28 research outputs found

    Comprehensive and interactive temporal query processing with SAP HANA

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    In this demo, we present a prototype of a main memory database system which provides a wide range of temporal operators featuring predictable and interactive response times. Much of real-life data is temporal in nature, and there is an increasing application demand for temporal models and operations in databases. Nevertheless, SQL:2011 has only recently overcome a decade-long standstill on standardizing temporal features. As a result, few database systems provide any temporal support, and even those only have limited expressiveness and poor performance. Our prototype combines an in-memory column store and a novel, generic temporal index structure named Timeline Index. As we will show on a workload based on real customer use cases, it achieves predictable and interactive query performance for a wide range of temporal query types and data sizes.</jats:p

    Current concepts of HIV transmission

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    The epithelial surface acts as an effective barrier against HIV. The various mucosal surfaces possess specific mechanisms that help prevent the transmission of virus. Yet, HIV manages to cross these barriers to establish infection, and this is enhanced in the presence of physical trauma or pre-existing sexually transmitted infections. Once breached, the virus accesses numerous cells such as dendritic cells, T cells, and macrophages present in the underlying epithelia. Although these cells should contribute to innate and adaptive immunity to infection, they also serve as permissive targets to HIV and help in the initiation and dissemination of infection. Understanding how the various mucosal surfaces, and the cells within them, respond to the presence of HIV is essential in the design of therapeutic agents that will help to prevent HIV transmission

    Band Bending and Trap Distribution along the Channel of Organic Field-Effect Transistors from Frequency-Resolved Scanning Photocurrent Microscopy

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    The scanning photocurrent microscopy (SPCM) method is applied to pentacene field-effect transistors (FETs). In this technique, a modulated laser beam is focused and scanned along the channel of the transistors. The resulting spatial photocurrent profile is attributed to extra free holes generated from the dissociation of light-created excitons after their interaction with trapped holes. The trapped holes result from the local upward band bending in the accumulation layer depending on the applied voltages. Thus, the photocurrent profile along the conducting channel of the transistors reflects the pattern of the trapped holes and upward band bending under the various operating conditions of the transistor. Moreover, it is found here that the frequency-resolved SPCM (FR-SPCM) is related to the interaction of free holes via trapping and thermal release from active probed traps of the first pentacene monolayers in the accumulation layer. The active probed traps are selected by the modulation frequency of the laser beam so that the FR-SPCM can be applied as a spectroscopic technique to determine the energy distribution of the traps along the transistor channel. In addition, a crossover is found in the FR-SPCM spectra that signifies the transition from empty to partially empty probed trapping states near the corresponding trap quasi-Fermi level. From the frequency of this crossover, the energy gap from the quasi-Fermi Etp level to the corresponding local valence band edge Ev, which is bent up by the gate voltage, can be estimated. This allows us to spatially determine the magnitude of the band bending under different operation conditions along the channel of the organic transistors

    Band Bending and Trap Distribution along the Channel of Organic Field-Effect Transistors from Frequency-Resolved Scanning Photocurrent Microscopy

    No full text
    The scanning photocurrent microscopy (SPCM) method is applied to pentacene field-effect transistors (FETs). In this technique, a modulated laser beam is focused and scanned along the channel of the transistors. The resulting spatial photocurrent profile is attributed to extra free holes generated from the dissociation of light-created excitons after their interaction with trapped holes. The trapped holes result from the local upward band bending in the accumulation layer depending on the applied voltages. Thus, the photocurrent profile along the conducting channel of the transistors reflects the pattern of the trapped holes and upward band bending under the various operating conditions of the transistor. Moreover, it is found here that the frequency-resolved SPCM (FR-SPCM) is related to the interaction of free holes via trapping and thermal release from active probed traps of the first pentacene monolayers in the accumulation layer. The active probed traps are selected by the modulation frequency of the laser beam so that the FR-SPCM can be applied as a spectroscopic technique to determine the energy distribution of the traps along the transistor channel. In addition, a crossover is found in the FR-SPCM spectra that signifies the transition from empty to partially empty probed trapping states near the corresponding trap quasi-Fermi level. From the frequency of this crossover, the energy gap from the quasi-Fermi Etp level to the corresponding local valence band edge Ev, which is bent up by the gate voltage, can be estimated. This allows us to spatially determine the magnitude of the band bending under different operation conditions along the channel of the organic transistors

    A systematic review of alcohol use and sexual risk-taking in Latin America

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    OBJECTIVE: To provide an account of published literature on the association between alcohol use and sexual risk-taking, focusing on Latin America. METHODS: A search of MEDLINE, Embase, Web of Science, LILACS, and Cochrane databases identified 561 unique articles. After excluding those that were not directly relevant, 30 studies were retained for review. RESULTS: Twenty-seven studies showed direct or indirect associations between alcohol abuse and unprotected/risky sex. Three studies, however, showed no association between these variables, suggesting that the public health message of safer sex may have been effective. CONCLUSIONS: Further research is needed to identify factors and behaviors that could be modified to reduce the association between alcohol use disorders and risky sexual behavior

    Tonsillar application of AT-2 SIV affords partial protection against rectal challenge with SIVmac239

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    Background: Although mucosal responses are important for preventing infections with HIV, the optimal strategies for inducing them remain unclear. To evaluate vaccine strategies targeting the oral mucosal lymphoid tissue inductive sites as an approach to provide immunity at distal sites, we vaccinated healthy macaques via the palatine/lingual tonsils with aldrithiol 2 (AT-2) inactivated Simian immunodeficiency virus (SIV)mac239, combined with CpG-C immunostimulatory oligonucleotide (CpG-C ISS-ODN, C274) as the adjuvant. Methods: Macaques received 5 doses of C274 or control ODN C661 and AT-2 SIV on the tonsillar tissues every 6 weeks before being challenged rectally with SIVmac239, 8 weeks after the last immunization. Results: Although no T-cell or B-cell responses were detected in the blood before challenge, antibody (Ab) responses were detected in the rectum. Immunization with AT-2 SIV significantly reduced the frequency of infection compared with nonimmunized controls, irrespective of adjuvant. In the vaccinated animals that became infected, peak viremias were somewhat reduced. SIV-specific responses were detected in the blood once animals became infected with no detectable differences between the differently immunized groups and the controls. Conclusion: This work provides evidence that vaccine immunogens applied to the oral mucosal associated lymphoid tissues can provide benefit against rectal challenge, a finding with important implications for mucosal vaccination strategies

    Screening for drug and alcohol use disorders and their association with HIV-related sexual risk behaviors among men who have sex with men in Peru.

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    Peru's HIV epidemic is concentrated among men who have sex with men (MSM). The contribution of alcohol use disorders (AUDs) to known high-risk behaviors associated with HIV transmission in this context has not been well characterized.Between June and October 2011, 5,148 sexually active MSM were recruited using convenience sampling in five cities to participate in a cross-sectional bio-behavioral survey. Five high-risk sexual criteria previously associated with incident HIV infection in this setting were selected a priori as the dependent outcomes. Screening for AUDs used the validated Alcohol Use Disorders Identification Test (AUDIT) and AUDS were stratified by severity. Unadjusted and adjusted odds ratios (AOR) were computed to establish the independent correlates of the five dependent outcomes.The majority (62.8%) of participants met screening criteria for having an AUD, which were independently correlated with each of the following high-risk sexual risk behaviors in the previous 6 months: 1) >5 sexual partners [AOR = 1.76; (1.54-2.02)]; 2) sex with an HIV-infected partner [AOR = 1.29; (1.03-1.62)]; 3) having a sexually transmitted infection [AOR = 1.38; (1.13-1.68)]; 4) being a sex worker [AOR = 1.61; (1.40-1.87)]; and 5) unprotected sex during last encounter [AOR = 1.22; (1.09-1.38)]. Recent drug use was also correlated with having >5 sexual partners [AOR = 1.42 (1.19-1.71)], sex work [AOR = 1.97 (1.63-2.39)] and unprotected sex during last encounter [AOR = 1.31 (1.11-1.54)]. For each dependent variable, the association with AUDs significantly increased with increasing AUD severity.AUDs are highly prevalent among MSM in Peru and are associated with increased HIV risk-taking behaviors that are associated with HIV transmission. Strategies that target problematic drinking such as medication-assisted therapy, behavioral counseling and structural interventions could potentially reduce risky behaviors and ultimately reduce HIV transmission among MSM in Peru

    A Qualitative Assessment of Alcohol Consumption and Sexual Risk Behaviors Among Men Who Have Sex With Men and Transgender Women in Peru.

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    BackgroundPeruvian men who have sex with men (MSM) and transgender women (TGW) experience the double burden of a highly concentrated HIV epidemic with a high prevalence of alcohol use disorders (AUDs). Recent research has associated both with risky sexual behaviors, including unprotected sex, having multiple sexual partners, engaging in sex work, having recent sexually transmitted infections, and having HIV-infected partners. AUDs have also been associated in MSM/TGW with being unaware of HIV+ status.ObjectivesThis study aims to further examine issues associated with alcohol consumption, HIV infection, and risk behaviors in a qualitative analysis of focus groups conducted with MSM/TGW in Peru.MethodsA total of 26 MSM/TGW participants with AUDs participated in three semi-structured focus groups in Lima, Peru. Content analysis was facilitated by software, and specific themes were elucidated.ResultsParticipants described their drinking patterns, including the types of alcoholic drinks they consumed. They depicted drinking frequently and over multiple-day sessions. Problematic drinking behaviors were described, as well as the perceived characteristics of alcohol dependence. Interestingly, HIV-infected participants who were prescribed antiretroviral therapy did not believe that their drinking affected their medication adherence. These insights can aid in the design of future interventions aiming to reduce problematic drinking as well as HIV-related risk behaviors and, subsequently, HIV incidence.ConclusionsPeruvian MSM/TGW exhibit problematic drinking, which may be associated with risky sexual behaviors and HIV transmission. Interest in reducing alcohol consumption was high, suggesting the need for targeted behavioral and pharmacological interventions
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