Search results for "surface"
showing 10 items of 9345 documents
Video display terminal use and dry eye: preventive measures and future perspectives
2022
Background: Dry eye disease (DED) is a common cause of ocular pain and discomfort. Dry eye disease (DED) stems from a loss-of-tear film homeostasis and is frequently seen in video display terminal (VDT) users. Video display terminal (VDT) use reduces blink rates and increases incomplete blinks, leading to tear film instability and ocular inflammation, promoting DED. Purpose: To assess and evaluate the methods for preventing VDT-associated DED and ocular discomfort. Methods: Studies were found using PubMed and Embase with the search terms: (digital visual terminal* OR computer use OR screen use OR smartphone OR display OR visual display terminal* OR computer vision syndrome OR tablet OR phon…
The closure of Pak1-dependent macropinosomes requires the phosphorylation of CtBP1/BARS
2007
Membrane fission is an essential process in membrane trafficking and other cellular functions. While many fissioning and trafficking steps are mediated by the large GTPase dynamin, some fission events are dynamin independent and involve C-terminal-binding protein-1/brefeldinA-ADP ribosylated substrate (CtBP1/BARS). To gain an insight into the molecular mechanisms of CtBP1/BARS in fission, we have studied the role of this protein in macropinocytosis, a dynamin-independent endocytic pathway that can be synchronously activated by growth factors. Here, we show that upon activation of the epidermal growth factor receptor, CtBP1/BARS is (a) translocated to the macropinocytic cup and its surroundi…
Geomorphological, chemical and physical study of “calanchi” landforms in NW Sicily (southern Italy)
2012
Abstract This work deals with an integrated geomorphological and chemical–physical study of “calanchi” landforms in two sites (Ottosalme and Catalfimo) of NW Sicily (southern Italy), developed on dominant silty-clay deposits. The calanchi fronts are characterized by different morphological features and dominant geomorphic processes. Sharp knife-edged ridges and concentrated water runoff dominate at Ottosalme, and smoother landforms affected by mass movements (mud flows and translational slides) prevail at Catalfimo. We focused on some geochemical and physical parameters such as pH , total dissolved salts, sodium adsorption ratio ( SAR ), porosity, plastic and liquid limits as possible cause…
Climate signatures on decadal to interdecadal time scales as obtained from mollusk shells (Arctica islandica) from Iceland
2013
Abstract Pronounced decadal climate oscillations are detected in a multi-centennial record based on shell growth rates of the marine bivalve mollusk, Arctica islandica, from Iceland. The corresponding analysis of patterns in sea level pressure and temperature exhibit large-scale teleconnections with North Atlantic climate quantities. We find that the record projects onto blocking situations in the northern North Atlantic. The associated circulation shows a low-pressure signature over Greenland and the Labrador Sea and a high-pressure system over Western Europe associated with northeasterly flow towards Iceland and weakening in the westerly zonal flow over Europe. It can be speculated that s…
Dendropoma lower intertidal reef formations and their palaeoclimatological significance, NW Sicily
1999
Abstract Most carbonate rocky shores of NW Sicily are marked by a coalescence of shells of the gastropod Dendropoma in a construction that is variably developed as a response to wave impact. Here, we review all the available information on these constructions and find that the fossil reefs are reliable sea-level indicators. The thickness of the reef samples never exceeds 30–40 cm below sea-level, whereas all 14 C dates fall within a range of few centuries. Some small fragments ejected by violent sea storms date back to 2500 years cal BP. No samples older than 6200 years cal BP have been detected so far. The present distribution of Mediterranean vermetid platforms should result from a northw…
Geoarchaeological evidence of marshland destruction in the area of Rungholt, present-day Wadden Sea around Hallig Südfall (North Frisia, Germany), by…
2018
Abstract Geophysical and geoarchaeological investigations were carried out in the Wadden Sea of North Frisia (Schleswig-Holstein, Germany) to elucidate major environmental changes that considerably altered the coastal landscape since medieval times. Between the 12 th and 14 th cent. AD, the present-day tidal flats around the marsh island Hallig Sudfall belonged to the historical Edomsharde district and its main settlement Rungholt . For North Frisia, it is well known that during medieval and early modern times, extreme storm surges caused major land losses associated with a massive landward shift of the coastline. Today, cultural traces like remains of dikes, drainage ditches, terps or even…
Quaternary development and evolution of the sedimentary environments in the Central Mediterranean Spanish coast
1995
Abstract The reconstruction of the evolutive phases of the Mediterranean Spanish Central sector during the Late Quaternary is the aim of this work. From geomorphological, sedimentological and chronometrical studies, different morphostratigraphic units are determined. Results point out the development of several transgressive phases. The older one go back to isotope stage 7. The Eemian transgression is broadly recorded, and its coastline was near the present one. During the Flandrian episode, the sea surpassed the current coastline in the northern coastal plain, while in the meridional littoral erosive notches were formed between +1 and +2 m. During the regressive events, we find the prograd…
Yttrium and REE signature recognized in Central Mediterranean Sea (ODP Site 963) during the MIS 6–MIS 5 transition
2010
Abstract The Mediterranean Sea acts as a miniature ocean with the development of its own conveyor belt. It constitutes an ideal location to study and forecast how the marine environment responds to rapid climatic change. Here we present a palaeoenvironmental study carried out on the sediments of ODP Site 963, recovered in the Sicily Channel, the sill which divides the western from the eastern Mediterranean basin. We focused on the transition between the penultimate glacial (MIS 6) and the last interglacial (MIS 5), between approximately 130 and 115 kyr BP. A novel approach is proposed, taking into account centennial-scale geochemical data on major elements, selected trace elements, and yttr…
Archaean and Palaeoproterozoic gneisses reworked during a Neoproterozoic (Pan-African) high-grade event in the Mozambique belt of East Africa: Struct…
2006
Abstract This study presents new zircon ages and Sm–Nd whole-rock isotopic compositions for high-grade gneisses from the Udzungwa Mountain area in the central part of the Mozambique belt, Tanzania. The study area comprises a succession of layered granulite-facies para- and orthogneisses, mostly retrograded to amphibolite-facies. The original intrusive contacts became obscured or severely modified during non-coaxial ductile deformation, and extensive shearing occurred during retrogression. Structures reflecting the early deformational history were mostly obscured when the rocks were transported into the lower crust as documented by severe flattening. Only the fragmented gneisses in the easte…
Single zircon ages for felsic to intermediate rocks from the Pietersburg and Giyani greenstone belts and bordering granitoid orthogneisses, northern …
2000
Abstract Previous models for the temporal evolution of greenstone belts and surrounding granitoid gneisses in the northern Kaapvaal Craton can be revised on the basis of new single zircon ages, obtained by conventional UPb dating and PbPb evaporation. In the Pietersburg greenstone belt, zircons from a metaquartz porphyry of the Ysterberg Formation yielded an age of 2949.7±0.2 Ma, while a granite intruding the greenstones, and deformed together with them, has an age of 2853 + 19/−18 Ma. These data show felsic volcanism in this belt to have been coeval with felsic volcanism in the Murchison belt farther east, and the date of ∼2853 Ma provides an older age limit for deformation in the region…