Disease-induced resource constraints can trigger explosive epidemics

Advances in mathematical epidemiology have led to a better understanding of the risks posed by epidemic spreading and informed strategies to contain disease spread. However, a challenge that has been overlooked is that, as a disease becomes more prevalent, it can limit the availability of the capital needed to effectively treat those who have fallen ill. Here we use a simple mathematical model to gain insight into the dynamics of an epidemic when the recovery of sick individuals depends on the availability of healing resources that are generated by the healthy population. We find that epidemics spiral out of control into "explosive" spread if the cost of recovery is above a critical cost. This can occur even when the disease would die out without the resource constraint. The onset of explosive epidemics is very sudden, exhibiting a discontinuous transition under very general assumptions. We find analytical expressions for the critical cost and the size of the explosive jump in infection levels in terms of the parameters that characterize the spreading process. Our model and results apply beyond epidemics to contagion dynamics that self-induce constraints on recovery, thereby amplifying the spreading process.Comment: 24 pages, 6 figure

Strong, lightweight, and recoverable three-dimensional ceramic nanolattices

Ceramics have some of the highest strength- and stiffness-to-weight ratios of any material but are suboptimal for use as structural materials because of their brittleness and sensitivity to flaws. We demonstrate the creation of structural metamaterials composed of nanoscale ceramics that are simultaneously ultralight, strong, and energy-absorbing and can recover their original shape after compressions in excess of 50% strain. Hollow-tube alumina nanolattices were fabricated using two-photon lithography, atomic layer deposition, and oxygen plasma etching. Structures were made with wall thicknesses of 5 to 60 nanometers and densities of 6.3 to 258 kilograms per cubic meter. Compression experiments revealed that optimizing the wall thickness-to-radius ratio of the tubes can suppress brittle fracture in the constituent solid in favor of elastic shell buckling, resulting in ductile-like deformation and recoverability

Evaluación de factibilidad en proyecto de remodelación DFL2 en la comuna de Providencia

Tesis (Ingeniero Constructor)El objetivo de la empresa que se desea formar para entrar a competir en el mercado de compra, venta y remodelación de casas DFL2 es mantener la historia de los barrios más homogéneos de Santiago tales como Ñuñoa, Providencia, Vitacura, Las Condes, o sectores como Parque forestal y Barrios Lastarrias, en cuanto a lo tangible, ya que, como empresa constructora e inmobiliaria lo que se busca siempre es mantener el aspecto de la vivienda, la fachada exterior de un Santiago tradicional, realizando solo remodelaciones interiores; con el propósito de abaratar costos aprovecharemos la calidad de construcciones que mantienen las casas antiguas, en cuanto a sus terminaciones y obra gruesa. La finalidad es proponer a los posibles usuarios ampliar el espacio del hogar, entregándoles confort y opciones a una mejor calidad de vida. Este proyecto de compra, venta y remodelación de propiedades lleva consigo diferentes tipos de estudios previos para la ejecución final o aprobación de éste, en cuanto ver si efectivamente es viable realizar esta idea. Los estudios de pre-factibilidad como el análisis de mercado, costos asociados, análisis FODA entre otros, serán de suma importancia para nuestra posterior aprobación del proyecto. Sin embargo, hay que tener en cuenta una correcta adaptación a los diferentes ambientes, es decir, saber qué es lo que se debe mantener y lo que se debe rehacer o crear, para así aumentar su nivel de plusvalía generando mayores ingresos por proyecto, sea abaratando costos, minimizando pérdidas, rapidez y exactitud en la ejecución y buscar los mejores métodos para implementar las soluciones adecuadas en cuanto a problemas presentados como empresa dentro del rubro de compra, venta y remodelación de propiedades. Para obtener resultados óptimos es muy importante ser minuciosos y acertados en la búsqueda y recopilación de datos, en cada una de las tareas asociadas a la remodelación y entrega final de la vivienda. Nuestros parámetros establecidos en las remodelaciones, se encuentran en los más altos estándares, para así lograr prestigio asociado a nuestro trabajo, todo esto en conjunto con la calidad y estándares de diseños vanguardistas, con la finalidad de apuntar a un público o perfil especifico, que solicite servicios particulares que mejoren su calidad de vida

Rethinking Ductility -- A Study Into the Size-Affected Fracture of Polymers

Ductility quantifies a material's capacity for plastic deformation, and it is a key property for preventing fracture driven failure in engineering parts. While some brittle materials exhibit improved ductility at small scales, the processes underlying this phenomenon are not well understood. This work establishes a mechanism for the origin of ductility via an investigation of size-affected fracture processes and polymer degree of conversion (DC) in two-photon lithography (TPL) fabricated materials. Microscale single edge notch bend ($\mu$SENB) specimens were written with widths from 8 to 26 $\mu$m and with different laser powers and post-write thermal annealing to control the DC between 17\% and 80\%. We find that shifting from low to high DC predictably causes a $\sim$3x and $\sim$4x increase in strength and bending stiffness, respectively, but that there is a corresponding $\sim$6x decrease in fracture energy from 180 $J/m^2$ to 30 $J/m^2$. Notably, this reduced fracture energy is accompanied by a ductile-to-brittle transition (DBT) in the failure behavior. Using finite element analysis, we demonstrate that the DBT occurs when the fracture yielding zone size ($r_p$) approaches the sample width, corresponding with a known fracture size-affected transition from flaw-based to strength-based failure. This finding provides a crucial insight that ductility is a size-induced property that occurs when features are reduced below a characteristic fracture length scale and that strength, stiffness, and toughness alone are insufficient predictors of ductility.Comment: 17 pages, 6 figure

FACTORES JURÍDICOS QUE CONDICIONAN LA REINCIDENCIA EN HOGARES DE MANABÍ CON HECHOS DE VIOLENCIA INTRAFAMILIAR

convertido en un fenómeno analizado a lo largo de la historia de nuestro país por todos los sucesos ocurridos que marcan la cronología de la vida de una mujer y por qué no decir en todo el mundo por los evidentes impactos que deja esta problemática en la sociedad en torno a brutales y malintencionadas expresiones de conductas violentas en contra de género femenino, que atentan contra los derechos humanos y los de toda una familia indistintamente de su condición socioeconómica, religión, cultura u otra consideración. Si bien la familia debe proteger a sus integrantes, pero si uno de estos integrantes como es la madre, o la mujer a quien cuyo cargo se encuentre esta familia presenta inconvenientes en este sistema integral, obviamente va a afectar ese equilibrio del grupo como tal, producto de conflictos que en algún momento no se resolvieron pertinentemente, lo que conlleva al acometimiento de violencia intrafamiliar a través de actos físicos, psicológicos y sexuales, que perjudicando al núcleo. Es importante analizar las afectaciones en integrantes de la familia con problemas de violencia intrafamiliar, sus consecuencias psicológicas, sociales y jurídicas después de una sentencia. No obstante, aunque contamos con los mecanismos de acción, legislación especializada, instituciones protectoras de derechos; se puede identificar que existen falencias desde las resoluciones administrativas y sentencias judiciales. Se vulneran aun los derechos de la familia, de la mujer víctima, quien se revictimiza en todos los ámbitos.PALABRAS CLAVE: Violencia intrafamiliar; afectaciones psicosociales; revictimización; impunidad.LEGAL FACTORS THAT CONDITION THE REINCIDENCE IN MANABÍ HOMES WITH FACTS OF VIOLENCE INTRAFAMILIARABSTRACTThe facts of intrafamily violence, especially those that are exercised against women, has become a phenomenon analyzed throughout the history of our country by all the events that mark the chronology of a woman's life and why not to say all over the world because of the obvious impacts that this problem leaves on society around brutal and malicious expressions of violent behavior against women, which threaten the human rights and those of a whole family regardless of their socio- economic, religion, culture or other consideration. Although the family must protect its members, but if one of these members, such as the mother, or the woman whose position this family finds, has problems in this integral system, it will obviously affect that balance of the group as such, product of conflicts that at some time were not resolved properly, which leads to the attack of intrafamiliar violence through physical, psychological and sexual acts, which harms the core. It is important to analyze the effects on members of the family with problems of intrafamily violence, its psychological, social and legal consequences after a sentence. However, although we have mechanisms of action, specialized legislation, institutions that protect rights; it can be identified that there are flaws from the administrative resolutions and court decisions. The rights of the family, of the victim woman, who is revictimized in all areas, are still violated.KEYWORDS: Intrafamily violence; psychosocial affectations; revictimization; impunity

Cryogenic nanoindentation size effect in [0 0 1]-oriented face-centered cubic and body centered cubic single crystals

Cryogenic nanoindentation experiments performed on [0 0 1]-oriented single crystalline Nb, W, Al, and Au in an in situ nanomechanical instrument with customized cryogenic testing capability revealed temperature dependence on nanoindentation size effect. The Nix-Gao model, commonly used to capture indentation size effect at room temperature, does not take into account thermal effects and hence is not able to explain these experimental results where both hardness at infinite indentation depth and characteristic material length scale were found to be strong functions of temperature. Physical attributes are critically examined in the framework of intrinsic lattice resistance and dislocation cross-slip probability

Ballast Treated with Asphalt Emulsion, Megarok and San Jose. AASTHO Standards

In the research work, the results obtained at the laboratory level of the lending material (ballast) treated with asphalt emulsion from the quarries "Megarok and San José" are compared, applying the AASTHO standards. The quarries are located in the Picoazá-La Sequita parish of the Portoviejo canton. Samples from both quarries were evaluated in the laboratory and it was possible to carry out tests of natural humidity, Atterberg, granulometric, compaction, and soil bearing capacity (CBR). Based on the results obtained, they were compared by disclosing which of the quarries meets the appropriate conditions within the construction standards and techniques, in order to stabilize the material with asphalt emulsion; in addition to comparing it with the specifications of the AASTHO standards and the MTOP standard. The result was that the materials extracted from the quarries do not meet the technical specifications; but when mixed with the asphalt emulsion, the Megarok material fulfills as type A base

Gestión educativa como factor determinante del desempeño de docentes de educación básica regular durante la pandemia Covid-19, Puno-Perú

The objective of this research was to analyze the effect of educational management on the teaching performance of teachers of Basic Basic Education in the department of Puno, during the COVID-19 Pandemic. It corresponds to an investigation with a quantitative approach, explanatory scope and non-experimental design, which included the participation of 650 teachers from 10 Units of Local Educational Management, to whom a scale of perception of educational management and a self-assessment questionnaire of the teaching performance, both valid and reliable; The analyzes were performed based on a significance level of 5% and a confidence level of 95%. The results show a direct and significant correlation between the variable educational management and teacher performance (r = .623, p <.05), in the same way with the institutional management dimensions (r = .523, p <.05), Pedagogical management (r = .499, p <0.05), Administrative management (r = .611, p <.05) and Community management (r = .514, p <.05). In addition to this, the multiple linear regression model explains the effect that the educational management variable and its dimensions have on the teaching performance of teachers in Puno. It is concluded that educational management, which can be understood as the strengthening of Educational Projects and the enrichment of pedagogical processes in order to respond to local and regional educational needs, is a determining factor that explains the level of performance they achieve teachers of Regular Basic Education in Puno during the COVID-19 Pandemic.La presente investigación tuvo como objetivo analizar el efecto de la gestión educativa sobre el desempeño docente en profesores de Educación Básica Regular del departamento de Puno, durante la Pandemia COVID-19. Corresponde a una investigación de enfoque cuantitativo, alcance explicativo y diseño no experimental, que contó con la participación de 650 docentes de 10 Unidades de Gestión Educativa Local, a quienes se les aplicó una escala de percepción de la gestión educativa y un cuestionario de autoevaluación del desempeño docente, ambos válidos y confiables; los análisis se realizaron en base a un nivel de significancia del 5% y nivel de confianza del 95%. Los resultados dan cuenta de una correlación directa y significativa entre la variable gestión educativa y desempeño docente (r = .623, p < .05), de igual forma con las dimensiones gestión institucional (r =.523, p < .05), Gestión pedagógica (r =.499, p < 0.05), Gestión administrativa (r =.611, p < .05) y Gestión comunitaria (r = .514, p < .05). Aunado a esto, el modelo de regresión lineal múltiple explica el efecto que tiene la variable gestión educativa y sus dimensiones, sobre el desempeño docente en los profesores de Puno. Se concluye que la gestión educativa, que puede ser entendida como el fortalecimiento de los Proyectos Educativos y el enriquecimiento de los procesos pedagógicos con el fin de responder a las necesidades educativas locales y regionales, es un factor determinante que explica el nivel de desempeño que logran los profesores de Educación Básica Regular de Puno durante la Pandemia COVID-19