bluuebunny/crossref_metadata_2025 huggingface dataset:
Educational outcomes are predictive of mental health diagnoses in adolescence
Authors: Wong Janice , Fletcher Janet , Glauert Rebecca , O'Donnell Melissa , Bayliss Donna
Published: April 2017

ABSTRACTObjectivesAssociations between poor reading outcomes and attention/behavioural difficulties have been documented in the literature (e.g., Spira & Fischel, 2005), however the research regarding the relationship between reading achievement and internalising mental health disorders (e.g., mood disorders, anxiety) is scarce. As children experience a large proportion of their development in the school context, it is essential to understand the nature of this relationship, as it may inform a population based approach to reducing the risk of mental health disorders.

ApproachThis study was a retrospective cohort study, and utilised population level administrative data. Participants included all children born in Western Australia between 1992 and 1996. Individuals were followed until 2011 for their mental health outcomes. Using Cox regressions, variables reflecting child, family, and community factors, as well as factors from the school context were used to predict the risk of any mental health disorder, and also more specifically, an internalising or externalising mental health disorder.

ResultsAfter controlling for a number of demographic risk factors, poor reading achievement in Year 3 and Year 7 appeared to be associated with poor mental health when all mental health diagnostic codes were considered as a single entity. However, when mental health was grouped into internalising or externalising mental health disorders, findings showed that reading achievement in the top 20% of the cohort was associated with an increased risk of an internalising disorder, whilst reading achievement in the bottom 20% of the cohort was associated with an increased risk of an externalising disorder.

ConclusionThis study found that reading achievement is associated with mental health, but the nature of this relationship appears to be dependent on the type of mental health disorders that are considered. A more complex relationship between reading achievement and poor mental health was revealed when the mental health diagnoses were grouped into internalising and externalising disorders. Whilst further research is required to understand the factors that may mediate these relationships (e.g., perfectionism for high achieving students), the provision of support to both ends of the achievement spectrum may play a role in reducing the risk of adolescent mental health disorders.
The impact of the Population Health Research Network on linked data research capacity in Australia
Authors: Flack Felicity , Wray Natalie , Smith Merran
Published: April 2017

ABSTRACTObjectivesIn 2009 Australian governments and academic institutions made a substantial investment to establish the Population Health Research Network (PHRN), a distributed research infrastructure network which provides Australian researchers with state-of-the-art data linkage facilities and services. The infrastructure operates on a collaborative, national, non-exclusive basis and enables Australian researchers to address key national and global challenges.

We have conducted a review of the PHRN’s progress over the last 6 years in achieving its objectives of:1. increasing the data linkage research capacity in Australia2. enabling research in national priority areas.

ApproachProgress with achieving the first objective was measured by comparing the data linkage facilities and services available in Australia in 2008-09 with those available in 2014-15. The following categories of services and facilities were used in the analysis:

Linkage facilities

Application, access and storage facilities

Information, training and education

Changes in usage of the data linkage infrastructure over the period 2008-09 to 2014-15 were measured.

The second objective was achieved by using bibliometrics to assess academic impact, in the form of citations, of peer-reviewed publications which arose from use of the PHRN infrastructure. The topics of all of the publications were compared to health priority areas to determine the extent to which the infrastructure has been used to inform national priorities.

ResultsThere has been a significant expansion of the data linkage facilities from a small number of jurisdictional data linkage units to a distributed network of data linkage units servicing researchers in every state and territory. A cross-jurisdictional data linkage capability has also been established as well as a national online data application system, a secure remote access laboratory and a secure file transfer system. A variety of information, training and education has been provided to stakeholders. The expansion of the facilities and services has seen usage of data linkage units triple since 2011-12.

The number of peer-reviewed publications resulting from the use of the PHRN infrastructure has increased every year since 2011-12. There were 111 publications in 2014-15. Areas of high burden of disease in Australia, cancer, cardiovascular and endocrine diseases are highly represented in the publications.

ConclusionThere has been a significant increase in data linkage research infrastructure in Australia from 2008-09 to 2014-15. This has resulted in an increase in both the number of research projects conducted using linked data and the number of related peer-reviewed publications.
Describing the Linkages of the Citizenship and Immigration Canada Permanent Resident Data and Vital Statistics—Death Registry to Ontario’s Administrative Health Database
Authors: Guttmann Astrid , Chiu Maria , Lebenbaum Michael , Lam Kelvin , Chong Nelson , Azimaee Mahmoud , Iron Karey , Manuel Doug
Published: April 2017

ABSTRACTObjectives Ontario, the most populous province in Canada, has a universal healthcare system that routinely collects health administrative data on its 13 million legal residents that is used for health research. Record linkage has become a vital tool for this research by enriching this data with the Immigration, Refugees and Citizenship Canada (IRCC) Permanent Resident database and the Office of the Registrar General’s Vital Statistics-Death (VSD) registry. Our objectives were to estimate linkage rates and compare characteristics of individuals in the linked versus unlinked files.

Approach We used both deterministic and probabilistic linkage methods to link the IRCC database (1985-2012) and VSD registry (1990-2012) to the Ontario’s Registered Persons Database. Linkage rates were estimated and standardized differences were used to assess differences in socio-demographic and other characteristics between the linked and unlinked records.

Results The overall linkage rates for the IRCC database and VSD registry were 86.4% and 96.2%, respectively. The majority (68.2%) of the record linkages in IRCC were achieved after the three deterministic passes with the remaining 18.2% being linked probabilistically. Similarly the majority (79.8%) of the record linkages in the ORGD were linked using deterministic record linkage and the remaining 16.3% were linked after probabilistic and manual review. Unlinked and linked files were similar for most characteristics, such as age and marital status for IRCC and sex and most causes of death for VSD. However, lower linkage rates were observed among people born in East Asia (78%) in the IRCC database and certain causes of death in the VSD registry, namely perinatal conditions (61.3%) and congenital anomalies (81.3%).

Conclusion The linkages of immigration and vital statistics data to existing population-based healthcare data in Ontario, Canada will enable many novel cross-sectional and longitudinal studies to be conducted. Analytic techniques to account for sub-optimal linkage rates may be required in studies of certain ethnic groups or certain causes of death among children and infants.
Treatment choices for managing glucose control in impaired renal function: Interim Results
Authors: Davies Gareth , Stephens Jeff , Rice Sam , Chess James
Published: April 2017

ABSTRACT

ObjectivesPatients with chronic kidney disease (CKD ≥3) and diabetes mellitus comprise approximately 25% patients with diabetes. These patients are at a higher risk of cardiovascular morbidity and mortality and furthermore therapies targeting glucose control are limited. The management of glycaemic control in type 2 diabetes and chronic renal disease is difficult with limited therapeutic choices. This issue has been a matter of longstanding debate. Following a number of joint Diabetes-Renal meetings between the Diabetes and Renal teams based in Hywel Dda and ABM University Health Boards, a proposal was put forward to the SAIL team to examine the relationship between diabetes therapies in relation to eGFR, as this may influence further practice and guidance for patients with type 2 diabetes and renal impairment.

ApproachLinkage and re-use of routinely collected anonymised clinical data held in the SAIL databank was employed, to identify a cohort of adult patients in Abertawe Bro Morgannwg Health Board (ABMU) having type 2 diabetes (excluding type 1 diabetes). Diagnosis of diabetes was achieved by use of National Health Service ‘Read’ codes. Creatinine, eGFR, age, gender, weight, height, cholesterol, LDL, HDL, TG, systolic blood pressure, diastolic blood pressure, diabetes medication prescriptions, the use of statins, ACEis, aspirin, CHD status, CVD status, duration of diabetes were identified in primary care GP and pathology datasets.

Results42170 (6.0%) of adults in ABMU were identified as having type 2 (excluding type 1) diabetes , 13369 of which had good GP registration coverage. The gender split was male 56%, female 44%. Duration of diabetes (years) was (mean/median/SD/IQR) 9.96/8.97/6.78/8.10; weight (Kg) was 86.94/85.00/21.23/28.19; age (years) 65.49/66.74/13.75/19.03; BMI 31.57/30.70/6.62/7.99. Incidence of CKD as defined by GP coded data was 24%, renal replacement therapy 0.4%, Ischaemic Heart Disease 22%. Prevalence of prescriptions during 2014 was: Anti-diabetic medication 72%, statins 75%, aspirin 34%, ACEi/ARB 61%. The import of pathology laboratory data into SAIL is currently pending, and is anticipated before April 2016. This will allow the accurate stratification of CKD status and detailed description of use of anti-diabetic agents.

ConclusionThe project methods and coding structure are well place to provide anticipated results as soon as pathology data arrives. The percentage of ABMU patients having type 2 diabetes is in line with other literature for adults in the UK.
A Systems Dynamic Approach to Alzheimer’s Disease Prevention
Authors: Sabounchi Nasim S.
Published: April 2017

ABSTRACT

ObjectivesAs estimated there are about 5.3 million who suffer from Alzheimer’s disease in United States. The incidence is increasing as the population is aging. Due to the increasing trend of Alzheimer’s disease, there is a lot of discussion on prevention efforts or slowing the incidence. Also, models that could predict individual risk of cognitive impairment are needed to assist in prevention efforts. 

In general dementia development has been associated with growth in various vascular, lifestyle and other risk factors. Epidemiological research provides evidence of some vascular, lifestyle and psychological risk factors that are modifiable and protective of disease incidence either independently or while interacting with other factors. However, as reported by National Institute of Aging, it is not yet clear whether health or lifestyle factors can prevent Alzheimer’s disease.

The objective of this research project is to adopt a system dynamics modeling approach to study the interaction of several key factors including vascular, lifestyle and psychological aspects over the life course of individuals, to gain further understanding of Alzheimer’s disease incidence and evaluate prevention strategies. Both datasets of ‘Alzheimer's Disease Neuroimaging Initiative (ADNI)’ and ‘Health and Retirement Study (HRS)’ will be used for model development and validation.

ApproachA system dynamics approach is an optimal choice for addressing the goal of this proposal because different key factors interact over time and make Alzheimer’s disease incidence a complex problem. Furthermore, system dynamics approaches focus on understanding the relationship between the structure of a system and the resulting dynamic behaviors generated through multiple interacting feedback loops. Such an approach could be invaluable in studying dynamic problems arising in complex health, social, economic, or ecological systems.

ResultsFor the purpose of the proposal, the following stages are planned:1. Develop a system dynamics simulation model at individual level that predicts the Alzheimer’s disease incidence over the life course, and aggregates individual level models to predict population level trends

2. Calibrate the resulting simulation model based upon longitudinal data trends employed from Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Both cohorts with Alzheimer’s disease and control subjects from this database will be used to fine-tune the simulation model.

ConclusionThe final validated model would be used to test different hypotheses and evaluate various strategies and/or their combinations to help evaluate the efficacy of prevention strategies on Alzheimer’s disease incidence and its growth.
The other side of the coin: harm due to the non-use of health-related data
Authors: Jones Kerina , Laurie Graeme , Stevens Leslie , Dobbs Christine , Ford David , Lea Nathan
Published: April 2017

ABSTRACTObjectivesIt is widely acknowledged that breaches and misuses of health-related data can have serious implications and consequently they often carry penalties. However, harm due to the omission of health data usage, or data non use, is a subject that lacks attention. A better understanding of this other side of the coin is required before it can be addressed effectively. ApproachThis article uses an international case study approach to explore why data non use is difficult to ascertain, the sources and types of health-related data non-use, its implications for citizens and society and some of the reasons it occurs. It does this by focussing on issues with clinical care records, research data and governance frameworks and associated examples of non-use. ResultsThe non-use of health-related data is a complex issue with multiple sources and reasons contributing to it. Instances of data non-use can be associated with harm, but taken together they describe a trail of data non-use, and this may complicate and compound its impacts. Actual evidence of data non-use is sparse and harm due to data non use is difficult to prove. But although it can be nebulous, it is a real problem with largely unquantifiable consequences. There is ample indirect evidence that health data non-use is implicated in the deaths of many thousands of people and potentially £billions in financial burdens to societies.ConclusionThe most effective initiatives to address specific contexts of data non-use will be those that are cognisant of the multiple aspects to this complex issue, in order to move towards socially responsible reuse of data becoming the norm to save lives and resources.
Weighted multiple imputation of ethnicity data that are missing not at random in primary care databases
Authors: Pham Tra My , Petersen Irene , Carpenter James , Morris Tim
Published: April 2017

ABSTRACT

BackgroundEthnicity is an important factor to be considered in health research because of its association with inequality in disease prevalence and the utilisation of healthcare. Ethnicity recording has been incorporated in primary care electronic health records, and hence is available in large UK primary care databases such as The Health Improvement Network (THIN). However, since primary care data are routinely collected for clinical purposes, a large amount of data that are relevant for research including ethnicity is often missing. A popular approach for missing data is multiple imputation (MI). However, the conventional MI method assuming data are missing at random does not give plausible estimates of the ethnicity distribution in THIN compared to the general UK population. This might be due to the fact that ethnicity data in primary care are likely to be missing not at random. ObjectivesI propose a new MI method, termed ‘weighted multiple imputation’, to deal with data that are missing not at random in categorical variables.MethodsWeighted MI combines MI and probability weights which are calculated using external data sources. Census summary statistics for ethnicity can be used to form weights in weighted MI such that the correct marginal ethnic breakdown is recovered in THIN. I conducted a simulation study to examine weighted MI when ethnicity data are missing not at random. In this simulation study which resembled a THIN dataset, ethnicity was an independent variable in a survival model alongside other covariates. Weighted MI was compared to the conventional MI and other traditional missing data methods including complete case analysis and single imputation.ResultsWhile a small bias was still present in ethnicity coefficient estimates under weighted MI, it was less severe compared to MI assuming missing at random. Complete case analysis and single imputation were inadequate to handle data that are missing not at random in ethnicity.ConclusionsAlthough not a total cure, weighted MI represents a pragmatic approach that has potential applications not only in ethnicity but also in other incomplete categorical health indicators in electronic health records.
Generation Scotland: using data linkage for longitudinal studies
Authors: Campbell Archie
Published: April 2017

ABSTRACTObjectivesGeneration Scotland: Scottish Family Health Study (GS:SFHS) is a family-based genetic epidemiology study of ~24,000 volunteers from ~7000 families recruited across Scotland between 2006 and 2011 with the capacity for follow-up through record linkage and re-contact.

ApproachParticipants completed a demographic, health and lifestyle questionnaire and provided biological samples including DNA, and 90% underwent detailed clinical assessment, including anthropometric, cardiovascular, respiratory, cognition and mental health. The biological samples, phenotype and genotype data collected form a resource with broad consent for academic and commercial research on the genetics of health, disease and quantitative traits of current and projected public health importance. Features include the family-based recruitment; breadth and depth of phenotype information, with detailed data on cognition, personality and mental health. GWAS and exome genotype data is available on most of the cohort. These features maximise the power of the resource to identify, replicate or control for genetic factors associated with a wide spectrum of illnesses and risk factors. By linkage to routine NHS hospital, lab tests, prescribing and dental records this has become a longitudinal dataset, using the Scottish Community Health Index (CHI).

Results Researchers are now able to use the dataset to find prevalent and incidental disease cases, and healthy controls, to test research hypotheses on a stratified population. They can also do targeted recruitment of participants to new studies, utilising the NHS CHI register for up to date contact details. There are 6 published papers on a variety of conditions and currently around 10 ongoing studies based on our record linkage capabilities.

ConclusionWe have thoroughly tested the linkage process and plan to extend it to include primary care data (GP records) in the next year. There are current or planned collaborations looking into heart disease, diabetes, breast and colon cancers, depression, neuropathic pain, Alzheimer’s disease and dementia. Generation Scotland is also a contributor to major international consortia. The resources are available to academic and commercial researchers through a managed access process.
El premio nobel alrededor del ADN
Authors: Delgadillo-Álvarez Dulce María
Published: April 2017

El Premio Nobel es un galardón internacional otorgado cada año a personas o instituciones que hayan realizado investigaciones, descubrimientos o contribuciones a la humanidad en el año inmediato anterior o en el transcurso de su vida. Los premios se instituyeron en 1895 como última voluntad del químico sueco Alfred Nobel y comenzaron a entregarse en 1901. Dos de las especialidades en las que el Premio es otorgado son en Química y en Fisiología o Medicina. El objetivo de esta breve revisión es hacer un recuento de aquellos investigadores que han sido merecedores de este galardón en las disciplinas citadas desde hace 114 años y cuyos trabajos han orbitado alrededor del ácido desoxirribonucleico o ADN. Se mencionan estudios sobre su descubrimiento, estructura y caracterización molecular tanto de esta como de las moléculas que, en coordinación con él lo hacen ser la molécula encargada de almacenar y transmitir la información genética de todos los organismos que habitan nuestro planeta.Palabras clave: Premio Nobel, ácido desoxirribonucleico, descubrimiento, estructura, biología molecular
Clasificación de dos tareas mentales haciendo uso mapas autoorganizativos de kohonen (SOM)
Authors: Diaz Sotelo Wilber , Joya Gonzalo , García-Lagos Francisco
Published: April 2017

En este trabajo se llevó a cabo la clasificación de patrones correspondientes a dos tareas mentales, obtenidos mediante un sistema BCI (Brain Computer Interface). Para ello se utilizó el paradigma neuronal de los Mapas Autorganizativos de Kohonen (SOM, por Self-Organizing Maps). Los patrones utilizados en cada clasificador se obtuvieron mediante la aplicación de la Transformada Rápida de Fourier a las señales EEG directamente proporcionadas por el sistema BCI. En una primera fase, las capturas de los patrones se realizaron a lo largo de ocho segundos, pero una red SOM es implementada y entrenada de manera independiente para cada segundo.  La SOM con el mejor rendimiento se usó en la segunda fase (fase de trabajo), para clasificar todos los segundos. Los resultados obtenidos en las pruebas de validación proporcionan un porcentaje de error entre 3.75%, (para los segundos 5° y 6°), y 11.25% para el 8°. Estos errores son menores o similares a los resultados obtenidos en otros trabajos de referencia.Palabras claves: Interfaz Cerebro Computadora BCI, Mapas Autorganizativos de Kohonen, Fast Fourier Transform FFT, electroencefalograma EEG, Clasificación de tareas mentales.
Dependencia emocional de pareja en mujeres atendidas en una clínica universitaria de Lima, 2014
Authors: Sartori Flores Karen , De La Cruz Valdiviano Carlos
Published: April 2017

Se investigó la dependencia emocional de pareja en mujeres atendidas en una clínica universitaria de Lima, para lo cual se seleccionó una muestra de 60 participantes, a quienes se aplicó el Inventario IDE (Aiquipa, 2012) y se obtuvo un 80% de personas con dependencia emocional de pareja. En el análisis comparativo se encontraron medias más altas de dependencia emocional de pareja en mujeres de estado civil solteras a diferencia (p=0,05) de estado civil casadas, convivientes y divorciadas. Asimismo, esta diferencia significativa (p<0,05) se evidencia en usuarias con un grado de instrucción técnico-superior contrastadas con instrucción primaria, secundaria y superior universitaria.
A Relevant Inrush Current Limitation Based on SCRs’ Smart Control Used in EV Battery Chargers
Authors: S. Jacques  , C. Reymond  , G. Benabdelaziz  , J.-C. Le Bunetel
Published: April 2017

In this article, an active inrush current limiter based on the phase shift control of silicon controlled rectifiers (SCRs) is proposed. These SCRs are used in medium power AC-DC converters (up to 3.7 kW) for electric vehicle (EV) charging systems. The control strategy consists in adjusting the triggering delay of SCRs both to limit the peak value of inrush current spikes and accelerate the charge of the DC-link capacitor of the converter. A modeling of the AC-DC converter, based on mathematical calculations, is necessary to implement the control strategy of the SCRs. Experimental test results demonstrate the robustness of the method, and confirm the modeling results.
Study on Application Usage Scheduling considering Usage Pattern in HEMS
Authors: Je-Seok Shin  , Dae-Sik Lim  , Jin-O Kim
Published: April 2017

In HEMS, a residential power consumer can use power efficiently and participate the demand response according to an electricity price or other conditions. An optimal usage scheduling for appliances is the main function of HEMS, which generally attempts to minimize the expense on power consumption. However, user’s convenience should be considered in determining when an appliance is used, or how much power is consumed. User’s convenience is related with the usage pattern, and this paper introduce a methodology for modelling the usage pattern using copula function. From cumulative data for the appliance usage, a dependence between the appliance usage and factors affecting the usage is represented by copula function. By copula function with the dependence, a usage pattern for the next day is obtained. And, the modelled pattern is reflected to a scheduling problem as the constraint. In order to explain the methodology and its application, as an example, modelling the pattern and scheduling for an electric heater are carried out.
Supraharmonics Emission Assessment of Multi-level Converters Applied for Photovoltaic Grid-Connected Inverters
Authors: T. Busatto  , A. Larsson  , S. K. Rönnberg  , M. H. J. Bollen
Published: April 2017

Topologies for different DC-AC converters used on grid-connected photovoltaic (PV) inverters are analysed and compared within this paper. The main focus is to evaluate the supraharmonic emission in the frequency range 2 to 150 kHz. For this study three topologies are evaluated: Neutral Point Clamped (NPC), the Cascaded H-bridge (CHB) and the Flying Capacitor (FC). To approximate the operation closer to a real scenario, the converters are analysed under the presence of voltage waveform distortion in the power supply. The simulation is performed using PSpice for the converters and Simulink for the grid. The characterization is made by the quantification of harmonics and supraharmonics, and also by the frequency domain analysis of the output current. Finally, a comparison of the chosen technologies is carried out, given a better understanding on the elements which exert influence on this type of emission.
Proposal of a Supervisory System for Energy Microgeneration Case Study Granja Colombari
Authors: Otto R. B.  , Alvarez-Ferreira L. R.  , Silva F.P.  , Santos R. F.  , Nogueira C. E. C.  , De Souza S. N. M.  , Frigo J. P.  , Ando Junior, O. H.
Published: April 2017

The generating units form a distributed power generator system that uses biogas as fuel, which is produced on small farms that collect the waste from agricultural activities systems. The supervisory system of a biogas generation unit can monitor local and remote environmental, electrical and mechanical variables of the process and display this data in a user-friendly interface for analysis and decision-making. In addition to the user interface, the collected data will be stored to build the process history and analysis database that will be used as a study source and promotion of new research lines related to this topic.
Optimization of Residential Load Consumption during Energy Peaks using Smart Metering
Authors: Rovan Refaat El-Razky  , Ahmed Ali Daoud  , Kamel El-serafi
Published: April 2017

Recently smart demand side management (DSM) is a very important tool that permits customers to take right decisions for their energy consumption and helps the energy utilities to decrease the over load demand and reshape the load curve. This paper proposes an optimized DSM technique based on smart metering uses different techniques such as load shifting and peak clipping to minimize domestic power consumption especially during load peaks. A new optimization technique (Bat Algorithm) is applied on proposed system and then compares results with other optimization techniques (Genetic Algorithm and Interior point Algorithm) to optimize the minimum consumption during peak hours according to load type. A control algorithm is applied to the proposed system to achieve the load shifting and load clipping according to the optimization results.
A Study on Optimal and Stable Strategy of Islanded Microgrid
Authors: Min-Hyeok Kang  , Ngoc-Thinh Quach  , Sang Heon Chae  , Dong Wan Kim  , Seung Hun Ko  , Eel-Hwan Kim  , Seong-Bo Oh
Published: April 2017

This paper presents a study on optimal and stable operation strategy of an islanded microgrid. By considering the minimum power limit of the DG, the operating strategy is discussed in order to analyze the stability of the microgrid. Then, a method based on particle swarm optimization (PSO) algorithm is used to achieve multi-objective optimization such as the maximized renewable energy source penetration, the minimized CO2 emission, and the reliability of microgrid. The proposed operation strategy will be verified by using Matlab programming, PSCAD simulation program and measured data from power system on Chuja Island in 2015.
Analysis and computer modelling of a Rate of Change of Frequency Relay for islanding detection in the software ATPDraw
Authors: T. S. Menezes  , Y. V. Tresso  , G. J. Schäffer  , F. A. M. Moura  , M. V. B. Mendonça  , P. H. O. Rezende  , M. R.  M. Castillo
Published: April 2017

Although the distributed generation is bringing many benefits to the grid, its operation is also getting even more complicated due to the many loads and generators involved into it. One important issue that must be detected as fast as possible to avoid any damage for the grid and/or the loads connected is the islanding. The paper analyses the modelling of a relay based in a passive method of islanding detection for the software ATPDraw, which is current unavailable. So we focussed in a model based in the frequency, which the rate of change of frequency relay - ROCOF - was chosen. The results show that the relay was successful to detect the islanding under various circumstances and is obeying the requisites established by the IEEE 1547.
Comparative analysis methodologies formulation powers in the frequency domain
Authors: G.J. Schäffer  , S.L.Modesto  , T. S. Menezes  , Y. V. Tresso  , F. A. M. Moura  , M. V. B. Mendonça  , P. H. O.  Rezende  , M. R. M. Castillo
Published: April 2017

With the increasing use of non-linear loads in electrical power systems, it is necessary to study the harmonic distortion, which if not considered in the power calculations may result in measurement errors. Therefore, this study aims to present a comparative analysis between two power theories in the frequency domain, Budeanu theory and IEEE 1459 standard, before a case study, in the presence or absence of distortions of a system electrical test.
Improving the Summation Law for Harmonic Current Emissions of Parallel Operated PV Inverters by Considering Equivalent Grid Impedance
Authors: Hasanali Moghadam  , Florian Ackermann  , Sönke Rogalla
Published: April 2017

For connection of a PV park to the electricity network, a pre-compliance study has to prove that the harmonic emissions at the point of common coupling (PCC) stays below the limits specified by the standards or local or national grid codes. An equation defined in IEC 61400-21 [1] is used to estimate the total harmonic current emission of the park at the PCC prior to installation. The equation uses the harmonic emission of a single inverter to predict the spectrum of the total current for a given number of identical inverters connected in parallel at the PCC. This paper considers the interaction of parallel operated inverters and the grid impedance. It proposes an approach based on the so called “equivalent grid impedance”, to improve the performance of summation law for evaluation of the current harmonics emissions at the PCC of PV parks. Improvement of this method would be helpful for power plant constructors.
Voltage Control Areas in Transmission Systems with Distributed Generation
Authors: W. R. Faria  , M. E. De Oliveira  , E. S. Hoji  , G. P. Viajante
Published: April 2017

Transmission systems’ main function is to transport active power from the generation source to the consumers. The presence of reactive power in a transmission system, on the other hand, is not desirable. Since the reactive power problem is characteristically local, its adjustment may be determined using devices placed near the consuming centers. Therefore, the system can be separated into regions and the reactive power problem be treated locally. This paper presents a computational tool for determining the voltage control areas (VCAs) in transmission systems based on the concept of electrical distance and the decoupled power flow method, which allows the treatment of the active and reactive power problems separately, reducing computational efforts. The presented tool also considers distributed generation and its influence on the voltage control areas. The tests have been conducted with IEEE 14 and 30 bus systems and proper conclusions are derived.
A literature survey on power quality disturbances in the frequency range of 2-150 kHz
Authors: S. Subhani  , V. Cuk  , J.F.G. Cobben
Published: April 2017

Modern power electronics emit high frequency disturbances which are the remnants of their internal switching circuits. The electromagnetic interference, induced by these high frequency disturbances, can cause household equipment and utility assets to malfunction. Due to the lack of standardization in the frequency range of 2-150 kHz, power electronic devices have been designed to satisfy emission limits at lower frequencies but instead have increased emission at this higher frequency range. This paper presents an up-to-date literature survey on these high frequency disturbances in the 2-150 kHz range, a.k.a. ‘supraharmonics’. It includes classification, standardization, equipment interaction, propagation, and mitigation methods. This survey shows that most research conducted on this topic has been empirical or using simple models. However, analytical/physical models with sufficient detail have to be developed for equipment and low-voltage networks in this frequency range to increase understanding of the practical impact on end-user equipment and assets in the distribution grid. Supraharmonics are a relatively new power quality problem and this emission is expected to increase progressively due to the growing number of high frequency emitting devices, and the increasing number of susceptible loads. Hence, more research towards higher frequency harmonics is warranted.
High-voltage Gain DC–DC Boost Converter with Coupled Inductors and Interleaved for a PV System to Supply Data Centers
Authors: K. L. Santos  , F. L. M. Antunes
Published: April 2017

This study presents the analysis and design of a high-voltage gain dc–dc converter applied to photovoltaic systems. A Battery bank rated at 24 V is connected to the input side, and the converter is responsible for stepping the voltage up to 311 V, in order to supply a Data Center to be used at IFRN’s Campus Verde (Federal Institute of Rio Grande do Norte’s Green Campus), where there is already a photovoltaic plant connected to the AC bus. The idea of a direct current supply is to improve the quality of energy delivered to such loads. This study proposes a converter topology with interleaved operation between two boost converters with coupled inductor and duplicity of the exit module to improve the ripple of the output voltage and reduce the high voltage on the output diode of converter, respectively. The Interleaved topology between two converters with a lag of the 180o promotes the reduction of output voltage ripple as well as filter elements, since it allows the load to receive the double of switching frequency, and doubles the total output power of the circuit. The interleaving concept reduces input current ripple and the input inductance size. In addition, the dimensioning voltage is not output voltage but capacitor voltage, which is lower than output voltage, reducing costs.
A Fixed-Frequency Soft-Switched Interleaved 3-Phase AC-to-DC Converter
Authors: Y. Du  , A.K.S. Bhat
Published: April 2017

This paper proposes a three-phase interleaved high frequency transformer isolated ac-dc converter that is suitable for small scale wind energy conversion systems employing permanent magnet synchronous generators. This configuration is realized by interleaving three identical single-phase single stage ac-dc converters obtained by integrating a rectifier, boost converter and fixed-frequency dual-tank LCL resonant converters. Based on a design example used for illustration purpose, a converter is designed and PSIM simulation results are presented for various operating conditions, such as balanced and unbalanced 3-phase operation; two-phase operation. It is shown that the converter maintains soft switching fore wide variation in supply voltage with low THD with high power factor.
Multistage configurations for hybrid thermosolar gas turbine power plants
Authors: C. Miguel  , R.P. Merchán  , M.J. Santos  , A. Calvo Hernández  , A. Medina
Published: April 2017

This work presents a thermodynamic model for a hybrid multistage Brayton thermosolar plant, with the aim of evaluating the efficiency and the power generation in different plant configurations. Improvements with respect a hybrid single stage Brayton thermosolar plant are proposed. This type of plants have two main energy sources for its operation, one from solar radiation, and the other one from the fuel combustion in a combustion chamber, making the values of the fuel consumption and the greenhouse emissions lower than other types of electric power generation plants. Moreover, this technology allows a stable power output (independent of solar irradiation fluctuations) without thermal storage systems.
Design, Simulation and Performance of a Four Phases Linear Variable Reluctance Motor
Authors: B. B. Miranda  , J. R. Camacho  , A. C. F. Mamede
Published: April 2017

The linear variable reluctance motor (LVRM) is a motor used in linear applications converting electromagnetic energy into linear movement and thrust. This paper aims at the analytical design of the machine and its validation through the finite element method. The design of a unilateral LVRM model of longitudinal flux type with passive translation movement is developed through the output power equation of the variable reluctance machine (VRM). The finite element analysis (FEA) is applied in order to check the values of inductance, the normal forces and propulsion. The FEA is also necessary to observe the undulation factor (ripple force), highly present in LVRM's, which produces vibration and acoustic noise. The analysis of the relationship between polar arcs and polar pitches plays an important role in the development of LVRM’s output force in the reduction of motor weight and volume. The LVRM model is developed from desired parameters, the maximum length of the stator, maximum speed and mass of the translator; through the design of a variable reluctance rotary motor (VRRM). The VRRM specifications are then converted into its linear equivalent. Keywords – finite elements; FEMM; ripple factor, ripple force; linear machines; variable reluctance motors.
Reduction of CO2 emissions using RES to recharge EVs: the Spanish case
Authors: A. Triviño  , M. Longo  , F. Foiadelli
Published: April 2017

This paper focuses on the field of transportation, which is greatly responsible for air pollution, mainly in cities and urban areas such as towns, airports and seaports. This work analyses the feasibility of integrating EVs and RES, focusing on the air pollution reduction benefits. To do so, we use the data collected in Spain. After an analysis of the energy production by RES and the size of the vehicle fleet over time in Spain, an evaluation of the number of completely green EVs as a function of the State Of Charge (SOC) and green energy used to charge the EV is proposed. Finally, the expected emissions reduction is derived when the vehicle fleet is changed by fully EVs fuelled with the wind and photovoltaic sources currently installed in Spain.
CFD Simulation of a Horizontal Axis Hydrokinetic Turbine
Authors: L.T. Contreras  , Y.U. López  , S. Laín
Published: April 2017

This study presents three-dimensional full transient numerical simulations of a horizontal axis hydrokinetic turbine, HAHT with particular emphasis on the analysis of its hydrodynamic characteristics. Hydrokinetic turbine performance is studied using a time-accurate Reynolds-averaged Navier Stokes (RANS) commercial solver. A physical transient rotor stator model with a sliding mesh technique is used to capture changes in flow field at a particular time step. A shear stress transport (SST) turbulence model has been employed to model the turbulent features of the flow. The studied rotor has three blades, based on NACA4412 airfoil. Two operation conditions have been considered: shaft parallel to the incoming flow (SP configuration) and shaft inclined an angle  around 30o regarding the main stream (SI configuration). As a result, the decrement of the hydrodynamic performance of the turbine with the inclined axis is quantitatively evaluated regarding that of the parallel axis. Moreover, a preliminary study of the vorticity dynamics in the wake of the inclined rotor is performed
«Manifestaciones intermediales de la literatura hispánica en el siglo XXI» de Gabriela Cordone y Victoria Béguelin-Argimón (eds.)
Authors: Campos López Ronald
Published: April 2017

Reseña del libro Manifestaciones intermediales de la literatura hispánica en el siglo XXI, de Gabriela Cordone y Victoria Béguelin-Argimón (eds.)
O ZONEAMENTO AMBIENTAL DA SILVICULTURA DO RIO GRANDE DO SUL. PRINCIPAIS ATORES E UMA PERSPECTIVA JURÍDICO-INSTITUCIONAL
Authors: Corrêa Augusto Ormazabal de Faria
Published: April 2017

O presente artigo analisa as relações jurídico-institucionais existentes entre os órgãos ambientais, órgão público do Estado e algumas empresas do setor da silvicultura do Rio Grande do Sul sob a ótica da Nova Economia Institucional (NEI). Como referencial teórico buscou-se literatura a respeito do Zoneamento Ambiental, da NEI e do setor da silvicultura no estado do Rio Grande do Sul. Para exequibilidade desse artigo foi realizada pesquisa exploratória, bibliográfica e coleta de dados junto a centros de pesquisa e universidade. Na análise e discussão de resultados, através da união entre a fundamentação teórica e a coleta de dados, foram demonstradas as dúvidas quanto à aplicação da legislação sobre o Zoneamento Ambiental e quanto à subordinação legal das instituições ambientais e sua atuação, bem como as divergências técnicas quanto às diretrizes utilizadas para a implementação desse instrumento.Palavras-chave:Zoneamento Ambiental; Silvicultura; Nova Economia Institucional; Legislação.AbstractThe present article analyzes the existent juridical-institutional relationships among environmental organizations, the State public sector and some companies of the forestry sector of Rio Grande do Sul under the optics of the New Institutional Economy (NIE). The literature about Environmental Zoning, NIE and the forestry sector in the state of Rio Grande do Sul were used as theoretical reference. An exploratory and bibliographical research and a collection of data by research centers and the university were done in order to accomplish this article. In the analysis and discussion of results, through the combination of theoretical foundation and the collection of data, doubts were demonstrated as to the application of the legislation on the Environmental Zoning regarding the legal subordination of the environmental institutions and their performance, as well as the technical divergences and the guidelines used for the implementation of this instrument.Keywords: Environmental Zoning; Forestry; New Institutional Economy; Legislation.
Estudio de casos y propuestas jurídicas para el ejercicio de la potestad sancionadora en los centros educativos
Authors: Conejo Rodríguez Alfonso
Published: April 2017

Existen múltiples investigaciones relacionadas con la violencia escolar, la mayoría tratando aspectos psicosociales y educativos. Sin embargo, faltan trabajos que aborden los aspectos administrativos y legales. Este artículo forma parte de una investigación más extensa, que comienza con una revisión del marco legislativo, y en la cual se comprobaron los aspectos que merecen mayor atención y las posibles causas del incumplimiento de las normas. El análisis documental de partes disciplinarios y expedientes sancionadores ponen de manifiesto la existencia de múltiples errores en la tramitación. Cuando los centros educativos tienen que adoptar medidas sancionadoras, es importante que el procedimiento no quede invalidado o pueda ser denunciado en los tribunales de justicia. Un cuestionario aplicado a los profesores, reveló que se sienten poco preparados para desempeñar esta función. A partir de los resultados obtenidos, se sugiere abordar la necesaria adaptación de la documentación elaborada en función de su autonomía, con la participación de todos los sectores de la comunidad educativa, y concretar aquellos aspectos que hagan del centro un lugar de convivencia, optimizando recursos en el marco de la legislación. Finalmente, se ofrecen conclusiones relacionadas con la necesidad de facilitar a los centros protocolos de actuación, y abordar procesos específicos de formación del profesorado.
La gestión integrada de recursos hídricos en la política federal del agua: propuesta para la nueva Ley General de Aguas en México
Authors: Cañez Cota Antonio
Published: April 2017

El propósito del presente artículo es proponer un esbozo de política pública federal en el contexto del debate de la recién aprobada Ley General de Aguas en México. Se parte de un diagnóstico estadístico y se analiza el proceso de política pública desde el establecimiento de la agenda hasta la evaluación, pasando por la definición del problema, el diseño y la implementación. La lección del artículo es que los principales desafíos de la gestión integrada de recursos hídricos en México se encuentran a nivel local y es necesario que la política federal enfatice en el fortalecimiento de los organismos a nivel de cuenca y de municipio, se propone la gobernanza corporativa pública como una alternativa para el fortalecimiento institucional local
Desautorización
Authors: GAPP Revista
Published: April 2017

La revista Gestión y Análisis de Políticas Públicas (GAPP), en aplicación de las recomendaciones de los comités internacionales de ética sobre publicaciones académicas, ha decidido proceder a la desautorización formal del siguiente artículo: Herrera Gómez, Manuel (2001) “Conocimiento sociológico y planificación social: la relación teoría y praxis”. GAPP (20): 71-91, el cual se ha traducido literalmente, figuras y notas incluidas, del capítulo 5 publicado con anterioridad de Donati, Pierpaolo (1991) Teoría relazionalle della società. Milán: Franco Angeli, según se ha comprobado.
Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes
Authors: Moreno-Marrodan Carmen , Liguori Francesca , Barbaro Pierluigi
Published: April 2017

The catalytic partial hydrogenation of substituted alkynes to alkenes is a process of high importance in the manufacture of several market chemicals. The present paper shortly reviews the heterogeneous catalytic systems engineered for this reaction under continuous flow and in the liquid phase. The main contributions appeared in the literature from 1997 up to August 2016 are discussed in terms of reactor design. A comparison with batch and industrial processes is provided whenever possible.