1,479 research outputs found
On Poincare and logarithmic Sobolev inequalities for a class of singular Gibbs measures
This note, mostly expository, is devoted to Poincar{\'e} and log-Sobolev
inequalities for a class of Boltzmann-Gibbs measures with singular interaction.
Such measures allow to model one-dimensional particles with confinement and
singular pair interaction. The functional inequalities come from convexity. We
prove and characterize optimality in the case of quadratic confinement via a
factorization of the measure. This optimality phenomenon holds for all beta
Hermite ensembles including the Gaussian unitary ensemble, a famous exactly
solvable model of random matrix theory. We further explore exact solvability by
reviewing the relation to Dyson-Ornstein-Uhlenbeck diffusion dynamics admitting
the Hermite-Lassalle orthogonal polynomials as a complete set of
eigenfunctions. We also discuss the consequence of the log-Sobolev inequality
in terms of concentration of measure for Lipschitz functions such as maxima and
linear statistics.Comment: Minor improvements. To appear in Geometric Aspects of Functional
Analysis -- Israel Seminar (GAFA) 2017-2019", Lecture Notes in Mathematics
225
Prostate Cancer and Race
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72215/1/j.1525-1497.2003.30801.x.pd
Effect of betaine supplementation on plasma nitrate/nitrite in exercise-trained men
Background: Betaine, beetroot juice, and supplemental nitrate have recently been reported to improve certain aspects of exercise performance, which may be mechanistically linked to increased nitric oxide. The purpose of the present study was to investigate the effect of betaine supplementation on plasma nitrate/nitrite, a surrogate marker or nitric oxide, in exercise-trained men.Methods: We used three different study designs (acute intake of betaine at 1.25 and 5.00 grams, chronic intake of betaine at 2.5 grams per day for 14 days, and chronic [6 grams of betaine per day for 7 days] followed by acute intake [6 grams]), all involving exercise-trained men, to investigate the effects of orally ingested betaine on plasma nitrate/nitrite. Blood samples were collected before and at 30, 60, 90, and 120 min after ingestion of 1.25 and 5.00 grams of betaine (Study 1); before and after 14 days of betaine supplementation at a dosage of 2.5 grams (Study 2); and before and after 7 days of betaine supplementation at a dosage of 6 grams, followed by acute ingestion of 6 grams and blood measures at 30 and 60 min post ingestion (Study 3).Results: In Study 1, nitrate/nitrite was relatively unaffected and no statistically significant interaction (p = 0.99), dosage (p = 0.69), or time (p = 0.91) effects were noted. Similar findings were noted in Study 2, with no statistically significant interaction (p = 0.57), condition (p = 0.98), or pre/post intervention (p = 0.17) effects noted for nitrate/nitrite. In Study 3, no statistically significant changes were noted in nitrate/nitrite between collection times (p = 0.97).Conclusion: Our data indicate that acute or chronic ingestion of betaine by healthy, exercise-trained men does not impact plasma nitrate/nitrite. These findings suggest that other mechanisms aside from increasing circulating nitric oxide are likely responsible for any performance enhancing effect of betaine supplementation. © 2011 Bloomer et al; licensee BioMed Central Ltd
Dendritic cell defects in patients with cancer: mechanisms and significance
Dendritic cells (DCs) are a complex network of antigen-presenting cells that have an essential role in the modulation of primary immunity. There has been increasing evidence that DCs isolated from patients with malignancy demonstrate functional deficiencies that inhibit the capacity to mount an effective anti-tumor response. In this issue of Breast Cancer Research, Pinzon-Charry and colleagues investigate one of the possible mechanisms by which tumors induce DC dysfunction to evade host immune surveillance. They demonstrate that DCs isolated from the circulation of patients with early-stage breast cancer exhibit increased rates of spontaneous apoptosis. In vitro studies suggest that a soluble factor secreted by breast cancer cells is responsible for this phenomenon. In contrast, ex vivo conditioning of DCs with CD-40 ligand and IL-12 was protective against tumor-induced apoptosis
Does HIV adversely influence the outcome in advanced non-small-cell lung cancer in the era of HAART?
Cardiorespiratory and perceptual responses to self-regulated and imposed submaximal arm-leg ergometry
Purpose:
This study compared cardiorespiratory and perceptual responses to exercise using self-regulated and imposed power outputs distributed between the arms and legs.
Methods
Ten males (age 21.7 ± 3.4 years) initially undertook incremental arm-crank ergometry (ACE) and cycle ergometry (CYC) tests to volitional exhaustion to determine peak power output (Wpeak). Two subsequent tests involved 20-min combined arm–leg ergometry (ALE) trials, using imposed and self-regulated protocols, both of which aimed to elicit an exercising heart rate of 160 beats min−1. During the imposed trial, arm and leg intensity were set at 40% of each ergometer-specific Wpeak. During the self-regulated trial, participants were asked to self-regulate cadence and resistance to achieve the target heart rate. Heart rate (HR), oxygen uptake (V˙O2
), pulmonary ventilation (V˙E
), and ratings of perceived exertion (RPE) were recorded continuously.
Results
As expected, there were no differences between imposed and self-regulated trials for HR, V˙O2
, and V˙E
(all P ≥ 0.05). However, central RPE and local RPE for the arms were lower during self-regulated compared imposed trials (P ≤ 0.05). Lower RPE during the self-regulated trial was related to preferential adjustments in how the arms (33 ± 5% Wpeak) and legs (46 ± 5% Wpeak) contributed to the exercise intensity.
Conclusions:
This study demonstrates that despite similar metabolic and cardiovascular strain elicited by imposed and self-regulated ALE, the latter was perceived to be less strenuous, which is related to participants doing more work with the legs and less work with the arms to achieve the target intensity
Predictors of linkage to care following community-based HIV counseling and testing in rural Kenya
Despite innovations in HIV counseling and testing (HCT), important gaps remain in understanding linkage to care. We followed a cohort diagnosed with HIV through a community-based HCT campaign that trained persons living with HIV/AIDS (PLHA) as navigators. Individual, interpersonal, and institutional predictors of linkage were assessed using survival analysis of self-reported time to enrollment. Of 483 persons consenting to follow-up, 305 (63.2%) enrolled in HIV care within 3 months. Proportions linking to care were similar across sexes, barring a sub-sample of men aged 18–25 years who were highly unlikely to enroll. Men were more likely to enroll if they had disclosed to their spouse, and women if they had disclosed to family. Women who anticipated violence or relationship breakup were less likely to link to care. Enrolment rates were significantly higher among participants receiving a PLHA visit, suggesting that a navigator approach may improve linkage from community-based HCT campaigns.Vestergaard Frandse
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