433 research outputs found
Slice-level Detection of Intracranial Hemorrhage on CT Using Deep Descriptors of Adjacent Slices
The rapid development in representation learning techniques such as deep
neural networks and the availability of large-scale, well-annotated medical
imaging datasets have to a rapid increase in the use of supervised machine
learning in the 3D medical image analysis and diagnosis. In particular, deep
convolutional neural networks (D-CNNs) have been key players and were adopted
by the medical imaging community to assist clinicians and medical experts in
disease diagnosis and treatment. However, training and inferencing deep neural
networks such as D-CNN on high-resolution 3D volumes of Computed Tomography
(CT) scans for diagnostic tasks pose formidable computational challenges. This
challenge raises the need of developing deep learning-based approaches that are
robust in learning representations in 2D images, instead 3D scans. In this
work, we propose for the first time a new strategy to train \emph{slice-level}
classifiers on CT scans based on the descriptors of the adjacent slices along
the axis. In particular, each of which is extracted through a convolutional
neural network (CNN). This method is applicable to CT datasets with per-slice
labels such as the RSNA Intracranial Hemorrhage (ICH) dataset, which aims to
predict the presence of ICH and classify it into 5 different sub-types. We
obtain a single model in the top 4% best-performing solutions of the RSNA ICH
challenge, where model ensembles are allowed. Experiments also show that the
proposed method significantly outperforms the baseline model on CQ500. The
proposed method is general and can be applied to other 3D medical diagnosis
tasks such as MRI imaging. To encourage new advances in the field, we will make
our codes and pre-trained model available upon acceptance of the paper.Comment: Accepted for presentation at the 22nd IEEE Statistical Signal
Processing (SSP) worksho
Marine Plastic Drift from the Mekong River to Southeast Asia
Southeast Asia is the world’s most polluted area in terms of marine plastics. The Mekong River is one of the largest rivers in the area, and ranked as somewhere between the 8th- and 11th-biggest contributor to plastics in the world’s oceans. Here, we investigate how microplastics drift from the Mekong river to Southeast Asia, and which coastlines are most exposed. We identify potential factors (wind drift, rivers, vertical mixing and sinking rates) that affect plastic drift in the region using the OpenDrift model with realistic wind and ocean currents for simulations between three months (summer and winter) and 15 months. We find that the seasonal drift is influenced by the monsoon systems and that most of the plastics strand in the Philippines and Indonesia. In addition, the role of wind drift is significant in strong winds. Vertical mixing and sinking rates are unknowns that affect the relative importance of wind drift (near the surface) and ocean currents. Simulations with different terminal velocities show that, unsurprisingly, the higher the terminal velocities are, the closer they deposit to the source. In light of the large uncertainties in sinking rates, we find that the plastic distribution has large uncertainties, but is clearly seasonal and influenced by wind, vertical mixing, river discharge and sinking rates. The Philippines and Indonesia are found to have the coastlines that are most exposed to plastic pollution from the Mekong river. This study shows that simulations of marine plastic drift are very variable, depending on many factors and assumptions. However, it provides more detailed information on marine plastic pollution in Southeast Asia, and hopefully helps authorities take more practical actions.publishedVersio
Last Round Convergence and No-Instant Regret in Repeated Games with Asymmetric Information
This paper considers repeated games in which one player has more information
about the game than the other players. In particular, we investigate repeated
two-player zero-sum games where only the column player knows the payoff matrix
A of the game. Suppose that while repeatedly playing this game, the row player
chooses her strategy at each round by using a no-regret algorithm to minimize
her (pseudo) regret. We develop a no-instant-regret algorithm for the column
player to exhibit last round convergence to a minimax equilibrium. We show that
our algorithm is efficient against a large set of popular no-regret algorithms
of the row player, including the multiplicative weight update algorithm, the
online mirror descent method/follow-the-regularized-leader, the linear
multiplicative weight update algorithm, and the optimistic multiplicative
weight update
Petrographic Characteristics and Depositional Environment Evolution of Middle Miocene Sediments in the Thien Ung - Mang Cau Structure of Nam Con Son Basin
This paper introduces the petrographic characteristics and depositional environment of Middle Miocene rocks of the Thien Ung - Mang Cau structure in the central area of Nam Con Son Basin based on the results of analyzing thin sections and structural characteristics of core samples. Middle Miocene sedimentary rocks in the studied area can be divided into three groups: (1) Group of terrigenous rocks comprising greywacke sandstone, arkosic sandstone, lithic-quartz sandstone, greywacke-lithic sandstone, oligomictic siltstone, and bitumenous claystone; (2) Group of carbonate rocks comprising dolomitic limestone and bituminous limestone; (3) Mixed group comprising calcareous sandstone, calcarinate sandstone, arenaceous limestone, calcareous claystone, calcareous silty claystone, dolomitic limestone containing silt, and bitumen. The depositional environment is expressed through petrographic characteristics and structure of the sedimentary rocks in core samples. The greywacke and arkosic sandstones are of medium grain size, poor sorting and roundness, and siliceous cement characterizing the alluvial and estuarine fan environment expressed by massive structure of core samples. The mixed calcareous limestone, arenaceous dolomitic limestone, and calcareous and bituminous clayey siltstone in the core samples are of turbulent flow structure characterizing shallow bay environment with the action of bottom currents. The dolomitic limestones are of relatively homogeneous, of microgranular and fine-granular texture, precipitated in a weakly reducing, semi-closed, and relatively calm bay environment
No Exchange of Picornaviruses in Vietnam between Humans and Animals in a High-Risk Cohort with Close Contact despite High Prevalence and Diversity
Hospital-based and community-based ‘high-risk cohort’ studies investigating humans at risk of zoonotic infection due to occupational or residential exposure to animals were conducted in Vietnam, with diverse viruses identified from faecal samples collected from humans, domestic and wild animals. In this study, we focus on the positive-sense RNA virus family Picornaviridae, investigating the prevalence, diversity, and potential for cross-species transmission. Through metagenomic sequencing, we found picornavirus contigs in 23% of samples, belonging to 15 picornavirus genera. Prevalence was highest in bats (67%) while diversity was highest in rats (nine genera). In addition, 22% of the contigs were derived from novel viruses: Twelve phylogenetically distinct clusters were observed in rats of which seven belong to novel species or types in the genera Hunnivirus, Parechovirus, Cardiovirus, Mosavirus and Mupivirus; four distinct clusters were found in bats, belonging to one novel parechovirus species and one related to an unclassified picornavirus. There was no evidence for zoonotic transmission in our data. Our study provides an improved knowledge of the diversity and prevalence of picornaviruses, including a variety of novel picornaviruses in rats and bats. We highlight the importance of monitoring the human–animal interface for possible spill-over events
Consequences of infertility in developing countries: results of a questionnaire and interview survey in the South of Vietnam
BACKGROUND: This study explores the psychological, socio-cultural and economic consequences of infertility on couples' life. The purpose of this research is to improve knowledge about the potentially serious implications of infertility in the South of Vietnam. METHODS: This study included 118 infertile couples who filled in questionnaires and 28 men and women who were interviewed. RESULTS: Data of the questionnaire show men and women do not differ in their responses and attitudes towards infertility. Almost one-third of the participants require psychological support. Interviewees experience secrecy, social pressure and economic hardship. CONCLUSION: Offspring are very important to Vietnamese couples. Their future depends on children. Family plays an important role in the experiences of the infertile couple. Economic consequences are a particular distressing factor. There is a need for psychological counselling in the treatment of infertile couples in the South of Vietnam. It should be realised that in developing countries, despite overpopulation, unwanted childlessness is an important social and economical burden that needs attention
Gaussian density estimates for the solution of singular stochastic Riccati equations
summary:Stochastic Riccati equation is a backward stochastic differential equation with singular generator which arises naturally in the study of stochastic linear-quadratic optimal control problems. In this paper, we obtain Gaussian density estimates for the solutions to this equation
Intensified Antituberculosis Therapy in Adults with Tuberculous Meningitis
BACKGROUND
Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients.
METHODS
We performed a randomized, double-blind, placebo-controlled trial involving human immunodeficiency virus (HIV)-infected adults and HIV-uninfected adults with a clinical diagnosis of tuberculous meningitis who were admitted to one of two Vietnamese hospitals. We compared a standard, 9-month antituberculosis regimen (which included 10 mg of rifampin per kilogram of body weight per day) with an intensified regimen that included higher-dose rifampin (15 mg per kilogram per day) and levofloxacin (20 mg per kilogram per day) for the first 8 weeks of treatment. The primary outcome was death by 9 months after randomization.
RESULTS
A total of 817 patients (349 of whom were HIV-infected) were enrolled; 409 were randomly assigned to receive the standard regimen, and 408 were assigned to receive intensified treatment. During the 9 months of follow-up, 113 patients in the intensified-treatment group and 114 patients in the standard-treatment group died (hazard ratio, 0.94; 95% confidence interval, 0.73 to 1.22; P=0.66). There was no evidence of a significant differential effect of intensified treatment in the overall population or in any of the subgroups, with the possible exception of patients infected with isoniazid-resistant M. tuberculosis. There were also no significant differences in secondary outcomes between the treatment groups. The overall number of adverse events leading to treatment interruption did not differ significantly between the treatment groups (64 events in the standard-treatment group and 95 events in the intensified-treatment group, P=0.08).
CONCLUSIONS
Intensified antituberculosis treatment was not associated with a higher rate of survival among patients with tuberculous meningitis than standard treatment. (Funded by the Wellcome Trust and the Li Ka Shing Foundation; Current Controlled Trials number, ISRCTN61649292.)
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