594 research outputs found
When can we reconstruct the ancestral state? Beyond Brownian motion
Reconstructing the ancestral state of a group of species helps answer many
important questions in evolutionary biology. Therefore, it is crucial to
understand when we can estimate the ancestral state accurately. Previous works
provide a necessary and sufficient condition, called the big bang condition,
for the existence of an accurate reconstruction method under discrete trait
evolution models and the Brownian motion model. In this paper, we extend this
result to a wide range of continuous trait evolution models. In particular, we
consider a general setting where continuous traits evolve along the tree
according to stochastic processes that satisfy some regularity conditions. We
verify these conditions for popular continuous trait evolution models including
Ornstein-Uhlenbeck, reflected Brownian Motion, and Cox-Ingersoll-Ross
Simple Transferability Estimation for Regression Tasks
We consider transferability estimation, the problem of estimating how well
deep learning models transfer from a source to a target task. We focus on
regression tasks, which received little previous attention, and propose two
simple and computationally efficient approaches that estimate transferability
based on the negative regularized mean squared error of a linear regression
model. We prove novel theoretical results connecting our approaches to the
actual transferability of the optimal target models obtained from the transfer
learning process. Despite their simplicity, our approaches significantly
outperform existing state-of-the-art regression transferability estimators in
both accuracy and efficiency. On two large-scale keypoint regression
benchmarks, our approaches yield 12% to 36% better results on average while
being at least 27% faster than previous state-of-the-art methods.Comment: Paper published at The 39th Conference on Uncertainty in Artificial
Intelligence (UAI) 202
Acute Kidney Injury After Percutaneous Coronary Intervention Guided by Intravascular Ultrasound
Purpose We investigated the impact of intravascular ultrasound guidance on reducing the incidence of contrast-induced acute kidney injury (CI-AKI) in patients undergoing percutaneous coronary intervention (PCI). Methods Ninety-nine patients were enrolled in this prospective cohort who were not randomly assigned to angiography-guided percutaneous coronary intervention or intravascular ultrasound-guided percutaneous coronary intervention. The patients were hospitalized at the Vietnam National Heart Institute - Bach Mai Hospital between 2019 and 2020. Acute kidney injury incidence during hospitalization was the primary endpoint. Results A total of 99 patients were divided into two groups: the intravascular ultrasound-guided group (33 participants) and the angiography-guided group (66 participants). The mean ± SD contrast volume of each group was 95.2 ± 37.1 mL and 133.0 ± 36.0 mL for the ultrasound-guided and angiography-guided groups, with P \u3c 0.0001. Intravascular imaging-guided percutaneous coronary intervention (IVUS-guided PCI) was associated with reduced acute kidney injury incidence during hospitalization: 0.0% vs. 12.12% and P = 0.049. Conclusions Intravascular ultrasound is a safe imaging tool that guides percutaneous coronary intervention and significantly reduces the rate of acute kidney injury compared to angiography alone. Patients who have a high chance of experiencing acute kidney injury benefit from using intravascular ultrasound
FTKHUIM: A fast and efficient method for mining top-k high-utility itemsets
High-utility itemset mining (HUIM) is an important task in the field of knowledge data
discovery. The large search space and huge number of HUIs are the consequences of applying HUIM
algorithms with an inappropriate user-defined minimum utility threshold value. Determining a suitable
threshold value to obtain the expected results is not a simple task and requires spending a lot of time.
For common users, it is difficult to define a minimum threshold utility for exploring the right number of
HUIs. On the one hand, if the threshold is set too high then the number of HUIs would not be enough.
On the other hand, if the threshold is set too low, too many HUIs will be mined, thus wasting both time and
memory. The top-k HUIs mining problem was proposed to solve this issue, and many effective algorithms
have since been introduced by researchers. In this research, a novel approach, namely FTKHUIM (Fast top k HUI Mining), is introduced to explore the top-k HUIs. One new threshold-raising strategy called RTU,
a transaction utility (TU)-based threshold-raising strategy, has also been shown to rapidly increase the speed
of top-k HUIM. The study also proposes a global structure to store utility values in the process of applying
raising-threshold strategies to optimize these strategies. The results of experiments on various datasets prove
that the FTKHUIM algorithm achieves better results with regard to both the time and search space needed.Web of Science1110480510478
Mapping for engagement: setting up a community based participatory research project to reach underserved communities at risk for Hepatitis C in Ho Chi Minh City, Vietnam
Background: Approximately 1. 07 million people in Vietnam are infected with hepatitis C virus (HCV). To address this epidemic, the South East Asian Research Collaborative in Hepatitis (SEARCH) launched a 600-patient cohort study and two clinical trials, both investigating shortened treatment strategies for chronic HCV infection with direct-acting antiviral drugs. We conducted ethnographic research with a subset of trial participants and found that the majority were aware of HCV infection and its implications and were motivated to seek treatment. However, people who inject drugs (PWID), and other groups at risk for HCV were under-represented, although injecting drug use is associated with high rates of HCV. Material and Methods: We designed a community-based participatory research (CBPR) study to engage in dialogues surrounding HCV and other community-prioritized health issues with underserved groups at risk for HCV in Ho Chi Minh City. The project consists of three phases: situation analysis, CBPR implementation, and dissemination. In this paper, we describe the results of the first phase (i.e., the situation analysis) in which we conducted desk research and organized stakeholder mapping meetings with representatives from local non-government and community-based organizations where we used participatory research methods to identify and analyze key stakeholders working with underserved populations. Results: Twenty six institutions or groups working with the key underserved populations were identified. Insights about the challenges and dynamics of underserved communities were also gathered. Two working groups made up of representatives from the NGO and CBO level were formed. Discussion: Using the information provided by local key stakeholders to shape the project has helped us to build solid relationships, give the groups a sense of ownership from the early stages, and made the project more context specific. These steps are not only important preliminary steps for participatory studies but also for other research that takes place within the communities
Spin-Dependent Electronic Transport in IrMn–Co/Pd Multilayered Systems
Relation between magnetoresistance and magnetization reversal in thin multilayered IrMn-Co/Pd films deposited both on planar and nanoporous substrates is in focus of the present work. Magnetic anisotropy, exchange coupling and mechanisms of magnetic resistivity are discussed
Enhanced Perpendicular Exchange Bias in Co/Pd Antidot Arrays
Magnetic nanostructures revealing the exchange bias (EB) effect have attracted much interest in recent years due to their promising applications in spintronics, magnetic sensing and recording devices with various functionalities. In this paper, we report on the perpendicular exchange bias effect in a multilayered thin film composed of [Co/Pd] ferromagnetic multilayers exchange-coupled to an antiferromagnetic IrMn. The film was deposited on a porous anodized titania template. Influences of the films’ surface morphology as well as the order of layers deposited on the EB effect were studied. The enhancements of the EB field HEB (up to 30%) and the coercive field HC (two times) were achieved in the nanoporous films relative to their continuous film counterparts, which could be attributed to the specific morphology of the porous surfaces
Viral Etiology of Encephalitis in Children in Southern Vietnam: Results of a One-Year Prospective Descriptive Study
Viral encephalitis is associated with high morbidity and mortality in Vietnam. However little is known about the causes of the disease due to a lack of diagnostic facilities in this relatively resource-poor setting. Knowledge about the etiologies and clinical outcome of viral encephalitis is necessary for future design of intervention studies targeted at improvement of clinical management, treatment and prevention of the disease. We report the viral agents, clinical outcome and prognostic factors of mortality of encephalitis in children admitted to a referral hospital for children in southern Vietnam. We show that about one third of the enrolled patients die acutely, and that mortality is independently associated with patient age and Glasgow Coma Scale on admission. Japanese encephalitis, dengue virus and enterovirus (including enterovirus 71) are the major viruses detected in our patients. However, more than half of the patients remain undiagnosed, while mortality in this group is as high as in the diagnosed group. This study will benefit clinicians and public health in terms of clinical management and prevention of childhood encephalitis in Vietnam
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