Quadratic form theory over preordered von Neumann-regular rings

AbstractTo each pair, 〈R,T〉, consisting of a unitary commutative von Neumann-regular ring, R, where 2 is a unit and T is a preorder on R, we associate a reduced special group, GT(R), which faithfully reflects quadratic form theory, modulo T, over free R-modules and then show, using the representation of R as the ring of global sections of its affine scheme, together with results from [M. Dickmann, F. Miraglia, On quadratic forms whose total signature is zero mod 2n. Solution to a problem of M. Marshall, Invent. Math. 133 (1998) 243–278; M. Dickmann, F. Miraglia, Lam's Conjecture, Algebra Colloq. 10 (2003) 149–176; M. Dickmann, F. Miraglia, Algebraic K-theory of special groups, J. Pure Appl. Algebra 204 (2006) 195–234], that GT(R) satisfies a powerful K-theoretic property, the [SMC]-property. From this we conclude that quadratic form theory modulo T over free R-modules verifies Marshall's signature conjecture, Lam's conjecture, as well as a reduced version of Milnor's Witt ring conjecture

Orders and Relative Pythagorean Closures

Orders and Relative Pythagorean Closure

Ocular manifestations in Gorlin-Goltz syndrome

Background: Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients. Results: Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients. Conclusions: The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients

The benefit of permanent monitoring for seismic emergency management

In this paper, a framework based on Value of Information (VoI) theory from pre-posterior Bayesian decision analysis is applied to the case of post-earthquake emergency management of traffic restrictions for a bridge. The decision context is the following: the operator of a bridge is concerned about the use of the structure in post-earthquake scenarios and wishes to know if it is worth to install a Structural Health Monitoring (SHM) system which gives information about the state of the bridge. The possible choices about traffic restrictions after the seismic event are Open or Close the bridge. The benefit of SHM is computed based on VoI and the influence of significant variables involved in the decisional framework is investigated

Self help groups in a city of Tuscany: Reconstruction of the second generation model of work for professionals and services

This study is part of a more extensive project aimed to investigate the effectiveness of self-help group participation in improving quality of life in mental disease. The study is taking place in the Tuscany Region, in Italy. In the first qualitative step of analysis researchers are interested in describing the specific features of the psychiatric self-help movement in Tuscany, comparing different realities, networks, kind of groups. Therefore, our aim is to collect exhaustive information to describe how self-help system work in different provinces at the present moment. The implementation of groups for psychiatric problems is quite young in Italy.  Because of a lack of specific regulation in the directives of the Italian health care system, every local service has implemented groups differently, sometimes enhancing, sometimes dismissing them. Prato, near Florence, is one of the more interesting context for the birth of psychiatric self-help movement in the region: public health services improved groups since early 90’s, it was one of the first self-help reality linked to services in the entire region. Now we are in a “second generation” of professionals, and the original meaning of groups seems to be transformed, sometimes misunderstood. Our objectives of study head us toward an in depth analysis of self-help phenomenon in Prato

Self help groups in a city of Tuscany: Reconstruction of the second generation model of work for professionals and services

This study is part of a more extensive project aimed to investigate the effectiveness of self-help group participation in improving quality of life in mental disease. The study is taking place in the Tuscany Region, in Italy. In the first qualitative step of analysis researchers are interested in describing the specific features of the psychiatric self-help movement in Tuscany, comparing different realities, networks, kind of groups. Therefore, our aim is to collect exhaustive information to describe how self-help system work in different provinces at the present moment. The implementation of groups for psychiatric problems is quite young in Italy.  Because of a lack of specific regulation in the directives of the Italian health care system, every local service has implemented groups differently, sometimes enhancing, sometimes dismissing them. Prato, near Florence, is one of the more interesting context for the birth of psychiatric self-help movement in the region: public health services improved groups since early 90’s, it was one of the first self-help reality linked to services in the entire region. Now we are in a “second generation” of professionals, and the original meaning of groups seems to be transformed, sometimes misunderstood. Our objectives of study head us toward an in depth analysis of self-help phenomenon in Prato

Two Gap State Density in MgB2_{2}: A True Bulk Property or A Proximity Effect?

We report on the temperature dependence of the quasiparticle density of states (DOS) in the simple binary compound MgB2 directly measured using scanning tunneling microscope (STM). To achieve high quality tunneling conditions, a small crystal of MgB2 is used as a tip in the STM experiment. The ``sample'' is chosen to be a 2H-NbSe2 single crystal presenting an atomically flat surface. At low temperature the tunneling conductance spectra show a gap at the Fermi energy followed by two well-pronounced conductance peaks on each side. They appear at voltages V$_{S}\simeq \pm 3.8$ mV and V$_{L}\simeq \pm 7.8$ mV. With rising temperature both peaks disappear at the Tc of the bulk MgB2, a behavior consistent with the model of two-gap superconductivity. The explanation of the double-peak structure in terms of a particular proximity effect is also discussed.Comment: 4 pages, 3 figure

COVID-19 Pneumonia in Children: From Etiology to Management

COVID-19 is less serious in children than in adults. However, respiratory management dominates the clinical picture of hospitalized COVID-19 even in children. In some case series, deterioration of the clinical picture wherein dyspnea, cyanosis, and the onset of acute respiratory distress syndrome (ARDS) emerged ~8–10 days after the onset of SARS-CoV-2 infection, which could rapidly progress to multiple organ failure and death. This review aimed to evaluate the characteristics of COVID-19 pneumonia in pediatric populations, beginning from its etiology and pathological mechanisms and closing with its clinical management

Hydroxyindole-O-methyltransferase (HIOMT) activity in the retina of melatonin-proficient mice

Numerous pieces of evidence support the expression by the mammalian retina of Hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4), the enzyme directly responsible for the biosynthesis of the pineal chronobiotic hormone melatonin (MLT). However, conflicting results obtained so far by enzyme-kinetic and immune-detection techniques still make HIOMT presence and relevance in the eye a matter of debate. This work aimed at evaluating unambiguously HIOMT activity in the mouse retina, a valuable model for studying the effects of MLT variations on ocular pathophysiology. Since laboratory mouse strains can bear genetic polymorphisms yielding defective enzymes of MLT biosynthesis, retinas and control pineal glands used in this study were obtained in a MLT-proficient crossing of A/J mice, the A/J/C57BL/10 strain. To improve the radiochemical reference assay, we tested different homogenization procedures coupled with HPLC detection. Concomitantly, we quantified MLT, and its precursor N-acetyl-serotonin (NAS) by HPLC coupled to electrochemical detection in retinas isolated from either light- or dark-adapted mice. Results showed that the standard radio-chemical assay was successful for pineal HIOMT only, whereas specific homogenization buffers and HPLC were required to detect retinal activity, presumably due to interfering methyl-transferases inhibited by NAS. Under present conditions, retinal HIOMT Vmax accounted for by ≈ 40 fmol/h/mg protein, 2.6-hundreds-fold lower than the pineal counterpart, displaying equivalent KMs (≈10 μM). Moreover, NAS and MLT rapidly decreased in light-exposed isolated retinas, corroborating light-sensitive in-situ MLT formation. Conclusively, we measured mouse retinal HIOMT kinetics under basal conditions, a useful result to elucidate the regulatory patterns, the possible impact on eye health, and therapeutic approaches related to this enzyme