Conduction mechanisms in p-type Pb1-xEuxTe alloys in the insulator regime

Electrical resistivity measurements were performed on p-type Pb1-xEuxTe films with Eu content x = 4%, 5%, 6%, 8%, and 9%. The well-known metal-insulator transition that occurs around 5% at room temperature due to the introduction of Eu is observed, and we used the differential activation energy method to study the conduction mechanisms present in these samples. In the insulator regime (x>6%), we found that band conduction is the dominating conduction mechanism for high temperatures with carriers excitation between the valence band and the 4f levels originated from the Eu atoms. We also verified that mix conduction dominates the low temperatures region. Samples with x = 4% and 5% present a temperature dependent metal insulator transition and we found that this dependence can be related to the relation between the thermal energy k(B)T and the activation energy Delta epsilon(a). The physical description obtained through the activation energy analysis gives a new insight about the conduction mechanisms in insulating p-type Pb1-xEuxTe films and also shed some light over the influence of the 4f levels on the transport process in the insulator region. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729813]

Recoupled separated-local-field experiments and applications to study intermediate-regime molecular motions

A specific separated-local-field NMR experiment, dubbed Dipolar-Chemical-Shift Correlation (DIPSHIFT) is frequently used to study molecular motions by probing reorientations through the changes in XH dipolar coupling and T-2. In systems where the coupling is weak or the reorientation angle is small, a recoupled variant of the DIPSHIFT experiment is applied, where the effective dipolar coupling is amplified by a REDOR-like pi-pulse train. However, a previously described constant-time variant of this experiment is not sensitive to the motion-induced T-2 effect, which precludes the observation of motions over a large range of rates ranging from hundreds of Hz to around a MHz. We present a DIPSHIFT implementation which amplifies the dipolar couplings and is still sensitive to T-2 effects. Spin dynamics simulations, analytical calculations and experiments demonstrate the sensitivity of the technique to molecular motions, and suggest the best experimental conditions to avoid imperfections. Furthermore, an in-depth theoretical analysis of the interplay of REDOR-like recoupling and proton decoupling based on Average-Hamiltonian Theory was performed, which allowed explaining the origin of many artifacts found in literature data. (C) 2012 Elsevier Inc. All rights reserved.

Interação genótipo x local x regime alimentar em bovinos nelore por meio de componentes principais de três modos

O principal objetivo deste estudo foi aplicar componentes principais com múltiplas matrizes de dados para verificar a interação tripla genótipo x local x regime alimentar no valor genético do efeito direto do peso, aos 205 dias de idade. Foram utilizados touros com filhos em três regiões de produção do Nordeste Brasileiro (Maranhão, Mata e Agreste, e Recôncavo Baiano) e criados nos regimes alimentares a pasto ou com suplementação. Não se evidenciou interação genótipo x local para a característica estudada, entretanto, constatou-se interação do genótipo x regime alimentar. A utilização dos touros deve ser direcionada de acordo com o regime alimentar de seus filhos.

O regime de metas de inflação no Brasil: uma análise empírica do IPCA

O regime monetário de metas de inflação é um padrão de conduta da política monetária que passou a ser utilizado por vários países a partir da década de 1990, dentre eles o Brasil, que adotou este modelo em 1999, após uma crise cambial. Com seu arcabouço teórico pautado nas premissas da teoria novo-clássica e tendo como principal característica o anúncio prévio de uma meta numérica para a inflação, este regime passou a ser adotado por países que buscavam alcançar a estabilidade de seus preços. O presente trabalho irá brevemente expor a base teórica e as características do referido regime. Porém, o foco principal será a discussão da utilização do IPCA (Índice de Preços ao Consumidor Amplo) pelo regime de metas como balizador da inflação no Brasil.

Necrosis response to photodynamic therapy using light pulses in the femtosecond regime

One of the clinical limitations of the photodynamic therapy (PDT) is the reduced light penetration into biological tissues. Pulsed lasers may present advantages concerning photodynamic response when compared to continuous wave (CW) lasers operating under the same average power conditions. The aim of this study was to investigate PDT-induced response when using femtosecond laser (FSL) and a first-generation photosensitizer (Photogem) to evaluate the induced depth of necrosis. The in vitro photodegradation of the sensitizer was monitored during illumination either with CWor an FSL as an indirect measurement of the PDT response. Healthy liver of Wistar rats was used to evaluate the tissue response. The photosensitizer was endovenously injected and 30 min after, an energy dose of 150 Jcm-2 was delivered to the liver surface. We observed that the photodegradation rate evaluated via fluorescence spectroscopy was higher for the FSL illumination. The FSL-PDT produced a necrosis nearly twice as deep when compared to the CW-PDT. An increase of the tissue temperature during the application was measured and was not higher than 2.5 °C for the CW laser and not higher than 4.5 °C for the pulsed laser. FSL should be considered as an alternative in PDT applications for improving the results in the treatment of bulky tumors where higher light penetration is required.

Human Abuses of Coral Reefs- Adaptive Responses and Regime Transitions

During the last few decades, coral reefs have become a disappearing feature of tropical marine environments, and those reefs that do remain are severely threatened. It is understood that humans have greately altered the environment under which these ecosystems previously have thrived and evoloved. Overharvesting of fish stocks, global warming and pollution are some of the most prominent threats, acting on coral reefs at several spatial and temporal scales. Presently, it is common that coral reefs have been degraded into alternative ecosystem regimes, such as macroalgae-dominated or sea urchin-barren. Although these ecosystems could potentially return to coral dominance in a long-term perspective, when considdering current conditions, it seems likely that they will persist in their degraded states. Thus, recovery of coral reefs cannot be taken for granted on a human timescale. Multiple stressors and disturbances, which are increasingly characteristic of coral reef environments today, are believed to act synergistically and produce ecological surprises. However, current knowledge of effects of compounded disturbances and stress is limited. Based on five papers, this thesis investigates the sublethal response of multiple stressors on coral physiology, as well as the effects of compounded stress and disturbance on coral reef structure and function. Adaptive responses to stress and disturbance in relation to prior experience are highlighted. The thesis further explores how inherent characteristics (traits) of corals and macroalgae may influence regime expression when faced with altered disturbance regimes, in particular overfishing, eutrophication, elevated temperature, and enhanced substrate availability. Finally, possibilities of affecting the resilience of macroalgae-dominaed reefs and shifting the community composition towards a coral-dominated regime are explored.

Local flow under weak trade wind regime

[EN] On 8-10 April 2007, several episodes of intense sea-breeze fronts were registered at the islands of Fuerteventura and Lanzarote (Canary Islands). The sea-breeze circulation was primary driven by daytime heating contrasts between land and the Atlantic Ocean during a period of weak trade winds. Numerical simulations of these events were carried out using the 3.1.1 version of the Weather Research and Forecasting (WRF-ARW) Model. Three different domains with 6.6-km, 2.2-km and 0.7-km horizontal grid spacing and two sets with 51 and 70 vertical sigma levels were defined. The simulation was performed using two-way interactive nesting between the first and the second domain, using different land surface model parameterizations (Thermal diffusion, Noah LSM and RUC) for comparison. Initial conditions were provided by the NCAR Dataset analysis from April 2007, which were improved using surface and upper-air observations. The poster is focused on the 10 April episode.

Colonization of gastropods on subtidal reefs depends on density in adjacent habitats, not on disturbance regime

[EN] Habitats dominated by algal canopies are often altered by physical disturbances of varying severity, changing environmental conditions and biological processes. We used Artificial Seaweed Units (ASUs) to test whether severity of physical disturbances on algal canopies affects the post-disturbance colonization of gastropods on subtidal reefs. Specifically, we examined patterns of assemblage structure of gastropods to test the hypothesis that the extent and intensity of canopy removal affects the post-disturbance colonization of ASUs, testing the consistency of these effects among four regions encompassing a 68 latitudinal gradient in southwestern Australia. Because adjacent habitats can act as a source of new colonists (either as drifting migrants or as a source of propagules) from the perimeter surrounding perturbed areas, we also predicted that patterns of colonization (types and total abundances of colonizers) were influenced by the available pool of individuals at the scale of reefs. Three reefs were selected within each region. On each reef, ASUs were placed in the centre of circular canopy clearings of different size (0, 3, 13 and 50 m2) and intensity (50% vs 100%), and retrieved after 3 months. Resulting assemblages occupying the ASUs were quantitatively representative of the adjacent (undisturbed), algal-associated, assemblages at the scale of reef. Within reefs, recruited assemblages largely mimicked those associated with erect red algae. However, neither disturbance size nor intensity affected the colonization patterns across reefs and regions. These results suggest that algal-associated gastropods, regardless of the prevalent mode of dispersion, are resilient to physical disturbances to canopies across broad geographical regions as long as the pool of potential colonists is maintained. A high dispersal ability of gastropods likely ensures a quick colonization of recovering algal habitats.

I giudici del CSM. Il regime giuridico degli atti del CSM sullo status dei magistrati

L’elaborato è dedicato all’esame della forma di emanazione e del sistema d’impugnazione degli atti del CSM circa la carriera giuridica dei magistrati, con particolare attenzione alle numerose implicazioni di livello costituzionale ed amministrativo sollevate dalla problematica. I principali obiettivi perseguiti sono: a) la verifica della costituzionalità del sistema predisposto dalla legge 24 marzo 1958, n. 195, la quale stabilisce che i provvedimenti consiliari siano emanati con decreto presidenziale o ministeriale e che possano essere sindacati dai giudici amministrativi; b) l’individuazione e la risoluzione delle ambiguità interpretative e dei dubbi applicativi che sono emersi fin dall’introduzione della legge in parola e che tutt’ora continuano costantemente a riproporsi, non avendo trovato compiuta sistemazione né in dottrina né in giurisprudenza; c) la ricognizione e l’esame critico della prassi giurisprudenziale, specialmente in ordine alle decisioni più recenti, tenuto conto della mancanza di studi aggiornati in merito pur a fronte dell’ampio numero di pronunce. Sulla base dell’ipotesi di partenza dell’irrinunciabilità, per la piena comprensione della portata precettiva della legge sopra citata, di un’esaustiva analisi delle premesse teoriche necessarie per una piena comprensione dello stessa, lo svolgimento è sostanzialmente articolato in due parti fondamentali. La prima incentrata sulla ricostruzione del perimetro costituzionale dell’indagine, con specifico riferimento all’assetto costituzionale della Magistratura. La seconda, riconducibile nell’alveo proprio del “diritto amministrativo”, concernente a) il significato e la funzione da attribuire alla forma di emanazione degli atti consiliari; b) i poteri ministeriali e presidenziali nella fase di esternazione; c) la tipologia degli atti impugnabili e dei vizi sindacabili in sede giurisdizionale. Con la consapevolezza che lo sviluppo dell’argomento prescelto rappresenta un’angolazione di visuale privilegiata relativamente allo svolgersi dei rapporti tra Potere Esecutivo ed Ordine giudiziario, la tesi affronta complesse questioni di carattere generale quali il principio di separazione dei poteri, il concetto di organo costituzionale e quello di autodichìa, la nozione di autonomia pubblica, i princìpi di imparzialità ed uguaglianza. Il vaglio della giurisprudenza costituzionale ed amministrativa, ampiamente richiamata, è condotto trattando a fondo, sia aspetti connotati da un elevato tasso di tecnicità, come la disciplina del conferimento d’incarichi direttivi, sia interrogativi concernenti diversi aspetti problematici. Segnatamente, l’indagine ha riguardato – tra l’altro – l’ammissibilità del sindacato del giudice amministrativo sugli atti “amministrativi” delle autorità non incardinate nella P.A.; la compatibilità dell’interpretazione evolutiva con l’art. 138 Cost.; la definizione di atto amministrativo; la stessa nozione costituzionale di pubblica amministrazione. La presa d’atto della tendenza giurisprudenziale ad estendere il sindacato al vizio di eccesso di potere conduce infine ad alcune riflessioni conclusive in merito alla conciliabilità del ruolo assunto dal giudice amministrativo col quadro normativo delineato dai Costituenti.

Analisi delle prestazioni energetiche in regime estivo di un impianto di climatizzazione ad uso terziario

Questo lavoro di tesi si propone di verificare la validità della nuova specifica tecnica UNI/TS 11300-Parte 3, riguardante i consumi energetici degli edifici nella stagione estiva. Pertanto tale specifica tecnica, ancora in fase d’inchiesta pubblica, è stata applicata ad un caso reale, quale un complesso di edifici ad uso terziario, con il duplice obiettivo di analizzarne lo specifico metodo di calcolo e di comprovarne l’efficacia. Nel corso dello studio, prendendo in esame nella parte introduttiva argomenti quali i consumi in edilizia, gli aspetti normativi e le modalità di produzione del freddo, si è giunti infine a calcolare il fabbisogno di energia primaria per il raffrescamento del complesso di riferimento, e nella parte conclusiva sono state fornite indicazioni su eventuali modifiche da apportare alla normativa per ridurre i consumi.

Regime giuridico del farmaco negli ordinamenti italiano e spagnolo: la trasposizione del diritto farmaceutico europeo

Nel presente lavoro di ricerca analizziamo, da una prospettiva tanto giuridica quanto metagiuridica (e, senz’ombra di dubbio, decisamente europeista), il regime giuridico-amministrativo dei farmaci di uso umano nella cui fabbricazione interviene un processo industriale e le nuove vicissitudini a cui il suddetto regime deve far fronte all’interno della cosiddetta società del rischio e dell’innovazione. In particolare, vogliamo fare luce sul regime giuridico del farmaco negli ordinamenti italiano e spagnolo, come trasposizione del Diritto farmaceutico europeo.