Modeling an Aquifer: Numerical Solution to the Groundwater Flow Equation

We present a model of groundwater dynamics under stationary flow and governed by Darcy's Law of water motion through porous media, we apply it to study a 2D aquifer with water table of constant slope comprised of an homogeneous and isotropic media, the more realistic case of an homogeneous anisotropic soil is also considered. Taking into account some geophysical parameters we develop a computational routine, in the Finite Difference Method, that solves the resulting elliptic partial equation, both in a homogeneous isotropic and homogeneous anisotropic media. After calibration of the numerical model, this routine is used to begin a study of the Ayamonte-Huelva aquifer in Spain, a modest analysis of the system is given, we compute the average discharge vector as well as its root mean square as a first predictive approximation of the flux in this system, providing us a signal of the location of best exploitation; long term goal is to develop a complete computational tool for the analysis of groundwater dynamics.Comment: 13 pages and 12 figure

Historia de la gráfica editorial en Mexicali a través de las tarjetas postales durante los primeros 27 años de su fundación

Este texto es producto de la investigación titulada Gráfica editorial en Mexicali, y aborda la contextualización de la producción gráfica de la ciudad a partir de su ubicación, las características específicas de la frontera Norte de México y la influencia de Estados Unidos de América. Se investiga la labor realizada por antecesores de los diseñadores y los principales de la cultura en Mexicali durante los primeros 27 años de vida (1903-1930) para entender el impacto uso y aplicación de las Tarjetas postales, abordándose desde los motivos socioculturales y económicos que provocaron un aumento en la demanda que puso en marcha al sector gráfico

Crop plant reconstruction and feature extraction based on 3-D vision

3-D imaging is increasingly affordable and offers new possibilities for a more efficient agricul-tural practice with the use of highly advances technological devices. Some reasons contrib-uting to this possibility include the continuous increase in computer processing power, the de-crease in cost and size of electronics, the increase in solid state illumination efficiency and the need for greater knowledge and care of the individual crops. The implementation of 3-D im-aging systems in agriculture is impeded by the economic justification of using expensive de-vices for producing relative low-cost seasonal products. However, this may no longer be true since low-cost 3-D sensors, such as the one used in this work, with advance technical capabili-ties are already available. The aim of this cumulative dissertation was to develop new methodologies to reconstruct the 3-D shape of agricultural environment in order to recognized and quantitatively describe struc-tures, in this case: maize plants, for agricultural applications such as plant breeding and preci-sion farming. To fulfil this aim a comprehensive review of the 3-D imaging systems in agricul-tural applications was done to select a sensor that was affordable and has not been fully inves-tigated in agricultural environments. A low-cost TOF sensor was selected to obtain 3-D data of maize plants and a new adaptive methodology was proposed for point cloud rigid registra-tion and stitching. The resulting maize 3-D point clouds were highly dense and generated in a cost-effective manner. The validation of the methodology showed that the plants were recon-structed with high accuracies and the qualitative analysis showed the visual variability of the plants depending on the 3-D perspective view. The generated point cloud was used to obtain information about the plant parameters (stem position and plant height) in order to quantita-tively describe the plant. The resulting plant stem positions were estimated with an average mean error and standard deviation of 27 mm and 14 mm, respectively. Additionally, meaning-ful information about the plant height profile was also provided, with an average overall mean error of 8.7 mm. Since the maize plants considered in this research were highly heterogeneous in height, some of them had folded leaves and were planted with standard deviations that emulate the real performance of a seeder; it can be said that the experimental maize setup was a difficult scenario. Therefore, a better performance, for both, plant stem position and height estimation could be expected for a maize field in better conditions. Finally, having a 3-D re-construction of the maize plants using a cost-effective sensor, mounted on a small electric-motor-driven robotic platform, means that the cost (either economic, energetic or time) of gen-erating every point in the point cloud is greatly reduced compared with previous researches.Die 3D-Bilderfassung ist zunehmend kostengünstiger geworden und bietet neue Möglichkeiten für eine effizientere landwirtschaftliche Praxis durch den Einsatz hochentwickelter technologischer Geräte. Einige Gründe, die diese ermöglichen, ist das kontinuierliche Wachstum der Computerrechenleistung, die Kostenreduktion und Miniaturisierung der Elektronik, die erhöhte Beleuchtungseffizienz und die Notwendigkeit einer besseren Kenntnis und Pflege der einzelnen Pflanzen. Die Implementierung von 3-D-Sensoren in der Landwirtschaft wird durch die wirtschaftliche Rechtfertigung der Verwendung teurer Geräte zur Herstellung von kostengünstigen Saisonprodukten verhindert. Dies ist jedoch nicht mehr länger der Fall, da kostengünstige 3-D-Sensoren, bereits verfügbar sind. Wie derjenige dier in dieser Arbeit verwendet wurde. Das Ziel dieser kumulativen Dissertation war, neue Methoden für die Visualisierung die 3-D-Form der landwirtschaftlichen Umgebung zu entwickeln, um Strukturen quantitativ zu beschreiben: in diesem Fall Maispflanzen für landwirtschaftliche Anwendungen wie Pflanzenzüchtung und Precision Farming zu erkennen. Damit dieses Ziel erreicht wird, wurde eine umfassende Überprüfung der 3D-Bildgebungssysteme in landwirtschaftlichen Anwendungen durchgeführt, um einen Sensor auszuwählen, der erschwinglich und in landwirtschaftlichen Umgebungen noch nicht ausgiebig getestet wurde. Ein kostengünstiger TOF-Sensor wurde ausgewählt, um 3-D-Daten von Maispflanzen zu erhalten und eine neue adaptive Methodik wurde für die Ausrichtung von Punktwolken vorgeschlagen. Die resultierenden Mais-3-D-Punktwolken hatten eine hohe Punktedichte und waren in einer kosteneffektiven Weise erzeugt worden. Die Validierung der Methodik zeigte, dass die Pflanzen mit hoher Genauigkeit rekonstruiert wurden und die qualitative Analyse die visuelle Variabilität der Pflanzen in Abhängigkeit der 3-D-Perspektive zeigte. Die erzeugte Punktwolke wurde verwendet, um Informationen über die Pflanzenparameter (Stammposition und Pflanzenhöhe) zu erhalten, die die Pflanze quantitativ beschreibt. Die resultierenden Pflanzenstammpositionen wurden mit einem durchschnittlichen mittleren Fehler und einer Standardabweichung von 27 mm bzw. 14 mm berechnet. Zusätzlich wurden aussagekräftige Informationen zum Pflanzenhöhenprofil mit einem durchschnittlichen Gesamtfehler von 8,7 mm bereitgestellt. Da die untersuchten Maispflanzen in der Höhe sehr heterogen waren, hatten einige von ihnen gefaltete Blätter und wurden mit Standardabweichungen gepflanzt, die die tatsächliche Genauigkeit einer Sämaschine nachahmen. Man kann sagen, dass der experimentelle Versuch ein schwieriges Szenario war. Daher könnte für ein Maisfeld unter besseren Bedingungen eine besseres Resultat sowohl für die Pflanzenstammposition als auch für die Höhenschätzung erwartet werden. Schließlich bedeutet eine 3D-Rekonstruktion der Maispflanzen mit einem kostengünstigen Sensor, der auf einer kleinen elektrischen, motorbetriebenen Roboterplattform montiert ist, dass die Kosten (entweder wirtschaftlich, energetisch oder zeitlich) für die Erzeugung jedes Punktes in den Punktwolken im Vergleich zu früheren Untersuchungen stark reduziert werden

Recensión del libro: "Crítica marxista del derecho. Materiales para una introducción" : Raymundo Espinoza, Itaca, México, 2018

El libro que se va a comentar reúne un conjunto de materiales para iniciarse en la crítica marxista del derecho, en éste se intenta elaborar un mapa bibliográfico sobre la relación entre el derecho y el marxismo, y cuyo objetivo es contribuir a la construcción de una teoría materialista, dialéctica e histórica de lo socialmente exigible (Espinoza 2018: 30).Facultad de Ciencias Jurídicas y Sociale

Aspectos particulares de la maduración gonádica y talla de primera madurez de Atrina maura (Bivalvia: Pinnidae)

The gonadal maturation of Atrina maura was examined by means of histological analysis and quantitative criteria. Particular features not previously described for this species are reported in this study: in both males and females the undifferentiated stage is absent and there is massive gamete resorption when the seawater temperature reaches 25°C; in males, there is continuous spawning concurrent with other gonadal development stages and the adipogranular cells surrounding the acini walls decrease with testis ripeness, which suggests they play an energetic role. Atresia displayed two stages: cytoplasmic structures with oocyte degeneration and digestion by hemocytes. The oocyte diameter was larger than that reported for cultured specimens. Size at first maturity was reached at 23.3 cm in shell height (SH) (12.2 cm in shell length, SL) in females and 22.8 cm SH (12.0 cm SL) in males.Se analizó histológicamente y usando criterios cuantitativos el proceso de maduración gonádica de Atrina maura. Se reportan características particulares que no han sido descritas previamente para la especie: ausencia de la fase de indiferenciación y reabsorción masiva de gametos, tanto en hembras como en machos, cuando la temperatura del agua alcanza los 25°C; en los machos presencia de eyaculación continua simultánea con otras fases de desarrollo gonádico y células adipogranulares arregladas alrededor de las paredes de los acinos que disminuyen conforme avanza la maduración, sugiriendo un papel energético. La atresia presentó dos fases: estructuras citoplasmáticas con degeneración ovocitaria y digestión por hemocitos. El diámetro de los ovocitos fue mayor que los reportados para organismos de cultivo. La talla de primera madurez para las hembras se estableció en 23.3 cm de altura de la concha (AC) (12.2 cm de longitud de la concha, LC) y para los machos en 22.8 cm de AC (12.0 cm de LC)

Functional expression and intracellular signaling of UTP-sensitive P2Y receptors in theca-interstitial cells

<p>Abstract</p> <p>Background</p> <p>Purinergic receptors are expressed in the ovary of different species; their physiological roles remain to be elucidated. UTP-sensitive P2Y receptor activity may regulate cell proliferation. The aim of the present work was to study the functional expression of these receptors in theca/interstitial cells (TIC).</p> <p>Methods</p> <p>TIC were isolated by centrifugation in a Percoll gradient. P2Y receptors and cellular markers in TIC were detected by RT-PCR and Western blot. Intracellular calcium mobilization induced by purinergic drugs was evaluated by fluorescence microscopy, phosphorylation of MAPK p44/p42 and of cAMP response element binding protein (CREB) was determined by Western blot and proliferation was quantified by [3H]-thymidine incorporation into DNA.</p> <p>Results</p> <p>RT-PCR showed expression of p2y2r and p2y6r transcripts, expression of the corresponding proteins was confirmed. UTP and UDP, agonists for P2Y2 and P2Y6 receptors, induced an intracellular calcium increase with a maximum of more than 400% and 200% of basal level, respectively. The response elicited by UTP had an EC50 of 3.5 +/- 1.01 μM, while that for UDP was 3.24 +/- 0.82 μM. To explore components of the pathway activated by these receptors, we evaluated the phosphorylation induced by UTP or UDP of MAPK p44 and p42. It was found that UTP increased MAPK phosphorylation by up to 550% with an EC50 of 3.34 +/- 0.92 and 1.41 +/- 0.67 μM, for p44 and p42, respectively; these increases were blocked by suramin. UDP also induced p44/p42 phosphorylation, but at high concentrations. Phosphorylation of p44/p42 was dependent on PKC and intracellular calcium. To explore possible roles of this pathway in cell physiology, cell proliferation and hCG-induced CREB-phosphorylation assays were performed; results showed that agonists increased cell proliferation and prevented CREB-phosphorylation.</p> <p>Conclusion</p> <p>Here, it is shown that UTP-sensitive P2Y receptors are expressed in cultured TIC and that these receptors had the ability to activate mitogenic signaling pathways and to promote cell proliferation, as well as to prevent CREB-phosphorylation by hCG. Regulation of TIC proliferation and steroidogenesis is relevant in ovarian pathophysiology since theca hyperplasia is involved in polycystic ovarian syndrome. Purinergic receptors described might represent an important new set of molecular therapeutic targets.</p

Crop row detection in maize for developing navigation algorithms under changing plant growth stages

To develop robust algorithms for agricultural navigation, different growth stages of the plants have to be considered. For fast validation and repeatable testing of algorithms, a dataset was recorded by a 4 wheeled robot, equipped with a frame of different sensors and was guided through maize rows. The robot position was simultaneously tracked by a total station, to get precise reference of the sensor data. The plant position and parameters were measured for comparing the sensor values. A horizontal laser scanner and corresponding total station data was recorded for 7 times over a period of 6 weeks. It was used to check the performance of a common RANSAC row algorithm. Results showed the best heading detection at a mean growth height of 0.268 m

Using Assembled 2D LiDAR Data for Single Plant Detection

A 2D laser scanner was mounted on the front of the small 4-wheel autonomous robot with differential steering, in an angle of 30 degrees pointing downwards. The machine was able to drive between maize rows and collect timestamped data simultaneously. The position of the vehicle was tracked by a highly precise total station. The data of the total station and the laser scanner was fused to generate a 3D point cloud. This 3D representation was used to search for single plant positions, what could later be used for additional applications like single plant treatment and precision weeding. First all points belonging to the ground plane were removed. Afterwards outliers were filtered. For separating the resulting points, a k-d tree clustering was used. Of each single point cloud cluster the 3D centroid was evaluated and assumed as the resulting plant position. This was done on three different growth stages of the plants. Results showed good detection rates up to 70.7 % with a root mean square error of 3.6 cm, precise enough to allow single plant treatment

Las mujeres son más peligrosas mediante la palabra: el chisme entre estudiantes de la Universidad Autónoma Chapingo, en México.

This article describes gossip perceptions in young students at thesecond year of the high school in the Autonomous University ofChapingo (UACh) in México. The analysis centers around threesubject areas related to gossip: its association with women, itssocial function, and alternatives in face of its impact on daily life.The results are: first, although prevails the stereotype of gossipywomen, there is a recognition that men also gossip, albeit in amore discrete manner; second, the social function of gossip at theUACh can be of three kinds: the one that strengthens bonds;thatwhich promotes personal interests; or the one that serves bothpurposes, depending on the context where it is spread and itscontent; third, men and women agree that gossip has a negativeimpact on people’s lives, but women declare having been victimsin larger percentages. Some of them consider that gossip isinevitable, while others foresee two alternatives to diminish itsharm: educating people; the personal option of ignoring it, bychanging behavior to avoid being its victim or confronting theperson who spreads it.En este trabajo se describen las percepciones del chisme de jóvenesde segundo año de la Preparatoria Agrícola de la UniversidadAutónoma Chapingo (UACh) en México. El análisis se centraen tres temáticas relativas al chisme: su asociación con lasmujeres, su función social, y las alternativas frente a su impactoen la vida cotidiana. Los resultados son: primero, aunque predominael estereotipo de la mujer chismosa, también se reconoceque los varones chismean aunque de manera más discreta; segundo,la función social del chisme en la UACh puede ser de trestipos: el que estrecha lazos; el que promueve intereses personales;o el que sirve para ambas cosas, dependiendo del contexto enel que se esparce y de su contenido; tercero, hombres y mujerescoinciden en que el chisme tiene un impacto negativo en la vidade las personas, pero las mujeres declaran haber sido víctimas enporcentajes mayores. Algunas consideran que el chisme es inevitable,mientras que otras vislumbran dos alternativas para disminuirsu daño: la educación de la gente; y la opción personal deignorarlo, cambiar de comportamiento para no ser su víctima oconfrontar a la persona que lo disemina

3D Maize Plant Reconstruction Based on Georeferenced Overlapping LiDAR Point Clouds

3D crop reconstruction with a high temporal resolution and by the use of non-destructive measuring technologies can support the automation of plant phenotyping processes. Thereby, the availability of such 3D data can give valuable information about the plant development and the interaction of the plant genotype with the environment. This article presents a new methodology for georeferenced 3D reconstruction of maize plant structure. For this purpose a total station, an IMU, and several 2D LiDARs with different orientations were mounted on an autonomous vehicle. By the multistep methodology presented, based on the application of the ICP algorithm for point cloud fusion, it was possible to perform the georeferenced point clouds overlapping. The overlapping point cloud algorithm showed that the aerial points (corresponding mainly to plant parts) were reduced to 1.5%–9% of the total registered data. The remaining were redundant or ground points. Through the inclusion of different LiDAR point of views of the scene, a more realistic representation of the surrounding is obtained by the incorporation of new useful information but also of noise. The use of georeferenced 3D maize plant reconstruction at different growth stages, combined with the total station accuracy could be highly useful when performing precision agriculture at the crop plant level