Comparisons of log-normal mixture and Pareto tails, GB2 or log-normal body of Romania's all cities size distribution

Modeling demographic data has been on the agenda of statisticians for many years. Some of the distributions used are Pareto, reverse Pareto, q-exponential and log-normal models. An approach to this problem is to consider three statistical models: one for the upper tail, one for the middle range, and another for the lower tail. This paper deals with the size distribution of urban and rural agglomerations in Romania for the 1992–2017 period, by comparing the recently introduced three log-normal mixture (3LN), Pareto tails log-normal (PTLN), and threshold double Pareto Generalized Beta of second kind (tdPGB2) models. The tdPGB2 statistical model has the PTLN distribution as a limiting case. The maximum likelihood estimates of the distributions are computed, and goodness-of-fit tests are performed using the Kolmogorov–Smirnov (KS), Cramér–von Mises (CM) and Anderson–Darling (AD) statistics. Also, we use the Vuong and Bayes factor log-likelihood tests. Using both graphical and formal statistical tests, our results rigorously confirm that the 3LN model is statistically equivalent to PTLN and tdPGB2 distributions, the preferred model being the PTLN probability law. Both the PTLN and tdPGB2 distributions have Pareto tails but the 3LN model does not. All the three models prove to be very well suited parameterizations of Romania's city size data

Recent environmental changes in the area of La Maddalena Harbour (Sardinia, Italy): data from mollusks and benthic foraminifera

Mollusks and benthic foraminifera are reliable tools to paleo-environmental reconstructions because they commonly occur in most marine habitats and are sensitive to major and short-lived changes of environmental drivers, induced by both natural and anthropogenic events. Their community structure provides useful information about the characteristics of their habitat and some species are sensitive to specific environmental controls. Features such as changes in species composition and community, or variation in test morphology provide evidence of fluctuation of several environmental factors. Therefore, both mollusks and benthic foraminifera can be used as an efficient method for identifying the history and ecological trajectory of marine ecosystems. This study focuses on the macro- (mollusks) and micropaleontological (benthic foraminifera) study of a 3 m long sediment core collected in the former military arsenal of the La Maddalena harbor (N Sardinia, Italy), at a depth of 15 m. The core site is located on the S-E coast of La Maddalena island, that underwent a complex history of human occupation along with natural environmental evolution and human-derived pressures. We aimed to reconstruct the main environmental changes recorded in the fossil benthic communities along the core, and to propose the most likely factors that caused these changes. Both mollusks and benthic foraminifera have been picked from the core, identified at genus/species level and counted. Ecological indications for each species have been extracted from literature. Univariate and multivariate statistics have been applied to highlight the community dynamics. More than 90 species of benthic foraminifera have been identified, and 101 mollusk species (846 specimens). The foraminifera diversity indices show a general reduction from the first 50 cm downcore. This slight decline is accompanied by changes in foraminiferal assemblages. The results concerning changes in foraminiferal species composition, their abundance and biodiversity, supported by statistical analyses (cluster analysis), allowed identification of three major foraminiferal associations corresponding to different marine coastal settings. The same results have been obtained by using mollusks and their ecological significance in the framework of benthic marine bionomics. Species are related to infralittoral vegetated bottom such as Posidonia meadows (HP) or photophilous algae through the core, but with variation in percentage of abundance, and HP species decreases from the bottom to the top, whereas species related to muddy bottom follow the opposite trend (coastal detritic mud, deep mud). This testifies that the area underwent a progressive reduction of Posidonia meadows and light-loving algae with a shift toward muddy bottoms, possibly related to the effect of the intensive renovation works of the harbor area. Moreover, radiocarbon dating obtained from Cerithium specimens indicated that the sedimentation rate increases in the upper portion of the core, according to the ecological signal reconstructed by the analysis of the mollusk assemblage

Adaptive estimation in circular functional linear models

We consider the problem of estimating the slope parameter in circular functional linear regression, where scalar responses Y1,...,Yn are modeled in dependence of 1-periodic, second order stationary random functions X1,...,Xn. We consider an orthogonal series estimator of the slope function, by replacing the first m theoretical coefficients of its development in the trigonometric basis by adequate estimators. Wepropose a model selection procedure for m in a set of admissible values, by defining a contrast function minimized by our estimator and a theoretical penalty function; this first step assumes the degree of ill posedness to be known. Then we generalize the procedure to a random set of admissible m's and a random penalty function. The resulting estimator is completely data driven and reaches automatically what is known to be the optimal minimax rate of convergence, in term of a general weighted L2-risk. This means that we provide adaptive estimators of both the slope function and its derivatives

LPV Modeling of the Atmospheric Flight Dynamics of a Generic Parafoil Return Vehicle

Obtaining models that can be used for flight control is of outmost importance to ensure reliable guidance and navigation of spacecrafts, like a Generic Parafoil Return Vehicle (GPRV). In this paper, we convert an existing, high-fidelity nonlinear model of the atmospheric flight dynamics of a GPRV to a Linear Parameter-Varying (LPV) form that enables high-performance navigation control design. Application of existing systematic conversion methods for such complicated nonlinear models often result in complex LPV representations, which are not suitable for controller synthesis. We apply and compare state-of-the-art conversion techniques on the GPRV model, including learning based approaches, to optimize the complexity and conservatism of the resulting LPV embedding. The results show that we can obtain an LPV embedding that approximates the complex nonlinear dynamics sufficiently well, where the balance between complexity, conservatism and model performance is efficiently chosen

The quantum states for Hydrogen atom: spherical harmonics and the orbitals geometrical representation

Our work utilizes the quantum model of the hydrogen atom which is based on the Schrödinger equation with Coulomb potential. Specifically, we concentrate on the angular components of the wave eigenfunctions derived from this model. We consider the quantum states with n ≤ 4. In order to visualize the orbital shapes of these states, we built in the spherical coordinates system their 3D geometric representations. Furthermore, we use the corresponding spherical harmonics, to calculate the θ nodal values that describe the configurations of these orbital states

Swallowing Disorders after Oral Cavity and Pharyngolaryngeal Surgery and Role of Imaging

Head and neck squamous cell carcinoma is the sixth most common cancer diagnosed worldwide and the eighth most common cause of cancer death. Malignant tumors of the oral cavity, oropharynx, and larynx can be treated by surgical resection or radiotheraphy with or without chemotheraphy and have a profound impact on quality of life functions, including swallowing. When surgery is the chosen treatment modality, the patient may experience swallowing impairment in the oral and pharyngeal phases of deglutition. A videofluoroscopic study of swallow enables the morphodynamics of the pharyngeal-esophageal tract to be accurately examined in patients with prior surgery. These features allow an accurate tracking of the various phases of swallowing in real time, identifying the presence of functional disorders and of complications during the short- and long-term postoperative recovery. The role of imaging is fundamental for the therapist to plan rehabilitation. In this paper, the authors aim to describe the videofluoroscopic study of swallow protocol and related swallowing impairment findings in consideration of different types of surgery

Engineering Azobenzene Derivatives to Control the Photoisomerization Process

In this work, we show how the structural features of photoactive azobenzene derivatives can influence the photoexcited state behavior and the yield of the trans/cis photoisomerization process. By combining high-resolution transient absorption experiments in the vis-NIR region and quantum chemistry calculations (TDDFT and RASPT2), we address the origin of the transient signals of three poly-substituted push-pull azobenzenes with an increasing strength of the intramolecular interactions stabilizing the planar trans isomer (absence of intramolecular H-bonds, methyl, and traditional H-bond, respectively, for 4-diethyl-4′-nitroazobenzene, Disperse Blue 366, and Disperse Blue 165) and a commercial red dye showing keto-enol tautomerism involving the azo group (Sudan Red G). Our results indicate that the intramolecular H-bonds can act as a “molecular lock” stabilizing the trans isomer and increasing the energy barrier along the photoreactive CNNC torsion coordinate, thus preventing photoisomerization in the Disperse Blue dyes. In contrast, the involvement of the azo group in keto-enol tautomerism can be employed as a strategy to change the nature of the lower excited state and remove the nonproductive symmetric CNN/NNC bending pathway typical of the azo group, thus favoring the productive torsional motion. Taken together, our results can provide guidelines for the structural design of azobenzene-based photoswitches with a tunable excited state behavior