Perceived condom norms and HIV risks among social and sexual networks of young African American men who have sex with men.

The association between condom norms and unprotected sexual intercourse was examined within social and sexual networks of young African American men who have sex with men (MSM) in an HIV epicenter of the southern United States. We used a chain-link design to recruit 158 young African American men: 95 initial participants, 56 contacts of participants (alters) and 7 contacts of alters. Men in the high-risk group, compared with those in the no-risk group, perceived significantly lower approval concerning condom use in their social and sexual networks. Also, 100 participants could be connected to each other in 86 dyads of social and sexual networks. Within these dyads, men perceived that their friends and acquaintances approved for them to use condoms but that their friends and acquaintances did not use condoms themselves. Low HIV risk behavior appears associated with perceived social norms that support one's use of condoms, even when perceived norms do not support condom use by network members themselves.

Consistent Quantitative Trait Loci in Pea for Partial Resistance to Aphanomyces euteiches Isolates from the United States and France.

ABSTRACT Development of pea cultivars resistant to Aphanomyces root rot, the most destructive root disease of pea worldwide, is a major disease management objective. In a previous study of a mapping population of 127 recombinant inbred lines (RILs) derived from the cross 'Puget' (susceptible) x '90-2079' (partially resistant), we identified seven genomic regions, including a major quantitative trait locus (QTL), Aph1, associated with partial resistance to Aphanomyces root rot in U.S. fields (21). The objective of the present study was to evaluate, in the same mapping population, the specificity versus consistency of Aphanomyces resistance QTL under two screening conditions (greenhouse and field, by comparison with the previous study) and with two isolates of Aphanomyces euteiches originating from the United States and France. The 127 RILs were evaluated in the greenhouse for resistance to pure culture isolates SP7 (United States) and Ae106 (France). Using the genetic map previously described, a total of 10 QTL were identified for resistance in greenhouse conditions to the two isolates. Among these were Aph1, Aph2, and Aph3, previously detected for partial field resistance in the United States. Aph1 and Aph3 were detected with both isolates and Aph2 with only the French isolate. Seven additional QTL were specifically detected with one of the two isolates and were not identified for partial field resistance in the United States. The consistency of the detected resistance QTL over two screening environments and isolates is discussed with regard to pathogen variability, and disease assessment and QTL detection methods. This study suggests the usefulness of three consistent QTL, Aph1, Aph2, and Aph3, for marker-assisted selection.

Sources of Partial Resistance to Fusarium Root Rot in the Pisum Core Collection.

Fusarium root rot, caused by Fusarium solani f. sp. pisi, is one of the most important fungal diseases of pea and is found in most pea-growing areas around the world. Currently, no commercial cultivars are resistant to this pathogen. Availability of new sources of partial resistance could provide another tool for managing Fusarium root rot. In all, 387 accessions from the Pisum core collection were evaluated for resistance to Fusarium root rot in two independent experiments. Nonparametric analysis of variance conducted on ranks of disease severity for each accession indicated that the two experiments corresponded well. Forty-four plant introduction lines with a disease severity rating of 2.5 or less on a 0-to-5 scale (where 5 = completely rotted) were selected as being partially resistant to root rot. Immunity to Fusarium root rot was not found. Comparison of disease resistance data for Aphanomyces root rot and Fusarium root rot showed a weak, but significant and positive correlation. A complete listing of the data for the partial resistance of all accessions tested can be found at the National Plant Germplasm System website, United States Department of Agriculture-Agricultural Research Service.

Quantitative trait loci for partial resistance to Aphanomyces root rot in pea.

Aphanomyces root rot, caused by Aphanomyces euteiches Drechs, is the most-important disease of pea ( Pisum sativum L.) worldwide. No efficient chemicals are available to control the pathogen. To facilitate breeding for Aphanomyces root rot resistance and to better understand the inheritance of partial resistance, our goal was to identify QTLs associated with field partial resistance. A population of 127 RILs from the cross Puget (susceptible) x 90-2079 (partially resistant) was used. The lines were assessed for resistance to A. euteiches under field conditions at two locations in the United States (Pullman, Wash. and LeSueur, Minn.) in 1996 and 1998 for three criteria based on symptom intensity and disease effects on the whole plant. The RILs were genotyped using automated AFLPs, RAPDs, SSRs, ISSRs, STSs, isozymes and morphological markers. The resulting genetic map consisted of 324 linked markers distributed over 13 linkage groups covering 1,094 cM (Kosambi). Twenty seven markers were anchored to other published pea genetic maps. A total of seven genomic regions were associated with Aphanomyces root rot resistance. The first one, located on LG IVb and named Aph1, was considered as "major" since it was highly consistent over the years, locations and resistance criteria studied, and it explained up to 47% of the variation in the 1998 Minnesota trial. Two other year-specific QTLs, namely Aph2 and Aph3, were revealed from different scoring criteria on LG V and Ia, respectively. Aph2 and Aph3 mapped near the r (wrinkled/round seeds) and af (normal/afila leaves) genes, and accounted for up to 32% and 11% of the variation, respectively. Four other "minor" QTLs, identified on LG Ib, VII and B, were specific to one environment and one resistance criterion. The resistance alleles of Aph3 and the two "minor" QTLs on LG Ib were derived from the susceptible parent. Flanking markers for the major Aphanomyces resistance QTL, Aph1, have been identified for use in marker-assisted selection to improve breeding efficiency.

Factors associated with sunburn in white children aged 6 months to 11 years.

OBJECTIVE: To determine the sunburn experience and factors associated with sunburn among white children aged 6 months to 11 years. METHODS: Telephone interviews were conducted with parents and primary caretakers of children, selected by random, stratified sampling, in the contiguous United States in the summer of 1998. Information was gathered on demographic characteristics of parents and children, and children's sunburn experience during the past year, protection from sun exposure, and hours per week spent outdoors. The proportion of children experiencing sunburn in the past year was calculated. Multivariate logistic regression analyses were conducted to determine factors associated with sunburn. Information for 1052 white children was available for the analyses. RESULTS: An estimated 42.6% of U.S. white children experienced one or more sunburns within the past year (95% CI 38.2-47.0). Sunburn was less common among children who ever wore hats (adjusted OR 0.59, 95% CI 0.40-0.87) and more common among children who did not always wear sunscreen (OR for using sunscreen sometimes compared with always, 2.25; 95% CI 1.31-3. 86). Sunburn was also more common among children with sun-sensitive skin and older children. CONCLUSIONS: A large proportion of U.S. white children experience sunburns. Parents and children may benefit from education about protection from sun exposure.

Protection from sun exposure in US white children ages 6 months to 11 years.

OBJECTIVES: To estimate the prevalence of protection from sun exposure among US white children ages 6 months to 11 years. METHODS: During the summer of 1998, using telephone directory lists supplemented by random-digit dialing, the authors surveyed parents living in the contiguous United States. They calculated weighted prevalence estimates for protection methods and conducted logistic regression analyses to determine parent and child characteristics predictive of protection behaviors. RESULTS: Parents of 1,055 white children were interviewed. Children spent a median of 20 hours per week outdoors during the summer, of which 10 hours were at school. Sunscreen (61.8%, 95% confidence interval [CI] 57%, 66%) and shade (26.5%, 95% CI 22%, 31%) were the most frequently reported protection methods. Parents reported higher rates of protection for younger children and children who sunburn easily. CONCLUSIONS: Parents report that a large proportion of white children is protected from sun exposure by one or more methods. Health care providers and educators might encourage the use of all methods of protection, not just sunscreen use, and educate older children to protect themselves from the sun.

A technology transfer model for effective HIV/AIDS interventions: science and practice.

The widespread use of effective, science-based interventions to motivate and sustain behavior change provides an important approach to reducing the spread of HIV. The process of disseminating information about effective interventions and building capacity for implementing them in field settings must be improved, however. Starting with a review of diffusion of innovations and technology transfer literature, we offer a technology transfer model for HIV interventions. We identify participants and activities directed toward the use of effective interventions by prevention services providers (e.g., health departments and community-based organizations) in each phase of technology transfer: preimplementation, implementation, and maintenance and evolution. Preimplementation activities focus on selecting an intervention and preparing for implementation. Implementation activities include initial implementation and process evaluation. Maintenance and evolution are ongoing with continued support for and evaluation of the intervention. This article takes the perspective of providers. Other perspectives are presented elsewhere in this issue.

Finding the "community" in community-level HIV/AIDS interventions: formative research with young African American men who have sex with men.

Data from 76 qualitative interviews with 18- to 29-year-old African American men who have sex with men (MSM) in Chicago and Atlanta were examined to identify perceptions of "community" and components of a community-level HIV/AIDS intervention. Many men reported feeling marginal to African American and gay White communities because of perceived homophobia and racism. Those who reported feeling part of gay African American communities characterized communities in terms of settings, social structures, and functions, including social support, socialization, and mobility. Despite these positive functions, divisions among groups of MSM, lack of settings for nonsexual interaction with other MSM, lack of leadership, and negative attitudes toward homosexuality may make it difficult for men to participate in activities to alter community contexts that influence behavior. Rather, changing norms, increasing social support, and community building should be part of initial community-level interventions. Community building might identify leaders, create new settings, and create opportunities for dialogue between MSM and African American community groups to address negative perceptions of homosexuality.

Engaging women's interest in colorectal cancer screening: a public health strategy.

Screening rates for colorectal cancer are unacceptably low. New guidelines, public education campaigns, and expanded coverage of screening costs by healthcare insurance are expected to increase screening rates, but interventions targeting women may accelerate this change. Most American women already participate in regular cancer screening, in the form of Papanicolaou (Pap) tests and mammography, so they may be receptive to tailored messages about the need to add regular colorectal cancer screening to their preventive health regimen. In addition, their role in promoting the health of family members may position women to influence screening behavior in family and friends. Women may be particularly valuable change agents in populations where screening rates are traditionally low, such as medically underserved populations, the elderly or low socioeconomic status groups with competing health priorities, and populations with cultural values or practices inconsistent with the adoption of a new screening behavior. To serve as agents of change in their family and social networks, women must understand that colorectal cancer is not solely a man's disease and that the benefits of colorectal screening are similar to those of Pap testing and mammography. Colorectal cancer screening should also be promoted within a framework of a lifelong strategy for health maintenance for both men and women. The message to women should emphasize the value of colorectal cancer screening rather than the disagreement among experts over preferred screening strategies and should emphasize the value of shared decision making between the patient and her healthcare provider.

Colorectal cancer screening in older men and women: qualitative research findings and implications for intervention.

As part of the formative research for developing interventions to increase colorectal cancer screening in men and women aged 50 and older, 14 focus groups were conducted to identify (1) knowledge, attitudes, and beliefs about colorectal cancer and colorectal cancer screening, (2) barriers to screening, and (3) strategies for motivating and supporting behavior change. Participants had either private insurance or Medicare and reported different levels of experience with colorectal cancer screening. Overall, they were poorly informed about colorectal cancer and the possible benefits of screening, reporting little or no information from physicians or mass media, negative attitudes toward screening procedures, and fear of cancer. Despite references to the subject matter as embarrassing or private, both men and women, African Americans and whites, appeared to talk candidly and comfortably in the permissive context of the focus group. This study's findings suggest that public education campaigns, decision aids, and targeted interventions are urgently needed to put colorectal cancer screening on the public's "radar screen," to increase awareness of the prevention and early detection benefits of screening, and to encourage people 50 and older-and the health care providers who serve them-to make screening a high priority.

A PCR-Based Assay by Sequence-Characterized DNA Markers for the Identification and Detection of Aphanomyces euteiches.

ABSTRACT Polymerase chain reaction (PCR) products were identified and amplified from isolates of Aphanomyces euteiches and A. cochlioides. The products were cloned and sequenced, and the data were used to design pairs of extended PCR primers to amplify sequence-characterized DNA markers. The primer pair OPC7-FS-30 and OPC7-RS-25 amplified a single 1,332-bp product from all isolates of A. euteiches that were not amplified from any other isolates tested. A single 718-bp product was selectively amplified only from isolates of A. cochlioides with the primer pair OPB10-FS-25 and OPB10-RS-25. A. euteiches was detected in roots of several varieties of field-grown peas collected from a root rot trial site. PCR also detected A. euteiches in the organic fraction of field soil samples. Both pairs of extended primers were used in a multiplex reaction to unambiguously discriminate between A. euteiches and A. cochlioides. Both pairs of primers were used in two-step PCR reactions in which annealing and extension was done in a single step at 72 degrees C. This reduced the time required for amplification of the diagnostic PCR product and its resolution by electrophoresis to less than 3 h.

Retinoic acid promotes rod photoreceptor differentiation in rat retina in vivo.

Previous studies have indicated that retinoic acid (RA) promotes rod photoreceptor differentiation in dissociated cultures of rat retina and in zebrafish embryos. To determine whether RA will have the same affect in the mammalian retina in vivo, pregnant rats were given single i.p. injections of RA on the 18th and 20th days of gestation, and the retinas of the pups were analyzed for rods. HPLC showed that i.p. injections of RA substantially increased levels of retinal RA in the embryos. Embryonic exposure to RA caused an increase in the number of cells that differentiated as rod photoreceptors. There was a comparable decrease in the number of cells that differentiated as amacrine cells. These results demonstrate that RA promotes the differentiation of rods in vivo and further support the hypothesis that differentiation of rods is normally controlled partly by the RA concentration in the developing retina or RPE.

Aging and the saturation of colors. 1. Colorimetric purity discrimination.

Colorimetric purity (Pc) discrimination functions were measured for 21 color-normal observers (11 younger and 10 older observers with mean ages of 30 and 74 years, respectively). On each two-alternative-forced-choice trial, observers saw two flashes of light, a broadband white light [CIE(x, y) = (0.33, 0.35)] and a mixture of broadband and monochromatic light (420-680 nm). The observer's task was to choose the flash that had a chromatic component. Foveally viewed, circular, 1.2 degrees-diameter stimuli were presented as 1.5-s flashes with 3-s interstimulus intervals in Maxwellian view. Stimuli [250 trolands (td) and 10 td] were equated on the basis of individual heterochromatic flicker photometry functions. Measured Pc discrimination sensitivity was lower in the older group than in the younger group at both light levels, and the performance difference between the age groups was approximately constant across the spectrum. The difference between discrimination at 10 and 250 td was relatively small for the younger group but larger for the older group, indicating a selective performance decrement for older observers at low light levels. The data were modeled as a sum of differential responses from S-cone and L/M-cone chromatic channels. The model and the data indicate similar age-related losses of sensitivity in the two channels, perhaps secondary to receptorial sensitivity losses.

Aging and the saturation of colors. 2. Scaling of color appearance.

Saturation of two sets of stimuli was scaled by 21 color-normal observers (ten younger and 11 older observers, mean ages: 30 and 73 years). Circular fields, 1.2 degrees in diameter, were presented in Maxwellian view as 1.5-s flashes with 3-s interstimulus intervals. Stimuli were mixtures of broadband light [CIE(x, y) = (0.35, 0.39), 200 trolands (td)] and monochromatic light (420-700 nm, 50 td). Monochromatic lights were equated by the 1978 2 degrees fundamental observer's luminosity function in one set of stimuli [J. J. Vos, Color Res. Appl. 3, 125 (1978) and by each observer's heterochromatic flicker photometry function in the other set of stimuli. Comparing the two age groups reveals no sizable differences in saturation for either set of stimuli, neither supporting nor refuting neural compensation for age-related increases in ocular media density (OMD). Examining short-wavelength saturation as a continuous function of estimated OMD reveals a more complicated pattern of results, however, suggesting substantial compensation over a certain range of OMD values but incomplete compensation for observers with the highest OMD values.

Mechanisms of color constancy under nearly natural viewing.

Color constancy is our ability to perceive constant surface colors despite changes in illumination. Although color constancy has been studied extensively, its mechanisms are still largely unknown. Three classic hypotheses are that constancy is mediated by local adaptation, by adaptation to the spatial mean of the image, or by adaptation to the most intense image region. We measure color constancy under nearly natural viewing conditions, by using a design that allows us to test these three hypotheses directly. By suitable stimulus manipulation, we are able to titrate the degree of constancy between 11% and 83%, indicating that we have achieved good laboratory control. Our results rule out all three classic hypotheses and thus suggest that there is more to constancy than can be easily explained by the action of simple visual mechanisms.

Effects of known variations in photopigments on L/M cone ratios estimated from luminous efficiency functions.

The extent to which known variations in photopigment lambda max and optical density may affect cone ratios estimated from the spectral luminous efficiency function (LEF) was examined. LEFs were generated using L- and M-cone fundamentals, one of which had been shifted in lambda max (+/- 1, 2, 4 or 6 nm) or varied in peak optical density (increased or decreased by 10, 25 or 50%). A curve-fitting program was then used to estimate the L/M cone ratios for the generated LEFs assuming standard L- and M-cone fundamentals. These modeling exercises indicate that L/M cone ratios estimated from LEFs are highly correlated with long-wave sensitivity and with known variations in L-cone lambda max. Variations in M-cone lambda max and photopigment optical density for both cone types are also correlated with L/M cone ratios, but have much less impact on the estimated ratios.

Employment and the use of birth control by sexually active single Hispanic, black, and white women.

Previous studies of the use of birth control by sexually active single women tend to emphasize family background and aspirations, and restrict their attention to teenagers. We elaborate this framework by considering how labor market experiences might shape the birth control practices of women in their late teens and twenties. Data from the National Longitudinal Survey of Labor Force Experiences--Youth Cohort provide evidence that employment histories and wages influence birth control practices, net of the effects of family background, aspirations, and educational attainment. Several pronounced racial and ethnic differences are found.

Spectral efficiency across the life span: flicker photometry and brightness matching.

Spectral efficiency functions were measured for 50 color-normal observers (aged 19-85 years) by means of heterochromatic flicker photometry (HFP) and heterochromatic brightness matching (HBM). Foveally viewed, circular, 1.2 degrees-diameter stimuli were presented as 3-s flashes (50% duty cycle) in Maxwellian view. Monochromatic lights (420-700 nm; 16 wavelengths) were equated to a 100-Td (trolands), broadband white standard in both procedures. In both HFP and HBM, average sensitivity (specified at the cornea) decreased at short wavelengths with increasing age, consistent with age-related increases in the density of the ocular media. The short-wavelength HBM decline was of lower magnitude than the HFP decline. HFP data were modeled by a weighted additive combination of long- and middle-wavelength-cone inputs and density spectra of the ocular media and macular pigment. HBM data were analyzed with an upper envelope of additive and subtractive combinations of log-transformed cone absorption functions. These analyses indicated that HBM sensitivity, specified at the retina by correction for estimated lens and macular pigment density, increased with age in an approximately wavelength-independent manner over a broad range from 420 to 560 nm.

Drinking patterns and the gender mix of occupations: evidence from a national survey of American workers.

The linkage of the gender mix of occupations to drinking patterns has been suggested by Wilsnack and Wilsnack (1991). Using a national sample of American workers, associations among gender, the gender mix of occupations, occupation, and drinking variables were explored. The results suggest that the relationship between the gender mix of occupations and drinking variables operates through opportunities to drink with coworkers. Gender mix is associated with opportunities to drink with coworkers. Opportunities to drink with coworkers are, in turn, associated with whether respondents drink, who they are with when they drink, average number of drinks per month, and CAGE scores. Gender is associated with opportunities to drink with coworkers, drinks per month, and CAGE scores. Occupation is associated with opportunities to drink with coworkers, drinking patterns, and problem drinking. Further elaboration of the mechanisms linking the gender mix of occupations and drinking patterns is warranted.