715 research outputs found
Folding and cytoplasm viscoelasticity contribute jointly to chromosome dynamics
The chromosome is a key player of cell physiology, and its dynamics provides
valuable information about its physical organization. In both prokaryotes and
eukaryotes, the short-time motion of chromosomal loci has been described as a
Rouse model in a simple or viscoelastic medium. However, little emphasis has
been put on the role played by the folded organization of chromosomes on the
local dynamics. Clearly, stress-propagation, and thus dynamics, must be
affected by such organization, but a theory allowing to extract such
information from data, e.g.\ of two-point correlations, is lacking. Here, we
describe a theoretical framework able to answer this general polymer dynamics
question, and we provide a general scaling analysis of the stress-propagation
time between two loci at a given arclength distance along the chromosomal
coordinate. The results suggest a precise way to detect folding information
from the dynamical coupling of chromosome segments. Additionally, we realize
this framework in a specific theoretical model of a polymer with variable-range
interactions in a viscoelastic medium characterized by a tunable scaling
exponent, where we derive analytical estimates of the correlation functions.Comment: 14 pages including supplementary material
Seismic vulnerability of churches in Faial and Pico islands, Azores
Earthquakes represent one of the main cause of serious damage and loss of historic and architectural heritage. Interventions to preserve these building should start with a careful knowledge and assessment of their seismic vulnerability, in order to support any needed retrofitting and strengthening measures.
This paper proposes a procedure to register and diagnose of the level of damage on churches after the occurrence of an earthquake, and also to assess the seismic vulnerability of this type of construction. This procedure was applied to sixteen churches in the Azores islands which were hit by the July 9th 1998 earthquake.
Belfries of church towers are elements with a particular seismic vulnerability. For this reason, and based on the Italian methodology proposed by the Linee Guida (2006), it is applied to belfries of two churches from Pico (Azores), a simplified mechanical model for assessment of seismic vulnerability of this type of structures
SOIL ENZYME ACTIVITIES RECOVERY AFTER ORGANIC TREATMENTS OF DEGRADED AREAS WITHIN VINEYARDS
Soil enzymes were used to assess the impact of different treatments applied in four farms, each one with three vineyards as replicates, on soil functionality. 8 enzymes related to C, N, S and P cycling were measured and functional diversity indexes were estimated. Three treatments were compared: compost, green manure and dry mulching with respect to degraded and non-degraded soil. The four vineyards showed different enzymatic patterns and response to treatments. Vineyards with the largest difference between degraded and non-degraded soil have benefited more largely from the treatments. In particular, dry mulching seemed to be more effective than green manure or compost, with the exception of San Disdagio. However, the effect the short term
Protocol for soil functionality assessment in vineyards
Protocols used by Resolve partners during the project, to assess soil functionality on degraded aeras and evaluate soil restoration after applying recovering practices
Protocols for soil functionality assessment in vineyards
The purpose of this guideline is to describe the methods used during ReSolVe project for soil functionality assessment, so they can be implemented in similar studies.
A brief introduction first underlines what are the main functions of soil and why maintaining an optimal soil functionality is particularly of major interest in viticulture.
Then the different protocols selected for ReSolVe project and this guideline are presented according to the following classification:
- Part I: assessment of soil physical and chemical features;
- Part II: assessment of soil biological features (ecosystem service provision and providers);
- Part III: assessment of rhizosphere biological features;
- Part IV: assessment of grapevine quantitative and qualitative indicators reflecting soil functionality.
In each part, global objectives of the monitoring are explained (what is it used for, in which cases…) and the parameters to evaluate are listed with their corresponding methodological sheet.
In these sheets, instructions and information are given about:
- Materials needed to perform the sampling and the measurement
- Sampling procedure
- Analysis procedure
- Possible interpretations and conclusions that can be drawn (value and meaning of the results, indication of reference values when existing, potential limit of the protocol)
- Bibliographic references related to the method described
- Additional helpful information where appropriate (ex: template of sampling sheet
Protocol for soil functionality assessment in vineyards
Protocols used by Resolve partners during the project, to assess soil functionality on degraded aeras and evaluate soil restoration after applying recovering practices
A study of charge collection processes on polycrystalline diamond detectors
Abstract We performed a study of charge collection distance (CCD) on medium to high-quality prototypes of diamond sensors prepared by Chemical Vapor Deposition (CVD). We studied the Charge Collection Efficiency in these materials supposing that it is limited by the presence of a recombination level and a distribution of trap levels centered at 1.7 eV from the band-edge. We also supposed that the exposition to ionizing radiation can make the trap levels ineffective (pumping effect). We have shown that these assumptions are valid by correlating the CCD to the pumping efficiency. Moreover, we have shown that the pumping efficiency is bias-dependent. We have explained our experimental results assuming that trapped carriers generate an electric field inside the diamond bulk
Metodologia para a avaliação da vulnerabilidade sísmica do património religioso: caso de estudo - Faial e Pico, Açores
Os sismos representam uma das grandes causas de danos graves e perda do património histórico e arquitectónico. Qualquer intervenção de reabilitação destes edifícios deve partir de uma cuidada avaliação e análise da sua vulnerabilidade sísmica, de modo a desenvolver, se necessário, estratégias de reforço sísmico adequadas. O principal objectivo do presente artigo é estudar a vulnerabilidade sísmica do património religioso das ilhas do Faial e do Pico, nos Açores. Para tal, numa primeira parte deste trabalho, é proposta uma metodologia para o diagnóstico e registo do grau de dano em igrejas após a ocorrência de um sismo, assim como para a avaliação da vulnerabilidade associada a estas. A partir da análise dos danos observados em dezasseis igrejas afectadas pelo sismo de 9 de Julho de 1998 nos Açores, é elaborada uma base de dados que, para além de reunir as características de cada igreja estudada, apoia o cálculo simplificado do índice de dano, vulnerabilidade e coeficiente de segurança global.
O campanário das torres sineiras é um elemento particularmente vulnerável aos sismos, devido à sua geometria típica. Por um lado, a existência de grandes aberturas a certos níveis produz tipicamente elementos verticais muito esbeltos. Por outro lado, a elevada concentração de massa no topo das torres também contribui para esta vulnerabilidade. Assim, na segunda parte deste trabalho, é aplicada a metodologia italiana, proposta na Linee Guida per la Valutazione e Reduzione del Rischio Sísmico del Patrimônio Culturale, aos campanários de duas igrejas localizadas na ilha do Pico, com base num modelo mecânico simplificado para a avaliação da vulnerabilidade deste tipo de estruturas.
Com o trabalho desenvolvido, pretende-se contribuir para uma sistematização de processos de inspecção e registo de informação relativa a igrejas, com vista a apoiar estratégias de intervenção quer em situações de pós-sismo, quer na mitigação do risco sísmico destas estruturas
Statistical Mechanics of the Chinese Restaurant Process: lack of self-averaging, anomalous finite-size effects and condensation
The Pitman-Yor, or Chinese Restaurant Process, is a stochastic process that
generates distributions following a power-law with exponents lower than two, as
found in a numerous physical, biological, technological and social systems. We
discuss its rich behavior with the tools and viewpoint of statistical
mechanics. We show that this process invariably gives rise to a condensation,
i.e. a distribution dominated by a finite number of classes. We also evaluate
thoroughly the finite-size effects, finding that the lack of stationary state
and self-averaging of the process creates realization-dependent cutoffs and
behavior of the distributions with no equivalent in other statistical
mechanical models.Comment: (5pages, 1 figure
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