887 resultados para Difference-in-differences


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Many organisations are encouraging their staff to integrate work and non-work, but a qualitative study of young professionals found that many crave greater segregation rather than more integration. Most wished to build boundaries to separate the two and simplify a complex world. Where working practices render traditional boundaries of time and space ineffective, this population seems to create new idiosyncratic boundaries to segregate work from non-work. These idiosyncratic boundaries depended on age, culture and life-stage though for most of this population there was no appreciable gender difference in attitudes to segregating work and non-work. Gender differences only became noticeable for parents. A matrix defining the dimensions to these boundaries is proposed that may advance understanding of how individuals separate their work and personal lives. In turn, this may facilitate the development of policies and practices to integrate work and non-work that meet individual as well as organisational needs.

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The dramatic GDP and export growth of Ireland over the last decade forms a marked contrast with that of its nearest neighbour Northern Ireland. In Ireland, export volume growth averaged 15.5% p.a. from 1991 to 1999 compared with 6.3% from Northern Ireland. Using data on individual manufacturing plants this paper considers the determinants of export performance in the two areas. Larger, externally owned plants with higher skill levels are found to have the highest export propensities in both areas. Other influences (plant age, R&D, etc.) prove more strongly conditional on location, plant size, and ownership. Structural factors (e.g. ownership, industry) explain almost all of the difference in export propensity between larger plants in Northern Ireland and Ireland but only around one-third of that between smaller plants. Significant differences are also evident between plants in terms of their sources of new technology. For indigenously owned plants, inhouse R&D is important. For externally owned plants, R&D conducted elsewhere in the group - typically outside Ireland and Northern Ireland - proves more significant. This external dependency and lower than expected export propensity on the part of small plants in Northern Ireland represent significant policy challenges for the future.© 2006 Scottish Economic Society. Published by Blackwell Publishing Ltd.

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This paper reports results from an ongoing project examining what managers think about knowledge management in the context of their organisation. This was done in a facilitated computerassisted group workshop environment. Here we compare the outcomes of workshops held for two relatively large UK organisations, one public sector and the other private. Our conclusions are that there are relatively few differences between the perceptions of these two groups of managers, and that these differences stem more from the stage of the knowledge management life cycle that the two organisations have reached, rather than from the difference in context between public and private sector. © iKMS & World Scientific Publishing Co.

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Background The introduction of women officers into HM Prison Service raised questions regarding women's ability to perform what had traditionally been a male role. Existing research is inconclusive as to whether female prison officers are as competent as male prison officers, and whether there are gender differences in job performance. This study examined prisoners' perceptions of male and female prison officers' performance. Hypotheses The hypotheses were that overall competence and professionalism ratings would not differ for men and women officers, but that there would be differences in how men and women were perceived to perform their roles. Women were expected to be rated as more communicative, more empathic and less disciplining. Method The Prison Officer Competency Rating Scale (PORS) was designed for this study. Ratings on the PORS for male and female officers were given by 57 adult male prisoners. Results There was no significant difference in prisoners' ratings of overall competence of men and women officers. Of the PORS subscales, there were no gender differences in Discipline and Control, Communication or Empathy, but there was a significant difference in Professionalism, where prisoners rated women as more professional. Conclusion The failure to find any differences between men and women in overall job competence, or on communication, empathy and discipline, as perceived by prisoners, suggests that men and women may be performing their jobs similarly in many respects. Women were rated as more professional, and items contributing to this scale related to respecting privacy and keeping calm in difficult situations, where there may be inherent gender biases. Copyright © 2005 Whurr Publishers Ltd.

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This chapter illustrates extratextual and intratextual aspects of ideology as related to translation with a case study, a policy document by Tony Blair and Gerhard Schröder, jointly published in English and German in June 1999. Textual features of the two language versions are compared and linked to the social contexts. Concepts and methods of critical discourse analysis and of descriptive and functionalist approaches to translation are applied for this purpose. In particular, reactions to the German text in Germany are explained with reference to the socio-political and ideological conditions of the text production, which was a case of parallel text production combined with translation. It is illustrated that decisions at the linguistic micro-level have had effects for a political party, reflected for example in the German Social Democratic Party debating its identity due to the textual treatment of ideological keywords. The subtle differences revealed in a comparative analysis of the two texts indicate the text producers' awareness of ideological phenomena in the respective cultures. Both texts thus serve as windows onto ideologies and political power relations in the contemporary world.

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Purpose. The prevalence of myopia is known to vary with age, ethnicity, level of education, and socioeconomic status, with a high prevalence reported in university students and in people from East Asian countries. This study determines the prevalence of ametropia in a mixed ethnicity U.K. university student population and compares associated ocular biometric measures. Methods. Refractive error and related ocular component data were collected on 373 first-year U.K. undergraduate students (mean age = 19.55 years ± 2.99, range = 17-30 years) at the start of the academic year at Aston University, Birmingham, and the University of Bradford, West Yorkshire. The ethnic variation of the students was as follows: white 38.9%, British Asian 58.2%, Chinese 2.1%, and black 0.8%. Noncycloplegic refractive error was measured with an infrared open-field autorefractor, the Shin-Nippon NVision-K 5001 (Shin Nippon, Ryusyo Industrial Co. Ltd, Osaka, Japan). Myopia was defined as a mean spherical equivalent (MSE) less than or equal to -0.50 D. Hyperopia was defined as an MSE greater than or equal to +0.50 D. Axial length, corneal curvature, and anterior chamber depth were measured using the Zeiss IOLMaster (Carl Zeiss, Jena, GmBH). Results. The analysis was carried out only for white and British Asian groups. The overall distribution of refractive error exhibited leptokurtosis, and prevalence levels were similar for white and British Asian (the predominant ethnic group) students across each ametropic group: myopia (50% vs. 53.4%), hyperopia (18.8% vs. 17.3%), and emmetropia (31.2% vs. 29.3%). There were no significant differences in the distribution of ametropia and biometric components between white and British Asian samples. Conclusion. The absence of a significant difference in refractive error and ocular components between white and British Asian students exposed to the same educational system is of interest. However, it is clear that a further study incorporating formal epidemiologic methods of analysis is required to address adequately the recent proposal that juvenile myopia develops principally from myopiagenic environments and is relatively independent of ethnicity.

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Parmelia conspersa (Ehrh. Ex Ach.)Ach. is a foliose lichen found more frequently on south facing compared with north facing rock surfaces in South Gwynedd, Wales, UK. The radial growth of thalli of P. conspersa from a north and a south facing rock surface was measured in situ at intervals of two months for 1 yr during 1990/1991. Mean annual radial growth rates were greater on the south compared with the north facing rock surface. In addition, the pattern of radial growth varied during the year with maximum growth recorded in the Feb/Mar. period especially on the south facing rock surface. The levels of ribitol, arabitol and mannitol were measured in individual lobes of P. conspersa collected from the same rock surfaces on 4 days (2 Jun; 7 July and 30 Nov. 1990 and 29 Mar. 1991) during 1990/1991. The total of the three carbohydrates varied between days; the levels of arbitol and ribitol being significantly lower in the 7 July sample on both north and south facing rock surfaces. In addition, the levels ribitol, arabitol and mannitol were higher on the south facing rock surface especially in the summer samples. The ratio of arabitol plus mannitol to ribitol and the mannitol/arabitol ratio varied more between days sampled than between north and south facing rock surfaces. The level of ribitol in individual thalli was positively correlated with arabitol on the north facing and with mannitol on the south facing slope. These results suggest that differences in the radial growth of P. conspersa thalli with aspect are more likely to reflect higher rates of photosynthesis on the south facing rock surface rather than large difference in the way carbohydrates were partitioned on the different surfaces. Lower radial growth rates may place P. conspersa at a competitive disadvantage on north facing rock surfaces.

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Investigations into the modelling techniques that depict the transport of discrete phases (gas bubbles or solid particles) and model biochemical reactions in a bubble column reactor are discussed here. The mixture model was used to calculate gas-liquid, solid-liquid and gasliquid-solid interactions. Multiphase flow is a difficult phenomenon to capture, particularly in bubble columns where the major driving force is caused by the injection of gas bubbles. The gas bubbles cause a large density difference to occur that results in transient multi-dimensional fluid motion. Standard design procedures do not account for the transient motion, due to the simplifying assumptions of steady plug flow. Computational fluid dynamics (CFD) can assist in expanding the understanding of complex flows in bubble columns by characterising the flow phenomena for many geometrical configurations. Therefore, CFD has a role in the education of chemical and biochemical engineers, providing the examples of flow phenomena that many engineers may not experience, even through experimentation. The performance of the mixture model was investigated for three domains (plane, rectangular and cylindrical) and three flow models (laminar, k-e turbulence and the Reynolds stresses). mThis investigation raised many questions about how gas-liquid interactions are captured numerically. To answer some of these questions the analogy between thermal convection in a cavity and gas-liquid flow in bubble columns was invoked. This involved modelling the buoyant motion of air in a narrow cavity for a number of turbulence schemes. The difference in density was caused by a temperature gradient that acted across the width of the cavity. Multiple vortices were obtained when the Reynolds stresses were utilised with the addition of a basic flow profile after each time step. To implement the three-phase models an alternative mixture model was developed and compared against a commercially available mixture model for three turbulence schemes. The scheme where just the Reynolds stresses model was employed, predicted the transient motion of the fluids quite well for both mixture models. Solid-liquid and then alternative formulations of gas-liquid-solid model were compared against one another. The alternative form of the mixture model was found to perform particularly well for both gas and solid phase transport when calculating two and three-phase flow. The improvement in the solutions obtained was a result of the inclusion of the Reynolds stresses model and differences in the mixture models employed. The differences between the alternative mixture models were found in the volume fraction equation (flux and deviatoric stress tensor terms) and the viscosity formulation for the mixture phase.

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Deformation microstructures in two batches of commercially pure copper (A and B) of allnost similar composition have been studied after rolling reductions from 5% to 95%. X- ray diffraction, optical metallography, scanning electron microscopy in the back-scattered mode, transmission and scanning electron microscopy have been used to examine the deformation microstructure. At low strains (~10 %) the deformation is accommodated by uniform octahedral slip. Microbands that occur as sheet like features usually on the {111} slip planes are formed after 10% reduction. The misorientations between rnicrobonds ond the matrix are usually small (1 - 2° ) and the dislocations within the bands suggest that a single slip system has been operative. The number of microbands increases with strain, they start to cluster and rotate after 60% reduction and, after 90 %, they become almost perfectly aligned with the rolling direction. There were no detectable differences in deformation microstructure between the two materials up to a deformation level of 60% but subsequently, copper B started to develop shear bands which became very profuse by 90% reduction. By contrast, copper A at this stage of deformation developed a smooth laminated structure. This difference in the deformation microstructures has been attributed to traces of unknown impurity in D which inhibit recovery of work hardening. The preferred orientations of both were typical of deformed copper although the presence of shear bands was associated wth a slightly weaker texture. The effects of rolling temperature and grain size on deformation microstructure were also investigated. It was concluded that lowering the rolling temperature or increasing the initial grain size encourages the material to develop shear bands after heavy deformation. Recovery and recrystallization have been studied in both materials during annealing. During recrystallization the growth of new grains showed quite different characteristics in the two cases. Where shear bands were present these acted as nucleation sites and produced a wide spread of recrystallized grain orientations. The resulting annealing textures were very weak. In the absence of shear bands, nucleation occurs by a remarkably long range bulging process which creates the cube orientation and an intensely sharp annealing texture. Cube oriented regions occur in long bands of highly elongated and well recovered cells which contain long range cumulative micorientations. They are transition bands with structural characteristics ideally suited for nucleation of recrystallization. Shear banding inhibits the cube texture both by creating alternative nuclei and by destroying the microstructural features necessary for cube nucleation.

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The aim of this research project is to compare published history textbooks written for upper-secondary/tertiary study in the U.S. and Spain using Halliday's (1994) Theme/Rheme construct. The motivation for using the Theme/Rheme construct to analyze professional texts in the two languages is two-fold. First of all, while there exists a multitude of studies at the grammatical and phonological levels between the two languages, very little analysis has been carried out in comparison at the level of text, beyond that of comparing L1/L2 student writing. Secondly, thematic considerations allow the analyst to highlight areas of textual organization in a systematic way for purposes of comparison. The basic hypothesis tested here rests on the premise that similarity in the social function of the texts results in similar Theme choice and thematic patterning across languages, barring certain linguistic constraints. The corpus for this study consists of 20 texts: 10 from various history textbooks published in the U.S. and 10 from various history textbooks published in Spain. The texts chosen represent a variety of authors, in order to control for author style or preference. Three overall areas of analysis were carried out, representing Halliday's (1994) three metafunctions: the ideational, the interpersonal and the textual. The ideational analysis shows similarities across the two corpora in terms of participant roles and circumstances as Theme, with a slight difference in participants involved in material processes, which is shown to reflect a minor difference in the construal of the field of history in the two cultures. The textual analysis shows overall similarities with respect to text organization, and the interpersonal analysis shows overall similarities as regards the downplay of discrepant interpretations of historical events as well as a low frequency of interactive textual features, manifesting the informational focus of the texts. At the same time, differences in results amongst texts within each of the corpora demonstrate possible effect of subject matter, in many cases, and individual author style in others. Overall, the results confirm that similarity in content, but above all in purpose and audience, result in texts which show similarities in textual features, setting aside certain grammatical constraints.

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PURPOSE. To establish an alternative method, sequential and diameter response analysis (SDRA), to determine dynamic retinal vessel responses and their time course in serial stimulation compared with the established method of averaged diameter responses and standard static assessment. METHODS. SDRA focuses on individual time and diameter responses, taking into account the fluctuation in baseline diameter, providing improved insight into reaction patterns when compared with established methods as delivered by retinal vessel analyzer (RVA) software. SDRA patterns were developed with measurements from 78 healthy nonsmokers and subsequently validated in a group of 21 otherwise healthy smokers. Fundus photography and retinal vessel responses were assessed by RVA, intraocular pressure by contact tonometry, and blood pressure by sphygmomanometry. RESULTS. Compared with the RVA software method, SDRA demonstrated a marked difference in retinal vessel responses to flickering light (P 0.05). As a validation of that finding, SDRA showed a strong relation between baseline retinal vessel diameter and subsequent dilatory response in both healthy subjects and smokers (P 0.001). The RVA software was unable to detect this difference or to find a difference in retinal vessel arteriovenous ratio between smokers and nonsmokers (P 0.243). However, SDRA revealed that smokers’ vessels showed both an increased level of arterial baseline diameter fluctuation before flicker stimulation (P 0.005) and an increased stiffness of retinal arterioles (P 0.035) compared with those in nonsmokers. These differences were unrelated to intraocular pressure or systemic blood pressure. CONCLUSIONS. SDRA shows promise as a tool for the assessment of vessel physiology. Further studies are needed to explore its application in patients with vascular diseases.

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Poster section Design. Retrospective study. Purpose. To assess whether there are changes in foveal thickness (FT) and total macular volume (TMV) in pregnancy in diabetic subjects. Methods. The audit consisted of pregnant women with diabetes, with no maculopathy, who completed their antenatal care at Birmingham Heartlands Hospital. The Zeiss Stratus Optical coherence tomography (OCT) was performed on patients attending diabetic retinopathy (DR) screening at intervals throughout their pregnancy. To be included in the audit patients had to have at least one OCT scan during their pregnancy. Results. Altogether there were 8 type 1 and 22 type 2 patients with mean diabetes duration of 6 years (range 1-20). Mean gestation at DR screening with OCT during the first trimester was 9.7 weeks (6-13) (n=22). The mean and standard deviation for FT for the right was 179.1 µm ± 21.49 and for the left eye was 187.3 µm ± 23.55. The mean TMV was right 6.43 µm ± 0.35 and left 6.50 µm ± 0.39. The mean gestation at DR screening with OCT during the second trimester was 23.4 weeks (18-26) (n=25). The mean FT for the right was 191.4 µm ± 22.70 and the left 195.6 µm ± 24.77. The mean TMV was right 6.74 µm ± 0.45 and left 6.91 µm ± 0.35. The gestation of DR screening with OCT during the third trimester was 31.1 weeks (27-36) (n=15). The mean FT for the right was 181.5 µm ± 24.84 and for the left 193.1 µm ± 28.55. The mean TMV was right 6.80 µm ± 0.40 and left 6.84 µm ± 0.31. There were no significant differences in FT over the 3 trimesters. The TMV showed a significant difference when comparing the first and second trimesters (p<0.05). However, there was no significant statistical difference in TMV in the second and third trimesters. None of the patients showed any macula edema on the OCT. Conclusions. The results suggest there is no significant change in foveal thickness in pregnancy in diabetic subjects. There was a significant statistical difference in total macular volume in the second trimester; however, this would not be clinically significant. This is an important observation proven by the OCT which has not been previously studied.

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The size frequency distributions of diffuse, primitive and classic beta/A4 deposits was studied in single sections in the hippocampus, parahippocampal gyrus (PHG) and lateral occipitotemporal gyrus (LOT) in five cases of Alzheimer's disease. In most brain regions, the size distribution of the diffuse deposits was significantly different from that of the primitive and classic deposits. The data suggested that larger diffuse deposits appeared to be converted less often into primitive and classic deposits. Significant differences in the size distribution of primitive deposits were commonly observed between brain regions in which there was no difference in the size distribution of the diffuse deposits. Hence, local brain factors may influence the size of diffuse deposit which can be converted into mature amyloid deposit.

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If, as is widely believed, schizophrenia is characterized by abnormalities of brain functional connectivity, then it seems reasonable to expect that different subtypes of schizophrenia could be discriminated in the same way. However, evidence for differences in functional connectivity between the subtypes of schizophrenia is largely lacking and, where it exists, it could be accounted for by clinical differences between the patients (e.g. medication) or by the limitations of the measures used. In this study, we measured EEG functional connectivity in unmedicated male patients diagnosed with either positive or negative syndrome schizophrenia and compared them with age and sex matched healthy controls. Using new methodology (Medkour et al., 2009) based on partial coherence, brain connectivity plots were constructed for positive and negative syndrome patients and controls. Reliable differences in the pattern of functional connectivity were found with both syndromes showing not only an absence of some of the connections that were seen in controls but also the presence of connections that the controls did not show. Comparing connectivity graphs using the Hamming distance, the negative-syndrome patients were found to be more distant from the controls than were the positive syndrome patients. Bootstrap distributions of these distances were created which showed a significant difference in the mean distances that was consistent with the observation that negative-syndrome diagnosis is associated with a more severe form of schizophrenia. We conclude that schizophrenia is characterized by widespread changes in functional connectivity with negative syndrome patients showing a more extreme pattern of abnormality than positive syndrome patients.

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Few researchers have examined the nature and determinants of earnings differentials among religious groups, and none has been undertaken in the context of conflict-prone multi-religious societies like the one in India. We address this lacuna in the literature by examining the differences in the average log earnings of Hindu and Muslim wage earners in India, during the 1987–2005 period. Our results indicate that education differences between Hindu and Muslim wage earners, especially differences in the proportion of wage earners with tertiary education, are largely responsible for the differences in the average log earnings of the two religious groups across the years. By contrast, differences in the returns to education do not explain the aforementioned difference in average log earnings. In conclusion, we discuss some policy implications.