1,182 research outputs found
Clinical surveillance of thrombotic microangiopathies in Scotland, 2003-2005
The prevalence, incidence and outcomes of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) are not well established in adults or children from prospective studies. We sought to identify both outcomes and current management strategies using prospective, national surveillance of HUS and TTP, from 2003 to 2005 inclusive. We also investigated the links between these disorders and factors implicated in the aetiology of HUS and TTP including infections, chemotherapy, and immunosuppression. Most cases of HUS were caused by verocytotoxin-producing Escherichia coli (VTEC), of which serotype O157 predominated, although other serotypes were identified. The list of predisposing factors for TTP was more varied although use of immunosuppressive agents and severe sepsis, were the most frequent precipitants. The study demonstrates that while differentiating between HUS and TTP is sometimes difficult, in most cases the two syndromes have quite different predisposing factors and clinical parameters, enabling clinical and epidemiological profiling for these disorders
Quantum Logic with a Single Trapped Electron
We propose the use of a trapped electron to implement quantum logic
operations. The fundamental controlled-NOT gate is shown to be feasible. The
two quantum bits are stored in the internal and external (motional) degrees of
freedom.Comment: 7 Pages, REVTeX, No Figures, To appear in Phys. Rev.
Shell-model description of monopole shift in neutron-rich Cu
Variations in the nuclear mean-field, in neutron-rich nuclei, are
investigated within the framework of the nuclear shell model. The change is
identified to originate mainly from the monopole part of the effective two-body
proton-neutron interaction. Applications for the low-lying states in odd- Cu
nuclei are presented. We compare the results using both schematic and realistic
forces. We also compare the monopole shifts with the results obtained from
large-scale shell-model calculations, using the same realistic interaction, in
order to study two-body correlations beyond the proton mean-field variations.Comment: Phys. Rev. C (in press
Social and physical environmental correlates of adults\u27 weekend sitting time and moderating effects of retirement status and physical health
Emerging research suggests that prolonged sedentary behaviour (SB) is detrimental to health. Changes in SB patterns are likely to occur during particular life stages, for example at retirement age (55-65-year-old). Evidence on socio-ecological SB correlates is scarce and inconsistent in this age group. Moreover, the influence of socio-ecological correlates may vary depending on health and retirement status. This study examined social and environment correlates of overall weekend day sitting among adults at or approaching retirement age, and moderating effects of perceived physical health and retirement status. Baseline data from the Wellbeing, Eating and Exercise for a Long Life study in 2839 Australian adults (55-65-year-old) were analysed. Participants self-reported proximal social factors, neighbourhood social and physical environment, physical health and retirement status. MLwiN multilevel regression analyses were conducted. In the multivariable model, only social support from friends/colleagues to discourage sitting (B = -0.891; p = 0.036) was associated with overall weekend day sitting. No moderation of retirement status, nor physical health were found in the multivariable results. Results from this study suggest the importance of social factors in relation to weekend day sitting among 55-65-year-old adults. Health promotion initiatives in this age group should pay special attention to enhancing social interaction opportunities. Moreover, findings suggest that SB-specific correlates may need to be examined in future research
CPT and Lorentz Tests in Penning Traps
A theoretical analysis is performed of Penning-trap experiments testing CPT
and Lorentz symmetry through measurements of anomalous magnetic moments and
charge-to-mass ratios. Possible CPT and Lorentz violations arising from
spontaneous symmetry breaking at a fundamental level are treated in the context
of a general extension of the SU(3) x SU(2) x U(1) standard model and its
restriction to quantum electrodynamics. We describe signals that might appear
in principle, introduce suitable figures of merit, and estimate CPT and Lorentz
bounds attainable in present and future Penning-trap experiments. Experiments
measuring anomaly frequencies are found to provide the sharpest tests of CPT
symmetry. Bounds are attainable of approximately in the
electron-positron case and of for a suggested experiment with
protons and antiprotons. Searches for diurnal frequency variations in these
experiments could also limit certain types of Lorentz violation to the level of
in the electron-positron system and others at the level of
in the proton-antiproton system. In contrast, measurements comparing
cyclotron frequencies are sensitive within the present theoretical framework to
different kinds of Lorentz violation that preserve CPT. Constraints could be
obtained on one figure of merit in the electron-positron system at the level of
, on another in the proton-antiproton system at , and on a
third at using comparisons of ions with antiprotons.Comment: 31 pages, published in Physical Review
Possible Spontaneous Breaking of Lorentz and CPT Symmetry
One possible ramification of unified theories of nature such as string theory
that may underlie the conventional standard model is the possible spontaneous
breakdown of Lorentz and CPT symmetry. In this talk, the formalism for
inclusion of such effects into a low-energy effective field theory is
presented. An extension of the standard model that includes Lorentz- and
CPT-breaking terms is developed. The restriction of the standard model
extension to the QED sector is then discussed.Comment: Talk presented at Non-Accelerator New Physics, Dubna, Russia, July
199
Neighbourhood, Route and Workplace-Related Environmental Characteristics Predict Adults' Mode of Travel to Work
Commuting provides opportunities for regular physical activity which can reduce the risk of chronic disease. Commuters' mode of travel may be shaped by their environment, but understanding of which specific environmental characteristics are most important and might form targets for intervention is limited. This study investigated associations between mode choice and a range of objectively assessed environmental characteristics.Participants in the Commuting and Health in Cambridge study reported where they lived and worked, their usual mode of travel to work and a variety of socio-demographic characteristics. Using geographic information system (GIS) software, 30 exposure variables were produced capturing characteristics of areas around participants' homes and workplaces and their shortest modelled routes to work. Associations between usual mode of travel to work and personal and environmental characteristics were investigated using multinomial logistic regression.Of the 1124 respondents, 50% reported cycling or walking as their usual mode of travel to work. In adjusted analyses, home-work distance was strongly associated with mode choice, particularly for walking. Lower odds of walking or cycling rather than driving were associated with a less frequent bus service (highest versus lowest tertile: walking OR 0.61 [95% CI 0.20–1.85]; cycling OR 0.43 [95% CI 0.23–0.83]), low street connectivity (OR 0.22, [0.07–0.67]; OR 0.48 [0.26–0.90]) and free car parking at work (OR 0.24 [0.10–0.59]; OR 0.55 [0.32–0.95]). Participants were less likely to cycle if they had access to fewer destinations (leisure facilities, shops and schools) close to work (OR 0.36 [0.21–0.62]) and a railway station further from home (OR 0.53 [0.30–0.93]). Covariates strongly predicted travel mode (pseudo r-squared 0.74).Potentially modifiable environmental characteristics, including workplace car parking, street connectivity and access to public transport, are associated with travel mode choice, and could be addressed as part of transport policy and infrastructural interventions to promote active commuting
Breaking CPT by mixed non-commutativity
The mixed component of the non-commutative parameter \theta_{\mu M}, where
\mu = 0,1,2,3 and M is an extra dimensional index may violate four-dimensional
CPT invariance. We calculate one and two-loop induced couplings of \theta_{\mu
5} with the four-dimensional axial vector current and with the CPT odd dim=6
operators starting from five-dimensional Yukawa and U(1) theories. The
resulting bounds from clock comparison experiments place a stringent constraint
on \theta_{\mu 5}, |\theta_{\mu 5}|^{-1/2} > 5\times 10^{11} GeV. The orbifold
projection and/or localization of fermions on a 3-brane lead to CPT-conserving
physics, in which case the constraints on \theta{\mu 5} are softened.Comment: 4 pages, latex, 1 figur
Relación de la firmeza de flor del cuero con el módulo de elasticidad de sus capas flor y corium
En los trabajos previos (l a 13) hemos estudiado el comportamiento de algunas emulsiones acrílicas impregnadas comerciales y señalado causas que pueden provocar variaciones en determinadas propiedades del cuero. Nos hemos también permitido efectuar ciertas disquisiciones con respecto al mecanismo involucrado en la firmeza de la flor del cuero (break) en base a resultados propios y sobre las teorías que sustentan otros autores respecto a la mejora del break por aplicación de impregnantes poliméricos.
El objetivo de este trabajo es obtener nuevos conocimientos sobre el proceso de impregnación analizando la influencia que tiene el tipo de polímero empleado sobre el aumento del break del cuero y su relación con otras propiedades del mismo.
En este caso no podemos emplear emulsiones comerciales puesto que ello requeriría disponer de una gama variada de polímeros impregnantes de diferentes propiedades fisicoquímicas manteniendo constantes otras características del polímero y de la emulsión en sí misma. Por ello, sintetizamos en el C1TEC los impregnantes acrílicos a utilizar en el estudio.Trabajo presentado al XV Congreso de la Unión Internacional de Sociedades de Químicos y Tecnólogos del Cuero, Hamburgo, setiembre 1977
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