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Preparazione e caratterizzazione di due sistemi carrier: beads a base di chitosano e chitosano/alginato; nanoparticelle di N-trimetilchitosano
Get PDFChitosan is a very attractive polysaccharide and it is known to be a favorable pharmaceutical material because of its low toxicity, biodegradability, biocompatibility,
mucoadhesivity and natural origin. Therefore it forms an ideal hydrophilic carrier system. In this study we described the preparation and characterization of two carrier systems, chitosan and chitosan – alginate beads, and N-Trimethyl Chitosan (TMC) chloride nanoparticles.
We realized spherical beads using different polymeric dispersions, chitosan, alginate and chitosan - alginate mixture, to investigate their effect on the phytoterapic anti- inflammatory agent delivery. The main purpose of the present in vitro study is to have some information about their stability in the gastrointestinal tract and to formulate a drug delivery system for the oral administration of this phytoterapic agent. Alginate
beads were prepared by ionotropic gelation in presence of CaCl2 and BaCl2 solutions; chitosan beads were prepared by using a TPP (tripolyphosphate) solution as an ionic
cross-linking agent and acetone as a coacervating agent; beads of chitosan - alginate mixture were prepared according to the two combined procedures reported above.
The swelling degradation behaviour of the bead samples and drug release were investigated using four different medium solutions (PBS pH 7.4, HCl 0.1N pH 1, buffer pH 5). TMC with different degrees of quaternization were synthesized and characterized by 1 H- NMR spectroscopy, XRD and viscosity. Trimethyl Chitosan chloride nanoparticles (TMC-NPs) were prepared according to the ionotropic gelation process of TMC with TPP. The aim of this study is to characterized TMC-NPs (particle size -Z-average mean-, PDI and zeta potential) and evaluate their potential for brain delivery
Populations studies on two endemic taxa of southwestern Sardinia: Dianthus morisianus Vals. (Caryophyllaceae) and Anchusa littorea Moris (Boraginaceae)
Get PDFIn the Mediterranean region as elsewhere, intense coastal development has resulted in widespread modification of coastal ecosystems. Here, coastal sand dunes represent an extremely vulnerable habitat to many forms of disturbance, including those connected with recreational tourism which in
recent years has increasingly contributed to the destruction and fragmentation of natural coastal habitats.
This study concerns two narrow endemic plants growing on coastal dune systems of southwest Sardinia. Anchusa littorea Moris is a short-lived species of open dunes and D. morisianus is a perennial species which grows on stabilized dunes. The only natural populations of these species are located in southwest Sardinia. Like many other rare species of this type of habitat we know little
of the reasons for their extreme rarity, making it difficult to identify and recommend conservation actions. The thesis provides a detailed investigation of the population ecology of the existing populations of the two species with the aim of identifying the constraints on their viability. Specifically, the aims of the present study were to analyze the following features:
To investigate the conservation status of this species;
To individuate and quantify the main threats acting on this population;
To analyse some critical stage of their life-cycle (i.e. modeling of emergence and germination);
To evaluate the phenological pattern;
To propose adequate conservation measures.
Three years of study has been reveal some critical elements in the ecology of the species and their rarity and the investigation of each biology aspect about these psammophilous endangered plants yielded the information needed in order to identifythe critical aspects that affect the survival and toguide the proposal and implementation of conservation measures
Politiche e strumenti per la reinterpretazione dei paesaggi produttivi estrattivi in ambito costiero: la Sardegna come caso di studio nel contesto euro-mediterraneo
Get PDFThe research deals with the subject of protection, development and reuse of disused extraction landscapes; the overall aim is to develop policies and tools for the reinterpretation of these areas through proposals which are able to take the opportunities arising from a systemic and interdisciplinary approach. The study analyzes both ancient and modern quarries, in accordance with the definition suggested by the research and highlights, through context analysis, the different methodological approaches aimed at
tackling the main issues of the disused quarry sites. The sphere of analysis is that of coastal areas, with particular reference to the situation in Sardinia. The regional case of study, and the specific case of the city
of Cagliari, allow to contextualise the planning scenario, offering the opportunity to verify the effectiveness of policies and tools which are already in place and to define new operational proposals. The experiences analysed provide the elements needed to set up guidelines, designed as support instruments for the policies for reinterpretation of the quarry areas. The guidelines are put together using a
multi-criteria evaluation model based on the Analytic Hierarchy Process (AHP) (Saaty, 1980, 1988, 2001); this experimentation uses a scientific method and guarantees the identification of functional criteria for the definition of intervention priorities and long-term policies to be implemented in disused areas. The sites under examination are characterized by the presence of features related to the extractive history which deserve to be valued even if the quarries have ceased their activity in recent years.
The research codifies existing policies and tools which support the reinterpretation of the quarry areas, the
critical issues related to the processes, the opportunities arising from the scenario which has been analysed, and missed opportunities. The problematic issues which are found are addressed by proposals aimed at encouraging the paths of intervention in quarry sites and formulating policies and tools in structured paths. These proposals are aimed at outlining scenarios which are compatible with the territorial dynamics in place, and with renewed principles of protection and enhancement of the landscape, in order
to overcome the fragmentation of the planning framework that emerges clearly from the performed context analysis
Incremento dei tempi di attesa alla richiusura degli interruttori MT per il miglioramento della continuità del servizio
Get PDFThe large deployment of network automation with reclosing practices has been the usual solution adopted by distributors to achieve the goal of providing a distribution network with high performances in terms of number and duration of interruptions. In particular, the usual practice adopted by distributor when managing faults in distribution circuits consists in clearing the faults by the immediate tripping of one or more circuit breakers, and re-energize the lines after the automatic reclosing time. In distribution networks the reclosing time of a circuit breaker is typically 300 milliseconds, that is the shortest permissible time in which the circuit breaker need to reclose. Various studies have shown that up to as 90% of faults on most distribution overhead lines are transient (e.g. insulator flashover, contact with foreign objects like animals and trees, etc.) and transient faults can be cleared by momentarily de-energizing the line, in order to allow the fault to extinguish, autoreclosing can then restore service to the line. Autoreclosing success rates vary depending on several technical and environmental (temperature, pressure, humidity, etc.) parameters, but the majority of faults can be successfully cleared by the proper use of tripping and autoreclosing. In the paper the authors evaluate the possible benefits of adding an external time delay to circuit breaker reclosing procedure. The goal of this additional delay is to be reasonably sure that the arc at the fault location will not reignite at the reclosing instant creating a second fault, and, then, obtain significant benefits on continuity of service.
In order to deeply investigate the problem, an arc model is first developed by using the Electromagnetic Transient Program EMTP-RV, and, then, the fault model is incorporated at different locations of a 20kV Medium Voltage (MV) network with real size characteristics. Faults in insulated and resonant grounding networks of different characteristics (OHL lines and cables) are investigated.
The findings of the study are that an increased reclosing time may have a significant effect in increasing the number of self-extinguish faults, especially in transient double-phase faults in metal enclosed electrical installations. The strategy of extending the switching reclosing time may permit reducing the number of transient faults that reignite after reclosing, permitting to significantly reduce the outage time due to faults and providing a higher level of service continuity to customers
Analisi demografica della longevità in Sardegna
Get PDFOne of the most important demographic phenomena that has been occurring in industrialized countries since mid-last century is a progressive increase of life expectation (Oeppen and Vaupel, 2002; Candore et al., 2006). This trend in the last few decades, has made possible to certify a progressive increase in the life expectancies of individuals who have achived and perhaps exceed hundred years of age. It is now widely recognized as the life expectancy is influenced by a combination of genetic and environmental factors, but is not yet certified whether these features are determinig to obtain extreme longevity.
In the Italian context several studies about centenarians have been proposed (Caselli et al., 2000; Passarino et al., 2002; Gueresi et al., 2003; Magnolfi et al., 2007), particularly regarding the insular region of Sardinia (Deiana et al., 1999; Poulain et al., 2004). The main aim of the present study is to verify the presence and persistence of a high-longevity area in Sardinia. Our dataset comes from ISTAT (Italian National Institute of Statistics), regarding Census and Inter-census estimation. From this dataset it is possible to recompose the distribution by sex and age of municipal population, even analysing the sex ratio F/M. Basing on the results obtained it has not been found in the whole Sardinian territory a storical-geographical area where there is a particular high correspondence between centenarian people and the whole population in every period examined. The presence of long-lived individuals concentrated in precise geographical areas could be considered a casuality, while the results do suggest a distribution of the centenarians among the small municipalities (less than 2500 inhabitants)
Two generalizations of the skew-normal distribution and two variants of McCarthy's theorem
Get PDFThe thesis is structured into two main parts. The first and major part is concerned with the skew-normal distribution, introduced by Azzalini (1985) [6], while the second one is connected with the scoring rules. In part one the problem of finding confidence intervals for the skewness parameter of the skew-normal distribution is addressed. Two new five-parameter continuous distributions which generalize the skew-normal distribution as well as some other well-known distributions are proposed and studied. Some mathematical properties of both distributions are derived. Part two is focused on the extension of the theorem of characterization of scoring rules, due to McCarthy (1956) ([16] of part 2), in two directions: for countable infinite sample spaces, but with bounded score and for finite sample spaces, but with unbounded score
The only truly alien planet is earth: J. G. Ballard, dalla fantascienza al mainstream tra romanticismo e surrealismo
Get PDFAs an author J. G. Ballard used to deal with different genres and topics, producing several short stories and a number of novels. Yet he has always been true to himself. He started as a science fiction writer, which in a sense he was until the end. With some occasional romantic references, over the years Ballard’s fiction ranged from a personal surrealistic mood to novelized autobiography. He also had a keen interest in psychopathology and society, while being somehow haunted by his experience as a civilian prisoner of war in his early teenage years. This study shows how, like a chameleon, he often appeared under different guises, but always stayed undisputedly ‘Ballardian’
Scritture d'attore: rifrazioni artudiane nel teatro italiano (Carmelo Bene, Rino Sudano, Societas Raffaello Sanzio)
Get PDFAn ancient inside out philosopheme, CHORA, extrapolated from Timeo and utilized as a virus undermining the inside of platonic metaphysics; the protomodern and criticism’s notion, the SUBJECTILE, taken away from art of painting or sculpture and applied to the theatre; and two exquisitely theatrical concepts, OB-SCENE and FOURTH WALL: the concerted involvement of these four, seemingly heterogeneous, conceptual instruments makes it possible to find out the core of Artaud’s theatricality to be as glacial as the extremely rarefied stage wich Rino Sudano ob-
scenely trod; the PHONÉ, dear to Carmelo Bene, far from being the voice, to be its rest; and behind the rest; and behind the iconic proliferation in the Socìetas Raffaello Sanzio’s scene the contrary to hide it self: namely a loathing for the neurotic contemporary compulsion in bringing forth images
Gramsci e il circolo di Bachtin
Get PDFThere are many reasons for comparing Gramsci and the members of the so called Bachtin’s circle – i. e., Michail Bachtin, Valentin Vološinov and Pavel Medvedev. This study explores some of these reasons. Although very different thinkers, Gramsci and the Bachtin’s group shared a similar intellectual heritage and developed many close formulations about the relationship between language, ideology and hegemony. They adopted a similar key notion that a language embodies a worldview and emphasize that translation is not a question of transferring content from one language to another. This study also shows the importance of Gramsci and Bachtin’s relationship between science, reason and language. This relationship is conceived by them both as a process of translating different languages. The present work concludes with the identification of characteristics shared by the philosophers regarding their translation’s theory and the possibility of using translation for political agenda and political engagement
Quantitative status, vulnerability and pollution of groundwater resources in different environmental and climatic contexts in Sardinia and in Ethiopia
Get PDFThe Raya Valley is located in the northern part of Ethiopia within the Regional State of Tigray. The valley is part of the series of grabens at the western margins of the Afar Depression. Rainfall in this area is erratic both in time and space; hence it has suffered from a number of severe droughts and associated famines, and is chronically food-insecure. The surface water resources are characterized by streams, which flow strongly during the short rainy season and no perennial flow of surface water there is during the dry period, except the minor seepages that die out within a short distance in the valley. Therefore, groundwater is the only source for both domestic and irrigational development. Previous studies were confined to developing these resources. Hence, the objective of this research, in the Raya Valley, is to understand and to characterize the groundwater system of Raya Valley, using hydrogeology, groundwater chemistry and
isotope hydrology tools and to come up with different options that may help to monitor for efficient management of the groundwater. In the meantime, this work incorporated water balance evaluation and identification of the degree of vulnerability to contaminants of the Rio Mannu di Pabillonis Basin in the central part of Sardinia, Italy. Finally corresponding results were compared in relation to their climatic differences. Field traverses have been undertaken to collect relevant information regarding geology, hydrology, and hydrogeology in the Raya Valley (in 2009, 2010 and 2011) and in the Rio Mannu di Pabillonis Basin (in 2010 and 2011). An inventory of groundwater levels of boreholes and springs was made. Land-use was also
investigated during field visits to be used as ground truth for the verification of existing maps. The isopiezometric/static water level contour maps show that the groundwater flow toward the centre and then all flow to the south in a similar fashion to the surface water, in the Raya Valley. In the Rio Mannu Basin, the groundwater flow direction is also to the centre of the basin and finally toward the north, following the topographic gradient.
Water samples, from Raya Valley and Rio Mannu Basin, were collected and analyzed and results were compared with Ethiopian and Italian drinking water standards, respectively. For most of the chemical constituents, water samples are within the safety standards with regard to the Raya Valley, whereas some elevated NO3- values have been noticed in areas where the dominant activity is animal farming in Rio Mannu basin. In situ water temperature and electric conductivity measurements in the Raya Valley have
shown distinct zonation along west to east, with the highest values recorded in the east. In the meantime,
Ca-HCO3 water type dominates the western boreholes and springs, while Na-Cl-SO4 water type dominates the eastern boreholes and springs. The dominant water type is Na-Cl in Rio Mannu Basin. Rain water samples of two consecutive rainy seasons (2009 and 2010) from different elevations were
analyzed for stable isotope (oxygen and hydrogen). The results were used to construct a Local Meteoric Water Line (LMWL) of the area. Additional 17 borehole and 3 spring samples were collected and analyzed for the same isotopes in the same laboratory. Correlation between δ 18O and δ2H (LMWL) is δ2H = 7.4756 δ18O + 11.827, (r2= 0.9959) and hence the later data were plotted alongside the meteoric water to define the possible sources of the groundwater recharge in the area of interest. Most of the borehole and spring samples plotted nearly along the local meteoric water line. But, the eastern boreholes and the hot spring, in the east, plotted away from the LMWL in the direction of higher water-rock interaction, with regression
equation δ18O and δ2H (LMWL) δ2H = 6.7244 δ18O – 0.0795, (r2= 0.998). This indicates the existence of another source of water recharge to the Raya Valley. The Thornthwaite and WetSpass models were applied to simulate the hydrological water balance of both areas. In the Thornthwaite method the water balance was made using average, less than and greater than average precipitations in order to observe which of the water balance components are more affected positively or negatively. Thus the results signify that Cumulative Available Water is more sensitive to variation in precipitation and follows the same direction of precipitation, while Actual Evapotranspiration follows the reverse way, i.e. it decreases when precipitation increases and vice-versa. Thus, 86.5% of the average precipitation is lost as evapotranspiration, 4.3% becomes surface runoff; and 9.2% is groundwater recharge in the Raya Valley. Meanwhile, it is 73.5% for evapotranspiration, 11.8% for surface runoff, and 14.7% for groundwater recharge in the Rio Mannu Basin. Seasonal and annual evapotranspiration, surface runoff, and groundwater recharge are the main outputs of the WetSpass model. Accordingly, 81.1% of the precipitation in the basin is lost through evapotranspiration, 5.9% becomes surface runoff, and 12.9% is groundwater recharge in the Raya Valley. And 54.4% of the
precipitation in the basin is lost through evapotranspiration, 6.8% becomes surface runoff, and 39.8% is groundwater recharge in the Rio Mannu Basin.
The intrinsic vulnerability map of the Raya Valley was prepared using SINTACS program with the help of
ArcGIS. After running the model, the areas inherently vulnerable where rated as very low to high based on
the results of the model. The alluvial deposit, including the Gerjalle swampy area, was rated as high vulnerable, demonstrating the higher risk in the main target area of the valley. The Raya Valley is a graben running parallel to the western escarpment of the Afar Depression, in a north-
south direction. Description of the local geology and cross-sections along different orientations elucidate
that the valley floor is mainly composed of basin fill deposits underlain by moderately to highly fractured
basalt. The thickness of the alluvial deposit is variable and ranges from about 18 to more than 311 meters. The minimum thickness is in the western and eastern flanks of the valley, whereas the maximum thickness is obtained towards the eastern part of the valley center. No significant impermeable layer that can act as a confining bed is observed. The gradient of the alluvial sediment is low (0.006 in a total length of over 60 kilometers along the flow direction) and the alluvial aquifer is inter-granular containing gravel, sand and with some intercalation of silt and clay. The groundwater recharge, as explained above, has two sources, precipitation and groundwater inflow. Therefore, the surface water divide does not coincide with the groundwater divide.
The hydraulic conductivity is variable both in lithology and space, thus it varies between 0.03-0.37 m/day in
the volcanic rocks, and 0.11-26 m/day with mean value of 2.8 m/day, in the alluvial sediments. Evidences from boreholes pierced in the volcanic rocks, beneath the alluvial sediments, show significant quantities of water. Therefore, an attempt to mathematically model the area should verify the groundwater inflow and consider the weathered and fractured part of the volcanic rocks as a second aquifer