8,444 research outputs found
Report on the EU-US Workshop on Large Scientific Databases
This joint workshop was set up under the auspices of the Joint European Commission/National Science Foundation Strategy Group that met in Budapest in September 1998. The meeting derived from a joint collaboration agreement between the EC and NSF, signed by Dr. George Metakides (Director of Information Technologies for the EC) and Prof. Juris Hartmanis (Director of Computer and Information Science and Engineering at the NSF). Some themes that were identified include:
digital libraries
human-centered computing and virtual environments
large scientific databases, and
intelligent implants
This report expresses the conclusions and recommendations of the Workshop on Large Scientific Databases, held in Annapolis, Maryland, USA in September 1999. The purpose of the workshop was to develop a report to the funding agencies outlining a possible solicitation to the research community, with emphasis on joint European-US work on Large Scientific Databases. Before the workshop, each participant submitted a position paper (these are available at the web site http://www.cacr.caltech.edu/euus). The results of the position papers, presentations, and group discussion are summarized in this report. There were 12 participants from Europe and 12 from the United States, and they are listed at the end of this report. The last section of this report describes possible funding mechanisms
Computing Matveev's complexity via crystallization theory: the boundary case
The notion of Gem-Matveev complexity has been introduced within
crystallization theory, as a combinatorial method to estimate Matveev's
complexity of closed 3-manifolds; it yielded upper bounds for interesting
classes of such manifolds. In this paper we extend the definition to the case
of non-empty boundary and prove that for each compact irreducible and
boundary-irreducible 3-manifold it coincides with the modified Heegaard
complexity introduced by Cattabriga, Mulazzani and Vesnin. Moreover, via
Gem-Matveev complexity, we obtain an estimation of Matveev's complexity for all
Seifert 3-manifolds with base and two exceptional fibers and,
therefore, for all torus knot complements.Comment: 27 pages, 14 figure
Global analysis of muon decay measurements
We have performed a global analysis of muon decay measurements to establish
model-independent limits on the space-time structure of the muon decay matrix
element. We find limits on the scalar, vector and tensor coupling of right- and
left-handed muons to right- and left-handed electrons. The limits on those
terms that involve the decay of right-handed muons to left-handed electrons are
more restrictive than in previous global analyses, while the limits on the
other non-standard model interactions are comparable. The value of the Michel
parameter eta found in the global analysis is -0.0036 \pm 0.0069, slightly more
precise than the value found in a more restrictive analysis of a recent
measurement. This has implications for the Fermi coupling constant G_F.Comment: 5 pages, 3 table
Efecto del agregado de alúmina en la calidad del material de aleación de Zinc NÃquel. Adsorción de la alúmina en las partÃculas que ermiten una mayor transferencia de materia al cátodo
En las aleaciones de Zn-Ni es importante un alto contenido de Ni porque aumenta la resistencia del material contra la corrosión. En este sentido, se encontró que la adición de concentraciones mayores de partÃculas de alúmina a la solución de electrólisis, hace que las mismas se incorporen al recubrimiento y aumente la composición de Ni y la microdureza. La adsorción se estudió por VoltametrÃa mediante electrodo gotero de mercurio para explicar por la adsorción, porque mayores concentraciones de partÃculas aumentan la concentración de NÃquel en la aleación. Se estudiaron las texturas en muestras preparadas a espesores crecientes, y su relación con la resistencia a la corrosión. El principal aporte de éste trabajo es que el material del recubrimiento con alúmina, modifica las texturas con espesores crecientes. El espesor óptimo en el que aumenta la textura disminuye la corriente de corrosión, a la vez que a 8Adm-2 el contenido de Ni es de 15 % y la dureza es alta para ZnNi de 350 Vickers, que está ligada al desgaste.Fil:Mahmud, Z. Instituto Nacional de TecnologÃa Industrial (INTI). Procesos SuperficialesFil:Pina, J. Instituto Nacional de TecnologÃa Industrial (INTI). Procesos SuperficialesFil:Gagliardi, J. Instituto Nacional de TecnologÃa Industrial (INTI). Procesos SuperficialesFil:MÃngolo, N. Comisión Nacional de EnergÃa Atómica (CNEA)Fil:Túlio, P. Universidade Tecnológica Federal do Paraná (UTFPR)Fil:Gordillo, G. Universidad de Buenos Aires (UBA). Facultad de Ciencias Exactas y Naturales. Departamento de QuÃmica Inorgánica, AnalÃtica y QuÃmica FÃsic
Compact 3-manifolds via 4-colored graphs
We introduce a representation of compact 3-manifolds without spherical
boundary components via (regular) 4-colored graphs, which turns out to be very
convenient for computer aided study and tabulation. Our construction is a
direct generalization of the one given in the eighties by S. Lins for closed
3-manifolds, which is in turn dual to the earlier construction introduced by
Pezzana's school in Modena. In this context we establish some results
concerning fundamental groups, connected sums, moves between graphs
representing the same manifold, Heegaard genus and complexity, as well as an
enumeration and classification of compact 3-manifolds representable by graphs
with few vertices ( in the non-orientable case and in the
orientable one).Comment: 25 pages, 11 figures; changes suggested by referee: references added,
figure 2 modified, results about classification of the manifolds in
Proposition 17 announced at the end of section 9. Accepted for publication in
RACSAM. The final publication is available at Springer (see DOI
Defining the role of dexmedetomidine in the prevention of delirium in the intensive care unit (ICU)
Dexmedetomidine is a highly selective α2 agonist used as a sedative agent. It also provides anxiolysis and sympatholysis without significant respiratory compromise or delirium. We conducted a systematic review to examine whether sedation of patients in the intensive care unit (ICU) with dexmedetomidine was associated with a lower incidence of delirium as compared to other nondexmedetomidine sedation strategies. A search of PUBMED, EMBASE, and the Cochrane Database of Systematic Reviews yielded only three trials from 1966 through April 2015 that met our predefined inclusion criteria and assessed dexmedetomidine and outcomes of delirium as their primary endpoint. The studies varied in regard to population, comparator sedation regimen, delirium outcome measure, and dexmedetomidine dosing. All trials are limited by design issues that limit our ability definitively to conclude that dexmedetomidine prevents delirium. Evidence does suggest that dexmedetomidine may allow for avoidance of deep sedation and use of benzodiazepines, factors both observed to increase the risk for developing delirium. Our assessment of currently published literature highlights the need for ongoing research to better delineate the role of dexmedetomidine for delirium prevention
Clinical effectiveness of baclofen for the treatment of alcohol dependence: A review
Baclofen, an agonist at the B subunit of gaba-aminobutyric acid receptor, possesses pharmacologic properties that may confer utility for the treatment of alcohol dependence. Research suggests that not only can it be useful in promoting maintenance of alcohol abstinence but also it may play a key role in decreasing alcohol cravings and anxiety often associated with alcohol dependence. To assess the benefit of baclofen for alcohol dependence, a review of the literature was conducted to identify published data investigating this off-label treatment. Four randomized controlled trials to date have been published and were included in this review. Although primary outcomes differ between studies, patients randomized to baclofen experience higher rates of abstinence from alcohol than those taking placebo in two of the trials. Secondary analyses indicate that baclofen is safe in patients with alcohol dependence, including those with moderate to severe liver cirrhosis, and may provide beneficial anxiolytic effects. Despite some positive data, the largest available randomized controlled trial failed to find any differences between baclofen and placebo. In all studies, individuals with severe medical comorbidities, seizure disorders, and psychiatric disorders were excluded from trials, which may limit external validity. In summary, there may be beneficial effects from using baclofen for the treatment of alcohol dependence; however, limited conclusions can be drawn from the small number of studies currently available for review. Larger well-designed trials are needed to further define baclofen’s role for the treatment of alcohol dependence
Photon-number-resolution with sub-30-ps timing using multi-element superconducting nanowire single photon detectors
A photon-number-resolving detector based on a four-element superconducting
nanowire single photon detector is demonstrated to have sub-30-ps resolution in
measuring the arrival time of individual photons. This detector can be used to
characterize the photon statistics of non-pulsed light sources and to mitigate
dead-time effects in high-speed photon counting applications. Furthermore, a
25% system detection efficiency at 1550 nm was demonstrated, making the
detector useful for both low-flux source characterization and high-speed
photon-counting and quantum communication applications. The design, fabrication
and testing of this detector are described, and a comparison between the
measured and theoretical performance is presented.Comment: 13 pages, 5 figure
Infrared absorption from Charge Density Waves in magnetic manganites
The infrared absorption of charge density waves coupled to a magnetic
background is first observed in two manganites La{1-x}Ca{x}MnO{3} with x = 0.5
and x = 0.67. In both cases a BCS-like gap 2 Delta (T), which for x=0.5 follows
the hysteretic ferro-antiferromagnetic transition, fully opens at a finite T{0}
< T{Neel}, with 2 Delta(T{0})/kT{c} close to 5. These results may also explain
the unusual coexistence of charge ordering and ferromagnetism in
La{0.5}Ca{0.5}MnO{3}.Comment: File revtex + 3 figs. in epsf. To appear on Phys. Rev. Let
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