1,309 research outputs found
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Emergence of Venice during the Pleistocene
The Pleistocene history of sea-level change for the Venice region was reconstructed using an integrated magneto-bio-cyclo-stratigraphy of lithofacies and a published palynofloral analysis of continuously cored sediments in a 950-meter-deep drill core. The basin in which the Venice region is located collapsed at ∼1.8 Ma with slow sediment accumulation in the deeper-water starved basin during most of the Matuyama polarity chron but shoaled rapidly in the early and middle Brunhes in response to a major phase of deltaic progradation. The initial transition to continental sediments occurred during a prominent glacioeustatic low-stand that is likely to be MIS 12 (∼0.43 Ma) but could be as young as MIS 8 (∼0.25 Ma). The Venice area oscillated from below sea level during subsequent major glacioeustatic high-stands to becoming increasingly emergent during major low-stands as the basin continued to fill with marine and continental sediments. Some parts of the Venice area are now emergent for the first time during a glacioeustatic high-stand (i.e., MIS 1 or the Holocene). The total long-term subsidence rate estimated from the VENICE-1 record is less than 0.5 mm/yr, considerably slower than estimates for the Holocene and especially the modern anthropogenic period
Recommended from our members
Emergence of Venice during the Pleistocene
The Pleistocene history of sea-level change for the Venice region was reconstructed using an integrated magneto-bio-cyclo-stratigraphy of lithofacies and a published palynofloral analysis of continuously cored sediments in a 950-meter-deep drill core. The basin in which the Venice region is located collapsed at ∼1.8 Ma with slow sediment accumulation in the deeper-water starved basin during most of the Matuyama polarity chron but shoaled rapidly in the early and middle Brunhes in response to a major phase of deltaic progradation. The initial transition to continental sediments occurred during a prominent glacioeustatic low-stand that is likely to be MIS 12 (∼0.43 Ma) but could be as young as MIS 8 (∼0.25 Ma). The Venice area oscillated from below sea level during subsequent major glacioeustatic high-stands to becoming increasingly emergent during major low-stands as the basin continued to fill with marine and continental sediments. Some parts of the Venice area are now emergent for the first time during a glacioeustatic high-stand (i.e., MIS 1 or the Holocene). The total long-term subsidence rate estimated from the VENICE-1 record is less than 0.5 mm/yr, considerably slower than estimates for the Holocene and especially the modern anthropogenic period
Recommended from our members
Emergence of Venice during the Pleistocene
The Pleistocene history of sea-level change for the Venice region was reconstructed using an integrated magneto-bio-cyclo-stratigraphy of lithofacies and a published palynofloral analysis of continuously cored sediments in a 950-meter-deep drill core. The basin in which the Venice region is located collapsed at ∼1.8 Ma with slow sediment accumulation in the deeper-water starved basin during most of the Matuyama polarity chron but shoaled rapidly in the early and middle Brunhes in response to a major phase of deltaic progradation. The initial transition to continental sediments occurred during a prominent glacioeustatic low-stand that is likely to be MIS 12 (∼0.43 Ma) but could be as young as MIS 8 (∼0.25 Ma). The Venice area oscillated from below sea level during subsequent major glacioeustatic high-stands to becoming increasingly emergent during major low-stands as the basin continued to fill with marine and continental sediments. Some parts of the Venice area are now emergent for the first time during a glacioeustatic high-stand (i.e., MIS 1 or the Holocene). The total long-term subsidence rate estimated from the VENICE-1 record is less than 0.5 mm/yr, considerably slower than estimates for the Holocene and especially the modern anthropogenic period
p-species integrable reaction-diffusion processes
We consider a process in which there are p-species of particles, i.e.
A_1,A_2,...,A_p, on an infinite one-dimensional lattice. Each particle
can diffuse to its right neighboring site with rate , if this site is not
already occupied. Also they have the exchange interaction A_j+A_i --> A_i+A_j
with rate We study the range of parameters (interactions) for which
the model is integrable. The wavefunctions of this multi--parameter family of
integrable models are found. We also extend the 2--species model to the case in
which the particles are able to diffuse to their right or left neighboring
sites.Comment: 16 pages, LaTe
Association between Stress Urinary Incontinence and Depressive Symptoms after Birth: the Czech ELSPAC Study
The study objectives were to (1) identify risk factors related to stress urinary incontinence (SUI) and
postnatal depression (PD) after birth, and (2) investigate both possible directions of association
between SUI and PD in population-based sample of Czech mothers. 3,701 nulliparous and multiparous
women completed the self-reported questionnaires at 6 weeks and 6 months after birth and were
included into the analyses of this prospective cohort study. Unadjusted and adjusted logistic regressions
examined relationship between SUI a PD accounting for range of other risk factors. During the frst 6
months after birth, 650 mothers (17.6%) developed SUI and 641 (17.3%) displayed signs of PD. The
mode of delivery, parity and higher BMI were associated with SUI. The rate of PD symptoms was higher
in mothers with positive history of prenatal depression, and in divorced or widowed mothers. Both
conditions were associated with worse self-reported health, back pain and stop-smoker status. Initially,
SUI at 6 weeks was slightly, but signifcantly associated with onset of PD at 6 months (OR 1.51, 95%
CI 1.02–2.23) while PD at 6 weeks was not signifcantly related to new cases of SUI at 6 months (OR
1.48, 95% CI 0.91–2.39). After full adjustment these OR reduced to 1.41 and 1.38 (both non-signifcant),
respectively. SUI and PD are common conditions in women postpartum that share some risk factors.
Our study suggests that both directions of their relationship are possible although a larger study is
needed to confrm our fndings
An interacting spin flip model for one-dimensional proton conduction
A discrete asymmetric exclusion process (ASEP) is developed to model proton
conduction along one-dimensional water wires. Each lattice site represents a
water molecule that can be in only one of three states; protonated,
left-pointing, and right-pointing. Only a right(left)-pointing water can accept
a proton from its left(right). Results of asymptotic mean field analysis and
Monte-Carlo simulations for the three-species, open boundary exclusion model
are presented and compared. The mean field results for the steady-state proton
current suggest a number of regimes analogous to the low and maximal current
phases found in the single species ASEP [B. Derrida, Physics Reports, {\bf
301}, 65-83, (1998)]. We find that the mean field results are accurate
(compared with lattice Monte-Carlo simulations) only in the certain regimes.
Refinements and extensions including more elaborate forces and pore defects are
also discussed.Comment: 13pp, 6 fig
Two interacting diffusing particles on low-dimensional discrete structures
In this paper we study the motion of two particles diffusing on
low-dimensional discrete structures in presence of a hard-core repulsive
interaction. We show that the problem can be mapped in two decoupled problems
of single particles diffusing on different graphs by a transformation we call
'diffusion graph transform'. This technique is applied to study two specific
cases: the narrow comb and the ladder lattice. We focus on the determination of
the long time probabilities for the contact between particles and their
reciprocal crossing. We also obtain the mean square dispersion of the particles
in the case of the narrow comb lattice. The case of a sticking potential and of
'vicious' particles are discussed.Comment: 9 pages, 6 postscript figures, to appear in 'Journal of Physics
A',-January 200
Cohort Profile: The European Longitudinal Study of Pregnancy and Childhood (ELSPAC) in the Czech Republic
Group report: What are the observed and anticipated meteorological and climatic responses to aerosol forcing?
Exact time-dependent correlation functions for the symmetric exclusion process with open boundary
As a simple model for single-file diffusion of hard core particles we
investigate the one-dimensional symmetric exclusion process. We consider an
open semi-infinite system where one end is coupled to an external reservoir of
constant density and which initially is in an non-equilibrium state
with bulk density . We calculate the exact time-dependent two-point
density correlation function and the mean and variance of the integrated average net flux
of particles that have entered (or left) the system up to time .
We find that the boundary region of the semi-infinite relaxing system is in a
state similar to the bulk state of a finite stationary system driven by a
boundary gradient. The symmetric exclusion model provides a rare example where
such behavior can be proved rigorously on the level of equal-time two-point
correlation functions. Some implications for the relaxational dynamics of
entangled polymers and for single-file diffusion in colloidal systems are
discussed.Comment: 11 pages, uses REVTEX, 2 figures. Minor typos corrected and reference
17 adde
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