2,433 research outputs found
Inâout decomposition of boundary integral equations
We propose a reformulation of the boundary integral equations for the Helmholtz equation in a domain in terms of incoming and outgoing boundary waves. We obtain transfer operator descriptions which are exact and thus incorporate features such as diffraction and evanescent coupling; these effects are absent in the well-known semiclassical transfer operators in the sense of Bogomolny. It has long been established that transfer operators are equivalent to the boundary integral approach within semiclassical approximation. Exact treatments have been restricted to specific boundary conditions (such as Dirichlet or Neumann). The approach we propose is independent of the
boundary conditions, and in fact allows one to decouple entirely the problem of propagating waves across the interior from the problem of reflecting waves at
the boundary. As an application, we show how the decomposition may be used to calculate GoosâHaenchen shifts of ray dynamics in billiards with variable boundary conditions and for dielectric cavities
Implementing Distributed Controllers for Systems with Priorities
Implementing a component-based system in a distributed way so that it ensures
some global constraints is a challenging problem. We consider here abstract
specifications consisting of a composition of components and a controller given
in the form of a set of interactions and a priority order amongst them. In the
context of distributed systems, such a controller must be executed in a
distributed fashion while still respecting the global constraints imposed by
interactions and priorities.
We present in this paper an implementation of an algorithm that allows a
distributed execution of systems with (binary) interactions and priorities. We
also present a comprehensive simulation analysis that shows how sensitive to
changes our algorithm is, in particular changes related to the degree of
conflict in the system.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499
Thermoregulation is not impaired in breast cancer survivors during moderate-intensity exercise performed in warm and hot environments
This study aimed to assess how female breast cancer survivors (BCS) respond physiologically, hematologically, and perceptually to exercise under heat stress compared to females with no history of breast cancer (CON). Twentyâone females (9 BCS and 12 CON [age; 54 ± 7 years, stature; 167 ± 6 cm, body mass; 68.1 ± 7.62 kg, and body fat; 30.9 ± 3.8%]) completed a warm (25â, 50% relative humidity, RH) and hot (35â, 50%RH) trial in a repeatedâmeasures crossover design. Trials consisted of 30 min of rest, 30 min of walking at 4 metabolic equivalents, and a 6âminute walk test (6MWT). Physiological measurements (core temperature (T (re)), skin temperature (T (skin)), heart rate (HR), and sweat analysis) and perceptual rating scales (ratings of perceived exertion, thermal sensation [whole body and localized], and thermal comfort) were taken at 5â and 10âmin intervals throughout, respectively. Venous blood samples were taken before and after to assess; ILâ6, ILâ10, CRP, IFNâÎł, and TGFâÎČ(1). All physiological markers were higher during the 35 versus 25â trial; T (re) (~0.25â, p = 0.002), T (skin) (~3.8â, p  0.05). Both groups covered a greater 6MWT distance in 25 versus 35â (by ~200 m; p = 0.003). Nevertheless, the control group covered more distance than BCS, regardless of environmental temperature (by ~400 m, p = 0.03). Thermoregulation was not disadvantaged in BCS compared to controls during moderateâintensity exercise under heat stress. However, selfâpaced exercise performance was reduced for BCS regardless of environmental temperature
Creating, moving and merging Dirac points with a Fermi gas in a tunable honeycomb lattice
Dirac points lie at the heart of many fascinating phenomena in condensed
matter physics, from massless electrons in graphene to the emergence of
conducting edge states in topological insulators [1, 2]. At a Dirac point, two
energy bands intersect linearly and the particles behave as relativistic Dirac
fermions. In solids, the rigid structure of the material sets the mass and
velocity of the particles, as well as their interactions. A different, highly
flexible approach is to create model systems using fermionic atoms trapped in
the periodic potential of interfering laser beams, a method which so far has
only been applied to explore simple lattice structures [3, 4]. Here we report
on the creation of Dirac points with adjustable properties in a tunable
honeycomb optical lattice. Using momentum-resolved interband transitions, we
observe a minimum band gap inside the Brillouin zone at the position of the
Dirac points. We exploit the unique tunability of our lattice potential to
adjust the effective mass of the Dirac fermions by breaking inversion symmetry.
Moreover, changing the lattice anisotropy allows us to move the position of the
Dirac points inside the Brillouin zone. When increasing the anisotropy beyond a
critical limit, the two Dirac points merge and annihilate each other - a
situation which has recently attracted considerable theoretical interest [5-9],
but seems extremely challenging to observe in solids [10]. We map out this
topological transition in lattice parameter space and find excellent agreement
with ab initio calculations. Our results not only pave the way to model
materials where the topology of the band structure plays a crucial role, but
also provide an avenue to explore many-body phases resulting from the interplay
of complex lattice geometries with interactions [11, 12]
a protocol for developing a patient-reported outcome measurement instrument
Introduction: There is no consensus about what constitutes the most
appropriate patient-reported outcome measurement (PROM) instrument for
measuring physical function in patients with rheumatic hand conditions.
Existing instruments lack psychometric testing and vary in feasibility and
their psychometric qualities. We aim to develop a PROM instrument to assess
hand-related physical function in rheumatic hand conditions. Methods and
analysis: We will perform a systematic search to identify existing PROMs to
rheumatic hand conditions, and select items relevant for hand-related physical
function as well as those items from the Patient Reported Outcomes Measurement
Information System (PROMIS) Physical Function (PF) item bank that are relevant
to patients with rheumatic hand conditions. Selection will be based on
consensus among reviewers. Content validity of selected items will be
established through the use of focus groups. If patients deem necessary, we
will develop new items based on the patients' input. We will examine whether
it is valid to score all selected and developed items on the same scale as the
original items from the PROMIS PF item bank. Our analyses will follow the
methods used for calibrating the original PROMIS PF item bank in US samples,
which were largely based on the general PROMIS approach. Ethics and
dissemination: This study will be carried out in accordance with the Helsinki
Declaration. Ethics approvals will be obtained where necessary, and signed
informed consent will be obtained from all participants. We aim to disseminate
the results of the study through publication in international peer-reviewed
journals and at international conferences
Observation of enhanced chiral asymmetries in the inner-shell photoionization of uniaxially oriented methyloxirane enantiomers
Most large molecules are chiral in their structure: they exist as two
enantiomers, which are mirror images of each other. Whereas the rovibronic
sublevels of two enantiomers are almost identical, it turns out that the
photoelectric effect is sensitive to the absolute configuration of the ionized
enantiomer - an effect termed Photoelectron Circular Dichroism (PECD). Our
comprehensive study demonstrates that the origin of PECD can be found in the
molecular frame electron emission pattern connecting PECD to other fundamental
photophysical effects as the circular dichroism in angular distributions
(CDAD). Accordingly, orienting a chiral molecule in space enhances the PECD by
a factor of about 10
Dose-finding study of valspodar (PSC 833) with daunorubicin and cytarabine to reverse multidrug resistance in elderly patients with previously untreated acute myeloid leukemia
Introduction: This trial was designed to determine the maximum tolerated dose of intravenous daunorubicin (DNR) in combination with valspodar and to test the feasibility of P-glycoprotein modulation using valspodar in elderly patients with previously untreated acute myelogenous leukemia receiving standard induction chemotherapy. Methods: Patients â„60 years of age with previously untreated AML received valspodar (10 mg/kg/24 h by continuous intravenous infusion [CIV] on days 1-4 with a 2-mg/kg loading dose on day 1) in conjunction with two cycles of induction chemotherapy consisting of cytarabine (200 mg/m2 CIV on days 1-7), and DNR (35 mg/m2 [cohort 1] or 45 mg/m2 [cohort 2] on days 1-3, intravenous bolus). Patients were assessed for dose-limiting toxicities (DLT), response rate, event-free and overall survival, and pharmacokinetics of valspodar and DNR. Results: Valspodar was well tolerated at the lower DNR dose level (ie, 35 mg/m2) resulting in a 21% rate of DLT and only three toxic deaths. Treatment-related mortality was unacceptably high at the 45 mg/m2 DNR dose level. The complete response rate was 49% overall and similar in both cohorts. The median overall survival of patients was 333 days in cohort 1 compared to 98 days in cohort 2. At baseline, 70% of assessable patients were P-glycoprotein positive. Conclusion: Substantial inhibition of P-glycoprotein activity can be achieved in this patient population at clinically tolerable doses of valspodar and DNR. The maximum tolerated dose of DNR was established as 35 mg/m2. This regimen is being further evaluated in phase III trials.</p
Hand-related physical function in rheumatic hand conditions:a protocol for developing a patient-reported outcome measurement instrument
Introduction: There is no consensus about what constitutes the most appropriate patient-reported outcome measurement (PROM) instrument for measuring physical function in patients with rheumatic hand conditions. Existing instruments lack psychometric testing and vary in feasibility and their psychometric qualities. We aim to develop a PROM instrument to assess hand-related physical function in rheumatic hand conditions.
Methods and analysis: We will perform a systematic search to identify existing PROMs to rheumatic hand conditions, and select items relevant for hand-related physical function as well as those items from the Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) item bank that are relevant to patients with rheumatic hand conditions. Selection will be based on consensus among reviewers. Content validity of selected items will be established through the use of focus groups. If patients deem necessary, we will develop new items based on the patients' input. We will examine whether it is valid to score all selected and developed items on the same scale as the original items from the PROMIS PF item bank. Our analyses will follow the methods used for calibrating the original PROMIS PF item bank in US samples, which were largely based on the general PROMIS approach.
Ethics and dissemination: This study will be carried out in accordance with the Helsinki Declaration. Ethics approvals will be obtained where necessary, and signed informed consent will be obtained from all participants. We aim to disseminate the results of the study through publication in international peer-reviewed journals and at international conferences
Long-Lived Individuals Show a Lower Burden of Variants Predisposing to Age-Related Diseases and a Higher Polygenic Longevity Score
Longevity is a complex phenotype influenced by both environmental and genetic factors. The genetic contribution is estimated at about 25%. Despite extensive research efforts, only a few longevity genes have been validated across populations. Long-lived individuals (LLI) reach extreme ages with a relative low prevalence of chronic disability and major age-related diseases (ARDs). We tested whether the protection from ARDs in LLI can partly be attributed to genetic factors by calculating polygenic risk scores (PRSs) for seven common late-life diseases (Alzheimer's disease (AD), atrial fibrillation (AF), coronary artery disease (CAD), colorectal cancer (CRC), ischemic stroke (ISS), Parkinson's disease (PD) and type 2 diabetes (T2D)). The examined sample comprised 1351 German LLI (â„94 years, including 643 centenarians) and 4680 German younger controls. For all ARD-PRSs tested, the LLI had significantly lower scores than the younger control individuals (areas under the curve (AUCs): ISS = 0.59, p = 2.84 Ă 10-35; AD = 0.59, p = 3.16 Ă 10-25; AF = 0.57, p = 1.07 Ă 10-16; CAD = 0.56, p = 1.88 Ă 10-12; CRC = 0.52, p = 5.85 Ă 10-3; PD = 0.52, p = 1.91 Ă 10-3; T2D = 0.51, p = 2.61 Ă 10-3). We combined the individual ARD-PRSs into a meta-PRS (AUC = 0.64, p = 6.45 Ă 10-15). Furthermore, the inclusion of nine markers from the excluded region (not in LD with each other) plus the APOE haplotype into the model raised the AUC from 0.55 to 0.61. Thus, our results highlight the importance of TOMM40/APOE/APOC1 as a longevity hub
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