454 research outputs found

    The Effect of Tropical Storm Agnes on Oysters, Hard Clams, Soft Clams, and Oyster Drills in VIrginia

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    Tropical Storm Agnes had a major effect on the molluscan fisheries of Virginia. One effect was the direct mortality of oysters, Crassostrea virginiaa, in the upper parts of many estuaries. Typical losses on leased bottoms were: the James River, 10%; the York River, 2%; the Rappahannock River, 50%; and the Potomac River tributaries (Virginia) 70%. Economic loss was in excess of 7.9 million dollars. There was a nearly complete absence of oyster larvae attachment (setting) in 1972. Other effects of Agnes included a nearly complete loss of soft clams, Mya arenaria, in the Rappahannock River. Hard clams, Meraenaria meraenaria, were killed in the upper part of the York River. Oyster drills, Urosalpinx ainerea, were eliminated from the Rappahannock and reduced greatly in numbers in the York and James Rivers.https://scholarworks.wm.edu/vimsbooks/1074/thumbnail.jp

    Microwave traps for cold polar molecules

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    We discuss the possibility of trapping polar molecules in the standing-wave electromagnetic field of a microwave resonant cavity. Such a trap has several novel features that make it very attractive for the development of ultracold molecule sources. Using commonly available technologies, microwave traps can be built with large depth (up to several Kelvin) and acceptance volume (up to several cm^3), suitable for efficient loading with currently available sources of cold polar molecules. Unlike most previous traps for molecules, this technology can be used to confine the strong-field seeking absolute ground state of the molecule, in a free-space maximum of the microwave electric field. Such ground state molecules should be immune to inelastic collisional losses. We calculate elastic collision cross-sections for the trapped molecules, due to the electrical polarization of the molecules at the trap center, and find that they are extraordinarily large. Thus, molecules in a microwave trap should be very amenable to sympathetic and/or evaporative cooling. The combination of these properties seems to open a clear path to producing large samples of polar molecules at temperatures much lower than has been possible previously.Comment: 10 pages, 3 figure

    Inheritance of Resistance to the First and Second Broods of the European Corn Borer in Corn

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    The European corn borer is one of the most destructive insect pests of corn. Our objective was to determine the inheritance of host resistance in corn to the first and second broods of the European corn borer with Design III and S1 progeny analyses. All estimates of additive and dominance genetic variances were significantly different from zero except for the dominance variance for second-brood cavity counts. Additive genetic variance, however, was the major component of the total genotypic variance in the F2 population for all traits. Average level of dominance was in the partial range for the date of anthesis (0.74), first-brood leaf feeding (0.81), and second-brood cavity counts (0.53), but in the range for complete dominance (1.09) for the second-brood visual rating. Some genes have dominance action in conditioning resistance to first and second broods of the European corn borer. Selection procedures that emphasize selection for additive genetic variance in the population for first- and second-brood larval feeding resistance would be effective for improving host resistance

    Daily Patterns of River Herring (\u3cem\u3eAlosa\u3c/em\u3e spp.) Spawning Migrations: Environmental Drivers and Variation among Coastal Streams in Massachusetts

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    The timing of life history events in many plants and animals depends on the seasonal fluctuations of specific environmental conditions. Climate change is altering environmental regimes and disrupting natural cycles and patterns across communities. Anadromous fishes that migrate between marine and freshwater habitats to spawn are particularly sensitive to shifting environmental conditions and thus are vulnerable to the effects of climate change. However, for many anadromous fish species the specific environmental mechanisms driving migration and spawning patterns are not well understood. In this study, we investigated the upstream spawning migrations of river herring Alosa spp. in 12 coastal Massachusetts streams. By analyzing long-term data sets (8–28 years) of daily fish counts, we determined the local influence of environmental factors on daily migration patterns and compared seasonal run dynamics and environmental regimes among streams. Our results suggest that water temperature was the most consistent predictor of both daily river herring presence–absence and abundance during migration. We found inconsistent effects of streamflow and lunar phase, likely due to the anthropogenic manipulation of flow and connectivity in different systems. Geographic patterns in run dynamics and thermal regimes suggest that the more northerly runs in this region are relatively vulnerable to climate change due to migration occurring later in the spring season, at warmer water temperatures that approach thermal maxima, and during a narrower temporal window compared to southern runs. The phenology of river herring and their reliance on seasonal temperature patterns indicate that populations of these species may benefit from management practices that reduce within-stream anthropogenic water temperature manipulations and maintain coolwater thermal refugia

    A solution to limitations of cognitive testing in children with intellectual disabilities: the case of fragile X syndrome

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    Intelligence testing in children with intellectual disabilities (ID) has significant limitations. The normative samples of widely used intelligence tests, such as the Wechsler Intelligence Scales, rarely include an adequate number of subjects with ID needed to provide sensitive measurement in the very low ability range, and they are highly subject to floor effects. The IQ measurement problems in these children prevent characterization of strengths and weaknesses, poorer estimates of cognitive abilities in research applications, and in clinical settings, limited utility for assessment, prognosis estimation, and planning intervention. Here, we examined the sensitivity of the Wechsler Intelligence Scale for Children (WISC-III) in a large sample of children with fragile X syndrome (FXS), the most common cause of inherited ID. The WISC-III was administered to 217 children with FXS (age 6–17 years, 83 girls and 134 boys). Using raw norms data obtained with permission from the Psychological Corporation, we calculated normalized scores representing each participant’s actual deviation from the standardization sample using a z-score transformation. To validate this approach, we compared correlations between the new normalized scores versus the usual standard scores with a measure of adaptive behavior (Vineland Adaptive Behavior Scales) and with a genetic measure specific to FXS (FMR1 protein or FMRP). The distribution of WISC-III standard scores showed significant skewing with floor effects in a high proportion of participants, especially males (64.9%–94.0% across subtests). With the z-score normalization, the flooring problems were eliminated and scores were normally distributed. Furthermore, we found correlations between cognitive performance and adaptive behavior, and between cognition and FMRP that were very much improved when using these normalized scores in contrast to the usual standardized scores. The results of this study show that meaningful variation in intellectual ability in children with FXS, and probably other populations of children with neurodevelopmental disorders, is obscured by the usual translation of raw scores into standardized scores. A method of raw score transformation may improve the characterization of cognitive functioning in ID populations, especially for research applications

    Individual differences in puberty onset in girls: Bayesian estimation of heritabilities and genetic correlations

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    We report heritabilities for individual differences in female pubertal development at the age of 12. Tanner data on breast and pubic hair development in girls and data on menarche were obtained from a total of 184 pairs of monozygotic and dizygotic twins. Genetic correlations were estimated to determine to what extent the same genes are involved in different aspects of physical development in puberty. A Bayesian estimation approach was taken, using Markovchain Monte Carlo simulation to estimate model parameters. All three phenotypes were to a significant extent heritable and showed high genetic correlations, suggesting that a common set of genes is involved in the timing of puberty in general. However, gonadarche (menarche and breast development) and adrenarche (pubic hair) are affected by different environmental factors, which does not support the three phenotypes to be regarded as indicators of a unitary physiological factor. © 2006 Springer Science+Business Media, Inc

    Testing the FMR1 Promoter for Mosaicism in DNA Methylation among CpG Sites, Strands, and Cells in FMR1-Expressing Males with Fragile X Syndrome

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    Variability among individuals in the severity of fragile X syndrome (FXS) is influenced by epigenetic methylation mosaicism, which may also be common in other complex disorders. The epigenetic signal of dense promoter DNA methylation is usually associated with gene silencing, as was initially reported for FMR1 alleles in individuals with FXS. A paradox arose when significant levels of FMR1 mRNA were reported for some males with FXS who had been reported to have predominately methylated alleles. We have used hairpin-bisufite PCR, validated with molecular batch-stamps and barcodes, to collect and assess double-stranded DNA methylation patterns from these previously studied males. These patterns enable us to distinguish among three possible forms of methylation mosaicism, any one of which could explain FMR1 expression in these males. Our data indicate that cryptic inter-cell mosaicism in DNA methylation can account for the presence of FMR1 mRNA in some individuals with FXS

    Autoimmune disease in mothers with the FMR1 premutation is associated with seizures in their children with fragile X syndrome

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    An increased prevalence of autoimmune diseases in family members of children with autism spectrum disorders (ASD) has been previously reported. ASD is also a common problem co-occurring in children with fragile X syndrome (FXS). Why ASD occurs in some individuals with FXS, but not all, is largely unknown. Furthermore, in premutation carrier mothers, there is an increased risk for autoimmune diseases. This study compared the rate of ASD and other neurodevelopmental/behavioral problems in 61 children with FXS born to 41 carrier mothers who had autoimmune disease and in 97 children with FXS of 78 carrier mothers who did not have autoimmune disease. There were no significant differences in the mean age (9.61 ± 5.59 vs. 9.41 ± 6.31, P = 0.836), cognitive and adaptive functioning in children of mothers with and without autoimmune disease. Among children whose mothers had autoimmune disease, the odds ratio (OR) for ASD was 1.27 (95% CI 0.62–2.61, P = 0.5115). Interestingly, the OR for seizures and tics was 3.81 (95% CI 1.13–12.86, P = 0.031) and 2.94 (95% CI 1.19–7.24, P = 0.019), respectively, in children of mothers with autoimmune disease compared to children of mothers without autoimmune disease. In conclusion, autoimmune disease in carrier mothers was not associated with the presence of ASD in their children. However, seizures and tics were significantly increased in children of mothers with autoimmune disease. This suggests a potential new mechanism of seizure and tic exacerbation in FXS related to an intergenerational influence from autoimmunity in the carrier mother

    Increased endothelin-1 in colorectal cancer and reduction of tumour growth by ET A receptor antagonism

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    Endothelin-1 (ET-1) is a vasoconstrictor peptide which stimulates proliferation in vitro in different cell types, including colorectal cancer cells. Raised ET-1 levels have been detected both on tissue specimens and in the plasma of patients with cancers. To investigate the role of ET-1 in colorectal cancer: (i) ET-1 plasma levels in patients with colorectal cancer were measured by radioimmunoassay: group 1 = controls (n = 22), group 2 = primary colorectal cancer only (n = 39), group 3 = liver metastases only (n = 26); (ii) ET-1 expression in primary colorectal cancer specimens (n =10) was determined immunohistochemically and (iii) the effect of intraportally infused antagonists to the two ET-1 receptors, ET A and ET B, on the growth of liver metastases in a rat model was assessed. ET-1 plasma levels were significantly increased in both patients with primary tumour and patients with metastases, compared to controls (P < 0.01, 3.9 ± 1.4, 4.5 ± 1.5, vs. 2.75 ± 1.37 pg/ml, respectively). Immunohistochemically, strong expression of ET-1 was found in the cytoplasm, stroma and blood vessels of cancers, unlike the normal colon where only the apical layer of the epithelium, vascular endothelial cells and surrounding stroma were positively stained. In the rat model, there was significant reduction in liver tumour weights compared to controls, following treatment with the ET A antagonist (BQ123) 30 min after the intraportal inoculation of tumour cells (P < 0.05). These results suggest ET-1 is produced by colorectal cancers and may play a role in the growth of colorectal cancer acting through ET A receptors. ET A antagonists are indicated as potential anti-cancer agents. © 2001 Cancer Research Campaign http://www.bjcancer.co

    Teasing apart the heterogeneity of autism: Same behavior, different brains in toddlers with fragile X syndrome and autism

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    To examine brain volumes in substructures associated with the behavioral features of children with FXS compared to children with idiopathic autism and controls. A cross-sectional study of brain substructures was conducted at the first time-point as part of an ongoing longitudinal MRI study of brain development in FXS. The study included 52 boys between 18–42 months of age with FXS and 118 comparison children (boys with autism-non FXS, developmental-delay, and typical development). Children with FXS and autistic disorder had substantially enlarged caudate volume and smaller amygdala volume; whereas those children with autistic disorder without FXS (i.e., idiopathic autism) had only modest enlargement in their caudate nucleus volumes but more robust enlargement of their amygdala volumes. Although we observed this double dissociation among selected brain volumes, no significant differences in severity of autistic behavior between these groups were observed. This study offers a unique examination of early brain development in two disorders, FXS and idiopathic autism, with overlapping behavioral features, but two distinct patterns of brain morphology. We observed that despite almost a third of our FXS sample meeting criteria for autism, the profile of brain volume differences for children with FXS and autism differed from those with idiopathic autism. These findings underscore the importance of addressing heterogeneity in studies of autistic behavior
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