The optimum prepaid monetary incentives for mail surveys

Increasing mail-survey response using monetary incentives is a proven, but not always cost-effective method in every population. This paper tackles the questions of whether it is worth using monetary incentives and the size of the inducement by testing a logit model of the impact of prepaid monetary incentives on response rates in consumer and organizational mail surveys. The results support their use and show that the inducement value makes a significant impact on the effect size. Importantly, no significant differences were found between consumer and organizational populations. A cost-benefit model is developed to estimate the optimum incentive when attempting to minimize overall survey costs for a given sample size. © 2006 Operational Research Society Ltd. All rights reserved.

Public capital and total factor productivity:new evidence from the Italian regions, 1970-98

This paper analyses the relationship between industrial total factor productivity and public capital across the 20 Italian administrative regions. It adds upon the existing literature in a number of ways: it analyses a longer period (1970-98); it allows for the role of human capital accumulation; it tests for the existence of a long-run relationship between total factor productivity and public capital (through previously suggested panel techniques) and for weak exogeneity of public capital; and it assesses the significance of public capital within a non-parametric set-up based on the Free Disposal Hull. The results confirm that public capital has a significant impact on the evolution of total factor productivity, particularly in the Southern regions. This impact is mainly ascribed to the core infrastructures (road and airports, harbours, railroads, water and electricity, telecommunications). Also, core infrastructures are weakly exogenous. © 2005 Regional Studies Association.

Perceptual differences of marketing journals:a worldwide perspective

The practice of evaluating faculty and business schools based on their journal publications has increased the emphasis on research output in peer reviewed journals. Since journal standings are a frequently debated issue, this study seeks to examine the perceptual differences of journals between different segments of marketing academics. Based on a worldwide online survey, journals are assessed in terms of four subjective quality metrics: journal familiarity, average rank position, percent of respondents who classify a journal as top tier, and readership. It is demonstrated that an individual's geographic origin, research interests or journal affiliation can have a significant impact on journal rankings.

How do statisticians perceive statistics journals?

Since researchers and academic institutions are increasingly evaluated based on their publication record in peer reviewed journals, it is crucial to assess how the statistics community perceives statistics journals. This study presents four subjective quality metrics of statistics journals as expressed by different segments of statisticians. Based on a worldwide sample of 2,190 statisticians, our findings indicate that the research interest and geographic origin of the researcher have a significant impact on journal perceptions, which are highly correlated with a journal's total number of citations.

Prevalence of the use of cancer related self-tests by members of the public:A community survey

Background: Self-tests are those where an individual can obtain a result without recourse to a health professional, by getting a result immediately or by sending a sample to a laboratory that returns the result directly. Self-tests can be diagnostic, for disease monitoring, or both. There are currently tests for more than 20 different conditions available to the UK public, and self-testing is marketed as a way of alerting people to serious health problems so they can seek medical help. Almost nothing is known about the extent to which people self-test for cancer or why they do this. Self-tests for cancer could alter perceptions of risk and health behaviour, cause psychological morbidity and have a significant impact on the demand for healthcare. This study aims to gain an understanding of the frequency of self-testing for cancer and characteristics of users. Methods: Cross-sectional survey. Adults registered in participating general practices in the West Midlands Region, will be asked to complete a questionnaire that will collect socio-demographic information and basic data regarding previous and potential future use of self-test kits. The only exclusions will be people who the GP feels it would be inappropriate to send a questionnaire, for example because they are unable to give informed consent. Freepost envelopes will be included and non-responders will receive one reminder. Standardised prevalence rates will be estimated. Discussion: Cancer related self-tests, currently available from pharmacies or over the Internet, include faecal occult blood tests (related to bowel cancer), prostate specific antigen tests (related to prostate cancer), breast cancer kits (self examination guide) and haematuria tests (related to urinary tract cancers). The effect of an increase in self-testing for cancer is unknown but may be considerable: it may affect the delivery of population based screening programmes; empower patients or cause unnecessary anxiety; reduce costs on existing healthcare services or increase demand to investigate patients with positive test results. It is important that more is known about the characteristics of those who are using self-tests if we are to determine the potential impact on health services and the public. © 2006 Wilson et al; licensee BioMed Central Ltd.

Military spending and economic growth in South Africa

This paper undertakes an empirical analysis of the economic effects of military spending on the South African economy. It estimates a neo-classical model common in the literature at the level of the macroeconomy and at the level of the manufacturing sector. An attempt is made to improve upon the model by allowing the data to determine the dynamic structure of the model through an ARDL procedure. No significant impact of military spending is found in aggregate, but there is a significant negative impact for the manufacturing sector. This suggests that the cuts in domestic military procurement that have occurred since 1989 could lead to improved economic performance in South Africa through their impact on the manufacturing sector.

Pregnancy loss in lesbian and bisexual women: An online survey of experiences

Background: Although pregnancy loss is a distressing health event for many women, research typically equates women’s experiences of pregnancy loss to ‘married heterosexual women’s experiences of pregnancy loss’. The objective of this study was to explore lesbian and bisexual women’s experiences of miscarriage, stillbirth and neonatal death. Methods: This study analysed predominantly qualitative online survey data from 60 non-heterosexual, mostly lesbian, women from the UK, USA, Canada and Australia. All but one of the pregnancies was planned. Most respondents had physically experienced one early miscarriage during their first pregnancy, although a third had experienced multiple losses. Results: The analysis highlights three themes: processes and practices for conception; amplification of loss; and health care and heterosexism. Of the respondents, 84% conceived using donor sperm; most used various resources to plan conception and engaged in preconception health care. The experience of loss was amplified due to contextual factors and the investment respondents reported making in impending motherhood. Most felt that their loss(es) had made a ‘significant’/‘very significant’ impact on their lives. Many respondents experienced health care during their loss. Although the majority rated the overall standard of care as ‘good’/‘very good’/‘outstanding’, a minority reported experiencing heterosexism from health professionals. Conclusions: The implications for policy and practice are outlined. The main limitation was that the inflexibility of the methodology did not allow the specificities of women’s experiences to be probed further. It is suggested that both coupled and single non-heterosexual women should be made more visible in reproductive health and pregnancy loss research.

Theoretical evaluation of the cataract extraction-refraction-implantation techniques for intraocular lens power calculation

PURPOSE: To evaluate theoretically three previously published formulae that use intra-operative aphakic refractive error to calculate intraocular lens (IOL) power, not necessitating pre-operative biometry. The formulae are as follows: IOL power (D) = Aphakic refraction x 2.01 [Ianchulev et al., J. Cataract Refract. Surg.31 (2005) 1530]; IOL power (D) = Aphakic refraction x 1.75 [Mackool et al., J. Cataract Refract. Surg.32 (2006) 435]; IOL power (D) = 0.07x(2) + 1.27x + 1.22, where x = aphakic refraction [Leccisotti, Graefes Arch. Clin. Exp. Ophthalmol.246 (2008) 729]. METHODS: Gaussian first order calculations were used to determine the relationship between intra-operative aphakic refractive error and the IOL power required for emmetropia in a series of schematic eyes incorporating varying corneal powers, pre-operative crystalline lens powers, axial lengths and post-operative IOL positions. The three previously published formulae, based on empirical data, were then compared in terms of IOL power errors that arose in the same schematic eye variants. RESULTS: An inverse relationship exists between theoretical ratio and axial length. Corneal power and initial lens power have little effect on calculated ratios, whilst final IOL position has a significant impact. None of the three empirically derived formulae are universally accurate but each is able to predict IOL power precisely in certain theoretical scenarios. The formulae derived by Ianchulev et al. and Leccisotti are most accurate for posterior IOL positions, whereas the Mackool et al. formula is most reliable when the IOL is located more anteriorly. CONCLUSION: Final IOL position was found to be the chief determinant of IOL power errors. Although the A-constants of IOLs are known and may be accurate, a variety of factors can still influence the final IOL position and lead to undesirable refractive errors. Optimum results using these novel formulae would be achieved in myopic eyes.

Data analysis methods in optometry Part 7: multiple linear regression

Multiple regression analysis is a complex statistical method with many potential uses. It has also become one of the most abused of all statistical procedures since anyone with a data base and suitable software can carry it out. An investigator should always have a clear hypothesis in mind before carrying out such a procedure and knowledge of the limitations of each aspect of the analysis. In addition, multiple regression is probably best used in an exploratory context, identifying variables that might profitably be examined by more detailed studies. Where there are many variables potentially influencing Y, they are likely to be intercorrelated and to account for relatively small amounts of the variance. Any analysis in which R squared is less than 50% should be suspect as probably not indicating the presence of significant variables. A further problem relates to sample size. It is often stated that the number of subjects or patients must be at least 5-10 times the number of variables included in the study.5 This advice should be taken only as a rough guide but it does indicate that the variables included should be selected with great care as inclusion of an obviously unimportant variable may have a significant impact on the sample size required.

Prepaid monetary incentives on mail survey response

Increasing mail survey response using monetary incentives is a proven, but not always cost-effective, method in every population. This paper tackles the questions of whether it is worth using monetary incentives and the size of the inducement by testing a regression model of the impact of prepaid monetary incentives on response rates in consumer and organizational mail surveys. The results support their use and show that the inducement value makes a significant impact on the effect size. Importantly, no significant differences were found between consumer and organizational populations.

Characterisation of a harvesting step for monoclonal antibodies from mammalian cell culture

The focus of this research was defined by a poorly characterised filtration train employed to clarify culture broth containing monoclonal antibodies secreted by GS-NSO cells: the filtration train blinded unpredictably and the ability of the positively charged filters to adsorb DNA from process material was unknown. To direct the development of an assay to quantify the ability of depth filters to adsorb DNA, the molecular weight of DNA from a large-scale, fed-batch, mammalian cell culture vessel was evaluated as process material passed through the initial stages of the purification scheme. High molecular weight DNA was substantially cleared from the broth after passage through a disc stack centrifuge and the remaining low molecular weight DNA was largely unaffected by passage through a series of depth filters and a sterilising grade membrane. Removal of high molecular weight DNA was shown to be coupled with clarification of the process stream. The DNA from cell culture supernatant showed a pattern of internucleosomal cleavage of chromatin when fractionated by electrophoresis but the presence of both necrotic and apoptotic cells throughout the fermentation meant that the origin of the fragmented DNA could not be unequivocally determined. An intercalating fluorochrome, PicoGreen, was elected for development of a suitable DNA assay because of its ability to respond to low molecular weight DNA. It was assessed for its ability to determine the concentration of DNA in clarified mammalian cell culture broths containing pertinent monoclonal antibodies. Fluorescent signal suppression was ameliorated by sample dilution or by performing the assay above the pI of secreted IgG. The source of fluorescence in clarified culture broth was validated by incubation with RNase A and DNase I. At least 89.0 % of fluorescence was attributable to nucleic acid and pre-digestion with RNase A was shown to be a requirement for successful quantification of DNA in such samples. Application of the fluorescence based assay resulted in characterisation of the physical parameters governing adsorption of DNA by various positively charged depth filters and membranes in test solutions and the DNA adsorption profile of the manufacturing scale filtration train. Buffers that reduced or neutralised the depth filter or membrane charge, and those that impeded hydrophobic interactions were shown to affect their operational capacity, demonstrating that DNA was adsorbed by a combination of electrostatic and hydrophobic interactions. Production-scale centrifugation of harvest broth containing therapeutic protein resulted in the reduction of total DNA in the process stream from 79.8 μg m1-1 to 9.3 μg m1-1 whereas the concentration of DNA in the supernatant of pre-and post-filtration samples had only marginally reduced DNA content: from 6.3 to 6.0 μg m1-1 respectively. Hence the filtration train was shown to ineffective in DNA removal. Historically, blinding of the depth filters had been unpredictable with data such as numbers of viable cells, non-viable cells, product titre, or process shape (batch, fed-batch, or draw and fill) failing to inform on the durability of depth filters in the harvest step. To investigate this, key fouling contaminants were identified by challenging depth filters with the same mass of one of the following: viable healthy cells, cells that had died by the process of apoptosis, and cells that had died through the process of necrosis. The pressure increase across a Cuno Zeta Plus 10SP depth filter was 2.8 and 16.5 times more sensitive to debris from apoptotic and necrotic cells respectively, when compared to viable cells. The condition of DNA released into the culture broth was assessed. Necrotic cells released predominantly high molecular weight DNA in contrast to apoptotic cells which released chiefly low molecular weight DNA. The blinding of the filters was found to be largely unaffected by variations in the particle size distribution of material in, and viscosity of, solutions with which they were challenged. The exceptional response of the depth filters to necrotic cells may suggest the cause of previously noted unpredictable filter blinding whereby a number of necrotic cells have a more significant impact on the life of a depth filter than a similar number of viable or apoptotic cells. In a final set of experiments the pressure drop caused by non-viable necrotic culture broths which had been treated with DNase I or benzonase was found to be smaller when compared to untreated broths: the abilities of the enzyme treated cultures to foul the depth filter were reduced by 70.4% and 75.4% respectively indicating the importance of DNA in the blinding of the depth filter studied.

Knowledge acquisition in international strategic alliances among Malaysian manufacturing firms

This thesis examines the process of knowledge acquisition by Malaysian manufacturing firms through their involvement in international strategic alliances. The strategic alliances can be with or without equity involvement. Firms involved with a foreign partner with equity involvement are joint venture firms while non-equity involvement are firms that engaged in contractual agreements. Using empirical evidence from 65 international alliances gathered through a survey conducted in high-technology manufacturing sectors, several factors that influence the process of knowledge acquisition are examined. The factors are: learning capacity, experience, goals, active involvement and accessibility to the foreign knowledge. Censored regression analysis and ordered probit analysis are used to analyse the effects of these factors on knowledge acquisition and its determinant parts, and the effects of knowledge acquisition and its determinants on the performance of the alliances. A second questionnaire gathered evidence relating to the factors, which encouraged tacit knowledge transfer between the foreign and Malaysian partners in international alliances. The key findings of the study are: knowledge acquisition in international strategic alliances is influenced by five determining factors; learning capacity, experience, articulated goals, active involvement and accessibility; new technology knowledge, product development knowledge and manufacturing process knowledge are influenced differently by the determining factors; knowledge acquisition and its determinant factors have a significant impact on the firm’s performance; cultural differences tend to moderate the effect on the firm’s performance; acquiring tacit knowledge is not only influenced by the five determinant factors but also by other factors, such as dependency, accessibility, trust, manufacturing control, learning methods and organisational systems; Malaysian firms involved in joint ventures tend to acquire more knowledge than those involved in contractual agreements, but joint ventures also exhibit higher degrees of dependency than contractual agreements; and the presence of R&D activity in the Malaysian partner encourages knowledge acquisition, but the amount of R&D expenditure has no effect on knowledge acquisition.

Third sector organisations and social welfare : a study of the role of social service and charitable organisations in Taiwan

This study is about the role and operation of ‘third sector’ organisations (TSOs) within the Taiwanese social welfare context. TSOs have increased dramatically and become actively involved in social service provision. This phenomenon has not only had significant impact on the development and operation of TSOs in Taiwan but it is also of increasing interest to public policy academics. The latter are especially interested in the implications for the government-third sector relationship. This research examines the reasons why TSOs have been established, why they actively participate in social service provision, and their role and operation within the social welfare context of Taiwan. The study has both quantitative and qualitative data. It sampled ‘social service’ and ‘charitable’ organisations (SSCOs), which are the main type of TSOs in Taiwan, to examine their role, operation and interaction with government. Questionnaires were mailed to collect quantitative data first. After the quantitative data were collected and analysed, semi-structured interviews were undertaken to collect qualitative data. The study found that TSOs in Taiwan exist in a highly institutionalised environment, which is affected by traditional Confucian ideas and contemporary Western ideas such as social justice and civil rights. The rapid growth of TSOs has a strong connection with the desire to fill social service gaps left by government and family. TSOs mainly play the role of service provider rather than that of advocate. They cooperate with government in social service provision and have developed different types of symbiotic relationships with government. A ‘resonance effect’ between government and TSOs was also found as they implement social policy.

Promoting the German navy in the British Empire:the Central League for German Navy Clubs Abroad 1898-1918

German unification in 1871 not only changed the political, economic and geographical landscape of the country, it also had a significant impact on those Germans who found themselves living outside, or migrating across, the borders of the newly founded Empire. It also focuses on the activities of the Central League in Britain and its Empire. For comparative reasons, some areas outside the Empire also included. Within Britain, five local branches can be identified during the period 1898 to 1914: London, Birmingham, Newcastle, Glasgow, and Edinburgh-Leith. For London, membership numbers obtained, but judging by annual contributions this branch appears strongest in Britain. The article has shown that researching the activities of the Central League in Britain and its Empire can add valuable insights to the mechanics of transnational ethnic network creation, as well as to the nature of potentially frictional contact zones between German migrants and British colonial rule.

Cholinesterase inhibitors for dementia with Lewy bodies, Parkinson's disease dementia and cognitive impairment in Parkinson's disease

Background - Previous Cochrane reviews have considered the use of cholinesterase inhibitors in both Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB). The clinical features of DLB and PDD have much in common and are distinguished primarily on the basis of whether or not parkinsonism precedes dementia by more than a year. Patients with both conditions have particularly severe deficits in cortical levels of the neurotransmitter acetylcholine. Therefore, blocking its breakdown using cholinesterase inhibitors may lead to clinical improvement. Objectives - To assess the efficacy, safety and tolerability of cholinesterase inhibitors in dementia with Lewy bodies (DLB), Parkinson’s disease with dementia (PDD), and cognitive impairment in Parkinson’s disease falling short of dementia (CIND-PD) (considered as separate phenomena and also grouped together as Lewy body disease). Search methods - The trials were identified from a search of ALOIS, the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group (on 30 August 2011) using the search terms Lewy, Parkinson, PDD, DLB, LBD. This register consists of records from major healthcare databases (MEDLINE, EMBASE, PsycINFO, CINAHL) and many ongoing trial databases and is updated regularly. Reference lists of relevant studies were searched for additional trials. Selection criteria - Randomised, double-blind, placebo-controlled trials assessing the efficacy of treatment with cholinesterase inhibitors in DLB, PDD and cognitive impairment in Parkinson’s disease (CIND-PD). Data collection and analysis - Data were extracted from published reports by one review author (MR). The data for each 'condition' (that is DLB, PDD or CIND-PD) were considered separately and, where possible, also pooled together. Statistical analysis was conducted using Review Manager version 5.0. Main results - Six trials met the inclusion criteria for this review, in which a total of 1236 participants were randomised. Four of the trials were of a parallel group design and two cross-over trials were included. Four of the trials included participants with a diagnosis of Parkinson's disease with dementia (Aarsland 2002a; Dubois 2007; Emre 2004; Ravina 2005), of which Dubois 2007 remains unpublished. Leroi 2004 included patients with cognitive impairment and Parkinson's disease (both with and without dementia). Patients with dementia with Lewy bodies (DLB) were included in only one of the trials (McKeith 2000). For global assessment, three trials comparing cholinesterase inhibitor treatment to placebo in PDD (Aarsland 2002a; Emre 2004; Ravina 2005) reported a difference in the Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC) score of -0.38, favouring the cholinesterase inhibitors (95% CI -0.56 to -0.24, P < 0.0001). For cognitive function, a pooled estimate of the effect of cholinesterase inhibitors on cognitive function measures was consistent with the presence of a therapeutic benefit (standardised mean difference (SMD) -0.34, 95% CI -0.46 to -0.23, P < 0.00001). There was evidence of a positive effect of cholinesterase inhibitors on the Mini-Mental State Examination (MMSE) in patients with PDD (WMD 1.09, 95% CI 0.45 to 1.73, P = 0.0008) and in the single PDD and CIND-PD trial (WMD 1.05, 95% CI 0.42 to 1.68, P = 0.01) but not in the single DLB trial. For behavioural disturbance, analysis of the pooled continuous data relating to behavioural disturbance rating scales favoured treatment with cholinesterase inhibitors (SMD -0.20, 95% CI -0.36 to -0.04, P = 0.01). For activities of daily living, combined data for the ADCS and the Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living rating scales favoured treatment with cholinesterase inhibitors (SMD -0.20, 95% CI -0.38 to -0.02, P = 0.03). For safety and tolerability, those taking a cholinesterase inhibitor were more likely to experience an adverse event (318/452 versus 668/842; odds ratio (OR) 1.64, 95% CI 1.26 to 2.15, P = 0.0003) and to drop out (128/465 versus 45/279; OR 1.94, 95% CI 1.33 to 2.84, P = 0.0006). Adverse events were more common amongst those taking rivastigmine (357/421 versus 173/240; OR 2.28, 95% CI 1.53 to 3.38, P < 0.0001) but not those taking donepezil (311/421 versus 145/212; OR 1.24, 95% CI 0.86 to 1.80, P = 0.25). Parkinsonian symptoms in particular tremor (64/739 versus 12/352; OR 2.71, 95% CI 1.44 to 5.09, P = 0.002), but not falls (P = 0.39), were reported more commonly in the treatment group but this did not have a significant impact on the UPDRS (total and motor) scores (P = 0.71). Fewer deaths occurred in the treatment group than in the placebo group (4/465 versus 9/279; OR 0.28, 95% CI 0.09 to 0.84, P = 0.03). Authors' conclusions - The currently available evidence supports the use of cholinesterase inhibitors in patients with PDD, with a positive impact on global assessment, cognitive function, behavioural disturbance and activities of daily living rating scales. The effect in DLB remains unclear. There is no current disaggregated evidence to support their use in CIND-PD.