Search results for "Normal"

The renormalized electron mass in non-relativistic quantum electrodynamics

2007

This work addresses the problem of infrared mass renormalization for a scalar electron in a translation-invariant model of non-relativistic QED. We assume that the interaction of the electron with the quantized electromagnetic field comprises a fixed ultraviolet regularization and an infrared regularization parametrized by $\sigma>0$. For the value $p=0$ of the conserved total momentum of electron and photon field, bounds on the renormalized mass are established which are uniform in $\sigma\to0$, and the existence of a ground state is proved. For $|p|>0$ sufficiently small, bounds on the renormalized mass are derived for any fixed $\sigma>0$. A key ingredient of our proofs is the operator-t…

Structural and vibrational study of the tautomerism of histamine free-base in solution.

2003

Infrared and Raman spectroscopy in H(2)O and D(2)O and quantum Density Functional calculations were used to determine the structure of histamine free-base in aqueous solution. A quantum mechanical study of the tautomeric equilibrium of histamine free-base in solution was performed at the 6-311G level. Electronic correlation energies were included by using the hybrid functional B3LYP. The solvent was simulated as a continuum characterized by a dielectric constant, and the quantum system (solute) was placed in an ellipsoidal cavity. Solute-solvent electrostatic interaction was calculated by means a multipolar moment expansion introduced in the Hamiltonian. Four relevant histamine conformation…

High order normal form construction near the elliptic orbit of the Sitnikov problem

2011

We consider the Sitnikov problem; from the equations of motion we derive the approximate Hamiltonian flow. Then, we introduce suitable action–angle variables in order to construct a high order normal form of the Hamiltonian. We introduce Birkhoff Cartesian coordinates near the elliptic orbit and we analyze the behavior of the remainder of the normal form. Finally, we derive a kind of local stability estimate in the vicinity of the periodic orbit for exponentially long times using the normal form up to 40th order in Cartesian coordinates.

EFFECT OF THE IMPase INHIBITOR L690,330 ON SEA URCHIN DEVELOPMENT

1998

Abstract A variety of concentrations of the IMPase inhibitor L690,330 were added to sea urchin embryos. Immediate arrest of development was obtained for concentrations from 7.5 m m on. Concentrations lower than 3.5 m m permitted gastrulation but inhibited skeletogenesis and disturbed elongation along the animal–vegetal axis. The latter results are similar to those obtained by counteracting lithium effect with myoinositol, which are suggested to be due to partial relief of IMPase inhibition.

Developmental terms—some proposals: First report of an International working group

1979

Paper 6: EUROCAT member registries: organization and activities.

2011

BACKGROUND: EUROCAT is a network of population-based congenital anomaly registries providing standardized epidemiologic information on congenital anomalies in Europe. There are three types of EUROCAT membership: full, associate, or affiliate. Full member registries send individual records of all congenital anomalies covered by their region. Associate members transmit aggregate case counts for each EUROCAT anomaly subgroup by year and by type of birth. This article describes the organization and activities of each of the current 29 full member and 6 associate member registries of EUROCAT. METHODS: Each registry description provides information on the history and funding of the registry, popu…

Fetal Urogenital Sinus with Consecutive Hydrometrocolpos because of Labial Fusion: Prenatal Diagnostic Difficulties and Postpartal Therapeutic Manage…

2006

<i>Objective:</i> To elucidate the differential diagnoses of tumorous dilations in the fetal pelvic region detected by prenatal ultrasound and the postnatal management demonstrated on a fetus with 29 weeks of gestation with a retrovesical located bottle-like cystic structure measuring 54 × 31 × 27 mm within the pelvis. Postnatal findings were a labial fusion and a consecutive hydrometrocolpos due to a urethrovaginal fistula. <i>Method:</i> Case report of a fetus affected by an intricate cloacal anomaly. <i>Results:</i> The long-term prognosis for this nonsyndromic form of hydrometrocolpos without any other structural defects or organic failures after oper…

Comparison Between Fractional Vegetation Cover Retrievals from Vegetation Indices and Spectral Mixture Analysis: Case Study of PROBA/CHRIS Data Over …

2009

Abstract: In this paper we compare two different methodologies for Fractional Vegetation Cover (FVC) retrieval from Compact High Resolution Imaging Spectrometer (CHRIS) data onboard the European Space Agency (ESA) Project for On-Board Autonomy (PROBA) platform. The first methodology is based on empirical approaches using Vegetation Indices (VIs), in particular the Normalized Difference Vegetation Index (NDVI) and the Variable Atmospherically Resistant Index (VARI). The second methodology is based on the Spectral Mixture Analysis (SMA) technique, in which a Linear Spectral Unmixing model has been considered in order to retrieve the abundance of the different constituent materials within pixe…

The effects of muscle mass and muscle quality on cardio-metabolic risk in peripubertal girls: a longitudinal study from childhood to early adulthood.

2017

Increased cardio-metabolic risk is well documented in children and adolescents with obesity and normal weight obesity (NWO). However, the associations of muscle mass and muscle quality with cardio-metabolic risk, independent of weight status from childhood to adulthood, has not been examined. A total of 236 girls were followed from pre-puberty to early adulthood. Fat mass (FM) and lean mass (LM) of the whole body were assessed by a dual-energy X-ray absorptiometry; muscle cross-sectional area (mCSA), muscle density (mDen; skeletal muscle fat content) of the lower leg by the peripheral quantitative computerized tomography; and blood glucose, insulin, triglycerides and high-density lipoprotei…

Non-Gaussian Distribution for Var Calculation: an Assessment for the Italian Market

2001

Abstract In this paper we compare different approaches to computing VaR (Value-at-Risk) for heavy tailed return series. Using data from the Italian market, we show that almost all the return series present statistically significant skewness and kurtosis. We implement (i) the stable models proposed by Rachev et al . (2000), (ii) an alternative to the Gaussian distributions based on a Generalized Error Distribution and (iii) a non-parametric model proposed by Li (1999). All the models are then submitted to backtest on out-of-sample data in order to assess their forecasting power. We observe that when the percentiles are low, all the models tested produce results that are dominant compared to …