5,278 research outputs found
Evolution of the Dependence of Residual Lifetimes
We investigate the dependence properties of a vector of residual lifetimes by means of the copula associated with the conditional distribution function. In particular, the evolution of positive dependence properties (like quadrant dependence and total positivity) are analyzed and expressions for the evolution of measures of association are given
An extremal problem for the Bergman kernel of orthogonal polynomials
Let be a curve of class . For
in the unbounded component of , and for
, let be a probability measure with supp which minimizes the Bergman function
at among all
probability measures on (here,
are an orthonormal basis in for
the holomorphic polynomials of degree at most ). We show that
tends weak-* to , the balayage of the point
mass at onto , by relating this to an optimization problem for
probability measures on the unit circle. Our proof makes use of estimates for
Faber polynomials associated to .Comment: To appear in Constructive Approximatio
Simulation Application for the LHCb Experiment
We describe the LHCb detector simulation application (Gauss) based on the
Geant4 toolkit. The application is built using the Gaudi software framework,
which is used for all event-processing applications in the LHCb experiment. The
existence of an underlying framework allows several common basic services such
as persistency, interactivity, as well as detector geometry description or
particle data to be shared between simulation, reconstruction and analysis
applications. The main benefits of such common services are coherence between
different event-processing stages as well as reduced development effort. The
interfacing to Geant4 toolkit is realized through a facade (GiGa) which
minimizes the coupling to the simulation engine and provides a set of abstract
interfaces for configuration and event-by-event communication. The Gauss
application is composed of three main blocks, i.e. event generation, detector
response simulation and digitization which reflect the different stages
performed during the simulation job. We describe the overall design as well as
the details of Gauss application with a special emphasis on the configuration
and control of the underlying simulation engine. We also briefly mention the
validation strategy and the planing for the LHCb experiment simulation.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 9 eps figures. PSN
TUMT00
Influence of Topological Edge States on the Properties of Al/Bi2Se3/Al Hybrid Josephson Devices
In superconductor-topological insulator-superconductor hybrid junctions, the
barrier edge states are expected to be protected against backscattering, to
generate unconventional proximity effects, and, possibly, to signal the
presence of Majorana fermions. The standards of proximity modes for these types
of structures have to be settled for a neat identification of possible new
entities. Through a systematic and complete set of measurements of the
Josephson properties we find evidence of ballistic transport in coplanar
Al-Bi2Se3-Al junctions that we attribute to a coherent transport through the
topological edge state. The shunting effect of the bulk only influences the
normal transport. This behavior, which can be considered to some extent
universal, is fairly independent of the specific features of superconducting
electrodes. A comparative study of Shubnikov - de Haas oscillations and
Scanning Tunneling Spectroscopy gave an experimental signature compatible with
a two dimensional electron transport channel with a Dirac dispersion relation.
A reduction of the size of the Bi2Se3 flakes to the nanoscale is an unavoidable
step to drive Josephson junctions in the proper regime to detect possible
distinctive features of Majorana fermions.Comment: 11 pages, 14 figure
Mathematical Modeling for Studying the Sustainability of Plants Subject to the Stress of Two Distinct Herbivores
Viability of plants, especially endangered species, are usually affected by multiple stressors, including insects, herbivores, environmental factors and other plant species. We present new mathematical models, based on systems of ordinary differential equations, of two distinct herbivore species feeding (two stressors) on the same plant species. The new feature is the explicit functional form modeling the simultaneous feedback interactions (synergistic or additive or antagonistic) between the three species in the ecosystem. The goal is to investigate whether the coexistence of the plant and both herbivore species is possible (a sustainable system) and under which conditions sustainability is feasible. Our theoretical analysis of the novel model without including competitions among the two herbivores reveals that the number of equilibrium states and their local stability depends on the type of interaction between the stressors: synergistic or additive or antagonistic. Our numerical results, based on value of parameters available, suggest that a sustainable system requires significant herbivore inter- or intra-species competition or both types. Additionally, our numerical findings indicate that competition and interaction of additive type promotes coexistence equilibrium states with the highest plant biomass. Furthermore, the system can exhibit periodic behavior and show the potential for multi-stability
Report of one case of probable feline ehrlichiosis
Les auteurs ont observĂ© chez un chat une anĂ©mie importante accom pagnĂ©e d 'hyperthermie et dâextrĂȘme fatigue, avec la prĂ©sence dans le cytoplasme des mononuclĂ©aires d'inclusions ayant lâaspect de Morula dâehrlichia.The authors observed in one cat : anemia, fever, anorexia, weight loss, a Morula of erhlichia canis in the cytoplasma of feline monocytes
C-terminal phosphorylation of NaV1.5 impairs FGF13-dependent regulation of channel inactivation
International audienceVoltage-gated Na(+) (NaV) channels are key regulators of myocardial excitability, and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII)-dependent alterations in NaV1.5 channel inactivation are emerging as a critical determinant of arrhythmias in heart failure. However, the global native phosphorylation pattern of NaV1.5 subunits associated with these arrhythmogenic disorders and the associated channel regulatory defects remain unknown. Here, we undertook phosphoproteomic analyses to identify and quantify in situ the phosphorylation sites in the NaV1.5 proteins purified from adult WT and failing CaMKIIÎŽc-overexpressing (CaMKIIÎŽc-Tg) mouse ventricles. Of 19 native NaV1.5 phosphorylation sites identified, two C-terminal phosphoserines at positions 1938 and 1989 showed increased phosphorylation in the CaMKIIÎŽc-Tg compared with the WT ventricles. We then tested the hypothesis that phosphorylation at these two sites impairs fibroblast growth factor 13 (FGF13)-dependent regulation of NaV1.5 channel inactivation. Whole-cell voltage-clamp analyses in HEK293 cells demonstrated that FGF13 increases NaV1.5 channel availability and decreases late Na(+) current, two effects that were abrogated with NaV1.5 mutants mimicking phosphorylation at both sites. Additional co-immunoprecipitation experiments revealed that FGF13 potentiates the binding of calmodulin to NaV1.5 and that phosphomimetic mutations at both sites decrease the interaction of FGF13 and, consequently, of calmodulin with NaV1.5. Together, we have identified two novel native phosphorylation sites in the C terminus of NaV1.5 that impair FGF13-dependent regulation of channel inactivation and may contribute to CaMKIIÎŽc-dependent arrhythmogenic disorders in failing hearts
Parental Mentalizing during Middle Childhood: How Is the Adoption of a Reflective Stance Associated with Childâs Psychological Outcomes?
This exploratory cross-sectional study attempts to understand the mechanisms underlying the role of parental mentalizing in a childâs psychological functioning during middle childhood by using Parental Reflective Functioning (PRF) and Parental Insightfulness (PI) constructs. The main aims are to examine the role of PI and PRF as processes capable of influencing a childâs psychological functioning in terms of emotionalâbehavioral difficulties and socialâemotional competencies. Eighty-six community parents (48 mothers, 38 fathers) and their 50 children in middle childhood (Mage = 10.10, SD = 1.13) participated in this study, recruited through a non-probabilistic sampling. The following measures were used to assess the aims of this study: Insightfulness Assessment, Parental Reflective Functioning Questionnaire, Child Behavior Check-list (CBCL) and Devereux Student Strengths Assessment (DESSA) questionnaires. Results showed that parental mentalizing was found to be significantly associated with both childâs internalizing and externalizing symptoms and socialâemotional competencies as reported by parents through the CBCL and DESSA questionnaires. This study may offer a contribution to the study of parental mentalizing during middle childhood, supporting the hypothesis that both parentsâ ability to understand their childâs mental states could affect the childâs psychological functioning. Clinical and theoretical implications are geared toward a family-based view with a specific focus on the importance of fostering in both parents a positive attitude toward mentalizing processes
Reducing the impact of radioactivity on quantum circuits in a deep-underground facility
As quantum coherence times of superconducting circuits have increased from
nanoseconds to hundreds of microseconds, they are currently one of the leading
platforms for quantum information processing. However, coherence needs to
further improve by orders of magnitude to reduce the prohibitive hardware
overhead of current error correction schemes. Reaching this goal hinges on
reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we
show that environmental radioactivity is a significant source of nonequilibrium
quasiparticles. Moreover, ionizing radiation introduces time-correlated
quasiparticle bursts in resonators on the same chip, further complicating
quantum error correction. Operating in a deep-underground lead-shielded
cryostat decreases the quasiparticle burst rate by a factor fifty and reduces
dissipation up to a factor four, showcasing the importance of radiation
abatement in future solid-state quantum hardware
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