3,065 research outputs found
Streaming, Distributed Variational Inference for Bayesian Nonparametrics
This paper presents a methodology for creating streaming, distributed
inference algorithms for Bayesian nonparametric (BNP) models. In the proposed
framework, processing nodes receive a sequence of data minibatches, compute a
variational posterior for each, and make asynchronous streaming updates to a
central model. In contrast to previous algorithms, the proposed framework is
truly streaming, distributed, asynchronous, learning-rate-free, and
truncation-free. The key challenge in developing the framework, arising from
the fact that BNP models do not impose an inherent ordering on their
components, is finding the correspondence between minibatch and central BNP
posterior components before performing each update. To address this, the paper
develops a combinatorial optimization problem over component correspondences,
and provides an efficient solution technique. The paper concludes with an
application of the methodology to the DP mixture model, with experimental
results demonstrating its practical scalability and performance.Comment: This paper was presented at NIPS 2015. Please use the following
BibTeX citation: @inproceedings{Campbell15_NIPS, Author = {Trevor Campbell
and Julian Straub and John W. {Fisher III} and Jonathan P. How}, Title =
{Streaming, Distributed Variational Inference for Bayesian Nonparametrics},
Booktitle = {Advances in Neural Information Processing Systems (NIPS)}, Year
= {2015}
Oviposition Model for Timing Insecticide Sprays Against Plum Curculio (Coleoptera: Curculionidae) in New York State
Plum curculio, Conotrachelus nenuphar (Herbst), feeding and oviposition on apples during spring was measured for 3 yr in a heavily infested orchard in New York State. A logistic model was formulated to relate cumulative fruit injury to cumulative heat units (degree-days base 10°C [DD10]) following petal fall. Cumulative plum curculio injury was well described by the model in the trees from which data for the model were collected. However, injury progressed faster and ended earlier in smaller trees at the same site and at a different site, probably because of differences in tree architecture. Field trials showed that protection of the fruit via insecticide residue was no longer necessary after the model predicted that 40% of the cumulative plum curculio oviposition and feeding cycle had been completed (171 DD10 after petal fall). Based on historical weather records, use of the model to schedule insecticide treatments would save 1 insecticide application nearly half the time compared with a standard of 3 insecticide applications. A delay between initial plum curculio feeding and oviposition, which coincides with the petal fall, phenophase, and steadily increasing damage, which is influenced by temperatures after petal fall was observed. The effectiveness of delaying insecticide treatments until the rate of plum curculio damage was rapidly increasing was compared with treatments applied at petal fall. Delaying the 1st insecticide application resulted in higher levels of damage compared with making the 1st treatment immediately after petal fal
Does exercise-induced myocardial ischaemia cause enhanced platelet activation and fibrin formation in patients with stable angina and severe coronary artery disease?
In this study, betathromboglobulin (BTG) and fibrinopeptide A (FPA) in peripheral venous blood were measured in 20 patients with stable angina pectoris before and immediately after exercise-induced myocardial ischaemia; in 5 of the 20 patients stable angina was associated with typical peripheral artery disease. A total of 10 patients with angiographically documented peripheral artery disease without angina and 10 normal volunteers were taken as control groups. BTG and FPA in the 15 patients with stable angina before exercise were 41±14 ng ml-1 and 2.3±09 ng ml-1 and were not statistically different from the values in normal controls; after exercise-induced myocardial ischaemia no significant increase occurred in these patients. Conversely, in the 5 patients with stable angina associated with peripheral artery disease BTG and FPA before exercise were 6l±10 ng ml-1 and 3.5±0.8 ng ml-1 and increased to 114±14 ng ml-1 (P<0.001) and 4.l±0.5 ng ml-1 (P<0.01): These results were similar to those found in the 10 patients with isolated peripheral artery disease. We conclude that BTG and FPA in peripheral venous blood in patients with stable angina are not elevated either at rest or after exercise-induced myocardial ischaemia. Elevated values of BTG and FPA in patients with stable angina may reflect a major interaction between blood and atherosclerotic vessel wall, suggesting the presence of associated atherosclerotic lesions in peripheral artery diseas
Relation of Gallbladder Motility to Viscosity and Composition of Gallbladder Bile in Patients with Cholesterol Gallstones
Background/Aims: Increased viscosity and supersaturation of cholesterol in gallbladder bile, as well as an impaired motility of the gallbladder, are considered to be important factors in the pathogenesis of cholesterol gallstones. However, the relation of these parameters has not yet been determined. Material and Methods: Bile viscosity (mPa.s) was measured by rotation viscosimetry and the composition of gallbladder bile was determined using standard methodology. Gallbladder motility was calculated as ejection fraction in percent of total volume 45 min after a test meal using ultrasonography in patients with gallstones prior to elective cholecystectomy. Results: The study included 35 patients with cholesterol gallstones. Viscosity of gallbladder bile ranged between 0.9 and 12.5 mPa.s (median 2.2 mPa.s) and an ejection fraction of the gallbladder of 55.4 +/- 18.3% (mean +/- SD) was determined. No significant correlation (r = 0.19, p < 0.2) between the 2 parameters could be calculated. Analysis of the composition of gallbladder bile revealed a positive correlation of all components to biliary viscosity but not to the motility of the gallbladder, with the exceptions of a negative correlation (r = 0.39, p < 0.02) between mucin concentration and the ejection fraction at 45 min after the test meal. Conclusions: The motility of the gallbladder appears to be unrelated to the viscosity of gallbladder bile or gallbladder bile composition. The negative correlation between the ejection fraction of the gallbladder and mucin concentration of gallbladder bile suggests that chronic inflammation of the gallbladder wall is associated with both an impaired motility of the gallbladder and increased mucin release into gallbladder bile. Copyright (C) 2009 S. Karger AG, Base
Fibrin formation and platelet activation in patients with myocardial infarction and normal coronary arteries
Coronary spasm is the mechanism most often postulated to explain the rare combination of myocardial infarction and angiographically normal coronary arteries, although the reported evidence for its role is circumstantial rather than conclusive. Whereas the importance of thrombosis in myocardial infarction is uncontested in the presence of significant coronary artery disease, there is little in vivo evidence for thrombosis in angiographically normal coronary arteries. Among 11 consecutive patients with acute myocardial infarction undergoing thrombolytic therapy with recombinant tissue plasminogen activator (rtPA) 3.2 ± 0.7h after onset of chest pain, and angiography 10.2 ± 4.5 days later, three young men had normal coronary arteries. Their cases are documented electrocadiographically, enzymatically and angiographically. Mean plasma levels of fibrinopeptide A (FPA) and beta-thromboglobulin (BTG) were clearly elevated before and during rtPA therapy: FPA 52 ± 41 ng ml-1, BTG 257 ± 46 ng ml-1. They did not differ significantly from corresponding mean plasma levels in the eight patients with severe coronary artery disease: FPA 67 ± 66 ng ml-1, BTG 181 ± 75 ng ml-1. We conclude that fibrin formation and platelet activation are probably equally important in the early hours of myocardial infarction, whether or not significant coronary artery disease is presen
Multisystem proteinopathy due to a homozygous p.Arg159His VCP mutation : a tale of the unexpected
ObjectiveTo assess the clinical, radiologic, myopathologic, and proteomic findings in a patient manifesting a multisystem proteinopathy due to a homozygous valosin-containing protein gene (VCP) mutation previously reported to be pathogenic in the heterozygous state.MethodsWe studied a 36-year-old male index patient and his father, both presenting with progressive limb-girdle weakness. Muscle involvement was assessed by MRI and muscle biopsies. We performed whole-exome sequencing and Sanger sequencing for segregation analysis of the identified p.Arg159His VCP mutation. To dissect biological disease signatures, we applied state-of-the-art quantitative proteomics on muscle tissue of the index case, his father, 3 additional patients with VCP-related myopathy, and 3 control individuals.ResultsThe index patient, homozygous for the known p.Arg159His mutation in VCP, manifested a typical VCP-related myopathy phenotype, although with a markedly high creatine kinase value and a relatively early disease onset, and Paget disease of bone. The father exhibited a myopathy phenotype and discrete parkinsonism, and multiple deceased family members on the maternal side of the pedigree displayed a dementia, parkinsonism, or myopathy phenotype. Bioinformatic analysis of quantitative proteomic data revealed the degenerative nature of the disease, with evidence suggesting selective failure of muscle regeneration and stress granule dyshomeostasis.ConclusionWe report a patient showing a multisystem proteinopathy due to a homozygous VCP mutation. The patient manifests a severe phenotype, yet fundamental disease characteristics are preserved. Proteomic findings provide further insights into VCP-related pathomechanisms
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