376 research outputs found
Bioerosion by microbial euendoliths in benthic foraminifera from heavy metal-polluted coastal environments of Portovesme (South-Western Sardinia, Italy)
A monitoring survey of the coastal area facing the industrial area of Portoscuso-Portovesme (south-western Sardinia, Italy) revealed intense bioerosional processes. Benthic foraminifera collected at the same depth (about 2 m)but at different distances from the pollution source show extensive microbial infestation, anomalous Mg/Ca molar ratios and high levels of heavy metals in the shell associated with a decrease in foraminifera richness, population density and biodiversity with the presence of morphologically abnormal specimens. We found that carbonate dissolution induced by euendoliths is selective, depending on the Mg content and morpho-structural types of foraminiferal taxa. This study provides evidences for a connection between heavy metal dispersion, decrease in pH of the sea-water and bioerosional processes on foraminifera
Discrimination between effects induced by microbial activity and water-rock interactions under hydrothermal conditions according to REE behaviour
Rare earth elements (REE) were investigated in siliceous stromatolites forming in the Specchio di Venere Lake on Pantelleria Island. Chondrite-normalised patterns show significant La enrichments and Eu depletions suggesting that fluids involved in stromatolite growth experienced strong rock-water interactions under hydrothermal conditions. At the same time, enrichments in heavy REE (HREE) with respect to intermediate REE (MREE) suggest that hydrothermal fluids interacted with microbial mats during deposition of the stromatolites. The above-mentioned features suggest that rock-water interactions and bacterial activity were simultaneously recorded in the REE patterns of stromatolites, and can be discriminated in terms of amplitudes of the La anomaly, and the HREE/MREE ratio
Fossichnus solus and Oichnus simplex, two peculiar ichnospecies in modern benthic foraminifera from a polluted area in SW coast of Sardinia, Italy
The modern benthic foraminiferal tests collected from a coastal area of south-western Sardinia (Portoscuso-Portovesme) that is heavily polluted by industrial activity reveal intense and widespread bioerosional structures induced by diversifi ed microborers. A large number of the foraminifera reveals microscopic round holes (1-60 ÎĽm in diameter) and roundish concavities (25x40 ÎĽm in external diameter) on their surface that belong, respectively, to the ichnospecies Oichnus simplex Bromley, 1981, and Fossichnus solus Nielsen et al., 2003. These traces just occur in the tests of the foraminifera which are heavily infested by microendolithic cyanobacteria, algae and fungi suggests comparable ethological behaviour between the ichnospecies Fossichnus and Oichnus and the microbial euendoliths that are ascribed to individual biological taxa. The greater occurrence of F. solus and O. simplex in the high-Mg foraminiferal porcelanaceous tests than in the low-Mg foraminiferal hyaline tests reveals that the bioerosional processes seem to be related to the Mg/Ca ratio, as well as to morphological structures of the taxa
Accumulation of rare earth elements in common vine leaves is achieved through extraction from soil and transport in the xylem sap
Rare Earth Elements play a critical role in current clean technologies but face scarcity and environmental challenges in their extraction. Using semi-natural controlled experiments, we tested the ability of V. vinifera L. to accumulate Rare Earth Elements naturally present in the soil. We demonstrate that V. vinifera L. passively transports all Rare Earth Elements from soil to leaves via Xylem-sap mirroring soil conditions. Since this process starts from the fifth month of V. vinifera L. growth without damaging the crops, we. estimate that it is possible to recover 900 milligrams of Rare Earth Elements per hectares from vineyard without harvesting the whole plant. We propose the direct extraction of Rare Earth Elements from leaves overcoming unstainable biomass burning yielding environmental and economic benefits.The pathway for the accumulation of rare earth elements in Vitis vinifera L. leaves is extraction from vineyard soils and subsequent transport in the xylem sap, suggests a semi-natural controlled experiment
Trace elements release from volcanic ashes to seawater. Natural concentrations in Central Mediterranean sea.
Distributions and concentrations of many minor and trace elements in epicontinental basins, as Mediterranean Sea,
are mainly driven to atmospheric fallout from surroundings. This mechanism supplies an estimated yearly flux of
about 1000 kg km-2 of terrigenous matter of different nature on the whole Mediterranean basin. Dissolution of
these materials and processes occurring at solid-liquid interface along the water column drive the distributions of
many trace elements as V, Cr, Mn, Co, Cu, and Pb with contents ranging from pmol l-1 (Co, Cd, Pb) to nmol l-1
scale in Mediterranean seawater, with some local differences in the basin.
The unwinding of an oceanographic cruise in the coastal waters of Ionian Sea during the Etna’s eruptive activity
in summer 2001 led to the almost unique chance to test the effects of large delivery of volcanic ash to a coastal sea
water system through the analyses of distribution of selected trace elements along several seawater columns. The
collection of these waters and their analyses about V, Cr, Mn, Co, Cu, and Pb contents evidenced trace element
concentrations were always higher (about 1 order of magnitude at least) than those measured concentrations in
the recent past in Mediterranean seawater, apart from Pb. Progressive increase of concentrations of some elements
with depth, sometimes changing in a “conservative” behaviour without any clear reason and the observed higher
concentrations required an investigation about interaction processes occurring at solid-liquid interface between
volcanic ash and seawater along water columns.
This investigation involving kinetic evaluation of trace element leaching to seawater, was carried out during a
6 months time period under laboratory conditions. X-ray investigations, SEM-EDS observations and analyses
on freshly-erupted volcanic ash evidenced formation of alteration clay minerals onto glass fraction surfaces.
Chemical analyses carried out on coexisting liquid phase demonstrated that trace element leaching occurs through
a first quick followed by a slow second step that attaints to an apparent equilibrium after 6 months. Amplitude of
kinetic rate constant measured for SiO2 release during the first step and behaviour of Ti/Si and Cr/Si rations in
primary volcanic minerals, glass fraction and leaching solutions during the first 1 month stage of the experimental
interaction allowed to demonstrate that trace element release mainly occurs from glassy materials and Ti-rich
magnetite
Meta-review of systematic and meta-analytic reviews on family psychoeducation for schizophrenia
The purpose of family psychoeducation is to increase patients’ and their families’ knowledge and understanding of their illness and treatment. Improved knowledge of schizophrenia is expected to enable people to cope better with their illness. The aim of this review is to summarize and appraise evidence from published systematic and meta-analytic reviews on family psychoeducation in schizophrenia. Thorough search and analysis of reviews on efficacy of family psychoeducation in schizophrenia were carried out in PubMed/Medline (19872015), Ovid/Psych Info (1987-2015), and the Cochrane Database of Systematic Reviews. We included only reviews reporting quantitative summary statistics on studies carried out in patients with schizophrenia and written in English. Review methodology was assessed using the Assessment of Multiple Systematic Reviews (AMSTAR) checklist. Double check by two independent assessors was applied. Nine reviews meeting inclusion/exclusion criteria were included in the meta-review. Risk of relapse was reduced in protocols that included family members, whether conducted in single family or in multifamily group sessions. However, effectiveness seems not to be maintained at follow-up. Hospital admission/re-hospitalization was less influenced by family psychoeducation, and no reproducible effect on compliance/medication adherence was found. Overall, quality of evidence on the effectiveness of family psychoeducation in schizophrenia is poo
Geochemistry of REE, Zr and Hf in a wide range of pH and water composition: The Nevado del Ruiz volcano-hydrothermal system (Colombia)
The geochemical behaviour of Rare Earth Elements, Zr and Hf was investigated in the thermal waters of Nevado del Ruiz volcano system. A wide range of pH, between 1.0 and 8.8, characterizes these fluids. The acidicwaters are sulphate dominatedwith different Cl/SO4 ratios. The important role of the pH and the ionic complexes for the distribution of REE, Zr and Hf in the aqueous phase was evidenced. The pH rules the precipitation of authigenic Fe and Al oxyhydroxides producing changes in REE, Zr, Hf amounts and strong anomalies of Cerium. The precipitation of alunite and jarosite removes LREE from the solution, changing the REE distribution in acidic waters. Y-Ho and Zr-Hf (twin pairs) have a different behaviour in strong acidic waterswith respect to the water with pH near-neutral. Yttrium and Ho behave as Zr and Hf in waters with pH near neutral-to-neutral, showing superchondritic ratios. The twin pairs showed to be sensitive to the co-precipitation and/or adsorption onto the surface of authigenic particulate (Fe-, Al-oxyhydroxides), suggesting an enhanced scavenging of Ho and Hf with respect to Y and Zr, leading to superchondritic values. In acidic waters, a different behaviour of twin pairs occurs with chondritic Y/Ho ratios and sub-chondritic Zr/Hf ratios. For the first time, Zr and Hf were investigated in natural acidic fluids to understand the behaviour of these elements in extreme acidic conditions and different major anion chemistry. Zr/Hf molar ratio changes from 4.75 to 49.29 in water with pH < 3.6. In strong acidic waters the fractionation of Zr and Hf was recognized as function of major anion contents (Cl and SO4), suggesting the formation of complexes leading to sub-chondritic Zr/Hf molar ratios
On the tilt of the Earth's polar axis (climat): Some 'impressionist' remarks
In this lengthy letter, we wanted to discuss the concept of climate based on
definitions established for over a century and direct observations that we have
been collecting for more than a century as well. To do this, we present and
discuss the remarkably stable maps over time of the various physical parameters
that make up the climate corpus: solar temperature, atmospheric pressure,
winds, precipitation, temperature anomalies. This impressionistic tableau that
we are gradually sketching as our reflection unfolds leads us to the following
proposition: What if, as Laplace first proposed in 1799 and later
Milankovi\{'}c in 1920, ground temperature were merely a consequence of climate
and not a separate parameter of climate in its own right?Comment: 24 pages, 11 Figure
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