32 resultados para First Intermediate Period
em Aston University Research Archive
Resumo:
We study the effects of temperature and strain on the spectra of the first and second-order diffraction attenuation bands of a single long-period grating (LPG) in step-index fibre. The primary and second-order attenuation bands had comparable strength with the second-order bands appearing in the visible and near-infra red parts of the spectrum. Using first and second-order diffraction to the eighth cladding mode a sensitivity matrix was obtained with limiting accuracy given by cross-sensitivity of ~1.19% of the measurement. The sensing scheme presented as a limiting temperature and strain resolution of ±0.7 °C and ~±25 µ.
Resumo:
We study the effects of temperature and strain on the spectra of the first and second-order diffraction attenuation bands of a single long-period grating (LPG) in step-index fibre. The primary and second-order attenuation bands had comparable strength with the second-order bands appearing in the visible and near-infra red parts of the spectrum. Using first and second-order diffraction to the eighth cladding mode a sensitivity matrix was obtained with limiting accuracy given by cross-sensitivity of ∼ 1.19% of the measurement. The sensing scheme presented as a limiting temperature and strain resolution of ± 0.7 °C and ∼ ± 25 με. © 2002 Elsevier Science B.V. All rights reserved.
Resumo:
We report on the first recording of a periodic structure of ∼150 nm pitch in a permanently moving sample of a pure fused silica using the tightly focused, 82 nJ, 267 nm, 300 fs, 1 kHz laser pulses. © 2007 IOP Publishing Ltd.
Resumo:
Long-period fibre gratings (LPGs) have previously been used to detect quantities such as temperature, strain and refractive index (RI). The responsivity to surrounding refractive index means that, potentially, LPGs could be realised as optical biosensors for applications in biochemical and biomedical application areas. We report here to our best knowledge the first investigation on refractive index sensing properties of LPGs with sol-gel derived titanium and silicon oxide coatings. It is revealed that the RI sensitivity of an LPG is affected by both the thickness and the index value of the coating; the coating with higher index and thickness will enhance the LPG RI sensitivity significantly. The surrounding refractive index induced LPG resonance shift has been evaluated over the LPGs’ most sensitive RI region from 1.42 to 1.44. We have identified that, in this region, the uncoated LPG has an RI sensitivity of (-673.0±0.4)nm/uri (unit of refractive index) while the LPG coated with titanium oxide exhibits a sensitivity as high as (-1067.15±0.04)nm/uri.
Resumo:
This paper analyses the impact of FDI on the employment, productivity, profitability and survival performance of urban SOEs in China, with the aid of a rich panel data set over the period 1999–2005. Our estimation strategy controls for the endogeneity of a number of regressors and accounts for firm-level unobserved heterogeneity. Four key results emerge from the analysis: (i) Firmlevel foreign finance enhances the employment and productivity growth of SOEs, as well as their survival prospects; (ii) Competition from sectoral FDI has a deleterious impact on the growth and survival probability of SOEs without access to any foreign capital; (iii) Export-oriented FDI in downstream sectors has negative performance ramifications; and (iv) There are no discernible spillover effects that can be attributed to FDI in upstream sectors, suggesting limited linkages between multinational firms and SOEs.
Resumo:
Purpose - To provide a framework of accounting policy choice associated with the timing of adoption of the UK Statement of Standard Accounting Practice (SSAP) No. 20, "Foreign Currency Translation". The conceptual framework describes the accounting policy choices that firms face in a setting that is influenced by: their financial characteristics; the flexible foreign exchange rates; and the stock market response to accounting decisions. Design/methodology/approach - Following the positive accounting theory context, this paper puts into a framework the motives and choices of UK firms with regard to the adoption or deferment of the adoption of SSAP 20. The paper utilises the theoretical and empirical findings of previous studies to form and substantiate the conceptual framework. Given the UK foreign exchange setting, the framework identifies the initial stage: lack of regulation and flexibility in financial reporting; the intermediate stage: accounting policy choice; and the final stage: accounting choice and policy review. Findings - There are situations where accounting regulation contrasts with the needs and business objectives of firms and vice-versa. Thus, firms may delay the adoption up to the point where the increase in political costs can just be tolerated. Overall, the study infers that firms might have chosen to defer the adoption of SSAP 20 until they reach a certain corporate goal, or the adverse impact (if any) of the accounting change on firms' financial numbers is minimal. Thus, the determination of the timing of the adoption is a matter which is subject to the objectives of the managers in association with the market and economic conditions. The paper suggests that the flexibility in financial reporting, which may enhance the scope for income-smoothing, can be mitigated by the appropriate standardisation of accounting practice. Research limitations/implications - First, the study encompassed a period when firms and investors were less sophisticated users of financial information. Second, it is difficult to ascertain the decisions that firms would have taken, had the pound appreciated over the period of adoption and had the firms incurred translation losses rather than translation gains. Originality/value - This paper is useful to accounting standards setters, professional accountants, academics and investors. The study can give the accounting standard-setting bodies useful information when they prepare a change in the accounting regulation or set an appropriate date for the implementation of an accounting standard. The paper provides significant insight about the behaviour of firms and the associated impacts of financial markets and regulation on the decision-making process of firms. The framework aims to assist the market and other authorities to reduce information asymmetry and to reinforce the efficiency of the market. © Emerald Group Publishing Limited.
Resumo:
Neuronal intermediate filament (IF) inclusion disease (NIFID) is characterized by neuronal loss, neuronal cytoplasmic IF-positive inclusions (NI), swollen neurons (SN), and a glial cell reaction. We studied the spatial correlations between the clusters of NI, SN, and glial cells in four gyri of the temporal lobe (superior temporal gyrus, inferior temporal gyrus, lateral occipitotemporal gyrus, and parahippocampal gyrus) in four cases of NIFID. The densities of histological features (per 50x250 μ sample field) were as follows: NI (mean = 0.41, range 0.28-0.68), SN (mean = 1.41, range 0.47-2.65), glial cell nuclei (mean = 5.21, range 3.63-8.17). The NI and the SN were positively correlated in half of the brain regions examined, the correlations being present at the smallest field size (50x250 μm). The NI were also positively or negatively correlated with the glial cell nuclei in different areas, the negative correlations being present at the smallest field size. Glial cell nuclei were positively or negatively correlated with the SN in different brain areas, mainly at the larger field sizes (400x250 and 800x250 μm). The spatial correlation between the clusters of NI and SN in the cortex suggests their development within the same columns of cells. At first, the glial cell reaction is also confined to these columns but later becomes more generally distributed across the cortex. © Springer-Verlag 2004.
Resumo:
Purpose To evaluate the effect of latanoprost 0.005% on the optic nerve head (ONH) and retinal circulation of newly diagnosed and previously untreated primary open-angle glaucoma (POAG) patients. Methods Twenty-two newly diagnosed and previously untreated POAG patients (mean age±SD: 68.38±11.92 years) were included in this longitudinal open-label study. Patients were treated with latanoprost 0.005% once a day. Intraocular pressure (IOP), systemic blood pressure (BP), mean ocular perfusion pressure (MOPP), and ocular perfusion parameters ‘volume’, ‘velocity’, and ‘flow’ measured at the optic nerve head (ONH) and retina by means of Heidelberg Retina Flowmeter system were evaluated during a 6-month follow-up period. Results Treatment with latanoprost 0.005% resulted in a significant decrease in IOP (P<0.0001) and increase in MOPP (P<0.0001). After correcting for changes in MOPP, the blood velocity measured at the ONH level was significantly higher after 6 months of treatment than at baseline (P=0.0310). In addition, blood volume and flow measured at the peripapillary retina level improved after 3 and 6 months of treatment (P=0.0170; P=0.0260, and P=0.0170; P=0.0240 respectively). Conclusion Previously untreated POAG patients exhibit reduced IOP, increased MOPP and improved ocular perfusion at the ONH and retina levels when treated with Latanoprost 0.005%. These effects could be beneficial for glaucoma patients suffering from ocular vascular dysregulation.
Resumo:
Long period gratings (LPGs) were written into a D-shaped optical fibre that has an elliptical core with a W-shaped refractive index profile and the first detailed investigation of such LPGs is presented. The LPGs’ attenuation bands were found to be sensitive to the polarisation of the interrogating light with a spectral separation of about 15 nm between the two orthogonal polarisation states. A finite element method was successfully used to model many of the behavioural features of the LPGs. In addition, two spectrally overlapping attenuation bands corresponding to orthogonal polarisation states were observed; modelling successfully reproduced this spectral feature. The spectral sensitivity of both orthogonal states was experimentally measured with respect to temperature and bending. These LPG devices produced blue and red wavelength shifts depending upon the orientation of the bend with measured maximum sensitivities of -3.56 and +6.51 nm m, suggesting that this type of fibre LPG may be useful as a shape/bend orientation sensor with reduced errors associated with polarisation dependence. The use of neighbouring bands to discriminate between temperature and bending was also demonstrated, leading to an overall curvature error of ±0.14 m-1 and an overall temperature error of ±0.3 °C with a maximum polarisation dependence error of ±8 × 10-2 m-1 for curvature and ±5 × 10-2 °C for temperature.
Resumo:
The fabrication of sub-micron periodic structures beyond diffraction limit is a major motivation for the present paper. We describe the fabrication of the periodic structure of 25 mm long with a pitch size of 260 nm which is less than a third of the wavelength used. This is the smallest reported period of the periodic structure inscribed by direct point-by-point method. A prototype of the add-drop filter, which utilizes such gratings, was demonstrated in one stage fabrication process of femtosecond inscription, in the bulk fused silica.
Resumo:
A long period grating was photoinscribed step-by-step in microstructured poly(methyl methacrylate) fiber for the first time using a continuous wave HeCd laser at 325 nm, irradiating the fiber with a power of 1 mW. The grating had a length of 2 cm and a period of 1 mm. A series of cladding mode coupling resonances were observed throughout the spectral region studied of 600 to 1100 nm. The resonance wavelengths were shown to be sensitive to the diffusion of water into the fiber.
Resumo:
The fabrication of sub-micron periodic structures beyond diffraction limit is a major motivation for the present paper. We describe the fabrication of the periodic structure of 25 mm long with a pitch size of 260 nm which is less than a third of the wavelength used. This is the smallest reported period of the periodic structure inscribed by direct point-by-point method. A prototype of the add-drop filter, which utilizes such gratings, was demonstrated in one stage fabrication process of femtosecond inscription, in the bulk fused silica.
Resumo:
We report on the first recording of a periodic structure of ~150 nm pitch in a permanently moving sample of a pure fused silica using the tightly focused, 82 nJ, 267 nm, 300 fs, 1 kHz laser pulses.
Resumo:
Long-period fibre gratings (LPGs) have previously been used to detect quantities such as temperature, strain, and refractive index (RI). We report here, to the best of our knowledge, the first investigation on refractive index sensing properties of LPGs with sol–gel derived titanium and silicon oxide coatings. It is revealed that the RI sensitivity of an LPG is affected by both the thickness and the index value of the coating; a coating with higher index and thickness will enhance the LPG RI sensitivity significantly. The surrounding refractive index induced LPG resonance shift has been evaluated over the LPGs' most sensitive RI region from 1.42 to 1.44. We have identified that, in this region, the uncoated LPG has an RI sensitivity of (-673.0 ± 0.4) nm/uri (unit of refractive index) while the LPG coated with titanium oxide exhibits a sensitivity as high as (-1067.15 ± 0.04) nm/uri. The experimental results also reveal that, even in the RI insensitive region around 1.33, there still is a marked enhancement in RI sensitivity of the sol–gel coated LPG compared to the uncoated one. This is potentially significant as coated LPGs may be extended to low RI gas and semi-liquidized based sensing applications.
Resumo:
The Government has established essential principles in order to make significant improvements in the health of the people and has placed an emphasis on shifting care to the primary sening. This research has explored the potential role of the community pharmacist in health promotion in the pharmacy, and at general medical practices. The feasibility of monitoring patients' health status in the community was evaluated by intervention to assess and alter cardiovascular risk factors.68, hypertensive patients, monitored at one surgery, had a change in mean systolic blood pressure from 158.28 to 146.55 mmHg, a reduction of 7.4%, and a change in mean diastolic bood pressure from 90.91 to 84.85 mmHg, a reduction of 6.7%.120 patients, from a cohort of 449 at the major practice, with an initial serum total cholesterol of 6.0+mmol/L, experienced a change in mean value from 6.79 to 6.05 mmol/L, equivalent to a reduction of 10.9%. 86% of this patient cohort showed a decrease in cholesterol concentration. Patients, placed in a high risk category according to their coronary rank score, assessed at the first health screening, showed a consistent and significant improvement in coronary score throughout the study period of two years. High risk and intermediate risk patients showed improvements in coronary score of 52% and 14% respectively. Patients in the low risk group maintained their good coronary score. In some cases, a patient's improvement was effected in liaison with the GP, after a change or addition of medication and/or dosage.Pharmacist intervention consisted of advice on diet and lifestyle and adherence to medication regimes. It was concluded that a pharmacist can facilitate a health screening programme in the primary care setting, and provide enhanced continuity of care for the patient.