4,690 research outputs found
Mining Frequent Itemsets over Uncertain Databases
In recent years, due to the wide applications of uncertain data, mining
frequent itemsets over uncertain databases has attracted much attention. In
uncertain databases, the support of an itemset is a random variable instead of
a fixed occurrence counting of this itemset. Thus, unlike the corresponding
problem in deterministic databases where the frequent itemset has a unique
definition, the frequent itemset under uncertain environments has two different
definitions so far. The first definition, referred as the expected
support-based frequent itemset, employs the expectation of the support of an
itemset to measure whether this itemset is frequent. The second definition,
referred as the probabilistic frequent itemset, uses the probability of the
support of an itemset to measure its frequency. Thus, existing work on mining
frequent itemsets over uncertain databases is divided into two different groups
and no study is conducted to comprehensively compare the two different
definitions. In addition, since no uniform experimental platform exists,
current solutions for the same definition even generate inconsistent results.
In this paper, we firstly aim to clarify the relationship between the two
different definitions. Through extensive experiments, we verify that the two
definitions have a tight connection and can be unified together when the size
of data is large enough. Secondly, we provide baseline implementations of eight
existing representative algorithms and test their performances with uniform
measures fairly. Finally, according to the fair tests over many different
benchmark data sets, we clarify several existing inconsistent conclusions and
discuss some new findings.Comment: VLDB201
Hierarchical Semi-Implicit Variational Inference with Application to Diffusion Model Acceleration
Semi-implicit variational inference (SIVI) has been introduced to expand the
analytical variational families by defining expressive semi-implicit
distributions in a hierarchical manner. However, the single-layer architecture
commonly used in current SIVI methods can be insufficient when the target
posterior has complicated structures. In this paper, we propose hierarchical
semi-implicit variational inference, called HSIVI, which generalizes SIVI to
allow more expressive multi-layer construction of semi-implicit distributions.
By introducing auxiliary distributions that interpolate between a simple base
distribution and the target distribution, the conditional layers can be trained
by progressively matching these auxiliary distributions one layer after
another. Moreover, given pre-trained score networks, HSIVI can be used to
accelerate the sampling process of diffusion models with the score matching
objective. We show that HSIVI significantly enhances the expressiveness of SIVI
on several Bayesian inference problems with complicated target distributions.
When used for diffusion model acceleration, we show that HSIVI can produce high
quality samples comparable to or better than the existing fast diffusion model
based samplers with a small number of function evaluations on various datasets.Comment: 25 pages, 13 figures, NeurIPS 202
Insulin resistance, autophagy and apoptosis in patients with polycystic ovary syndrome: Association with PI3K signaling pathway
Polycystic ovary syndrome (PCOS) is a disease in which endocrine metabolic abnormalities coexist with reproductive system abnormalities, with the main clinical manifestations including abnormal menstruation, hirsutism, acne, infertility, and obesity, and it is also a high risk for the development of many pregnancy complications, gynecological malignancies and other diseases. Therefore, timely intervention to prevent the progression of PCOS is of great significance for improving the quality of life of most female patients. Insulin resistance (IR) is one of the most common endocrine disorders in PCOS patients, with approximately 75% of PCOS patients experiencing varying degrees of IR. It is now believed that it is mainly related to the PI3K signaling pathway. The role of autophagy and apoptosis of ovarian granulosa cells (GCs) in the pathogenesis of PCOS has also been gradually verified in recent years. Coincidentally, it also seems to be associated with the PI3K signaling pathway. Our aim is to review these relevant studies, to explore the association between the IR, cellular autophagy and apoptosis in PCOS patients and the PI3K pathway. We summarize some of the drug studies that have improved PCOS as well. We have also found that proteomics holds great promise in exploring the pathogenesis of PCOS, and we have published our views on this
Angiogenesis and Vasculogenesis at 7-Day of Reperfused Acute Myocardial Infarction
Objectives 
This study is to investigate the angiogenesis and vasculogenesis at the first week of reperfused acute myocardial infarction (AMI).
Methods 
16 of mini-swines (20 to 30 Kg) were randomly assigned to the sham-operated group and the AMI group. The acute myocardial infarction and reperfusion model was created and the pig tail catheter was performed to monitor hemodynamics before left anterior descending coronary artery (LAD) occlusion, 90 min of LAD occlusion and 120 min of LAD reperfusion. Pathologic myocardial tissue was collected at 7-day of LAD reperfusion and further assessed by immunochemistry, dual immunochemistry, in-situ hybridization, real-time quantitative polymerase chain reaction and western blot. 
Results 
The infarcted area had higher FLK1 mRNA expression than sham-operated area and the normal area (all P<0.05), and the infarcted and marginal areas showed higher CD146 protein expression than the sham-operated area (all P<0.05), but the microvessel density (CD31 positive expression of microvessels/HP) was not significantly different between the infarcted area and the sham-operated area (8.92±3.05 vs 6.43±1.54) at 7-day of reperfused acute myocardial infarction (P>0.05). 
Conclusions 
FLK1 and CD146 expression significantly increase in the infarcted and marginal areas, and the microvessel density is not significantly different between the infarcted area and the sham-operated area, suggesting that angiogenesis and vasculogenesis in the infarcted area appear to high frequency of increase in 7-day of reperfused myocardial infarction. 

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