Coherent phonon transport in short-period two-dimensional superlattices of graphene and boron nitride

Promoting coherent transport of phonons at material interfaces is a promising strategy for controlling thermal transport in nanostructures and an alternative to traditional methods based on structural defects. Coherent transport is particularly relevant in short-period heterostructures with smooth interfaces and long-wavelength heat-carrying phonons, such as two-dimensional superlattices of graphene and boron nitride. In this work, we predict phonon properties and thermal conductivities in these superlattices using a normal mode decomposition approach. We study the variation of the frequency dependence of these properties with the periodicity and interface configuration (zigzag and armchair) for superlattices with period lengths within the coherent regime. Our results showed that the thermal conductivity decreases significantly from the first period length (0.44 nm) to the second period length (0.87 nm), 13% across the interfaces and 16% along the interfaces. For greater periods, the conductivity across the interfaces continues decreasing at a smaller rate of 11 W/mK per period length increase (0.43 nm), driven by changes in the phonon group velocities (coherent effects). In contrast, the conductivity along the interfaces slightly recovers at a rate of 2 W/mK per period, driven by changes in the phonon relaxation times (diffusive effects). By changing the interface configuration from armchair to zigzag, the conductivities for all period lengths increase by approximately 7% across the interfaces and 19% along the interfaces

Estudio de viabilidad para la emisión de títulos de deuda para financiar la ampliación del colegio balandra cruz del sur

empresas. Nuestra empresa a analizar, PREDUCA S.A, se ha desenvuelto en el sector educativo clase alta, manteniendo un prestigio por 17 años, lo cual la coloca como una de las mejores dentro de su estrato social. Su objetivo de reestructuración de pasivos y expansión futura, nos llevaron a establecer pautas para la utilización de nuevas herramientas de financiamiento. La emisión de obligaciones es una herramienta, conocida y utilizada en varios países incluidos el nuestro, que ha dado paso a un mayor desarrollo en el mercado de capitales ya que se muestra como una opción rentable al momento de invertir. Los análisis de los estados financieros de nuestra empresa en mención fueron factores cruciales para poder determinar la factibilidad de una emisión, además de una estrategia de introducción de este tipo de empresas en el mercado de valores, ya que de incursionar PREDUCA S.A. en este mercado sería la primera en su clase y sector. Las oportunidades y amenazas que una decisión como esta conlleva y los beneficios futuros asociados son tratados en nuestro estudio, a fin de dar al lector una visión del entorno de la empresa y proporcionar una guía de procedimientos a seguir en caso de realizarse una emisión de obligaciones. Todo ello asociado con la experiencia tanto al interior de nuestro país, la realidad que se ha vivido en los últimos años en nuestro mercado de obligaciones conjuntamente con lo sucedido en países latinoamericanos, nos muestra el escenario en que se desenvolvería PREDUCA S.A. al momento de emitir una obligación

The development and first validation of the “Preterm social, cognitive, health and learning outcomes” (Pre-School) socioeconomics indicators inventory

Background: The consequences of preterm birth, to the individual and society at large, remain a major financial, emotional, social and personal burden in all countries. A complex infuence network between the family socioeconomic status, nutrition and infant social interactions determines early childhood environment. The socioeconomic characteristics of families and households define much of the starting conditions and the posible future development of any newborn. Aim: To develop a socioeconomics indicators inventory specifically focused on preterm children, in order to characterize their early childhood environment to evaluate potential social affordances of infants under 24 months of age. Methods: The process was divided into four phases: questionnaire development (items and domains generation), pilot testing, validation and exploratory analysis. The final version of the PRE-SCHOOL questionnaire consisted of 190 items, each related to one or more of eight domains (personal data, family situation, health status, economical situation, level of education, social network, leisure and residence conditions). For the exploratory and validation analysis, 52 children were recruited. The parent interview was conducted by two specially trained social workers when the child reached 24 months of age. Internal consistency of the questionnaire was high for all domains (Cronbach’s a coefficient of 0.964). Conclusions: The social and economic contexts define spaces of possibility that directly affect the evolution and life development of each newborn. The PRE-SCHOOL socioeconomics indicators inventory improves the anamnesis process in preterm infants at risk of cognitive impairement. We need to increased socioecnomical informations of the early childhood enviroment in order to propose focused family-centred cost-effective interventions to improve cognitive development

Learning to breathe: developmental phase transitions in oxygen status

Plants are developmentally disposed to considerable changes in oxygen availability, yet our understanding of the importance of hypoxia is almost entirely limited to stress biology. Differential patterns of the abundance of oxygen, nitric oxide (.NO) and reactive oxygen species (ROS), and redox potential occur in organs and meristems, and examples are emerging in the literature of mechanistic relationships of these to development. Here, we describe the convergence of these cues in meristematic and reproductive tissues, and discuss the evidence for regulated hypoxic niches, within which oxygen-, ROS-, .NO- and redox-dependent signalling curate developmental transitions in plants

Circular lean product-service systems design: A literature review, framework proposal and case studies

In recent years, the Service Sector has received an increasing attention from both academics and practitioners. The transition from traditional manufacturing to service-oriented integrated systems has given rise to the such called: “Servitisation Revolution”, which today is a relevant revenue generator. The definition of “Product-Service Systems (PSS)” calls for an expanded value creation system through the addition of competitive advantages based on value-added services to previous companies\u27 pure product offerings. These product-services bundled solutions have been recognized as being one of the most efficient techniques towards the achievement of resource-efficient and sustainable economies. PSS paradigm has grown beyond expectations, becoming a common term among publications of the most recognized academic journals and international conferences, and a highly discussed topic across a broad range of industrial sectors. However, recent trends based on scientific and grey literature suggest analysing the compatibility of PSS with other principles, methods and tools such as “circular” and “lean” thinking, which may help to enhance the intrinsic environmentally sustainability advantage that is refer at the first PSS definitions, but that has, unfortunately, faded through time. This paper analyses how the PSS paradigm can benefit from the “circular economy” and “lean” principles. The followed research methodology included a literature review, which aims to identify those principles, methods and tools which can help to modify each stage of a traditional PSS towards a Circular Lean PSS. Furthermore, a first Circular Lean PSS Design Framework is proposed and described. This framework is validated empirically through two case studies supported by two vessel-building companies. Further research is suggested to validate the proposed framework in different industries

Implicaciones jurídicas del control de convencionalidad en el ámbito jurisdiccional en colombia.

There was perceived that the control exists of convencionalidad´s exercised by an international court with full powers which have been granted or conceived for he them wasgiving birth members on instruments having adhered and to be ratified of I waste internationally, since it is the case of pacts, treats and agreements. That force the civil servants entrusted to issue the law, administrative acts and / or you reform to the constitution, the duty to be adapted by the content of the top internal norm, as of the international dispositions as for Law Human beings. Of there that every person without any distinction of creed, race, sex, political or cultural ideology, can come to two international organs of regional character (for the Americas) which are the Inter-American Commission of Human rights (CIDH) and the Inter-American Court of Human rights (CorteIDH), whose functions are of check, emission ofconcepts and later sanctions and sentences to the conditions departs from the above mentioned system. Under the guarantee of general beginning of the international public law, which in the execution are reflected as a supranational instance, which he contributes as a form of control and later decrease as for the constitutive facts of violations and other affectations to the juridical goods of the partners which in certain occasions result to have protection small in the juridical internal classifications, reason for which one comes to the above mentioned international instances, which it has full powers to modify, to suppress and to adapt the laws without altering the sovereignty not the juridical area that generates internal commotion in the study divides taking as a source the obligatory nature of the beginning of international law.El control de convencionalidad ejercido por un tribunal internacional con facultades plenas las cuales han sido reconocidas y otorgadas por los países miembros al realizar la ratificación o adhesión de los instrumentos de derecho internacional como es el caso de pactos, tratados y convenios, que obligan a los funcionarios encargados de emitir la ley, actos administrativos y/o reformas a la constitución, el deber de adecuarse con el contenido de la norma superior interna, es decir, la Constitución Política de 1991, al igual que de las disposiciones internacionales en materia de Derecho Humanos. De ahí que toda persona sin distinción alguna de credo, raza, sexo, ideología política o cultural, puede acudir a dos órganos internacionales de carácter regional (para las Américas): La Comisión Interamericana de Derechos Humanos (CIDH) y la Corte Interamericana de Derechos Humanos (CorteIDH), cuyas funciones son de verificación, emisión de conceptos y posteriores sanciones y condenas a los Estados parte de dicho sistema. Bajo la garantía de principios generales del derecho público internacional, que en la ejecución se reflejan como una instancia supranacional, que contribuye como una forma de control y posterior disminución en cuanto a los hechos constitutivos de violaciones y demás afectaciones a los bienes jurídicos de los asociados, los cuales en ciertas ocasiones resultan tener poca protección en los ordenamientos jurídicos internos, razón por la cual se acude a dichas instancias internacionales, facultadas para modificar, suprimir y adecuar las leyes sin alterar la soberanía ni el ámbito jurídico que genere conmoción interna en los Estados parte, teniendo como fuente la obligatoriedad de los principios de derecho internacional

The neonicotinoid insecticide Imidacloprid repels pollinating flies and beetles at field-realistic concentrations

Neonicotinoids are widely used systemic insecticides which, when applied to flowering crops, are translocated to the nectar and pollen where they may impact upon pollinators. Given global concerns over pollinator declines, this potential impact has recently received much attention. Field exposure of pollinators to neonicotinoids depends on the concentrations present in flowering crops and the degree to which pollinators choose to feed upon them. Here we describe a simple experiment using paired yellow pan traps with or without insecticide to assess whether the commonly used neonicotinoid imidacloprid repels or attracts flying insects. Both Diptera and Coleoptera exhibited marked avoidance of traps containing imidacloprid at a field-realistic dose of 1 μg L-1, with Diptera avoiding concentrations as low as 0.01 μg L-1. This is to our knowledge the first evidence for any biological activity at such low concentrations, which are below the limits of laboratory detection using most commonly available techniques. Catch of spiders in pan traps was also slightly reduced by the highest concentrations of imidacloprid used (1 μg L-1), but catch was increased by lower concentrations. It remains to be seen if the repellent effect on insects occurs when neonicotinoids are present in real flowers, but if so then this could have implications for exposure of pollinators to neonicotinoids and for crop pollination. © 2013 Easton, Goulson

Effect of controlled disorder on quasiparticle thermal transport in Bi2_2Sr2_2CaCu2_2O8_8

Low temperature thermal conductivity, $\kappa$, of optimally-doped Bi2212 was studied before and after the introduction of point defects by electron irradiation. The amplitude of the linear component of $\kappa$ remains unchanged, confirming the universal nature of heat transport by zero-energy quasiparticles. The induced decrease in the absolute value of $\kappa$ at finite temperatures allows us to resolve a nonuniversal term in $\kappa$ due to conduction by finite-energy quasiparticles. The magnitude of this term provides an estimate of the quasiparticle lifetime at subkelvin temperatures.Comment: 5 pages including 2 .eps figuer

On a class of generalised Schmidt groups

In this paper families of non-nilpotent subgroups covering the non-nilpotent part of a finite group are considered. An $A_5$-free group possessing one of these families is soluble, and soluble groups with this property have Fitting length at most three. A bound on the number of primes dividing the order of the group is also obtained