Multiscale mass transport in z~6 galactic discs: fueling black holes

By using AMR cosmological hydrodynamic N-body zoom-in simulations, with the RAMSES code, we studied the mass transport processes onto galactic nuclei from high redshift up to $z\sim6$. Due to the large dynamical range of the simulations we were able to study the mass accretion process on scales from $\sim50[kpc]$ to $\sim$ few $1[pc]$. We studied the BH growth on to the galactic center in relation with the mass transport processes associated to both the Reynolds stress and the gravitational stress on the disc. Such methodology allowed us to identify the main mass transport process as a function of the scales of the problem. We found that in simulations that include radiative cooling and SNe feedback, the SMBH grows at the Eddington limit for some periods of time presenting $\langle f_{EDD}\rangle\approx 0.5$ throughout its evolution. The $\alpha$ parameter is dominated by the Reynolds term, $\alpha_R$, with $\alpha_R\gg 1$. The gravitational part of the $\alpha$ parameter, $\alpha_G$, has an increasing trend toward the galactic center at higher redshifts, with values $\alpha_G\sim 1$ at radii <$\sim$ few $10^1[pc]$ contributing to the BH fueling. In terms of torques, we also found that gravity has an increasing contribution toward the galactic center at earlier epochs with a mixed contribution above $\sim 100 [pc]$. This complementary work between pressure gradients and gravitational potential gradients allows an efficient mass transport on the disc with average mass accretion rates of the order $\sim$ few $1 [M_{\odot}/yr]$. These level of SMBH accretion rates found in our cosmological simulations are needed in all models of SMBH growth that attempt to explain the formation of redshift $6-7$ quasars

Remarks on the stability of Cartesian PMLs in corners

This work is a contribution to the understanding of the question of stability of Perfectly Matched Layers (PMLs) in corners, at continuous and discrete levels. First, stability results are presented for the Cartesian PMLs associated to a general first-order hyperbolic system. Then, in the context of the pressure-velocity formulation of the acoustic wave propagation, an unsplit PML formulation is discretized with spectral mixed finite elements in space and finite differences in time. It is shown, through the stability analysis of two different schemes, how a bad choice of the time discretization can deteriorate the CFL stability condition. Some numerical results are finally presented to illustrate these stability results

Sequential Organ Failure Assessment score, Mortality in Emergency Department Sepsis score y National Early Warning score como predictores de mortalidad intrahospitalaria en sepsis

Determinar si es el SOFA, o el MEDS o el NEWS, el sistema de puntaje con mayor capacidad discriminativa como predictor de mortalidad intrahospitalaria en sepsis. MATERIAL Y MÉTODOS: Se realizó un estudio de prueba diagnóstica, observacional y retrospectivo. La muestra estuvo formada por un grupo emparejado de 162 pacientes adultos sépticos según criterio sepsis – 3. Las historias clínicas fueron seleccionadas por muestreo aleatorio simple. Se comparó los sistemas de puntuación usando el valor de sus áreas bajo la curva de característica operativa del receptor (AUC). Además se determinó los puntos de corte óptimos para cada sistema y los valores de sensibilidad y especificidad correspondientes a los mismos. RESULTADOS: Los AUROC obtenidos fueron 0,81 (IC 95%: 0,74 – 0,88) para el NEWS, 0,79 (IC 95%: 0,71 – 0,86) para el SOFA y 0,77 (IC 95%: 0,69 – 0,84) para el MEDS. Todas las comparaciones entre áreas obtuvieron un p>0,05. Los puntos de corte óptimo fueron calculados en ≥10 para el NEWS, ≥5 para el SOFA y ≥13 para el MEDS. Los valores de sensibilidad y especificidad calculados para dichos puntos fueron 76,36% con 71,96% para el NEWS, 74,55% con 71,96% para el SOFA y 50,91% con 89,72% para el MEDS. Dos variables intervinientes tuvieron significancia estadística: La presencia de shosk séptico y el uso de antibioticoterapia dirigida. CONCLUSIONES: No existen diferencias estadísticas entre las capacidades discriminativas como predictores de mortalidad intrahospitalaria en sepsis en los sistemas de puntaje evaluados.To determinate if it is the SOFA, the MEDS or the NEWS the scoring system with the greatest discriminative capacity as predictor of in-hospital mortality in sepsis. MATERIAL AND METHODS: A retrospective observational diagnostic test study was performed. The research sample was a paired sample of 162 septic patients according to sepsis – 3 criteria. The clinical histories were selected by simple random sampling. The scoring systems were compared using the value of each of their area under receiver operating characteristic curve (AUC). Also, the optimal cut – off points (optimal decision threshold) and their corresponding sensitivity and specificity values were calculated for each scoring system. RESULTS: The obtained AUROC were 0.81 (IC 95%: 0.74 – 0.88) for NEWS, 0.79 (IC 95%: 0.71 – 0.86) for SOFA and 0.77 (IC 95%: 0.69 – 0.84) for MEDS. All area comparisons obtained a p>0.05. The optimal cut – off points were calculated in ≥10 for NEWS, ≥5 for SOFA and ≥13 for MEDS. The calculated sensitivity and specificity for those points were 76.36% with 71.96% for NEWS, 74.55% with 71.96% for SOFA and 50.91% with 89.72% for MEDS. Two intervening variables had statistical significance: the developing of septic shock, and the use of pathogen directed antibiotic therapy. CONCLUSIONS: There is no statistical difference between the discriminative capacities as predictors of in-hospital mortality in sepsis in the evaluated scoring systems.Tesi

Inversor multinivel con reducción de pérdidas por conmutación

Actualmente en la industria son utilizados dos tipos de inversores, unos con conmutación en baja frecuencia y otros con conmutación en alta frecuencia por medio de PWM. Aquellos que manejan conmutación en baja frecuencia se caracterizan por que eliminan los armónicos más bajos por suma, así mismo eliminan contenido de frecuencia baja por medio de un filtro en la salida que se caracteriza por ser de impedancia alta. Debido a la baja frecuencia que manejan estos inversores en la conmutación, las perdidas asociadas a esta son bajas. Mientras que aquellos inversores que manejan alta frecuencia, eliminan contenido armónico por conmutación, permitiendo que el filtro a la salida sea de menor impedancia, pero generando mayores pérdidas en el inversor, reduciendo su eficiencia se propuso diseñar e implementar una nueva topología de un inversor el cual eliminara cierta cantidad de armónicos por conmutación en baja frecuencia utilizando dos puentes H, y utilizar un tercer puente H el cual al ser conmutado en alta frecuencia eliminaría los armónicos restantes obteniendo a la salida de los tres puentes una señal seno modulada, de la cual obtendríamos el promedio movil tras ser pasada por un filtro pasa bajos, resultando de este modo la señal sinusoidal deseada.Currently in the industry are used two types of investors, low frequency switching and others with high switching frequency using PWM. Those handling low frequency switching are characterized by eliminating the lowest harmonics by summation, also eliminates low frequency content by a filter on the output that is characterized by high impedance . Due to the low frequency handling these investors in the switching losses associated with this are low. While investors who handle high frequency harmonic content removed switched , allowing the filter to the output impedance is smaller , but larger losses in the inverter , reducing its efficiency is proposed to design and implement a new topology of an investor 's which eliminate certain amount of harmonics by switching at low frequencies using two H bridges, and H use a third bridge which to be switched in high frequency harmonics would eliminate remaining obtaining at the outlet of the three bridges sine modulated signal , which would obtain the moving average after being passed through a low pass filter , thus resulting the desired sinusoidal signal.Ingeniero (a) ElectrónicoPregrad

Tolerance Management of Aluminum-Framed Curtain Wall Systems: A Case Study

The aluminum-framed curtain wall is one of the most applied building cladding systems due to its versatility and reasonable costs for low to high-rise constructions. The curtain wall system demands high-quality control and proper tolerance management with other building components to achieve adequate performance. However, the fragmented nature of the construction industry often results in poor interface management and creates problems making the installation process inefficient. Most sections in the construction industry have been utilizing emerging Information and Communication Technologies (ICT), including Building Information Modeling (BIM), to enhance communication and remove clashes between building components in advance. However, those practitioners working on the curtain wall installation do not appear to communicate effectively with project participants to resolve clashes between the curtain wall and other building components in advance. Therefore, they still experience low productivity in curtain wall installation. What does hinder curtain wall subcontractors from utilizing ICT to enhance communication between parties in the course of the curtain wall installation? In response to the question, this study monitored the curtain wall installation process of one commercial building construction project in Texas. It also interviewed key practitioners with semi-structured open questions, to gain an in-depth understanding of the issues that may affect their productivity. The results show that the general contractor nor the cladding subcontractors working for the target project see the immediate need of using ICT to solve clashes between cladding components. They thought the interface between cladding systems was not as complex as other building components such as mechanical, electrical and plumbing systems. The cladding subcontractors did not want to invest resources in adopting the ICT or hiring a third party to provide the service, because they were not sure if the use of ICT would guarantee the productivity improvement in the field. The interviewees recognized the overall productivity improvement that the construction industry gained from using ICT. They also admitted that the use of ICT may help them better manage the interface issues in cladding installation. However, the need of front-end investment and their doubts about the impact on the field crews hindered them from trying to use ICT in the course of the cladding installation process

Efecto del cambio en el uso del suelo sobre la incidencia del accidente ofídico provocado por Bothrops asper y Porthidium lansbergii (Serpentes: Viperidae) en el departamento de Antioquia, Colombia

Los accidentes ofídicos se consideran una enfermedad desatendida y un grave problema de salud pública debido a las tasas de morbilidad/mortalidad, el difícil acceso a los servicios de salud y la escasez de suero antiofídico, especialmente en países tropicales. La pérdida y degradación de hábitat es actualmente la presión más común sobre la biodiversidad, afectando la estructura de las comunidades ecológicas locales conduciendo a cambios en la distribución y abundancia, propiciando así conflictos entre la fauna y seres humanos. Por esta razón, se analizaron los efectos del cambio en el uso del suelo sobre la incidencia del accidente ofídico provocado por Bothrops asper y Porthidium lansbergii en Antioquia . Para estimar la distribución potencial de B. asper y P. lansbergii y determinar la variable ambiental que más influye en su distribución se realizó modelamiento de nicho ; además, se llevó a cabo un análisis multitemporal descriptivo a través del análisis de imágenes satelitales; y se construyó un modelo a futuro de la distribución potencial de estas serpientes para Antioquia. la resolución de los datos espaciales no permitió concluir que el cambio en el uso del suelo tiene una relación directa con las mordeduras de serpiente. Se requieren datos geográficos más precisos basados en coordenadas verificables para comprender mejor la distribución actual y futura de estas víboras en Antioquia. Los análisis implementados aquí son herramientas útiles para mejorar las medidas de control y prevención del accidente ofídico debido a la drástica transformación del paisaje que se produce actualmente en los países tropicalesAbstract: Snakebite accidents are considered to be an unattended disease and a serious public health problem due to morbidity/mortality rates, poor access to health services and the shortage of Antiveno m, especially in tropical countries. Habitat loss and fragmentation, is currently the most common pressure on biodiversity, affecting the structure of local ecological communities leading to changes in distribution and abundance bringing on conflicts betwe en fauna and humans. For this reason, it is necessary to analyze the effects of land use changes on the incidence of the ophidian accident caused by Bothrops asper and Porthidium lansbergii, which are the two snakes that most accidents cause in Antioquia. In order to estimate the potential distribution of B. asper and P. lansbergii and to determine the environmental variable that most influences the ir distribution , ecological niche modelling was used; in addition, a multitemporal analysis was carried out through the analysis of satellite images; a future mode l of the potential distribution of these snakes was constructed for Antioquia. Spatial data resolution did not allow us to conclude that land use change has an explicit relation to snakebites. More accurate geographical data based on verifiable coordinates is required to better understand the present and future distribution of these vipers in Antioquia. A nalyses implemented here are useful tools to improve control and prevention measures of snake bite accident due to landscape transformation that drastically occurs in tropical countries.Maestrí

Cauda Equina Syndrome Caused by Spinal Dural Arteriovenous Fistula

Spinal dural arteriovenous fistula (SDAVF) is rare but still the most commonly encountered vascular malformation of the spinal cord. A 31-year-old male developed gait disturbance due to weakness of his lower extremities, voiding difficulty and sexual dysfunction with a progressive course since 3 months. He showed areflexia in both knees and ankles. Electromyographic findings were suggestive of multiple root lesions involving bilateral L2 to S4 roots of moderate degree. Magnetic resonance images showed high signal intensity with an ill-defined margin in T2-weighted images and intensely enhanced by a contrast agent through the lumbosacral spinal cord. Selective spinal angiography confirmed a dural arteriovenous fistula with a nidus at the L2 vertebral level. After selective endovascular embolization, his symptoms drastically improved except sexual dysfunction. We report a rare case of cauda equina syndrome due to spinal arteriovenous fistula with drastic improvement after endovascular embolization

Water-Rock Interactions and Seasonal Hydrologic Processes in Constructed Everglades Tree Islands

The decline of tree islands in the freshwater-Everglades wetland because of hydrologic manipulation, has compromised valuable ecosystem services. Although the role of tree islands in maintaining freshwater quality stems largely from evapotranspiration processes, fundamental questions remain about the effects of different geologic materials on their hydrogeochemical functioning. To reduce this uncertainty, the lithological composition of a set of man-made tree islands was investigated coupled with long-term hydrologic and hydrochemical data. Key results indicate that limestone substrates and peat substrates with elevated proportions of sand, facilitated surface water-groundwater interactions and mineral dissolution. However, limestone-based islands were more effective in lowering the water table and concentrating solutes in response to evapotranspiration during low surface water stages. Additionally, the peat substrate of an island with low sand content favored the thermodynamic conditions for calcite accumulation in the phreatic zone, while phosphorus concentrations in the groundwater were associated with the breakdown of organic matter

Actividad multicultural New York - Miami

Artículo de investigación -reflexiónSe describe una serie de vivencias realizadas del día 23 de noviembre a 30 de noviembre en Estados Unidos, en las ciudades de New York y Miami. Con el fin de lograr determinar las características de una cultura internacional, visitar compañías establecidas y participar en las charlas propuestas por la Universidad Católica en compañía de la Universidad San Ignacio de Miami y de la Universidad de la FIU de Argentina.INTRODUCCIÓN 1. Consulado de New York 2. Found Fundación Center 3. Naciones Unidas 4. Servientrega Estados Unidos 5. Puerto de Miami 6. Logistics & Supply Management 7. Super Nice Rent a Car BIBLIOGRAFÍAEspecializaciónEspecialista en Análisis y Administración Financier