192 research outputs found
Comparing a few distributions of transverse momenta in high energy collisions
Transverse momentum spectra of particles produced in high energy collisions
are very important due to their relations to the excitation degree of
interacting system. To describe the transverse momentum spectra, one can use
more than one probability density functions of transverse momenta, which are
simply called the functions or distributions of transverse momenta in some
cases. In this paper, a few distributions of transverse momenta in high energy
collisions are compared with each other in terms of plots to show some
quantitative differences. Meanwhile, in the framework of Tsallis statistics,
the distributions of momentum components, transverse momenta, rapidities, and
pasudorapidities are obtained according to the analytical and Monte Carlo
methods. These analyses are useful to understand carefully different
distributions in high energy collisions.Comment: 11 pages, 7 figures. Results in Physics, Accepte
A new description of transverse momentum spectra of identified particles produced in proton-proton collisions at high energies
The transverse momentum spectra of identified particles produced in high
energy proton-proton () collisions are empirically described by a new
method with the framework of participant quark model or the multisource model
at the quark level, in which the source itself is exactly the participant
quark. Each participant (constituent) quark contributes to the transverse
momentum spectrum, which is described by the TP-like function, a revised
Tsallis--Pareto-type function. The transverse momentum spectrum of the hadron
is the convolution of two or more TP-like functions. For a lepton, the
transverse momentum spectrum is the convolution of two TP-like functions due to
two participant quarks, e.g. projectile and target quarks, taking part in the
collisions. A discussed theoretical approach seems to describe the
collisions data at center-of-mass energy GeV, 2.76 TeV, and 13
TeV very well.Comment: 19 pages, 7 figures. Advances in High Energy Physics, accepte
An analysis of transverse momentum spectra of various jets produced in high energy collisions
With the framework of the multi-source thermal model, we analyze the
experimental transverse momentum spectra of various jets produced in different
collisions at high energies. Two energy sources, a projectile participant quark
and a target participant quark, are considered. Each energy source (each
participant quark) is assumed to contribute to the transverse momentum
distribution to be the TP-like function, i.e. a revised Tsallis--Pareto-type
function. The contribution of the two participant quarks to the transverse
momentum distribution is then the convolution of two TP-like functions. The
model distribution can be used to fit the experimental spectra measured by
different collaborations. The related parameters such as the entropy
index-related, effective temperature, and revised index are then obtained. The
trends of these parameters are useful to understand the characteristic of high
energy collisions.Comment: 18 pages, 11 figures. Advances in High Energy Physics, accepte
Rapidity and Energy Dependences of Temperatures and Volume Extracted from Identified Charged Hadron Spectra in Proton-Proton Collisions at a Super Proton Synchrotron (SPS)
The standard (Bose-Einstein/Fermi-Dirac or Maxwell-Boltzmann) distribution
from the relativistic ideal gas model is used to study the transverse momentum
() spectra of identified charged hadrons (, , ,
, , and ) with different rapidities produced in inelastic
proton-proton () collisions at the Super Proton Synchrotron (SPS). The
experimental data measured by the NA61/SHINE Collaboration at the
center-of-mass (c.m.) energies , 7.7, 8.8, 12.3, and 17.3 GeV are
fitted well by the distribution. It is shown that the effective temperature
( or ), kinetic freeze-out temperature (), and initial
temperature () decrease with the increase in rapidity and increase with
the increase in c.m. energy. The kinetic freeze-out volume () extracted from
the , , , , and spectra decreases with the
rapidity and increase with the c.m. energy. The opposite tendency of ,
extracted from the spectra, is observed to be increasing with the rapidity
and decreasing with the c.m. energy due to the effect of leading protons.Comment: 27 pages, 14 figures. Entropy, accepte
Pathological Ace2-to-Ace enzyme switch in the stressed heart is transcriptionally controlled by the endothelial Brg1–FoxM1 complex
Genes encoding angiotensin-converting enzymes (Ace and Ace2) are essential for heart function regulation. Cardiac stress enhances Ace, but suppresses Ace2, expression in the heart, leading to a net production of angiotensin II that promotes cardiac hypertrophy and fibrosis. The regulatory mechanism that underlies the Ace2-to-Ace pathological switch, however, is unknown. Here we report that the Brahma-related gene-1 (Brg1) chromatin remodeler and forkhead box M1 (FoxM1) transcription factor cooperate within cardiac (coronary) endothelial cells of pathologically stressed hearts to trigger the Ace2-to-Ace enzyme switch, angiotensin I-to-II conversion, and cardiac hypertrophy. In mice, cardiac stress activates the expression of Brg1 and FoxM1 in endothelial cells. Once activated, Brg1 and FoxM1 form a protein complex on Ace and Ace2 promoters to concurrently activate Ace and repress Ace2, tipping the balance to Ace2 expression with enhanced angiotensin II production, leading to cardiac hypertrophy and fibrosis. Disruption of endothelial Brg1 or FoxM1 or chemical inhibition of FoxM1 abolishes the stress-induced Ace2-to-Ace switch and protects the heart from pathological hypertrophy. In human hypertrophic hearts, BRG1 and FOXM1 expression is also activated in endothelial cells; their expression levels correlate strongly with the ACE/ACE2 ratio, suggesting a conserved mechanism. Our studies demonstrate a molecular interaction of Brg1 and FoxM1 and an endothelial mechanism of modulating Ace/Ace2 ratio for heart failure therapy
Epicardial calcineurin-NFAT signals through Smad2 to direct coronary smooth muscle cell and arterial wall development
AIMS:
Congenital coronary artery anomalies produce serious events that include syncope, arrhythmias, myocardial infarction, or sudden death. Studying the mechanism of coronary development will contribute to the understanding of the disease and help design new diagnostic or therapeutic strategies. Here, we characterized a new calcineurin-NFAT signalling which specifically functions in the epicardium to regulate the development of smooth muscle wall of the coronary arteries.
METHODS AND RESULTS:
Using tissue-specific gene deletion, we found that calcineurin-NFAT signals in the embryonic epicardium to direct coronary smooth muscle cell development. The smooth muscle wall of coronary arteries fails to mature in mice with epicardial deletion of calcineurin B1 (Cnb1), and accordingly these mutant mice develop cardiac dysfunction with reduced exercise capacity. Inhibition of calcineurin at various developmental windows shows that calcineurin-NFAT signals within a narrow time window at embryonic Day 12.5-13.5 to regulate coronary smooth muscle cell development. Within the epicardium, NFAT transcriptionally activates the expression of Smad2, whose gene product is critical for transducing transforming growth factor β (TGFβ)-Alk5 signalling to control coronary development.
CONCLUSION:
Our findings demonstrate new spatiotemporal and molecular actions of calcineurin-NFAT that dictate coronary arterial wall development and a new mechanism by which calcineurin-NFAT integrates with TGFβ signalling during embryonic development
Prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan
<p>Abstract</p> <p>Background</p> <p>In Taiwan, a distinct ethnic group variation in incidence and mortality rates has been suggested for most carcinomas. Our aim is to identify the role of prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan.</p> <p>Methods</p> <p>Taiwan Cancer Registry records of 9039 subjects diagnosed with oral and pharyngeal carcinoma were analyzed. The population was divided into three ethnic groups by residence, which were Taiwanese aborigines, Hakka and Hokkien communities. Five-year survival rates were estimated by Kaplan-Meier methods. Ethnic curves differed significantly by log-rank test; therefore separate models for Taiwanese aborigines, Hakka and Hokkien were carried out. The Cox multivariate proportional hazards model was used to examine the role of prognostic factors on ethnic survival.</p> <p>Results</p> <p>The five-year survival rates of oral and pharyngeal carcinoma were significantly poorer for Hokkien community (53.9%) and Taiwanese aborigines community (58.1%) compared with Hakka community (60.5%). The adjusted hazard ratio of Taiwanese aborigines versus Hakka was 1.07 (95%CI, 0.86–1.33) for oral and pharyngeal carcinoma mortality, and 1.16 (95%CI, 1.01–1.33) for Hokkien versus Hakka. Males had significantly poor prognosis than females. Subjects with tongue and/or mouth carcinoma presented the worst prognosis, whereas lip carcinoma had the best prognosis. Subjects with verrucous carcinoma had better survival than squamous cell carcinoma. Prognosis was the worst in elderly subjects, and subjects who underwent surgery had the highest survival rate.</p> <p>Conclusion</p> <p>Our study presented that predictive variables in oral and pharyngeal carcinoma survival have been: ethnic groups, period of diagnosis, gender, diagnostic age, anatomic site, morphologic type, and therapy.</p
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