1,064 research outputs found
Deliberation across Deep Divisions. Transformative Moments
In group discussions of any kind there tends to be an up and down in the level of deliberation. To capture this dynamic we coined the concept of Deliberative Transformative Moments (DTM). In deeply divided societies deliberation is particularly important in order to arrive at peace and stability, but deliberation is also very difficult to be attained. Therefore, we wanted to learn about the conditions that in group discussions across the deep divisions of such societies help deliberation. We organized such group discussions between ex-guerrillas and ex-paramilitaries in Colombia, Serbs and Bosnjaks in Srebrenica, and poor residents and local police officers in the favelas (slums) of Brazil. We could identify factors that help to transform discussions from low to high deliberation and risk transformations in the opposite direction. We could also identify factors that help to keep a discussion at a high level of deliberation, and, in a next step, we could determine to what extent long sequences of deliberation had a positive impact on the outcomes of the discussions. Finally, we show how our research results can have a long term effect if it is used in schools of such deeply divided societies
Deliberation across Deep Divisions. Transformative Moments
From the local level to international politics, deliberation helps to increase mutual understanding and trust, in order to arrive at political decisions of high epistemic value and legitimacy. This book gives deliberation a dynamic dimension, analysing how levels of deliberation rise and fall in group discussions, and introducing the concept of 'deliberative transformative moments' and how they can be applied to deeply divided societies, where deliberation is most needed but also most difficult to work. Discussions between ex-guerrillas and ex-paramilitaries in Colombia, Serbs and Bosnjaks in Bosnia-Herzegovina, and police officers and locals in Brazilian favelas are used as case studies, with participants addressing how peace can be attained in their countries. Allowing access to the records and transcripts of the discussions opens an opportunity for practitioners of conflict resolution to apply this research to their work in trouble spots of the world, creating a link between the theory and practice of deliberation
Mechanisms of synaptic depression triggered by metabotropic glutamate receptors
Abstract.: Glutamate, by activation of metabotropic receptors (mGluRs), can lead to a reduction of synaptic efficacy at many synapses. These forms of synaptic plasticity are referred to as long-term depression (mGluR-LTD). We will distinguish between mGluR-LTD induced by pre- or postsynaptic receptors and mGluR-LTD induced by the locus of the expression mechanism of the synaptic depression. We will also review recent evidence that mGluR-mediated responses themselves are subject to depression, which may constitute a form of metaplasticit
Experimental analysis and transient numerical simulation of a large diameter pulsating heat pipe in microgravity conditions
A multi-parametric transient numerical simulation of the start-up of a large diameter Pulsating Heat Pipe (PHP) specially designed for future experiments on the International Space Station (ISS) are compared to the results obtained during a parabolic flight campaign supported by the European Space Agency. Since the channel diameter is larger than the capillary limit in normal gravity, such a device behaves as a loop thermosyphon on ground and as a PHP in weightless conditions; therefore, the microgravity environment is mandatory for pulsating mode. Because of a short duration of microgravity during a parabolic flight, the data concerns only the transient start-up behavior of the device. One of the most comprehensive models in the literature, namely the in-house 1-D transient code CASCO (French acronym for Code Avancé de Simulation du Caloduc Oscillant: Advanced PHP Simulation Code in English), has been configured in terms of geometry, topology, material properties and thermal boundary conditions to model the experimental device. The comparison between numerical and experimental results is performed simultaneously on the temporal evolution of multiple parameters: tube wall temperature, pressure and, wherever possible, velocity of liquid plugs, their length and temperature distribution within them. The simulation results agree with the experiment for different input powers. Temperatures are predicted with a maximum deviation of 7%. Pressure variation trend is qualitatively captured as well as the liquid plug velocity, length and temperature distribution. The model also shows the ability of capturing the instant when the fluid pressure begins to oscillate after the heat load is supplied, which is a fundamental information for the correct design of the engineering model that will be tested on the ISS. We also reveal the existence of strong liquid temperature gradients near the ends of liquid plugs both experimentally and by simulation. Finally, a theoretical prediction of the stable functioning of a large diameter PHP in microgravity is given. Results show that the system provided with an input power of 185W should be able to reach the steady state after 1min and maintain a stable operation from then on
CORRELATION BETWEEN CHRONIC MUCOSAL TRAUMA AND ORAL CANCER: A CASE REPORT AND REVIEW OF THE LITERATURE
Abstract – Objective: Squamous cell carcinoma is the most common malignancy in the oral cavity
representing the 90% of all oral malignancies that affect oral cavity. Primary risk factors associated
with oral cancer are alcohol and tobacco consumption. However, other emerging risk factors have
been proposed in Literature, including chronic trauma of the oral mucosa related to dental prostheses and incongruous restorations. Therefore, the aim of this study was to review the literature on the
correlation between oral carcinoma and chronic irritative trauma, with the help of a case report and
with focus on clinical features and differential diagnosis.
Materials and Methods: A literature search on MEDLINE, PubMed, ScienceDirect, Cochrane
Database of Systematic Reviews and Wiley InterScience was performed, using the following words:
Oral Cancer, chronic Trauma and Denture Trauma in various combinations.
Results: The review produced 1356 results, but only 8 articles met the inclusion criteria and were
involved in the review. No association has been proven between chronic mucosal trauma and oral
cancer. Carcinoma has been shown to develop more frequently in trauma regions, particularly in
the tongue. As for the data on the gender and age of affected patients, it emerges that most of the
greatest incidence occurs around the sixth and seventh decade of life and men are more affected
than women.
Conclusions: Due to the heterogeneity of the different studies and the strong presence of
other factors such as smoking and alcohol, the role of trauma in carcinogenesis is unclear. Further
molecular, epidemiological and case-control studies are needed to define this correlation. It is advisable to carry out more restricted checks in patients at risk with dental prostheses
Experimental analysis of the thermal energy storage potential of a phase change material embedded in additively manufactured lattice structures
Recent literature introduced novel additively manufactured porous metallic structures designed to deliver enhancement of the thermal conductivity of organic phase change materials. Among these, so-called lattice structures are of particular interest for application in lightweight components. Originally investigated for their attractive mass-specific mechanical properties, these geometries were recently proposed, in alternative to metallic foams, as a conductive matrix of phase change materials. However, the geometrical parameters of a lattice structure differ from the ones of a metallic foam and no established data exist in the literature about the influence of the lattice cell geometry on the transient heat transfer enhancement of a phase change material. This work presents an experimental comparison of the thermal behaviour of a composite based on an n-Octadecane paraffin wax embedded in four different aluminium lattices with varying unit cell topology (f2ccz, bcc, bccz, f2bcc), but showing the same cell size, aspect ratio and strut diameter. It is noticed that the unit cell topology affects the transient thermal behaviour beyond its direct effect on the cell porosity. To address this, a specific thermal performance parameter is identified. The sample based on the f2ccz topology represents the best candidate. The influence of orientation with respect to gravity on the heat transfer is also investigated. While the samples show relatively low porosity, ranging from 70.7% to 83.4%, the wide pore diameters lead to a high impact of melt convection on the thermal behaviour of most samples. Up to 28% wall temperature variation is evidenced for different heating orientations
Heat transfer delay method for the fluid velocity evaluation in a multi-turn pulsating heat pipe
A multi-turn closed loop pulsating heat pipe made of aluminium is tested in vertical bottom heated mode and
different condenser temperatures with the aim of providing quantitative information regarding its flow dynamics
through a novel post-processing technique on the local wall-to-fluid heat flux, evaluated within the adiabatic
section. The studied device is made of an annealed aluminium tube (inner/outer diameter: 3/5 mm), folded in 14
turns and partially filled with methanol (volumetric filling ratio: 50%). The aluminium channels are coated with
a high-emissivity opaque paint, thus allowing thermographic measurements on the outer wall by means of a
high-resolution medium wave infrared camera. The proposed method, named Heat Transfer Delay Method, is
validated by means of a dedicated experimental approach. Then, the acquired time-space temperature maps are
used as input data for the inverse heat conduction problem resolution approach to estimate the local convective
heat flux locally exchanged at the inner wall-fluid interface. The resulting wall-to-fluid heat fluxes are then post-
processed by applying the Heat Transfer Delay Method to the oscillatory and circulatory flow modes. The average
fluid velocity is assessed at varying working conditions during the circulatory flow, finding values up to 0.77 m/s
and 0.3 m/s for condenser temperature equal to 20 â—¦C and 10 â—¦ C, respectivel
Effect of the Ambient Temperature on the Start-Up of a Multi-Evaporator Loop Thermosyphon
Two-phase heat transfer devices are becoming fairly ubiquitous; the capability to transport heat at high rates over appreciable distances, without any external pumping device, the low cost, durability and relatively simpler modeling/design process, make this technology very attractive for many thermal management applications. Indeed, such devices have been investigated in plenty of fields such as: nuclear plants, energy systems, solar heat recovery, air conditioning, electronic cooling in avionics and in railway traction. As a consequence, they can operate under different environmental conditions that can affect their behavior. Nevertheless, it is difficult to find in literature something related to the effect of the ambient temperature on the thermal performance of such devices. The actual temperature, varying the thermo-fluid properties of the fluid inside the device, the condensation and the evaporation phenomena, could be an important parameter that can affect the performance. In this work a Multi-Evaporator loop thermosyphon is tested at different ambient temperatures, ranging from -20 °C up to 30 °C. The start-up behavior, as well as the thermal performance, are analyzed by means of temperature and pressure measurements and fluid flow visualization
On the thermal and hydrothermal stability of spinel iron oxide nanoparticles as single and core-shell hard-soft phases
The thermal and hydrothermal stability of oleate-capped nanosized spinel iron oxides is of primary importance for the plethora of applications and environments for which they are employed. An in-situ XRD and ex-situ autoclave treatments have been set up for monitoring the thermal and hydrothermal stability in different samples. In detail, spinel iron oxide nanoparticles (NPs) were studied as (i) single-phase alone at three different sizes (about 6, 10, and 15 nm); (ii) as core in a core-shell architecture having cobalt ferrite as shell, at different core sizes (about 6 and 10 nm); (iii) as shell in a core-shell architecture with cobalt ferrite as core, at different shell thicknesses (about 3 and 4 nm). The Rietveld refinement of the diffraction patterns and 57Fe Mössbauer spectroscopy have been exploited to monitor the evolution of the structural parameters and the hematite fraction. Moreover, transmission electron microscopy has permitted to deepen the morphological details on the phases. The spinel iron oxide-hematite transition has been found size- and time-dependent for the single-phase iron oxide NPs (360–455 °C). The transition temperature has increased significantly when iron oxide is incorporated in a core-shell architecture, both as core (630 °C) and shell (520 °C), suggesting a stabilizing effect of cobalt ferrite. The hydrothermal stability of iron oxide and core-shell NPs has been found dependent on water content, time, and temperature, with a reducing effect of pentanol toward the formation of magnetite from maghemite, highlighted by 57Fe Mössbauer spectroscopy. The synergic effects of cobalt ferrite and pentanol have limited the formation of hematite, leading to the obtainment of magnetite-covered cobalt ferrite NPs upon the hydrothermal treatment
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