5,582 research outputs found

    Detection of non-technical losses in smart meter data based on load curve profiling and time series analysis

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    The advent and progressive deployment of the so-called Smart Grid has unleashed a profitable portfolio of new possibilities for an efficient management of the low-voltage distribution network supported by the introduction of information and communication technologies to exploit its digitalization. Among all such possibilities this work focuses on the detection of anomalous energy consumption traces: disregarding whether they are due to malfunctioning metering equipment or fraudulent purposes, strong efforts are invested by utilities to detect such outlying events and address them to optimize the power distribution and avoid significant income costs. In this context this manuscript introduce a novel algorithmic approach for the identification of consumption outliers in Smart Grids that relies on concepts from probabilistic data mining and time series analysis. A key ingredient of the proposed technique is its ability to accommodate time irregularities – shifts and warps – in the consumption habits of the user by concentrating on the shape of the consumption rather than on its temporal properties. Simulation results over real data from a Spanish utility are presented and discussed, from where it is concluded that the proposed approach excels at detecting different outlier cases emulated on the aforementioned consumption traces.Ministerio de Energía y Competitividad under the RETOS program (OSIRIS project, grant ref. RTC-2014-1556-3)

    Influence of Light and Heavy Thresholds on SUSY Unification

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    In this paper we study and compare susy unification using two different approaches in order to take into account the effect of light particle thresholds on the evolution of gauge couplings: the step--function approximation, on the one hand, and a mass dependent procedure, which gives a more accurate description of the dependence of the results on the masses, on the other. We also include the effect of heavy thresholds, when SU(5)SU(5) is chosen as the unifying group. We find that the mass--dependent procedure excludes scenarios where all susy masses are below 1  TeV1\;TeV, and favors a value of α3(mZ)\alpha_3(m_Z) near its upper experimental bound, contrary to the results obtained with the step--function approximation. We underline the dependence of the results on the procedure chosen to deal with light thresholds.Comment: 18 pages,LAEFF-93/014,REVTEX-2.1, 5 figures not included, available upon request (include FAX number)

    A Novel Grouping Harmony Search Algorithm for Clustering Problems

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    The problem of partitioning a data set into disjoint groups or clusters of related items plays a key role in data analytics, in particular when the information retrieval becomes crucial for further data analysis. In this context, clustering approaches aim at obtaining a good parti- tion of the data based on multiple criteria. One of the most challenging aspects of clustering techniques is the inference of the optimal number of clusters. In this regard, a number of clustering methods from the literature assume that the number of clusters is known a priori and sub- sequently assign instances to clusters based on distance, density or any other criterion. This paper proposes to override any prior assumption on the number of clusters or groups in the data at hand by hybridizing the grouping encoding strategy and the Harmony Search (HS) algorithm. The resulting hybrid approach optimally infers the number of clusters by means of the tailored design of the HS operators, which estimates this important structural clustering parameter as an implicit byproduct of the instance-to-cluster mapping performed by the algorithm. Apart from inferring the optimal number of clusters, simulation results ver- ify that the proposed scheme achieves a better performance than other na ̈ıve clustering techniques in synthetic scenarios and widely known data repositories

    Effects of coherence on temporal resolution

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    Measuring small separations between two optical sources, either in space or in time, constitute an important metrological challenge as standard intensity-only measurements fail for vanishing separations. Contrarily, it has been established that appropriate coherent mode projections can appraise arbitrarily small separations with quantum-limited precision. However, the question of whether the optical coherence brings any metrological advantage to mode projections is still a point of debate. Here, we elucidate this problem by experimentally investigating the effect of varying coherence on estimating the temporal separation between two single-photon pulses. We show that, for an accurate interpretation, special attention must be paid to properly normalize the quantum Fisher information to account for the strength of the signal. Our experiment demonstrates that coherent mode projections are optimal for any degree of coherence

    Effects of coherence on temporal resolution

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    Measuring small separations between two optical sources, either in space or in time, constitute an important metrological challenge as standard intensity-only measurements fail for vanishing separations. Contrarily, it has been established that appropriate coherent mode projections can appraise arbitrarily small separations with quantum-limited precision. However, the question of whether the optical coherence brings any metrological advantage to mode projections is still a point of debate. Here, we elucidate this problem by experimentally investigating the effect of varying coherence on estimating the temporal separation between two single-photon pulses. We show that, for an accurate interpretation, special attention must be paid to properly normalize the quantum Fisher information to account for the strength of the signal. Our experiment demonstrates that coherent mode projections are optimal for any degree of coherence.Comment: 7 pages, 4 figures. To be published in Physical Review Researc

    Molecular and biochemical characterization of glucose transport in Torulaspora delbrueckii

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    Apresentação efectuada no "XIV Congresso Nacional de Bioquímica", em Vilamoura, Portugal, em Dezembro de 2004

    Sex differences in the association between dynapenic abdominal obesity and onset of disability in activities of daily living among adults aged ≥50 years: A prospective analysis of the Irish Longitudinal Study on Ageing

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    Background: Sex differences in the longitudinal relationship between dynapenic abdominal obesity, i.e., impairment in muscle strength and high waist circumference, and disability in activities of daily living have not been investigated to date. Therefore, we aimed to examine sex differences in the longitudinal association between dynapenic abdominal obesity at baseline and the onset of disability in activities of daily living during a four-year follow-up period among Irish adults aged ≥50 years. Methods: Data from Wave 1 (2009–2011) and Wave 3 (2014–2015) of the Irish Longitudinal Study on Ageing survey were analyzed. Dynapenia was defined as handgrip strength of <26 kg for men and <16 kg for women. Abdominal obesity was defined as waist circumference of >88 cm for women and >102 cm for men. Dynapenic abdominal obesity was defined as having both dynapenia and abdominal obesity. Disability was defined as having difficulty with at least one of six activities of daily living (dressing, walking, bathing, eating, getting in or out of bed, using the toilet). Multivariable logistic regression was conducted to assess associations. Results: Data on 4471 individuals aged ≥50 years and free of disability at baseline were analyzed [mean (SD) age 62.3 (8.6) years; 48.3 % males]. In the overall sample, compared to no dynapenia and no abdominal obesity, dynapenic abdominal obesity was associated with 2.15 (95%CI = 1.17–3.93) times higher odds for incident disability at 4-year follow-up. This association was significant among men (OR = 3.78; 95%CI = 1.70–8.38) but not among women (OR = 1.34; 95%CI = 0.60–2.98). Conclusions: Interventions to prevent or address dynapenic abdominal obesity may aid in the prevention of disability, especially among men

    Determination of heat wave definition temperatures in Spain at an isoclimatic level: time trend of heat wave duration and intensity across the decade 2009–2018

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    Background: In line with WHO guidelines for the implementation of public health prevention plans targeted at the impacts of high temperatures, a heat wave defnition temperature (Tthreshold) was calculated for 182 so called “isoclimatic zones” (IZ) in Spain. As the dependent variable for determining this Tthreshold, we analysed daily all-cause mortality data (ICD-10: A00-R99) for each IZ across the period 2009–2018. The independent variable used was the mean value of the maximum daily temperature of the summer months recorded at meteorological observatories in each IZ. We used Box–Jenkins models to ascertain mortality anomalies, and scatterplots to link these anomalies to the temperatures at which they occurred, thereby determining the Tthreshold for each IZ. We then calculated how many heat waves had occurred in each IZ, as well as their intensity, and analysed their time trend over this period. Results: The results showed that in 52.5% of the IZ, the percentile of the maximum temperatures series of the summer months to which Tthreshold corresponded was below the 95th percentile of the meteorological heat wave defnition in Spain: indeed, it only coincided in 30.7% of cases. The geographical distribution of these percentiles displayed great heterogeneity as a consequence of the local factors that infuence the temperature–mortality relationship. The trend in the number of heat waves analysed indicated an overall increase in Spain at a rate of 3.9 heat waves per decade, and a similar rise in mean annual intensity of 9.5 °C/decade. These time-trend values were higher than those yielded by analysing the trend in meteorological heat waves based on the 95th percentile. Conclusions: The results obtained in this study indicate the need to use a heat wave defnition based on epidemiological temperature–mortality studies, rather than on values based on meteorological percentiles. This could be minimising estimated health impacts in analyses of future impacts attributable to heat.Acknowledgements and funding The authors would like to express their gratitude for the following grants from the Carlos III Institute of Health (Instituto de Salud Carlos III/ISCIII) for the ENPY 304/20, and ENPY 436/21 projects.S

    Cyclin-Dependent Kinase Inhibitor p21 Controls Adult Neural Stem Cell Expansion by Regulating Sox2 Gene Expression

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    In the adult brain, continual neurogenesis of olfactory neurons is sustained by the existence of neural stem cells (NSCs) in the subependymal niche. Elimination of the cyclin-dependent kinase inhibitor 1A (p21) leads to premature exhaustion of the subependymal NSC pool, suggesting a relationship between cell cycle control and long-term self-renewal, but the molecular mechanisms underlying NSC maintenance by p21 remain unexplored. Here we identify a function of p21 in the direct regulation of the expression of pluripotency factor Sox2, a key regulator of the specification and maintenance of neural progenitors. We observe that p21 directly binds a Sox2 enhancer and negatively regulates Sox2 expression in NSCs. Augmented levels of Sox2 in p21 null cells induce replicative stress and a DNA damage response that leads to cell growth arrest mediated by increased levels of p19(Arf) and p53. Our results show a regulation of NSC expansion driven by a p21/Sox2/p53 axis
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