4,778 research outputs found
Water Scarcity and Virtual Water Trade in the Mediterranean
Virtual water trade refers to the implicit content of water in the production of goods and services. When trade is undertaken, there is an implicit exchange of water. Furthermore, when water gets scarce, water intensive goods become more expensive to produce and the economy compensates through higher water imports.This paper is about applying the concept of virtual water to the problem of future water scarcity in the Mediterranean area, also induced by the climate change. The aim is assessing to what extent water trade is a viable adaptation option to the problem of water scarcity. To this end, a computable general equilibrium model is extended with satellite data on sectoral water consumption, and used to assess future scenarios of water availability.It is found that virtual trade may curb the negative effect of water scarcity, yet the consequences in terms of income and welfare remain quite significant, especially for some regions.Computable General Equilibrium Models, Water, Virtual Water, Water Scarcity, Climate Change
Increasing the lensing figure of merit through higher order convergence moments
The unprecedented quality, the increased data set, and the wide area of ongoing and near future weak lensing surveys allows one to move beyond the standard two points statistics, thus making it worthwhile to investigate higher order probes. As an interesting step toward this direction, we explore the use of higher order moments (HOM) of the convergence field as a way to increase the lensing figure of merit (FoM). To this end, we rely on simulated convergence to first show that HOM can be measured and calibrated so that it is indeed possible to predict them for a given cosmological model provided suitable nuisance parameters are introduced and then marginalized over. We then forecast the accuracy on cosmological parameters from the use of HOM alone and in combination with standard shear power spectra tomography. It turns out that HOM allow one to break some common degeneracies, thus significantly boosting the overall FoM. We also qualitatively discuss possible systematics and how they can be dealt with
A Riemann-Hilbert formulation for the finite temperature Hubbard model
Inspired by recent results in the context of AdS/CFT integrability, we
reconsider the Thermodynamic Bethe Ansatz equations describing the 1D fermionic
Hubbard model at finite temperature. We prove that the infinite set of TBA
equations are equivalent to a simple nonlinear Riemann-Hilbert problem for a
finite number of unknown functions. The latter can be transformed into a set of
three coupled nonlinear integral equations defined over a finite support, which
can be easily solved numerically. We discuss the emergence of an exact Bethe
Ansatz and the link between the TBA approach and the results by J\"uttner,
Kl\"umper and Suzuki based on the Quantum Transfer Matrix method. We also
comment on the analytic continuation mechanism leading to excited states and on
the mirror equations describing the finite-size Hubbard model with twisted
boundary conditions.Comment: 43 pages, 13 figures. v2: References added, typos corrected, minor
changes to the text. v3: JHEP published version; typos corrected, references
added and text improved in Section
Minkowski Functionals of Convergence Maps and the Lensing Figure of Merit
Minkowski functionals (MFs) quantify the topological properties of a given
field probing its departure from Gaussianity. We investigate their use on
lensing convergence maps in order to see whether they can provide further
insights on the underlying cosmology with respect to the standard second-order
statistics, i.e., cosmic shear tomography. To this end, we first present a
method to match theoretical predictions with measured MFs taking care of the
shape noise, imperfections in the map reconstruction, and inaccurate
description of the nonlinearities in the matter power spectrum and bispectrum.
We validate this method against simulated maps reconstructed from shear fields
generated by the MICE simulation. We then perform a Fisher matrix analysis to
forecast the accuracy on cosmological parameters from a joint MFs and shear
tomography analysis. It turns out that MFs are indeed helpful to break the
-- degeneracy thus generating a sort of chain
reaction leading to an overall increase of the Figure of Merit.Comment: 16 pages, 5 figures. Matches published version in PR
Comparing disease control policies for interacting wild populations
We consider interacting population systems of predator-prey type, presenting
four models of control strategies for epidemics among the prey. In particular
to contain the transmissible disease, safety niches are considered, assuming
they lessen the disease spread, but do not protect prey from predators. This
represents a novelty with respect to standard ecosystems where the refuge
prevents predators' attacks. The niche is assumed either to protect the healthy
individuals, or to hinder the infected ones to get in contact with the
susceptibles, or finally to reduce altogether contacts that might lead to new
cases of the infection. In addition a standard culling procedure is also
analysed. The effectiveness of the different strategies are compared. Probably
the environments providing a place where disease carriers cannot come in
contact with the healthy individuals, or where their contact rates are lowered,
seem to preferable for disease containment
Climate Change, Tourism and Water Resources in the Mediterranean: A General Equilibrium Analysis
ESO VLT Optical Spectroscopy of BL Lac Objects IV. New spectra and properties of the full sample
We present the last chapter of a spectroscopy program aimed at deriving the
redshift or a lower limit to the redshift of BL Lac objects using medium
resolution spectroscopy. Here we report new spectra for 33 BL Lac object
candidates obtained in 2008-2009 confirming the BL Lac nature of 25 sources and
for 5 objects we obtained new redshifts. These new observations are combined
with our previous data in order to construct a homogeneous sample of \sim 70 BL
Lacs with high quality spectroscopy. All these spectra can be accessed at the
website http://www.oapd.inaf.it/zbllac/. The average spectrum, beaming
properties of the full sample, discussion on intervening systems and future
perspectives are addressed.Comment: 25 pages, 13 Figures. Accepted for publication in the Astronomical
Journa
Ruptured middle cerebral artery aneurysms. retrospective study and multivariate analysis of 105 patients treated by surgical clipping
Objective of the study: We analyze in this study only patients with surgically treated ruptured aneurysms in order to identify statistical significance of each predictive factor in terms of outcome of patients with ruptured MCAAs. Materials and methods: In this retrospective study, we analyzed 105 cases of ruptured MCAAs, admitted from January 2001 to December 2015 at Neurosurgical Department of Umberto I University Hospital of Rome, Italy. Predictive factors evaluated are: Patient’s features (age, sex, co-morbidities), aneurysmal location (proximal, bifurcation or distal) and size of aneurysmal dome (small, large or giant); surgical timing (ultra-early, early, delayed), and Intracerebral Hemorrhage (ICH) volume. For each parameter we calculated mean and standard deviation, covariance and relation coefficient (through the linear regression model). Results: The clinical evaluation of patients assessed through the World Federation of Neurological Surgeons (WFSN) grading scale, that is 5 for 37 patients (35.3%), 4 for 28 patients. In 40% of cases the maximum sac diameter was between 7 mm and 12 mm, while in 67% of the cases the aneurysms concerned the bifurcation of the middle cerebral artery. ICH was associated in 57 cases (54.3%). As far as outcome is concerned, at 3 months, 32 patients (30.47%) had a favourable outcome, while 73 (69.52%) patients had not favourable outcome. To one year, 46 patients (43.8%) had favourable outcomes, while 59 patients (56.19%) had not favourable outcome. The mean outcomes as mean mRS are significantly less favourable in patients with ICH. Conclusion: In MCAAs patients, the presence of ICH strongly affects the outcome with a marked increase in mortality and morbidity. Surgical timing significantly influences the outcomes and ultra-early surgery should always be taken into account
Simulating populations of protocells with uneven division
Protocells should be similar to present-day biological cells, but much simpler. They are believed to have played a key role in the origin of life, and they may also be the basis of a new technology with tremendous opportunities. In this work we study the effect of uneven division processes on the synchronization of the duplication rates of protocells’ membrane and internal materials
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