HIV/AIDS Policy in Nicaragua: A Civil Society Perspective

Examines Nicaragua's HIV/AIDS epidemic in the context of socioeconomic, political, legal, and societal factors and the state of the health care system. Makes recommendations for improving policy implementation, monitoring, treatment, and legal protection

The effect of short-term endurance and strength training on motor unit conduction velocity

AIM: The aim of this study was to investigate the effect of strength and endurance training on the conduction velocity of vastus medialis obliquus and lateralis single motor units during voluntary sustained knee extensions. METHODS: Seventeen sedentary healthy men (age, mean ± SD, 26.3 ± 3.9 yr) were randomly assigned to one of 2 groups: strength training (ST, n= 8) or endurance training (ET, n= 9). Conventional endurance and strength training was performed three days per week, over a period of 6 weeks. Motor unit conduction velocity (MUCV), maximum voluntary force (MVC) and time-to-task failure at 30% MVC of the knee extensors were measured before and immediately following training. To assess MUCV, multi-channel surface and intramuscular EMG signals were concurrently recorded from the vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during 60-s isometric knee extensions at 10% and 30% of MVC. RESULTS: After 6 weeks of training, MVC increased in the ST group (16.7 ± 7.4 %; P < 0.05) whereas time to task failure was prolonged in the ET group (33.3 ± 14.2 %; P < 0.05). Both training programs induced an increase in motor unit conduction velocity at both 10% and 30% MVC (P < 0.01). Furthermore after both training programs, the reduction in MUCV over time during the sustained contractions occurred at slower rates compared to baseline (P < 0.01). CONCLUSION: These results indicate that short-term endurance and strength training induce similar alterations of the electrophysiological membrane properties of the muscle fiber and in their changes during sustained contractionsGrant SFRH/BD/31796/2006 from Fundação para a Ciência e a Tecnologia (FCT) of Portuga

Adjustments in motor unit properties during fatiguing contractions after training

The objective of the study was to investigate the effect of strength and endurance training on muscle fiber membrane properties and discharge rates of low-threshold motor units of the vasti muscles during fatiguing contractions. Methods: Twenty-five sedentary healthy men (age (mean T SD) = 26.3 T 3.9 yr) were randomly assigned to one of three groups: strength training, endurance training, or a control group. Conventional endurance and strength training was performed 3 dIwkj1, during a period of 6 wk. Motor unit conduction velocity and EMG amplitude of the vastus medialis obliquus and lateralis muscles and biceps femoris were measured during sustained isometric knee extensions at 10% and 30% of the maximum voluntary contraction before and immediately after training. Results: After 6 wk of training, the reduction in motor unit conduction velocity during the sustained contractions at 30% of the maximum voluntary force occurred at slower rates compared with baseline (P G 0.05). However, the rate of decrease was lower after endurance training compared with strength training (P G 0.01). For all groups, motor unit discharge rates declined during the sustained contraction (P G 0.001), and their trend was not altered by training. In addition, the biceps femoris–vasti coactivation ratio declined after the endurance training. Conclusions: Short-term strength and endurance training induces alterations of the electrophysiological membrane properties of the muscle fiber. In particular, endurance training lowers the rate of decline of motor unit conduction velocity during sustained contractions more than strength trainin

Changes in H reflex and V wave following short-term endurance and strength training

This study examined the effects of 3 wk of either endurance or strength training on plasticity of the neural mechanisms involved in the soleus H reflex and V wave. Twenty-five sedentary healthy subjects were randomized into an endurance group (n 13) or strength group (n 12). Evoked V-wave, H-reflex, and M-wave recruitment curves, maximal voluntary contraction (MVC), and time-to-task-failure (isometric contraction at 40% MVC) of the plantar flexors were recorded before and after training. Following strength training, MVC of the plantar flexors increased by 14.4 5.2% in the strength group (P 0.001), whereas time-to-task-failure was prolonged in the endurance group (22.7 17.1%; P 0.05). The V wave-to-maximal M wave (V/Mmax) ratio increased significantly (55.1 28.3%; P 0.001) following strength training, but the maximal H wave-to-maximal M wave (Hmax/Mmax) ratio remained unchanged. Conversely, in the endurance group the V/Mmax ratio was not altered, whereas the Hmax/Mmax ratio increased by 30.8 21.7% (P 0.05). The endurance training group also displayed a reduction in the H-reflex excitability threshold while the H-reflex amplitude on the ascending limb of the recruitment curve increased. Strength training only elicited a significant decrease in H-reflex excitability threshold, while H-reflex amplitudes over the ascending limb remained unchanged. These observations indicate that the H-reflex pathway is strongly involved in the enhanced endurance resistance that occurs following endurance training. On the contrary, the improvements in MVC following strength training are likely attributed to increased descending drive and/or modulation in afferents other than Ia afferents

Kernel density estimation of electromyographic signals and ensemble learning for highly accurate classification of a large set of hand/wrist motions

The performance of myoelectric control highly depends on the features extracted from surface electromyographic (sEMG) signals. We propose three new sEMG features based on the kernel density estimation. The trimmed mean of density (TMD), the entropy of density, and the trimmed mean absolute value of derivative density were computed for each sEMG channel. These features were tested for the classification of single tasks as well as of two tasks concurrently performed. For single tasks, correlation-based feature selection was used, and the features were then classified using linear discriminant analysis (LDA), non-linear support vector machines, and multi-layer perceptron. The eXtreme gradient boosting (XGBoost) classifier was used for the classification of two movements simultaneously performed. The second and third versions of the Ninapro dataset (conventional control) and Ameri’s movement dataset (simultaneous control) were used to test the proposed features. For the Ninapro dataset, the overall accuracy of LDA using the TMD feature was 98.99 ± 1.36% and 92.25 ± 9.48% for able-bodied and amputee subjects, respectively. Using ensemble learning of the three classifiers, the average macro and micro-F-score, macro recall, and precision on the validation sets were 98.23 ± 2.02, 98.32 ± 1.93, 98.32 ± 1.93, and 98.88 ± 1.31%, respectively, for the intact subjects. The movement misclassification percentage was 1.75 ± 1.73 and 3.44 ± 2.23 for the intact subjects and amputees. The proposed features were significantly correlated with the movement classes [Generalized Linear Model (GLM); P-value < 0.05]. An accurate online implementation of the proposed algorithm was also presented. For the simultaneous control, the overall accuracy was 99.71 ± 0.08 and 97.85 ± 0.10 for the XGBoost and LDA classifiers, respectively. The proposed features are thus promising for conventional and simultaneous myoelectric control.Peer ReviewedPostprint (published version

Detection of multiple innervation zones from multi-channel surface EMG recordings with low signal-to-noise ratio using graph-cut segmentation

Knowledge of the location of muscle Innervation Zones (IZs) is important in many applications, e.g. for minimizing the quantity of injected botulinum toxin for the treatment of spasticity or for deciding on the type of episiotomy during child delivery. Surface EMG (sEMG) can be noninvasively recorded to assess physiological and morphological characteristics of contracting muscles. However, it is not often possible to record signals of high quality. Moreover, muscles could have multiple IZs, which should all be identified. We designed a fully-automatic algorithm based on the enhanced image Graph-Cut segmentation and morphological image processing methods to identify up to five IZs in 60-ms intervals of very-low to moderate quality sEMG signal detected with multi-channel electrodes (20 bipolar channels with Inter Electrode Distance (IED) of 5 mm). An anisotropic multilayered cylinder model was used to simulate 750 sEMG signals with signal-to-noise ratio ranging from -5 to 15 dB (using Gaussian noise) and in each 60-ms signal frame, 1 to 5 IZs were included. The micro- and macro- averaged performance indices were then reported for the proposed IZ detection algorithm. In the micro-averaging procedure, the number of True Positives, False Positives and False Negatives in each frame were summed up to generate cumulative measures. In the macro-averaging, on the other hand, precision and recall were calculated for each frame and their averages are used to determine F1-score. Overall, the micro (macro)-averaged sensitivity, precision and F1-score of the algorithm for IZ channel identification were 82.7% (87.5%), 92.9% (94.0%) and 87.5% (90.6%), respectively. For the correctly identified IZ locations, the average bias error was of 0.02±0.10 IED ratio. Also, the average absolute conduction velocity estimation error was 0.41±0.40 m/s for such frames. The sensitivity analysis including increasing IED and reducing interpolation coefficient for time samples was performed. Meanwhile, the effect of adding power-line interference and using other image interpolation methods on the deterioration of the performance of the proposed algorithm was investigated. The average running time of the proposed algorithm on each 60-ms sEMG frame was 25.5±8.9 (s) on an Intel dual-core 1.83 GHz CPU with 2 GB of RAM. The proposed algorithm correctly and precisely identified multiple IZs in each signal epoch in a wide range of signal quality and is thus a promising new offline tool for electrophysiological studies.The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the Seventh Framework Programme of the European Union (FP7/2007-2013) under REA grant agreement no. 600388 (TECNIOspring programme), from the Agency for Business Competitiveness of the Government of Catalonia, ACCIÓ, and from Spanish Ministry of Economy and Competitiveness- Spain (project DPI2014-59049-R).Peer ReviewedPostprint (published version

An Accurate and Real-time Method for Resolving Superimposed Action Potentials in MultiUnit Recordings

Objective: Spike sorting of muscular and neural recordings requires separating action potentials that overlap in time (superimposed action potentials (APs)). We propose a new algorithm for resolving superimposed action potentials, and we test it on intramuscular EMG (iEMG) and intracortical recordings. Methods: Discrete-time shifts of the involved APs are first selected based on a heuristic extension of the peel-off algorithm. Then, the time shifts that provide the minimal residual Euclidean norm are identified (Discrete Brute force Correlation (DBC)). The optimal continuous-time shifts are then estimated (High-Resolution BC (HRBC)). In Fusion HRBC (FHRBC), two other cost functions are used. A parallel implementation of the DBC and HRBC algorithms was developed. The performance of the algorithms was assessed on 11,000 simulated iEMG and 14,000 neural recording superpositions, including two to eight APs, and eight experimental iEMG signals containing four to eleven active motor units. The performance of the proposed algorithms was compared with that of the Branch-and-Bound (BB) algorithm using the Rank-Product (RP) method in terms of accuracy and efficiency. Results: The average accuracy of the DBC, HRBC and FHRBC methods on the entire simulated datasets was 92.16\ub117.70, 93.65\ub116.89, and 94.90\ub115.15 (%). The DBC algorithm outperformed the other algorithms based on the RP method. The average accuracy and running time of the DBC algorithm on 10.5 ms superimposed spikes of the experimental signals were 92.1\ub121.7 (%) and 2.3\ub115.3 (ms). Conclusion and Significance: The proposed algorithm is promising for real-time neural decoding, a central problem in neural and muscular decoding and interfacing

Representación en la Enseñanza del Patrimonio: Abordaje conceptual y metodológico aplicado en el Campus de Goiabeiras de la Universidade Federal do Espírito Santo – Brasil

This article presents the results of a conceptual and methodological proposal employed in the “Historical, Artistic and Cultural Heritage” course in the Architecture and Urbanism degree at the Federal University of Espírito Santo (UFES), Brazil. It was motivated by the idea of overcoming the conservation- development dichotomy and the widening of the concept of heritage to include the notion of territorial heritage, which not only identifies heritage at broader geographical scales, but also its procedural logic. One of the problems presented is the segmentation of the heritage-teaching-design thematic triad. To overcome it, and through an empirical- qualitative methodology based on the Italian Territorialist School approach, a proactive participatory experience was created in which students are encouraged to work on representation as a method of recognizing heritage-value architecture and interpreting critical pre-existence at the UFES ́s Goiabeiras Campus. The experience is divided into three stages: a) analysis, through a preliminary inventory, which identifies, classifies and categorizes the campus’ valuable assets; b) synthesis, where the previous maps are compared and layers of territorial heritage (physical, built and anthropic) are identified and serve as a basis for the definition of landscape units, according to which the values and potential resources of the territorial heritage are interpreted diachronically; and c) design experience, based on critical interpretation. This experience results in an awareness of the transformative power of territorial heritage representation, not only as a document, but as an active instrument for interpretation, identification and analysis, which improves integrated design actions.Este artículo muestra los resultados de una propuesta conceptual y metodológica, aplicada en una asignatura académica “Patrimonio histórico, artístico y cultural”, del curso de Arquitectura y Urbanismo de la Universidade Federal do Espírito Santo (UFES), Brasil. Y se enmarca en la idea de la superación de la dicotomía conservación-desarrollo y la ampliación conceptual del patrimonio a la noción de patrimonio territorial, que identifica no solo el patrimonio a escalas geográficas más amplias, sino también su lógica procesal. Uno de los problemas expuestos es la segmentación de la tríada temática Patrimonio-Enseñanza- Proyecto. Para trascenderla, y a través de una metodología empírica-cualitativa, basada en el enfoque de la Escuela Territorialista italiana, se realiza una experiencia de participación proactiva, en la que se alienta a los estudiantes a trabajar en la representación como un método para reconocer la arquitectura con valor del patrimonial e interpretación del área de preexistencia crítica, el Campus Universitario Goiabeiras de la UFES. Se divide en tres etapas: a) análisis, a través de un inventario previo, que identifica y clasifica los bienes de valor del campus; b) síntesis, donde se confrontan los mapeos anteriores y se identifican capas del patrimonio territorial (físico, construido y antrópico), que sirven luego como base para la definición de unidades de paisaje, a partir de las cuales los valores y recursos potenciales del patrimonio territorial se interpretan diacrónicamente; c) experiencia del proyecto, basada en una interpretación crítica. Los resultados de la iniciativa expuesta generan conciencia del poder transformador de la representación del patrimonio territorial, no solo como documento, sino como un instrumento activo de interpretación, reconocimiento y análisis, capaz de optimizar las acciones integradas del proyecto.Esse artigo mostra os resultados de uma proposição conceitual e metodológica, aplicada em disciplina acadêmica, “Patrimônio Histórico, Artístico e Cultural”, do curso de Arquitetura e Urbanismo da Universidade Federal do Espírito Santo (UFES), Brasil. Fomentada pela superação da dicotomia conservação-desenvolvimento e pelo alargamento conceitual do patrimônio à noção de patrimônio territorial, que identifica não apenas um patrimônio em escalas geográficas de maior abrangência, como sua lógica processual. Uma das problemáticas expostas consiste na segmentação da tríade temática Patrimônio-Ensino- Projeto. Para sua superação, e por meio de uma metodologia empírico-qualitativa, embasada na abordagem da Escola Territorialista Italiana, faz-se uma experiência de envolvimento proativo, na qual os discentes são estimulados a trabalhar a representação enquanto método de reconhecimento da arquitetura de valor patrimonial e de interpretação de área de preexistência crítica, o Campus Universitário de Goiabeiras da UFES. Divide-se em três etapas: a) análise, por intermédio de um pré-inventário, onde se identifica, classifica e categoriza os bens de valor do campus; b) síntese, onde os mapeamentos anteriores são postos em confronto e são identificadas camadas do patrimônio territorial (física, construída e antrópica), servindo de base à definição de unidades de paisagem, sob as quais se interpretam diacronicamente os valores e os recursos potenciais do patrimônio territorial; c) experiência projetual, fundamentada a partir de uma interpretação crítica. A experiência resulta na tomada de conciência da potência trnsformadora da reprentação do patrimônio territorial, não apenas enquanto documento, mas instrumento ativo de interpretação, reconhecimento e análise, potencializando ações projetuais integradas

Seasonal variation in blood pressure: what is still missing?

Seasonal variation of blood pressure (BP) is a topic in cardiology that has gained more attention throughout the years. Although it is extensively documented that BP increases in seasons coupled with lower temperatures, there are still many gaps in this knowledge field that need to be explored. Notably, seasonal variation of BP phenotypes, such as masked and white coat hypertension, and the impact of air pollution, latitude, and altitude on seasonal variation of BP are still poorly described in the literature, and the levels of the existing evidence are low. Therefore, further investigations on these topics are needed to provide robust evidence that can be used in clinical practice

Trace Elemental Composition in PM10 and PM2.5 Collected in Cardiff, Wales

A Dichotomous Sampler Model 241 was used to collect PM10 and PM2.5 samples, from midnight to midnight on every other day, from December 2009 to December 2010. Ca, K, Mg, Na, Al, Pb, Cr, Ni, Zn, Cu, Cd, and Fe were determined by Atomic absorption Spectrometer (AAS). The mass concentration ranged from 18.0 to 83.3 μg/m3, with an annual average of 37. 9 μg/m3 for PM10. The mass concentration of PM2.5 ranged from 3.0 to 36.0 μg/m3 with an annual average of 14.1 μg/m. Most of the elements in both PM fractions were abundant in the winter season. A good correlation was observed between PM10 and PM2.5.Enrichment factors (EF) for elements in PM10 and PM2.5 were calculated and indicate that elements from anthropogenic origins such as Zn, Pb, Cu, Cr and Cd were highly enriched with respect to crustal elements Al, Fe and Ca