This paper estimates aggregate import demand elasticities for five major oil—exporting countries for the period 1960–1982. The results are consistent across the five countries with regard to the ...income—elasticty of demand. Real GDP is positively associated with import demand in all five countries, with an average elasticity of approximately 1.5. Somewhat less consistent results are obtained for the importance of relative prices or separately, the import and domestic price indices, in determining import demand. Nevertheless, there is strong statistical evidence that relative prices influence real imports in Saudi Arabia, Mexico, and Venezuala, with price—elastic demand for the first two, and price inelastic demand for the latter.
A general HDL-A model of a DC-DC switching regulator core Palumbo, G.; Torrisi, D.; Ursino, R.
ICECS'99. Proceedings of ICECS '99. 6th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.99EX357),
1999, Letnik:
3
Conference Proceeding
A general and accurate HDL-A model of a DC-DC switching regulator core is presented. It works both in continuous and discontinuous conduction mode. The model was validated comparing it with Spice ...simulations. The results show accuracy with an high computational time efficiency. Indeed, to achieve the same results a time lower than 1% of the one required by Spice is used. Despite the proposed model was developed assuming PWM control, it can be simply extended to PFM. Moreover, the model is also able to evaluate the stability of the switching regulator system in the frequency domain.
To evaluate outcome at 5 1/2 years after randomization in eyes that underwent cryotherapy and in control eyes of patients in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity.
...During infancy, patients with bilateral threshold retinopathy of prematurity (ROP) were assigned to receive cryotherapy for one eye and no cryotherapy for the other eye. Those with threshold ROP in only one eye (asymmetric) were randomly assigned to cryotherapy or no cryotherapy for that eye. Then, 5 1/2 years later, testers who were masked to the treatment status of each eye measured the patients' monocular visual acuity by using the log of the minimum angle of resolution visual acuity chart that was used in the Early Treatment of Diabetic Retinopathy Study. This was the most refined visual acuity testing yet performed on this cohort. Structural outcome was evaluated by participating ophthalmologists' assessment of ROP residua in the posterior pole of the fundus.
Patients were 291 children who had been preterm infants with birth weights of less than 1251 g in whom threshold ROP had developed. Two hundred forty patients had bilateral threshold ROP, and 51 had threshold ROP in only one eye.
For the 234 children examined, both visual acuity and fundus structure showed a reduction in unfavorable outcomes in treated vs control eyes: 47.1% vs 61.7%, respectively (P<.005), for visual acuity and 26.9% vs 45.4%, respectively (P<.001), for fundus status. Detailed analysis of visual acuity outcomes for all eyes revealed that while fewer treated eyes (31.5%) than control eyes (48%) were blind (P<.001), there was a slight trend toward fewer eyes with a visual acuity of 20/40 or better in the treated (13%) vs control (17%) groups (P=.19).
The results support the long-term efficacy and safety of cryotherapy in the treatment of severe ROP. However, the data show preliminary evidence of a possible adverse effect of this treatment on visual acuity.
A new PSpice model of punch-through (PT) IGBTs is developed to account for the presence of the buffer layer and its influence on the dynamic behavior of the device. The recombination and ...redistribution of charge in the base region of IGBTs during a transient behavior are modeled and represented by equivalent electric circuits. In particular, the effect of the external voltage (clamping voltage) on the tail current decay is modeled. Besides, phenomena such as the "tail bump" and the variation of the slope in the initial part of the output voltage V/sub ce/ during a turn-off transient are modeled. The proposed model is validated by comparing several simulation runs to the experimental traces at different static and dynamic working conditions.
The Authors analyse possible parameters of cytological evaluation which can be used for the grading of endometrial hyperplasias and the diagnostic differentiation between atypical hyperplasia and ...adenocarcinoma. They consider 77 women who underwent endometrial cytology by aspiration just before diagnostic examination of the uterine cavity. Results show that in atrophic endometrium desquamation in clusters of less than 100 cells prevails whereas proliferative and secretory endometrium presents mainly clusters of 100-500 regularly stratified cells. Hyperplasia show progressive increase in isolated cells; "branched" glands appear rarely in hyperplasia with minimal atypia while prevailing in hyperplasia with severe atypia and adenocarcinoma. Simple layers prevail in atrophic endometrium, stratified regular layers prevail in proliferative and secretory endometrium; three-dimensional clusters appear in hyperplasia with minimal atypia and become significant with severe atypia. Adenocarcinoma is characterized by haematic and necrotic background, high percentage of isolated cells and prevalence of clusters of less than 100 cells, mainly three-dimensional. In addition it shows a significant incidence of papillary and rosette-like arrangements and abnormal cytoplasmic vacuolization.
Reconstructions with aesthetical materials neither finished nor polished can be extremely irregular and wrinkled. For this reason they represent an ideal basis for the growing of pigmentation which ...come from food remainings and the nestle of bacteria on the plaque. The finishing of aesthetical materials is a fundamental step in conservative dentistry. The finishing session regarding the aesthetical restorations should be considered and planned at the moment of their insertion in the prepared hollows. The finishing should not be considered an option, but the conclusion of all the conservative treatment. Purpose of the search is to examine and assess, through a technical equipment measuring the superficial wrinkledness of the materials, the action of 4 systems of finishing and polishing on two aesthetical materials widely used in the daily practice by dental surgeons: a compomer (Compoglass, Vivadent) and a composite (Spectrum, Dentsply).
For each of these two materials some little slabs model have been prepared, choosing the universal colour in the colorimetric scale. The two types of filling materials have been compared with 4 systems of finishing and polishing: Sof-Lex Pop-on (3M), Enhance system (Dentsply), Hawe Micro Disc (Howe Neos), Heawe Gommini Polisher (Heawe Neos). The total working time did not overcome 1 minute. The little slabs have been obtained, pressing the resin between two slides used in microscopy. In the hope to guarantee in the different samples, a uniform thickness, we have used a technical device. On each covering slide we have put a weight of 0.5 kg for 5 minutes. The thickness of the little slabs obtained was 2 mm. Thus, pressed between the two slides, the aesthetical material has been photopolymerized according to the time suggested by Manufacturing Industries. The sizes concerning the wrinkledness of samples subjected to different treatments have been carried out using a pointed profilometer with high sensitivity. (Tencor-P10). This instrument used in the National Laboratory of Catania, called INFN, is able to graphitize the wrinkledness of a surface "survbeying" it with a diamond ultramicrometric point.
All tested systems gradually produce the upper layers of the materials less suitable to resist the assault of plaque bacteria as time passed. The 3M coarse and medium grain Disks are very abrasive and for this reason the surface of the materials is ill-shaped. Those disks with fine and extra fine grain, smooth the tracks left by previous disks. As they have been always used according to their decreasing granulometry, the disks are used only for removing small composite pieces in excess and to improve micromorphology of the restauration. The "Gommini" are less abrasive than Disks. In a few minutes and often with only one step they produce a much regular and polished fillings surface.
The "Gommini" have a preference when the last photopolymerization has left a regular layer, with a very good micromorphology. Actually, "Gommini" do not remove much material, but they continue to smooth the outline of the reconstruction. Disks are not classified as being of first quality in the finishing of composites and compomers.
The authors reported a case of a child suffering from Cow's milk protein allergy, in which a soybean milk was administered for one month. The incorrect preparation of the formula determined a ...megaloblastic anaemia due to folate deficiency. The observation of very high levels of seric aminoacids during the acute phase of the disease was noteworthy. The therapy with folic acid and the introduction of protein hydrolysated formula milk determined a rapid normalization of the haematological picture. During the follow-up the administration of soybean protein caused anaphylaxis showing the contemporary presence of soybean allergy. The challenge test with cow's milk performed afterwards showed the restoration of the tolerance towards cow's milk protein.
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