The WKB Approximation without Divergences

In this paper, the WKB approximation to the scattering problem is developed without the divergences which usually appear at the classical turning points. A detailed procedure of complexification is shown to generate results identical to the usual WKB prescription but without the cumbersome connection formulas.Comment: 13 pages, TeX file, to appear in Int. J. Theor. Phy

A model independent and rephase invariant parametrization of CP violation

The phenomenological description of the neutral B meson system is proposed in terms of the fundamental CP-violating observables and within a rephasing invariant formalism. This generic formalism can select the time-dependent and time-integrated asymmetries which provide the basic tools to discriminate the different kinds of possible CP-violating effects in dedicated experimental B-meson facilities.Comment: 19 pages, Plain Te

Cooperative photon emission rates in random atomic clouds

We investigate a family of $N\times N$ Euclidean random matrices $S$, whose entries are $\operatorname{sinc}$ functions of the distance between points independently sampled from a Gaussian distribution in three dimensions. This random matrix model arises in the study of cooperative photon emission rates of a random atomic cloud, initially excited by a laser in the linear regime. The spectral properties of $S$, in the large-$N$ limit, strongly depend on the atomic cloud density. We show that in the low-density regime the eigenvalue density of $S$ has a nontrivial limit that only depends on the so-called cooperativeness parameter $b_0$, the only parameter of the model. For small values $b_0\ll1$, we find that the limit eigenvalue density is approximatively triangular. We also study the nearest-neighbour spacing distribution and the eigenvector statistics. We find that, although $S$ is a Euclidean random matrix, the bulk of its spectrum is described by classical random matrix theory. In particular, in the bulk there is level repulsion and the eigenvectors are delocalized. Therefore, the bulk of the spectrum of $S$ exhibits the universal behaviour of chaotic quantum systems.Comment: 14 pages, 8 figure

Rate constants for the reactions of O+ with N2 and O2 as a function of temperature (300–1800 K)

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/106/9/10.1063/1.473450.We have studied the rate constants for the reaction of O+ with N2 over the temperature range 300–1600 K and the reaction of O+ with O2 over the range 300 to 1800 K. The results are in good agreement with previous measurements made up to 900 K. The rate constant for the O+reaction with N2 shows a minimum in the temperature range 1100–1300 K. The increase above this temperature is due to N2 v=2 becoming populated. The rate constant for O++O2 shows a minimum in the 800–1100 K range. Comparing to previous drift tube measurements allows the rate constant for O2 (v>0) to be derived. The v>0 rate constant is approximately five times larger than the v=0 rate constant

Validation of satellite OPEMW precipitation product with ground-based weather radar and rain gauge networks

Abstract. The Precipitation Estimation at Microwave Frequencies (PEMW) algorithm was developed at the Institute of Methodologies for Environmental Analysis of the National Research Council of Italy (IMAA-CNR) for inferring surface rain intensity (sri) from satellite passive microwave observations in the range from 89 to 190 GHz. The operational version of PEMW (OPEMW) has been running continuously at IMAA-CNR for two years. The OPEMW sri estimates, together with other precipitation products, are used as input to an operational hydrological model for flood alert forecast. This paper presents the validation of OPEMW against simultaneous ground-based observations from a network of 20 weather radar systems and a network of more than 3000 rain gauges distributed over the Italian Peninsula and main islands. The validation effort uses a data set covering one year (July 2011–June 2012). The effort evaluates dichotomous and continuous scores for the assessment of rain detection and quantitative estimate, respectively, investigating both spatial and temporal features. The analysis demonstrates 98% accuracy in correctly identifying rainy and non-rainy areas; it also quantifies the increased ability (with respect to random chance) to detect rainy and non-rainy areas (0.42–0.45 Heidke skill score) or rainy areas only (0.27–0.29 equitable threat score). Performances are better than average during summer, fall, and spring, while worse than average in the winter season. The spatial–temporal analysis does not show seasonal dependence except over the Alps and northern Apennines during winter. A binned analysis in the 0–15 mm h−1 range suggests that OPEMW tends to slightly overestimate sri values below 6–7 mm h−1 and underestimate sri above those values. With respect to rain gauges (weather radars), the correlation coefficient is larger than 0.8 (0.9). The monthly mean difference and standard deviation remain within ±1 and 2 mm h−1 with respect to rain gauges (respectively −2–0 and 4 mm h−1 with respect to weather radars)

Mouse tracking to explore motor inhibition processes in go/no-go and stop signal tasks

Response inhibition relies on both proactive and reactive mechanisms that exert a synergic control on goal-directed actions. It is typically evaluated by the go/no-go (GNG) and the stop signal task (SST) with response recording based on the key-press method. However, the analysis of discrete variables (i.e., present or absent responses) registered by key-press could be insufficient to capture dynamic aspects of inhibitory control. Trying to overcome this limitation, in the present study we used a mouse tracking procedure to characterize movement profiles related to proactive and reactive inhibition. A total of fifty-three participants performed a cued GNG and an SST. The cued GNG mainly involves proactive control whereas the reactive component is mainly engaged in the SST. We evaluated the velocity profile from mouse trajectories both for responses obtained in the Go conditions and for inhibitory failures. Movements were classified as one-shot when no corrections were observed. Multi-peaked velocity profiles were classified as non-one-shot. A higher proportion of one-shot movements was found in the SST compared to the cued GNG when subjects failed to inhibit responses. This result suggests that proactive control may be responsible for unsmooth profiles in inhibition failures, supporting a differentiation between these tasks

Impact of COVID-19 Pandemic on Children and Adolescents with Neuropsychiatric Disorders: Emotional/Behavioral Symptoms and Parental Stress

The objective of our study was to evaluate the impact of the COVID-19 pandemic on the emotional and behavioral symptoms in minors with neuropsychiatric disorders and on parental stress through a standardized neuropsychological assessment, comparing the data collected before the pandemic with those collected during the lock-down. Another goal of our study was to analyze the relationship between parental stress and behavioral/emotional symptoms in children. Our study was conducted on 383 families of patients who had already been referred at the Child Neuropsychiatry Unit of the University Hospital of Salerno for different neuropsychiatric conditions. All the parents completed two neuropsychological standardized questionnaires for the assessment of parental stress (PSI—Parenting Stress Index-Short Form) and the emotional/behavioral problems of their children (Child Behaviour CheckList). The data collected during the pandemic were compared with those collected from questionnaires administered during the six months preceding the pandemic, as is our usual clinical practice. The comparison between the mean scores of PSI and CBCL before and after the pandemic showed a statistically significant increase in all subscales analyzed in the total sample. The correlation analysis showed significant positive relationship between the subscale Total Stress of PSI and the subscales Total Problems and Internalizing Problems of CBCL. Our study suggested that the COVID-19 pandemic and the corresponding measures adopted led to an increase in internalizing and externalizing symptoms in children and adolescents with neuropsychiatric disorder. Similarly, parental stress increased during COVID-19 and ahigher level of stress in parents can be related to the internalizing symptoms of their children