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The generally slow and incomplete recovery of the long-spined sea urchin, Diadema antillarum, from the 1983-84 Caribbean-wide die-off, particularly in the Florida Keys, USA, raises the question of factors limiting population recovery. This study sought to quantify larval settlement rates as an indicator of larval supply at two sites in the Florida Keys, utilizing methods comparable to an historic study. Settlement at two sites in southwest Puerto Rico was also examined as a comparison of present-day settlement rates at a site where D. antillarum recovery has been moderate. Monthly settlement rates were low (max < 2 m-2) and did not differ between the two sites examined in the Florida Keys. Settlement was significantly higher at only one of the Puerto Rico sites (max 16 m-2), but still an order of magnitude lower than that reported for historic populations in Curaçao (1982-83). Results are consistent with the hypothesis of low larval supply limiting D. antillarum recovery in the Florida Keys. [ABSTRACT FROM AUTHOR]

Association studies using single nucleotide polymorphisms (SNPs) have the potential to help unravel the genetic basis of hypertension. Nevertheless, to date, association studies of hypertension have yielded ambiguous results. It is becoming clear that such association studies must be interpreted within the context of the genetic structure of the populations being studied, and patterns of variation within specific genomic regions. With this in mind we analyzed genetic variation in the G protein-coupled receptor kinase 4 (GRK4) gene, a gene whose product has recently been shown to inhibit the dopamine receptor D1 (DRD1) from increasing sodium excretion. We genotyped three previously identified GRK4 SNPs, as well as ten additional SNPs, over 71.6 kb of the GRK4 locus in four populations: African Americans, Asians, Hispanics and Caucasians. Haplotype structure varied among populations, with Hispanics and Caucasians having the most linkage disequilibrium (LD) among SNPs. African Americans had three shorter haplotype blocks, while patterns of markers in the Asian populations demonstrated less LD among markers, a pattern inconsistent with block structure. We observed limited haplotype diversity in each of the four populations, with differing haplotype frequencies among the ethnic groups. We also found substantial evidence for population differentiation, with the largest differences between the African-American and Asian samples with F(ST) values in the upper 90(th) percentile when compared to a genome-wide distribution. However, for all population comparisons, F(ST) values decreased sharply in the 3' region of the gene. This pattern of differentiation among populations is consistent with selection in this part of the gene maintaining similar patterns of variation among otherwise divergent populations. Our results document not only different allele frequencies between populations, but differences in haplotype structure that may be important in evaluating association studies between hypertension and GRK4.

The purpose of this study was to ascertain coping styles among competitive athletes in response to various acute stressors. Specifically, the authors used a 134-item survey to measure approach and avoidance coping styles, with task-focused and emotion-focused coping tendencies nested hierarchically as subdimensions under each. Australian and U.S. college-aged participants indicated the extent to which they used approach, avoidance, task-focused, and emotion-focused coping strategies (a 4-factor model) in response to selected acute stressors experienced during sport competition. The authors computed confirmatory factor analysis to test the theoretically driven model. The criterion loading of .30 and above for each of the factors reduced the survey to 65 items. Findings indicated stronger links between the 2 approach constructs of task- and emotion-focused coping than between the 2 avoidance constructs of those subdimensions. The goodness-of-fit indices for the 4-factor model were 0.58 and 0.57 for Australian and U.S. samples, respectively, and .71 overall. Concomitant low correlations between the 2 approach (0.18) and the 2 avoidance dimensions (0.43) reflected relatively high residuals between stressors. In general, psychometric analyses suggest that coping style may be more prevalent in some situations than others, lending partial support for the transactional model of coping.

Samples taken from throughout the ranges of distribution of lodgepole pine (Pinus contorta Dougl. ex. Loud.) and jack pine (Pinus banksiana Lamb.) were assayed for Sal I and Sst I chloroplast DNA restriction fragment variation. Although the chloroplast genome is often regarded as highly conserved, at least 2 distinct Sal I and 13 distinct Sst I restriction fragment banding patterns occur in these closely related species. None of the chloroplast DNA restriction fragment banding patterns observed in allopatric lodgepole pine was observed in allopatric populations of jack pine, and vice versa, even though the two species share an extensive zone of sympatry, and gene flow between the species has been reported for nuclear genes. However, several atypical Sst I restriction fragment banding patterns occur only in or near the zone of sympatry. Chloroplasts have been reported to be inherited maternally in the great majority of species studied; however, restriction fragment analyses indicated that chloroplasts are inherited paternally in controlled matings between lodgepole pine (female) and jack pine (male).