Mental playmates: Siblings, executive functioning and theory of mind

This study assessed the theory of mind (ToM) and executive functioning (EF) abilities of 124 typically developing preschool children aged 3 to 5 years in relation to whether or not they had a child-aged sibling (i.e. a child aged 1 to 12 years) at home with whom to play and converse. On a ToM battery that included tests of false belief, appearance-reality (AR) and pretend representation, children who had at least 1 child-aged sibling scored significantly higher than both only children and those whose only siblings were infants or adults. The numbers of child-aged siblings in preschoolers' families positively predicted their scores on both a ToM battery (4 tasks) and an EF battery (2 tasks), and these associations remained significant with language ability partialled out. Results of a hierarchical multiple regression analysis revealed that independent contributions to individual differences in ToM were made by language ability, EF skill and having a child-aged sibling. However, even though some conditions for mediation were met, there was no statistically reliable evidence that EF skills mediated the advantage of presence of child-aged siblings for ToM performance. While consistent with the theory that distinctively childish interaction among siblings accelerates the growth of both TOM and EF capacities, alternative evidence and alternative theoretical interpretations for the findings were also considered.

AS DIMENSÕES DA ORGANIZAÇÃO POSITIVA E SEUS IMPACTOS SOBRE O BEMESTAR DOS TRABALHADORES

Atualmente, características organizacionais vêm sendo estudadas sob um prisma diferenciado. Hoje, são pesquisados com maior ênfase os aspectos positivos que possam prover a possibilidade dos trabalhadores nutrirem sentimentos positivos para com suas organizações empregadoras e ao seu trabalho propriamente dito. Os desafios impostos atualmente giram em torno de se buscar identificar características organizacionais positivas que permitam o florescimento do trabalhador. Tais características são postuladas como benéficas tanto às organizações, por resultar em maior produtividade e lucratividade, assim como para promover o bem-estar dos trabalhadores. O objetivo deste estudo foi analisar os impactos que as dimensões da organização positiva exercem sobre o bem-estar dos trabalhadores. O bem-estar dos trabalhadores foi dividido em duas áreas, bem-estar subjetivo (composto por satisfação geral com a vida, afetos positivos e afetos negativos) e bem-estar no trabalho, composto por três dimensões: satisfação no trabalho, envolvimento com o trabalho e comprometimento organizacional afetivo. Organização positiva foi concebida como um construto composto por três dimensões: percepção de suporte organizacional, percepções de justiça organizacional (distributiva e de procedimentos) e confiança do empregado na organização. A amostra foi composta por 200 trabalhadores de diversas empresas do Estado de São Paulo, sendo 55 do sexo masculino e 145 do sexo feminino, solteiros e casados com escolaridade distribuída desde o ensino fundamental completo até pósgraduação completa. O instrumento de coleta de dados foi um questionário auto-aplicável composto por nove escalas que mediram as variáveis do estudo. Os resultados deste trabalho revelaram que bem-estar subjetivo e bem-estar no trabalho guardam relações entre si. Análises de regressão múltipla informaram que as dimensões da organização positiva tiveram impactos maiores sobre bem-estar no trabalho do que bem-estar subjetivo, destacando-se a capacidade de confiança do empregado na organização de prover explicações para o bem-estar de trabalhadores, seja nos domínios da vida pessoal ou no contexto de trabalho. Conforme tais resultados, confiança do empregado na organização, percepções de justiça e de suporte organizacional poderiam ser apontadas como importantes dimensões da organização positiva para promover e proteger o bem-estar dos trabalhadores. Futuros estudos deveriam incluir outras características organizacionais positivas para aumentar a explicação da variância do bem-estar dos trabalhadores

EXPERIÊNCIAS AFETIVAS NO CONTEXTO ORGANIZACIONAL E SEU IMPACTO SOBRE O BEM-ESTAR NO TRABALHO

Em ambiente de elevada pressão, competição e necessidade de criação de diferenciais consistentes que venham contribuir com a longevidade das organizações, nota-se a busca e, às vezes, radicais transformações nos modelos de gestão de negócios e gestão do ser humano no meio empresarial. No campo central dos estudos atuais acerca do comportamento humano e de suas relações com as diversas instituições em que o homem se vê inserido, figuram os esforços voltados à compreensão do papel e valor da contribuição do ser humano ao ambiente de trabalho e fortalecimento das organizações. Crescentes se mostram a preocupação e o entendimento sobre os fatores que impactam o bem-estar geral, o bem-estar no trabalho, a saúde dos trabalhadores e as variáveis emocionais oriundas das relações interpessoais comuns a todo organismo social. A combinação de temas emergentes e ricos em significância como bem-estar no trabalho, satisfação e envolvimento com o trabalho, comprometimento organizacional afetivo, emoções, afetos e sentimentos, caracterizam-se como um vasto e instigante campo de pesquisa para uma adaptação mais ampla do ser humano ao ambiente organizacional. O presente estudo teve como objetivo submeter ao teste empírico as relações entre experiências afetivas no contexto organizacional e três dimensões de bem-estar no trabalho - satisfação no trabalho, envolvimento com o trabalho e comprometimento organizacional afetivo. A amostra foi composta por 253 profissionais de uma indústria metalúrgica de autopeças na grande São Paulo, sendo 213 do sexo masculino e 29 do sexo feminino, com maior freqüência na faixa etária compreendida entre 26 a 30 anos, distribuída entre solteiros e casados. Para a coleta de dados foi utilizado um questionário de auto-preenchimento com quatro escalas que avaliaram afetos positivos e negativos, satisfação no trabalho, envolvimento com o trabalho e comprometimento organizacional afetivo. A análise dos dados foi feita por meio do SPSS, versão 16.0 e diversos sub-programas permitiram realizar análises descritivas bem como calcular modelos de regressão linear para verificar o impacto de afetos positivos e negativos sobre bem-estar no trabalho. Os resultados deste estudo revelaram que o principal preditor das dimensões de bem-estar no trabalho foram os afetos positivos. Assim, parece ser adequado afirmar que bem-estar no trabalho seja um estado psicológico sustentado, em especial, pela vivência de emoções positivas no contexto organizacional. Sugere-se que a promoção da saúde e do bem-estar dentro das organizações sejam focos de estudos futuros, representando valiosa contribuição aos campos de conhecimento da psicologia da saúde e da psicologia organizacional, bem como ao conseqüente fortalecimento dos vínculos entre empresa e trabalhadores.(AU)

Correlation between visual function and visual ability in patients with uveitis

Aim: To investigate the correlation between tests of visual function and perceived visual ability recorded with a quality of life questionnaire for patients with uveitis. Methods: 132 patients with various types of uveitis were studied. High (monocular and binocular) and low (binocular) contrast logMAR letter acuities were recorded using a Bailey-Lovie chart. Contrast sensitivity (binocular) was determined using a Pelli-Robson chart. Vision related quality of life was assessed using the Vision Specific Quality of Life (VQOL) questionnaire. Results: VQOL declined with reduced performance on the following tests: binocular high contrast visual acuity (p = 0.0011), high contrast visual acuity of the better eye (p = 0.0012), contrast sensitivity (p = 0.005), binocular low contrast visual acuity (p = 0.0065), and high contrast visual acuity of the worse eye (p = 0.015). Stepwise multiple regression analysis revealed binocular high contrast visual acuity (p <0.01) to be the only visual function adequate to predict VQOL. The age of the patient was also significantly associated with perceived visual ability (p <0.001). Conclusions: Binocular high contrast visual acuity is a good measure of how uveitis patients perform in real life situations. Vision quality of life is worst in younger patients with poor binocular visual acuity.

The effect of corneal thickness and corneal curvature on pneumatonometer measurements

Purpose. The purpose of this study was to investigate the influence of corneal topography and thickness on intraocular pressure (IOP) and pulse amplitude (PA) as measured using the Ocular Blood Flow Analyzer (OBFA) pneumatonometer (Paradigm Medical Industries, Utah, USA). Methods. 47 university students volunteered for this cross-sectional study: mean age 20.4 yrs, range 18 to 28 yrs; 23 male, 24 female. Only the measurements from the right eye of each participant were used. Central corneal thickness and mean corneal radius were measured using Scheimpflug biometry and corneal topographic imaging respectively. IOP and PA measurements were made with the OBFA pneumatonometer. Axial length was measured using A-scan ultrasound, due to its known correlation with these corneal parameters. Stepwise multiple regression analysis was used to identify those components that contributed significant variance to the independent variables of IOP and PA. Results. The mean IOP and PA measurements were 13.1 (SD 3.3) mmHg and 3.0 (SD 1.2) mmHg respectively. IOP measurements made with the OBFA pneumatonometer correlated significantly with central corneal thickness (r = +0.374, p = 0.010), such that a 10 mm change in CCT was equivalent to a 0.30 mmHg change in measured IOP. PA measurements correlated significantly with axial length (part correlate = -0.651, p < 0.001) and mean corneal radius (part correlate = +0.459, p < 0.001) but not corneal thickness. Conclusions. IOP measurements taken with the OBFA pneumatonometer are correlated with corneal thickness, but not axial length or corneal curvature. Conversely, PA measurements are unaffected by corneal thickness, but correlated with axial length and corneal radius. These parameters should be taken into consideration when interpreting IOP and PA measurements made with the OBFA pneumatonometer.

Macular pigment optical density is related to blood glutathione levels in healthy individuals

Purpose. To assess the relationship between macular pigment optical density (MPOD) and blood markers for antioxidant defense in otherwise healthy volunteers. Methods. Forty-seven healthy volunteers were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. The level of MPOD was measured using heterochromatic flicker photometry. Systemic blood pressure (BP) parameters, heart rate (HR), body mass index (BMI), and plasma levels of total, HDL, and LDL cholesterol and triglycerides (TGs) were also determined. Results. A simple correlation model revealed that the level of MPOD correlated significantly and positively with both GSH (P < 0.001) and t-GSH (P < 0.001) levels but not with those of GSSG (P > 0.05). Age, sex, systemic BP parameters, HR, BMI, and plasma levels of cholesterol and TGs did not have any influence on either MPOD or glutathione levels (all P > 0.05). In addition, a forward stepwise multiple regression analysis showed MPOD to have a significantly and independent correlation with GSH levels (ß = 0.63; P < 0.001). Conclusions. In otherwise healthy older individuals, there is a positive correlation between local and systemic antioxidant defense mechanisms.

Alzheimer's disease: the relationship between the density of senile plaques, neurofibrillary tangles and A4 protein in human patients

The numerical density of senile plaques (SP) and neurofibrillary tangles (NFT) as revealed by the Glees silver method was compared with SP and NFT revealed by the Gallyas method and with amyloid (A4) deposits in immunostained sections in 6 elderly cases of Alzheimer's disease. The density of NFT was generally greater and A4 lower in tissue from hippocampus compared with the neocortex suggesting that A4 deposition was less important than the degree of paired helical filament (PHF) related damage in the hippocampus. The density of Glees SP was positively correlated Gallyas SP weakly correlated with A4 deposit number. A stepwise multiple regression analysis which included A4 deposit and Gallyas SP density and accounted for 54% of the variation in Glees SP density. Hence, different populations of SP were revealed by the different staining methods. The results suggested that the Glees method may stain a population of SP in a region of cortex where both amyloid deposition and neurofibrillary changes have occurred.

Beta-amyloid (Abeta) deposits and blood vessels: laminar distribution in the frontal cortex of patients with Alzheimer’s disease

The laminar distribution of diffuse, primitive and classic beta-amyloid (Abeta) deposits and blood vessels was studied in the frontal cortex of patients with Alzheimer’s disease (AD). In most patients, the density of the diffuse and primitive Abeta deposits was greatest in the upper cortical layers and the classic deposits in the deeper cortical layers. The distribution of the larger blood vessels (>10 micron in diameter) was often bimodal with peaks in the upper and deeper cortical layers. The incidence of capillaries (<10 micron) was significantly higher in the deeper cortical layers in most patients. Multiple regression analysis selected vertical distance below the pia mater as the most significant factor correlated with the Abeta deposit density. With the exception of the classic deposits in two patients, there was no evidence that these vertical distributions were related to laminar variations in the incidence of large or small blood vessels.

Seasonal growth of foliose lichens in successive years in South Gwynedd, Wales

The aim of this study was to test the hypothesis that differences in the pattern of seasonal growth in foliose lichens from year to year were determined by yearly differences in the distribution of rainfall, shortwave radiation and temperature. Hence, the radial growth of Parmelia conspersa (Ehrh. Ex Ach.) Ach. , P. glabratula ssp. fuliginosa (Fr. ex Duby) Laund. and Physcia orbicularis (Neck) Poetsch. was studied on slate fragments over 34 successive months in an area of South Gwynedd, Wales. U.K. Similarities and differences were observed in the pattern of seasonal growth in the three species. Periods of maximum growth of a species occurred in different seasons in successive years. Correlation and multiple regression analysis suggested that total rainfall per month was the most important climatic variable positively correlated with monthly growth. Significant positive correlations were found in some growth periods with number of raindays per month, average wind speed and maximum and minimum temperature. Total number of sunshine hours per month and the frequency of ground frosts were negatively correlated with monthly growth in some growth periods. For each species, monthly radial growth was correlated with different climatic variables in each growth period. Hence, the results support the hypothesis in that periods of maximum growth can occur in any season in South Gwynedd and depend on (1) the distribution of periods of high total rainfall and (2) whether or not these periods coincide with periods of maximum sunlight.

The correlation between tests of visual function and perceived visual ability in central field loss patients

Purpose: To investigate the correlation between tests of visual function and perceived visual ability recorded with a 'quality-of-life' questionnaire for patients with central field loss. Method: 12 females and 7 males (mean age = 53.1 years; Range = 23 - 80 years) with subfoveal neovascular membranes underwent a comprehensive assessment of visual function. Tests included unaided distance vision, high and low contrast distance logMAR visual acuity (VA), Pelli-Robson contrast senstivity (at 1m), near logMAR word VA and text reading speed. All tests were done both monocularly and binocularly. The patients also completed a 28 point questionnaire separated into a 'core' section consisting of general questions about perceived visual function and a 'module' section with specific questions on reading function. Results: Step-wise multiple regression analysis was used to determine which visual function tests were correlated with the patients's perceived visual function and to rank them in order of importance. The visual function test that explains most of the variance in both 'core' score (66%0 and the 'module' score (68%) of the questionnaire is low contrast VA in the better eye (P<0.001 in both cases). Further, the module score also accounts for a significant proportion of the variance (P<0.01) of the distance logMAR VA in both the better and worse eye, and the near logMAR in both the better eye and binocularly. Conclusions: The best predictor of both perceived reading ability and of general perceived visual ability in this study is low contrast logMAR VA. The results highlight that distance VA is not the only relevant measure of visual fucntion in relation to a patients's perceived visual performance and should not be considered a determinant of surgical or management success.

Predicting changes in measured introcular pressure with non-contact tonometry after LASIK

Purpose: Optometrists are becoming more integrally involved in the diagnosis of and care for glaucoma patients in the UK. The correlation of apparent change in non contact tonometry (NCT) IOP measurement and change in other ocular parameters such as refractive error, corneal curvature, corneal thickness and treatment zone size (data available to optometrists after LASIK) would facilitate care of these patients. Setting: A UK Laser Eye Clinic. Methods: This is a retrospective study study of 200 sequential eyes with myopia with or without astigmatism which underwent LASIK using a Hansatome and an Alcon LADARvision 4000 excimer laser. Refraction keratometry, pachymetry and NCT IOP mesurements were taken before treatmebnt and agian 3 months after treatment. The relationship between these variables anfd teh treatment zones were studied using stepwise multiple regression analysis. Results: There was a mean difference of 5.54mmHg comnparing pre and postoperative NCT IOP. IOP change correlates with refractive error change (P < 0.001), preoperative corneal thickness (P < 0.001) and treatment zone size (P = 0.047). Preoperative corneal thickness correlates with preoperative IOP (P < 0.001) and postoperative IOP (P < 0.001). Using these correlations, the measured difference in NCT IIOP can be predicted preoperatively or postoperatively using derived equations.Conclusion: There is a significant reduction in measured NCT IOP after LASIK. The amount of reduction can be calculated using data acquired by optometrists. This is helpful for opthalmologists and optometrists who co-manage glaucoma patients who have had LASIK or with glaucoma pateints who are consideraing having LASIK.

Remote sensing applications to flood hydrology in Belize

The research compares the usefullness of four remote sensing information sources, these being LANDSAT photographic prints, LANDSAT computer compatible tapes, Metric Camera and SIR-A photographic prints. These sources provide evaluations of the catchment characteristics of the Belize and Sibun river basins in Central America. Map evaluations at 1:250,000 scale are compared to the results of the same scale, remotely sensed information sources. The values of catchment characteristics for both maps and LANDSAT prints are used in multiple regression analysis, providing flood flow formulae, after investigations to provide a suitable dependent variable discharge series are made for short term records. The use of all remotely sensed information sources in providing evaluations of catchment characteristics is discussed. LANDSAT prints and computer compatible tapes of a post flood scene are used to estimate flood distributions and volumes. These are compared to values obtained from unit hydrograph analysis, using the dependent discharge series and evaluate the probable losses from the Belize river to the floodplain, thereby assessing the accuracy of LANDSAT estimates. Information relating to flood behaviour is discussed in terms of basic image presentation as well as image processing. A cost analysis of the purchase and use of all materials is provided. Conclusions of the research indicate that LANDSAT print material may provide information suitable for regression analysis at levels of accuracy as great as those of topographic maps, that the differing information sources are uniquely applicable and that accurate estimates of flood volumes may be determined even by post flood imagery.

The appraisal and management of multi-storey dwelling blocks using large concrete panel systems

This exploratory study is concerned with the integrated appraisal of multi-storey dwelling blocks which incorporate large concrete panel systems (LPS). The first step was to look at U.K. multi-storey dwelling stock in general, and under the management of Birmingham City Council in particular. The information has been taken from the databases of three departments in the City of Birmingham, and rearranged in a new database using a suite of PC software called `PROXIMA' for clarity and analysis. One hundred of their stock were built large concrete panel system. Thirteen LPS blocks were chosen for the purpose of this study as case-studies depending mainly on the height and age factors of the block. A new integrated appraisal technique has been created for the LPS dwelling blocks, which takes into account the most physical and social factors affecting the condition and acceptability of these blocks. This appraisal technique is built up in a hierarchical form moving from the general approach to particular elements (a tree model). It comprises two main approaches; physical and social. In the physical approach, the building is viewed as a series of manageable elements and sub-elements to cover every single physical or environmental factor of the block, in which the condition of the block is analysed. A quality score system has been developed which depends mainly on the qualitative and quantitative conditions of each category in the appraisal tree model, and leads to physical ranking order of the study blocks. In the social appraisal approach, the residents' satisfaction and attitude toward their multi-storey dwelling block was analysed in relation to: a. biographical and housing related characteristics; and b. social, physical and environmental factors associated with this sort of dwelling, block and estate in general.The random sample consisted of 268 residents living in the 13 case study blocks. Data collected was analysed using frequency counts, percentages, means, standard deviations, Kendall's tue, r-correlation coefficients, t-test, analysis of variance (ANOVA) and multiple regression analysis. The analysis showed a marginally positive satisfaction and attitude towards living in the block. The five most significant factors associated with the residents' satisfaction and attitude in descending order were: the estate, in general; the service categories in the block, including heating system and lift services; vandalism; the neighbours; and the security system of the block. An important attribute of this method, is that it is relatively inexpensive to implement, especially when compared to alternatives adopted by some local authorities and the BRE. It is designed to save time, money and effort, to aid decision making, and to provide ranked priority to the multi-storey dwelling stock, in addition to many other advantages. A series of solution options to the problems of the block was sought for selection and testing before implementation. The traditional solutions have usually resulted in either demolition or costly physical maintenance and social improvement of the blocks. However, a new solution has now emerged, which is particularly suited to structurally sound units. The solution of `re-cycling' might incorporate the reuse of an entire block or part of it, by removing panels, slabs and so forth from the upper floors in order to reconstruct them as low-rise accommodations.

Uses of frontier efficiency methodologies and multi-criteria decision making for performance measurement in the energy sector

Guest editorial Ali Emrouznejad is a Senior Lecturer at the Aston Business School in Birmingham, UK. His areas of research interest include performance measurement and management, efficiency and productivity analysis as well as data mining. He has published widely in various international journals. He is an Associate Editor of IMA Journal of Management Mathematics and Guest Editor to several special issues of journals including Journal of Operational Research Society, Annals of Operations Research, Journal of Medical Systems, and International Journal of Energy Management Sector. He is in the editorial board of several international journals and co-founder of Performance Improvement Management Software. William Ho is a Senior Lecturer at the Aston University Business School. Before joining Aston in 2005, he had worked as a Research Associate in the Department of Industrial and Systems Engineering at the Hong Kong Polytechnic University. His research interests include supply chain management, production and operations management, and operations research. He has published extensively in various international journals like Computers & Operations Research, Engineering Applications of Artificial Intelligence, European Journal of Operational Research, Expert Systems with Applications, International Journal of Production Economics, International Journal of Production Research, Supply Chain Management: An International Journal, and so on. His first authored book was published in 2006. He is an Editorial Board member of the International Journal of Advanced Manufacturing Technology and an Associate Editor of the OR Insight Journal. Currently, he is a Scholar of the Advanced Institute of Management Research. Uses of frontier efficiency methodologies and multi-criteria decision making for performance measurement in the energy sector This special issue aims to focus on holistic, applied research on performance measurement in energy sector management and for publication of relevant applied research to bridge the gap between industry and academia. After a rigorous refereeing process, seven papers were included in this special issue. The volume opens with five data envelopment analysis (DEA)-based papers. Wu et al. apply the DEA-based Malmquist index to evaluate the changes in relative efficiency and the total factor productivity of coal-fired electricity generation of 30 Chinese administrative regions from 1999 to 2007. Factors considered in the model include fuel consumption, labor, capital, sulphur dioxide emissions, and electricity generated. The authors reveal that the east provinces were relatively and technically more efficient, whereas the west provinces had the highest growth rate in the period studied. Ioannis E. Tsolas applies the DEA approach to assess the performance of Greek fossil fuel-fired power stations taking undesirable outputs into consideration, such as carbon dioxide and sulphur dioxide emissions. In addition, the bootstrapping approach is deployed to address the uncertainty surrounding DEA point estimates, and provide bias-corrected estimations and confidence intervals for the point estimates. The author revealed from the sample that the non-lignite-fired stations are on an average more efficient than the lignite-fired stations. Maethee Mekaroonreung and Andrew L. Johnson compare the relative performance of three DEA-based measures, which estimate production frontiers and evaluate the relative efficiency of 113 US petroleum refineries while considering undesirable outputs. Three inputs (capital, energy consumption, and crude oil consumption), two desirable outputs (gasoline and distillate generation), and an undesirable output (toxic release) are considered in the DEA models. The authors discover that refineries in the Rocky Mountain region performed the best, and about 60 percent of oil refineries in the sample could improve their efficiencies further. H. Omrani, A. Azadeh, S. F. Ghaderi, and S. Abdollahzadeh presented an integrated approach, combining DEA, corrected ordinary least squares (COLS), and principal component analysis (PCA) methods, to calculate the relative efficiency scores of 26 Iranian electricity distribution units from 2003 to 2006. Specifically, both DEA and COLS are used to check three internal consistency conditions, whereas PCA is used to verify and validate the final ranking results of either DEA (consistency) or DEA-COLS (non-consistency). Three inputs (network length, transformer capacity, and number of employees) and two outputs (number of customers and total electricity sales) are considered in the model. Virendra Ajodhia applied three DEA-based models to evaluate the relative performance of 20 electricity distribution firms from the UK and the Netherlands. The first model is a traditional DEA model for analyzing cost-only efficiency. The second model includes (inverse) quality by modelling total customer minutes lost as an input data. The third model is based on the idea of using total social costs, including the firm’s private costs and the interruption costs incurred by consumers, as an input. Both energy-delivered and number of consumers are treated as the outputs in the models. After five DEA papers, Stelios Grafakos, Alexandros Flamos, Vlasis Oikonomou, and D. Zevgolis presented a multiple criteria analysis weighting approach to evaluate the energy and climate policy. The proposed approach is akin to the analytic hierarchy process, which consists of pairwise comparisons, consistency verification, and criteria prioritization. In the approach, stakeholders and experts in the energy policy field are incorporated in the evaluation process by providing an interactive mean with verbal, numerical, and visual representation of their preferences. A total of 14 evaluation criteria were considered and classified into four objectives, such as climate change mitigation, energy effectiveness, socioeconomic, and competitiveness and technology. Finally, Borge Hess applied the stochastic frontier analysis approach to analyze the impact of various business strategies, including acquisition, holding structures, and joint ventures, on a firm’s efficiency within a sample of 47 natural gas transmission pipelines in the USA from 1996 to 2005. The author finds that there were no significant changes in the firm’s efficiency by an acquisition, and there is a weak evidence for efficiency improvements caused by the new shareholder. Besides, the author discovers that parent companies appear not to influence a subsidiary’s efficiency positively. In addition, the analysis shows a negative impact of a joint venture on technical efficiency of the pipeline company. To conclude, we are grateful to all the authors for their contribution, and all the reviewers for their constructive comments, which made this special issue possible. We hope that this issue would contribute significantly to performance improvement of the energy sector.

Plasma irisin levels predict telomere length in healthy adults

The ageing process is strongly influenced by nutrient balance, such that modest calorie restriction (CR) extends lifespan in mammals. Irisin, a newly described hormone released from skeletal muscles after exercise, may induce CR-like effects by increasing adipose tissue energy expenditure. Using telomere length as a marker of ageing, this study investigates associations between body composition, plasma irisin levels and peripheral blood mononuclear cell telomere length in healthy, non-obese individuals. Segmental body composition (by bioimpedance), telomere length and plasma irisin levels were assessed in 81 healthy individuals (age 43∈±∈15.8 years, BMI 24.3∈±∈2.9 kg/m2). Data showed significant correlations between log-transformed relative telomere length and the following: age (p∈<∈0.001), height (p∈=∈0.045), total body fat percentage (p∈=∈0.031), abdominal fat percentage (p∈=∈0.038) , visceral fat level (p∈<∈0.001), plasma leptin (p∈=∈0.029) and plasma irisin (p∈=∈0.011), respectively. Multiple regression analysis using backward elimination revealed that relative telomere length can be predicted by age (b∈=∈-0.00735, p∈=∈0.001) and plasma irisin levels (b∈=∈0.04527, p∈=∈0.021). These data support the view that irisin may have a role in the modulation of both energy balance and the ageing process. © 2014 The Author(s).