4,747 research outputs found

    Quantization of Soliton Cellular Automata

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    A method of quantization of classical soliton cellular automata (QSCA) is put forward that provides a description of their time evolution operator by means of quantum circuits that involve quantum gates from which the associated Hamiltonian describing a quantum chain model is constructed. The intrinsic parallelism of QSCA, a phenomenon first known from quantum computers, is also emphasized.Comment: Latex, 6 pages, 1 figure in eps format included. Submitted to Journal of Nonlinear Mathematical Physics. Special Issue of Proccedings of NEEDS'9

    Searching edges in the overlap of two plane graphs

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    Consider a pair of plane straight-line graphs, whose edges are colored red and blue, respectively, and let n be the total complexity of both graphs. We present a O(n log n)-time O(n)-space technique to preprocess such pair of graphs, that enables efficient searches among the red-blue intersections along edges of one of the graphs. Our technique has a number of applications to geometric problems. This includes: (1) a solution to the batched red-blue search problem [Dehne et al. 2006] in O(n log n) queries to the oracle; (2) an algorithm to compute the maximum vertical distance between a pair of 3D polyhedral terrains one of which is convex in O(n log n) time, where n is the total complexity of both terrains; (3) an algorithm to construct the Hausdorff Voronoi diagram of a family of point clusters in the plane in O((n+m) log^3 n) time and O(n+m) space, where n is the total number of points in all clusters and m is the number of crossings between all clusters; (4) an algorithm to construct the farthest-color Voronoi diagram of the corners of n axis-aligned rectangles in O(n log^2 n) time; (5) an algorithm to solve the stabbing circle problem for n parallel line segments in the plane in optimal O(n log n) time. All these results are new or improve on the best known algorithms.Comment: 22 pages, 6 figure

    Towards a low-carbon economy : A nexus-oriented policy coherence analysis in Greece

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    The sustainable management of natural resources under climate change conditions is a critical research issue. Among the many approaches emerged in recent times, the so-called 'nexus approach' is gaining traction in academic and policy circles. The nexus approach presupposes the analysis of bio-physical, socio-economic and policy interlinkages among sectors (e.g., water, energy, food) for the identification of integrated solutions and the support of policy decisions. Ultimately, the nexus approach aims to identify synergies and trade-offs among the nexus dimensions. Concerning policy, the nexus approach focuses on policy coherence, i.e., the systematic identification and management of trade-offs and synergies between policies across sectors. This paper investigates the coherence between policies on the water-land-energy-food-climate nexus in Greece. The systematic analysis of policy documents led to the elicitation of nexus-related policy objectives and instruments. Then, the coherence among objectives and between objectives and instruments was assessed using the methodology proposed by Nilsson et al. A stakeholder (trans-disciplinary) orientation was adopted and the need to incorporate stakeholders' recommendations as to policy coherence assessment was highlighted. Overall, the findings revealed that climate and food/agricultural policies represent critical future priorities in Greece by stimulating progress in other nexus-related policies (energy, water, land policies) and being positively influenced by them.</p

    Geotechnical foundation conditions of Mesologion swimming pool center

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    Η επιλογή του καταλληλότερου τύπου θεμελίωσης εμπεριέχει την εξέταση ποικίλλων παραμέτρων. Στην περίπτωση του Κολυμβητηρίου Μεσολογγίου, έγινε μια προσπάθεια πρότασης ενός τύπου θεμελίωσης, κατάλληλου από γεωτεχνικής πλευράς, για ιζήματα που βρίσκονται πολύ κοντά στη θάλασσα. Το υπέδαφος εκεί, αποτελείται από μαλακά, λεπτόκοκκα, χαμηλής πλαστικότητας υλικά, CL μέχρι SL, με εναλλαγές υψηλής πλαστικότητας αργιλικών στρωμάτων CH. Επιπρόσθετα η στάθμη του υπόγειου υδροφόρου εντοπίζεται στα 0,8 μέτρα κάτω από την επιφάνεια του εδάφους. Ή δυσκολία εξασφάλισης αδιατάραχτων δειγμάτων λόγω κατάστασης υλικού, μας ανάγκασε να στηριχτούμε για τους υπολογισμούς των παραμέτρων στα αποτελέσματα των επί τόπου δοκιμών. Σκοπός της εργασίας αυτής είναι να παρουσιάσει τα υλικά των ιζημάτων, τις εδαφοτεχνικές τους παραμέτρους, τη μεθοδολογία, τους υπολογισμούς και την πρόταση θεμελίωσης για κολυμβητήριο Μεσολογγίου.Although geotechnical tests are standard and commonly used in determining the foundation type to be applied, in some cases the use ofin-situ tests are essential in order to obtain the correct values needed in the geotechnical calculations. In the case of the foundation of Mesologi Swimming-pool Center, an attempt was made to propose a foundation type, suitable from geotechnical point of view, for sediments that lie very close to the sea! The selection of the most suitable foundation type encloses the examination of several parameters. The subsoil there, consists of soft, fine grained, low plasticity materials, CL to SL with alternations of high plasticity clay layers CH. Additionally, the groundwater level is 0,8 meters under the soil surface, demonstrating constant saturation conditions. The combination of soft subsoil layers quality and the high level of groundwater leads to difficult foundation conditions in relation to immediate and secondary consolidation settlement. Geotechnical calculations and calculations of settlement were performed and the most suitable foundation type was semi-compensated mat foundation

    Efectos de los métodos de procesado y de las condiciones de almacenamiento comercial en los índices de calidad del aceite virgen extra

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    The effect of machinery groups, packing materials and light intensities was ascertained on indices of oxidative deterioration, peroxide value, and extinction coefficient K232 and K270 of extra virgin olive oil for one season of olive harvesting in an effort to simulate commercial storage conditions. It was revealed that during the storage of olive oil the peroxide value was significantly affected by the type of extraction machinery, packing material and light intensity. It is significant that oil exposed to diffused daylight and artificial light attained maximum PV in the second or third month of storage and de creased thereafter, while samples stored in the dark attained their maximum PV during the sixth month of storage. Oil samples extracted using the centrifugal type of machines and kept in glass containers in the dark had higher peroxide values than those extracted by the classic method. The rate of changes of the PV and the two indices K232 and K270 was also affected similarly by the type of machinery, packing material and light intensity.El efecto de la maquinaria, el material de envasado y la intensidad de luz fue relacionado con los índices de deterioración oxidativa, índice de peróxidos (IP) y coeficientes de extinción K232 y K270 del aceite de oliva virgen extra durante una campaña de cosecha de aceituna en un esfuerzo por simular las condiciones de almacenamiento comercial. Esto reveló que durante el almacenamiento del aceite de oliva el índice de peróxidos fue afectado significativamente por el tipo de maquinaria de extracción, el material de envasado y la intensidad de luz. Es significativo que el aceite expuesto a la luz diaria difusa y a la artificial alcanzara el máximo IP en el segundo o tercer mes de almacenamiento, decreciendo a partir de este momento, mientras que las muestras almacenadas en oscuridad no alcanzaban su máximo IP hasta el sexto mes de conservación. Las muestras de aceite extraídas con centrífuga y mantenidas en contenedores vidrio en la oscuridad alcanzaron un IP mayor que las extraídas por el sistema clásico. Las velocidades de cambio del IP y de los K232 y K270 fueron también afectadas por el tipo de maquinaria extractora empleada, el material de envasado utilizado y la intensidad de luz recibida por el aceite durante su conservación

    Differences in the Prevalence of Sarcopenia in Community-Dwelling, Nursing Home and Hospitalized Individuals. A Systematic Review and Meta-Analysis

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    © 2019, Serdi and Springer-Verlag International SAS, part of Springer Nature. Background: Sarcopenia is an age-related disease which leads to a decline in muscle mass and function and is one of the most important health issues in elderly people with a high rate and variety of adverse outcomes. Objective: The current systematic review and meta-analysis study was carried out to estimate the overall prevalence of sarcopenia in both males and females in different regions around the world and to show the major differences in its occurrence among different populations. Design: A systematic review and metaanalysis of studies published in PubMed (Medline) and Scopus. Participants: Community dwelling, nursing home and hospitalized older adults aged over 60 years. Measurements: Sarcopenia was defined by the major validated diagnostic criteria, such as the European Working Group on Sarcopenia in Older People (EWGSOP), the Asian Working Group for Sarcopenia (AWGS) and the International Working Group on Sarcopenia (IWGS). The model used was the random effect model for estimating the prevalence of sarcopenia. The sex-specific prevalence of sarcopenia as well as 95% CI (Confidence interval) were calculated using MetaXL (version 5.3). Heterogeneity assessment was carried out by subgroup analysis. Results: We included 41 studies with a total of 34955 participants. The prevalence of sarcopenia in community-dwelling individuals in the included studies were 11% (95% CI: 8–13%) in men and 9% (95% CI: 7–11%) in women. The prevalence of sarcopenia in nursing-home individuals in the included studies were 51% (95% CI: 37–66%) in men and 31% (95% CI: 22–42%) in women and in hospitalized individuals were 23% (95%, CI: 15–30%) in men and 24% (95% CI: 14–35%) in women. Conclusions: Despite the differences encountered between the studies, regarding diagnostic tools used to measure of muscle mass, different regions around the world and different populations and clinical settings, this systematic review revealed that a significant proportion of old people has sarcopenia (major in nursing homes), even in populations healthy in general. However, sarcopenia is caused by the aging progress, early diagnosis and individualized care, including physical activity and nutrition, can prevent some adverse outcomes in all populations

    Phase separation in lipid-based nanoparticles: exploring the nano-bio interface

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    This doctoral thesis is an effort to understand how lipid phase-separation induced by diacylglycerol analogues in lipid-based nanoparticles affects their in vivo behavior, leading to specific nanoparticle-protein communications and selective cell targeting. By studying how lipid composition affects morphology and this in turn affects the nano-bio interface, a comprehensive picture and prediction of nanoparticle behavior and cell selectivity is provided. More specifically, liposomes containing diacylglycerol analogues are found to phase separate and to be able to specifically target subsets of endothelial cells in zebrafish embryos. The mechanism behind this selective targeting is the result of a triglyceride lipase mediated mechanism due to phase separation and lipid composition, and is conserved in higher organisms (mice). Moreover, mRNA-based lipid nanoparticles that contain diacylglycerol analogues exhibit the same selectivity which leads to cell-specific mRNA delivery and transfection.Supramolecular & Biomaterials Chemistr

    Seasonal predictability of the 2010 Russian heat wave

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    The atmospheric blocking over eastern Europe and western Russia that prevailed during July and August of 2010 led to the development of a devastating Russian heat wave. Therefore the question of whether the event was predictable or not is highly important. The principal aim of this study is to examine the predictability of this high-impact atmospheric event on a seasonal timescale. To this end, a set of dynamical seasonal simulations have been carried out using an atmospheric global circulation model (AGCM). The impact of various model initializations on the predictability of this large-scale event and its sensitivity to the initial conditions has been also investigated. The ensemble seasonal simulations are based on a modified version of the lagged-average forecast method using different lead-time initializations of the model. The results indicated that only a few individual members reproduced the main features of the blocking system 3 months ahead. Most members missed the phase space and the propagation of the system, setting limitations in the predictability of the event

    Investigating the KNDy hypothesis in humans by co-administration of kisspeptin, neurokinin B and naltrexone in men

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    Context: A subpopulation of hypothalamic neurons co-localise three neuropeptides namely kisspeptin, neurokinin B (NKB) and dynorphin collectively termed KNDy neurons. Animal studies suggest they interact to affect pulsatile GnRH release (KNDy hypothesis); kisspeptin stimulates, NKB modulates and dynorphin (an opioid) inhibits. Objective: To investigate the KNDy hypothesis in humans, we assessed for the first time the effects of co-administration of kisspeptin-54, NKB and an opioid receptor antagonist, naltrexone on LH pulsatility (surrogate marker for GnRH pulsatility) and gonadotropin release. Design, setting and participants: Ethically approved prospective, single-blinded placebo-controlled study. Healthy male volunteers (n=5/group) attended our research facility for 8 study visits. Intervention and main outcome measure: After 1h baseline blood sampling, participants received a different intervention at each visit: oral 50mg naltrexone (NAL), 8h intravenous infusions of vehicle, 2.56nmol/kg/h NKB (NKB), 0.1nmol/kg/h kissspeptin-54 (KP) alone and in combination. Frequent blood sampling to measure plasma gonadotropins and sex steroids was conducted and LH pulsatility was determined using blinded deconvolution analysis. Results: All kisspeptin and naltrexone containing groups potently increased LH and LH pulsatility (p<0.001 vs vehicle). NKB alone did not affect gonadotropins. NKB+KP had significantly lower increases in gonadotropins compared with kisspeptin alone (p<0.01). NAL+KP was the only group to significantly increase LH pulse amplitude (p<0.001 vs vehicle). Conclusions: Our results suggest significant interactions between the KNDy neuropeptides on LH pulsatility and gonadotropin release in humans. This has important implications for improving our understanding of GnRH pulse generation in humans
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