Injection by hydrostatic pressure in conjunction with electrokinetic force on a microfluidic chip

A simple method was developed for injecting a sample on a cross-form microfluidic chip by means of hydrostatic pressure combined with electrokinetic forces. The hydrostatic pressure was generated simply by adjusting the liquid level in different reservoirs without any additional driven equipment such as a pump. Two dispensing strategies using a floating injection and a gated injection, coupled with hydrostatic pressure loading, were tested. The fluorescence observation verified the feasibility of hydrostatic pressure loading in the separation of a mixture of fluorescein sodium salt and fluorescein isothiocyanate. This method was proved to be effective in leading cells to a separation channel for single cell analysis.

Does conurbation affect the risk of poor mental health? A population based record linkage study

To determine if urban residence is associated with an increased risk of anxiety/depression independent of psychosocial stressors, concentrated disadvantage or selective migration between urban and rural areas, this population wide record-linkage study utilised data on receipt of prescription medication linked to area level indicators of conurbation and disadvantage. An urban/rural gradient in anxiolytic and antidepressant use was evident that was independent of variation in population composition. This gradient was most pronounced amongst disadvantaged areas. Migration into increasingly urban areas increased the likelihood of medication. These results suggest increasing conurbation is deleterious to mental health, especially amongst residents of deprived areas

Systematic review of tools to measure outcomes for young children with autism spectrum disorder

BACKGROUND: The needs of children with autism spectrum disorder (ASD) are complex and this is reflected in the number and diversity of outcomes assessed and measurement tools used to collect evidence about children's progress. Relevant outcomes include improvement in core ASD impairments, such as communication, social awareness, sensory sensitivities and repetitiveness; skills such as social functioning and play; participation outcomes such as social inclusion; and parent and family impact.

OBJECTIVES: To examine the measurement properties of tools used to measure progress and outcomes in children with ASD up to the age of 6 years. To identify outcome areas regarded as important by people with ASD and parents.

METHODS: The MeASURe (Measurement in Autism Spectrum disorder Under Review) research collaboration included ASD experts and review methodologists. We undertook systematic review of tools used in ASD early intervention and observational studies from 1992 to 2013; systematic review, using the COSMIN checklist (Consensus-based Standards for the selection of health Measurement Instruments) of papers addressing the measurement properties of identified tools in children with ASD; and synthesis of evidence and gaps. The review design and process was informed throughout by consultation with stakeholders including parents, young people with ASD, clinicians and researchers.

RESULTS: The conceptual framework developed for the review was drawn from the International Classification of Functioning, Disability and Health, including the domains 'Impairments', 'Activity Level Indicators', 'Participation', and 'Family Measures'. In review 1, 10,154 papers were sifted - 3091 by full text - and data extracted from 184; in total, 131 tools were identified, excluding observational coding, study-specific measures and those not in English. In review 2, 2665 papers were sifted and data concerning measurement properties of 57 (43%) tools were extracted from 128 papers. Evidence for the measurement properties of the reviewed tools was combined with information about their accessibility and presentation. Twelve tools were identified as having the strongest supporting evidence, the majority measuring autism characteristics and problem behaviour. The patchy evidence and limited scope of outcomes measured mean these tools do not constitute a 'recommended battery' for use. In particular, there is little evidence that the identified tools would be good at detecting change in intervention studies. The obvious gaps in available outcome measurement include well-being and participation outcomes for children, and family quality-of-life outcomes, domains particularly valued by our informants (young people with ASD and parents).

CONCLUSIONS: This is the first systematic review of the quality and appropriateness of tools designed to monitor progress and outcomes of young children with ASD. Although it was not possible to recommend fully robust tools at this stage, the review consolidates what is known about the field and will act as a benchmark for future developments. With input from parents and other stakeholders, recommendations are made about priority targets for research.

FUTURE WORK: Priorities include development of a tool to measure child quality of life in ASD, and validation of a potential primary outcome tool for trials of early social communication intervention.

STUDY REGISTRATION: This study is registered as PROSPERO CRD42012002223.

FUNDING: The National Institute for Health Research Health Technology Assessment programme.

The Shading Sign: Is It Exclusive of Endometriomas?

OBJECTIVES: To investigate if the shading sign is an exclusive MRI feature of endometriomas or endometrioid tumors, and to analyze its different patterns. METHODS: Three hundred and fourty six women with adnexal masses who underwent 1.5/3-T MRI were included in this retrospective, board-approved study. The shading sign was found in 56 patients, but five cases were excluded due to lack of imaging follow-up or histological correlation. The final sample included 51 women. The type of tumor and the pattern of shading were recorded for each case. RESULTS: Thirty endometriomas and five endometrioid carcinomas were found. The remaining 16 cases corresponded to other benign and malignant tumors. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 93%, 59%, and 96%, respectively. Restricting the analysis to cystic lesions without solid or fat component, sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 96%, 94%, and 80%. Five shading patterns were identified: layering (15.7%), liquid-liquid level (11.8%), homogenous (45.1%), heterogeneous (11.8%), and focal/multifocal shading within a complex mass (19.6%). No significant correlation was found between these patterns and the type of tumor. CONCLUSIONS: The shading sign is not exclusive of endometriomas or endometrioid tumors. Homogenous shading was the most prevalent pattern in endometriomas and half of the cases with focal/multifocal shading within a complex mass were endometrioid carcinomas.

An economic appraisal of the wealth-health gradient

In this study we aim to investigate the health discrepancies arising from unequal economic status, known as the “wealth-health gradient”. Our sample comprises 47,163 individuals from 14 European countries in the SHARE Wave 4 (2011), representing the population aged 50 and older. Through a cross-sectional OLS regression model, we have tested the impact of country-level indicators to infer their effect on personal health and on the magnitude of the gradient. The results find that private expenditure yields, on average, a higher, but fast decreasing, health benefit than public expenditure; and that income inequality is irrelevant for reducing health inequalities.

A Relação entre a Resiliência e a Vulnerabilidade ao Stresse : estudo numa organização de práticas positivas

Este estudo analisou as inter-relações que se estabelecem entre resiliência e stresse numa organização de práticas positivas assumidas e outra sem assunção dessas práticas. Abordaram-se as temáticas stresse, resiliência, organizações positivas, coping, percorrendo a sua evolução histórica até à atualidade. Adotou-se uma metodologia de investigação de natureza quantitativa. A amostra final foi constituída por 141 inquéritos validados, com idades entre os 18 e os 65 anos. Avaliaram-se os níveis indicadores fatuais de resiliência, aplicando a Escala de Resiliência de Wagnild e Young (1993), traduzida e adaptada para o português por Pesce, et al. (2005), e avaliaram-se os níveis de stresse aplicando-se o Questionário de Vulnerabilidade ao Stresse (23 QVS) criado por Adriano Vaz-Serra (2000). Os instrumentos apresentaram as qualidades psicométricas exigidas (sensibilidade e fidedignidade), a ER apresentou o coeficiente alfa de Cronbach de 0,777 e a QVS23 de 0,759. Estudou-se a variabilidade do grau de resiliência e da vulnerabilidade ao stresse em função das variáveis (idade, sexo, escolaridade, estado civil, antiguidade na empresa e no posto de trabalho). Os resultados revelam diferenças significativas face à idade, e habilitações literárias na vulnerabilidade ao stresse. A variável estado civil exerce efeito diferencial na resiliência. Concluiu-se que o tipo de práticas não influi na resiliência. Os colaboradores das organizações positivas são menos vulneráveis ao stresse, nomeadamente nas dimensões “Condições de vida adversas” e “Dramatização de Existência”. Não se verificou correlação entre a resiliência e o stresse.

Automatic optical fibre feedback potometer for transpiration studies

A new automatic feedback potometer for physiological studies of water uptake by root systems is described. A dual-optical-fibre amplitude-modulating displacement transducer of improved sensitivity is employed to detect the changes in liquid level. The merits of optimal double-cut fibres, which make full use of the critical angle and improve coupling between the emitter and the receiver, have resulted in a sensor that is 64 times more responsive than the simple emitter - detector probe. Positioning the optical fibre transducer in a narrow capillary and using feedback to control the liquid level allows continuous measurement of volumes in the nanolitre range. The optical sensor used does not need re-calibration for the different salt solutions used in such studies.

Measuring European real estate investment performance: A comparison of different approaches

The performance of real estate investment markets is difficult to monitor because the constituent assets are heterogeneous, are traded infrequently and do not trade through a central exchange in which prices can be observed. To address this, appraisal based indices have been developed that use the records of owners for whom buildings are regularly re-valued. These indices provide a practical solution to the measurement problem, but have been criticised for understating volatility and not capturing market turning points in a timely manner. This paper evaluates alternative ‘Transaction Linked Indices’ that are estimated using an extension of the hedonic method for index construction and with Investment Property Databank data. The two types of indices are compared over Q4 2001 to Q4 2012 in order to examine whether movements in these indices are consistent. The Transaction Linked Indices show stronger growth and sharper declines than their appraisal based counterparts over the course of the cycle in different European markets and they are typically two to four times more volatile. However, they have some limitations; for instance, only country level indicators can be published in many cases owing to low trading volumes in the period studied.

Measuring European property investment performance: comparing different approaches

Purpose – Price indices for commercial real estate markets are difficult to construct because assets are heterogeneous, they are spatially dispersed and they are infrequently traded. Appraisal-based indices are one response to these problems, but may understate volatility or fail to capture turning points in a timely manner. This paper estimates “transaction linked indices” for major European markets to see whether these offer a different perspective on market performance. The paper aims to discuss these issues. Design/methodology/approach – The assessed value method is used to construct the indices. This has been recently applied to commercial real estate datasets in the USA and UK. The underlying data comprise appraisals and sale prices for assets monitored by Investment Property Databank (IPD). The indices are compared to appraisal-based series for the countries concerned for Q4 2001 to Q4 2012. Findings – Transaction linked indices show stronger growth and sharper declines over the course of the cycle, but they do not notably lead their appraisal-based counterparts. They are typically two to four times more volatile. Research limitations/implications – Only country-level indicators can be constructed in many cases owing to low trading volumes in the period studied, and this same issue prevented sample selection bias from being analysed in depth. Originality/value – Discussion of the utility of transaction-based price indicators is extended to European commercial real estate markets. The indicators offer alternative estimates of real estate market volatility that may be useful in asset allocation and risk modelling, including in a regulatory context.

Controlador preditivo não linear aplicado ao controle de golfadas em processos de produção de petróleo

Slugging is a well-known slugging phenomenon in multiphase flow, which may cause problems such as vibration in pipeline and high liquid level in the separator. It can be classified according to the place of its occurrence. The most severe, known as slugging in the riser, occurs in the vertical pipe which feeds the platform. Also known as severe slugging, it is capable of causing severe pressure fluctuations in the flow of the process, excessive vibration, flooding in separator tanks, limited production, nonscheduled stop of production, among other negative aspects that motivated the production of this work . A feasible solution to deal with this problem would be to design an effective method for the removal or reduction of the system, a controller. According to the literature, a conventional PID controller did not produce good results due to the high degree of nonlinearity of the process, fueling the development of advanced control techniques. Among these, the model predictive controller (MPC), where the control action results from the solution of an optimization problem, it is robust, can incorporate physical and /or security constraints. The objective of this work is to apply a non-conventional non-linear model predictive control technique to severe slugging, where the amount of liquid mass in the riser is controlled by the production valve and, indirectly, the oscillation of flow and pressure is suppressed, while looking for environmental and economic benefits. The proposed strategy is based on the use of the model linear approximations and repeatedly solving of a quadratic optimization problem, providing solutions that improve at each iteration. In the event where the convergence of this algorithm is satisfied, the predicted values of the process variables are the same as to those obtained by the original nonlinear model, ensuring that the constraints are satisfied for them along the prediction horizon. A mathematical model recently published in the literature, capable of representing characteristics of severe slugging in a real oil well, is used both for simulation and for the project of the proposed controller, whose performance is compared to a linear MPC

Método da histerese por auto-ajuste para minimização de esforço de controle no separador submarino VASPS

Neste trabalho apresenta-se o estudo do desenvolvimento de um controlador não-tradicional baseado em um mecanismo de histerese com auto-ajuste para o controle de nível de líquido de um sistema de separação e bombeio submarino conhecido como VASPS. O controlador desenvolvido gera sinais enviados para a bomba centrífuga submersa para controlar o nível de líquido no tanque do separador, evitando que ele atinja valores muito baixos que poderiam danificar a bomba ou valores muito altos que reduziriam a eficiência da separação líquido/gás. Os sinais de controle gerados pelo controlador visam solicitar a bomba o mínimo possível de modo a evitar o seu desgaste e falhas prematuras. Nas simulações, o controlador desenvolvido foi testado sob grandes variações nas condições de operação, tais como golfadas, produzindo resultados bastante satisfatórios e promissores.

Sintonia de controlador fuzzy por algoritmo genético em sistema de nível de líquidos

O presente trabalho demonstra a aplicação de um Algoritmo Genético com o intuito de projetar um controlador Fuzzy MISO, através da sintonia de seus parâmetros, em um processo experimental de nivelamento de líquido em um tanque, cuja dinâmica apresenta características não-lineares. Para o projeto e sintonia do controlador, foi utilizado o suporte do software Matlab, e seus pacotes Simulink e Global Optimization Toolbox. O Controlador Fuzzy ora projetado teve seu desempenho avaliado através de ensaios em tempo real em um Sistema de Nível de Liquido.

Closed-loop stable model predictive control of integrating systems with dead time

Model predictive control (MPC) applications in the process industry usually deal with process systems that show time delays (dead times) between the system inputs and outputs. Also, in many industrial applications of MPC, integrating outputs resulting from liquid level control or recycle streams need to be considered as controlled outputs. Conventional MPC packages can be applied to time-delay systems but stability of the closed loop system will depend on the tuning parameters of the controller and cannot be guaranteed even in the nominal case. In this work, a state space model based on the analytical step response model is extended to the case of integrating time systems with time delays. This model is applied to the development of two versions of a nominally stable MPC, which is designed to the practical scenario in which one has targets for some of the inputs and/or outputs that may be unreachable and zone control (or interval tracking) for the remaining outputs. The controller is tested through simulation of a multivariable industrial reactor system. (C) 2012 Elsevier Ltd. All rights reserved.

Modeling and simulation of severe slugging with mass transfer effects

A mathematical model and numerical simulations are presented to investigate the dynamics of gas, oil and water flow in a pipeline-riser system. The pipeline is modeled as a lumped parameter system and considers two switchable states: one in which the gas is able to penetrate into the riser and another in which there is a liquid accumulation front, preventing the gas from penetrating the riser. The riser model considers a distributed parameter system, in which movable nodes are used to evaluate local conditions along the subsystem. Mass transfer effects are modeled by using a black oil approximation. The model predicts the liquid penetration length in the pipeline and the liquid level in the riser, so it is possible to determine which type of severe slugging occurs in the system. The method of characteristics is used to simplify the differentiation of the resulting hyperbolic system of equations. The equations are discretized and integrated using an implicit method with a predictor-corrector scheme for the treatment of the nonlinearities. Simulations corresponding to severe slugging conditions are presented and compared to results obtained with OLGA computer code, showing a very good agreement. A description of the types of severe slugging for the three-phase flow of gas, oil and water in a pipeline-riser system with mass transfer effects are presented, as well as a stability map. (C) 2011 Elsevier Ltd. All rights reserved.

Disparities in treatment rates of paediatric end-stage renal disease across Europe: insights from the ESPN/ERA-EDTA registry.

BACKGROUND Considerable disparities exist in the provision of paediatric renal replacement therapy (RRT) across Europe. This study aims to determine whether these disparities arise from geographical differences in the occurrence of renal disease, or whether country-level access-to-care factors may be responsible. METHODS Incidence was defined as the number of new patients aged 0-14 years starting RRT per year, between 2007 and 2011, per million children (pmc), and was extracted from the ESPN/ERA-EDTA registry database for 35 European countries. Country-level indicators on macroeconomics, perinatal care and physical access to treatment were collected through an online survey and from the World Bank database. The estimated effect is presented per 1SD increase for each indicator. RESULTS The incidence of paediatric RRT in Europe was 5.4 cases pmc. Incidence decreased from Western to Eastern Europe (-1.91 pmc/1321 km, P < 0.0001), and increased from Southern to Northern Europe (0.93 pmc/838 km, P = 0.002). Regional differences in the occurrence of specific renal diseases were marginal. Higher RRT treatment rates were found in wealthier countries (2.47 pmc/€10 378 GDP per capita, P < 0.0001), among those that tend to spend more on healthcare (1.45 pmc/1.7% public health expenditure, P < 0.0001), and among countries where patients pay less out-of-pocket for healthcare (-1.29 pmc/11.7% out-of-pocket health expenditure, P < 0.0001). Country neonatal mortality was inversely related with incidence in the youngest patients (ages 0-4, -1.1 pmc/2.1 deaths per 1000 births, P = 0.10). Countries with a higher incidence had a lower average age at RRT start, which was fully explained by country GDP per capita. CONCLUSIONS Inequalities exist in the provision of paediatric RRT throughout Europe, most of which are explained by differences in country macroeconomics, which limit the provision of treatment particularly in the youngest patients. This poses a challenge for healthcare policy makers in their aim to ensure universal and equal access to high-quality healthcare services across Europe.