Evolution and management of humid landscapes in Northern Dauphiné (Rhône valley, France): contribution of charcoal and wood studies

National audienceEvolution and management of humid landscapes in Northern Dauphiné (Rhône valley, France): contribution of charcoal and wood studie

On the Development of a Computer-Based Tool for Formative Student Assessment: Epistemological, Methodological, and Practical Issues

Formative assessments in schools have the potential to improve students’ learning outcomes and self-regulation skills; they make learning visible and provide evidence-based guidelines for setting up and pursuing individual learning goals. With the recent introduction of the computer-based formative assessment systems for the educational contexts, there is much hope that such systems will provide teachers and students with valuable information to guide the learning process without taking much time from teaching and learning to spend on generating, evaluating and interpreting assessments. In this paper, we combine the theoretical and applied perspectives by addressing (a) the epistemological aspects of the formative assessment, with an emphasis on data collection, model building, and interpretation; (b) the methodological challenges of providing feedback in the context of instruction in the classroom; and (c) practical requirements for and related challenges of setting up and delivering the assessment system to a large number of students. In the epistemological section, we develop and explicate the interpretive argument of formative assessment and discuss the challenges of obtaining data with high validity. From the methodological perspective, we argue that computer-based formative assessment systems are generally superior to the traditional methods of providing feedback in the classroom, as they better allow supporting inferences of the interpretive argument. In the section on practical requirements, we first introduce an existing computer-based formative assessment system, as a case in point, for discussing related practical challenges. Topics covered in this section comprise the specifications of assessment content, the calibration and maintenance of the item bank, challenges concerning teachers’ and students’ assessment literacy, as well as ethical and data-protection requirements. We conclude with an outlook on possible future directions for computer-based formative assessment systems and the field in general

Improvement of Measurement Efficiency in Multistage Tests by Targeted Assignment

A good match between item difficulty and student ability ensures efficient measurement and prevents students from becoming discouraged or bored by test items that are too easy or too difficult. Targeted test designs consider ability-related background variables to assign students to matching test forms. However, these designs do not consider that students might significantly differ in ability within the resulting groups. In contrast, multistage test designs consider students' performance during test taking to route them to the most informative modules. Yet, multistage test designs usually include one starting module of moderate difficulty in the first stage, which does not account for differences in ability. In this paper, we investigated whether measurement efficiency can be improved by targeted multistage test designs that consider ability-related background information for a targeted assignment at the beginning of the test and performance during test taking for selecting matching test modules. By means of simulations, we compared the efficiency of the traditional targeted test design, the multistage test (MST) design, and the targeted multistage test (TMST) design for estimating student ability. Furthermore, we analyzed the extent to which the efficiency of the different designs depends on the correlation between the ability-related background variable and the true ability, students' ability level and their categorization into an ability group, and the length of the starting module. The results indicated that TMST designs were generally more efficient for estimating student ability than targeted test designs and MST designs, especially if the ability-related background variable correlated high with and, thus, was a good indicator of, students' true ability. Furthermore, TMST designs were particularly efficient in estimating abilities for low- and high-ability students within a given population. Finally, very long starting modules resulted in less efficient estimation of low and high abilities than shorter starting modules. However, this finding was more prominent for MST than for TMST designs. In conclusion, TMST designs are recommended for assessing students from a wide ability distribution if a reliable ability-related background variable is available

Enhanced neuroinflammation and pain hypersensitivity after peripheral nerve injury in rats expressing mutated superoxide dismutase 1

<p>Abstract</p> <p>Background</p> <p>Neuroinflammation and nitroxidative stress are implicated in the pathophysiology of neuropathic pain. In view of both processes, microglial and astroglial activation in the spinal dorsal horn play a predominant role. The present study investigated the severity of neuropathic pain and the degree of glial activation in an inflammatory- and nitroxidative-prone animal model.</p> <p>Methods</p> <p>Transgenic rats expressing mutated superoxide dismutase 1 (hSOD1^G93A) are classically used as a model for amyotrophic lateral sclerosis (ALS). Because of the associated inflammatory- and nitroxidative-prone properties, this model was used to study thermal and mechanical hypersensitivity following partial sciatic nerve ligation (PSNL). Next to pain hypersensitivity assessment, microglial and astroglial activation states were moreover characterized, as well as inflammatory marker gene expression and the glutamate clearance system.</p> <p>Results</p> <p>PSNL induced thermal and mechanical hypersensitivity in both wild-type (WT) and transgenic rats. However, the degree of thermal hypersensitivity was found to be exacerbated in transgenic rats while mechanical hypersensitivity was only slightly and not significantly increased. Microglial Iba1 expression was found to be increased in the ipsilateral dorsal horn of the lumbar spinal cord after PSNL but such Iba1 up-regulation was enhanced in transgenic rats as compared WT rats, both at 3 days and at 21 days after injury. Moreover, mRNA levels of Nox2, a key enzyme in microglial activation, but also of pro-inflammatory markers (IL-1β and TLR4) were not modified in WT ligated rats at 21 days after PSNL as compared to WT sham group while transgenic ligated rats showed up-regulated gene expression of these 3 targets. On the other hand, the PSNL-induced increase in GFAP immunoreactivity spreading that was evidenced in WT rats was unexpectedly found to be attenuated in transgenic ligated rats. Finally, GLT-1 gene expression and uptake activity were shown to be similar between WT sham and WT ligated rats at 21 days after injury, while both parameters were significantly increased in the ipsilateral dorsal region of the lumbar spinal cord of hSOD1^G93Arats.</p> <p>Conclusions</p> <p>Taken together, our findings show that exacerbated microglial activation and subsequent inflammatory and nitroxidative processes are associated with the severity of neuropathic pain symptoms.</p

20 GHz instantaneous bandwidth RF spectrum analyzer with high time-resolution

International audienceWe report on the experimental demonstration of a multi-gigahertz bandwidth RF spectrum analyzer exhibiting a resolution below 20 MHz, based on spectral hole burning in a rare-earth ion-doped crystal. To be compatible with demanding real-time spectrum monitoring applications, our demonstrator is designed to reach a high time resolution. For this purpose, we implemented the so-called "rainbow" architecture in which the spectral components of the incoming signal are angularly separated by the crystal, and are then acquired with a pixelated photodetector. The Tm 3+ :YAG crystal is programmed with a semiconductor DFB laser which frequency scan is servo-controlled and synchronized with the angular scan of a resonant galvanometric mirror, while a high-speed camera is used to acquire the spectra. In the perspective of future implementation within a system, the crystal is cooled below 4 K with a closed-cycle cryostat. With this setup, we have been able to monitor and record the spectrum of complex microwave signals over an instantaneous bandwidth above 20 GHz, with a time resolution below 100 µs, 400 resolvable frequency components and a probability of intercept of 100 %

Host Galaxies of Gamma-Ray Bursts and their Cosmological Evolution

We use numerical simulations of large scale structure formation to explore the cosmological properties of Gamma-Ray Burst (GRB) host galaxies. Among the different sub-populations found in the simulations, we identify the host galaxies as the most efficient star-forming objects, i.e. galaxies with high specific star formation rates. We find that the host candidates are low-mass, young galaxies with low to moderate star formation rate. These properties are consistent with those observed in GRB hosts, most of which are sub-luminous, blue galaxies. Assuming that host candidates are galaxies with high star formation rates would have given conclusions inconsistent with the observations. The specific star formation rate, given a galaxy mass, is shown to increase as the redshift increases. The low mass of the putative hosts makes them difficult to detect with present day telescopes and the probability density function of the specific star formation rate is predicted to change depending on whether or not these galaxies are observed.Comment: 11 pages, 10 figures. Accepted for publication in MNRA

The gut-lung axis in the CFTR modulator era

The advent of CFTR modulators represents a turning point in the history of cystic fibrosis (CF) management, changing profoundly the disease’s clinical course by improving mucosal hydration. Assessing changes in airway and digestive tract microbiomes is of great interest to better understand the mechanisms and to predict disease evolution. Bacterial and fungal dysbiosis have been well documented in patients with CF; yet the impact of CFTR modulators on microbial communities has only been partially deciphered to date. In this review, we aim to summarize the current state of knowledge regarding the impact of CFTR modulators on both pulmonary and digestive microbiomes. Our analysis also covers the inter-organ connections between lung and gut communities, in order to highlight the gut-lung axis involvement in CF pathophysiology and its evolution in the era of novel modulators therapies