Suggestions for Radiation Oncologists during the COVID-19 Pandemic

SARS-CoV-2 pandemic and COVID-19 diffusion have recently become an international public health emergency. Cancer patients, as a frail population, are particularly exposed to the risk related to infections. The clinical decision-making process and the organizational workflow of radiotherapy department should be revised in the light of the critical situation. We herein provide practical suggestions derived from the available literature and discussed during an online session held within the e-learning educational program of the European School of Oncology on March 31st 2020

Spatio-temporal vortex beams and angular momentum

We present a space-time generalization of the known spatial (monochromatic) wave vortex beams carrying intrinsic orbital angular momentum (OAM) along the propagation direction. Generic spatio-temporal vortex beams are polychromatic and can carry intrinsic OAM at an arbitrary angle to the mean momentum. Applying either (i) a transverse wave-vector shift or (ii) a Lorentz boost to a monochromatic Bessel beam, we construct a family of either (i) time-diffracting or (ii) non-diffracting spatio-temporal Bessel beams, which are exact solutions of the Klein-Gordon wave equations. The proposed spatio-temporal OAM states are able to describe either photon or electron vortex states (both relativistic and nonrelativistic), and can find applications in particle collisions, optics of moving media, quantum communications, and astrophysics.Comment: 9 pages, 6 figures, to appear in Phys. Rev.

Correcting for the Effects of Interstellar Extinction

This paper addresses the issue of how best to correct astronomical data for the wavelength-dependent effects of Galactic interstellar extinction. The main general features of extinction from the IR through the UV are reviewed, along with the nature of observed spatial variations. The enormous range of extinction properties found in the Galaxy, particularly in the UV spectral region, is illustrated. Fortunately, there are some tight constraints on the wavelength dependence of extinction and some general correlations between extinction curve shape and interstellar environment. These relationships provide some guidance for correcting data for the effects of extinction. Several strategies for dereddening are discussed along with estimates of the uncertainties inherent in each method. In the Appendix, a new derivation of the wavelength dependence of an average Galactic extinction curve from the IR through the UV is presented, along with a new estimate of how this extinction law varies with the parameter R = A(V)/E(B-V). These curves represent the true monochromatic wavelength dependence of extinction and, as such, are suitable for dereddening IR--UV spectrophotometric data of any resolution, and can be used to derive extinction relations for any photometry system.Comment: To appear in PASP (January 1999) 14 pages including 4 pages of figures Uses emulateapj style. PASP, in press (January 1999

Wigner Crystal State for the Edge Electrons in the Quantum Hall Effect at Filling ν=2\nu = 2

The electronic excitations at the edges of a Hall bar not much wider than a few magnetic lengths are studied theoretically at filling $\nu = 2$. Both mean-field theory and Luttinger liquid theory techniques are employed for the case of a null Zeeman energy splitting. The first calculation yields a stable spin-density wave state along the bar, while the second one predicts dominant Wigner-crystal correlations along the edges of the bar. We propose an antiferromagnetic Wigner-crystal groundstate for the edge electrons that reconciles the two results. A net Zeeman splitting is found to produce canting of the antiferromagnetic order.Comment: 22 pgs. of PLAIN TeX, 1 fig. in postscript, published versio

Eating and feeding disorders in pediatric age

Eating and feeding disorders are common in pediatric age and may be important to discover and recover the early symptoms in order to optimize the treatment and management

Psychopathological and psychodynamic hypotheses for pediatric stuttering

Stuttering is a common language alteration in pediatric age consisting in repetitions and blocks, which entail a break in the rhythm and melody of the speech. According to the WHO it is a disorder of the rhythm of the word, the subject knows precisely what he would like to say, but at the same time he is not able to say it. It is a great inconvenience for those affected, also because the slowing down of speaking is not about thought or cognitive skills

Phonon Squeezed States Generated by Second Order Raman Scattering

We study squeezed states of phonons, which allow a reduction in the quantum fluctuations of the atomic displacements to below the zero-point quantum noise level of coherent phonon states. We investigate the generation of squeezed phonon states using a second order Raman scattering process. We calculate the expectation values and fluctuations of both the atomic displacement and the lattice amplitude operators, as well as the effects of the phonon squeezed states on macroscopically measurable quantities, such as changes in the dielectric constant. These results are compared with recent experiments.Comment: 4 pages, REVTE

Aspects of the methodology validation for light filth in fruit pulp

Methodology validation is an important tool to support the activities of metrology in the quantification analysis. Extraneous materials may be present in the pulps due to the conditions or the practices of production, storage and distribution. Since there is no specific methodology for fruit pulp light filth quantification a research has been carried out to test two methods for isolation of light filth in mango, strawberry, tomato and guava pulps. For guava, mango and tomato pulps the AOAC Official Method 964.23 was used, and for strawberry pulp AOAC Official Method 950.89, with adaptations. The micro-analytic standard for insect fragment and rodent hair was prepared in the laboratory. The study has been conducted on 63 samples of 100 g of pulp analyzed in duplicate after contamination with 5, 15, 30 insect fragments (IF) per 100 g and 5, 10, 15 rodent hair (RH) per 100 g, with blank samples as a control. The validation parameters used were precision and accuracy. Recovery of insect fragment was considered stisfactory in mango, tomato, guava pulps, and the average recovery ranged from 87 to 96%. For strawberry pulp, the recovery rate ranged from 68 to 80%. For rodent hairs, the best recovery rate was observed in mango pulp ranging from 73 to 81%, followed by guava pulp ranging from 65 to 76%, tomato pulp ranging from 50 to 67%, and strawberry pulp ranging from 33 to 35%. It was concluded that the methodologies used to detect light filth in guava, mango, tomato and strawberry pulps can be adopted in the monitoring routine of fruit pulp extraneous material contamination even though they were found not very efficient for rodent hairs. Keywords: Insect fragment, Rodent hair, AOAC determination method, Recovery rate, Fruit pulp