986 research outputs found

    (B)On(e)-cohistones and the epigenetic alterations at the root of bone cancer

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    Identification of mutations in histones in a number of human neoplasms and developmental syndromes represents the most compelling evidence to date for a causal role of epigenetic perturbations in human disease. In most cases, these mutations have gain of function properties that cause deviation from normal developmental processes leading to embryo defects and/or neoplastic transformation. These exciting discoveries represent a step-change in our understanding of the role of chromatin (dys)regulation in development and disease. However, the mechanisms of action of oncogenic histone mutations (oncohistones) remain only partially understood. Here, we critically assess existing literature on oncohistones focussing mainly on bone neoplasms. We show how it is possible to draw parallels with some of the cell-autonomous mechanisms of action described in paediatric brain cancer, although the functions of oncohistones in bone tumours remain under-investigated. In this respect, it is becoming clear that histone mutations targeting the same residues display, at least in part, tissue-specific oncogenic mechanisms. Furthermore, it is emerging that cancer cells carrying oncohistones can modify the surrounding microenvironment to support growth and/or alter differentiation trajectories. A better understanding of oncohistone function in different neoplasms provide potential for identification of signalling that could be targeted therapeutically. Finally, we discuss some of the main concepts and future directions in this research area, while also drawing possible connections and parallels with other cancer epigenetic mechanisms

    Designing human-centric software artifacts with future users: a case study

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    The quality and quantity of participation supplied by human beings during the different phases of the design and development of a software artifact are central to studies in human-centered computing. With this paper, we have investigated on what kind of experienced people should be engaged to design a new computational artifact, when a participatory approach is adopted. We compared two approaches: the former including only future users (i.e., novices) in the design process, and the latter enlarging the community to expert users. We experimented with the design of a large software artifact, in use at the University of Bologna, engaging almost 1500 users. Statistical methodologies were employed to validate our findings. Our analysis has provided mounting evidence that expert users have contributed to the design of the artifact only by a small amount. Instead, most of the innovative initiatives have come from future users, thus surpassing some traditional limitations that tend to exclude future users from this kind of processes. We here challenge the traditional opinion that expert users provide typically a more reliable contribution in a participatory software design process, demonstrating instead that future users would be often better suited. Along this line of sense, this is the first paper, in the field of human-centric computing, that discusses the relevant question to offer to future users a larger design space, intended as a higher level of freedom given in a software design situation, demarcated by precise design constraints. In this sense, the outcome has been positiv

    Raveguard: A noise monitoring platform using low-end microphones and machine learning

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    Urban noise is one of the most serious and underestimated environmental problems. According to the World Health Organization, noise pollution from traffic and other human activities, negatively impact the population health and life quality. Monitoring noise usually requires the use of professional and expensive instruments, called phonometers, able to accurately measure sound pressure levels. In many cases, phonometers are human-operated; therefore, periodic fine-granularity city-wide measurements are expensive. Recent advances in the Internet of Things (IoT) offer a window of opportunities for low-cost autonomous sound pressure meters. Such devices and platforms could enable fine time\u2013space noise measurements throughout a city. Unfortunately, low-cost sound pressure sensors are inaccurate when compared with phonometers, experiencing a high variability in the measurements. In this paper, we present RaveGuard, an unmanned noise monitoring platform that exploits artificial intelligence strategies to improve the accuracy of low-cost devices. RaveGuard was initially deployed together with a professional phonometer for over two months in downtown Bologna, Italy, with the aim of collecting a large amount of precise noise pollution samples. The resulting datasets have been instrumental in designing InspectNoise, a library that can be exploited by IoT platforms, without the need of expensive phonometers, but obtaining a similar precision. In particular, we have applied supervised learning algorithms (adequately trained with our datasets) to reduce the accuracy gap between the professional phonometer and an IoT platform equipped with low-end devices and sensors. Results show that RaveGuard, combined with the InspectNoise library, achieves a 2.24% relative error compared to professional instruments, thus enabling low-cost unmanned city-wide noise monitoring

    Aspectos ambientais do cultivo de arroz orgânico, biodinâmico e convencional.

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    Este trabalho tem o objetivo de comparar aspectos ambientais dos diferentes sistemas manejo de arroz irrigado orgânico, biodinâmico e convencional.SIAPEX

    New Trends in Designing Parabolic trough Solar Concentrators and Heat Storage Concrete Systems in Solar Power Plants

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    Energy availability has always been an essential component of human civilization and the energetic consumption is directly linked to the produced wealth. In many depressed countries the level of solar radiation is considerably high and it could be the primary energy source under conditions that low cost, simple-to-be-used technologies are employed. Then, it is responsibility of the most advanced countries to develop new equipments to allow this progress for taking place. A large part of the energetic forecast, based on economic projection for the next decades, ensure us that fossil fuel supplies will be largely enough to cover the demand. The predicted and consistent increase in the energetic demand will be more and more covered by a larger use of fossil fuels, without great technology innovations. A series of worrying consequences are involved in the above scenario: important climatic changes are linked to strong CO2 emissions; sustainable development is hindered by some problems linked to certainty of oil and natural gas supply; problems of global poverty are not solved but amplified by the unavoidable increase in fossil fuel prices caused by an increase in demand. These negative aspects can be avoided only if a really innovative and more acceptable technology will be available in the next decades at a suitable level to impress a substantial effect on the society. Solar energy is the ideal candidate to break this vicious circle between economic progress and consequent greenhouse effect. The low penetration on the market shown today by the existent renewable technologies, solar energy included, is explained by well-known reasons: the still high costs of the produced energy and the \u201cdiscontinuity\u201d of both solar and wind energies. These limitations must be removed in reasonable short times, with the support of innovative technologies, in view of such an urgent scenario. On this purpose ENEA, on the basis of the Italian law n. 388/2000, has started an R&D program addressed to the development of CSP (Concentrated Solar Power) systems able to take advantage of solar energy as heat source at high temperature. One of the most relevant objectives of this research program (Rubbia, 2001) is the study of CSP systems operating in the field of medium temperatures (about 550\ub0C), directed towards the development of a new and low-cost technology to concentrate the direct radiation and efficiently convert solar energy into high temperature heat; another aspect is focused on the production of hydrogen by means of thermo-chemical processes at temperatures above 800\ub0C. As well as cost reductions, the current innovative ENEA conception aims to introduce a set of innovations, concerning: i) The parabolic-trough solar collector: an innovative design to reduce production costs, installation and maintenance and to improve thermal efficiency is defined in collaboration with some Italian industries; ii) The heat transfer fluid: the synthetic hydrocarbon oil, which is flammable, expensive and unusable beyond 400\ub0C, is substituted by a mixture of molten salts (sodium and potassium nitrate), widely used in the industrial field and chemically stable up to 600\ub0C; iii) The thermal storage (TES): it allows for the storage of solar energy, which is then used when energy is not directly available from the sun (night and covered sky) (Pilkington, 2000). After some years of R&D activities, ENEA has built an experimental facility (defined within the Italian context as PCS, \u201cProva Collettori Solari\u201d) at the Research Centre of Casaccia in Rome (ENEA, 2003), which incorporates the main proposed innovative elements. The next step is to test these innovations at full scale by means of a demonstration plant, as envisioned by the \u201cArchimede\u201d ENEA/ENEL Project in Sicily. Such a project is designed to upgrade the ENEL thermo-electrical combined-cycle power plant by about 5 MW, using solar thermal energy from concentrating parabolic-trough collectors. Particularly, the Chapter will focus on points i) and iii) above: - loads, actions, and more generally, the whole design procedure for steel components of parabolic-trough solar concentrators will be considered in agreement with the Limit State method, as well as a new approach will be critically and carefully proposed to use this method in designing and testing \u201cspecial structures\u201d such as the one considered here; - concrete tanks durability under prolonged thermal loads and temperature variations will be estimated by means of an upgraded F.E. coupled model for heat and mass transport (plus mechanical balance). The presence of a surrounding soil volume will be additionally accounted for to evaluate environmental risk scenarios. Specific technological innovations will be considered, such as: -higher structural safety related to the reduced settlements coming from the chosen shape of the tank (a below-grade cone shape storage); - employment of HPC containment structures and foundations characterized by lower costs with respect to stainless steel structures; - substitution of highly expensive corrugated steel liners with plane liners taking advantage of the geometric compensation of thermal dilations due to the conical shape of the tank; - possibility of employing freezing passive systems for the concrete basement made of HPC, able to sustain temperature levels higher than those for OPC; - fewer problems when the tank is located on low-strength soils

    Nonlinear Modelling, Design, and Test of Steel Blast-Resistant Doors

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    The nonlinear dynamic response for steel blast-resistant doors is here described, referring to an innovative experience at both national and international level requiring an ad hoc design and specific numerical simulations. The elements capability to sustain thermal loads due to fire hazards is additionally accounted for. The study has been conducted to define and characterize the nonlinear behaviour of a large number of doors, with the objective of sustaining dynamic loads from explosive hazards of fixed magnitude, as well as variable design and clearing times. The local overcome of the material strength limit (with correspondent plastic response) and possible formation of plastic hinges has been critically discussed. Numerical models have allowed for refining first design sketches and subsequently understanding the real thermomechanical behaviour for the investigated elements. Some experimental tests have been additionally performed, verifying the correctness of the already available numerical results, validating the adopted procedures, and correspondingly guaranteeing the doors' structural efficiency even under dynamic loads higher than design ones

    Ultrafast emission from colloidal nanocrystals under pulsed X-ray excitation

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    Fast timing has emerged as a critical requirement for radiation detection in medical and high energy physics, motivating the search for scintillator materials with high light yield and fast time response. However, light emission rates from conventional scintillation mechanisms fundamentally limit the achievable time resolution, which is presently at least one order of magnitude slower than required for next-generation detectors. One solution to this challenge is to generate an intense prompt signal in response to ionizing radiation. In this paper, we present colloidal semiconductor nanocrystals (NCs) as promising prompt photon sources. We investigate two classes of NCs: two-dimensional CdSe nanoplatelets (NPLs) and spherical CdSe/CdS core/giant shell quantum dots (GS QDs). We demonstrate that the emission rates of these NCs under pulsed X-ray excitation are much faster than traditional mechanisms in bulk scintillators, i.e. 5d-4f transitions. CdSe NPLs have a sub-100 ps effective decay time of 77 ps and CdSe/CdS GS QDs exhibit a sub-ns value of 849 ps. Further, the respective CdSe NPL and CdSe/CdS GS QD X-ray excited photoluminescence have the emission characteristics of excitons (X) and multiexcitons (MX), with the MXs providing additional prospects for fast timing with substantially shorter lifetimes

    Conceptual Study of a Thermal Storage Module for Solar Power Plants with Parabolic Trough Concentrators

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    The thermal storage technology (TSE) has a relevant strategic importance for the success of solar plants devoted to electric energy and heat production. The major benefits in the use of storage include higher efficiency and reduction in the mean levelled cost of the electric energy unit (LEC). Sensible heat storage systems within solid media have been identified, both technically and economically, as a very promising solution. The development of such a storage technology, adopting concrete, could reduce the specific cost to less than 20\u20ac per kWh of thermal capacity; additionally, such a solution is suitable for small-medium size plants with a power ranging from 1 MW to 5 MW, to be easily introduced in the Italian territory and with reduced operational and maintenance needs. In large size CSP systems, as the ARCHIMEDE plant built by ENEL with ENEA technology, a high temperature fluid storage (between 400 and 500\ub0C) is required. Such a temperature seems at present not adequate to allow for adopting concrete, whereas the production of concrete able to sustain 250-300\ub0C appears as a reachable objective. It is supposed to study a storage system characterised by a parallelepiped structure with appropriate section, selfbearing and supported on its major axis, as well as by a piping system directing the thermovector fluid within the cemented matrix

    Sistema e custo de produção de gado de corte no Estado do Rio Grande do Sul - região da Campanha.

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    Programa da pecuária de corte no Rio Grande so Sul. Descrição do sistema de produção de gado de corte da região da campanha - Rio Grande do Sul. Benfeitoria, máquinas e equipamentos. Composição do rebanho e desempenho zootécnico. Controle sanitário. Mão de obra. Sistema gerancial e contábil. Resultados econômicos do sistema modal de cria, recria e engorda. Estrutua de custos. Receita e sua composição. Custo de produção e margens econômicas. Custos de produção variando a capacidade de suporte dos pastos e a taxa de natalidade. Considerações finais.bitstream/item/79815/1/COT95.pdfCNPGC
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