Stochastic model for nucleosome sliding in the presence of DNA ligands

Heat-induced mobility of nucleosomes along DNA is an experimentally well-studied phenomenon. A recent experiment shows that the repositioning is modified in the presence of minor-groove binding DNA ligands. We present here a stochastic three-state model for the diffusion of a nucleosome along DNA in the presence of such ligands. It allows us to describe the dynamics and the steady state of such a motion analytically. The analytical results are in excellent agreement with numerical simulations of this stochastic process.With this model, we study the response of a nucleosome to an external force and how it is affected by the presence of ligands.Comment: 10 pages, 8 figures, submitted to Eur. Phys. J.

Marketing de relacionamento

Orientador: Silas Guimaraes MoroMonografia (Especialização) - Universidade Estadual de Ponta Grossa e Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas, Curso de Especialização em Marketing EmpresarialResumo: O objetivo deste trabalho não e dar urn conceito definitivo do Marketing de Relacionamento, mas delinear uma abordagem útil na sua implantação em empresas do mercado, envolvendo a gestão de contas e efetiva prestação de serviços aos clientes, a administração do relacionamento, eficiente utilização da Tecnologia da Informação e uma coerente gestão da força de vendas. A partir de uma análise sobre a importância do marketing, enfatiza o quanto é necessário o seu entendimento para que se supere as dificuldades de sua adoção por empresas tipicamente industriais. Tendo por base a criação de valor e a competitividade da organização, seguem-se neste trabalho, os passos e procedimentos para passar-se de uma administração centrada em produtos para uma administração voltada para o marketing e dai a uma estratégia de negócios centrada nos clientes, estratégia característica do Marketing de Relacionamento. Complementa-se com a gestão da força de vendas que, nos moldes propostos, deve ser gerenciada de modo pratico, sem rebuscamentos, capaz de levá-la aos seus objetivos e aos objetivos da organização. Fatores e sugestão de orientação, motivação e administração eficaz, conforme delineados neste trabalho de monografia podem efetivamente fazer com que o Marketing de Relacionamento seja um facilitador da Iucratividade e da sobrevivência das empresas atuantes no mercado industria

Development and testing of a multidimensional parent reported outcome measure for common presenting complaints of infancy: the UK infant questionnaire.

Objectives: Patient reported outcome measures are recognized as important and valuable tools to monitor patient progress in healthcare. It is fundamental to clinical practice to understand whether the treated patient has improved or not. Despite the highest use of outpatient healthcare among all pediatric age groups, no age-appropriate outcome measures are available for the infant. Therefore, the objective of this study was to develop and test a new infant outcomes instrument for the most common presenting complaints of infancy. Methods: This was a multi-phase study designed to develop a questionnaire using maternal interviews and to test it for reliability and validity for use in well child clinical practice. After collecting the mother’s views, grounded theory and content analysis were used to derive themes and domains for the questionnaire. After achieving face validity, the instrument was evaluated for test-retest reliability, homogeneity and concurrent criterion validity. Subjects comprised a convenience sample of mothers who presented their infants to a university-affiliated chiropractic teaching clinic on the south coast of England. Results: Maternal interviews revealed mothers’ concerns about feeding, sleeping, crying and other aspects of infant activities of daily living resulting in construction of a 12 question instrument. The questionnaire showed excellent test-retest reliability (ICC = 0.96) and good internal consistency (Cronbach’s α = 0.8). In validity testing, ten questions showed positive correlation to a statistically significant degree against their established gold standard references. In all, 294 mother/infant dyads were involved in the research project. Conclusion: The UK Infant Questionnaire is the first parent reported outcome measure for use with the most common complaints of the infant patient based on maternal views. As such, this instrument meets the standard set by the UK National Health Service to involve the parent’s voice in their child’s care, and is therefore innovative in its field. Although further testing is indicated, and we make no claims that this instrument is comprehensive in all aspects of infant well-child care, it may be used by individual clinicians in routine daily practice to gain understanding of clinical progress of individual patients

A preliminary investigation of radar rainfall estimation in the Ardennes region and a first hydrological application for the Ourthe catchment

This paper presents a first assessment of the hydrometeorological potential of a C-band doppler weather radar recently installed by the Royal Meteorological Institute of Belgium near the village of Wideumont in the southern Ardennes region. An analysis of the vertical profile of reflectivity for two contrasting rainfall events confirms the expected differences between stratiform and convective precipitation. The mean areal rainfall over the Ourthe catchment upstream of Tabreux estimated from the Wideumont weather radar using the standard Marshall-Palmer reflectivity-rain rate relation shows biases between +128% and -42% for six selected precipitation events. For two rainfall events the radar-estimated mean areal rainfall is applied to the gauge-calibrated (lumped) HBV-model for the Ourthe upstream of Tabreux, resulting in a significant underestimation with respect to the observed discharge for one event and a closer match for another. A bootstrap analysis using the radar data reveals that the uncertainty in the hourly discharge from the ~1600km2} catchment associated with the sampling uncertainty of the mean areal rainfall estimated from 10 rain gauges evenly spread over the catchment amounts to ±25% for the two events analyzed. This uncertainty is shown to be of the same order of magnitude as that associated with the model variables describing the initial state of the mode

Collision events between RNA polymerases in convergent transcription studied by atomic force microscopy

Atomic force microscopy (AFM) has been used to image, at single molecule resolution, transcription events by Escherichia coli RNA polymerase (RNAP) on a linear DNA template with two convergently aligned λ(pr) promoters. For the first time experimentally, the outcome of collision events during convergent transcription by two identical RNAP has been studied. Measurement of the positions of the RNAP on the DNA, allows distinction of open promoter complexes (OPCs) and elongating complexes (EC) and collided complexes (CC). This discontinuous time-course enables subsequent analysis of collision events where both RNAP remain bound on the DNA. After collision, the elongating RNAP has caused the other (usually stalled) RNAP to back-track along the template. The final positions of the two RNAP indicate that these are collisions between an EC and a stalled EC (SEC) or OPC (previously referred to as sitting-ducks). Interestingly, the distances between the two RNAP show that they are not always at closest approach after ‘collision’ has caused their arrest

A model in vitro system for co-transcriptional splicing

A hallmark of metazoan RNA polymerase II transcripts is the presence of numerous small exons surrounded by large introns. Abundant evidence indicates that splicing to excise introns occurs co-transcriptionally, prior to release of the nascent transcript from RNAP II. Here, we established an efficient model system for co-transcriptional splicing in vitro. In this system, CMV-DNA constructs immobilized on beads generate RNAP II transcripts containing two exons and an intron. Consistent with previous work, our data indicate that elongating nascent transcripts are tethered to RNAP II on the immobilized DNA template. We show that nascent transcripts that reach full length, but are still attached to RNAP II, are efficiently spliced. When the nascent transcript is cleaved within the intron using RNase H, both the 5′ and 3′ cleavage fragments are detected in the bound fraction, where they undergo splicing. Together, our work establishes a system for co-transcriptional splicing in vitro, in which the spliceosome containing the 5′ and 3′ exons are tethered to RNAP II for splicing

T7 RNA Polymerase Functions In Vitro without Clustering

Many nucleic acid polymerases function in clusters known as factories. We investigate whether the RNA polymerase (RNAP) of phage T7 also clusters when active. Using ‘pulldowns’ and fluorescence correlation spectroscopy we find that elongation complexes do not interact in vitro with a Kd<1 µM. Chromosome conformation capture also reveals that genes located 100 kb apart on the E. coli chromosome do not associate more frequently when transcribed by T7 RNAP. We conclude that if clustering does occur in vivo, it must be driven by weak interactions, or mediated by a phage-encoded protein

Alveolar ridge preservation in the esthetic zone

In the esthetic zone, in the case of tooth extraction, the clinician is often confronted with a challenge regarding the optimal decision-making process for providing a solution using dental implants. This is because, after tooth extraction, alveolar bone loss and structural and compositional changes of the covering soft tissues, as well as morphological alterations, can be expected. Ideally, the therapeutic plan starts before tooth extraction and it offers three options: spontaneous healing of the extraction socket; immediate implant placement; and techniques for preserving the alveolar ridge at the site of tooth removal. The decision-making process mainly depends on: (i) the chosen time-point for implant placement and the ability to place a dental implant; (ii) the quality and quantity of soft tissue in the region of the extraction socket; (iii) the remaining height of the buccal bone plate; and (iv) the expected rates of implant survival and success. Based on scientific evidence, three time-periods for alveolar ridge preservation are described in the literature: (i) soft-tissue preservation with 6-8 weeks of healing after tooth extraction (for optimization of the soft tissues); (ii) hard- and soft-tissue preservation with 4-6 months of healing after tooth extraction (for optimization of the hard and soft tissues); and (iii) hard-tissue preservation with > 6 months of healing after tooth extraction (for optimization of the hard tissues)