6,309 research outputs found
Lepton Mixing from Delta (3 n^2) and Delta (6 n^2) and CP
We perform a detailed study of lepton mixing patterns arising from a scenario
with three Majorana neutrinos in which a discrete flavor group Gf=Delta (3 n^2)
or Gf=Delta(6 n^2) and a CP symmetry are broken to residual symmetries Ge=Z3
and Gnu=Z2 x CP in the charged lepton and neutrino sectors, respectively. While
we consider all possible Z3 and Z2 generating elements, we focus on a certain
set of CP transformations. The resulting lepton mixing depends on group
theoretical indices and one continuous parameter. In order to study the mixing
patterns comprehensively for all admitted Ge and Gnu, it is sufficient to
discuss only three types of combinations. One of them requires as flavor group
Delta (6 n^2). Two types of combinations lead to mixing patterns with a
trimaximal column, while the third one allows for a much richer structure. For
the first type of combinations the Dirac as well as one Majorana phase are
trivial, whereas the other two ones predict in general all CP phases to be
non-trivial and also non-maximal. Already for small values of the index n of
the group, n <= 11, experimental data on lepton mixing can be accommodated well
for particular choices of the parameters of the theory. We also comment on the
relation of the used CP transformations to the automorphisms of Delta (3 n^2)
and Delta (6 n^2).Comment: 60 pages, 12 tables and 10 figures. v2: typos corrected, references
updated, some minor improvement of the text, matches version accepted for
publication in Nuclear Physics
Two-zero Majorana textures in the light of the Planck results
The recent results of the Planck experiment put a stringent constraint on the
sum of the light neutrino masses, m1+m2+m3 < 0.23 eV (95 % CL). On the other
hand, two-zero Majorana mass matrix textures predict strong correlations among
the atmospheric angle and the sum of the masses. We use the Planck result to
show that, for the normal hierarchy case, the texture with vanishing (2,2) and
(3,3) elements is ruled out at a high confidence level; in addition, we
emphasize that a future measurement of the octant of the atmospheric mixing
angle (or the one sigma determination of it based on recent fit to neutrino
data) will put severe constraint on the possible structure of the Majorana mass
matrix. The implication of the above mentioned correlations for neutrinoless
double beta-decay are also discussed, for both normal and inverted orderings.Comment: 9 pages, 8 figure
Design for services and place development
Services are a constituent element of urban planning.
Nevertheless, a new perspective arises when considering
regional contexts, and when considering services
as an approach to design and subject matter for design.
The essay presents reflections raised by a group of
projects in various parts of the world, conducted by local
research partners within the international DESIS
Network (Design for Social Innovation and Sustainability)
and dealing with agricultural periurban territories.
These projects are methodologically related to one currently
in progress in Milan conducted by the Politecnico
di Milano, Slow Food and UniversitĂ Scienze Gastronomiche,
which is expected to generate a scenario of
sustainable local food production and consumption for
the region
Infinite compressibility states in the Hierarchical Reference Theory of fluids. II. Numerical evidence
Continuing our investigation into the Hierarchical Reference Theory of fluids
for thermodynamic states of infinite isothermal compressibility kappa[T] we now
turn to the available numerical evidence to elucidate the character of the
partial differential equation: Of the three scenarios identified previously,
only the assumption of the equations turning stiff when building up the
divergence of kappa[T] allows for a satisfactory interpretation of the data. In
addition to the asymptotic regime where the arguments of part I
(cond-mat/0308467) directly apply, a similar mechanism is identified that gives
rise to transient stiffness at intermediate cutoff for low enough temperature.
Heuristic arguments point to a connection between the form of the Fourier
transform of the perturbational part of the interaction potential and the
cutoff where finite difference approximations of the differential equation
cease to be applicable, and they highlight the rather special standing of the
hard-core Yukawa potential as regards the severity of the computational
difficulties.Comment: J. Stat. Phys., in press. Minor changes to match published versio
Integrated Analysis and Tools for Land Subsidence Surveying and Monitoring: a Semi-Quantitative Approach
This paper presents an integrated approach for land subsidence monitoring using measures coming from different sensors. Eni S.p.A., the main Italian oil and gas company, constantly surveys the land with all the state of the art and innovative techniques, and a method able to integrate the results is an important and actual topic. Nowadays the world is a multi-sensor platform, and measure integration is strictly necessary. Combining the different data sources should be done in a clever way, taking advantages from the best performances of each technique. An integrated analysis allows the interpretation of simultaneous temporal series of data, coming from different sources, and try to separate subsidence contributions. With this purpose Exelis VIS in collaboration with Eni S.p.A. customize PISAV (Permanent Interferometric Scatterometer Analysis and Visualization), an ENVI extension able to capitalize on and combine all the different data collected in the surveys. In this article are presented some significant examples to show the potential of this tool in oil and gas activity: a hydrocarbon storage field where the comparison between SAR and production volumes emphasise a correlation between the two measures in few steps; and a hydrocarbon production field with the Satellite Survey Unit (S.S.U.), where SAR, CGPS, piezometers and assestimeters measure in the same area at the same time, giving the opportunity to analyse data contextually. In the integrated analysis performed with PISAV not always a mathematical rigorous study is possible, and a semi-quantitative approach is the only method for results interpretation. As a result, in the first test case strong correlation between injected hydrocarbon volume and vertical displacement were highlighted; in the second one the integrated analysis has different advantages in monitoring the land subsidence: permits a first qualitative "differentiation" of the natural and anthropic component of subsidence, and also gives more reliability and coverage to each measurement, taking advantages from the strong points of each technique
Implementation of the Hierarchical Reference Theory for simple one-component fluids
Combining renormalization group theoretical ideas with the integral equation
approach to fluid structure and thermodynamics, the Hierarchical Reference
Theory is known to be successful even in the vicinity of the critical point and
for sub-critical temperatures. We here present a software package independent
of earlier programs for the application of this theory to simple fluids
composed of particles interacting via spherically symmetrical pair potentials,
restricting ourselves to hard sphere reference systems. Using the hard-core
Yukawa potential with z=1.8/sigma for illustration, we discuss our
implementation and the results it yields, paying special attention to the core
condition and emphasizing the decoupling assumption's role.Comment: RevTeX, 16 pages, 2 figures. Minor changes, published versio
Nutrition and genetics in NAFLD : The perfect binomium
Nonalcoholic fatty liver disease (NAFLD) represents a global healthcare burden since it is epidemiologically related to obesity, type 2 diabetes (T2D) and Metabolic Syndrome (MetS). It embraces a wide spectrum of hepatic injuries, which include simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The susceptibility to develop NAFLD is highly variable and it is influenced by several cues including environmental (i.e., dietary habits and physical activity) and inherited (i.e., genetic/epigenetic) risk factors. Nonetheless, even intestinal microbiota and its by-products play a crucial role in NAFLD pathophysiology. The interaction of dietary exposure with the genome is referred to as \u2018nutritional genomics,\u2019 which encompasses both \u2018nutrigenetics\u2019 and \u2018nutriepigenomics.\u2019 It is focused on revealing the biological mechanisms that entail both the acute and persistent genome-nutrient interactions that influence health and it may represent a promising field of study to improve both clinical and health nutrition practices. Thus, the premise of this review is to discuss the relevance of personalized nutritional advices as a novel therapeutic approach in NAFLD tailored management
RNA IN DNA: FROM STRUCTURE TO GENOME INSTABILITY
The presence of RNA in the genome of living cells is one of the emerging topics of the last two decades and has been implicated in many biological processes. I focused my attention on ribonucleotides (rNMPs) embedded into DNA during genome duplication, as a threat to its integrity. In fact, rNMPs have been classified as the most frequent non-canonical nucleotides introduced during genome duplication by DNA polymerases. Such high incorporation frequency has been related to a physiological role in mismatch repair, but it can be easily turned into a source of genomic instability if rNMPs are not removed from DNA. This task is performed by RNase H activities that enable error-free repair of embedded single and multiple ribonucleotides.
I first approached the issue of ribonucleotides incorporation into DNA from a physical point of view. Utilizing Atomic Force Microscopy I studied how ribonucleotides intrusions impact on DNA structure. The results obtained provided new insights on the structural changes imposed by ribonucleotides persistence into DNA. The other part of my Ph.D. project concerned the study of rNMPs incorporation in vivo, using the budding yeast S. cerevisiae as a model organism. The second aim was to unravel the function of the Translesion Synthesis polymerase \u3b7 (Pol \u3b7) when the genome contains residual ribonucleotides and when deoxyribonucleotides (dNTPs) pools are depleted. We found that DNA polymerase \u3b7 is responsible for the cell lethality observed when dNTPs are scarce and RNase H activities are defective. Therefore, I explored and characterized this unexpected toxic activity. We propose a model where Pol \u3b7 supports cell survival in low dNTPs conditions by promoting DNA replication using ribonucleotides. While this activity is normally beneficial to wild type cells, it is highly toxic to cells defective for RNase H activities
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