522 research outputs found
Dynamics of semi-flexible polymer solutions in the highly entangled regime
We present experimental evidence that the effective medium approximation
(EMA), developed by D.C. Morse [Phys. Rev. E {\bf 63}, 031502, (2001)],
provides the correct scaling law of the macroscopic plateau modulus
(where is the contour length per
unit volume and is the persistence length) of semi-flexible polymer
solutions, in the highly entangled concentration regime. Competing theories,
including a self-consistent binary collision approximation (BCA), have instead
predicted . We have tested both the EMA and
BCA scaling predictions using actin filament (F-actin) solutions which permit
experimental control of independently of other parameters. A combination
of passive video particle tracking microrheology and dynamic light scattering
yields independent measurements of the elastic modulus and
respectively. Thus we can distinguish between the two proposed laws, in
contrast to previous experimental studies, which focus on the (less
discriminating) concentration functionality of .Comment: 4 pages, 6 figures, Phys. Rev. Lett. (accepted
Integrating ASCAT surface soil moisture and GEOV1 leaf area index into the SURFEX modelling platform: a land data assimilation application over France
The land monitoring service of the European Copernicus programme has
developed a set of satellite-based biogeophysical products, including
surface soil moisture (SSM) and leaf area index (LAI). This study
investigates the impact of joint assimilation of remotely sensed SSM
derived from Advanced Scatterometer (ASCAT) backscatter data and the
Copernicus Global Land GEOV1 satellite-based LAI product
into the the vegetation growth version of the Interactions
between Soil Biosphere Atmosphere (ISBA-A-gs) land surface model
within the the externalised surface model (SURFEX) modelling
platform of Météo-France. The ASCAT data were bias corrected with
respect to the model climatology by using a seasonal-based CDF
(Cumulative Distribution Function) matching technique. A multivariate
multi-scale land data assimilation system (LDAS) based on the extended
Kalman Filter (EKF) is used for monitoring the soil moisture,
terrestrial vegetation, surface carbon and energy fluxes across the
domain of France at a spatial resolution of 8 km. Each model grid
box is divided into a number of land covers, each having its own set of
prognostic variables. The filter algorithm is designed to provide
a distinct analysis for each land cover while using one observation
per grid box. The updated values are aggregated by computing
a weighted average.
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In this study, it is demonstrated that the assimilation scheme works
effectively within the ISBA-A-gs model over a four-year period
(2008–2011). The EKF is able to extract useful information from the
data signal at the grid scale and distribute the root-zone soil
moisture and LAI increments throughout the mosaic structure of the
model. The impact of the assimilation on the vegetation phenology and
on the water and carbon fluxes varies from one season to another. The
spring drought of 2011 is an interesting case study of the
potential of the assimilation to improve drought
monitoring. A comparison between simulated and in situ soil moisture
gathered at the twelve SMOSMANIA (Soil Moisture Observing
System–Meteorological Automatic Network Integrated Application) stations shows improved anomaly
correlations for eight stations
Global Carleman inequalities for parabolic systems and applications to controllability
This paper has been conceived as an overview on the controllability properties of some relevant (linear and nonlinear) parabolic systems. Specifically, we deal with the null controllability and the exact controllability to the trajectories. We try to explain the role played by the observability
inequalities in this context and the need of global Carleman estimates. We also recall the main ideas used to overcome the difficulties motivated by nonlinearities. First, we considered the classical heat equation with Dirichlet conditions and distributed controls. Then we analyze recent extensions to
other linear and semilinear parabolic systems and/or boundary controls. Finally, we review the controllability properties for the Stokes and Navier–Stokes equations that are known to date. In this context, we have paid special attention to obtaining the necessary Carleman estimates. Some open questions are mentioned throughout the paper. We hope that this unified presentation will be useful for those researchers interested in the field.Ministerio de Educación y Cienci
Youngsters do not pay attention to conversational rules: is this so for nonhuman primates?
The potentiality to find precursors of human language in nonhuman primates is questioned because of differences related to the genetic determinism of human and nonhuman primate acoustic structures. Limiting the debate to production and acoustic plasticity might have led to underestimating parallels between human and nonhuman primates. Adult-young differences concerning vocal usage have been reported in various primate species. A key feature of language is the ability to converse, respecting turn-taking rules. Turn-taking structures some nonhuman primates' adult vocal exchanges, but the development and the cognitive relevancy of this rule have never been investigated in monkeys. Our observations of Campbell's monkeys' spontaneous vocal utterances revealed that juveniles broke the turn-taking rule more often than did experienced adults. Only adults displayed different levels of interest when hearing playbacks of vocal exchanges respecting or not the turn-taking rule. This study strengthens parallels between human conversations and nonhuman primate vocal exchanges
Global attractors for Cahn-Hilliard equations with non constant mobility
We address, in a three-dimensional spatial setting, both the viscous and the
standard Cahn-Hilliard equation with a nonconstant mobility coefficient. As it
was shown in J.W. Barrett and J.W. Blowey, Math. Comp., 68 (1999), 487-517, one
cannot expect uniqueness of the solution to the related initial and boundary
value problems. Nevertheless, referring to J. Ball's theory of generalized
semiflows, we are able to prove existence of compact quasi-invariant global
attractors for the associated dynamical processes settled in the natural
"finite energy" space. A key point in the proof is a careful use of the energy
equality, combined with the derivation of a "local compactness" estimate for
systems with supercritical nonlinearities, which may have an independent
interest. Under growth restrictions on the configuration potential, we also
show existence of a compact global attractor for the semiflow generated by the
(weaker) solutions to the nonviscous equation characterized by a "finite
entropy" condition
Weak formulation for singular diffusion equation with dynamic boundary condition
In this paper, we propose a weak formulation of the singular diffusion
equation subject to the dynamic boundary condition. The weak formulation is
based on a reformulation method by an evolution equation including the
subdifferential of a governing convex energy. Under suitable assumptions, the
principal results of this study are stated in forms of Main Theorems A and B,
which are respectively to verify: the adequacy of the weak formulation; the
common property between the weak solutions and those in regular problems of
standard PDEs.Comment: 23 page
South Korea's automotive labour regime, Hyundai Motors’ global production network and trade‐based integration with the European Union
This article explores the interrelationship between global production networks(GPNs) and free trade agreements (FTAs) in the South Korean auto industry and its employment relations. It focuses on the production network of the Hyundai Motor Group (HMG) — the third biggest automobile manufacturer in the world — and the FTA between the EU and South Korea. This was the first of the EU’s ‘new generation’ FTAs, which among other things contained provisions designed to protect and promote labour standards. The article’s argument is twofold. First, that HMG’s production network and Korea’s political economy (of which HMG is a crucial part) limited the possibilities for the FTA’s labour provisions to take effect. Second, that the commercial provisions in this same FTA simultaneously eroded HMG’s domestic market and corporate profitability, leading to adverse consequences for auto workers in the more
insecure and low-paid jobs. In making this argument, the article advances a multiscalar conceptualization of the labour regime as an analytical intermediary between GPNs and FTAs. It also provides one of the first empirical studies of the EU–South Korea FTA in terms of employment relations, drawing on 105 interviews with trade unions, employer associations, automobile companies and state officials across both parties
Data mining tool for academic data exploitation: publication report on engineering students profiles
This report summarizes the findings of the project SPEET. It relies on the initial document
generated as Intellectual Output #1 and the results obtained by application of the IT tools developed in Intellectual Output #2, and Intellectual Output #3 to the academic data provided by the partner institutions.
The main objectives of applying analytic techniques to evaluate the academic data sources can be categorized as follows: Improve Student Results; Create Mass-customized Programs; Improve the Learning Experience in Real-time; Reduce Dropouts and Increase Results.info:eu-repo/semantics/publishedVersio
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