614 research outputs found
Deterministic walks in random networks: an application to thesaurus graphs
In a landscape composed of N randomly distributed sites in Euclidean space, a
walker (``tourist'') goes to the nearest one that has not been visited in the
last \tau steps. This procedure leads to trajectories composed of a transient
part and a final cyclic attractor of period p. The tourist walk presents
universal aspects with respect to \tau and can be done in a wide range of
networks that can be viewed as ordinal neighborhood graphs. As an example, we
show that graphs defined by thesaurus dictionaries share some of the
statistical properties of low dimensional (d=2) Euclidean graphs and are easily
distinguished from random graphs. This approach furnishes complementary
information to the usual clustering coefficient and mean minimum separation
length.Comment: 12 pages, 5 figures, revised version submited to Physica A, corrected
references to figure
Efficacy and Safety of Alirocumab 150 mg Every 4 Weeks in Patients With Hypercholesterolemia Not on Statin Therapy: The ODYSSEY CHOICE II Study
Background - The PCSK9 antibody alirocumab (75 mg every 2 weeks; Q2W) as monotherapy reduced low-density lipoprotein-cholesterol (LDL-C) levels by 47%. Because the option of a monthly dosing regimen is convenient, ODYSSEY CHOICE II evaluated alirocumab 150 mg Q4W in patients with inadequately controlled hypercholesterolemia and not on statin (majority with statin-associated muscle symptoms), receiving treatment with fenofibrate, ezetimibe, or diet alone.
Methods and Results - Patients were randomly assigned to placebo, alirocumab 150 mg Q4W or 75 mg Q2W (calibrator arm), with dose adjustment to 150 mg Q2W at week (W) 12 if W8 predefined LDL-C target levels were not met. The primary efficacy endpoint was LDL-C percentage change from baseline to W24. Mean baseline LDL-C levels were 163.9 mg/dL (alirocumab 150 mg Q4W, n= 59), 154.5 mg/dL (alirocumab 75 mg Q2W, n= 116), and 158.5 mg/dL (placebo, n= 58). In the alirocumab 150 mg Q4W and 75 mg Q2W groups (49.1% and 36.0% of patients received dose adjustment, respectively), least-squares mean LDL-C changes from baseline to W24 were -51.7% and -53.5%, respectively (placebo [+ 4.7%]; both groups P< 0.0001 versus placebo). In total, 63.9% and 70.3% of alirocumab-treated patients achieved their LDL-C targets at W24. Treatment-emergent adverse events occurred in 77.6% (alirocumab 150 mg Q4W), 73.0% (alirocumab 75 mg Q2W), and 63.8% (placebo) of patients, with injection-site reactions among the most common treatment-emergent adverse events.
Conclusions - Alirocumab 150 mg Q4W can be considered in patients not on statin with inadequately controlled hypercholesterolemia as a convenient option for lowering LDL-C
Why social networks are different from other types of networks
We argue that social networks differ from most other types of networks,
including technological and biological networks, in two important ways. First,
they have non-trivial clustering or network transitivity, and second, they show
positive correlations, also called assortative mixing, between the degrees of
adjacent vertices. Social networks are often divided into groups or
communities, and it has recently been suggested that this division could
account for the observed clustering. We demonstrate that group structure in
networks can also account for degree correlations. We show using a simple model
that we should expect assortative mixing in such networks whenever there is
variation in the sizes of the groups and that the predicted level of
assortative mixing compares well with that observed in real-world networks.Comment: 9 pages, 2 figure
Self-avoiding walks and connective constants in small-world networks
Long-distance characteristics of small-world networks have been studied by
means of self-avoiding walks (SAW's). We consider networks generated by
rewiring links in one- and two-dimensional regular lattices. The number of
SAW's was obtained from numerical simulations as a function of the number
of steps on the considered networks. The so-called connective constant,
, which characterizes the long-distance
behavior of the walks, increases continuously with disorder strength (or
rewiring probability, ). For small , one has a linear relation , and being constants dependent on the underlying
lattice. Close to one finds the behavior expected for random graphs. An
analytical approach is given to account for the results derived from numerical
simulations. Both methods yield results agreeing with each other for small ,
and differ for close to 1, because of the different connectivity
distributions resulting in both cases.Comment: 7 pages, 5 figure
Association of serum lipoprotein (a) with the requirement for a peripheral artery operation and the incidence of major adverse cardiovascular events in people with peripheral artery disease
Background: The aim of this study was to assess the relationship between serum lipoprotein (a) (Lp[a]) concentration and the requirement for peripheral artery disease (PAD) operations or incidence of major adverse cardiovascular events. Methods and Results: A total of 1472 people with PAD presenting with intermittent claudication (n=355), abdominal aortic aneurysm (n=989) or critical limb ischemia (n=128) were prospectively recruited from 4 outpatient clinics in Australia. Lp(a) was measured in serum samples collected at recruitment using an immunoassay. Participants were followed for a median (interquartile range) of 2.4 (0.1â6.1) years to record requirement for any PAD operation, defined to include any open or endovascular PAD intervention (lower limb peripheral revascularization, abdominal aortic aneurysm repair, other aneurysm repair, or carotid artery revascularization). Myocardial infarctions, strokes, and deaths were also recorded. The association of Lp(a) with events was assessed using Cox proportional hazard analysis adjusting for traditional risk factors. Participants with Lp(a) â„30 mg/dL had a greater requirement for any PAD operation (hazard ratio, 1.20, 95% CI, 1.02â1.41) and lower limb peripheral revascularization alone (hazard ratio 1.33, 95% CI, 1.06â1.66) but no increased risk of major adverse cardiovascular events or allâcause mortality. Lp(a) â„50 mg/dL and a 40 mg/dL increase in Lp(a) were also associated with an increased risk of lower limb peripheral revascularization alone but not with other outcomes. Conclusions: In participants with PAD referred for hospital management those with high Lp(a) had greater requirement for lower limb peripheral revascularization but Lp(a) was not consistently associated with other clinical events.Jonathan Golledge, Sophie Rowbotham, Ramesh Velu, Frank Quigley, Jason Jenkins ... Shivshankar Thanigaimani ... et al
Toward an international consensus-Integrating lipoprotein apheresis and new lipid-lowering drugs
Background: Despite advances in pharmacotherapy of lipid disorders, many dyslipidemic patients do not attain sufficient lipid lowering to mitigate risk of atherosclerotic cardiovascular disease. Several classes of novel lipid-lowering agents are being evaluated to reduce atherosclerotic cardiovascular disease risk. Lipoprotein apheresis (LA) is effective in acutely lowering the plasma concentrations of atherogenic lipoproteins including low-density lipoprotein cholesterol and lipoprotein(a), and novel lipid-lowering drugs may dampen the lipid rebound effect of LA, with the possibility that LA frequency may be decreased, in some cases even be discontinued. Sources of material: This document builds on current American Society for Apheresis guidelines and, for the first time, makes recommendations from summarized data of the emerging lipid-lowering drug classes (inhibitors of proprotein convertase subtilisin/kexin type 9 or microsomal triglyceride transfer protein, high-density lipoprotein mimetic), including the available evidence on combination therapy with LA with respect to the management of patients with dyslipidemia. Abstract of findings: Recommendations for different indications are given based on the latest evidence. However, except for lomitapide in homozygous familial hypercholesterolemia and alirocumab/evolocumab in heterozygous familial hypercholesterolemia subjects, limited data are available on the effectiveness and safety of combination therapy. More studies on combining LA with novel lipid-lowering drugs are needed. Conclusion: Novel lipid-lowering agents have potential to improve the performance of LA, but more evidence is needed. The Multidisciplinary International Group for Hemapheresis TherapY and Metabolic DIsturbances Contrast scientific society aims to establish an international registry of clinical experience on LA combination therapy to expand the evidence on this treatment in individuals at high cardiovascular disease risk
Efficacy of Statin Therapy in Pulmonary Arterial Hypertension : a Systematic Review and Meta-Analysis
Since the evidence regarding statin therapy in PAH has not been conclusive, we assessed the impact of statin therapy in PAH through a systematic review and meta-analysis of available studies. We searched selected databases up to August 1, 2015 to identify the studies investigating the effect of statin administration on PAH. Meta-analysis was performed using either a fixed-effects or random-effect model according to I 2 statistic. Meta-analysis of 8 studies with 665 patients did not suggest any significant improvement in 6-min walking distance (6MWD) by statin therapy (weighed mean difference [WMD]:-6.08 m, 95% confidence interval [CI]:-25.66, 13.50, p = 0.543; Q = 8.41, I 2 = 28.64%). Likewise, none of the other indices including pulmonary arterial pressure (WMD:-0.97 mmHg, 95%CI:-4.39, 2.44, p = 0.577; Q = 14.64, I 2 = 79.51%), right atrial pressure (WMD: 1.01 mmHg, 95%CI:-0.93, 2.96, p = 0.307; Q = 44.88, I2 = 95.54%), cardiac index (WMD: 0.05 L/min/m2, 95%CI:-0.05, 0.15, p = 0.323; Q = 3.82, I 2 = 21.42%), and pulmonary vascular resistance (WMD:-1.42 dyn 17s/cm5, 95%CI:-72.11, 69.27, p = 0.969; Q = 0.69, I2 = 0%) was significantly altered by statin therapy. In conclusion, the results of the meta-analysis did not show a statistically significant effect of statin therapy in the improvement of 6MWD, pulmonary arterial pressure, right atrial pressure, cardiac index and pulmonary vascular resistance
Quantifying atherogenic lipoproteins for lipid-lowering strategies : Consensus-based recommendations from EAS and EFLM
The joint consensus panel of the European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently addressed present and future challenges in the laboratory diagnostics of atherogenic lipoproteins. Total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, and calculated non-HDL cholesterol (= total - HDL cholesterol) constitute the primary lipid panel for estimating risk of atherosclerotic cardiovascular disease (ASCVD) and can be measured in the nonfasting state. LDL cholesterol is the primary target of lipid-lowering therapies. For on-treatment follow-up, LDL cholesterol shall be measured or calculated by the same method to attenuate errors in treatment decisions due to marked between-method variations. Lipoprotein(a)-cholesterol is part of measured or calculated LDL cholesterol and should be estimated at least once in all patients at risk of ASCVD, especially in those whose LDL cholesterol decline poorly upon statin treatment. Residual risk of ASCVD even under optimal LDL-lowering treatment should be also assessed by non-HDL cholesterol or apolipoprotein B, especially in patients with mild-to-moderate hypertriglyceridemia (2-10 mmol/L). Non-HDL cholesterol includes the assessment of remnant lipoprotein cholesterol and shall be reported in all standard lipid panels. Additional apolipoprotein B measurement can detect elevated LDL particle numbers often unidentified on the basis of LDL cholesterol alone. Reference intervals of lipids, lipoproteins, and apolipoproteins are reported for European men and women aged 20-100 years. However, laboratories shall flag abnormal lipid values with reference to therapeutic decision thresholds.Peer reviewe
Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS
We present the results of a search for new, heavy particles that decay at a
significant distance from their production point into a final state containing
charged hadrons in association with a high-momentum muon. The search is
conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV
and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS
detector operating at the Large Hadron Collider. Production of such particles
is expected in various scenarios of physics beyond the standard model. We
observe no signal and place limits on the production cross-section of
supersymmetric particles in an R-parity-violating scenario as a function of the
neutralino lifetime. Limits are presented for different squark and neutralino
masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final
version to appear in Physics Letters
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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