1,718 research outputs found
de Branges-Rovnyak spaces: basics and theory
For a contractive analytic operator-valued function on the unit disk
, de Branges and Rovnyak associate a Hilbert space of analytic
functions and related extension space
consisting of pairs of analytic functions on the unit disk . This
survey describes three equivalent formulations (the original geometric de
Branges-Rovnyak definition, the Toeplitz operator characterization, and the
characterization as a reproducing kernel Hilbert space) of the de
Branges-Rovnyak space , as well as its role as the underlying
Hilbert space for the modeling of completely non-isometric Hilbert-space
contraction operators. Also examined is the extension of these ideas to handle
the modeling of the more general class of completely nonunitary contraction
operators, where the more general two-component de Branges-Rovnyak model space
and associated overlapping spaces play key roles. Connections
with other function theory problems and applications are also discussed. More
recent applications to a variety of subsequent applications are given in a
companion survey article
Pauvreté et accès à l'eau dans la vallée du Sénégal
Water poverty in the Senegal Valley Considering the flood-recession agriculture, the hydraulic history of the valley of the Senegal River is ancient, but knows a deep mutation since the introduction of the irrigation. Can one speak of water poverty, whereas two dams now control the water flow of the Senegal River and ensure a permanent abundance in water ? The answer to this questioning is proposed through the link between poverty, access to funding, access to land, and involvement in resource management.L'histoire hydraulique de la vallée du fleuve Sénégal est ancienne et remonte à la culture de décrue. Mais elle connaît une profonde mutation depuis l'introduction de l'irrigation. Peut-on parler de « pauvreté hydraulique », alors que deux barrages régulent à présent le régime du fleuve Sénégal et assurent une permanence de l'abondance en eau ? La réponse à cette question est proposée sous l'angle de l'articulation entre la pauvreté, l'accès au financement, l'accès au foncier, la participation à la gestion de la ressource
Pauvreté et accès à l'eau dans la vallée du Sénégal
L'histoire hydraulique de la vallée du fleuve Sénégal est ancienne et remonte à la culture de décrue. Mais elle connaît une profonde mutation depuis l'introduction de l'irrigation. Peut-on parler de « pauvreté hydraulique », alors que deux barrages régulent à présent le régime du fleuve Sénégal et assurent une permanence de l'abondance en eau ? La réponse à cette question est proposée sous l'angle de l'articulation entre la pauvreté, l'accès au financement, l'accès au foncier, la participation à la gestion de la ressource.HYDRAULIQUE ; HISTOIRE ; AMENAGEMENT HYDROAGRICOLE ; CULTURE DE DECRUE ; CULTURE IRRIGUEE ; SORGHO ; MIL ; RIZ IRRIGUE ; ACCES A LA TERRE ; RESSOURCES EN EAU ; GESTION DE L'ENVIRONNEMENT ; ACCES AU CREDIT ; TENURE FONCIERE ; ENDETTEMENT ; EXCLUSION SOCIALE ; PAUVRETE ; REVENUS AGRICOLES ; ORGANISATION PAYSANNE ; ACCES A L'EAU ; GESTION DE L'EAU ; SENEGAL ; FLEUVE SENEGAL VALLEE
Topic Study Group No. 42: Uses of Technology in Lower Secondary Mathematics Education (Age 10\u201314)
This is the report of the TSG 42 at ICME 13
A clinician’s guide to management of intra-abdominal hypertension and abdominal compartment syndrome in critically ill patients
This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901
Impact-parameter dependent nuclear parton distribution functions: EPS09s and EKS98s and their applications in nuclear hard processes
We determine the spatial (impact parameter) dependence of nuclear parton
distribution functions (nPDFs) using the -dependence of the spatially
independent (averaged) global fits EPS09 and EKS98. We work under the
assumption that the spatial dependence can be formulated as a power series of
the nuclear thickness functions . To reproduce the -dependence over the
entire range we need terms up to . As an outcome, we release two
sets, EPS09s (LO, NLO, error sets) and EKS98s, of spatially dependent nPDFs for
public use. We also discuss the implementation of these into the existing
calculations. With our results, the centrality dependence of nuclear
hard-process observables can be studied consistently with the globally fitted
nPDFs for the first time. As an application, we first calculate the LO nuclear
modification factor for primary partonic-jet production in
different centrality classes in Au+Au collisions at RHIC and Pb+Pb collisions
at LHC. Also the corresponding central-to-peripheral ratios are
studied. We also calculate the LO and NLO nuclear modification factors for
single inclusive neutral pion production, , at mid- and
forward rapidities in different centrality classes in d+Au collisions at RHIC.
In particular, we show that our results are compatible with the PHENIX
mid-rapidity data within the overall normalization uncertainties given by the
experiment. Finally, we show our predictions for the corresponding
modifications in the forthcoming p+Pb collisions at LHC.Comment: 36 page
Distortions of Subjective Time Perception Within and Across Senses
Background: The ability to estimate the passage of time is of fundamental importance for perceptual and cognitive processes. One experience of time is the perception of duration, which is not isomorphic to physical duration and can be distorted by a number of factors. Yet, the critical features generating these perceptual shifts in subjective duration are not understood.
Methodology/Findings: We used prospective duration judgments within and across sensory modalities to examine the effect of stimulus predictability and feature change on the perception of duration. First, we found robust distortions of perceived duration in auditory, visual and auditory-visual presentations despite the predictability of the feature changes in the stimuli. For example, a looming disc embedded in a series of steady discs led to time dilation, whereas a steady disc embedded in a series of looming discs led to time compression. Second, we addressed whether visual (auditory) inputs could alter the perception of duration of auditory (visual) inputs. When participants were presented with incongruent audio-visual stimuli, the perceived duration of auditory events could be shortened or lengthened by the presence of conflicting visual information; however, the perceived duration of visual events was seldom distorted by the presence of auditory information and was never perceived shorter than their actual durations.
Conclusions/Significance: These results support the existence of multisensory interactions in the perception of duration and, importantly, suggest that vision can modify auditory temporal perception in a pure timing task. Insofar as distortions in subjective duration can neither be accounted for by the unpredictability of an auditory, visual or auditory-visual event, we propose that it is the intrinsic features of the stimulus that critically affect subjective time distortions
Envelope Determinants of Equine Lentiviral Vaccine Protection
Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the challenge virus Env gp90 protein compared to the vaccine virus gp90. The report demonstrated approximately 100% protection of immunized ponies from disease after challenge by virus with a homologous gp90 (EV0), and roughly 40% protection against challenge by virus (EV13) with a gp90 13% divergent from the vaccine strain. In the current study we examine whether the protection observed when challenging with the EV0 strain could be conferred to animals via chimeric challenge viruses between the EV0 and EV13 strains, allowing for mapping of protection to specific Env sequences. Viruses containing the EV13 proviral backbone and selected domains of the EV0 gp90 were constructed and in vitro and in vivo infectivity examined. Vaccine efficacy studies indicated that homology between the vaccine strain gp90 and the N-terminus of the challenge strain gp90 was capable of inducing immunity that resulted in significantly lower levels of post-challenge virus and significantly delayed the onset of disease. However, a homologous N-terminal region alone inserted in the EV13 backbone could not impart the 100% protection observed with the EV0 strain. Data presented here denote the complicated and potentially contradictory relationship between in vitro virulence and in vivo pathogenicity. The study highlights the importance of structural conformation for immunogens and emphasizes the need for antibody binding, not neutralizing, assays that correlate with vaccine protection. © 2013 Craigo et al
Gender Differences in Publication Output: Towards an Unbiased Metric of Research Performance
We examined the publication records of a cohort of 168 life scientists in the field of ecology and evolutionary biology to assess gender differences in research performance. Clear discrepancies in publication rate between men and women appear very early in their careers and this has consequences for the subsequent citation of their work. We show that a recently proposed index designed to rank scientists fairly is in fact strongly biased against female researchers, and advocate a modified index to assess men and women on a more equitable basis
photoproduction on the proton for photon energies from 0.725 to 2.875 GeV
Differential cross sections for the reaction have been
measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged
photon beam with energies from 0.725 to 2.875 GeV. Where available, the results
obtained here compare well with previously published results for the reaction.
Agreement with the SAID and MAID analyses is found below 1 GeV. The present set
of cross sections has been incorporated into the SAID database, and exploratory
fits have been made up to 2.7 GeV. Resonance couplings have been extracted and
compared to previous determinations. With the addition of these cross sections
to the world data set, significant changes have occurred in the high-energy
behavior of the SAID cross-section predictions and amplitudes.Comment: 18 pages, 10 figure
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