643 research outputs found
Centralized Control System Design for Underwater Transportation using two Hovering Autonomous Underwater Vehicles (HAUVs)
In this paper, a centralized control system is designed for the two HAUVs undertaking underwater transportation of a spherical payload via cylindrical manipulators. First, the nonlinear coupled dynamic model is developed considering the rigid body connection method for transportation. The effect of the hydrodynamic, hydrostatic and thrust parameters are taken about the centre of the combined body i.e. the centre of payload. Path trajectory is generated using the minimum snap trajectory algorithm. The trajectory is divided into segments for each directional motion which is further divided into the waypoints based on the time step of the duration. The path between two waypoints is represented by a 7th order polynomial. The centralized control system is designed to follow the desired trajectory. The control system is designed using PID controllers for the motion control in each direction. The main technical requirements are the stability of the payload, accurate trajectory tracking and robustness to overcome uncertainties. Stability cannot be compromised because of the rigid connection between the vehicles and the payload, whereas, tracking is given a tolerance of ±5%. Transportation task is observed for the desired motion in the horizontal plane. The time domain motion simulation results show that the desired trajectory has been accurately followed by the combined system while meeting the technical requirements
Leaves of roadside plants as bioindicator of traffic related lead pollution during different seasons in Sargodha, Pakistan
Plants are important bioindicators of heavy metal environmental pollution. For this purpose a study was conducted during winter and summer seasons in Sargodha, Pakistan. Three roadside plants that is Dalbergia sissoo Roxb., Prosopis juliflora L. and Eucalyptus spp. were collected from different locations. The study area was divided into five on the basis of traffic density and industrial pollution. These were Urban, Suburban, Industrial, Roadside and Rural. It was found that lead concentration was highest in the plants that were collected from industrial site in Dalbergia during winter and summer that is 421.43 ± 1 9.30 and 429.37 ± 14.49 ug g-1 respectively and lowest at the control site (rural site) 69.57 ± 36.80 ug g-1 in Eucalyptus during winter and 61.89 ± 35.97 ug g-1 in Prosopis during summer. All the three selected plants proved to be good indicators of lead pollution and due to their diverse distribution in different parts of the world their leaves can be used as bioindicators of lead pollution.Key words: Bioindicator, lead, roadside plants, seasonal variation
Isolation of cellulolytic activities from Tribolium castaneum (red flour beetle)
Cellulolytic enzymes have immense potential to convert cellulosic biomass into useful products. Tribolium castaneum crude proteins were isolated to screen the cellulolytic activities. The activity was established by substrate-agar plate assay and confirmed by endoglucanase assay. Cellulolytic activitywas further purified and characterized using the different chromatographic techniques and electrophoresis. Gel filtration chromatography showed the presence of multiple forms of enzyme activities with different molecular weights. Stability of enzyme activity was investigated at differenttemperatures and pH. Optimum pH for was found 4.8 at 40oC determined as optimum temperature. Gradually decreasing Enzyme activity remained half at 60oC. Zymography and SDS-PAGE showed the presence of multiple forms of endoglucanase activities (Cel I and Cel II) with molecular weight of 55 kDaand 35 kDa
Volatilidade do mercado de ações do Paquistão: uma comparação de modelos do tipo Garch com cinco
This study conducts empirical analyses modeling the volatility of Pakistani stock market over the period of 1st January 2008 to 30th June 2018 via different GARCH type Model; Symmetric (GARCH & GARCH-M) and Asymmetric (EGARCH & TGARCH) with five different Distribution Techniques such as Normal Distribution (Norm), Student’s t Distribution (Std.), Generalized Error Distribution (GED), Student’s t Distribution with fix the degree of freedom (Std. with fix DOF) and Generalized Error Distribution with fix parameters (GED with fix parameters). The results are shown in GARCH (1, 1) lagged conditional variance and squared disturbance which effects conditional variance is significant in all distribution. GARCH-M (1, 1) depicts a positive significant at 1% results in Std. and GED which indicates the existence of risk premium and insignificant in rest of the distribution on. EGARCH and TGARCH both are found to leverage effect significant at 1% level. In determining the accuracy and adequacy of forecasting density and choice of volatility model the results on simulated data indicates choice of conditional distribution appear as a more dominant factor. EGARCH model with Student’s t the distribution technique is delivered satisfactory results as compare to other models which censored by statistical tools of maximum Log Likelihood, minimum AIC, and SIC. The previous study of Pakistani Stock Market is limited to GARCH family models with one or two distributions. This study covers the limitations and also contributes existing literature in this regard. This research is considered important for investors, policymakers, and researchers.Este estudio realiza análisis empíricos que modelan la volatilidad del mercado de valores pakistaní durante el período del 1 de enero de 2008 al 30 de junio de 2018 a través de diferentes modelos de tipo GARCH; Simétrico (GARCH & GARCH-M) y Asymmetric (EGARCH & TGARCH) con cinco técnicas de distribución diferentes, como la distribución normal (Norm), la distribución t de Student (Std.), La distribución de errores generalizada (GED), la distribución t de Student con la corrección del grado de libertad (Std. con corrección DOF) y Distribución de errores generalizada con parámetros de corrección (GED con parámetros de corrección). Los resultados se muestran en GARCH (1, 1) varianza condicional retrasada y perturbación al cuadrado, lo que afecta a la varianza condicional es significativo en toda la distribución. GARCH-M (1, 1) muestra un resultado positivo significativo al 1% en la norma. y GED, que indica la existencia de prima de riesgo e insignificante en el resto de la distribución en. Tanto EGARCH como TGARCH tienen un efecto de apalancamiento significativo al nivel del 1%. Al determinar la precisión y la adecuación de la densidad de pronóstico y la elección del modelo de volatilidad, los resultados en datos simulados indican que la elección de la distribución condicional aparece como un factor más dominante. El modelo EGARCH con la técnica de distribución de Student se entrega con resultados satisfactorios en comparación con otros modelos que están censurados por las herramientas estadísticas de máxima probabilidad de registro, mínimo AIC y SIC. El estudio anterior de la Bolsa de Valores de Pakistán se limita a los modelos de la familia GARCH con una o dos distribuciones. Este estudio cubre las limitaciones y también aporta la literatura existente en este sentido. Esta investigación se considera importante para los inversores, los responsables políticos y los investigadores.Este estudo realiza análises empíricas modelando a volatilidade do mercado de ações paquistanês no período de 1º de janeiro de 2008 a 30 de junho de 2018 através de diferentes modelos do tipo GARCH; Simétrico (GARCH & GARCH-M) e Assimétrico (EGARCH & TGARCH) com cinco diferentes Técnicas de Distribuição, como Distribuição Normal (Norm), Distribuição t de Student (Padrão), Distribuição de Erro Generalizada (GED), Distribuição t de Student com correção do grau de liberdade (Std. com correção de DOF) e distribuição de erros generalizada com parâmetros de correção (GED com parâmetros de correção). Os resultados são apresentados na variância condicional defasada GARCH (1, 1) e na perturbação quadrada que afeta a variância condicional em todas as distribuições. GARCH-M (1, 1) representa um significante positivo com resultados de 1% em Std. e GED que indica a existência de prêmio de risco e insignificante em resto da distribuição em. EGARCH e TGARCH ambos são encontrados para alavancar o efeito significativo ao nível de 1%. Ao determinar a precisão e a adequação da densidade de previsão e a escolha do modelo de volatilidade, os resultados em dados simulados indicam que a escolha da distribuição condicional aparece como um fator mais dominante. O modelo EGARCH com Student t a técnica de distribuição apresenta resultados satisfatórios quando comparado a outros modelos que foram censurados por ferramentas estatísticas de máxima Likelihood, mínima AIC e SIC. O estudo anterior do mercado de ações paquistanês é limitado a modelos de família GARCH com uma ou duas distribuições. Este estudo cobre as limitações e também contribui com a literatura existente a esse respeito. Esta pesquisa é considerada importante para investidores, formuladores de políticas e pesquisadores
Design and development of autonomous robotic fish for object detection and tracking
In this article, an autonomous robotic fish is designed for underwater operations like object detection and tracking along with collision avoidance. The computer-aided design model for prototype robotic fish is designed using the Solid Works® software to export an stereolithography (STL) file to MakerBot, a 3D printer, to manufacture the parts of robotic fish using polylactic acid thermoplastic polymer. The precise maneuverability of the robotic fish is achieved by the propulsion of a caudal fin. The oscillation of the caudal fin is controlled by a servomotor. A combination of visual and ultrasonic sensors is used to track the position and distance of the desired object with respect to the fish and also to avoid the obstacles. The robotic fish has the ability to detect an object up to a distance of 90 cm at normal exposure conditions. A computational fluid dynamics analysis is conducted to analyze the fluid hydrodynamics (flow rate of water and pressure) around the hull of a robotic fish and the drag force acting on it. A series of experimental results have shown the effectiveness of the designed underwater robotic fish. </jats:p
Comparative metabolomics analysis of milk components between Italian Mediterranean buffaloes and Chinese Holstein cows based on LC-MS/MS technology
Buffalo and cow milk have a very different composition in terms of fat, protein, and total solids. For a better knowledge of such a difference, the milk metabolic profiles and characteristics of metabolites was investigated in Italian Mediterranean buffaloes and Chinese Holstein cows were investigated by liquid chromatography tandem-mass spectrometry (LC-MS/MS) in this study. Totally, 23 differential metabolites were identified to be significantly different in the milk from the two species of which 15 were up-regulated and 8 down-regulated in Italian Mediterranean buffaloes. Metabolic pathway analysis revealed that 4 metabolites (choline, acetylcholine, nicotinamide and uric acid) were significantly enriched in glycerophospholipid metabolism, nicotinate and nicotinamide metabolism, glycine, serine and threonine metabolism, as well as purine metabolism. The results provided further insights for a deep understanding of the potential metabolic mechanisms responsible for the different performance of Italian Mediterranean buffaloes’ and Chinese Holstein cows’ milk. The findings will offer new tools for the improvement and novel directions for the development of dairy industry
Three-dimensional visualization software assists learning in students with diverse spatial intelligence in medical education
This study evaluated effect of mental rotation (MR) training on learning outcomes and explored effectiveness of teaching via three-dimensional (3D) software among medical students with diverse spatial intelligence. Data from n = 67 student volunteers were included. A preliminary test was conducted to obtain baseline level of MR competency and was utilized to assign participants to two experimental conditions, i.e., trained group (n = 25) and untrained group (n = 42). Data on the effectiveness of training were collected to measure participants\u27 speed and accuracy in performing various MR activities. Six weeks later, a large class format (LCF) session was conducted for all students using 3D software. The usefulness of technology-assisted learning at the LCF was evaluated via a pre- and post-test. Students\u27 feedback regarding MR training and use of 3D software was acquired through questionnaires. MR scores of the trainees improved from 25.9±4.6 points to 28.1±4.4 (P = 0.011) while time taken to complete the tasks reduced from 20.9±3.9 to 12.2±4.4 minutes. Males scored higher than females in all components (P = 0.016). Further, higher pre- and post-test scores were observed in trained (9.0±1.9 and 12.3±1.6) versus untrained group (7.8±1.8; 10.8±1.8). Although mixed-design analysis of variance suggested significant difference in their test scores (P \u3c 0.001), both groups reported similar trend in improvement by means of 3D software (P = 0.54). Ninety-seven percent of students reported technology-assisted learning as an effective means of instruction and found use of 3D software superior to plastic models. Software based on 3D technologies could be adopted as an effective teaching pedagogy to support learning across students with diverse levels of mental rotation abilities
The Causal Effect of Vitamin D Binding Protein (DBP) Levels on Calcemic and Cardiometabolic Diseases: A Mendelian Randomization Study
Background: Observational studies have shown that vitamin D binding protein (DBP) levels, a key determinant of 25-hydroxy- vitamin D (25OHD) levels, and 25OHD levels themselves both associate with risk of disease. If 25OHD levels have a causal influence on disease, and DBP lies in this causal pathway, then DBP levels should likewise be causally associated with disease. We undertook a Mendelian randomization study to determine whether DBP levels have causal effects on common calcemic and cardiometabolic disease. Methods and Findings: We measured DBP and 25OHD levels in 2,254 individuals, followed for up to 10 y, in the Canadian Multicentre Osteoporosis Study (CaMos). Using the single nucleotide polymorphism rs2282679 as an instrumental variable, we applied Mendelian randomization methods to determine the causal effect of DBP on calcemic (osteoporosis and hyperparathyroidism) and cardiometabolic diseases (hypertension, type 2 diabetes, coronary artery disease, and stroke) and related traits, first in CaMos and then in large-scale genome-wide association study consortia. The effect allele was associated with an age-and sex-adjusted decrease in DBP level of 27.4 mg/l (95% CI 24.7, 30.0; n=2,254). DBP had a strong observational and causal association with 25OHD levels (p=3.2x10(-19)). While DBP levels were observationally associated with calcium and body mass index (BMI),these associations were not supported by causal analyses. Despite well-powered sample sizes from consortia, there were no associations of rs2282679 with any other traits and diseases: fasting glucose (0.00 mmol/l [95% CI -0.01, 0.01]; p=1.00; n=46,186); fasting insulin (0.01 pmol/l [95% CI -0.00, 0.01,] ;p=0.22; n=46,186); BMI (0.00 kg/m(2) [95% CI -0.01, 0.01]; p=0.80; n=127,587); bone mineral density (0.01 g/cm(2) [95% CI -0.01, 0.03]; p=0.36; n=32,961); mean arterial pressure (-0.06 mm Hg [95% CI -0.19, 0.07]); p=0.36; n=28,775); ischemic stroke (odds ratio [OR] = 1.00 [95% CI 0.97, 1.04]; p=0.92; n=12, 389/62, 004 cases/controls); coronary artery disease (OR = 1.02 [95% CI 0.99, 1.05]; p=0.31; n=2,233/64, 762); or type 2 diabetes (OR = 1.01 [95% CI 0.97, 1.05]; p=0.76; n=9, 580/53, 810). Conclusions: DBP has no demonstrable causal effect on any of the diseases or traits investigated here, except 25OHD levels. It remains to be determined whether 25OHD has a causal effect on these outcomes independent of DBP
Successful treatment of methemoglobinemia in an elderly couple with severe cyanosis: two case reports
Ultrasound-assisted extraction of polyphenols from potato peels: profiling and kinetic modelling
peer-reviewedUltrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R2 > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.The authors acknowledge financial support from the ‘NovTechIng’ project funded under the Food Institutional Research Measure (Project No. FIRM/11/F/050) by the Irish Department of Agriculture, Food and Marine
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