Revised Canonical Quantum Gravity via the Frame Fixing

We present a new reformulation of the canonical quantum geometrodynamics, which allows to overcome the fundamental problem of the frozen formalism and, therefore, to construct an appropriate Hilbert space associate to the solution of the restated dynamics. More precisely, to remove the ambiguity contained in the Wheeler-DeWitt approach, with respect to the possibility of a (3 + 1)-splitting when the space-time is in a quantum regime, we fix the reference frame (i.e. the lapse function and the shift vector) by introducing the so-called kinematical action; as a consequence the new super-Hamiltonian constraint becomes a parabolic one and we arrive to a Schroedinger-like approach for the quantum dynamics. In the semiclassical limit our theory provides General Relativity in the presence of an additional energy-momentum density contribution coming from no longer zero eigenvalues of the Hamiltonian constraints; the interpretation of these new contributions comes out in natural way as soon as it is recognized that the kinematical action can be recasted in such a way it describes a pressureless, but, in general, non geodesic perfect fluid.Comment: 24 pages, 0 figures, to appear on Int. Jour. Mod. Phys.

Dark Matter Prediction from Canonical Quantum Gravity with Frame Fixing

We show how, in canonical quantum cosmology, the frame fixing induces a new energy density contribution having features compatible with the (actual) cold dark matter component of the Universe. First we quantize the closed Friedmann-Robertson-Walker (FRW) model in a sinchronous reference and determine the spectrum of the super-Hamiltonian in the presence of ultra-relativistic matter and a perfect gas contribution. Then we include in this model small inhomogeneous (spherical) perturbations in the spirit of the Lemaitre-Tolman cosmology. The main issue of our analysis consists in outlining that, in the classical limit, the non-zero eigenvalue of the super-Hamiltonian can make account for the present value of the dark matter critical parameter. Furthermore we obtain a direct correlation between the inhomogeneities in our dark matter candidate and those one appearing in the ultra-relativistic matter.Comment: 5 pages, to appear on Modern Physics Letters

Explicit finite element implementation of a shape memory alloy constitutive model and associated analyses

Shape memory alloys (SMA) represent an important class of smart metallic materials employed in various innovative applications thanks to their unique thermomechanical behavior. Since the 1980s, several SMA constitutive models have been proposed and implemented into both commercial and academic finite element analysis software tools. Such models have demonstrated their reliability and robustness in the design and optimization of a wide variety of SMA-based components. However, most models are implemented using implicit integration schemes, thus limiting their applicability in highly nonlinear analyses. The objective of this work is to present a novel explicit integration scheme for the numerical implementation of the three-dimensional Souza-Auricchio model, a phenomenological model able to reproduce the primary SMA responses (i.e., pseudoelasticity and shape memory effect). The model constitutive equations are formulated by adopting the continuum thermodynamic theory with internal variables, following a plasticity-like approach. An elastic predictor-inelastic corrector scheme is here used to solve the time-discrete non-linear constitutive equations in the explicit framework. The proposed algorithm is investigated through several benchmark boundary-value problems of increasing complexity, considering both pseudoelastic and shape memory response in quasi-static conditions; a comparison with an implicit integration scheme is also performed. Such numerical tests demonstrate the ability of the algorithm to reproduce key material behaviors with effectiveness and robustness. Particularly, the analysis of SMA cables demonstrates the effectiveness of the explicit algorithm to solve complex problems involving widespread nonlinear contact, which prevent the convergence of the implicit scheme. Details such as mass-scaling options are also discussed

FATHERHOOD AND MASCULINITY

The thesis presents the results of a qualitative social research which deals with contemporary experiences and representations of fatherhood in the Italian context, with the main aim of looking at possible spaces for a deepening of the reflection on how studying fatherhood could give a contribution to the study of masculinities. Theoretically, it is based on the conceptual distinction between fathers, fathering and fatherhood, on conceptualizations of masculinities, and on critiques and developments of the concept of hegemonic masculinity: hybrid/plural masculinities on the one hand and inclusive/caring masculinities on the other. Methodologically, it is based on three sets of data: 33 discursive interviews with first time Italian fathers of children aged 0-3 years, all employed, heterosexual, and cohabiting with the mothers of their children (areas of Torino and Cuneo \u2013 Piedmont); 15 television advertisements depicting fathers, and a focus group with a subgroup of interviewees on media representations of fatherhood and issues related to care. The analysis of the empirical materials deals with different issues: the process of becoming a father, and the meanings attached to fatherhood; care practices and responsibilities; fatherhood as depicted in popular media culture; gender costruction in fathering practices. The fundamental aim is to understand whether contemporary experiences of fatherhood and transformations of traditional masculinities may represent a change in gender relations within the family, or instead have to be interpreted as hybridizations of hegemonic masculinity

Genetic therapies for inherited neuromuscular disorders

Inherited neuromuscular disorders encompass a broad group of genetic conditions, and the discovery of these underlying genes has expanded greatly in the past three decades. The discovery of such genes has enabled more precise diagnosis of these disorders and the development of specific therapeutic approaches that target the genetic basis and pathophysiological pathways. Such translational research has led to the approval of two genetic therapies by the US Food and Drug Administration: eteplirsen for Duchenne muscular dystrophy and nusinersen for spinal muscular atrophy, which are both antisense oligonucleotides that modify pre-mRNA splicing. In this Review we aim to discuss new genetic therapies and ongoing clinical trials for Duchenne muscular dystrophy, spinal muscular atrophy, and other less common childhood neuromuscular disorders

Dystonia: sparse synapses for D2 receptors in striatum of a DYT1 knock-out mouse model

Dystonia pathophysiology has been partly linked to downregulation and dysfunction of dopamine D2 receptors in striatum. We aimed to investigate the possible morpho-structural correlates of D2 receptor downregulation in the striatum of a DYT1 Tor1a mouse model. Adult control Tor1a+/+ and mutant Tor1a+/− mice were used. The brains were perfused and free-floating sections of basal ganglia were incubated with polyclonal anti-D2 antibody, followed by secondary immune-fluorescent antibody. Confocal microscopy was used to detect immune-fluorescent signals. The same primary antibody was used to evaluate D2 receptor expression by western blot. The D2 receptor immune-fluorescence appeared circumscribed in small disks (~0.3–0.5 μm diameter), likely representing D2 synapse aggregates, densely distributed in the striatum of Tor1a+/+ mice. In the Tor1a+/− mice the D2 aggregates were significantly smaller (μm2 2.4 ± SE 0.16, compared to μm2 6.73 ± SE 3.41 in Tor1a+/+) and sparse, with ~30% less number per microscopic field, value correspondent to the amount of reduced D2 expression in western blotting analysis. In DYT1 mutant mice the sparse and small D2 synapses in the striatum may be insufficient to “gate” the amount of presynaptic dopamine release diffusing in peri-synaptic space, and this consequently may result in a timing and spatially larger nonselective sphere of influence of dopamine action

Embolisation for Vascular Injuries Complicating Elective Orthopaedic Surgery

AbstractObjectivesThe study aims to present the indications and emphasise the role of embolisation for vascular injuries in orthopaedic surgery.MethodsThirty-one patients with vascular injuries complicating elective orthopaedic surgery had embolisation from 2003 to 2010. N-2-butyl cyano-acrylate (NBCA) was used as embolic agent in 28 patients, gelatin sponge in three and coil embolisation in addition to NBCA or gelatin sponge in two patients. The mean follow-up period was 37 months (range, 4–96 months).ResultsThe most common orthopaedic operations associated with vascular injuries amenable to embolisation were hip-joint procedures; and the most common injuries were arterial tears of branch vessels or non-critical axial vessels, most commonly of the superior glutaeal artery. In all cases, angiography showed the bleeding point, and a single embolisation session effectively stopped bleeding. Embolisation-related complications were not observed.ConclusionsEmbolisation should be considered the treatment of choice for vascular injuries of branch vessels or non-critical axial vessels following elective orthopaedic surgery because of the advantages of minimally invasive therapy and the lack of complications

The NorthStar Ambulatory Assessment in Duchenne muscular dystrophy: considerations for the design of clinical trials.

With the emergence of experimental therapies for Duchenne muscular dystrophy (DMD), it is fundamental to understand the natural history of this disorder to properly design clinical trials. The aims of this study were to assess the effects produced on motor function by different DMD genotypes and early initiation of glucocorticoids

Humans and Water in Desert “Refugium” Areas: Palynological Evidence of Climate Oscillations and Cultural Developments in Early and Mid-Holocene Saharan Edges

Saharan anthropic deposits from archaeological sites, located along wadis or close to lakes, and sedimentary sequences from permanent and dried basins demonstrate that water has always been an attractive environmental feature, especially during periods of drought. This paper reports on two very different examples of Holocene sites where “humans and water” coexisted during dry periods, as observed by stratigraphic, archaeological and palynological evidence. Independent research was carried out on the Jefara Plain (Libya, 32°N) and the Gobero area (Niger, 17°N), at the extreme northern and southern limits of the Sahara, respectively. The histories of the Jefara and Gobero areas, as revealed by the archaeological and palaeoenvironmental reconstructions, suggest that these areas were likely to have been visited and exploited for a long time, acting as anthropic refugia, and therefore they have been profoundly transformed. Human presence and actions have conditioned the local growing of plants and selected a more or less synanthropic flora. Today, modern conservation strategies should take into consideration that water reservoirs, which are crucial for the long-term conservation of biodiversity, have provided refugia in the past just as they presently do under global warming conditions