262 research outputs found
Incidence of grapevine trunk diseases on four cultivars in Sardinia, Southern Italy
Esca proper and Botryosphaeria dieback are among the most widespread Grapevine trunk diseases (GTDs), characterized by similar decline symptoms. In the present work, chronic, apoplexy and death symptoms were analysed separately in four vineyards and four different cultivars, on more than 1,000 vines per cultivar, taking into account ten-year annual surveys. The cumulative incidence of plants with chronic symptoms (CHR) reached high values on 'Sauvignon Blanc' (81.9 %), 'Cabernet Sauvignon' (79.4 %) and 'Cannonau' (66.5 %), but it was low on 'Merlot' (25.1 %). 'Sauvignon Blanc' showed the highest cumulative incidence of apoplectic events (23.1 %) and dead cordons (49.2 %), while 'Cannonau' had the greatest number of dead plants (28.8 %). In each symptom category, incidence among cultivars differed significantly according to Ï2 test at P â€Â 0.05. Annual incidence of foliar symptoms fluctuated over ten years (ranging from 0.9-9.5 % in 'Merlot' to 6.3â59.1 % in 'Cabernet Sauvignon'), mostly with regard to CHR. On average, every year only 33.9 % of plants showing CHR had expressed symptoms in the previous year, while 48.6 % did not show symptoms the following year. Conversely, most of the plants exhibiting apoplexy or death were symptomatic the previous year. According to Tuckey HSD test (P †0.05) 'Merlot' had the highest incidence of plants showing CHR symptoms for the first time (72.1 %) and of apparently recovered plants (76.3 %), while 'Cabernet Sauvignon' exhibited the highest incidence of plants showing CHR symptoms also the previous year (50.0 %). The 'Cabernet Sauvignon' attitude to show chronic symptoms with a certain continuity was also confirmed by the low incidence of plants with hidden symptoms (lack of symptoms in previously symptomatic vines). On the contrary, the incidence of acute symptoms (apoplectic events and dead plants) was quite low on 'Cabernet Sauvignon'. The present study confirms that GTD incidence is influenced by cultivar. All the cultivars assessed were susceptible, but with differences in intensity, type (chronic or acute) and fluctuation of symptoms. It cannot be excluded, however, that besides the genotype also external factors, as the vigour conferred by the type of soil or the combination with the rootstock, may have influenced the results
Dietary Nitrate: Effects on the health of weaning pigs and Antimicrobial activity on seven probiotic Bifidobacterium spp. strains
The potential role of nitrite as an antimicrobial substance in the stomach may be of some importance in the ecology of the gastrointestinal tract and in host physiology. It has been shown that nitrite, under the acidic conditions of the stomach, may kill gut pathogens like Salmonella enteritidis, Escherichia coli, Salmonella typhimurium, and Yersinia enterocolitica, whereas acid alone has only a bacteriostatic effect. An in vivo study was conducted in order to assess the effects of dietary nitrate on microbiota and on the health of the gut (particularly in the stomach and small intestine). 96 weaning pigs were fed a diet containing high nitrate levels (15 mg and 150 mg) and then challenged with Salmonella enterica serovar typhimurium.
Differences in composition of the gut microbiota were assessed by analysing samples from the pigs: To date analysis of 48 pigs has been completed.. Preliminary results demonstrated no effect on the population densities of microbial groups either from the challenge or from nitrate intake. However, increasing the time from challenge decreased either the counts of LAB in the stomach and jejunum or of clostridia in the stomach.
Bifidobacteria also decreased in the stomach contents as nitrate supplementation increased. Supplementing the feedstuff with high dietary nitrate intake and then challenging with Salmonella did not affect the gastric pH or the degree of ulceration in the pigs.
The synergistic bactericidal effects of pH, nitrite and thiocyanate on seven probiotic Bifidobacterium spp. strains were also investigated in an in vitro study.
The results of the in vitro study demonstrated that an inhibitory effect exists on the seven probiotic bifidobacteria investigated with an exposure longer than 2 hours and pH values < 5.0. Addition of thiocyanate also increased the susceptibility of the tested strains. In this in vitro study, the most resistant strains at all conditions were B. animalis subsp. lactis Ra 18 and P32 and B. choerinum Su 877, Su 837 and Su 891
Non-Invasive Survey Techniques to Study Nuragic Archaeological Sites: The Nanni ArruÌ Case Study (Sardinia, Italy)
The Italian territory of Sardinia Island has an enormous cultural and identity heritage from the Pre-Nuragic and Nuragic periods, with archaeological evidence of more than 7000 sites. However, many other undiscovered remnants of these ancient times are believed to be present. In this context, it can be helpful to analyze data from different types of sensors on a single information technology platform, to better identify and perimeter hidden archaeological structures. The main objective of the study is to define a methodology that through the processing, analysis, and comparison of data obtained using different non-invasive survey techniques could help to identify and document archaeological sites not yet or only partially investigated. The non-invasive techniques include satellite, unmanned aerial vehicle, and geophysical surveys that have been applied at the nuraghe Nanni ArruÌ, one of the most important finds in recent times. The complexity of this ancient megalithic edifice and its surroundings represents an ideal use case. The surveys showed some anomalies in the areas southâeast and northâeast of the excavated portion of the Nanni ArruÌ site. The comparison between data obtained with the different survey techniques used in the study suggests that in areas where anomalies have been confirmed by multiple data types, buried structures may be present. To confirm this hypothesis, further studies are believed necessary, for example, additional geophysical surveys in the excavated part of the site
Mineralogy of the scheelite-bearing ores of Monte Tamara, SW Sardinia: insights for the evolution of a Late Variscan WâSn skarn system
Southwestern Sardinia, Italy, hosts several skarn, WâSnâMo greisen and hydrothermal deposits related to a 289±1 Ma Late Variscan granite suite. Among them, the most representative scheelite-bearing skarns belong to the San Pietro and Sinibidraxiu localities, in the Monte Tamara area, Sulcis region. The San Pietro deposit is a typical calc-silicate skarn whereas Sinibidraxiu is a sharply bounded orebody hosted in a marble unit. Optical petrographic observations and compositional data of major and trace elements were obtained for samples from both localities. San Pietro data suggests evolution from an oxidising prograde skarn stage (andraditeâdiopside, hematite and scheelite), to progressively more reducing conditions from the early retrograde (magnetiteâcassiterite) to the late sulfide stage (arsenopyrite, stannite, molybdenite, Bi sulfosalts and ZnâCuâPbâFe sulfides); Sinibidraxiu has diffuse carbonateâquartz intergrowths pseudomorphic over an early mineral assemblage with fibrous habit, followed by abundant ore mineral precipitation under reducing conditions (scheelite, arsenopyrite and PbâZnâCuâFe sulfides). Geothermometers indicate a comprehensive temperature range of 460â270°C for the sulfide stages of both deposits. The differences between the two deposits might be controlled by the distance from the source intrusion coupled with the different reactivity of the host rocks. The San Pietro mineralogy represents a more proximal skarn, contrasting with more distal mineralogical and chemical features characterising the Sinibidraxiu orebody (lack of MoâSnâBi phases; LREEâMREEâHREE signature of scheelite). This investigation contributes for the first time to the identification of a WâSn skarn system in SW Sardinia, thereby suggesting the Monte Tamara area and its surroundings as favourable for further exploration
From mining wastes to mineral sources - investigating the REE-bearing occurrences in the ArburĂšse District (SW Sardinia)
In recent years, the search for possible sources of REE minerals in Europe involved numerous old mine
areas with high volumes of mining wastes that may offer significant amounts of Critical Raw Materials
(CRMs). In some cases, strong evidence of CRMs anomalous concentrations arises from environmental
characterization of wastes, so that an interesting problem is that of finding their sources, i.e., the original
CRMs - rich mineral phases in the residual ore. An excellent example is provided by the ArburĂšse district of
SW Sardinia, for about 150 years a major Pb-Zn source in Italy, now an area under study for remediation of
its severe environmental problems, including >10 Mt of waste deposits. The district exploited a large system
(>10 km) of low-temperature polymetallic veins hosted in Lower Paleozoic siliciclastic rocks belonging to
the Variscan Nappe zone, arranged in two main geometrical trends relative to the late Variscan Arbus pluton:
âperipheralâ and âintersectingâ. Recent investigations in the Montevecchio mine area discovered high Zn (up
to 2.65 wt.%) and Pb (1.23 wt.%) grades in stratified tailing materials belonging to the Sanna old processing
plant. Remarkably, ICP-MS analyses on the same materials revealed total REE+ Y contents attaining about
600 ppm. XRD studies confirmed a tailing composition essentially made of gangue minerals (quartz, siderite
and micas) with goethite, baryte and traces of Zn carbonates and Pb sulfates. Chondrite-normalized REE
patterns are coherent with the hydrothermal character of the source: however, both the REE mineralogical
host(s) in tailings and in the Montevecchio ore are still undetermined. In the search of REE-bearing phases
in the ores, some relevant insights are provided by studies on the southern branch of the ArburĂšse system,
where the veins of âperipheralâ system are hosted in late Ordovician-Silurian sedimentary sequences. In this
part of the district the polymetallic veins assume the character of five-elements (Ni-Co-As-Bi-Ag) veins,
with a rich Ni-Co-Fe arsenide â quartz association (1) overprinted by a Zn-Pb-Cu sulfide â siderite â quartz
association (2), very similar to that dominating in Montevecchio. Investigations in the Pira Inferida mine
sector highlighted the presence of LREE fluorocarbonates (synchysite-Ce and bastnaesite-Ce) and phosphates
(monazite) associated with rutile and apatite. LREE minerals have been detected by SEM-EDS as tiny crystals
in the quartz-sericitic gangue of the Montevecchio-type (2) mineral association. The same minerals are found
in millimetric aggregates in the oxide zone of the veins, sporadically reported by mineral collectors in other
mine sites of the same system. Overall, these occurrences, similar to those found in other low-temperature vein
systems of Sardinia (e.g., Silius vein system), appear reliable mineral REE sources for Montevecchio mine
wastes; they may be therefore used as proxies for REE exploration and assessment in the district
Measuring public value: a conceptual and applied contribution to the debate
Countries facing austerity measures need to create public value. Academics and practitioners have been discussing the ways in which public value can be created, managed and measured. This paper contributes to this conversation by proposing a public value measurement model. An Italian case study is presented to demonstrate the feasibility of the model and the organizational implications when public value measures are available to public sector managers, politicians and the public
Measuring public value: a conceptual and applied contribution to the debate
Countries facing austerity measures need to create public value. Academics and practitioners have been discussing the ways in which public value can be created, managed and measured. This paper contributes to this conversation by proposing a public value measurement model. An Italian case study is presented to demonstrate the feasibility of the model and the organizational implications when public value measures are available to public sector managers, politicians and the public
Feasibility study (I stage) of CO2 geological storage by ECBM tecniques in the Sulcis Coal Province (SW Sardinia).
An ECBM feasibility study started for the Sulcis Coal Province (SW Sardinia, Italy): available geochemical, structural-geology, stratigraphic and reservoir engineering considerations as well as the newly gathered experimental data are discussed, including: fluid geochemistry (major and minor elements, dissolved gases, C and He isotopic ratios) of different strata/reservoir, coal composition and experimental data on CO2/CH4 adsorption-desorption on coal. A MapInfo GIS structure was built up including stratigraphic, geo-structural, hydro-geochemical, coal-compositional and environmental-impact information as well as the CO2 sources location and typology. Despite preliminary, these data highlighted both the challenging positive and negative aspects of the Sulcis Coal Province versus the exploitation of the ECBM technique. The most important objective of this phase I of the project is the selection of the best Sulcis ECBM test-pilot site, which will be followed (Phase II-2007) by the choice of a scaled up site and possibly by a future network (Phase III-2008). CO2 geological storage and CH4 production potentials in Sulcis have been grossly evaluated as a whole, in the frame of the Sardinia region CO2 sources, including the coal-fired power plants, both existent and foreseen (hundreds of millions of tonnes of CO2 are possible to be stored underground in the next decades).UnpublishedTrondheim, Norway4.4. Scenari e mitigazione del rischio ambientaleope
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