197,362 research outputs found
Le facies a macroforaminiferi del Paleocene-Eocene del Gargano meridionale.
No full textGuida alle Escursioni (a cura di Pavia M. & Zunino M.
Eocene/Oligocene deep-water agglutinated foraminifera (DWAF) assemblages from the Madonie Mts.
No full textQuantitative and qualitative analysis of deep-water agglutinated foraminifera (DWAF) assemblages from Portella Colla (Madonie Mts.) reveal a variation of the trophic continuum in Late Eocene and Early Oligocene times (Benedetti & Pignatti in press).
Twenty-nine samples were processed obtaining 80 agglutinated species, 13 of which in open nomenclature, belonging to 34 genera, which were attributed to the functional morphogroups of Jones and Charnock (1985). Only 7 genera of hyaline benthic foraminifera are recorded. Faunal density increases upsection, whereas specific diversity fluctuates and reaches its minimum near the E/O boundary.
In the uppermost Eocene, cyclamminids, Haplophragmoides and Repmanina charoides (Jones & Parker, 1860), epifaunal and lower infaunal forms prefering well-oxigenated bottom water and a normal food supply, prevail. Near the E/O boundary diversity broadly decreases and the assemblages are dominated by opportunistic taxa such as Repmanina charoides. At the beginning of the lower Rupelian, suspension-feeders (group A) and assemblages rich in Paratrochamminoides are present and hyaline taxa disappear.
At the end of the lower Rupelian, Nothia, ammodiscids and hyaline foraminifers reappear and deep
infaunal morphogroup becomes dominant marking low oxygen bottom water condition. In the upper Rupelian deep infaunal communities (rheophacids and Caudammina) dominate the assemblages and epifaunal surface-dwelling foraminifera decrease.
At the sandy input increase (transition from Caltavuturo Fm. to Portella Colla Clays) correspond the LO of Caudammina, suspension feeders and surface-dwellers decrease, oligotypic assemblages are dominated by Reticulophragmium rotundidorsatum. The oxygen bottom water conditions return to tenors similar to those of the upper Eocene, with a medium to high nutrient supply as inferred from the abundance of cyclamminids
Can the surgical tourniquet be used in patients with sickle cell disease or trait? A review of the literature.
No full textIntroduction: In patients with sickle cell disease, circulatory stasis, acidosis, and hypoxemia induce red cell deoxygenation and consequent sickling. Tourniquets are an important adjunct in limb surgery to obtain a bloodless field. Many local and systemic effects, due to the inflation and deflation of the tourniquet, can develop. These effects may have severe consequences if comorbidities are present. The use of a tourniquet in sickle cell patients is controversial because it may provoke vaso-occlusive complications.
Areas covered: We reviewed the literature to detect reports of the use of tourniquet in sickle cell disease or sickle trait. We found only three case reports and five case series, three of which controlled, none randomized, on the complications of tourniquet.
Expert commentary: From what we could find in the literature and contrary to what is suggested by most guidelines it appears that complications are rare. However, caution must be applied and the risk/ benefit ratio carefully considered
A new record of Caudammina (Foraminiferida) from the upper Rupelian of Madonie Mts. (Sicily)
No full textThe systematic assignment of two populations of Caudammina from deep-water agglutinated foraminifera (DWAF) assemblages from the upper Rupelian of the Madonie Mts. (Benedetti & Pignatti, in press), cropping out near Portella Colla (NW Sicily), is discussed. Biometrical data of diameter of the neck (a), width (b), length (c) and factor b/a (Bubík, 1997; Geroch, 1959; Rögl, 1995) allow us to compare them with other species from the Cretaceous to the Middle Eocene. The ratio c/b is proposed to define the degree of increase in size in the different species.
Two statistical populations of Caudammina from Portella Colla (n=27 and 35) are compared with data for C. ovulum (Grzybowski, 1896), C. gigantea (Geroch, 1960), C. ovuloides
(Grzybowski, 1901), and C. crassa (Geroch, 1966).
The biometrical parameters considered indicate that C. ovulum is smaller and has less pyriform chambers; C. crassa has a thicker neck, whereas C. ovuloides has smaller b/a values.
The populations of Caudammina from Portella Colla represent probably the first record of this genus for the Rupelian, because the last recorded occurrence of C. ovulum and C. ovuloides is referred to the Middle Eocene (Kaminski & Gradstein, 2005).
A significant pattern in the genus is a trend towards increase in size in Late Cretaceous times, up to the extinction of C. gigantea at the K/T boundary. A similar trend, following Cope’s rule, can be hypothesized for the Paleocene-Oligocene, in which the large-sized Caudammina from Portella Colla represent the end members of this evolutionary trend
Paleoecology of the foraminifer Acruliammina longa (Tappan, 1940) from the upper Hauterivian of the Neuquén Basin (northern Patagonia, Argentina)
No full textHerein the epibiont agglutinated placopsilinid foraminifer Acruliammina longa from the upper Hauterivian of the Neuquén Basin is discussed. This is the first record from South America of A. longa, already known from the upper Valanginian to lower Turonian? of North America and Europe. The studied material consists of foraminiferal tests forming macroids and encrusting the valves of Ptychomya koeneni, coming from poorly lithified claystones/siltstones to marlstones forming high frequency (6th-order) depositional sequences within the upper Hauterivian Agua de la Mula Member of the Agrio Formation. This new record extends the paleobiogeographic distribution of A. longa, and allows us to investigate the paleoenvironmental and paleoecological significance of this species in a mixed carbonate and siliciclastic ramp. Energy dispersive spectroscopy and X-ray computed microtomography were used to evaluate taphonomic features of foraminiferal tests, highlighting differences between tests that encrust bivalves and those forming macroids, which also differ in their position within the 3rd-order sedimentary sequences. A. longa tests encrusting bivalves are less damaged, show coarser grain size, and occur throughout the 3rd-order regressive systems tracts, whereas tests forming macroids show higher breakage and finer grain size, occurring throughout the 3rd-order transgressive systems tracts. This distribution allows us to interpret changes in rates of terrigenous input at the time of encrustation, and also in energy conditions, highlighting the opportunistic behavior of A. longa. Low sedimentation rates represent the main paleoenvironmental condition that favored foraminiferal propagule settlement and the growth of A. longa, both on bivalve fragments exposed on the seafloor in the case of macroids, and on living Ptychomya koeneni shells.Fil: Caratelli, Martina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Citton, Paolo. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Archuby, Fernando. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Centro de Estudios Integrales de la Dinamica Exogeno.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pignatti, Johannes. Università degli studi di Roma "La Sapienza"; Itali
Biometric study of Nephrolepidina praemarginata (Douvillé, 1908) from the Madonie Mountains (Sicily)
No full textA wealth of data exists on the evolutionary trends of Oligo-Miocene Nephrolepidina from the Mediterranean area concerning both embryonic and nepionic acceleration (Drooger, 1993). New biometrical data on statistically significant populations of Nephrolepidina are here presented. A succession of the Caltavuturo Formation, near Portella Colla (Madonie Mts., Sicily), contains several breccia layers rich in larger foraminifers (Benedetti & Pignatti, in press). Resedimented Nephrolepidina populations from these levels have been investigated biometrically. A total of 24 parameters have been measured from oriented equatorial sections of megalospheric specimens and 8 factors have been derived from selected parameters.
According to De Mulder (1975), the degree of enclosure of the deuteroconch on the protoconch (factor A) and the number of adauxiliary chambers (parameter C), are sufficient for the recognition of N. praemarginata (Douvillé, 1908). The investigated samples can be referred to chronobiozone SBZ22A of Cahuzac & Poignant (1997) (Upper Rupelian) basing on the first occurrence of N. praemarginata and Eulepidina formosoides. The recognition of the expected trends trough time of increase in embryo size, degree of enclosure of the protoconch by the deuteroconch and average number of adauxiliary chambers, is hampered by oscillation of mean values.
Factor dII/dI versus parameter C evidences a more definite positive trend compared with other measures; on the contrary the mean values of protoconch size for each population show an inverse trend especially for the younger samples. This is interpreted as a consequence of resedimented tests from progressively deeper environments; protoconch size decrease is expected for populations far from the ecological optimum, according to the biometrical investigations on recent nummulitids (Pécheux, 1995)
“Taberina” bingistani Henson, 1948 (Foraminifera) from the upper Cenomanian of Apulia (Southern Italy): a new record.
No full textThe first occurrence of “Taberina” bingistani Henson, 1948 from Upper Cenomanian limestones of the Apulian platform cropping out near Polignano a Mare is recorded. The stratigraphic and paleogeographic range of this species, whose generic assignment is still doubtful, are discussed
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