Smart Grids (SGs) are expected to be equipped with a number of smart devices able to generate vast amounts of data about the network status, becoming the key components for an efficient State ...Estimation (SE) of complex grids. To exploit their potentials, the ICT infrastructure needs to be scalable to follow the increasing amount of data flows and flexible to give the possibility to assign and re-assign grid functions and data flow control policies at runtime, possibly in a context-aware manner. In this scenario, this paper proposes and validates a Cloud-IoT-based architectural solution for SE in SG that combines cloud-capabilities and edge-computing advantages and uses virtualization technologies to decouple the handling of measurement data from the underlying physical devices. Case studies in the field of distribution networks monitoring are also analyzed, demonstrating that the proposed architecture is capable to accomplish the assigned operational tasks, while satisfying the needed quality level from both the communication and the grid perspectives with a significant degree of flexibility and adaptability with respect to state of the art solutions.
The dynamics of magnetic fields with an amplitude of several tens of megagauss, generated at both sides of a solid target irradiated with a high-intensity (~10(19) W/cm(2)) picosecond laser pulse, ...has been spatially and temporally resolved using a proton imaging technique. The amplitude of the magnetic fields is sufficiently large to have a constraining effect on the radial expansion of the plasma sheath at the target surfaces. These results, supported by numerical simulations and simple analytical modeling, may have implications for ion acceleration driven by the plasma sheath at the rear side of the target as well as for the laboratory study of self-collimated high-energy plasma jets.
Distribution systems require ad hoc estimators, distribution system state estimation (DSSE) techniques, to acquire knowledge about the system status. An incorrect evaluation of the accuracy of the ...DSSE creates decision risks in network management. The possible variations in the network parameter values and the decays of the metrological characteristics of the measurement system elements are uncertainty sources very often not considered. Considering these possible lacks of accuracy, this paper focuses on the robustness of distributed measurement systems aimed to obtain accurate DSSE results. The problem of the proper assessment of the accuracy of the DSSE results obtained through a weighted least squares (WLS) approach is faced. A method capable of including different uncertainty sources in the uncertainty estimation of the WLS approach is presented. Furthermore, this paper proposes an optimal meter placement algorithm robust with respect to possible malfunctions in measurement system components. The results obtained on a portion of an Italian distribution network, along with their accuracy, are presented and discussed.
Monitoring systems are expected to play a major role in active distribution grids, and the design of the measurement infrastructure is a critical element for an effective operation. The use of any ...available and newly installed, though heterogeneous, metering device providing more accurate and real-time measurement data offers a new paradigm for the distribution grid monitoring system. In this paper the authors study the meter placement problem for the measurement infrastructure of an active distribution network, where heterogeneous measurements provided by Phasor Measurement Units (PMUs) and other advanced measurement systems such as Smart Metering systems are used in addition to measurements that are typical of distribution networks, in particular substation measurements and a-priori knowledge. This work aims at defining a design approach for finding the optimal measurement infrastructure for an active distribution grid. The design problem is posed in terms of a stochastic optimization with the goal of bounding the overall uncertainty of the state estimation using heterogeneous measurements while minimizing the investment cost. The proposed method is also designed for computational efficiency so to cover a wide set of scenarios.
Multiple myeloma (MM) is characterized by a wide spectrum of genetic changes. Global hypomethylation of repetitive genomic sequences such as long interspersed nuclear element 1 (LINE-1), Alu and ...satellite alpha (SAT-α) sequences has been associated with chromosomal instability in cancer. Methylation status of repetitive elements in MM has never been investigated. In the present study, we used a quantitative bisulfite-polymerase chain reaction pyrosequencing method to evaluate the methylation patterns of LINE-1, Alu and SAT-α in 23 human myeloma cell lines (HMCLs) and purified bone marrow plasma cells from 53 newly diagnosed MM patients representative of different molecular subtypes, 7 plasma cell leukemias (PCLs) and 11 healthy controls. MMs showed a decrease of Alu median: 21.1 %5-methylated cytosine (%5mC), LINE-1 (70.0%5mC) and SAT-α (77.9%5mC) methylation levels compared with controls (25.2, 79.5and 89.5%5mC, respectively). Methylation levels were lower in PCLs and HMCLs compared with MMs (16.7 and 14.8%5mC for Alu, 45.5 and 42.4%5mC for LINE-1 and 33.3 and 43.3%5mC for SAT-α, respectively). Notably, LINE-1 and SAT-α methylation was significantly lower in the non-hyperdiploid versus hyperdiploid MMs (P = 0.01 and 0.02, respectively), whereas Alu and SAT-α methylation was significantly lower in MMs with t(4;14) (P = 0.02 and 0.004, respectively). Finally, we correlated methylation patterns with DNA methyltransferases (DNMTs) messenger RNA levels showing in particular a progressive and significant increase of DNMT1 expression from controls to MMs, PCLs and HMCLs (P < 0.001). Our results indicate that global hypomethylation of repetitive elements is significantly associated with tumor progression in MM and may contribute toward a more extensive stratification of the disease.
Neonicotinoids are effective insecticides used on many important arable and horticultural crops. They are nicotinic acetylcholine receptor agonists which disrupt the function of insect neurons and ...cause paralysis and death. In addition to direct mortality, there are numerous sublethal effects of low doses of neonicotinoids on bees. We hypothesize that some of these large array of effects could be a consequence of epigenetic changes in bees induced by neonicotinoids. We compared whole methylome (BS-seq) and RNA-seq libraries of the brains of buff-tailed bumblebee Bombus terrestris workers exposed to field-realistic doses of the neonicotinoid imidacloprid to libraries from control workers. We found numerous genes which show differential expression between neonicotinoid-treated bees and control bees, but no differentially methylated cytosines in any context. We found CpG methylation to be focused mainly in exons and associated with highly expressed genes. We discuss the implications of our results for future legislation.
Phasor measurement units (PMUs) are becoming one of the key issues of power network monitoring. They have to be able to perform accurate estimations of quantities of interest either under ...steady-state or transient conditions. Among all the sources which may contribute to the uncertainty introduced by PMUs, this paper analyzes the impact of the phasor estimation models on the accuracy of these devices, focuses on algorithms proposed in the literature for the estimation of dynamic phasors, and studies their performances under several different conditions.
Background: Altered patterns of gene expression mediate the effects of particulate matter (PM) on human health, but mechanisms through which PM modifies gene expression are largely undetermined. ...Objectives: We aimed at identifying short- and long-term effects of PM exposure on DNA methylation, a major genomic mechanism of gene expression control, in workers in an electric furnace steel plant with well-characterized exposure to PM with aerodynamic diameters < 10 μm (PM₁₀). Methods: We measured global genomic DNA methylation content estimated in Alu and long interspersed nuclear element-1 (LINE-1) repeated elements, and promoter DNA methylation of iNOS (inducible nitric oxide synthase), a gene suppressed by DNA methylation and induced by PM exposure in blood leukocytes. Quantitative DNA methylation analysis was performed through bisulfite PCR pyrosequencing on blood DNA obtained from 63 workers on the first day of a work week (baseline, after 2 days off work) and after 3 days of work (postexposure). Individual PM₁₀ exposure was between 73.4 and 1,220 μg/m³. Results: Global methylation content estimated in Alu and LINE-1 repeated elements did not show changes in postexposure measures compared with baseline. PM₁₀ exposure levels were negatively associated with methylation in both Alu β = -0.19 %5-methylcytosine (%5mC); p = 0.04 and LINE-1 β = -0.34 %5mC; p = 0.04, likely reflecting long-term PM₁₀ effects. iNOS promoter DNA methylation was significantly lower in postexposure blood samples compared with baseline (difference = -0.61 %5mC; p = 0.02). Conclusions: We observed changes in global and gene specific methylation that should be further characterized in future investigations on the effects of PM.
To evaluate the effects of aging and temperature on working time (WT) and setting time (ST) of several dual-cured resin cements.
WT and ST were determined with a thermo-controlled stage oscillating ...rheometer. New cement kits were used for the study. Cements were mixed according to instructions and dispensed on the oscillating stage that was preset at 22°C or 37°C. Rheologic charts were generated from the beginning of mixing until no further oscillation was detected. After initial measurements, cement kits were aged at 37°C for 12 weeks, and WT/ST was determined again at both temperatures. Five samples were read for each material and condition. Data were analyzed with repeated measures analysis of variance and a Tukey test at α=5% for each individual material.
The WT and ST of all cements were significantly affected by temperature and aging (p<0.05). In general, higher temperature accelerated WT/ST, but aging effects were material dependent. Some materials presented reduced WT/ST, whereas others showed increased WT/ST, regardless of the temperature.
The WT and ST were significantly affected by temperature variation and aging condition. Although temperature changes appeared to affect all materials similarly, aging effects were material dependent.
Different power system applications based on synchrophasors measured in different nodes of the electric grid require information about the statistical distribution of the errors introduced by the ...Phasor Measurement Units (PMUs). The performance of these applications can be significantly affected by possible incorrect assumptions. The Gaussian distribution has been historically assumed in most of the approaches, but some more recent studies suggest the possibility of considering different distributions for a more accurate modeling of the actual situation. In this paper, proper statistical tools applied to the results achieved through a high performance experimental test system are proposed to assess the statistical distribution of PMU errors under controlled steady-state conditions, thus providing a basis for defining suitable models to be used in the specific applications.
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