Exact Hairy Black Holes and their Modification to the Universal Law of Gravitation

In this paper two things are done. First, it is pointed out the existence of exact asymptotically flat, spherically symmetric black holes when a self interacting, minimally coupled scalar field is the source of the energy momentum of the Einstein equations in four dimensions. The scalar field potential is the recently found to be compatible with the hairy generalization of the Plebanski-Demianski solution of general relativity. This paper describes the spherically symmetric solutions that smoothly connect the Schwarzschild black hole with its hairy counterpart. The geometry and scalar field are everywhere regular except at the usual Schwarzschild like singularity inside the black hole. The scalar field energy momentum tensor satisfies the null energy condition in the static region of the spacetime. The first law holds when the parameters of the scalar field potential are fixed under thermodynamical variation. Secondly, it is shown that an extra, dimensionless parameter, present in the hairy solution, allows to modify the gravitational field of a spherically symmetric black hole in a remarkable way. When the dimensionless parameter is increased, the scalar field generates a flat gravitational potential, that however asymptotically matches the Schwarzschild gravitational field. Finally, it is shown that a positive cosmological constant can render the scalar field potential convex if the parameters are within a specific rank.Comment: Two new references, 10 pages, 2 figure

Zastosowanie programu gwarancji dla zdrowia jamy ustnej w opiece nad kobietą w ciąży w rodzinnym centrum zdrowia w Concepción, Chile, w latach 2014–2015

Indexación: Scopus.Background. Oral health plays a crucial role in general health, quality of life and well-being of pregnant women and their newborns. In Chile, pregnant women have dental care guaranteed by law. However, due to the lack of previous epidemiological studies on the benefits of this guarantee, it is necessary to describe this situation and evaluate the need to change the methods of providing dental services. Objectives. The objective of this study was to describe the pattern of providing dental benefits resulting from the Explicit Health Guarantee – Integral Oral Health in Pregnant Women (GES-SOIE) program to pregnant women attending the Juan Soto Fernández Family Health Center, Concepción, Chile, in 2014–2015. Material and methods. A cross-sectional study of the electronic dental records of patients admitted to GES-SOIE was conducted. The variables studied were sociodemographic data, dental chair hours, non-attendance, treatment completion, and the type of referral to secondary healthcare (SHC). Results. Of 233 pregnant women, 65.2% were registered for non-attendance, 21.2% required referral to SHC and 76.4% completed their treatment. When performing logistic regression, it was found that for each non-attendance the chance of not completing the treatment increased 1.4 times. Conclusions. The level of non-attendance and opting out of the treatment in pregnant women is high, which hinders the proper functioning and effectiveness of GES-SOIE. © 2018 by Wroclaw Medical University and Polish Dental Society.http://www.dmp.umed.wroc.pl/en/article/2018/55/2/179

Pattern formation in a predator-prey system characterized by a spatial scale of interaction

We describe pattern formation in ecological systems using a version of the classical Lotka-Volterra model characterized by a spatial scale which controls the predator-prey interaction range. Analytical and simulational results show that patterns can emerge in some regions of the parameters space where the instability is driven by the range of the interaction. The individual-based implementation captures realistic ecological features. In fact, spatial structures emerge in an erratic oscillatory regime which can contemplate predators' extinction.Comment: 5 pages, 4 figure

Limits to Sympathetic Evaporative Cooling of a Two-Component Fermi Gas

We find a limit cycle in a quasi-equilibrium model of evaporative cooling of a two-component fermion gas. The existence of such a limit cycle represents an obstruction to reaching the quantum ground state evaporatively. We show that evaporatively the \beta\mu ~ 1. We speculate that one may be able to cool an atomic fermi gas further by photoassociating dimers near the bottom of the fermi sea.Comment: Submitted to Phys. Rev

The effect of thermal annealing on the properties of Al-AlOx-Al single electron tunneling transistors

The effect of thermal annealing on the properties of Al-AlOx-Al single electron tunneling transistors is reported. After treatment of the devices by annealing processes in forming gas atmosphere at different temperatures and for different times, distinct and reproducible changes of their resistance and capacitance values were found. According to the temperature regime, we observed different behaviors as regards the resistance changes, namely the tendency to decrease the resistance by annealing at T = 200 degree C, but to increase the resistance by annealing at T = 400 degree C. We attribute this behavior to changes in the aluminum oxide barriers of the tunnel junctions. The good reproducibility of these effects with respect to the changes observed allows the proper annealing treatment to be used for post-process tuning of tunnel junction parameters. Also, the influence of the annealing treatment on the noise properties of the transistors at low frequency was investigated. In no case did the noise figures in the 1/f-regime show significant changes.Comment: 6 pages, 7 eps-figure

The Nuclear Stellar Cluster in the Seyfert~1 Galaxy NGC 3227: High Angular Resolution NIR Imaging and Spectroscopy

NIR high angular resolution speckle imaging and imaging spectroscopy of the nuclear region (10'' ~ 840pc) of the Seyfert1 galaxy NGC3227 are presented. A nuclear stellar cluster is slightly resolved in the J and H band with increasing contribution to the NIR continuum from the K to the J band. The stellar absorption lines are extended compared to the neighboring continuum suggesting a cluster size of ~ 70pc FWHM. Analysis of those lines suggests that the stars are contributing about 65% (40%) of the total continuum emission in the H (K) band in a 3.6'' aperture. Population synthesis in conjunction with NIR spectral synthesis indicates an age of 25 to 50 Myr when red supergiants contribute most to the NIR light. This is supported by published optical data on the MgIb line and the CaII triplet. Although a higher age of ~ 0.5 Gyr where AGB stars dominate the NIR light can not be excluded, the observed parameters are at the limit of those expected for a cluster dominated by AGB stars. However, in either case the resolved stellar cluster contributes only about ~ 15 % of the total dynamical mass in the inner 300pc implying another much older stellar population. Pure constant star formation over the last 10 Gyr can be excluded. Therefore, at least two star formation/starburst events took place in the nucleus of NGC3227. Since such sequences in the nuclear star formation history are also observed in the nuclei of other galaxies a link between the activity of the star formation and the AGN itself seems likely.Comment: accepted for publication in the Astrophysical Journal, 46 pages, 15 figure

AGN Black Hole Masses and Bolometric Luminosities

Black hole mass, along with mass accretion rate, is a fundamental property of active galactic nuclei. Black hole mass sets an approximate upper limit to AGN energetics via the Eddington limit. We collect and compare all AGN black hole mass estimates from the literature; these 177 masses are mostly based on the virial assumption for the broad emission lines, with the broad-line region size determined from either reverberation mapping or optical luminosity. We introduce 200 additional black hole mass estimates based on properties of the host galaxy bulges, using either the observed stellar velocity dispersion or using the fundamental plane relation to infer $\sigma$; these methods assume that AGN hosts are normal galaxies. We compare 36 cases for which black hole mass has been generated by different methods and find, for individual objects, a scatter as high as a couple of orders of magnitude. The less direct the method, the larger the discrepancy with other estimates, probably due to the large scatter in the underlying correlations assumed. Using published fluxes, we calculate bolometric luminosities for 234 AGNs and investigate the relation between black hole mass and luminosity. In contrast to other studies, we find no significant correlation of black hole mass with luminosity, other than those induced by circular reasoning in the estimation of black hole mass. The Eddington limit defines an approximate upper envelope to the distribution of luminosities, but the lower envelope depends entirely on the sample of AGN included. For any given black hole mass, there is a range in Eddington ratio of up to three orders of magnitude.Comment: 43 pages with 10 figures. Accepted for publication in Ap

NICS-TNG infrared spectroscopy of trans-neptunian objects 2000 EB173 and 2000 WR106

We report complete near-infrared (0.9-2.4 $\mu$m) spectral observations of trans-neptunian objects (TNOs) 2000 EB173 and 2000 WR106 collected using the new Near Infrared Camera Spectrometer (NICS) attached to the 3.56m Telescopio Nazionale Galileo (TNG). Both spectra are very red and with a quite strong and broad drop extending throughout the K band. However, while 2000 EB173 does not show any evidence of narrow absorption features, the spectrum of 2000 WR106 has quite deep water ice absorption at 1.5 and 2.0 $\mu$m. Moreover, the latter object is significantly less red than the former indicating, therefore, that the surface of 2000 WR106 is ``cleaner'' (i.e. less processed by particle irradiation) than that of 2000 EB173