6,162 research outputs found
Space station attitude disturbance arising from internal motions
A source of space station attitude disturbances is identified. The attitude disturbance is driven by internal space station motions and is a direct result of conservation of angular momentum. Three examples are used to illustrate the effect: a planar three link system, a rigid carrier body with two moveable masses, and a nonplanar five link system. Simulation results are given to show the magnitude of the attitude change in each example. Factors which accentuate or attenuate this disturbance effect are discussed
Comparison of life history parameters for landed and discarded fish captured off the southeastern United States
Commercial fisheries that are managed with minimum size limits protect small fish of all ages and may affect size-selective mortality by the differential removal of fast growing fish. This differential removal may decrease the average size at age, maturation, or sexual transition of the exploited population. When fishery-independent data are
not available, a comparison of life history parameters of landed with those of discarded fish (by regulation) will
indicate if differential mortality is occurring with the capture of young but large fish (fast growing phenotypes).
Indications of this differential size-selective mortality would include the following: the discarded portion of the target fish would have similar age ranges but smaller sizes at age, maturation, and sexual transition as that of landed fish. We examined three species with minimum size limits but different exploitation histories. The known heavily exploited species (Rhomboplites aurorubens [vermilion snapper] and Pagrus pagrus [red porgy]) show signs of this
differential mortality. Their landed catch includes many young, large fish, whereas discarded fish had a similar age range and mean ages but smaller sizes at age than the landed
fish. The unknown exploited species, Mycteroperca phenax (scamp), showed no signs of differential mortality due
to size-selective fishing. Landed catch consisted of old, large fish and discarded scamp had little overlap in age ranges, had significantly different mean ages, and only small differences in size at age when compared to comparable
data for landed fish
A Design for a Proposed Skill Proficiency Test in Tumbling and Apparatus for Male Physical Education Majors at the University of North Dakota
The purpose of this study was to design an instrument that would measure the tumbling and apparatus skill proficiency of male physical education majors of the University of North Dakota.
Two groups were used in the study. An experimental group of fifteen subjects, which was taking the required tumbling and apparatus course five times weekly; and a control group of ten subjects that had taken the same class the semester before, were utilized in this study.
The two groups were given the initial test for purposes of determining item validity. The experimental group was also given a retest to determine test item reliability.
Two statistical comparisons were made: (1) a within group comparison between the initial test and retest means given to the experimental group, and (2) a comparison between the means on the initial test of both groups in the areas tested. The null hypothesis was assumed in analyzing the significance of the difference between the means, of the within group comparison for reliability, at the .05 level. The .10 level of significance was used to determine item validity in the between group comparison.
The results of the within group comparison showed a significant difference in eight of the twenty-two items tested, and therefore these items were rejected. The between group comparison indicated six items to be significant.
It was concluded that the six items found statistically significant in both between group comparisons were reliable and valid test items for measuring tumbling and apparatus skill proficiency, fore, these test items made up the final test battery
A rapid equity focused health impact assessment of a policy implementation plan: An Australian case study and impact evaluation
<p>Abstract</p> <p>Background</p> <p>Equity focused health impact assessments (EFHIAs), or health equity impact assessments, are being increasingly promoted internationally as a mechanism for enhancing the consideration of health equity in the development of policies, programs and projects. Despite this there are relatively few examples of examples of completed EFHIAs available. This paper presents a case study of a rapid EFHIA that was conducted in Australia on a health promotion policy implementation plan. It briefly describes the process and findings of the EFHIA and evaluates the impact on decision-making and implementation.</p> <p>Methods</p> <p>The rapid EFHIA was undertaken in four days, drawing on an expert panel and limited review of the literature. A process evaluation was undertaken by email one month after the EFHIA was completed. An impact evaluation was undertaken two years later based on five semi-structured interviews with members of the EFHIA working group and policy officers and managers responsible for implementing the plan. A cost estimation was conducted by the EFHIA working group.</p> <p>Findings</p> <p>The EFHIA made both general and specific recommendations about how the health equity impacts of the policy implementation plan could be improved. The impact evaluation identified changes to development and implementation that occurred as a result of the EFHIA, though there was disagreement about the extent to which changes could be attributed solely to the EFHIA. Those responsible considered the recommendations of the EFHIA in the next versions of their ABHI implementation plans. Factors that influenced the impact of the EFHIA included consolidating understandings of equity, enabling discussion of alternatives, and differing understandings of the purpose of the EFHIA. The EFHIA cost US$4,036 to undertake.</p> <p>Conclusions</p> <p>This EFHIA was conducted in a short timeframe using relatively few resources. It had some reported impacts on the development of the implementation plan and enhanced overall consideration of health equity. This case highlights some of the factors and preconditions that may maximise the impact of future EFHIAs on decision-making and implementation.</p
On the Kauffman bracket skein module of the quaternionic manifold
We use recoupling theory to study the Kauffman bracket skein module of the
quaternionic manifold over Z[A,A^{-1}] localized by inverting all the
cyclotomic polynomials. We prove that the skein module is spanned by five
elements. Using the quantum invariants of these skein elements and the Z_2
homology of the manifold, we determine that they are linearly independent.Comment: corrected summation signs in figures 14, 15, 17. Other minor change
Evolutionary history of the Maltese wall lizard Podarcis filfolensis : insights on the 'expansion-contraction' model of Pleistocene biogeography
The expansion-contraction (EC) model predicts demographic and range contraction of temperate species during Pleistocene glaciations as a consequence of climate-related habitat changes, and provides a paradigm for explaining the high intraspecific diversity found in refugia in terms of long-term demographic stability. However, recent evidence has revealed a weak predictive power of this model for terrestrial species in insular and coastal settings. We investigated the Pleistocene EC dynamics and their evolutionary consequences on temperate species using the Maltese archipelago and its endemic lizard Podarcis filfolensis as a model system. The evolutionary and demographic history of P. filfolensis as inferred from mitochondrial and nuclear sequences data does not conform to the EC model predictions, supporting (i) demographic and spatial stability or expansion, rather than contraction, of the northern and southern lineages during the last glacial period; and (ii) a major role for allopatric differentiation primed by sea-level dynamics, rather than prolonged demographic stability, in the formation of the observed genetic diversity. When combined with evidence from other Mediterranean refugia, this study shows how the incorporation of Pleistocene sea-level variations in the EC model accounts for a reverse demographic and range response of insular and coastal temperate biotas relative to continental ones. Furthermore, this cross-archipelago pattern in which allopatric diversity is formed and shaped by EC cycles resembles that seen between isolated populations within mainland refugia and suggests that the EC model, originally developed to explain population fluctuations into and out-of refugia, may be appropriate for describing the demographic and evolutionary dynamics driving the high genetic diversity observed in these areas.peer-reviewe
Photometry and the Metallicity Distribution of the Outer Halo of M31
We have conducted a wide-field CCD-mosaic study of the resolved red-giant
branch (RGB) stars of M31, in a field located 20 kpc from the nucleus along the
SE minor axis. In our (I, V-I) color-magnitude diagram, RGB stars in the top
three magnitudes of the M31 halo are strongly present. Photometry of a more
distant control field to subtract field contamination is used to derive the
`cleaned' luminosity function and metallicity distribution function (MDF) of
the M31 halo field. From the color distribution of the foreground Milky Way
halo stars, we find a reddening E(V-I)= 0.10 +/- 0.02 for this field, and from
the luminosity of the RGB tip, we determine a distance modulus (m-M)_o = 24.47
+/- 0.12 (= 783 +/- 43 kpc). The MDF is derived from interpolation within an
extensive new grid of RGB models (Vandenberg et al. 2000). The MDF is dominated
by a moderately high-metallicity population ([m/H]~ -0.5) found previously in
more interior M31 halo/bulge fields, and is much more metal-rich than the
[m/H]~ -1.5 level in the Milky Way halo. A significant (~30% - 40%, depending
on AGB star contribution) metal-poor population is also present. To first
order, the shape of the MDF resembles that predicted by a simple,
single-component model of chemical evolution starting from primordial gas with
an effective yield y=0.0055. It strongly resembles the MDF recently found for
the outer halo of the giant elliptical NGC 5128 (Harris et al. 2000), though
NGC 5128 has an even lower fraction of low-metallicity stars. Intriguingly, in
both NGC 5128 and M31, the metallicity distribution of the globular clusters in
M31 does not match the halo stars; the clusters are far more heavily weighted
to metal-poor objects. We suggest similarities in the formation and early
evolution of massive, spheroidal stellar systems.Comment: to appear in the Astronomical Journal; 43 pages, including 15 figure
Juvenile Finfish And Blue Crab Stock Assessment Program Bottom Trawl Survey Annual Report Series Volume 1989
This report summarizes data collected by the Virginia· Institute of Marine Science (VIMS) trawl survey monthly cruises for January through December, 1989. The trawl survey is a long term, broad scope monitoring program. Its primary goal is to produce annual indices of juvenile (young-of-year) abundance of commercially, recreationally and ecologically important marine and estuarine finfish and crustaceans. The objective is to provide indices of sufficient accuracy and precision for both immediate resource management needs and long-term understanding of environmental influences on fishery resources. A second important product of this effort is the documentation and monitoring of habitat utilization by juveniles and smaller adults of these species. The program also provides a sound framework for the procurement of biological samples for life history studies and other concurrent scientific investigations relevant to fishery resource management
Zooplankton and Micronekton in Cyclones and Anticyclones in the Northeast Gulf of Mexico
Two cruises were made to the northeast Gulf of Mexico in October 1996 and August 1997. The main objectives of the cruises were to survey cetacean and seabird populations and describe their hydrographic and biological environments. An additional objective was to characterize cetacean and seabird habitats in terms of food resources. During both cruises a cyclone and an anticyclone were sampled as well as the confluence region between them. Zooplankton and micronekton were sampled both directly with nets and indirectly with a 153-kHz acoustic Doppler current profiler. Within cruises, zooplankton and micronekton biomass was higher in cyclones than in anticyclones. Biomass within the confluence was either highest or intermediate for both cruises. Between cruises, within features, August 1997 biomass was significantly higher than October 1996 biomass
Juvenile Finfish and Blue Crab Stock Assessment Program Bottom Trawl Survey annual data report series, volume 1991
This report presents a summary page for each tow conducted by the Virginia Institute of Marine Science, Juvenile Fish and Blue Crab Trawl Survey during 1991. The sampling methods and summarized data are presented in Bonzek et al. (1992). Data analysis and calculations of juvenile indices for selected species are presented in Colvocoresses et al. (1991). The purpose of this report is simply to provide a hard copy record of trawl results. It also provides a method to retrieve information about one or several particular trawls without consulting computerized archives. · · All data about each tow are presented, except that length data are summarized to number measured, minimum size, maximum size, mean size, and standard error. Each page contains four major subsections:: Station Data, Atmospheric and Hydrographic Data, Comments; and Catch Summa:ry Data. Each subsection is further divided into groups of related data, such as Station Identification Data or Atmospheric Data
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