An improved electronic circuit for tracing the I-V characteristics of photovoltaic modules and strings

This paper presents an improved electronic circuit for testing photovoltaic (PV) modules or strings by tracing their I-V and P-V characteristics. It consists of an electronic fast varying load based on a power MOSFET controlled by means of an innovative sweeping gate-source voltage in order to improve the tracing of the I-V characteristics on an oscilloscope. In order to prevent damage of data acquisition systems and mainly for use with high voltage PV strings, galvanic isolation is introduced for the sweeping signal as well as current and voltage measurements. In spite of this improved characteristics, the developed electronic circuit keeps the advantages of low cost and simplicity. Experimental results obtained with the electronic circuit are presented

Testing Intra-Industry Trade Between Portugal and Spain [1990-1996]

This paper shows how, in the period 1990-1996, economic integration between the two Iberian economies has deepened through intra-industry trade. The enquiry was led at the level of the main forty traded products. In this context, several tests have been made. Our analysis combines first the application of the Grubel and Lloyd index of the main forty products and the marginal intra-industry trade of Brulhart, and Brulhart and Elliot. On the basis of these indexes we defined our criterion for the selection of the competitive cluster of Portugal throughout the period. We have also considered the global intra-industry trade, in nominal and real terms, according to the method of Greenaway et al. In econometric terms we have tried to know which is the relation between the intra-industry trade index and the marginal intra-industry trade at the level of the main forty products, the results however were not unequivocal. The same is true as far as concerns the relation between the intra-industry trade index and the net export position at the level of the same products. Despite the fact that some attempts have been inconclusive, knowledge about Iberian trade has developed in a field essential to its upgrading, and the way is open for further research.intra-industry trade; marginal intra-industry trade; competitive cluster; net export position.

Chiral properties of discrete Joyce and Hestenes equations

This paper concerns the question of how chirality is realized for discrete counterparts of the Dirac-K\"{a}hler equation in the Hestenes and Joyce forms. It is shown that left and right chiral states for these discrete equations can be described with the aid of some projectors on a space of discrete forms. The proposed discrete model admits a chiral symmetry. We construct discrete analogues of spin operators, describe spin eigenstates for a discrete Joyce equation, and also discuss chirality.Comment: 14 pages, conference pape

Exports, productivity and innovation : evidence from Portugal using microdata

This study examines the evolution of Portuguese exports to Spain and its determinants in the period 2004-2008, based on a sample of the 97 largest exporters to Spain. The econometric study, using panel data and a static and dynamic analysis, considers as theoretically relevant explanatory variables productivity, equity capital, remuneration and innovation measured by the expenditure on research and development (R&D). The static results of the estimated models confirm the positive influence of productivity and equity capital on the variation of exports, and the negative effect of the labour costs. The variable R&D is statistically significant, with a positive effect on Portuguese exports in the dynamic model. The dynamic estimations also suggest that the exports in the previous period have a positive effect on contemporaneous exports

Testing intra-industry trade between Portugal and Spain 1990-1996

This paper shows how, in the period 1990-1996, economic integration between the two Iberian economies has deepened through intra-industry trade. The enquiry was led at the level of the main forty traded products. In this context, several tests have been made. Our analysis combines first the application of the Grubel and Lloyd index of the main forty products and the marginal intra-industry trade of Brulhart, and Brulhart and Elliot. On the basis of these indexes we defined our criterion for the selection of the competitive cluster of Portugal throughout the period. We have also considered the global intra-industry trade, in nominal and real terms, according to the method of Greenaway et al. In econometric terms we have tried to know which is the relation between the intra-industry trade index and the marginal intra-industry trade at the level of the main forty products, the results however were not unequivocal. The same is true as far as concerns the relation between the intra-industry trade index and the net export position at the level of the same products. Despite the fact that some attempts have been inconclusive, knowledge about Iberian trade has developed in a field essential to its upgrading, and the way is open for further research

Comparison of inverse planning systems based on biological or physical factors: Pinnacle®, Corvus® and Monaco®

Radiotherapy (RT) is one of the most important approaches in the treatment of cancer and its performance can be improved in three different ways: through the optimization of the dose distribution, by the use of different irradiation techniques or through the study of radiobiological initiatives. The first is purely physical because is related to the physical dose distributiuon. The others are purely radiobiological because they increase the differential effect between the tumour and the health tissues. The Treatment Planning Systems (TPS) are used in RT to create dose distributions with the purpose to maximize the tumoral control and minimize the complications in the healthy tissues. The inverse planning uses dose optimization techniques that satisfy the criteria specified by the user, regarding the target and the organs at risk (OAR’s). The dose optimization is possible through the analysis of dose-volume histograms (DVH) and with the use of computed tomography, magnetic resonance and other digital image techniques

Rastreio da Diabetes em Doentes com Doença Macrovascular Coronária: As Novas Guidelines Europeias são um Retrocesso?

BACKGROUND: The new European guidelines on diabetes mellitus and cardiovascular diseases propose that the FINnish Diabetes RIsk SCore should be used to evaluate the risk of diabetes mellitus and that diabetes mellitus screening in coronary artery disease patients should be based on fasting glucose and HbA1c. The 2 hour oral glucose tolerance test, recommended for all pts in the previous guidelines, is now only recommended for 'inconclusive' cases. We aimed to evaluate this new strategy. MATERIAL AND METHODS: Fasting glucose, HbA1c and glucose tolerance test (75 g, 2h) were prospectively evaluated in a consecutive group of pts with coronary artery disease. ADA criteria (both glucose tolerance test and HbA1c) were used to define diabetes mellitus and pre-diabetes mellitus. Diabetes mellitus risk was evaluated according to the FINnish Diabetes RIsk SCore. RESULTS: A total of 135 patients were included (mean age 62.3 +/- 13.1 years, 99 males). Glucose tolerance test and HbA1c together diagnosed 18 (13.3%) new cases of diabetes mellitus and 77 (57.0%) patients with pre-diabetes mellitus. Fasting glucose + HbA1c (guidelines strategy) identified 12/18 patients with diabetes mellitus (Sens 66.7%; negative predictive value 95.1%; Kappa 0.78; p < 0.0001) and 83/95 patients with glucose anomalies (pre- diabetes mellitus + diabetes mellitus) (Sens 87.4%; negative predictive value 76.9%). Performing glucose tolerance test in the 29 patients with an elevated FINnish Diabetes RIsk SCore would allow identifying 15/18 patients with diabetes mellitus (Sens 83.3%; negative predictive value 97.5%; Kappa 0.85; p < 0.0001) and 86/95 patients with glucose anomalies (Sens 90.5%; negative predictive value 81.6%). DISCUSSION: Although this strategy improved the screening accuracy, one in each six patients with diabetes mellitus would still remain undiagnosed, as compared to measuring HbA1c and performing an glucose tolerance test in all patients. CONCLUSION: Using the FINnish Diabetes RIsk SCore to select candidates to additional glucose tolerance test improves the accuracy for identifying diabetic patients, as compared with fasting glucose + HbA1c alone. However, 1/6 patients diabetes mellitus is still left undiagnosed with this strategy proposed by the current guidelines.info:eu-repo/semantics/publishedVersio

In vitro and in vivo efficacy of edelfosine-loaded lipid nanoparticles against glioma.

Edelfosine is the prototype molecule of a family of anticancer drugs collectively known as synthetic alkyl-lysophospholipids. This drug holds promise as a selective antitumor agent, and a number of preclinical assays are in progress. In this study, we observe the accumulation of edelfosine in brain tissue after its oral administration in Compritol® and Precirol® lipid nanoparticles (LN). The high accumulation of edelfosine in brain was due to the inhibition of P-glycoprotein by Tween® 80, as verified using a P-glycoprotein drug interaction assay. Moreover, these LN were tested in vitro against the C6 glioma cell line, which was later employed to establish an in vivo xenograft mouse model of glioma. In vitro studies revealed that edelfosine-loaded LN induced an antiproliferative effect in C6 glioma cell line. In addition, in vivo oral administration of drug-loaded LN in NMRI nude mice bearing a C6 glioma xenograft tumor induced a highly significant reduction in tumor growth (p<0.01) fourteen days after the beginning of the treatment. Our results showed that Tween® 80 coated Compritol® and Precirol® LN can effectively inhibit the growth of C6 glioma cells in vitro and suggest that edelfosine-loaded LN represent an attractive option for the enhancement of antitumor activity on brain tumors in vivo