4,301 research outputs found
Performance, emissions, and physical characteristics of a rotating combustion aircraft engine
The RC2-75, a liquid cooled two chamber rotary combustion engine (Wankel type), designed for aircraft use, was tested and representative baseline (212 KW, 285 BHP) performance and emissions characteristics established. The testing included running fuel/air mixture control curves and varied ignition timing to permit selection of desirable and practical settings for running wide open throttle curves, propeller load curves, variable manifold pressure curves covering cruise conditions, and EPA cycle operating points. Performance and emissions data were recorded for all of the points run. In addition to the test data, information required to characterize the engine and evaluate its performance in aircraft use is provided over a range from one half to twice its present power. The exhaust emissions results are compared to the 1980 EPA requirements. Standard day take-off brake specific fuel consumption is 356 g/KW-HR (.585 lb/BHP-HR) for the configuration tested
Correspondence between HBT radii and the emission zone in non-central heavy ion collisions
In non-central collisions between ultra-relativistic heavy ions, the
freeze-out distribution is anisotropic, and its major longitudinal axis may be
tilted away from the beam direction. The shape and orientation of this
distribution are particularly interesting, as they provide a snapshot of the
evolving source and reflect the space-time aspect of anisotropic flow.
Experimentally, this information is extracted by measuring pion HBT radii as a
function of angle with respect to the reaction plane. Existing formulae
relating the oscillations of the radii and the freezeout anisotropy are in
principle only valid for Gaussian sources with no collective flow. With a
realistic transport model of the collision, which generates flow and
non-Gaussian sources, we find that these formulae approximately reflect the
anisotropy of the freezeout distribution.Comment: 9 pages, 8 figure
Integrated care and the working record
By default, many discussions and specifications of electronic health records or integrated care records often conceptualize the record as a passive information repository. This article presents data from a case study of work in a medical unit in a major metropolitan hospital. It shows how the clinicians tailored, re-presented and augmented clinical information to support their own roles in the delivery of care for individual patients. This is referred to as the working record: a set of complexly interrelated clinician-centred documents that are locally evolved, maintained and used to support delivery of care in conjunction with the more patient-centred chart that will be stored in the medical records department on the patient’s discharge. Implications are drawn for how an integrated care record could support the local tailorability and flexibility that underpin this working record and hence underpin practice
Searching edges in the overlap of two plane graphs
Consider a pair of plane straight-line graphs, whose edges are colored red
and blue, respectively, and let n be the total complexity of both graphs. We
present a O(n log n)-time O(n)-space technique to preprocess such pair of
graphs, that enables efficient searches among the red-blue intersections along
edges of one of the graphs. Our technique has a number of applications to
geometric problems. This includes: (1) a solution to the batched red-blue
search problem [Dehne et al. 2006] in O(n log n) queries to the oracle; (2) an
algorithm to compute the maximum vertical distance between a pair of 3D
polyhedral terrains one of which is convex in O(n log n) time, where n is the
total complexity of both terrains; (3) an algorithm to construct the Hausdorff
Voronoi diagram of a family of point clusters in the plane in O((n+m) log^3 n)
time and O(n+m) space, where n is the total number of points in all clusters
and m is the number of crossings between all clusters; (4) an algorithm to
construct the farthest-color Voronoi diagram of the corners of n axis-aligned
rectangles in O(n log^2 n) time; (5) an algorithm to solve the stabbing circle
problem for n parallel line segments in the plane in optimal O(n log n) time.
All these results are new or improve on the best known algorithms.Comment: 22 pages, 6 figure
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Instrument calibration and measurement plan for the poorly measured/unmeasured category of highly enriched uranium at Lawrence Livermore National Laboratory
In partial response to a Department of Energy (DOE) request to evaluate the state of measurements of special nuclear material, Lawrence Livermore National Laboratory (LLNL) evaluated and classified all highly enriched uranium (HEU) metal and oxide items in its inventory. Because of a lack of traceable HEU standards, no items were deemed to fit the category of well measured. A subsequent DOE-HQ sponsored survey by New Brunswick Laboratory resulted in their preparation of a set of certified reference material (CRM) standards for HEU oxide (U{sub 3}O{sub 8}) that are projected for delivery during September of 1999. However, CRM standards for HEU metal are neither in preparation nor are they expected to be prepared within the foreseeable future. Consequently, HEU metal working standards must be developed if the poorly measured/unmeasured portion of the LLNL inventory is to be reclassified. This paper describes the approach that LLNL will take to (1) develop a set of HEU metal working standards; (2) develop HEU metal and oxide calibration curves for the passive-active neutron (PAN) shuffler that are functions of mass, enrichment, size, and shape; and (3) reclassify the poorly measured/unmeasured inventory through direct measurement or reprocessing of previously archived data
Children, family and the state : revisiting public and private realms
The state is often viewed as part of the impersonal public sphere in opposition to the private family as a locus of warmth and intimacy. In recent years this modernist dichotomy has been challenged by theoretical and institutional trends which have altered the relationship between state and family. This paper explores changes to both elements of the dichotomy that challenge this relationship: a more fragmented family structure and more individualised and networked support for children. It will also examine two new elements that further disrupt any clear mapping between state/family and public/private dichotomies: the third party role of the child in family/state affairs and children's application of virtual technology that locates the private within new cultural and social spaces. The paper concludes by examining the rise of the 'individual child' hitherto hidden within the family/state dichotomy and the implications this has for intergenerational relations at personal and institutional levels
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Assessing the pedestrian experience in public spaces
The assessment of the pedestrian experience in public spaces is increasingly becoming an essential constituent of urban street design. This paper first presents a new methodology for evaluating pedestrian environments through on-street surveys, building upon well-established comprehensive pedestrian audit tools, such as PERS and PEDS. The methodology is applied on the South Kensington area of London, in light of recent redevelopments seeing the conversion of the previous car-oriented layout to a more pedestrian-friendly one. The results suggest that the new design is generally perceived positively by pedestrians, but point out that there may be room for improvement in terms of pedestrian comfort. The results are then further analysed statistically in order to draw generic conclusions and investigate the effects of different aspects of the pedestrian environment on each other with respect to the pedestrian experience. By fitting a series of ordered logistic regression models, a number of interdependences are identified and interpreted
Combined Docking and Quantum Chemical Study on CYP-mediated Metabolism of Estrogens in Man
Long-term exposure
to estrogens seriously increases the incidence
of various diseases including breast cancer. Experimental studies
indicate that cytochrome P450 (CYP) enzymes catalyze the bioactivation
of estrogens to catechols, which can exert their harmful effects via
various routes. It has been shown that the 4-hydroxylation pathway
of estrogens is the most malign, while 2-hydroxylation is considered
a benign pathway. It is also known experimentally that with increasing
unsaturation of ring B of estrogens the prevalence of the 4-hydroxylation
pathway significantly increases. In this study, we used a combination
of structural analysis, docking, and quantum chemical calculations
at the B3LYP/6-311+G* level to investigate the factors that influence
the regioselectivity of estrogen metabolism in man. We studied the
structure of human estrogen metabolizing enzymes (CYP1A1, CYP1A2,
CYP1B1, and CYP3A4) in complex with estrone using docking and investigated
the susceptibility of estrone, equilin, and equilenin (which only
differ in the unsaturation of ring B) to undergo 2- and 4-hydroxylation
using several models of CYP enzymes (Compound I, methoxy, and phenoxy
radical). We found that even the simplest models could account for
the experimental difference between the 2- and 4- hydroxylation pathways
and thus might be used for fast screening purposes. We also show that
reactivity indices, specifically in this case the radical and nucleophilic
condensed Fukui functions, also correctly predict the likeliness of
estrogen derivatives to undergo 2- or 4-hydroxylation
Selected Toll-like Receptor Ligands and Viruses Promote Helper-Independent Cytotoxic T Cell Priming by Upregulating CD40L on Dendritic Cells
SummaryCD40L (CD154) on CD4+ T cells has been shown to license dendritic cells (DCs) via CD40 to prime cytotoxic T lymphocyte (CTL) responses. We found that the converse (CD40L on DCs) was also important. Anti-CD40L treatment decreased endogenous CTL responses to both ovalbumin and influenza infection even in the absence of CD4+ T cells. DCs expressed CD40L upon stimulation with agonists to Toll-like receptor 3 (TLR3) and TLR9. Moreover, influenza infection, which stimulates CTLs without help, upregulated CD40L on DCs, but herpes simplex infection, which elicits CTLs through help, did not. CD40L-deficient (Cd40lg−/−) DCs are suboptimal both in vivo in bone marrow chimera experiments and in vitro in mixed lymphocyte reactions. In contrast, Cd40lg−/− CD8+ T cells killed as effectively as wild-type cells. Thus, CD40L upregulation on DCs promoted optimal priming of CD8+ T cells without CD4+ T cells, providing a mechanism by which pathogens may elicit helper-independent CTL immunity
Characterisation of the Mouse Vasoactive Intestinal Peptide Receptor Type 2 Gene, Vipr2, and Identification of a Polymorphic LINE-1-like Sequence That Confers Altered Promoter Activity
The VPAC(2) receptor is a seven transmembrane spanning G protein-coupled receptor for two neuropeptides, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP). It has a distinct tissue-specific, developmental and inducible expression that underlies an important neuroendocrine role. Here, we report the characterisation of the gene that encodes the mouse VPAC(2) receptor (Vipr2), localisation of the transcriptional start site and functional analysis of the promoter region. The Vipr2 gene contains 12 introns within its protein-coding region and spans 68.6 kb. Comparison of the 5′ untranslated region sequences for cloned 5′-RACE products amplified from different tissues showed they all were contained within the same exon, with the longest extending 111 bp upstream of the ATG start site. Functional analysis of the 3.2-kb 5′-flanking region using sequentially deleted sequences cloned into a luciferase gene reporter vector revealed that this region is active as a promoter in mouse AtT20 D16:16 and rat GH4C1 cell lines. The core promoter is located within a 180-bp GC-rich region proximal to the ATG start codon and contains potential binding sites for Sp1 and AP2, but no TATA-box. Further upstream, in two out of three mice strains examined, we have discovered a 496-bp polymorphic DNA sequence that bears a significant identity to mouse LINE-1 DNA. Comparison of the promoter activity between luciferase reporter gene constructs derived from the BALB/c (which contains this sequence) and C57BL/6J (which lacks this sequence) Vipr2 promoter regions has shown three-fold difference in luciferase gene activity when expressed in mouse AtT20 D16:16 and αT3-1 cells, but not when expressed in the rat GH4C1 cells or in COS 7 cells. Our results suggest that the mouse Vipr2 gene may be differentially active in different mouse strains, depending on the presence of this LINE-1-like sequence in the promoter region
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