8,043 research outputs found
Effect of pig weaning age and commingling after the nursery phase on humoral and behavioral indicators of well-being and on growth performance
Two hundred and sixteen pigs were weaned at 14 or 21 d of age to determine the effect of weaning age and commingling after the nursery phase on growth and behavior of pigs in a wean-tofinish facility. Pigs were divided into older and younger age groups and allotted 12 pigs/pen with nine replications of each group. At the end of the nursery phase (d 34 after weaning), one-half of the pigs in each group were removed and commingled for the grower/finisher phase and the other half remained in their original pens. Beginning at weaning (d 0), pigs were monitored via camera surveillance following weaning, commingling, and on d 65 after weaning. While in the nursery phase, older pigs had greater gain and feed intake than younger pigs, however, younger pigs were more efficient throughout the nursery phase than older pigs. Toward the end of the grower/finisher period, younger pigs had greater gain, feed intake, and gain:feed than older pigs and reached a common weight 4 d sooner. Younger pigs spent more time standing or moving during the nursery phase than older pigs. Immediately following commingling, the younger, unmixed pigs spent more time feeding. However on d 65 after weaning, the older, commingled pigs and younger, unmixed pigs spent more time feeding than older, unmixed pigs and younger, commingled pigs. In conclusion, younger pigs grew slower than older pigs during the nursery phase; however, younger pigs gained more during the finishing period. Additionally, weaning age and commingling influenced feeding behavior during the grower/finisher period
Comparison of the USGS 2001 NLCD to the 2002 USDA Census of Agriculture for the Upper Midwest United States
The U.S. Geological Survey (USGS) 2001 National Land Cover Database (NLCD) was compared to the U.S. Department of Agriculture (USDA) 2002 Census of Agriculture. Wecompared areal estimates for cropland at the state and county level for 14 States in the Upper Midwest region of the United States. Absolute differences between the NLCD and Census cropland areal estimates at the state level ranged from 1.3% (Minnesota) to 37.0% (Wisconsin). The majority of counties (74.5%) had differences of less than 100 km2. 7.2% of the counties had differences of more than 200 km2. Regions where the largest areal differences occurred were in southern Illinois, North Dakota, South Dakota, and Wisconsin, and generally occurred in areas with the lowest proportions of cropland (i.e., dominated by forest or grassland). Before using the 2001 NLCD for agricultural applications, such as mapping of specific crop types, users should be aware of the potential for misclassification errors, especially where the proportion of cropland to other land cover types is fairly lo
Water Analysis of the Malibu Lagoon and Pacific Ocean
This experiment tested the waters of the Malibu Lagoon and the Pacific ocean to compare levels of E.coli. We hypothesized that greater amount of E.coli would be present in the waters of the Malibu Lagoon. Because of the runoff and pollution existing in the lagoon, we predicted that higher levels of this bacteria would be found there. This study is significant because many organisms living in these waters can be negatively effected by large levels of E.coli. We used the most probable number method to determine the amounts of bacteria. A collection of samples from three testing sites in both the lagoon and the ocean were taken, then added to a red phenol lactose broth and incubated to determine the amount of E.coli present in each of the samples. Resulting data supported our hypothesis, providing evidence that a greater amount of E.coli existed in the Malibu lagoon in comparison to the Pacific ocean
Stick boundary conditions and rotational velocity auto-correlation functions for colloidal particles in a coarse-grained representation of the solvent
We show how to implement stick boundary conditions for a spherical colloid in
a solvent that is coarse-grained by the method of stochastic rotation dynamics.
This allows us to measure colloidal rotational velocity auto-correlation
functions by direct computer simulation. We find quantitative agreement with
Enskog theory for short times and with hydrodynamic mode-coupling theory for
longer times. For aqueous colloidal suspensions, the Enskog contribution to the
rotational friction is larger than the hydrodynamic one when the colloidal
radius drops below 35nm.Comment: new version with some minor change
Morphometric characterization of three Tsetse Fly Species - Glossina M. Morsitans, G. P. Palpalis and G. Tachinoides (Diptera: Glossinidae) from Ghana
Tsetse flies (Diptera: Glossinidae) are the main vectors of Human African Trypanosomiasis (HAT), or sleeping sickness and Animal African Trypanosomiasis, (AAT) or Nagana in Sub Saharan Africa. In Ghana, whilst HAT is no longer a major public health issue, AAT is still widely reported and causes considerable losses in the livestock sector resulting in major impacts on agricultural production, livelihoods and food security in the country.
Application of morphometric techniques can reveal the existing level of population differentiation in tsetse flies, providing guidance on the distribution of genetically defined subpopulations. Morphometric techniques were used to compare size and shape of three tsetse fly species- G. m. morsitans, G. p. palpalis and G. tachinoides of Ghana, and also compare populations of G. p. palpalis collected from three geographical regions (Northern, Eastern and Western) of Ghana.
Flies were sampled from four sites in the Western, one site in the Eastern and three sites in the Northern Region using standard un-baited biconical traps. Right wings and right hind legs of selected flies from different collection sites were removed and mounted on microscope slides using glycerin as the mounting medium. Images of the prepared slides were captured under a Leica EZ4 D microscope with an inbuilt camera connected to a laptop.
Linear and proportions of wing and hind tibia measurements were arcsine-root transformed before analyzing with a general linear model in analysis of variance (ANOVA). Multivariate statistical analyses were used to detect any possible variations.
Results of the GLM analyses of linear and ratio data revealed that different linear combinations can be used to characterize tsetse species of different populations. The ratio value hind tibia/wing length (th/at) significantly distinguished fly populations into four groups, Northern, Eastern, Western and the lab colony; this is an indication that hind tibia/wing length is a good morphometric feature which can be used to discriminate flies from different regions of Ghana.
The principal components and canonical variates as well as Mahalanobis squared distances confirmed linear and ratio separations. Therefore based on these differences in morphometric characters observed, the three tsetse species were distinguished from each other.
Similar work on morphometrics needs to be done to include more regions and many other body parts such as proboscis length, antennal length, thorax and abdomen length and width in order to establish stronger morphometric tools for discriminating different tsetse fly species
Relaxation dynamics and colossal magnetocapacitive effect in CdCr2S4
A thorough investigation of the relaxational dynamics in the recently
discovered multiferroic CdCr2S4 showing a colossal magnetocapacitive effect has
been performed. Broadband dielectric measurements without and with external
magnetic fields up to 10 T provide clear evidence that the observed
magnetocapacitive effect stems from enormous changes of the relaxation dynamics
induced by the development of magnetic order.Comment: 4 pages, 4 figure
Large marine protected areas represent biodiversity now and under climate change
Large marine protected areas (>30,000 km2) have a high profile in marine conservation, yet their contribution to conservation is contested. Assessing the overlap of large marine protected areas with 14,172 species, we found large marine protected areas cover 4.4% of the ocean and at least some portion of the range of 83.3% of the species assessed. Of all species within large marine protected areas, 26.9% had at least 10% of their range represented, and this was projected to increase to 40.1% in 2100. Cumulative impacts were significantly higher within large marine protected areas than outside, refuting the critique that they only occur in pristine areas. We recommend future large marine protected areas be sited based on systematic conservation planning practices where possible and include areas beyond national jurisdiction, and provide five key recommendations to improve the long-term representation of all species to meet critical global policy goals (e.g., Convention on Biological Diversity's Aichi Targets
Development of three dimensional constitutive theories based on lower dimensional experimental data
Most three dimensional constitutive relations that have been developed to
describe the behavior of bodies are correlated against one dimensional and two
dimensional experiments. What is usually lost sight of is the fact that
infinity of such three dimensional models may be able to explain these
experiments that are lower dimensional. Recently, the notion of maximization of
the rate of entropy production has been used to obtain constitutive relations
based on the choice of the stored energy and rate of entropy production, etc.
In this paper we show different choices for the manner in which the body stores
energy and dissipates energy and satisfies the requirement of maximization of
the rate of entropy production that leads to many three dimensional models. All
of these models, in one dimension, reduce to the model proposed by Burgers to
describe the viscoelastic behavior of bodies.Comment: 23 pages, 6 figure
Signs of low frequency dispersions in disordered binary dielectric mixtures (50-50)
Dielectric relaxation in disordered dielectric mixtures are presented by
emphasizing the interfacial polarization. The obtained results coincide with
and cause confusion with those of the low frequency dispersion behavior. The
considered systems are composed of two phases on two-dimensional square and
triangular topological networks. We use the finite element method to calculate
the effective dielectric permittivities of randomly generated structures. The
dielectric relaxation phenomena together with the dielectric permittivity
values at constant frequencies are investigated, and significant differences of
the square and triangular topologies are observed. The frequency dependent
properties of some of the generated structures are examined. We conclude that
the topological disorder may lead to the normal or anomalous low frequency
dispersion if the electrical properties of the phases are chosen properly, such
that for ``slightly'' {\em reciprocal mixture}--when , and
--normal, and while for ``extreme'' {\em reciprocal
mixture}--when , and --anomalous
low frequency dispersions are obtained. Finally, comparison with experimental
data indicates that one can obtain valuable information from simulations when
the material properties of the constituents are not available and of
importance.Comment: 13 pages, 7 figure
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