2,123 research outputs found

    103 Atypical Progressive Bulbar Palsy presenting with Dropped Head

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    Introduction: Typical amyotrophic lateral sclerosis (ALS) presents on neurological examination with specific signs of upper and lower motor neuron degeneration (Brooks et al, 1995), which can account for 85% of patients with ALS (Turner and Talbot, 2013). There are different types of clinical presentations, including progressive bulbar palsy (PBP), Limb-onset ALS, progressive muscular atrophy (PMA) and upper motor neuron (UMN) predominant ALS. PBP has mainly brainstem signs. There are a few case reports of dropped head syndrome in ALS, mainly in patients with the limb involvement variant. Methods: Case report Results: A 56 year old right-handed male, presented to the clinic with four months of dysphagia to liquids and solids, neck pain and progressive neck weakness causing constant drop head. No dysarthria or other neurological symptoms, no dyspnea. Neurological examination: Cranial Nerve (CN) CN XII: Nasal voice, bilateral atrophy of the tongue with tremor and fasciculations. Motor: Diffuse atrophy and decreased tone of the sternocleidomastoid and trapezii bilaterally, strength: 2/5 in neck flexors and extensors. Sensory: Hypoesthesia of the tongue. The rest of his neurological examination was normal. Labs: Routine blood work, thyroid function tests, collagen vascular work-up, and protein electrophoresis were normal. Creatine Phosphokinase (CPK) and Acetylcholine Receptor Antibodies (AChR Ab) were negative. Brain and Spinal Cord MRI: Showed mild brainstem, cerebellar and cervical spinal atrophy. Conclusions: Patients with ALS initially present with symptoms localized to the limbs or bulbar muscles. A very small percentage 1-2% of ALS patients had neck muscle weakness with head drop (Jokelainen et al, 1977; Gourie-Devi et al, 2003). However, in all the previously reported cases, the patients had limb involvement at the time of presentation which was absent in this case, and the head drop occurred after the onset of symptoms (Lange et al, 1986; Katz et al; 1996). Dropped head syndrome can be seen in inflammatory myopathies, myasthenia gravis, facioscapulohumeral muscular dystrophy, spinal muscular atrophy, nemaline myopathy and carnitine deficiency (Umapathy et al, 2003) but ALS should also be considered in patients with atypical presentations

    Magnetic Field scaling of Relaxation curves in Small Particle Systems

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    We study the effects of the magnetic field on the relaxation of the magnetization of small monodomain non-interacting particles with random orientations and distribution of anisotropy constants. Starting from a master equation, we build up an expression for the time dependence of the magnetization which takes into account thermal activation only over barriers separating energy minima, which, in our model, can be computed exactly from analytical expressions. Numerical calculations of the relaxation curves for different distribution widths, and under different magnetic fields H and temperatures T, have been performed. We show how a \svar scaling of the curves, at different T and for a given H, can be carried out after proper normalization of the data to the equilibrium magnetization. The resulting master curves are shown to be closely related to what we call effective energy barrier distributions, which, in our model, can be computed exactly from analytical expressions. The concept of effective distribution serves us as a basis for finding a scaling variable to scale relaxation curves at different H and a given T, thus showing that the field dependence of energy barriers can be also extracted from relaxation measurements.Comment: 12 pages, 9 figures, submitted to Phys. Rev.

    Entropy and equilibrium state of free market models

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    Many recent models of trade dynamics use the simple idea of wealth exchanges among economic agents in order to obtain a stable or equilibrium distribution of wealth among the agents. In particular, a plain analogy compares the wealth in a society with the energy in a physical system, and the trade between agents to the energy exchange between molecules during collisions. In physical systems, the energy exchange among molecules leads to a state of equipartition of the energy and to an equilibrium situation where the entropy is a maximum. On the other hand, in the majority of exchange models, the system converges to a very unequal condensed state, where one or a few agents concentrate all the wealth of the society while the wide majority of agents shares zero or almost zero fraction of the wealth. So, in those economic systems a minimum entropy state is attained. We propose here an analytical model where we investigate the effects of a particular class of economic exchanges that minimize the entropy. By solving the model we discuss the conditions that can drive the system to a state of minimum entropy, as well as the mechanisms to recover a kind of equipartition of wealth

    Experiencia en el desarrollo de una herramienta para la enseñanza de comunicaciones digitales en carreras de Informática

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    Este trabajo presenta una herramienta de aprendizaje asistido por banco de pruebas formada por tres elementos: plataforma hardware, arquitectura de software multicapa y herramienta gráfica (gtTAL). Para el desarrollo de la herramienta se ha optado por una arquitectura multicapa donde el nivel más alto es una interfaz gráfica que permite la interacción con la plataforma sin necesidad de tener conocimientos de programación de hardware a bajo nivel. Por tanto, los estudiantes pueden testear algoritmos fácilmente sin desarrollar un nuevo programa desde cero, reduciendo significativamente el tiempo empleado para las tareas de implementación y optimización.Peer Reviewe

    A novel mobile application to determine mandibular and tongue laterality discrimination in women with chronic temporomandibular disorder

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    Chronic pain from temporomandibular disorders (TMDs) is caused by a somatosensory disturbance due to sustained activation of central nervous system nociceptive pathways, which can induce changes in neuroplasticity in the thalamus, basal ganglia and limbic system, as well as disturbances in the somatosensory, prefrontal and orbitofrontal cortex and cognitive impairment. The main objective of this study was to determine the discrimination capacity of mandibular and tongue laterality between women with chronic TMDs and asymptomatic women. This descriptive-comparative study examined 2 groups with a total of 30 women. All participants were between the ages of 23 and 66 years and were assigned to the chronic TMD group or the asymptomatic group according to the inclusion criteria. We employed a mobile application developed specifically for this study to measure the accuracy and reaction time (RT) of mandibular and tongue laterality discrimination. The chronic TMD group had a lower success rate in laterality discrimination (mean mandibular accuracy of 40% and mean tongue accuracy of 67%) than the asymptomatic group (mean mandibular accuracy of 61% and mean tongue accuracy of 90%). These results showed statistically significant differences between the groups for mandibular laterality discrimination (d, 1.14; p<0.01) and tongue laterality discrimination (d, 0.79; p=0.03). The asymptomatic group had faster RTs than the chronic TMD group. The data revealed statistically significant differences for the right mandibular RT (d, 0.89; p=0.02) and right tongue RT (d, 0.83; p=0.03). However, there were no significant differences for left mandibular and left tongue RT. We found that the women with chronic TMDs had a lower success rate and slower RTs in the discrimination of mandibular laterality when compared with the asymptomatic women

    Polarization independent 2×2 multimode interference coupler with bricked subwavelength metamaterial

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    The silicon-on-insulator (SOI) platform enables high integration density in photonic integrated circuits while maintaining compatibility with CMOS fabrication processes. Nevertheless, its inherently high modal birefringence hinders the development of polarization-insensitive devices. The dispersion and anisotropy engineering leveraging subwavelength grating (SWG) metamaterials makes possible the development of polarization agnostic waveguide components. In this work we build upon the bricked SWG metamaterial nanostructures to design a polarization independent 2×2 multimode interference (MMI) coupler for the 220 nm SOI platform, operating in the telecom O-band. The designed device exhibits a 160 nm bandwidth with excess loss, polarization dependent loss and imbalance below 1 dB and phase error lower than 5°.Ministerio de Economía y Competitividad (PID2019-106747RB-I00), Junta de Andalucía (P18-RT-1453, UMA20-FEDERJA-158), Ministerio de Ciencia Innovación y Universidades (FPU16/06762, FPU19/02408) and Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech

    Polarization-insensitive multimode interference coupler based on bricked subwavelength gratings

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    The recently proposed bricked patterning enables enhanced performance in integrated photonics devices based on subwavelength gratings, including polarization insensitivity. We report on the design of a polarization-agnostic 2×2 multimode interference coupler for the 220 nm silicon-on-insulator platform using the bricked SWG metamaterial, operating in telecom O-band.We acknowledge funding from Ministerio de Economía y Competitividad (PID2019-106747RB-I00), Junta de Andalucía (P18-RT-1453, UMA-FEDERJA-158), Ministerio de Ciencia Innovación y Universidades (FPU16/06762, FPU19/02408). Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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