222 research outputs found
The structure and dynamics of young star clusters: King 16, NGC 1931, NGC 637 and NGC 189
In this paper, using 2MASS photometry, we study the structural and dynamical
properties of four young star clusters viz. King 16, NGC 1931, NGC 637 and NGC
189. For the clusters King 16, NGC 1931, NGC 637 and NGC 189, we obtain the
limiting radii of 7', 12', 6' and 5' which correspond to linear radii of 3.6
pc, 8.85 pc, 3.96 pc and 2.8 pc respectively. The reddening values
obtained for the clusters are 0.85, 0.65--0.85, 0.6 and 0.53 and their true
distances are 1786 pc, 3062 pc, 2270 pc and 912 pc respectively. Ages of the
clusters are 6 Myr, 4 Myr, 4 Myr and 10 Myr respectively. We compare their
structures, luminosity functions and mass functions () to the parameter to study the star
formation process and the dynamical evolution of these clusters. We find that,
for our sample, mass seggregation is observed in clusters or their cores only
when the ages of the clusters are comparable to their relaxation times (). These results suggest mass seggregation due to dynamical effects. The
values of , which characterise the overall mass functions for the
clusters are 0.96 0.11, 1.16 0.18, 0.55 0.14 and 0.66
0.31 respectively. The change in as a function of radius is a good
indicator of the dynamical state of clusters.Comment: Accepted for publication in Astrophysics & Space Scienc
Theory of Coexistence of Superconductivity and Ferroelectricity : A Dynamical Symmetry Model
We propose and investigate a model for the coexistence of Superconductivity
(SC) and Ferroelectricity (FE) based on the dynamical symmetries for
the pseudo-spin SC sector, for the displaced oscillator FE sector, and
for the composite system. We assume a minimal
symmetry-allowed coupling, and simplify the hamiltonian using a double mean
field approximation (DMFA). A variational coherent state (VCS) trial
wave-function is used for the ground state: the energy, and the relevant order
parameters for SC and FE are obtained. For positive sign of the SC-FE coupling
coefficient, a non-zero value of either order parameter can suppress the other
(FE polarization suppresses SC and vice versa). This gives some support to
"Matthias' Conjecture" [1964], that SC and FE tend to be mutually exclusive.
For such a Ferroelectric Superconductor we predict: a) the SC gap
(and ) will increase with increasing applied pressure when pressure
quenches FE as in many ferroelectrics, and b) the FE polarization will increase
with increaesing magnetic field up to . The last result is equivalent to
the prediction of a new type of Magneto-Electric Effect in a coexistent SC-FE
material. Some discussion will be given of the relation of these results to the
cuprate superconductors.Comment: 46 page
The effect of glucagon-like peptide-1 receptor agonists liraglutide and semaglutide on cardiovascular and renal outcomes across baseline blood pressure categories: Analysis of the LEADER and SUSTAIN 6 trials
It is unknown if the cardioprotective and renal effects of glucagon-like peptide-1 receptor agonists are consistent across blood pressure (BP) categories in patients with type 2 diabetes and at high risk of cardiovascular events. Using data from the LEADER (9340 patients) and SUSTAIN 6 (3297 patients) trials, we evaluated post hoc the cardiorenal effect of liraglutide and semaglutide on major adverse cardiovascular events (MACE) and nephropathy by baseline BP categories using a Cox proportional hazards model (treatment and subgroup as factors; adjusted for cardiorenal risk factors). Data from the two trials were analysed separately. In the LEADER and SUSTAIN 6 trials, the prevalence of stage 1 hypertension was 30% and 31%, respectively, and of stage 2 hypertension 41% and 43%, respectively. There was no statistical heterogeneity across the BP categories for the effects of liraglutide (P =.06 for MACE; P =.14 for nephropathy) or semaglutide (P =.40 for MACE; P =.27 for nephropathy) versus placebo. This implies that liraglutide and semaglutide may be beneficial for patients with type 2 diabetes, irrespective of their baseline BP
Temperature-dependent magnetization in diluted magnetic semiconductors
We calculate magnetization in magnetically doped semiconductors assuming a
local exchange model of carrier-mediated ferromagnetic mechanism and using a
number of complementary theoretical approaches. In general, we find that the
results of our mean-field calculations, particularly the dynamical mean field
theory results, give excellent qualitative agreement with the experimentally
observed magnetization in systems with itinerant charge carriers, such as
Ga_{1-x}Mn_xAs with 0.03 < x < 0.07, whereas our percolation-theory-based
calculations agree well with the existing data in strongly insulating
materials, such as Ge_{1-x}Mn_x. We comment on the issue of non-mean-field like
magnetization curves and on the observed incomplete saturation magnetization
values in diluted magnetic semiconductors from our theoretical perspective. In
agreement with experimental observations, we find the carrier density to be the
crucial parameter determining the magnetization behavior. Our calculated
dependence of magnetization on external magnetic field is also in excellent
agreement with the existing experimental data.Comment: 17 pages, 15 figure
Effects of glucagon-like peptide-1 receptor agonists liraglutide and semaglutide on cardiovascular and renal outcomes across body mass index categories in type 2 diabetes: Results of the LEADER and SUSTAIN 6 trials
35 and ≥35 kg/m2), and CV and kidney outcomes with GLP-1 RA versus placebo were analysed. All baseline BMI data from LEADER (n = 9331) and SUSTAIN 6 (n = 3290) were included (91% and 92% of patients with overweight or obesity, respectively). In SUSTAIN 6, nominally significant heterogeneity of semaglutide efficacy by baseline BMI was observed for CV death/myocardial infarction/stroke (major adverse CV events, primary outcome of both25, ≥25-<Associations between body mass index (BMI) and the cardiovascular (CV) and kidney efficacy of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with type 2 diabetes (T2D) are uncertain; therefore, data analysed separately from the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial and the Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide in Subjects with Type 2 Diabetes (SUSTAIN 6) were examined. These international, randomized, placebo-controlled trials investigated liraglutide and semaglutide (both subcutaneous) in patients with T2D and at high risk of CV events. In post hoc analyses, patients were categorized by baseline BMI (<25, ≥25-<30, ≥30-<35 and ≥35 kg/m2), and CV and kidney outcomes with GLP-1 RA versus placebo were analysed. All baseline BMI data from LEADER (n = 9331) and SUSTAIN 6 (n = 3290) were included (91% and 92% of patients with overweight or obesity, respectively). In SUSTAIN 6, nominally significant heterogeneity of semaglutide efficacy by baseline BMI was observed for CV death/myocardial infarction/stroke (major adverse CV events, primary outcome of both; Pinteraction =.02); otherwise, there was no statistical heterogeneity for either GLP-1 RA versus placebo across BMI categories for key CV and kidney outcomes. The lack of statistical heterogeneity from these cardiorenal outcomes implies that liraglutide and semaglutide may be beneficial for many patients and is probable not to depend on their baseline BMI, but further study is needed.therefore, data analysed separately from the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial and the Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide in Subjects with Type 2 Diabetes (SUSTAIN 6) were examined. These international, randomized, placebo-controlled trials investigated liraglutide and semaglutide (both subcutaneous) in patients with T2D and at high risk of CV events. In post hoc analyses, patients were categorized by baseline BMI (<Associations between body mass index (BMI) and the cardiovascular (CV) and kidney efficacy of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with type 2 diabetes (T2D) are uncertainPinteraction =.02)30, ≥30-<otherwise, there was no statistical heterogeneity for either GLP-1 RA versus placebo across BMI categories for key CV and kidney outcomes. The lack of statistical heterogeneity from these cardiorenal outcomes implies that liraglutide and semaglutide may be beneficial for many patients and is probable not to depend on their baseline BMI, but further study is needed
Liraglutide reduces cardiovascular events and mortality in type 2 diabetes mellitus independently of baseline low-density lipoprotein cholesterol levels and statin use results from the LEADER trial
The causal relationship between low-density lipoprotein cholesterol (LDL-C) and atherosclerotic cardiovascular events has been well established. In people with type 2 diabetes mellitus, LDL-C lowering with statins is strongly endorsed by clinical practice guidelines, with suggested LDL-C target levels including <100 mg/dL for high-risk patients, <70 mg/dL for very high-risk patients, and ≤55 mg/dL in patients with cardiovascular disease at extreme risk.2 Because LDL-C is a dominant pathophysiological mechanism of atherogenesis, questions pertain to whether newer antiatherosclerotic and cardiovascular protective therapies exhibit efficacy, even in the setting of low LDL-C. In this post hoc analysis of the LEADER trial, we evaluated the efficacy of liraglutide on cardiovascular outcomes and mortality across the spectrum of baseline LDL-C and statin use
Effects of liraglutide on cardiovascular outcomes in patients with type 2 diabetes mellitus with or without history of myocardial infarction or stroke: Post hoc analysis from the leader trial
Background: The glucagon-like peptide-1 analog liraglutide reduced cardiovascular events and mortality in patients with type 2 diabetes mellitus in the LEADER trial (Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes). In a post hoc analysis, we evaluated the efficacy of liraglutide in those with and without a history of myocardial infarction (MI) and/or stroke. Methods: LEADER was a randomized trial of liraglutide (1.8 mg or maximum tolerated dose) versus placebo in 9340 patients with type 2 diabetes mellitus and high cardiovascular risk, with a median follow-up of 3.8 years. The primary outcome was a composite of cardiovascular death, nonfatal MI, or nonfatal stroke (major adverse cardiovascular events). Risk groups in this post hoc analysis were defined by history of MI/stroke, established atherosclerotic cardiovascular disease without MI/stroke, or cardiovascular risk factors alone. Results: Of the 9340 patients, 3692 (39.5%) had a history of MI/stroke, 3083 (33.0%) had established atherosclerotic cardiovascular disease without MI/stroke, and 2565 (27.5%) had risk factors alone. Major adverse cardiovascular events occurred in 18.8% of patients with a history of MI/stroke (incidence rate, 5.0 per 100 patient-years), 11.6% of patients with established atherosclerotic cardiovascular disease without MI/stroke (incidence rate, 3.0 per 100 patient-years), and 9.8% of patients with cardiovascular risk factors alone (incidence rate, 2.6 per 100 patient-years). Liraglutide reduced major adverse cardiovascular events in patients with a history of MI/stroke (322 of 1865 [17.3%] versus 372 of 1827 patients [20.4%]; hazard ratio, 0.85; 95% CI, 0.73-0.99) and in those with established atherosclerotic cardiovascular disease without MI/stroke (158 of 1538 [10.3%] versus 199 of 1545 patients [12.9%]; hazard ratio, 0.76; 95% CI, 0.62-0.94) compared with placebo. In patients with risk factors alone, the hazard ratio for liraglutide versus placebo was 1.08 (95% CI, 0.84-1.38, Pinteraction=0.11). Similar results were seen for secondary outcomes across risk groups. Conclusions: In this post hoc analysis of patients with type 2 diabetes mellitus and high cardiovascular risk, liraglutide reduced cardiovascular outcomes both in patients with a history of MI/stroke and in those with established atherosclerotic cardiovascular disease without MI/stroke. The cardiovascular effect appeared neutral in patients with cardiovascular risk factors alone
Clinical Profiles, Outcomes, and Sex Differences of Patients With STEMI: Findings From the NORIN-STEMI Registry
Background: Low- and middle-income countries account for most of the global burden of coronary artery disease. There is a paucity of data regarding epidemiology and outcomes for ST-segment elevation myocardial infarction (STEMI) patients in these regions. Objectives: The authors studied the contemporary characteristics, practice patterns, outcomes, and sex differences in patients with STEMI in India. Methods: NORIN-STEMI (North India ST-Segment Elevation Myocardial Infarction Registry) is an investigator-initiated prospective cohort study of patients presenting with STEMI at tertiary medical centers in North India. Results: Of 3,635 participants, 16% were female patients, one-third were <50 years of age, 53% had a history of smoking, 29% hypertension, and 24% diabetes. The median time from symptom onset to coronary angiography was 71 hours; the majority (93%) presented first to a non-percutaneous coronary intervention (PCI)-capable facility. Almost all received aspirin, statin, P2Y12 inhibitors, and heparin on presentation; 66% were treated with PCI (98% femoral access) and 13% received fibrinolytics. The left ventricular ejection fraction was <40% in 46% of patients. The 30-day and 1-year mortality rates were 9% and 11%, respectively. Compared with male patients, female patients were less likely to receive PCI (62% vs 73%; P < 0.0001) and had a more than 2-fold greater 1-year mortality (22% vs 9%; adjusted HR: 2.1; 95% CI: 1.7-2.7; P <0.001). Conclusions: In this contemporary registry of patients with STEMI in India, female patients were less likely to receive PCI after STEMI and had a higher 1-year mortality compared with male patients. These findings have important public health implications, and further efforts are required to reduce these gaps
- …