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

Form factors and photoproduction amplitudes

We examine the use of phenomenological form factors in tree level amplitudes for meson photoproduction. Two common recipes are shown to be fundamentally incorrect. An alternate form consistent with gauge invariance and crossing symmetry is proposed.Comment: To be published in PR

Measurement of the Cross Section Asymmetry of the Reaction gp-->pi0p in the Resonance Energy Region Eg = 0.5 - 1.1 GeV

The cross section asymmetry Sigma has been measured for the photoproduction of pi0-mesons off protons, using polarized photons in the energy range Eg = 0.5 - 1.1 GeV. The CM angular coverage is Theta = 85 - 125 deg with energy and angle steps of 25 MeV and 5 deg, respectively. The obtained Sigma data, which cover the second and third resonance regions, are compared with existing experimental data and recent phenomenological analyses. The influence of these measurements on such analyses is also considered

Progress on Neutron-Target Multipoles above 1 GeV

We report a new extraction of nucleon resonance couplings using pi- photoproduction cross sections on the neutron. The world database for the process gn-->pi-p above 1 GeV has quadrupled with the addition of new differential cross sections from the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab in Hall B. Differential cross sections from CLAS have been improved with a new final-state interaction determination using a diagrammatic technique taking into account the SAID phenomenological NN and piN final-state interaction amplitudes. Resonance couplings have been extracted and compared to previous determinations. With the addition of these new cross sections, significant changes are seen in the high-energy behavior of the SAID cross sections and amplitudes.Comment: 4 pages, 3 figures, 1 table; talk given at 12th International Workshop on Meson Production, Properties and Interaction (MESON2012), 31 May - 5 June 2012, Krakow, Poland; will be published online in European Journal Web of Conference

Two-color holography concept (T-CHI)

The Material Processing in the Space Program of NASA-MSFC was active in developing numerous optical techniques for the characterization of fluids in the vicinity of various materials during crystallization and/or solidification. Two-color holographic interferometry demonstrates that temperature and concentration separation in transparent (T-CHI) model systems is possible. The experiments were performed for particular (succinonitrile) systems. Several solutions are possible in Microgravity Sciences and Applications (MSA) experiments on future Shuttle missions. The theory of the T-CHI concept is evaluated. Although particular cases are used for explanations, the concepts developed will be universal. A breadboard system design is also presented for ultimate fabrication and testing of theoretical findings. New developments in holography involving optical fibers and diode lasers are also incorporated

Coherent Pair State of Pion in Constituent Quark Model

A coherent state of pions is introduced to the nonrelativistic quark model. The coherent pair approximation is employed for the pion field in order to maintain the spin-isospin symmetry. In this approximation the pion is localized in the momentum space, and the vertex form factor in the pion-quark interaction is derived from this localization. The nucleon masses and wave functions are calculated using this model, and our results are compared to those of the quark model with the one pion exchange potential. Similar result is obtained for the mass spectrum, but there exists a clear difference in the internal structure of nucleon resonances.Comment: 17 pages, 2 figures, revtex, submitted to Phys. Rev.