Feeding Habits of Young-of-Year Striped Bass Morone saxatilis, and White Perch, Morone american in lower James River, VA

A total of 188 young-of-year (YOY) striped bass, Marone saxatilis, and 199 YOY white perch, Marone americana, were collected by pushnet, seine and trawl during 24-hour periods from June through August, 1992 in lower James River, Virginia. The purpose was to identify prey and temporal and spatial feeding habits. Copepods were the most numerous prey of both species. Fishes and mysids comprised the largest volumetnc percentage of diets of striped bass and white perch, respectively. Using an index of relative importance, leptodorids and copepods were the most important prey of striped bass and white perch, respectively. Botl1 species shifted from planktonic to epibenthic foods with increasing length. Diets of striped bass and white perch captured by seine were significantly more diverse than those captured by trawl. No temporal or spatial differences in feeding success were found for striped bass. White perch captured at twilight and by pushnet fed more successfully than conspecifics captured at day, or by seine or trawl, respectively. Spearman correlation coefficient, Horn\u27s index and Shannon-Weaver index indicated that diets between striped bass and white perch were significantly correlated, highly overlapping and equally diverse, respectively. With the exception of one temporal and one spatial comparison, interspecific comparisons of feeding success were not significantly different. Results indicate tlrnt young of both species feed opportunistically. Abiotic factors appear to have little direct relationship with YOY striped bass and YOY white perch feeding success

Feeding Habits of Young-of-Year Striped Bass, Morone saxatilis, and White Perch, Morone americana, in Lower James River, VA

A total of 188 young-of-year (YOY) striped bass, Morone saxatilis, and 199 YOY white perch, Morone americana, were collected by pushnet, seine and trawl during 24-hour periods from June through August, 1992 in lower James River, Virginia. The purpose was to identify prey and temporal and spatial feeding habits. Copepods were the most numerous prey of both species. Fishes and mysids comprised the largest volumetric percentage of diets of striped bass and white perch, respectively. Using an index of relative importance, leptodorids and copepods were the most important prey of striped bass and white perch, respectively. Both species shifted from planktonic to epibenthic foods with increasing length. Diets of striped bass and white perch captured by seine were significantly more diverse than those captured by trawl. No temporal or spatial differences in feeding success were found for striped bass. White perch captured at twilight and by pushnet fed more successfully than conspecifics captured at day, or by seine or trawl, respectively. Spearman correlation coefficient, Horn\u27s index and Shannon-Weaver index indicated that diets between striped bass and white perch were significantly correlated, highly overlapping and equally diverse, respectively. With the exception of one temporal and one spatial comparison, interspecific comparisons of feeding success were not significantly different. Results indicate that young of both species feed opportunistically. Abiotic factors appear to have little direct relationship with YOY striped bass and YOY white perch feeding success

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

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

Optimization of a Langmuir-Taylor detector for lithium

This paper describes the construction and optimization of a Langmuir-Taylor detector for lithium, using a rhenium ribbon. The absolute detection probability of this very sensitive detector is measured and the dependence of this probability with oxygen pressure and surface temperature is studied. Sources of background signal and their minimization are also discussed in details. And a comparison between our data concerning the response time of the detector and literature values is given. A theoretical analysis has been made: this analysis supports the validity of the Saha-Langmuir law to relate the ionization probability to the work function. Finally, the rapid variations of the work function with oxygen pressure and temperature are explained by a chemical equilibrium model.Comment: 11 pages, 7 figures, to appear in Rev. Sci. Instru

Corn, 1966

Cover title

Integrable Boundaries, Conformal Boundary Conditions and A-D-E Fusion Rules

The $sl(2)$ minimal theories are labelled by a Lie algebra pair $(A,G)$ where $G$ is of $A$-$D$-$E$ type. For these theories on a cylinder we conjecture a complete set of conformal boundary conditions labelled by the nodes of the tensor product graph $A\otimes G$. The cylinder partition functions are given by fusion rules arising from the graph fusion algebra of $A\otimes G$. We further conjecture that, for each conformal boundary condition, an integrable boundary condition exists as a solution of the boundary Yang-Baxter equation for the associated lattice model. The theory is illustrated using the $(A_4,D_4)$ or 3-state Potts model.Comment: 4 pages, REVTe

Microwave traps for cold polar molecules

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

The Familial Clustering of Age at Menarche in Extended Twin Families

The timing of puberty is complex, possibly involving many genetic factors that may interact with environmental influences. Familial resemblance for age at menarche was studied in a sample of 4,995 female twins, 1,296 sisters, 2,946 mothers and 635 female spouses of male twins. They had indicated their age at menarche as part of a larger longitudinal survey. We assessed assortative mating for age at menarche, gene–environment interaction effects and estimated the heritability of individual differences in pubertal timing. There was significant evidence of gene–environment interaction, accounting for 1.5% of the variance. There was no indication of consistent mate assortment on age at menarche. Individual differences in age at menarche are highly heritable, with additive genetic factors explaining at least 70% of the true variation. An additional 1.5% of the variation can be explained by a genotype–environment interaction effect where environmental factors are more important in individuals genetically predisposed for late menarche

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

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

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