3,554 research outputs found
Climate Change and Migration: The Intersection of Climate Change, Migration, and Gender through Policy
This article explores the intersectional nature of the issue of climate change, especially as it relates to migration. Both migration and climate change are issues of global significance, with benefits and burdens distributed unevenly across gender, racial, and class lines. This intersectional approach takes note of the unequal power structures at play when attempting to combat these issues with policy
Accelerated battery-life testing - A concept
Test program, employing empirical, statistical and physical methods, determines service life and failure probabilities of electrochemical cells and batteries, and is applicable to testing mechanical, electrical, and chemical devices. Data obtained aids long-term performance prediction of battery or cell
Bilateral Diaphyseal Chondrodysplasia and Polymorphic Osteodysplasia of the Tibiofibulas in a Southern Leopard Frog, Lithobates sphenocephalus (Amphibia: Anura: Ranidae)
Much attention has been focused on limb malformations in anurans following the startling discovery of major limb deformities in Northern Leopard Frogs (Rana pipiens) in Minnesota in 1995. The numerous causes for these malformations can be attributed to a number of natural phenomena, or they can be considered as being manmade. In the present study, we report on a previously undescribed type of limb abnormality in a single individual of the Southern Leopard Frog (Lithobates sphenocephalus) from Arkansas. Histological examination of left tibiofibula revealed a complete disruption of the normal diaphyseal bone structure in this adult frog. The tibiofibula was separated into two poorly ossified and mostly fragmented bony shaft regions on opposite sides of the bone lesion. These peripheral segments of compact bone were surrounded by hypertrophic regions of hyaline cartilage intermingled with complexes of dysplastic bone. We observed three major polymorphic bone aggregates. The overall design of these osteogenic regions can best be described as an arachnoid-like patchwork of numerous pockets, channels, spaces, and nodules separated by trabeculae containing a matrix embedded with subperiosteal bone cells. At present, we are unaware of any environmental conditions that could account for the osteochondrous dysplasia in our specimen. Moreover, the remarkable bilateral placement of the 2 lesions in our specimen suggests the possibly of a genetic factor leading to a pairing of hindlimb developmental anomalies during embryonic bone growth in our specimen
Investigating the Ecology of the Mound-Building Ant, \u3ci\u3eAcanthomyops Claviger\u3c/i\u3e (Hymenoptera: Formicidae), in Re-Created Prairie
Acanthomyops claviger (Roger) (Hymenoptera: Formicidae) forms conspicuous mounds within clumps of big bluestem, Andropogon gerardii, and prairie dropseed, Sporobolus heterolepsis, within a re-created tallgrass prairie in northeastern Illinois. This study explored the ecology of the nesting ant in the recreated prairie regarding the persistence of colonies, soil characteristics, the growth of grass clumps, and the species richness of the surrounding flora. Persistence of nests over one year was positively correlated to the diameters of mounds created by the colonies. Differences in soil moisture at 10 cm depth were significant over a growing season between grass clumps having nests of A. claviger and those not. Soil temperature at 10 cm depth over a growing season, organic fraction of the soil, and above-ground oven-dried biomass of grasses did not significantly vary based on nest presence. Floral richness was significantly higher in the vicinity of A. claviger nests than where nests were absent. Benefits of the ant-grass relationship are unknown, although a commensalistic relationship is at least suggested by the location of nests in grass clumps. The presence of A. claviger nests appears to have a positive effect on the richness of the surrounding flora, possibly through soil tunneling and seed distribution
A study of the magnesium content of plant material
The experiments with grass and clover at Boghall and
ryegrass at Bush showed that: -1. the mineral content of different species of grass and
clover varied considerably, the clovers tending to be higher
in mineral content than the grasses.2. the mineral content of white clover was affected by the
grass with which it was grown and the competition with the
grass for the available nutrients, particularly in the case
of phosphorus.3. the mineral content of both grasses and clover varied
considerably from month to month, the nature of the variation
depending on the frequency of cutting. In grasses cut
monthly, the minerai content tended to increase towards the
end of the season, while in uncut ryegrass, the mineral
content decreased as the grass matured.4. treatment with "nitrochalk" increased the calcium and
magnesium contents of grasses throughout the season, and
increased the phosphorus content initially. The effect of
treatment on the clover seemed to depend on the yield and
leafiness of the grass with which it was grown and the
consequent competition between the grass and clover.5. treatment with heavy dressings of MgSO4.7H2O increased
he magnesium content of ryegrass throughout the season.
. the uptake of minerals varied from species to species
and from month to month throughout the season, the monthly
variation generally following that of the yield. The uptake
of minerals by clover was lower than that of the grasses
/because of the lower yield of the clover. The total seasonal
uptakes of calcium and of phosphorus were greater than the
uptake of magnesium.7. treatment with "nitrochalk" increased the uptake of all
three elements by both grass and clover.The mineral content of a sward will therefore depend on
the botanical composition of the sward, the frequency of
cutting, the time of year and tiffe fertiliser treatment.
The experiments with mixed herbage grown for hay and for
dried grass bore out these results and showed that: -1. the magnesium content of the herbage depended on the
available magnesium in the soil.2. the mineral content of herbage decreased with advancing
maturity.3. the effect of the fertilisers studied depended not only
on the nature of the fertiliser but also on the mineral status
of the soil to which it was applied and the existing cation:
anion ratios.(a) magnesium sulphate raised the magnesium content of
the herbage, particularly where the soil was low in available
magnesium.(b) potassium sulphate depressed the magnesium and
phsophorus contents of herbage and in some cases the calcium
content also.(c) potassium -magnesium sulphate had little effect on
the magnesium ani phosphorus contents of herbage, and was
therefore more suitable for use where the soil was low in
available magnesium.The experiments with turnips and kale showed that: -
1. the yield of dry matter and the uptake of minerals in
the leaf was less than that of the roots in turnips and of
the stem in kale.
2. the mineral content of the leaf was higher than that of
the roots in turnips and of the stem in kale.
3. the magnesium content of turnip leaves depended on the
available magnesium in the soil.
4. treatment with potassium -magnesium sulphate increased
¡the dry matter yield of turnip roots where the available
soil magnesium was low, and increased the yield of magnesium
content of kale leaves, and the uptake of magnesium by the
leaves
Deep level transient spectroscopy study for the development of ion-implanted silicon field-effect transistors for spin-dependent transport
A deep level transient spectroscopy (DLTS) study of defects created by
low-fluence, low-energy ion implantation for development of ion-implanted
silicon field-effect transistors for spin-dependent transport experiments is
presented. Standard annealing strategies are considered to activate the
implanted dopants and repair the implantation damage in test
metal-oxide-semiconductor (MOS) capacitors. Fixed oxide charge, interface
trapped charge and the role of minority carriers in DLTS are investigated. A
furnace anneal at 950 C was found to activate the dopants but did not
repair the implantation damage as efficiently as a 1000 C rapid
thermal anneal. No evidence of bulk traps was observed after either of these
anneals. The ion- implanted spin-dependent transport device is shown to have
expected characteristics using the processing strategy determined in this
study.Comment: 4 pages, 6 figure
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