303 research outputs found
Sharpness of the phase transition and exponential decay of the subcritical cluster size for percolation on quasi-transitive graphs
We study homogeneous, independent percolation on general quasi-transitive
graphs. We prove that in the disorder regime where all clusters are finite
almost surely, in fact the expectation of the cluster size is finite. This
extends a well-known theorem by Menshikov and Aizenman & Barsky to all
quasi-transitive graphs. Moreover we deduce that in this disorder regime the
cluster size distribution decays exponentially, extending a result of Aizenman
& Newman. Our results apply to both edge and site percolation, as well as long
range (edge) percolation. The proof is based on a modification of the Aizenman
& Barsky method.Comment: Latex 2e; 25 pages (a4wide); small editorial corrections; one
reference adde
Strict inequalities of critical values in continuum percolation
We consider the supercritical finite-range random connection model where the
points of a homogeneous planar Poisson process are connected with
probability for a given . Performing percolation on the resulting
graph, we show that the critical probabilities for site and bond percolation
satisfy the strict inequality . We also show
that reducing the connection function strictly increases the critical
Poisson intensity. Finally, we deduce that performing a spreading
transformation on (thereby allowing connections over greater distances but
with lower probabilities, leaving average degrees unchanged) {\em strictly}
reduces the critical Poisson intensity. This is of practical relevance,
indicating that in many real networks it is in principle possible to exploit
the presence of spread-out, long range connections, to achieve connectivity at
a strictly lower density value.Comment: 38 pages, 8 figure
Infants hospitalized for Bordetella pertussis infection commonly have respiratory viral coinfections
Epigenetic effects of chromatin remodeling agents on organotypic cultures
Background: Tumor epigenetic defects are of increasing relevance to clinical practice, because they are 'druggable' targets for cancer therapy using chromatin-remodeling agents (CRAs). New evidences highlight the importance of the microenvironment on the epigenome regulation and the need to use culture models able to preserve tissue morphology, to better understand the action of CRAs. Methods & methods: We studied the epigenetic response induced by culturing and CRAs in a preclinical model, preserving ex vivo the original tissue microenvironment and morphology, assessing different epigenetic signatures. Our overall findings suggest that culturing and CRAs cause heterogeneous effects on the genes methylation; CRAs affect the global DNA methylation and can trigger an active DNA demethylation; the culture induces alterations in the histone deacetylase expression. Conclusion: Despite the limited number of cases, these findings can be considered a proof of concept of the possibility to test CRAs epigenetic effects on ex vivo tissues maintained in their native tissue architecture
The composition of the protosolar disk and the formation conditions for comets
Conditions in the protosolar nebula have left their mark in the composition
of cometary volatiles, thought to be some of the most pristine material in the
solar system. Cometary compositions represent the end point of processing that
began in the parent molecular cloud core and continued through the collapse of
that core to form the protosun and the solar nebula, and finally during the
evolution of the solar nebula itself as the cometary bodies were accreting.
Disentangling the effects of the various epochs on the final composition of a
comet is complicated. But comets are not the only source of information about
the solar nebula. Protostellar disks around young stars similar to the protosun
provide a way of investigating the evolution of disks similar to the solar
nebula while they are in the process of evolving to form their own solar
systems. In this way we can learn about the physical and chemical conditions
under which comets formed, and about the types of dynamical processing that
shaped the solar system we see today.
This paper summarizes some recent contributions to our understanding of both
cometary volatiles and the composition, structure and evolution of protostellar
disks.Comment: To appear in Space Science Reviews. The final publication is
available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-
Duration of Untreated Cardiac Arrest and Clinical Relevance of Animal Experiments : The Relationship Between the “No-Flow” Duration and the Severity of Post-Cardiac Arrest Syndrome in a Porcine Model
INTRODUCTION: The study investigated the effect of untreated cardiac arrest (CA), i.e. \u201cno-flow\u201d time, on post-resuscitation myocardial and neurological injury, and survival in a pig model to identify an optimal duration that adequately reflects the most frequent clinical scenario. METHODS:: An established model of myocardial infarction followed by CA and cardiopulmonary resuscitation was used. Twenty-two pigs were subjected to 3 no-flow durations: short (8\u201310?min); intermediate (12\u201313?min); and long (14\u201315?min). Left ventricular ejection fraction (LVEF) was assessed together with thermodilution cardiac output (CO) and high sensitivity cardiac troponin T (hs-cTnT). Neurological impairment was evaluated by neurological scores, serum neuron specific enolase (NSE), and histopathology. RESULTS:: More than 60% of animals survived when the duration of CA was 6413?min, compared to only 20% for a duration 6514?min. Neuronal degeneration and neurological scores showed a trend towards a worse recovery for longer no-flow durations. No animals achieved a good neurological recovery for a no-flow 6514?min, in comparison to a 56% for a duration 6413?min (p?=?0.043). Serum NSE levels significantly correlated with the no-flow duration (r?=?0.892). Longer durations of CA were characterized by lower LVEF and CO compared to shorter durations (p?<?0.05). The longer was the no-flow time, the higher was the number of defibrillations delivered (p?=?0.043). The defibrillations delivered significantly correlated with LVEF and plasma hs-cTnT. CONCLUSIONS:: Longer no-flow durations caused greater post-resuscitation myocardial and neurological dysfunction and reduced survival. An untreated CA of 12\u201313?min may be an optimal choice for a clinically relevant model
Punica granatum L. protects mice against hexavalent chromium-induced genotoxicity
This study investigated the chemoprotective effects of Punica granatum L. (Punicaceae) fruits alcoholic extract (PGE) on mice exposed to hexavalent chromium [Cr(VI)]. Animals were pretreated with PGE (25, 50 or 75 mg/kg/day) for 10 days and subsequently exposed to a sub-lethal dose of Cr(VI) (30 mg/kg). The frequency of micronucleated polychromatic erythrocytes in the bone marrow was investigated and the Cr(VI) levels were measured in the kidneys, liver and plasm. For the survival analysis, mice were previously treated with PGE for 10 days and exposed to a single lethal dose of Cr(VI) (50 mg/kg). Exposure to a sub-lethal dose of Cr(VI) induced a significant increase in the frequency of micronucleated cells. However, the prophylactic treatment with PGE led to a reduction of 44.5% (25 mg/kg), 86.3% (50 mg/kg) and 64.2% (75 mg/kg) in the incidence of micronuclei. In addition, the 50 mg/kg dose of PGE produced a higher chemoprotective effect, since the survival rate was 90%, when compared to that of the non-treated group. In these animals, reduced amounts of chromium were detected in the biological materials, in comparison with the other groups. Taken together, the results demonstrated that PGE exerts a protective effect against Cr(VI)-induced genotoxicity
Desempenho produtivo de porta-enxertos de macieira da série Geneva em solo de replantio
The objective of this work was to identify rootstocks with competitive agronomic potential to substitute those currently used in Southern Brazil for the Galaxy and Fuji Suprema apple scion cultivars cultivated on replanting soils. The experiment was carried out in the municipality of Lebon Regis, in the state of Santa Catarina, Brazil, from the 2009/2010 to the 2014/2015 crop season, in a randomized complete block design, with four replicates. The yield performance of the 'Galaxy' and 'Fuji Suprema' scions grafted on the G.056, G.202, G.213, G.814, G.896, G.969, M.9, and Marubakaido/M.9 rootstocks was evaluated. G.896 and G.814 stood out due to their superior annual and cumulative fruit yields, as well as to their greater yield regularity, although they showed lower ability of dwarfing the scion. The greatest average fruit weight of 'Galaxy' was obtained on G.056 and G.213. For 'Fuji Suprema', G.969 promoted smaller fruits, whereas the other rootstocks did not differ. All the evaluated rootstocks produced less suckers than Marubakaido/M.9 and less burrknots than M.9 and Marubakaido/M.9. In general, on replanting soil conditions, G.202 is promising among dwarfing rootstocks, mainly for 'Fuji Suprema'. G.056, G.814, and G.896 also stand out, and the two first are more specific for 'Fuji Suprema'.O objetivo deste trabalho foi identificar porta-enxertos com potencial agronĂŽmico competitivo para substituir os tradicionalmente usados no Sul do Brasil para as cultivares-copa de macieira Galaxy e Fuji Suprema cultivadas em solo de replantio. O experimento foi conduzido em Lebon Regis, no Estado de Santa Catarina, nas safras de 2009/2010 a 2014/2015, em delineamento experimental de blocos ao acaso, com quatro repetiçÔes. Avaliou-se o desempenho agronĂŽmico das copas 'Galaxy' e 'Fuji Suprema', enxertadas sobre G.056, G.202, G.213, G.814, G.896, G.969, M.9 e Marubakaido/M.9. G.896 e G.814 se destacaram pelas produçÔes de frutos anual e acumulada superiores, bem como pela maior regularidade produtiva, embora tenham apresentado menor capacidade ananizante sobre a copa. As maiores massas mĂ©dias de frutos de 'Galaxy' foram obtidas sobre G.056 e G.213. Para 'Fuji Suprema', G.969 proporcionou frutos menores, enquanto os demais porta-enxertos nĂŁo diferiram entre si. Todos os porta-enxertos avaliados rebrotaram menos que Marubakaido/M.9 e produziram menos âburrknotsâ que M.9 e Marubakaido/M.9. No geral, nas condiçÔes de solo de replantio, G.202 mostra ser promissor entre os porta-enxertos ananizantes, principalmente para 'Fuji Suprema'. Destacam-se tambĂ©m G.056, G.814 e G.896, sendo os dois primeiros mais especĂficos para 'Fuji Suprema'
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