Assessing Causality in the Relationship Between Adolescents’ Risky Sexual Online Behavior and Their Perceptions of this Behavior

The main aim of this study was to investigate the causal nature of the relationship between adolescents’ risky sexual behavior on the internet and their perceptions of this behavior. Engagement in the following online behaviors was assessed: searching online for someone to talk about sex, searching online for someone to have sex, sending intimate photos or videos to someone online, and sending one’s telephone number and address to someone exclusively known online. The relationship between these behaviors and adolescents’ perceptions of peer involvement, personal invulnerability, and risks and benefits was investigated. A two-wave longitudinal study among a representative sample of 1,445 Dutch adolescents aged 12–17 was conducted (49% females). Autoregressive cross-lagged structural equation models revealed that perceived peer involvement, perceived vulnerability, and perceived risks were all significant predictors of risky sexual online behavior 6 months later. No reverse causal paths were found. When the relationships between perceptions and risky sexual online behavior were modeled simultaneously, only perceived peer involvement was a determinant of risky sexual online behavior. Findings highlight the importance of addressing peer involvement in future interventions to reduce adolescents’ risky sexual online behavior

A Functional Genomics Approach to Establish the Complement of Carbohydrate Transporters in Streptococcus pneumoniae

The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium∶solute symporter and a permease, underlining an exceptionally high capacity for uptake of carbohydrate substrates. Despite high genomic variability, combined phenotypic and genomic analysis of twenty sequenced strains did assign the substrate specificity only to two uptake systems. Systematic analysis of mutants for most carbohydrate transporters enabled us to assign a phenotype and substrate specificity to twenty-three transport systems. For five putative transporters for galactose, pentoses, ribonucleosides and sulphated glycans activity was inferred, but not experimentally confirmed and only one transport system remains with an unknown substrate and lack of any functional annotation. Using a metabolic approach, 80% of the thirty-two fermentable carbon substrates were assigned to the corresponding transporter. The complexity and robustness of sugar uptake is underlined by the finding that many transporters have multiple substrates, and many sugars are transported by more than one system. The present work permits to draw a functional map of the complete arsenal of carbohydrate utilisation proteins of pneumococci, allows re-annotation of genomic data and might serve as a reference for related species. These data provide tools for specific investigation of the roles of the different carbon substrates on pneumococcal physiology in the host during carriage and invasive infection

Die Bevoelkerungsentwicklung in den nordthueringischen Kreisen Nordhausen, Worbis und Heiligenstadt von 1939 bis 1964 eine oekonomisch-geographische Untersuchung

DB Leipzig(101) - Di 1978 B VD 3 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Heterogeneous resource management and orchestration in cloud environments

The addition of heterogeneous resources to conventional homogeneous cloud environments has enabled clouds to embrace a wide variety of new applications that heretofore were traditionally confined to specialized computing environments. The enhanced and extended features offered by heterogeneous resources enable service offerings that pose challenges to traditional cloud management throughout the entire service delivery stack. The accelerated uptake of heterogeneous resources is exacerbating these challenges, which no longer can be efficiently addressed in an ad-hoc manner. Therefore, an integrated approach to heterogeneous resource management that is cognizant of the unique advantages of different hardware types is needed. In this paper, two candidate approaches, a platform-integration scheme and a server-integration scheme, are introduced to address this management challenge. The platform-integration scheme integrates and coordinates the management of various coexisting resource managers and associated environments each of which may be managing resources of different types using the most appropriate resource abstraction method. In contrast, the server-integration scheme provides a single, lower level, fine-grained management mechanism across all hardware resource types. Ultimately, the goal of each schemes is to provide a unified view of resources from a capability perspective to consumers