The role of hydrogeology to achieve the water security

[Abstract] The concept of water security focuses on the objective of water management in society. However, in urban environments -where requirements related to water supply, floods, important rains, rising water tables, pollution problems, among others-, the lack of data and information appropriate to the scale of work, and even the inappropriate use of methodologies, attempt against any attempt to improve this capacity of the population to deal with critical situations. Even in the cities, it is more evident that the challenge of achieving a balance between the supply of water -finite, vulnerable and variable-, and an offer - tirelessly growing, of multiple users and interdependent-, forces us to “rethink” the hydrological cycle as a dynamic environmental system and with it, to add an interdisciplinary approach to hydrology. This paper presents the methodologies, results and conclusions that have served as the basis for improving knowledge of aquifer systems in the cities of Esperanza and Santa Fe (Argentina). The first supports its supply with groundwater, which is essential to protect the resource and the collection works. In the second case, the interrelation between surface and underground water is complex and requires that hydrodynamics of the system as a whole should be considered to define the best technological alternatives for urban infrastructure and the management of floods. The advances achieved point to the importance of science, as an engine that generates effective solutions for society to achieve the goals of sustainable development and water security.[Resumen] El concepto de seguridad hídrica focaliza el objetivo de la gestión del agua en la sociedad. Sin embargo, en los ambientes urbanos -donde deben atenderse requerimientos relacionados al abastecimiento de agua, inundaciones, lluvias intensas, ascenso del nivel freático, problemas de contaminación, entre otros-, la falta de datos e información adecuadas a la escala de trabajo, e incluso el uso inapropiado de metodologías, atentan contra cualquier intento de mejorar esta capacidad de la población para hacer frente a las situaciones críticas. Incluso en las ciudades es más evidente que el desafío de lograr el equilibrio entre la oferta de agua –finita, vulnerable y variable-, y una oferta -incansablemente creciente, de múltiples usuarios e interdependiente-, obliga a “re pensar” el ciclo hidrológico como un sistema ambiental dinámico y con ello, a sumar a la Hidrología un enfoque interdisciplinar. En este trabajo se presentan las metodologías, resultados y conclusiones que han servido de base para mejorar el conocimiento de los sistemas acuíferos de las ciudades de Esperanza y Santa Fe (Argentina). La primera sustenta su abastecimiento con aguas subterráneas, con lo cual es indispensable la protección del recurso y las obras de captación. En el segundo caso, la interrelación entre el agua superficial y la subterránea es compleja y requiere que hidrodinámica del sistema en su conjunto deba ser considerada para definir las mejores alternativas tecnológicas de la infraestructura urbana y el manejo de las inundaciones. Los avances logrados señalan la importancia de la ciencia, como motor que genera soluciones efectivas para que la sociedad alcance las metas del desarrollo sostenible y la seguridad hídric

Catálogo taxonómico-geográfico de los coleópteros de la familia Meloidae de México

A comprehensive taxonomic catalogue of the Mexican representatives of the family Meloidae is presented. The catalogue includes a revised synonymical list including type localities and published geographical records for all known species. The Mexican Fauna of Meloidae currently includes 255 extant species, plus one only known from the fossil record, arranged in 21 genera within the subfamilies Meloinae, Nemognathinae and Tetraonycinae. The last comprehensive catalogue published (Blackwelder, 1945) recorded the presence of 160 species of Meloidae in México, almost 100 species less than the current known number. However the current number of species seems to be far below the actual number, since many species widely distributed along the northern border, within the United States, are likely to be found also in Mexico. Regarding taxonomic and nomenclatural changes, in this catalogue we propose the use of the names Epicauta dugesi Werner, 1957 and Tegrodera erosa extincta Beauregard, 1890; we propose three new synonymies for Nemognatha chrysomeloides (Linnaeus, 1763) (N. atra Beauregard, 1890; N. pallidicollis Beauregard, 1890 and N. violacea Beauregard, 1890) and one for E. dugesi (Epicauta tamara Adams & Selander, 1979); we designate lectotype for Lytta koltzei var. minor Haag-Rutenberg, 1880 with the goal of resolving the taxonomic problem generated by the previous invalid designation of lectotype for L. k. var. cyanescens; and finally we consider Cissites maculata (Swederus, 1787) and Tetraonyx (Tetraonyx) bimaculatus (Klug, 1825) as species to be possibly excluded from the Mexican checklist.Se presenta un catálogo taxonómico de los representantes mexicanos de la familia Meloidae que incluye un listado revisado de sinonimias, localidades típicas y registros geográficos publicados de cada una de las especies. La fauna mexicana incluye en la actualidad 255 especies vivientes y una fósil, distribuidas en 21 géneros de las subfamilias Meloinae, Nemognathinae y Tetraonycinae. En el último catálogo general, Blackwelder (1945) recogió la presencia en México de 160 especies de esta familia, casi 100 especies menos de las que se conocen en la actualidad y sin embargo, la cifra actual parece encontrarse aún lejos de la real, ya que existen muchas especies ampliamente distribuidas al norte de la frontera con los Estados Unidos cuya presencia es muy probable en territorio mexicano. En cuanto a la taxonomía y nomenclatura de las especies, en este catálogo se propone el uso de los nombres Epicauta dugesi Werner, 1957 y Tegrodera erosa extincta Beauregard, 1890; se incluyen tres sinonimias nuevas de Nemognatha chrysomeloides (Linnaeus, 1763) (N. atra Beauregard, 1890; N. pallidicollis Beauregard, 1890 y N. violacea Beauregard, 1890) y otra de E. dugesi (Epicauta tamara Adams & Selander, 1979); se designa lectotipo para Lytta koltzei var. minor Haag-Rutenberg, 1880 con el propósito de solucionar el problema taxonómico generado tras la designación inválida de lectotipo de L. k. var. cyanescens; y finalmente se consideran como especies posiblemente a excluir del listado de Meloidae de México a Cissites maculata (Swederus, 1787) y Tetraonyx (Tetraonyx) bimaculatus (Klug, 1825)

Vacuum Polarization and Energy Conditions at a Planar Frequency Dependent Dielectric to Vacuum Interface

The form of the vacuum stress-tensor for the quantized scalar field at a dielectric to vacuum interface is studied. The dielectric is modeled to have an index of refraction that varies with frequency. We find that the stress-tensor components, derived from the mode function expansion of the Wightman function, are naturally regularized by the reflection and transmission coefficients of the mode at the boundary. Additionally, the divergence of the vacuum energy associated with a perfectly reflecting mirror is found to disappear for the dielectric mirror at the expense of introducing a new energy density near the surface which has the opposite sign. Thus the weak energy condition is always violated in some region of the spacetime. For the dielectric mirror, the mean vacuum energy density per unit plate area in a constant time hypersurface is always found to be positive (or zero) and the averaged weak energy condition is proven to hold for all observers with non-zero velocity along the normal direction to the boundary. Both results are found to be generic features of the vacuum stress-tensor and not necessarily dependent of the frequency dependence of the dielectric.Comment: 16 pages, 4 figures, Revtex style Minor typographic corrections to equations and tex

Tolman wormholes violate the strong energy condition

For an arbitrary Tolman wormhole, unconstrained by symmetry, we shall define the bounce in terms of a three-dimensional edgeless achronal spacelike hypersurface of minimal volume. (Zero trace for the extrinsic curvature plus a "flare-out" condition.) This enables us to severely constrain the geometry of spacetime at and near the bounce and to derive general theorems regarding violations of the energy conditions--theorems that do not involve geodesic averaging but nevertheless apply to situations much more general than the highly symmetric FRW-based subclass of Tolman wormholes. [For example: even under the mildest of hypotheses, the strong energy condition (SEC) must be violated.] Alternatively, one can dispense with the minimal volume condition and define a generic bounce entirely in terms of the motion of test particles (future-pointing timelike geodesics), by looking at the expansion of their timelike geodesic congruences. One re-confirms that the SEC must be violated at or near the bounce. In contrast, it is easy to arrange for all the other standard energy conditions to be satisfied.Comment: 8 pages, ReV-TeX 3.

Tumor growth instability and the onset of invasion

Motivated by experimental observations, we develop a mathematical model of chemotactically directed tumor growth. We present an analytical study of the model as well as a numerical one. The mathematical analysis shows that: (i) tumor cell proliferation by itself cannot generate the invasive branching behaviour observed experimentally, (ii) heterotype chemotaxis provides an instability mechanism that leads to the onset of tumor invasion and (iii) homotype chemotaxis does not provide such an instability mechanism but enhances the mean speed of the tumor surface. The numerical results not only support the assumptions needed to perform the mathematical analysis but they also provide evidence of (i), (ii) and (iii). Finally, both the analytical study and the numerical work agree with the experimental phenomena.Comment: 12 pages, 8 figures, revtex

Heat kernel regularization of the effective action for stochastic reaction-diffusion equations

The presence of fluctuations and non-linear interactions can lead to scale dependence in the parameters appearing in stochastic differential equations. Stochastic dynamics can be formulated in terms of functional integrals. In this paper we apply the heat kernel method to study the short distance renormalizability of a stochastic (polynomial) reaction-diffusion equation with real additive noise. We calculate the one-loop {\emph{effective action}} and its ultraviolet scale dependent divergences. We show that for white noise a polynomial reaction-diffusion equation is one-loop {\emph{finite}} in $d=0$ and $d=1$, and is one-loop renormalizable in $d=2$ and $d=3$ space dimensions. We obtain the one-loop renormalization group equations and find they run with scale only in $d=2$.Comment: 21 pages, uses ReV-TeX 3.

Identity of the van der Waals Force and the Casimir Effect and the Irrelevance of these Phenomena to Sonoluminescence

We show that the Casimir, or zero-point, energy of a dilute dielectric ball, or of a spherical bubble in a dielectric medium, coincides with the sum of the van der Waals energies between the molecules that make up the medium. That energy, which is finite and repulsive when self-energy and surface effects are removed, may be unambiguously calculated by either dimensional continuation or by zeta function regularization. This physical interpretation of the Casimir energy seems unambiguous evidence that the bulk self-energy cannot be relevant to sonoluminescence.Comment: 7 pages, no figures, REVTe

Sonoluminescence as a QED vacuum effect. II: Finite Volume Effects

In a companion paper [quant-ph/9904013] we have investigated several variations of Schwinger's proposed mechanism for sonoluminescence. We demonstrated that any realistic version of Schwinger's mechanism must depend on extremely rapid (femtosecond) changes in refractive index, and discussed ways in which this might be physically plausible. To keep that discussion tractable, the technical computations in that paper were limited to the case of a homogeneous dielectric medium. In this paper we investigate the additional complications introduced by finite-volume effects. The basic physical scenario remains the same, but we now deal with finite spherical bubbles, and so must decompose the electromagnetic field into Spherical Harmonics and Bessel functions. We demonstrate how to set up the formalism for calculating Bogolubov coefficients in the sudden approximation, and show that we qualitatively retain the results previously obtained using the homogeneous-dielectric (infinite volume) approximation.Comment: 23 pages, LaTeX 209, ReV-TeX 3.2, five figure

Niveles de vitamina D en pacientes recién diagnosticados de cáncer

Introducción: aparte de los conocidos efectos de la vitamina D sobre la homeostasis fosfo-cálcica, en los últimos años están cobrando gran relevancia sus efectos extraóseos. Objetivos: conocer la concentración de 25(OH) vitamina D en pacientes recién diagnosticados de cáncer y comprobar si existen diferencias entre los distintos tipos de cáncer. Material y métodos: estudio transversal de una cohorte de pacientes recién diagnosticados de cáncer que fueron remitidos a Consultas Externas de Endocrinología para una valoración nutricional preoperatoria. Se revisaron 139 historias clínicas y se obtuvieron los datos sociodemográficos, biométricos y la concentración de 25(OH) vitamina D de los pacientes. Resultados: de los 139 pacientes, 71 padecían cáncer urológico; 27, cáncer colorrectal (CCR); 35, cáncer de cabeza y cuello (C y C); y seis, cáncer de otro tipo. La concentración media de 25(OH) vitamina D fue de 50, 41 nmol/l (IC 95% = 46, 68-54, 14). El 57, 97% presentó déficit de vitamina D (< 50 nmol/l) y un 21, 74%, insuficiencia (50-75 nmol/l). Hallamos una mayor prevalencia de déficit estadísticamente significativa (p < 0, 01) en el C y C frente al cáncer urológico: 68, 57% y 49, 29% respectivamente. La estación del año modifica de manera significativa la concentración de 25(OH) vitamina D (p < 0, 01). Conclusiones: hay una alta prevalencia de déficit de vitamina D en los pacientes recién diagnosticados de cáncer (sobre todo en CCR y C y C); por ello, se debe priorizar la corrección de los niveles de 25(OH) vitamina D en estos pacientes. La utilización de valores de referencia ajustados según la estación del año podría mejorar la interpretación de resultados. Introduction: apart from the known effects of vitamin D on phospho-calcium homeostasis, in recent years there is great interest in its extra-bone effects. Objectives: to know the concentration of 25-hydroxyvitamin D (25[OH] D) in newly diagnosed patients of cancer and to verify if there are differences between the different types of cancer. Material and methods: cross-sectional study of a cohort of recent diagnosed cancer patients who were referred to Endocrinology consultation for a nutritional pre-surgery evaluation. One hundred and thirty-nine medical histories were reviewed. The socio-demographic and biometric data and 25(OH) D concentration were collected. Results: seventy-one of 139 patients had urological cancer, 27 had colorectal cancer (CRC), 35 had head and neck cancer and six, other types of cancer. The mean concentration of 25(OH) D was 50.41 nmol/l (95% CI = 46.67-54.14); 57.97% of patients showed vitamin D deficiency (< 50 nmol/l) and 21.74%, insufficiency (50-75 nmol/l). We found a statistically significant higher prevalence of deficiency (p < 0.01) in head and neck cancer compared to urological cancer: 68.57% and 49.29%, respectively. Year season significantly modifies 25(OH) D concentration (p < 0.01). Conclusions: there is a high prevalence of vitamin D deficiency among recent diagnosed cancer patients (especially in CRC and head and neck cancer). The use of reference values adjusted by year season could improve the study of 25(OH) D concentrations

Study of the preheating phase of chaotic inflation

Particle production and its effects on the inflaton field are investigated during the preheating phase of chaotic inflation using a model consisting of a massive scalar inflaton field coupled to N massless quantum scalar fields. The effects of spacetime curvature and interactions between the quantum fields are ignored. A large N expansion is used to obtain a coupled set of equations including a backreaction equation for the classical inflaton field. Previous studies of preheating using these equations have been done. Here the first numerical solutions to the full set of equations are obtained for various values of the coupling constant and the initial amplitude of the inflaton field. States are chosen so that initially the backreaction effects on the inflaton field are small and the mode equations for the quantum fields take the form of Mathieu equations. Potential problems relating to the parametric amplification of certain modes of the quantum fields are identified and resolved. A detailed study of the damping of the inflaton field is undertaken. Some predictions of previous studies are verified and some new results are obtained.Comment: PRD version, some changes and corrections, 37 pages, 10 figure