368 research outputs found
L’ambiente carsico e l’idrogeologia dei gessi di Sassalbo (MS)
Nel Canale dell’Acqua Torbida (Alta Lunigiana), si trova
il maggiore affioramento di evaporiti triassiche della Toscana.
Rispetto ai gessi dell’Alta val Secchia (RE), di cui
sono il lembo meridionale, appaiono molto meno tettonizzati.
L’area carsica, che comprende in prevalenza calcari
cavernosi, ha una superficie complessiva di circa 2,2 km2
in cui sono ben rappresentate forme carsiche superficiali,
sia macro che micro. Anche i fenomeni carsici sotterranei
sembrano essere ben sviluppati: la loro genesi è stata attribuita
a periodi di avanzata e arretramento dei ghiacciai
durante l’ultimo glaciale. Attualmente nel catasto toscano
sono registrate 5 cavitĂ , di cui 4 rilevate.
Nell’ambito del Progetto Trias II (studio interdisciplinare
svolto dalla SocietĂ Speleologica Italiana per conto del
Parco Nazionale dell’Appennino Tosco-Emiliano) è stato
possibile studiare l’area dal punto di vista morfologico,
speleologico e idrochimico, monitorando in continuo alcune
delle principali risorgenti carsiche parallelamente ai
torrenti cui esse potevano risultare connesse.
Nel presente lavoro, dopo breve illustrazione delle morfologie
epigee ed ipogee, vengono presentati i risultati del
monitoraggio idrologico. Le analisi hanno permesso di
evidenziare come in molti casi le acque del carso di Sassalbo
siano chimicamente molto simili a quelle del sistema
ad ansa ipogea del Tanone della Gacciolina in Alta val di
Secchia. Fanno eccezione altre sorgenti, alimentate quasi
esclusivamente dalla serie marnoso arenacea e dal macigno,
che presentano comportamenti idrodinamici differenti
in funzione dei loro specifici bacini di alimentazione.Karst and hydrology of the Sassalbo Gypsa (Massa Carrara
– Italy)
The largest triassic evaporitic outcrop of Tuscany is located
inside the Acqua Torbida creek (Upper Lunigiana).
They represent the southernmost and less tectonized part
of the Upper Secchia Gypsa (RE). The karst area (some 2,2)
consists mostly of limestone (Calcari Cavernosi) with well
developed macro – and micro – forms. The underground
phenomena are mainly related to the mouventes of glacial
tongues during the last Glacial. 5 cavities are presently
known and inserted in the Tuscany Cadaster, 4 of which
mapped. In the framework of the Trias II Project (an interdisciplinary
study sponsored by the Appennino Tosco-Emiliano
National Park and performed by the Italian Speleological
Society) this area has been investigated from the
morphological, speleological, hydrochemical point of view
while some of the major springs and related rivers were
monitored. In the paper after a short description of the epigean
and hypogean forms, the achieved result during the
hydrological study are presented. This study evidenced
that in many occurrences the behavior of the Sassalbo
karst waters is very similar to that of the Tanone della Gacciolina
cave in the Upper Secchia Valley. Only a few springs
exhibit a different behavior being rather completely fed
by the marnoso-arenacea and macigno formations
Fatigue investigation at high load ratio R of a quenched and tempered chromium molybdenum steel
Abstract The fatigue behavior at high number of cycles in elastic-plastic field of quenched and tempered carbon chromium steel was experimentally investigated for high performance reciprocating compressors application. Fatigue tests on un-notched specimens were performed both under load and strain controls, by imposing different levels of stress/strain and for each of them different values of stress ratios R, especially high values. Stress and strain trends have been monitored, during the fatigue life, and either ratcheting or relaxation, respectively, was evident. The stress control tests have resulted into fatigue fractures only for low values of R with significant ratcheting and an increasing rate during the final part of the test, thus the fracture could be considered as a synergy between fatigue damage and plastic failure. On the contrary, the ratcheting stabilized for high values of R and the tests were finalized without any fracture. Within an intermediate region, for medium/high values of R, a minor ratcheting and the fracture transition have been found. Similarly, for the tests under strain control, low values of R showed fatigue fractures despite a considerable relaxation, conversely for high values of R, the relaxation was limited without any fracture. After reporting the tests on the Haigh plane, the Smith-Watson-Topper equation (SWT) provided the best prediction of the fatigue strength, at least until the intersection with the ultimate stress line, both under stress and strain control loadings. The cyclic behavior of the material was then investigated through several static and cyclic tests on plain specimens. A kinematic hardening Chaboche model, with three parameter couples, was proposed and the values of these parameters derived and discussed. Finally, other tests have been conducted on notched specimens with C geometry and blunt radius, again at high R values. FE analysis allowed the prediction of the stress evolution during the loading cycling, implementing the Chaboche model, and observing a combined effect of ratcheting and relaxation at the notch tip. The stabilized stresses were finally reported on the Haigh diagram and the results were found in agreement with the plain specimen fatigue line
Rapid and sound assessment of well-being within a multi-dimensional approach: The Well-being Numerical Rating Scales (WB-NRSs)
The assessment of well-being remains an important topic for many disciplines including medical, psychological, social, educational, and economic fields. The present study assesses the reliability and validity of a five-item instrument for evaluating physical, psychological, spiritual, relational, and general well-being. This measure uniquely utilizes a segmented numeric version of the visual analog scale in which a respondent selects a whole number that best reflects the intensity of the investigated characteristic. In study one, 939 clinical (i.e., diagnosed with cancer and liver disease with cirrhosis) and non-clinical (i.e., undergraduate students and their family and acquaintances) participants between the ages of 18 to 87 years (M = 47.20 years, SD = 19.62, 54% males) were recruited. Results showed items have strong discriminant ability and the spread of threshold parameters attests to the appropriateness of the response categories. Moreover, convergent and discriminant validity were found with other self-report measures (e.g., depression, anxiety, optimism, well-being) and the measure showed responsiveness to two separate interventions for clinical populations. In study two, 287 Canadian (ages ranged from 18 to 30 years; M = 20.78, SD = 3.32; 23% males) and 342 Italian undergraduate psychology students (age ranged from 18 to 29 years, M = 21.21 years, SD = 1.73, 38% males) were recruited to complete self-report questionnaires. IRT-based differential item functioning analyses provided evidence that the item properties were similar for the Italian and English versions of the scale. Additionally, the validity results obtained in study one were replicated and similar relationships between criterion variables were found when comparing the Italian- and the English-speaking samples. Overall, the current study provides evidence that the Italian and English versions of the WB-NRSs offer added value in research focused on well-being and in assessing well-being changes prompted by intervention programs
CA-IX-Expressing Small Extracellular Vesicles (sEVs) Are Released by Melanoma Cells under Hypoxia and in the Blood of Advanced Melanoma Patients
Cutaneous melanoma is a highly aggressive skin cancer, with poor prognosis. The tumor microenvironment is characterized by areas of hypoxia. Carbonic anhydrase IX (CA-IX) is a marker of tumor hypoxia and its expression is regulated by hypoxia-inducible factor-1 (HIF-1). CA-IX has been found to be highly expressed in invasive melanomas. In this study, we investigated the effects of hypoxia on the release of small extracellular vesicles (sEVs) in two melanoma in vitro models. We demonstrated that melanoma cells release sEVs under both normoxic and hypoxic conditions, but only hypoxia-induced sEVs express CA-IX mRNA and protein. Moreover, we optimized an ELISA assay to provide evidence for CA-IX protein expression on the membranes of the sEVs. These CA-IX-positive sEVs may be exploited as potential biomarkers for liquid biopsy
- …