Diurnal Refractive Error Fluctuations in Diabetic and Control Subjects

Purpose: Refractive error has been shown to fluctuate in poorly controlled diabetic patients. The purpose of this study was to measure acute diurnal fluctuations in refractive error and blood glucose levels (BGLs) in diabetic and control subjects. Methods: Twenty-one type 2 diabetic subjects (age 56 ± 11 years), 20 type 1 diabetic subjects (age 38 ± 15 years) and 20 non-diabetic controls (age 49 ± 23 years) took part in the study. Refractive error was measured with an OPD ARK-10000 autorefractometer (Nidek) and BGLs were measured using a finger stick test (Hemocue). All measurements were taken six times during the day, between 8AM and 8PM at approximately twohourly intervals. Using power vector analysis the variability in refractive error was mapped against time of day and related to BGLs, HbA1c, diabetic status and duration of disease. Results: Refractive error was similar between groups (p=0.96) and did not fluctuate significantly during the day in any of the three groups (ANOVA p>0.05). The mean ± SD values for BGLs during the day were 10.4 ± 4.40mM/l in DM type 2, 10.3 ± 5.30mM/l in DM type 1, and 5.4 ± 1.04mM/l in control subjects. BGLs changed significantly during the day and between groups (ANOVA p0.05). Multiple regression analysis showed that neither BGLs, HbA1c, diabetic status, nor duration of disease had a significant effect on diurnal refractive error measurements. (p>0.05). Conclusions: Diurnal changes in BGLs do not result in significant acute refractive error fluctuations in diabetic patients, as measured with an autorefractometer. CR: C. O’Donnell, None; H. Workman, None; S.L. Hosking, None; B. Huntjens, None. Support: Supported by a PhD studentship from Lein Applied Diagnostics Ltd

The Beta Generalized Exponential Distribution

We introduce the beta generalized exponential distribution that includes the beta exponential and generalized exponential distributions as special cases. We provide a comprehensive mathematical treatment of this distribution. We derive the moment generating function and the $r$th moment thus generalizing some results in the literature. Expressions for the density, moment generating function and $r$th moment of the order statistics also are obtained. We discuss estimation of the parameters by maximum likelihood and provide the information matrix. We observe in one application to real data set that this model is quite flexible and can be used quite effectively in analyzing positive data in place of the beta exponential and generalized exponential distributions

Improving efficiency of pig feed manufacturing and application of additives

The project has demonstrated that processed feeds with similar ingredient mixtures differ widely between mills in throughput, energy use, pellet hardness and durability and nutritional quality for growing pigs. Preparation of grains before mixing, specific ingredients and additives used as well as the physical structure of the processing units all affect the cost of manufacture and physical and nutritional quality of the finished product

Developing Intensity-Duration-Frequency (IDF) Curves From Satellite-Based Precipitation: Methodology and Evaluation

Given the continuous advancement in the retrieval of precipitation from satellites, it is important to develop methods that incorporate satellite-based precipitation data sets in the design and planning of infrastructure. This is because in many regions around the world, in situ rainfall observations are sparse and have insufficient record length. A handful of studies examined the use of satellite-based precipitation to develop intensity-duration-frequency (IDF) curves; however, they have mostly focused on small spatial domains and relied on combining satellite-based with ground-based precipitation data sets. In this study, we explore this issue by providing a methodological framework with the potential to be applied in ungauged regions. This framework is based on accounting for the characteristics of satellite-based precipitation products, namely, adjustment of bias and transformation of areal to point rainfall. The latter method is based on previous studies on the reverse transformation (point to areal) commonly used to obtain catchment-scale IDF curves. The paper proceeds by applying this framework to develop IDF curves over the contiguous United States (CONUS); the data set used is Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks – Climate Data Record (PERSIANN-CDR). IDFs are then evaluated against National Oceanic and Atmospheric Administration (NOAA) Atlas 14 to provide a quantitative estimate of their accuracy. Results show that median errors are in the range of (17–22%), (6–12%), and (3–8%) for one-day, two-day and three-day IDFs, respectively, and return periods in the range (2–100) years. Furthermore, a considerable percentage of satellite-based IDFs lie within the confidence interval of NOAA Atlas 14

Perinatal Cat and Dog Exposure and the Risk of Asthma and Allergy in the Urban Environment: A Systematic Review of Longitudinal Studies

Background. The literature is contradictory concerning pet exposure and the risk of development of asthma and other allergic diseases. Using longitudinal studies, we aimed to systematically review the impact of pet ownership in the critical perinatal period as a risk factor for allergies in childhood. Methods. Medline database was searched for urban cohort studies with perinatal exposure to cats and/or dogs and subsequent asthma or allergic disease. Results. Nine articles, comprising 6498 participants, met inclusion criteria. Six found a reduction in allergic disease associated with perinatal exposure to dogs or, cats or dogs. One study found no association. Two found increased risk only in high-risk groups. Conclusion. Longitudinal studies in urban populations suggest that perinatal pets, especially dogs, may reduce the development of allergic disease in those without a family history of allergy. Other unmeasured factors such as pet-keeping choices in allergic families may be confounding the association seen in these high-risk families, and further study is required

Diurnal Fluctuations in Higher-Order Aberrations in Patients with Diabetes Mellitus

Purpose: The purpose of this study was to investigate diurnal fluctuations in aberrations and blood glucose levels (BGLs) in diabetic patients and control subjects. Methods: Twenty-one type 2 diabetic subjects (age 56 ± 11 years), 20 type 1 diabetic subjects (age 38 ± 15 years) and 20 non-diabetic controls (age 49 ± 23 years) took part in the study. The distribution of refractive errors was similar between groups (p=0.96). Aberrations were measured with an OPD autorefractometer (NIDEK) and analysed for a 5mm pupil diameter. BGLs were measured using a finger stick test (Hemocue). All measurements were taken six times during the day, between 8AM and 8PM at approximately two-hourly intervals. Results: The coefficients of third order coma, fourth order spherical aberration, and higher-order RMS error were found to be higher in the diabetic compared to the control group. The mean variation in the third and fourth order aberrations over the twelve-hour period was found to be higher in the diabetic when compared to the control group; however, these differences were not statistically significant. The higher-order RMS error showed a negative correlation with time in the diabetic group compared to a positive correlation in the control group (gradient: -6.4 x 10-3 in type 2 diabetes, -24.4 x 10-3 in type 1 diabetes and 74.9 x 10-3 in control group; ANOVA p=0.025). In diabetic patients, increasing BGLs showed a negative trend with the third order horizontal coma (p=0.44) and fourth order spherical aberration coefficients (p= 0.61), while a positive trend was observed between BGLs and the third order vertical coma (p=0.58) and higher order RMS (p=0.47). Conclusions: Compared to controls, diabetic patients exhibit greater variation in higher order aberrations. Ocular aberration coefficients varied during the day, with fluctuating BGLs. The variation in ocular aberration coefficients is possibly due to the effect of large fluctuations in BGLs leading to hydration effects on the diabetic crystalline lens. CR: B. Huntjens, None; H. Radhakrishnan, None; H. Workman, None; S.L. Hosking, None; C. O’Donnell, None. Support: Supported by a PhD studentship from Lein Applied Diagnostics Lt