142 research outputs found
Service offshoring in India: general and country specific factors affecting the entry mode
No full textThe 2.5-dimensional turbulence in shear-thinning jets
No full textThe dimensional transition in turbulent jets of a shear-thinning fluid is studied via direct numerical simulations. Our findings reveal that under vertical confinement, the flow exhibits a unique mixed-dimensional (or 2.5-dimensional) state, where large-scale two-dimensional and small-scale three-dimensional structures coexist. This transition from three-dimensional turbulence near the inlet to two-dimensional dynamics downstream is dictated by the level of confinement: weak confinement guarantees turbulence to remain three-dimensional, whereas strong confinement forces the transition to two dimensions; the mixed-dimensional state is observed for moderate confinement and it emerges as soon as flow scales are larger than the vertical length. In this scenario, we observed that the mixed-dimensional state is an overall more energetic state, and it shows a multi-cascade process, where the direct cascade of energy at small scales and the direct cascade of enstrophy at large scales coexist. The results provide insights into the complex dynamics of confined turbulent flows, relevant in both natural and industrial settings
The role of urodynamics in the management of female stress urinary incontinence
No full textAIM:
The role of urodynamic study (UDS) in the management of female stress urinary incontinence (SUI) is one of the most controversial and debated topic in urogynecology. Here, we aimed to systematically assess the most relevant available evidence on urodynamics' value in the management of women with stress urinary incontinence.
METHODS:
A systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement was performed in May 2018. Only randomized clinical trials, prospective studies, or retrospective studies articles evaluating the use of urodynamic studies in women with stress urinary incontinence were included.
RESULTS:
After screening a total of 3055 records, 39 studies published from 1996 to 2018 were included.
CONCLUSIONS:
In an uncomplicated population of women with SUI, it is not demonstrated that preoperative urodynamic evaluation can improve the outcome of continence surgery; however, UDS provides additional information regarding lower urinary tract function that could guide the physician to make the right therapeutic choice. UDS should be considered mandatory before surgery in complicated patients, but its use should also be evaluated in index patients when the results may help counseling and management of these women
U/Th dating of a Cladocora caespitosa from Capo S. Marco marine Quaternary deposits (Sardinia, Italy)
No full text""A whole specimen, not reworked and well preserved of Cladocora caespitosa has been found within the marine Quaternary. deposits, outcropping along the eastern coast of the Capo San Marco Promontory. The U\\\/Th dating of this sample has provided a minimum. age of 70 ± 4 ka B.P. This dating allows to state that these marine deposits, containing the coral, are not Holocene in age."
Holocene aggradation/erosion of a tufa dam at Triponzo (central Italy.)
No full textThe 14C dating of organic-rich layers from the backfill sequences of the Triponzo village tufa dam (Tiber River basin) allows us to outline the Holocene aggradation/erosion stages of fluvial tufa in Central Italy. Here,
the deposition of tufa first occurred prior to 8240 ± 75 14C yr BP (7480-
7070 cal bC) and continued, even if with different rates, giving rise to a lacustrine/swampy basin upstream. Since 3760 ± 60 14C yr BP (2350-2010 cal bC) a sequence of alternating periods of dam erosion and aggradation occurred. After 2825 ± 60 14C yr BP (1160-830 cal bC) fluvial incision eventually cut the dam down to the present valley bottom, being only interrupted
by a short-lived phase of dam aggradation which caused the
formation of a strath terraces covered with gravels and tufa sands. A comparable evolution pattern is shown by other tufa dams in Central Italy. This paper deals with the control factors of tufa deposition/erosion during the Holocene with a particular reference to the role of climate changes
The Montirone Travertine mound:a multidiscilinarity approach and hydro-structural geological implications for Euganean Geothermal Field (EGF)
No full textThe Montirone Travertine mound:a multidiscilinarity approach and hydro-structural geological implications for Euganean Geothermal Field (EGF)
No full textThe Montirone is a travertine-made hill (max. height 15.75 m a.s.l.)
located in the Abano Terme area of the Euganean Geothermal Field (EGF),
that extends on a plain band of 36 Km2 south of Padova (Veneto-Italy).
The existence of an extensional relay zone, buried hundred meters
beneath the alluvial cover, between segments of the Schio-Vicenza fault
system (SVFS) has been proposed. This structure accommodates a local
extensional regime that keeps open fractures in the subsurface of EGF and
enhances the uprising of hot waters. The temperature of thermal waters,
used mainly for spa, ranges from 60°C to 86°C. 3H and 14C
measurements suggest a residence time greater than 60 years, probably a
few thousand years. At present, about 250 wells are active and the total
average flow rate of exploited thermal fluids is 15 Mm3/Y.
Until the 1960, the only natural occurrence of thermal waters in Abano
was located on the Montirone hill; hot waters fed several pools located on
the flat top and at the base of the hill and were partially channeled to
move a mill-wheel. The intense exploitation of thermal waters, linked to
the increasing number of thermal wells, lowered the potentiometric level
from more than 16 m a.s.l. to -15 m a.s.l. (year 1982; at present is 5 m
a.s.l.) and dried up the hot springs. The hill has a sub-circular shape,
covers an area of 10000 m2 and can be classified as a regular shaped
travertine mound.
The mound is affected by a network of fractures mainly composed of two
sets (WNW-ESE and NNE-SSW) that can be interpreted as a fracture mesh
developed in a dilational stepover between strike-slip or transtensional
fault segments of the SVFS. The trend of fissures parallels the trend of the
main regional structural elements (e.g. SVFS; mainly oriented NW-SE)
and is consistent with the direction of the anisotropy depicted in the
variogram analysis of transmissivity calculated in the bedrock of EGF
(N110°E).
Two drillings (about 1m deep) were made to study the depositional facies
of the travertine because of the absence of relevant cross sections. Thin sections of the core samples show the dominance of layered travertine
made of lime-mudstone with paper-thin rafts and laminae of bacterial
shrub, locally covered by crystalline crusts made of feather-like calcite.
Moreover, soft sediment syndepositional deformations and repeated
phases of karstic dissolution and redeposition have been observed.
Isotopic analyses on uranium-series, carried out on crystalline crusts
sampled during the drillings, have given ages from 30±4 kY to 25±5 kY.
Moreover, the low content of U (from 3 to 12 ppb) and the high activity
ratio of 234U/238U (>2) clarify the high interaction between rock and
water, typical of a deep geothermal system with high residence time of
waters.
Geophysical methods, and particularly Electromagnetic survey (EM) and
Electrical Resistivity Tomography (ERT) were used to determine the
mound geometry. The map of EM measurements (depth of investigation
around 1.5m) shows the presence of two resistive areas along the slope
and a more conductive region on the top of the mound. The latter can be
interpreted as indicative of the uprising of thermal waters through a more
fractured zone. ERT surveys confirm the vertical extent of the conductive
and resistive anomalies, and support the interpretation above.
The presence of the Montirone travertine deposit strongly supports the
existence of a releasing structure in the subsurface, which controls the
development of the EGF, and an ongoing activity of the SVFS, which is
generally considered inactive. The analysis on U-series isotopes gives
another important constraint on the deep circulation and a long residence
time of thermal waters
A multidisciplinary approach to understanding carbonate deposition under tectonically controlled hydrothermal circulation: A case study from a recent travertine mound in the Euganean Hydrothermal System, northern Italy
No full textA multidisciplinary study was carried out on an Upper Pleistocene travertine mound (Montirone Hill; Abano Terme, south of Padova, Veneto, Italy) with the aim of developing a comprehensive understanding of the processes interacting in structurally controlled thermal springs and the consequent deposition of thermal limestones. The sedimentology, geochemistry, structural characteristics and
hydrogeology of the mound, which is associated with the Euganean geothermal field
and the related complex structural framework of the Schio-Vicenza fault system,
were investigated. A palaeo-environmental model of the deposit has been
reconstructed clarifying the connection between the travertine deposition and the
regional structural setting. Calcium-rich thermal waters rose from spring orifices
(estimated temperature from 54°C to 61°C based on geochemical calculations) and
produced a mound made of coalescent shield-like bodies. The dominant limemudstone facies resulted from the accumulation of lime mud at the bottom of shallow crater-like basins located on top of stacked cones. Soft sediment deformations affecting the lime mud sediment were most likely produced by the recurrent uprising of gas bubbles. The overlying crystalline crusts were deposited on the flanks of the mound by waters overflowing from the vents with laminar flux. A deep hydrothermal circuit with a long period of water–rock interaction is supported by geochemical analyses. Furthermore, a local extensional regime, enhancing the migration of thermal fluids to the surface, is inferred based on the results of the structural analysis carried out on the fault/fracture mesh that affects the mound. These results corroborate the well-established relation among travertine deposits, hydrothermal systems and fault systems and substantiate the structurally controlled conceptual model of the Euganean hydrothermal system, suggesting that both the thermal and the fault systems were active at least since 34 ka
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