2,971 research outputs found
Next-to-next-to-leading-order epsilon expansion for a Fermi gas at infinite scattering length
We extend previous work on applying the epsilon-expansion to universal
properties of a cold, dilute Fermi gas in the unitary regime of infinite
scattering length. We compute the ratio xi = mu/epsilon_F of chemical potential
to ideal gas Fermi energy to next-to-next-to-leading order (NNLO) in
epsilon=4-d, where d is the number of spatial dimensions. We also explore the
nature of corrections from the order after NNLO.Comment: 28 pages, 14 figure
Obtaining Bounds on The Sum of Divergent Series in Physics
Under certain circumstances, some of which are made explicit here, one can
deduce bounds on the full sum of a perturbation series of a physical quantity
by using a variational Borel map on the partial series. The method is
illustrated by applying it to various examples, physical and mathematical.Comment: 33 pages, Journal Versio
New geometries for high spatial resolution hall probes
The Hall response function of symmetric and asymmetric planar Hall effect
devices is investigated by scanning a magnetized tip above a sensor surface
while simultaneously recording the topography and the Hall voltage. Hall sensor
geometries are tailored using a Focused Ion Beam, in standard symmetric and new
asymmetric geometries. With this technique we are able to reduce a single
voltage probe to a narrow constriction 20 times smaller than the other device
dimensions. We show that the response function is peaked above the
constriction, in agreement with numerical simulations. The results suggest a
new way to pattern Hall sensors for enhanced spatial resolution.Comment: 12 pages, 5 figures, submitted to Journal of Applied Physic
Developments in the South Staffordshire iron and steel industry, 1850-1913, in the light of home and foreign competition
When Ebenezer Parkes was discussing the question of foreign competition as it affected the local iron and steel industry at the turn of the century, he stressed that it was a 'many sided thing'. Besides, if South Staffordshire was to reassert itself, then improvements would have to come about in a number of areas - in education, use of labour-saving machinery, practices in the blast furnace and rolling-mill departments, labour relations, canal and rail transport, structure of industry, state support and Colonial trade. This thesis is an attempt to look at the various 'sides' of the South Staffordshire iron and steel industry as it faced up to increasing competition both from other United Kingdom districts and from abroad. The importance of physical factors is considered in conjunction with human ones. Clearly, South Staffordshire could do nothing to prevent the growth of new centres of iron and steel production; furthermore, other older centres of production, notably South Wales and Scotland, fared better in the second half of the nineteenth century because of their tidal locations. Iron ores from Spain or steel 'semis' from the United States or the European Continent tended to emphasise the shift away from a land-locked centre of production. Abroad, tremendous growth was experienced by the iron and steel industries of the United States and Germany, a development which made all the apparent disadvantages of South Staffordshire appear that much more significant. Of these disadvantages, South Staffordshire's almost total dependence on outside supplies of metallurgical coke ranks very high. So, too, do the numerous shortcomings of the transport facilities of the area. On the human side, the failure of the local ironmasters to take full advantage of the proximity of East Midland iron ore supplies was crucial. Their reliance upon outside supplies of iron are, which remained largely out of their control, put them in sharp contrast with producers on the Continent or in the United states. To add to the difficulties being experienced by the local industry, Birmingham and the Black Country proved a very attractive market for foreign producers. The so-called 'dumping' policies of the Americans and Continentals are pursued at some length in the last chapter. Despite the many changes which took place in the district, South Staffordshire remained a very important part of the United Kingdom iron and steel industry. The fortunes of Round Oak, and especially those of Sir Alfred Hickman's Spring Vale Works, illustrate the fact that overall the situation in South Staffordshire was never a totally hopeless one
Infections Ă©mergentes Ă Acinetobacter baumannii et circonstances favorisant leur survenue
During the last decade, Acinetobacter baumannii (AB) has been increasingly responsible for infections occurring in three particular contexts (in terms of patients and environment). Community AB pneumonia is severe infections, mainly described around the Indian Ocean, and which mainly concern patients with major co-morbidities. AB is also responsible for infections occurring among soldiers wounded in action during operations conducted in Iraq or Afghanistan. Lastly, this bacterium is responsible for infections occurring among casualties from natural disasters like earthquakes and tsunamis. Those infections are often due to multidrug-resistant strains, which can be implicated in nosocomial outbreaks when patients are hospitalized in a local casualty department or during their repatriation thereafter. The source of the contaminations which lead to AB infections following injuries (warfare or natural disasters) is still poorly known. Three hypotheses are usually considered: a contamination of wounds with environmental bacteria, a wound contamination from a previous cutaneous or oropharyngeal endogenous reservoir, or hospital acquisition. The implication of telluric or agricultural primary reservoirs in human AB infections is a common hypothesis which remains to be demonstrated by further specifically designed studies
Methicillin-resistant Staphylococcus aureus (MRSA) in the institutionalized older patient
SummaryNursing homes and long-term care facilities are usually considered as reservoirs for methicillin-resistant Staphylococcus aureus (MRSA) carriers. Actually, there are major differences in MRSA carriage between institutions, with variations from 1% to more than 30%. Overall there is a low incidence of MRSA infection in these institutions, even though carriage is associated with a higher risk of subsequent MRSA infection, with high mortality rates. The main risk factors for carriage are well known: recent hospitalization in an acute-care ward, skin wounds and recent antimicrobial therapy. Age over 75 years is also a risk factor. Residents of nursing homes and long-term care facilities pose a risk of MRSA transfer to acute-care wards, with potential consequences in terms of infection control strategy or surgical antibiotic prophylaxis. No well-designed study has identified the best strategy for MRSA control in institutions for older people and strategies that have been proposed are controversial. Studies to elucidate this would be useful, as well as studies specifically designed to identify the relative importance of different ways of MRSA transmission in these institutions (cross-transmission via healthcare workers or the environment, or direct transmission from one resident to another). Finally, a first important step towards MRSA control is a strict application of standard precautions, particularly good compliance with hand hygiene
Loury – Le Bourg
Date de l'opération : 1990 - 1991 (SU) Inventeur(s) : Guillou M Après une première campagne de fouille organisée en 1983 sur un site gallo-romain découvert dans le bourg de Loury (Gallia, 1985 : 342), au nord de l’église et du château, une seconde campagne a permis de découvrir un muret dont seule la fondation subsiste (10,15 m de longueur, 0,60 m de largeur, 0,20 à 0,60 m de hauteur), qui appartient probablement à une construction gallo-romaine, et une fosse comblée avec des gravats provenan..
Critical Behavior of an Ising System on the Sierpinski Carpet: A Short-Time Dynamics Study
The short-time dynamic evolution of an Ising model embedded in an infinitely
ramified fractal structure with noninteger Hausdorff dimension was studied
using Monte Carlo simulations. Completely ordered and disordered spin
configurations were used as initial states for the dynamic simulations. In both
cases, the evolution of the physical observables follows a power-law behavior.
Based on this fact, the complete set of critical exponents characteristic of a
second-order phase transition was evaluated. Also, the dynamic exponent of the critical initial increase in magnetization, as well as the critical
temperature, were computed. The exponent exhibits a weak dependence
on the initial (small) magnetization. On the other hand, the dynamic exponent
shows a systematic decrease when the segmentation step is increased, i.e.,
when the system size becomes larger. Our results suggest that the effective
noninteger dimension for the second-order phase transition is noticeably
smaller than the Hausdorff dimension. Even when the behavior of the
magnetization (in the case of the ordered initial state) and the
autocorrelation (in the case of the disordered initial state) with time are
very well fitted by power laws, the precision of our simulations allows us to
detect the presence of a soft oscillation of the same type in both magnitudes
that we attribute to the topological details of the generating cell at any
scale.Comment: 10 figures, 4 tables and 14 page
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