211 research outputs found

    Leakage-Resilient Tweakable Encryption from One-Way Functions

    Get PDF
    In this paper, we initiate the study of leakage-resilient tweakable encryption schemes in the relative key-leakage model, where the adversary can obtain (arbitrary) partial information about the secret key. We also focus on the minimal and generic assumptions needed to construct such a primitive. Interestingly, we show provably secure constructions of leakage-resilient (LR) tweakable encryption based on the sole assumption that one-way functions (OWF) exist via some interesting intermediate generic connections. A central tool used in our construction of LR-tweakable encryption is the notion of Symmetric-key tweakable weak hash proof system, which we introduce. This can be seen as a generalization of the Symmetric-key weak hash proof framework of Hazay et. al (Eurocrypt\u2713). Along the way, we also introduce a new primitive called tweakable weak pseudo-random functions (t-wPRF) and show how to generically construct it from weak-PRF. We then construct LR-version of t-wPRF and use it to construct LR-tweakable encryption

    Phytophthora Blight Of Pigeon Pea In India

    Get PDF
    Isolations were made from blighted pigeon-pea (Cajanus cajan) plants from different locations in India. A species of Phytophthora was consistently obtained from these locations and was proved to be the causal organism involved in the disease. Based on the sporangium shape and size, oogonium and oospore formation, temperature requirements, and pathogenicity tests, we have classified these isolates as P. drechsleri f. sp. cajani. The use of formae speciales was considered appropriate because of the specificity of these isolates to pigeon pea and Atylosia spp., wild relatives of the pigeon pea

    Drug Use and Receipt of Highly Active Antiretroviral Therapy among HIV-Infected Persons in Two U.S. Clinic Cohorts

    Get PDF
    Drug use and receipt of highly active antiretroviral therapy (HAART) were assessed in HIV-infected persons from the Comprehensive Care Center (CCC; Nashville, TN) and Johns Hopkins University HIV Clinic (JHU; Baltimore, MD) between 1999 and 2005.Participants with and without injection drug use (IDU) history in the CCC and JHU cohorts were evaluated. Additional analysis of persons with history of IDU, non-injection drug use (NIDU), and no drug use from CCC were performed. Activity of IDU and NIDU also was assessed for the CCC cohort. HAART use and time on HAART were analyzed according to drug use category and site of care.1745 persons were included from CCC: 268 (15%) with IDU history and 796 (46%) with NIDU history. 1977 persons were included from JHU: 731 (35%) with IDU history. Overall, the cohorts differed in IDU risk factor rates, age, race, sex, and time in follow-up. In multivariate analyses, IDU was associated with decreased HAART receipt overall (OR = 0.61, 95% CI: [0.45-0.84] and OR = 0.58, 95% CI: [0.46-0.73], respectively for CCC and JHU) and less time on HAART at JHU (0.70, [0.55-0.88]), but not statistically associated with time on HAART at CCC (0.78, [0.56-1.09]). NIDU was independently associated with decreased HAART receipt (0.62, [0.47-0.81]) and less time on HAART (0.66, [0.52-0.85]) at CCC. These associations were not altered significantly whether patients at CCC were categorized according to historical drug use or drug use during the study period.Persons with IDU history from both clinic populations were less likely to receive HAART and tended to have less cumulative time on HAART. Effects of NIDU were similar to IDU at CCC. NIDU without IDU is an important contributor to HAART utilization

    The relationship between adverse neighborhood socioeconomic context and HIV continuum of care outcomes in a diverse HIV clinic cohort in the Southern United States

    Get PDF
    Retention in care and viral suppression are critical to delaying HIV progression and reducing transmission. Neighborhood socioeconomic context (NSEC) may affect HIV care receipt. We therefore assessed NSEC's impact on retention and viral suppression in a diverse HIV clinical cohort. HIV-positive adults with ≥1 visit at the Vanderbilt Comprehensive Care Clinic and 5-digit ZIP code tabulation area (ZCTA) information between 2008 and 2012 contributed. NSEC z-score indices used neighborhood-level socioeconomic indicators for poverty, education, labor-force participation, proportion of males, median age, and proportion of residents of black race by ZCTA. Retention was defined as ≥2 HIV care visits per calendar year, >90 days apart. Viral suppression was defined as an HIV-1 RNA <200 copies/mL at last measurement per calendar year. Modified Poisson regression was used to estimate risk ratios (RR) and 95% confidence intervals (CI). Among 2272 and 2541 adults included for retention and viral suppression analyses, respectively, median age and CD4 count at enrollment were approximately 38 (1st and 3rd quartile: 30, 44) years and 351 (176, 540) cells/μL, respectively, while 24% were female, and 39% were black. Across 243 ZCTAs, median NSEC z-score was 0.09 (-0.66, 0.48). Overall, 79% of person-time contributed was retained and 74% was virally suppressed. In adjusted models, NSEC was not associated with retention, though being in the 4th vs. 1st NSEC quartile was associated with lack of viral suppression (RR = 0.88; 95% CI: 0.80-0.97). Residing in the most adverse NSEC was associated with lack of viral suppression. Future studies are needed to confirm this finding

    Development and validation of a multivariable prediction model for missed HIV health care provider visits in a large US clinical cohort

    Get PDF
    Background: Identifying individuals at high risk of missing HIV care provider visits could support proactive intervention. Previous prediction models for missed visits have not incorporated data beyond the individual level. Methods: We developed prediction models for missed visits among people with HIV (PWH) with ≥1 follow-up visit in the Center for AIDS Research Network of Integrated Clinical Systems from 2010 to 2016. Individual-level (medical record data and patient-reported outcomes), community-level (American Community Survey), HIV care site-level (standardized clinic leadership survey), and structural-level (HIV criminalization laws, Medicaid expansion, and state AIDS Drug Assistance Program budget) predictors were included. Models were developed using random forests with 10-fold cross-validation; candidate models with the highest area under the curve (AUC) were identified. Results: Data from 382 432 visits among 20 807 PWH followed for a median of 3.8 years were included; the median age was 44 years, 81% were male, 37% were Black, 15% reported injection drug use, and 57% reported male-to-male sexual contact. The highest AUC was 0.76, and the strongest predictors were at the individual level (prior visit adherence, age, CD4+ count) and community level (proportion living in poverty, unemployed, and of Black race). A simplified model, including readily accessible variables available in a web-based calculator, had a slightly lower AUC of .700. Conclusions: Prediction models validated using multilevel data had a similar AUC to previous models developed using only individual-level data. The strongest predictors were individual-level variables, particularly prior visit adherence, though community-level variables were also predictive. Absent additional data, PWH with previous missed visits should be prioritized by interventions to improve visit adherence
    • …
    corecore