1,195 research outputs found
Enhanced nitrogen diffusion induced by atomic attrition
The nitrogen diffusion in steel is enhanced by previous atomic attrition with low energy xenon ions. The noble gas bombardment generates nanoscale texture surfaces and stress in the material. The atomic attrition increases nitrogen diffusion at lower temperatures than the ones normally used in standard processes. The stress causes binding energy shifts of the Xe 3d(5/2) electron core level. The heavy ion bombardment control of the texture and stress of the material surfaces may be applied to several plasma processes where diffusing species are involved. (c) 2006 American Institute of Physics.882
Current and potential geographical distribution of Platymeris biguttatus (Linnaeus, 1767) with description of nymphs
Background: The description of Platymeris biguttatus (Linnaeus 1767) nymphal instars as well as the prediction of
the potentially suitable ecological niche was the main goal of this study. Our research was based on 258 specimens
of P. biguttatus species of museum collections. A set of 23 environmental predictor variables covering Africa was
used at ecological niche modeling - a method performed using the Maxent software to prepare potential distribution
maps for this species.
Results: The results suggested the most suitable areas seen as potentially suitable ecological niche for P. biguttatus in
Africa. A jackknife test showed that temperature seasonality and percentage of tree cover were among the most
important environmental variables affecting the distribution of the species. The analysis of climate preferences shows
that most of the potentially suitable niches for this species were located in the area of tropical savanna climate, with a
small participation of tree vegetation.
Conclusions: P. biguttatus was only known to be widely distributed in the tropical part of continental Africa. Thanks to
the ecological niche modeling methods and the museum data on the occurrence of the species, we introduced new
information about potentially suitable ecological niches and the possible range of distribution
Colistin and tobramycin resistance during long- term use of selective decontamination strategies in the intensive care unit: a post hoc analysis
Murine and Bovine γΎ T Cells Enhance Innate Immunity against Brucella abortus Infections
γΎ T cells have been postulated to act as a first line of defense against infectious agents, particularly intracellular pathogens, representing an important link between the innate and adaptive immune responses. Human γΎ T cells expand in the blood of brucellosis patients and are active against Brucella in vitro. However, the role of γΎ T cells in vivo during experimental brucellosis has not been studied. Here we report TCRÎŽâ/â mice are more susceptible to B. abortus infection than C57BL/6 mice at one week post-infection as measured by splenic colonization and splenomegaly. An increase in TCRγΎ cells was observed in the spleens of B. abortus-infected C57BL/6 mice, which peaked at two weeks post-infection and occurred concomitantly with diminished brucellae. γΎ T cells were the major source of IL-17 following infection and also produced IFN-Îł. Depletion of γΎ T cells from C57BL/6, IL-17Rαâ/â, and GMCSFâ/â mice enhanced susceptibility to B. abortus infection although this susceptibility was unaltered in the mutant mice; however, when γΎ T cells were depleted from IFN-Îłâ/â mice, enhanced susceptibility was observed. Neutralization of γΎ T cells in the absence of TNF-α did not further impair immunity. In the absence of TNF-α or γΎ T cells, B. abortus-infected mice showed enhanced IFN-Îł, suggesting that they augmented production to compensate for the loss of γΎ T cells and/or TNF-α. While the protective role of γΎ T cells was TNF-α-dependent, γΎ T cells were not the major source of TNF-α and activation of γΎ T cells following B. abortus infection was TNF-α-independent. Additionally, bovine TCRγΎ cells were found to respond rapidly to B. abortus infection upon co-culture with autologous macrophages and could impair the intramacrophage replication of B. abortus via IFN-Îł. Collectively, these results demonstrate γΎ T cells are important for early protection to B. abortus infections
How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRRâs Rehabilitation Engineering Research Centers
Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a âtotal approach to rehabilitationâ, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970âs, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program
A Measurement of Rb using a Double Tagging Method
The fraction of Z to bbbar events in hadronic Z decays has been measured by
the OPAL experiment using the data collected at LEP between 1992 and 1995. The
Z to bbbar decays were tagged using displaced secondary vertices, and high
momentum electrons and muons. Systematic uncertainties were reduced by
measuring the b-tagging efficiency using a double tagging technique. Efficiency
correlations between opposite hemispheres of an event are small, and are well
understood through comparisons between real and simulated data samples. A value
of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is
statistical and the second systematic. The uncertainty on Rc, the fraction of Z
to ccbar events in hadronic Z decays, is not included in the errors. The
dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the
deviation of Rc from the value 0.172 predicted by the Standard Model. The
result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the
Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European
Physical Journal
First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector
The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nu” and [overline nu ]” charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nu” and [overline nu ]” interactions are separated. The ratio of [overline nu ]” to nu” events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nu” and [overline nu ]”
Measurement of the B+ and B-0 lifetimes and search for CP(T) violation using reconstructed secondary vertices
The lifetimes of the B+ and B-0 mesons, and their ratio, have been measured in the OPAL experiment using 2.4 million hadronic Z(0) decays recorded at LEP. Z(0) --> b (b) over bar decays were tagged using displaced secondary vertices and high momentum electrons and muons. The lifetimes were then measured using well-reconstructed charged and neutral secondary vertices selected in this tagged data sample. The results aretau(B+) = 1.643 +/- 0.037 +/- 0.025 pstau(Bo) = 1.523 +/- 0.057 +/- 0.053 pstau(B+)/tau(Bo) = 1.079 +/- 0.064 +/- 0.041,where in each case the first error is statistical and the second systematic.A larger data sample of 3.1 million hadronic Z(o) decays has been used to search for CP and CPT violating effects by comparison of inclusive b and (b) over bar hadron decays, No evidence fur such effects is seen. The CP violation parameter Re(epsilon(B)) is measured to be Re(epsilon(B)) = 0.001 +/- 0.014 +/- 0.003and the fractional difference between b and (b) over bar hadron lifetimes is measured to(Delta tau/tau)(b) = tau(b hadron) - tau((b) over bar hadron)/tau(average) = -0.001 +/- 0.012 +/- 0.008
Traditional use of the Andean flicker (Colaptes rupicola) as a galactagogue in the Peruvian Andes
This paper explores the use of the dried meat and feathers of the Andean Flicker (Colaptes rupicola) to increase the milk supply of nursing women and domestic animals in the Andes. The treatment is of preColumbian origin, but continues to be used in some areas, including the village in the southern Peruvian highlands where I do ethnographic research. I explore the factors giving rise to and sustaining the practice, relate it to other galactagogues used in the Andes and to the use of birds in ethnomedical and ethnoveterinary treatments in general, and situate it within the general tendency in the Andes and elsewhere to replicate human relations in the treatment of valuable livestock. The bird's use as a galactagogue appears to be motivated by both metaphorical associations and its perceived efficacy, and conceptually blends human and animal healthcare domains
Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at âs = 7 TeV with the ATLAS detector
This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of âs = 7 TeV;{\rm Te}{\rm V}4.6\;{\rm f}{{{\rm b}}^{-1}}{{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}|\eta |\lt 1.9{{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques
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