2,216 research outputs found
The effects of Non-Gaussian initial conditions on the structure and substructure of Cold Dark Matter halos
We study the structure and substructure of halos obtained in N-body
simulations for a Lambda Cold Dark Matter (LCDM) cosmology with non-Gaussian
initial conditions (NGICs). The initial statistics are lognormal in the
gravitational potential field with positive (LNp) and negative (LNn) skewness;
the sign of the skewness is conserved by the density field, and the power
spectrum is the same for all the simulations. Our aim is not to test a given
non-Gaussian statistics, but to explore the generic effect of positive- and
negative-skew statistics on halo properties. From our low-resolution
simulations, we find that LNp (LNn) halos are systematically more (less)
concentrated than their Gaussian counterparts. This result is confirmed by our
Milky Way- and cluster-sized halos resimulated with high-resolution. In
addition, they show inner density profiles that depend on the statistics: the
innermost slopes of LNp (LNn) halos are steeper (shallower) than those obtained
from the corresponding Gaussian halos. A subhalo population embedded in LNp
halos is more susceptible to destruction than its counterpart inside Gaussian
halos. On the other hand, subhalos in LNn halos tend to survive longer than
subhalos in Gaussian halos. The spin parameter probability distribution of LNp
(LNn) halos is skewed to smaller (larger) values with respect to the Gaussian
case. Our results show how the statistics of the primordial density field can
influence some halo properties, opening this the possibility to constrain,
although indirectly, the primordial statistics at small scale.Comment: 15 pages, 8 figures. Slight corrections after referee report. To
appear in ApJ, v598, November 20, 200
Lanthanide-Based Complexes Containing a Chiral trans-1,2-Diaminocyclohexane (DACH) Backbone: Spectroscopic Properties and Potential Applications
In this minireview, we give an overview on the use of the chiral molecule trans-1,2-diaminocyclohexane (DACH) in several fields of application. This chiral backbone is present in a variety of metal complexes which are employed in (enantioselective) catalysis, chiral discrimination, molecular recognition and supramolecular chemistry. Metal extraction and biochemical and pharmaceutical applications also use the DACH molecule. This contribution is particularly focused on the interesting chemical-physical properties discussed so far in the literature concerning lanthanide-based complexes containing chiral ligands characterized by the presence of DACH in the structure. In particular, the interconnection between luminescence (total and circularly polarized), structure and thermodynamics of Eu(III), Tb(III) and Sm(III) complexes will be discussed also in light of their use as optical or chiroptical probes for the sensing of important analytes dissolved in aprotic and protic polar solvents. Several complexes show potential interest in the solid state as phosphors for light emitting devices or for the detection of volatile organic compounds
Could Dietary Goals and Climate Change Mitigation Be Achieved Through Optimized Diet? The Experience of Modeling the National Food Consumption Data in Italy
Objective: The aim of this study is to define a healthy and sustainable diet model with low GHGE, fulfilling dietary requirements, and considering current Italian food consumption patterns. Design: A duly designed database was developed, linking food nutritional composition and GHGE based on 921 food items consumed in Italy according to the last national food consumption survey (INRAN-SCAI 2005–2006). Linear programming was used to develop new diet plans separately for males and females, aged 18–60 years (n = 2,098 subjects), in order to minimize GHGE. The program is based on dietary goals and acceptability constraints as well as on 13 nutrient requirement constraints aiming to reach a healthy and acceptable diet for the Italian population. Results: Diet optimization resulted in a nutritionally adequate pattern minimizing GHGE values (4.0 vs. 1.9 kg CO2e/day for males and 3.2 vs. 1.6 kg CO2e/day for females). In both sexes, the nutrient intake of the optimized diet was at the established lower bound for cholesterol and calcium and at the established upper bound for free sugar and fiber. In males, intake of zinc was at the established lower bound whereas iron was at the established upper bound. Consumption of red meat and fruit and vegetables was at the established lower and upper bound, respectively, in both males and females. Despite the decrease in meat consumption, especially red meat, in the optimized diet with respect to the observed diet, levels of iron intake in females increased by 10% (10.3 vs. 11.3 mg/day) but remained below the adequate intake established in Italian national DRIs. Conclusions: An attainable healthy dietary pattern was developed that would lead to the reduction of GHGE by 48% for males and by 50% for females with respect to current food consumption in the Italian adult population. Health-promoting dietary patterns can substantially contribute to achieve related Sustainable Development Goals
Baryogenesis and CP-Violating Domain Walls in the Background of a Magnetic Field
Within the domain wall-mediated electroweak baryogenesis, we study fermion
scattering off a CP-violating wall in the background of an uniform magnetic
field. In particular, we calculate the asymmetry between the reflection
coefficients for right-handed and left-handed chiral fermions, \Delta R = R_{R
\to L} - R_{L \to R}, which is of relevance to non local baryogenesis
mechanisms.Comment: replaced with revised conclusion version, to be published in JCA
Faraday rotation, stochastic magnetic fields and CMB maps
The high- and low-frequency descriptions of the pre-decoupling plasma are
deduced from the Vlasov-Landau treatment generalized to curved space-times and
in the presence of the relativistic fluctuations of the geometry. It is
demonstrated that the interplay between one-fluid and two-fluid treatments is
mandatory for a complete and reliable calculation of the polarization
observables. The Einstein-Boltzmann hierarchy is generalized to handle the
dispersive propagation of the electromagnetic disturbances in the
pre-decoupling plasma. Given the improved physical and numerical framework, the
polarization observables are computed within the magnetized CDM
paradigm (mCDM). In particular, the Faraday-induced B-mode is
consistently estimated by taking into account the effects of the magnetic
fields on the initial conditions of the Boltzmann hierarchy, on the dynamical
equations and on the dispersion relations. The complete calculations of the
angular power spectra constitutes the first step for the derivation of
magnetized maps of the CMB temperature and polarization which are here obtained
for the first time and within the minimal mCDM model. The obtained
results set the ground for direct experimental scrutiny of large-scale
magnetism via the low and high frequency instruments of the Planck explorer
satellite.Comment: 53 pages, 15 included figure
Fermion scattering off electroweak phase transition kink walls with hypermagnetic fields
We study the scattering of fermions off a finite width kink wall during the
electroweak phase transition in the presence of a background hypermagnetic
field. We derive and solve the Dirac equation for such fermions and compute the
reflection and transmission coefficients for the case when the fermions move
from the symmetric to the broken symmetry phase. We show that the chiral nature
of the fermion coupling with the background field in the symmetric phase
generates an axial asymmetry in the scattering processes. We discuss possible
implications of such axial charge segregation for baryon number generation.Comment: 9 pages, 3 Postscript figures, uses RevTeX4. Expanded discussion,
published versio
Cold Formalin Fixation Guarantees DNA Integrity in Formalin Fixed Paraffin Embedded Tissues: Premises for a Better Quality of Diagnostic and Experimental Pathology With a Specific Impact on Breast Cancer
Nutritional characterization of Cicer arietinum L. cultivars with respect to morphological and agronomic parameters
Chickpea (Cicer arietinum L.) is one of the grain legumes more interesting for its nutritional value and genetic improvement in order to resistance to Aschochyta rabiei, seeds weight and adaptation to mechanical harvesting. The aim of this research was the agronomic and qualitative characterization of 15 cultivars of chickpea. During the cultural cycle resistance and sensitiveness to Aschochyta rabiei were analyzed. At harvesting, grain yield and yields components were registered. Moreover, proximate composition, fatty acids content and saturated/unsaturated ratio of grain samples were determined. Cultivars with high 1000 seeds weight showed a more favourable oleic acid content and unsaturated/saturated ratio but those with smooth seeds had a higher content in linolenic acid. All cultivars showed high values of polyunsaturated fatty acids (42.9-56.2%), inferior of monounsaturated (29.5-36.1%) and low of saturated (10.0-22.9%). Black chickpea (2.9) had the lowest unsaturated/saturated ratio, while the highest was noticed for cv. Visir (7.46). Cultivars with small and smooth seeds showed a better proteins content. These results showed availability of seeds with favourable characteristics useful for different utilization. In particular, the cultivars with small and smooth seeds, usually not preferred by consumers, seem to be interesting for processing in nutritional foods and dietetics
High BRAF variant allele frequencies are associated with distinct pathological features and responsiveness to target therapy in melanoma patients
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