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The advent of distributed renewable energy sources (DRESs) has led to the progressive transformation of traditional distribution networks to active components of the power system. This transformation, however, may jeopardize the reliable grid operation due to the advent of new technical problems, such as network overloading, over-/under-voltage events, abnormal frequency deviation and dynamic instability. In this challenging scenery, the installation of a modern measuring infrastructure has created new sources of data and information that facilitate the provision of ancillary services (ASs) via measurement-based analysis. The ACTIVATE (ancillary services in active distribution networks based on monitoring and control techniques) project aims to design innovative AS solutions for power system operators. These solutions aim to tackle the technical issues emerged by the ever-increasing DRES penetration and their volatile nature. In this context, in ACTIVATE, a holistic system is proposed comprising centralized and decentralized control features to enhance the overall network performance. Additionally, a network monitoring system is designed to support a number of online and offline dynamic analysis applications by exploiting measurements obtained at the transmission, primary and secondary distribution network. This paper presents a validation of the overall system, which is performed by using simulation and power-hardware-in-the-loop results in combined transmission and distribution network models. [ABSTRACT FROM AUTHOR]

Water resources are increasingly coming under pressure specially around the Mediterranean area, leading to water scarcity and a deterioration in water quality. The use of treated wastewater represents an alternative source to enhance the demand for irrigation water. Water reuse in combination with the promotion of the use of water‐efficient technologies in industry and water‐saving irrigation techniques could lead to good qualitative and quantitative water status for surface and ground water bodies. Nevertheless, food‐borne outbreaks linked to fresh produce irrigated with partially or untreated wastewater caused by bacteria, parasites and enteropathogenic viruses have been widely reported. In the absence of solid scientific understanding of the actual risks involved, consumers are likely less receptive to buy leafy greens irrigated with treated wastewater, also known as reclaimed water. In this study, we aimed to assess the microbiological risks of leafy green vegetables irrigated with treated wastewater in Spain using Norovirus as a model organism to facilitate the development of risk management strategies. A conceptual exposure model was designed to describe the virus fate and transport from the Wastewater treatment plant (WWTP) secondary effluent to the consumers' fork. This study is an example of the use of reclaimed water for irrigation of commercial fields producing leafy greens in the south‐east of Spain and tries to assess potential microbiological risks to the consumers by establishing their safety. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for electricity, the advent of microgrids and the increasing penetration of distributed generators has renewed the interest in dynamic equivalencing, due to to its importance on power system analysis and control applications. This paper introduces a robust measurement-based framework for the online derivation of dynamic equivalent models. First, events/disturbances suitable for the derivation of dynamic equivalent models are automatically detected. Next, signal processing techniques are applied to recover missing samples and to remove noisy components from measured data. To exclude unnecessary post-disturbance data, a fine-tuning technique of the signal window length is also proposed as a supplementary offline process. Finally, model parameters are estimated using nonlinear least-squares optimization. The performance of the proposed methodology is tested using artificially created signals, simulation results obtained from a modified benchmark distribution grid and measurements acquired from a laboratory-scale active distribution network. [ABSTRACT FROM AUTHOR]

The accurate estimation of the influence of the imperfect earth on the propagation characteristics of conductors is a crucial issue in electromagnetic (EM) transient analysis. In this aspect, the frequency-dependence of the soil electrical properties should be also considered. The effects of the dispersion of soil electrical properties on EM propagation have been investigated mostly for overhead transmission lines. This article presents a detailed EM transient analysis of underground cable systems taking into consideration the frequency-dependent (FD) soil properties. A generalized earth formulation of cable earth return impedance and shunt admittance is adopted. Propagation characteristics and transient responses are calculated by using both FD soil models and constant soil properties, as well as approximate earth formulations, neglecting the influence of the imperfect earth on shunt admittances; significant differences are observed. Guidelines for the accurate evaluation of earth conduction effects on the transient performance of underground cable systems are also introduced. [ABSTRACT FROM AUTHOR]

• Using Geospatial Technologies to understand Mixed Reality better. • Utilizing the Internet of Things to communicate between Mixed Reality Environments and the Real Worlds. • Defining a novel Virtual-to-Real interaction method for Mixed Reality Interactions. • Demonstrating a case study with an application prototype, where a virtual man executes a physical task. As Mixed Reality applications penetrate people's daily activities, strong synergies with Geospatial technologies and the Internet of Things are revealed. The first is due to the significance of the spatial reference of all involved actors of a Mixed Reality environment: the end-user, the real and the virtual objects. The second is due to the ever-increasing participation of sensors controlling devices and machines always and everywhere. This paper highlights these synergies and proposes a case proving they crucially empower a Mixed Reality experience. Through this synergy, a novel interaction method for Mixed Reality Environments emerges, the "physical task execution" interaction method. An open-source application prototype was developed to support the case study where we assign a physical task to a virtual man to execute, utilising the Internet of Things in a Mixed Reality Environment. [ABSTRACT FROM AUTHOR]

Campylobacter species are one of the leading causes of foodborne disease. Poultry is a major reservoir and source of its transmission to humans. The aim of this study was to estimate the prevalence and antimicrobial resistance of Campylobacter spp. isolated from chicken carcasses, the environment, and processing equipment of a poultry slaughterhouse in Greece, to identify the dominant Campylobacter species and to determine if there are clonal relationships among the isolates. Fifty poultry samples and 25 environmental samples were examined using microbial cultures and PCR. Fortynine of 50 poultry samples (98%) were found to be positive for Campylobacter spp. The environment of the slaughterhouse was also found to be signifi cantly contaminated with Campylobacter spp. Thirty-seven isolates were found to be susceptible to all antimicrobials tested (56.1%) and 29 isolates showed resistance to at least two of the antimicrobials tested (43.9%). We observed 24 different PFGE-types among the 53 isolates with 14 of them isolated only once, while fi ve PFGE-types were represented by two isolates. The remaining 29 isolates were represented by fi ve PFGE-types each consisting of three to 12 isolates. Regarding the relationship of the PFGE types and corresponding resistance profi les, all strains of each PFGE-type shared the same antimicrobial resistance profi le. This study reports evidence for Campylobacter spp. cross-contamination among broiler carcasses in a Greek slaughterhouse. [ABSTRACT FROM AUTHOR]

Aggregated equivalent models for the dynamic analysis of active distribution networks (ADNs) can be efficiently developed using dynamic responses recorded through field measurements. However, equivalent model parameters are highly affected from the time-varying composition of power system loads and the stochastic behavior of distributed generators. Thus, equivalent models, developed through in situ measurements, are valid only for the operating conditions from which they have been derived. To overcome this issue, in this paper, a new method is proposed for the derivation of generic aggregated dynamic equivalent models, i.e., for equivalent models that can be used for the dynamic analysis of a wide range of network conditions. The method incorporates clustering and artificial neural network techniques to derive robust sets of parameters for a variable-order dynamic equivalent model. The effectiveness of the proposed method is evaluated using measurements recorded on a laboratory-scale ADN, while its performance is compared with a conventional technique. The corresponding results reveal the applicability of the proposed approach for the analysis and simulation of a wide range of distinct network conditions. [ABSTRACT FROM AUTHOR]

Abstract Staphylococcus aureus is an important cause of food intoxication, whereas methicillin-resistant S. aureus (MRSA) constitutes a serious public-health concern due to its ability to colonize and infect humans and animals. S. aureus and MRSA have often been isolated from milk and dairy products. The objectives of this study were to estimate the prevalence and the antimicrobial resistance of S. aureus and MRSA in four Greek dairy industries, to identify virulence factors of MRSA isolates and to describe their genetic diversity, in order to identify possible epidemiological links and evaluate the risk of MRSA dissemination to the community. S. aureus was isolated from 67 out of 305 (22.0%) dairy industry samples (bulk-tank milk, dairy products, employee nasal swabs and equipment/surface swabs). Almost all (99%) of the 227 corresponding S. aureus isolates (approximately 4 isolates per positive sample) were resistant to at least one antimicrobial and 22% were multi-drug resistant (MDR). MRSA were isolated from 11 different samples (3.6%) originating from three of the dairy plants. All MRSA isolates were capable of forming biofilms, while staphylococcal enterotoxin (SE) genes were detected in 91% of the MRSA isolates, with sec being the most frequent. All of the MRSA isolates harbored the mec A gene but the mec C and Pandon-Valentine leucocidin (PVL) genes were not detected. Pulse-Field Gel Electrophoresis (PFGE) analysis showed genetic diversity among the MRSA isolates and indicated clonal circulation in one of the dairy plants. Seven spa types were identified among the MRSA isolates with the most prevalent (t065) isolated only in one dairy plant. Certain spa types (t065, t337 and t3536) were isolated for the first time in Greece. The presence of MDR, biofilm-forming and enterotoxigenic MRSA strains in dairy plant facilities may lead to their dissemination to the community, but also to staphylococcal food poisoning, when conditions are favorable. The study's findings highlight the need for continuous monitoring of the dairy production chain, the need for re-evaluating the implemented cleaning and sanitizing processes and the adoption of preventive strategies in order to minimize public-health risks. Highlights • Of 305 samples tested, 22.0% were S. aureus -positive & 3.6% were MRSA-positive. • Most MRSA isolates belonged to spa type t065. • spa types t065, t337 and t3536 were isolated for the first time in Greece. • Almost all MRSA isolates harbored SE-genes; sec being most frequent. • All MRSA isolates were capable to form biofilm. [ABSTRACT FROM AUTHOR]

In this paper, two discretization techniques are combined to present a coupled electro-thermal model for the transient analysis of gas-insulated transmission lines (GILs). The analysis of the thermal problem is based on the volume-element-method, representing heat transfer equations on a 2-D axisymmetric GIL model and determining temperature distribution over space and time. For the electrical formulation, the finite-difference time-domain method is adopted considering constant parameters calculated at the frequency of interest. The coupled electro-thermal problem in the case of transient conditions is solved by means of a bidirectional procedure. A set of test cases is imposed on the electric part, and transient analysis is conducted while considering the line coupled electro-thermal performance. [ABSTRACT FROM AUTHOR]

This paper introduces a two-step methodology for online identification of the participation of generators in power system oscillatory modes, based on measured responses. The dominant modes in generator measured responses are initially identified using a mode identification technique and then introduced, in the next step, as input into a clustering algorithm. Critical groups of generators that exhibit poorly or negatively damped oscillations are identified, in order to enable corrective control actions and stabilize the system. The uncertainties associated with the operation of modern power systems with renewable energy sources (RESs) are investigated as well as the impact of the dynamic behavior of power electronic interfaced RESs. [ABSTRACT FROM AUTHOR]

Mode identification from post-disturbance “ringdown” responses can provide vital information concerning the dynamic performance and the stability margins of power systems. Therefore, several measurement-based identification techniques have been proposed in the literature to analyze ringdown responses of transmission systems and provide close to real-time estimation of the modal content. However, the applicability of these methods has not been thoroughly investigated for the analysis of active distribution networks (ADNs). Scope of this paper is to evaluate the applicability and the performance of eight measurement-based system identification techniques for the modal analysis of ADNs. The examined methods are used to identify the dominant oscillatory modes contained in ringdown responses of different types of signals. The Monte Carlo method is applied to investigate the influence of several parameters on the accuracy and efficiency of the identification procedure, while laboratory measurements are used to further demonstrate the accuracy of the examined methods. Practical issues encountered in the application of the identification techniques for the analysis of ADNs are discussed and potential solutions are proposed. Results reveal that although most of the examined techniques perform satisfactorily enough and thus can be readily employed for the modal analysis of ADNs, the Vector Fitting and the Hybrid FD/TD seem to be the most effective methods in terms of accuracy, robustness and computational efficiency. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the production chain of dairy products. Of 367 tested samples (36 bulk tank milk (BTM), 19 dairy products, 72 human, 185 animal, 55 equipment), 212 (57.8%) were found positive for S. aureus . Almost all isolates (99.6%) were resistant to at least one antimicrobial and 13.3% were multi-drug resistant (MDR), exhibiting resistance to three or more antibiotic classes. Eleven samples (3%) were found contaminated by MRSA carrying the mec A gene. None of the MRSA isolates carried the mec C or the Pandon-Valentine leucocidin (PVL) genes. Four spa types were identified among the MRSA isolates: t127, t3586, t1773, t4038, with t127 being the most prevalent (7 out of 11). Two of them, t3586 and t1773, were isolated for the first time in Greece. Furthermore, Pulse-Field Gel Electrophoresis (PFGE) analysis indicated clonal circulation through the dairy production chain. The presence of MDR S. aureus , and especially MRSA, in animals and dairy products represents a potential threat for the spread of this pathogen in the community. The results indicated that human, animal and environmental sources could be involved in the contamination of dairy products along their production chain and therefore further investigation of contamination sources is needed to control the dispersion of MRSA in the community. [ABSTRACT FROM AUTHOR]

Digital Elevation Models (DEMs), in combination with high quality raster graphics provide realistic three-dimensional (3D) representations of the globe (virtual globe) and amazing navigation experience over the terrain through earth browsers. In addition, the adoption of interoperable geospatial mark-up languages (e.g. KML) and open programming libraries (Javascript) makes it also possible to create 3D spatial objects and convey on them the sensation of any type of texture by utilizing open 3D representation models (e.g. Collada). One step beyond, by employing WebGL frameworks (e.g. Cesium.js, three.js) animation and motion effects are attributed on 3D models. However, major GIS-based functionalities in combination with all the above mentioned visualization capabilities such as for example animation effects on selected areas of the terrain texture (e.g. sea waves) as well as motion effects on 3D objects moving in dynamically defined georeferenced terrain paths (e.g. the motion of an animal over a hill, or of a big fish in an ocean etc.) are not widely supported at least by open geospatial applications or development frameworks. Towards this we developed and made available to the research community, an open geospatial software application prototype that provides high level capabilities for dynamically creating user defined virtual geospatial worlds populated by selected animated and moving 3D models on user specified locations, paths and areas. At the same time, the generated code may enhance existing open visualization frameworks and programming libraries dealing with 3D simulations, with the geospatial aspect of a virtual world. [ABSTRACT FROM AUTHOR]

Accurate load modeling is essential for power system stability analysis and control. This topic has regained interest, due to the high penetration of new types of loads and the increased availability of measurements in extended power grids. In this paper, an aggregated load model based on measurement data is formulated for dynamic simulations of large power systems. The proposed model employs variable-order transfer functions, enabling the accurate simulation of complex load dynamics. A complete methodology for the automatic derivation of the minimum-required model order is proposed with the model parameters calculated via a robust multisignal identification procedure. For this purpose, the vector fitting method is introduced as a technique for measurement-based load modeling. Several simulations are performed using the NEPLAN software to investigate the accuracy and the generalization capabilities of the proposed model. The model performance is thoroughly compared with other conventional load models, also using measurements recorded on a laboratory-scale microgrid. [ABSTRACT FROM PUBLISHER]

Power-line communication (PLC) is gaining a renewed interest, due to the smart grid (SG) emerging communication requirements. Among other communication technologies, PLC is a very efficient and feasible solution, especially for the extended SG distribution networks. However, it is very challenging to consider both the medium- and low-voltage parts of the distribution network as a whole communication medium, due to the attenuating effects of distribution transformers, limiting PLC applicability. In this paper, data transmission through distribution transformers is investigated by means of multiple-input multiple-output (MIMO) narrowband power-line communication (NB-PLC) system, utilizing orthogonal frequency-division multiplexing (OFDM) technology. Multi-conductor distribution line and measurement-based transformer models are developed to characterize the MV–LV PLC channel. In addition, OFDM signal processing techniques are applied to enhance the achievable data rates. The transmit power budget and bit allocation across the OFDM sub-channels of the spatial beams are optimized to maximize the data rate through the distribution transformer. The achievable data rates are calculated and systematically analysed for different scenarios to investigate the effects of the distribution lines, connected loads, noise models, etc. Results reveal the superiority of the proposed MIMO design against the traditional SISO systems. In addition, the possibility for an extensive and reliable application of MV–LV PLC communications through distribution transformers is shown. [ABSTRACT FROM AUTHOR]

Power engineers are expected to play a pivotal role in transforming buildings into smart and energy-efficient structures, which is necessary since buildings are responsible for a considerable amount of the total energy consumption. To fulfil this role, a holistic approach in education is required, tackling subjects traditionally related to other engineering disciplines. In this context, USE Efficiency is an inter-institutional and interdisciplinary educational programme implemented in nine European Universities targeting energy efficiency in buildings. The educational programme effectively links professors, students, engineers and industry experts, creating a unique learning environment. The scope of the paper is to present the methodology and the general framework followed in the USE Efficiency programme. The proposed methodology can be adopted for the design and implementation of educational programmes on energy efficiency and sustainable development in higher education. End-of-course survey results showed positive feedback from the participating students, indicating the success of the programme. [ABSTRACT FROM AUTHOR]

While the postsynaptic density of excitatory synapses is known to encompass a highly complex molecular machinery, the equivalent organizational structure of inhibitory synapses has long remained largely undefined. In recent years, however, substantial progress has been made towards identifying the full complement of organizational proteins present at inhibitory synapses, including submembranous scaffolds, intracellular signaling proteins, transsynaptic adhesion proteins, and secreted factors. Here, we summarize these findings and discuss future challenges in assigning synapse-specific functions to the newly discovered catalog of proteins, an endeavor that will depend heavily on newly developed technologies such as proximity biotinylation. Further advances are made all the more essential by growing evidence that links inhibitory synapses to psychiatric and neurological disorders. [ABSTRACT FROM AUTHOR]

All the Salmonella enterica ser. Infantis strains isolated under official control programs in Greece during a four year period were studied, 23 of human origin, 16 from food animals and one from food. Molecular analyses (PFGE) in combination with antimicrobial susceptibility testing were used to study whether the occurrence S. Infantis in Greece resulted from different biotypes or a successful spread of one clone. Low rates of antimicrobial resistance were observed, except for streptomycin among human isolates (48%), indicating that selective pressure due to consumption of antimicrobials has not resulted the spread of dominant clones. Pulsed Field Gel Electrophoresis revealed 31 Xba I distinct pulsotypes among the 40 strains with 60% overall similarity reflecting diversity. Four main clusters were constructed, using an 85% cut off value, clusters A, B, C and D consisting of 14, 6, 8 and 8 isolates respectively. Point source of transmission was not hypothesized as multiple reservoirs of the serovar seem to be present in Greece during the study period. [ABSTRACT FROM AUTHOR]

Background: Although renal fibrosis and inflammation have shown to be involved in the pathophysiology of obstructive nephropathies, molecular mechanisms underlying evolution of these processes remain undetermined. In an attempt towards improved understanding of obstructive nephropathy and improved translatability of the results to clinical practice we have developed a systems biology approach combining omics data of both human and mouse obstructive nephropathy. Results: We have studied in parallel the urinary miRNome of infants with ureteropelvic junction obstruction and the kidney tissue miRNome and transcriptome of the corresponding neonatal partial unilateral ureteral obstruction (UUO) mouse model. Several hundreds of miRNAs and mRNAs displayed changed abundance during disease. Combination of miRNAs in both species and associated mRNAs let to the prioritization of five miRNAs and 35 mRNAs associated to disease. In vitro and in vivo validation identified consistent dysregulation of let-7a-5p and miR-29-3p and new potential targets, E3 ubiquitin-protein ligase (DTX4) and neuron navigator 1 (NAV1), potentially involved in fibrotic processes, in obstructive nephropathy in both human and mice that would not be identified otherwise. Conclusions: Our study is the first to correlate a mouse model of neonatal partial UUO with human UPJ obstruction in a comprehensive systems biology analysis. Our data revealed let-7a and miR-29b as molecules potentially involved in the development of fibrosis in UPJ obstruction via the control of DTX4 in both man and mice that would not be identified otherwise. [ABSTRACT FROM AUTHOR]

The formation of neuronal synapses and the dynamic regulation of their efficacy depend on the proper assembly of the postsynaptic neurotransmitter receptor apparatus. Receptor recruitment to inhibitory GABAergic postsynapses requires the scaffold protein gephyrin and the guanine nucleotide exchange factor collybistin (Cb). In vitro, the pleckstrin homology domain of Cb binds phosphoinositides, specifically phosphatidylinositol 3-phosphate (PI3P). However, whether PI3P is required for inhibitory postsynapse formation is currently unknown. Here, we investigated the role of PI3P at developing GABAergic postsynapses by using a membrane-permeant PI3P derivative, timelapse confocal imaging, electrophysiology, as well as knockdown and overexpression of PI3P-metabolizing enzymes. Our results provide the first in cellula evidence that PI3P located at early/sorting endosomes regulates the postsynaptic clustering of gephyrin and GABAA receptors and the strength of inhibitory, but not excitatory, postsynapses in cultured hippocampal neurons. In human embryonic kidney 293 cells, stimulation of gephyrin cluster formation by PI3P depends on Cb. We therefore conclude that the endosomal pool of PI3P, generated by the class III phosphatidylinositol 3-kinase, is important for the Cbmediated recruitment of gephyrin and GABAA receptors to developing inhibitory postsynapses and thus the formation of postsynaptic membrane specializations. [ABSTRACT FROM AUTHOR]

This short communication introduces vector fitting for mode estimation from ringdown responses of power systems. The performance of the method is evaluated for different power system models and is found to be very accurate. [ABSTRACT FROM AUTHOR]

Online recorded responses can be used for aggregate dynamic load modelling, taking advantage of the advent of smart grids and the growing installation of phasor measurement units. Although several measurement-based dynamic load models have been proposed in the literature, still most network utilities and system operators take advantage of well-known formulations such as the polynomial and the exponential recovery models. However, these types of load models are only valid for a specific range of operating conditions, thus minimizing their applicability and efficiency. This is mainly due to the fact that the model parameter estimation procedure relies on iterative processes. To this extent, the specific scope of this paper is to present a comprehensive identification procedure for evaluating load models under different loading conditions and further to propose two generic modelling approaches that can be used to derive robust load models that are suitable for dynamic simulations over a wide range. Towards achieving the scope of this paper, Monte Carlo simulations are used to train and validate the data of the loading conditions. Finally, several simulations are performed within the DIgSILENT PowerFactory software to assess the accuracy of the proposed models. [ABSTRACT FROM AUTHOR]

In this paper, a multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) system is proposed for narrowband power-line communication (NB-PLC) applications in medium-voltage (MV) networks. Multi-conductor transmission line theory is used for accurate MV NB-PLC channel characterization and evaluation of the spatial correlation between the phase conductors. By optimizing the indices of the active OFDM sub-channels, the bit allocation across them, and the transmit power allocation across the spatial beams, the proposed MIMO-OFDM design can achieve significant data rate gains over single-input single-output OFDM transmission. The achievable MIMO-OFDM data rates are evaluated for an MV overhead network with different lengths, coupler impedances and branches, showing that the proposed MIMO-OFDM design is an efficient implementation of NB-PLC technology in MV smart distribution grids. [ABSTRACT FROM AUTHOR]

System identification methods have been widely used for the study of low frequency electromechanical oscillations and the development of low order dynamic models. This paper introduces a hybrid frequency/time-domain approach to estimate the dominant modes contained in ringdown responses of power systems. Practical issues and solutions encountered in the application of the hybrid method are discussed. The performance of the proposed technique is evaluated by applying the Monte Carlo method to synthetic signals and simulated responses from a large-scale power system, as well as to measurements recorded in a microgrid laboratory test facility. Results in all cases proved to be very accurate, verifying the robustness of the proposed method. [ABSTRACT FROM PUBLISHER]

In this paper, a multi-signal identification technique is developed to estimate oscillatory modes contained in power system responses. The proposed technique utilizes least-squares optimization to analyze simultaneously several system measurements and determine close-to-real-time the modal parameters of the examined power system. The Monte Carlo method is applied to synthetic signals to thoroughly quantify the impact of several parameters on the accuracy of the proposed technique and comparisons with conventional identification techniques are performed. The accuracy of the proposed method is also validated using simulated responses obtained from a combined transmission–distribution network. Finally, the scalability of the proposed technique is demonstrated using power hardware-in-the-loop experiments. • A mode identification multi-signal least-squares-based technique is proposed. • It is evaluated by using synthetic signals, simulations and data from PHIL tests. • The proposed technique is suitable for close to real-time applications. • It can efficiently analyze responses at different sampling rates. • It applies in cases of temporary communication failures and corrupted data streams. [ABSTRACT FROM AUTHOR]

This letter delivers a method to extend the use of the exponential recovery model (ERM) for the dynamic simulation of active distribution networks (ADNs). The conventional ERM uses exponential functions to describe the steady-state and transient characteristics of the grid, failing to replicate reverse power flow phenomena which may occur in modern ADNs during or after voltage disturbances. To solve this issue a new formulation employing polynomial functions instead of the original exponential is proposed. [ABSTRACT FROM AUTHOR]

In the recent decades, the evolution of omics technologies has led to advances in all biological fields, creating a demand for effective storage, management and exchange of rapidly generated data and research discoveries. To address this need, the development of databases of experimental outputs has become a common part of scientific practice in order to serve as knowledge sources and data-sharing platforms, providing information about genes, transcripts, proteins or metabolites. In this review, we present omics databases available currently, with a special focus on their application in kidney research and possibly in clinical practice. Databases are divided into two categories: general databases with a broad information scope and kidney-specific databases distinctively concentrated on kidney pathologies. In research, databases can be used as a rich source of information about pathophysiological mechanisms and molecular targets. In the future, databases will support clinicians with their decisions, providing better and faster diagnoses and setting the direction towards more preventive, personalized medicine. We also provide a test case demonstrating the potential of biological databases in comparing multi-omics datasets and generating new hypotheses to answer a critical and common diagnostic problem in nephrology practice. In the future, employment of databases combined with data integration and data mining should provide powerful insights into unlocking the mysteries of kidney disease, leading to a potential impact on pharmacological intervention and therapeutic disease management. [ABSTRACT FROM AUTHOR]

In this paper numerical improvements are proposed to enhance the accuracy and efficiency of frequency-domain transient transmission line modeling. The adopted procedure is based on a robust eigenvector tracking algorithm and an accurate shape-preserving interpolation routine, formulating the highly resonant nodal admittance matrix from a minimal number of frequency data. The proposed method is integrated with the numerical Laplace transform and its performance is demonstrated in a configuration, consisting of an underground cable and an overhead line. Results are validated with the corresponding obtained from a frequency-domain model with regular sampling, revealing the high accuracy of the proposed formulation. The computational efficiency of the proposed numerical improvements is highlighted by comparisons of the execution times in cases of high sampling rates. [ABSTRACT FROM AUTHOR]

This study presents a new, generalised method for the calculation of resonance frequencies (RFs) in transmission line (TL) responses. The proposed method calculates the RF of any propagation mode and is applicable to all types of TL configurations, taking also into account the effect of the source and load impedances as well as of possible transpositions or cross‐bondings. The results are validated with the corresponding results obtained from frequency‐domain transient simulations and laboratory measurements, whereas simple theoretical formulas for both overhead lines and underground cables are also investigated, revealing their limited accuracy. Practical cases of engineering interest are demonstrated, where the required single or multiple RFs are accurately calculated by the proposed method. Finally, the performance of the presented methodology is thoroughly examined incorporating two diagonalisation approaches for the calculation of the modal propagation velocities. [ABSTRACT FROM AUTHOR]

Modeling of power distribution transformers in the high-frequency range is of crucial importance in cases such as using power-line communication technology or investigating transient overvoltages at the transformer low-voltage side. This paper presents a simple black-box modeling methodology for distribution transformers using transfer functions defined by the recorded voltage ratios at the transformer terminals. The model parameters are estimated using an optimization method that minimizes the error between the measured and the calculated data. A significant advantage of the proposed methodology is the use of conventional instruments in conducting the measurements rather than high-precision and expensive equipment. The accuracy of the developed model is verified by its implementation in both frequency- and time-domain simulations. [ABSTRACT FROM AUTHOR]

Signaling at nerve cell synapses is a key determinant of proper brain function, and synaptic defects-or synaptopathies-are at the basis of many neurological and psychiatric disorders. In key areas of the mammalian brain, such as the hippocampus or the basolateral amygdala, the clustering of the scaffolding protein Gephyrin and of γ-aminobutyric acid type A receptors at inhibitory neuronal synapses is critically dependent upon the brainspecific guanine nucleotide exchange factor Collybistin (Cb). Accordingly, it was discovered recently that an R290H missense mutation in the diffuse B-cell lymphoma homology domain of Cb, which carries the guanine nucleotide exchange factor activity, leads to epilepsy and intellectual disability in human patients. In the present study, we determined the mechanism by which the CbR290H mutation perturbs inhibitory synapse formation and causes brain dysfunction. Based on a combination of biochemical, cell biological, and molecular dynamics simulation approaches, we demonstrate that the R290H mutation alters the strength of intramolecular interactions between the diffuse B-cell lymphoma homology domain and the pleckstrin homology domain of Cb. This defect reduces the phosphatidylinositol 3-phosphate binding affinity of Cb, which limits its normal synaptogenic activity. Our data indicate that impairment of the membrane lipid binding activity of Cb and a consequent defect in inhibitory synapse maturation represent a likely molecular pathomechanism of epilepsy and mental retardation in humans. [ABSTRACT FROM AUTHOR]

The dynamic performance of microgrids is of crucial importance, because of the increased complexity introduced by the combined effect of inverter interface and rotating distributed generation. This study presents a methodology for the investigation of the dynamic behaviour of microgrids based on measurements using Prony analysis and state‐space black‐box modelling techniques. Both methods are compared and evaluated using real operating conditions data obtained by a laboratory microgrid system. The recorded responses and the calculated system eigenvalues are used to analyse the system dynamics and interactions among the distributed generation units. The proposed methodology can be applied to any real‐world microgrid configuration, taking advantage of the future smart grid technologies and features. [ABSTRACT FROM AUTHOR]

This paper presents a new method for the calculation of smooth frequency-dependent transmission-line (TL) transformation matrices. The proposed method, based on the Levenberg–Marquardt algorithm, solves an equivalent real-valued approach of the generalized complex eigenproblem. The implemented formulation incorporates a robust convergence criterion and is applicable to all TL configurations, due to the included numerically well-defined computational scheme. Smooth modal transformation matrices are calculated for overhead and underground TL configurations under different representations of the imperfect earth. Results are compared and validated with the corresponding results obtained from the Newton–Raphson and the sequential quadratic programming methods, revealing the accuracy, efficiency, and robustness of the proposed formulation, even in cases where the other methods fail. [ABSTRACT FROM AUTHOR]

A dynamic equivalent black‐box model, based on Prony analysis is presented. The proposed model is suitable for dynamic studies of microgrids, considering changes in the active and reactive powers, bus voltages, currents and frequency. The developed model is evaluated using simulation results obtained from a medium‐voltage microgrid and test measurements recorded in a low‐voltage microgrid laboratory test facility. Results from the proposed model are in good agreement with the corresponding responses obtained from both simulations and laboratory tests. The examined microgrid configurations include rotating machines and inverter interfaced units implementing different control strategies, thus verifying the robustness of the proposed model. [ABSTRACT FROM AUTHOR]

Highlights: [•] We propose a methodology for the investigation of buildings’ electrical consumption through clustering techniques. [•] For this purpose the performance of different clustering algorithms are evaluated. [•] Detailed parameter optimization guidelines are proposed for the SOM algorithm. [•] We use as a test case a set of buildings of different utilization in a university campus. [•] The methodology is a useful tool for the load profiling analysis. [Copyright &y& Elsevier]

Highlights: [•] Introduction of a model simulating a PLC channel in the narrowband frequency range. [•] Model validation using test measurements by a medium voltage single-core cable. [•] The common and differential modes of propagation are examined. [•] Experimental and simulation results in very good agreement validating the model. [•] Investigation of the influence of different parameters on the transmitted signal. [ABSTRACT FROM AUTHOR]

Non-intrusive load monitoring (NILM) is a topic that lately attracts both the academic and the industrial interest. NILM is used to reveal useful information regarding the consumption breakdown on appliance or activity level, thus can be a key solution to unlock various smart-home services and opportunities. To that end, deep learning has arisen as a prominent solution. Although most of the known solutions so far focus on a predefined number of home appliances, this paper proposes a multi-class NILM system which can detect in real-time any number of appliances and can be efficiently embedded into simple microprocessors. The key feature for the identification of the appliances is the processing of measured turn-on active power transient responses sampled at 100 Hz. The NILM system includes three stages; adaptive thresholding event detection method, convolutional neural network and k-nearest neighbors classifier. For future extensions, it is capable to automatically identify new appliances; thus, no retraining and additional modeling is required. [ABSTRACT FROM AUTHOR]

Single conductor cables are widely used in several types of installations over the last years, including the interconnection of wind parks to the power grid. Owing to the complexity of cable installations each configuration must be treated individually, regarding the use of sheath cross‐bonding, the influence of grounding resistances and the use of sheath voltage limiters. In this study, a systematic investigation of the performance of a long‐medium‐voltage cable configuration is presented. Sheath voltages and currents are calculated during steady‐state and short‐circuit conditions for varying sheath arrangements using the ATP/EMTP software. Results are validated by field measurements. The analysis is also extended to include the investigation of overvoltages in the installation, during slow and fast transients, according to the basic insulation level for the cable system. [ABSTRACT FROM AUTHOR]

Narrowband power-line communication (PLC) over distribution networks is gaining the attention of researchers, as a communication medium in future power grids. This paper investigates the application of narrowband PLC in smart distribution grids, starting from a historical overview on the accomplished technological progress and continuing with a comparison of the advantages and drawbacks of PLC technology to other smart-grid communication solutions. The analysis shows that narrowband PLC applications are best suitable for medium-voltage (MV) networks, due to the vast and complex geographical extent. The channel and topological characteristics of MV distribution networks are examined for different operational states and configurations, since they are important for the optimal design and implementation of the PLC infrastructure. The analysis is also extended to an existing overhead MV distribution network with distributed-generation units. The obtained results and the proposed methodology are useful and comprehensive tools for the efficient implementation of PLC technology in future smart grids. [ABSTRACT FROM PUBLISHER]

In electromagnetic transient analysis, one major issue is the influence of the imperfect earth on the propagation characteristics of transmission line conductors. Extensive research has been published for overhead lines, whereas the corresponding literature for underground cables is significantly less. Recently, new expressions for the calculation of the ground impedance and admittance have been proposed for the homogeneous and the stratified earth case. However, most transient simulation programs still use approximate earth representations. Scope of this study is to compare the proposed formulation with the corresponding approximations, in order to introduce a frequency limit for the use of the approximate earth models, sas well as criteria that dictate the use of a stratified earth model. The resulting propagation characteristics are used in transient calculations, in order to validate the effect of the differences by the various approaches and the need to include a more accurate model in the simulation of underground cable transients. [ABSTRACT FROM AUTHOR]

The increasing penetration of distributed renewable energy sources drastically alters the dynamic characteristics of distribution networks (DNs). Therefore, several equivalent models have been recently proposed, to analyze more accurately the complex behavior of modern DNs. However, relatively simple models are still commonly used in practice for dynamic power system studies. In addition, dynamic equivalent models for DNs are sensitive to different operating conditions and there is lack of systematic understanding of their performance. Scope of this paper is to propose a methodology for identifying the applicability range in terms of accuracy and generalization capability of several conventional and newly developed equivalent models for the dynamic analysis of modern DNs. A set of metrics is used for the modelling accuracy assessment and a sensitivity analysis framework is introduced to fully quantify the generalization capabilities of DN equivalent models. Based on the above, guidelines and recommendations for the development of robust equivalent models for DN analysis are proposed. [ABSTRACT FROM AUTHOR]

Abstract: A general formulation for the determination of the influence of imperfect earth on overhead transmission line impedances and admittances is presented in this paper. The resulting model can be used in the simulation of electromagnetic transients in cases of two-layer earth over a wide frequency range, covering most fast transient phenomena of power engineering interest. The propagation characteristics of an overhead transmission line over homogeneous and two-layer earth are investigated using the proposed model. A systematic comparison of the proposed model with other approaches is also presented and the differences due to earth stratification are reported. Finally, the transmission line parameters calculated by the proposed formulation are used in the simulation of fast transient surges in a transmission line excited by double exponential sources. [Copyright &y& Elsevier]

A general formulation for the calculation of the influence of the earth return path on the impedances and the admittances of underground multiconductor power cable arrangements is presented in this paper. The expressions for the self and mutual earth correction terms are derived by a rigorous solution of the electromagnetic-field equations. The involved semiinfinite integrals are calculated by using a suitable numerical integration technique. The propagation characteristics of a single insulated conductor and of a typical three-phase single-core cable arrangement are investigated and are compared to the corresponding ones obtained by other approaches. Finally, the cable parameters calculated by the proposed method are used in a simulation of a fast transient in a three-phase single-core cable. [ABSTRACT FROM AUTHOR]

Abstract: Collybistin (Cb), a brain-specific guanine nucleotide exchange factor, has been shown to be essential for the gephyrin-dependent clustering of a specific set of GABAA receptors at inhibitory postsynaptic sites. Here, we examined whether the lack of Cb affects synaptic properties and neuronal activity in the intact hippocampus by monitoring network activity in the dentate gyrus of Cb-deficient mice after perforant-path stimulation in vivo. We found a decreased threshold for evoked population spikes of granule cells, indicating their increased excitability. Paired-pulse inhibition of the population spike, a measure for somatic GABAergic network inhibition, was enhanced. Mutant mice exhibited steeper slopes of field excitatory postsynaptic potentials, consistent with a reduced dendritic inhibition. In addition, the induction of long-term potentiation (LTP) was reduced. In line with these functional changes, the number of postsynaptic gephyrin and GABAA receptor clusters in the Cb-deficient dentate gyrus was significantly decreased. In conclusion, our data provide the first evidence that Cb-deficiency leads to significant changes of GABAergic inhibition, network excitability and synaptic plasticity in vivo. [Copyright &y& Elsevier]

The influence of stratified earth on the wave propagation characteristics of overhead conductors is analyzed, using a generalized two-layer earth model of varying electromagnetic characteristics. A systematic comparison to simpler stratified earth models is presented, showing the differences in the propagation characteristics. [ABSTRACT FROM AUTHOR]

Abstract: Collybistin (Cb) is a brain-specific guanine nucleotide exchange factor, which interacts with the inhibitory receptor anchoring protein gephyrin. In the hippocampus of constitutively Cb-deficient adult mice, gephyrin and gephyrin-dependent GABAA receptors (GABAARs) are lost from postsynaptic sites. Here, we used a Cre–loxP system to inactivate the Cb gene in the forebrain at different developmental stages. Deletion of Cb during embryonic development prevented gephyrin clustering during synaptogenesis and caused an accumulation of gephyrin aggregates in the cell body of CA1 pyramidal neurons. Inactivation of the Cb gene during the third postnatal week resulted in a protracted loss of postsynaptic gephyrin clusters and the appearance of cytoplasmic gephyrin aggregates. These changes in gephyrin distribution were accompanied by a similar reduction in synaptically localized GABAAR γ2-subunit immunoreactivity. Our data show that Cb is required for both the initial localization and maintenance of gephyrin and gephyrin-dependent GABAARs at inhibitory postsynaptic membrane specializations in the hippocampus. [Copyright &y& Elsevier]

Power-line communications over the low-voltage networks is gaining the attention of researchers in both broadband and narrowband application areas. The transmission characteristics of the power-line carrier are very significant in signal propagation. This paper presents field test and simulation results concerning signal transmission on power lines in underground and aerial installations within the CENELEC EN 50065-1 B band. Field test results show the consistency to the transmission line theory and modal wave propagation. The well-known Alternate Transients Program-Electromagnetic Transients Program (ATP-EMTP) is used for the simulation of the transmission path. Simulation results, obtained for different operational cases and configurations, are compared to the actual measurements from field tests, showing satisfactory agreement. Finally, the proposed models are used in further investigations concerning the signal transmission. [ABSTRACT FROM AUTHOR]

Collybistin (Cb) is a brain-specific guanine nucleotide exchange factor that has been implicated in plasma membrane targeting of the postsynaptic scaffolding protein gephyrin found at glycinergic and GABAergic synapses. Here we show that Cb-deficient mice display a region-specific loss of postsynaptic gephyrin and GABAA receptor clusters in the hippocampus and the basolateral amygdala. Cb deficiency is accompanied by significant changes in hippocampal synaptic plasticity, due to reduced dendritic GABAergic inhibition. Long-term potentiation is enhanced, and long-term depression reduced, in Cb-deficient hippocampal slices. Consistent with the anatomical and electrophysiological findings, the animals show increased levels of anxiety and impaired spatial learning. Together, our data indicate that Cb is essential for gephyrin-dependent clustering of a specific set of GABAA receptors, but not required for glycine receptor postsynaptic localization. [ABSTRACT FROM AUTHOR]

Examines the organization of the active site of the thyrotropin-releasing hormone-degrading ectoenzyme (TRH-DE), a TRH-specific peptidase that catalyzes the inactivation of the peptidergic signal substance TRH. Enzymatic activity of wild-type and mutated TRH-DEs and the inhibitory potencies of various classes of inhibitors; Differences in the evolution of the active sites and in the mechanism of action between TRH-DE and APA.

Analyzes the structure of thyrotropin-releasing hormone-degrading ectoenzyme of cysteine residues. Characterization of thyrotropin-releasing hormone-degrading ectoenzyme; Analysis on protein-protein interactions; Occurrence of enzymatic activity and trafficking in the cell surface.