196,598 research outputs found
The role of time versus climate in the formation of deep soils of the Apennine fringe of the Po valley, Italy
No full textTwo very deep, red soils on a loess-mantled fluvial terrace of the Trebbia River in northern Italy were sampled and analyzed to determine their history and pedologic significance. Magnetostratigraphy confirms that the upper part of the terrace gravel and all of the 4-m-thick loess cover is normally magnetized and therefore less than about 780,000 yr. Artifacts collected from the oldest loess suggest an age of about 400,000 yr for the inception of loess deposition in this area. The soil horizons in loess dominantly have argillic or albic character, with redoximorphic features that include mottles, glossic tongues, and zones of ferromanganese concretions. Soil colors become progressively redder with depth in the loess cover and are most red, a 2.5 YR color hue, in the top of the terrace gravel. The upper horizons in gravel have abundant ghosts of completely weathered marl and sandstone. Rubification and weathering of stones diminishes with depth to fresh, slightly carbonate enriched parent material at 12 m. The heavy mineral composition of the sand fraction suggests minor discontinuities in loess-derived horizons. Abundance of opaque heavy minerals and picotite, which are resistant to weathering, increases from the soil surface to the base of the loess, is highest in the upper part of the terrace gravel, and decreases from there to the C horizon in gravel. Depth functions of major elements to Si in the medium silt fraction (10-30 μm) indicate a downward increase in degree of decalcification and of dissolution of primary minerals. Micromorphology adds detail to the interpretation of these complex soils: yellow complex ferriargillans are present in almost all horizons; they are rare at the top of the sequence in loess and become progressively more abundant with depth, reaching a maximum in the upper 3 m of the gravel and then decreasing with further depth to 12 m. We interpret this peak in abundance of yellow cutans to result from long continued clay illuviation to this depth from a succession of eluvial zones in the aggrading loessial sequence above. Distinctive red, hematite-rich argillans are abundant only in the upper horizons in the gravel. The red argillans relate to initial development of the soil in gravel, because they are included as pedorelicts in the deepest loess layer, where they are embedded in the yellow argillans. Stratigraphic and pedologic evidence indicates that these soils began forming in terrace gravel for perhaps 300,000 yr during the early middle Pleistocene. From this relict core these soils continued developing, both downward by continuing deep decalcification and argilluviation and upward as a sequence of wet Alfisols developed in a succession of loess layers that began aggrading about 400,000 yr ago. A paleoclimatic record can be perceived weakly in these soils, mainly by thick horizons of Fe-Mn nodules that mark boundaries between episodes of loess deposition that took place during glacial cold phases. Paleofeatures from one unit to another are similar in kind and intensity, indicating a degree of continuity of a basic set of pedogenic processes, principally decalcification, argilluviation, and redoximorphism. These soils can be regarded as Vetusols because a single dominant set of pedogenic features are represented in all parts of these soils and deeper parts of these aggrading super profiles have never been isolated from continuing pedogenic change to the present
Ovarian endometriosis: from pathogenesis to surgical treatment
No full textPURPOSE OF REVIEW: This review analyzes the literature on ovarian endometrioma,
examining the controversies on pathogenesis, malignant transformation and
surgical therapy. RECENT FINDINGS: Recent literature reflects the necessity of
clearly defining the ethiologic and pathologic factors that determine the origin
of ovarian endometriosis and explain the increase in the condition with the
prospect of developing effective prevention therapy. The possibility that
ovarian endometriomas undergo malignant transformation is widely reported in the
literature. Recent studies underline the importance of detecting histological
differences in endometriosis (hyperplasia and atypia) and several studies of
molecular biology support the theory of genetic alterations interfering with
malignant transformation of ovarian endometriosis. SUMMARY: The surgical
approach must take into account all this information and, when the therapy is
conservative, complete excision of the disease must be laparoscopically
performed without affecting the healthy ovarian tissue
Endometrioma excision and ovarian reserve : a dangerous relation
No full textEndometrioma is one of the most frequent pathologies in gynecologic surgery. Laparoscopic cyst excision is considered the best treatment in terms of lower recurrence and improved fertility. However, it was recently questioned whether the excision of the endometrioma could decrease the function of the operated ovary and if it could affect the subsequent fertility. Even if a consistent amount of ovarian tissue is unintentionally removed together with the capsule of the cyst, resulting in does not show the follicular pattern observed in working ovaries. Currently, no definitive data clarify whether the damage to the ovarian reserve, observed in patient with endometrioma, is related to the surgical procedure, to the previous presence of the cyst, or both. Electrosurgial coagulation during hemostasis could play an important role in terms of damage to ovarian stroma and vascularization. Particular attention must be paid in presence of bilateral endometriotic cysts. In fact, an increase in premature ovarian failure rate was reported when both the ovaries are involved in surgery. Incase of assisted reproductive techniques, no clear evidence indicates which is the best approach for concomitant endometriotic cyst. On the base of these considerations endometriomas Should be treated only in case of pain, infertility, and in asymptomatic patients if the cyst diameter is greater than 4 c
Dominanza della marca e successo del cobranding: una verifica sperimentale
No full textL’obiettivo di ricerca perseguito consiste, in primo luogo, nel confermare l’effetto positivo che l’esistenza delle due fondamentali tipologie di consonanza percettiva (product fit e brand fit) può esercitare sull’accettazione di un nuovo prodotto proposto nell’ambito di un accordo di co-branding. In secondo luogo, il paper approfondisce l’impatto della dominanza della marca ospitante, al fine di verificare se e come essa interagisca con tali consonanze percettive.
Il paper è così strutturato: il paragrafo 2 sintetizza le risultanze emergenti dalle ricerche empiriche che hanno approfondito lo studio dei fattori suscettibili di influenzare il successo dei nuovi prodotti lanciati con il co-branding e le ipotesi di ricerca adottate; il paragrafo 3 illustra la metodologia d’indagine utilizzata; il paragrafo 4 analizza i risultati ottenuti. Infine, nelle conclusioni vengono discusse alcune implicazioni di marketing dell’analisi svolta
Deep soils on stable or slowly aggrading surfaces: time versus climate as soil-forming factors
No full textContinental rejuvenated mountains are represented by three types of mountain belts: the Mongolia-Siberian, Ural-Appalachian and margin-continental or East-Asian types. Orogenic belts of the Mongolia-Siberian type are when tectonic relief has clear paragenesis with deep structure. Mountain belts of the Ural-Appalachian type form in the zones of rapprochment of continental platform. Mountain belts of the East-Asian type are formed along the margins of intensive subsidences in the basins of the Pacific ocean marginal seas. The reasons and conditions for the formation of rejuvenated orogenic belts are diverse. Of great importance in their formation are the protrusions of asthenoliths (anomalous mantle) and inclined bedding of the asthenospheric roof, above which there is the development of zones of linear warping or narrow structural block uplift. -from Autho
Urge confronto tra impresa sociale e tecnologica.
No full textMentre decidiamo se e come affrontare la riflessione sul rapporto ra impresa sociale e tecnologica, o peggio ancora mentre proseguiamo in lunghe e preliminari disquisizioni tassonomiche, il discorso sulla tecnologia prosegue inarrestabile, con coerenza ed efficacia. Nel frattempo, mentre discutiamo se discuterne, la stessa parola social ha assunto nuovi significati e nuove forme d’uso, fino ad arrivare a generare una necessità di disambiguazione in Wikipedia
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