Search results for " Turnover"

The role of mitochondrial oxidative stress in aging.

2003

Mitochondria are both a major source of oxidants and a target for their damaging effects, and, therefore, mitochondrial oxidative stress appears to be a cause, rather than a consequence, of cell aging. Oxidative damage in aging is particularly high in specific molecular targets, such as mitochondrial DNA and aconitase, and mitochondrial oxidative stress may drive tissue aging through intrinsic apoptosis. Mitochondrial function and morphology are impaired upon aging, as judged by a decline in membrane potential as well as by an increase in peroxide production and size of the organelles. In view of the age-related decreases in mitochondrial protein synthesis, mitochondrial transcripts, and ex…

Humic substances along the profile of two Typic Haploxerert.

2002

In Vertisols, organic matter contributes to soil colour by formation of organo-mineral complexes and affects morphological, physico-chemical, biological and biochemical properties. Turbation may affect the chemical and structural composition of the most stabilised fractions of soil organic matter (SOM), i.e., humic substances (HS). The objectives of this study were to: (1) characterise SOM in two Vertisols (V1 and V2) developed under Mediterranean climate in Italy, using some HS characteristics as indicators of SOM turnover in Vertisols, and (2) explore possible differences related to the pedomorphologic conditions of the area under which two soils have formed. SOM evolution along the soil …

An “Uncertainty Principle” for the Mediterranean annual dry grasslands

2009

Preliminary results of diachronic researches on the spatial arrangement and species richness in Mediterranean annual dry grasslands (Tuberarietea guttatae) demonstrated that the patchiness resulted minimized and the temporal stability maximized at elevations offering the best compromise between the summer drought stress and the winter cold stress. Moreover, the temporal stability of the Mediterranean annul dry grasslands could not necessarily be related with their demographic inertia, meaning that the turnover and rearrangement of species within the community do not necessarily implicate significant changes in the average species composition over time. On the other hand, the survival chance…

Effects of temperatures on the spatial arrangement in Mediterranean annual dry grasslands

2009

Some preliminary results of diachronic researches on the spatial arrangement and species richness in Mediterranean annual dry grasslands belonging to the class Tuberarietea guttatae are presented. Our results are based on 12 permanent plots, set in three places at different heights in Southern and Central Sardinia. Sites were chosen to have annual species richness and plant density not significantly different. The relationship between patchiness and temporal stability was investigated at the scale of the square plots. We used the mean abundance divided by the SD in abundance (S = xm/r), as the measure of temporal stability of populations (Tilman 1999) and the Shannon-Wiener index to evaluat…

Le Faune a Mammiferi della Sicilia tra il Tardoglaciale e l'Olocene

2008

Le faune a mammiferi della Sicilia tra il Tardoglaciale e l’Olocene

2011

A check-list of Sicilian terrestrial mammals from Late Glacial to the Holocene has been compiled and a quantitative methodology of data analysis to calculate their occurrence and extinction rates has been adopted, in order to synthesize the temporal turnover of mammal species occurred during the last 17,5 ky. In such interval Sicily, probably passed from a fully connection (via a temporary land bridge generated by eustatic change of sea level) with Southern Calabria to the present isolation phase. To better focus the faunal turnover, this temporal interval has been subdivided into three phases: Late Glacial, ancient and recent Holocene. 28 Mammal taxa were recorded: 17 in the Late Glacial, …

Bisphosphonate-associated femoral fracture: implication for management

2008

Studies carried out on individuals being treated long term with bisphosphonates have provoked considerable interest and perplexity about the effect that these drugs have on bone turnover in the long run. In fact the experiences reported by numerous researchers tend to highlight how treatment with high doses of bisphosphonates over many years, of individuals with osteoporosis complicated by or secondary to neoplastic pathologies, causes a suppression of bone turnover that over time predisposes the bone to the accumulation of micro damage that can then result in complicated fractures, as in the case described here.

Turnover and availability of soil organic carbon under different Mediterranean land-uses as estimated by 13C natural abundance

2013

Summary Soil organic matter (SOM) is an important factor in ecosystem stability and productivity. This is especially the case for Mediterranean soils suffering from the impact of humans and degradation as well as harsh climatic conditions. We used the carbon (C) exchange resulting from C3-C4 and C4-C3 vegetation change under field conditions combined with incubations under controlled conditions to evaluate the turnover and availability of soil organic C under different land-uses. The 40-year succession of Hyparrenia hirta L. (C4 photosynthesis) after more than 85 years of olive (Olea europaea L.) tree (C3 photosynthesis) growth led to the exchange of 54% of soil organic C from C3 to C4 form…

TREATMENT WITH DAILY SUBCUTANEOUS TERIPARATIDE (1-34) COMPARED WITH DAILY SUBCUTANEOUS PARATHYROID HORMONE (1-84) IN WOMEN WITH SEVERE POSTMENOPAUSAL…

2008

Genome wide studies of mRNA synthesis and degradation in eukaryotes

2012

In recent years, the use of genome-wide technologies has revolutionized the study of eukaryotic transcription producing results for thousands of genes at every step of mRNA life. The statistical analyses of the results for a single condition, different conditions, different transcription stages, or even between different techniques, is outlining a totally new landscape of the eukaryotic transcription process. Although most studies have been conducted in the yeast Saccharomyces cerevisiae as a model cell, others have also focused on higher eukaryotes, which can also be comparatively analyzed. The picture which emerges is that transcription is a more variable process than initially suspected,…