1,674 research outputs found

    Subventricular zone stem cells are heterogeneous with respect to their embryonic origins and neurogenic fates in the adult olfactory bulb

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    Wedetermined the embryonic origins of adult forebrain subventricular zone (SVZ) stem cells by Cre-lox fate mapping in transgenic mice. We found that all parts of the telencephalic neuroepithelium, including the medial ganglionic eminence and lateral ganglionic eminence (LGE) and the cerebral cortex, contribute multipotent, self-renewing stem cells to the adult SVZ. Descendants of the embryonic LGE and cortex settle in ventral and dorsal aspects of the dorsolateral SVZ, respectively. Both populations contribute new (5-bromo-2(')-deoxyuridine- labeled) tyrosine hydroxylase- and calretinin-positive interneurons to the adult olfactory bulb. However, calbindin-positive interneurons in the olfactory glomeruli were generated exclusively by LGE- derived stem cells. Thus, different SVZ stem cells have different embryonic origins, colonize different parts of the SVZ, and generate different neuronal progeny, suggesting that some aspects of embryonic patterning are preserved in the adult SVZ. This could have important implications for the design of endogenous stem cell-based therapies in the future

    Orthogonality catastrophe as a consequence of qubit embedding in an ultra-cold Fermi gas

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    We investigate the behaviour of a single qubit coupled to a low-dimensional, ultra-cold Fermi gas. The scattering between the system and the fermions leads to the loss of any coherence in the initial state of the qubit and we show that the exact dynamics of this process is strongly influenced by the effect of the orthogonality catastrophe within the gas. We highlight the relationship between the Loschmidt echo and the retarded Green's function - typically used to formulate the dynamical theory of the catastrophe - and demonstrate that the effect can be triggered and characterized via local operations on the qubit. We demonstrate how the expected broadening of the spectral function can be observed using Ramsey interferometry on the qubit.Comment: 4 and a bit pages, 3 figures. Updated versio

    Transformative learning through university and prison partnerships: reflections from ‘Learning Together’ pedagogical practice

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    This paper critically discusses two London-based “Learning Together” prison university partnerships—Middlesex University with Her Majesty’s Prison (HMP) Wandsworth and London South Bank University (LSBU) with HMP Pentonville. The paper documents how students experienced the shared classroom learning approach designed on principles of “transformative pedagogy”, and how students interpret their personal development and the knowledge and skills gained as a result. We share the steps taken to bring the learning together pedagogical philosophy to life and use evidence from module evaluation findings and critical reflections to demonstrate the transformations that happen. We interpret our findings through the lens of a transformative ripples model. In addition to exploring personal transformation, the wider transformations that occur within the public institutions at the centre of these collaborations—the prisons and the universities —are discussed. We argue that for prison and university partnerships to be truly effective, they must embed transformative pedagogic practices at their heart, ensuring the “how”we teach is as important, and deliberately considered, as the “what” we teach

    X-ray production in low energy proton stopping

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    The X-ray yields of stopping protons in an iron-nickel-cobalt alloy are calculated for use in predicting radiation damage in encased electronic devices

    Notes on Papyri: P.Oxy. 18.2195

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    Center for Applied Radiation Research (CARR)

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    Prairie View A&M University (PVAMU) Center for Applied Radiation Research (CARR) was established in 1995 to address the tasks, missions and technological needs of NASA. CARR is built on a tradition of radiation research at Prairie View A&M started in 1984 with NASA funding. This continuing program has lead to: (1) A more fundamental and practical understanding of radiation effects on electronics and materials; (2) A dialog between space, military and commercial electronics manufacturers; (3) Innovative electronic circuit designs; (4) Development of state-of-the-art research facilities at PVAMU; (5) Expanded faculty and staff to mentor student research; and (6) Most importantly, increased flow in the pipeline leading to expanded participation of African-Americans and other minorities in science and technological fields of interest to NASA

    Nuclear fragmentation studies for microelectronic application

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    A formalism for target fragment transport is presented with application to energy loss spectra in thin silicon devices. Predicted results are compared to experiments with the surface barrier detectors of McNulty et al. The intranuclear cascade nuclear reaction model does not predict the McNulty experimental data for the highest energy events. A semiempirical nuclear cross section gives an adequate explanation of McNulty's experiments. Application of the formalism to specific electronic devices is discussed

    Resilience: distinct construct or conglomerate of existing traits?

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    Since its inception in mainstream scientific psychology, resilience has emerged as a popular, yet controversial, construct. As evidenced in the target article, this controversy can be attributed, at least in part, to current conceptual and methodological difficulties hampering understanding of the construct. Chief among these concerns is the discriminant validity of resilience with respect to conceptually similar individual differences constructs, such as hardiness, mental toughness, adaptability, and even the five-factor personality dimensions. Advances in research on resilience, and ultimately the utility of the construct in applied settings, hinge on its distinction from related concepts. In this commentary, we extend Britt, Shen, Sinclair, Grossman, and Klieger’s (2016) brief discussion of dimensional redundancy, maintaining that the demonstration of discriminant validity is a necessary first step toward the conceptual clarification of resilience.We first provide an overview of the “jangle” fallacy, which serves as a basis for discussing the importance of construct discrimination to construct validity. We thereafter briefly review existing literature on the distinction, or lack thereof, between resilience and conceptually analogous constructs. Our commentary closes with a reevaluation of the potential contribution of resilience to organizational science

    Effects of cosmic rays on single event upsets

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    Assistance was provided to the Brookhaven Single Event Upset (SEU) Test Facility. Computer codes were developed for fragmentation and secondary radiation affecting Very Large Scale Integration (VLSI) in space. A computer controlled CV (HP4192) test was developed for Terman analysis. Also developed were high speed parametric tests which are independent of operator judgment and a charge pumping technique for measurement of D(sub it) (E). The X-ray secondary effects, and parametric degradation as a function of dose rate were simulated. The SPICE simulation of static RAMs with various resistor filters was tested
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