Black holes in Einstein-Gau\ss -Bonnet-dilaton theory

Generalizations of the Schwarzschild and Kerr black holes are discussed in an astrophysically viable generalized theory of gravity, which includes higher curvature corrections in the form of the Gauss-Bonnet term, coupled to a dilaton. The angular momentum of these black holes can slightly exceed the Kerr bound. The location and the orbital frequency of particles in their innermost stable circular orbits can deviate significantly from the respective Kerr values. Study of the quasinormal modes of the static black holes gives strong evidence that they are mode stable against polar and axial perturbations. Future gravitational wave observations should improve the current bound on the Gauss-Bonnet coupling constant, based on observations of the low-mass x-ray binary A 0620-00.Comment: 8 pages, 7 figure

The reaction mechanism of metallo-beta-lactamases is tuned by the conformation of an active site mobile loop

Carbapenems are "last resort" β-lactam antibiotics used to treat serious and life-threatening health care-associated infections caused by multidrug-resistant Gram-negative bacteria. Unfortunately, the worldwide spread of genes coding for carbapenemases among these bacteria is threatening these life-saving drugs. Metallo-β-lactamases (MβLs) are the largest family of carbapenemases. These are Zn(II)-dependent hydrolases that are active against almost all β-lactam antibiotics. Their catalytic mechanism and the features driving substrate specificity have been matter of intense debate. The active sites of MβLs are flanked by two loops, one of which, loop L3, was shown to adopt different conformations upon substrate or inhibitor binding, and thus are expected to play a role in substrate recognition. However, the sequence heterogeneity observed in this loop in different MβLs has limited the generalizations about its role. Here, we report the engineering of different loops within the scaffold of the clinically relevant carbapenemase NDM-1. We found that the loop sequence dictates its conformation in the unbound form of the enzyme, eliciting different degrees of active-site exposure. However, these structural changes have a minor impact on the substrate profile. Instead, we report that the loop conformation determines the protonation rate of key reaction intermediates accumulated during the hydrolysis of different β-lactams in all MβLs. This study demonstrates the existence of a direct link between the conformation of this loop and the mechanistic features of the enzyme, bringing to light an unexplored function of active-site loops on MβLs.Fil: Palacios, Antonela Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Mojica, María F.. Case Western Reserve University; Estados UnidosFil: Giannini, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Taracila, Magdalena A.. Case Western Reserve University; Estados Unidos. Louis Stokes Veterans Affairs Medical Center; Estados UnidosFil: Bethel, Christopher R.. Louis Stokes Veterans Affairs Medical Center; Estados UnidosFil: Alzari, Pedro M.. Institut Pasteur de Paris; FranciaFil: Otero, Lisandro Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Klinke, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Llarrull, Leticia Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Bonomo, Robert A.. Case Western Reserve University; Estados UnidosFil: Vila, Alejandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentin

A Dynamic Optimization Framework with Model Predictive Control Elements for Long Term Planning of Capacity Investments in a District Energy System

The capacity expansion of a district heating system is studied with the objective of evaluating the investment decision timing and type of capacity expansion. District energy is an energy generation system that provides energy, such as heat and electricity, generated at central locations and distributed to the surrounding area. The study develops an optimization framework to find the optimal investment schedule over a 30 year horizon with the options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that can provide heat and electricity. In district energy systems, the investment decision on the capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. The main contribution of this work is to formulate the capacity planning over a time horizon asa dynamic optimal control problem. In this way, an initial system configuration can be modified by a \u27controller\u27 that optimally applies control actions that drive the system from an initial state to an optimal state. The optimal control is a model predictive control (MPC) formulation that not only provides the timing and size of the capacity investment, but also guidance on the mode of operation that meets optimal economic objectives with the given capacity

Síndrome compartimental por extravasación de líquidos en paciente pediátrico, reporte de un caso y revisión de la literatura.: Compartment syndrome due to liquid extravasation in a pediatric patient. Case report and bibliographic review

Extravasation Compartment Syndrome (SCE) is an infrequent pathology, with an incidence of 0,01-6,5%, whom 1,8-11% are children. Communication in children is usually difficult, with high risk of development of SCE. A case about a 9 month old male patient with an over-infected viral pneumonia and a triggered SCE is presented. He received compartmental decompression of right forearm and right hand; however he presented mild sequelae. Treatment of extravasation injury is not always sufficient enough. Mild-to-moderate complications or SCE can be presented. Recognizing clinical manifestations and risk factors and the use of auxiliary studies is fundamental for a good diagnosis and as prevention in children. Faciotomies, gold standard for treatment, are not completely safe, and have an impact on morbidity. Early protocols against extravasation, early examination by surgeon and investigation about SCE in chil-dren are recommended.El Síndrome Compartimental por Extravasación (SCE) es una patología poco frecuente, con una incidencia de 0,01-6,5%, 1.8-11% en niños. En niños pequeños la comunicación es difícil y aumenta el riego de desarrollo de SCE. Se presenta un caso de un masculino de 9 meses de edad, con Neumonía viral sobreinfectada que desencadena SCE; recibió descompresión compartimental del antebrazo y mano derecha; con desarrollo de secuelas leves. Aplicar tratamiento para lesión por extravasación no siempre es suficiente; existen complicaciones leves-moderadas o SCE. Reconocer manifestaciones clínicas y factores de riesgo es fundamental para el diagnóstico, con estudios auxiliares como precaución en niños. La faciotomía, tratamiento estándar de oro; no es inocua e impacta en la morbilidad. Se recomiendan protocolos oportunos para extravasación, valoración temprana por cirujano, investigaciones en pediatría

Utilization of Plant Refuses as Component of Heavy Metal Ion Sensors in Water Samples

Waste materials like fruit and vegetable refuses were utilized as component of sensors capable of detecting heavy metals like lead ions and mercury ions by electrochemical method. The ability of the fabricated sensors to detect the presence of heavy metals was analyzed using electrochemical methods like cyclic voltammetry and differential pulse anodic stripping voltammetry. Results showed that the fabricated electrode were able to detect the presence of mercury and lead ions in aqueous solutions

Análisis de la educación ambiental en bogota en la zona 16 puente aranda

La contaminación ambiental en nuestras áreas urbanas y rurales constituyen una problemática de interés social el día de hoy, pues el responsable del deterioro de los habitas, entendido este como el entorno en el que la población desarrolla la totalidad de sus actividades, la vivienda adecuada y la disponibilidad de sus servicios públicos en la vivienda constituyen componentes fundamentales para el ejercicio del derecho a un hábitat seguro y saludable. Además de las condiciones ambientales de la ciudad de Bogotá y del país, es el ser humano quien es responsable de sus acciones en los perímetros tanto urbanos como rurales. Por ello es importante que las entidades educativas, en todos sus diferentes grados intensifiquen y/o fortalezcan su curriculum o pensum del área de Educación Ambiental, o que el modelo pedagógico actual sea revisado y se estructure con procesos de enseñanza decisivos, enmarcados hacia el medio ambiente, con el compromiso de todos individuos esta educación debe estar orientada al desarrollo sostenible y buscando un mejoramiento en la calidad de vida de los ciudadanos. Lo anterior con el fin de transmitir una serie de valores y hábitos que conlleven a las futuras generaciones al respeto por nuestros recursos naturales y el ambiente. Dicha educación ambiental debe ser replicada a nuestros familiares y conciudadanos, por todos y cada uno de los alumnos de las diferentes instituciones educativas, con una verdadera conciencia ambiental irradie el amor y respeto por nuestros recursos naturales y el ambiente. Lo anterior en corresponsabilidad como ciudadanos con las instituciones estatales, encargadas también de la educación ambiental y el control de medio ambiente en el Distrito Capital área urbana y rural.Environmental pollution in our urban and rural areas becomes a problem of social interest today, since it is responsible for the habitat’s deterioration, understood as the environment in which the population develops all of its activities, adequate housing and the availability of its public services constitute fundamental components for the exercise of the right to a safe and healthy habitat. In addition to the environmental conditions of Bogotá city and the country, it is the human being who is responsible for their actions in both urban and rural perimeters. For this reason, it is important that educational entities, in all their different degrees, intensify and/or strengthen their curriculum or pensum in the Environmental Education area, or the review of the current pedagogical model and restructuration with processes of decisive teaching, framed towards the environment, with the commitment of all individuals, this education must be oriented to the sustainable development and seeking an improvement in the quality of life of citizens. The foregoing in order to transmit a series of values and habits that lead future generations to respect our natural resources and the environment. This environmental education must be replicated to our relatives and fellow citizens, by each and every one of the students of the different educational institutions, with a true environmental conscience radiating love and respect for our natural resources and the environment. The foregoing in co-responsibility as citizens with state institutions, also in charge of environmental education and environmental control in the Capital District, urban and rural areas

Diseño de mezclas de hormigones autocompactantes con alto contenido de adiciones minerales y áridos de diferentes naturaleza para desempeño en ambientes altamente agresivos

[EN] The advances in the use of self-compacting concrete (SCC) increases its consumption in construction materials. The SCC has ease of placement and refinement of the microstructure due to the increase of the volume of paste and fines thus improving the resistance to the penetration of aggressive agents. Therefore, its use is not limited to usual scenarios but focusing also to environments with severe operating conditions as is the case of energy transport infrastructures, often located in remote and extreme places. These conditions of application and location restrict the type of materials to be used in the design of concrete: type of aggregates, type of cement, use of supplementary cementitious materials (SCM), etc. The development of SCC also must imply an increase in the sustainability of the construction process by promoting the use of binders with mineral additions and limestone filler , in order to reduce the total cement content (due to the reduction of CO2 emissions associated to cement production) thus decreasing their environmental footprint. However, the incorporation of SCM implies the need to ensure compatibility with the chemical additives, superplasticizers, while maintaining the fresh state properties. Another relevant factor is the type and characteristics of aggregates that significantly affect the workability of concrete. The aggregates provide an improvement in performance in a hardened state, but in some cases they modify the consistency losing the self-compactibility of the concrete.The aim of this study is to evaluate the influence of the composition of the mixture components on the fresh and hardened properties of the SCC: 1) Interaction of the additives with cements with high mineral addition content (50%) of slag and fly ash; 2) the effect of the use of mixtures of aggregates with different origin, shape and composition that provide the special properties required concentrated solar power plants. Mixtures of aggregates, limestone, basalt and crushed Clinker have been considered along with additives that promote flowability, water reducers and density enhancement. Robust SCCs can be developed with high stability suitable for CSP application.[ES] El presente estudio se centra en el desarrollo de dosificaciones de hormigones autocompactantes (HAC) para ser empleados en la construcción de infraestructuras de almacenamiento de energía térmica. En el estudio se han considerado tres aspectos básicos: 1) selección del cemento óptimo (Binario con 50% escorias de alto horno y ternario con 20% de escorias de alto horno y 20% de cenizas volantes), 2) áridos de altas prestaciones térmicas: calizo, basáltico y Clinker de cemento, y 3) combinación de aditivos para mejorar las características de trabajabilidad, fluidez y tiempo abierto. El diseño de los hormigones se ha realizado en dos etapas: i) utilizando el método de morteros equivalentes, ii) HAC de altas prestaciones térmicas. Se ha establecido el método de morteros equivalentes como una herramienta de apoyo en la fase preliminar del estudio, en el desarrollo del hormigón. La compatibilidad de los diferentes tipos de aditivos con los cementos binarios y ternarios con alto contenido en adiciones minerales ha sido comprobada en los morteros equivalentes. Siempre la cantidad del aditivo superplastificante / Reductor de agua (SP/RA) es menor que el aditivo para mejorar la trabajabilidad (SP/T) y complementado con la Nano-sílice (NS) usada además como modulador de viscosidad. El árido basáltico mejora la fluidez, aumenta la densidad y resistencia, pero complica la trabajabilidad. El árido calizo aporta docilidad y baja la densidad. El árido de clinker mejora la trabajabilidad y aumenta la densidad. El filler calizo (FC) mejora la compacidad aunque en detrimento de las resistencias.Este estudio ha sido financiado parcialmente por el Proyecto LORCENIS, Project ID 685445 de la Comisión Europea dentro H2020. Los autores agradecen a la empresa Dyckerhoff por el suministro del cemento usado en este proyecto y a la empresa SIKA en el suministro de los aditivos.Puentes Mojica, J.; Calvo, J.; Alonso Alonso, M. (2018). Diseño de mezclas de hormigones autocompactantes con alto contenido de adiciones minerales y áridos de diferentes naturaleza para desempeño en ambientes altamente agresivos. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 177-186. https://doi.org/10.4995/HAC2018.2018.6324OCS17718

Implementing the sterile insect technique with RNA interference – a review

RNA interference (RNAi) of insect pests is reviewed and its potential for implementing Sterile Insect Technique (SIT)-related control is considered. The molecular mechanisms that support RNAi in pest species are reviewed in detail, drawing on literature from a range of species including Drosophila melanogaster and Homo sapiens. The underlying genes that enable RNAi are generally conserved across taxa, although variance exists in both their form and function. RNAi represents a plausible, non-GM system for targeting populations of insects for control purposes, if RNA interference (RNAi) effector molecules can be delivered environmentally (eRNAi). We consider studies of eRNAi from across several insect orders and review to what extent taxonomy, genetics and differing methods of double stranded (ds)RNA synthesis and delivery can influence the efficiency of gene knockdown. Several factors, including the secondary structure of the target mRNA and the specific nucleotide sequence of dsRNA effector molecules, can affect the potency of eRNAi. However, taxonomic relationships between insects cannot be used to reliably forecast the efficiency of an eRNAi response. The mechanisms by which insects acquire dsRNA from their environment require further research, but the evidence to date suggests that endocytosis and transport channels both play key roles. Delivery of RNA molecules packaged in intermediary carriers such as bacteria or nanoparticles may facilitate their entry into and through the gut, and enable the evasion of host defense systems, such as toxic pH, that would otherwise attenuate the potential for RNAi