3,612 research outputs found
Clusters and Recurrence in the Two-Dimensional Zero-Temperature Stochastic Ising Model
We analyze clustering and (local) recurrence of a standard Markov process
model of spatial domain coarsening. The continuous time process, whose state
space consists of assignments of +1 or -1 to each site in , is the
zero-temperature limit of the stochastic homogeneous Ising ferromagnet (with
Glauber dynamics): the initial state is chosen uniformly at random and then
each site, at rate one, polls its 4 neighbors and makes sure it agrees with the
majority, or tosses a fair coin in case of a tie. Among the main results
(almost sure, with respect to both the process and initial state) are: clusters
(maximal domains of constant sign) are finite for times , but the
cluster of a fixed site diverges (in diameter) as ; each of the
two constant states is (positive) recurrent. We also present other results and
conjectures concerning positive and null recurrence and the role of absorbing
states.Comment: 16 pages, 1 figur
Finite-Element Analysis of Temperature Increase in Vascularized Biological Tissues Exposed to RF Sources
A new model of numerical dosimetry is proposed for RF exposure. First, the specific absorption rate (SAR) is computed. Then, the heat transfer governed by the bio-heat equation with convection term is numerically solved by a finite-element method (FEM) procedure considering the discrete vascular model of the perfused tissue. By some manipulations of the FEM equations and by generating an adequate FEM mesh, it is possible to solve the thermal convection in the blood vessels considering a one-dimensional domain embedded in the fully three-dimensional domain where only the thermal diffusion is analyzed
Equivalence of switching linear systems by bisimulation
A general notion of hybrid bisimulation is proposed for the class of switching linear systems. Connections between the notions of bisimulation-based equivalence, state-space equivalence, algebraic and inputâoutput equivalence are investigated. An algebraic characterization of hybrid bisimulation and an algorithmic procedure converging in a finite number of steps to the maximal hybrid bisimulation are derived. Hybrid state space reduction is performed by hybrid bisimulation between the hybrid system and itself. By specializing the results obtained on bisimulation, also characterizations of simulation and abstraction are derived. Connections between observability, bisimulation-based reduction and simulation-based abstraction are studied.\ud
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Targeting leukemic stem cells in chronic myeloid leukemia: Is it worth the effort?
Chronic myeloid leukemia (CML) is a classical example of stem cell cancer since it arises in a multipotent hematopoietic stem cell upon the acquisition of the t(9;22) chromosomal transloca-tion, that converts it into a leukemic stem cell (LSC). The resulting BCRâABL1 fusion gene encodes a deregulated tyrosine kinase that is recognized as the disease driver. Therapy with tyrosine kinase inhibitors (TKIs) eliminates progenitor and more differentiated cells but fails to eradicate quiescent LSCs. Thus, although many patients obtain excellent responses and a proportion of them can even attempt treatment discontinuation (treatment free remission [TFR]) after some years of therapy, LSCs persist, and represent a potentially dangerous reservoir feeding relapse and hampering TFR. Over the past two decades, intensive efforts have been devoted to the characterization of CML LSCs and to the dissection of the cellâintrinsic and âextrinsic mechanisms sustaining their persistence, in an attempt to find druggable targets enabling LSC eradication. Here we provide an overview and an update on these mechanisms, focusing in particular on the most recent acquisitions. Moreover, we provide a critical appraisal of the clinical relevance and feasibility of LSC targeting in CML
Fertility decline and the emergence of excess female survival in post-reproductive ages in Italy
In Italy, at least in the cohorts born up to the beginning of the twentieth century, women's mortality in post-reproductive ages was influenced by fertility, with large progenies (and, to a lesser extent, childlessness) leading to markedly lower survival chances. This relationship proved strong enough to affect the female-to-male ratio in old age as fertility declined. In this paper, we show that various measures of extra female survival at high ages are closely connected to the fertility transition in Italy, and to its peculiar historical and geographical evolution
Systemic mastocytosis: Molecular landscape and implications for treatment
Over the past decade, we have witnessed significant advances in the molecular characterization of systemic mastocytosis (SM). This has provided important information for a better understanding of the pathogenesis of the disease but has also practically impacted the way we diagnose and manage it. Advances in molecular testing have run in parallel with advances in therapeutic targeting of constitutive active KIT, the major driver of the disease. Therefore, assessing the molecular landscape in each SM patient is essential for diagnosis, prognosis, treatment, and therapeutic efficacy monitoring. This is facilitated by the routine availability of novel technologies like digital PCR and NGS. This review aims to summarize the pathogenesis of the disease, discuss the value of molecular diagnostic testing and how it should be performed, and provide an overview of present and future therapeutic concepts based on fine molecular characterization of SM patients
Kaon physics with the KLOE detector
In this paper we discuss the recent finalized analyses by the KLOE experiment
at DANE: the CPT and Lorentz invariance test with entangled pairs, and the precision measurement of the branching fraction of
the decay . We also present the
status of an ongoing analysis aiming to precisely measure the mass
Spatio-temporal anomalous diffusion in heterogeneous media by NMR
For the first time, the diffusion phase diagram in highly confined colloidal
systems, predicted by Continuous Time Random Walk (CTRW), is experimentally
obtained. Temporal and spatial fractional exponents, and ,
introduced within the framework of CTRW, are simultaneously measured by Pulse
Field Gradient Nuclear Magnetic Resonance technique in samples of micro-beads
dispersed in water. We find that depends on the disorder degree of the
system. Conversely, depends on both bead sizes and magnetic
susceptibility differences within samples. Our findings fully match the CTRW
predictions.Comment: 5 pages, 4 figures, submitted to Phys. Rev. Let
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