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Search Results: 1 - 10 of 7117 matches for " Daniela Giardino "
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Axisymmmetric Empty Space: Light Propagation, Orbits and Dark Matter  [PDF]
Sergio Giardino
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.515141
Abstract: This study presents an axisymmetric solution of the Einstein equations for empty space. The geometry is studied by determining its Petrov classification and killing vectors. Light propagation, orbital motion and asymptotic and Newtonian limits are also studied. Additionally, cosmological applications of the geometry are also outlined as an alternative model for the inflationary universe and as a substitute for dark matter and quintessence.
Angular invariant quantum mechanics in arbitrary dimension
Sergio Giardino
Physics , 2012,
Abstract: One dimensional quantum mechanics problems, namely the infinite potential well, the harmonic oscillator, the free particle, the Dirac delta potential, the finite well and the finite barrier are generalized for finite arbitrary dimension in a radially symmetric, or angular invariant, manner. This generalization enables the Schr\"{o}dinger equation solutions to be visualized for Bessel functions and Whittaker functions, and it also enables connections to multi-dimensional physics theories, like string theory.
M?bius transformation for left-derivative quaternion holomorphic functions
Sergio Giardino
Physics , 2015,
Abstract: Holomorphic quaternion functions only admit affine functions; thus, the M\"obius transformation for these functions, which we call quaternionic holomorphic transformation (QHT), only comprises similarity transformations. We determine a general group $\mathsf{X}$ which has the group $\mathsf{G}$ of QHT as a particular case. Furthermore, we observe that the M\"obius group and the Heisenberg group may be obtained by making $\mathsf{X}$ more symmetric. We provide matrix representations for the group $\mathsf{X}$ and for its algebra $\mathfrak{x}$. The Lie algebra is neither simple nor semi-simple, and so it is not classified among the classical Lie algebras. They prove that the group $\mathsf{G}$ comprises $\mathsf{SU}(2,\mathbb{C})$ rotations, dilations and translations. The only fixed point of the QHT is located at infinity, and the QHT does not admit a cross-ratio. Physical applications are addressed at the conclusion.
The role of geoscientists in human progress
Stefania Lucchesi,Marco Giardino
Annals of Geophysics , 2012, DOI: 10.4401/ag-5535
Abstract: Like any science, geology has a key role in the development and progress of human culture and society. In this context, scientists, professionals and practitioners of Earth sciences must inevitably confront themselves with the purposes, methods and results of their studies, concerning relationships between man and his environment, which thus deals with ethical questions. An essential base for any geo-environmental action should be respect for the natural ecosystem. This can be achieved by encouraging an ‘affectionate attitude’ towards Nature or ecology. Some ancient cultures had a great awareness of the close relationships between humankind and the Earth. The recent web-based ‘Museo Torino’ (Turin Museum) multimedia product shows the ‘history of a city’ (Turin, Italy) in a dimension of unity and as a continuum of space–time–life between the history of the Earth and of humans. Geoscientists are not limited to merely having a pragmatic vision of the Earth, but should pursue harmonious collaboration between man and Nature. Within complex Earth systems, scientists and professionals rediscover their geoethical roles by responsibly evaluating and managing georesources, for progress aimed at improving conditions of life and human dignity. Geoscientists can also promote respect for ‘human rights’ through appropriate educational and training actions, for the balanced exploitation of our georesources. An example from Mendoza (Argentina) is presented here, to encourage opportunities for meetings on environmental issues among people of different backgrounds and cultures. Last, but not least, there is the ethical role of geoscientists in ‘the service of the truth’. A misleading view of Earth systems by geoscientists can lead to fatalism or myths that often affect people from the psychological and sociological points of view.
Constraints on the physical properties of the damped Ly-alpha system of Q0000-2619 at z = 3.054
G. Giardino,F. Favata
Physics , 2000,
Abstract: We present the detection of CII and CII* absorption in the z = 3.0543 damped Ly-alpha system toward Q0000-2619. The derived population ratio implies a fine structure excitation temperature between 19.6 and 21.6 K. The upper value sets a strict upper limit on the CMB temperature at this redshift, which is consistent with the predicted value of 11.05 K from standard cosmology. Under the assumptions of an ionization degree ranging from 0 to 10%, a gas kinetic temperature between 100 and 10000 K and a UV field with a Milky Way spectrum, the density of the absorber is constrained to be between 0.7 and 40 cm^-3 and the H-ionizing flux between 1 and 80 times the intensity of the Galactic UV field. If the damped Ly-alpha system is assumed to be homogeneous, the implication is that its size in the direction of the line of sight must be between 1 and 100 pc.
Juxtaposition of heterochromatic and euchromatic regions by chromosomal translocation mediates a heterochromatic long-range position effect associated with a severe neurological phenotype
Palma Finelli, Silvia Sirchia, Maura Masciadri, Milena Crippa, Maria Recalcati, Daniela Rusconi, Daniela Giardino, Laura Monti, Francesca Cogliati, Francesca Faravelli, Federica Natacci, Leonardo Zoccante, Bernardo Bernardina, Silvia Russo, Lidia Larizza
Molecular Cytogenetics , 2012, DOI: 10.1186/1755-8166-5-16
Abstract: FISH mapped the translocation breakpoints (bkps) to 15p11.2 within satellite III and the 16q12.1 euchromatic band within the ITFG1 gene. The expression of the genes located on both sides of the translocation were tested by means of real-time PCR and three, all located on der(16), were found to be variously perturbed: the euchromatic gene NETO2/BTCL2 was silenced, whereas VPS35 and SHCBP1, located within the major heterochromatic block of chromosome 16q11.2, were over-expressed. Pyrosequencing and chromatin immunoprecipitation of NETO2/BTCL2 and VPS35 confirmed the expression findings. Interphase FISH analysis showed that der(16) localised to regions occupied by the beta satellite heterochromatic blocks more frequently than der(15).To the best of our knowledge, this is the first report of a heterochromatic position effect in humans caused by the juxtaposition of euchromatin/heterochromatin as a result of chromosomal rearrangement. The overall results are fully in keeping with the observations in Drosophila and suggest the occurrence of a human heterochromatin position effect associated with the nuclear repositioning of the der(16) and its causative role in the patient's syndromic phenotype.Patients with syndromic clinical phenotypes include an interesting subset of carriers of de novo balanced chromosomal rearrangements with no apparent loss or gain of genetic material. These abnormalities can be explained by the loss of function of a dose-sensitive gene disrupted by one rearrangement breakpoint [1-3]. The breakpoints of the balanced chromosomal rearrangements associated with a clinical phenotype are often molecularly mapped in an attempt to identify the disease-causing genes affected by the abnormality. Although the rearrangements may lead to the direct disruption of one or two genes, this is not always the case. It has also been shown that breakpoints occur outside the genes themselves and affect their regulation by causing a change in their position within the gen
Genetic investigations on 8 patients affected by ring 20 chromosome syndrome
Daniela Giardino, Aglaia Vignoli, Lucia Ballarati, Maria Recalcati, Silvia Russo, Nicole Camporeale, Margherita Marchi, Palma Finelli, Patrizia Accorsi, Lucio Giordano, Francesca La Briola, Valentina Chiesa, Maria Canevini, Lidia Larizza
BMC Medical Genetics , 2010, DOI: 10.1186/1471-2350-11-146
Abstract: We submitted 8 subjects with a previous diagnosis of ring 20 chromosome mosaicism to a clinical re-evaluation, followed by cytogenetic, FISH, array-CGH and molecular analyses. The genetic study was also extended to their available parents.FISH and array-CGH experiments indicate that cryptic deletions on chromosome 20 are not the cause of the r(20) chromosome associated disease. Moreover, no evidence of chromosome 20 uniparental disomy was found. Analysis of FISH signals given by variant in size alphoid tandem repeats probes on the normal chromosome 20 and the r(20) chromosome in the mosaic carriers suggests that the r(20) chromosome is the same chromosome not circularized in the "normal" cell line.Higher percentages of r(20) chromosome cells were observed to be related with precocious age at seizure onset and with resistance to antiepileptic drug treatment. Behavioural problems also seem to be associated with higher percentages of r(20) chromosome cells. Our results suggest that an epigenetic mechanism perturbing the expression of genes close to the telomeric regions, rather than deletion of genes located at the distal 20p and/or 20q regions, may underlie the manifestation of r(20) syndrome.Mosaic Chromosome 20 ring [r(20)] is a chromosomal disorder that has been associated with a rare syndrome characterized by a typical seizure phenotype consisting of complex partial seizures, a particular electroclinical pattern, cognitive impairment, behavioural problems and absence of a consistent pattern of dysmorphology [1-4]. Over 60 cases have been reported up to now, mostly sporadic, with mosaicism for a de novo r(20) chromosome resulting in refractory epilepsy with non convulsive status epilepticus (NCSE) and cognitive problems [5-7]. A reassessment of the published cases with [r(20)] syndrome indicates that the development is generally normal or mildly delayed but it is followed by cognitive and behavioural decline after seizure onset indicating that the clinical disorder
Ocean Cooling Pattern at the Last Glacial Maximum
Kelin Zhuang,John R. Giardino
Advances in Meteorology , 2012, DOI: 10.1155/2012/213743
Ocean Cooling Pattern at the Last Glacial Maximum
Kelin Zhuang,John R. Giardino
Advances in Meteorology , 2012, DOI: 10.1155/2012/213743
Abstract: Ocean temperature and ocean heat content change are analyzed based on four PMIP3 model results at the Last Glacial Maximum relative to the prehistorical run. Ocean cooling mostly occurs in the upper 1000?m depth and varies spatially in the tropical and temperate zones. The Atlantic Ocean experiences greater cooling than the rest of the ocean basins. Ocean cooling is closely related to the weakening of meridional overturning circulation and enhanced intrusion of Antarctic Bottom Water into the North Atlantic. 1. Introduction The cooling at the Last Glacial Maximum has been extensively studied geologically and numerically (e.g., [1–5]) where proxy data and numerical modeling were both employed to explore the climate sensitivity and mechanism. The Paleoclimate Modeling Intercomparison Project (PMIP2) presented large-scale features (e.g., [6]). However, the spatial pattern of cooling at that period was little studied previously. In this paper we use the newly released PMIP3 data to study the cooling pattern at the Last Glacial Maximum. 2. Methods We analyze ocean potential temperature anomaly, ocean heat content (OHC) change, and meridional overturning mass stream function based on four available PMIP3 models of IPSL-CM5A-LR, MIROC-ESM, MPI-ESM-P, and MRI-CGCM3 so far (http://cmip-pcmdi.llnl.gov/cmip5/), which follow the PMIP3 21ka experimental design (Table 1; http://pmip3.lsce.ipsl.fr/) and make a comparison between the last 50 years of Last Glacial Maximum (LGM) experiments relative to the base period of the last 50 years of the preindustrial control run. Table 1: PMIP3 LGM models. We calculate the temperature anomaly, meridional overturning mass stream function anomaly, and ocean heat content change of each model by regridding all the temperature data into a common grid. 3. Results 3.1. Geographical Distribution Ocean cooling shows pronounced spatial variations (Figure 1), both horizontally and vertically. The Northern Hemisphere exhibits a stronger cooling than the Southern Hemisphere of IPSL-CM5A-LR, MIROC-ESM, and MPI-ESM-P except MRI-CGCM3 with stronger cooling in the Southern Ocean revealing a notable north-south asymmetry. Figure 1: Geographical distribution of potential temperature anomaly in °C at different water depths. The abscissa is longitude in degrees and the ordinate is latitude in degrees. See text for detailed description. At the surface (Figures 1(a) and 1(b)), significant ocean cooling (<?5°C) occurs in the North Pacific and North Atlantic of the first three models. All these three models have shown the maximum cooling regions in the
Lie $3-$algebra and super-affinization of split-octonions
Sergio Giardino,Hector L. Carrion
Physics , 2010, DOI: 10.1142/S0217732311037005
Abstract: The purpose of this study is to extend the concept of a generalized Lie $3-$ algebra, known to the divisional algebra of the octonions $\mathbb{O}$, to split-octonions $\mathbb{SO}$, which is non-divisional. This is achieved through the unification of the product of both of the algebras in a single operation. Accordingly, a notational device is introduced to unify the product of both algebras. We verify that $\mathbb{SO}$ is a Malcev algebra and we recalculate known relations for the structure constants in terms of the introduced structure tensor. Finally we construct the manifestly super-symmetric $\mathcal{N}=1\;\mathbb{SO}$ affine super-algebra. An application of the split Lie $3-$algebra for a Bagger and Lambert gauge theory is also discussed.
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