2,383 research outputs found
Stable self similar blow up dynamics for slightly L^2 supercritical NLS equations
We consider the focusing nonlinear Schr\"odinger equations in dimension and for slightly
supercritical nonlinearities p_c
with and 0<\e\ll 1. We prove the existence and stability in the energy space of a self similar finite time blow up dynamics and provide a qualitative description of the singularity formation near the blow up tim
The Elements of the Neutrino Mass Matrix: Allowed Ranges and Implications of Texture Zeros
We study the range of the elements of the neutrino mass matrix m_nu in the
charged lepton basis. Neutrino-less double beta decay is sensitive to the ee
element of m_nu. We then analyze the phenomenological implications of single
texture zeros. In particular, interesting predictions for the effective mass
can be obtained, in the sense that typically only little cancellation due to
the Majorana phases is expected. Some cases imply constraints on the
atmospheric neutrino mixing angle.Comment: 21 pages, 7 figures. Minor corrections, matches version in PR
An interior point algorithm for minimum sum-of-squares clustering
Copyright @ 2000 SIAM PublicationsAn exact algorithm is proposed for minimum sum-of-squares nonhierarchical clustering, i.e., for partitioning a given set of points from a Euclidean m-space into a given number of clusters in order to minimize the sum of squared distances from all points to the centroid of the cluster to which they belong. This problem is expressed as a constrained hyperbolic program in 0-1 variables. The resolution method combines an interior point algorithm, i.e., a weighted analytic center column generation method, with branch-and-bound. The auxiliary problem of determining the entering column (i.e., the oracle) is an unconstrained hyperbolic program in 0-1 variables with a quadratic numerator and linear denominator. It is solved through a sequence of unconstrained quadratic programs in 0-1 variables. To accelerate resolution, variable neighborhood search heuristics are used both to get a good initial solution and to solve quickly the auxiliary problem as long as global optimality is not reached. Estimated bounds for the dual variables are deduced from the heuristic solution and used in the resolution process as a trust region. Proved minimum sum-of-squares partitions are determined for the rst time for several fairly large data sets from the literature, including Fisher's 150 iris.This research was supported by the Fonds
National de la Recherche Scientifique Suisse, NSERC-Canada, and FCAR-Quebec
I TOO HAVE A VOICE: THE LITERACY EXPERIENCES OF BLACK BOYS ENGAGING WITH AND RESPONDING TO AFRICAN AMERICAN LITERATURE DEPICTING BLACK MALES
This study examined how the use of African American literature that depicts Black males influences the reading comprehension and the reading motivation of Black boys as demonstrated through oral, written, and creative expressions. Studies have been conducted using children’s literature with Black boys to examine their social interaction with the literature. However, there is limited research with Black boys interacting with African American literature depicting African American males. This research built upon and extended previous studies to determine the impact of the use of African American literature depicting Black males as an instructional strategy to influence the reading comprehension and motivation of Black boys. This study considered the use of creative responses to this literature, such as drama, writing, and visual arts.
A qualitative case study design was employed. A purposeful sample of third, fourth, and fifth grade Black boys were recruited to participate in this study. The research took place in a northeastern city at a local community center from July 2011 to August 2011. Data were collected using several instruments. These instruments included a reading motivation survey, a reading inventory, semi-structured interview questions, interactive read-aloud book discussions, with oral and written responses from the boys. Triangulation of methods was utilized (survey, interviews, book discussions, and boys’ written and illustrated artifacts). Field notes were kept, and interviews were transcribed. All data were analyzed, and coded to identify patterns and themes that emerged from the data. Those themes were: The boys experienced new texts, had new reading aspirations and learned about their culture; the boys demonstrated comprehension of text through active engagement, discussions, drawings, and written responses; the boys experienced racial inequalities through literature; the boys were exposed to new mentors; the boys were empowered and could envision their futures through their summer reading; and, the boys demonstrated spiritual awareness. The result from the study indicate that using African American literature depicting Black males is a valuable tool that can lead to increased comprehension and motivation
Improved Limit on theta_{13} and Implications for Neutrino Masses in Neutrino-less Double Beta Decay and Cosmology
We analyze the impact of a measurement, or of an improved bound, on
theta_{13} for the determination of the effective neutrino mass in
neutrino-less double beta decay and cosmology. In particular, we discuss how an
improved limit on (or a specific value of) theta_{13} can influence the
determination of the neutrino mass spectrum via neutrino-less double beta
decay. We also discuss the interplay with improved cosmological neutrino mass
searches.Comment: 22 pages, 5 figures. Minor corrections, matches version in PR
Environment Energy Assessment of Trips (EEAT): An updated approach to assess the environmental impacts of urban mobility, The case of Lille Region
This paper deals with sustainable mobility in an urban context. We investigate the assessment of the impacts of the evolution of travel behaviour (travelled distance and modal choice) in terms of energy consumption and greenhouse gases (GHG) emissions at the local level. Indeed, today, the control of exhausts generated by the mobility within the urban areas is at the core of the environmental policies and the stabilisation of GHG emissions is one of the main goals of 'sustainable development'. To face this challenge in the transport sector, the national government and local authorities need a better understanding of the link between urban development choices, the operation of the different modes of transport systems, and residents and non residents' attitude, and mobility patterns at the local level.MOBILITE ; ZONE URBAINE ; POLLUTION ATMOSPHERIQUE ; ENERGIE ; CONSOMMATION DE CARBURANT
Potassium: a new actor on the globular cluster chemical evolution stage. The case of NGC 2808
We derive [K/Fe] abundance ratios for 119 stars in the globular cluster NGC
2808, all of them having O, Na, Mg and Al abundances homogeneously measured in
previous works. We detect an intrinsic star-to-star spread in the Potassium
abundance. Moreover [K/Fe] abundance ratios display statistically significant
correlations with [Na/Fe] and [Al/Fe], and anti-correlations with [O/Fe] and
[Mg/Fe]. All the four Mg deficient stars ([Mg/Fe]<0.0) discovered so far in NGC
2808 are enriched in K by ~0.3 dex with respect to those with normal [Mg/Fe].
NGC 2808 is the second globular cluster, after NGC 2419, where a clear Mg-K
anti-correlation is detected, albeit of weaker amplitude. The simultaneous
correlation/anti-correlation of [K/Fe] with all the light elements usually
involved in the chemical anomalies observed in globular cluster stars, strongly
support the idea that these abundance patterns are due to the same
self-enrichment mechanism that produces Na-O and Mg-Al anti-correlations. This
finding suggests that detectable spreads in K abundances may be typical in the
massive globular clusters where the self-enrichment processes are observed to
produce their most extreme manifestations.Comment: Accepted for publication by ApJ, 5 pages, 3 figure
Tomography of the red supergiant star {\mu} Cep
A tomographic method, aiming at probing velocity fields at depth in stellar
atmospheres, is applied to the red supergiant star {\mu} Cep and to snapshots
of 3D radiative-hydrodynamics simulation in order to constrain atmospheric
motions and relate them to photometric variability.Comment: 2 pages, 2 figures, accepted as Proceedings of IAU Symposium No. 343,
201
Barriers To B2C Segment Of E-Business
The purpose of this paper is to identify several barriers affecting B2C segment growth and to project technological advances that may soften or eliminate these barriers. Included in the paper is an analysis of the interrelationship between barriers and products. Finally, the paper presents the impact of technology-controlled and human-controlled factors on Internet sale.  
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