Quantum point contacts as heat engines

The efficiency of macroscopic heat engines is restricted by the second law of thermodynamics. They can reach at most the efficiency of a Carnot engine. In contrast, heat currents in mesoscopic heat engines show fluctuations. Thus, there is a small probability that a mesoscopic heat engine exceeds Carnot's maximum value during a short measurement time. We illustrate this effect using a quantum point contact as a heat engine. When a temperature difference is applied to a quantum point contact, the system may be utilized as a source of electrical power under steady state conditions. We first discuss the optimal working point of such a heat engine that maximizes the generated electrical power and subsequently calculate the statistics for deviations of the efficiency from its most likely value. We find that deviations surpassing the Carnot limit are possible, but unlikely.Comment: 9 pages, 2 figures. Contribution to the Physica E special issue on "Frontiers in quantum electronic transport" in memory of Markus Buttiker. Published versio

Truth and Reconciliation Commissions: A Needed Force in Alaska?

Truth and Reconciliation Commissions are official, temporary bodies used for communities to come to terms with past violence, promote education and awareness of historic trauma, and to provide recognition and closure for victims and successors. By bringing past issues to light, such commissions promote healing and allow these communities to move forward. Although the Commission on Truth and Reconciliation in South Africa after the Apartheid-era is best known, several similar commissions have been established throughout the globe and within the United States. This paper compares commissions from South Africa, El Salvador, South Korea, and Canada with those that have been established in the United States to examine whether such a commission would be useful in Alaska to address current social problems in the state

"Cacheos" in argentine soccer stadiums: Between massive suspicion and selectivity

El cacheo, revisión que realiza un agente de seguridad, pública o privada, palpando con sus manos a otra persona en búsqueda de objetos prohibidos, es una práctica ampliamente extendida en el ingreso a los estadios de fútbol en la Argentina. A lo largo de este artículo proponemos analizar la práctica de cacheos masivos como una parte central de los dispositivos de seguridad en los partidos de fútbol. Abordamos este estudio a través de la revisión bibliográfica, entrevistas a trabajadorxs de seguridad y la lectura de la legislación vigente en seguridad deportiva. En ese sentido, encontramos que los cacheos no están regulados legalmente. De esto se deriva que hablamos de una práctica cuyo orden y gestión no está reglamentado, dejando un amplio margen de discrecionalidad a lxs trabajadorxs de seguridad que la aplican. Entre las lógicas de la sospecha masiva que habilita un estado de excepción de facto y la selectividad particular que estigmatiza a los sectores populares, analizamos cómo la discrecionalidad es la regla de un proceso clave en la gestión de la seguridad en el fútbol argentino.The “cacheos”, a review carried out by a security agent, public or private, feeling with their hands other people in search of prohibited objects, is a widely extended practice when entering soccer stadiums in Argentina. Throughout this article we propose to analyze the practice of mass “cacheos” as a central part of the security devices in soccer matches. We approached this study through a bibliographic review, interviews with security workers and the reading of the current legislation on sports safety. In that sense, we find that searches are not legally regulated. From this it follows that we are talking about a practice whose order and management is not regulated, leaving a wide margin of discretion to the security workers who apply it. Between the logic of the massive suspicion that enables a de facto state of exception and the particular selectivity that stigmatizes the popular sectors, we analyze how discretion is the rule of a key process in the management of security in Argentine soccer.Fil: Rosa, Sebastian Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Humanidades y Ciencias Sociales. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales; Argentin

A dataset comprising four micro-computed tomography scans of freshly fixed and museum earthworm specimens

Background: Although molecular tools are increasingly employed to decipher invertebrate systematics, earthworm (Annelida: Clitellata: ‘Oligochaeta’) taxonomy is still largely based on conventional dissection, resulting in data that are mostly unsuitable for dissemination through online databases. In order to evaluate if micro-computed tomography (μCT) in combination with soft tissue staining techniques could be used to expand the existing set of tools available for studying internal and external structures of earthworms, μCT scans of freshly fixed and museum specimens were gathered. Findings: Scout images revealed full penetration of tissues by the staining agent. The attained isotropic voxel resolutions permit identification of internal and external structures conventionally used in earthworm taxonomy. The μCT projection and reconstruction images have been deposited in the online data repository GigaDB and are publicly available for download. Conclusions: The dataset presented here shows that earthworms constitute suitable candidates for μCT scanning in combination with soft tissue staining. Not only are the data comparable to results derived from traditional dissection techniques, but due to their digital nature the data also permit computer-based interactive exploration of earthworm morphology and anatomy. The approach pursued here can be applied to freshly fixed as well as museum specimens, which is of particular importance when considering the use of rare or valuable material. Finally, a number of aspects related to the deposition of digital morphological data are briefly discussed

Development and validation of a new analytical method based on UV-visible spectroscopy for quantification of ceftaroline fosamil in powder for injection

Quantification of drugs is an essential part for ensuring quality, safety and efficacy of pharmaceutical formulations. For this, validated methods must be used in order to guarantee analytical reliability during monitoring in clinical studies and quality control. In the present study, we aim to develop a reliable, accurate, accessible and rapid UV-VIS spectrophotometry method for quantification of ceftaroline fosamil in powder for intravenous administration. Each analyzed solution was prepared individually and the only reagent used was Milli-Q water, as a solvent, making the method eco-friendly. The absorbances were measured at 242 nm, the peak absorbance found for the drug. The developed method was validated according to ICH and ANVISA guidelines, proving to be specific and demonstrating good linearity in the concentration range of 5 μg.mL-1 to 15 μg.mL-1, with determination (r2) and correlation coefficients (r) equal to 0.9999. The limits of detection and quantification found were acceptable (0.51 μg.mL-1 and 1.55 μg.mL-1, respectively).  The method exhibited excellent intermediate precision and repeatability, with relative standard deviation values of 0.87% and 0.98%, respectively. Furthermore, the method’s accuracy was confirmed, showing a mean recovery of 100 ± 2.67%. Additionally, the robustness was assayed and confirmed using Plackett-Burmann design. In conclusion, the method can easily be applied for routine quality control analysis

Fault detection and isolation for a wind turbine benchmark using a mixed Bayesian/Set-membership approach

This paper addresses the problem of fault detection and isolation of wind turbines using a mixed Bayesian/Set-membership approach. Modeling errors are assumed to be unknown but bounded, following the set-membership approach. On the other hand, measurement noise is also assumed to be bounded, but following a statistical distribution inside the bounds. To avoid false alarms, the fault detection problem is formulated in a set-membership context. Regarding fault isolation, a new fault isolation scheme that is inspired on the Bayesian fault isolation framework is developed. Faults are isolated by matching the fault detection test results, enhanced by a complementary consistency index that measures the certainty of not being in a fault situation, with the structural information about the faults stored in the theoretical fault signature matrix. The main difference with respect to the classical Bayesian approach is that only models of fault-free behavior are used. Finally, the proposed FDI method is assessed against the wind turbine FDI benchmark proposed in the literature, where a set of realistic fault scenarios in wind turbines are proposed.Peer Reviewe

Development and validation of a new analytical method based on UV-visible spectroscopy for quantification of ceftaroline fosamil in powder for injection

Quantification of drugs is an essential part for ensuring quality, safety and efficacy of pharmaceutical formulations. For this, validated methods must be used in order to guarantee analytical reliability during monitoring in clinical studies and quality control. In the present study, we aim to develop a reliable, accurate, accessible and rapid UV-VIS spectrophotometry method for quantification of ceftaroline fosamil in powder for intravenous administration. Each analyzed solution was prepared individually and the only reagent used was Milli-Q water, as a solvent, making the method eco-friendly. The absorbances were measured at 242 nm, the peak absorbance found for the drug. The developed method was validated according to ICH and ANVISA guidelines, proving to be specific and demonstrating good linearity in the concentration range of 5 μg.mL-1 to 15 μg.mL-1, with determination (r2) and correlation coefficients (r) equal to 0.9999. The limits of detection and quantification found were acceptable (0.51 μg.mL-1 and 1.55 μg.mL-1, respectively). The method exhibited excellent intermediate precision and repeatability, with relative standard deviation values of 0.87% and 0.98%, respectively. Furthermore, the method’s accuracy was confirmed, showing a mean recovery of 100 ± 2.67%. Additionally, the robustness was assayed and confirmed using Plackett-Burmann design. In conclusion, the method can easily be applied for routine quality control analysis

ARQUEOLOGIA COMUNITÁRIA NO BAIXO PAPALOAPAN: USO E REUSO DE COLEÇÕES ARQUEOLÓGICAS POR MORADORES DE TLACOJALPAN, ESTADO DE VERACRUZ, MÉXICO.

    RESUMEN: Este artículo preliminar tiene por objetivo difundir información sobre las colecciones de artefactos encontradas y mantenidas por los pobladores de la comunidad de Tlacojalpan, región del Bajo Papaloapan, estado de Veracruz – México. La investigación de caracterización y registro de estas colecciones se inició con el proyecto “El Barro que Habla: estudio de las colecciones privadas de pobladores de la región de Tlacojalpan, Paraíso del Novillero y Otatitlán, Bajo Papaloapan, Veracruz – México”, que se desarrolla desde 2019 en alianza con investigadores y estudiantes del Museo Comunitario La Casa de las Mariposas de Tlacojalpan. La nota sobre lienzo pretende presentar nuevas colecciones encontradas por los pobladores de la región del bajo Papaloapan y busca desarrollar una arqueología colaborativa y comunitaria entre la gente y la cultura material. Palabras clave: Arqueología Comunitaria y Colaborativa. Caracterización y documentación. Colecciones arqueológicas. Usos y reutilizaciones pasadas.     &nbsp