Acute stress regulates vasotocinergic and isotocinergic systems in the gilthead sea bream (Sparus aurata L.).

The hypothalamus-pituitary-interrenal axis is involved in stress response regulation. In addition, arginine vasotocin (AVT) and isotocin (IT) are also considered as important players in this stress regulation. The present study assessed, using the teleost gilthead sea bream (Sparus aurata) as a biological model, hypothalamic mRNA expression changes of AVT and IT and their receptors at hepatic level after an acute stress situation. Specimens were submitted to air for 3 min and place back in their respective tanks after that, being sampled at different times (15 min, 30 min, 1, 2, 4 and 8 hours post-stress) in order to study the time course response. Plasma cortisol values increased after few minutes post-exposure, decreasing during the experimental time while a metabolic reorganization occurred in both plasmatic and hepatic levels. At hypothalamic level, acute stress affects mRNA expression of AVT and IT precursors, as well as hepatic expression of their receptors, suggesting the involvement of both vasotocinergic and isotocinergic systems in the acute stress response. Our results demonstrate the activation and involvement of both endocrine pathways in the regulation of metabolic and stress systems of Sparus aurata, which is stated, at least, through changes in mRNA expression levels of these genes analysed.

Implementazione dell'algoritmo filtered back-projection (FBP) per architetture low-power di tipo systems-on-chip

Il presente lavoro di tesi, svolto presso i laboratori dell'X-ray Imaging Group del Dipartimento di Fisica e Astronomia dell'Università di Bologna e all'interno del progetto della V Commissione Scientifica Nazionale dell'INFN, COSA (Computing on SoC Architectures), ha come obiettivo il porting e l’analisi di un codice di ricostruzione tomografica su architetture GPU installate su System-On-Chip low-power, al fine di sviluppare un metodo portatile, economico e relativamente veloce. Dall'analisi computazionale sono state sviluppate tre diverse versioni del porting in CUDA C: nella prima ci si è limitati a trasporre la parte più onerosa del calcolo sulla scheda grafica, nella seconda si sfrutta la velocità del calcolo matriciale propria del coprocessore (facendo coincidere ogni pixel con una singola unità di calcolo parallelo), mentre la terza è un miglioramento della precedente versione ottimizzata ulteriormente. La terza versione è quella definitiva scelta perché è la più performante sia dal punto di vista del tempo di ricostruzione della singola slice sia a livello di risparmio energetico. Il porting sviluppato è stato confrontato con altre due parallelizzazioni in OpenMP ed MPI. Si è studiato quindi, sia su cluster HPC, sia su cluster SoC low-power (utilizzando in particolare la scheda quad-core Tegra K1), l’efficienza di ogni paradigma in funzione della velocità di calcolo e dell’energia impiegata. La soluzione da noi proposta prevede la combinazione del porting in OpenMP e di quello in CUDA C. Tre core CPU vengono riservati per l'esecuzione del codice in OpenMP, il quarto per gestire la GPU usando il porting in CUDA C. Questa doppia parallelizzazione ha la massima efficienza in funzione della potenza e dell’energia, mentre il cluster HPC ha la massima efficienza in velocità di calcolo. Il metodo proposto quindi permetterebbe di sfruttare quasi completamente le potenzialità della CPU e GPU con un costo molto contenuto. Una possibile ottimizzazione futura potrebbe prevedere la ricostruzione di due slice contemporaneamente sulla GPU, raddoppiando circa la velocità totale e sfruttando al meglio l’hardware. Questo studio ha dato risultati molto soddisfacenti, infatti, è possibile con solo tre schede TK1 eguagliare e forse a superare, in seguito, la potenza di calcolo di un server tradizionale con il vantaggio aggiunto di avere un sistema portatile, a basso consumo e costo. Questa ricerca si va a porre nell’ambito del computing come uno tra i primi studi effettivi su architetture SoC low-power e sul loro impiego in ambito scientifico, con risultati molto promettenti.

Lie algebras and triple systems

This thesis is dedicated to the Tits-Kantor-Koecher (TKK) construction which establishes a bijective correspondence between unital Jordan algebras and shortly graded Lie algebras with Z-grading induced by an sl_2-triple. It is based on the observation that if g is a Lie algebra with a short Z-grading and f lies in g_1, then the formula ab=[[a,f],b] defines a structure of a Jordan algebra on g_{-1}. The TKK construction has been extended to Jordan triple systems and, more recently, to the so-called Kantor triple systems. These generalizations are studied in the thesis.

A New Reactor Concept for Efficient Solar-Thermochemical Fuel Production

We describe and analyze the efficiency of a new solar-thermochemical reactor concept, which employs a moving packed bed of reactive particles produce of H-2 or CO from solar energy and H2O or CO2. The packed bed reactor incorporates several features essential to achieving high efficiency: spatial separation of pressures, temperature, and reaction products in the reactor; solid-solid sensible heat recovery between reaction steps; continuous on-sun operation; and direct solar illumination of the working material. Our efficiency analysis includes material thermodynamics and a detailed accounting of energy losses, and demonstrates that vacuum pumping, made possible by the innovative pressure separation approach in our reactor, has a decisive efficiency advantage over inert gas sweeping. We show that in a fully developed system, using CeO2 as a reactive material, the conversion efficiency of solar energy into H-2 and CO at the design point can exceed 30%. The reactor operational flexibility makes it suitable for a wide range of operating conditions, allowing for high efficiency on an annual average basis. The mixture of H-2 and CO, known as synthesis gas, is not only usable as a fuel but is also a universal starting point for the production of synthetic fuels compatible with the existing energy infrastructure. This would make it possible to replace petroleum derivatives used in transportation in the U. S., by using less than 0.7% of the U. S. land area, a roughly two orders of magnitude improvement over mature biofuel approaches. In addition, the packed bed reactor design is flexible and can be adapted to new, better performing reactive materials.

Potential and limitations of organic and fair trade cotton for improving livelihoods of smallholders: evidence from Central Asia

Cotton is a leading agricultural non-food commodity associated with soil degradation, water pollution and pesticide poisoning due to high levels of agrochemical inputs. Organic farming is often promoted as a means of addressing the economic, environmental and health risks of conventional cotton production, and it is slowly gaining ground in the global cotton market. Organic and fair trade cotton are widely seen as opportunities for smallholder farmers to improve their livelihoods thanks to higher returns, lower input costs and fewer risks. Despite an increasing number of studies comparing the profitability of organic and non-organic farming systems in developing and industrialized countries, little has been published on organic farming in Central Asia. The aim of this article is to describe the economic performance and perceived social and environmental impacts of organic cotton in southern Kyrgyzstan, drawing on a comparative field study conducted by the author in 2009. In addition to economic and environmental aspects, the study investigated farmers’ motivations toward and assessment of conversion to organic farming. Cotton yields on organic farms were found to be 10% lower, while input costs per unit were 42% lower; as a result, organic farmers’ cotton revenues were 20% higher. Due to lower input costs as well as organic and fair trade price premiums, the average gross margin from organic cotton was 27% higher. In addition to direct economic benefits, organic farmers enjoy other benefits, such as easy access to credit on favorable terms, provision of uncontaminated cottonseed cooking oil and cottonseed cake as animal feed, and marketing support as well as extension and training services provided by newly established organic service providers. The majority of organic farmers perceive improved soil quality, improved health conditions, and positively assess their initial decision to convert to organic farming. The major disadvantage of organic farming is the high manual labor input required. In the study area, where manual farm work is mainly women's work and male labor migration is widespread, women are most affected by this negative aspect of organic farming. Altogether, the results suggest that, despite the inconvenience of a higher workload, the advantages of organic farming outweigh its disadvantages and that conversion to organic farming improves the livelihoods of small-scale farmers.

Developmental changes of BOLD signal correlations with global human EEG power and synchronization during working memory

In humans, theta band (5-7 Hz) power typically increases when performing cognitively demanding working memory (WM) tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent) signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and higher frequency band synchronization is modulated during WM. Yet, little is known about the link between BOLD, EEG power, and EEG synchronization during WM, and how these measures develop with human brain maturation or relate to behavioral changes. We examined EEG-BOLD signal correlations from 18 young adults and 15 school-aged children for age-dependent effects during a load-modulated Sternberg WM task. Frontal load (in-)dependent EEG theta power was significantly enhanced in children compared to adults, while adults showed stronger fMRI load effects. Children demonstrated a stronger negative correlation between global theta power and the BOLD signal in the default mode network relative to adults. Therefore, we conclude that theta power mediates the suppression of a task-irrelevant network. We further conclude that children suppress this network even more than adults, probably from an increased level of task-preparedness to compensate for not fully mature cognitive functions, reflected in lower response accuracy and increased reaction time. In contrast to power, correlations between instantaneous theta global field synchronization and the BOLD signal were exclusively positive in both age groups but only significant in adults in the frontal-parietal and posterior cingulate cortices. Furthermore, theta synchronization was weaker in children and was--in contrast to EEG power--positively correlated with response accuracy in both age groups. In summary we conclude that theta EEG-BOLD signal correlations differ between spectral power and synchronization and that these opposite correlations with different distributions undergo similar and significant neuronal developments with brain maturation.

Power and Robustness of Linkage Tests for Quantitative Traits in General Pedigrees

There are numerous statistical methods for quantitative trait linkage analysis in human studies. An ideal such method would have high power to detect genetic loci contributing to the trait, would be robust to non-normality in the phenotype distribution, would be appropriate for general pedigrees, would allow the incorporation of environmental covariates, and would be appropriate in the presence of selective sampling. We recently described a general framework for quantitative trait linkage analysis, based on generalized estimating equations, for which many current methods are special cases. This procedure is appropriate for general pedigrees and easily accommodates environmental covariates. In this paper, we use computer simulations to investigate the power robustness of a variety of linkage test statistics built upon our general framework. We also propose two novel test statistics that take account of higher moments of the phenotype distribution, in order to accommodate non-normality. These new linkage tests are shown to have high power and to be robust to non-normality. While we have not yet examined the performance of our procedures in the context of selective sampling via computer simulations, the proposed tests satisfy all of the other qualities of an ideal quantitative trait linkage analysis method.

Clinical evaluation of root filled teeth restored with or without post-and-core systems in a specialist practice setting

AIM: To assess survival rates and complications of root-filled teeth restored with or without post-and-core systems over a mean observation period of >or=4 years. METHODOLOGY: A total of 325 single- and multirooted teeth in 183 subjects treated in a private practice were root filled and restored with either a cast post-and-core or with a prefabricated titanium post and composite core. Root-filled teeth without post-retained restorations served as controls. The restored teeth served as abutments for single unit metal-ceramic or composite crowns or fixed bridges. Teeth supporting cantilever bridges, overdentures or telescopic crowns were excluded. RESULTS: Seventeen teeth in 17 subjects were lost to follow-up (17/325: 5.2%). The mean observation period was 5.2 +/- 1.8 (SD) years for restorations with titanium posts, 6.2 +/- 2.0 (SD) years for cast post-and-cores and 4.4 +/- 1.7 (SD) years for teeth without posts. Overall, 54% of build-ups included the incorporation of a titanium post and 26.5% the cementation of a cast post-and-core. The remaining 19.5% of the teeth were restored without intraradicular retention. The adjusted 5-year tooth survival rate amounted to 92.5% for teeth restored with titanium posts, to 97.1% for teeth restored with cast post-and-cores and to 94.3% for teeth without post restorations, respectively. The most frequent complications included root fracture (6.2%), recurrent caries (1.9%), post-treatment periradicular disease (1.6%) and loss of retention (1.3%). CONCLUSION: Provided that high-quality root canal treatment and restorative protocols are implemented, high survival and low complication rates of single- and multirooted root-filled teeth used as abutments for fixed restorations can be expected after a mean observation period of >or=4 years.