320 research outputs found
Accurate formation energies of charged defects in solids: a systematic approach
Defects on surfaces of semiconductors have a strong effect on their
reactivity and catalytic properties. The concentration of different charge
states of defects is determined by their formation energies. First-principles
calculations are an important tool for computing defect formation energies and
for studying the microscopic environment of the defect. The main problem
associated with the widely used supercell method in these calculations is the
error in the electrostatic energy, which is especially pronounced in
calculations that involve surface slabs and 2D materials. We present an
internally consistent approach for calculating defect formation energies in
inhomogeneous and anisotropic dielectric environments, and demonstrate its
applicability to the cases of the positively charged Cl vacancy on the NaCl
(100) surface and the negatively charged S vacancy in monolayer MoS2
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Reasoning with Streamed Uncertain Information from Unreliable Sources
Humans or intelligent software agents are increasingly faced with the challenge of making decisions based on large volumes of streaming information from diverse sources. Decision makers must process the observed information by inferring additional information, estimating its reliability, and orienting it for decision making. Processing streaming trust framework, when fact is getting created and inferred is a process in online mode and our paper works effciently in online mode. In online mode, someone initiates a query and gets an output based on the query. In this paper we have mainly shown that unstructured reports from unreliable and heterogeneous sources are processed to generate structured information in Controlled English. Uncertainty in the information is modelled using Subjective Logic that allows statistical inference over uncertain information. Trustworthiness of information is modelled and conflicts are resolved before fusion. This process is totally undertaken on streaming information resulting in new facts being inferred from incoming information which immediately goes through trust assessment framework and trust is propagated to the inferred fact. In this paper, we propose a comprehensive framework where unstructured reports are streamed from heterogeneous and potentially untrustworthy information sources. These reports are processed to extract valuable uncertain information, which is represented using Controlled Natural Language
and Subjective Logic. Additional information is inferred using deduction and abduction operations over subjective opinions derived from the reports. Before fusing extracted and inferred opinions, the framework estimates trustworthiness of these opinions, detects conflicts between them, and resolve these conflicts by analysing evidence about the reliability of their sources. Lastly, we describe an implementation of the framework using International Technology Alliance (ITA) assets (Information Fabric Services and Controlled English Fact Store) and present an experimental evaluation that quantifies the efficiency with respect to accuracy and overhead of the proposed framework
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Location attestation and access control for mobile devices using GeoXACML
Access control has been applied in various scenarios in the past for negotiating the best policy. Solutions with XACML for access control has been very well explored by research and have resulted in significant contributions to various sectors including healthcare. In controlling access to the sensitive data such as medical records, it is important to guarantee that the data is accessed by the right person for the right reason. Location of access requestor can be a good indication for his/her eligibility and reasons for accessing the data. To reason with geospatial information for access control, Geospatial XACML (eXtensible Access Control Markup Language) is proposed as a standard. However, there is no available implementation and architecture for reasoning with Geospatial XACML policies. This paper proposes to extend XACML with geohashing to implement geospatial policies. It also proposes an architecture for checking reliability of the geospatial information provided by clients. With a case study, we demonstrate how our framework can be used to control the privacy and data access of health service data in handheld devices
Misclassification Risk and Uncertainty Quantification in Deep Classifiers
In this paper, we propose risk-calibrated evidential deep classifiers to reduce the costs associated with classification errors. We use two main approaches. The first is to develop methods to quantify the uncertainty of a classifier’s predictions and reduce the likelihood of acting on erroneous predictions. The second is a novel way to train the classifier such that erroneous classifications are biased towards less risky categories. We combine these two approaches in a principled way. While doing this, we extend evidential deep learning with pignistic probabilities, which are used to quantify uncertainty of classification predictions and model rational decision making under uncertainty.We evaluate the performance of our approach on several image classification tasks. We demonstrate that our approach allows to (i) incorporate misclassification cost while training deep classifiers, (ii) accurately quantify the uncertainty of classification predictions, and (iii) simultaneously learn how to make classification decisions to minimize expected cost of classification errors
Cancer in Youth Living With HIV (YLWHIV): A narrative review of the access to oncological services among YLWHIV and the role of economic strengthening in child health
Youth Living with HIV/AIDS (YLWHIV) have a higher risk of developing immunodeficiency related illnesses including certain cancers than their general population counterparts of the same age. This narrative review of current available literature describes factors associated with pediatric access to oncological services, and the role economic strengthening could play in improving health outcomes for this vulnerable population. Findings suggest that both HIV-infected and -uninfected children living in low and middle-income countries struggle with access and adherence to cancer treatment and care. Cost of treatment is a major barrier to access and adherence. Asset-building savings programs may increase financial security and subsequently result in better health outcomes although they have not been utilized to improve access to cancer treatment
Analysis of cross-correlations between financial markets after the 2008 crisis
We analyze the cross-correlation matrix C of the index returns of the main financial markets after the 2008 crisis using methods of random matrix theory. We test the eigenvalues of C for universal properties of random matrices and find that the majority of the cross-correlation coefficients arise from randomness. We show that the eigenvector of the largest deviating eigenvalue of C represents a global market itself. We reveal that high volatility of financial markets is observed at the same times with high correlations between them which lowers the risk diversification potential even if one constructs a widely internationally diversified portfolio of stocks. We identify and compare the connection and cluster structure of markets before and after the crisis using minimal spanning and ultrametric hierarchical trees. We find that after the crisis, the co-movement degree of the markets increases. We also highlight the key financial markets of pre and post crisis using main centrality measures and analyze the changes. We repeat the study using rank correlation and compare the differences. Further implications are discussed. © 2013 Elsevier B.V. All rights reserved
The long-term effects of a family based economic empowerment intervention (Suubi+Adherence) on suppression of HIV viral loads among adolescents living with HIV in southern Uganda: Findings from 5-year cluster randomized trial
BACKGROUND: The rapid scale-up of HIV therapy across Africa has failed to adequately engage adolescents living with HIV (ALWHIV). Retention and viral suppression for this group (ALWHIV) is 50% lower than for adults. Indeed, on the African continent, HIV remains the single leading cause of mortality among adolescents. Strategies tailored to the unqiue developmental and social vulnerabilities of this group are urgently needed to enhance successful treatment.
METHODS: We carried out a five-year longitudinal cluster randomized trial (ClinicalTrials.gov ID: NCT01790373) with adolescents living with HIV (ALWHIV) ages 10 to 16 years clustered at health care clinics to test the effect of a family economic empowerment (EE) intervention on viral suppression in five districuts in Uganda. In total, 39 accredited health care clinics from study districts with existing procedures tailored to adolescent adherence were eligible to participate in the trial. We used data from 288 youth with detectable HIV viral loads (VL) at baseline (158 -intervention group from 20 clinics, 130 -non-intervention group from 19 clinics). The primary end point was undetectable plasma HIV RNA levels, defined as \u3c 40 copies/ml. We used Kaplan-Meier (KM) analysis and Cox proportional hazard models to estimate intervention effects.
FINDINGS: The Kaplan-Meier (KM) analysis indicated that an incidence of undetectable VL (0.254) was significantly higher in the intervention condition compared to 0.173 (in non-intervention arm) translated into incidence rate ratio of 1.468 (CI: 1.064-2.038), p = 0.008. Cox regression results showed that along with the family-based EE intervention (adj. HR = 1.446, CI: 1.073-1.949, p = 0.015), higher number of medications per day had significant positive effects on the viral suppression (adj.HR = 1.852, CI: 1.275-2.690, p = 0.001).
INTERPRETATION: A family economic empowerment intervention improved treatment success for ALWHIV in Uganda. Analyses of cost effectiveness and scalability are needed to advance incorporation of this intervention into routine practice in low and middle-income countries
Evaluation of a savings-led family-based economic empowerment intervention for AIDS-affected adolescents in Uganda: A four-year follow-up on efficacy and cost-effectiveness
Background
Children who have lost a parent to HIV/AIDS, known as AIDS orphans, face multiple stressors affecting their health and development. Family economic empowerment (FEE) interventions have the potential to improve these outcomes and mitigate the risks they face. We present efficacy and cost-effectiveness analyses of the Bridges study, a savings-led FEE intervention among AIDS-orphaned adolescents in Uganda at four-year follow-up.
Methods
Intent-to-treat analyses using multilevel models compared the effects of two savings-led treatment arms: Bridges (1:1 matched incentive) and BridgesPLUS (2:1 matched incentive) to a usual care control group on the following outcomes: self-rated health, sexual health, and mental health functioning. Total per-participant costs for each arm were calculated using the treatment-on-the-treated sample. Intervention effects and per-participant costs were used to calculate incremental cost-effectiveness ratios (ICERs).
Findings
Among 1,383 participants, 55% were female, 20% were double orphans. Mean age was 12 years at baseline. At 48-months, BridgesPLUS significantly improved self-rated health, (0.25, 95% CI 0.06, 0.43), HIV knowledge (0.21, 95% CI 0.01, 0.41), self-concept (0.26, 95% CI 0.09, 0.44), and self-efficacy (0.26, 95% CI 0.09, 0.43) and lowered hopelessness (-0.28, 95% CI -0.43, -0.12); whereas Bridges improved self-rated health (0.26, 95% CI 0.08, 0.43) and HIV knowledge (0.22, 95% CI 0.05, 0.39). ICERs ranged from 298 for HIV knowledge per 0.2 standard deviation change.
Conclusions
Most intervention effects were sustained in both treatment arms at two years post-intervention. Higher matching incentives yielded a significant and lasting effect on a greater number of outcomes among adolescents compared to lower matching incentives at a similar incremental cost per unit effect. These findings contribute to the evidence supporting the incorporation of FEE interventions within national social protection frameworks
Effects of a combination economic empowerment and family strengthening intervention on psychosocial well-being among Ugandan adolescent girls and young women: Analysis of a cluster randomized controlled trial (Suubi4Her)
PURPOSE: Economic empowerment and family strengthening interventions have shown promise for improving psychosocial well-being in a range of populations. This study investigates the effect of a combination economic and family strengthening intervention on psychosocial well-being among Ugandan adolescent girls and young women (AGYW).
METHODS: We harnessed data from a three-arm cluster randomized controlled trial among AGYW aged 14-17 years in 47 Ugandan secondary schools. Schools were randomized to either a youth development account intervention (YDA) [N = 16 schools], YDA plus a multiple family group intervention (YDA + MFG) [N = 15 schools], or bolstered standard of care (BSOC) [N = 16 schools]. We estimated the effect of each intervention (BSOC = referent) on three measures of psychosocial well-being: hopelessness (Beck\u27s Hopelessness Scale), self-concept (Tennessee Self-Concept Scale), and self-esteem (Rosenberg Self-Esteem Scale) at 12 months following enrollment using multi-level linear mixed models for each outcome.
RESULTS: A total of 1,260 AGYW (mean age, 15.4) were enrolled-471 assigned to YDA (37%), 381 to YDA + MFG (30%), and 408 to usual care (32%). Over the 12-month follow-up, participants assigned to the YDA + MFG group had significantly greater reductions in hopelessness and improvements in self-esteem outcomes compared to BSOC participants. Those enrolled in the YDA arm alone also had significantly greater reductions in hopelessness compared to BSOC participants.
DISCUSSION: Combination interventions, combining economic empowerment (represented here by YDA), and family-strengthening (represented by MFG) can improve the psychosocial well-being of AGYW. The long-term effects of these interventions should be further tested for potential scale-up in an effort to address the persistent mental health treatment gap in resource-constrained settings
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