902 research outputs found
Analysis of the convergence of the 1/t and Wang-Landau algorithms in the calculation of multidimensional integrals
In this communication, the convergence of the 1/t and Wang - Landau
algorithms in the calculation of multidimensional numerical integrals is
analyzed. Both simulation methods are applied to a wide variety of integrals
without restrictions in one, two and higher dimensions. The errors between the
exact and the calculated values of the integral are obtained and the efficiency
and accuracy of the methods are determined by their dynamical behavior. The
comparison between both methods and the simple sampling Monte Carlo method is
also reported. It is observed that the time dependence of the errors calculated
with 1/t algorithm goes as N^{-1/2} (with N the MC trials) in quantitative
agreement with the simple sampling Monte Carlo method. It is also showed that
the error for the Wang - Landau algorithm saturates in time evidencing the
non-convergence of the methods. The sources for the error are also determined.Comment: 8 pages, 5 figure
The record of the Paleocene-Eocene thermal maximum in the Ager Basin (Central Pyrenees, Spain)
The sedimentary record straddling the Paleocene/Eocene boundary in the Ager Basin (southern Central Pyrenees) was investigated by combining facies analysis, sequence stratigraphy and stable isotope data, within an interval characterized by a great variability of depositional environments. The occurrence of the Paleocene-Eocene Thermal Maximum (PETM) climatic anomaly is tentatively constrained by analogy with its stratigraphic range in the adjacent Tremp-Graus Basin. The main body of the carbon isotope excursion associated with the PETM may be recorded by lacustrine carbonates characterized by a ~ -3‰ shift in d13C with respect to analogous deposits of Thanetian age; a similar shift is recorded between in situ and resedimented pedogenic carbonates, a feature that suggests the partial erosion of the P/E boundary in the Ager Basin
Are fluid inclusions in gypsum reliable paleoenvironmental indicators? An assessment of the evidence from the Messinian evaporites
The paleosalinity of water from which the gypsum precipitated during the Messinian
salinity crisis is a controversial issue. Recent microthermometry studies on primary fluid
inclusions in gypsum provided very low salinity values not compatible with precipitation from
seawater, and suggested strong mixing between seawater and nonmarine waters enriched in
calcium sulfate. We applied a new microthermometric protocol on gypsum crystals from nine
Mediterranean sections that were experimentally stretched to measure a larger population
of fluid inclusions. The results show salinities ranging from 9 to 238 wt‰ NaCl equivalent,
largely falling within the evaporation path of normal seawater. The data from previous studies
were obtained mostly from those fluid inclusions capable of nucleating a stable bubble
after a weak stretching, which probably correspond to those having a lower salinity acquired
through post-depositional crack-and-seal processes. Our data suggest instead that the primary
gypsum precipitated from a marine brine, later modified by post-trapping processes
during tectonics and exhumation
The Messinian "Calcare di Base" (Sicily, Italy) revisited
Three different types of carbonate deposits are included within the "Calcare di Base",commonly envisaged to record the Messinian salinity crisis onset: type 1 consists of sulphur-bearinglimestones, representing the biogenic product of bacterial sulphate reduction after original gypsum;type 2 comprises dm-thick laminated dolomitic limestones interbedded with diatomites, sapropels andmarls found at the top the Tripoli Formation; type 3, the most common variety, consists of m-thickbrecciated limestones interbedded with shales and clastic gypsum.Type 3 shows sedimentary features suggesting a clastic origin and deposition from high- to lowdensitygravity flows; thus, these deposits can be regarded as an end-member of a large variety ofevaporite-bearing gravity flow deposits, with a dominant carbonate component.The genetic and stratigraphic characterization of these carbonates has strong implications for a bettercomprehension of Messinian events; the three types of Calcare di Base seem to have formed duringdifferent stages of the Messinian salinity crisis (MSC). Type 2 formed in the first stage (5.96-5.60 Ma),and is the only type that can be regarded as the Lower Gypsum time-equivalent. Type 3 was depositedin the second stage (5.60-5.55 Ma) and its base is associated with a regional-scale hiatus and erosion(Messinian erosional surface). Type 1 formed even later, likely in post-Messinian time, throughdiagenetic processes affecting resedimented gypsum deposited during the second stage of the MSC.It follows that not all the Calcare di Base deposits record the onset of the Messinian salinity crisis, ascommonly thought. Thus, a detailed facies characterization of these carbonate deposits is fundamental for both stratigraphic reconstructions and a better comprehension of Messinian events
The Interval Kicking Program (IKP) as a Reprogramming Technique for the Soccer Player in an Anterior Cruciate Ligament (ACL) Rehabilitation: A Technical Report
Introduction. We can state as technical-athletic gestural movements that we might call clinical (pivoting, cutting maneuvers, sidestep cuts, changes of direction) associated with ACL injuries. Objective. This technical report was conducted to research methods of reprogramming basic technical skills in the soccer player after anterior cruciate ligament reconstructive surgery. Technical report results. The Interval Kicking Program (IKP) is a model proposed as a neuromotor remodelling of basic gestures and techniques after an ACL injury in soccer player. The teaching progression is ordered regarding the diversified techniques of passing and receiving the ball. The volume, intensity, and progression steps are governed by 1) clinical status (i.e., type of injury, conservative/surgical treatment type, type of sport), 2) performance status, and 3) objective evaluative analysis of periodic follow-ups. The steps provid-ed by the IKP can be 15 and end with the introduction of the player into technical drills with the presence of opponents the first sessions include about 30 minutes of sport-specific, low-intensity exercises, while in the last ones, the volume remains constant, but the intensity and technical complexity of the movements increase. Conclusions. In this technical report, we have highlighted how IKP can be a teaching model for reprogramming basic technical skills in the soccer player after injury. It remains fair to point out how aberrant technical movement partners, side-to-side asymmetries, and postur-al dysfunction are predictive of the risk of compliance and second injury. Further studies and insights are needed to customize the reprogramming of the soccer player’s gestural movements during return to play. © 2023, EDRA S.p.A. All rights reserved
Pleistocene magnetochronology of early hominin sites at Ceprano and Fontana Ranuccio, Italy
Paleomagnetic analyses were conducted on two cores drilled at Ceprano in central Italy where an incomplete hominin cranium was discovered in 1994, as well as on two additional cores from the nearby site of Fontana Ranuccio that yielded hominin remains associated with an Acheulean industry. No evidence for the 0.78 Ma Brunhes–Matuyama boundary was found at Ceprano down to 45 m below the level that yielded the hominin cranium. The Ceprano lithostratigraphy and the paleomagnetic age constraints are broadly consistent with the stratigraphy of the Liri lacustrine sequence of the Latina Valley, constrained by published K–Ar ages between ~ 0.6 and ~ 0.35 Ma, and according to an age model with magnetic susceptibility supported by pollen facies data, suggest that the level that yielded the hominin cranium has an age of ~ 0.45 (+ 0.05, − 0.10) Ma. Evidence for the Brunhes–Matuyama boundary was found at Fontana Ranuccio about 40 m below the hominin level, consistent with a K–Ar age of ~ 0.46 Ma reported for this level. Hence the Ceprano and Fontana Ranuccio hominin occurrences may be of very similar mid-Brunhes age
Pleistocene magnetochronology of early hominin sites at Ceprano and Fontana Ranuccio, Italy
Paleomagnetic analyses were conducted on two cores drilled at Ceprano in central Italy where an incomplete hominin cranium was discovered in 1994, as well as on two additional cores from the nearby site of Fontana Ranuccio that yielded hominin remains associated with an Acheulean industry. No evidence for the 0.78 Ma Brunhes–Matuyama boundary was found at Ceprano down to 45 m below the level that yielded the hominin cranium. The Ceprano lithostratigraphy and the paleomagnetic age constraints are broadly consistent with the stratigraphy of the Liri lacustrine sequence of the Latina Valley, constrained by published K–Ar ages between ~ 0.6 and ~ 0.35 Ma, and according to an age model with magnetic susceptibility supported by pollen facies data, suggest that the level that yielded the hominin cranium has an age of ~ 0.45 (+ 0.05, − 0.10) Ma. Evidence for the Brunhes–Matuyama boundary was found at Fontana Ranuccio about 40 m below the hominin level, consistent with a K–Ar age of ~ 0.46 Ma reported for this level. Hence the Ceprano and Fontana Ranuccio hominin occurrences may be of very similar mid-Brunhes age
Father–child bonding and mental health in gay fathers using cross-border surrogacy during the COVID-19 pandemic
- …