Showing papers by "City University London published in 2003"
TL;DR: The rod–cone and melanopsin systems together seem to provide all of the photic input for these accessory visual functions such as pupillary light reflex and circadian photo-entrainment.
Abstract: In the mammalian retina, besides the conventional rod-cone system, a melanopsin-associated photoreceptive system exists that conveys photic information for accessory visual functions such as pupillary light reflex and circadian photo-entrainment. On ablation of the melanopsin gene, retinal ganglion cells that normally express melanopsin are no longer intrinsically photosensitive. Furthermore, pupil reflex, light-induced phase delays of the circadian clock and period lengthening of the circadian rhythm in constant light are all partially impaired. Here, we investigated whether additional photoreceptive systems participate in these responses. Using mice lacking rods and cones, we measured the action spectrum for phase-shifting the circadian rhythm of locomotor behaviour. This spectrum matches that for the pupillary light reflex in mice of the same genotype, and that for the intrinsic photosensitivity of the melanopsin-expressing retinal ganglion cells. We have also generated mice lacking melanopsin coupled with disabled rod and cone phototransduction mechanisms. These animals have an intact retina but fail to show any significant pupil reflex, to entrain to light/dark cycles, and to show any masking response to light. Thus, the rod-cone and melanopsin systems together seem to provide all of the photic input for these accessory visual functions.
1,112 citations
TL;DR: A needs satisfaction measure of QoL in early old age, which has four ontologically grounded domains: control, autonomy, pleasure, and self-realization, which appears to be a useful scale for measuring quality of life in older people.
Abstract: Quality of life is the subject of much research. However it lacks an agreed theoretical basis. In studies with older populations(ill) health has been used as a proxy measure for quality of life (QoL). We have developed a needs satisfaction measure of QoL in early old age. Our measure has four ontologically grounded domains: conal, autonomy, pleasure, and self-realization. The measure was piloted with focus groups, a self-completion pilot, and cognitive interview testing. This produced a 22-item scale that was included in a postal questionnaire and sent to 286 people aged 65-75 years.A 92% response rate was achieved. The scale was reduced to 19 items on the basis of statistical analysis. The domains have Cronbach's alphas between 0.6 and 0.8. Correlations between the four domains range from 0.4 to 0.7. A second order factor analysis revealed a single latent QoL factor. The scores for the 19-item scale are well distributed along the range although they exhibit a slight negative skew. Concurrent validity was assessed using the Life Satisfaction Index--wellbeing. A strong and positive association was found between the two scales (r= 0.6, p = 0.01). The CASP-19 appears to be a useful scale for measuring QoL in older people.
783 citations
TL;DR: This contribution reports how a European set of general population preference weights was derived from the data collected in the 11 valuation studies to suggest that VAS values for EQ-5D health states in six Western European countries can be described by a common model
Abstract: The EQ-5D questionnaire is a widely used generic instrument for describing and valuing health that was developed by the EuroQol Group. A primary objective of the EuroQol Group is the investigation of values for health states in the general population in different countries. As part of the EuroQol enterprise 11 population surveys were carried out in six Western European countries (Finland, Germany, The Netherlands, Spain, Sweden and the UK) to value health states as defined by the EQ-5D using a standardised visual analogue scale (EQ-5D VAS). This contribution reports how a European set of general population preference weights was derived from the data collected in the 11 valuation studies. The scores from this set of preference weights can be applied to generate a VAS-based weighted health status index for all the potential 243 EQ-5D health states for use in multi-national studies. To estimate the preference weights a multi-level regression analysis was performed on 82,910 valuations of 44 EQ-5D health states elicited from 6,870 respondents. Stable and plausible solutions were found for the model parameters. The R(2) value was 75%. The analysis showed that the major source of variance, apart from 'random error', was variance between individuals (28.3% of the total residual variance). These results suggest that VAS values for EQ-5D health states in six Western European countries can be described by a common model.
434 citations
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TL;DR: In this article, the authors found that middle managers fulfil a complex "change intermediary" position during implementation and that a key aspect of this position is the need for middle managers to engage in a range of activities to aid their interpretation of the change intent, which then informs the personal changes they attempt to undertake, how they help others through change, and what changes they implement in their departments.
Abstract: Middle managers have been under attack as organizational downsizing and reengineering have reduced their number They are also frequently portrayed as obstructive and resistant to change However, recent research suggests that managers at middle levels in organizations may be able to make a strategic contribution Data from research on how managers in an organization undergoing transformation experience change are used to build on this existing research to demonstrate that middle managers fulfil a complex 'change intermediary' position during implementation The findings reveal that a key aspect of this position is the need for middle managers to engage in a range of activities to aid their interpretation of the change intent This interpretation activity then informs the personal changes they attempt to undertake, how they help others through change, how they keep the business going during the transition and what changes they implement in their departments The interpretation aspect of their role is often overlooked, leading to workload issues and role conflict These findings offer an alternative perspective on perceived middle manager resistance and lead into suggestions for future research and organizational implications
433 citations
TL;DR: The SAQOL-39 is an acceptable, reliable, and valid measure of HRQL in people with long-term aphasia and its usefulness in evaluative research and routine clinical practice is investigated.
Abstract: Background and Purpose— Health-related quality of life (HRQL) is a key outcome in stroke clinical trials. Stroke-specific HRQL scales (eg, SS-QOL, SIS) have generally been developed with samples of stroke survivors that exclude people with aphasia. We adapted the SS-QOL for use with people with aphasia to produce the Stroke and Aphasia Quality of Life Scale (SAQOL). We report results from the psychometric evaluation of the initial 53-item SAQOL and the item-reduced SAQOL-39. Methods— We studied 95 people with long-term aphasia to evaluate the acceptability, reliability, and validity of the SAQOL and SAQOL-39 using standard psychometric methods. Results— A total of 83 of 95 (87%) were able to complete the SAQOL by self-report; their results are reported here. Results supported the reliability and validity of the overall score on the 53-item SAQOL, but there was little support for hypothesized subdomains. Using factor analysis, we derived a shorter version (SAQOL-39) that identified 4 subdomains (physical, ...
387 citations
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TL;DR: The authors discusses three particularly promising approaches (interactive discussion groups, self-reports, and practitioner-led research) that fit the increasingly disparate research paradigms now being used to understand strategizing and other management issues.
Abstract: Empirical studies of strategizing face contradictory pressures. Ethnographic approaches are attractive, and typically expected since we need to collect data on strategists and their practices within context. We argue, however, that today's large, multinational, and highly diversified organizational settings require complimentary methods providing more breadth and flexibility. This paper discusses three particularly promising approaches (interactive discussion groups, self-reports, and practitioner-led research) that fit the increasingly disparate research paradigms now being used to understand strategizing and other management issues. Each of these approaches is based on the idea that strategizing research cannot advance significantly without reconceptualizing frequently taken-for-granted assumptions about the way to do research and the way we engage with organizational participants. The paper focuses in particular on the importance of working with organizational members as research partners rather than passive informants.
286 citations
TL;DR: In this paper, the authors studied the impact of bank concentration, regulations, and national institutions on the likelihood of suffering a systemic banking crisis using data on 79 countries over the period 1980-97, and found that crises are less likely in more concentrated banking systems, in countries with fewer regulatory restrictions on bank competition and activities, and in economies with better institutions.
Abstract: The authors study the impact of bank concentration, regulations, and national institutions on the likelihood of suffering a systemic banking crisis. Using data on 79 countries over the period 1980-97, they find that crises are less likely (1) in more concentrated banking systems, (2) in countries with fewer regulatory restrictions on bank competition and activities, and (3) in economies with better institutions, that is, institutions that encourage competition and support private property rights.
286 citations
TL;DR: The quality of parent-child relationships and the socioemotional and gender development of a community sample of 7-year-old children with lesbian parents is examined and findings are in line with those of earlier investigations showing positive mother-child relationship and well-adjusted children.
Abstract: Existing research on children with lesbian parents is limited by reliance on volunteer or convenience samples. The present study examined the quality of parent-child relationships and the socioemotional and gender development of a community sample of 7-year-old children with lesbian parents. Families were recruited through the Avon Longitudinal Study of Parents and Children, a geographic population study of 14,000 mothers and their children. Thirty-nine lesbian-mother families, 74 two-parent heterosexual families, and 60 families headed by single heterosexual mothers were compared on standardized interview and questionnaire measures administered to mothers, co-mothers/fathers, children, and teachers. Findings are in line with those of earlier investigations showing positive mother-child relationships and well-adjusted children.
285 citations
TL;DR: It is suggested that psychological outcomes in women with CAIS are similar to those in other women, and additional attention to more detailed aspects of psychological well-being in CAIS is needed.
Abstract: We evaluated psychological outcomes and gender development in 22 women with complete androgen insensitivity syndrome (CAIS). Participants were recruited through a medical database (n = 10) or through a patient support group (n = 12). Controls included 14 males and 33 females, of whom 22 were matched to women with CAIS for age, race, and sex-of-rearing. Outcome measures included quality of life (self-esteem and psychological general well-being), gender-related psychological characteristics (gender identity, sexual orientation, and gender role behavior in childhood and adulthood), marital status, personality traits that show sex differences, and hand preferences. Women recruited through the database versus the support group did not differ systematically, and there were no statistically significant differences between the 22 women with CAIS and the matched controls for any psychological outcome. These findings argue against the need for two X chromosomes or ovaries to determine feminine-typical psychological development in humans and reinforce the important role of the androgen receptor in influencing masculine-typical psychological development. They also suggest that psychological outcomes in women with CAIS are similar to those in other women. However, additional attention to more detailed aspects of psychological well-being in CAIS is needed.
275 citations
TL;DR: It is speculated that, although androgen may influence targeting abilities prenatally, if hormones influence the development of mental rotations ability, they do so at some other time, perhaps during the first six months of postnatal life.
228 citations
TL;DR: A new approach to forecasting evaluation is devised, a predictive error-forecasting model which compares and evaluates forecasting methods based on their factor levels when faced with intermittent demand, and confirms the continued superiority of the weighted moving average, Holt and Croston method for intermittent demand.
TL;DR: In this paper, a reinterpretation of the model underpinning the Lee-Carter methodology for forecasting mortality (and other vital) rates is introduced, and a parallel methodology based on generalized linear modelling is introduced.
Abstract: Summary. The paper presents a reinterpretation of the model underpinning the Lee-Carter methodology for forecasting mortality (and other vital) rates. A parallel methodology based on generalized linear modelling is introduced.The use of residual plots is proposed for both methods to aid the assessment of the goodness of fit. The two methods are compared in terms of structure and assumptions. They are then compared through an analysis of the gender- and age-specific mortality rates for England and Wales over the period 1950-1998 and through a consideration of the forecasts generated by the two methods. The paper also compares different approaches to the forecasting of life expectancy and considers the effectiveness of the Coale-Guo method for extrapolating mortality rates to the oldest ages.
TL;DR: A number of guanidines have been identified in this paper that could be usefully pursued as part of combination chemotherapy along with the alkylphosphocholines and further research is needed on more effective combination chemotherapy.
Abstract: A reliable figure for the expected incidence of Acanthamoeba keratitis of one per 30000 contact lens wearers per year has now been obtained from a combination of three cohort and three Questionnaire Reporting Surveys; 88% of cases wore hydrogel lenses and 12% wore rigid lenses This figure now provides a basis for the expected number of cases against which to judge either epidemic outbreaks or effects of prevention with disinfecting solutions, better hygiene, or the use of disposable lenses Molecular biology of Acanthamoeba has advanced considerably in the last 10 years with new automated sequencing technology This has allowed the construction of a genotype identification scheme with 13 different genotypes against which to compare clinical isolates for epidemiological investigations or pathogenicity markers So far, only four genotypes have been associated with keratitis of which the majority have been T4 but T3, T6, and T11 have each caused individual cases Each genotype is heterogenous and can be further subdivided by comparison of sequences of diagnostic fragments of 18S rDNA, riboprinting by PCR-RFLP of 18S rDNA, or by mitochondrial DNA RFLP Drug therapy has been revolutionised with the introduction of the biguanides-chlorhexidine or polyhexamethylene biguanide-with most but not all infections quickly resolving Failure can still occur occasionally and further research is needed on more effective combination chemotherapy A number of guanidines have been identified in this paper that could be usefully pursued as part of combination chemotherapy along with the alkylphosphocholines
TL;DR: In this article, the authors consider the special pressures on middle managers to tell stories about their organization that make sense to three different audiences; their superiors, their subordinates and themselves, and suggest why these characteristics may be debilitating for middle management practice.
Abstract: This article seeks to illuminate our understanding of the lives of middle managers by considering the special pressures on them to tell stories about their organization that make sense to three different audiences; their superiors, their subordinates and themselves. Each of those audiences will demand to hear a convincing account, but the senior audience may trample unaware on middle managers’ stories, the junior audience may view them with scepticism or hostility, and the self audience may be fearful of losing the plot. Illustrated by four middle management storytelling situations, the article offers a narrative understanding of the peculiar loneliness, precariousness and vulnerability that characterize middle management, and suggests why these characteristics may be debilitating for middle management practice.
TL;DR: It appears that PPV offers protection against IPD in the general elderly population whereas it has a moderate effect in the high-risk elderly, and the vaccine has little or no effect against pneumonia.
Abstract: A 23-valent polysaccharide pneumococcal vaccine (PPV) has been available in the UK for more than 20 years and is currently recommended for use in high-risk groups (HRG) of 2+ years of age. The degree of protection afforded by the PPV remains a critical issue, although a number of randomised clinical trials and case-control studies (CCS) have been published. The aim of this work is to review the estimates on the efficacy of PPV against pneumococcal pneumonia and invasive pneumococcal disease (IPD) in the elderly and to perform a meta-analysis in order to obtain a pooled estimate of the level of protection in high and low risk individuals. These two groups of individuals are at the centre of the current debate on whether or not to extend the vaccination programme to all elderly individuals 65+. Only randomised and quasi-randomised studies are included in the analysis and results are compared with previous meta-analyses. The effect of the inclusion of observational studies is investigated in the sensitivity analysis. When taken with the results of other meta-analyses and observational studies, it appears that PPV offers protection against IPD in the general elderly population (VE = 65%; 95% CI: -49-92%) whereas it has a moderate effect in the high-risk elderly (VE = 20%; 95% CI: -188-78%). The vaccine has little or no effect against pneumonia (VE = 16% in the general elderly and -20% in HRG).
TL;DR: In both courts, a simple heuristic proved to be a better predictor of judicial decisions than a more complex model that instantiated the principles of due process.
Abstract: People are often expected to make decisions based on all of the relevant information, weighted and combined appropriately. Under many conditions, however, people use heuristic strategies that depart from this ideal. I tested the ability of two models to predict bail decisions made by judges in two courts. In both courts, a simple heuristic proved to be a better predictor of judicial decisions than a more complex model that instantiated the principles of due process. Specifically, judges were "passing the buck" because they relied on decisions made by the police, prosecution, and previous bench. Problematically, these earlier decisions were not significantly related to case characteristics. These findings have implications for the types of models researchers use to capture professional decision-making policies.
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TL;DR: In this article, a literature-based portfolio model was developed including 17 innovation-determining factors, related to the firm's technical, market, human resource and organisational competencies.
Abstract: This paper investigates the 'importance' and 'awareness' of firm-specific competencies as determinants of technological innovation in the context of a European newly industrialised country. A literature-based portfolio model was developed including 17 established innovation-determining factors, related to the firm's technical, market, human resource and organisational competencies. The 'importance' of those factors as determinants of innovation in the Greek industry was tested with a survey of 105 manufacturing firms. Using correlation and regression analyses the author classified the competencies into 'major importance', 'moderate importance' and 'unimportant' ones. 'Major importance' determinants of innovation included the intensity of R&D, strength in marketing, proportion of university graduates and engineers in the staff, proportion of staff with managerial responsibility, proportion of professional staff with previous experience in another company and incentives offered to the employees to contribute to innovation. The 'awareness' of the important competencies differentiating Greek innovative companies was tested by comparing the above 'objective' results with the perceptions of the responding managers. The perceptual analysis confirmed the importance of the statistically-driven variables at the aggregated level. At the level of the individual variables, a number of inconsistencies were identified. The managers overestimated the importance of international work experience of professional staff and of training and underestimated the importance of the potential contribution of shop-floor employees. Relating the results to the Greek institutional context, the study's general finding was that the important determinants of innovation were scarce in the Greek business environment. The highly innovative companies were the ones to overcome country-specific innovation barriers, such as negligible industrial R&D, general weakness in marketing, outdated educational system, limited labour mobility and cultural problems with involving shop-floor employees in the innovation process.
TL;DR: It was found that surrogate mothers do not generally experience major problems in their relationship with the commissioning couple, in handing over the baby, or from the reactions of those around them.
Abstract: BACKGROUND: This study examined the motivations, experiences and psychological consequences of surrogacy for surrogate mothers. METHODS: Thirty-four women who had given birth to a surrogate child approximately 1 year previously were interviewed by trained researchers, and the data rated using standardized coding criteria. Information was obtained on: (i) reasons for the woman’s decision to become a surrogate mother; (ii) her retrospective view of the relationship with the commissioning couple before the pregnancy, during the pregnancy, and after the birth; (iii) her experiences during and after relinquishing the child; and (iv) how others reacted to her decision to become a surrogate mother. RESULTS: It was found that surrogate mothers do not generally experience major problems in their relationship with the commissioning couple, in handing over the baby, or from the reactions of those around them. The emotional problems experienced by some surrogate mothers in the weeks following the birth appeared to lessen over time. CONCLUSIONS: Surrogate mothers do not appear to experience psychological problems as a result of the surrogacy arrangement.
TL;DR: The objective of this study was to provide a complete picture of the pre‐vaccine epidemiology of the Varicella‐Zoster Virus in England and Wales to aid in the design of immunisation programs.
Abstract: Many countries are studying currently the possibility of mass vaccination against varicella. The objective of this study was to provide a complete picture of the pre-vaccine epidemiology of the Varicella-Zoster Virus in England and Wales to aid in the design of immunisation programs. Population-based data including general practitioner sentinel surveillance, hospitalisation data, and death certificates from England and Wales were analysed. The average incidence rates for varicella and zoster between 1991 and 2000 were 1,291 and 373 per 100,000 years, respectively. Overall hospitalisation rates were equal for varicella and zoster (4.5 vs. 4.4 hospitalisation per 100,000 population) with 5 and 8%, respectively, having underlying immunosuppressive conditions. The age-specific proportion of cases hospitalised and length of stay were similar between the two diseases. However, the overall burden of disease is considerably higher for zoster. The number of inpatient days and case-fatality due to zoster are roughly 4 to 6 times greater than for varicella (11 vs. 3 days and 25 vs. 4 deaths per 100,000 case). These results provide base-line estimates should mass varicella vaccination be introduced in England and Wales.
TL;DR: The model predicts that, although an upward shift in the age at infection occurs, the overall morbidity due to varicella is likely to decrease following mass infant vaccination, and, on the other hand, cases of zoster may significantly increase in the first 50 years following vaccination.
Abstract: In 1995, varicella vaccination was introduced into the infant immunization schedule of the United States. Currently, many other countries are considering mass varicella vaccination. Mass vaccination has two dangers: it could increase the number of varicella cases in adults, where severity is greater, and increase cases of zoster. A deterministic, realistic, age-structured model (RAS) was built to study these concerns. Model parameter estimates were derived from a review of the literature and surveillance data from England and Wales. Different vaccine efficacy scenarios, vaccine coverages, and vaccination strategies were investigated. The model predicts that, although an upward shift in the age at infection occurs, the overall morbidity due to varicella is likely to decrease following mass infant vaccination. On the other hand, cases of zoster may significantly increase in the first 50 years following vaccination. The model predicts that, in a population similar to England and Wales (50 m people), varicella vaccination with 90% coverage would prevent 0.6 m inpatient days due to varicella but would generate an extra 1.1 m inpatient days due to zoster over the first 65 years. Thus, under base-case model assumptions, the gain in reduction of varicella morbidity from infant vaccination is offset in the short-term by the increases in zoster morbidity (using inpatient days as a proxy). Paradoxically, less effective vaccines or vaccine programmes can be more effective in reducing overall morbidity (varicella + zoster) by allowing the virus to circulate more, which produces a smaller shift in the age at infection and a smaller increase in zoster cases.
TL;DR: In this paper, the authors examined the variability of interest and non-interest income, and their correlation, for the banking systems of EU countries for the years 1994-98, and found that the increased importance of noninterest income did, for most but not all categories of bank, stabilise profits in the European banking industry in those years.
Abstract: Banks can differ markedly in their sources of income. Some focus on business lending, some on household lending, and some on fee-earning activities. Increasingly, however, most banks are diversifying into fee-earning activities. Such diversification is either justified (by the bank) or welcomed (by commentators), or both, as reducing the bank's exposure to risk. Diversification across various sources of earnings is welcomed for, it is claimed, diversification reduces risk. Whether it does of course depends on how independent of each other the various earnings sources are. Traditionally fee income has been very stable; but, also traditionally, it has been a small part of the earnings stream of most banks. Has non-interest income remained stable, or at least uncorrelated with interest income, as banks have increased its importance in their earnings? This paper examines the variability of interest and non-interest income, and their correlation, for the banking systems of EU countries for the years 1994-98. It is found that the increased importance of non-interest income did, for most but not all categories of bank, stabilise profits in the European banking industry in those years. It is not, however, invariably more stable than interest income.
TL;DR: In this article, the authors study the determinants of mergers and acquisitions around the world by focusing on differences in laws and regulation across countries and find that the volume of M&A activity is significantly larger in countries with better accounting standards and stronger shareholder protection.
Abstract: We study the determinants of mergers and acquisitions around the world by focusing on differences in laws and regulation across countries. We find that the volume of M&A activity is significantly larger in countries with better accounting standards and stronger shareholder protection. The probability of an all-cash bid decreases with the level of shareholder protection in the acquirer country. In cross-border deals targets are typically from countries with poorer investor protection than acquirers, suggesting that cross-border transactions play a governance role by improving the degree of investor protection within target firms.
TL;DR: In this article, the authors evaluate the impact of a creative arts program aimed at socially excluded youth, which has been developed in partnership by the Royal National Theatre and the London boroughs of Lewisham and Greenwich funded by SRB6.
Abstract: Arts projects have become an important part of community development strategies. In addition to any creative achievements, projects are expected to have positive and measurable impacts on local social capital. Evidence for this is routinely demanded by funding organisations, and formal evaluations of projects have become a condition of investment. However, quantifying the impact of the arts in terms of social gain presents considerable difficulties, arguably greater than in any other field of evaluation. These problems are not just methodological. They also raise the question of the extent to which creative processes can or should be managed and controlled. This paper discusses these issues and reviews evaluations of community based arts programmes. abc http://www.barnardos.org.uk/resources 2 The value of the arts to community development Cultural and artistic programmes have played an increasingly prominent role in urban regeneration initiatives in the United Kingdom since the mid-1980's (Landry and Matarasso, 1996; Braden and Mayo, 1999). While a national policy on impact evaluation in the arts is not yet a reality (Shaw, 1999), in community development work, a quid pro quo is increasing expected as a condition for investment. Where arts programmes benefit from statutory funding, outcomes expected are frequently linked to social gain (National Foundation for Educational Research, 2000; Department of Health, 2001). The UK government's Social Exclusion Unit has reported on the role of arts, sport and leisure. A key finding was that supporting participation in arts and sport can aid neighbourhood renewal through improved performance on indicators of health, crime, employment and education (Department for Culture, Media and Sport, 1999). Within this context, an emphasis on robust evaluation as a condition of funding has developed, particularly in exploring the extent to which arts investment is directed at specific populations held to be in need (Arts Council for England, 2000; Jermyn, 2001). In other words, community development programmes that utilise the arts must assure investors that they can add value by achieving measurable outcomes associated with social gain. Barnardo's, the UK's largest children's charity, is evaluating the impact of a creative arts programme aimed at socially excluded youth, which has been developed in partnership by the Royal National Theatre and the London boroughs of Lewisham and Greenwich funded thorough SRB6. Targeting young people aged seven to 26 from areas of high deprivation, its objectives are to improve employment and educational prospects, promote sustainable regeneration and reduce social exclusion (Royal National Theatre 2000). As part of this process of evaluation, a literature review was undertaken to explore the extent to which community based arts projects have achieved identifiable social gains. abc http://www.barnardos.org.uk/resources
TL;DR: The concept of measurement is defined as a process of empirical, objective assignment of symbols to attributes of objects and events of the real world, in such a way as to describe them as discussed by the authors.
TL;DR: The authors found significant survivorship bias in estimates of the standard deviation, skewness, and kurtosis of individual hedge fund returns, which will lead investors to seriously overestimate the benefits of hedge funds.
Abstract: Hedge funds exhibit a high rate of attrition that has increased substantially over time. Lack of size, lack of performance and an increasingly aggressive attitude of old and new fund managers alike appear to be the main factors behind this phenomenon. Although attrition is high, survivorship bias in hedge fund data is modest, which reflects the relatively small difference in performance between surviving and defunct funds. Concentrating on survivors only will overestimate the average hedge fund return by around 2% per annum. For small, young, and leveraged funds, however, the bias can be as high as 4%–5%. The authors also find significant survivorship bias in estimates of the standard deviation, skewness, and kurtosis of individual hedge fund returns. When not corrected for, this will lead investors to seriously overestimate the benefits of hedge funds. Fund of funds attrition is much lower. Combined with the small difference in performance between surviving and defunct funds of
funds, this yields relatively low survivorship bias estimates for funds of funds.
TL;DR: Analysis showed little difference between form and type of self-reported imagery and divergent thinking, and explanations for the failure to account for more than 3% of the variance in the data sets are discussed in the context of anecdotal reports, task validity, and design problems.
Abstract: The reports of many creative individuals suggest the use of mental imagery in scientific and artistic production. A variety of protocols have tested the association between mental imagery and creativity, but the individual differences approach has been most frequently employed. This approach is assessed here through a range of meta-analytic tests. Database searches revealed 18 papers employing the individual differences approach that were subjected to a conservative set of selection criteria. Nine studies (1494 participants) were included in the final analyses. A marginal, but statistically significant, Fisher's Z-transformed correlation coefficient was revealed. Further analyses showed little difference between form and type of self-reported imagery and divergent thinking. Explanations for the failure to account for more than 3% of the variance in the data sets are discussed in the context of anecdotal reports, task validity, and design problems.
TL;DR: Two experts are asked to debate the proposition that psychological debriefing is a waste of time and what of the concerns that it may lead to long-term problems?
Abstract: People who experience serious traumatic events may become distressed and are at risk of developing psychological illness. Because of the perceived need to ease the distress and to prevent chronicity, various forms of psychological therapy have been deployed. One such therapy is psychological
TL;DR: In this paper, five main perspectives on family-friendly management are differentiated by their conceptions about the nature of such management and not just by its assumed predictors Multivariate analysis of the relationships among a set of family-oriented practices shows that some but not all are used in a systematic way.
Abstract: Five main perspectives on family-friendly management are differentiated by their conceptions about the nature of such management and not just by its assumed predictors Multivariate analysis of the relationships among a set of family-oriented practices shows that some but not all are used in a systematic way Regression analysis reveals that employers’ adoption of family-friendly approaches is explained by factors that span all five perspectives, but overall, the organizational adaptation perspective fares best
TL;DR: In this paper, a study of families with a child created through a surrogacy arrangement was conducted and the authors focused on the commissioning couples' reports of their experiences and found that most couples had considered surrogacy only after a long period of infertility or when it was the only option available.
Abstract: BACKGROUND: Findings are presented of a study of families with a child created through a surrogacy arrangement. This paper focuses on the commissioning couples’ reports of their experiences. METHODS: A total of 42 couples with a 1-year-old child born through surrogacy were assessed using a standardized semi-structured interview. Data were obtained on motivations for surrogacy, details about the surrogate mother, experience of surrogacy during pregnancy and after birth and disclosure of the surrogacy to friends and family. RESULTS: Couples had considered surrogacy only after a long period of infertility or when it was the only option available. Couples retrospectively recalled their levels of anxiety throughout the pregnancy as low, and relationships between the couple and the surrogate mother were found to be generally good. This was the case regardless of whether or not the couple had known the surrogate mother prior to the arrangement. After the birth of the child, positive relations continued with the large majority of couples maintaining some level of contact with the surrogate mother. All couples had told family and friends about the surrogacy and were planning to tell the child. CONCLUSIONS: Commissioning couples generally perceived the surrogacy arrangement as a positive experience.
TL;DR: In normal eyes, the Longitudinal Chromatic Aberration of the Indiana Chromatic Eye Model can predict the defocus term changes measured experimentally, although the intersubject variability could not be neglected.
Abstract: Purpose. In most current aberrometers, near infrared light is used to measure ocular aberrations, whereas in some applications, optical aberration data in the visible range are required. We compared optical aberration measurements using infrared (787 nm) and visible light (543 nm) in a heterogeneous group of subjects to assess whether aberrations are similar in both wavelengths and to estimate experimentally the ocular chromatic focus shift. Methods. Ocular aberrations were measured in near infrared and visible light using two different laboratory-developed systems: laser ray tracing (LRT) and Shack-Hartmann. Measurements were conducted on 36 eyes (25 and 11 eyes, respectively), within a wide range of ages (20 to 71 years), refractive errors (6.00 to 16.50), and optical quality (root mean square wavefront error, excluding defocus, from 0.40 to 9.89 m). In both systems, wave aberrations were computed from the ray aberrations by modal fitting to a Zernike polynomial base (up to seventh order in laser ray tracing and sixth order in Shack-Hartmann). We compared the Zernike coefficients and the root mean square wavefront error corresponding to different terms between infrared and green illumination. Results. A Student's t-test performed on the Zernike coefficients indicates that defocus was significantly different in all of the subjects but one. Average focus shift found between 787 nm and 543 nm was 0.72 D. A very small percentage of the remaining coefficients was found to be significantly different: 4.7% of the 825 coefficients (25 eyes with 33 terms) for laser ray tracing and 18.2% of the 275 coefficients (11 eyes with 25 terms) for Shack-Hartmann. Astigmatism was statistically different in 8.3% of the eyes, root mean square wavefront error for third-order aberrations in 16.6%, and spherical aberration (Z4 0 ) in 11.1%. Conclusions. Aerial images captured using infrared and green light showed noticeable differences. Apart from defocus, this did not affect centroid computations because within the variability of the techniques, estimates of aberrations with infrared were equivalent to those measured with green. In normal eyes, the Longitudinal Chromatic Aberration of the Indiana Chromatic Eye Model can predict the defocus term changes measured experimentally, although the intersub- ject variability could not be neglected. The largest deviations from the prediction were found on an aphakic eye and on the oldest subject. (Optom Vis Sci 2003;80:26-35)