1,755 research outputs found
Phase-diagram for Irregular and Non-Symmetric Cross-linked Polymer Blends
We consider here a blend made of two types of polymers, and , of
different chemical nature. At high temperature the homogeneous mixture is
cross-linked. As the temperature is lowered, the two species try to segregate
but are kept together by the cross-links. We show that for inhomogeneous,
non-regular and non-permanent cross-links, there is a complete segregation at
low temperatures if the system is just weakly cross-linked and partial
segregation, otherwise. We also demonstrate that there is no phase transition
between the homogeneous phase and the microphase for non-symmetric systems. Our
analysis is checked with the experiment.Comment: 10 pages, Revte
Prevalence of vitamin D deficiency in an inpatient population in the Swiss canton of Basel-Country
AIMS: Vitamin D deficiency remains very common in the general population. Adding to the importance of this issue is the discovery that vitamin D plays a role in many other tissues apart from the bone, including muscle, brain, prostate, breast and colon. In this study, we investigated the prevalence of vitamin D deficiency in a large group of patients hospitalised in the cantonal hospital Basel-Country, and analysed the dependence of serum vitamin D concentrations on gender, time of the year and age. METHODS: We retrospectively analysed anonymised data received from the central laboratory of the cantonal hospital Basel-Country. The pool of data contains values obtained between 2013 and 2017 from 8861 patients aged between 18 and 102 years. If sequential measurements were available from a patient, only the first was used for the analyses. Vitamin D deficiency was defined as a serum concentration of <50 nmol/l and severe deficiency as 75 nmol/l. RESULTS: Mean ± standard deviation serum vitamin D concentration was 52.5 ± 30.5 nmol/l, with women having a higher mean of 55.5 ± 31.5 nmol/l as compared with 48.1 ± 28.6 nmol/l in men (p <10-5). Of the 8861 first measurements taken within the observation period, 4527 (51%) were vitamin D deficient with levels <50 nmol/l, including 1860 (21.0%) with levels <25 nmol/l. There was only a weak positive association of average vitamin D levels with age (p = 0.06). Women reached peak concentrations of 56.9 ± 35.4 nmol/l in the age group 90-102 years, whereas men reached peaks of 50.3 ± 31.9 nmol/l in 50-59-year-olds. Mean autumn and spring concentrations differed less (51.6 ± 29.6 vs 52.7 ± 30.7 nmol/l, respectively, p = 0.38) than mean summer and winter concentrations (57.1 ± 29.5 vs 48.0 ± 31.2 nmol/l, respectively, p 75 nmol/l, only 22.1% of measured values indicated adequate vitamin D levels. This issue should be addressed in order to improve quality of life and reduce medical costs.
Scalable Parallel Numerical Constraint Solver Using Global Load Balancing
We present a scalable parallel solver for numerical constraint satisfaction
problems (NCSPs). Our parallelization scheme consists of homogeneous worker
solvers, each of which runs on an available core and communicates with others
via the global load balancing (GLB) method. The parallel solver is implemented
with X10 that provides an implementation of GLB as a library. In experiments,
several NCSPs from the literature were solved and attained up to 516-fold
speedup using 600 cores of the TSUBAME2.5 supercomputer.Comment: To be presented at X10'15 Worksho
Surface-mediated attraction between colloids
We investigate the equilibrium properties of a colloidal solution in contact
with a soft interface. As a result of symmetry breaking, surface effects are
generally prevailing in confined colloidal systems. In this Letter, particular
emphasis is given to surface fluctuations and their consequences on the local
(re)organization of the suspension. It is shown that particles experience a
significant effective interaction in the vicinity of the interface. This
potential of mean force is always attractive, with range controlled by the
surface correlation length. We suggest that, under some circumstances,
surface-induced attraction may have a strong influence on the local particle
distribution
Long-term treatment of postmenopausal osteoporotic women with strontium ranelate : results at 10 years
Peer reviewe
Certainty Closure: Reliable Constraint Reasoning with Incomplete or Erroneous Data
Constraint Programming (CP) has proved an effective paradigm to model and
solve difficult combinatorial satisfaction and optimisation problems from
disparate domains. Many such problems arising from the commercial world are
permeated by data uncertainty. Existing CP approaches that accommodate
uncertainty are less suited to uncertainty arising due to incomplete and
erroneous data, because they do not build reliable models and solutions
guaranteed to address the user's genuine problem as she perceives it. Other
fields such as reliable computation offer combinations of models and associated
methods to handle these types of uncertain data, but lack an expressive
framework characterising the resolution methodology independently of the model.
We present a unifying framework that extends the CP formalism in both model
and solutions, to tackle ill-defined combinatorial problems with incomplete or
erroneous data. The certainty closure framework brings together modelling and
solving methodologies from different fields into the CP paradigm to provide
reliable and efficient approches for uncertain constraint problems. We
demonstrate the applicability of the framework on a case study in network
diagnosis. We define resolution forms that give generic templates, and their
associated operational semantics, to derive practical solution methods for
reliable solutions.Comment: Revised versio
q-Breathers in Discrete Nonlinear Schroedinger arrays with weak disorder
Nonlinearity and disorder are key players in vibrational lattice dynamics,
responsible for localization and delocalization phenomena. -Breathers --
periodic orbits in nonlinear lattices, exponentially localized in the
reciprocal linear mode space -- is a fundamental class of nonlinear oscillatory
modes, currently found in disorder-free systems. In this paper we generalize
the concept of -breathers to the case of weak disorder, taking the Discrete
Nonlinear Schr\"{o}dinger chain as an example. We show that -breathers
retain exponential localization near the central mode, provided that disorder
is sufficiently small. We analyze statistical properties of the instability
threshold and uncover its sensitive dependence on a particular realization.
Remarkably, the threshold can be intentionally increased or decreased by
specifically arranged inhomogeneities. This effect allows us to formulate an
approach to controlling the energy flow between the modes. The relevance to
other model arrays and experiments with miniature mechanical lattices, light
and matter waves propagation in optical potentials is discussed.Comment: 5 pages, 3 figure
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