898 research outputs found
Minimal Flavor Violation and SU(5)-unification
Minimal Flavour Violation in its strong or weak versions, based on
and respectively, allows suitable extensions of the Standard Model at
the TeV scale to comply with current flavour constraints in the quark sector.
Here we discuss considerations analogous to MFV in the context of
-unification, showing the new effects/constraints that arise both in the
quark as in the lepton sector, where quantitative statements can be made
controlled by the CKM matrix elements. The case of supersymmetry is examined in
detail as a particularly motivated example. Third generation sleptons and
neutralinos in the few hundred GeV range are shown to be compatible with
current constraints.Comment: 16 pages, 5 figure
Crystalline realizations of 1-motives
We consider the crystalline realization of Deligne's 1-motives in positive
characteristics and prove a comparison theorem with the De Rham realization of
liftings to zero characteristic. We then show that one dimensional crystalline
cohomology of an algebraic variety, defined by universal cohomological descent
via de Jong's alterations, coincide with the crystalline realization of the
(cohomological) Picard 1-motive, over perfect fields.Comment: 54 pages, exposition improved, references & appendix adde
Frailty and elderly in urology: Is there an impact on post-operative complications?
INTRODUCTION:
Frailty used as predictive tool is still not carried out in daily practice, although many studies confirm the great clinical importance of the frailty syndrome in surgical outcomes. There is no standardized method of measuring the physiological reserves of older surgical patients. The aim of this study was to analyze a cohort of older urological patients according to various frailty indices, in order to evaluate whether they are predictors of post-operative complications after urological procedures.
MATERIAL AND METHODS:
This is a prospective observational study on 78 consecutive older ( 6570 years) patients, subjected to major urological (both endoscopic and 'open surgical') procedures. Frailty was defined according to the Edmonton Frail Scale. Several risk models and biochemical parameters were evaluated. Post-operative outcomes were surgical and medical complications, mortality and rehospitalisation within 3 months.
RESULTS:
An overall prevalence of frailty of 21.8% was found. Patients with complications were frailer than those without complications (univariate analysis), considering both total patients (p = 0.002) and endoscopic (p = 0.04) and 'open surgical' patients (p = 0.013). However, in multivariate analysis, a significant correlation was not found between all frailty indices tested and the risk of major complications. Limitation of the study: the small sample size (lack of statistical power), although this is a prospective study focused on older urological patients.
CONCLUSIONS:
New urology-tailored pre-operative assessment tools may prove beneficial when calculating the risks/benefits of urological procedures, so that objective data can guide surgical decision- making and patient counselling. Further large clinical studies specifically focusing on elderly in urology will be needed
Preliminary data validation and reconstruction of temperature and precipitation in Central Italy
This study assesses the method of data validation of temperature and precipitation in Middle Italy. The procedure proposes a method of validation that may be applied worldwide, provided that calibration relative to the respective climate zones is worked out. The method performs data validation by considering that historical time series show different types of errors such as typing, sensor and reading/recording errors. It takes also into account the procedures for data validation as prescribed by the World Meteorological Organization, implementing them with five types of controls: gross error checking, internal consistency check, tolerance test, temporal consistency and spatial consistency. This work contributes to the development of different standardized methodologies for each type of control to validate climate data; it also provides an innovative procedure to reconstruct missing data in absence of reliable reference time series. The outcomes of this method have led to the removal of 375 records (0.02%) of temperature data from 40 weather stations and 1286 records (1.67%) of precipitation data from 118 weather stations
Cecal Endometriosis as a Cause of Ileocolic Intussusception
Discussed in this report is the use of imaging modalities to aid in the preoperative diagnosis and localization of pathology in this rare condition treated with laparoscopic hemicolectomy
Motivic periods and Grothendieck arithmetic invariants
We construct a period regulator for motivic cohomology of an algebraic scheme over a subfield of the complex numbers. For the field of algebraic numbers we formulate a period conjecture for motivic cohomology by saying that this period regulator is surjective. Showing that a suitable Betti\u2013de Rham realization of 1-motives is fully faithful we can verify this period conjecture in several cases. The divisibility properties of motivic cohomology imply that our conjecture is a neat generalization of the classical Grothendieck period conjecture for algebraic cycles on smooth and proper schemes. These divisibility properties are treated in an appendix by B. Kahn (extending previous work of Bloch and Colliot-Th\ue9l\ue8ne\u2013Raskind)
The Role of Regulatory Agencies in AgendaâSetting Processes: Insights from the Italian Response to the COVIDâ19 Infodemic
International organizations such as the WHO have worked to raise awareness of the massive infodemic that accompanied the COVIDâ19 outbreak and made it hard for people to find trustworthy sources of information and reliable guidance for their decisions. Our contribution focuses on the Italian case, where the Communications Regulatory Authority (AGCOM) was able to act as first mover in its field so as to strategically frame the problem of disinformation in the absence of a preâexisting policy intervention. An emerging body of research shows that the activity of formally independent regulators is not necessarily limited to the implementation of delegated regulatory competencies. We discuss the implications of the activity of independent regulators for the fight against disinformation during the COVIDâ19 pandemic. We find that as a political actor in its own right, the Italian media regulator claimed control over sectoral expertise in order to shape the crucial first steps of the response to the infodemic
Anomalous Weak Values and the Violation of a Multiple-measurement Leggett-Garg Inequality
Quantum mechanics presents peculiar properties that, on the one hand, have
been the subject of several theoretical and experimental studies about its very
foundations and, on the other hand, provide tools for developing new
technologies, the so-called quantum technologies. The nonclassicality pointed
out by Leggett-Garg inequalities has represented, with Bell inequalities, one
of the most investigated subject. In this letter we study the connection of
Leggett-Garg inequalities with a new emerging field of quantum measurement, the
weak values. In particular, we perform an experimental study of the four-time
correlators Legget-Garg test, by exploiting single and sequential weak
measurements performed on heralded single photons. We show violation of a
four-parameters Leggett-Garg inequality in different experimental conditions,
demonstrating an interesting connection between Leggett-Garg inequality
violation and anomalous weak values
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