Electron-impact electronic excitation of molecular nitrogen using the Schwinger multichannel variational method

The Schwinger multichannel method is applied to study the low-energy electron-impact excitation of molecular nitrogen. The scattering amplitudes are obtained within the minimal orbital basis for single configuration interactions (MOBSCI) level of approximation, for impact energies from near threshold up to 30 eV. Through the use of the MOBSCI strategy we have performed a close-coupling calculation for up to nine states, including the ground state and all singlet and triplet states resulting from the pi(u)->pi(g) transitions. Integral and differential cross sections for the X (1)Sigma(+)(g)-> A (3)Sigma(+)(u), W (3)Delta(u), B-' (3)Sigma(-)(u), a(') (1)Sigma(-)(u), and w (1)Delta(u) electronic transitions are presented and compared with available experimental data and also with other theoretical results.75

Polarization effects on electronic excitation of molecules by low-energy electron impact: Study on e(-)-furan scattering

The Schwinger multichannel method is applied to study the influence of polarization effects on the electronic excitation of the furan molecule by low-energy electron impact. We discuss the importance of inclusion of these effects through the comparison of theoretical results for the electronic excitation of the (3)B(2) state of furan obtained with and without the proper treatment of the polarization of the target. The electron-furan scattering presents two prominent shape resonances in the (2)A(2) and (2)B(1) symmetries at around the electronic excitation threshold of the (3)B(2) state (3.7 eV). At this low-energy, the inclusion of polarization effects in the calculation moves to lower energies the resonances positions obtained either in the close-coupling or in the static-exchange level of approximation. This phenomenon strongly influences the electronic excitation process. The present results show that a simple close-coupling calculation cannot be applied for molecular systems with low-energy electronic excitation thresholds around misplaced resonances.77

A comparative study of elastic scattering of low-energy electrons by boron, aluminum and gallium trihalides

In this paper we present integral, differential and momentum transfer cross sections for elastic scattering of low-energy electrons by some metal-halogen molecular compounds, namely, BF3, BCl3, BBr3, BI3, AlF3, AlCl3, AlBr3, AlI3, GaF3, GaCl3, GaBr3, and GaI3. The pseudopotential based calculations were carried out with the Schwinger multichannel method at the static-exchange level of approximation. It is the purpose of this work to make a comparative study of the scattering processes involving aluminum and gallium trihalides with previous results for the boron ones [M. H. F. Bettega, Phys. Rev. A 61, 042703 (2000)]. We find through direct comparison of the elastic cross sections that, at low energies, the scattering processes are mainly dominated by the halogen atoms. (C) 2003 American Institute of Physics.1181758

Low-energy electron collisions with acetic acid

We present cross sections for elastic collisions of low-energy electrons with acetic acid. We employed the Schwinger multichannel method with pseudopotentials in the static-exchange and static-exchange plus polarization approximations, for energies ranging from 0.1 to 10 eV. We found a pi(*) shape resonance around 1.7 eV, corresponding to the A(') symmetry of the C(s) group. This resonant state was assigned to the experimental dissociative electron attachment peak at 1.7 eV yielding CH(3)COO(-)+H. We also performed a series of electronic structure calculations using a small basis set for acetic, formic, and trifluoroacetic acids, which exhibit a similar behavior with respect to the dissociative electron attachment. We believe that hydrogen elimination triggered off by electron capture into a pi(*) resonance could be a general property of carboxylic acids.79

Body adiposity index to analyze the percentage of fat in young men aged between 7 and 17 years

BACKGROUND: The body adiposity index (BAI), uses anthropometry to estimate percent body fat (%F). However, previous studies have shown that the BAI has limited accuracy for children and adolescents. OBJECTIVE: We propose to develop and validate an adjusted BAI for use in male children and adolescents from 7 to 17 years of age. METHODS: The sample consisted of 141 physically active male children and adolescents (age: 12.5 ± 2.14). The %F was determined by X-ray dual energy absorptometry equipment (DXA) as the standard method and by BAI, using an equation that uses height and hip circumference. Arithmetic modeling was used to adjust the structure of the BAI mathematical model. RESULTS: The BAI arithmetic adjustment was successful, resulting in the mathematical model named in the present study of adjusted body adiposity index (BAIADJ ). BAI and BAIADJ correlated with DXA (r ≤ .70, p  .05). CONCLUSION: The adjusted model of the body adiposity index proves to be an effective tool for the analysis of the fat percentage in young males. In addition, it demonstrated significant degrees of agreement and validity in relation to DXA

Ultrastructure of the Intramandibular Gland of Workers and Queens of the Stingless Bee, Melipona quadrifasciata

The intramandibular glands of workers and queens of Melipona quadrifasciata Lepeletier (Hymenoptera: Apidae), at different ages and from different functional groups, were studied using light and transmission electron microscopy. The results demonstrated that these glands are composed of two types of secretory structures: 1.A hypertrophied epidermis on the dorsal side of the mandible that is an epithelial gland. 2. Free secretory cells filling the inner spaces of the appendices that constitute a unicellular gland. The epithelial gland is larger in the young (1-2-day-old workers), and the gland becomes involuted during the nurse worker stage. The unicellular glands of the workers posses some secretion during all of the studied phases, but secretory activity is more intensive in the foraging workers. Vesicles of secretion are absent in the unicellular glands of queens. These results demonstrate that these glands show functional adaptations in different castes corresponding to the functions of each caste

Trend analysis of the quality indicators for the Brazilian cervical cancer screening programme by region and state from 2006 to 2013

Quality indicators for the Brazilian cervical cancer screening programme can provide a perspective on its effectiveness in Brazilian macro-regions and states. The aim of this study was to perform a trend analysis of the cervical cancer screening program's quality indicators, according to Brazilian regions and states, from 2006 to 2013.(undefined)info:eu-repo/semantics/publishedVersio