Modified spinning black holes

In the context of f(R) modified gravity theories we determine that the black holes existence is determined by the sign of a parameter dependent of the mass, the charge, the spin and the scalar curvature. We obtain the different astrophysical objects derived from the presence of different horizons. Thermodynamics for this kind of black holes is studied for negative values of the curvature, revealing that we can distinguish between two kinds of BH: fast and slow.Comment: 4 pages, 6 figures, Contribution to the ERE2011 Spanish Relativity Meeting, Madrid 201

Opposite polarity field with convective downflow and its relation to magnetic spines in a sunspot penumbra

We discuss NICOLE inversions of Fe I 630.15 nm and 630.25 nm Stokes spectra from a sunspot penumbra recorded with the CRISP imaging spectropolarimeter on the Swedish 1-m Solar Telescope at a spatial resolution close to 0.15". We report on narrow radially extended lanes of opposite polarity field, located at the boundaries between areas of relatively horizontal magnetic field (the intra-spines) and much more vertical field (the spines). These lanes harbor convective downflows of about 1 km/s. The locations of these downflows close to the spines agree with predictions from the convective gap model (the "gappy penumbra") proposed six years ago, and more recent 3D MHD simulations. We also confirm the existence of strong convective flows throughout the entire penumbra, showing the expected correlation between temperature and vertical velocity, and having vertical RMS velocities of about 1.2 km/s.Comment: Accepted for publication in A&A (06-March-2013). Minor corrections made in this version

Ion condensation on charged patterned surfaces

We study ion condensation onto a patterned surface of alternating charges. The competition between self-energy and ion-surface interactions leads to the formation of ionic crystalline structures at low temperatures. We consider different arrangements of underlying ionic crystals, including single ion adsorption, as well as the formation of dipoles at the interface between charged domains. Molecular dynamic simulation illustrates existence of single and mixed phases. Our results contribute to understanding pattern recognition, and molecular separation and synthesis near patterned surfaces.Comment: 3 figure

Spin-Phonon Coupling in Iron Pnictide Superconductors

The magnetic moment in the parent phase of the iron-pnictide superconductors varies with composition even when the nominal charge of iron is unchanged. We propose the spin-lattice coupling due to the magneto-volume effect as the primary origin of this effect, and formulate a Landau theory to describe the dependence of the moment to the Fe-As layer separation. We then compare the superconductive critical temperature of doped iron pnictides to the local moment predicted by the theory, and suggest that the spin-phonon coupling may play a role in the superconductivity of this compound

Knowledge, Attitudes, and Practices on Solid Waste Management among Undergraduate Students in a Philippine State University

This cross-sectional survey was conducted to capture the knowledge, attitude, and practices (KAPs) on solid waste management (SWM) from a total of 2,528 undergraduate students enrolled in the Laguna State Polytechnic University – Los Baños Campus (LSPU-LBC) during the 2nd Semester, A.Y. 2015-16. While most students had satisfactory levels for knowledge (73.4%) and attitude (71.0%) on SWM-related matters, less than half (43.1%), showed satisfactory practice level. Similarly, the relatively higher average rating for knowledge (87.8%) and attitude (87.0%) of the students were both inconsistent with the lower average practice rating (72.5%). The average KAP rating was 82.3%, with merely half (55%) had satisfactory KAP ratings. The interaction effect between knowledge and attitude ratings significantly predicted the students’ practice rating (r2=0.11; P<0.005). The students’ average KAP ratings were also somehow also linked to their social status, whereby, satisfactory KAP rating was significantly associated with students from medium-sized families (5-9 members), having parents with moderate academic backgrounds and held permanent jobs. The students’ perceived abundance-ranking for some common household solid wastes, as well as household solid waste-stocking preference and disposal systems are also presented. Inclusion of relevant topics–with emphasis on proper SWM and other solid waste-issues–in the undergraduate curriculum of LSPU-LBC is recommended to promote awareness on environmental issues and improve attitude of college students towards environmentally-sustainable practices. Keywords: Environment, KAP, Philippines, Solid waste management, Student