3,370 research outputs found
Constraining decaying dark energy density models with the CMB temperature-redshift relation
We discuss the thermodynamic and dynamical properties of a variable dark
energy model with density scaling as , z being the
redshift. These models lead to the creation/disruption of matter and radiation,
which affect the cosmic evolution of both matter and radiation components in
the Universe. In particular, we have studied the temperature-redshift relation
of radiation, which has been constrained using a recent collection of cosmic
microwave background (CMB) temperature measurements up to . We find
that, within the uncertainties, the model is indistinguishable from a
cosmological constant which does not exchange any particles with other
components. Future observations, in particular measurements of CMB temperature
at large redshift, will allow to give firmer bounds on the effective equation
of state parameter for such types of dark energy models.Comment: 9 pages, 1 figure, to appear in the Proceedings of the 3rd
Italian-Pakistani Workshop on Relativistic Astrophysics, Lecce 20-22 June
2011, published in Journal of Physics: Conference Series (JPCS
High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide
The economic value of a climate service for water irrigation. A case study for Castiglione District, Emilia-Romagna, Italy
The use of climate services to support decision makers in incorporating climate change adaptation in their
practices is well established and widely recognized. Their role is particularly relevant in a climate sensitive sector
like agriculture where they can provide evidence for the adoption of transformative solutions from seasonal to
multi-decadal time scales. Adaptation solutions are often expensive and irreversible in the short/medium run.
Accordingly, end users should have a reliable reference to make decisions. Here, we propose and apply a
methodology, co-developed with service developers and a representative potential user, to assess the value of the
IRRICLIME climate service, whose information is used to support decisions on climate smart irrigation investment
by water planners in a sub-irrigation district in Italy. We quantify the value of the information provided by
the climate service, that we consider the intrinsic value of the service, or the value of adaptation. We demonstrate
that under three different climate change scenarios, the maximum potential value of IRRICLIME could range
between 2,985 âŹ/ha and 7,480 âŹ/ha
Pediatric patients tolerance: a comparative study about using of Er:YAG laser and self-adhesive flowable composite for treatment of primary decayed teeth
Aim. To verify the tolerance of children aged between 3 and 8 years, having class I caries and treated with Er:YAG laser in association with a new self-adhesive flowable resin in comparison with a highspeed diamond bur and a conventional flowable resin treatment.
Methods. A group of 80 healthy children (43 males and 37 females) ranging in age from 3 to 8 years, who had been diagnosed with at least one active occlusal non-cavitated superficial carious lesions in first or second deciduous molars, were selected for the present study. They were divided in 4 groups: group A: Class I occlusal cavities prepared using an Er: YAG laser and a self-adhesive flowable resin; Group B: Class I occlusal cavities prepared using an Er: YAG laser and a conventional flowable resin; Group C: Class I occlusal cavities prepared using a high-speed diamond bur and a self-adhesive flowable resin; Group D: Class I occlusal cavities prepared using a high-speed diamond bur and a conventional flowable resin. Before and after the treatments the patient tolerance was tested with the modified Wong-Baker pain level scale.
Results. In the first group, the tolerance rate was 95% with 0 score (no hurt) for 19 patients; in Group D, the tolerance rate was 75%. Just one child of group D experienced hurting worst because of non cooperative patient.
Conclusion. From these results it emerged that, although the limits of the study, Er:Yag laser in association with self-adhering composite, is very effective in pediatric dentistry and is a good treatment option especially for non cooperative patients
Cross-cultural adaptation, reliability and validity of the Italian version of the craniofacial pain and disability inventory in patients with chronic temporomandibular joint disorders
BACKGROUND: To develop an Italian version of the Craniofacial Pain Disability Inventory (CFPDI-I) and investigate its psychometric abilities in patients with temporomandibular disorders (TMD). METHODS: The CFPDI was translated following international standards. The psychometric analyses included reliability by internal consistency (Cronbach's alpha) and test/retest stability (intraclass correlation coefficient, ICC); construct validity was investigated by matching (a priori hypotheses) the CFPDI-I with the Italian Neck Disability Index (NDI-I), a pain intensity numerical rating scale (NRS), the Italian Pain Catastrophising Scale (PCS-I), the Italian Tampa Scale of Kinesiophobia (TSK-I), and the Italian Migraine Disability Assessment Score Questionnaire (MIDAS) (Pearson's correlation). Alpha was set at 0.05. RESULTS: Two hundred and twelve patients with chronic TMD completed the tool. The questionnaire was internally consistent (\u3b1 =\u20090.95) and its stability was good (ICCs\u2009=\u20090.91). As hypothesised, validity figures showed CFPDI-I strongly correlated with the NDI-I (r =\u20090.66, p <\u20090.05) and moderately correlated with the NRS (r =\u20090.48, p <\u20090.05), PCS (r =\u20090.37, p <\u20090.05), TSKI (r =\u20090.35, p <\u20090.05) and MIDAS (r =\u20090.47, p <\u20090.05). Similar estimates were shown by CFPDI-I subscales. CONCLUSIONS: The cross-culturally adapted version of the Craniofacial Pain and Disability Inventory (CFPDI-I) showed satisfactory psychometric properties that replicate those of the original version and, therefore, can be implemented in the clinical assessment of Italian people affected by TMD
Chiral dynamics of p-wave in K^- p and coupled states
We perform an evaluation of the p-wave amplitudes of meson-baryon scattering
in the strangeness S=-1 sector starting from the lowest order chiral
Lagrangians and introducing explicitly the Sigma^* field with couplings to the
meson-baryon states obtained using SU(6) symmetry. The N/D method of
unitarization is used, equivalent, in practice, to the use of the
Bethe-Salpeter equation with a cut-off. The procedure leaves no freedom for the
p-waves once the s-waves are fixed and thus one obtains genuine predictions for
the p-wave scattering amplitudes, which are in good agreement with experimental
results for differential cross sections, as well as for the width and partial
decay widths of the Sigma^*(1385).Comment: LaTeX, 18 pages, 6 figure
Diffuse-interface model for rapid phase transformations in nonequilibrium systems
A thermodynamic approach to rapid phase transformations within a diffuse
interface in a binary system is developed. Assuming an extended set of
independent thermodynamic variables formed by the union of the classic set of
slow variables and the space of fast variables, we introduce finiteness of the
heat and solute diffusive propagation at the finite speed of the interface
advancing. To describe the transformation within the diffuse interface, we use
the phase-field model which allows us to follow the steep but smooth change of
phases within the width of diffuse interface. The governing equations of the
phase-field model are derived for the hyperbolic model, model with memory, and
for a model of nonlinear evolution of transformation within the
diffuse-interface. The consistency of the model is proved by the condition of
positive entropy production and by the outcomes of the fluctuation-dissipation
theorem. A comparison with the existing sharp-interface and diffuse-interface
versions of the model is given.Comment: 15 pages, regular article submitted to Physical Review
Spin-Momentum Correlations in Quasi-Elastic Electron Scattering from Deuterium
We report on a measurement of spin-momentum correlations in quasi-elastic
scattering of longitudinally polarized electrons with an energy of 720 MeV from
vector-polarized deuterium. The spin correlation parameter was
measured for the reaction for missing
momenta up to 350 MeV/ at a four-momentum transfer squared of 0.21
(GeV/c). The data give detailed information about the spin structure of the
deuteron, and are in good agreement with the predictions of microscopic
calculations based on realistic nucleon-nucleon potentials and including
various spin-dependent reaction mechanism effects. The experiment demonstrates
in a most direct manner the effects of the D-state in the deuteron ground-state
wave function and shows the importance of isobar configurations for this
reaction.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Lett. for publicatio
Electron-deuteron scattering in a current-conserving description of relativistic bound states: formalism and impulse approximation calculations
The electromagnetic interactions of a relativistic two-body bound state are
formulated in three dimensions using an equal-time (ET) formalism. This
involves a systematic reduction of four-dimensional dynamics to a
three-dimensional form by integrating out the time components of relative
momenta. A conserved electromagnetic current is developed for the ET formalism.
It is shown that consistent truncations of the electromagnetic current and the
interaction kernel may be made, order-by-order in the coupling constants,
such that appropriate Ward-Takahashi identities are satisfied. A meson-exchange
model of the interaction is used to calculate deuteron vertex functions.
Calculations of electromagnetic form factors for elastic scattering of
electrons by deuterium are performed using an impulse-approximation current.
Negative-energy components of the deuteron's vertex function and retardation
effects in the meson-exchange interaction are found to have only minor effects
on the deuteron form factors.Comment: 42 pages, RevTe
Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium
We report on a first measurement of tensor analyzing powers in quasi-elastic
electron-deuteron scattering at an average three-momentum transfer of 1.7
fm. Data sensitive to the spin-dependent nucleon density in the deuteron
were obtained for missing momenta up to 150 MeV/ with a tensor polarized
H target internal to an electron storage ring. The data are well described
by a calculation that includes the effects of final-state interaction,
meson-exchange and isobar currents, and leading-order relativistic
contributions.Comment: 4 pages, 3 figure
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