246 research outputs found
Small Engine Component Technology (SECT) study. Program report
The study was conducted to identify high payoff technologies for year 2000 small gas turbine applications and to provide a technology plan for guiding future research and technology efforts. A regenerative cycle turboprop engine was selected for a 19 passenger commuter aircraft application. A series of engines incorporating eight levels of advanced technologies were studied and their impact on aircraft performance was evaluated. The study indicated a potential reduction in fuel burn of 38.3 percent. At 2.00 per gallon, the potential DOC benefit would increase to 17.0 percent. Four advanced technologies are recommended and appropriate research and technology programs were established to reach the year 2000 goals
Studying the impact of ocean eddies on the ecosystem of the Prince Edward Islands: DEIMEC ll
The Dynamics of Eddy Impacts on Marion’s Ecosystem Study (DEIMEC) programme was begun in 2002 with the aim of understanding the importance of the oceanic, upstream environment to the ecosystem of the Prince Edward Islands. This island group consists of two small volcanic islands and provides many opportunities for studying ecological and evolutionary processes, for monitoring ecological changes in relation to global climate change and for conserving a unique component of the planet’s biological diversity
Clinicopathological findings in cats tested for feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV)
This retrospective study aimed to evaluate the clinicopathological changes in a population of cats tested for feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV), in an Italian Veterinary University Hospital, in the period between January 2002 and May 2016. During the period of 14 years, 1834 cats were tested, and of these 241/1834 (13.1%) were positive for FIV antibodies and 92/1834 (5%) cats were positive for FeLV antigen. These data confirm the presence of a high prevalence of these viruses on Italian territory. To the authors’ knowledge, this study describes findings that have never been evaluated before, such as iron status in retrovirus-infected cats and urinalysis in FeLV-positive cats. In this study, FIV-positive cats were more likely to have higher serum protein concentration and lower albumin-globulin ratio than other groups of cats. Lower urine specific gravity and higher urine protein to creatinine ratio were also detected for FIV-positive cats when compared with negative and healthy cats. FeLV-positive cats were more likely to have cytopenia, decreased haemoglobin, haematocrit and RBC compared with other groups of cats. The data obtained underline the importance of considering retroviral infections in the presence of a broad spectrum of risk factors and laboratory anomalies
Structure and distribution of the slope fish community in the vicinity of the sub-Antarctic Prince Edward Archipelago
Demersal fish community structure, distribution and trophic relationships on the slope (depth range 200–1500 m) of the sub-Antarctic Prince Edward Islands and surrounding sea rises were investigated during a pilot survey conducted in April 2001 onboard fishing vessel MV Iris. A total of 56 fish taxa were collected during the survey, of which 44 were identified to the species level, seven to the genus level and five to the family level. Among the identified taxa, 36 constituted new records for the area investigated. Total catch per unit effort (cpue) during the survey ranged from 1•1 to 241•2 individuals h 1. Both average fish diversity and total cpue positively correlated with trawling depth. Overall, mean sampling depth and near-bottom temperature explained 56% of total fish cpue. Hierarchal cluster analysis identified three distinct fish assemblages with pronounced dominant species. Major shifts in fish community composition occurred at 500–600 m and 800–900 m depth strata and could probably be a result of physical and biological vertical zonation. Analysis of the diet of selected fish species showed that they were generalist feeders, consuming predominantly pelagic, including epipelagic, meso- and benthopelagic, prey. Diets of six species and nitrogen stable isotope signatures of 22 species revealed that with a few exceptions most fishes occupied the fourth trophic level and were tertiary consumers. Wide variability in carbon isotopic signatures is discussed with respect to alternative, e.g. possible importance of high Antarctic and chemoautotrophic v. photoautotrophic sub-Antarctic primary production, organic matter sources at the base of deep-sea food webs
Physical and biological coupling in eddies in the lee of the South-West Indian Ridge
Eddies have some decisive functions in the dynamics of the Southern Ocean ecosystems. This is particularly true in the Indian sector of the Southern Ocean, where a region of unusually high-mesoscale variability has been observed in the vicinity of the South-West Indian Ridge. In April 2003, three eddies were studied: eddy A, a recently spawned anticyclone south of the Antarctic Polar Front (APF),; eddy B, an anticyclone north of lying between the Subantarctic Front and the APF; and eddy C, a cyclone north of the APF west of the ridge. Elevated concentrations of total Chl-a coincided with the edges of the cyclonic eddy, whereas both anticyclonic eddies A and B were characterised by low total Chl-a concentrations. Biologically, the two anticyclonic eddies A and B were distinctly different in their biogeographic origin. The zooplankton community in the larger anticyclonic eddy A was similar in composition to the Antarctic Polar Frontal Zone (APFZ) community with an addition of some Antarctic species suggesting an origin just north of the APF. In contrast, the species composition within the second anticyclonic eddy B appeared to be more typical of the transitional nature of the APFZ, comprising species of both subantarctic and subtropical origin and thus influenced by intrusions of water masses from both north and south of the Subantarctic Front. Back-tracking of these features shows that the biological composition clearly demarcates the hydrographic origin of these features
Small eigenvalues of the staggered Dirac operator in the adjoint representation and Random Matrix Theory
The low-lying spectrum of the Dirac operator is predicted to be universal,
within three classes, depending on symmetry properties specified according to
random matrix theory. The three universal classes are the orthogonal, unitary
and symplectic ensemble. Lattice gauge theory with staggered fermions has
verified two of the cases so far, unitary and symplectic, with staggered
fermions in the fundamental representation of SU(3) and SU(2). We verify the
missing case here, namely orthogonal, with staggered fermions in the adjoint
representation of SU(N_c), N_c=2, 3.Comment: 3 pages, revtex, 2 postscript figure
Studying the impact of ocean eddies on the ecosystem of the Prince Edward Islands: DEIMEC ll
The Dynamics of Eddy Impacts on Marion’s Ecosystem Study (DEIMEC) programme was begun in 2002 with the aim of understanding the importance of the oceanic, upstream environment to the ecosystem of the Prince Edward Islands. This island group consists of two small volcanic islands and provides many opportunities for studying ecological and evolutionary processes, for monitoring ecological changes in relation to global climate change and for conserving a unique component of the planet’s biological diversity
Temozolomide plus pegylated interferon alfa-2b as first-line treatment for stage IV melanoma: a multicenter phase II trial of the Dermatologic Cooperative Oncology Group (DeCOG)
Background: Combination of temozolomide (TMZ) with nonpegylated interferon alfa is associated with increased efficacy in terms of response rates compared with monotherapy. A multicenter phase II study was carried out to assess the activity and toxicity of TMZ plus pegylated interferon alfa-2b (peg-IFNα-2b), hypothesizing improved efficacy due to modified pharmacokinetic properties of the novel interferon (IFN) formulation. Patients and methods: In all, 124 patients with stage IV melanoma without prior chemotherapy and no cerebral metastases were treated with 100 μg peg-IFNα-2b s.c. per week and oral TMZ 200 mg/m2 (days 1-5, every 28 days). Primary study end point was objective response, and secondary end points were overall and progression-free survival (PFS) and safety. Results: In all, 116 patients were assessable for response: 2 (1.7%) had a complete response and 19 (16.4%) a partial response (overall response rate 18.1%). Of total, 25.0% achieved disease stabilization and 56.9% progressed. Overall survival was 9.4 months; PFS was 2.8 months. Grade 3/4 thrombocytopenia occurred in 20.7% and grade 3/4 leukopenia in 23.3%. Conclusions: The efficacy of TMZ plus peg-IFNα-2b in this large phase II study is moderate and comparable to published results of the combination of TMZ with non-peg-IFN. Likewise, the safety profile of peg-IFNα-2b seems to be similar to non-peg-IFN when combined with TM
Reduced risk of myocardial infarct and revascularization following coronary artery bypass grafting compared with percutaneous coronary intervention in patients with chronic kidney disease
Coronary atherosclerotic disease is highly prevalent in chronic kidney disease (CKD). Although revascularization improves outcomes, procedural risks are increased in CKD and unbiased data comparing bypass surgery (CABG) and percutaneous intervention (PCI) in CKD are sparse. To compare outcomes of CABG and PCI in stage 3-5 CKD, we identified randomized trials comparing these procedures. Investigators were contacted to obtain individual, patient-level data. Ten of 27 trials meeting inclusion criteria provided data. These trials enrolled 3993 patients encompassing 526 patients with stage 3-5 CKD of which 137 were stage 3b-5 CKD. Among individuals with stage 3-5 CKD survival through 5-years was not different following CABG compared with PCI (hazard ratio 0.99, 95% confidence interval: 0.67, 1.46) or stage 3b-5 CKD (1.29: 0.68, 2.46). However, CKD modified the impact on survival free from myocardial infarction: it was not different between CABG and PCI for individuals with preserved kidney function (0.97: 0.80, 1.17), but was significantly lower following CABG in stage 3-5 CKD (0.49: 0.29, 0.82) and stage 3b-5 CKD (0.23: 0.09, 0.58). Repeat revascularization was reduced following CABG compared with PCI regardless of baseline kidney function. Results were limited by unavailability of data from several trials and paucity of enrolled patients with stage 4-5 CKD. Thus, our patient-level meta-analysis of individuals with CKD randomized to CABG versus PCI suggests that CABG significantly reduces the risk of subsequent myocardial infarction and revascularization without impacting survival in these patients
Domain wall fermion zero modes on classical topological backgrounds
The domain wall approach to lattice fermions employs an additional dimension,
in which gauge fields are merely replicated, to separate the chiral components
of a Dirac fermion. It is known that in the limit of infinite separation in
this new dimension, domain wall fermions have exact zero modes, even for gauge
fields which are not smooth. We explore the effects of finite extent in the
fifth dimension on the zero modes for both smooth and non-smooth topological
configurations and find that a fifth dimension of around ten sites is
sufficient to clearly show zero mode effects. This small value for the extent
of the fifth dimension indicates the practical utility of this technique for
numerical simulations of QCD.Comment: Updated fig. 3-7, small changes in sect. 3, added fig. 8, added more
reference
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