A one-sided Prime Ideal Principle for noncommutative rings

Completely prime right ideals are introduced as a one-sided generalization of the concept of a prime ideal in a commutative ring. Some of their basic properties are investigated, pointing out both similarities and differences between these right ideals and their commutative counterparts. We prove the Completely Prime Ideal Principle, a theorem stating that right ideals that are maximal in a specific sense must be completely prime. We offer a number of applications of the Completely Prime Ideal Principle arising from many diverse concepts in rings and modules. These applications show how completely prime right ideals control the one-sided structure of a ring, and they recover earlier theorems stating that certain noncommutative rings are domains (namely, proper right PCI rings and rings with the right restricted minimum condition that are not right artinian). In order to provide a deeper understanding of the set of completely prime right ideals in a general ring, we study the special subset of comonoform right ideals.Comment: 38 page

Agrupaciones de modelos locales con descripción externa. Aplicación a una planta de frío solar

En este artículo se presenta y analiza un método de creación de modelos formados por agrupaciones de submodelos locales lineales. La principal novedad es que la ponderación empleada con los submodelos no es la habitual, basada en el estado o parte del mismo sino que se toman exclusivamente señales instantáneas de entrada y salida del sistema. Esta elección simplifica algunos aspectos de la creación del modelo, manteniendo intacta la capacidad de representación, siendo ´esta comparada con otras técnicas. La simplificación aludida es importante pues acerca el método a la práctica industrial del control de procesos. La técnica de identificación resultante se ilustra mediante dos casos prácticos: un sistema simulado propuesto por Narendra y el sistema de captación de una planta real de producción de frío a partir de energía solar. En ambos casos se muestran los errores de generalización para la predicción a un paso y para la simulación usando gran cantidad de situaciones. Los resultados indican que es factible el uso del método propuesto como técnica simplificada aplicable en la industria.Comisión de la Comunidad Europea Proyecto de investigación HYCON FP6-51136

Microsurgical Techniques in Cerebral Revascularization

The surgical management of patients with cerebrovascular disease is reviewed. Our approach to the management of extracranial cerebral vasculature is discussed first, and increasingly more complex areas are then presented. Our discussion reviews the applications of carotid endarterectomy, extracranial-intracranial bypass procedures, and vertebral extracranial reconstruction

Propiedades de los suelos en diferentes usos agropecuarios, Las Tunas, Cuba

La degradación de los pastizales, constituye uno de los problemas más graves relacionados con el uso de los suelos en la zona norte del municipio de Las Tunas, Cuba. El manejo inadecuado de los suelos, ha provocado su deterioro progresivo con impactos negativos en la producción ganadera, lo que ha incidido en la producción de carne y leche, incrementa los costos de producción y causa efectos desfavorables en el medio ambiente. En el presente trabajo se evaluó el efecto de diferentes sistemas de uso agropecuarios en algunas propiedades de los suelos Luvisoles haplicos, desarrollados sobre granitoides. Los sistemas de uso incluyen pastos naturales, pastos cultivados, sistema silvopastoril y un sistema de referencia natural. Las propiedades de suelos medidas fueron la textura, la densidad aparente, la capacidad de campo, la porosidad total y de aireación, velocidad de infiltración, el contenido de materia orgánica y la enzima β-glucosidasa. Los resultados mostraron que las tecnologías de manejo aplicadas en los pastizales afectan las propiedades de los suelos e inciden en su degradación, con incrementos en la densidad aparente, menores valores de infiltración, porosidad y menor actividad de la enzima ß-glucosidasa lo que limita el funcionamiento del sistema suelo-planta-animal. Se evidenció un efecto conservacionista de los suelos en el sistema silvopastoril, respecto a las propiedades físicas, químicas y biológicas, lo que constituye una alternativa para la recuperación de los suelos de pastizales en los sistemas ganaderos de la región

Caracterización de pacientes con compromiso pulmonar intersticial asociado a esclerosis sistémica atendidos en el Hospital Militar Central desde enero de 1998 a mayo de 2008

La esclerosis sistémica es una enfermedad clínicamente heterogénea, caracterizada por sobreproducción y depósito de tejido colágeno en piel, órganos internos y pared de vasos sanguíneos. El pronóstico depende en gran parte del compromiso de órganos internos, particularmente el pulmón, siendo éste el segundo órgano más afectado, sólo superado por el esófago. Las dos principales presentaciones clínicas de compromiso pulmonar son la enfermedad pulmonar intersticial y la hipertensión arterial pulmonar, siendo la principal causa de mortalidad en estos pacientes. El objetivo del presente estudio consiste en describir las características clínicas, epidemiológicas, de función pulmonar e imagenológicas del compromiso pulmonar intersticial en pacientes con esclerosis sistémic

Are seed mass and seedling size and shape related to altitude? Evidence in Gymnocalycium monvillei (Cactaceae)

"Several studies reported a negative relationship between altitude and seed mass. In cactus species, seed mass has been also related to seedling morphology (size and shape). Here we studied Gymnocalycium monvillei (Lem.) Pfeiff. ex Britton & Rose, a cactus species with a wide altitudinal distribution, with the main aim of analyzing how altitude affects seed mass and seedling size (height and width) and shape (globose or columnar). We collected seeds from five sites along the entire altitudinal distribution of the species in the Córdoba Mountains (sites were located between 878 and 2230 m a.s.l.), encompassing a marked climatic gradient (6 °C of mean annual temperature difference between the extreme sites). Seed mass and seedling traits were measured in the laboratory. Seedling height increased with altitude, whereas seed mass was not related to this parameter. Seedlings became more globose (reduced surface/volume ratio) with decreasing altitude. Variation in seedling shape along the altitudinal gradient may be related to the contrasting climatic conditions to which seedlings are exposed, and could account for the wide altitudinal distribution of G. monvillei. Our results highlight the importance of seedling traits in the species’ response to climatic change.

Obstructing extensions of the functor Spec to noncommutative rings

In this paper we study contravariant functors from the category of rings to the category of sets whose restriction to the full subcategory of commutative rings is isomorphic to the prime spectrum functor Spec. The main result reveals a common characteristic of these functors: every such functor assigns the empty set to M_n(C) for n >= 3. The proof relies, in part, on the Kochen-Specker Theorem of quantum mechanics. The analogous result for noncommutative extensions of the Gelfand spectrum functor for C*-algebras is also proved.Comment: 23 pages. To appear in Israel J. Math. Title was changed; introduction was rewritten; old Section 2 was removed to streamline the exposition; final section was rewritten to omit an error in the earlier proof of Theorem 1.

A Feasibility Study on Disasters and Disaster Risk Reduction Factors Awareness of LSPU Students

This study determined the students' degree of awareness at Laguna State Polytechnic University (LSPU) Sta. Cruz, Laguna in terms of disaster risk reduction and its significance, which was the basis of the LSPU DRRM Center construct. This employed a descriptive- correlational study and used a purposive sampling technique. The results revealed that the respondents had experienced various types of disasters. They are slightly aware, at least, of risk reduction factors anchoring on political commitment, while they are no less than slightly aware of the particulars related to risk reduction measures. Moreover, the results of χ² Tests of Independence revealed that the awareness of Disaster Risk Reduction Factors depends on the individual's exposure to a single or a combination of natural disasters. On the contrary, the extent of awareness of those factors does not depend on the respondent's exposure or experience with global viral diseases and man-made disasters

Taking Blockchain Seriously

In the present techno-political moment it is clear that ignoring or dismissing the hype surrounding blockchain is unwise, and certainly for regulatory authorities and governments who must keep a grip on the technology and those promoting it, in order to ensure democratic accountability and regulatory legitimacy within the blockchain ecosystem and beyond. Blockchain is telling (and showing) us something very important about the evolution of capital and neoliberal economic reason, and the likely impact in the near future on forms and patterns of work, social organization, and, crucially, on communities and individuals who lack influence over the technologies and data that increasingly shape and control their lives. In this short essay I introduce some of the problems in the regulation of blockchain and offer counter-narratives aimed at cutting through the hype fuelling the ascendency of this most contemporary of technologies

Improving the revision stage of a CBR system with belief revision techniques.

This paper presents a method for automating the revise phase of case-based reasoning systems. The revision is carried out using a rule -based system, which adapts its rules or knowledge base as the working environment, to which the system is applied, evolves in time. This actualisation is carried out by a belief revision technique. An example has been introduced to illustrate the working mode of the revision techniqu