102,240 research outputs found
Preferenze monetarie per la tutela del paesaggio nei conetti vulcanici pedemontani etnei: primi risultati di un esperimento di scelta
No full textPreferenze monetarie per la tutela del paesaggio nei conetti vulcanici pedemontani etnei: primi risultati di un esperimento di scelt
Il valore economico del paesaggio agrario siciliano – Tre casi di studio
No full textQuesto volume riporta i risultati di tre applicazioni dei metodi di stime "stated preferences" che si riferiscono a tre ambiti significativi del paesaggio sicilian
Razionalità e stabilità delle preferenze espresse negli esperimenti di scelta. Una verifica mediante le alternative decoy
No full texthis paper reports on an empirical test aimed at verifying rationality of stated preferences in choice experiments. The test has been conducted by overlapping two applications of choice experiments. The former has been set up accord- ing standard practice. The latter has been set up and im- plemented by including choice tasks with decoy alterna- tives. The design of the test allowed to identify in the sam- ple a signifcant proportion of respondents with anomalies in their stated preferences, to classify these anomalies, to search for their possible causes, and to assess their effects on willingness to pay estimates
Lectin-induced oxidative stress in human platelets
No full textPreviously we have shown that wheat germ agglutinin (WGA) and, with minor potency, Phaseolus vulgaris agglutinin (PHA), but not lens culinarian agglutinin (LCA), induce platelet aggregation, through the PLCƴ2 activation by the concerted action of src/syk and PI3K/BTK pathways. In this study, we have investigated platelet oxidative stress induced by lectins. Several parameters indicative of oxidative stress, such as reactive oxygen species (ROS), superoxide anion, lipid peroxidation and the efficiency of the aerobic metabolism, have been measured. It was found that ROS, superoxide anion formation and lipid peroxidation are significantly increased upon platelet treatment with WGA and PHA while LCA is ineffective. WGA is always more effective than PHA in all experimental conditions tested. In addition, the involvement of NADPH oxidase 1, syk and PI3K in oxidative stress induced by WGA and PHA has been shown. Concerning the lectins effect on aerobic metabolism, WGA and PHA, but not LCA, act as uncoupling agents, determining an increase of oxygen consumption and a decrease of ATP synthesis, with a consequent decrease of P/O value. These results are confirmed by the impairment of platelets proton gradient formation, evaluated by membrane potential, in platelets treated with WGA and PHA. In conclusion lectins, especially WGA, induce oxidative stress in platelets and decrease energy availability through modifications of membrane structure leading to the inefficiency of the aerobic machinery that steers platelets toward death as suggested by the decreased metabolic activity of platelets and the increased lactic dehydrogenase release
Modulation of L-arginine transport and nitric oxide production by gabexate mesylate
No full text: Gabexate mesylate, a non-antigenic synthetic inhibitor of trypsin-like serine proteinases, is a drug used efficiently in the treatment of pancreatitis and disseminated intravascular coagulation and as a regional anticoagulant for haemodialysis. Considering the structural similarity between L-arginine and gabexate mesylate, the effect of this drug on L-arginine transport, nitric oxide (NO) formation and constitutive NO synthase activity in human platelets was investigated. Data have shown that gabexate mesylate inhibited competitively L-arginine uptake by increasing the K(m) value from 22+/-2 to 86+/-6 microM. The K(i) value was 158 microM at pH 7.4 and 37 degrees. Furthermore, gabexate mesylate decreased dose and time-dependent nitrite and nitrate formation (NO(x) release) and cGMP accumulation in whole cells. In addition, gabexate mesylate inhibited constitutive nitric oxide synthase in a cell-free extract. We concluded that gabexate mesylate could be considered an effective modulator of cellular NO synthesis
Il valore della funzione paesaggistica del pistacchio sull’Etna
No full textIn quest6o contributo si illustrano i risultati di una stima del valore4 monetario del paesaqgio agrario della coltivazione del pistacchio, che, per caratteri di natura intrinseca ed in relazione ad evidenti fat6tori di rarità e diversità, possiede valenze storico-culturali ed estetiche, prima ancora che economiche, non trascurabili
Valutazione contingente del paesaggio agrario della Costa Viola
No full textIn questo capitolo vengono illustrati e discussi i principali risultati di un esercizio di misurazione della percezione sociale e del valore economico di un paesaggio culturale significativo della costa calabrese
Prognostic value of cyclin D1, p27 and Ki-67 in mammary tumours in the dog: an immunohistochemical approach
No full textThe Ricardian analysis twenty years after the original model. Evolution, unresolved issues and empirical problems
No full textThis paper analyses the wide body of literature that concerns applications of the Ricardian approach to
assess the economic effects of climate change on agriculture. Beginning with the original model
proposed by Mendelsohn, Nordhaus and Shaw in 1994, the article discusses researchers’ main
criticisms of the model and the innovations suggested to overcome its limitations. Finally, the study
summarises the unresolved issues and empirical problems that need to be examined in future research.
New issues to be explored include the capture of future technologies, implementation of price changes,
choice of the best variables to represent climate, simulation of seasonal effects and identification of the
best technique to hypothesise the relationship between profits and climate. The paper also discusses
operative problems, such as the availability of the most suitable data, the adoption of spatialisation techniques and the enlargement of the time horizon to be covered
Measuring the effect of climate change on agriculture: A literature review of analytical models
No full textThis article provides a short overview of the princ
ipal models that can be used to estimate the effect
s of
climate change on agriculture. The models are class
ified in relation to the following criteria: the sp
ecific
impacts they aim to assess, their ability to measur
e production and/or economic losses, and the
adoption of social indicators of the effects and re
sponses. The weaknesses and strengths of the
models are also identified and discussed. The most
relevant factors for the choice of the most
appropriate model are analysed. Through a comparati
ve analysis of the literature, an easily adoptable
scheme for selecting the most appropriate method to
estimate the effects of climate change according
to the characteristics of the case study is identif
ied. The adopted classification scheme demonstrates
that one model is capable of simultaneously conside
ring many aspects related to climate change and
classifying these in different class
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