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Modeling solar radiation and wind speed time series for renewable energy applications
No full textThe problem of predicting weather variables, such as solar radiation and wind speed, is of great interest for integrating renewable energies plants, into the electric grid. Indeed, since renewable energy sources are intermittent in nature, predicting future values is important to allow the grid to dispatching generators, in order to satisfy the demand. There are essentially two ways to address the issue of weather variables prediction. One is by using Numerical Weather Forecasting (NWF) models, which are reliable, but also quite complex and requires real time information, usually available from Meteorological Agencies only. Furthermore, very powerful computers are required to solve the differential equations involved. The other kinds of methods are represented by the so-called statistical modeling approaches, which are based on the use of past data recorded at the site of interest. These latter kinds of methods, compared to the former ones, require less computational efforts, but are appropriate only for short time horizons. This PhD Thesis was devoted to study short-term prediction models for solar radiation and wind speed time series and assessing their performance in the range [1, 24] hours. It was also studied the predictability of the daily average values, which for obvious reasons, is much more difficult than that of predicting the hourly averages. To mitigate, as far as possible, the difficulties, the prediction was reformulated in terms of a classification problem. In such a way, instead of predicting 1-day ahead the average value, the target was to predict the class. In this framework, of course, the prediction is as far difficult as large is the number of considered classes. Thus accuracy of 1-day ahead prediction models of the wind speed class was studied, for various frameworks
A study of the super-abundant Bemisia tabaci (Gennadius) species complex (Hemiptera: Aleyrodidae) in cassava mosaic disease pandemic areas in Tanzania
No full textBemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex comprising morphologically indistinguishable but genetically variable populations. It is the vector of cassava mosaic geminiviruses (CMGs) causing cassava mosaic (CMD) disease to cassava (Manihot esculenta Crantz). After the outbreak and spread of a severe CMD from Uganda to several East and Central African countries, the production of cassava has been impaired. The severe CMD pandemic is mainly characterized by high disease severity and super-abundant populations of B. tabaci. This research sought to study the super-abundant populations in Tanzania. The main objectives were to assess the genetic diversity and distribution of cassava-associated B. tabaci, to assess the endosymbiont fauna, and to investigate the population structure of B. tabaci populations found in Tanzania. Hence, whiteflies collected through several field surveys were analysed using mitochondrial and nuclear markers.
The four B. tabaci putative species found to be present in the study area based on mitochondrial data were sub-Saharan Africa 1 (SSA1), Mediterranean (MED), Indian Ocean (IO) and East Africa 1 (EA1). There were four sub-groups (SG) under SSA1 which included SSA1-SG1, SSA1-SG2, SSA1-SG1-2 and SSA1-SG3.
SSA1-SG1 was found to be the pandemic-associated B. tabaci in Tanzania, being found predominantly in the pandemic affected north-western part of the country. The SSA1-SG2 was shown to be present in the pandemic-unaffected central part while SSA1-SG3 was exclusively found confined to the coastal parts.
Microsatellite data also identified SSA1, MED and IO B. tabaci putative species as well as B. afer. It further revealed two sub-clusters within SSA1, which were each dominating different geographic areas across the sampling zones. One type predominated in the north-western pandemic affected part of Tanzania but diminishing in frequency towards the south-east, whilst the other became increasingly common until it becomes almost the only type present in the coastal area. The central part was a mix of the two sub-clusters.
The CMD pandemic front was estimated to lie in Geita Region located in north-western Tanzania and to be spreading from the north-west to the south-east at ca 26 km per year.
The different sub-groups and putative species in the study area exhibited contrasting endosymbionts profiles. Although no particular endosymbiont was found to be associated only with the pandemic-associated SSA1-SG1, the most remarkable feature was the absence of secondary symbiont infection for more than a third of the population. Multiple infection was very common in the remaining SSA1 sub-groups as well as in MED, IO and EA1 putative species.
Finally, the extended presence of the pandemic-associated SSA1-SG1 in areas of up to 180 km to the south-east of the pandemic front is not entirely surprising, as changes in whitefly populations precede changes in disease status. However, the advancement of this pandemic-associated sub-group further into the non-pandemic central part coupled with the possibilities of gene flow and hybridization observed with other sub-groups poses an on-going threat to cassava production in the region.
Therefore, future studies should focus towards understanding the exact nature of secondary symbionts on these insects in the wider region of East and Central Africa.
This work was the first study that provided baseline information on the contrasting endosymbiont patterns and that confirmed the association of a distinct genetic sub group to the severe CMD pandemic in Tanzania more than a decade after similar associations were first made in Uganda
Valutazione degli effetti dei metalli pesanti e dei (PCB) sui parametri seminali convenzionali e non in soggetti residenti in un'area industriale ad elevato rischio di crisi ambientale della Sicilia Orientale ed in un gruppo di controllo (area rurale).
No full textRelazione tra i livelli nel sangue e nel plasma seminale dei Policlorobifenili(PCB) , anomalie dei parametri spermatici ed effetto negativo dei livelli di metalli pesanti negli uomini che vivono in una zona a rischio ambientale (IA) rispetto alla zona non industriale .(NIA)
Background : I bifenili policlorurati ( PCB) sono sostanze tossiche industriali , bandite dalla maggior parte dei Paesi decenni fa , altamente persistenti e onnipresenti . Molti studi hanno dimostrato elevati livelli di metalli tossici nel sangue e nel plasma seminale e ridotta fertilità nei soggetti esposti professionalmente a metalli pesanti .
Obiettivi: Indagare le relazioni tra sangue e livelli di PCB nel plasma seminale , le anomalie dei parametri spermatici e l effetto negativo dei livelli di metalli pesanti ( Pb , Cd , Hg , As, Ni ) negli uomini che vivono in una zona a rischio ambientale (IA) rispetto alla zona non industriale (NIA)
Metodo : Abbiamo reclutato 83 uomini con un range di età di 21-46 anni , che vivono a Regalbuto , una zona rurale (NIA)della Sicilia Centrale ( Italia) e 96 uomini con un range di età di 20-46 anni , che vivono a Melilli , un'area industriale (IA)della Sicilia orientale . Le concentrazioni dei metalli pesanti su sangue e plasma seminale sono state misurate da un Perkin Elmer - Elan - DRC e ICP - MS . I parametri spermatici sono stati valutati secondo le linee guida del WHO 2010. Le concentrazioni nel sangue e nel plasma seminale dei PCB sono state misurate con tecnica gas - cromatografica con rilevatore di cattura di elettroni ( ECD ) e confermate dalla lettura dei congeneri con doppia colonna.
Risultati: cinquantatre( 53 % ) uomini dell area industriale ( IA ) sono esposti professionalmente . Confrontando IA vs NIA : un astenozoospermia è stata trovata nel 58 % ( vs 23 % , p = 0,005 . ); una riduzione della concentrazione spermatica è stata trovata nel 20 % ( vs 10 % , p = 0,06 ) .
Sono stati ricontrati elevati livelli di As, Ni Se nel sangue , e Cd , As, Ni nel plasma seminale , in una percentuale significativamente più alta in IA vs.NIA . I congeneri più rappresentativi dei PCB ( 74 , IA , 105 , NIA ) . Livelli rilevabili di due o più congeneri sono stati trovati in 46 % ( IA ) e il 52 % ( NIA ) dei casi . Livelli mediani di tutti i congeneri sono stati superiori in IA vs. NIA ( 5.2 VS. 1,2 ug / L) . I congeneri più tossici e Studiati ( 118,138,153 ) sono stati trovati in concentrazioni e percentuali più elevate in IA vs NIA ad esclusione del 153 ( non trovato in IA ) .
Conclusione : I livelli dei metalli pesanti nel sangue e nel plasma seminale , l alterazione dei parametri spermatici ,sono stati osservati per lo più nella zona industriale . L'esposizione a PCB è onnipresente e potenzialmente dannoso per i parametri spermatici . I livelli di questi contaminanti nel palsma seminale sembrano essere più elevati nelle zone ad alto rischio ambientale
Definizione di un "codice di pratica" per la sicurezza e la conservazione dell'edilizia rurale tradizionale nell'area etnea
No full textIn Italia, l'edilizia rurale tradizionale costituisce un patrimonio architettonico, storico e culturale da preservare e tramandare alle generazioni future. In particolare, il presente lavoro, ha posto l'attenzione sui fabbricati rurali di tipo tradizionale dell'area etnea, realizzati con tecniche costruttive e materiali radicati nel contesto territoriale di appartenenza che caratterizzano fortemente il "genius loci". Gli interventi atti a preservare e migliorare tali edifici, di conseguenza, consentono di salvaguardare la valenza paesaggistica ed ambientale del territorio in cui essi sorgono.
Le attività di studio ed analisi delle tecniche di costruzione tradizionale e dei materiali impiegati hanno costituito una fase propedeutica alla individuazione degli interventi di recupero e conservazione e di miglioramento sismico più appropriati per gli edifici rurali tradizionali dell'area presa in esame.
Le schede tecniche proposte per gli interventi sugli elementi strutturali e decorativi dei fabbricati rurali rilevati sono rispettose delle tecniche costruttive e dei materiali impiegati e, soprattutto, del valore estetico degli edifici. L impostazione grafica di tali schede, inoltre, è stata studiata con l obiettivo di agevolare la scelta dell intervento più appropriato.
Infine, l applicazione numerica per il calcolo dei coefficienti di sicurezza relativi a un edificio campione, tra quelli rilevati, soggetto a meccanismo di collasso di primo modo ha rappresentato un applicazione finalizzata all individuazione di interventi di miglioramento del livello di sicurezza coerenti con quanto dettato dalle Norme Tecniche per le Costruzioni (D.M. 14 gennaio 2008) e dalla relativa Circolare (n. 617/2009)
Vascular dementia: from clinical to biochemical and neurophysiological markers
No full textBACKGROUND: Vascular Dementia can be considered the second most common cause of dementia after Alzheimer s disease. However, unlike the degenerative dementias, it s possible to carry out preventive strategies. Recently, neurophysiological techniques and in particular transcranial magnetic stimulation (TMS), have been tested in patients with dementia in order to pick up early cerebral functional changes. The present research aimed to investigate cortical excitability in elderly patients with leukoaraiosis
METHODS: Motor cortex excitability, intracortical inhibition and facilitation circuits and central cholinergic function were evaluated in patients with a clinical features of vascular cognitive impairment-no dementia. The neuropsychological profile and the vascular burden at brain magnetic resonance imaging were concomitantly explored.
RESULTS: No differences were found for measures of motor cortex excitability between patients and controls. A significant enhancement of intracortical facilitation was observed in patients. Moreover central cholinergic circuits seem to be spared in patients.
DISCUSSION AND CONCLUSION: This study provides the first evidence of functional changes in intracortical excitatory neuronal circuits in patients with vascular cognitive impairment-no dementia, a finding which is in line with previous research on vascular dementia. Central cholinergic functioning seems to be spared in patients. This functional integrity differs from that reported in patients with Alzheimer s disease or mild cognitive impairment, underlying the distinctive involvement of the cholinergic pathway in degenerative dementia and vascular form, even in their early or preclinical stage. The non-invasive evaluation of the pathophysiological and neurochemical mechanisms underlying dementia highlights the emerging role of TMS as a powerful tool in the diagnosis and management of different dementing processes
Analisi e sintesi di celle solari a film-sottile con nanoparticelle metalliche
No full textIn this thesis it is shown that the FEM-RBCI method can be successfully applied to the analysis of the scattering of time-harmonic electromagnetic waves at optical frequencies from metallic nanoparticles of arbitrary shape.
Moreover, the optimization of a thin solar cell with metallic nanoparticles is performed by means of Genetic Algorithms and the Finite Element Method. The goal is to design a solar cell which shows good performances in terms of sunlight absorption. Suitable Genetic Algorithms with varying crossover and mutation probabilities are employed. The optimum is reached in about half the time required by the standard procedure. The optimized solar cell performs well in the sunlight frequency bandwidth
Organizzazione di partito e postmodernità: la de-differenziazione come ipotesi di mutamento
No full textI profondi mutamenti subiti dalle organizzazioni tradizionali hanno costretto i partiti a ridefinire la configurazione delle loro strutture interne, sia territoriali sia funzionali. Dal punto di vista territoriale, si riscontra la tendenza ad alleggerire l articolazione dei subsistemi, attraverso la riduzione del numero di unità o la ricerca di formule più soft, come i centri di aggregazione tematica. Dal punto di vista funzionale (o settoriale), ciò ha comportato l esternalizzazione delle mansioni un tempo svolte all interno dei confini dell organizzazione partitica. Fra queste, l aggregazione degli interessi, la mobilitazione elettorale, la gestione della comunicazione politica, il policy making. La perdita di tali funzioni è avvenuta in concomitanza all indebolimento dei legami di appartenenza fra membership e partiti, ormai non più titolari del monopolio sulle attività di collegamento fra cittadini e istituzioni dello stato. La ridefinizione delle strutture risponde alla sovra-differenziazione e a fenomeni di ipertrofia burocratica compiutasi all interno dei partiti di massa, divenuti ingovernabili a causa di un eccessiva articolazione interna dell organizzazione che, negli anni, (hanno inquinato i meccanismi che garantivano ) compromesso la capacità di assumere decisioni in tempi ragionevoli (o di controllare le zone di incertezza). La ricerca di nuove soluzioni organizzative, flessibili e snodate, può farsi rientrare nel processo (pratica) di de-differenziazione tipico della società postmoderna, intesa come: 1) la ridefinizione dei rapporti fra i vari livelli gerarchici, sia in senso orizzontale che verticale, volta a smantellare il rigido sistema di divisione del lavoro che ha caratterizzato i partiti di integrazione di massa; 2) la tendenza a trasgredire i confini dell organizzazione attraverso la creazione di una fitta rete di scambi con l ambiente esterno. La ridefinizione delle strutture risponde alla sovra-differenziazione e a fenomeni di ipertrofia burocratica compiutasi all interno dei partiti di massa, divenuti ingovernabili a causa di un eccessiva articolazione interna dell organizzazione che, negli anni, (hanno inquinato i meccanismi che garantivano ) compromesso la capacità di assumere decisioni in tempi ragionevoli (o di controllare le zone di incertezza). La ricerca di nuove soluzioni organizzative, flessibili e snodate, può farsi rientrare nel processo (pratica) di de-differenziazione tipico della società postmoderna, intesa come: 1) la ridefinizione dei rapporti fra i vari livelli gerarchici, sia in senso orizzontale che verticale, volta a smantellare il rigido sistema di divisione del lavoro che ha caratterizzato i partiti di integrazione di massa; 2) la tendenza a trasgredire i confini dell organizzazione attraverso la creazione di una fitta rete di scambi con l ambiente esterno
Modulation of Stress Granules formation: Role of mGlu5 receptor and FMRP and implications for pathophysiology of Fragile X Syndrome
No full textFragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism. The genetic defect in FXS is a CGG trinucleotide repeat expansion (>200) in the promoter region of the FMR1 (fragile X mental retardation 1) gene; this amplification causes the absence of the encoded protein FMRP (Fragile X Mental Retardation Protein). FMRP is an RNA-binding protein involved in mRNA transport and translation. Despite numerous studies, the available treatments are only symptomatic. There is no cure to replace FMRP expression, yet. FMRP can interact with RNA-binding proteins such as FXR1P, FXR2P, NUFIP and 82-FIP, and with proteins that do not bind RNA, like CYFIP1 and CYFIP2. The interaction with these different proteins may modulate FMRP functions and its RNA affinity. A new role of FMRP in mRNA metabolism as component of stress granules (SGs) has been identified. FMRP seems to lead mRNAs in SGs upon cellular stress, during which protein synthesis is blocked. SGs are ribonucleoproteic aggregates containing translation initiation components and RNA binding proteins, like eIF2a and FMRP. Several data also indicate that some of the FXS symptoms are a consequence of a defect in group-I metabotropic glutamate receptor, namely mGlu5; pharmacological blockade of mGlu5 receptors provide a therapeutic target in FXS. mGlu5 receptor, like FMRP, regulates protein synthesis but in a functionally opponent manner: mGlu5 receptor activates protein synthesis, FMRP suppresses it. In the absence of FMRP, mGlu5-dependent protein synthesis is unchecked, with consequent excessive translation. Activation of mGlu5 receptors stimulates FMRP-mediated mRNA transport and protein synthesis, but its role in SGs formation is unknown.The aim of this PhD thesis was to better investigate FMRP function studying the relationship of FMRP with its interacting proteins and the role of FMRP in stress response under activation of mGlu5 receptor. In Paper I, we analyzed the expression pattern of FMRP and its interacting proteins in different brain areas, at different ages in wild type (WT) mice to better define the interplay between FMRP and its interacting proteins during development. FMRP was strongly expressed at P3, peaked at P7-P14 and gradually decreases thereafter. The analysis of expression pattern of several proteins carried out, indicate that FMRP and its interacting proteins have distinct developmental patterns of expression and suggest that FMRP may be preferentially associated to certain proteins in early and late developmental stages. We found that the RNA binding and cytoskeleton remodeling functions of FMRP may be differently modulated during development. In Paper II we studied FMRP under stress condition using WT and Fmr1 knockout (KO) astrocytes. We have demonstrated that the lack of FMRP impairs SGs formation and furthermore that activation of mGlu5 receptor affects SGs formation through a FMRP-mediated mechanism in WT. Interestingly, the mGlu5 receptor blockade restores SGs formation in Fmr1 KO. Also, mGlu5 receptor activation before stress reduced FMRP recruitment in SGs and phosphorylation of eIF2a and FMRP. In contrast, mGlu5 receptor activation did not affect SGs formation in Fmr1 KO astrocytes. Since phosphorylation of eIF2a and FMRP are two crucial key events in SGs formation and modulation of protein synthesis, mGlu5 receptors may act by shifting the balance from inhibition to activation of protein synthesis during stress. These findings suggest a potential novel role for mGlu receptors in SGs formation. We suggest that FMRP may have a positive role in stress response, facilitating and enhancing SGs formation to prevent stress damages. This process is useful to understand what happens in FXS, in which can occur abnormal modulation of different proteins during development with consequent abnormal response during adversal conditions, like oxidative stress that represent a frequent component in FXS and neurodegenerative disorders
Integrazione ed ottimizzazione di nuove tecnologie per impianti fotovoltaici integrati negli edifici
No full textThe following thesis deals with the energy production comparison between two different conversion technologies for photovoltaic systems: central-inverter conversion versus micro-inverter conversion.
After an analysis over the many energy production systems, the thesis focuses on photovoltaic energy systems.
The study of cell, module and system efficiencies will explain all causes of energy losses that can affect the photovoltaic energy generation.
The second part of the thesis is focused on the micro-inverter technology and the differences with the central-inverter systems.
Data analyses have been made on many systems in different locations (with almost the same sun radiation received), different azimuth and tilt angles, and different shading percentage.
The analyses will show how micro-inverter systems can improve energy production not only during shaded but also in not-shaded conditions.
At the end an economic comparison between the two different technologies will try to justify the use of micro-inverter systems not only for energy production efficiency but even for economic affordability
VDAC and SOD1: two major players in mitochondrial metabolism and in ALS
No full textThe Thesis work presented here has been devoted to two proteins, the Voltage-Dependent Anion Channel (VDAC) and the Superoxide Dismutase I (SOD1) and has been especially focused on the relationships between them in physiological or pathological conditions of the cell.
VDAC is a pore-forming protein located in the outer mitochondrial membrane, where it is suspected to play a key role in metabolism regulation, as the interface between mitochondria and cytosol, and in apoptosis regulation. In the small family of VDAC proteins, composed of three isoforms in chordates, VDAC3 is the least known. Conversely from isoforms 1 and 2, its ability to form pores has been questioned. In this thesis, we present the first complete electrophysiological characterization of VDAC3, showing that this protein is able to forms smaller pores compared to VDAC1, under physiological condition of pH. Another point examined here has been the gating of VDAC1. This protein, in vitro, shows the important feature of gating the pore in dependence of high voltage applied. It is believed that the N-terminal domain has a crucial role in voltage-dependent gating and in the stabilization of the protein through its interaction with the pore-wall.
By producing several mutants of VDAC1, in this work we have shown that the Voltage-dependence may be modulated in an asymmetrical way by modifying sequences or deleting £]-strands required for the interaction with N-terminal domain.
The Superoxide Dismutase I (SOD1) is the most important antioxidant enzyme of all eukaryotic cells, since it inactivates the superoxide anion. Many recent evidences suggest that SOD1 is important for mitochondrial function, both in physiological and pathological conditions. SOD1 protects, among others, VDAC from oxidative stress, and may affect mitochondrial proteins expression levels. In addition, in the neurodegenerative disease Amyotrophic Lateral Sclerosis (ALS), SOD1 mutants were reported to directly bind the cytosolic surface of mitochondria, using VDAC1 as docking site. To understand the relationships between VDAC and SOD1, in this work, we studied the influence of hSOD1 on mitochondria when it was overexpressed in a yeast strain devoid of yeast endogenous VDAC. Our results sturprisingly indicate that SOD1 may have a metabolic role and can support the mitochondrial recovery in the strain ´por1, heavily slowed down by the lack of porin1. Our results support the recent claim that SOD1 may act on the expression of other mitochondrial proteins. In addition, the characterization of the interaction between VDAC1 and two of the most diffused ALS-linked SOD1 mutants was also obtained and might be considered the molecular basis in understanding the mitochondrial involvement in ALS