Advances in imaging THGEM-based detectors

The thick GEM (THGEM) [1] is an "expanded" GEM, economically produced in the PCB industry by simple drilling and etching in G-10 or other insulating materials (fig. 1). Similar to GEM, its operation is based on electron gas avalanche multiplication in sub-mm holes, resulting in very high gain and fast signals. Due to its large hole size, the THGEM is particularly efficient in transporting the electrons into and from the holes, leading to efficient single-electron detection and effective cascaded operation. The THGEM provides true pixilated radiation localization, ns signals, high gain and high rate capability. For a comprehensive summary of the THGEM properties, the reader is referred to [2, 3]. In this article we present a summary of our recent study on THGEM-based imaging, carried out with a 10x10 cm^2 double-THGEM detector.Comment: 3 pages, 3 figures. Presented at the 10th Pisa Meeting on Advanced Detectors; ELBA-Italy; May 21-27 200

El trasfondo histórico del Sermón de Roš ha-Šaná de Naḥmánides en Acre: el fortalecimiento del núcleo judío en Cataluña

This study identifies literary testimony of the conflict over the nature of the Rosh ha-Shanah prayer in Nahmanides’ Sermon. Acre was in the 13th century home to rival Talmudic academies. In his Sermon for Rosh ha-Shanah, Ramban confronts the founding figures of the Tosafist community in the city. His ongoing controversy with contemporary sages can be read between the lines. Aside from brief segments, the majority of its Halakhic section is specifically aimed at opposing the Tosafists’ rulings, and the way in which material was chosen also highlights its polemical aim. In Ramban’s Novellae, he does not hesitate to argue with Tosafist and Andalusian-Geonic Halakhic rulings. Yet in the Sermon, he prefers citing reservations he had about the former. In the 13th century the intellectual momentum of the Tosafists came to a halt, simultaneous to the flourishing of Ramban’s study hall, and many Talmudic innovations were collected in the Novellae written by Ramban and his disciples. This transition forms an intellectual turning point in Talmud study. The confrontation among the academies in Acre may be viewed as a microcosm of this process.Este estudio analiza el conflicto en torno al carácter de la oración de Roš ha-Šaná en el Sermón de Na?mánides (Rambán). Acre albergaba en el siglo XIII academias talmúdicas rivales, y en su Sermón de Roš ha-Šaná, Rambán confronta a las figuras fundacionales de la congregación tosafista de esa ciudad. Su controversia con sabios coetáneos puede leerse entre líneas y, a excepción de alguna otra referencia a otros asuntos, la mayor parte de su exposición halájica, junto a la manera en la que el material expuesto ha sido elegido, se dedica a combatir las decisiones de aquéllos. En sus Novellae, Rambán no había dudado en discutir tanto las decisiones halájicas tosafistas como las gueónico-andalusíes, pero en el sermón prefiere subrayar sus reservas acerca de aquéllas. De manera simultánea, el impulso de los tosafistas llegaba a su fin, pero las enseñanzas de Rambán florecían, y muchas innovaciones talmúdicas quedaron recogidas en Novellae de Rambán y de sus discípulos. Este trasvase constituye un punto de inflexión en el estudio del Talmud y, por ello, el enfrentamiento entre las academias de Acre puede verse como un microcosmos de ese proceso

Practical knowledge of teaching practice – what counts?

The role of formal and systematic knowledge in socialisation into teaching is in question.There is a rising tendency towards anti-intellectualism in different quarters of the field ofeducational studies coupled with an ever increasing emphasis on tacit understanding andimmersion in practice. Socialisation into professional practice is purported to dependpredominantly on ‘doing’ in situ, and on learning what experienced teachers do and far lesson ‘concept building’. In this paper we argue that the emphasis on immersion in the site ofpractice as the gateway to an understanding of the practice of teaching rests on anoverstated conception of tacit knowledge which misses the crux of professional knowledge.The crux of professional knowledge, we argue, lies in specialised practice languages(Collins, 2011) which constitute criteria of professional practice and enable articulationbetween different reservoirs of knowledge. Emulating what expert practitioners do inpractice is not central to the development of professional knowledge of teaching

A concise review on THGEM detectors

We briefly review the concept and properties of the Thick GEM (THGEM); it is a robust, high-gain gaseous electron multiplier, manufactured economically by standard printed-circuit drilling and etching technology. Its operation and structure resemble that of GEMs but with 5 to 20-fold expanded dimensions. The millimeter-scale hole-size results in good electron transport and in large avalanche-multiplication factors, e.g. reaching 10^7 in double-THGEM cascaded single-photoelectron detectors. The multiplier's material, parameters and shape can be application-tailored; it can operate practically in any counting gas, including noble gases, over a pressure range spanning from 1 mbar to several bars; its operation at cryogenic (LAr) conditions was recently demonstrated. The high gain, sub-millimeter spatial resolution, high counting-rate capability, good timing properties and the possibility of industrial production capability of large-area robust detectors, pave ways towards a broad spectrum of potential applications; some are discussed here in brief.Comment: 8 pages, 11 figures; Invited Review at INSTR08, Novosibirsk, Feb 28-March 5 200

High-throughput functional genomics using CRISPR–Cas9

Forward genetic screens are powerful tools for the discovery and functional annotation of genetic elements. Recently, the RNA-guided CRISPR (clustered regularly interspaced short palindromic repeat)-associated Cas9 nuclease has been combined with genome-scale guide RNA libraries for unbiased, phenotypic screening. In this Review, we describe recent advances using Cas9 for genome-scale screens, including knockout approaches that inactivate genomic loci and strategies that modulate transcriptional activity. We discuss practical aspects of screen design, provide comparisons with RNA interference (RNAi) screening, and outline future applications and challenges.Klarman Family Foundation (Fellowship)Massachusetts Institute of Technology. Simons Center for the Social Brain (Postdoctoral Fellowship)National Human Genome Research Institute (U.S.) (K99-HG008171)National Institute of Mental Health (U.S.) (DP1-MH100706)National Institute of Neurological Disorders and Stroke (U.S.) (R01-NS07312401)National Science Foundation (U.S.) (Waterman Award)W. M. Keck FoundationDamon Runyon Cancer Research FoundationKinship Foundation. Searle Scholars ProgramKlingenstein FoundationVallee FoundationMerkin FoundationSimons FoundationNew York Stem Cell Foundatio

Resourcefulness matters: Student patterns for coping with structural and academic challenges

There is general agreement that there are many structural constraints beyond students’ control which influence the degree of success that students can attain as they learn to participate in academic practice. Less understood are the patterns of students’ experiences of the socio-economic environment of their schooling and university, their views of the enabling and constraining conditions of learning and their perceptions of their agency in overcoming these conditions. The data for our study were collected through a questionnaire survey of 591 Bachelor of Education students across three years of the degree at a South African University. Several patterns of resourcefulness and levels of articulation emerged which reveal complex sets of experiences and strategies as students reflect on adversities and challenges they encountered at school and at university. We argue for an in depth understanding of the nature of student agency which recognises its role in shaping their engagement with material, social, academic and affective challenges