The micropolar Navier-Stokes equations: A priori error analysis

The unsteady Micropolar Navier-Stokes Equations (MNSE) are a system of parabolic partial differential equations coupling linear velocity and pressure with angular velocity: material particles have both translational and rotational degrees of freedom. We propose and analyze a first order semi-implicit fully-discrete scheme for the MNSE, which decouples the computation of the linear and angular velocities, is unconditionally stable and delivers optimal convergence rates under assumptions analogous to those used for the Navier-Stokes equations. With the help of our scheme we explore some qualitative properties of the MNSE related to ferrofluid manipulation and pumping. Finally, we propose a second order scheme and show that it is almost unconditionally stable

Assessing the Potential Impact of Sugarcane Varieties and Predation on Diatraea Saccharalis (F.) Populations in Southern Louisiana.

To facilitate a better understanding of how varietal resistance and predation affect area-wide sugarcane borer populations, several studies were undertaken before the development of a simulation model. The first study was a 3-year investigation into the compatibility and contributions of varietal resistance, arthropod predation and insecticide toward sugarcane borer control. Insecticides were shown to be the predominant management factor preventing plant injury, but varietal resistance appeared nearly as important in terms of sugarcane borer population regulation in sugarcane. The next study assessed a moth production index in addition to the percentage of bored internodes as a tool for quantifying varietal resistance to the sugarcane borer. Resistance ratings based on the percentage of bored internodes were proven to be inadequate estimators of moth emergence due to differences in sugarcane borer survival after entry into the stalk. The third study investigated the fecundity of the sugarcane borer with larval development on four gramineous hosts. A single linear regression on female pupal weight was obtained to predict fecundity regardless of the host for larval development. The simulation model included processes of immature development, oviposition, host-dependent mortality and mortality due to arthropod predation. Varietal parameters in the model were obtained from small-plot varietal evaluations. Percentages of bored internodes were used to compare survival of sugarcane borer eggs until establishment in the stalk among sugarcane cultivars with and without predator suppression. To estimate survival among cultivars, from establishment in the stalk until pupation, a relative survival index was utilized. Simulations showed that differences in moth emergence and total emergence were greatest when there was no exchange of adults among varieties. Simulations indicated that the impact of susceptible varieties on sugarcane borer populations can be mitigated if these varieties are properly dispersed among varieties with greater resistance. Relatively small differences observed in small plot varietal evaluations were magnified during the simulations when amount of adult redistribution among varieties was reduced (i.e. grown in larger continuous plantings). Thus, results obtained from small plot varietal resistance evaluations alone do not adequately address the potential role that varieties may have on pest populations when grown on larger acreages

An Integrated Structural Analysis on Seismic of a Paleo Mound Development (Woolsey Mound, Northern Gulf of Mexico)

Woolsey Mound is ~1 km diameter thermogenic gas hydrate and cold seep (GHCS) complex system. It is located at ~900 m water depth in the Mississippi Canyon Lease Block 118 (MC–118) on the upper continental slope of the northern Gulf of Mexico (GOM). Due to its complex geology, widespread hydrate seepage activity and presence of benthic habitat, the mound serves as a permanent research site for a multidisciplinary seafloor observatory, thus providing insights into the dynamics of shallow fluid expulsion, their spatial and time variations and possible geological forcing mechanisms. This study utilizes a set of high resolution 2D autonomous underwater vehicle (AUV) borne chirp seismic data acquired at MC–118, and it provides a unique basis for a twofold detailed structural characterization of an interpreted paleo mound development (PMD). The profiler gives ~50 m of subbottom penetration with ~0.1 m of vertical resolution. First, isochore analysis of deeper stratigraphy suggests 1) uniform sedimentation prior to and post PMD with strata variance of ~0.5-1 m, and 2) uneven sediment distribution during PMD activity, showing a localized growth strata or differential subsidence of ~5-6 m, as well as truncation and onlapping synkinematic geometry. In addition, integration with modern chronostratigraphic results further indicates that PMD is correlative to relative sea level highstands, of mid-Late Pleistocene. Second, PMD appears to have occurred during quiescent tectonic environment as evidenced by a constant offset of ~1-2 m throughout stratigraphy, along major faults. These data may substantiate that Woolsey Mound cold seeps are ‘episodic’, and that sea level fluctuation or tectonic governance alone may not be critical geological triggers of seepage development

Análisis no-lineal de nudos de concreto sin refuerzo.

Introduction- Reinforced Concrete Frames (RCF) constitute a significant portion of the building stock in areas with seismic hazard. Many older buildings of this type were designed and constructed with little or no consideration of lateral load effects. When not properly designed, the Beam-Column Joints (BCJ) can be the weak links in the RCF. Unreinforced BCJ are still quite prevalent in older-type construction especially in Asia and Latin America. The unreinforced BCJ are key components that have a significant impact on the structure’s behavior of RCF. Regarding the analytical approaches applicable to BCJ, the approaches range from simplified to more elaborate and phenomenological-oriented. Unfortunately, most of them lack of simplicity, numerical stability and practicality to robustly evaluate the performance of unreinforced BCJ. This paper presents an analytical approach to modeling unreinforced BCJ. Objective- The aim of this paper is to present a modified modeling approach to simulate the nonlinear behavior of unreinforced BCJ in RCF structures. Method- The approach presented is based on the model presented in [1]. The model was modified to follow the same nomenclature of the [2]. In the proposed approach, the BCJ subassembly is represented by (1) a set of rigid links placed in cross-shape are used to represent the joint geometry, (2) a zero-length element with an empirical quad-backbone curve, placed at the middle point of the rigid links, to represent the joint shear behavior, and (3) columns and beams elements modeled with fiber formulation and five integration points to capture the material nonlinearity of the elements that frame into the joint. The approach was implemented in the OpenSEES platform, and this was validated with 13 test results of unreinforced BCJ documented in the literature. Results- The proposed modelling approach can satisfactorily predict the joint shear capacity. A 2% difference and a standard deviation of about 11% were obtained when compared to 13 test results of unreinforced BCJ documented in the literature. In terms of cyclic behavior, the proposed modelling approach shown to adequately capture the initial stiffness, strength degradation, reloading stiffness, pre-capping, and post-capping capacity. Conclusions- The method proposed presents satisfactory agreement with the test results analyzed. Taking into account the minor modifications applied to the proposed method and the uncertainties associated with the materials, test measurements, test setup, and the tolerances, the proposed method can satisfactorily predict the unreinforced BCJ shear capacity in RCF structures. It is assumed that the procedures presented here will contribute in the incorporation of the unreinforced BCJ flexibility when modeling older-type RCF construction in a pragmatic manner.Introducción- El Sistema estructural Pórticos de Concreto Reforzado (PCR) constituye una parte significativa del inventario de edificaciones en zonas sísmicamente activas en el mundo. Muchas de las edificaciones construidas antes de la década de los 80’s fueron diseñadas y construidas con poca, o ninguna consideración de cargas sísmicas. Cuando el nudo de concreto reforzado no se ha diseñado competentemente puede convertirse en el eslabón débil del sistemas de PCR. La presencia de nudos sin refuerzo, aun es común en países emergentes localizados en Asia y América Latina. Los nudos tienen un impacto significativo en el comportamiento de PCR. Las metodologías relacionadas con el análisis de nudos de concreto pueden catalogarse como aproximadas, o muy complejas, o de enfoque fenomenológico. Desafortunadamente la mayoría de ellas carece de la simplicidad, estabilidad, y practicidad requerida para evaluar el comportamiento de los nudos en PCR.  Este artículo presenta una alternativa analítica aplicable a este tipo de elementos estructurales. Objetivo- El propósito del presente artículo es presentar un método analítico modificado aplicable al análisis no lineal de nudos no reforzados en estructuras de PCR. Metodología- El método presentado se basa en el trabajo analítico y experimental encontrado en [1], el cual es modificado para seguir exactamente la nomenclatura de [2]. En el modelo analítico, el nudo es representado a través de: (1) elementos rígidos en cruz para idealizar la geometría del nudo, (2) un resorte rotacional con una curva empírica de comportamiento tetra-lineal localizado en la mitad de los elementos rígidos para representar el comportamiento en cortante del nudo, y (3) las vigas y columnas que llegan al nudos, son modeladas con análisis seccional basado en fibras, con 5 puntos de integración; con la finalidad de incorporar el comportamiento no-lineal de los elementos que llegan al nudo. El modelo propuesto fue implementado en la plataforma OpenSEES y al mismo tiempo se validó con el resultado de 13 ensayos de laboratorio encontrados en la literatura de nudos carentes de acero de refuerzo. Resultados- El modelo propuesto puede capturar adecuadamente la capacidad a cortante del nudo. Al comparar los resultados analíticos con 13 resultados de nudos de concreto encontrados en la literatura, se encontró una diferencia en la capacidad del 2% con una desviación estándar del 11%. En relación al comportamiento del nudo ante carga cíclica se observó que se captura en forma adecuada: la rigidez inicial, resistencia, degradación de la resistencia, rigidez de recarga y capacidad antes y después del pico de resistencia. Conclusiones- El método propuesto presenta una adecuada correlación con los resultados de laboratorio estudiados. La metodología propuesta competentemente captura la capacidad del nudo a cortante, a pesar de las modificaciones incorporadas, sin mencionar las incertidumbres asociadas a los materiales, resultados de laboratorio, y tolerancias. Se espera que el procedimiento presentado en el presente documento contribuya, de una forma práctica, en la incorporación de la flexibilidad del nudo en PCR diseñados primariamente para cargas gravitacionales

Vectorizing and distributing number-theoretic transform to count Goldbach partitions on Arm-based supercomputers

In this article, we explore the usage of scalable vector extension (SVE) to vectorize number-theoretic transforms (NTTs). In particular, we show that 64-bit modular arithmetic operations, including modular multiplication, can be efficiently implemented with SVE instructions. The vectorization of NTT loops and kernels involving 64-bit modular operations was not possible in previous Arm-based single instruction multiple data architectures since these architectures lacked crucial instructions to efficiently implement modular multiplication. We test and evaluate our SVE implementation on the A64FX processor in an HPE Apollo 80 system. Furthermore, we implement a distributed NTT for the computation of large-scale exact integer convolutions. We evaluate this transform on HPE Apollo 70, Cray XC50, HPE Apollo 80, and HPE Cray EX systems, where we demonstrate good scalability to thousands of cores. Finally, we describe how these methods can be utilized to count the number of Goldbach partitions of all even numbers to large limits. We present some preliminary results concerning this problem, in particular a histogram of the number of Goldbach partitions of the even numbers up to 2 40.</p

El City Manager en la administración 2016-2018, un estudio comparativo Miguel Hidalgo, Texcoco

El estudio del gobierno local cobra notabilidad en nuestros días debido a que las administraciones locales presentan faltas en la eficiencia y eficacia de sus políticas, así como en la legitimidad de su actuar institucional, esto en gran medida, a la deficiencia de la gestión administrativa por parte del presidente municipal. En este sentido se propone una figura que coadyuve en la gestión pública del gobierno local, por tal motivo, nos cuestionamos si la ¿La implementación Institucional del City Manager o Administrador Municipal y su especificidad en la gestión administrativa mejora la eficiencia, eficacia y la legitimidad de la gestión pública de la Delegación Miguel Hidalgo, Ciudad de México y del Municipio de Texcoco, Estado de México, 2016-2018? Por dicha razón, se considera como hipótesis de esta investigación que la implementación institucional del City Manager o Administrador Municipal y su especificidad en la gestión administrativa, mejora la eficiencia, la eficacia y la legitimidad en la actual administración de la Delegación Miguel Hidalgo y el Municipio de Texcoco, Estado de México, esto debido a que la gestión administrativa recae sobre un funcionario especializado

Trifocal Relative Pose from Lines at Points and its Efficient Solution

We present a new minimal problem for relative pose estimation mixing point features with lines incident at points observed in three views and its efficient homotopy continuation solver. We demonstrate the generality of the approach by analyzing and solving an additional problem with mixed point and line correspondences in three views. The minimal problems include correspondences of (i) three points and one line and (ii) three points and two lines through two of the points which is reported and analyzed here for the first time. These are difficult to solve, as they have 216 and - as shown here - 312 solutions, but cover important practical situations when line and point features appear together, e.g., in urban scenes or when observing curves. We demonstrate that even such difficult problems can be solved robustly using a suitable homotopy continuation technique and we provide an implementation optimized for minimal problems that can be integrated into engineering applications. Our simulated and real experiments demonstrate our solvers in the camera geometry computation task in structure from motion. We show that new solvers allow for reconstructing challenging scenes where the standard two-view initialization of structure from motion fails.Comment: This material is based upon work supported by the National Science Foundation under Grant No. DMS-1439786 while most authors were in residence at Brown University's Institute for Computational and Experimental Research in Mathematics -- ICERM, in Providence, R

Invasive american mink mustela vison in wetlands of the cape horn biosphere reserve, southern Chile: What are they eating?

The impact of alien American mink on the native fauna of oceanic islands has been demonstrated in a number of locations. In the sub-Antarctic Cape Horn Biosphere Reserve of southern Chile the species is currently expanding in an area where the native fauna evolved in the absence of terrestrial predators. To evaluate any emerging problems we therefore investigated seasonal variation in prey use by mink on Navarino Island within the Reserve. We identified undigested remains in 414 scats collected from the shores of 27 ponds over JanuaryNovember 2006. Diet consisted mainly of mammals and birds. Mammals, including both native and exotic rodents, were the predominant prey in all seasons but birds were of equal importance during the summer (when birds breed and their abundance and diversity increases on the island). Exotic rodents were the only identifiable mammalian prey item during winter. Native wetland birds constituted a substantial proportion of mink diet, and greater than that reported in other areas. Many birds breeding on Navarino Island are ground-nesting, a strategy that evolved in the absence of native mammalian predators. Considering the international importance of this region, our results emphasize the need for an assessment of the impact of mink predation on the populations of native prey.Fil: Ibarra, Jose Tomas. Pontificia Universidad Católica de Chile; ChileFil: Fasola, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. University of Oxford; Reino UnidoFil: Macdonald, David W.. University of Oxford; Reino UnidoFil: Ricardo, Rozzi. Universidad de Magallanes; ChileFil: Cristián, Bonacic. Pontificia Universidad Católica de Chile; Chil