1,142 research outputs found
Control of expression of the RNases J1 and J2 in bacillus subtilis
In Bacillus subtilis, the dual activity 5' exo- and endoribonucleases J1 and J2 are important players in mRNA and stable RNA maturation and degradation. Recent work has improved our understanding of their structure and mechanism of action and identified numerous RNA substrates. However, almost nothing is known about the expression of these enzymes. Here, we have identified the transcriptional and translational signals that control the expression of the rnjA (RNase J1) and rnjB (RNase J2) genes. While the rnjB gene is transcribed constitutively from a sigma A promoter, optimal expression of RNase J1 requires cotranscription and cotranslation with the upstream ykzG gene, encoding a protein of unknown function. In the absence of coupled translation, RNase J1 expression is decreased more than 5-fold. Transcription of the ykzG operon initiates at a sigma A promoter with a noncanonical -35 box that is required for optimal transcription. Biosynthesis of RNase J1 is autocontrolled within a small range (1.4-fold) and also slightly stimulated (1.4-fold) in the absence of RNase J2. These controls are weak but might be useful to maintain the overall RNase J level and possibly also equimolar amounts of the two nucleases in the cell that primarily act as a heterodimer in vivo. © 2014, American Society for Microbiology
Addressing Interprofessional Competence in Interpretation of Electronic Fetal Monitor Tracings
Interpretation of electronic fetal monitor (EFM) tracings is a critical clinical practice skill nurses and physicians perform during the intrapartum stage of pregnancy. However, if performed inaccurately can potentially jeopardize the well-being of the neonate. This risk is present because if concerning EFM tracings are not interpreted accurately, preventative care interventions to promote the well-being of the unborn child do not occur. The project was initiated by completing a scoping literature review on the methods for training and evaluating EFM interpretation competence, which revealed current EFM interpretation training and evaluation methods are lacking. A concept analysis defined nurse competence in diagnostic healthcare technologies. The analysis included examining surrogate terms, related concepts, attributes, antecedents, and consequences. This dissertation evaluated the feasibility and effectiveness of a Simulation-Based Mastery Learning intervention on clinical interprofessional team membersâ EFM interpretation competence and self-efficacy compared to clinical experience alone. In addition, it determined how participantsâ characteristics affect baseline EFM interpretation scores. The study was a randomized longitudinal design with participants recruited from a convenience sample of interprofessional healthcare team members from a large research hospital in the southeastern United States. Randomization procedures placed recruited participants into either an intervention or clinical experience alone group, with competence evaluations for both groups occurring at baseline, immediately post-intervention, and three months post-intervention. Once completed, add results and conclusion here
Thermal phase diagrams of columnar liquid crystals
In order to understand the possible sequence of transitions from the
disordered columnar phase to the helical phase in hexa(hexylthio)triphenylene
(HHTT), we study a three-dimensional planar model with octupolar interactions
inscribed on a triangular lattice of columns. We obtain thermal phase diagrams
using a mean-field approximation and Monte Carlo simulations. These two
approaches give similar results, namely, in the quasi one-dimensional regime,
as the temperature is lowered, the columns order with a linear polarization,
whereas helical phases develop at lower temperatures. The helicity patterns of
the helical phases are determined by the exact nature of the frustration in the
system, itself related to the octupolar nature of the molecules.Comment: 12 pages, 9 figures, ReVTe
Strategy to design the sea-level monitoring networks for small tsunamigenic oceanic basins: the Western Mediterranean case
The 26 December 2004 Indian Ocean tsunami triggered a number of international and national initiatives aimed at establishing modern, reliable and robust tsunami warning systems. In addition to the seismic network for initial warning, the main component of the monitoring system is the sea level network. Networks of coastal tide gages and tsunameters are implemented to detect the tsunami after the occurrence of a large earthquake, to confirm or refute the tsunami occurrence. Large oceans tsunami monitoring currently in place in the Pacific and in implementation in the Indian Ocean will be able to detect tsunamis in 1 h. But due to the very short time of waves propagation, in general less than 1 h, a tsunami monitoring system in a smaller basin requires a denser network located close to the seismic zones. A methodology is proposed based on the modeling of tsunami travel time and waveform, and on the estimation of the delay of transmission to design the location and the spacing of the stations. In the case of Western Mediterranean, we demonstrate that a network of around 17 coastal tide gages and 13 tsunameters located at 50 km along the shore is required to detect and measure nearly all tsunamis generated on the Northern coasts of Africa
Evaluation of far-field tsunami hazard in French Polynesia based on historical data and numerical simulations
International audienceThe first tsunami hazard map of French Polynesia is presented here on the basis of historical data, and numerical simulations. French Polynesia, because of its central position in the most tsunami prone ocean, the Pacific, is strongly exposed to far-field tsunamis. As no previous study on the area had been conducted, we compiled catalogues of all the historical observations (14 events), and tide gauges records (69 marigrams). The catalogues emphasise the higher hazard associated to the Marquesas archipelago, but also the deficiency of robust data in most other parts of French Polynesia. The recourse to numerical simulations allowed us to complement the existing records, and to test tsunami scenarii over different bathymetry and topography configurations, representative of the diversity of islands in French Polynesia. The tsunami hazard map assigns a high exposure level to the Marquesas and the island of Rurutu. Other islands of the Austral, and the Gambier archipelago have a elevated level of exposure, as well as three islands of Society: Tahiti, Moorea, and Huahine. All other islands of French Polynesia are considered as moderately exposed
ProlégomÚnes à toute appréciation critique de CANDIDE
This text describes the CANDIDE model from three critical points of view. First, it presents the structure of the model with the aid of a table of "supersectors" and a flow chart. The discussion of the linkages between these supersectors brings out the general equilibrium character of the model.The center section of the paper deals with the theoretical foundations of the behavioural equations. A statement of the equation specification in each sector of the model is followed by a brief evaluation. The authors confess to an eclectic attitude and stress the practical difficulties of making stylized theories bring order in variegated facts. Exogenous influences on the model are discussed as well.The same eclectic approach is evident in the third part of the text which treats of estimation and validation. A variety of tests and checksâsome novel ones includedâare applied in the process of developing the model. The authors conclude with the observation that recent tumultuous developments in the economy raise fundamental questions about the validity and usefulness of models like CANDIDE
Propagation on networks: an exact alternative perspective
By generating the specifics of a network structure only when needed
(on-the-fly), we derive a simple stochastic process that exactly models the
time evolution of susceptible-infectious dynamics on finite-size networks. The
small number of dynamical variables of this birth-death Markov process greatly
simplifies analytical calculations. We show how a dual analytical description,
treating large scale epidemics with a Gaussian approximations and small
outbreaks with a branching process, provides an accurate approximation of the
distribution even for rather small networks. The approach also offers important
computational advantages and generalizes to a vast class of systems.Comment: 8 pages, 4 figure
Urinary excretion of dithiocarbamates and selfreported Cruciferous vegetable intake: application of the âmethod of triadsâ to a foodspecific biomarker
Objective: Greater intake of Cruciferous vegetables (e.g. broccoli) may prevent cancer at several sites. Urinary excretion of isothiocyanate conjugates (dithiocarbamates, DTC) provides a specific biomarker of Cruciferous vegetable consumption suitable for epidemiological investigations. However, no gold-standard referent is available for evaluating urinary DTC levels as an estimator of Cruciferous vegetable consumption. We compared urinary DTC levels to intake as measured by two selfreported dietary assessment techniques. Design: Cruciferous vegetable consumption was measured before and after a behavioural dietary intervention using multiple 24-hour recalls (24HR), a foodcounting questionnaire (VFQ) and urinary DTC excretion levels. Analysis included a structural equation approach (Method of Triads) combining these three assessment techniques to estimate the relationship between DTC level and the study populationâs âtrueâ Cruciferous vegetable intake. Setting: The intervention curriculum assisted participants in consuming about 2 servings per day for a 6-week period. Participants attended four classes emphasising problem-solving skills, dietary counselling and vegetable preparation skills. There were no dietary restrictions. Subjects: Thirty-three healthy, free-living, post-menopausal women. Results: Although few participants reported Cruciferae consumption prior to the intervention, 30 participants reported Cruciferae consumption after the intervention (Post-intervention). Urinary DTC levels were correlated with estimated intake derived from either the 24HR (r ÂŒ 0:57; 95% confidence interval (95% CI) 0.28, 0.76) or VFQ (r ÂŒ 0:49; 95% CI 0.17, 0.71). The validity coefficient (Method of Triads) between urinary DTC excretion and an index of true Cruciferous intake was stronger than the Pearson correlation (rv ÂŒ 0:65; 95% CI 0.35, 0.90), and comparable to estimates derived from the 24HR (rv ÂŒ 0:82; 95% CI 0.65, 1.00) or VFQ (rv ÂŒ 0:76; 95% CI 0.47, 0.92) method. These associations were not affected by adjustment for body mass index, energy intake, or social approval or desirability response sets. Conclusions: Food-frequency questionnaires (FFQ) suitable for large epidemiological studies may not be designed to measure all Cruciferae, and cannot capture exposure to phytochemicals derived from those vegetables. Urinary DTC measurement was significantly correlated with Cruciferae intake derived from two dietary assessment approaches, and urinaryDTC levels could supplement traditional FFQdata by providing an index of recent Cruciferous vegetable intake not susceptible to reporting biases
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