Study of elastic deformations in tapered nanowires

In this work, the calculation of the values of elastic deformations and stresses arising in tapered nanowires is carried out. It was found that in tapered nanowires the magnitude of deformations changes from the base of the nanowire to its tip not linearly (as would be the case in cylindrical nanowires), but in a more complex manner. The ranges of conicity angles at which an extended region of increased stresses can appear in tapered nanowires have been determined.

Tangential high-density electrode insertions allow to simultaneously measure neuronal activity across an extended region of the visual field in mouse superior colliculus

The superior colliculus (SC) is a midbrain structure that plays a central role in visual processing. Although we have learned a considerable amount about the function of single SC neurons, the way in which sensory information is represented and processed on the population level in awake behaving animals and across a large region of the retinotopic map is still largely unknown. Partially because the SC is anatomically located below the cortical sheet and the transverse sinus, it is technically difficult to measure neuronal activity from a large population of neurons in SC. To address this, we propose a tangential recording configuration using high-density electrode probes (Neuropixels) in mouse SC in vivo that permits a large number of recording sites (~200) accessibility inside the SC circuitry. This approach thereby provides a unique opportunity to measure the activity of SC neuronal populations composing up to ~2 mm of SC tissue and characterized by receptive fields covering an extended region in the visual field. Here we describe how to perform tangential recordings along the anterior-posterior and the medio-lateral axis of the mouse SC in vivo and how to combine this approach with optogenetic tools for cell-type identification on the population level.

Chemical modeling of the complex organic molecules in the extended region around Sagittarius B2

Context. The chemical differentiation of seven complex organic molecules (COMs) in the extended region around Sagittarius B2 (Sgr B2) has been previously observed: CH2OHCHO, CH3OCHO, t-HCOOH, C2H5OH, and CH3NH2 were detected both in the extended region and near the hot cores Sgr B2(N) and Sgr B2(M), while CH3OCH3 and C2H5CN were only detected near the hot cores. The density and temperature in the extended region are relatively low in comparison with Sgr B2(N) and Sgr B2(M). Different desorption mechanisms, including photodesorption, reactive desorption, and shock heating, and a few other mechanisms have been proposed to explain the observed COMs in the cold regions. However, they fail to explain the deficiency of CH3OCH3 and C2H5CN in the extended region around Sgr B2. Aims. Based on known physical properties of the extended region around Sgr B2, we explored under what physical conditions the chemical simulations can fit the observations and explain the different spatial distribution of these seven species in the extended region around Sgr B2. Methods. We used the macroscopic Monte Carlo method to perform a detailed parameter space study. A static physical model and an evolving physical model including a cold phase and a warm-up phase were used, respectively. The fiducial models adopt the observed physical parameters except for the local cosmic ray ionization rate ζCR. In addition to photodesorption that is included in all models, we investigated how chain reaction mechanism, shocks, an X-ray burst, enhanced reactive desorption and low diffusion barriers could affect the results of chemical modeling. Results. All gas-grain chemical models based on static physics cannot fit the observations, except for the high abundances of CH3NH2 and C2H5CN in some cases. The simulations based on evolving physical conditions can fit six COMs when T ~ 30−60 K in the warm-up phase, but the best-fit temperature is still higher than the observed dust temperature of 20 K. The best agreement between the simulations and all seven observed COMs at a lower temperature T ~ 27 K is achieved by considering a short-duration ≈102 yr X-ray burst with ζCR = 1.3 × 10−13 s−1 at the early stage of the warm-up phase when it still has a temperature of 20 K. The reactive desorption is the key mechanism for producing these COMs and inducing the low abundances of CH3OCH3 and C2H5CN. Conclusions. We conclude that the evolution of the extended region around Sgr B2 may have begun with a cold, T ≤ 10 K phase followed by a warm-up phase. When its temperature reached about T ~ 20 K, an X-ray flare from the Galactic black hole Sgr A* with a short duration of no more than 100 yr was acquired, affecting strongly the Sgr B2 chemistry. The observed COMs in Sgr B2 are able to retain their observed abundances only several hundred years after such a flare, which could imply that such short-term X-rays flares occur relatively often, likely associated with the accretion activity of the Sgr A* source.

THE HH34 JET/COUNTERJET SYSTEM AT 1.5 AND 4.5μm

We present a (previously unpublished) 1.5µm archival HST image of the HH 34 Herbig-Haro jet, in which the northern counterjet is seen at an unprecedented angular resolution of ≈ 0.1′′ (this counterjet had only been imaged previously at lower resolution with Spitzer). The jet/counterjet structure observed in this image shows evidence of low-amplitude, point-symmetric deviations from the outflow axis, indicating the presence of a precession in the ejection direction. We use the ratios between the 1.5 and 4.5 µm intensities of the emitting knots (from the HST image and from a previously published 4.5 µm Spitzer image) to obtain an estimate of the spatial dependence of the optical extinction to the HH 34 jet/counterjet system. We find evidence for extinction from a central, dense core surrounding the outflow source and from a more extended region in the foreground of the HH 34 counterjet.

Permanent education in the vaccination room: what is the reality?

ABSTRACT Objective: To understand, from the perspective of the professional, the Permanent Education (PE) in the vaccination room in its real context. Method: Multiple holistic-qualitative case studies, based on Maffesoli’s Interpretive Sociology with 56 participants from four microregions of the Western Extended Region of Minas Gerais State. Results: They present PE as infrequent and insufficient. They denote that the practical-theoretical experience with vaccine contributes to the work; the search for knowledge, starting from the professional itself; and the professional training fails to perform in the vaccination room. Final considerations: The notions of PE are linked to the daily needs of individuals and services, with indication of being interactive, periodic, in specific and non-global issues for better assimilation. Obstacles to the non-implementation of PEH are realized by the workload associated with insufficient human resources, the distance of the nurses from the vaccination room and the lack of support from the higher levels.

The GEF model: Assessment of fission-fragment properties over an extended region

Calculations with the fission model GEF are performed over an extended region in fissioning-system mass A, charge Z, excitation energy E∗ and angular momentum L. The present contribution focuses on fission-fragment mass and isotopic distributions, benefiting from recent innovative measurements. The influence of the system (A, Z, E∗, L) properties and of multi-chance fission is studied. The impact of accurate experimental knowledge about these properties and instrumental resolution is discussed. The need of as selective and accurate as possible experimental data to improve the model is demonstrated.