Changes in murine anorectum signaling across the life course

Background: Increasing age is associated with an increase in the incidence of chronic constipation and fecal impaction. The contribution of the natural aging process to these conditions is not fully understood. This study examined the effects of increasing age on the function of the murine anorectum.Methods: The effects of increasing age on cholinergic, nitrergic, and purinergic signaling pathways in the murine anorectum were examined using classical organ bath assays to examine tissue function and electrochemical sensing to determine age‐related changes in nitric oxide and acetylcholine release.Key Results: Nitrergic relaxation increased between 3 and 6 months, peaked at 12 months and declined in the 18 and 24 months groups. These changes were in part explained by an age‐related decrease in nitric oxide (NO) release. Cholinergic signaling was maintained with age by an increase in acetylcholine (ACh) release and a compensatory decrease in cholinesterase activity. Age‐related changes in purinergic relaxation were qualitatively similar to nitrergic relaxation although the relaxations were much smaller. Increasing age did not alter the response of the anorectum smooth muscle to exogenously applied ACh, ATP, sodium nitroprusside or KCl. Similarly, there was no change in basal tension developed by the anorectum.Conclusions and Inferences: The decrease in nitrergic signaling with increasing age may contribute to the age‐related fecal impaction and constipation previously described in this model by partially obstructing defecation

Do sixth-grade writers need process strategies?

Background: Strategy-focussed writing instruction trains students both to set explicit product goals and to adopt specific procedural strategies, particularly for planning text. A number of studies have demonstrated that strategy-focussed writing instruction is effective in developing writing performance. Aim: The present study aimed to determine whether teaching process strategies provides additional benefit over teaching students to set product goals. Sample: 94 typically developing Spanish sixth-grade (upper primary) students. Method: Students received 10 hours of instruction in one of three conditions: Strategy-focussed training in setting product goals and in writing procedures (planning and revision; Product-and-Process), strategy-focussed training in setting product goals (Product-Only), and product-focussed instruction (Control). Students' writing performance was assessed before, during, and after intervention with process measures based on probed self-report and holistic and text-analytic measures of text quality. Results: Training that included process instruction was successful in changing students' writing processes, with no equivalent process changes in the Product-Only or control conditions. Both Process-and-Product and Product-Only conditions resulted in substantial improvements in the quality of students' texts relative to controls, but with no evidence of benefits of process instruction over those provided by the Product-Only condition. Teaching process substantially increased time-on-task. Conclusions: Our findings confirm the value of strategy-focussed writing instruction, but question the value of training specific process strategies

MAGIC sensitivity to millisecond-duration optical pulses

The MAGIC telescopes are a system of two Imaging Atmospheric Cherenkov Telescopes (IACTs) designed to observe very high energy (VHE) gamma rays above ~50 GeV. However, as IACTs are sensitive to Cherenkov light in the UV/blue and use photo-detectors with a time response well below the ms scale, MAGIC is also able to perform simultaneous optical observations. Through an alternative system installed in the central PMT of MAGIC II camera, the so-called central pixel, MAGIC is sensitive to short (1ms - 1s) optical pulses. Periodic signals from the Crab pulsar are regularly monitored. Here we report for the first time the experimental determination of the sensitivity of the central pixel to isolated 1-10 ms long optical pulses. The result of this study is relevant for searches of fast transients such as Fast Radio Bursts (FRBs).Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Bexco, Busan, Korea (arXiv:1708.05153

Pasado, presente y futuro de la Realidad Virtual: análisis a partir de las variables tecnológica y de definición del término

Developments in Virtual Reality (VR) technology are currently arousing great scientific interest because in just a few years, VR has found its niche not only in the specialised public, but also in society in general and in different contexts, thanks to its many uses in different contexts and the decreasing price of VR viewing devices. To many, this technology may appear to be a novelty of the 21st century, but its origins go back several decades. Taking into account these aspects, this article aims to analyse the past and present of VR from two perspectives: one focused on its technological development and one on its conceptual evolution. This historical overview, in turn, will allow us to address the future applications of VR in different disciplines. The study provides the reader with an indepth analysis of VR that will contribute to the understanding of this technology and its uses.Hoy en día todo lo relacionado con la Realidad Virtual (RV) despierta un gran interés científico. Tal es así que en pocos años ha conseguido hacerse un hueco no solo entre el público especializado, sino también entre la sociedad en general, ya que, sus aplicaciones son muchas y en diferentes contextos. Este hecho ha sido posible en gran medida gracias al imparable desarrollo tecnológico y al abaratamiento de los dispositivos de visualización. Parecería, por tanto, que esta tecnología es una novedad del sigo XXI, pero lo cierto es que sus orígenes se remontan varias décadas en el pasado. Teniendo en cuenta estos aspectos, este artículo tiene como objetivo analizar el pasado y el presente de la RV desde una doble perspectiva: la que tiene que ver, por una parte, con su desarrollo tecnológico y, por otra, con la definición del término. Dicho recorrido histórico, a su vez, permitirá abordar las perspectivas de futuro de la RV desde el punto de vista de sus aplicaciones dentro de diferentes disciplinas. Todo ello dotará al lector de una visión en profundidad acerca de la tecnología de la RV que servirá para comprender

Techno-economic analysis of biofuel production via bio-oil zeolite upgrading: An evaluation of two catalyst regeneration systems

Biofuels have been identified as a mid-term greenhouse gas (GHG) emissions abatement solution for decarbonising the transport sector. This study examines the techno-economic analysis of biofuel production via biomass fast pyrolysis and subsequent bio-oil upgrading via zeolite cracking. The aim of this study is to compare the techno-economic feasibility of two conceptual catalyst regeneration configurations for the zeolite cracking process: (i) a two-stage regenerator operating sequentially in partial and complete combustion modes (P-2RG) and (ii) a single stage regenerator operating in complete combustion mode coupled with a catalyst cooler (P-1RGC). The designs were implemented in Aspen Plus® based on a hypothetical 72 t/day pine wood fast pyrolysis and zeolite cracking plant and compared in terms of energy efficiency and profitability. The energy efficiencies of P-2RG and P-1RGC were estimated at 54% and 52%, respectively with corresponding minimum fuel selling prices (MFSPs) of £7.48/GGE and £7.20/GGE. Sensitivity analysis revealed that the MFSPs of both designs are mainly sensitive to variations in fuel yield, operating cost and income tax. Furthermore, uncertainty analysis indicated that the likely range of the MFSPs of P-1RGC (£5.81/GGE − £11.63/GGE) at 95% probability was more economically favourable compared with P-2RG, along with a penalty of 2% reduction in energy efficiency. The results provide evidence to support the economic viability of biofuel production via zeolite cracking of pyrolysis-derived bio-oil

Effects of direct instruction and strategy modelling on upper-primary students' writing development

Strategy-focused instruction is one of the most effective approaches to improve writing skills. It aims to teach developing writers strategies that give them executive control over their writing processes. Programs under this kind of instruction tend to have multiple components that include direct instruction, modeling and scaffolded practice. This multi-component nature has two drawbacks: it makes implementation challenging due to the amount of time and training required to perform each stage, and it is difficult to determine the underlying mechanisms that contribute to its effectiveness. To unpack why strategy-focused instruction is effective, we explored the specific effects of two key components: direct teaching of writing strategies and modeling of strategy use. Six classes (133 students) of upper-primary education were randomly assigned to one of the two experimental conditions, in which students received instruction aimed at developing effective strategies for planning and drafting, or control group with no strategy instruction: Direct Instruction (N = 46), Modeling (N = 45), and Control (N = 42). Writing performance was assessed before the intervention and immediately after the intervention with two tasks, one collaborative and the other one individual to explore whether differential effects resulted from students writing alone or in pairs. Writing performance was assessed through reader-based and text-based measures of text quality. Results at post-test showed similar improvement in both intervention conditions, relatively to controls, in all measures and in both the collaborative and the individual task. No statistically significant differences were observed between experimental conditions. These findings suggest that both components, direct teaching and modeling, are equally effective in improving writing skills in upper primary students, and these effects are present even after a short training

Optimal dose calibration in radiotherapy

In this paper, the tools provided by the theory of Optimal Experimental Design are applied to a nonlinear calibration model. This is motivated by the need of estimating radiation doses using radiochromic films for radiotherapy purposes. The calibration model is in this case nonlinear and the explanatory variable cannot be worked out explicitly from the model. In this case an experimental design has to be found on the dependent variable. For that, the inverse function theorem will be used to obtain an information matrix to be optimized. Optimal designs on the response variable are computed from two different perspectives, first for fitting the model and estimating each of the parameters and then for predicting the proper dose. While the first is a common point of view in a general context of the Optimal Experimental Design, the latter is actually the main objective of the calibration problem for the practitioners and algorithms for computing these optimal designs are also provided. The optimal designs obtained have just three different points in their support, but practitioners usually demand for more support points. Thus, a methodology for computing space-filling designs is also provided when the support points are forced to follow some mathematical rule, such as arithmetic or geometric sequences. Cross efficiencies of all these designs are computed in order to show their ability for different goals

Evaluating effects of different forms of revision instruction in upper-primary students

p. 1741-1767This study aimed to establish (a) whether teaching students revision skills provides beneft over and above teaching strategies for setting explicit goals for the communicative efect of their text, and (b) whether teaching students to adopt specifc revision strategies provides benefts over revision instruction that focusses on increasing students’ awareness of audience needs. Six classes of Spanish sixth-grade students (N=107, 11–12 years) were randomly assigned to one of three conditions. In all three conditions students were taught to set communicative goals. Students in the Strategy Focused condition were then taught a 6-step revision strategy. Students in the Reader Focused condition observed a reader trying to comprehend a text and suggesting ways in which it might be improved. Students in a control condition continued with goal-setting practice. Students’ writing performance was assessed through composition and revision tasks before and immediately after intervention, 2 months post-intervention, and for transfer to an untaught genre. Writing performance and revision skills improved more in the two revision-instruction conditions than for students in the control condition. The improvements were large, persistent and transferred to a diferent type of text. We found no statistically signifcant diferences between the two revision conditions. Findings suggest that specifc revision instruction benefts sixth-grade students’ writing performance and revision skills, but that strategy-focused and reader-focused approaches are similarly efectiveS