179 research outputs found
Invariance Properties of Inviscid Fluids of Grade n
Revisited and completed version, 18 pages and 2 figures.International audienceFluids of grade n are continuous media in dynamic changes of phases avoiding the surfaces of discontinuity and representing the capillary layers in liquid-vapour interfaces. We recall the thermodynamic form of the equation of motion for inviscid fluids of grade n. First integrals and theorems of circulation are deduced. A general classification of flows is proposed
A model for the formation and evolution of traffic jams
In this paper, we establish and analyze a traffic flow model which describes the formation and dynamics of traffic jams. It consists of a pressureless gas dynamics system under a maximal constraint on the density and is derived through a singular limit of the Aw-Rascle model. From this analysis, we deduce the particular dynamical behavior of clusters (or traffic jams), defined as intervals where the density limit is reached. An existence result for a generic class of initial data is proved
by means of an approximation of the solution by a sequence of clusters. Finally, numerical simulations are produced
Durability and generalization of attribution-based feedback following failure: Effects on expectations and behavioral persistence
Objective: This experiment investigated, following perceived failure, the immediate, long-term (i.e., durability), and cross-situational (i.e., generalization) effects of attribution-based feedback on expectations and behavioral persistence. Design: We used a 3×2 (Group×Time) experimental design over seven weeks with attributions, expectations of success, and persistence as dependent measures. Method: 49 novice participants were randomly assigned to one of three treatment (attributional feedback) groups: (a) functional (i.e., controllable and unstable); (b) dysfunctional (i.e., uncontrollable and stable); or (c) no feedback. Testing involved three sessions, in which participants completed a total of five trials across two performance tasks (golf-putting and dart-throwing). In order to track whether the attributional manipulation conducted within the context of the golf-putting task in Session 2 would generalize to a new situation, participants performed a dart-throwing task in Session 3, and their scores were compared with those recorded at baseline (in Session 1). Results: Analysis of pre- and post-intervention measures of attributions, expectations, and persistence revealed that the functional attributional feedback led to more personally controllable attributions following failure in a golf-putting task, together with increases in success expectations and persistence. In contrast, dysfunctional attributional feedback led to more personally uncontrollable and stable attributions following failure, together with lower success expectations and reduced persistence. These effects extended beyond the intervention period, were present up to four weeks post intervention, and were maintained even when participants performed a different (i.e., dart-throwing) task. Conclusions: The findings demonstrate that attributional feedback effects are durable over time and generalize across situations
Classification of Possible Finite-Time Singularities by Functional Renormalization
Starting from a representation of the early time evolution of a dynamical
system in terms of the polynomial expression of some observable f (t) as a
function of the time variable in some interval 0 < t < T, we investigate how to
extrapolate/forecast in some optimal stability sense the future evolution of
f(t) for time t>T. Using the functional renormalization of Yukalov and Gluzman,
we offer a general classification of the possible regimes that can be defined
based on the sole knowledge of the coefficients of a second-order polynomial
representation of the dynamics. In particular, we investigate the conditions
for the occurence of finite-time singularities from the structure of the time
series, and quantify the critical time and the functional nature of the
singularity when present. We also describe the regimes when a smooth extremum
replaces the singularity and determine its position and amplitude. This extends
previous works by (1) quantifying the stability of the functional
renormalization method more accurately, (2) introducing new global constraints
in terms of moments and (3) going beyond the ``mean-field'' approximation.Comment: Latex document of 18 pages + 7 ps figure
Functional classification of protein toxins as a basis for bioinformatic screening
Proteins are fundamental to life and exhibit a wide diversity of activities, some of which are toxic. Therefore, assessing whether a specific protein is safe for consumption in foods and feeds is critical. Simple BLAST searches may reveal homology to a known toxin, when in fact the protein may pose no real danger. Another challenge to answer this question is the lack of curated databases with a representative set of experimentally validated toxins. Here we have systematically analyzed over 10,000 manually curated toxin sequences using sequence clustering, network analysis, and protein domain classification. We also developed a functional sequence signature method to distinguish toxic from non-toxic proteins. The current database, combined with motif analysis, can be used by researchers and regulators in a hazard screening capacity to assess the potential of a protein to be toxic at early stages of development. Identifying key signatures of toxicity can also aid in redesigning proteins, so as to maintain their desirable functions while reducing the risk of potential health hazards
Being one of us: Translating expertise into performance benefits following perceived failure
Is feedback delivered by an expert sufficient to improve performance? In two studies, we
tested, following failure, the influence of group membership (ingroup/outgroup) and source
expertise (high/low) on the effectiveness of attributional feedback on performance. Results
revealed a significant interactive effect, showing an increase of performance only when the
source was an expert ingroup member (Study 1). This interaction was replicated on
performance and success expectations in Study 2, which were significantly higher for high
compared to low expertise ingroup sources. These data suggest that sharing a common
identity with those you lead may help convert expert performance advice into real
performance benefits
Genome analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea
Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38–39 Mb genomes include 11,860–14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared t
Mental health (GHQ12; CES-D) and attitudes towards the value of work among inmates of a semi-open prison and the long-term unemployed in Luxembourg
Aim: To analyse the relationships between mental health and employment commitment among
prisoners and the long-term unemployed (LTU) trying to return to work.
Method: Fifty-two of 62 male inmates of a semi-open prison (Givenich Penitentiary Centre, the
only such unit in Luxembourg), and 69 LTU registered at the Luxembourg Employment
Administration completed a questionnaire exploring: 1) mental health (measured by means of
scales GHQ12 and CES-D); 2) employment commitment; 3) availability of a support network, selfesteem,
empowerment; and 4) socio-demographic characteristics.
Results: Compared with LTU, inmates were younger, more had work experience (54.9% vs
26.1%), and more were educated to only a low level (71.1% vs 58.0%). The link between
employment commitment and mental health in the LTU was the opposite of that seen among the
prisoners: the more significant the perceived importance of employment, the worse the mental
health (GHQ12 p = 0.003; CES-D p < 0.001) of the LTU; in contrast, among prisoners, the GHQ12
showed that the greater the perceived value of work, the lower the psychic distress (p = 0.012).
Greater empowerment was associated with less depression in both populations. The education
levels of people who did not reach the end of secondary school, whether inmates or LTU, were
negatively linked with their mental equilibrium.
Conclusion: The two groups clearly need professional support. Future research should further
investigate the link between different forms of professional help and mental health. Randomized
controlled trials could be carried out in both groups, with interventions to improve work
commitment for prisoners and to help with getting a job for LTU. For those LTU who value
employment but cannot find it, the best help may be psychological support
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