Quenched lattice calculation of semileptonic heavy-light meson form factors

We calculate, in the continuum limit of quenched lattice QCD, the matrix elements of the heavy-heavy vector current between heavy-light pseudoscalar meson states. We present the form factors for different values of the initial and final meson masses at finite momentum transfer. In particular, we calculate the non-perturbative correction to the differential decay rate of the process B --> D l nu including the case of a non-vanishing lepton mass.Comment: 16 pages, 10 figures, version accepted for publication on JHE

The continuum limit of the static-light meson spectrum

We investigate the continuum limit of the low lying static-light meson spectrum using Wilson twisted mass lattice QCD with N_f = 2 dynamical quark flavours. We consider three values of the lattice spacing a ~ 0.051 fm, 0.064 fm, 0.080 fm and various values of the pion mass in the range 280 MeV < m_PS < 640 MeV. We present results in the continuum limit for light cloud angular momentum j = 1/2, 3/2, 5/2 and for parity P = +, -. We extrapolate our results to physical quark masses, make predictions regarding the spectrum of B and B_s mesons and compare with available experimental results.Comment: 18 pages, 3 figure

Colour-electric spectral function at next-to-leading order

The spectral function related to the correlator of two colour-electric fields along a Polyakov loop determines the momentum diffusion coefficient of a heavy quark near rest with respect to a heat bath. We compute this spectral function at next-to-leading order, O(alpha_s^2), in the weak-coupling expansion. The high-frequency part of our result (omega >> T), which is shown to be temperature-independent, is accurately determined thanks to asymptotic freedom; the low-frequency part of our result (omega << T), in which Hard Thermal Loop resummation is needed in order to cure infrared divergences, agrees with a previously determined expression. Our result may help to calibrate the overall normalization of a lattice-extracted spectral function in a perturbative frequency domain T << omega << 1/a, paving the way for a non-perturbative estimate of the momentum diffusion coefficient at omega -> 0. We also evaluate the colour-electric Euclidean correlator, which could be directly compared with lattice simulations. As an aside we determine the Euclidean correlator in the lattice strong-coupling expansion, showing that through a limiting procedure it can in principle be defined also in the confined phase of pure Yang-Mills theory, even if a practical measurement could be very noisy there.Comment: 38 page

Non-perturbative renormalization of the static axial current in two-flavour QCD

We perform the non-perturbative renormalization of matrix elements of the static-light axial current by a computation of its scale dependence in lattice QCD with two flavours of massless O(a) improved Wilson quarks. The regularization independent factor that relates any running renormalized matrix element of the axial current in the static effective theory to the renormalization group invariant one is evaluated in the Schroedinger functional scheme, where in this case we find a significant deviation of the non-perturbative running from the perturbative prediction. An important technical ingredient to improve the precision of the results consists in the use of modified discretizations of the static quark action introduced earlier by our collaboration. As an illustration how to apply the renormalization of the static axial current presented here, we connect the bare matrix element of the current to the B_s-meson decay constant in the static approximation for one value of the lattice spacing, a ~ 0.08 fm, employing large-volume N_f=2 data at beta=5.3.Comment: 33 pages including figures and tables, latex2e, uses JHEP3.cls; version published in JHEP, small additions, results unchange

Birth and Death in a Continuous Opinion Dynamics Model. The consensus case

We here discuss the process of opinion formation in an open community where agents are made to interact and consequently update their beliefs. New actors (birth) are assumed to replace individuals that abandon the community (deaths). This dynamics is simulated in the framework of a simplified model that accounts for mutual affinity between agents. A rich phenomenology is presented and discussed with reference to the original (closed group) setting. Numerical findings are supported by analytical calculations.Comment: 13 pages, 6 figure

Maturity-Onset Diabetes of the Young in Children With Incidental Hyperglycemia:: A multicenter Italian study of 172 families

OBJECTIVE - To investigate the prevalence of maturity-onset diabetes of the young (MODY) in Italian children With incidental hyperglycemia. RESEARCH DESIGN AND METHODS - Among 748 subjects age 1-18 years with incidental hyperglycemia, minimal diagnostic criteria for MODY were met by 172 families. Mutational analyses of the glucokinase (GCK) and hepatocyte nuclear factor lot (HNF1A) genes were performed. RESULTS - We identified 85 GCK gene mutations in 109 probands and 10 HNF1A mutations in 12 probands. In GCK patients, the median neonatal weight and age at the first evaluation were lower than those found in patients with HNF1A mutations. Median fasting plasma glucose and impaired fasting glucose/impaired glucose tolerance frequency after oral glucose tolerance testing were higher in GCK patients, who also showed a lower frequency of diabetes than HNF1A patients. CONCLUSIONS - GCK mutations are the prevailing cause of MODY (63.4%) when the index case is recruited in Italian children with incidental hyperglycemia

Contextual influences on italian university students during the covid-19 lockdown: Emotional responses, coping strategies and resilience

none17Based on an ecological perspective on the COVID-19 lockdown experience, this study describes psychological responses among Italian university students. Our study considers three zones of the country that have differed in the intensity of the COVID-19 pandemic. Specifically, this research explores whether differences in pandemic conditions can account for their divergent psychological outcomes. The participants were 792 university students from seven different Italian universities. Students were asked to express their emotions and describe meaningful events during the lockdown in writing. Based on the grounded theory approach, this study conducted qualitative data analysis using ATLAS.ti 8.0. The core emerged categories are emotions, emotional moods and state of mind, coping strategies, and resilience. The results describing these emergent factors in relation to environmental variables highlight differences in the feeling of anxiety among individuals: anxiety was more self-focused in zones that were more affected by the lockdown, while such anxiety was more related to family and friends in less-affected zones. In addition to identifying the negative repercussions that this emergency has had, this study describes some positive outcomes, such as the elaboration of new personal perspectives that help foster individual growth and allow individuals to gain new awareness of themselves and others. The confinement due to the COVID-19 emergency measures has been a very unique experience for people, and further research is needed to understand the long-term effects of the different coping responses activated by participants during and after the lockdown.mixedLaura Migliorini; Norma De Piccoli; Paola Cardinali; Chiara Rollero; Daniela Marzana; Caterina Arcidiacono; Elisa Guidi; Ciro Esposito; Cinzia Novara; Angela Fedi; Elena Marta; Andrea Guazzini; Patrizia Meringolo; Maria Grazia Monaci; Barbara Agueli; Fortuna Procentese; Immacolata Di NapoliMigliorini, Laura; De Piccoli, Norma; Cardinali, Paola; Rollero, Chiara; Marzana, Daniela; Arcidiacono, Caterina; Guidi, Elisa; Esposito, Ciro; Novara, Cinzia; Fedi, Angela; Marta, Elena; Guazzini, Andrea; Meringolo, Patrizia; Grazia Monaci, Maria; Agueli, Barbara; Procentese, Fortuna; Di Napoli, Immacolat

The human penguin project: climate, social integration, and core body temperature

Social thermoregulation theory posits that modern human relationships are pleisiomorphically organized around body temperature regulation. In two studies (N = 1755) designed to test the principles from this theory, we used supervised machine learning to identify social and non-social factors that relate to core body temperature. This data-driven analysis found that complex social integration (CSI), defined as the number of high-contact roles one engages in, is a critical predictor of core body temperature. We further used a cross-validation approach to show that colder climates relate to higher levels of CSI, which in turn relates to higher CBT (when climates get colder). These results suggest that despite modern affordances for regulating body temperature, people still rely on social warmth to buffer their bodies against the cold.info:eu-repo/semantics/publishedVersio