4,599 research outputs found
Lamellae Stability in Confined Systems with Gravity
The microphase separation of a diblock copolymer melt confined by hard walls
and in the presence of a gravitational field is simulated by means of a cell
dynamical system model. It is found that the presence of hard walls normal to
the gravitational field are key ingredients to the formation of well ordered
lamellae in BCP melts. To this effect the currents in the directions normal and
parallel to the field are calculated along the interface of a lamellar domain,
showing that the formation of lamellae parallel to the hard boundaries and
normal to the field correspond to the stable configuration. Also, it is found
thet the field increases the interface width.Comment: 4 pages, 2 figures, submitted to Physical Review
A study of the effectiveness of telepsychiatry-based culturally sensitive collaborative treatment of depressed Chinese Americans
<p>Abstract</p> <p>Background</p> <p>Chinese American patients with Major Depressive Disorder (MDD) tend to underutilize mental health services and are more likely to seek help in primary care settings than from mental health specialists. Our team has reported that Culturally Sensitive Collaborative Treatment (CSCT) is effective in improving recognition and treatment engagement of depressed Chinese Americans in primary care. The current study builds on this prior research by incorporating telemedicine technology into the CSCT model.</p> <p>Methods/Design</p> <p>We propose a randomized controlled trial to evaluate the acceptability and effectiveness of a telepsychiatry-based culturally sensitive collaborative treatment (T-CSCT) intervention targeted toward Chinese Americans. Patients meeting the study's eligibility criteria will receive either treatment as usual or the intervention under investigation. The six-month intervention involves: 1) an initial psychiatric interview using a culturally sensitive protocol via videoconference; 2) eight scheduled phone visits with a care manager assigned to the patient, who will monitor the patient's progress, as well as medication side effects and dosage if applicable; and 3) collaboration between the patient's PCP, psychiatrist, and care manager. Outcome measures include depressive symptom severity as well as patient and PCP satisfaction with the telepsychiatry-based care management service.</p> <p>Discussion</p> <p>The study investigates the T-CSCT model, which we believe will increase the feasibility and practicality of the CSCT model by adopting telemedicine technology. We anticipate that this model will expand access to culturally competent psychiatrists fluent in patients' native languages to improve treatment of depressed minority patients in primary care settings.</p> <p>Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00854542">NCT00854542</a></p
Macrorealism from entropic Leggett-Garg inequalities
We formulate entropic Leggett-Garg inequalities, which place constraints on
the statistical outcomes of temporal correlations of observables. The
information theoretic inequalities are satisfied if macrorealism holds. We show
that the quantum statistics underlying correlations between time-separated spin
component of a quantum rotor mimics that of spin correlations in two spatially
separated spin- particles sharing a state of zero total spin. This brings
forth the violation of the entropic Leggett-Garg inequality by a rotating
quantum spin- system in similar manner as does the entropic Bell inequality
(Phys. Rev. Lett. 61, 662 (1988)) by a pair of spin- particles forming a
composite spin singlet state.Comment: 5 pages, RevTeX, 2 eps figures, Accepted for publication in Phys.
Rev.
Observing two dark accelerators around the Galactic Centre with Fermi Large Area Telescope
We report the results from a detailed ray investigation in the field
of two "dark accelerators", HESS J1745-303 and HESS J1741-302, with years
of data obtained by the Fermi Large Area Telescope. For HESS J1745-303, we
found that its MeV-GeV emission is mainly originated from the "Region A" of the
TeV feature. Its ray spectrum can be modeled with a single power-law
with a photon index of from few hundreds MeV to TeV. Moreover,
an elongated feature, which extends from "Region A" toward northwest for
, is discovered for the first time. The orientation of this
feature is similar to that of a large scale atomic/molecular gas distribution.
For HESS J1741-302, our analysis does not yield any MeV-GeV counterpart for
this unidentified TeV source. On the other hand, we have detected a new point
source, Fermi J1740.1-3013, serendipitously. Its spectrum is apparently curved
which resembles that of a ray pulsar. This makes it possibly
associated with PSR B1737-20 or PSR J1739-3023.Comment: 11 pages, 7 figures, 2 tables, accepted for publication in MNRA
Phase Separation Kinetics in a Model with Order-Parameter Dependent Mobility
We present extensive results from 2-dimensional simulations of phase
separation kinetics in a model with order-parameter dependent mobility. We find
that the time-dependent structure factor exhibits dynamical scaling and the
scaling function is numerically indistinguishable from that for the
Cahn-Hilliard (CH) equation, even in the limit where surface diffusion is the
mechanism for domain growth. This supports the view that the scaling form of
the structure factor is "universal" and leads us to question the conventional
wisdom that an accurate representation of the scaled structure factor for the
CH equation can only be obtained from a theory which correctly models bulk
diffusion.Comment: To appear in PRE, figures available on reques
Optimal Location of Sources in Transportation Networks
We consider the problem of optimizing the locations of source nodes in
transportation networks. A reduction of the fraction of surplus nodes induces a
glassy transition. In contrast to most constraint satisfaction problems
involving discrete variables, our problem involves continuous variables which
lead to cavity fields in the form of functions. The one-step replica symmetry
breaking (1RSB) solution involves solving a stable distribution of functionals,
which is in general infeasible. In this paper, we obtain small closed sets of
functional cavity fields and demonstrate how functional recursions are
converted to simple recursions of probabilities, which make the 1RSB solution
feasible. The physical results in the replica symmetric (RS) and the 1RSB
frameworks are thus derived and the stability of the RS and 1RSB solutions are
examined.Comment: 38 pages, 18 figure
Spinodal Decomposition and the Tomita Sum Rule
The scaling properties of a phase-ordering system with a conserved order
parameter are studied. The theory developed leads to scaling functions
satisfying certain general properties including the Tomita sum rule. The theory
also gives good agreement with numerical results for the order parameter
scaling function in three dimensions. The values of the associated
nonequilibrium decay exponents are given by the known lower bounds.Comment: 15 pages, 6 figure
Phase-ordering of conserved vectorial systems with field-dependent mobility
The dynamics of phase-separation in conserved systems with an O(N) continuous
symmetry is investigated in the presence of an order parameter dependent
mobility M(\phi)=1-a \phi^2. The model is studied analytically in the framework
of the large-N approximation and by numerical simulations of the N=2, N=3 and
N=4 cases in d=2, for both critical and off-critical quenches. We show the
existence of a new universality class for a=1 characterized by a growth law of
the typical length L(t) ~ t^{1/z} with dynamical exponent z=6 as opposed to the
usual value z=4 which is recovered for a<1.Comment: RevTeX, 8 pages, 13 figures, to be published in Phys. Rev.
Two-scale competition in phase separation with shear
The behavior of a phase separating binary mixture in uniform shear flow is
investigated by numerical simulations and in a renormalization group (RG)
approach. Results show the simultaneous existence of domains of two
characteristic scales. Stretching and cooperative ruptures of the network
produce a rich interplay where the recurrent prevalence of thick and thin
domains determines log-time periodic oscillations. A power law growth of the average domain size, with and in the flow and shear direction respectively, is shown to be obeyed.Comment: 5 Revtex pages, 4 figure
Stability of a Nonequilibrium Interface in a Driven Phase Segregating System
We investigate the dynamics of a nonequilibrium interface between coexisting
phases in a system described by a Cahn-Hilliard equation with an additional
driving term. By means of a matched asymptotic expansion we derive equations
for the interface motion. A linear stability analysis of these equations
results in a condition for the stability of a flat interface. We find that the
stability properties of a flat interface depend on the structure of the driving
term in the original equation.Comment: 14 pages Latex, 1 postscript-figur
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