316 research outputs found
Subtle sexual plumage color dimorphism and size dimorphism in a South American colonial breeder, the Monk Parakeet (Myiopsitta monachus)
Parrots (Psittacidae Family) are one of the most colorful groups of birds in the world, their colors produced both structurally and via unusual pigments (psittacofulvins). Most species are considered to be monogamous, and many have been viewed historically as sexually monomorphic and monochromatic. However, studies using morphometric analysis and spectrophotometric techniques have revealed sexual size dimorphism and also sexual plumage color dimorphism among some species. The Monk Parakeet (Myiopsitta monachus), a native parrot of South America, is an interesting species for the study of plumage coloration and size since it is considered sexually monochromatic and monomorphic. Furthermore, recent studies show that the Monk Parakeet has extra-bond paternity behavior and even breeding trios, which suggests that sexual selection may play an important role in this species, and that it might have sexually dimorphic plumage (albeit imperceptible by humans) and be dimorphic in size. Methods: For the determination of plumage color we used spectrophotometry in the range of avian vision (300-700 nm) and performed a morphological analysis. Results: Our spectrophotometric results indicate that the Monk Parakeet shows subtle sexual plumage color dimorphism in three (crown, nape and wing) out of twelve body regions. Similarly, our morphometric analysis showed that there are subtle sex differences in body size (bill and weight). Conclusions: Although the Monk Parakeet shows extra-bond paternity and breeding trio behaviors which could increase sexual dimorphism, these behaviors occur among highly related individuals; perhaps the high rate of inbreeding is responsible for the attenuation of sexual plumage color dimorphism and sex differences in body size observed.Fil: Morales, Macarena. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; ArgentinaFil: Gigena, Deysi J.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Benitez-Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Valdez, Diego Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin
Advanced control methods for Asymmetrical Half-bridge Flyback
—In this article, a power converter based on an asymmetrical half-bridge flyback topology is analyzed and optimized for
small form factor and fast-charging power adaptors. Two resonant
control methods, taking advantage of the forward and flyback
characteristics of the converter, as well as the benefits of each of
them depending of the operation point are discussed. The analysis
is nourished with the equivalent circuits in each phase of operation
and the equations that define them. Particularly innovative is the
proposed zero voltage resonant valley switching control method for
the mentioned converter; in this case, it is operated similarly to a
flyback converter, allowing safe output voltage ramp up, which is
one of the challenges that has limited the usage of this topology up to
now. The manuscript also describes how to achieve high efficiency
and power density using zero-voltage switching and zero-current
switching techniques over the full range of the input voltage and
the output load. Finally, the advantages of the proposed control
methods are demonstrated in a 65-W adaptor prototype achieving
a peak efficiency over 94.6% and an efficiency of 93.8% @ Vac ≥
100 V at full load over the range of the input voltage, as well as a
world-class power density of 35 W/in3 uncasedhis work was supported by Infineon Technologies AG by Contract OTRI 3770-05 and Contract OTRI 3770-0
Low-Cost Energy-Autonomous Sensor Nodes Through RF Energy Harvesting and Printed Technology
The irruption of Internet of Things and 5G in our society comes along with several technological challenges to overcome. From an overall perspective, the low-cost and environmental friendliness of these technologies need to be ensured for their universal deployment in different areas, starting with the sensors and finishing with the power sources. To address these challenges, the production and maintenance of a great number of sensor nodes incur costs, which include manufacturing and integration in mass of elements and sub-blocks, changing or recharging of batteries, as well as management of natural resources and waste. In this article, we demonstrate how Radio Frequency Energy Harvesting (RFEH) and printed flexible technology (a growing technology for sensors) can solve these concerns through costeffective mass-production and utilization of energy harvesting for the development of energy-autonomous nodes, as part of a wireless sensor network. We present as illustration a sprayed flexible relative humidity sensor powered with RFEH under the store-and-use principle.This work was partially supported by the ECSEL Joint Undertaking through the Electronic Component Systems for European Leadership Joint Undertaking under grant agreement No 737434. This Joint Undertaking receives support from the German Federal Ministry of Education and Research and the European Union’s Horizon 2020 research and innovation program and Slovakia, Netherlands, Spain, Italy. In addition, the Spanish Ministry of Education, Culture and Sport (MECD) and the European Union supported it through the pre-doctoral grant FPU16/01451 and the fellowship H2020-MSCA-IF-2017794885-SELFSENS
Differences in scapular upward rotation, pectoralis minor and levator scapulae muscle length between the symptomatic, the contralateral asymptomatic shoulder and control subjects: a cross-sectional study in a Spanish primary care setting
Objective To determine the potential differences in both
scapular positioning and scapular movement between the
symptomatic and asymptomatic contralateral shoulder, in
patients with unilateral subacromial pain syndrome (SAPS),
and when compared with participants free of shoulder
pain.
Setting Three different primary care centres.
Participants A sample of 73 patients with SAPS in their
dominant arm was recruited, with a final sample size of 54
participants.
Primary outcome measures The scapular upward
rotation (SUR), the pectoralis minor and the levator
scapulae muscles length tests were carried out.
Results When symptomatic shoulders and controls
were compared, an increased SUR at all positions (45°,
90° and 135°) was obtained in symptomatic shoulders
(2/3,98/8,96°, respectively). These differences in SUR
surpassed the minimal detectable change (MDC95)
(0,91/1,55/2,83° at 45/90/135° of shoulder elevation).
No differences were found in SUR between symptomatic
and contralateral shoulders. No differences were found in
either pectoralis minor or levator scapulae muscle length
in all groups.
Conclusions SUR was greater in patients with chronic
SAPS compared with controls at different angles of
shoulder elevation
Laser-Fabricated Reduced Graphene Oxide Memristors
Finding an inexpensive and scalable method for the mass production of memristors will be one of the key aspects for their implementation in end-user computing applications. Herein, we report pioneering research on the fabrication of laser-lithographed graphene oxide memristors. The devices have been surface-fabricated through a graphene oxide coating on a polyethylene terephthalate substrate followed by a localized laser-assisted photo-thermal partial reduction. When the laser fluence is appropriately tuned during the fabrication process, the devices present a characteristic pinched closed-loop in the current-voltage relation revealing the unique fingerprint of the memristive hysteresis. Combined structural and electrical experiments have been conducted to characterize the raw material and the devices that aim to establish a path for optimization. Electrical measurements have demonstrated a clear distinction between the resistive states, as well as stable memory performance, indicating the potential of laser-fabricated graphene oxide memristors in resistive switching applications.This work has been supported by the Spanish Ministry of Science, Innovation and Universities/FEDER-EU through the project TEC2017-89955-P, Iberdrola Foundation under its 2018 Research Grant Program, the pre-doctoral grants FPU16/01451, FPU16/04043, and the JSPS KAKENHI through grant number JP18k04275
Sistema informático móvil para el apoyo al cese tabáquico mediante mensajes motivacionales personalizados
El proyecto SmokeFreeBrain estudia la efectividad de una variedad de intervenciones con el
objetivo de dejar de fumar usando diferentes técnicas. Uno de los métodos consiste en la aplicación de
un protocolo de intervención basado en terapia del comportamiento mediante el uso de aplicaciones
móviles, gamificación y envío de mensajes motivacionales de apoyo al paciente en tratamiento para el
cese tabáquico o al usuario que está intentando dejar de fumar. Se pretende aprovechar el uso
generalizado de los dispositivos móviles en el día a día como una herramienta de control y apoyo,
aplicando teoría de juegos al progreso del usuario en su cese tabáquico, y con el uso de un sistema
recomendador para seleccionar mensajes motivacionales acordes al perfil del usuario. El sistema
desarrollado contempla la creación de una aplicación móvil para llevar a cabo dicho protocolo de
intervención, así como el servidor que gestione las peticiones de los usuarios, contenga el sistema
recomendador diseñado, tenga la capacidad de mandar mensajes motivacionales a los usuarios y recoja
información de uso sobre la aplicación para su futuro análisis.The SmokeFreeBrain studies the effectiveness of a variety of interventions with the goal of quitting
smoking by using different techniques. One of the methods consists in the application of an intervention
protocol based on behavioral therapy, applying mobile applications, gamification and sending
motivational messages of support, both to the patient in treatment for smoking cessation and, to the user
who is trying to quit smoking independently. It aims to take advantage of the widespread daily use of
mobile devices as a tool for monitor and support, applying game theory to the user progress in their
smoking cessation, and recommendation systems for the selection of motivational messages according to
the user profile. The system developed for this purpose consists of a mobile application that allows
carrying out the intervention protocol as well as the server that manages user requests, implements the
recommender system, send motivational messages to users and register usage data to analyze
effectiveness.Plan Propio de la Universidad de Sevilla Proyecto: 2017/0000096
Memcapacitor and Meminductor Circuit Emulators: A Review
This research was funded by the Japanese KAKENHI through Grant Number JP18k04275 and Spanish Ministry of Education, Culture, and Sport (MECD), through Project TEC2017-89955-P and Grant Numbers: FPU16/01451 and FPU16/04043.In 1971, Prof. L. Chua theoretically introduced a new circuit element, which exhibited a different behavior from that displayed by any of the three known passive elements: the resistor, the capacitor or the inductor. This element was called memristor, since its behavior corresponded to a resistor with memory. Four decades later, the concept of mem-elements was extended to the other two circuit elements by the definition of the constitutive equations of both memcapacitors and meminductors. Since then, the non-linear and non-volatile properties of these devices have attracted the interest of many researches trying to develop a wide range of applications. However, the lack of solid-state implementations of memcapacitors and meminductors make it necessary to rely on circuit emulators for the use and investigation of these elements in practical implementations. On this basis, this review gathers the current main alternatives presented in the literature for the emulation of both memcapacitors and meminductors. Different circuit emulators have been thoroughly analyzed and compared in detail, providing a wide range of approaches that could be considered for the implementation of these devices in future designs.Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)
Japan Society for the Promotion of Science
Grants-in-Aid for Scientific Research (KAKENHI)
JP18k04275Spanish Ministry of Education, Culture, and Sport (MECD)
TEC2017-89955-P
FPU16/01451
FPU16/0404
Which is the best supply chain for perishable fruits, Lean or Agile?
1 recurso en línea (páginas 294-305) : ilustraciones color.It is estimated that one-third of global fruit production is lost or damaged. In developing countries, post-harvest
losses that often exceed 50%, together with the growth of global consumption, generate various problems
of supply and distribution throughout the supply chain. This article evaluates the structure of the mango supply chain in Cundinamarca-Bogotá. Using a dynamic model system, the current structure was evaluated in
comparison with Lean and Agile supply chains. The structures were measured through the performance indicators of quality, responsiveness, logistic operations and costs. This study showed that the Lean and Agile supply chains improved the performance of the current chain in all cases although not for all the involved actors. However, there was a trade-off that indicated a need for a future evaluation of Agile-Lean structures for perishable fruit chains.Se estima que un tercio de la producción mundial de frutas se pierde o se daña, en los países en desarrollo las
pérdidas poscosecha a menudo son superiores al 50%, el crecimiento del consumo mundial genera diversos
problemas de abasto y distribución a lo largo de la cadena de suministro. Este artículo evalúa la estructura de
la cadena del mango en Cundinamarca-Bogotá, mediante un modelo de dinámica de sistemas, la estructura
actual se evaluó frente a las cadenas lean y ágil. Las estructuras se estudiaron respecto a las medidas de desempeño de calidad, capacidad de respuesta, operaciones logísticas y costos. Se encuentra que las cadenas lean y ágil mejoran el desempeño de la cadena en todos los casos, aunque no para todos los actores, se evidencia la existencia de trade-off, lo que presenta la necesidad de evaluar a futuro estructuras combinadas ágil y lean para la cadena de suministro de frutas perecederas.Bibliografía: páginas 304-30
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