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We measured the cytonuclear disequilibrium between 11 nuclear allozyme loci and both mitochondrial and chloroplast DNA haplotypes in a natural population of ponderosa pine (Pinus ponderosa, Laws). Three allozyme loci showed significant associations with mtDNA variation, while two other loci showed significant association with cpDNA. However, the absolute number of individuals involved in any of the associations was small, such that in none of the nuclear-organellar combinations was the difference between observed and expected numbers >11 individuals. Patterns of association were not consistent across loci or organellar genomes, suggesting that they are not the result of mating patterns, which would act uniformly on all loci. This pattern of disequilibria is consistent with the action of genetic drift and with existing knowledge of the structure of this population and thus does not imply the action of other evolutionary processes. The overall magnitude (normalized disequilibrium) of associations was greater for maternally inherited mtDNA than for paternally inherited cpDNA, though this difference was neither large nor significant. Such significant disequilibria involving the paternally inherited organelle indicate that not only are there a limited number of seed parents, but the effective number of pollen parents is also limited.

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Drainage systems of the Great Plains and western Gulf Slope underwent substantial changes through diversions and stream captures during the Pleistocene, either as the result of the glacial advances or through independent geologic processes. The distributions of a variety of fishes that range across west-central North America, such as the plains killifish (Fundulus zebrinus), are thought to be the product of this Pleistocene influence. We examined the geographic pattern of genetic variation in F. zebrinus using three allozyme loci (n = 793), mitochondrial DNA restriction fragment length polymorphisms (RFLPs, n = 352), and sequencing of the mitochondrial cytochrome oxidase I (COI, n = 23) in an attempt to understand the roles of dispersal and vicariance. The phylogeographic patterns were concordant between the allozyme and mitochondrial data with the exception of the population in the North Canadian River. The populations fell into three geographic assemblages, which we designated as northern, central, and southern. A large phylogenetic break (average Roger's D = 0.702; average sequence divergence in RFLPs = 4.6%; average sequence divergence in COI = 5.5%) separated the northern/central and southern assemblages. The northern region was likely colonized sometime during the mid-Pleistocene. Fish in the Brazos and Pecos Rivers probably reached these drainages through stream captures of the Red River. The large phylogenetic break between the northern/central and southern clades supports previous attempts to recognize two species of plains killifish: F. zebrinus and F. kansae.

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We performed an allozyme survey of genetic differentiation in Pinus balfouriana, a subalpine conifer endemic to California that is comprised of two allopatric subspecies, one in the Klamath Mountains and the other in the southern Sierra Nevada. Although the two subspecies are morphologically distinct and gene flow between them is virtually nonexistent, we observed much higher levels of differentiation among populations within a subspecies than between the two subspecies. Differentiation is particularly strong in the Klamath populations (multilocus FST = 0.242), which are small, isolated, and ecologically marginal. We attribute this strong differentiation to the mountain island effect, in which populations restricted to high elevations become isolated from each other on different mountains separated by unsuitable intervening habitat, with consequent reduced gene flow allowing populations to evolve independently. Populations of P. balfouriana in the Klamath region only exist scattered on the few highest ridges and peaks that rise above 2,000 m, which defines the lower limit of the species elevational distribution. This pattern of distribution has allowed genetic drift and allelic sorting through historical events to produce strong population-level differentiation, which was likely in place before the two subspecies were geographically separated. Because P. balfouriana occurs on both serpentine soils and nonserpentine soils in the Klamath Mountains, we tested for genetic differentiation between populations growing on serpentine versus nonserpentine soils and our results were equivocal. Our data, combined with several other studies of conifers, show that the mountain island effect can produce significant genetic differentiation in conifers whose life-history traits of widely dispersed pollen, long generation times, and high outcrossing rates would lead us to predict a more homogenous population genetic structure.

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South Africa (SA) now accounts for more than 50% of newly reported HIV cases in sub-Saharan Africa annually. In 1993, approximately 90% of those reported as HIV positive in SA were of African descent. This paper examines sociological factors in the spread of HIV in SA through the application of Lalonde's (1974) Health Field Concept. SA's emerging District Health System (DHS) is discussed, as well as barriers to effective implementation and recommendations. Through Lalonde's sociopolitical view of health, a coordinated and multisectorial approach to HIV/AIDS in SA can be established. Without this approach, health care interventions will fail to target the population effectively, thereby reducing effectiveness and sustainability.

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We investigated the relative importance of resource use and geography on genetic differentiation in the sister-species pair of generalist and specialist bark beetles: Dendroctonus ponderosae and D. jeffreyi (Coleoptera: Scolytidae). In two regions, where the distributions of these species overlap, we collected specimens of the generalist from multiple host species and specimens of the specialist from its single host species. Using allozyme techniques, we uncovered genetic differentiation between generalist populations on different host species in the same region (one locus in each region). However, a much stronger pattern of differentiation was found between specialist populations in the two distantly separated regions (three loci). With mtDNA, we found no significant differentiation between regions in the specialist, or among host species in the generalist, although there was some differentiation between regions in the generalist (AMOVA, P < 0.05). Overall, the generalist populations maintained approximately 10 times the genetic variation in mtDNA as the specialist populations, which suggests that the specialist either has generally smaller population sizes than the generalist, or has experienced a historical population bottleneck.

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This study provides empirical information on intrapopulation gene dispersal via pollen, the size of genetic 'neighbourhoods', and interpopulation gene flow in a long-lived conifer, limber pine (Pinus flexilis). We used allozyme loci for a paternity analysis of 518 seeds produced in an isolated population of limber pine located in north-eastern Colorado, U.S.A., separated by 2 km from the nearest conspecific trees and nearly 100 km from populations in the Rocky Mountains. We also used indirect techniques (FST analyses) to estimate gene flow rates among subdivisions of the study population and among five widely separated populations. Within the main study population limber pine exhibited a polymorphism level of 50%, observed heterozygosity of 0.159, and 2.36 alleles per polymorphic locus. Mountain populations were slightly more variable. The main study population showed significant differentiation in allozymes among neighbouring subpopulations. The mean FST was 0.031 and the gene flow rate among subpopulations was estimated as 7.8 migrants per generation. Among widely separated populations the mean FST was 0.035 and the gene flow rate was estimated as 6.9 migrants per generation. The paternity analysis indicated a best estimate of 6.5% pollen immigration (minimum 1.1%) from populations 2 km to 100+ km away. For 4% of the seeds examined, paternity could be ascribed to a single tree in the study population. Fractional paternity and likelihood methods were used to estimate pollen dispersal distances for the remainder of the seeds. Mean pollen dispersal distance was estimated at 140 m using the fractional method, similar to results from the other techniques. This compares with a mean distance of 172 m between potential mates. These results suggest near-panmictic pollen dispersal over this population, which covers about 15 ha. The observed allozyme differences and surprisingly low estimates of among-subpopulation gene flow are ascribed to a probable restriction of gene dispersal by seeds.

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To make inferences about the glacial refugia that harboured the limber pine, Pinus flexilis James, we examined the range-wide population structure of mitochondrial DNA (mtDNA) with eight size variants in the second intron of nad1. The data consisted of haplotypes from 704 trees collected from 40 localities. The value of FST for these populations was 0.80, which is a much larger value than has been reported for allozymes and chloroplast DNA (cpDNA) in limber pine, and it suggests that the number of seeds moving among localities per generation is approximately 0.12. Gene flow of this magnitude would allow mutation and subsequent genetic drift to have a substantial impact on the population structure of mtDNA. The majority of the mtDNA haplotypes are restricted to minor portions of the geographical range. The data are consistent with mtDNA differentiation in seven glacial refugia, followed by dispersal out of those refugia.

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Microgeographic allozyme variation was examined in pinyon pine, Pinus edulis, among five collection sites in Owl Canyon, Colorado. Relatively dry and moist sites were identified by associated plant communities and the sizes and densities of trees. Three moist sites and two dry sites were compared, and because all sites were within 600 m of one another, isolation by distance was not considered as a viable explanation of genetic differentiation between sites. Allelic frequencies at glycerate dehydrogenase (Gly) differed by 14% between moist and dry areas, and the pattern of microgeographic variation found here-allele 3 higher in frequency on dry sites-was consistent with previous studies of microgeographic variation in contrasting moist and dry sites. Trees within one of the dry sites were examined to test the hypothesis that stomata sizes and densities are heterogeneous among Gly genotypes. Heterozygotes had the longest and widest stomata; the stomatal area of heterozygotes was 28% greater than the stomatal area of homozygotes. Whereas the stomatal areas of the two homozygotes were similar, their shapes did not overlap when projected on a bivariate plot of length and width. These results suggest that stomatal shape may play a role in adapting pinyon to heterogeneity in soil moisture.

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We examined genetic differentiation among seven populations of limber pine using four classes of gene marker. Among-population differentiation was much higher for maternally inherited mitochondrial DNA polymorphisms than for paternally inherited chloroplast DNA, indicating that wind-dispersed pollen is the main agent of gene flow. Chloroplast DNA differentiation is consistent with gene flow estimated in a prior paternity analysis. Using the estimates of seed and pollen flow derived from mtDNA and cpDNA differentiation, we predicted the value of Fst expected at nuclear loci. Allelic frequency differentiation at seven allozyme loci was relatively homogeneous across loci and consistent with the level of differentiation predicted from the organellar haplotypes. By contrast four of the nine randomly applied polymorphic DNA (RAPD) markers we examined were more strongly differentiated than this prediction, suggesting the action of diversifying selection. However, the differentiated RAPDs and mtDNA were concordant in dividing the populations into two groups, suggesting some historical division. Simulations show that such historical division can increase the interlocus variance in Fst, but neither a historical nor an equilibrium model could account for the joint distribution of Fst estimates across both allozyme and RAPD loci. Thus at least one group of loci appears to be experiencing natural selection.

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Three surface methods for measuring lumbar sagittal motion (LSM) were tested for validity using radiographs as the "gold standard" reference. The three methods used were the Pleurimeter V double inclinometer, the carpenter double inclinometer, and the computerized sensor single inclinometer. In this study, 30 volunteers were examined independently by three occupational health professionals. Each volunteer rotated twice through three stations at which LSM was measured by each of the three methods. Radiographs were made during the first rotation. Predictability of the skin marks of T12 and S1 for the corresponding bone measures was acceptable for one examiner, mixed for another, and unacceptable for a third. The intraclass correlation coefficients (ICCs) ranged from 0.81 to 0.99, with half above the acceptable level of 0.90. However, the skin marks and the bone measures showed a linear relationship for all examiners (r > or = 0.89). For flexion and extension, all ICCs between the radiograph and each surface method were far below 0.90, indicating poor validity for each surface method. We concluded that skin placement of T12 and S1 has a linear relationship to bony landmarks, and that each of the tested surface methods does not validly measure LSM.

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Three surface methods for measuring lumbar sagittal motion (LSM) were tested for reliability. The three methods used were the Pleurimeter V double inclinometer, the carpenter double inclinometer, and the computerized single sensor inclinometer. In this study, 30 volunteers were examined independently by three occupational health professionals. Each volunteer rotated twice through three stations at which LSM was measured by each of the three methods. The intra- and interexaminer reliabilities in identifying the skin levels of T12 and S1 were acceptable, having intraclass correlation coefficients (ICC) greater than or equal to 0.75. With a single exception, all ICC values for the intraexaminer reliability of LSM measurements fell below 0.90 (a clinically desirable level). The interexaminer reliability was poor, with all ICC values below 0.75. The largest source of measurement error was attributable to the examiner and its associated factors. We concluded that the intra- and interexaminer reliabilities varied greatly, limiting the clinical usefulness of the three surface methods.

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Diagnostic length differences in a PCR amplified fragment of the gene for byssal adhesive protein were used to study the zoogeographic distribution of Mytilus galloprovincialis and M. trossulus along the west coast of North America and in Japan. The distributions of M. galloprovincialis and M. trossulus are patchy, although an overall geographic pattern emerges. M. galloprovincialis was the only species found on either Kyushu or Honshu, and it was the most abundant mussel from Tomales Bay to San Diego, California. M. trossulus was the only bay mussel found on Hokkaido and in Alaska, and it was by far the most abundant mussel along the coasts of Washington and Oregon. Mytilus galloprovincialis and M. trossulus are sympatric and hybridize near Whidbey Island, Washington, in San Francisco Bay, and in San Diego Bay. A second diagnostic anonymous nuclear PCR marker was used to examine the extent of hybridization at Palo Alto, California. At this site, genotypes appeared to be a mixture of M. galloprovincialis, F1 hybrids between M. galloprovincialis and M. trossulus, and backcrosses between the F1's and M. galloprovincialis. The discontinuity between the zoogeographic distributions of these two species at about 40{deg}-41{deg}N latitude in both the eastern and western Pacific suggests that temperature is a factor in determining their present distribution and limiting their dispersal to other regions.

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This prospective cohort study of patients with borderline psychopathology reports on the clinical disorders occurring during the course and at 7-year follow-up. Subjects with persistent versus remitted borderline personality disorder (BPD) are compared. The relationship between the initial levels of borderline psychopathology and the occurrence of clinical disorders on follow-up is examined. Consecutive admissions to inpatient units were screened for borderline characteristics. This resulted in a sample of 130 subjects, 88 of whom were positive for BPD based on the Diagnostic Interview for Borderlines. At 7-year follow-up, 81 (62.3%) subjects were reinterviewed in person, 6 (4.6%) suicided, 2 (1.6%) were decreased, 36 (27.7%) refused to participate, and 5 (3.8%) could not be located. Twenty-seven of 57 (47.4%) who initially were positive for BPD were rediagnosed at 7-year follow-up (the persistent group) and 30 (52.6%) were no longer diagnosed as BPD (the remitted group). The persistent individuals were significantly more likely to be diagnosed as having major depression, dysthymia, and other psychiatric disorders than the remitted group. The persistent group had significantly more episodes of substance abuse over the follow-up period compared with the remitted group. Individuals with persistent BPD suffered more episodes of clinical disorders over the follow-up period and the initial level of borderline psychopathology predicted the recurrence of major depression.

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The objective of this paper was to examine the prognostic significance of borderline personality disorder (BPD) and substance abuse in a cohort of former inpatients screened for BPD and followed up prospectively seven years after the index admission. The impact of comorbidity on borderline psychopathology, impulsivity and psychosocial functioning was examined. The original cohort was assembled between April 1983 and December 1985. Admissions were screened for borderline characteristics which resulted in a sample of 130 subjects, 88 of whom were positive for BPD based on the Diagnostic Interview for Borderlines. At seven years follow-up, 81 out of 130 (62.3%) subjects were re-interviewed. Six (4.6%) had committed suicide, two (1.5%) were deceased and 41 (31.6%) were lost to follow-up. The subjects with BPD and substance abuse were significantly differentiated from subjects with BPD only, substance abuse only and neither disorder on the basis of demonstrating more borderline psychopathology and more self-destructive and suicidal thoughts and behaviours. Probands with initial diagnoses of BPD and substance abuse were twice as likely to be diagnosed BPD on follow-up as probands with initial diagnosis of BPD only (relative risk = 2.19, 95% CI, 1.21 to 3.97). These findings and other research suggest that patients with comorbid BPD and substance abuse should be encouraged to focus on their abuse problems as a priority.

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Associations between genetic variation at four enzyme polymorphisms and growth rate, feed conversion and economic index were studied in commercial lines of pigs. These lines were also tested for the fit of observed genotypic frequencies to expected genotypic frequencies at the four polymorphic loci. Genotypic distribution fit Hardy-Weinberg expectations in four pure-breeding lines but crosses among lines produced excesses in heterozygosity at the locus coding for 6-phosphogluconate dehydrogenase (6PGD) due to differences in allelic frequencies among lines. Selection of breeding individuals further enhanced the heterozygosity at 6PGD to 73-93 per cent but it had no impact on a linked locus that was sometimes in linkage disequilibrium with 6PGD. The relationship between feed conversion and individual heterozygosity was examined in one population sample; feed conversion increased with individual heterozygosity.

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Specific formulations are derived for the correlation between the heterozygosity of a randomly mating parent and its offspring for a diallelic locus, and for the correlation when multiple loci are considered. The expected correlation is maximal, approaching r = 0.50, when allelic frequencies are highly asymmetric, and it is zero when the allelic frequencies are equal to 0.50. Parent-offspring correlations, up to a maximum of 0.50 for diallelic loci, indicate that levels of heterozygosity can respond to selection. Multilocus allozyme data from limber pine, Pinus flexilis, and from horses of standardbred and thoroughbred breeds are used to demonstrate correlations between a parent and its offspring. The Spearman rank correlation between the heterozygosity of a limber pine and the mean heterozygosity of her offspring is r = 0.45. Correlations in the horses range from r = 0.16 to 0.32.

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This study reports the first data to be published on the timing of self-repairs in spontaneous speech, giving means and confidence intervals for cut-off-to-repair, error-to-repair, and cut-off-to-repair times for different types of repair based on 1525 repairs made in the conversational turns of 61 callers to a radio talk show. The three most detailed models of monitoring are discussed in the introduction, with emphasis on their temporal implications. Many of the cut-off-to-repair times observed were faster than would be predicted by any model in the literature. Laver's (1980) theory of monitoring is shown to be incongruent with the observed times, as is Levelt's (1983, 1989) main interruption rule. The results show that people can plan corrections to their speech while talking, and suggest that Kempen and Hoenkamp's (1987) concept of incremental processing can be extended to repairs.

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The purpose of this study is to identify variables predictive of the psychosocial outcomes of borderline patients 2 years following an acute psychiatric hospitalization. Of the initial 88 inpatients scoring positive for the Diagnostic Interview for Borderlines (DIB), 65 (73.8%) were reinterviewed, 14 (15.9%) refused, five (5.7%) were unable to be located, and four (4.6%) suicided. The dropouts (n = 19) were significantly more likely to be single, separated, or divorced, to be male, and to be diagnosed as having co-existing antisocial personality disorder than the followed-up probands (n = 69). In terms of global functioning, over the 2-year follow-up period, 61 (87.7%) of the 69 probands were judged to be functioning normally less than 50% of the follow-up interval. Using logistic regression, two variables, initial impulse action scores and poor premorbid functioning, predicted poor versus good outcome. This study supports the literature, which indicates that the early course of borderline personality disorder (BPD) is stormy. Impulsivity and poor premorbid functioning may be predictive of poor short-term outcome in borderline patients.

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Comparing a sample of 88 inpatients with borderline personality disorder (BPD) to inpatients with borderline traits, this paper addresses four hypotheses regarding the association between BPD and psychotic symptoms: (1) narrowly defined psychotic symptoms are rare in BPD; (2) broadly defined psychotic symptoms are often reported in BPD; (3) narrowly defined psychotic symptoms are due to concomitant disorders, and (4) psychotic symptoms may be factitious. Consecutive admissions to acute inpatient services were screened for borderline features and patients were examined using the Diagnostic Interview for Borderlines and the Schedule for Affective Disorders and Schizophrenia. The results generally supported the proposed explanations for the association between BPD and psychotic symptoms. Factitious psychotic symptoms were found in only 13% of the BPD sample.

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