20 research outputs found

    Sexual Dimorphism of Staminate- and Pistillate-Phase Flowers of Saponaria officinalis (Bouncing Bet) Affects Pollinator Behavior and Seed Set

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    The sequential separation of male and female function in flowers of dichogamous species allows for the evolution of differing morphologies that maximize fitness through seed siring and seed set. We examined staminate- and pistillate-phase flowers of protandrous Saponaria officinalis for dimorphism in floral traits and their effects on pollinator attraction and seed set. Pistillate-phase flowers have larger petals, greater mass, and are pinker in color, but due to a shape change, pistillate-phase flowers have smaller corolla diameters than staminate-phase flowers. There was no difference in nectar volume or sugar content one day after anthesis, and minimal evidence for UV nectar guide patterns in staminate- and pistillate-phase flowers. When presented with choice arrays, pollinators discriminated against pistillate-phase flowers based on their pink color. Finally, in an experimental garden, in 2012 there was a negative correlation between seed set of an open-pollinated, emasculated flower and pinkness (as measured by reflectance spectrometry) of a pistillate-phase flower on the same plant in plots covered with shade cloth. In 2013, clones of genotypes chosen from the 2012 plants that produced pinker flowers had lower seed set than those from genotypes with paler flowers. Lower seed set of pink genotypes was found in open-pollinated and hand-pollinated flowers, indicating the lower seed set might be due to other differences between pink and pale genotypes in addition to pollinator discrimination against pink flowers. In conclusion, staminate- and pistillate-phase flowers of S. officinalis are dimorphic in shape and color. Pollinators discriminate among flowers based on these differences, and individuals whose pistillate-phase flowers are most different in color from their staminate-phase flowers make fewer seeds. We suggest morphological studies of the two sex phases in dichogamous, hermaphroditic species can contribute to understanding the evolution of sexual dimorphism in plants without the confounding effects of genetic differences between separate male and female individuals

    Research Note: Factors associated with skin cleaning prior to injection among drug users.

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    Injection drug users are at risk for a variety of infections when hygienic injection practices are not performed. Disinfecting the injection site prior to injecting reduces the risk of bacterial infections but has been overlooked in many prevention efforts. Using what is known about factors associated with risk-reduction behaviors of disinfecting equipment, we evaluated a model to determine whether those factors are associated with disinfection of the injection site. Sociodemographic and behavioral data were collected in interviews with 600 injection drug users. The majority of injection drug users do not clean the injection site prior to injecting. Results indicate that gender, ethnicity, and frequency of injection were significantly related to whether or not an injector cleaned the injection site. Failure to clean the injection site prior to injecting is a common practice and constitutes a health risk among injection drug users, particularly in a population prone to other infections. Prevention efforts need to incorporate all levels of sterilization procedures when working with these high risk populations. </jats:p

    The Internet as recruitment tool for HIV studies: Viable strategy for reaching at-risk Hispanic MSM in Miami?

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    Although use of the Internet as a vehicle for HIV/STI research is increasing, its viability to recruit at-risk populations such as Hispanic men who have sex with men (HMSM) to participate in community-based HIV studies is in its infancy.We report on the first 171 participants enrolled in an ongoing study exploring use of the Internet to recruit Hispanic men who have sex with men (HMSM) living in Miami-Dade County, Florida to participate in community-based studies. We report our initial success with chat-room recruitment and describe the sexual and drug use practices of the initial set of participants who were recruited through the Internet. In addition, we describe the formative work conducted to develop the Internet recruitment procedures we are testing. In two months, we spent 211 hours recruiting in chat-rooms and engaged 735 chatters. One hundred and seventy-six men came to our community sites; 172 (98%) were eligible and completed an audio computer-assisted self-interview. In the previous six months, 94.7% of participants had anal sex; 48.9% did not use condoms for anal sex or used them inconsistently; and 48.5% had used club drugs. Six-month use rates for individual drugs were: poppers (31.6%), cocaine (15.8%), ecstasy (14%) and crystal methamphetamines (11.7%). Use of club drugs was significantly associated with unprotected insertive and unprotected receptive anal sex. These initial findings point to the Internet’s potential as a tool for recruiting at-risk Hispanic MSM for community studies

    Surfing New Territory: Club-Drug Use and Risky Sex Among Hispanic Men Who Have Sex with Men Recruited on the Internet

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    The Internet presents unique and growing opportunities for conducting HIV/ STD research. This article reports on the first 171 participants enrolled in an ongoing study examining use of the Internet to recruit Hispanic men who have sex with men (HMSM) living in an AIDS epicenter to participate in community-based studies. First, it describes initial success with chatroom recruitment. Second, it compares the demographic, psychosocial, and sexual risk practices among HMSM recruited through the Internet who had used club drugs in the last 6 months and those who had not. In 2 months, 211 hours were spent recruiting in chatrooms; 735 chatroom users were engaged. Researchers used a scripted dialogue to describe the study and to invite chatroom users to visit the study’s community sites for screening and enrollment. One hundred and seventy-six men came to the community sites; 172 (98%) were eligible and completed an audio-computer assisted self-interview. In the last 6 months, 48.5% of the sample had used club drugs [defined as cocaine, crystal methamphetamines (crystal), amyl nitrites (poppers), Ecstasy, gammahydroxybutyrate (GHB), ketamine (Special K), and Viagra]. The proportion of men reporting use of each drug was: cocaine (15.8%), crystal (11.7%), poppers (31.6%), Ecstasy (14%), GHB (3.5%), Special K (3.5%), and Viagra (19.3%). In multivariate analyses, having higher number of sex partners, having higher social isolation scores, and having engaged in unprotected receptive anal intercourse were significantly associated with club-drug use. These initial findings suggest that high-risk HMSM can be successfully recruited through chatroom dialogues to participate in community-based HIV studies. The alarmingly high rates of club-drug use and risky sexual practices among HMSM underscore the need for effective HIV preventive interventions for this population
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