187 research outputs found
Some generating functions for q-polynomials
We obtain q-analogues of the Sylvester, Ces\`aro, Pasternack, and Bateman
polynomials. We also derive generating functions for these polynomials.Comment: 10 page
Retrieval of displaced dental implant in maxillary sinus by modified Caldwell Luc technique
Displacement of dental implants into the maxillary sinus is an uncommon complication during implant placement. Here we present a case report of retrieval of dental implant displaced in the maxillary sinus with modification of Caldwell-Luc technique. A 35-year-old man presented to our institution for replacement of the maxillary right first molar using dental implant. At the point of final tightening of the implant, it suddenly got displaced into the maxillary sinus. The displaced dental implant was retrieved by performing a modification of the Caldwell-Luc technique which utilises gravitational force, saline as a vehicle and a tight-fitting suction tip in the surgically created lateral window. He was also instructed in coughing and sneezing techniques. Medical and dental professionals can utilise this technique effectively when advanced equipment such as endoscopes are not available to retrieve dental implants displaced in the maxillary sinus and it also preserves significant amount of alveolar bone in comparison to the traditional Caldwell Luc techniqu
Edge-weighting of gene expression graphs
In recent years, considerable research efforts have been directed to micro-array technologies and their role in providing simultaneous information on expression profiles for thousands of genes. These data, when subjected to clustering and classification procedures, can assist in identifying patterns and providing insight on biological processes. To understand the properties of complex gene expression datasets, graphical representations can be used. Intuitively, the data can be represented in terms of a bipartite graph, with weighted edges corresponding to gene-sample node couples in the dataset. Biologically meaningful subgraphs can be sought, but performance can be influenced both by the search algorithm, and, by the graph-weighting scheme and both merit rigorous investigation. In this paper, we focus on edge-weighting schemes for bipartite graphical representation of gene expression. Two novel methods are presented: the first is based on empirical evidence; the second on a geometric distribution. The schemes are compared for several real datasets, assessing efficiency of performance based on four essential properties: robustness to noise and missing values, discrimination, parameter influence on scheme efficiency and reusability. Recommendations and limitations are briefly discussed
Phase Transitions in Higher Derivative Gravity
This paper deals with black holes, bubbles and orbifolds in Gauss-Bonnet
theory in five dimensional anti de Sitter space. In particular, we study
stable, unstable and metastable phases of black holes from thermodynamical
perspective. By comparing bubble and orbifold geometries, we analyse associated
instabilities. Assuming AdS/CFT correspondence, we discuss the effects of this
higher derivative bulk coupling on a specific matrix model near the critical
points of the boundary gauge theory at finite temperature. Finally, we propose
another phenomenological model on the boundary which mimics various phases of
the bulk space-time.Comment: 33 pages, 12 figures, LaTeX, typos corrected, clarifications in
sections 5 and 6, references adde
Quantum Discord in a spin-1/2 transverse XY Chain Following a Quench
We report a study on the zero-temperature quantum discord as a measure of
two-spin correlation of a transverse XY spin chain following a quench across a
quantum critical point and investigate the behavior of mutual information,
classical correlations and hence of discord in the final state as a function of
the rate of quenching. We show that though discord vanishes in the limit of
very slow as well as very fast quenching, it exhibits a peak for an
intermediate value of the quenching rate. We show that though discord and also
the mutual information exhibit a similar behavior with respect to the quenching
rate to that of concurrence or negativity following an identical quenching,
there are quantitative differences. Our studies indicate that like concurrence,
discord also exhibits a power law scaling with the rate of quenching in the
limit of slow quenching though it may not be expressible in a closed power law
form. We also explore the behavior of discord on quenching linearly across a
quantum multicritical point (MCP) and observe a scaling similar to that of the
defect density.Comment: 6 pages, 5 figure
Formation of regulatory modules by local sequence duplication
Turnover of regulatory sequence and function is an important part of
molecular evolution. But what are the modes of sequence evolution leading to
rapid formation and loss of regulatory sites? Here, we show that a large
fraction of neighboring transcription factor binding sites in the fly genome
have formed from a common sequence origin by local duplications. This mode of
evolution is found to produce regulatory information: duplications can seed new
sites in the neighborhood of existing sites. Duplicate seeds evolve
subsequently by point mutations, often towards binding a different factor than
their ancestral neighbor sites. These results are based on a statistical
analysis of 346 cis-regulatory modules in the Drosophila melanogaster genome,
and a comparison set of intergenic regulatory sequence in Saccharomyces
cerevisiae. In fly regulatory modules, pairs of binding sites show
significantly enhanced sequence similarity up to distances of about 50 bp. We
analyze these data in terms of an evolutionary model with two distinct modes of
site formation: (i) evolution from independent sequence origin and (ii)
divergent evolution following duplication of a common ancestor sequence. Our
results suggest that pervasive formation of binding sites by local sequence
duplications distinguishes the complex regulatory architecture of higher
eukaryotes from the simpler architecture of unicellular organisms
Correlators of Giant Gravitons from dual ABJ(M) Theory
We generalize the operators of ABJM theory, given by Schur polynomials, in
ABJ theory by computing the two point functions in the free field and at finite
limits. These polynomials are then identified with the states of
the dual gravity theory. Further, we compute correlators among giant gravitons
as well as between giant gravitons and ordinary gravitons through the
corresponding correlators of ABJ(M) theory. Finally, we consider a particular
non-trivial background produced by an operator with an -charge of
and find, in presence of this background, due to the contribution of
the non-planar corrections, the large expansion is replaced by
and respectively.Comment: Latex, 32+1 pages, 2 figures, journal versio
The Toronto Mindfulness Scale and the State Mindfulness Scale: psychometric properties of the Spanish versions
Objectives The Toronto Mindfulness Scale (TMS) and the State Mindfulness Scale (SMS) are two relevant self-report measures of state mindfulness. The purpose of this study was to examine the internal structure and to offer evidence of the reliability and validity of the Spanish versions of the TMS and SMS.MethodsData from six distinct non-clinical samples in Spain were obtained. They responded to the TMS (n = 119), SMS (n = 223), and measures of trait mindfulness, decentering, non-attachment, depression, anxiety, stress, positive and negative affect, self-criticism, and self-reassurance. The internal structure of the TMS and SMS was analyzed through confirmatory factor analysis. Reliability, construct validity, and sensitivity to change analyses were performed.ResultsThe correlated two-factor structure (curiosity and decentering) was the best-fitting model for the TMS (CFI = 0.932; TLI = 0.913; RMSEA = 0.100 [0.077–0.123]; WRMR = 0.908). The bifactor structure (general factor, mindfulness of body, and mindfulness of mind) was the best-fitting model for the SMS (CFI = 0.961; TLI = 0.950; RMSEA = 0.096 [0.086–0.106]; WRMR = 0.993). Adequate reliability was found for both measures. The reliability of the SMS specific factors was very poor when controlling for the general factor. The patterns of correlations were mainly as expected and according to previous literature. The TMS and SMS have been able to detect state mindfulness changes after different meditation practices.ConclusionValidity evidence is provided to support the use of the TMS and SMS in Spanish populations, though the reliability of the SMS specific factors merit revision
BariSurg trial: Sleeve gastrectomy versus Roux-en-Y gastric bypass in obese patients with BMI 35–60 kg/m2 – a multi-centre randomized patient and observer blind non-inferiority trial
Background: Roux-en-Ygastric bypass (RYGB) and sleeve gastrectomy (SG) rank among the most frequently applied bariatric procedures worldwide due to their positive risk/benefit correlation. A systematic review revealed a similar excess weight loss (EWL) 2 years postoperatively between SG and RYGB. However, there is a lack of randomized controlled multi-centre trials comparing SG and RYGB, not only concerning EWL, but also in terms of remission of obesity-related co-morbidities, gastroesophageal reflux disease (GERD) and quality of life (QoL) in the mid- and long-term. Methods: The BariSurg trial was designed as a multi-centre, randomized controlled patient and observer blind trial. The trial protocol was approved by the corresponding ethics committees of the centres. To demonstrate EWL non-inferiority of SG compared to RYGB, power calculation was performed according to a non-inferiority study design. Morbidity, mortality, remission of obesity-related co-morbidities, GERD course and QoL are major secondary endpoints. 248 patients between 18 and 70 years, with a body mass index (BMI) between 35–60 kg/m2 and indication for bariatric surgery according to the most recent German S3-guidelines will be randomized. The primary and secondary endpoints will be assessed prior to surgery and afterwards at discharge and at the time points 3–6, 12, 24, 36, 48 and 60 months postoperatively. Discussion: With its five year follow-up, the BariSurg-trial will provide further evidence based data concerning the impact of SG and RYGB on EWL, remission of obesity-related co-morbidities, the course of GERD and QoL. Trial registration: The trial protocol has been registered in the German Clinical Trials Register DRKS0000476
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