5,150 research outputs found
Parallel Graph Partitioning for Complex Networks
Processing large complex networks like social networks or web graphs has
recently attracted considerable interest. In order to do this in parallel, we
need to partition them into pieces of about equal size. Unfortunately, previous
parallel graph partitioners originally developed for more regular mesh-like
networks do not work well for these networks. This paper addresses this problem
by parallelizing and adapting the label propagation technique originally
developed for graph clustering. By introducing size constraints, label
propagation becomes applicable for both the coarsening and the refinement phase
of multilevel graph partitioning. We obtain very high quality by applying a
highly parallel evolutionary algorithm to the coarsened graph. The resulting
system is both more scalable and achieves higher quality than state-of-the-art
systems like ParMetis or PT-Scotch. For large complex networks the performance
differences are very big. For example, our algorithm can partition a web graph
with 3.3 billion edges in less than sixteen seconds using 512 cores of a high
performance cluster while producing a high quality partition -- none of the
competing systems can handle this graph on our system.Comment: Review article. Parallelization of our previous approach
arXiv:1402.328
Transcriptional regulation of prostate kallikrein-like genes by androgen.
Using gene-specific synthetic oligonucleotides the
expression and regulation of kallikrein-like genes in
the human prostatic cancer cell line LNCaP were
studied. Prostate-specific antigen (PSA) and human
glandular kallikrein (hGK-1) together constitute a
subfamily of serine proteases exclusively produced
in the human prostate. RNA analysis revealed that
both genes are expressed in LNCaP cells with PSA
basal levels being 2-fold higher than hGK-1 levels.
Both mRNAs are induced over a period of 24 h in
the presence of 3.3 nM of the synthetic androgen
mibolerone. Stimulation of PSA RNA is about 5-
fold,whereas hGK-1 stimulation is less pronounced.
Nuclear run-on analysis revealed that androgen induction
of kallikrein-like genes in LNCaP cells is a
rapid event (c3 h) occurring at the level of transcription
initiation. Treatment of cells with cycloheximide
demonstrates that, while PSA/hGK-1 basal transcription
strictly depends on continuous protein synthesis,
transcriptional induction by androgen does
not. This suggests the direct involvement of the
androgen receptor in the induction process independent
of additional labile protein factors necessary
for kallikrein basal transcription. A binding motif
is present in the PSA and hGK-1 promoters, closely
resembling the consensus sequence for steroidresponsive
elements. The androgen antagonist cyproterone
acetate was also able to stimulate transcription
of kallikrein-like genes in LNCaP cells. In
contrast, androgen-dependent transcriptional
suppression of the protooncogene c-myc was
strongly counteracted by cyproterone acetate. Thus,
antiandrogens act differentially on androgen-regulated
prostate-specific (PSA, hGK-1) and growthrelated
(c-myc) gene expression in LNCaP cells
Longitudinal qualitative exploration of cancer information-seeking experiences across the disease trajectory: the INFO-SEEK protocol
Introduction Î substantial corpus of literature has sought to describe the information-seeking behaviour of patients with cancer. Yet, available evidence comes mainly from cross-sectional studies, which provide âsnapshotsâ of patientsâ information needs and information-seeking styles at a single time point. Only a few longitudinal studies currently exist; however, these are quantitative in nature and, despite successfully documenting changes in patientsâ information needs throughout the clinical course of cancer, they have failed to provide an evidence-based interpretation of the causes and consequences of change. The goal of this study is threefold: First, we wish to provide a holistic understanding of how cancer information-seeking behaviour may evolve across different stages of the patient journey. Second, we will seek to elucidate the contextual and intervening conditions that may affect possible changes in information seeking. Third, we will attempt to identify what the consequences of these changes are, while heightening their implications for clinical practice and policy.
Methods and analysis We will carry out a longitudinal qualitative study, based on face-to-face, in-depth interviews with approximately 25 individuals diagnosed with cancer. Patients will be recruited from 2 oncology hospitals located in Ticino, Switzerland, and will be interviewed at 3 different time points: (1) within 2â
weeks after receiving the cancer diagnosis; (2) within 2â
weeks after their initial treatment; and (3) 6â
months after their initial treatment. All interviews will be recorded and transcribed verbatim. A grounded theory approach will be used for the analysis of the data.
Ethics and dissemination The study protocol has been approved by the Ethics Committee of Canton Ticino (CE 2813). Participation in the study will be voluntary, and confidentiality and anonymity ensured. Prior to study participation, patients will be asked to provide signed informed consent. Findings will be disseminated in international peer-reviewed journals and presented in relevant conferences
Stress correlations of dislocations in a double-pileup configuration: a continuum dislocation density approach â complas XII
Dislocation motion in the crystal lattice of materials is the basis for macroscopic plasticity. While continuum models for describing the role of dislocations in plasticity have existed for decades, only recently have the mathematical tools become available to describe ensembles of moving, oriented lines. These tools have allowed for the creation of a Continuum Dislocation Dynamics (CDD) theory describing a second-order dislocation density tensor, a higher order analog of the classical dislocation density tensor, and its evolution in time. In order to reduce the computational complexity of the theory, a simpliïŹed theory has also been developed, which more readily allows for a numerical implementation, useful for describing larger systems of dislocations. In order to construct a self-consistent implementation, several issues have to be resolved including calculation of the stress ïŹeld of a system of dislocations, coarse graining, and boundary values. The present work deals with the implementation including treatment of the near- and far-ïŹeld stresses caused by the dislocation density tensor as well as boundary value considerations. The implementation is then applied to a few simple benchmark problems, notably the double pileup of dislocations in 1D. Applications to more general problems are considered, as well as comparisons with analytical solutions to classical dislocation problems. Focus is placed on problems where analytical solutions as well as simulations of discrete dislocations are known which act, along with experimental results, as the basis of comparison to determine the validity of the results
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