Influence of extrinsic contribution on the macroscopic properties of hard and soft lead zirconate titanate ceramics

In this work, the contribution of the extrinsic effect to the macroscopic properties in soft and hard lead zirconate titanate ceramics is directly evaluated. Close to the room temperature, poled hard ceramics show an anomalous behavior, which is notably different from that of soft ceramics, not only in dielectric but also in piezoelectric and elastic responses. Hence, at room temperature their properties are thermally stable and the losses are unusually low. It is suggested that two mechanisms are present, with one mechanism inhibiting the other.Peer ReviewedPostprint (published version

Cross-dataset evaluation of wearable fall detection systems using data from real falls and long-term monitoring of daily life

The evaluation of fall detection systems based on wearables is controversial as most studies in the literature benchmark their proposals against falls that are simulated by experimental subjects under unrealistic laboratory conditions. In order to systematically investigate the suitability of this procedure, this paper evaluates a wide set of artificial intelligence algorithms used for fall detection, when trained with a large number of datasets containing acceleration samples captured during the emulation of falls and ordinary movements and then tested with the signals of both actual falls and long-term traces collected from the constant monitoring of users during their daily routines. The results, based on a large number of repositories, show a remarkable degradation in all performance metrics (sensitivity, specificity and false alarm hourly rate) with respect to the typical case in which the detectors are tested with the same types of laboratory movements for which they were trained.Funding for open access charge: Universidad de Málaga / CBU

UMATUG: A dataset of inertial signals of older and young adults using a gerontologic simulator collected during instrumented Timed Up and Go (iTUG) tests

Timed Up and Go (TUG) test is one of the most popular clinical tools aimed at the assessment of functional mobility and fall risk in older adults. The automation of the analysis of TUG movements is of great medical interest not only to speed up the test but also to maximize the information inferred from the subjects under study. In this context, this article describes a dataset collected from a cohort of 69 experimental subjects (including 30 adults over 60 years), during the execution of several repetitions of the TUG test. In particular, the dataset includes the measurements gath- ered with four wearables devices embedding four sensors (accelerometer, gyroscope magnetometer and barometer) located on four body locations (waist, wrist, ankle and chest). As a particularity, the dataset also includes the same measurements recorded when the young subjects repeat the test while wearing a commercial geriatric simulator, consisting of a set of weighted vests and other elements intended to replicate the limitations caused by aging. Thus, the generated dataset also enables the investigation into the potential of such tools to emulate the actual dynamics of older individuals.Funding for open access charge: Partial funding for open access charge: Universidad de Málaga / CBUA This research was funded by the Spanish Ministry of Science, Innovation, and Universities ( MCIN/AEI/10.13039/50110 0 011033 ) and NextGenerationEU/PRTR Funds under grant TED2021- 130456B-I00, by Universidad de Málaga, Campus de Excelencia Internacional Andalucia Tech (grant B4-2023-12) and DIANA PAIDI research group

Unexpected dielectric response in lead zirconate titanate ceramics: The role of ferroelectric domain wall pinning effects

Temperature dependent dielectric response has been measured in Pb(Zr1-xTix)O-3 ceramics. Samples of different compositions (x=0.40, 0.47, and 0.60), pure and doped with Nb-or Fe, were studied at temperatures between 15 and 700 K and in the frequency range from 100 Hz to 1 MHz. Unexpected dielectric behavior has been found around room temperature. Anomalous temperature dependent permittivity is observed in pure and Fe-doped samples but not in Nb-doped samples. The anomaly appears related to the presence of oxygen vacancies but not on the sample crystallographic phase. The authors suggest that the anomaly may be a manifestation of the domain wall pinning effect. (C) 2007 American Institute of Physics.Peer ReviewedPostprint (published version

Miguel Ángel Soto Arenas (1963-2009)

Bio

Analysis of the power balance In the cells of a multilevel cascaded H-Bridge converter

Multilevel cascaded H-Bridge converters (CHB) have been presented as a good solution for high power applications. In this way, several control and modulation techniques have been proposed for this power converter topology. In this paper the steady state power balance in the cells of the single phase two cell CHB is studied. The capability to be supplied with active power from the grid or to deliver active power to the grid in each cell is analyzed according to the dc-link voltages and the desired ac output voltage value. Limits of the maximum and minimum input active power for stable operation of the CHB are addressed. Simulation results are shown to validate the presented analysis

Assessment of tepojal as a support medium in in vitro germination of Barkeria whartoniana (Orchidaceae) and subcultures of B. uniflora and B. scandens

Objective: We evaluated the use of tepojal as a substitute for bacteriological agar for in vitro culture of three species of Mexican orchids of the genus Barkeria. We had three objectives: (1) evaluate the use of tepojal for the in vitro germination of B. whartoniana seeds; (2) compare the growth and survival of B. uniflora and B. scandens plants in in vitro culture on bacteriological agar and tepojal, and (3) compare the early ex situ survival of the B. uniflora and B. scandens previously cultivated in vitro on bacteriological agar and tepojal. Design/Methodology/Approach: For the growth experiment, 1,050 seedlings of Barkeria scandens and B. uniflora were used. Two types of culture medium were prepared: (1) Liquid with tepojal and 40 % MS medium with dextrose, yeast, coconut water, activated carbon and refined sugar, and (2) solid at 40 %, with the same elements as the liquid one, but with 6 g of bacteriological agar. For the germination experiment of Barkeria whartoniana in tepojal we use seeds from a mature (open) capsule. After disinfection, seeds were sown in tepojal with liquid medium and in a solid (agar) culture using a syringe technique. All the seeds were sown in 100 % p668 MS medium with 100 mL/L of coconut water and 15 g/L of refined sugar and using in both the MS medium. Results: Barkeria uniflora seedlings had a greater growth than in B. scandens regardless of the type of treatment. When comparing within each species, we found that the two treatments (tepojal vs agar) did not produce differences in the growth of the shoot of both species. Roots growth was influenced by both the effect of the species and the treatment, as the longest roots were found in tepojal medium. Seed germination observed in the liquid medium with tepojal was not apparently different from that in agar. In both cases the entire surface of the jar was covered with green protocorms. Findings/Conclusions: Tepojal did function well as a substrate to germinate Barkeria whartoniana, but tests must continue to be carried out to evaluate its effectiveness. As no differences were found for aerial growth between agar and tepojal in Barkeria scandens and Barkeria uniflora, we consider this substrate as a good substitute for agar because it can produce more biomass per gram of culture medium used; therefore, if we consider the costs the use of tepojal is much cheaper and much easier to get

Incidência de comportamentos de bullying e solidão na dieta seguida e na prática de atividade física em alunos do ensino fundamental

Resumen: Actualmente, la alimentación y la actividad física están siendo cada vez temas más alarmantes entre la población ya que una mala práctica de ambos desencadena una variedad de enfermedades, entre ellas la obesidad infantil, lo que, a su vez, se relaciona con conductas de bullying o soledad. Por esta razón, en este estudio en el que participaron 293 escolares de colegios de la provincia de Granada se pretende estudiar la relación entre la alimentación, la actividad física, el bullying y la soledad, así como definir cada uno de ellos. Los instrumentos utilizados han sido un cuestionario ad hoc, destinado a la recogida de variables de índole sociodemográfico, el test KIDMED el cual pretendía recoger los datos relacionados con la alimentación de los discentes y la escala de victimización en la escuela y escala de soledad UCLA, los cuales recogían datos relacionados con la victimización. Finalmente, los resultados muestran que cerca de la pluralidad de los discentes realizan más de tres horas de actividad física semanal, la mayoría de estudiantes necesitan mejorar la dieta seguida, la soledad que mayor puntuación refleja es la de red social y el tipo de victimización que mayores niveles refleja es la verbal.Abstract: Currently, diet and physical activity are becoming increasingly alarming issues among the population because a bad practice of both triggers a variety of diseases, including childhood obesity, which is related to bullying behaviors or loneliness. For this reason, in this study have participated 293 schoolchildren from Granada, it is intended to study the relationship between diet, physical activity, bullying and loneliness, as well as define each of them. The instruments used were an ad hoc questionnaire, aimed at collecting variables of a sociodemographic nature, the KIDMED test which sought to collect data related to the feeding of students and the scale of victimization in school and the UCLA loneliness scale, which collected data related to victimization. Finally, the results show that close to the plurality of students perform more than three hours of physical activity per week, most students need to improve their diet, the loneliness that reflects the highest score is that of the social network and the type of victimization that higher levels reflect is the verbal.Resumo: Atualmente, a alimentação e a atividade física tornam-se questões cada vez mais alarmantes entre a população, uma vez que a má prática de ambas desencadeia uma variedade de doenças, entre elas a obesidade infantil, que, por sua vez, está relacionada a comportamentos de bullying ou solidão. Por isso, neste estudo em que participaram 293 escolares de escolas da província de Granada, pretende-se estudar a relação entre alimentação, actividade física, bullying e solidão, bem como definir cada um deles. Os instrumentos utilizados foram um questionário ad hoc, visando coletar variáveis de natureza sociodemográfica, o teste KIDMED que buscou coletar dados relacionados à alimentação dos alunos e a escala de vitimização na escola e a escala de solidão da UCLA, que coletou dados relativos à vitimização. Por fim, os resultados mostram que perto da pluralidade de alunos realizarem mais de três horas de atividade física por semana, a maioria dos alunos precisa melhorar sua alimentação, a solidão que reflete a maior pontuação é a da rede social e o tipo de vitimização que níveis mais altos refletem é o verbal

Transmission of Beauveria bassiana from male to female Aedes aegypti mosquitoes

<p>Abstract</p> <p>Background</p> <p>Resistance to chemical insecticides plus high morbidity rates have lead to rising interest in fungi as candidates for biocontrol agents of mosquito vectors. In most studies fungal infections have been induced by exposure of mosquitoes to various surfaces treated with conidia. In the present study eight Mexican strains of <it>Beauveria bassiana </it>were assessed against <it>Aedes aegypti </it>by direct exposure of females to 6 × 10⁸conidia ml ^-1on a filter paper, afterwards, the transmission of the least and most virulent isolates was evaluated by mating behavior from virgin, fungus-contaminated male to females, to examine this ethological pattern as a new approach to deliver conidia against the dengue vector.</p> <p>Methods</p> <p>In an exposure chamber with a filter paper impregnated with 6 × 10⁸conidia ml ^-1of the least and most virulent strains of <it>B. bassiana</it>, 6-8 day old males of <it>A. aegypti </it>were exposed for 48 hours, and then transferred individually (each one was a replicate) to another chamber and confined with twenty healthy females of the same age. Clean males were used in controls. Survival, infection by true mating (insemination) or by mating attempts (no insemination) and fecundity were daily registered until the death of last female. Data analysis was conducted with proc glm for unbalanced experiments and means were separated with the Ryan test with SAS.</p> <p>Results</p> <p>All strains were highly virulent with LT₅₀ranging from 2.70 (± 0.29) to 5.33 (± 0.53) days. However the most (Bb-CBG2) and least virulent (Bb-CBG4) isolates were also transmitted by mating behavior; both killed 78-90% of females in 15 days after being confined with males that had previously been exposed for 48 hours to fungi. Of these mortality rates, 23 and 38% respectively, were infections acquired by copulations where insemination occurred. The LT₅₀for sexually-infected females were 7.92 (± 0.46) and 8.82 (± 0.45) days for both strains, while the one in control was 13.92 (± 0.58). Likewise, fecundity decreased by 95% and 60% for both Bb-CBG2 and Bb-CBG4 isolates in comparison with control. The role of mating attempts in this delivery procedure of <it>B. bassiana </it>is discussed.</p> <p>Conclusions</p> <p>This is the first report about transmission of <it>B. bassiana </it>by mating behavior from virgin, fungus-contaminated males to females in <it>A. aegypti</it>. Fungal infections acquired by this route (autodissemination) infringed high mortality rates (90%) in mated or approached females. However, prior to releasing virgin, fungus-contaminated males to spread <it>B. basasiana </it>among females of <it>A. aegypti</it>, this novel alternative needs further investigations.</p

Broadband active differential array for the mid-frequency SKA band

This paper presents the design and characterization process of an active array demonstrator for the mid-frequency range (i.e., 300 MHz-1000 MHz) of the future Square Kilometre Array (SKA) radio telescope. This demonstrator, called FIDA3 (FG-IGN: Fundación General Instituto Geográfico Nacional - Differential Active Antenna Array), is part of the Spanish contribution for the SKA project. The main advantages provided by this design include the use of a dielectric-free structure, and the use of a fully-differential receiver in which differential low-noise amplifiers (LNAs) are directly connected to the balanced tapered-slot antennas (TSAs). First, the radiating structure and the differential low-noise amplifiers were separately designed and measured, obtaining good results (antenna elements with low voltage standing-wave ratios, array scanning capabilities up to 45°, and noise temperatures better than 52 K with low-noise amplifiers at room temperature). The potential problems due to the differential nature of the proposed solution are discussed, so some effective methods to overcome such limitations are proposed. Second, the complete active antenna array receiving system was assembled, and a 1 m2 active antenna array tile was characterized