9,998 research outputs found

    Supporting Higher Education—Hospital Transition through Blended Learning

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    The purpose of this paper is to present two exploratory studies that have a potential for identifying research-based blended learning tools for CBME. The studies focus on the development of a group of medical students’ professional image (in Genova and Rome) during their hospital internship. The paper addresses three related questions: 1. How does their professional representation change in the transition from university to hospital? 2. Which competences emerge from the students’ reports? 3. Which competences are still under represented

    Fluid-solid transition in unsteady, homogeneous, granular shear flows

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    Discrete element numerical simulations of unsteady, homogeneous shear flows have been performed by instantly applying a constant shear rate to a random, static, isotropic assembly of identical, soft, frictional spheres at either zero or finite pressure by keeping constant the solid volume fraction until the steady state is reached. If the system is slowly sheared, or, equivalently, if the particles are sufficiently rigid, the granular material exhibits either large or small fluctuations in the evolving pressure, depending whether the average number of contacts per particle (coordination number) is less or larger than a critical value. The amplitude of the pressure fluctuations is rate-dependent when the coordination number is less than the critical and rate-independent otherwise, signatures of fluid-like and solid-like behaviour, respectively. The same critical coordination number has been previously found to represent the minimum value at which rate-independent components of the stresses develop in steady, simple shearing and the jamming transition in isotropic random packings. The observed complex behaviour of the measured pressure in the fluid-solid transition clearly suggests the need for incorporating in a nontrivial way the coordination number, the solid volume fraction, the particle stiffness and the intensity of the particle agitation in constitutive models for the onset and the arrest of granular flows.Comment: 20 pages, 14 figures, submitted to Granular Matte

    Adaptive Transactional Memories: Performance and Energy Consumption Tradeoffs

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    Energy efficiency is becoming a pressing issue, especially in large data centers where it entails, at the same time, a non-negligible management cost, an enhancement of hardware fault probability, and a significant environmental footprint. In this paper, we study how Software Transactional Memories (STM) can provide benefits on both power saving and the overall applications’ execution performance. This is related to the fact that encapsulating shared-data accesses within transactions gives the freedom to the STM middleware to both ensure consistency and reduce the actual data contention, the latter having been shown to affect the overall power needed to complete the application’s execution. We have selected a set of self-adaptive extensions to existing STM middlewares (namely, TinySTM and R-STM) to prove how self-adapting computation can capture the actual degree of parallelism and/or logical contention on shared data in a better way, enhancing even more the intrinsic benefits provided by STM. Of course, this benefit comes at a cost, which is the actual execution time required by the proposed approaches to precisely tune the execution parameters for reducing power consumption and enhancing execution performance. Nevertheless, the results hereby provided show that adaptivity is a strictly necessary requirement to reduce energy consumption in STM systems: Without it, it is not possible to reach any acceptable level of energy efficiency at all

    A phytosociological investigation on the mixed hemycryptophitic and therophitic grasslands of the Cornicolani mountains (Lazio Region – central Italy)

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    Abstract In this paper a phytosociological study on the dry grasslands of the Cornicolani mountains is presented. The Cornicolani are a group of isolated limestone hills which emerge from the slightly ondulating grounds of the Rome countryside in the Tyrrhenian side of the central Italy. Eighty-nine relevés were performed using the Braun-Blanquet phytosociological approach. These were further subjected to hierarchical classification and to NMDS ordination. Five major types of grasslands were distinguished: short therophytic grasslands developed on shallow soils dominated, in turns, by Hypochaeris achyrophorus, Plantago lagopus and Plantago bellardii; sub-nitrophilous detriticolous perennial grasslands dominated by Dittrichia viscosa and Helichrysum italicum; Dasypyrum villosum and Vulpia ligustica lawn and fallow annual tall-grasslands; Ampelodesmos mauritanicus grasslands of the rocky S-facing slopes and sub-mesophilous Lolium perenne and Cynodon dactylon grasslands of the flat and pastured areas. From a syntaxonomical standpoint a new associations named Plantaginetum afrae-bellardii was proposed and included in the class Stipo-Trachynetea. In addition the association Helichryso italici-Inuletum viscosae Trinajstić 1965 (nom. inval.) was here validated

    MiRNA-34 and stress response

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    Psychiatric disorders are known to result from a strong interaction between genetic predisposition and environmental factors, mainly exposure to stressful events. Environmental events can modulate genes expression, possibly via epigenetic mechanisms, and affect onset/expression of a disease [1]. Epigenetic mechanisms include, among others, post-transcriptional regulation by non-coding RNAs such as microRNAs (miRNAs). MiRNAs are small non-coding RNAs predicted to regulate hundreds of targets and to be engaged in every biological process [2]. Thanks to their ability to fine-tune gene expression, miRNAs can control gene expression patterns favoring organism’s adaptation to internal and environmental (external) factors [3], such as stressful events

    Visualizing Co-Phylogenetic Reconciliations

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    We introduce a hybrid metaphor for the visualization of the reconciliations of co-phylogenetic trees, that are mappings among the nodes of two trees. The typical application is the visualization of the co-evolution of hosts and parasites in biology. Our strategy combines a space-filling and a node-link approach. Differently from traditional methods, it guarantees an unambiguous and `downward' representation whenever the reconciliation is time-consistent (i.e., meaningful). We address the problem of the minimization of the number of crossings in the representation, by giving a characterization of planar instances and by establishing the complexity of the problem. Finally, we propose heuristics for computing representations with few crossings.Comment: This paper appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

    Arrhythmogenic right ventricular cardiomyopathy associated with severe left ventricular involvement in a cat.

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    An 8-year-old, 4 kg, intact female, domestic shorthaired cat was referred for tachypnea and pleural effusion. A 24-h Holter recording showed numerous polymorphic ventricular premature complexes with left and right bundle branch block morphology. Echocardiographic examination revealed right atrial and ventricular dilation. The right ventricular free wall was thin and aneurysmal. The cat died 10 days after initiation of antiarrhythmic therapy. Gross and histopathological findings were consistent with arrhythmogenic right ventricular cardiomyopathy (ARVC) associated with severe left ventricular involvement

    Inverted perovskite solar cells with transparent hole transporting layer based on semiconducting nickel oxide

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    Perovskite (CH3NH3PbI3) solar cells (PSCs) were produced in the inverted architecture employing transparent nickel oxide (NiO) as hole transporting layer (HTL). The different functional layers of the photoconversion device were solution processed in ambient conditions the HTL of NiO being prepared via sol-gel and successively deposited by spin-coating. The conditions of preparation of the transparent HTL were optimized through the stabilization of the nickel-containing sol with bulky alcohols and strong inorganic acids. The photoactive layer of CH3NH3PbI3 was deposited in air at high relative humidity (ca. 50-60%). The electron selective contact was constituted by spin coated 3H-cyclopropa[1,9] [5,6]fullerene-C60-Ih-3'-butanoic acid 3'-phenyl methyl ester (PCBM) with solution processed 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, BCP) as interlayer. The deposition of CH3NH3PbI3 in ambient conditions as well as the processing of the BCP interlayer from solution simplified enormously the entire procedure of device fabrication. The largest value of photoconversion efficiency (PCE) we achieved with the inverted architecture photocells was 14 % with an average PCE of 12 %. The solar cells displayed an hysteresis-free behavior with excellent time stability of the maximum power output
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