47,628 research outputs found
Boundedness of Pseudodifferential Operators on Banach Function Spaces
We show that if the Hardy-Littlewood maximal operator is bounded on a
separable Banach function space and on its associate space
, then a pseudodifferential operator
is bounded on whenever the symbol belongs to the
H\"ormander class with ,
or to the the Miyachi class
with ,
. This result is applied to the case of
variable Lebesgue spaces .Comment: To appear in a special volume of Operator Theory: Advances and
Applications dedicated to Ant\'onio Ferreira dos Santo
Lower plasma levels of selenium and glutathione in smear-positive tuberculosis patients in Malawi
No Abstract
Complexity and Inapproximability Results for Parallel Task Scheduling and Strip Packing
We study the Parallel Task Scheduling problem with a
constant number of machines. This problem is known to be strongly NP-complete
for each , while it is solvable in pseudo-polynomial time for each . We give a positive answer to the long-standing open question whether
this problem is strongly -complete for . As a second result, we
improve the lower bound of for approximating pseudo-polynomial
Strip Packing to . Since the best known approximation algorithm
for this problem has a ratio of , this result
narrows the gap between approximation ratio and inapproximability result by a
significant step. Both results are proven by a reduction from the strongly
-complete problem 3-Partition
An output-sensitive algorithm for the minimization of 2-dimensional String Covers
String covers are a powerful tool for analyzing the quasi-periodicity of
1-dimensional data and find applications in automata theory, computational
biology, coding and the analysis of transactional data. A \emph{cover} of a
string is a string for which every letter of lies within some
occurrence of . String covers have been generalized in many ways, leading to
\emph{k-covers}, \emph{-covers}, \emph{approximate covers} and were
studied in different contexts such as \emph{indeterminate strings}.
In this paper we generalize string covers to the context of 2-dimensional
data, such as images. We show how they can be used for the extraction of
textures from images and identification of primitive cells in lattice data.
This has interesting applications in image compression, procedural terrain
generation and crystallography
L-Arginine promotes gut hormone release and reduces food intake in rodents
Aims: To investigate the anorectic effect of Lāarginine (LāArg) in rodents.
Methods: We investigated the effects of LāArg on food intake, and the role of the anorectic gut hormones glucagonālike peptideā1 (GLPā1) and peptide YY (PYY), the Gāproteinācoupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents.
Results: Oral gavage of LāArg reduced food intake in rodents, and chronically reduced cumulative food intake in dietāinduced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. LāArg stimulated GLPā1 and PYY release in vitro and in vivo. Pharmacological blockade of GLPā1 and PYY receptors did not influence the anorectic effect of LāArg. LāArgāmediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of LāArg suppressed food intake in rats.
Conclusions: LāArg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of LāArg is unlikely to be mediated by GLPā1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of LāArg suppressed food intake in rats, suggesting that LāArg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which LāArg suppresses food intake and its utility in the treatment of obesity
Dwarf Nova V1040 Centauri and Variable Stars in its Vicinity
We present the results of a photometric campaign of the dwarf nova V1040 Cen.
The light curve shows two normal outbursts with recurrence time ~ 40 days and
amplitude ~ 2.5 mag. Quiescence data show oscillations with periods in the
range ~ 0.1 days (2.4 h) to ~ 0.5 days (12 h) of unknown origin. We measured
the orbital period of V1040 Cen to be P_orb=0.060458(80) days (1.451+-0.002 h).
Based on the M_v-P_orb relation we found the distance of V1040 Cen to be
137+-31 pc. In this paper we also report the detection of eleven new variable
stars in the field of the monitored dwarf nova.Comment: 7 figures and 2 tables, accepted for publication in Acta Astronomic
A Goal-based Framework for Contextual Requirements Modeling and Analysis
Requirements Engineering (RE) research often ignores, or presumes a uniform nature of the context in which the system operates. This assumption is no longer valid in emerging computing paradigms, such as ambient, pervasive and ubiquitous computing, where it is essential to monitor and adapt to an inherently varying context. Besides influencing the software, context may influence stakeholders' goals and their choices to meet them. In this paper, we propose a goal-oriented RE modeling and reasoning framework for systems operating in varying contexts. We introduce contextual goal models to relate goals and contexts; context analysis to refine contexts and identify ways to verify them; reasoning techniques to derive requirements reflecting the context and users priorities at runtime; and finally, design time reasoning techniques to derive requirements for a system to be developed at minimum cost and valid in all considered contexts. We illustrate and evaluate our approach through a case study about a museum-guide mobile information system
Graphene-based photovoltaic cells for near-field thermal energy conversion
Thermophotovoltaic devices are energy-conversion systems generating an
electric current from the thermal photons radiated by a hot body. In far field,
the efficiency of these systems is limited by the thermodynamic
Schockley-Queisser limit corresponding to the case where the source is a black
body. On the other hand, in near field, the heat flux which can be transferred
to a photovoltaic cell can be several orders of magnitude larger because of the
contribution of evanescent photons. This is particularly true when the source
supports surface polaritons. Unfortunately, in the infrared where these systems
operate, the mismatch between the surface-mode frequency and the semiconductor
gap reduces drastically the potential of this technology. Here we show that
graphene-based hybrid photovoltaic cells can significantly enhance the
generated power paving the way to a promising technology for an intensive
production of electricity from waste heat.Comment: 5 pages, 4 figure
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The JAK inhibitor tofacitinib suppresses synovial JAK1-STAT signalling in rheumatoid arthritis.
ObjectiveTofacitinib is an oral Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis (RA). The pathways affected by tofacitinib and the effects on gene expression in situ are unknown. Therefore, tofacitinib effects on synovial pathobiology were investigated.MethodsA randomised, double-blind, phase II serial synovial biopsy study (A3921073; NCT00976599) in patients with RA with an inadequate methotrexate response. Patients on background methotrexate received tofacitinib 10ā
mg twice daily or placebo for 28ā
days. Synovial biopsies were performed on Days -7 and 28 and analysed by immunoassay or quantitative PCR. Clinical response was determined by disease activity score and European League Against Rheumatism (EULAR) response on Day 28 in A3921073, and at Month 3 in a long-term extension study (A3921024; NCT00413699).ResultsTofacitinib exposure led to EULAR moderate to good responses (11/14 patients), while placebo was ineffective (1/14 patients) on Day 28. Tofacitinib treatment significantly reduced synovial mRNA expression of matrix metalloproteinase (MMP)-1 and MMP-3 (p<0.05) and chemokines CCL2, CXCL10 and CXCL13 (p<0.05). No overall changes were observed in synovial inflammation score or the presence of T cells, B cells or macrophages. Changes in synovial phosphorylation of signal transducer and activator of transcription 1 (STAT1) and STAT3 strongly correlated with 4-month clinical responses (p<0.002). Tofacitinib significantly decreased plasma CXCL10 (p<0.005) at Day 28 compared with placebo.ConclusionsTofacitinib reduces metalloproteinase and interferon-regulated gene expression in rheumatoid synovium, and clinical improvement correlates with reductions in STAT1 and STAT3 phosphorylation. JAK1-mediated interferon and interleukin-6 signalling likely play a key role in the synovial response.Trial registration numberNCT00976599
Prediction of the Atomization Energy of Molecules Using Coulomb Matrix and Atomic Composition in a Bayesian Regularized Neural Networks
Exact calculation of electronic properties of molecules is a fundamental step
for intelligent and rational compounds and materials design. The intrinsically
graph-like and non-vectorial nature of molecular data generates a unique and
challenging machine learning problem. In this paper we embrace a learning from
scratch approach where the quantum mechanical electronic properties of
molecules are predicted directly from the raw molecular geometry, similar to
some recent works. But, unlike these previous endeavors, our study suggests a
benefit from combining molecular geometry embedded in the Coulomb matrix with
the atomic composition of molecules. Using the new combined features in a
Bayesian regularized neural networks, our results improve well-known results
from the literature on the QM7 dataset from a mean absolute error of 3.51
kcal/mol down to 3.0 kcal/mol.Comment: Under review ICANN 201
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