A Tentative Modeling Study of the Effect of Wall Reactions on Oxidation Phenomena

This paper gives details of a tentative modeling study that investigates the inhibiting effect of internal reactor walls treated with acid..

Low serum vitamin D is associated with axial length and risk of myopia in young children

The aim of the study was to investigate the relationship between serum 25(OH)D levels and axial length (AL) and myopia in 6-year-old children. A total of 2666 children aged 6 years participating in the birth-cohort study Generation R underwent a stepwise eye examination. First, presenting visual acuity (VA) and AL were performed. Second, automated cycloplegic refraction was measured if LogMAR VA > 0.1. Serum 25-hydroxyvitamin D [25(OH)D] was determined from blood using liquid chromatography/tandem mass spectrometry. Vitamin D related SNPs were determined with a SNP array; outdoor exposure was assessed by questionnaire. The relationships between 25(OH)D and AL or myopia were investigated using linear and logistic regression analysis. Average 25(OH)D concentration was 68.8 nmol/L (SD ± 27.5; range 4–211); average AL 22.35 mm (SD ± 0.7; range 19.2–25.3); and prevalence of myopia 2.3 % (n = 62). After adjustment for covariates, 25(OH)D concentration (per 25 nmol/L) was inversely associated with AL (β −0.043; P < 0.01), and after additional adjusting for time spent outdoors (β −0.038; P < 0.01). Associations were not different between European and non-European children (β −0.037 and β −0.039 respectively). Risk of myopia (per 25 nmol/L) was OR 0.65 (95 % CI 0.46–0.92). None of the 25(OH)D related SNPs showed an association with AL or myopia. Lower 25(OH)D concentration in serum was associated with longer AL and a higher risk of myopia in these young children. This effect appeared independent of outdoor exposure and may suggest a more direct role for 25(OH)D in myopia pathogenesis

Development of refractive errors - what can we learn from inherited retinal dystrophies?

PURPOSE: It is unknown which retinal cells are involved in the retina-to-sclera signaling cascade causing myopia. As inherited retinal dystrophies (IRD) are characterized by dysfunction of a single retinal cell type and have a high risk of refractive errors, a study investigating the affected cell type, causal gene and refractive error in IRDs may provide insight herein. DESIGN: Case-control study. METHODS: _Study population:_ 302 patients with IRD from two ophthalmogenetic centers in the Netherlands. _Reference population:_ population-based Rotterdam Study-III and ERF Study (N=5,550). Distributions and mean spherical equivalent (SE) were calculated for main affected cell type and causal gene; and risks of myopia and hyperopia were evaluated using logistic regression. RESULTS: Bipolar cell related dystrophies were associated with the highest risk of SE high myopia 239.7; OR mild hyperopia 263.2, both P<0.0001; SE -6.86 D [SD 6.38]); followed by cone dominated dystrophies (OR high myopia 19.5, P<0.0001; OR high hyperopia 10.7, P=0.033; SE -3.10 D [SD 4.49]); rod dominated dystrophies (OR high myopia 10.1, P<0.0001; OR high hyperopia 9.7, P=0.001; SE -2.27 D [SD 4.65]); and RPE related dystrophies (OR low myopia 2.7; P=0.001; OR high hyperopia 5.8; P=0.025; SE -0.10 D [SD 3.09]). Mutations in RPGR (SE -7.63 D [SD 3.31]) and CACNA1F (SE -5.33 D [SD 3.10]) coincided with the highest degree of myopia; in CABP4 (SE 4.81 D [SD 0.35]) with the highest degree of hyperopia. CONCLUSIONS: Refractive errors, in particular myopia, are common in IRD. The bipolar synapse, and the inner and outer segments of the photoreceptor may serve as critical sites for myopia development

When do myopia genes have their effect? Comparison of genetic risks between children and adults

Previous studies have identified many genetic loci for refractive error and myopia. We aimed to investigate the effect of these loci on ocular biometry as a function of age in children, adolescents, and adults. The study population consisted of three age groups identified from the international CREAM consortium: 5,490 individuals aged 25 years. All participants had undergone standard ophthalmic examination including measurements of axial length (AL) and corneal radius (CR). We examined the lead SNP at all 39 currently known genetic loci for refractive error identified from genome-wide association studies (GWAS), as well as a combined genetic risk score (GRS). The beta coefficient for association between SNP genotype or GRS versus AL/CR was compared across the three age groups, adjusting for age, sex, and principal components. Analyses were Bonferroni-corrected. In the age group <10 years, three loci (GJD2, CHRNG, ZIC2) were associated with AL/CR. In the age group 10–25 years, four loci (BMP2, KCNQ5, A2BP1, CACNA1D) were associated; and in adults 20 loci were associated. Association with GRS increased with age; β = 0.0016 per risk allele (P = 2 × 10–8) in <10 years, 0.0033 (P = 5 × 10–15) in 10- to 25-year-olds, and 0.0048 (P = 1 × 10–72) in adults. Genes with strongest effects (LAMA2, GJD2) had an early effect that increased with age. Our results provide insights on the age span during which myopia genes exert their effect. These insights form the basis for understanding the mechanisms underlying high and pathological myopia

Management, structuur en cultuur : over het gebruik van organisatietheorieën in Breda

This book deals with organizational change in two different ways. One way is the historical description of several attempts to implement organizational change in one particular organization. That organization is the local civil service of Breda, a city in the southern part of the Netherlands with a history that goes back to the thirteenth century. This book covers the period of about thirty years from 1965 until 1996. In this period Breda had between 120.000 and 130.000 inhabitants and the civil service varied between 1200 and 1800 employees. The historical description focuses not only on the changes as such but also on the situation that existed when the attempts to change were undertaken (the environmental conditions). Main goal in this part of the study is to create a basis for an answer to the question: What factors or conditions were decisive for the claimed success of the changes that took place in 1992, where similar attempts at earlier dates seemed to have failed?The other way to treat organizational change in this study is induced by the question: Which organization theory or theories were used in the reorganizations described in the historical part? In order to obtain an answer to this question it was necessary to go into the character of organizations theory - which is thought to be a body of knowledge - and into the relevancy of organizations theory for practical use - which is thought to be small. A theoretical model for research is proposed in part 2. This model is based upon three major assumptions.guidelines and directions derived from organizations theory are insufficient to support organizational change in practice. This causes "changers" (those who initiate the desired change) to develop their own, "private" organization theory. An important part of this study is concerned with the reconstruction of those private theories.the private theories of changers are expressed one way or another in the documents used to realise the desired organizational change. In the addendum to this study quotes from the documents used are translated into "central concepts" of the changers. These central concepts are considered to be the framework of the private organization theories.organizational change is realised on one or more of three organizational dimensions: management, structure and culture. These dimensions are influenced strongly by environmental factors. Technologic possibilities available, the actual economic situation, prevailing social values and political and governmental conditions are considered to be the most important environmental conditions.The last section of part 2 (chapter 6) gives a short analysis of the specific character of Dutch local government and public service. In the local civil service the position of the town clerk in most cities has evolved to that of city manager in the period considered.The historical account in part 3 is subdivided into 5 chapters, the first being a short and global sketch of the history of the Netherlands since World War II in order to give a general background for the developments in Breda. Each of the other four give a description of one of the successive attempts to reorganize the civil service of Breda. In these chapters attention is also given to several problems of local policy that filled, for the most part, the political agenda.In part 4, the model developed in part 2 is applied on documents used to realise the desired changes described in part 3. The private theories for each period are reconstructed and compared to the general organization theory existing at the time. An important aspect of this analysis is that private and general organization theory and the desired and realised organization are described in terms of the three dimensions (management, structure and culture) of the proposed referential model in part 2. Each chapter of part 4 closes with a summary of conclusions with respect to that period.General conclusions derived from the whole study and a few suggestions for further research are gathered in part 5. The most important conclusions can be presented in the following statements.Writers on organizations agree to a large extent on the fact that environmental conditions have a bearing on the structure and functioning of organizations. Many of them even agree on the fact that organizations theories are influenced by the economic and social forces of their time. Nevertheless proposed organization theories hardly ever try to specify the situation in which they are developed.An explanation for this lack of attention may be found in the emphasis on comparative analysis of organizational research. In comparing organizations in a specific historical period, technological economic, social and political conditions can be viewed as the same for all organizations at the time. In that case those environmental conditions have no bearing on the results of the research and need not be made explicit.Organizational change can be considered as change on the three dimensions: management, structure and culture. In the case observed in this study the same set of rather simple rules was used for creating change in each of the four successive periods on the dimensions management: (replace sitting managers) and structure (enhance line-staff relations, put together what belongs together; though criteria to do this differ from period to period; and decrease span of control).The most important motive to introduce large scale changes in the case observed, therefore, seems to be the need to change organizational culture. In the case considered, the organization started with a power oriented culture. The first attempt on change tried to implement a role oriented culture but failed for the most part as a result of the existing power structure.The second attempt was accompanied by the wave of democratization of the late sixties and early seventies which undermined the power structure in the organization. The rather low pressure on reinforcing role relations, except for those belonging to project management, caused a major shift towards a task culture in which hardly anybody seemed to have authority. In this situation project management played a major role.In the third attempt, under pressure of the economic recession, legitimate authority, the political power of mayor and aldermen, reinforced a strong role culture. As a result of this change the existing structural elements of project management were practically eliminated. The position of the chief executive level (the town clerk) was weak.In the fourth attempt power shifted from the political to the chief executive level. This shift was enabled by the weak political position of mayor and aldermen and the authority bestowed on the town clerk.</p

“There is so much more for us to lose if we were to kill ourselves”: understanding paradoxically low rates of self-harm in a socioeconomically disadvantaged community in London.

London has unexpectedly low overall rates of self-harm in public health data and contains highly deprived areas with these paradoxically low rates. Qualitative data were collected via interviews and focus groups with 26 individuals living and working in one such area. Using the Stress Process Model, we explore why this ethnically diverse community, which is exposed to multiple, chronic stressors, might nonetheless appear to have low rates of self-harm. Participants described significant impacts of stressors on the mental health of people locally. These were partly buffered by social resources related to community solidarity and a culture of self-reliance. However, identifying oneself as mentally ill through being known to have self-harmed was seen as highly risky, diminishing a person’s social status and exposing them to additional stressors from the community and services. Consequently, people tended to hide distress, respond with behaviors less linked to mental illness and avoid mental health services

Axial length growth and the risk of developing myopia in European children

PURPOSE: To generate percentile curves of axial length (AL) for European children, which can be used to estimate the risk of myopia in adulthood. METHODS: A total of 12 386 participants from the population-based studies Generation R (Dutch children measured at both 6 and 9 years of age; N = 6934), the Avon Longitudinal Study of Parents and Children (ALSPAC) (British children 15 years of age; N = 2495) and the Rotterdam Study III (RS-III) (Dutch adults 57 years of age; N = 2957) contributed to this study. Axial length (AL) and corneal curvature data were available for all participants; objective cycloplegic refractive error was available only for the Dutch participants. We calculated a percentile score for each Dutch child at 6 and 9 years of age. RESULTS: Mean (SD) AL was 22.36 (0.75) mm at 6 years, 23.10 (0.84) mm at 9 years, 23.41 (0.86) mm at 15 years and 23.67 (1.26) at adulthood. Axial length (AL) differences after the age of 15 occurred only in the upper 50%, with the highest difference within the 95th percentile and above. A total of 354 children showed accelerated axial growth and increased by more than 10 percentiles from age 6 to 9 years; 162 of these children (45.8%) were myopic at 9 years of age, compared to 4.8% (85/1781) for the children whose AL did not increase by more than 10 percentiles. CONCLUSION: This study provides normative values for AL that can be used to monitor eye growth in European children. These results can help clinicians detect excessive eye growth at an early age, thereby facilitating decision-making with respect to interventions for preventing and/or controlling myopia