Evaluation of EMG processing techniques using Information Theory

<p>Abstract</p> <p>Background</p> <p>Electromyographic signals can be used in biomedical engineering and/or rehabilitation field, as potential sources of control for prosthetics and orthotics. In such applications, digital processing techniques are necessary to follow efficient and effectively the changes in the physiological characteristics produced by a muscular contraction. In this paper, two methods based on information theory are proposed to evaluate the processing techniques.</p> <p>Methods</p> <p>These methods determine the amount of information that a processing technique is able to extract from EMG signals. The processing techniques evaluated with these methods were: absolute mean value (AMV), RMS values, variance values (VAR) and difference absolute mean value (DAMV). EMG signals from the middle deltoid during abduction and adduction movement of the arm in the scapular plane was registered, for static and dynamic contractions. The optimal window length (segmentation), abduction and adduction movements and inter-electrode distance were also analyzed.</p> <p>Results</p> <p>Using the optimal segmentation (200 ms and 300 ms in static and dynamic contractions, respectively) the best processing techniques were: RMS, AMV and VAR in static contractions, and only the RMS in dynamic contractions. Using the RMS of EMG signal, variations in the amount of information between the abduction and adduction movements were observed.</p> <p>Conclusions</p> <p>Although the evaluation methods proposed here were applied to standard processing techniques, these methods can also be considered as alternatives tools to evaluate new processing techniques in different areas of electrophysiology.</p

Why the Drug War Endures: Local and Transnational Linkages in the North and Central America Drug Trades

Despite the well-documented human costs of the war on drugs, and the growing evidence of the environmental impacts of illicit economies, the militarized repression of the illicit drug trade remains a central hemispheric security and cooperation strategy in Northern and Central American countries. Through a multi-disciplinary dialogue that combines history, sociology, anthropology, economics, and political science, this Special Issue critically interrogates why despite these failures the war on drug endures. Together, the contributors challenge explanations focused on state absence, weakening of the state, and ungoverned spaces and instead propose a research agenda that sheds light on the long-lasting, structural effects of the capitalistic integration of the region within the economy of illicit drugs. In particular, the Special Issue contributes to three existing and interconnected debates: First: the role of drug economies and illicitness on state formation, social inequalities, and development in Mexico and Central America. Second: the impact of illicit economies on local populations, and the connections between the licit and the illicit, margins and centers, and political orders and violence. Third: the variety of stakeholders that benefit from the war on drugs and that link the United States, Mexico, and Central America in licit and illicit fashions

Distal root curvatures in mandibular molars: analysis using digital panoramic X-rays

Background: The aim of this study was to describe the degree of curvature in distal roots in the first and second permanent mandibular molars in a Chilean patient sample. A cross-sectional descriptive study was conducted in which digital panoramic X-rays were analysed. Materials and methods: Examinations of patients under 18 years, with signs of distortion or alteration in the contrast or the presence of pathologies that affected visualisation of the roots and pulp-chamber floor of the teeth to be analysed were excluded. Using the AutoCad software, an angle was drawn to represent the curve of the root in its different thirds, drawing lines inside the root canal from the pulp-chamber floor to the dental apex. Using the classic definition of dilaceration (root curvature &gt; 90°), its prevalence was established. 412 teeth and roots were analysed, finding a dilaceration prevalence of 0.73% (n = 3). 84.72% of the roots presented some type of curvature. Results: The middle third had the highest percentage of curvatures and the greatest average of angular curvature, whereas the cervical third was the straightest. No significant differences were found between the degree of curvature and the gender of the subjects, except for the apical third of tooth 3.6. The analysis of curvature by root third offers to the clinician a better perspective of the directional change of the roots and does not limit it to just the presence of curves in the apical third. Conclusions: The report of the angular degree of the curvatures, in addition to the prevalence of dilacerations, informs to the clinicians about the likelihood of finding difficulties when treating root canals. (Folia Morphol 2018; 77, 1: 131–137

Concientización a los productores beneficiarios del proyecto sobre medidas y actividades a desarrollar para evitar o mitigar los impactos medioambientales durante la ejecución y vida del proyecto productivo en las veredas La Florida, San Juan, Getzen y Alto Cañada

Fotografias, Imagenes, Graficas, TablasLa evidente destrucción y alteración de los espacios naturales en las partes rurales ha provocado un cambio ambiental que se ve reflejado en la pérdida de biodiversidad, modificación del recurso hídrico y perturbación de bienes y servicios ecosistémicos. Es por ello que a través de la experiencia profesional dirigida desarrollada mediante uno de los proyectos especiales que desarrolla Asociación Agroempresarial de sur occidente del Departamento del Huila “ASOMSURCA” cuyo objetivo es el desarrollo social, económico, político, cultural y ambiental de los territorios del área de influencia, con criterio de competitividad, sostenibilidad y equidad; se implementaron estrategias encaminadas a mitigar la problemática ambiental de cuatro veredas del municipio de La Plata Huila, mediante capacitaciones individuales y grupales inculcando en la comunidad rural la construcción de una conciencia medioambiental responsable y respetuosa con el entorno.The evident destruction and alteration of natural areas in rural parts caused an environmental change that is reflected in the loss of biodiversity, modification of water resources and disruption of ecosystem goods and services. That is why through targeted professional experience developed by one of the special projects aimed ASOMSURCA develops social, economic, political, cultural and environmental development of the territories of the area of influence, with criteria of competitiveness, sustainability and equity; strategies to mitigate environmental problems in four villages in the municipality of La Plata Huila, through individual and group training instilled in the rural community to build a responsible and respectful of the environment were implemented environmental awareness

Prevalence and morphometric analysis of idiopathic osteosclerosis in a Chilean population

Background: The aim of this study was to analyse the prevalence and morpho­metric parameters of idiopathic osteosclerosis (IO) in a Chilean population. IO is an intraosseous growth of compact, benign, unilocular, non-expandable bone that is referred to as an anatomical variation. Materials and methods: A cross-sectional study was performed using 1000 digital panoramic radiographs of adults in which data on the location (maxillary/ mandibular, right/left hemiarcades), shape, position to the dental apex, and the prevalence of IOs were observed in relation to gender and age. The morphometric parameters evaluated were area, height, width, and the linear distances of the IO up to the midline and at the base of the mandible. Results: The overall prevalence was 2.8% (27 individuals), with the majority of cases in women (66.7%) in the second, third, and fifth decades of life, but without significant differences. All cases were present in the mandible (100%), usually in the left hemiarcade (59.3%), molar (48.2%) and premolar (44.4%) regions; at the height of the dental apices (65.5%), with an irregular shape (40.7%) and round (37%). The area of the IOs was 33.9 ± 20.1 mm2, with a height of 7.7 ± ± 3.1 mm, width of 6.6 ± 3.1 mm, and the distance from the IO to the mandible median line was 26.6 ± 10.7 mm and 9.7 ± 3.7 mm to the mandibular base. Conclusions: All the data observed corroborate with previous studies; the IO does not present a large difference in the Chilean population evaluated compared to pre­vious studies carried out in other populations. (Folia Morphol 2018; 77, 2: 272–278

Location and course of the mandibular canal in dentate patients: morphometric study using cone-beam computed tomography

Background: The morphometric characteristics of the mandibular canal (MC) may vary according to the characteristics of the population studied. Correct location of the MC is fundamental for the indication and planning of different dental treatments, and it is therefore essential to have clinical parameters indicating its approximate location. The aim of this study was to describe the location and course of the MC by morphometric relations in the mandibular body, from the mental foramen to distal of the first molar, in dentate adult patients. Materials and methods: We analysed 55 cone-beam computed tomography (CBCT) of male and female patients, aged over 18 years and with fully dentate to the first molar. In each CBCT we selected five coronal sections (A–E) of the mandibular body at different levels using the teeth as references. We determined different morphometric measurements in each section to relate the MC with the corticals of the mandibular body (m1, m2, m3, m4), their orientation to lingual (F) and the thickness of the mandibular corticals (B1, B2 and B3). Results: The distance between the MC and the alveolar crests was greater in males than in females in all the sections. In general, in all the hemiarches, the MC courses away from the vestibular cortical of the mandible (and in some cases significantly towards the lingual cortical) from anterior to posterior in the mandibular body. In the left hemiarch of dentate females the MC describes a descent in the molar zone within the mandibular body. Any intervention in the mandible must be carried out with extreme caution to avoid damaging the vasculo-nervous bundle which passes through the MC. Conclusions: Cone-beam computed tomography is the best tool currently available for the planning and execution of surgical procedures, and is the only tool in clinical use which allows the precise course of the MC to be identified

Bilateral bifid mandibular canal: a case report using cone beam computed tomography

The mandibular canal (MC) originates in the mandibular foramen and runs bilaterally through the mandibular ramus and body, ending in the mental foramen. One of the most common anatomical variations is bifid MC, the configurations of which have been classified into four categories and sub-categories. The prevalence of these variations depends on the imaging method used. Studies carried out in panoramic X-rays and cone beam computed tomography (CBCT) showprevalences varying between 1% and 20%. In this case report we present the finding of a bilateral bifid MC by CBCT examination; we describe its location and morphological characteristics. The variation found was a type 1 bilateral bifid MC, which consists in an accessory canal originating from a single mandibular foramen and extending to the third molar or its immediate surroundings. In this report we discuss the importance of detecting these anatomical variations, as well as their implications in clinical practice