615 research outputs found

    Quality aware selective ECC for approximate DRAM

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    Approximate DRAMs are DRAM memories where energy saving techniques have been implemented by trading off bit-cell error rate with power consumption. They are considered part of the building blocks in the larger area of approximate computing. Relaxing refresh rate has been proposed as an interesting solution to achieve better efficiency at the expense of rising error rate. However, some works have demonstrated that much better results are achieved if at word-level some bits are retained without errors (i.e. their cells are refreshed at nominal rate), resulting in architectures using multiple refresh rates. In this paper we present a technique that can be applied to approximate DRAMs under reduced refresh rate. It allows to trim error rate at word-level, while still performing the refresh operation at the same rate for all cells. The number of bits that are protected is configurable and depends on output quality degradation that can be accepted by the application

    Hydrogen peroxide is a neuronal alarmin that triggers specific RNAs, local translation of Annexin A2, and cytoskeletal remodeling in Schwann cells

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    Schwann cells are key players in neuro-regeneration: They sense "alarm" signals released by degenerating nerve terminals and differentiate toward a proregenerative phenotype, with phagocytosis of nerve debris and nerve guidance. At the murine neuromuscular junction, hydrogen peroxide (H2O2) is a key signal of Schwann cells' activation in response to a variety of nerve injuries. Here we report that Schwann cells exposed to low doses of H2O2 rewire the expression of several RNAs at both transcriptional and translational levels. Among the genes positively regulated at both levels, we identified an enriched cluster involved in cytoskeleton remodeling and cell migration, with the Annexin (Anxa) proteins being the most represented family. We show that both Annexin A2 (Anxa2) transcript and protein accumulate at the tips of long pseudopods that Schwann cells extend upon H2O2 exposure. Interestingly, Schwann cells reply to this signal and to nerve injury by locally translating Anxa2 in pseudopods, and undergo an extensive cytoskeleton remodeling. Our results show that, similarly to neurons, Schwann cells take advantage of local protein synthesis to change shape and move toward damaged axonal terminals to facilitate axonal regeneration

    Solid-state cultures of Fusarium oxysporum transform aromatic components of olive-mill dry residue and reduce its phytotoxicity

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    The present study mainly investigated the ability of solid-state cultures of the non-pathogenic Fusarium oxysporum strain BAFC 738 to transform aromatic components to reduce the phytotoxicity in olive-mill dry residue (DOR), the waste from the two-phase manufacturing process. Lignin, hemicellulose, fats and water-soluble extractives contents of DOR colonized by the fungus for 20 weeks were reduced by 16%, 25%, 71% and 13%, respectively, while the cellulose content increased by 25%. In addition, the ethyl acetate-extractable phenolic fraction of the waste was reduced by 65%. However, mass-balance ultra-Wltration and size-exclusion chromatography experiments suggested that the apparent removal of that fraction, mainly including 2-(3,4-dihydroxyphenyl)ethyl alcohol and 2-(4-hydroxyphenyl) ethyl alcohol, was due to polymerization. Mn-peroxidase and Mn-independent peroxidase activities were found in F. oxysporum solid-state cultures, while laccase and aryl alcohol oxidase activities were not detected. Tests performed with seedlings of tomato (Lycopersicum esculentum L.), soybean (Glycine maximum Merr.), and alfalfa (Medicago sativa L.) grown on soils containing 6% (w/w) of bioconverted DOR (kg soil)¡1 showed that the waste’s phytotoxicity was removed by 20 weeks-old fungal cultures. By contrast, the same material exhibited a high residual toxicity towards lettuce (Lactuca sativa L.).L'articolo é disponibile sul sito dell'editore: http://www.sciencedirect.co

    A GIS-based statistical approach to prioritize the retrofit of housing stocks at the urban scale

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    Cities are responsible for about 70% of the overall primary energy consumption in Europe and play a major role in addressing carbon mitigation. In this respect, the housing s ector has been identified as a key sector for its high energy savings potential achievable by implementing retrofit measures. However, a detailed characterization of the housing energy consumption profile and spatial distribution is needed to properly asse ss the energy saving potential at the urban scale and further support sustainable urban planning and energy policies. This study focused on a statistical approach based on Geographical Information Systems (GIS) developed to identify the energy consumption profile of urban housing stocks, the energy savings potential achievable by implementing retrofit measures and their respective spatial distribution across one entire city. The final energy consumption of individual dwellings was predicted by running a mul tiple linear regression model based on measured energy consumption available at aggregated level (post - code area level) and GIS data about characteristics of buildings and household. Energy savings potential and cost - effectiveness of standard retrofit meas ures were subsequently calculated and results were finally displayed as maps for decision support in sustainable urban planning. The methodology was applied to the exemplary housing stock of Rotterdam city, consisting of almost 300,000 units. Relevant res ults were provided to prioritize retrofit measures implementation according to energy savings potential and cost - effectiveness. Different types of maps were produced to show energy consumption and energy saving potential patterns across the city. The metho dology is generically applicable to other contexts and provides an effective tool for decision support in carbon mitigation policies of housing stocks at the urban scale

    Environmental effects on brain functional networks in a juvenile twin population

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    : The brain's intrinsic organization into large-scale functional networks, the resting state networks (RSN), shows complex inter-individual variability, consolidated during development. Nevertheless, the role of gene and environment on developmental brain functional connectivity (FC) remains largely unknown. Twin design represents an optimal platform to shed light on these effects acting on RSN characteristics. In this study, we applied statistical twin methods to resting-state functional magnetic resonance imaging (rs-fMRI) scans from 50 young twin pairs (aged 10-30 years) to preliminarily explore developmental determinants of brain FC. Multi-scale FC features were extracted and tested for applicability of classical ACE and ADE twin designs. Epistatic genetic effects were also assessed. In our sample, genetic and environmental effects on the brain functional connections largely varied between brain regions and FC features, showing good consistency at multiple spatial scales. Although we found selective contributions of common environment on temporo-occipital connections and of genetics on frontotemporal connections, the unique environment showed a predominant effect on FC link- and node-level features. Despite the lack of accurate genetic modeling, our preliminary results showed complex relationships between genes, environment, and functional brain connections during development. A predominant role of the unique environment on multi-scale RSN characteristics was suggested, which needs replications on independent samples. Future investigations should especially focus on nonadditive genetic effects, which remain largely unexplored

    The 1980 earthquake in southern Italy: rescue of trapped victims and mortality.

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    A retrospective survey was undertaken on the health effects of the 1980 earthquake in southern Italy. The study population included 3619 people living in 7 villages situated near the epicentre of the disaster. The overall casualty rate (dead and injured) was 19.7%. Nearly all the deaths (192/202) occurred among trapped people who died before they could be rescued. Eighty per cent of all the trapped people were extricated within 2 days, mostly without the use of sophisticated means. The probability of survival decreased sharply, the longer the time before extrication. The crude mortality during the 18 months following the earthquake was 19.0 per thousand among the injured people who received treatment, and 14.1 per thousand among non-injured people. After age standardization, there was no significant difference between these two figures and the expected mortality figures for the Italian population in normal times (14.4 per thousand). These results stress the importance of providing rescue activities in the first 48 hours after the impact. Strengthening the self-reliance of the community in disaster preparedness is suggested as the best way to improve the effectiveness of relief operations. In disaster-prone areas, training and education in methods of rescue should be an integral part of any primary health care programme

    What are the effects of maternal and pre-adult environments on ageing in humans, and are there lessons from animal models?

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    An open issue in research on ageing is the extent to which responses to the environment during development can influence variability in life span in animals, and the health profile of the elderly in human populations. Both affluence and adversity in human societies have profound impacts on survivorship curves, and some of this effect may be traceable to effects in utero or in infancy. The Barker Hypothesis that links caloric restriction in very early life to disruptions of glucose-insulin metabolism in later life has attracted much attention, as well as some controversy, in medical circles. It is only rarely considered by evolutionary biologists working on phenotypic plasticity, or by biogerontologists studying model organisms such as C. elegans or Drosophila. One crucial mechanism by which animals can respond in an adaptive manner to adverse conditions, for example in nutrition or infection, during development is phenotypic plasticity. Here we begin with a discussion of adaptive plasticity in animals before asking what such phenomena may reveal of relevance to rates of ageing in animals, and in humans. We survey the evidence for effects on adult ageing of environmental conditions during development across mammalian and invertebrate model organisms, and ask whether evolutionary conserved mechanisms might be involved. We conclude that the Barker Hypothesis is poorly supported and argue that more work in human populations should be integrated with multi-disciplinary studies of ageing-related phenomena in experimental populations of different model species that are subjected to nutritional challenges or infections during pre-adult development

    Reproductive life disorders in Italian celiac women. A case-control study

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    BACKGROUND: The aim of this study is to explore the association between celiac disease and menstrual cycle, gestation and puerperal disorders. METHODS: The association between celiac disease and menstrual cycle, gestation and puerperal disorders in a sample of 62 childbearing age women (15-49 age) was assessed within an age and town of residence matched case-control study conducted in 2008. Main outcome measures were the presence of one or more disorders in menstrual cycle and the presence of one or more complication during pregnancy. RESULTS: 62 celiac women (median age: 31.5, range: 17-49) and 186 healthy control (median age: 32.5, range: 15-49) were interviewed. A higher percentage of menstrual cycle disorders has been observed in celiac women. 19.4% frequency of amenorrhea was reported among celiac women versus 2.2% among healthy controls (OR = 33, 95% CI = 7.17-151.8;, p = 0.000). An association has been observed between celiac disease and oligomenorrhea, hypomenorrhea, dysmenorrhea and metrorrhagia (p < 0.05). The likelihood of having at least one complication during pregnancy has been estimated to be at least four times higher in celiac women than in healthy women (OR = 4.1, 95% CI = 2-8.6, p = 0.000). A significant correlation has emerged for celiac disease and threatened abortion, gestational hypertension, placenta abruption, severe anaemia, uterine hyperkinesia, intrauterine growth restriction (p < 0.001). A shorter gestation has on average been observed in celiac women together with a lower birth weight of celiac women babies (p < 0.001). CONCLUSIONS: The occurrence of a significant correlation between celiac disease and reproductive disorders could suggest to consider celiac disease diagnostic procedures (serological screening) in women affected by these disorders

    Design and evaluation of artificial controllers assisting voluntary balance performance in paraplegia and in stroke

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    The mobility impairment caused by a paralysis like a spinal cord injury or a stroke has, beside many other impacts, an influence on the transfer of signals between the muscles of the lower extremities and the brain. In a paraplegic person, this means that she or he can not stand without holding onto a support or standing in a standing frame while the impact on the ability to balance in a hemiplegic person can be less severe. Although the connection between the muscles and the brain is impaired by the injury, the muscles still retain the ability to contract if innervated. This thesis describes control approaches which combine the remaining voluntary control of the paraplegic and stroke patients with the artificially controlled stimulation of the muscles of the paralysed limbs to aid the subject in balancing. The aim was to develop new control approaches which would assist balance in paraplegic subjects and in stroke. To support standing in paraplegic subjects, the moment generated at the ankle using electrical stimulation of the shank muscles was integrated with the voluntary control of the upper body, resulting in the concept of Integrated Voluntary Control (IVC). In the outer loop the ankle moment produced by the paraplegic subject due to his voluntary upper body movement was estimated using a mathematical model based on the inclination angles of upper and lower body. This estimated ankle moment was then compared with the actual moment applied at the force plates the subject was standing on, and an appropriate stimulation signal was applied to the paralysed shank muscles. Experimental evaluation initially involved four able bodied volunteers in which base line results with stiffness and stiffness-viscosity controllers using a rotating standing platform were obtained. This was extended to the paraplegic subject, where electrical muscle stimulation was used to generate the required ankle moment. The IVC concept was then evaluated with the paraplegic subject and compared to the base line results. Due to the nature of the system and implied perturbation onto the control system controlling the posture of the paraplegic subject the known evaluation values (e.g. rise time, steady state value, overshoot value etc.) are not suitable. Therefore, the variance of a time signal around its mean value was used as an evaluation value which allowed to compare the achieved performance of the paraplegic subject employing the new control approach with the stiffness and stiffness-viscosity controllers directly. To assist balance in stroke patients, a new training approach was introduced based on the concept of integrating the voluntary abilities of the patient with mechanical balance support and sensory electrical stimulation. This concept was evaluated in a training program with one stroke subject which demonstrated the feasibility and potential balance improvement resulting from this approach.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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