Reframing landscape fragmentation's effects on ecosystem services.

REVIEWLandscape structure and fragmentation have important effects on ecosystem services, with a common assumption being that fragmentation reduces service provision. This is based on fragmentation's expected effects on ecosystem service supply, but ignores how fragmentation influences the flow of services to people. Here we develop a new conceptual framework that explicitly considers the links between landscape fragmentation, the supply of services, and the flow of services to people. We argue that fragmentation's effects on ecosystem service flow can be positive or negative, and use our framework to construct testable hypotheses about the effects of fragmentation on final ecosystem service provision. Empirical efforts to apply and test this framework are critical to improving landscape management for multiple ecosystem services.Australian Research Council Discovery ProjectAustralian Research Council's Centre of Excellence for Environmental DecisionsNERCChile Ministry of EducationCSIRO Integrative Natural Resource Management postgraduate fellowshipsCOLCIENCIA

Retinal blood vessels extraction using probabilistic modelling

© 2014 Kaba et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.The analysis of retinal blood vessels plays an important role in detecting and treating retinal diseases. In this review, we present an automated method to segment blood vessels of fundus retinal image. The proposed method could be used to support a non-intrusive diagnosis in modern ophthalmology for early detection of retinal diseases, treatment evaluation or clinical study. This study combines the bias correction and an adaptive histogram equalisation to enhance the appearance of the blood vessels. Then the blood vessels are extracted using probabilistic modelling that is optimised by the expectation maximisation algorithm. The method is evaluated on fundus retinal images of STARE and DRIVE datasets. The experimental results are compared with some recently published methods of retinal blood vessels segmentation. The experimental results show that our method achieved the best overall performance and it is comparable to the performance of human experts.The Department of Information Systems, Computing and Mathematics, Brunel University

On the dynamics of WKB wave functions whose phase are weak KAM solutions of H-J equation

In the framework of toroidal Pseudodifferential operators on the flat torus $\Bbb T^n := (\Bbb R / 2\pi \Bbb Z)^n$ we begin by proving the closure under composition for the class of Weyl operators $\mathrm{Op}^w_\hbar(b)$ with simbols $b \in S^m (\mathbb{T}^n \times \mathbb{R}^n)$. Subsequently, we consider $\mathrm{Op}^w_\hbar(H)$ when $H=\frac{1}{2} |\eta|^2 + V(x)$ where $V \in C^\infty (\Bbb T^n;\Bbb R)$ and we exhibit the toroidal version of the equation for the Wigner transform of the solution of the Schr\"odinger equation. Moreover, we prove the convergence (in a weak sense) of the Wigner transform of the solution of the Schr\"odinger equation to the solution of the Liouville equation on $\Bbb T^n \times \Bbb R^n$ written in the measure sense. These results are applied to the study of some WKB type wave functions in the Sobolev space $H^{1} (\mathbb{T}^n; \Bbb C)$ with phase functions in the class of Lipschitz continuous weak KAM solutions (of positive and negative type) of the Hamilton-Jacobi equation $\frac{1}{2} |P+ \nabla_x v_\pm (P,x)|^2 + V(x) = \bar{H}(P)$ for $P \in \ell \Bbb Z^n$ with $\ell >0$, and to the study of the backward and forward time propagation of the related Wigner measures supported on the graph of $P+ \nabla_x v_\pm$

Control interno y la rentabilidad de la empresa Albis Perú E.I.R.L. de Jaén - 2020

Objective: To determine the level of relationship between internal control and profitability of the company ALBIS PERU EIRL of Jaen, 2020. In the same way they resolved to handle a quantitative approach, with non- experimental design, cross-sectional, applied type, with causal correlational level, the technique used was the survey and the instrument was the questionnaire, which was applied to 45 workers in the area of logistics, accounting, decision making, warehouse and marketing of the company ALBIS PERU EIRL of Jaén, 2020. Obtaining a Spearman's Rho of 0.440, showing that internal control has a direct linear relationship with profitability, in the same way, the Sig. was less than 0.05, allowing to accept the research hypothesis. The most relevant conclusion was that as long as the control environment, control activities and supervision or monitoring are developed efficiently, the economic profitability of ALBIS PERU EIRL can be improved.Objetivo: Determinar el nivel de relación del control interno y la rentabilidad de la empresa ALBIS PERU EIRL de Jaén, 2020. De la misma manera resolvieron manejar un enfoque cuantitativo, con diseño no experimental, de corte transversal, de tipo aplicada, con nivel correlacional causal, la técnica manejada fue la encuesta y el instrumento fue el cuestionario, el cual, fue aplicado a 45 trabajadores del área de logística, contabilidad, toma de decisiones, almacén y comercialización de la empresa ALBIS PERU EIRL de Jaén, 2020. Obteniendo un Rho de Spearman del 0,440, evidenciando que el control interno posee una relación directa lineal con la rentabilidad, de la misma forma la Sig., fue menor del 0.05, permitiendo aceptar la hipótesis de investigación. La conclusión más relevante fue que mientras se desarrolle eficientemente el entorno de control, las actividades de control y la supervisión o monitoreo se podrá mejorar la rentabilidad económica de la empresa ALBIS PERU EIRL

Perfil de resistencia de Staphylococcus spp aislados de hemocultivos en el Hospital Central del Instituto de Previsión Social

Las infecciones nosocomiales por Staphylococcus spp constituyen uno de los problemas de mayor preocupación en salud pública en todo el mundo. Debido a que existen diferencias según centro hospitalario, paciente, área y tiempo de internación es esencial conocer el perfil de resistencia a los antibióticos más utilizados de las cepas de Staphylococcus involucradas en estas infecciones. El objetivo del presente estudio fue determinar el perfil de resistencia de los aislados de Staphylococcus aureus (Sau) y Estafilococo coagulasa negativo (ECN) de muestras de hemocultivos de pacientes adultos, pediátricos y recién nacidos internados entre el 1 de junio de 2005 al 30 de junio de2006, en varios servicios del Hospital Central del Instituto de Previsión Social (IPS.).Se realizó un análisis retrospectivo de los resultados de antibiograma realizados en el Servicio de Microbiología del IPS. Los antibióticos evaluados fueron oxacilina (OXA),penicilina (PEN), eritromicina (ERY), clindamicina (CLI), ciprofloxacina (CIP), gentamicina (GEN), trimetoprim-sulfametoxazol (TMS), tetraciclina (TET) y vancomicina (VAN). De 5698 hemocultivos realizados en este periodo, 1706 (30%) fueron positivos. De estos, en755 (44%) se aisló Staphylococcus spp; correspondiendo 327 (43,3%) a Sau y 428 (56,7%) a ECN. El perfil de resistencia para Sau y ECN fue respectivamente como sigue: OXA 64% y 87%, PEN 96% y 95%, ERY 48% y 52%, CIP 42% y 40%, GEN 48% y 48% yno presentaron R a VAN. El 58% de los Sau y el 56% de los ECN fueron resistentes a más de 4 antibióticos. La alta frecuencia de resistencia a la meticilina y la poliresistencia hallada en este trabajo deben ser tenidos en cuenta a la hora de indicar esquemas deantibióticos empíricos y para realizar ajustes oportunos de los ya iniciados. No se encontró ninguna cepa resistente a la vancomicina, que es considerada el mejor antimicrobiano disponible para el tratamiento de infecciones por estafilococos resistentesa las penicilinas que no son inhibidas por las penicilinasas

Thermodynamics and Instabilities of a Strongly Coupled Anisotropic Plasma

We extend our analysis of a IIB supergravity solution dual to a spatially anisotropic finite-temperature N=4 super Yang-Mills plasma. The solution is static, possesses an anisotropic horizon, and is completely regular. The full geometry can be viewed as a renormalization group flow from an AdS geometry in the ultraviolet to a Lifshitz-like geometry in the infrared. The anisotropy can be equivalently understood as resulting from a position-dependent theta-term or from a non-zero number density of dissolved D7-branes. The holographic stress tensor is conserved and anisotropic. The presence of a conformal anomaly plays an important role in the thermodynamics. The phase diagram exhibits homogeneous and inhomogeneous (i.e. mixed) phases. In some regions the homogeneous phase displays instabilities reminiscent of those of weakly coupled plasmas. We comment on similarities with QCD at finite baryon density and with the phenomenon of cavitation.Comment: 62 pages, 13 figures; v2: typos fixed, added reference

Ram pressure feeding super-massive black holes

When supermassive black holes at the center of galaxies accrete matter (usually gas), they give rise to highly energetic phenomena named Active Galactic Nuclei (AGN). A number of physical processes have been proposed to account for the funneling of gas towards the galaxy centers to feed the AGN. There are also several physical processes that can strip gas from a galaxy, and one of them is ram pressure stripping in galaxy clusters due to the hot and dense gas filling the space between galaxies. We report the discovery of a strong connection between severe ram pressure stripping and the presence of AGN activity. Searching in galaxy clusters at low redshift, we have selected the most extreme examples of jellyfish galaxies, which are galaxies with long tentacles of material extending for dozens of kpc beyond the galaxy disk. Using the MUSE spectrograph on the ESO Very Large Telescope, we find that 6 out of the 7 galaxies of this sample host a central AGN, and two of them also have galactic-scale AGN ionization cones. The high incidence of AGN among the most striking jellyfishes may be due to ram pressure causing gas to flow towards the center and triggering the AGN activity, or to an enhancement of the stripping caused by AGN energy injection, or both. Our analysis of the galaxy position and velocity relative to the cluster strongly supports the first hypothesis, and puts forward ram pressure as another, yet unforeseen, possible mechanism for feeding the central supermassive black hole with gas.Comment: published in Nature, Vol.548, Number 7667, pag.30