240 research outputs found
Anyonic behavior of quantum group gases
We first introduce and discuss the formalism of -bosons and fermions
and consider the simplest Hamiltonian involving these operators. We then
calculate the grand partition function for these models and study the high
temperature (low density) case of the corresponding gases for . We show
that quantum group gases exhibit anyonic behavior in and spatial
dimensions. In particular, for a boson gas at the parameter
interpolates within a wider range of attractive and repulsive systems than the
anyon statistical parameter.Comment: LaTeX file, 19 pages, two figures ,uses epsf.st
The effect of sarcopenia on postoperative outcomes following emergency laparotomy: a systematic review and meta-analysis
Emergency laparotomy procedures have high rates of postoperative mortality and morbidity in older patient. Sarcopenia is associated with poor postoperative outcomes in elective surgeries and there is growing evidence for its use as a risk predictor in the emergency setting. The study aimed to evaluate the effect of sarcopenia on postoperative mortality and morbidity following emergency laparotomy. Five electronic databases were systematically searched (MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, and Web of Science) from conception until the 14th February 2022. All prospective cohort studies were included. Risk of bias was assessed with the Newcastle-Ottawa score. Pooled meta-analyses were estimated using the Mantel-Haenszel and inverse-generic variance method for mortality and morbidity outcomes. Eleven retrospective cohort studies were included, of which ten were included in the meta-analysis comprising of 3492 patients (1027 sarcopenic, 2465 non-sarcopenic). The study level incidence of sarcopenia ranged from 24.6 to 50.3% with a median rate of 25.1%. Sarcopenia was associated with increased 30-day mortality (OR 2.36, 95% CI, 1.66, 3.37, I2 = 43%), 90-day mortality (OR 2.51, 95% CI, 1.79, 3.52, I2 = 0%), and length of hospital stay (in days) (MD 1.18, 95% CI, 0.42, 1.94, I2 = 0%, P=0.002), but not incidence of postoperative major complications (OR 1.49, 95% CI, 0.86, 2.56, I2 = 70%, P = 0.15). Sarcopenia predicts poor outcomes following emergency laparotomy. We suggest assessment of sarcopenia should be incorporated into acute surgical assessment to identify high risk patients and inform clinical decision-making prior to an emergency laparotomy
Generalized Fock Spaces, New Forms of Quantum Statistics and their Algebras
We formulate a theory of generalized Fock spaces which underlies the
different forms of quantum statistics such as ``infinite'', Bose-Einstein and
Fermi-Dirac statistics. Single-indexed systems as well as multi-indexed systems
that cannot be mapped into single-indexed systems are studied. Our theory is
based on a three-tiered structure consisting of Fock space, statistics and
algebra. This general formalism not only unifies the various forms of
statistics and algebras, but also allows us to construct many new forms of
quantum statistics as well as many algebras of creation and destruction
operators. Some of these are : new algebras for infinite statistics,
q-statistics and its many avatars, a consistent algebra for fractional
statistics, null statistics or statistics of frozen order, ``doubly-infinite''
statistics, many representations of orthostatistics, Hubbard statistics and its
variations.Comment: This is a revised version of the earlier preprint: mp_arc 94-43.
Published versio
Towards a global land surface climate fiducial reference measurements network
There is overwhelming evidence that the climate system has warmed since the instigation of instrumental meteorological observations. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change concluded that the evidence for warming was unequivocal. However, owing to imperfect measurements and ubiquitous changes in measurement networks and techniques, there remain uncertainties in many of the details of these historical changes. These uncertainties do not call into question the trend or overall magnitude of the changes in the global climate system. Rather, they act to make the picture less clear than it could be, particularly at the local scale where many decisions regarding adaptation choices will be required, both now and in the future. A set of high-quality long-term fiducial reference measurements of essential climate variables will enable future generations to make rigorous assessments of future climate change and variability, providing society with the best possible information to support future decisions. Here we propose that by implementing and maintaining a suitably stable and metrologically well-characterized global land surface climate fiducial reference measurements network, the present-day scientific community can bequeath to future generations a better set of observations. This will aid future adaptation decisions and help us to monitor and quantify the effectiveness of internationally agreed mitigation steps. This article provides the background, rationale, metrological principles, and practical considerations regarding what would be involved in such a network, and outlines the benefits which may accrue. The challenge, of course, is how to convert such a vision to a long-term sustainable capability providing the necessary well-characterized measurement series to the benefit of global science and future generations
An empirical investigation of dance addiction
Although recreational dancing is associated with increased physical and psychological well-being, little is known about the harmful effects of excessive dancing. The aim of the present study was to explore the psychopathological factors associated with dance addiction. The sample comprised 447 salsa and ballroom dancers (68% female, mean age: 32.8 years) who danced recreationally at least once a week. The Exercise Addiction Inventory (Terry, Szabo, & Griffiths, 2004) was adapted for dance (Dance Addiction Inventory, DAI). Motivation, general mental health (BSI-GSI, and Mental Health Continuum), borderline personality disorder, eating disorder symptoms, and dance motives were also assessed. Five latent classes were explored based on addiction symptoms with 11% of participants belonging to the most problematic class. DAI was positively associated with psychiatric distress, borderline personality and eating disorder symptoms. Hierarchical linear regression model indicated that Intensity (ß=0.22), borderline (ß=0.08), eating disorder (ß=0.11) symptoms, as well as Escapism (ß=0.47) and Mood Enhancement (ß=0.15) (as motivational factors) together explained 42% of DAI scores. Dance addiction as assessed with the Dance Addiction Inventory is associated with indicators of mild psychopathology and therefore warrants further research
Morphological evidence for an invasion-independent metastasis pathway exists in multiple human cancers
BACKGROUND: We have previously described an alternative invasion-independent pathway of cancer metastasis in a murine mammary tumor model. This pathway is initiated by intravasation of tumor nests enveloped by endothelial cells of sinusoidal vasculature within the tumor. In this study, we examined whether evidence for the invasion-independent pathway of metastasis is present in human cancers. METHODS: Archival specimens of 10 common types of human cancers were examined for the presence of sinusoidal vasculature enveloping tumor nests and subsequently generated endothelial-covered tumor emboli in efferent veins. RESULTS: A percentage of tumor emboli in all cancers was found to be enveloped by endothelial cells, but these structures were particularly prevalent in renal cell carcinomas, hepatocellular carcinomas and follicular thyroid carcinomas. A common feature of the vasculature in these tumors was the presence of dilated sinusoid-like structures surrounding tumor nests. A high mean vascular area within tumors, an indication of sinusoidal vascular development, was significantly related to the presence of endothelial-covered tumor emboli. CONCLUSIONS: These results suggest that an invasion-independent metastatic pathway is possible in a wide variety of human cancers. Further investigation of this phenomenon may present new therapeutic strategies for the amelioration of cancer metastasis
High density of peritumoral lymphatic vessels is a potential prognostic marker of endometrial carcinoma: a clinical immunohistochemical method study
<p>Abstract</p> <p>Background</p> <p>The lymphatic system is a major route for cancer cell dissemination and also a potential target for antitumor therapy. To investigate whether increased lymphatic vessel density (LVD) is a prognostic factor for nodal metastasis and survival, we studied peritumoral LVD (P-LVD) and intratumoral LVD (I-LVD) in samples from 102 patients with endometrial carcinoma;</p> <p>Methods</p> <p>Endometrial carcinoma tissues were analyzed for lymphatic vessels by immunohistochemical staining with an antibody against LYVE-1. Univariate analysis was performed with Kaplan-Meier life-table curves to estimate survival, and was compared using the log rank test. Prognostic models used multivariate Cox regression analysis for multivariate analyses of survival;</p> <p>Results</p> <p>Our study showed that P-LVD, but not I-LVD, was significantly correlated with lymph vascular space invasion (LVSI), lymph node metastasis, tumor stage, and CD44 expression in endometrial carcinoma. Moreover, P-LVD was an independent prognostic factor for progression-free survival and overall survival of endometrial carcinoma;</p> <p>Conclusions</p> <p>P-LVD may serve as a prognostic factor for endometrial carcinoma. The peritumoral lymphatics might play an important role in lymphatic vessel metastasis.</p
Clinical significance of serum and urinary HER2/neu protein levels in primary non-muscle invasive bladder cancer
Protein kinase D1 regulates matrix metalloproteinase expression and inhibits breast cancer cell invasion
Membrane-Associated RING-CH Proteins Associate with Bap31 and Target CD81 and CD44 to Lysosomes
Membrane-associated RING-CH (MARCH) proteins represent a family of transmembrane ubiquitin ligases modulating intracellular trafficking and turnover of transmembrane protein targets. While homologous proteins encoded by gamma-2 herpesviruses and leporipoxviruses have been studied extensively, limited information is available regarding the physiological targets of cellular MARCH proteins. To identify host cell proteins targeted by the human MARCH-VIII ubiquitin ligase we used stable isotope labeling of amino-acids in cell culture (SILAC) to monitor MARCH-dependent changes in the membrane proteomes of human fibroblasts. Unexpectedly, we observed that MARCH-VIII reduced the surface expression of Bap31, a chaperone that predominantly resides in the endoplasmic reticulum (ER). We demonstrate that Bap31 associates with the transmembrane domains of several MARCH proteins and controls intracellular transport of MARCH proteins. In addition, we observed that MARCH-VIII reduced the surface expression of the hyaluronic acid-receptor CD44 and both MARCH-VIII and MARCH-IV sequestered the tetraspanin CD81 in endo-lysosomal vesicles. Moreover, gene knockdown of MARCH-IV increased surface levels of endogenous CD81 suggesting a constitutive involvement of this family of ubiquitin ligases in the turnover of tetraspanins. Our data thus suggest a role of MARCH-VIII and MARCH-IV in the regulated turnover of CD81 and CD44, two ubiquitously expressed, multifunctional proteins
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