Charge distribution in two-dimensional electrostatics

We examine the stability of ringlike configurations of N charges on a plane interacting through the potential $V(z_1,...,z_N)=\sum_i |z_i|^2-\sum_{i<j} ln|z_i-z_j|^2$. We interpret the equilibrium distributions in terms of a shell model and compare predictions of the model with the results of numerical simulations for systems with up to 100 particles.Comment: LaTe

10. DIAGNÓSTICO DE LA IMPLEMENTACIÓN DE LA NORMA NIIF (NIC 41) EN LAS EMPRESAS GANADERAS DEDICADAS A LA CRÍA DE GANADO BOVINO EN LA REGIÓN DEL BAJO CAUCA ANTIOQUEÑO

El establecimiento de las Normas Internacionales de Información Financiera (NIIF) y la NIC 41 ( Norma Internacional de Contabilidad) en la ley 1314 de 2009, busca determinar la convergencia de los principios y normas de contabilidad e información financiera hacia los estándares internacionales, permitiendo la identificación y reconocimiento de los activos biológicos; por este motivo el grupo de investigación HUTIN (Huellas Tecnológicas de Investigación), desarrolló un proyecto en el cual se diagnosticó las empresas del sector ganadero dedicadas a la cría de ganado bovino de la región del Bajo Cauca Antioqueño implementen esta norma, ya que posibilita el reconocimiento económico de los activos biológicos, valor razonable y deducción de costos que son representativos en los estados financieros. Esto se logró a través de encuestas realizadas a empresas de la subregión del Bajo Cauca Antioqueño dedicadas a la cría de ganado bovino, obteniendo la información necesaria para documentar el proceso y obtener un estándar para ser implementado en el sector siendo una herramienta eficaz para alcanzar mercados globalizados y competitivos. Se percibe un bajo nivel en las empresas ganaderas sobre el proceso de implementación de la NIIF (NIC 41). La implementación de esta norma le permite al empresario del sector ganadero identificar el estado actual de sus activos biológicos e inventarios y poder deducirse costos significativos en el proceso productivo, contando con una información económica, contable y financiera fundamentales en la toma de decisiones

Evaluation of Physical Interaction during Walker-Assisted Gait with the AGoRA Walker: Strategies Based on Virtual Mechanical Stiffness

Smart walkers are commonly used as potential gait assistance devices, to provide physical and cognitive assistance within rehabilitation and clinical scenarios. To understand such rehabilitation processes, several biomechanical studies have been conducted to assess human gait with passive and active walkers. Several sessions were conducted with 11 healthy volunteers to assess three interaction strategies based on passive, low and high mechanical stiffness values on the AGoRA Smart Walker. The trials were carried out in a motion analysis laboratory. Kinematic data were also collected from the smart walker sensory interface. The interaction force between users and the device was recorded. The force required under passive and low stiffness modes was 56.66% and 67.48% smaller than the high stiffness mode, respectively. An increase of 17.03% for the hip range of motion, as well as the highest trunk’s inclination, were obtained under the resistive mode, suggesting a compensating motion to exert a higher impulse force on the device. Kinematic and physical interaction data suggested that the high stiffness mode significantly affected the users’ gait pattern. Results suggested that users compensated their kinematics, tilting their trunk and lower limbs to exert higher impulse forces on the device

The structure of the PapD-PapGII pilin complex reveals an open and flexible P5 pocket

P pili are hairlike polymeric structures that mediate binding of uropathogenic Escherichia coli to the surface of the kidney via the PapG adhesin at their tips. PapG is composed of two domains: a lectin domain at the tip of the pilus followed by a pilin domain that comprises the initial polymerizing subunit of the 1,000-plus-subunit heteropolymeric pilus fiber. Prior to assembly, periplasmic pilin domains bind to a chaperone, PapD. PapD mediates donor strand complementation, in which a beta strand of PapD temporarily completes the pilin domain's fold, preventing premature, nonproductive interactions with other pilin subunits and facilitating subunit folding. Chaperone-subunit complexes are delivered to the outer membrane usher where donor strand exchange (DSE) replaces PapD's donated beta strand with an amino-terminal extension on the next incoming pilin subunit. This occurs via a zip-in-zip-out mechanism that initiates at a relatively accessible hydrophobic space termed the P5 pocket on the terminally incorporated pilus subunit. Here, we solve the structure of PapD in complex with the pilin domain of isoform II of PapG (PapGIIp). Our data revealed that PapGIIp adopts an immunoglobulin fold with a missing seventh strand, complemented in parallel by the G1 PapD strand, typical of pilin subunits. Comparisons with other chaperone-pilin complexes indicated that the interactive surfaces are highly conserved. Interestingly, the PapGIIp P5 pocket was in an open conformation, which, as molecular dynamics simulations revealed, switches between an open and a closed conformation due to the flexibility of the surrounding loops. Our study reveals the structural details of the DSE mechanism

An Open-Source Social Robot Based on Compliant Soft Robotics for Therapy with Children with ASD

Therapy with robotic tools is a promising way to help improve verbal and nonverbal communication in children. The robotic tools are able to increase aspects such as eye contact and the ability to follow instructions and to empathize with others. This work presents the design methodology, development, and experimental validation of a novel social robot based on CompliAnt SofT Robotics called the CASTOR robot, which intends to be used as an open-source platform for the long-term therapy of children with autism spectrum disorder (CwASD). CASTOR integrates the concepts of soft actuators and compliant mechanisms to create a replicable robotic platform aimed at real therapy scenarios involving physical interaction between the children and the robot. The validation shows promising results in terms of robustness and the safety of the user and robot. Likewise, mechanical tests assess the robot’s response to blocking conditions for two critical modules (i.e., neck and arm) in interaction scenarios. Future works should focus on the validation of the robot’s effectiveness in the therapy of CwASD.</jats:p

lncRNA requirements for mouse acute myeloid leukemia and normal differentiation

A substantial fraction of the genome is transcribed in a cell type-specific manner, producing long non-coding RNAs (lncRNAs), rather than protein-coding transcripts. Here we systematically characterize transcriptional dynamics during hematopoiesis and in hematological malignancies. Our analysis of annotated and de novo assembled lncRNAs showed many are regulated during differentiation and mis-regulated in disease. We assessed lncRNA function via an in vivo RNAi screen in a model of acute myeloid leukemia. This identified several lncRNAs essential for leukemia maintenance, and found that a number act by promoting leukemia stem cell signatures. Leukemia blasts show a myeloid differentiation phenotype when these lncRNAs were depleted, and our data indicates that this effect is mediated via effects on the c-MYC oncogene. Bone marrow reconstitutions showed that a lncRNA expressed across all progenitors was required for the myeloid lineage, whereas the other leukemia-induced lncRNAs were dispensable in the normal setting

Engineering the Controlled Assembly of Filamentous Injectisomes in E. coli K-12 for Protein Translocation into Mammalian Cells.

Bacterial pathogens containing type III protein secretion systems (T3SS) assemble large needle-like protein complexes in the bacterial envelope, called injectisomes, for translocation of protein effectors into host cells. The application of these molecular syringes for the injection of proteins into mammalian cells is hindered by their structural and genomic complexity, requiring multiple polypeptides encoded along with effectors in various transcriptional units (TUs) with intricate regulation. In this work, we have rationally designed the controlled expression of the filamentous injectisomes found in enteropathogenic Escherichia coli (EPEC) in the nonpathogenic strain E. coli K-12. All structural components of EPEC injectisomes, encoded in a genomic island called the locus of enterocyte effacement (LEE), were engineered in five TUs (eLEEs) excluding effectors, promoters and transcriptional regulators. These eLEEs were placed under the control of the IPTG-inducible promoter Ptac and integrated into specific chromosomal sites of E. coli K-12 using a marker-less strategy. The resulting strain, named synthetic injector E. coli (SIEC), assembles filamentous injectisomes similar to those in EPEC. SIEC injectisomes form pores in the host plasma membrane and are able to translocate T3-substrate proteins (e.g., translocated intimin receptor, Tir) into the cytoplasm of HeLa cells reproducing the phenotypes of intimate attachment and polymerization of actin-pedestals elicited by EPEC bacteria. Hence, SIEC strain allows the controlled expression of functional filamentous injectisomes for efficient translocation of proteins with T3S-signals into mammalian cells

Conociendo a los tutores de Medicina Interna: nuevas necesidades para la formación

Introducción y objetivos Los tutores son los responsables de planificar el aprendizaje de los residentes. El objetivo de este trabajo es conocer la situación de los tutores de Medicina Interna en España y detectar áreas de mejora que puedan facilitar su trabajo. Material y métodos Encuestas online a tutores de Medicina Interna de mayo a julio de 2017 con análisis posterior de los datos. Resultados Respondieron 110 tutores, de 13 comunidades autónomas y hospitales de todos los niveles con docencia en Medicina Interna. Sesenta y tres fueron hombres (57, 3%), la media de edad fue de 48 años y tenían una experiencia como tutores de 8, 5 años. En el 88, 2% de los casos se respeta la ratio de cinco residentes por tutor; un 46% piensa que debería disminuirse esta ratio para optimizar su labor. Un tercio había sido elegido por el responsable del servicio y el 30% nunca ha realizado cursos sobre formación. La entrevista tutor-residentes es utilizada por la mayoría de los tutores (96, 4%) como herramienta de comunicación. En relación a las rotaciones, la cuarta parte no son planificadas por los tutores y, solo la mitad, contacta con los centros donde los residentes realizan las rotaciones externas. El 61% cree que no se realiza bien la evaluación de residentes, con muy escasa utilización de las nuevas herramientas de evaluación. Conclusiones Disminuir la ratio tutor/residente y la formación en técnicas de evaluación y desarrollo del aprendizaje podría mejorar la calidad de la tutorización. Introduction and objectives: Mentors are responsible for planning the residents’ learning. The aim of this study was to determine the situation of internal medicine mentors in Spain and detect areas of improvement that can facilitate their work. Material and methods: Online surveys were sent to internal medicine mentors from May to July 2017, the results of which were subsequently analysed. Results: A total of 110 mentors from 13 autonomous communities and from hospitals of all levels with courses in internal medicine responded to the survey. Of these mentors, 63 were men (57.3%), and the mean age was 48 years. The mean experience as mentors was 8.5 years. Some 88.2% of the cases had a ratio of 5 residents to 1 mentor; 46% of the mentors believed this ratio should be decreased to optimize their work. A third of the mentors were chosen by the heads of the department, and 30% had not previously taken courses on training. The mentor-resident interview was used by most mentors (96.4%) as a communication tool. A quarter of the rotations were not planned by the mentors, and only half had contact with the centres where the residents performed the external rotations. Sixty-one percent of the mentors were of the opinion that resident assessments were not conducted properly, with very little use of the new assessment tools. Conclusions: Reducing the mentor-resident ratio and adding training in assessment techniques and learning development could improve the quality of the mentoring

Adverse effects of the antimalaria drug, mefloquine: due to primary liver damage with secondary thyroid involvement?

BACKGROUND: Mefloquine is a clinically important antimalaria drug, which is often not well tolerated. We critically reviewed 516 published case reports of mefloquine adverse effects, to clarify the phenomenology of the harms associated with mefloquine, and to make recommendations for safer prescribing. PRESENTATION: We postulate that many of the adverse effects of mefloquine are a post-hepatic syndrome caused by primary liver damage. In some users we believe that symptomatic thyroid disturbance occurs, either independently or as a secondary consequence of the hepatocellular injury. The mefloquine syndrome presents in a variety of ways including headache, gastrointestinal disturbances, nervousness, fatigue, disorders of sleep, mood, memory and concentration, and occasionally frank psychosis. Previous liver or thyroid disease, and concurrent insults to the liver (such as from alcohol, dehydration, an oral contraceptive pill, recreational drugs, and other liver-damaging drugs) may be related to the development of severe or prolonged adverse reactions to mefloquine. IMPLICATIONS: We believe that people with active liver or thyroid disease should not take mefloquine, whereas those with fully resolved neuropsychiatric illness may do so safely. Mefloquine users should avoid alcohol, recreational drugs, hormonal contraception and co-medications known to cause liver damage or thyroid damage. With these caveats, we believe that mefloquine may be safely prescribed in pregnancy, and also to occupational groups who carry out safety-critical tasks. TESTING: Mefloquine's adverse effects need to be investigated through a multicentre cohort study, with small controlled studies testing specific elements of the hypothesis

Aportes al conocimiento del sistema productivo de cultivo de la mora (Rubus glaucus Benth) en Colombia

Varios estudios que examinan el cultivo de la mora en Colombia muestran que esta actividad es realizada por pequeños y medianos agricultores. En muchas regiones constituye una de las principales fuentes de ingresos; generación de empleo rural; oferta de alimento y de agroindustria. En este trabajo se revisaron más de 180 documentos distribuidos entre artículos divulgativos, técnicos y científicos, publicados en boletines, manuales, cartillas, seminarios y cursos; además, resultados de trabajos de investigación, tesis de pregrado y artículos científicos publicados en revistas seriadas e indexadas. Este es resultado de la búsqueda la literatura de la agronomía del sistema productivo de la mora en la red, en la Biblioteca Agropecuaria de Colombia (BAC), en las bibliotecas de de la Universidad Nacional de Colombia y en las bibliotecas de los investigadores del CI La Selva de Corpoica. Para analizar la literatura sobre la agronomía y las prácticas de manejo agronómico de la mora (distribución espacial, trazado y siembra, propagación, tutorado, poda, entre otras). Del manejo agronómico se han escrito diversas publicaciones unas más profundas que otras, estas se caracterizan porque para la mayoría de las practicas agronómicas se carece de un sustento que las valide, para los diferentes ambiente y genotipos y muchas de ellas son el resultado de la observación, del sentido común y de adaptación de otro sistema productivo. Esta literatura surge en la década de 50’s, en la de los 70’ se dan las versiones más integrales del sistema productivo y durante la década de los 90’s, es el periodo dorado cuando se consolida y se presentan los trabajos mas completos, aun todavía faltando, la integralidad entre genotipo, ambiente y la interacción entre estos.Mora-Rubus ulmifoliu