Scheduling of a hydro producer considering head-dependency, price scenarios and risk-aversion

In this paper, a mixed-integer quadratic programming approach is proposed for the short-term hydro scheduling problem, considering head-dependency, discontinuous operating regions and discharge ramping constraints. As new contributions to earlier studies, market uncertainty is introduced in the model via price scenarios, and risk aversion is also incorporated by limiting the volatility of the expected profit through the conditional value-at-risk. Our approach has been applied successfully to solve a case Study based on one of the main Portuguese cascaded hydro systems, requiring a negligible computational time.

Digitally programmable delay-locked-loop with adaptive charge pump current for UWB radar system

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e Computadores

Stochastic Framework for Strategic Decision-making of Load-serving Entities for Day-ahead Market

The deregulation of electricity markets has diversified the range of financial transaction modes between independent system operator (ISO), generation companies (GENCO) and load-serving entities (LSE) as the main interacting players of a day-ahead market (DAM). LSEs sell electricity to end-users and retail customers. The LSE that owns distributed generation (DG) or energy storage units can supply part of its serving loads when the nodal price of electricity rises. This opportunity stimulates them to have storage or generation facilities at the buses with higher locational marginal prices (LMP). The short-term advantage of this model is reducing the risk of financial losses for LSEs in DAMs and its long-term benefit for the LSEs and the whole system is market power mitigation by virtually increasing the price elasticity of demand. This model also enables the LSEs to manage the financial risks with a stochastic programming framework.

Resistencia a la enfermedad de cría yesificada por colonias de Apis mellifera con eficiente comportamiento higiénico (Hymenoptera, Apidae)

In an apiary composed of 14 hygienic and 7 non-hygienic colonies of Apis mellifera Linnaeus, 1758 the presence of visible and capped mummies was recorded, one hygienic and 4 non-hygienic colonies showed symptoms of chalkbrood. Twenty-eight days after a massive contamination of the colonies with pollen patties containing Ascosphaera apis Olive & Spiltoir, 1955, the situation was almost identical to that at the beginning: the same 4 non-hygienic colonies still were infected and one hygienic colony that was healthy became infected. The high proportion of hygienic colonies that eliminated the disease symptoms suggests that they could maintain themselves healthy in spite of the presence of colonies with chalkbrood in the apiary.

Optimització d'un dispositiu de compactació de pols metàl·lica en calent

El projecte tracta de l’optimització d’un dispositiu de compactació de pols metàl•lica en calent que s’acobla a la màquina d’assaigs mecànics MTS (Material Testing Systems) model 858 i al forn integrat a aquesta. El dispositiu té la funció de compactar la pols metàl•lica amb la força axial de compressió de la MTS, mentre que alhora s’aplica calor del forn integrat. El resultat d’aquest procediment és l’obtenció de mostres compactades i densificades.

Disseny del servidor de control d'un sistema de vídeo sota demanda

El treball realitzat dóna una visió global sobre els sistemes de vídeo sota demanda i la problemàtica associada al seu desenvolupament. Es mostra quines solucions s'han adoptat per abordar aquesta problemàtica a l'hora de dissenyar un sistema de VoD i, en particular, el treball se centra en l'anàlisi i desenvolupament del corresponent servidor de control.

Trypanosoma cruzi: metacyclogenesis in vitro - I. Changes in the properties of metacyclic trypomastigotes maintained in the laboratory by different methods

In this work we have studied the modifications in the biological properties of Trypanosoma cruzi when the parasite is maintained for a long time in axenic culture. The studies were done with a clone from an avirulent strain (Dm30L) and a non-cloned virulent strain (EP) of T. cruzi. Both parasiteswere maintained, for at least three years, by successive triatomine/mouse alternate passage (control condition), or by serial passage in axenic medium (culture condition), or only in the mouse (mouse condition). The comparison between parasites of culture and control condition showed that metacyclogenesis capacity was reduced in the former and that the resulting metacyclics displayed an attenuatedvirulence. In order to compare the virulence of metacyclics from the urine of the insect vector, Rhodnius prolixus were infected by artificial feeding with parasites of the control or culture condition. After three triatomine/triatomine passages, there was observed an almost identical biological behavior for these parasites, hence indicating that the maintenance of T. cruzi for a long time in axenic culture affects the differentiation capacity and the virulence of the parasite. Additionally, it was demonstrated that it is possible to maintain T. cruzi exclusively through passages in the invertebrate host.

Three-dimensional models of 14α-sterol demethylase (Cyp51A) from Aspergillus lentulus and Aspergillus fumigatus: an insight into differences in voriconazole interaction.

Aspergillus lentulus, an Aspergillus fumigatus sibling species, is increasingly reported in corticosteroid-treated patients. Its clinical significance is unknown, but the fact that A. lentulus shows reduced antifungal susceptibility, mainly to voriconazole, is of serious concern. Heterologous expression of cyp51A from A. fumigatus and A. lentulus was performed in Saccharomyces cerevisiae to assess differences in the interaction of Cyp51A with the azole drugs. The absence of endogenous ERG11 was efficiently complemented in S. cerevisiae by the expression of either Aspergillus cyp51A allele. There was a marked difference between azole minimum inhibitory concentration (MIC) values of the clones expressing each Aspergillus spp. cyp51A. Saccharomyces cerevisiae clones expressing A. lentulus alleles showed higher MICs to all of the azoles tested, supporting the hypothesis that the intrinsic azole resistance of A. lentulus could be associated with Cyp51A. Homology models of A. fumigatus and A. lentulus Cyp51A protein based on the crystal structure of Cyp51p from Mycobacterium tuberculosis in complex with fluconazole were almost identical owing to their mutual high sequence identity. Molecular dynamics (MD) was applied to both three-dimensional protein models to refine the homology modelling and to explore possible differences in the Cyp51A-voriconazole interaction. After 20ns of MD modelling, some critical differences were observed in the putative closed form adopted by the protein upon voriconazole binding. A closer study of the A. fumigatus and A. lentulus voriconazole putative binding site in Cyp51A suggested that some major differences in the protein's BC loop could differentially affect the lock-up of voriconazole, which in turn could correlate with their different azole susceptibility profiles.

Strategies of use of a specific immunoglobulin-rich egg yolk powder in weaning piglets

Two experiments were performed to determine the best strategy of use of the product TRACTcare® 4P (ITPSA) (TC, specific immunoglobulin-rich egg yolk powder within an energetic fatty acid matrix) in piglets from weaning and for 6 weeks, in diets without or with inclusion of antibiotics. Each trial was performed with 144 piglets in 24 pens, in a completely randomized design blocked by initial body weight. Feeds were formulated according to animal requirements in two periods. In the first trial no antibiotics were included in the feeds and no room disinfection from previous trial was performed; treatments were: 1) Negative control (NC); 2) NC+TC on top of the feed within the hopper for the first 3 days on trial (30 g/pig×day), and eventually if diarrhea appeared (TCOT); 3) NC+TC ad libitum provided in an extra hopper within the pen (TCAL); and 4) NC+TC at 5 g/kg added to the feed in the mixer (TC5). In the second trial, treatments were: 1) Positive control: basal diet that included 250 mg/kg amoxiciline (BD)+100 mg/kg colistine (AC); 2) BD+2 g/kg TC (TC2A); 3) BD+5 g/kg TC (TC5A); and 4) BD+8 g/kg TC (TC8A). In diets without antibiotics, the product TC at 5 g/kg in the feed numerically improved BW by 8% compared to Control animals, while G:F was almost identical between both groups. When antibiotics were used in the feed, replacement of colistin at 100 mg/kg for TC at 2 g/kg in feed numerically improved the performance compared to Positive control animals (for the whole trial period ADG 8% better: 390 g vs. 361 g; G:F 1% better: 0.748 kg/kg vs. 0.742 kg/kg), possibly due to the stimulation of feed consumption at weaning. In both trials, the lower number of dead and culled animals from TC5 and TC2A together with higher BW represented an advantage over Control treatments of 6% to 10% animals more and 15% to 17% total BW more at the end of the trial.

Oxidative and nonoxidative glucose metabolism following graded doses of oral glucose in man.

The oxidative and nonoxidative glucose metabolism represent the two major mechanisms of the utilization of a glucose load. Eight normal subjects were administered oral loads of 50, 100 and 150 g glucose and gas exchange measurements were performed for eight hours by means of computerized continuous indirect calorimetry. The glycemic peaks were almost identical with all three doses with a rise to between 141 and 147 mg/dl at 60 min. The fall back to basal level was reached later with the high than with the low glucose doses. The glucose oxidation rate rose to values between 223 and 253 mg/min after the three glucose doses, but while falling immediately after the peak at 120 min following the 50 g load, the glucose oxidation rate remained at its maximum rate until 210 min for the 100 g glucose load and plateaued up to 270 min for the 150 g glucose dose. The oxidation rates then fell gradually to reach basal levels at 270, 330 and 420 min according to the increasing size of the load. Altogether 55 +/- 3 g glucose were oxidized during the 8 hours following the 50 g glucose load, 75 +/- 3 g after the 100 g load and 80 +/- 5 g after the 150 g load. The nonoxidative glucose disposal, which corresponds essentially to glucose storage, varied according to the size of the glucose load, with uptakes of 20 +/- 1, 60 +/- 1 and 110 +/- 1 g glucose 180 min after the 50, 100 and 150 g glucose loads respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Mètodes algebraics i de teoria de la prova per a la formalització del raonament vague

Projecte de recerca elaborat a partir d’una estada a la Università degli studi di Siena, Italy , entre 2007 i 2009. El projecte ha consistit en un estudi de la formalització lògica del raonament en presència de vaguetat amb els mètodes de la Lògica Algebraica i de la Teoria de la Prova. S'ha treballat fonamental en quatre direccions complementàries. En primer lloc, s'ha proposat un nou plantejament, més abstracte que el paradigma dominant fins ara, per l'estudi dels sistemes de lògica borrosa. Fins ara en l'estudi d'aquests sistemes l'atenció havia recaigut essencialment en l'obtenció de semàntiques basades en tnormes contínues (o almenys contínues per l'esquerra). En primer nivell de major abstracció hem estudiat les propietats de completesa de les lògiques borroses (tant proposicionals com de primer ordre) respecte de semàntiques definides sobre qualsevol cadena de valors de veritat, no necessàriament només sobre l'interval unitat dels nombres reals. A continuació, en un nivell encara més abstracte, s’ha pres l'anomenada jerarquia de Leibniz de la Lògica Algebraica Abstracta que classifica tots els sistemes lògics amb un bon comportament algebraic i s'ha expandit a una nova jerarquia (que anomenem implicacional) que permet definir noves classes de lògiques borroses que contenen quasi totes les conegudes fins ara. En segon lloc, s’ha continuat una línia d'investigació iniciada els darrers anys consistent en l'estudi de la veritat parcial com a noció sintàctica (és a dir, com a constants de veritat explícites en els sistemes de prova de les lògiques borroses). Per primer cop, s’ha considerat la semàntica racional per les lògiques proposicionals i la semàntica real i racional per les lògiques de primer ordre expandides amb constants. En tercer lloc, s’ha tractat el problema més fonamental del significat i la utilitat de les lògiques borroses com a modelitzadores de (part de) els fenòmens de la vaguetat en un darrer article de caràcter més filosòfic i divulgatiu, i en un altre més tècnic en què defensem la necessitat i presentem l'estat de l'art de l'estudi de les estructures algèbriques associades a les lògiques borroses. Finalment, s’ha dedicat la darrera part del projecte a l'estudi de la complexitat aritmètica de les lògiques borroses de primer ordre.

Hyperthermia and maximal oxygen uptake in men and women.

To compare the effect of hyperthermia on maximal oxygen uptake (VO2max) in men and women, VO2max was measured in 11 male and 11 female runners under seven conditions involving various ambient temperatures (Ta at 50% RH) and preheating designed to manipulate the esophageal (Tes) and mean skin (Tsk) temperatures at VO2max. The conditions were: 25 degrees C, no preheating (control); 25, 35, 40, and 45 degrees C, with exercise-induced preheating by a 20-min walk at approximately 33% of control VO2max; 45 degrees C, no preheating; and 45 degrees C, with passive preheating during which Tes and Tsk were increased to the same degree as at the end of the 20-min walk at 45 degrees C. Compared to VO2max (l x min(-1)) in the control condition (4.52+/-0.46 in men, 3.01+/-0.45 in women), VO2max in men and women was reduced with exercise-induced or passive preheating and increased Ta, approximately 4% at 35 degrees C, approximately 9% at 40 degrees C and approximately 18% at 45 degrees C. Percentage reductions (7-36%) in physical performance (treadmill test time to exhaustion) were strongly related to reductions in VO2max (r=0.82-0.84). The effects of hyperthermia on VO2max and physical performance in men and women were almost identical. We conclude that men and women do not differ in their thermal responses to maximal exercise, or in the relationship of hyperthermia to reductions in VO2max and physical performance at high temperature. Data are reported as mean (SD) unless otherwise stated.

Pliensbachian magnetostratigraphy: new data from Paris Basin (France)

Sampling of an industrial drill string from the northeastern Paris Basin (Montcornet, France) provides early Jurassic magnetostratigraphic data coupled with biochronological control. About 375 paleomagnetic samples were obtained from a 145 m thick series of Pliensbachian rocks. A composite demagnetization thermal up to 300 C and an alternating field up to 80 mT were used to separate the magnetic components. A low unblocking temperature component (<250degreesC) with an inclination of about 64 is interpreted as a present-day field overprint. The characteristic remanent component with both normal and reversed antipodal directions was isolated between 5 and 50 mT. Twenty-nine polarity intervals were recognized. Correlation of these new results from the Paris Basin with data from the Breggia Gorge section (Ticino, southern Alps, Switzerland), which is generally considered as the reference section for Pliensbachian magnetostratigraphy, reveals almost identical patterns of magnetic polarity reversals. However, the correlation implies significant paleontological age discrepancies. Revised age assignments of biostratigraphic data of Breggia as well as an objective evaluation of the uncertainties on zonal boundaries in both Breggia and Moncornet resolve the initial discrepancies between magnetostratigraphic correlations and biostratigraphic ages. Hence, the sequence of magnetic reversals is significantly strengthened and the age calibration is notably improved for the Pliensbachian, a stage for which sections combining adequate magnetic signal and biostratigraphic constraints are still very few. (C) 2002 Elsevier Science B.V. All rights reserved.

Selective suppression of cytokine secretion in whole blood cell cultures of patients with colorectal cancer.

We have investigated the secretion of interferon alpha (IFN-alpha), IFN-gamma, interleukin-1alpha (IL-1alpha), IL-1beta, IL-2 and tumour necrosis factor alpha (TNF-alpha) in whole blood cell cultures (WBCCs) of colorectal cancer patients upon mitogen stimulation. Whereas the values for IL-1beta and TNF-alpha remained virtually unchanged in comparison with healthy control subjects, WBCCs of colorectal cancer patients secreted significantly lower amounts of IFN-alpha (P < 0.005), IFN-gamma (P < 0.0001), IL-1alpha (P < 0.0001) and IL-2 (P < 0.05). This reduction correlated with the progression of the disease. The total leucocyte and monocyte population were almost identical in both groups. In contrast, a dramatic depletion of lymphocytes was observed in colorectal cancer patients, which affected both lymphocyte counts (P < 0.0005) and their distribution (P < 0.0001). Our results suggest a selective suppression of cytokines in colorectal cancer patients that is related to tumour burden. Several mechanisms might account for this phenomenon, one of which might be lymphocyte depletion.

Nature versus nurture in social insect caste determination

Recent evidence for genetic effects on royal and worker caste differentiation from diverse social insect taxa has put an end to the view that these phenotypes stem solely from a developmental switch controlled by environmental factors. Instead, the relative influences of genotypic and environmental effects on caste vary among species, ranging from largely environmentally controlled phenotypes to almost purely genetic systems. Disentangling the selective forces that generate variation for caste predisposition will require characterizing the genetic mechanisms underlying this variation, and identifying particular life-history strategies and kin structures associated with strong genetic effects on caste.