter the momentum budget per SN, an effect we systematically explore over a large parameter space. We perform a parameter study of 1D hydrodynamic simulations, varying the number of SNe, and the background gas metallicity and density. For a few SNe, we find that the asymptotic momentum scales superlinearly with the number of SNe. As a result, the asymptotic momentum per SN can be an order of magnitude greater than that delivered by isolated SNe, with a maximum efficiency occurring for clusters that produce ~10-100 SNe. Adequately capturing this effect in simulations requires very high resolution to avoid over-cooling (a typical resolution for our simulations is 0.3 pc). We show that inadequ...

  11. THE NEXT GENERATION VIRGO CLUSTER SURVEY. IV. NGC 4216: A BOMBARDED SPIRAL IN THE VIRGO CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Paudel, Sanjaya; Duc, Pierre-Alain; Ferriere, Etienne [Laboratoire AIM Paris-Saclay, CNRS/INSU, Universite Paris Diderot, CEA/IRFU/SAp, F-91191 Gif-sur-Yvette Cedex (France); Cote, Patrick; Ferrarese, Laura; Gwyn, Stephen D. J.; MacArthur, Lauren A. [National Research Council of Canada, Victoria, BC V9E 2E7 (Canada); Cuillandre, Jean-Charles [Canada-France-Hawaii Telescope Corporation, Kamuela, HI 96743 (United States); Mihos, J. Christopher [Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States); Vollmer, Bernd [Observatoire Astronomique, Universite de Strasbourg and CNRS UMR 7550, 11 rue de l' Universite, F-67000 Strasbourg (France); Balogh, Michael L. [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Carlberg, Ray G. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Boissier, Samuel; Boselli, Alessandro [Aix Marseille Universite, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Durrell, Patrick R. [Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, OH 44555 (United States); Emsellem, Eric; Michel-Dansac, Leo [Universite de Lyon 1, CRAL, Observatoire de Lyon, CNRS UMR 5574, 9 av. Charles Andre, F-69230 Saint-Genis Laval (France); Mei, Simona; Van Driel, Wim, E-mail: sanjaya.paudel@cea.fr [GEPI, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 Place J. Janssen, F-92190 Meudon Cedex (France)

    2013-04-20

    The final stages of mass assembly of present-day massive galaxies are expected to occur through the accretion of multiple satellites. Cosmological simulations thus predict a high frequency of stellar streams resulting from this mass accretion around the massive galaxies in the Local Volume. Such tidal streams are difficult to observe, especially in dense cluster environments, where they are readily destroyed. We present an investigation into the origins of a series of interlaced narrow filamentary stellar structures, loops and plumes in the vicinity of the Virgo Cluster, edge-on spiral galaxy, NGC 4216 that were previously identified by the Blackbird telescope. Using the deeper, higher-resolution, and precisely calibrated optical CFHT/MegaCam images obtained as part of the Next Generation Virgo Cluster Survey (NGVS), we confirm the previously identified features and identify a few additional structures. The NGVS data allowed us to make a physical study of these low surface brightness features and investigate their origin. The likely progenitors of the structures were identified as either already cataloged Virgo Cluster Catalog dwarfs or newly discovered satellites caught in the act of being destroyed. They have the same g - i color index and likely contain similar stellar populations. The alignment of three dwarfs along an apparently single stream is intriguing, and we cannot totally exclude that these are second-generation dwarf galaxies being born inside the filament from the debris of an original dwarf. The observed complex structures, including in particular a stream apparently emanating from a satellite of a satellite, point to a high rate of ongoing dwarf destruction/accretion in the region of the Virgo Cluster where NGC 4216 is located. We discuss the age of the interactions and whether they occurred in a group that is just falling into the cluster and shows signs of the so-called pre-processing before it gets affected by the cluster environment, or in a

  12. Spatial temporal clustering for hotspot using kulldorff scan statistic method (KSS): A case in Riau Province

    Science.gov (United States)

    Hudjimartsu, S. A.; Djatna, T.; Ambarwari, A.; Apriliantono

    2017-01-01

    The forest fires in Indonesia occurs frequently in the dry season. Almost all the causes of forest fires are caused by the human activity itself. The impact of forest fires is the loss of biodiversity, pollution hazard and harm the economy of surrounding communities. To prevent fires required the method, one of them with spatial temporal clustering. Spatial temporal clustering formed grouping data so that the results of these groupings can be used as initial information on fire prevention. To analyze the fires, used hotspot data as early indicator of fire spot. Hotspot data consists of spatial and temporal dimensions can be processed using the Spatial Temporal Clustering with Kulldorff Scan Statistic (KSS). The result of this research is to the effectiveness of KSS method to cluster spatial hotspot in a case within Riau Province and produces two types of clusters, most cluster and secondary cluster. This cluster can be used as an early fire warning information.

  13. Mechanisms contributing to cluster formation in the inferior olivary nucleus in brainstem slices from postnatal mice

    DEFF Research Database (Denmark)

    Kølvraa, Mathias; Müller, Felix C; Jahnsen, Henrik

    2014-01-01

    with glutamate. Induced clusters were inhibited by tetrodotoxin, carbenoxelone and 18β-glycyrrhetinic acid, suggesting that sodium action potentials and electrical coupling are involved in glutamate-induced cluster formation, which could also be induced by activation of N-methyl-d-aspartate and α-amino-3-hydroxy......-5-methyl-4-isoxazolepropionic acid receptors. Spikelets and a small transient depolarizing response were observed during glutamate-induced cluster formation. Calcium transients spread with decreasing velocity during cluster formation, and somatic action potentials and cluster formation...... are accompanied by large dendritic calcium transients. In conclusion, cluster formation depends on gap junctions, sodium action potentials and spontaneous clusters occur randomly throughout the IO. The relative slow signal spread during cluster formation, combined with a strong dendritic influx of calcium, may...

  14. Uncertainties in the cluster-cluster correlation function

    Energy Technology Data Exchange (ETDEWEB)

    Ling, E.N.; Barrow, J.D.; Frenk, C.S.

    1986-12-01

    The bootstrap resampling technique is applied to estimate sampling errors and significance levels of the two-point correlation functions determined for a subset of the CfA redshift survey of galaxies and a redshift sample of 104 Abell clusters. The angular correlation functions is also calculated for a sample of 1664 Abell clusters. The standard errors for the Abell data are found to be considerably larger than quoted 'Poisson errors'. The enhancement of cluster clustering over galaxy clustering is statistically significant in the presence of resampling errors.

  15. A psycho-educational HIV/STI prevention intervention for internally displaced women in Leogane, Haiti: results from a non-randomized cohort pilot study.

    Directory of Open Access Journals (Sweden)

    Carmen H Logie

    Full Text Available BACKGROUND: Little evidence exists regarding efficacious HIV and sexually transmitted infections (STI prevention interventions with internally displaced populations. Internally displaced women are at elevated risk for HIV/STI due to limited access to health services, heightened poverty and social network breakdown. The FASY (Famn an Aksyon Pou Sante' Yo (Women Taking Action For Their Health study examined the effectiveness of a peer health worker (PHW delivered psycho-educational HIV/STI pilot study with internally displaced women in Leogane, Haiti. METHOD: This was a non-randomized cohort pilot study. Participants completed a computer-assisted pre-test programmed on Android tablet PCs followed by an HIV/STI educational video-based session and a 6-week psycho-educational group program of weekly meetings. Participants completed a post-test upon completion of group sessions. The primary outcome was HIV knowledge; our pre-specified index of clinically significant change was an effect size of 0.30. Secondary outcomes included: STI knowledge, condom use, social support, resilient coping, depression and relationship control. We used mixed-effects regression to calculate mean outcome pre-post score change. This study was registered (clinicaltrials.gov, NCT01492829. RESULTS: Between January 1-April 30, 2012 we assigned 200 participants to the study. The majority of participants (n = 176, 88% completed the study and were followed up at 8 weeks, finishing April 30, 2012. Adjusted for socio-demographic characteristics, HIV knowledge (β = 4.81; 95% CI 4.36-5.26, STI knowledge (β = 0.84; 95% CI 0.70-0.99, condom use (AOR = 4.05, 95% CI 1.86-8.83, and depression (β = -0.63, 95% CI -0.88--0.39 scores showed statistically significant change post-intervention (p<0.05. CONCLUSIONS: This pilot study evaluated a PHW psycho-educational HIV/STI prevention intervention among internally displaced women in post-earthquake Haiti. Pilot studies are an important

  16. Evaluation of an advanced pressure ulcer management protocol followed by trained wound, ostomy, and continence nurses: a non-randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Kaitani T

    2015-02-01

    Full Text Available Toshiko Kaitani,1 Gojiro Nakagami,2 Junko Sugama,3 Masahiro Tachi,4 Yutaka Matsuyama,5 Yoshiki Miyachi,6 Takashi Nagase,2 Yukie Takemura,7 Hiromi Sanada2 1School of Nursing, Sapporo City University, Hokkaido, Japan; 2Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 3Department of Clinical Nursing, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan; 4Department of Plastic Surgery, Tohoku University Graduate School of Medicine, Miyagi, Japan; 5Department of Biostatistics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 6Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan; 7Department of Nursing, Research Hospital, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan Aims and objectives: We investigated the effectiveness and safety of an advanced pressure ulcer (PU management protocol comprising 1 ultrasonography to assess the deep tissue, 2 use of a non-contact thermometer to detect critical colonization, 3 conservative sharp debridement, 4 dressing selection, 5 negative pressure wound therapy, and 6 vibration therapy in comparison with those of a conventional approach. Each protocol was followed by trained wound, ostomy, and continence nurses (WOCNs. Background: At present, there is no systematic PU management protocol for nurses that includes appropriate assessment and intervention techniques for deep tissue injury and critical colonization. In Japan, there is no such protocol that the nurses can follow without a physician’s orders. Design and methods: This was a prospective non-randomized controlled trial. Over a 3-week period, we evaluated the effectiveness of an advanced protocol by comparing the PU severity and healing on the basis of the DESIGN-R scale and presence of patients' discomfort. We recruited ten WOCNs to follow

  17. Effects of an Integrated ‘Fast Track’ Rehabilitation Service for Multi-Trauma Patients: A Non-Randomized Clinical Trial in the Netherlands

    Science.gov (United States)

    Bouman, Ans I. E.; Hemmen, Bea; Evers, Silvia M. A. A.; van de Meent, Henk; Ambergen, Ton; Vos, Pieter E.; Brink, Peter R. G.; Seelen, Henk A. M.

    2017-01-01

    Objectives The effects on health related outcomes of a newly-developed rehabilitation program, called ‘supported Fast Track multi-trauma rehabilitation service’ (Fast Track), were evaluated in comparison with conventional trauma rehabilitation service (Care as Usual). Methods Prospective, multi-center, non-randomized controlled study. Between 2009 and 2012, 132 adult multi-trauma patients were included: 65 Fast Track and 67 Care as Usual patients with an Injury Severity Score ≥16, complex multiple injuries in several extremities or complex pelvic and/or acetabulum fractures. The Fast Track program involved: integrated coordination between trauma surgeon and rehabilitation physician, shorter stay in hospital with faster transfer to a specialized trauma rehabilitation unit, earlier start of multidisciplinary treatment and ‘non-weight bearing’ mobilization. Primary outcomes were functional status (FIM) and quality of life (SF-36) measured through questionnaires at baseline, 3, 6, 9 and 12 months post-trauma. Outcomes were analyzed using a linear mixed-effects regression model. Results The FIM scores significantly increased between 0 and 3 months (p<0.001) for both groups showing that they had improved overall, and continued to improve between 3 and 6 months for Fast Track (p = 0.04) and between 3 and 9 months for Care as Usual (p = 0.03). SF-36 scores significantly improved in both groups between 3 and 6 months (Fast Track, p<0.001; Care as Usual, p = 0.01). At 12 months, SF-36 scores were still below (self-reported) baseline measurements of patient health prior to the accident. However, the FIM and SF-36 scores differed little between the groups at any of the measured time points. Conclusion Both Fast Track and Care as Usual rehabilitation programs were effective in that multi-trauma patients improved their functional status and quality of life. A faster (maximum) recovery in functional status was observed for Fast Track at 6 months compared to 9 months for

  18. TP53 status and taxane-platinum versus platinum-based therapy in ovarian cancer patients: A non-randomized retrospective study

    Directory of Open Access Journals (Sweden)

    Markowska Janina

    2008-01-01

    Full Text Available Abstract Background Taxane-platinum therapy (TP has replaced platinum-based therapy (PC or PAC, DNA damaging chemotherapy in the postoperative treatment of ovarian cancer patients; however, it is not always effective. TP53 protein plays a differential role in response to DNA-damaging agents and taxanes. We sought to define profiles of patients who benefit the most from TP and also of those who can be treated with PC. Methods We compared the effectiveness of PC/PAC (n = 253 and TP (n = 199 with respect to tumor TP53 accumulation in ovarian cancer patients with FIGO stage IIB-IV disease; this was a non-randomized retrospective study. Immunohistochemical analysis was performed on 452 archival tumors; univariate and multivariate analysis by the Cox's and logistic regression models was performed in all patients and in subgroups with [TP53(+] and without TP53 accumulation [TP53(-]. Results The advantage of taxane-platinum therapy over platinum-based therapy was seen in the TP53(+, and not in the TP53(- group. In the TP53(+ group taxane-platinum therapy enhanced the probability of complete remission (p = .018, platinum sensitivity (p = .014, platinum highly sensitive response (p = .038 and longer survival (OS, p = .008. Poor tumor differentiation diminished the advantage from taxane-platinum therapy in the TP53(+ group. In the TP53(- group PC/PAC was at least equally efficient as taxane-platinum therapy and it enhanced the chance of platinum highly sensitive response (p = .010. However, in the TP53(- group taxane-platinum therapy possibly diminished the risk of death in patients over 53 yrs (p = .077. Among factors that positively interacted with taxane-platinum therapy in some analyses were endometrioid and clear cell type, FIGO III stage, bulky residual tumor, more advanced age of patient and moderate tumor differentiation. Conclusion Our results suggest that taxane-platinum therapy is particularly justified in patients with TP53(+ tumors or older

  19. Perioperative and long-term results after left pancreatectomy: a single-institution, non-randomized, comparative study between open and laparoscopic approach.

    Science.gov (United States)

    Butturini, Giovanni; Partelli, Stefano; Crippa, Stefano; Malleo, Giuseppe; Rossini, Roberto; Casetti, Luca; Melotti, Gian Luigi; Piccoli, Micaela; Pederzoli, Paolo; Bassi, Claudio

    2011-09-01

    Laparoscopic left pancreatic resections are being increasingly performed. In this study, we provide a nonrandomized comparison between laparoscopic and open left pancreatectomy (OLP) for benign and borderline tumors, focusing on both perioperative and long-term results. Demographic, pathologic, and perioperative details from patients who underwent laparoscopic and OLP between 1999 and 2006 were retrieved from our database and analyzed. Long-term results, including resume to full-time work, occurrence of incisional hernias, and incidence of exocrine and endocrine insufficiency also were evaluated. A total of 116 patients were included in the analysis; 43 (37.1%) were managed laparoscopically and 73 (62.9%) underwent the open procedure. There were no significant differences regarding clinical and pathological data. All of the resections attempted laparoscopically were completed. The rate of splenic preservation was significantly higher in the laparoscopic group (P = 0.0001). Postoperative outcomes were similar between the two groups. Longitudinal comparison between two time periods (1999-June 2004 vs. July 2004-2006) showed that pancreatic fistula and hospital stay significantly diminished over time in the laparoscopic group (P = 0.04 and P = 0.004, respectively). Median follow-up was 53 months. The incidence of exocrine insufficiency and incisional hernias was significantly higher after open resections (both P = 0.05). After hospital discharge, median time to resume full-time work was 6 weeks in the open group and 3 weeks after laparoscopic resections (P < 0.0001). Laparoscopy also resulted as an independent factor for an early resume to full-time activities in the multivariate analysis (P < 0.0001). Laparoscopic left pancreatectomy is a safe procedure for benign and borderline tumors, with similar perioperative outcomes compared with the open procedure. In the long term, the laparoscopic approach is likely to be superior thanks to a more rapid resume

  20. Stellar populations in star clusters

    Science.gov (United States)

    Li, Cheng-Yuan; de Grijs, Richard; Deng, Li-Cai

    2016-12-01

    Stellar populations contain the most important information about star cluster formation and evolution. Until several decades ago, star clusters were believed to be ideal laboratories for studies of simple stellar populations (SSPs). However, discoveries of multiple stellar populations in Galactic globular clusters have expanded our view on stellar populations in star clusters. They have simultaneously generated a number of controversies, particularly as to whether young star clusters may have the same origin as old globular clusters. In addition, extensive studies have revealed that the SSP scenario does not seem to hold for some intermediate-age and young star clusters either, thus making the origin of multiple stellar populations in star clusters even more complicated. Stellar population anomalies in numerous star clusters are well-documented, implying that the notion of star clusters as true SSPs faces serious challenges. In this review, we focus on stellar populations in massive clusters with different ages. We present the history and progress of research in this active field, as well as some of the most recent improvements, including observational results and scenarios that have been proposed to explain the observations. Although our current ability to determine the origin of multiple stellar populations in star clusters is unsatisfactory, we propose a number of promising projects that may contribute to a significantly improved understanding of this subject.

  1. Geographic Projection of Cluster Composites

    NARCIS (Netherlands)

    Nerbonne, J.; Bosveld-de Smet, L.M.; Kleiweg, P.; Blackwell, A.; Marriott, K.; Shimojima, A.

    2004-01-01

    A composite cluster map displays a fuzzy categorisation of geographic areas. It combines information from several sources to provide a visualisation of the significance of cluster borders. The basic technique renders the chance that two neighbouring locations are members of different clusters as the

  2. Clustering objects from multiple collections

    NARCIS (Netherlands)

    Hollink, V.; van Someren, M.; de Boer, V.

    2009-01-01

    Clustering methods cluster objects on the basis of a similarity measure between the objects. In clustering tasks where the objects come from more than one collection often part of the similarity results from features that are related to the collections rather than features that are relevant for the

  3. Privacy-preserving distributed clustering

    NARCIS (Netherlands)

    Erkin, Z.; Veugen, T.; Toft, T.; Lagendijk, R.L.

    2013-01-01

    Clustering is a very important tool in data mining and is widely used in on-line services for medical, financial and social environments. The main goal in clustering is to create sets of similar objects in a data set. The data set to be used for clustering can be owned by a single entity, or in some

  4. Clustering Objects from Multiple Collections

    NARCIS (Netherlands)

    Hollink, V.; Someren, M. van; Boer, V. de

    2009-01-01

    Clustering methods cluster objects on the basis of a similarity measure between the objects. In clustering tasks where the objects come from more than one collection often part of the similarity results from features that are related to the collections rather than features that are relevant for the

  5. Clustering objects from multiple collections

    NARCIS (Netherlands)

    Hollink, V.; van Someren, M.; de Boer, V.

    2009-01-01

    Clustering methods cluster objects on the basis of a similarity measure between the objects. In clustering tasks where the objects come from more than one collection often part of the similarity results from features that are related to the collections rather than features that are relevant for the

  6. Recovery Rate of Clustering Algorithms

    NARCIS (Netherlands)

    Li, Fajie; Klette, Reinhard; Wada, T; Huang, F; Lin, S

    2009-01-01

    This article provides a simple and general way for defining the recovery rate of clustering algorithms using a given family of old clusters for evaluating the performance of the algorithm when calculating a family of new clusters. Under the assumption of dealing with simulated data (i.e., known old

  7. Tune Your Brown Clustering, Please

    DEFF Research Database (Denmark)

    Derczynski, Leon; Chester, Sean; Bøgh, Kenneth Sejdenfaden

    2015-01-01

    explore the dynamic between the input corpus size, chosen number of classes, and quality of the resulting clusters, which has an impact for any approach using Brown clustering. In every scenario that we examine, our results reveal that the values most commonly used for the clustering are sub-optimal....

  8. Are megaquakes clustered?

    CERN Document Server

    Daub, Eric G; Guyer, Robert A; Johnson, Paul A

    2012-01-01

    We study statistical properties of the number of large earthquakes over the past century. We analyze the cumulative distribution of the number of earthquakes with magnitude larger than threshold M in time interval T, and quantify the statistical significance of these results by simulating a large number of synthetic random catalogs. We find that in general, the earthquake record cannot be distinguished from a process that is random in time. This conclusion holds whether aftershocks are removed or not, except at magnitudes below M = 7.3. At long time intervals (T = 2-5 years), we find that statistically significant clustering is present in the catalog for lower magnitude thresholds (M = 7-7.2). However, this clustering is due to a large number of earthquakes on record in the early part of the 20th century, when magnitudes are less certain.

  9. Outskirts of Galaxy Clusters

    CERN Document Server

    Reiprich, Thomas H; Ettori, Stefano; Israel, Holger; Lovisari, Lorenzo; Molendi, Silvano; Pointecouteau, Etienne; Roncarelli, Mauro

    2013-01-01

    Until recently, only about 10% of the total intracluster gas volume had been studied with high accuracy, leaving a vast region essentially unexplored. This is now changing and a wide area of hot gas physics and chemistry awaits discovery in galaxy cluster outskirts. Also, robust large-scale total mass profiles and maps are within reach. First observational and theoretical results in this emerging field have been achieved in recent years with sometimes surprising findings. Here, we summarize and illustrate the relevant underlying physical and chemical processes and review the recent progress in X-ray, Sunyaev--Zel'dovich, and weak gravitational lensing observations of cluster outskirts, including also brief discussions of technical challenges and possible future improvements.

  10. Refractory chronic cluster headache

    DEFF Research Database (Denmark)

    Mitsikostas, Dimos D; Edvinsson, Lars; Jensen, Rigmor H

    2014-01-01

    Chronic cluster headache (CCH) often resists to prophylactic pharmaceutical treatments resulting in patients' life damage. In this rare but pragmatic situation escalation to invasive management is needed but framing criteria are lacking. We aimed to reach a consensus for refractory CCH definition...... for clinical and research use. The preparation of the final consensus followed three stages. Internal between authors, a larger between all European Headache Federation members and finally an international one among all investigators that have published clinical studies on cluster headache the last five years....... Eighty-five investigators reached by email. Proposed criteria were in the format of the International Classification of Headache Disorders III-beta (description, criteria, notes, comments and references). Following this evaluation eight drafts were prepared before the final. Twenty-four (28...

  11. The Baltimore and Utrecht models for cluster dissolution

    CERN Document Server

    Lamers, Henny J G L M

    2008-01-01

    The analysis of the age distributions of star cluster samples of different galaxies has resulted in two very different empirical models for the dissolution of star clusters: the Baltimore model and the Utrecht model. I describe these two models and their differences. The Baltimore model implies that the dissolution of star clusters is mass independent and that about 90% of the clusters are destroyed each age dex, up to an age of about a Gyr, after which point mass-dependent dissolution from two-body relaxation becomes the dominant mechanism. In the Utrecht model, cluster dissolution occurs in three stages: (i) mass-independent infant mortality due to the expulsion of gas up to about 10 Myr; (ii) a phase of slow dynamical evolution with strong evolutionary fading of the clusters lasting up to about a Gyr; and (iii) a phase dominated by mass dependent-dissolution, as predicted by dynamical models. I describe the cluster age distributions for mass-limited and magnitude-limited cluster samples for both models. I ...

  12. Clustering of Parkinson disease: shared cause or coincidence?

    Science.gov (United States)

    Kumar, Ajit; Calne, Susan M; Schulzer, Michael; Mak, Edwin; Wszolek, Zbigniew; Van Netten, Chris; Tsui, Joseph K C; Stoessl, A Jon; Calne, Donald B

    2004-07-01

    The spatial and temporal pattern of excessive disease occurrence, termed clustering, may provide clues about the underlying etiology. To report the occurrence of 3 clusters of Parkinson disease (PD) in Canada. We determined the population groups containing the clusters, geographical limits, and duration of exposure to the specific environments. We tested whether there was an excessive presence of Parkinson disease by calculating the probability of the observed cases occurring under the null hypothesis that the disease developed independently and at random in cluster subjects. Results of genetic testing for mutations in the alpha-synuclein, parkin, tau genes, and spinocerebellar ataxia genes (SCA2 and SCA3) were negative. The probabilities of random occurrence (P values) in the 3 clusters were P = 7.9 x 10 (-7)for cluster 1, P = 2.6 x 10 (-7)for cluster 2, and P = 1.5 x 10 (-7)for cluster 3. Our findings indicate an important role for environmental causation in Parkinson disease. A possible role exists for environmental factors such as viral infection and toxins in the light of current evidence.

  13. [Childhood cancer epidemiology and available evidence on case clustering].

    Science.gov (United States)

    Maule, Milena; Terracini, Benedetto

    2016-01-01

    This paper introduces a Monograph on childhood cancer clusters addressed to Italian public health workers, paediatricians and paediatric oncologists, and the general public. Two issues have been underlined in most definitions of cancer clusters reported in the literature over the last 30 years. The first is the need for an unbiased methodological approach for the detection and the interpretation of clustering and of individual clusters. The other is the responsibility for scientists and public health workers to unravel suspicious events and to interact with the population in circumstances which may turn out to be false alarms. The relative weight given to epidemiological methods and to risk perception has varied between definitions of clusters given in different periods. In the field of childhood cancer clusters, epidemiological research has produced very little fresh knowledge. However, it is recognized that this is not a sufficient reason for refusing to pay attention to reports of perceived clusters. Models of spatio-temporal interactions according to Birch et al. (2000) are taken in consideration: the literature offers a very limited number of circumstances fitting such models. In Italy, over the years, only two childhood cancer clusters have been reported in the indexed literature, both of them regarded cases of acute lymphatic leukaemia and occurred in Sardinia in the Eighties and in the area of Roma in the Nineties. A possible reason for the paucity of reports (compared, for instance, to the UK scenario) is the limited availability of health statistics.

  14. Cu clustering stage before the crystallization in Fe-Si-B-Nb-Cu amorphous alloys

    DEFF Research Database (Denmark)

    Ohnuma, M.; Hono, K.; Onodera, H.

    1999-01-01

    The Cu clustering stage before the crystallization of Fe-Si-B-Nb-Cu amorphous alloys have been studied by three dimensional atom probe (3DAP) small-angle neutron scattering (SANS) and high sensitive differential calorimetry (DSC). Cu clustering occurs prior to the onset of the primary crystalliza......The Cu clustering stage before the crystallization of Fe-Si-B-Nb-Cu amorphous alloys have been studied by three dimensional atom probe (3DAP) small-angle neutron scattering (SANS) and high sensitive differential calorimetry (DSC). Cu clustering occurs prior to the onset of the primary...

  15. Computer Simulation of Ordering and Atom Clustering in Aging Binary Al-Li Alloy

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-ling; CHEN Zheng; WANG Yong-xin; HU Ming-juan

    2004-01-01

    Ordering and atom clustering in aging binary Al-Li alloy has been investigated by computer simulation through calculating the long range order (lro.) parameter and composition deviation order parameter from single-site occupation probabilities of Li atom. The results show that when the alloy lies in metastable region in the phase diagram ordering and atom clustering occur simultaneously. As the composition of the alloy increases ordering occurs earlier than atom clustering gradually. When the alloy lies in instable region atom clustering takes place after the congruent ordering completes. It has also been found that the incubation period of the phase transformation is shortened as the composition increases.

  16. Computer Simulation of Ordering and Atom Clustering in Aging Binary AI-Li Alloy

    Institute of Scientific and Technical Information of China (English)

    LIXiao-ling; CHENZheng; WANGYong-xin; HUMing-juan

    2004-01-01

    Ordering and atom clustering in aging binary Al-Li alloy has been investigated by computer simulation through calculating the long range order (lro.) parameter and composition deviation order parameter from single-site occupation probabilities of Li atom. The results show that when the alloy lies in metastable region in the phase diagram ordering and atom clustering occur simultaneously. As the composition of the alloy increases ordering occurs earlier than atom clustering gradually. When the alloy lies in instable region atom clustering takes place after the congruent ordering completes. It has also been found that the incubation period of the phase transformation is shortened as the composition increases.

  17. Astrophysics of galaxy clusters

    Science.gov (United States)

    Ettori, Stefano

    2016-07-01

    As the nodes of the cosmic web, clusters of galaxies trace the large-scale distribution of matter in the Universe. They are thus privileged sites in which to investigate the complex physics of structure formation. However, the complete story of how these structures grow, and how they dissipate the gravitational and non-thermal components of their energy budget over cosmic time, is still beyond our grasp. Most of the baryons gravitationally bound to the cluster's halo is in the form of a diffuse, hot, metal-enriched plasma that radiates primarily in the X-ray band. X-ray observations of the evolving cluster population provide a unique opportunity to address such fundamental open questions as: How do hot diffuse baryons accrete and dynamically evolve in dark matter potentials? How and when was the energy that we observe in the ICM generated and distributed? Where and when are heavy elements produced and how are they circulated? We will present the ongoing activities to define the strategy on how an X-ray observatory with large collecting area and an unprecedented combination of high spectral and angular resolution, such as Athena, can address these questions.

  18. Support Policies in Clusters: Prioritization of Support Needs by Cluster Members According to Cluster Life Cycle

    Directory of Open Access Journals (Sweden)

    Gulcin Salıngan

    2012-07-01

    Full Text Available Economic development has always been a moving target. Both the national and local governments have been facing the challenge of implementing the effective and efficient economic policy and program in order to best utilize their limited resources. One of the recent approaches in this area is called cluster-based economic analysis and strategy development. This study reviews key literature and some of the cluster based economic policies adopted by different governments. Based on this review, it proposes “the cluster life cycle” as a determining factor to identify the support requirements of clusters. A survey, designed based on literature review of International Cluster support programs, was conducted with 30 participants from 3 clusters with different maturity stage. This paper discusses the results of this study conducted among the cluster members in Eskişehir- Bilecik-Kütahya Region in Turkey on the requirement of the support to foster the development of related clusters.

  19. Clustering and Synchronization in an Array of Repulsively Coupled Phase Oscillators

    Institute of Scientific and Technical Information of China (English)

    LI Juan; WU Liang; ZHU Shi-Qun

    2007-01-01

    Clustering and synchronization in an array of repulsively coupled phase oscillators are numerically investigated. It is found that oscillators are divided into several clusters according to the symmetry in the structure.Synchronization occurs between oscillators in each cluster, while those oscillators belonging to different clusters remain asynchronous. Such synchronization may collapse for all clusters when the dynamics of only one oscillator is altered properly. The synchronous state may return back after a short period of transient process. This is determined by the strength of the oscillator altered. Its application in the communication of one-to-several is suggested.

  20. Comparative Toxicology of Libby Amphibole and Naturally Occurring Asbestos

    Science.gov (United States)

    Summary sentence: Comparative toxicology of Libby amphibole (LA) and site-specific naturally occurring asbestos (NOA) provides new insights on physical properties influencing health effects and mechanisms of asbestos-induced inflammation, fibrosis, and tumorigenesis.Introduction/...

  1. Comparative Toxicology of Libby Amphibole and Naturally Occurring Asbestos

    Science.gov (United States)

    Summary sentence: Comparative toxicology of Libby amphibole (LA) and site-specific naturally occurring asbestos (NOA) provides new insights on physical properties influencing health effects and mechanisms of asbestos-induced inflammation, fibrosis, and tumorigenesis.Introduction/...

  2. Protein sequences clustering of herpes virus by using Tribe Markov clustering (Tribe-MCL)

    Science.gov (United States)

    Bustamam, A.; Siswantining, T.; Febriyani, N. L.; Novitasari, I. D.; Cahyaningrum, R. D.

    2017-07-01

    The herpes virus can be found anywhere and one of the important characteristics is its ability to cause acute and chronic infection at certain times so as a result of the infection allows severe complications occurred. The herpes virus is composed of DNA containing protein and wrapped by glycoproteins. In this work, the Herpes viruses family is classified and analyzed by clustering their protein-sequence using Tribe Markov Clustering (Tribe-MCL) algorithm. Tribe-MCL is an efficient clustering method based on the theory of Markov chains, to classify protein families from protein sequences using pre-computed sequence similarity information. We implement the Tribe-MCL algorithm using an open source program of R. We select 24 protein sequences of Herpes virus obtained from NCBI database. The dataset consists of three types of glycoprotein B, F, and H. Each type has eight herpes virus that infected humans. Based on our simulation using different inflation factor r=1.5, 2, 3 we find a various number of the clusters results. The greater the inflation factor the greater the number of their clusters. Each protein will grouped together in the same type of protein.

  3. Hipax Cluster PACS Server

    Directory of Open Access Journals (Sweden)

    Ramin Payrovi

    2007-08-01

    Full Text Available Best Performace: With our Hipax Cluster PACS Server solution we are introducing the parallel computing concept as an extremely fast software system to the PACS world. In contrast to the common PACS servers, the Hipax Cluster PACS software is not only restricted to one or two computers, but can be used on a couple of servers controlling each other."nThus, the same services can be run simultaneously on different computers. The scalable system can also be expanded subsequently without lost of per-formance by adding further processors or Hipax server units, for example, if new clients or modalities are to be connected."nMaximum Failure Security: The Cluster Server concept offers high failure security. If one of the server PCs breaks down, the services can be assumed by another Hipax server unit, temporarily. If the overload of one of the server PCs is imminent, the services will be carried out by another Hipax unit (load balancing. To increase the security, e.g. against fire, the single Hipax servers can also be located separately. This concept offers maximum security, flexibility, performance, redundancy and scalability."nThe Hipax Cluster PACS Server is easy to be administrated using a web interface. In the case of a system failure (e.g. overloading, breakdown of a server PC the system administrator receives a mes-sage via Email and is so enabled to solve the problem."nFeatures"n• Based on SQL database"n• Different services running on separate PCs"n• The Hipax Server unis are coordinated and able to control each other"n• Exponentiates the power of a cluster server to the whole PACS (more processors"n• Scalable to the demands"n• Maximum performance"n• Load balancing for optimum efficiency"n• Maximum failure security because of expo-nentiated redundancy"n• Warning Email automatically sent to the system administrator in the case of failure"n• Web interface for system configuration"n• Maintenance without shut down the system

  4. Clusters of ancestrally related genes that show paralogy in whole or in part are a major feature of the genomes of humans and other species.

    Directory of Open Access Journals (Sweden)

    Michael B Walker

    Full Text Available Arrangements of genes along chromosomes are a product of evolutionary processes, and we can expect that preferable arrangements will prevail over the span of evolutionary time, often being reflected in the non-random clustering of structurally and/or functionally related genes. Such non-random arrangements can arise by two distinct evolutionary processes: duplications of DNA sequences that give rise to clusters of genes sharing both sequence similarity and common sequence features and the migration together of genes related by function, but not by common descent. To provide a background for distinguishing between the two, which is important for future efforts to unravel the evolutionary processes involved, we here provide a description of the extent to which ancestrally related genes are found in proximity.Towards this purpose, we combined information from five genomic datasets, InterPro, SCOP, PANTHER, Ensembl protein families, and Ensembl gene paralogs. The results are provided in publicly available datasets (http://cgd.jax.org/datasets/clustering/paraclustering.shtml describing the extent to which ancestrally related genes are in proximity beyond what is expected by chance (i.e. form paraclusters in the human and nine other vertebrate genomes, as well as the D. melanogaster, C. elegans, A. thaliana, and S. cerevisiae genomes. With the exception of Saccharomyces, paraclusters are a common feature of the genomes we examined. In the human genome they are estimated to include at least 22% of all protein coding genes. Paraclusters are far more prevalent among some gene families than others, are highly species or clade specific and can evolve rapidly, sometimes in response to environmental cues. Altogether, they account for a large portion of the functional clustering previously reported in several genomes.

  5. Stellar Snowflake Cluster

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 Stellar Snowflake Cluster Combined Image [figure removed for brevity, see original site] Figure 2 Infrared Array CameraFigure 3 Multiband Imaging Photometer Newborn stars, hidden behind thick dust, are revealed in this image of a section of the Christmas Tree cluster from NASA's Spitzer Space Telescope, created in joint effort between Spitzer's infrared array camera and multiband imaging photometer instruments. The newly revealed infant stars appear as pink and red specks toward the center of the combined image (fig. 1). The stars appear to have formed in regularly spaced intervals along linear structures in a configuration that resembles the spokes of a wheel or the pattern of a snowflake. Hence, astronomers have nicknamed this the 'Snowflake' cluster. Star-forming clouds like this one are dynamic and evolving structures. Since the stars trace the straight line pattern of spokes of a wheel, scientists believe that these are newborn stars, or 'protostars.' At a mere 100,000 years old, these infant structures have yet to 'crawl' away from their location of birth. Over time, the natural drifting motions of each star will break this order, and the snowflake design will be no more. While most of the visible-light stars that give the Christmas Tree cluster its name and triangular shape do not shine brightly in Spitzer's infrared eyes, all of the stars forming from this dusty cloud are considered part of the cluster. Like a dusty cosmic finger pointing up to the newborn clusters, Spitzer also illuminates the optically dark and dense Cone nebula, the tip of which can be seen towards the bottom left corner of each image. This combined image shows the presence of organic molecules mixed with dust as wisps of green, which have been illuminated by nearby star formation. The larger yellowish dots neighboring the baby red stars in the Snowflake Cluster are massive stellar infants forming from the same cloud. The blue dots

  6. Cycles and Clustering in Multiplex Networks

    CERN Document Server

    Baxter, Gareth J; Dorogovtsev, Sergey N; Mendes, José F F

    2016-01-01

    In multiplex networks, cycles cannot be characterized only by their length, as edges may occur in different layers in different combinations. We define a classification of cycles by the number of edges in each layer and the number of switches between layers. We calculate the expected number of cycles of each type in the configuration model of a large sparse multiplex network. Our method accounts for the full degree distribution including correlations between degrees in different layers. In particular, we obtain the numbers of cycles of length 3 of all possible types. Using these, we give a complete set of clustering coefficients and their expected values. We show that correlations between the degrees of a vertex in different layers strongly affect the number of cycles of a given type, and the number of switches between layers. Both increase with assortative correlations and are strongly decreased by disassortative correlations. The effect of correlations on clustering coefficients is equally pronounced.

  7. Sleep and chronobiology in cluster headache

    DEFF Research Database (Denmark)

    Barloese, M; Lund, N.; Petersen, A

    2015-01-01

    BACKGROUND AND AIM: Cluster headache (CH) is the headache disorder with the strongest chronobiological traits. The severe attacks of pain occur with diurnal and annual rhythmicity but the precise rhythm and involvement of potential zeitgebers is unknown. Patients complain of poor sleep quality yet...... this has never been studied. We investigated triggers, rhythms, sleep quality and chronotypes in CH. METHODS: Patients and controls completed questionnaires and structured interviews composed of new and previously validated parts including the Pittsburgh Sleep Quality Index (PSQI) and Morningness......-Eveningness Questionnaire (MEQ). Patients were characterized by a CH index, a unified measure of headache burden. RESULTS: A total of 275 CH patients and 145 matched controls were included. The most common trigger was sleep (80%) and a relationship between clusters and daylight was identified. Of the patients, 82...

  8. Cell Division, Differentiation and Dynamic Clustering

    CERN Document Server

    Kaneko, K; Kaneko, Kunihiko; Yomo, Tetsuya

    1993-01-01

    A novel mechanism for cell differentiation is proposed, based on the dynamic clustering in a globally coupled chaotic system. A simple model with metabolic reaction, active transport of chemicals from media, and cell division is found to show three successive stages with the growth of the number of cells; coherent growth, dynamic clustering, and fixed cell differentiation. At the last stage, disparity in activities, germ line segregation, somatic cell differentiation, and homeochaotic stability against external perturbation are found. Our results, in consistency with the experiments of the preceding paper, imply that cell differentiation can occur without a spatial pattern. From dynamical systems viewpoint, the new concept of ``open chaos" is proposed, as a novel and general scenario for systems with growing numbers of elements, also seen in economics and sociology.A

  9. Equivalent damage validation by variable cluster analysis

    Science.gov (United States)

    Drago, Carlo; Ferlito, Rachele; Zucconi, Maria

    2016-06-01

    The main aim of this work is to perform a clustering analysis on the damage relieved in the old center of L'Aquila after the earthquake occurred on April 6, 2009 and to validate an Indicator of Equivalent Damage ED that summarizes the information reported on the AeDES card regarding the level of damage and their extension on the surface of the buildings. In particular we used a sample of 13442 masonry buildings located in an area characterized by a Macroseismic Intensity equal to 8 [1]. The aim is to ensure the coherence between the clusters and its hierarchy identified in the data of damage detected and in the data of the ED elaborated.

  10. White Dwarfs in Globular Clusters

    CERN Document Server

    Möhler, S

    2008-01-01

    We review empirical and theoretical findings concerning white dwarfs in Galactic globular clusters. Since their detection is a critical issue we describe in detail the various efforts to find white dwarfs in globular clusters. We then outline the advantages of using cluster white dwarfs to investigate the formation and evolution of white dwarfs and concentrate on evolutionary channels that appear to be unique to globular clusters. We also discuss the usefulness of globular cluster white dwarfs to provide independent information on the distances and ages of globular clusters, information that is very important far beyond the immediate field of white dwarf research. Finally, we mention possible future avenues concerning globular cluster white dwarfs, like the study of strange quark matter or plasma neutrinos.

  11. Optical radii of galaxy clusters

    CERN Document Server

    Girardi, M; Giuricin, G; Mardirossian, F; Mezzetti, M; Girardi, M; Biviano, A; Giuricin, G; Mardirossian, F; Mezzetti, M

    1994-01-01

    We analyze the density profiles and virial radii for a sample of 90 nearby clusters, using galaxies with available redshifts and positions. Each cluster has at least 20 redshifts measured within an Abell radius, and all the results come from galaxy sets of at least 20 members. Most of the density profiles of our clusters are well fitted by hydrostatic-isothermal-like profiles. The slopes we find for many cluster density profiles are consistent with the hypothesis that the galaxies are in equilibrium with the binding cluster potential. The virial radii correlate with the core radii at a very high significance level. The observed relationship between the two size estimates is in agreement with the theoretical one computed by using the median values of the density profile parameters fitted on our clusters. After correcting for incompleteness in our cluster sample, we provide the universal distributions functions of core and virial radii (obtained within half an Abell radius).

  12. Clustering Methodologies for Software Engineering

    Directory of Open Access Journals (Sweden)

    Mark Shtern

    2012-01-01

    Full Text Available The size and complexity of industrial strength software systems are constantly increasing. This means that the task of managing a large software project is becoming even more challenging, especially in light of high turnover of experienced personnel. Software clustering approaches can help with the task of understanding large, complex software systems by automatically decomposing them into smaller, easier-to-manage subsystems. The main objective of this paper is to identify important research directions in the area of software clustering that require further attention in order to develop more effective and efficient clustering methodologies for software engineering. To that end, we first present the state of the art in software clustering research. We discuss the clustering methods that have received the most attention from the research community and outline their strengths and weaknesses. Our paper describes each phase of a clustering algorithm separately. We also present the most important approaches for evaluating the effectiveness of software clustering.

  13. Convex Clustering: An Attractive Alternative to Hierarchical Clustering

    Science.gov (United States)

    Chen, Gary K.; Chi, Eric C.; Ranola, John Michael O.; Lange, Kenneth

    2015-01-01

    The primary goal in cluster analysis is to discover natural groupings of objects. The field of cluster analysis is crowded with diverse methods that make special assumptions about data and address different scientific aims. Despite its shortcomings in accuracy, hierarchical clustering is the dominant clustering method in bioinformatics. Biologists find the trees constructed by hierarchical clustering visually appealing and in tune with their evolutionary perspective. Hierarchical clustering operates on multiple scales simultaneously. This is essential, for instance, in transcriptome data, where one may be interested in making qualitative inferences about how lower-order relationships like gene modules lead to higher-order relationships like pathways or biological processes. The recently developed method of convex clustering preserves the visual appeal of hierarchical clustering while ameliorating its propensity to make false inferences in the presence of outliers and noise. The solution paths generated by convex clustering reveal relationships between clusters that are hidden by static methods such as k-means clustering. The current paper derives and tests a novel proximal distance algorithm for minimizing the objective function of convex clustering. The algorithm separates parameters, accommodates missing data, and supports prior information on relationships. Our program CONVEXCLUSTER incorporating the algorithm is implemented on ATI and nVidia graphics processing units (GPUs) for maximal speed. Several biological examples illustrate the strengths of convex clustering and the ability of the proximal distance algorithm to handle high-dimensional problems. CONVEXCLUSTER can be freely downloaded from the UCLA Human Genetics web site at http://www.genetics.ucla.edu/software/ PMID:25965340

  14. Interrupted Binary Mass Transfer in Star Clusters

    Science.gov (United States)

    Leigh, Nathan W. C.; Geller, Aaron M.; Toonen, Silvia

    2016-02-01

    Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲ {10}4 {M}⊙ ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect \\ll 1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ˜2.

  15. Web Fuzzy Clustering and a Case Study

    Institute of Scientific and Technical Information of China (English)

    LIU Mao-fu; HE Jing; HE Yan-xiang; HU Hui-jun

    2004-01-01

    We combine the web usage mining and fuzzy clustering and give the concept of web fuzzy clustering, and then put forward the web fuzzy clustering processing model which is discussed in detail. Web fuzzy clustering can be used in the web users clustering and web pages clustering. In the end, a case study is given and the result has proved the feasibility of using web fuzzy clustering in web pages clustering.

  16. A Density-Dependent Switch Drives Stochastic Clustering and Polarization of Signaling Molecules

    Science.gov (United States)

    Jilkine, Alexandra; Angenent, Sigurd B.; Wu, Lani F.; Altschuler, Steven J.

    2011-01-01

    Positive feedback plays a key role in the ability of signaling molecules to form highly localized clusters in the membrane or cytosol of cells. Such clustering can occur in the absence of localizing mechanisms such as pre-existing spatial cues, diffusional barriers, or molecular cross-linking. What prevents positive feedback from amplifying inevitable biological noise when an un-clustered “off” state is desired? And, what limits the spread of clusters when an “on” state is desired? Here, we show that a minimal positive feedback circuit provides the general principle for both suppressing and amplifying noise: below a critical density of signaling molecules, clustering switches off; above this threshold, highly localized clusters are recurrently generated. Clustering occurs only in the stochastic regime, suggesting that finite sizes of molecular populations cannot be ignored in signal transduction networks. The emergence of a dominant cluster for finite numbers of molecules is partly a phenomenon of random sampling, analogous to the fixation or loss of neutral mutations in finite populations. We refer to our model as the “neutral drift polarity model.” Regulating the density of signaling molecules provides a simple mechanism for a positive feedback circuit to robustly switch between clustered and un-clustered states. The intrinsic ability of positive feedback both to create and suppress clustering is a general mechanism that could operate within diverse biological networks to create dynamic spatial organization. PMID:22102805

  17. A density-dependent switch drives stochastic clustering and polarization of signaling molecules.

    Directory of Open Access Journals (Sweden)

    Alexandra Jilkine

    2011-11-01

    Full Text Available Positive feedback plays a key role in the ability of signaling molecules to form highly localized clusters in the membrane or cytosol of cells. Such clustering can occur in the absence of localizing mechanisms such as pre-existing spatial cues, diffusional barriers, or molecular cross-linking. What prevents positive feedback from amplifying inevitable biological noise when an un-clustered "off" state is desired? And, what limits the spread of clusters when an "on" state is desired? Here, we show that a minimal positive feedback circuit provides the general principle for both suppressing and amplifying noise: below a critical density of signaling molecules, clustering switches off; above this threshold, highly localized clusters are recurrently generated. Clustering occurs only in the stochastic regime, suggesting that finite sizes of molecular populations cannot be ignored in signal transduction networks. The emergence of a dominant cluster for finite numbers of molecules is partly a phenomenon of random sampling, analogous to the fixation or loss of neutral mutations in finite populations. We refer to our model as the "neutral drift polarity model." Regulating the density of signaling molecules provides a simple mechanism for a positive feedback circuit to robustly switch between clustered and un-clustered states. The intrinsic ability of positive feedback both to create and suppress clustering is a general mechanism that could operate within diverse biological networks to create dynamic spatial organization.

  18. Interpersonal Callousness and Co-Occurring Anxiety: Developmental Validity of an Adolescent Taxonomy

    Science.gov (United States)

    2016-01-01

    Growing evidence suggests heterogeneity within interpersonal-callous (IC) youth based on co-occurring anxiety. The developmental validity of this proposed taxonomy remains unclear however, as most previous research is cross-sectional and/or limited to adolescence. We aimed to identify low-anxiety (IC/ANX−) and high-anxiety (IC/ANX+) IC variants, and compare these groups on (a) early risk exposures, (b) psychiatric symptoms from midchildhood to early adolescence, and (c) school-based functioning. Using the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective epidemiological birth cohort, model-based cluster analysis was performed on children with complete age-13 IC and anxiety scores (n = 6,791). Analysis of variance was used to compare resulting clusters on (a) prenatal and postnatal family adversity and maternal psychopathology, and harsh parenting; (b) developmental differences in attention-deficit/hyperactivity disorder (ADHD), conduct disorder (CD), oppositional defiant disorder (ODD), emotional difficulties, and low pro-social behavior at 7, 10, and 13 years; and (c) teacher-reported discipline problems, along with standardized test performance. We identified a 4-cluster solution: “typical,” “low,” “IC/ANX−”, and “IC/ANX+.” IC/ANX+ youth showed the highest prenatal and postnatal levels of family adversity and maternal psychopathology, highest levels of ADHD, CD, ODD, and emotional difficulties, greatest discipline problems, and lowest national test scores (all p < .001). IC/ANX+ also showed a distinct pattern of increasing psychopathology from age 7 to 13 years. Adolescent IC subtypes were successfully validated in ALSPAC across multiple raters using prenatal and early postnatal risk, repeated measures of psychopathology, and school-based outcomes. Greater prenatal environmental risk among IC/ANX+ youth suggests an important target for early intervention. PMID:27977232

  19. Clustering of agricultural enterprises

    Directory of Open Access Journals (Sweden)

    Michaela Beranová

    2013-01-01

    Full Text Available Agricultural business is a very specific branch which is characterized by very low financial performance while this characteristic is given mainly by external factors as market pricing of agricultural commodities on one side, and production costs of agricultural commodities on the other side. This way, agricultural enterprises recognize negative values of gross margin in the Profit and Loss Statement but positive value of operating profit after even there are items of costs which are deducted. These results are derived from agricultural production subsidies which are recognized as income in the P/L Statement. In connection with this fact, the government subsidies are a substantial component of financial performance of agricultural enterprises.Primary research proceeded on the statistical sample of one hundred agricultural companies, has shown that also other specifics influencing financial performance of these businesses exist here. In order to determine the influences, the cluster analysis has been applied at using more than 10 variables. This approach has led to construction of clusters (groups of agricultural business entities with different characteristics of the group. The objective of this paper is to identify the main determinants of financial performance of agricultural enterprises and to determine their influences under different economic characteristics of these business entities. For this purpose, the regression analysis has been subsequently applied on the groups of companies coming out from the cluster analysis. Besides the operating profit which is the main driving force of financial performance measured with the economic value added (EVA in agricultural enterprises, also capital structure and cost of capital have been observed as very strong influences on financial performance but these factors have different directions of their influence on the economic value added under different financial characteristics of agricultural

  20. Introduction to Clustering Algorithms and Applications

    OpenAIRE

    Yang, Sibei; Tao, Liangde; Gong, Bingchen

    2014-01-01

    Data clustering is the process of identifying natural groupings or clusters within multidimensional data based on some similarity measure. Clustering is a fundamental process in many different disciplines. Hence, researchers from different fields are actively working on the clustering problem. This paper provides an overview of the different representative clustering methods. In addition, application of clustering in different field is briefly introduced.

  1. Skin picking disorder with co-occurring body dysmorphic disorder.

    Science.gov (United States)

    Grant, Jon E; Redden, Sarah A; Leppink, Eric W; Odlaug, Brian L

    2015-09-01

    There is clinical overlap between skin picking disorder (SPD) and body dysmorphic disorder (BDD), but little research has examined clinical and cognitive correlates of the two disorders when they co-occur. Of 55 participants with SPD recruited for a neurocognitive study and two pharmacological studies, 16 (29.1%) had co-occurring BDD. SPD participants with and without BDD were compared to each other and to 40 healthy volunteers on measures of symptom severity, social functioning, and cognitive assessments using the Stop-signal task (assessing response impulsivity) and the Intra-dimensional/Extra-dimensional Set Shift task (assessing cognitive flexibility). Individuals with SPD and BDD exhibited significantly worse picking, significantly worse overall psychosocial functioning, and significantly greater dysfunction on aspects of cognitive flexibility. These results indicate that when SPD co-occurs with BDD unique clinical and cognitive aspects of SPD may be more pronounced. Future work should explore possible subgroups in SPD and whether these predict different treatment outcomes.

  2. Endometrial carcinoma occuring from polycystic ovary disease : A case report

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Su Ok; Jeon, Woo Ki [Inje Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-12-01

    Endometrial carcinoma usually occurs in postmenopausal women ; less than 5% occurs in women under the age of 40. Up to one quarter of endometrial carcinoma patients below this age have PCO(polycystic ovary disease, Stein-Leventhal syndrome). The increased incidence of endometrial carcinoma in patients with PCO is related to chronic estrogenic stimulation. We report MR imaging in one case of endometrial carcinoma occuring in a 23 year old woman with PCO and had complained of hypermenorrhea for about three years. On T2-weighted MR image the endometrial cavity was seen to be distended with protruded endometrial masses of intermediate signal intensity, and the junctional zone was disrupted beneath the masses. Both ovaries were best seen on T2-weighted MR imaging and showed multiple small peripheral cysts and low signal-intensity central stroma.

  3. Hadoop cluster deployment

    CERN Document Server

    Zburivsky, Danil

    2013-01-01

    This book is a step-by-step tutorial filled with practical examples which will show you how to build and manage a Hadoop cluster along with its intricacies.This book is ideal for database administrators, data engineers, and system administrators, and it will act as an invaluable reference if you are planning to use the Hadoop platform in your organization. It is expected that you have basic Linux skills since all the examples in this book use this operating system. It is also useful if you have access to test hardware or virtual machines to be able to follow the examples in the book.

  4. Sketching Star Clusters

    Science.gov (United States)

    Perez, Jeremy

    The next time you plan a quiet evening under a salted sky, with hopes of bathing your eyes in the ancient light of a majestic star cluster, be sure that your sketching kit comes with you! A casual glance at these celestial marvels will not give you a decent appreciation for an object whose history and character are as unique as the fingerprints you should be pressing into the side of your trusty pencil. I can think of no better way to connect with these stellar ballets, to understand their intricacies, and to recall your view later than to spend time sketching the soft glow or blazing pinpricks you see through the eyepiece.

  5. Complete mtDNA sequences of two millipedes suggest a new model for mitochondrial gene rearrangements: Duplication and non-random loss

    Energy Technology Data Exchange (ETDEWEB)

    Lavrov, Dennis V.; Boore, Jeffrey L.; Brown, Wesley M.

    2001-11-08

    We determined the complete mtDNA sequences of the millipedes Narceus annularus and Thyropygus sp. (Arthropoda: Diplopoda) and identified in both genomes all 37 genes typical for metazoan mtDNA. The arrangement of these genes is identical in the two millipedes, but differs from that inferred to be ancestral for arthropods by the location of four genes/gene clusters. This novel gene arrangement is unusual for animal mtDNA, in that genes with opposite transcriptional polarities are clustered in the genome and the two clusters are separated by two non-coding regions. The only exception to this pattern is the gene for cysteine tRNA, which is located in the part of the genome that otherwise contains all genes with the opposite transcriptional polarity. We suggest that a mechanism involving complete mtDNA duplication followed by the loss of genes, predetermined by their transcriptional polarity and location in the genome, could generate this gene arrangement from the one ancestral for arthropods. The proposed mechanism has important implications for phylogenetic inferences that are drawn on the basis of gene arrangement comparisons.

  6. Fragmentation energetics of clusters relevant to atmospheric new particle formation.

    Science.gov (United States)

    Bzdek, Bryan R; DePalma, Joseph W; Ridge, Douglas P; Laskin, Julia; Johnston, Murray V

    2013-02-27

    The exact mechanisms by which small clusters form and grow in the atmosphere are poorly understood, but this process may significantly impact cloud condensation nuclei number concentrations and global climate. Sulfuric acid is the key chemical component to new particle formation (NPF), but basic species such as ammonia are also important. Few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer equipped with surface-induced dissociation to investigate time- and collision-energy-resolved fragmentation of positively charged ammonium bisulfate clusters. Critical energies for dissociation are obtained from Rice-Ramsperger-Kassel-Marcus/quasi-equilibrium theory modeling of the experimental data and are compared to quantum chemical calculations of the thermodynamics of cluster dissociation. Fragmentation of ammonium bisulfate clusters occurs by two pathways: (1) a two-step pathway whereby the cluster sequentially loses ammonia followed by sulfuric acid and (2) a one-step pathway whereby the cluster loses an ammonium bisulfate molecule. Experimental critical energies for loss of an ammonia molecule and loss of an ammonium bisulfate molecule are higher than the thermodynamic values. If cluster growth is considered the reverse of cluster fragmentation, these results require the presence of an activation barrier to describe the incorporation of ammonia into small acidic clusters and suggest that kinetically (i.e., diffusion) limited growth should not be assumed. An important corollary is that models of atmospheric NPF should be revised to consider activation barriers to individual chemical steps along the growth pathway.

  7. Fragmentation Energetics of Clusters Relevant to Atmospheric New Particle Formation

    Energy Technology Data Exchange (ETDEWEB)

    Bzdek, Bryan R.; Depalma, Joseph W.; Ridge, Douglas P.; Laskin, Julia; Johnston, Murray V.

    2013-02-27

    The exact mechanisms by which small clusters form and grow in the atmosphere are poorly understood, but this process may significantly impact cloud condensation nuclei number concentrations and global climate. Sulfuric acid is the key chemical component to new particle formation, but basic species such as ammonia are also important. However, few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer equipped with surface-induced dissociation (FTICR-SID) to investigate time- and collision energy-resolved fragmentation of positively charged ammonium bisulfate clusters. Critical energies for dissociation are obtained from Rice-Ramsperger-Kassel-Marcus/Quasi-Equilibrium Theory (RRKM/QET) modeling of the experimental data and are compared to quantum chemical calculations of the thermodynamics of cluster dissociation. Fragmentation of ammonium bisulfate clusters occurs by two pathways: 1) a two-step pathway whereby the cluster sequentially loses ammonia followed by sulfuric acid and 2) a one-step pathway whereby the cluster loses an ammonium bisulfate molecule. Experimental critical energies for loss of an ammonia molecule and loss of an ammonium bisulfate molecule are higher than the thermodynamic values. If cluster growth is considered the reverse of cluster fragmentation, these results require the presence of an activation barrier to describe the incorporation of ammonia into small acidic clusters and suggest that kinetically (i.e. diffusion) limited growth should not be assumed. An important corollary is that models of atmospheric NPF should be revised to consider activation barriers to individual chemical steps along the growth pathway.

  8. Mining Bacterial Genomes for Secondary Metabolite Gene Clusters.

    Science.gov (United States)

    Adamek, Martina; Spohn, Marius; Stegmann, Evi; Ziemert, Nadine

    2017-01-01

    With the emergence of bacterial resistance against frequently used antibiotics, novel antibacterial compounds are urgently needed. Traditional bioactivity-guided drug discovery strategies involve laborious screening efforts and display high rediscovery rates. With the progress in next generation sequencing methods and the knowledge that the majority of antibiotics in clinical use are produced as secondary metabolites by bacteria, mining bacterial genomes for secondary metabolites with antimicrobial activity is a promising approach, which can guide a more time and cost-effective identification of novel compounds. However, what sounds easy to accomplish, comes with several challenges. To date, several tools for the prediction of secondary metabolite gene clusters are available, some of which are based on the detection of signature genes, while others are searching for specific patterns in gene content or regulation.Apart from the mere identification of gene clusters, several other factors such as determining cluster boundaries and assessing the novelty of the detected cluster are important. For this purpose, comparison of the predicted secondary metabolite genes with different cluster and compound databases is necessary. Furthermore, it is advisable to classify detected clusters into gene cluster families. So far, there is no standardized procedure for genome mining; however, different approaches to overcome all of these challenges exist and are addressed in this chapter. We give practical guidance on the workflow for secondary metabolite gene cluster identification, which includes the determination of gene cluster boundaries, addresses problems occurring with the use of draft genomes, and gives an outlook on the different methods for gene cluster classification. Based on comprehensible examples a protocol is set, which should enable the readers to mine their own genome data for interesting secondary metabolites.

  9. Convex Decomposition Based Cluster Labeling Method for Support Vector Clustering

    Institute of Scientific and Technical Information of China (English)

    Yuan Ping; Ying-Jie Tian; Ya-Jian Zhou; Yi-Xian Yang

    2012-01-01

    Support vector clustering (SVC) is an important boundary-based clustering algorithm in multiple applications for its capability of handling arbitrary cluster shapes. However,SVC's popularity is degraded by its highly intensive time complexity and poor label performance.To overcome such problems,we present a novel efficient and robust convex decomposition based cluster labeling (CDCL) method based on the topological property of dataset.The CDCL decomposes the implicit cluster into convex hulls and each one is comprised by a subset of support vectors (SVs).According to a robust algorithm applied in the nearest neighboring convex hulls,the adjacency matrix of convex hulls is built up for finding the connected components; and the remaining data points would be assigned the label of the nearest convex hull appropriately.The approach's validation is guaranteed by geometric proofs.Time complexity analysis and comparative experiments suggest that CDCL improves both the efficiency and clustering quality significantly.

  10. Why Does Bureaucratic Corruption Occur in the EU?

    DEFF Research Database (Denmark)

    Brandt, Urs Steiner; Svendsen, Gert Tinggaard

    2013-01-01

    Why does bureaucratic corruption occur in the EU system? Several examples suggest that bureaucratic corruption exists and that the Commission’s anti-fraud agency, OLAF, is not a fully independent authority. We thus develop a novel interpretation of the principalsupervisor-agent model to cope...... with non-independent anti-fraud units. This model shows that corruption is likely to occur when the expected value to the client from bribing the agent is larger than the expected value to the principal of truth-telling by the supervisor. Overall, this analysis points to the risks of flawed incentives...

  11. Factors affecting the depth of burns occurring in medical institutions.

    Science.gov (United States)

    Cho, Young Soon; Choi, Young Hwan; Yoon, Cheonjae; You, Je Sung

    2015-05-01

    Most cases of burns occurring in medical institutions are associated with activities involving heat. It is very difficult to detect these burns. To date, there are few reports on burns occurring in medical institutions. The purpose of this paper was to analyze the etiology of burns occurring in medical institutions and to elucidate the factors affecting burn depth. We conducted a retrospective analysis of the medical records of patients who visited our center from April 2008 to February 2013. This study enrolled all patients with burns occurring in the medical institution during or related to treatment. We excluded burn patients whose burns were not related to treatment (for example, we excluded patients with scalding burns that occurred in the hospital cafeteria and pediatric patients with hot water burns from the water purifier). However, patients with burns that occurred in the recovery room after general anesthesia were included. A total of 115 patients were enrolled in this study. The average patient age was 41.5 years, with more women than men (M:F=31:84). There were 29 cases (25.3%) of superficial burns (first-degree and superficial second-degree) and 86 cases (74.7%) of deep burns (deep second-degree and third-degree). Hot packs were the most common cause of burns (27 cases, 23.5%), followed by laser therapy, heating pads, and grounding pads, accounting for 15 cases each. There were 89 cases (77.4%) of contact burns and 26 cases (22.6%) of non-contact burns. The most common site of burns was the lower extremities (41 cases, 35.7%). The burn site and contact burns were both factors affecting burn depth. The rate of deep burns was higher in patients with contact burns than in those with non-contact burns (odds ratio 4.26) and was associated with lower body burns (odds ratio 2.85). In burns occurring in medical institutions, there is a high probability of a deep burn if it is a contact burn or occurs in the lower body. Therefore, safety guidelines are needed

  12. Can spontaneous symmetry breaking occur in potential with one minimum?

    CERN Document Server

    Acus, A

    2000-01-01

    Spontaneous symmetry breaking occurs when the symmetry that a physical system possesses, is not preserved for the ground state of the system. Although the procedure of symmetry breaking is quite clear from the mathematical point of view, the physical interpretation of the phenomenon is worth to be better understood. In this note we present a simple and instructive example of the symmetry breaking in a mechanical system. It demonstrates that the spontaneous symmetry breaking can occur for the spatially extended solutions in a potential characterised by a single minimum.

  13. Skin picking disorder with co-occurring body dysmorphic disorder

    DEFF Research Database (Denmark)

    Grant, Jon E; Redden, Sarah A; Leppink, Eric W

    2015-01-01

    There is clinical overlap between skin picking disorder (SPD) and body dysmorphic disorder (BDD), but little research has examined clinical and cognitive correlates of the two disorders when they co-occur. Of 55 participants with SPD recruited for a neurocognitive study and two pharmacological...... studies, 16 (29.1%) had co-occurring BDD. SPD participants with and without BDD were compared to each other and to 40 healthy volunteers on measures of symptom severity, social functioning, and cognitive assessments using the Stop-signal task (assessing response impulsivity) and the Intra...

  14. Binaries in Globular Clusters Multiple Populations

    Science.gov (United States)

    Lucatello, Sara; Sollima, Antonio; Gratton, Raffaele; D'Orazi, Valentina; Vesperini, Enrico; Carretta, Eugenio; Bragaglia, Angela

    2015-08-01

    In spite of considerable theoretical and obsservational effort, the series of events that leads to the formation of Globular Clusters and their multiple populations is still unclear.One of the key matters is where the so-called second generation of stars form and its distribution at the time of its birth with respect to the first generation. Some of the latest modeling has suggested that second generation should form in a compact subsystem concentrated in the inner regions of the primordial, first generation cluster. In this scenario, loss of a large fraction of the cluster mass is expected, mostly comprised of first generation stars. This would account for the mass budget issue (one of the main problems in the self-enrichment scenario) and would imply a considerable contribution of the clusters to the formation of the Galactic Halo.Testing this prediction is hence of great importance, but not so immediate. Long-term, dynamical evolution of multiple-population clusters could blur considerably the signature of the initial different concentrations, leaving at present time some memory in the very central part (Vesperini et al. 2013), which, because of its high density, is generally not accessible to the multi-object high resolution spectrographs that yield the spectra that allow the chemical composition measurements necessary to tag the different populations.An alternative approach to test the prediction of the initial segregation of the second generations is that of determining their binary fractions. In fact, until the two populations are completely mixed, second generation stars will evolve in a denser environment where disruption will occur more rapidly, leading to a smaller binary incidence in such population (Vesperini et al 2011).I will present the results of our long-term radial velocity monitoring of 10 Galactic Globular clusters, discuss the derived binary fractions in the two populations and address the implications of our findings on our understanding of

  15. Cluster beam investigation with MCPs

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Esperanza; Bonaventura, Daniel; Grieser, Silke; Hergemoeller, Ann-Katrin; Taeschner, Alexander; Khoukaz, Alfons [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster, 48149 Muenster (Germany)

    2014-07-01

    High intensity cluster-jet beams produced in Laval nozzles represent a very attractive and extremely interesting tool for studies at storage ring experiments, such as PANDA, or for laser-induced particle acceleration. Since the cluster properties vary with increasing number of constituents, it is essential to perform systematic measurements on the target thickness and especially on the cluster masses. For this purpose a monitoring system based on Micro Channel Plates (MCPs) combined with a phosphor screen has been developed and installed at the beam dump of the PANDA prototype cluster-jet target in Muenster. It could be shown that this MCP system allows for a direct observation of an ionised cluster beam. In addition, with this setup the possibility to visualise the vertex zone at the ANKE cluster-jet target at COSY was succesfully demonstrated, where a proton beam with a momentum of 2.09 GeV/c interacted with a hydrogen cluster-jet beam. Furthermore, cluster mass investigations can be performed in conjunction with a retardation field. In this presentation an overview of the MCP detection system, images of the cluster-jet beam and the vertex zone as well as the results of the current cluster mass measurements are presented and discussed.

  16. Estimating the Number of Clusters via Normalized Cluster Instability

    OpenAIRE

    Haslbeck, Jonas M. B.; Wulff, Dirk U.

    2016-01-01

    We improve existing instability-based methods for the selection of the number of clusters $k$ in cluster analysis by normalizing instability. In contrast to existing instability methods which only perform well for bounded sequences of small $k$, our method performs well across the whole sequence of possible $k$. In addition, we compare for the first time model-based and model-free variants of $k$ selection via cluster instability and find that their performance is similar. We make our method ...

  17. Close encounters involving free-floating planets in star clusters

    CERN Document Server

    Wang, Long; Zheng, Xiaochen; Church, Ross P; Davies, Melvyn B

    2015-01-01

    Instabilities in planetary systems can result in the ejection of planets from their host system, resulting in free-floating planets (FFPs). If this occurs in a star cluster, the FFP may remain bound to the star cluster for some time and interact with the other cluster members until it is ejected. Here, we use $N$-body simulations to characterise close star-planet and planet-planet encounters and the dynamical fate of the FFP population in star clusters containing $500-2000$ single or binary star members. We find that FFPs ejected from their planetary system at low velocities typically leave the star cluster 40% earlier than their host stars, and experience tens of close ($<1000$ AU) encounters with other stars and planets before they escape. The fraction of FFPs that experiences a close encounter depends on both the stellar density and the initial velocity distribution of the FFPs. Approximately half of the close encounters occur within the first 30 Myr, and only 10% occur after 100 Myr. The periastron vel...

  18. Effect of post-stroke sensory disorders on the recovery processes of motor function and activity of daily living A non-randomized synchroniesl controlled trial

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    BACKGROUND:In the rehabilitation of stroke patients,clinicians usually concentrate on motor problems,such as spasm of limbs and restriction of joint motion,while sensory and perceptive problems are almost always neglected,although they are just as important.One such area is the sensory disorder. OBJECTIVE:To evaluate the motor function and activities of daily living in stroke patients with and without sensory disorders after treatment of integrated western and Chinese medicine.DESIGN:A non-randomized synchronically controlled trial.SETTING:First Affiliated Hospital of Tianjin College of Traditional Chinese Medicine.PARTICIPANTS:Totally 500 stroke inpatients were selected from the Department of Acupuncture and Massage,the First Affiliated Hospital of Tianjin College of Traditional Chinese Medicine from January 2003 to December 2004.They all had suffered from stroke in the last 4 weeks and accompanied by sensory disorder of the ipsilateral limb to different severity.The patients were all accorded with the Diagnostic and Efficacy Evaluative Standards for Stroke (in trial)set by the Encephalopathy Emergency Assistant Group,the State Administration of Traditional Chinese Medicine in 1995,and they were diagnosed by imaging examination.The patients were stratified into sensory disorder group (n =220) and normal sense group (n=280).Informed consent for the detected items and therapeutic program was obtained from the relatives of all the participants.The study was approved by the hospital ethical committee.METHODS:All the patients were treated with acupuncture of Xing Nao Kai Qiao for restoring consciousness and inducing resuscitation,assisted by traditional Chinese medicine and western medicine specific to corresponding symptoms.The therapeutic principles were restoring consciousness and inducing resuscitation,nourishing liver and kidney,and dredging meridian.In addition,the patients were given western medical treatments for decreasing intracranial pressure

  19. Tacrolimus versus intravenous pulse cyclophosphamide therapy in Chinese adults with steroid-resistant idiopathic minimal change nephropathy: a multicenter, open-label, nonrandomized cohort trial.

    Science.gov (United States)

    Li, Heng; Shi, Xiangdong; Shen, Hong; Li, Xiayu; Wang, Huiping; Li, Hongmei; Xu, Guangbiao; Chen, Jianghua

    2012-05-01

    The treatment of steroid-resistant minimal change nephropathy (SR-MCN) in adults remains a challenge to nephrologists. Although immunosuppressants such as cyclophosphamide (CTX), chlorambucil, and cyclosporin A have been used in these patients, their use has been limited by low remission rates and severe adverse effects. Alternative immunosuppressive treatments for SR-MCN are therefore needed. The aim of this study was to compare the efficacy of tacrolimus (TAC) with that of intravenous (IV) pulse CTX therapy in the management of SR-MCN and to assess the tolerability of those treatments. This was a nonrandomized, case-matched trial in Chinese adults with SR-MCN. Patients were self-assigned to either: (1) combination therapy with prednisone and oral TAC; or (2) combination therapy with prednisone and IV CTX. TAC was initiated at 0.05 mg/kg/d and was adjusted to maintain a trough blood level of 5 to 10 ng/mL for 1 year. CTX was initiated at 1 g/1.73 m(2) for a total dosage of 10 g/1.73 m(2) over 1 year. In both groups, oral prednisone was initiated at 0.5 mg/kg/d for 3 months but was tapered off to complete cessation by 6 months. A total of 37 patients were enrolled (21 in the TAC group; 16 in the CTX group), of whom 33 (19 in the TAC group; 14 in the CTX group) completed the study. There were no significant difference in baseline demographic characteristics between the two treatment groups (The TAC group-mean age at onset, 28.8 [11.3]; mean age at trial, 29.6 [11.0]; male, 63.16%; The CTX group-mean age at onset, 34.4 [12.7]; mean age at trial, 35.9 [12.7]; male, 57.14%). The remission rates were 57.9%, 73.7%, and 78.9% in the TAC group and 14.3%, 42.9%, and 50.0% in the CTX group after 2, 4, and 6 months, respectively. The remission rate at 2 months was significantly higher in the TAC group than in the CTX group (P therapy and the 1-year follow-up were higher in the TAC group than in the CTX group (Kaplan-Meier curve, log-rank test, P therapy and 1-year follow

  20. Brightest Cluster Galaxies and Core Gas Density in REXCESS Clusters

    CERN Document Server

    Haarsma, D B; Donahue, M; Bruch, S; Boehringer, H; Croston, J H; Pratt, G W; Voit, G M; Arnaud, M; Pierini, D

    2009-01-01

    We investigate the relationship between brightest cluster galaxies (BCGs) and their host clusters using a sample of nearby galaxy clusters from the Representative XMM-Newton Cluster Structure Survey (REXCESS). The sample was imaged with the Southern Observatory for Astrophysical Research (SOAR) in R band to investigate the mass of the old stellar population. Using a metric radius of 12h^-1 kpc, we find that the BCG luminosity depends weakly on overall cluster mass as L_BCG \\propto M_cl^0.18+-0.07, consistent with previous work. We found that 90% of the BCGs are located within 0.035 R_500 of the peak of the X-ray emission, including all of the cool core (CC) clusters. We also found an unexpected correlation between the BCG metric luminosity and the core gas density for non-cool core (non-CC) clusters, following a power law of n_e \\propto L_BCG^2.7+-0.4 (where n_e is measured at 0.008 R_500). The correlation is not easily explained by star formation (which is weak in non-CC clusters) or overall cluster mass (wh...