Near-equilibrium measurement of quantum size effects using Kelvin probe force microscopy

In nano-structures such as thin films electron confinement results in the quantization of energy levels in the direction perpendicular to the film. The discretization of the energy levels leads to the oscillatory dependence of many properties on the film thickness due to quantum size effects. Pb on Si(111) is a specially interesting system because a particular relationship between the Pb atomic layer thickness and its Fermi wavelength leads to a periodicity of the oscillation of two atomic layers. Here, we demonstrate how the combination of scanning force microscopy (SFM) and Kelvin probe force microscopy (KPFM) provides a reliable method to monitor the quantum oscillations in the work function of Pb ultra-thin film nano-structures on Si(111). Unlike other techniques, with SFM/KPFM we directly address single Pb islands, determine their height while suppressing the influence of electrostatic forces, and, in addition, simultaneously evaluate their local work function by measurements close to equilibrium, without current-dependent and non-equilibrium effects. Our results evidence even-odd oscillations in the work function as a function of the film thickness that decay linearly with the film thickness, proving that this method provides direct and precise information on the quantum states.Comment: This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Nanoscale, copyright Royal Society of Chemistry after peer review. To access the final edited and published work see doi belo

Bianchi Cosmologies: New Variables and a Hidden Supersymmetry

We find a supersymmetrization of the Bianchi IX cosmology in terms of Ashtekar's new variables. This provides a framework for connecting the recent results of Graham and those of Ryan and Moncrief for quantum states of this model. These states are also related with the states obtained particularizing supergravity for a minisuperspace. Implications for the general theory are also briefly discussed.Comment: 15 Pages, RevTex, NSF-ITP-93-9

A high throughput screen for next-generation leads targeting malaria parasite transmission.

Spread of parasite resistance to artemisinin threatens current frontline antimalarial therapies, highlighting the need for new drugs with alternative modes of action. Since only 0.2–1% of asexual parasites differentiate into sexual, transmission-competent forms, targeting this natural bottleneck provides a tangible route to interrupt disease transmission and mitigate resistance selection. Here we present a high-throughput screen of gametogenesis against a ~70,000 compound diversity library, identifying seventeen drug-like molecules that target transmission. Hit molecules possess varied activity profiles including male-specific, dual acting male–female and dual-asexual-sexual, with one promising N-((4-hydroxychroman-4- yl)methyl)-sulphonamide scaffold found to have sub-micromolar activity in vitro and in vivo efficacy. Development of leads with modes of action focussed on the sexual stages of malaria parasite development provide a previously unexplored base from which future therapeutics can be developed, capable of preventing parasite transmission through the population.post-print3903 K

Guía para facilitar la creación de empresas en el sector de la construcción de vivienda

Este trabajo de grado está orientado a estructurar los principios y procedimientos adecuados para la creación y gerencia de una empresa del sector de la construcción. Partiendo de un plan de negocios elaborado minuciosamente se pretende abarcar todas las posibles variables que confluyen en la creación de un negocio nuevo, pasando desde lo administrativo, financiero, comercial, legal, técnico y recursos humanos. La importancia del trabajo radica en tener una formula sencilla para el lector o para la persona que vaya a ejecutar su idea, se encontrara herramientas suficientes para saber si es factible y rentable comenzar a estructurar su nuevo negocio en el sector de la construcción. Para ejecutar la construcción de una edificación en el sector privado se necesita conocimientos de mercadeo, finanzas, comercialización, planeación urbana, diseño urbano y de arquitectura, todo tipo de ingenierías, derecho comercial y urbano, administrativos y manejo de riesgos entre otros. Lo más importante es cumplir con que el proyecto sea rentable para los inversionistas. También cumplir con importantes aspectos como el mercado objetivo, el alcance del proyecto, las normas vigentes de ordenamiento territorial, las normas ambientales y las normas técnicas colombianas (NTC). Y cumplir con las expectativas de todos los interesados. Igualmente se debe estudiar si el proyecto es viable, no solo si se tiene el flujo de caja suficiente para ejecutar todas las actividades desde la pre-factibilidad y factibilidad, la planeación, las ventas, su construcción, puesta en marcha y cierre sino también estudiar el mercado y el análisis financiero del mismo.This work of degree is aimed at structuring the principles and procedures for the establishment and management of an enterprise in the construction sector. On the basis of a business plan carefully crafted is meant to cover all possible variables that converge in the creation of a new business, passing from the administrative, financial, commercial, legal, technical and human resources. The importance of the work lies in having a simple formula for the reader or for the person who is going to run your idea is found sufficient tools to know if it is feasible and rentable begin to structure your new business in the construction sector. To run the construction of a building in the private sector needs knowledge of marketing, finance, marketing, urban planning, urban design and architecture, all kinds of engineering, urban and commercial law, administrative and management of risks, among others. The most important thing is to comply with which the project sea rentable for investors. Also compliance with important aspects such as the target market, the scope of the project, the existing rules of territorial ordering, environmental standards and the Colombian Technical Standards (NTC). And meet the expectations of all concerned. There should also be studied if the project is viable, not only if you have adequate cash flow to implement all the activities from the pre-feasibility and feasibility studies, planning, sales, its construction, commissioning and closure but also to study the market and financial analysis of the same

A simulation framework for the design and evaluation of computational cameras

In the emerging field of computational imaging, rapid prototyping of new camera concepts becomes increasingly difficult since the signal processing is intertwined with the physical design of a camera. As novel computational cameras capture information other than the traditional two-dimensional information, ground truth data, which can be used to thoroughly benchmark a new system design, is also hard to acquire. We propose to bridge this gap by using simulation. In this article, we present a raytracing framework tailored for the design and evaluation of computational imaging systems. We show that, depending on the application, the image formation on a sensor and phenomena like image noise have to be simulated accurately in order to achieve meaningful results while other aspects, such as photorealistic scene modeling, can be omitted. Therefore, we focus on accurately simulating the mandatory components of computational cameras, namely apertures, lenses, spectral filters and sensors. Besides the simulation of the imaging process, the framework is capable of generating various ground truth data, which can be used to evaluate and optimize the performance of a particular imaging system. Due to its modularity, it is easy to further extend the framework to the needs of other fields of application. We make the source code of our simulation framework publicly available and encourage other researchers to use it to design and evaluate their own camera designs

Perfil antropométrico, composición corporal y somatotipo de remeros tradicionales de élite: Estudio transversal

Introduction: Given the importance of body composition in sports performance, it is vital to have references of elite athletes which serve as a guide when it comes to overseeing diet and training.The aim of this study was to describe the anthropometric values of an elite team of traditional rowers in order to build an anthropometric profile in this sport. Material and methods: A cross-sectional design with twenty elite, male traditional rowers aged at 29.3 (3.6) years reported to the laboratory on a single day at the start of the competitive season. Height, wingspan, body mass, 8 skinfolds, 2 bone diameters and 6 perimeters were measured by the same internationally certified anthropometrist. Anthropometric measurements were taken following the International Society of Advancement of Kinanthropometry (ISAK) protocol. Fat mass was calculated using different equations for athletes and muscle mass using the Lee equation. For the somatotype components, the Carter and Heath equation was applied.Results: elite traditional rowers had a wingspan of 189 (5.8) cm, body fat percentage of 8.0 (1.2)% (Carter), 8.0 (1.8) (Withers), 7.0 (1.2)% (Yuhasz), and 10.9 (1.1)% (Faulkner). Muscle mass was 43.3 (2.4)% (Lee). The somatotype was endo-mesomorphic with endomorphy values of 3.5 (0.4), mesomorphy 4.7 (0.6) and ectomorphy 2.4 (3.5).Conclusion: These results suggest that wingspan seems to be of great importance for elite traditional rowers; while average height may not be as important for performance as wingspan. Meanwhile, reducing body fat percentage is likely to be beneficial in order to achieve elite rowing status.Introducción: Debido a la importancia que la composición corporal tiene en el rendimiento deportivo es necesario disponer de referencias de deportistas élite que sirvan de guía a la hora de orientar la dieta y el entrenamiento. Material y métodos: El estudio fue diseñado como un estudio transversal que incluyó a veinte remeros tradicionales de élite de 29,3(3,6) años de edad que acudieron al laboratorio un sólo día al comienzo del período competitivo. La altura, envergadura, masa corporal, 8 pliegues cutáneos, 2 diámetros óseos y 6 perímetros fueron determinados por el mismo antropometrista internacionalmente certificado. Las medidas fueron recogidas siguiendo el protocolo de la Sociedad Internacional para el avance de la Cineantropometría (ISAK). La masa grasa se calculó utilizando diferentes ecuaciones para deportistas, y la masa muscular mediante la ecuación de Lee. Los componentes del somatotipo fueron estimados mediante la ecuación Carter y Heath.Resultados: Se observó que los remeros de elite tenían una envergadura de 189 (5,8) cm, un porcentaje de grasa corporal de 8,0 (1,2)% según las ecuaciones de Carter, 8,0 (1,8) de Withers; 7,0 (1,2)% de Yuhasz, y 10,9 (1,1)% de Faulkner. La masa muscular fue de 43,3 (2,4)% según la ecuación de Lee. El somatotipo fue endo-mesomorfo con valores de endomorfia de 3,5(0,4), mesomorfia de 4,7(0,6) y ectomorfia de 2,4 (3,5). Conclusiones: Estos resultados sugieren que la envergadura parece ser de gran importancia para los remeros de élite, mientras que la altura promedio puede no ser tan importante para el rendimiento. Por su parte, reducir el porcentaje de grasa corporal es probablemente beneficioso para lograr un buen rendimiento en este deporte

A simulation framework for the design and evaluation of computational cameras

In the emerging field of computational imaging, rapid prototyping of new camera concepts becomes increasingly difficult since the signal processing is intertwined with the physical design of a camera. As novel computational cameras capture information other than the traditional two-dimensional information, ground truth data, which can be used to thoroughly benchmark a new system design, is also hard to acquire. We propose to bridge this gap by using simulation. In this article, we present a raytracing framework tailored for the design and evaluation of computational imaging systems. We show that, depending on the application, the image formation on a sensor and phenomena like image noise have to be simulated accurately in order to achieve meaningful results while other aspects, such as photorealistic scene modeling, can be omitted. Therefore, we focus on accurately simulating the mandatory components of computational cameras, namely apertures, lenses, spectral filters and sensors. Besides the simulation of the imaging process, the framework is capable of generating various ground truth data, which can be used to evaluate and optimize the performance of a particular imaging system. Due to its modularity, it is easy to further extend the framework to the needs of other fields of application. We make the source code of our simulation framework publicly available and encourage other researchers to use it to design and evaluate their own camera designs

A new common functional coding variant at the DDC gene change renal enzyme activity and modify renal dopamine function.

The intra-renal dopamine (DA) system is highly expressed in the proximal tubule and contributes to Na+ and blood pressure homeostasis, as well as to the development of nephropathy. In the kidney, the enzyme DOPA Decarboxylase (DDC) originating from the circulation. We used a twin/family study design, followed by polymorphism association analysis at DDC locus to elucidate heritable influences on renal DA production. Dense single nucleotide polymorphism (SNP) genotyping across the DDC locus on chromosome 7p12 was analyzed by re-sequencing guided by trait-associated genetic markers to discover the responsible genetic variation. We also characterized kinetics of the expressed DDC mutant enzyme. Systematic polymorphism screening across the 15-Exon DDC locus revealed a single coding variant in Exon-14 that was associated with DA excretion and multiple other renal traits indicating pleiotropy. When expressed and characterized in eukaryotic cells, the 462Gln variant displayed lower Vmax (maximal rate of product formation by an enzyme) (21.3 versus 44.9 nmol/min/mg) and lower Km (substrate concentration at which half-maximal product formation is achieved by an enzyme.)(36.2 versus 46.8 μM) than the wild-type (Arg462) allele. The highly heritable DA excretion trait is substantially influenced by a previously uncharacterized common coding variant (Arg462Gln) at the DDC gene that affects multiple renal tubular and glomerular traits, and predicts accelerated functional decline in chronic kidney disease