1,721,023 research outputs found
Incidence of ulnar neuropathy at the elbow in the province of Siena (Italy)
No full textBackground: Although ulnar neuropathy at the elbow (UNE) is the second most frequent focal peripheral neuropathy of the upper limb after carpal tunnel syndrome (CTS), no figures on its prevalence or incidence in the general population have been reported. Objective: To determine the incidence of UNE in a general population. Methods: Retrospective study to identify newly diagnosed cases on the basis of clinical symptoms or signs and slowing of motor conduction velocity of the ulnar nerve across the elbow or surgical evidence of nerve compression in the elbow region. Results: In the 5-year period from 1995 to 1999, cases among residents in Siena Province (Italy) were identified from medical records of electromyographic services of Local Health District no. 7 and from hospital medical records coded ICD 354.2, 04.49 and 04.6. Siena province has a population of 251,930. In the 5-year period, 311 cases (112 women and 199 men, mean age 56 years, range 15-86) were identified. The mean annual crude incidence was 24.7 cases per 100,000 person-years, and the standardized incidence was 20.9. The sex-specific incidences were 32.7 for men and 17.2 for women. The mean annual crude and sex-specific incidences remained constant during the study period. The age-specific incidences of whole population and both genders showed an increasing trend with decade of age. The incidence of "possible", "probable" and "definite" UNE cases, classified according to level of motor conduction velocity anomalies and evidence of surgical compression of the ulnar nerve at the elbow, was 4.3, 10.6, and 9.8, respectively. The residents of a health subdistrict where manual work is dominant had a higher male-specific incidence (57.1) than other areas. Conclusions: This is the first published study on the incidence of UNE. The incidence was higher in males than females and about one-thirteenth that reported for CTS in part of the present geographic area. © 2005 Elsevier B.V. All rights reserved
A study on phosphorus flux from sediment in a shallow homogeneous lake
No full textA study on phosphorus release dynamics was conducted into a shallow homogeneus and mesotrophic lake. The purpose was to investigate physical- chemical factors which contribute to the nutrient release-adsorption from sediments. Water and sediment samples were analyzed under different conditions: aerobic and anoxic, static
and mixed. Results in both last cases (anoxic/aerobic conditions) show that the nutrient release- sorption dynamics are strictly linked to the iron- manganese
associated phosphorus contents within the sediments but the low overall phosphorus release is largely linked to the sediment’s calcareous nature (phosphorus precipitation
as hydroxyapatite and co-precipitation/adsorption with carbonates). In the mixed tests cases, as expected, the release is higher compared to static aerobic ones: the
sediments re-suspension allows for a higher contact surface area with water leading to a higher phosphorus desorption. In case of shallow lake the wind can therefore play an important role in influencing phosphorus balance in the waters. This aspect can be even more important when suspended fine clay particles are involved since they can be
considered a support for phosphorus forms. It follows that surficial sediments when re-suspended play a double role: they can redistribute phosphorus along the water column but they can re-adsorb it
Amino acids in surface sediments of the Zannone Island shelf (Western Mediterranean Sea): Possible bioindicators of submarine hydrothermal activity
No full textThis study shows results from amino acid analysis of seafloor sediment sampled between ~80 and ~130 m depth, within an active hydrothermal field located off Zannone Island (Tyrrhenian Sea). The total hydrolysable amino acid (THAA) content was determined at eight stations, three located within the main hydrothermal depression (i.e. the Zannone Giant Pockmark, ZGP) and five located in the surrounding seafloor. THAA concentration ranged between ~2 and ~11 nmol mg−1 dw and the lowest THAA concentrations were found at stations located within the ZGP. Amino acids resistant to degradation or originating from bacteria (β-alanine, histidine, leucine, arginine and lysine) had higher relative abundances inside the ZGP, whereas amino acids susceptible to degradation or originating from cellular plasma (proline, phenylalanine and tyrosine) showed higher relative abundances outside the ZGP. Degradation and reactivity indices were calculated, and the sedimentary organic matter in the three outside ZGP stations B07, B08 and B09 was found to be the most labile and reactive. Together with THAA concentrations, sediment grain size and carbon percentages were measured at 12 stations, five located within the ZGP and seven located outside the ZGP. At all stations, the percentage of sand was ~75% or higher. Carbon percentages were lower in samples located inside the ZGP than in the surrounding stations. The southern outside ZGP station B12 was found to be similar in terms of amino acids composition to the three inside ZGP stations, suggesting the influence of the hydrothermal fluids at this station
A general theory for the effect of local topographic unevenness on contourite deposition around marine capes. An inverse problem applied to the Italian continental margin (Cape Suvero)
No full textThe interaction between ocean bottom currents and topographic obstacles often results in sedimentary processes that form intriguing sedimentary deposits. However, without a thorough knowledge of both fluid mechanical processes and oceanographic settings regarding these sedimentary deposits, such an inherited interaction is not easy to understand. We here analyze the interaction between a bottom, geostrophic current and a local topographic depression, a slide scar offshore Cape Suvero, an Italian headland in the southern Tyrrhenian Sea, in order to explain the presence of contourite drifts off this cape. We apply the classical conservation of marine water potential vorticity and demonstrate the presence of a steady cyclonic circulation over the scar, which in turn affects contourite deposition. We thus show that the application of the potential vorticity conservation provides a simple but powerful, general tool for the understanding of the complex relations among ocean current, seafloor morphologies and sedimentary structures. (C) 2016 Elsevier B.V. All rights reserved
Il mondo di Dickens e la città dei morti
No full textSelezioni e analisi di una scelta di passi dicklensiani relativi ai cimiteri, collocati nel contesto delle leggi del periodo e del contributo dato da Dickens al dibattito sul problema delle condizioni di vita urbane
Environmental factors controlling the distribution of rhodoliths. An integrated study based on seafloor sampling, ROV and side scan sonar data, offshore the W-Pontine Archipelago
No full textThe effects of different environmental factors controlling the distribution of different morphologies, sizes and growth forms of rhodoliths in the western Pontine Archipelago have been studied. The analysis of 231 grab samples has been integrated with 68 remotely operated vehicle (ROV) videos (22 h) and a high resolution ( < 1 m) side scan sonar mosaic of the seafloor surrounding the Archipelago, covering an area of approximately 460km2. Living rhodoliths were collected in approximately 10% of the grab samples and observed in approximately 30% of the ROV dives. The combination of sediment sampling, video surveys and acoustic facies mapping suggested that the presence of rhodoliths can be associated to the dishomogeneous high backscatter sonar facies and high backscatter facies. Both pralines and unattached branches were found to be the most abundant morphological groups (50% and 41% of samples, respectively), whereas boxwork rhodoliths were less common, accounting only for less than 10% of the total number of samples. Pralines and boxwork rhodoliths were almost equally distributed among large (28%), medium (36%) and small sizes (36%). Pralines generally presented a fruticose growth form (49% of pralines) even if pralines with encrusting-warty (36% of pralines) or lumpy (15% of pralines) growth forms were also present. Morphologies, sizes and growth forms vary mainly along the depth gradient. Large rhodoliths with a boxwork morphology are abundant at depth, whereas unattached branches and, in general, rhodoliths with a high protuberance degree are abundant in shallow waters. The exposure to storm waves and bottom currents related to geostrofic circulation could explain the absence of rhodoliths off the eastern side of the three islands forming the Archipelago
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Interaction of down-slope and along-slope processes off Capo Vaticano (southern Tyrrhenian Sea, Italy), with particular reference on contourite-related landslides
No full textThe Late Quaternary architecture of the upper slope-shelf sector of the Calabro-Tyrrhenian continentalmargin off
Capo Vaticano was reconstructed to decipher the interaction of along-slope and down-slope sedimentary
processes, based on the analysis of very high-resolution single-channel seismic profiles and multibeam
bathymetry. Both along-slope bottom currents and downslope gravity processes influenced the stratigraphic
architecture of the margin during the last eustatic cycle, locally forming a mixed turbidite and contourite system.
Along-slope processes formed elongated drifts located on the upper continental slope and outer shelf, while
gravity-driven down-slope processes formed mass-transport deposits and turbidite systems with erosive
channels, locally indenting the present-day shelf. Several slide events affected the elongated drifts and failure
processes appear to be dominated by translational sliding that affect the upper 10–20 m of the stratigraphic
record, with glide plains developed within contourite deposits. The most striking feature is the Capo Vaticano
slide complex, which displays a large spatial coverage (area of about 18 km2), between ca −190 m and
−500 m and is composed of several intersecting slide scars and overlapping deposits. These characteristics are
peculiar for the Tyrrhenian continental margins, where slide events developed in open-slope areas are usually
less complex and smaller in size. This would indicate that high sedimentation rates and occurrence of contourite
deposits can represent a preconditioning factor for medium-large scale slope instability on the Tyrrhenian
margins
Diagnostic analysis of contourite drifts and contour currents around small-scale topographic features: some examples from the Italian Seas (Mediterranean Sea),
No full textWe analyse here contourite drifts presumably related to a topographic control given by promontories or seafloor depressions (e.g., slide scars) in some Italian Seas. We therefore investigate the local effect of a topographic unevenness (such as a landslide scar) on flow contouring a cape by applying the classical conservation of marine water potential vorticity (PV). We further analyse the presence of non-linear and/or baroclinic instabilities that may lead to erosive or depositional conditions which, in turn, inhibit or favour the formation of contourites. Such an analysis is performed by applying the classical theory for conservation of potential vorticity (PV) in a cylindrical frame, which is able to describe the fluid properties by means of bathymetric curvatures
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