bluuebunny/crossref_metadata_2025 huggingface dataset:
Erradicación de cultivos de uso ilícito: fracaso del plan Colombia y éxito del efecto globo
Authors: Romero Moreno María Fernanda , Silva Serna Juan Sebastián
Published: August 2019

El presente artículo pretende analizar una de las consecuencias de la internacionalización del conflicto social y armado colombiano, el Plan Colombia, y específicamente la erradicación de cultivos de uso ilícito que plantea este, como estrategia de cooperación antinarcóticos entre Estados Unidos y Colombia, que buscaba encontrar una salida política y negociada al conflicto. La erradicación de cultivos de uso ilícito es una de las bases para analizar la eficacia del Plan Colombia, por sus resultados en la disminución de la oferta de droga y la disminución del conflicto colombiano, que finalmente le entrega el éxito verdadero al efecto globo (desplazamiento de cultivos), el cual, no estaba contemplado en los objetivos del Plan Colombia y la erradicación de cultivos de uso ilícito.
Legalización y desarrollo alternativo en la región andina
Authors: Guillou Ronan
Published: August 2019

Con la globalización y desde los años 90 existe un verdadero problema de las drogas. Tanto el consumo, la producción como la circulación de las mismas perturban al Estado en todos los ámbitos: económicos, sociales, políticos y educativos. La region andina, si bien solo se le apuntaba por ser productora, es ahora consumidora y las políticas públicas actuales no parecen ser adecuadas. Por ende Las drogas se deben estudiar sin tabú ni falsos conceptos acerca de ellas y aceptar la realidad para evitar un empeoramiento de la situación. ¿Por qué la prohibición de las drogas? ¿Son malas todas las drogas? ¿La culpa solo la tiene la Region Andina? ¿Pueden las grandes potencias intervenir en los territorios nacionales? La guerra contra las drogas y la prohibición son un fracaso en la region andina, por ello la legalización del mercado aparece entonces como única solución.
Influence of magnetic field strength of hybrid magnet on vibration isolation of quarter car model
Authors: Easu D. , Siddharthan A. , Amrutha R.
Published: August 2019

This work studies the vibration isolation of a single degree of freedom (SDOF) quarter car model under the influence of the magnetic field strength of electromagnet of a hybrid electromagnet (EM) and permanent magnet (PM) combination. Furthermore, the time history plot helps to study the influence of the relative movement of the electromagnet and the permanent magnet on the top plate, base plate, stiffness of the system and damping coefficient. A laboratory scale model of a SDOF quarter car with a hybrid magnet is tested on an open loop type shaker table at different frequencies of base excitation. Data acquisition and analysis have been carried out with the aid of two piezoelectric accelerometers and Lab VIEW software. Also, the theoretical analysis is carried out in MATLAB Simulink. From the experimental and Simulink results, it is found that the repulsive force between the electromagnet and permanent magnet varies the base and top plate amplitude, the stiffness of the system and damping coefficient of the suspension elements.
Active vibration control of rotating beam with moving mass using piezoelectric actuator
Authors: Zhao Liang , Wu Yu-Ping
Published: August 2019

The robotic arm carrying a moving end effector can be modeled as a rotating beam with moving mass. Active vibration control of rotating beam with moving mass using piezoelectric actuator is presented. Simply supported beam and cantilevered beam are considered in this studying. The equations of the system are derived by Lagrange’s equation with the assumed mode method. The linear classical optimal control algorithm with displacement-velocity feedback is used to determine the control voltage. The numerical simulations reveal that the transverse displacements of the beam can be effectively reduced by the actuators. The effect of rotational speed and acceleration to the dynamic responses of the beam are also investigated.
Fault diagnosis method for rolling bearings based on the interval support vector domain description
Authors: Chen Yongqi , Dai Qinge , Chen Yang
Published: August 2019

Aiming at the fault classification problem of the rolling bearing under the uncertain structure parameters work condition, this paper proposes a fault diagnosis method based on the interval support vector domain description (ISVDD). Firstly, intrinsic time scale decomposition is performed for vibration signals of the rolling bearing to get the time-frequency spectrum samples. These samples are divided into a training set and a test set. Then, the training set is used to train the ISVDD. Meanwhile, the dynamic decreasing inertia weight particle swarm optimization is applied to improve the training accuracy of ISVDD model. Finally, the performance of the four interval classifiers is calculated in rolling bearing fault test set. The experimental results show the advantages of the ISVDD model: (1) ISVDD can extend the support vector domain description to solve the uncertain interval rolling bearing fault classification problem effectively; (2) The proposed ISVDD has the highest classification accuracy in four interval classification methods for the different rolling bearing fault types.
An adaptive stochastic resonance method based on multi-agent cuckoo search algorithm for bearing fault detection
Authors: Chi Kuo , Kang Jianshe , Tong Rui , Zhang Xinghui
Published: August 2019

Bearing is widely used in the rotating machinery and prone to failure due to the harsh working environment. The bearing fault-induced impulses are weak because of poor background noise, long vibration transmission path, and slight fault degree. Therefore, the bearing fault detection is difficult. A novel adaptive stochastic resonance method based on multi-agent cuckoo search algorithm for bearing fault detection is proposed. Stochastic resonance (SR) is like a nonlinear filter, which can enhance the weak fault-induced impulses while suppressing the noise. However, the parameters of the nonlinear system exert an influence on the SR effect, and the optimal parameters are difficult to be found. Multi-agent cuckoo search (MACS) algorithm is an excellent heuristic optimization algorithm and can be used to search the parameters of nonlinear system adaptively. Two bearing fault signals are used to validate the effectiveness of our proposed method. Three other adaptive SR methods based on cuckoo search algorithm, particle swarm optimization or genetic algorithm are also used for comparison. The results show that MACS can find the optimal parameters more quickly and more accurately, and our proposed method can enhance the fault-induced impulses efficiently.
Ground vibration propagation and attenuation of vibrating compaction
Authors: Chen Aijun , Cheng Feng , Wu Di , Tang Xianyuan
Published: August 2019

When a high-power vibrating roller compact the subgrade, the vibration wave will quickly propagate along the surface of the subgrade and generate hazards to surrounding environment and structure. To study the vibration propagation rules of the roller, the vibration acceleration of the high-power vibrating roller was measured on the surface of the rock subgrade, coarse-grained soil subgrade and fine-grained soil subgrade. The respective relations between vibration acceleration and the distance from a vibration source in the vertical, horizontal radial and horizontal circumferential direction have been discovered. The research results show that the vibration peak frequency generated by the vibrating roller on the subgrade approximates vibration frequency. The vibration effective influence distance varies from 10m to14m, and the horizontal radial vibration is greater than that of vertical and horizontal circumferential direction. The vibration of the rock subgrade attenuates the most slowly and propagates the most remotely.
Success Rates of Clomiphene Citrate and Recombinant Gonadotropin Cycles: A Single-Center Experience
Authors: Gurlek Beril , Batioglu Ali Sertac , Kanat-Pektas Mine , Kale Ibrahim , Onal Ozgur , Yilmaz-Karakas Nafiye
Published: August 2019

Objective: This aim of this study is to assess the ovulation induction cycles based on clomiphene citrate and gonadotropin administration and specify the factors associated with successful outcomes. Study Design: This is a prospective study of 631 patients who underwent 917 ovulation induction cycles. While clomiphene citrate was used in 680 cycles (74.2%) and recombinant follicle-stimulating hormone was administered in 237 cycles (25.8%). Results: A total of 153 pregnancies were achieved in 917 ovulation induction cycles, indicating a clinical pregnancy rate of 16.7%. The ovulation induction cycles which ended up with clinical pregnancy had a significantly lower frequency of smoking (p=0.005), shorter infertility duration (p=0.001), higher basal luteinizing hormone (p=0.021) and lower basal progesterone (p=0.008) than unsuccessful cycles. The clomiphene citrate cycles which ended up with clinical pregnancy had a significantly lower frequency of smoking (p=0.011), shorter infertility duration (p=0.001) and lower basal progesterone (p=0.013) than the unsuccessful cycles. The recombinant follicle-stimulating hormone cycles which ended up with clinical pregnancy had a significantly higher basal luteinizing hormone (p=0.008) than the unsuccessful cycles. Basal luteinizing hormone and progesterone concentrations could significantly distinguish the patients who were able to conceive in ovulation induction cycles (p=0.021 and p=0.008, respectively).Conclusions: Smoking, longer duration of infertility, and elevated basal progesterone are poor prognostic factors for clinical pregnancy in clomiphene citrate and recombinant follicle-stimulating hormone cycles.
Tumor venéreo transmisible (TVT) de localización extragenital
Authors: Martínez Mastoby M. , Ballut Juan C. , Cardona José A.
Published: August 2019

En este reporte se documenta un caso clínico de tumor venéreo transmisible (TVT) de localización cutánea en un canino femenino virgen.
Restricción del amamantamiento en vacas del sistema cría libre
Authors: Prieto M Esperanza , González T Marco , Espitia P Amado
Published: August 2019

Con el fin de aumentar la tasa de preñez, la cual se encontraba disminuida por la incidencia de anestro postparto prolongado, en la finca Andalucía, se aplicó la tecnología «restricción del amamantamiento a 30 minutos cada día». Se tomaron 38 vacas que tenían más de un mes de paridas, que no se habían observado en calor y que a la palpación rectal se encontraron vacías. Se conformaron 2 grupos de vacas homogéneos en cuanto a números de partos y días postparto, uno que se cometió a restricción del amamantamiento y otro que sirvió de grupo control. Las crías del grupo sometido a restricción del amamantamiento solo mamaron durante 30 minutos cada día, el resto del tiempo se mantuvieron en pastoreo separadas de sus madres, y se les ofreció adicionalmente un suplemento alimenticio. Este manejo se mantuvo hasta cuando la vaca presentó calor. Las crías del grupo control permanecieron con su madre las 24 horas del día. Se realizó palpación rectal al inicio y cada 3 meses. Durante el tiempo que se aplicó la tecnología se registraron las siguientes variables: porcentaje de preñez, días abiertos, peso al ternero al inicio de la restricción y al destete, costo de la tecnología. Con la aplicación de la restricción del amamantamiento a 30 minutos cada día, se aumentó el porcentaje de preñez en 32% y se redujeron los días abiertos y días partos al primer calor en 61 y 41 días respectivamente. El peso de los terneros al destete fue menor en 20Kg para los terneros sometidos a restricción, debido posiblemente al alto estado de enmalezamiento de los potreros (>40%), ocasionado por problemas de seguridad en la zona, que impidieron la visita de supervisión y control del ganadero a su finca. Con la aplicación de la tecnología se obtuvo un aumento en el ingreso neto(en pesos del año 2000) de $12’352.500. El aumento significativo en porcentaje de preñez, compensa económicamente el menor al destete, haciendo viable y atractiva la aplicación de la tecnología en estos sistemas de producción.
Interrelaciones entre nutrición y fertilidad en bovinos.
Authors: Rúgeles P Clara
Published: August 2019

La ganadería ocupa uno de los principales renglones de desarrollo, tanto nacional como regional, y se considera que los ganados de la región descienden de animales importados con grandes méritos genéticos pero no adaptados a este medio. Asimismo, se sabe que los parámetros usados como indicadores de rendimiento desde el punto de vista de la reproducción, no alcanzan a los reconocidos comoideales y que son los reportados por otros países con condiciones ambientales más favorables (Grosserichter 1993).
Produccion in vitro de gas metano por gramineas forrajeras tropicales
Authors: Ley de Coss Alejandro , Guerra-Medina Enrique , Montañez-Valdez Oziel , Guevara H Francisco , Pinto R René , Reyes-Gutiérrez José Andrés
Published: August 2019

Objetivo. Estimar la producción de metano (CH4) por gramíneas tropicales fermentadas in vitro. Materiales y métodos. Una muestra de 20 g de materia seca de Cynodon nlemfuensis, Hyparrhenia rufa, Megathyrsus maximus y Digitaria swazilandensis más 200 ml de medio de cultivo se depositaron por triplicado en frascos de acero inoxidable estériles con flujo de CO2, se inocularon con 20 ml de líquido ruminal de bovino e incubaron a 38 °C por 24, 48, 72 y 96 h. Se evaluó producción total de gas, CH4, ácidos grasos volátiles, y pH en un diseño completamente al azar con tres repeticiones por tratamiento y la comparación de medias con Tukey; la concentración de bacterias totales y celulolíticas, se analizaron con la prueba de Kruskal-Wallis, y el procedimiento GLM con datos de rangos independientes de Wilcoxon. Resultados. H. rufa y D. swazilandensis tuvieron la menor producción total de gases (p<0.05), mientras que D. swazilandensis tuvo menor producción de CH4, mayor producción de ácido propónico (p<0.05) y menor pH a las 96 horas de incubación (p<0.05). D. swazilandensis mostró mayor eficiencia en la producción de energía por la menor producción de CH4 y mayor producción de propionato. La concentración de bacterias totales fue similar entre tratamientos (p>0.05), mientras que la concentración de bacterias celulolíticas fue menor en C. nlemfuensis y D. swazilandensis a la hora 96 de incubación (p<0.05). Conclusiones. La Digitaria swazilandensis, mostró condiciones favorables para tener menor producción total de metano y gases totales.
Spirocerca lupi en perros de Yucatán, México: Reporte de caso y estudio retrospectivo
Authors: Riodríguez-Vivas Roger Ivan , Cordero Leonardo Guillermo , Trinidad-Martínez Iris , Ojeda-Chi Melina M
Published: August 2019

Objetivo. Se describe el caso de un perro parasitado con Spirocera lupi en Yucatán, México, y además, se reportan los casos registrados en dos laboratorios durante 18 años de estudios parasitológicos y de necropsias (2000-2017). Materiales y métodos.Para el primer caso, se incluyen hallazgos de necropsia, histológicos y parasitológicos. Para los estudios retrospectivos se realizaron necropsias y estudios coprológicos de Flotación Centrifugada y de McMaster. Resultados. En el paciente del estudio de caso, durante la necropsia se observaron tres nódulos esofágicos que al realizar la incisión de los mismos, se visualizaron nematodos que correspondieron a S. lupi. En el estudio histológico se observó un granuloma eosinofílico que en su interior contenía el nematodo rodeado por un infiltrado inflamatorio moderado que estaba constituido por neutrófilos, eosinófilos, linfocitos, células plasmáticas y macrófagos; delimitado por una cápsula de tejido conectivo fibroso. En el estudio retrospectivo se encontraron prevalencias de 0.18 y 0.48% mediante pruebas coprológicas y estudios de necropsias, respectivamente. Conclusiones. Spirocerca lupi se encuentra presente en perros de Yucatán, México. Por lo tanto, sería importante considerar esta patología para el diagnóstico diferencial de problemas esofágicos y respiratorios en caninos.
Modelling the mechanical action of a front loading washing machine
Authors: Roberts Melanie E , Kueh Celia , Greenbank Emma , Clarke Daniel , Van Hove Sibylle , Simpson David J. W. , Williams Alan , Williams James
Published: August 2019

Fisher & Paykel Appliances is a major New Zealand appliance manufacturing company who, amongst other products, develops front- loading washing machines. Their development teams are committed to improving the machine performance. Machine performance is a combination of wash performance (soil removal and wear and tear), power and water consumption, and ease of use. The problem Fisher & Paykel Appliances posed to Mathematics-in-Industry New Zealand was to investigate mathematical models for the wash performance of front-loading washing machines due to mechanical action. Analysis of experimental data supplied by Fisher & Paykel Appliances did not identify the expected inverse relationship between soil removal and wear and tear, indicating that both metrics could be simultaneously improved. The experimental data is further used to identify a rela- tionship between drum speed and the spin dynamics, indicating that a re-configuration of the machine vanes could improve wash perfor- mance. A physical model of wash behaviour is developed to explore the relationship between drum speed and the actions of clothing. A video analysis approach demonstrates that a simple video set-up can be used to gain further insight into the trajectories and mixing of both experimental and genuine wash behaviour.
A Machine Learning Method for Identifying Lung Cancer Based on Routine Blood Indices: Qualitative Feasibility Study
Authors: Wu Jiangpeng , Zan Xiangyi , Gao Liping , Zhao Jianhong , Fan Jing , Shi Hengxue , Wan Yixin , Yu E , Li Shuyan , Xie Xiaodong
Published: August 2019

Background

Liquid biopsies based on blood samples have been widely accepted as a diagnostic and monitoring tool for cancers, but extremely high sensitivity is frequently needed due to the very low levels of the specially selected DNA, RNA, or protein biomarkers that are released into blood. However, routine blood indices tests are frequently ordered by physicians, as they are easy to perform and are cost effective. In addition, machine learning is broadly accepted for its ability to decipher complicated connections between multiple sets of test data and diseases.

Objective

The aim of this study is to discover the potential association between lung cancer and routine blood indices and thereby help clinicians and patients to identify lung cancer based on these routine tests.

Methods

The machine learning method known as Random Forest was adopted to build an identification model between routine blood indices and lung cancer that would determine if they were potentially linked. Ten-fold cross-validation and further tests were utilized to evaluate the reliability of the identification model.

Results

In total, 277 patients with 49 types of routine blood indices were included in this study, including 183 patients with lung cancer and 94 patients without lung cancer. Throughout the course of the study, there was correlation found between the combination of 19 types of routine blood indices and lung cancer. Lung cancer patients could be identified from other patients, especially those with tuberculosis (which usually has similar clinical symptoms to lung cancer), with a sensitivity, specificity and total accuracy of 96.3%, 94.97% and 95.7% for the cross-validation results, respectively. This identification method is called the routine blood indices model for lung cancer, and it promises to be of help as a tool for both clinicians and patients for the identification of lung cancer based on routine blood indices.

Conclusions

Lung cancer can be identified based on the combination of 19 types of routine blood indices, which implies that artificial intelligence can find the connections between a disease and the fundamental indices of blood, which could reduce the necessity of costly, elaborate blood test techniques for this purpose. It may also be possible that the combination of multiple indices obtained from routine blood tests may be connected to other diseases as well.
Factors That Contribute to the Use of Stroke Self-Rehabilitation Technologies: A Review
Authors: Vourganas Ioannis , Stankovic Vladimir , Stankovic Lina , Kerr Andrew
Published: August 2019

Background

Stroke is increasingly one of the main causes of impairment and disability. Contextual and empirical evidence demonstrate that, mainly due to service delivery constraints, but also due to a move toward personalized health care in the comfort of patients’ homes, more stroke survivors undergo rehabilitation at home with minimal or no supervision. Due to this trend toward telerehabilitation, systems for stroke patient self-rehabilitation have become increasingly popular, with many solutions recently proposed based on technological advances in sensing, machine learning, and visualization. However, by targeting generic patient profiles, these systems often do not provide adequate rehabilitation service, as they are not tailored to specific patients’ needs.

Objective

Our objective was to review state-of-the-art home rehabilitation systems and discuss their effectiveness from a patient-centric perspective. We aimed to analyze engagement enhancement of self-rehabilitation systems, as well as motivation, to identify the challenges in technology uptake.

Methods

We performed a systematic literature search with 307,550 results. Then, through a narrative review, we selected 96 sources of existing home rehabilitation systems and we conducted a critical analysis. Based on the critical analysis, we formulated new criteria to be used when designing future solutions, addressing the need for increased patient involvement and individualism. We categorized the criteria based on (1) motivation, (2) acceptance, and (3) technological aspects affecting the incorporation of the technology in practice. We categorized all reviewed systems based on whether they successfully met each of the proposed criteria.

Results

The criteria we identified were nonintrusive, nonwearable, motivation and engagement enhancing, individualized, supporting daily activities, cost-effective, simple, and transferable. We also examined the motivation method, suitability for elderly patients, and intended use as supplementary criteria. Through the detailed literature review and comparative analysis, we found no system reported in the literature that addressed all the set criteria. Most systems successfully addressed a subset of the criteria, but none successfully addressed all set goals of the ideal self-rehabilitation system for home use.

Conclusions

We identified a gap in the state-of-the-art in telerehabilitation and propose a set of criteria for a novel patient-centric system to enhance patient engagement and motivation and deliver better self-rehabilitation commitment.
Student and Tutor Satisfaction with an Online and Paper-based Clinical Assessment Tool. (Preprint)
Authors: Bright Philip , Bright Ollie
Published: August 2019

BACKGROUND

Assessment of students’ clinical competence in healthcare education typically involves the evaluation of their performance during a patient consultation. Direct observation of students with actual patients is important for the assessment of clinical skills prior to professional registration. The mini-clinical evaluation exercise (mini-CEX) has been widely established as part of a broad clinical assessment profile. The paper form has previously been validated in a number of healthcare scenarios including pre-registration osteopathic practice. Differences in satisfaction, when deploying the instrument through different media, are not widely explored.

OBJECTIVE

This study explored osteopathy students’ and tutors’ rating of satisfaction using the mini-CEX when administered via online and paper-based media. This was with a view to answer the following research question: Does the method of capture influence assessment satisfaction scores in the use of the mini-CEX?

METHODS

An online mini-CEX was developed using Google Forms and was initially trialled as a data entry process, with administration staff keying-in the completed paper assessment details post-hoc. Subsequently, Android-based tablets were used for direct capture of the observed clinical practice evaluation of students by tutors. This facilitated a comparison to the paper counterpart over the course of three academic years. The influence of gender and methods of assessment capture (paper and online) was explored with binary regression, Spearman's correlation and Kruskal Wallis test, with dependent variables of student and tutor satisfaction.

RESULTS

A total of 736 mini-CEX assessments of patient encounters were analysed, and 550 (75%) were completed online. The influence of the paper capture of assessment on satisfaction scores, compared to the online process, was not significant (odds ratio 1, CI 0.86 – 1.15). Student satisfaction ratings for female students assessed by male tutors indicated lower summary scores compared to same-sex pairings (P<.007). Correlation between all student and tutor satisfaction ratings was moderate (r2=0.62, 95% CI 0.57 – 0.66, P<.00001).

CONCLUSIONS

The findings suggest that there is no statistically significant difference between the two methods of delivery in terms of satisfaction of use for either examiner or student, potentially indicative of the suitability of the online version. While this has relevance to the teaching environment within osteopathy, there is applicability to other clinical healthcare. The role of gender as an influence in the satisfactory conduct of assessment warrants further investigation

CLINICALTRIAL

N/A
Promoting Reproducible Research for Characterizing Nonmedical Use of Medications Through Data Annotation: Description of a Twitter Corpus and Guidelines (Preprint)
Authors: O'Connor Karen , Sarker Abeed , Perrone Jeanmarie , Gonzalez Hernandez Graciela
Published: August 2019

BACKGROUND

Social media data are being increasingly used for population-level health research because it provides near real-time access to large volumes of consumer-generated data. Recently, a number of studies have explored the possibility of using social media data, such as from Twitter, for monitoring prescription medication abuse. However, there is a paucity of annotated data or guidelines for data characterization that discuss how information related to abuse-prone medications is presented on Twitter.

OBJECTIVE

This study discusses the creation of an annotated corpus suitable for training supervised classification algorithms for the automatic classification of medication abuse–related chatter. The annotation strategies used for improving interannotator agreement (IAA), a detailed annotation guideline, and machine learning experiments that illustrate the utility of the annotated corpus are also described.

METHODS

We employed an iterative annotation strategy, with interannotator discussions held and updates made to the annotation guidelines at each iteration to improve IAA for the manual annotation task. Using the grounded theory approach, we first characterized tweets into fine-grained categories and then grouped them into 4 broad classes—abuse or misuse, personal consumption, mention, and unrelated. After the completion of manual annotations, we experimented with several machine learning algorithms to illustrate the utility of the corpus and generate baseline performance metrics for automatic classification on these data.

RESULTS

Our final annotated set consisted of 16,443 tweets mentioning at least 20 abuse-prone medications including opioids, benzodiazepines, atypical antipsychotics, central nervous system stimulants, and gamma-aminobutyric acid analogs. Our final overall IAA was 0.86 (Cohen kappa), which represents high agreement. The manual annotation process revealed the variety of ways in which prescription medication misuse or abuse is discussed on Twitter, including expressions indicating coingestion, nonmedical use, nonstandard route of intake, and consumption above the prescribed doses. Among machine learning classifiers, support vector machines obtained the highest automatic classification accuracy of 73.00% (95% CI 71.4-74.5) over the test set (n=3271).

CONCLUSIONS

Our manual analysis and annotations of a large number of tweets have revealed types of information posted on Twitter about a set of abuse-prone prescription medications and their distributions. In the interests of reproducible and community-driven research, we have made our detailed annotation guidelines and the training data for the classification experiments publicly available, and the test data will be used in future shared tasks.
Iraq Mass Gathering Preparedness and Public Health Recommendations (Preprint)
Authors: Al Nsour Mohannad
Published: August 2019

UNSTRUCTURED

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Methods for Assessing Longitudinal Biomarkers of Time-to-Event Outcomes in CKD
Authors: Liu Qian , Smith Abigail R. , Mariani Laura H. , Nair Viji , Zee Jarcy
Published: August 2019

Background and objectives

Identifying novel biomarkers is critical to advancing diagnosis and treatment of CKD, but relies heavily on the statistical methods used. Inappropriate methods can lead to both false positive and false negative associations between biomarkers and outcomes. This study assessed accuracy of methods using computer simulations and compared biomarker association estimates in the NEPhrotic syndrome sTUdy NEtwork (NEPTUNE), a prospective cohort study of patients with glomerular disease.

Design, setting, participants, & measurements

We compared three methods for analyzing repeatedly measured biomarkers in proportional hazards models: (1) time-invariant average, that averages values over all follow-up and uses the average as a baseline covariate, (2) time-varying last observation carried forward (LOCF), that assumes the covariate is unchanged until the next observed value, and (3) time-varying cumulative average, that updates the average using values at or before each measurement.

Results

Under both true mechanisms of LOCF and cumulative average, simulation results showed the time-invariant average method often gave extremely inaccurate results. When LOCF was the true association mechanism, the cumulative average method often gave overestimated association estimates that were further away from the null. When cumulative average was the true mechanism, LOCF always underestimated the associations,i.e., closer to the null. In NEPTUNE, compared with the LOCF or cumulative average methods, hazard ratios estimated from the time-invariant average method were always higher.

Conclusions

Different analytic methods resulted in markedly different results. Using the time-invariant average produces inaccurate association estimates, whereas other methods can estimate additive (cumulative average) or instantaneous (LOCF) associations depending on the hypothesized underlying association mechanism and research question.
COUMARIN ANALOGUES AS A POTENTIAL INHIBITOR OF LEISHMANIASIS: A MULTI-TARGETING PROTEIN INHIBITION APPROACH BY MOLECULAR DOCKING
Authors: Kapoor Kapish
Published: August 2019

Leishmaniasis is one of the most dreadful diseases as a leading cause of death in most of the developed countries. In the given study molecular docking study was performed on the library of coumarin analogues as anti-leishmaniasis agents. Total 300 coumarins analogues were taken from Pubmed and were studied using a molecular docking study on trypanothione reductase from Leishmania infantum (PDB code: 2JK6 and 2P18) and Leishmania mexicana (PDB code: 3PP7). Molecular docking result revealed that most active compound COU-130 and COU-220 bind to the active site of the protein with amino acids present in the various proteins. In PDB 2JK6 the active compound binds to the amino acid thr-51 and ser-14 were binding to the active site, and in PDB 3PP7 the active compound binds amino acid thr-26 and in PDB 2P18 the active compound binds to the amino acid phe-219 and try-212. Further in vitro and in vivo study of selected coumarin analogues can be studied for their therapeutic potential in treating leishmaniasis.
AS REVISTAS DE DIVULGAÇÃO CIENTÍTICA E O ENSINO DE CIÊNCIAS: CIRCULAÇÃO E TEXTUALIZAÇÃO DOS CONHECIMENTOS CIENTÍFICOS
Authors: Busko Paula Simone
Published: August 2019

Este artigo tem como objetivo apresentar a relação entre a linguagem da ciência, popularizada por revistas de divulgação científica, o discurso e a escola. Quanto à metodologia empregada para analisar os textos que as revistas publicam e de como tais revistas são empregadas no âmbito escolar, deve-se verificar quais textos os alunos buscam com maior regularidade. A divulgação científica pode ser tratada como um conjunto que une a produção do conhecimento e em como este é formulado e como circula. Há possíveis análises que não deixam de ser consideradas - o produtor desta informação versus o consumidor destas leituras, neste caso o autor do texto, o professor e o aluno na escola. Nas escolas também há território e cultura, onde certos atores conseguem potencializar o aprendizado. No entendimento que os discursos podem produzir novos sentidos sobre o social chamo a atenção para a historicidade em que se constituem os discursos científicos, afinal, a história do ocidente é atravessada pela perspectiva de encontrar leis e valores universais de causalidade última.
DESENVOLVIMENTO DE MODELOS MENTAIS POR MEIO DA ELABORAÇÃO E APLICAÇÃO DE MODELOS FÍSICOS ALTERNATIVOS PARA O ENSINO DE ATOMÍSTICA
Authors: Piva Gabriela Martins , Almeida Letícia França de , Kohori Rodolfo Kasuyoshi , Gibin Gustavo Bizarria
Published: August 2019

O tema de modelos atômicos é importante no ensino de Química e de Ciências, entretanto, muitos estudantes apresentam dificuldades, em relação à próprio conceito de modelo científico (MELO e LIMA NETO, 2013) e quanto à estrutura dos átomos (FRANÇA, MARCONDES e CARMO, 2009). O referencial teórico empregado no trabalho é a teoria de modelos mentais de Johnson-Laird (1983). Foram desenvolvidos modelos moleculares físicos com materiais alternativos e de baixo custo para ensinar o conceito de modelo atômico e conceitos relacionados, como modelo científico, geometria molecular e ligação química. Os modelos foram utilizados em aulas regulares de Química em uma parceria com uma escola estadual de Educação Básica do município de Presidente Prudente - SP. Foi observado um grande avanço nos modelos expressos pelos alunos, para todos os conceitos abordados. Portanto, o emprego de modelos moleculares alternativos permitiu a realização de atividades didáticas nas quais houve uma evolução nos modelos mentais dos alunos sobre o conceito de modelo atômico e outros relacionados. A metodologia também permitiu que fosse realizado o levantamento dos modelos mentais dos alunos, com a manipulação do modelo físico e também por meio dos instrumentos de coleta de dados, como questionários, desenhos e representação por meio do próprio modelo físico.
ADEUS PROFESSOR, ADEUS PROFESSORA? NOVAS EXIGÊNCIAS EDUCACIONAIS E PROFISSÃO DOCENTE
Authors: Sant'Ana Camila de Fatima
Published: August 2019

O presente arquivo trás uma resenha sobre as colocações do autor no livro em questão. Os desafios apresentados aos docentes atualmente no exercício de sua profissão.
A CONTRIBUIÇÃO DOS ESPAÇOS NÃO FORMAIS DE EDUCAÇÃO NA FORMAÇÃO DOS LICENCIANDOS EM QUÍMICA DO IFRJ- NILÓPOLIS
Authors: Mendes Cleuber Fabiano Pereira , De Castro Denise Leal
Published: August 2019

Ao longo das últimas décadas os espaços não formais de educação têm aumentado consideravelmente em todo país, especialmente na região sudeste. Estudos voltados para esta temática confirmam que a educação desenvolvida nesses espaços é de fundamental importância na aprendizagem de conteúdos de divulgação científica na formação do licenciando. Este trabalho apresenta resultados de um questionário, aplicado a licenciandos em química de terceiro ao oitavo períodos do Instituto Federal de Educação Ciência e Tecnologia do Rio de Janeiro - campus Nilópolis, sobre a contribuição dos espaços não formais de educação na sua formação. A análise das respostas dadas ao questionário constituído por oito questões, sendo seis abertas e duas fechadas foram separadas em quatro categorias. Os resultados apontam uma necessidade de aproximar os espaços formais de ensino, como essa instituição, dos espaços não formais de educação, como os museus e centros de ciência e tecnologia. Sob a visão dos licenciandos, os espaços de educação não formal podem contribuir de forma positiva tanto para sua formação profissional, quanto para sua prática docente no futuro.
ANÁLISE DOS CONTEÚDOS DE DIVERSIDADE BIOLÓGICA COM ÊNFASE EM FILOGENIA NOS EXAMES VESTIBULARES
Authors: Cordeiro Rogério Soares , Morini Maria Santina de Castro , Wuo Moacir
Published: August 2019

O presente trabalho teve o objetivo de analisar a temática biodiversidade no contexto da sistemática filogenética em exames vestibulares nacionais. Para atender a esse propósito, foi feita uma análise de 154 questões de múltipla escolha, aplicadas em exames vestibulares que ocorreram entre os anos de 1994 e 2016. As questões foram lidas e interpretadas de acordo com a técnica de Análise de Conteúdo. Foi elaborada uma ficha dotada de cinco critérios e subcategorias. Os resultados indicam que 46,7% das perguntas procedem de universidades públicas federais e, 77,93% destas, utilizam cladogramas como recurso para discutir biodiversidade. As abordagens mais frequentes tratam da biologia geral, e os assuntos mais específicos são zoologia e botânica, respectivamente. Resultados mostram pouca articulação de outros conceitos biológicos com a sistemática filogenética e apenas 55,85% das questões trazem termos de filogenia contextualizados, sendo que 19,48% utilizam termos específicos. Os cladogramas são uma realidade nos vestibulares nacionais, o que requer maior apropriação e domínio desse importante recurso das ciências biológicas para que, efetivamente, seja feita a interlocução entre evolução e biodiversidade.
O PENSAMENTO CRÍTICO NO CONTEXTO DA ALFABETIZAÇÃO CIENTÍFICA: UM ESTUDO COM FUTUROS PROFESSORES DE CIÊNCIAS
Authors: Façanha Alessandro Augusto Barros , Chianca Renan Cirne , Felix Clara Patricia
Published: August 2019

Este estudo revela os resultados de uma investigação acerca do conhecimento profissional de futuros professores de ciências sobre a habilidade do pensamento crítico e sua relação ao contexto da alfabetização científica com o intuito de se discutir a formação desses professores no âmbito de sua profissionalidade no que corresponde à compreensão sobre o pensamento crítico como uma habilidade cognitiva necessária para ensinar ciências e promover alfabetização científica em aulas de ciências. Foi realizado um estudo de natureza descritiva com estudantes de pedagogia de uma universidade pública de referência da formação de professores e nas pesquisas que envolvem o ensino das ciências. Os resultados, apesar de circunscritos ao estudo em questão, auxiliam na compreensão do processo de formação de professores e demonstra, dentre outras constatações, a fragilidade da formação no contexto do ensino de ciências bem como um descompasso entre a profissionalidade e as necessidades atuais para a promoção da alfabetização científica nos anos iniciais da educação básica.
Regression verification for automated evaluation of students programs
Authors: Vujosevic-Janicic Milena , Maric Filip
Published: August 2019

Regression verification is a form of software verification based on formal static analysis of code, which is used, since recently, in several domains. In this paper we examine potentials of using it in one novel domain ? in automated evaluation of students programs. We propose an approach that provides precise assessment of functional correctness of student programs (while it does not address nor affect the teaching methodology). We describe our open-source, publicly available implementation of the approach, which is built on top of the compiler infrastructure LLVM and the software verification tool LAV. The results of evaluating the proposed approach on two real-world corpora of student programs and on a number of classic algorithms show that the proposed approach can be used as a precise and reliable supplementary technique in grading of student programs at introductory programming courses, algorithms courses and programming competitions.
Radon concentrations in henna(Lawsonia inermis) leaf samples collected from Basrah, Iraq
Authors: Ahmed Rasha , Mohammed Raghad , Radhi Ali
Published: August 2019

Henna leaves are a priority material for hair dyes and body tattoos and have been used for this purpose for decades. In Iraq, henna is used widely but it requires substantial controls. Iraq is considered an environmentally polluted area as a result of the wars it has experienced, hence, this study has been conducted to calculate the level of 222Rn contamination in henna leaves using a CR-39 nuclear track detector. The leaves were collected from the province of Basrah, which is located in southern Iraq and is famous for cultivation of this plant. The radon concentrations were found to range from 12.140 to 16.255 Bqm?3 in Al-Faw, and from 7.613 to 11.111 Bqm?3 in Abu Al Khasib. Radon activity ranged from 6.09?10?4 to 8.16?10?4 Bq Radon specific activity ranged from 1.22?10?4 to 1.63?10?4 Bqg?1 in Al-Faw, and from 7.64?10?5 to 1.12?10?4 Bqg?1 in Abu Al Khasib. The radon exhalation rate ranged from 4.05?10?4 to 5.43?10?4 with an average of 4.69?10?4 Bqm?2d?1 in Al-Faw, and from 2.54 10?4 to 3.71?10?4 with an average of 3.22 10?4 Bqm ?2d?1 in Abu Al Khasib. After obtaining the results, one can conclude that the henna plant collected from these areas is safe for human use and is free from high rates of 222Rn.
Neutronic safety analysis of proposed reactor technologies for Ghana’s nuclear power plant using the MCNP code
Authors: Abrefah Rex , Atsu Prince , Sogbadji Robert
Published: August 2019

In pursuance of sufficient, stable and clean energy to solve the ever-looming power crisis in Ghana, the Nuclear Power Institute of the Ghana Atomic Energy Commission has on the agenda to advise the government on the nuclear power to include in the country's energy mix. After consideration of several proposed nuclear reactor technologies, the Nuclear Power Institute considered a high pressure reactor or vodo-vodyanoi energetichesky reactor as the nuclear power technologies for Ghana's first nuclear power plant. As part of technology assessments, neutronic safety parameters of both reactors are investigated. The MCNP neutronic code was employed as a computational tool to analyze the reactivity temperature coefficients, moderator void coefficient, criticality and neutron behavior at various operating conditions. The high pressure reactor which is still under construction and theoretical safety analysis, showed good inherent safety features which are comparable to the already existing European pressurized reactor technology.
Evaluation of treatment outcome in patients with acute-on-chronic liver failure using clinical scores
Authors: Milovanovic Tamara , Stojkovic-Lalosevic Milica , Dragasevic Sanja , Jocic Nevena , Baralic Marko , Dumic Igor , Pavlovic-Markovic Aleksandra
Published: August 2019

Introduction/Objective. Due to a very high mortality risk, acute-on-chronic liver failure (ACLF) patients require early identification and intensive treatment. Precise prediction is crucial for determining the urgency degree and therapy appropriateness, considering high mortality and multitude of clinical resources. The aim of our study was to determine the exact cut-off values of various prognostic scores in the prediction of morality of ACLF. Methods. This prospective study includes chronic liver disease (CLD) patients, admitted due to decompensation, that were subsequently diagnosed with ACLF at the Emergency unit. All patients were evaluated based on various prognostic scores, including Child?Pugh, MELD Na, MELD, SOFA, APACHE II, and CLIF C, which were calculated on admission. Results. Alcoholic liver disease (ALD) was the most common underlying CLD cause (77.9%), followed by viral (8.6%), autoimmune (7.7%), and other causes (5.8%). A total of 37.5% of the patients died at the end of the first month of treatment. Average values of Child?Pugh, MELD Na, MELD, SOFA, APACHE II, and CLIF C scores were significantly higher in patients who died compared to survivors (p < 0.05). CLIF C score showed the best performance with a cut-off value of 50.5, with a sensitivity of 94.9% and specificity of 40%. Conclusion. ACLF remains a condition with a high short-term mortality. Of all of the scores examined in our study, CLIF C proved to be the best scoring system for predicting short term and end of treatment mortality in patients with ACLF.
Insulin-and-Glucagon Artificial Pancreas Versus Insulin-Alone Artificial Pancreas: A Short Review
Authors: Haidar Ahmad
Published: August 2019

IN BRIEF The advantage of the insulin-and-glucagon artificial pancreas is based on the rapid effect of subcutaneous glucagon delivery in preventing hypoglycemia compared to suspension of insulin delivery. In short-term studies, the dual-hormone artificial pancreas reduced daytime hypoglycemia, especially during exercise, compared to the insulin-alone artificial pancreas, but the insulin-alone system seemed sufficient in eliminating nocturnal hypoglycemia. The comparative benefits of the single- and dual-hormone systems for improving A1C and preventing severe hypoglycemia remain unknown.
Why Download Data: The Benefits and Challenges of More Diabetes Data
Authors: Arbiter Brandon , Look Howard , McComb Lindsay , Snider Christopher
Published: August 2019

IN BRIEF Diabetes care lends itself to interactions centered around data—counting carbohydrate for meals, calculating correction doses, viewing logbooks or device data, and discussing A1C levels—and digital technology has enhanced diabetes care through the improved collection and analysis of data from multiple sources. With these technological advancements have come great improvements in quality of life for people with type 1 diabetes. These technologies allow for more informed and immediate decision-making through better access to blood glucose data and sometimes allow the devices themselves to make decisions, removing the need for patients or clinicians to be involved in decision-making altogether. At the same time, these new technologies bring new challenges for both patients and health care providers, who must now analyze and make sense of more diabetes data.
The Engine Performance Characteristics of an IDI Diesel Engine Fueled by Soybean Oil Methyl Esters
Authors: Ghurri A , Keun S K
Published: August 2019

An experimental investigation was conducted to evaluate the performance of anindirect injection (IDI) diesel engine using diesel (D100) and diesel-biodieselblends (BD25, BD45, BD65) separately. The engine was run in various engineloads at constant engine speed ranging from 1000 to 2400 rpm with an interval200 rpm. The results showed that the biodiesel content decreased the enginetorque and power. This might be mainly affected by the lower LHV of thebiodiesel, and also the worse combustion due to higher density of the biodieselcompared to the diesel fuel. The loss of power due to lower heating value ofbiodiesel were not as high as the difference in their heating value that might bedown to the better lubricity of biodiesel as proved in the higher brake thermalefficiency and mechanical efficiency when using the biodiesel blends. The brakespecific fuel consumption is higher with the increase of biodiesel content but thediesel fuel delivered the highest energy to run the engine. The maximum pressureinside cylinder and the heat release rate of D100 is slightly higher than those ofbiodiesel blends.Keywords: diesel engine, biodiesel, engine performance, emission.