Developmental and functional effects of steroid hormones on the neuroendocrine axis and spinal cord

This review highlights the principal effects of steroid hormones at central and peripheral levels in the neuroendocrine axis. The data discussed highlight the principal role of oestrogens and testosterone in hormonal programming in relation to sexual orientation, reproductive and metabolic programming, and the neuroendocrine mechanism involved in the development of polycystic ovary syndrome phenotype. Moreover, consistent with the wide range of processes in which steroid hormones take part, we discuss the protective effects of progesterone on neurodegenerative disease and the signalling mechanism involved in the genesis of oestrogen-induced pituitary prolactinomas.Fil: Zubeldia Brenner, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Roselli, C. E.. Oregon Health and Science University Portland; Estados UnidosFil: Recabarren, S. E.. Universidad de Concepción; ChileFil: Gonzalez Deniselle, Maria Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lara, H. E.. Universidad de Chile; Chil

A Contracting, Turbulent, Starless Core in the Serpens Cluster

We present combined single-dish and interferometric CS(2--1) and N2H+(1--0) observations of a compact core in the NW region of the Serpens molecular cloud. The core is starless according to observations from optical to millimeter wavelengths and its lines have turbulent widths and ``infall asymmetry''. Line profile modeling indicates supersonic inward motions v_in>0.34 km/s over an extended region L>12000AU. The high infall speed and large extent exceeds the predictions of most thermal ambipolar diffusion models and points to a more dynamical process for core formation. A short (dynamic) timescale, ~1e5 yr=L/v_in, is also suggested by the low N2H+ abundance ~1e-10.Comment: 11 pages including 2 figures. Accepted for publication in the Astrophysical Journal Letter

The role of stellar radial motions in shaping galaxy surface brightness profiles

Aims. The physics driving features such as breaks observed in galaxy surface brightness (SB) profiles remains contentious. Here, we assess the importance of stellar radial motions in shaping their characteristics. Methods. We use the simulated Milky Way-mass cosmological discs from the Ramses Disc Environment Study (RaDES) to characterise the radial redistribution of stars in galaxies displaying type-I (pure exponentials), II (downbending), and III (upbending) SB profiles. We compare radial profiles of the mass fractions and the velocity dispersions of different sub-populations of stars according to their birth and current location. Results. Radial redistribution of stars is important in all galaxies regardless of their light profiles. Type-II breaks seem to be a consequence of the combined effects of outward-moving and accreted stars. The former produce shallower inner profiles (lack of stars in the inner disc) and accumulate material around the break radius and beyond, strengthening the break; the latter can weaken or even convert the break into a pure exponential. Further accretion from satellites can concentrate material in the outermost parts, leading to type-III breaks that can coexist with type-II breaks, but situated further out. Type-III galaxies would be the result of an important radial redistribution of material throughout the entire disc, as well as a concentration of accreted material in the outskirts. In addition, type-III galaxies display the most efficient radial redistribution and the largest number of accreted stars, followed by type-I and II systems, suggesting that type-I galaxies may be an intermediate case between types-II and III. In general, the velocity dispersion profiles of all galaxies tend to flatten or even increase around the locations where the breaks are found. The age and metallicity profiles are also affected, exhibiting different inner gradients depending on their SB profile, being steeper in the case of type-II systems (as found observationally). The steep type-II profiles might be inherent to their formation rather than acquired via radial redistribution

Arene C-H Amination at Nickel in Terphenyl–Diphosphine Complexes with Labile Metal–Arene Interactions

The meta-terphenyl diphosphine, m-P_2, 1, was utilized to support Ni centers in the oxidation states 0, I, and II. A series of complexes bearing different substituents or ligands at Ni was prepared to investigate the dependence of metal–arene interactions on oxidation state and substitution at the metal center. Complex (m-P_2)Ni (2) shows strong Ni^0–arene interactions involving the central arene ring of the terphenyl ligand both in solution and the solid state. These interactions are significantly less pronounced in Ni^0 complexes bearing L-type ligands (2-L: L=CH_3CN, CO, Ph_2CN_2), Ni^IX complexes (3-X: X=Cl, BF_4, N_3, N_3B(C_6F_5)_3), and [(m-P_2)Ni^(II)Cl_2] (4). Complex 2 reacts with substrates, such as diphenyldiazoalkane, sulfur ylides (Ph_2=CH_2), organoazides (RN_3: R=para-C_6H_4OMe, para-C_6H_4CF_3, 1-adamantyl), and N_2O with the locus of observed reactivity dependent on the nature of the substrate. These reactions led to isolation of an η^1-diphenyldiazoalkane adduct (2-Ph_2CN_2), methylidene insertion into a Ni-P bond followed by rearrangement of a nickel-bound phosphorus ylide (5) to a benzylphosphine (6), Staudinger oxidation of the phosphine arms, and metal-mediated nitrene insertion into an arene C-H bond of 1, all derived from the same compound (2). Hydrogen-atom abstraction from a Ni^I–amide (9) and the resulting nitrene transfer supports the viability of Ni–imide intermediates in the reaction of 1 with 1-azido-arenes

Two-state behaviour of Kondo trimers

The electronic properties and spectroscopic features of a magnetic trimer with a Kondo-like coupling to a non-magnetic metallic substrate are analyzed at zero temperature. The substrate density of states is depressed in the trimer neighbourhood, being exactly zero at the substrate chemical potential. The size of the resonance strongly depends on the magnetic state of the trimer, and exhibits a two-state behavior. The geometrical dependence of these results agree qualitatively with recent experiments and could be reproduced in a triangular quantum dot arrangement.Comment: 5 pages, including 4 figure

Campo tensional en el entorno de una fisura. Determinación de KI y KII usando técnicas fotoelásticas

Trabajo reproducido y difundido en el repositorio idUS con permiso de la Asociación Española de Ingeniería Mecánica (AEIM)Tras introducir la forma general del campo de tensiones en un borde de grieta se hace una exposición detallada de los métodos para medir K I y K II, resaltando sus ventajas e inconvenientes. Por su generalldad, se ha implementado un método que desarrolla en serie las funciones de tensión. La introducción de las medidas fotoelásticas (que pueden ser de campo lejano) conduce a un sistema sobredetermlnado no lineal de ecuaclones, que es resuelto por un métooo de Neewton-Raphson y mínimos cuadrados. Sobre una aplicación experimental se comentan las caracterlstlcas de este métodoFirst of all, the general form of the crack-tip stress field is introduced. Then, a detailed review of K I-K II methods is pressented, showing thelr features. A stress-functions series expansion method has been implemented, due to its generality. Experimental far-fleld isochromatic polnts are used to fit the series expanslon coefflclents and the overdeterminlstlc non-linear equation system is solved with a Newton-Rapshon least-squares method. Finally the features of thls method are dlscussed uslng an experimental applicatio

Facilitating respite, communication, and care for children with intellectual and developmental disabilities: Preliminary evaluation of the Caregiver Pain Information Guide.

Background: Pain is common in children with intellectual and developmental disabilities (I/DD) and yet is an understudied issue. Respite workers commonly care for children with I/DD but are lacking in resources to assist in pain assessment and management for this population. Without adequate knowledge in this domain, children with I/DD are at risk of their pain being underrecognized and undermanaged. A resource for caregivers was developed to address this issue, facilitating communication between parents and respite workers and better addressing the complex pain-related needs of children with I/DD. The objective of this study was to solicit initial feedback on the content, feasibility, and usability of the resource. Method/Procedure: Semistructured individual interviews and questionnaires were completed with 7 parents of children with I/DD and 6 respite workers. Results: All participants viewed the resource as important and potentially useful. Content analyses indicated that participants appreciated the comprehensiveness and format of the resource, whereas the modifiability was identified as an area for improvement. Participants believed that the resource would be useful across settings with a variety of caregivers. Three categories of considerations were identified as potential facilitators and barriers for implementation: consideration of how the resource is being completed, who is completing it, and organization-based procedures. Discussion/Conclusions: Results from this study suggest that the Caregiver Pain Information Guide is a promising resource for helping respite workers better understand pain in children with I/DD. Future work is needed on implementation and impact of this resource in community settings. (PsycInfo Database Record (c) 2020 APA, all rights reserved)Implications for Impact Statement—Children with intellectual and developmental disabilities experience pain frequently and are at risk of having their pain missed by caregivers. Parents would like to share pain-related knowledge and skills specific to their children with intellectual and developmental disabilities with those who support their child in other settings. The Caregiver Pain Information Guide was created to facilitate communication between parents and caregivers of these children. The current article discusses initial feedback from parents and respite workers regarding this new tool. (PsycInfo Database Record (c) 2020 APA, all rights reserved