936 resultados para short-2
Resumo:
Purpose: This work investigates how short-term changes in blood glucose concentration affect the refractive components of the diabetic eye in patients with long-term Type 1 and Type 2 diabetes. Methods: Blood glucose concentration, refractive error components (mean spherical equivalent MSE, J0, J45), central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), axial length (AL) and ocular aberrations were monitored at two-hourly intervals over a 12-hour period in: 20 T1DM patients (mean age ± SD) 38±14 years, baseline HbA1c 8.6±1.9%; 21 T2DM patients (mean age ± SD) 56±11 years, HbA1c 7.5±1.8%; and in 20 control subjects (mean age ± SD) 49±23 years, HbA1c 5.5±0.5%. The refractive and biometric results were compared with the corresponding changes in blood glucose concentration. Results: Blood glucose concentration at different times was found to vary significantly within (p<0.0005) and between groups (p<0.0005). However, the refractive error components and ocular aberrations were not found to alter significantly over the day in either the diabetic patients or the control subjects (p>0.05). Minor changes of marginal statistical or optical significance were observed in some biometric parameters. Similarly there were some marginally significant differences between the baseline biometric parameters of well-controlled and poorly-controlled diabetic subjects. Conclusion: This work suggests that normal, short-term fluctuations (of up to about 6 mM/l on a timescale of a few hours) in the blood glucose levels of diabetics are not usually associated with acute changes in refractive error or ocular wavefront aberrations. It is therefore possible that factors other than refractive error fluctuations are sometimes responsible for the transient visual problems often reported by diabetic patients. © 2012 Huntjens et al.
Resumo:
This is the first volume to capture the essence of the burgeoning field of cultural studies in a concise and accessible manner. Other books have explored the British and North American traditions, but this is the first guide to the ideas, purposes and controversies that have shaped the subject. The author sheds new light on neglected pioneers and a clear route map through the terrain. He provides lively critical narratives on a dazzling array of key figures including, Arnold, Barrell, Bennett, Carey, Fiske, Foucault, Grossberg, Hall, Hawkes, hooks, Hoggart, Leadbeater, Lissistzky, Malevich, Marx, McLuhan, McRobbie, D Miller, T Miller, Morris, Quiller-Couch, Ross, Shaw, Urry, Williams, Wilson, Wolfe and Woolf. Hartley also examines a host of central themes in the subject including literary and political writing, publishing, civic humanism, political economy and Marxism, sociology, feminism, anthropology and the pedagogy of cultural studies.
Resumo:
This article presents the findings of a study of the psychological variables that discriminate between high and low omitters on a high-stakes achievement test using a short-response format. Data were obtained from a questionnaire administered to a random sample (N = 1,908) of students prior to sitting the 1997 Queensland Core Skills (QCS) Test (N = 29,273). Fourteen psychological variables were measured including test anxiety (four subscales), emotional stability, achievement motivation, self-esteem, academic self-concept, self-estimate of ability, locus of control (three subscales), and approaches to learning (two subscales). The results were analyzed using descriptive discriminant analysis and suggested that the psychological predictors of the propensity to omit short-response items include test-irrelevant thinking and academic self-concept, with sex of candidate being a mediating variable.
Resumo:
The overall rate of omission of items for 28,331 17 year old Australian students on a high stakes test of achievement in the common elements or cognitive skills of the senior school curriculum is reported for a subtest in multiple choice format and a subtest in short response format. For the former, the omit rates were minuscule and there was no significant difference by gender or by type of school attended. For the latter, where an item can be 'worth' up to five times that of a single multiple choice item, the omit rates were between 10 and 20 times that for multiple choice and the difference between male and female omit rate was significant as was the difference between students from government and non-government schools. For both formats, females from single sex schools omitted significantly fewer items than did females from co-educational schools. Some possible explanations of omit behaviour are alluded to.
Resumo:
In the structure of the 1:1 proton-transfer compound of 1,10-phenanthroline with 4,5-dichlorophthalic acid, C12H9N2+ C8H3Cl2O4-, determined at 130 K, the 1,10-phenanthroline cation and the hydrogen 4,5-dichlorophthalate anion associate through a single N-H...O(carboxyl) hydrogen bond giving discrete units which have no extension except through a number of weak cation C-H...O(anion) associations and weak cation--anion aromatic ring pi-pi interactions [minimum centroid separation, 3.6815(12)A]. The anions are essentially planar [maximum deviation 0.214(1)A (a carboxyl O)] with the syn-related H atom of the carboxyl group forming a short intramolecular O-H...O(carboxyl) hydrogen bond.
Resumo:
In both developed and developing countries, increased prevalence of obesity has been strongly associated with increased incidence of type 2 diabetes mellitus (T2DM) in the adult population. Previous research has emphasized the importance of physical activity in the prevention and management of obesity and T2DM, and generic exercise guidelines originally developed for the wider population have been adapted for these specific populations. However, the guidelines traditionally focus on aerobic training without due consideration to other exercise modalities. Recent reviews on resistance training in the T2DM population have not compared this modality with others including aerobic training, or considered the implications of resistance training for individuals suffering from both obesity and T2DM. In short, the optimal mix of exercise modalities in the prescription of exercise has not been identified for it benefits to the metabolic, body composition and muscular health markers common in obesity and T2DM. Similarly, the underlying physical, social and psychological barriers to adopting and maintaining exercise, with the potential to undermine the efficacy of exercise interventions, have not been addressed in earlier reviews. Because it is well established that aerobic exercise has profound effects on obesity and T2DM risk, the purpose of this review was to address the importance of resistance training to obese adults with T2DM.
Resumo:
In the structure of the 1:1 proton-transfer compound of isopropylamine with 4,5-dichlorophthalic acid, C3H10N+·C8H3Cl2O4-, the three cation H-atom donors associate with three separate carboxyl O-atom anion acceptors, giving conjoint cyclic R44(12), R44(16) hydrogen-bonding cation-anion interactions in a one-dimensional ribbon structure. In the anions, the carboxyl groups lie slightly out of the plane of the benzene ring [maximum deviations = 0.439 (1) for a carboxylic acid O atom and 0.433 (1) Å for a carboxylate O atom]. However, the syn-related proton of the carboxylic acid group forms the common short intramolecular O-HOcarboxyl hydrogen bond.
Resumo:
New composite doped poly (ethylene oxide) polymer electrolyte was developed using 2-mercapto benzimidazole as plasticizer and iodide/triiodide as redox couple. The fabrication of the cell involves Poly(ethylene oxide)/ 2-mercapto benzimidazole / iodide/triiodide as polymer electrolyte in dye-sensitized solar cell fabricated with N3 dye and TiO2 nanoparticles as the photoanode and Platinum coated FTO (fluorine doped SnO2) as counter electrode. The current-volatage characteristics under simulated sunlight AM1.5 shows a short circuit current Isc of 8.7mA and open circuit photovoltage 508 mV. The conductivity measurements for the new polymer electrolyte and the photoelectrochemical measurments were carried out systematically. In 2-mercapto benzimidazole the electron rich sulphur and nitrogen atoms, act as pi-electron donors that form good interaction with iodine which plays a vital role in the performance of the fabricated dye-sensitized solar cells. The resonance effect increases the stability of the cell to a considerable extent. These results suggest that the new composite polymer electrolyte performs as a promising new doped polymer-electrolyte.
Resumo:
The crystal structure of the modified unsymmetrically N, N'-substituted viologen chromophore, N-ethyl- N'-(2-phosphonoethyl)-4, 4'-bipyridinium dichloride 0.75 hydrate. (1) has been determined. Crystals are triclinic, space group P-1 with Z = 2 in a cell with a = 7.2550(1), b = 13.2038(5), c = 18.5752(7) Å, α = 86.495(3), β = 83.527(2), γ = 88.921(2)o. The two independent but pseudo-symmetrically related cations in the asymmetric unit form one-dimensional hydrogen-bonded chains through short homomeric phosphonic acid O-H...O links [2.455(4), 2.464(4)A] while two of the chloride anions are similarly strongly linked to phosphonic acid groups [O-H…Cl, 2.889(4), 2.896(4)Å]. The other two chloride anions together with the two water molecules of solvation (one with partial occupancy) form unusual cyclic hydrogen-bonded bis(Cl...water) dianion units which lie between the layers of bipyridylium rings of the cation chain structures with which they are weakly associated.
Resumo:
In the structure of the 1:1 proton-transfer compound of 4-methylpyridine (\g-picoline) with 4,5-dichlorophthalic acid, C6H8N+ C8H3Cl2O4- . H2O, determined at 200 K, the 4,5-dichlorophthalate anions are bridged by the water molecule through O--H...O~carboxyl~ hydrogen bonds, giving zig-zag chains which extend along the c axial direction of the unit cell. The 4-methylpyridine cations are linked to the chains through single N--H...O~water~ hydrogen bonds and occupy the voids within the chains in the one-dimensional structure. The anions have the common 'planar' conformation with the short intramolecular O--H...O(carboxyl) hydrogen bond.