1,444 research outputs found
A History of the Rambouillet Breed of Sheep in Utah
The domestic sheep in the flocks in the state of Utah all trace their origins back to Europe. Between the sixteenth century and the present, sheep have made at least six different journeys from the old world to America and have fused their blood in the formation of the sheep industry of Utah. Each of these movements has a dramatic and interesting story to be told, but the trek of the Rambouillet is perhaps the most fascinating of all. The journey began in Spain, when by sea and by land the hardy fine-wool Spanish Merino made its way into France in 1786 by order of Louis XVI who desired to make France independent of Spain for its supply of fine wool. Here in France a new breed was created and struggled for existence during the period of revolutionary upheaval, emerging as the French Merino or Rambouillet sheep. The trek continued into Germany in the mid 1800\u27s, where under the standard of Germany, more remarkable changes were wrought by the German breeders. Then, taking to the sea again, the wandering breed crossed the Atlantic Ocean to New York and the New England States. Here the Rambouillet was rejected by eastern breeders in the 1850\u27s and several of the flocks were moved en masse to California by steamer via the Isthumus of Panama as well as overland in trail herds. Wool growing was beginning to attract attention at the time, and California breeders welcomed the opportunity of effecting improvements in their herds by infusing the blood of the superior Rambouillet into the inferior remnants of the old mission flocks and stock trailed in from New Mexico. By 1880 the Rambouillet was moving in numbers onto the arid ranges of Utah. Here the surroundings and the continual migrations for pasture with the change of the seasons paralleled the age-old practice of Spain where the sheep are shuttled back and forth between the foothills of the Pyrenees and the plains of Estremadura. And here in Utah some of the Rambouillet\u27s greatest triumphs and contributions were made as purebred flocks were established and the Rambouillet blood was infused throughout the range herds of the state
A laser-driven target of high-density nuclear polarized hydrogen gas
We report the best figure-of-merit achieved for an internal nuclear polarized
hydrogen gas target and a Monte Carlo simulation of spin-exchange optical
pumping. The dimensions of the apparatus were optimized using the simulation
and the experimental results were in good agreement with the simulation. The
best result achieved for this target was 50.5% polarization with 58.2% degree
of dissociation of the sample beam exiting the storage cell at a hydrogen flow
rate of atoms/s.Comment: Accepted as a Rapid Communication article in Phys. Rev.
Namib Desert dune/interdune transects exhibit habitat-specific edaphic bacterial communities.
The sand dunes and inter-dune zones of the hyper-arid central Namib Desert represent heterogeneous soil habitats. As little is known about their indigenous edaphic bacterial communities, we aimed to evaluate their diversity and factors of assembly and hypothesized that soil physicochemistry gradients would strongly shape dune/interdune communities. We sampled a total of 125 samples from 5 parallel dune/interdune transects and characterized 21 physico-chemical edaphic parameters coupled with 16S rRNA gene bacterial community fingerprinting using T-RFLP and 454 pyrosequencing. Multivariate analyses of T-RFLP data showed significantly different bacterial communities, related to physico-chemical gradients, in four distinct dune habitats: the dune top, slope, base and interdune zones. Pyrosequencing of 16S rRNA gene amplicon sets showed that each dune zone presented a unique phylogenetic profile, suggesting a high degree of environmental selection. The combined results strongly infer that habitat filtering is an important factor shaping Namib Desert dune bacterial communities, with habitat stability, soil texture and mineral and nutrient contents being the main environmental drivers of bacterial community structures
Homotopy Theoretic Models of Type Theory
We introduce the notion of a logical model category which is a Quillen model
category satisfying some additional conditions. Those conditions provide enough
expressive power that one can soundly interpret dependent products and sums in
it. On the other hand, those conditions are easy to check and provide a wide
class of models some of which are listed in the paper.Comment: Corrected version of the published articl
Diel-scale temporal dynamics recorded for bacterial groups in Namib Desert soil
Microbes in hot desert soil partake in core ecosystem processes e.g., biogeochemical cycling of carbon. Nevertheless, there is still a fundamental lack of insights regarding short-term (i.e., over a 24-hour [diel] cycle) microbial responses to highly fluctuating microenvironmental parameters like temperature and humidity. To address this, we employed T-RFLP fingerprinting and 454 pyrosequencing of 16S rRNA-derived cDNA to characterize potentially active bacteria in Namib Desert soil over multiple diel cycles. Strikingly, we found that significant shifts in active bacterial groups could occur over a single 24-hour period. For instance, members of the predominant Actinobacteria phyla exhibited a significant reduction in relative activity from morning to night, whereas many Proteobacterial groups displayed an opposite trend. Contrary to our leading hypothesis, environmental parameters could only account for 10.5% of the recorded total variation. Potential biotic associations shown through co-occurrence networks indicated that non-random inter- and intra-phyla associations were 'time-of-day-dependent' which may constitute a key feature of this system. Notably, many cyanobacterial groups were positioned outside and/or between highly interconnected bacterial associations (modules); possibly acting as inter-module 'hubs' orchestrating interactions between important functional consortia. Overall, these results provide empirical evidence that bacterial communities in hot desert soils exhibit complex and diel-dependent inter-community associations.EM201
Orthogonal Block Structure and Uniformly Best Linear Unbiased Estimators
Models with orthogonal block structure, OBS, have variance covariance
matrices that are linear combinations [...]info:eu-repo/semantics/publishedVersio
The SASSCAL contribution to climate observation, climate data management and data rescue in Southern Africa
A major task of the newly established "Southern African Science Service Centre for Climate Change and Adaptive Land Management" (SASSCAL; www.sasscal.org) and its partners is to provide science-based environmental information and knowledge which includes the provision of consistent and reliable climate data for Southern Africa. Hence, SASSCAL, in close cooperation with the national weather authorities of Angola, Botswana, Germany and Zambia as well as partner institutions in Namibia and South Africa, supports the extension of the regional meteorological observation network and the improvement of the climate archives at national level. With the ongoing rehabilitation of existing weather stations and the new installation of fully automated weather stations (AWS), altogether 105 AWS currently provide a set of climate variables at 15, 30 and 60 min intervals respectively. These records are made available through the SASSCAL WeatherNet, an online platform providing near-real time data as well as various statistics and graphics, all in open access. This effort is complemented by the harmonization and improvement of climate data management concepts at the national weather authorities, capacity building activities and an extension of the data bases with historical climate data which are still available from different sources. These activities are performed through cooperation between regional and German institutions and will provide important information for climate service related activities
Recommended from our members
Hypertension in Women of Reproductive Age in the United States: NHANES 1999-2008
Objective: To examine the epidemiology of hypertension in women of reproductive age. Methods: Using NHANES from 1999–2008, we identified 5,521 women age 20–44 years old. Hypertension status was determined using blood pressure measurements and/or self-reported medication use. Results: The estimated prevalence of hypertension in women of reproductive age was 7.7% (95% confidence interval (CI): 6.9%–8.5%). The prevalence of anti-hypertensive pharmacologic therapy was 4.2% (95% CI 3.5%–4.9%). The prevalence of hypertension was relatively stable across the study period; the age and race adjusted odds of hypertension in 2007–2008 did not differ significantly from 1999–2000 (odds ratio 1.2, CI 0.8 to 1.7, p = 0.45). Significant independent risk factors associated with hypertension included older age, non-Hispanic black race (compared to non-Hispanic whites), diabetes mellitus, chronic kidney disease, and higher body mass index. The most commonly used antihypertensive medications included diuretics, angiotensin-converting enzyme inhibitors (ACE), and beta blockers. Conclusion: Hypertension occurs in about 8% of women of reproductive age. There are remarkable differences in the prevalence of hypertension between racial/ethnic groups. Obesity is a risk factor of particular importance in this population because it affects over 30% of young women in the U.S., is associated with more than 4 fold increased risk of hypertension, and is potentially modifiable
- …