Self-consistent analysis of electric field effects on Si δ-doped GaAs

We theoretically study the subband structure of single Si delta -doped GaAs inserted in a quantum well and subject to an electric field applied along the growth direction. We use an efficient self-consistent procedure to solve simultaneously the Schrodinger and Poisson equations for different values of electric field and temperature. We thus find the confining potential, the subband energies and their corresponding envelope functions, the subband occupations, and the oscillator strength of intersubband transitions. Opposite to what is usually the case when dealing with the quantum-confined Stark effect in ordinary quantum wells, we observe an abrupt drop of the energy levels whenever the external field reaches a certain value. This critical value of the field is seen to depend only slightly on temperature. The rapid change in the energy levels is accompanied by the appearance of a secondary well in the confining potential and a strong decrease of the oscillator strength between the two lowest subbands. These results open the possibility to design devices for use as optical filters controlled by an applied electric field.Publicad

Small-Scale Abiotic Factors Influencing the Spatial Distribution of Phytophthora cinnamomi under Declining Quercus ilex Trees

Phytophthora root rot is considered one of the main factors associated with holm oak (Quercus ilex L.) mortality. The effectiveness and accuracy of soilborne pathogen and management could be influenced by soil spatial heterogeneity. This factor is of special relevance in many afforestation of southwestern Spain, which were carried out without phytosanitary control of the nursery seedlings. We selected a study area located in a 15 year-old afforestation of Q. ilex, known to be infested by Phytophthora cinnamomi Rands. Soil samples (ntotal = 132) were taken systematically from a grid under 4 trees, and analysed to quantify 12 variables, the colony forming units (cfu) of P. cinnamomi plus 11 physical and chemical soil properties. The combined analysis of all variables was performed with linear mixed models (GLMM), and the spatial patterns of cfu were characterised using an aggregation index (Ia) and a clustering index (ν) by SADIE. Cfu values ranged from 0 to 211 cfu g−1, and the GLMM built with the variables silt, P, K and soil moisture explained the cfu distribution to the greatest extent. The spatial analysis showed that 9 of the 12 variables presented spatial aggregation (Ia > 1), and the clustering of local patches (νi≥1.5) for organic matter, silt, and Ca. The spatial patterns of the P. cinnamomi cfu under planted holm oak trees are related to edaphic variables and canopy cover. Small-scale spatial analysis of microsite variability can predict which areas surrounding trees can influence lower oomycetes cfu availability

Evenings of Teaching and Parish: The indoctrination of girls by means of the magazines Bazar and Tin Tan during Franco's dictatorship in Spain (1947-1957)

The Feminine Section and Catholic Action carried out similar work related to training as well as social and health care. The former was more political in its focus while the latter was more religious. From the very beginning both organizations created their own periodic publications, which were either internal if aimed at leaders and active members and external, if they were to be read by the general public. While the former served to train and define its own members, the newspapers and magazines for the masses were used to project their political or religious ideals and to try to recruit new followers. We will concentrate on two of them which were aimed at a young female readership: Bazar, which was published by the Feminine Section and Tin Tan, which was published by Catholic Action.La presencia de la mujer fuera de la esfera privada durante el primer franquismo se redujo a dos entornos concretos: la militancia en la Sección Femenina y la pertenencia a asociaciones de signo religioso, dentro de las cuales destacó la rama femenina de Acción Católica. Sección Femenina y Acción Católica realizaron labores similares relacionadas con la formación y la asistencia socio-sanitaria, predominando el componente político en la primera y el religioso en la segunda. Desde el primer momento, ambas organizaciones generaron sus propias publicaciones periódicas pudiendo ser internas, si se dirigían a los dirigentes y militantes, y externas o dedicadas al público general. Mientras que las primeras sirvieron para formar y encuadrar a sus propios miembros, los periódicos o revistas de masas se destinaron a proyectar sus ideales políticos o religiosos e intentar captar a nuevos seguidores. Nosotros nos fijaremos en dos de ellas destinadas al público infantil femenino: Bazar, publicada por Sección Femenina, y Tin Tan por Acción Católica

Stability of the personal relationship networks in a longitudinal study of middle school students

The personal network of relationships is structured in circles of friendships, that go from the most intense relationships to the least intense ones. While this is a well established result, little is known about the stability of those circles and their evolution in time. To shed light on this issue, we study the temporal evolution of friendships among teenagers during two consecutive academic years by means of a survey administered on five occasions. We show that the first two circles, best friends and friends, can be clearly observed in the survey but also that being in one or the other leads to more or less stable relationships. We find that being in the same class is one of the key drivers of friendship evolution. We also observe an almost constant degree of reciprocity in the relationships, around 60%, a percentage influenced both by being in the same class and by gender homophily. Not only do our results confirm the mounting evidence supporting the circle structure of human social networks, but they also show that these structures persist in time despite the turnover of individual relationships -- a fact that may prove particularly useful for understanding the social environment in middle schools.Comment: 10 pages, 7 figures, requires wlscirep.cls, jabbrv.sty, jabbrv-ltwa-all.ldf, and jabbrv-ltwa-en.ldf (included

A unilateral robotic knee exoskeleton to assess the role of natural gait assistance in hemiparetic patients.

Background: Hemiparetic gait is characterized by strong asymmetries that can severely affect the quality of life of stroke survivors. This type of asymmetry is due to motor deficits in the paretic leg and the resulting compensations in the nonparetic limb. In this study, we aimed to evaluate the effect of actively promoting gait symmetry in hemiparetic patients by assessing the behavior of both paretic and nonparetic lower limbs. This paper introduces the design and validation of the REFLEX prototype, a unilateral active knee–ankle–foot orthosis designed and developed to naturally assist the paretic limbs of hemiparetic patients during gait. Methods: REFLEX uses an adaptive frequency oscillator to estimate the continuous gait phase of the nonparetic limb. Based on this estimation, the device synchronically assists the paretic leg following two different control strategies: (1) replicating the movement of the nonparetic leg or (2) inducing a healthy gait pattern for the paretic leg. Technical validation of the system was implemented on three healthy subjects, while the effect of the generated assistance was assessed in three stroke patients. The effects of this assistance were evaluated in terms of interlimb symmetry with respect to spatiotemporal gait parameters such as step length or time, as well as the similarity between the joint’s motion in both legs. Results: Preliminary results proved the feasibility of the REFLEX prototype to assist gait by reinforcing symmetry. They also pointed out that the assistance of the paretic leg resulted in a decrease in the compensatory strategies developed by the nonparetic limb to achieve a functional gait. Notably, better results were attained when the assistance was provided according to a standard healthy pattern, which initially might suppose a lower symmetry but enabled a healthier evolution of the motion of the nonparetic limb. Conclusions: This work presents the preliminary validation of the REFLEX prototype, a unilateral knee exoskeleton for gait assistance in hemiparetic patients. The experimental results indicate that assisting the paretic leg of a hemiparetic patient based on the movement of their nonparetic leg is a valuable strategy for reducing the compensatory mechanisms developed by the nonparetic limb.post-print6406 K

Transcranial Direct Current Stimulation (tDCS) Combined with Therapeutic Exercise and Cognitive Rehabilitation to Treat a Case of Burning Mouth Syndrome (BMS) Related Pain.

Burning Mouth Syndrome (BMS) is a multifactorial, chronic pain condition with neuropathic and psychogenic mechanisms. Cortical activation as well as sustained attention and executive functions have proven to be affected by chronic pain. The main objectives of this work were to test the efficacy of a multidimensional personalized pain treatment protocol and to investigate if the effects are based on psychophysical pain processing changes or cognitive effects. A 74-year-old female with 2 years of BMS received 10 sessions of a combined protocol of anodal left dorsolateral prefrontal cortex tDCS, cognitive therapy, and therapeutic exercise. The subjective perception of pain decreased by 47% after treatment but returned to the baseline at 45 days. No changes were found in objective pain measurements apart from a transient worsening of conditioned pain modulation. A large effect size was found in all functional scales, processing speed and executive control as well as sustained attention that persisted during follow-up. No changes in anxiety and depression were found. A multimodal therapeutic approach combining TDCS, cognitive rehabilitation and therapeutic exercise produces improved quality of life, disability and pain perception correlated with improvements in processing speed, executive control and sustained attention but independent of changes in psychophysical pain processing.post-print475 K

New Approaches Based on Non-Invasive Brain Stimulation and Mental Representation Techniques Targeting Pain in Parkinson’s Disease Patients: Two Study Protocols for Two Randomized Controlled Trials.

Pain is an under-reported but prevalent symptom in Parkinson’s Disease (PD), impacting patients’ quality of life. Both pain and PD conditions cause cortical excitability reduction and non-invasive brain stimulation. Mental representation techniques are thought to be able to counteract it, also resulting effectively in chronic pain conditions. We aim to conduct two independent studies in order to evaluate the efficacy of transcranial direct current stimulation (tDCS) and mental representation protocol in the management of pain in PD patients during the ON state: (1) tDCS over the Primary Motor Cortex (M1); and (2) Action Observation (AO) and Motor Imagery (MI) training through a Brain-Computer Interface (BCI) using Virtual Reality (AO + MI-BCI). Both studies will include 32 subjects in a longitudinal prospective parallel randomized controlled trial design under different blinding conditions. The main outcomes will be score changes in King’s Parkinson’s Disease Pain Scale, Brief Pain Inventory, Temporal Summation, Conditioned Pain Modulation, and Pain Pressure Threshold. Assessment will be performed pre-intervention, post-intervention, and 15 days post-intervention, in both ON and OFF states.post-print453 K

Clinical Effects of Immersive Multimodal BCI-VR Training after Bilateral Neuromodulation with rTMS on Upper Limb Motor Recovery after Stroke. A Study Protocol for a Randomized Controlled Trial.

Background and Objectives: The motor sequelae after a stroke are frequently persistent and cause a high degree of disability. Cortical ischemic or hemorrhagic strokes affecting the corticospinal pathways are known to cause a reduction of cortical excitability in the lesioned area not only for the local connectivity impairment but also due to a contralateral hemisphere inhibitory action. Non-invasive brain stimulation using high frequency repetitive magnetic transcranial stimulation (rTMS) over the lesioned hemisphere and contralateral cortical inhibition using low-frequency rTMS have been shown to increase the excitability of the lesioned hemisphere. Mental representation techniques, neurofeedback, and virtual reality have also been shown to increase cortical excitability and complement conventional rehabilitation. Materials and Methods: We aim to carry out a single-blind, randomized, controlled trial aiming to study the efficacy of immersive multimodal Brain–Computer Interfacing-Virtual Reality (BCI-VR) training after bilateral neuromodulation with rTMS on upper limb motor recovery after subacute stroke (>3 months) compared to neuromodulation combined with conventional motor imagery tasks. This study will include 42 subjects in a randomized controlled trial design. The main expected outcomes are changes in the Motricity Index of the Arm (MI), dynamometry of the upper limb, score according to Fugl-Meyer for upper limb (FMA-UE), and changes in the Stroke Impact Scale (SIS). The evaluation will be carried out before the intervention, after each intervention and 15 days after the last session. Conclusions: This trial will show the additive value of VR immersive motor imagery as an adjuvant therapy combined with a known effective neuromodulation approach opening new perspectives for clinical rehabilitation protocols.post-print966 K

Las Ayudas Hipermediales Dinámicas (AHD) en los Proyectos de Aula /

Las Ayudas Hipermediales Dinámicas (AHD) en los Proyectos de Aula, es una investigación que tuvo como objetivo caracterizar las prácticas de enseñanza y aprendizaje de los maestros y maestras de las instituciones educativas beneficiadas por Computadores para Educar 2012-2014 al implementar proyectos de aula en TIC; una vez que se ha podido identificar que a pesar de que las instituciones educativas reciben dotación de equipos computacionales, las prácticas de los maestros no reflejan mejoras en los procesos de aula. Es una investigación cualitativa, de corte interpretativo, donde se trabaja con un diseño de estudio de caso múltiple, en sedes seleccionadas de los departamentos de Caldas, Quindío, Norte del Valle y Risaralda. El artículo se encuentra estructurado en los siguientes apartes: Fundamento pedagógico de una AHD, en la interactividad está el cambio en los procesos de aula, el Aprendizaje basado en proyectos, metodología de la investigación, discusión enmarcada en: objetivos, pregunta, secuencia didáctica y la evaluación con AHD. Para finalizar, aparecen las conclusiones, de las cuales se resaltan: Las AHD se sustentan en acciones de aula con TIC las cuales posibilitan el desarrollo y fortalecimiento de los mecanismos de influencia educativa. Las relaciones entre los tres elementos del triángulo didáctico: maestro, estudiante y saber, se ven favorecidas por el uso pedagógico de las AHD. La organización de la actividad conjunta mediada con AHD, está prevista en el diseño tecnopedagógico, la cual se enfatiza en la construcción de nuevos conocimientos a partir de los intercambios colaborativos entre estudiantes y maestro.Universidad Autónoma del Caribe

Validation of Cognitive Rehabilitation as a Balance Rehabilitation Strategy in Patients with Parkinson’s Disease: Study Protocol for a Randomized Controlled Trial.

Background: Parkinson’s disease (PD) is the second most common neurodegenerative disorder. This disease is characterized by motor symptoms, such as bradykinesia, tremor, and rigidity. Although balance impairment is characteristic of advanced stages, it can be present with less intensity since the beginning of the disease. Approximately 60% of PD patients fall once a year and 40% recurrently. On the other hand, cognitive symptoms affect up to 20% of patients with PD in early stages and can even precede the onset of motor symptoms. There are cognitive requirements for balance and can be challenged when attention is diverted or reduced, linking a worse balance and a higher probability of falls with a slower cognitive processing speed and attentional problems. Cognitive rehabilitation of attention and processing speed can lead to an improvement in postural stability in patients with Parkinson’s. Methods: We present a parallel and controlled randomized clinical trial (RCT) to assess the impact on balance of a protocol based on cognitive rehabilitation focused on sustained attention through the NeuronUP platform (Neuronup SI, La Rioja, Spain) in patients with PD. For 4 weeks, patients in the experimental group will receive cognitive therapy three days a week while the control group will not receive any therapy. The protocol has been registered at trials.gov NCT04730466. Conclusions: Cognitive therapy efficacy on balance improvement may open the possibility of new rehabilitation strategies for prevention of falls in PD, reducing morbidity, and saving costs to the health care system.post-print1014 K