Aggregation Methodology to Estimate Hydraulic Conductivity in Unsaturated Heterogeneous Soils

Se presenta la validación de una metodología de agregación, propuesta para obtener conductividades hidráulicas equivalentes de un medio homogéneo en suelos heterogéneos no saturados. Para ello se propone, en una primera etapa, una modelación numérica del flujo en la zona no saturada, en el dominio heterogéneo discretizado con alto grado de detalle y parametrizado mediante funciones de pedotransferencia adecuadas. En una segunda etapa se calibran los parámetros equivalentes del modelo de frente húmedo con los resultados alcanzados en la primera etapa, comparándolos con los propuestos en la metodología de agregación. El procedimiento se aplica a 68 perfiles típicos de suelos que caracterizan el sector meridional de la provincia de Santa Fe (Argentina). Los resultados alcanzados validan la metodología de agregación propuesta para un numeroso muestreo de composiciones texturales, propiedades hidráulicas y contenidos de humedad antecedente. Para las series de suelos analizadas, serían aceptables las estimaciones de conductividades hidráulicas saturadas mediante ponderación hasta saturaciones efectivas del orden del 50%, con un rango de errores acotados al 10%.This study presents the validation of an aggregation methodology proposed to obtain hydraulic conductivity equivalents for a homogeneous porous media in unsaturated heterogeneous soils. The first step in this proposal is to numerically model flow in the unsaturated zone of a heterogeneous area, with a highly detailed discretization and parameterization based on suitable pedotransfer functions. The second stage involves calibrating the equivalent parameters from the wet front model based on the results from the first phase and comparing with those proposed by the aggregation methodology. The procedure was applied to 68 soil profiles characteristic of the southern province of Santa Fe (Argentina). The results obtained validate the aggregation methodology proposed for a large sampling of textural compositions, hydraulic properties and antecedent moisture contents. For the series of soils analyzed, estimates of saturated hydraulic conductivity would be acceptable with weighting up to effective saturations of 50%, with a margin of error limited to 10%Fil: Zimmermann, Erik Daniel. Universidad Nacional de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Basile, Pedro Abel. Universidad Nacional de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Flat Foldings of Plane Graphs with Prescribed Angles and Edge Lengths

When can a plane graph with prescribed edge lengths and prescribed angles (from among $\{0,180^\circ, 360^\circ$\}) be folded flat to lie in an infinitesimally thin line, without crossings? This problem generalizes the classic theory of single-vertex flat origami with prescribed mountain-valley assignment, which corresponds to the case of a cycle graph. We characterize such flat-foldable plane graphs by two obviously necessary but also sufficient conditions, proving a conjecture made in 2001: the angles at each vertex should sum to $360^\circ$, and every face of the graph must itself be flat foldable. This characterization leads to a linear-time algorithm for testing flat foldability of plane graphs with prescribed edge lengths and angles, and a polynomial-time algorithm for counting the number of distinct folded states.Comment: 21 pages, 10 figure

Conflict-Free Coloring of Planar Graphs

A conflict-free k-coloring of a graph assigns one of k different colors to some of the vertices such that, for every vertex v, there is a color that is assigned to exactly one vertex among v and v's neighbors. Such colorings have applications in wireless networking, robotics, and geometry, and are well-studied in graph theory. Here we study the natural problem of the conflict-free chromatic number chi_CF(G) (the smallest k for which conflict-free k-colorings exist). We provide results both for closed neighborhoods N[v], for which a vertex v is a member of its neighborhood, and for open neighborhoods N(v), for which vertex v is not a member of its neighborhood. For closed neighborhoods, we prove the conflict-free variant of the famous Hadwiger Conjecture: If an arbitrary graph G does not contain K_{k+1} as a minor, then chi_CF(G) <= k. For planar graphs, we obtain a tight worst-case bound: three colors are sometimes necessary and always sufficient. We also give a complete characterization of the computational complexity of conflict-free coloring. Deciding whether chi_CF(G)<= 1 is NP-complete for planar graphs G, but polynomial for outerplanar graphs. Furthermore, deciding whether chi_CF(G)<= 2 is NP-complete for planar graphs G, but always true for outerplanar graphs. For the bicriteria problem of minimizing the number of colored vertices subject to a given bound k on the number of colors, we give a full algorithmic characterization in terms of complexity and approximation for outerplanar and planar graphs. For open neighborhoods, we show that every planar bipartite graph has a conflict-free coloring with at most four colors; on the other hand, we prove that for k in {1,2,3}, it is NP-complete to decide whether a planar bipartite graph has a conflict-free k-coloring. Moreover, we establish that any general} planar graph has a conflict-free coloring with at most eight colors.Comment: 30 pages, 17 figures; full version (to appear in SIAM Journal on Discrete Mathematics) of extended abstract that appears in Proceeedings of the Twenty-Eighth Annual ACM-SIAM Symposium on Discrete Algorithms (SODA 2017), pp. 1951-196

Do standardised prognostic algorithms reflect local practice? Application of EORTC risk tables for non-muscle invasive (pTa/pT1) bladder cancer recurrence and progression in a local cohort.

A risk calculator algorithm to allow prediction of probabilities of 1- and 5-year recurrence and progression rates in individuals with pTa/pT1 bladder cancer has been proposed by the European Organisation for Research and Treatment of Cancer (EORTC) and was incorporated into the European Association of Urology guidelines in 2006. We attempted to validate this algorithm in a cohort of patients with known outcome. Prognostic data were collected from a consecutively presenting cohort of 109 patients with non-muscle invasive (pTa/pT1) transitional cell cancer (TCC) at a single institution between 1983 and 1985. Using the same statistical models as in the EORTC original paper, predicted probabilities of 1- and 5-year recurrence and progression were calculated. Patients were divided into four risk groups for recurrence (Ir-IVr) and progression (Ip-IVp), respectively, using six prognostic criteria. These were then compared to the probabilities predicted in the EORTC algorithm. The predicted 1- and 5-year probabilities of recurrence were significantly higher in the study population as compared to the original EORTC algorithm for all four risk groups. The predicted 1-year probabilities for progression in groups Ip/IIIp and at 5-years for groups Ip/IIp were in accordance with the original algorithm, but were higher for the other progression groups. The concordance for the model of prediction using the study group for recurrence at 1 and 5 years was 62 and 63%, respectively, and for progression was 65 and 67%, respectively. We were unable to validate the proposed algorithm in our group of patients. Although our study has limitations that prevent firm conclusions on the validity of the algorithm, it does expose some of the drawbacks of standardised nomograms when applied to local clinical practice

Who witnesses The Witness? Finding witnesses in The Witness is hard and sometimes impossible

We analyze the computational complexity of the many types of pencil-and-paper-style puzzles featured in the 2016 puzzle video game The Witness. In all puzzles, the goal is to draw a simple path in a rectangular grid graph from a start vertex to a destination vertex. The different puzzle types place different constraints on the path: preventing some edges from being visited (broken edges); forcing some edges or vertices to be visited (hexagons); forcing some cells to have certain numbers of incident path edges (triangles); or forcing the regions formed by the path to be partially monochromatic (squares), have exactly two special cells (stars), or be singly covered by given shapes (polyominoes) and/or negatively counting shapes (antipolyominoes). We show that any one of these clue types (except the first) is enough to make path finding NP-complete ("witnesses exist but are hard to find"), even for rectangular boards. Furthermore, we show that a final clue type (antibody), which necessarily "cancels" the effect of another clue in the same region, makes path finding $\Sigma_2$-complete ("witnesses do not exist"), even with a single antibody (combined with many anti/polyominoes), and the problem gets no harder with many antibodies. On the positive side, we give a polynomial-time algorithm for monomino clues, by reducing to hexagon clues on the boundary of the puzzle, even in the presence of broken edges, and solving "subset Hamiltonian path" for terminals on the boundary of an embedded planar graph in polynomial time.Comment: 72 pages, 59 figures. Revised proof of Lemma 3.5. A short version of this paper appeared at the 9th International Conference on Fun with Algorithms (FUN 2018

Rigid Origami Vertices: Conditions and Forcing Sets

We develop an intrinsic necessary and sufficient condition for single-vertex origami crease patterns to be able to fold rigidly. We classify such patterns in the case where the creases are pre-assigned to be mountains and valleys as well as in the unassigned case. We also illustrate the utility of this result by applying it to the new concept of minimal forcing sets for rigid origami models, which are the smallest collection of creases that, when folded, will force all the other creases to fold in a prescribed way

Proceso administrativo y su incidencia en la toma de decisiones del personal administrativo del Hospital Quillabamba, 2020

El presente estudio tuvo como objetivo demostrar que el proceso administrativo incide en la toma de decisiones del personal administrativo del hospital Quillabamba 2020.; la investigación pertenece al enfoque cuantitativo, cuyo alcance es descriptivo – correlacional, con un diseño no experimental de tipo básico, la población de estudio de la presente investigación es de 60 personas que laboran en el área administrativa con funciones y características comunes; se aplicó el instrumento a una muestra de 53 trabajadores. Los resultados obtenidos muestran que existe una fuerte correlación positiva entre el proceso administrativo y la toma de decisiones en la institución referida, por lo que se puede continuar una nueva investigación experimental para poder modificar patrones en una de las variables para así poder corregir errores en la segunda. En conclusión, existe un fuerte grado de correlación positiva entre ambas variables de estudio

La planeación financiera y la rentabilidad de las Cajas Municipales de Ahorro y Crédito de Pichanaqui en el año 2017

La presente investigación tuvo como problema general ¿Qué relación existe entre la Planeación Financiera y la Rentabilidad de las Cajas Municipales del distrito de Pichanaqui, provincia de Chanchamayo en el año 2017?, consecuentemente se formuló nuestro objetivo general: Establecer la relación que tiene la Planeación Financiera y la Rentabilidad de las Cajas Municipales del distrito de Pichanaqui en el año 2017. Finalmente, se planteó la hipótesis general siguiente: Existe relación directa entre la Planeación Financiera y la Rentabilidad de las Cajas Municipales del distrito de Pichanaqui en el año 2017. Para el logro del objetivo y la prueba de hipótesis, se empleó el enfoque cuantitativo, el método fue el científico, de tipo aplicada, de nivel correlacional y de diseño no experimental, nuestra población fueron 8 Cajas Municipales de Ahorro y Crédito del distrito de Pichanaqui, nuestra muestra fué el no probabilístico, es decir se tomaron al total de la población, para la medir las variables se empleó el Cuestionario, en la escala de tipo Likerth, los cuales fueron sometidos a la validación de juicio de expertos, la confiabilidad fue determinada por el estadístico Alpha de Combrach. Para la variable independiente fue de 0,954 y para la dependiente 0.950. Finalmente, mi principal conclusión fue que Existe relación directa alta entre la Planeación Financiera y la Rentabilidad de las Cajas Municipales del distrito de Pichanaqui, provincia de Chanchamayo en el año 2017. Corroborada con un “r” = 0,966Tesi

Extracorporeal Membrane Oxygenation for Complex Multiorgan System Trauma

With growing experience, the indications for salvage extracorporeal membrane oxygenation continue to expand. We describe a successful application of extracorporeal support in a polytrauma patient presenting with profound hypothermia, respiratory failure, and whom was later found to have an intracranial hemorrhage. We advocate the role of salvage therapy even in patients with complex pathophysiology despite perceived relative or absolute contraindications to extracorporeal support

Nonconvective Forces: A Critical and Often Ignored Component in the Echocardiographic Assessment of Transvalvular Pressure Gradients

Echocardiography is routinely used to assess ventricular and valvular function, particularly in patients with known or suspected cardiac disease and who have evidence of hemodynamic compromise. A cornerstone to the use of echocardiographic imaging is not only the qualitative assessment, but also the quantitative Doppler-derived velocity characteristics of intracardiac blood flow. While simplified equations, such as the modified Bernoulli equation, are used to estimate intracardiac pressure gradients based upon Doppler velocity data, these modified equations are based upon assumptions of the varying contributions of the different forces that contribute to blood flow. Unfortunately, the assumptions can result in significant miscalculations in determining a gradient if not completely understood or they are misapplied. We briefly summarize the principles of fluid dynamics that are used clinically with some of the inherent limitations of routine broad application of the simplified Bernoulli equation