415 research outputs found
Is early correction of congenital ventricular septal defect a better option in a developing country
OBJECTIVE: To assess and evaluate the effectiveness of early ventricular septal defect (VSD) repair in a developing country by comparing the outcomes in two age groups.
METHODS: A total of 39 patients underwent VSD repair at a tertiary care hospital in Karachi over a period of 2.5 years. Patients were divided into Group 1 (years) and Group 2 (2-18 yrs). Perioperative and postoperative variables were reviewed retrospectively for each patient and compared with the development of complications and the effect on postoperative recovery times. The data was analyzed using Mann Whitney test for continuous variables and Fischer\u27s exact test for categorical variables.
RESULTS: Mean age at surgery was 10.1 +/- 7.0 months and 108.5 +/- 54.0 months for both groups, respectively. Two patients died. Procedure time was not affected by decreasing age (p = 0.622) but Cardio pulmonary Bypass duration (p = 0.040) and Aortic Cross Clamp time (p = 0.063) were significantly affected. No associated significance was obtained when hospital stay (p = 0.085) was observed. Increased duration of ventilation (p = 0.000) and length of ICU stay (p = 0.003) were highly significant for the younger age group. Presence of residual VSD (p = 0.025) was also significantly affected by lower age. There was no significant difference in the number of patients with complications (p = 1.000) among the 2 groups.
CONCLUSION: Age does not increase morbidity rates after VSD repair although postoperative recovery times are increased with decreasing age. Hence, there is no justification in delaying VSD repair
Experimental Demonstration and Performance Enhancement of 5G NR Multiband Radio over Fiber System Using Optimized Digital Predistortion
This paper presents an experimental realization of multiband 5G new radio (NR) optical front haul (OFH) based radio over fiber (RoF) system using digital predistortion (DPD). A novel magnitude-selective affine (MSA) based DPD method is proposed for the complexity reduction and performance enhancement of RoF link followed by its comparison with the canonical piece wise linearization (CPWL), decomposed vector rotation method (DVR) and generalized memory polynomial (GMP) methods. Similarly, a detailed study is shown followed by the implementation proposal of novel neural network (NN) for DPD followed by its comparison with MSA, CPWL, DVR and GMP methods. In the experimental testbed, 5G NR standard at 20 GHz with 50 MHz bandwidth and flexible-waveform signal at 3 GHz with 20 MHz bandwidth is used to cover enhanced mobile broad band and small cells scenarios. A dual drive Mach Zehnder Modulator having two distinct radio frequency signals modulates a 1310 nm optical carrier using distributed feedback laser for 22 km of standard single mode fiber. The experimental results are presented in terms of adjacent channel power ratio (ACPR), error vector magnitude (EVM), number of estimated coefficients and multiplications. The study aims to identify those novel methods such as MSA DPD are a good candidate to deploy in real time scenarios for DPD in comparison to NN based DPD which have a slightly better performance as compared to the proposed MSA method but has a higher complexity levels. Both, proposed methods, MSA and NN are meeting the 3GPP Release 17 requirements
Price and Income Elasticities of Crude Oil Demand: Cross Country Analysis
Volatility in crude oil price is the main issue in this era. Great volatility in price of crude oil affects the demand of oil directly and indirectly in developing countries because these countries are oil importing countries especially Pakistan, India and China. Crude oil therefore contributes to and thereby influences the GDP of the country as a source of energy. It is very critical and essential for any country to explore and produce gas to improve energy shortage, for some deliberate importance of gas because natural gas is very clean, cheap and sustainable source to produce energy within a country. This study aimed to analyze the price and income elasticities of crude oil demand in developing countries time series data used from the period of 1971-2014. ADF test was used to check the stationary of variables and it is seem that all variable are not stationary at level. ARDL used for co integration and all variables of the models have long run relation with dependent and explanatory variables. Price and income elasticities of crude oil demand were measured in short and long run for developing countries and it was concluded that long run elasticities of price and income were less inelastic or some cases like China was elastic than short run elasticities of price and income of crude oil demand. It was suggested that oil importer countries should explore the alternatives of oil within a country to fulfill the domestic demand
Future of ammonium nitrate after Beirut (Lebanon) explosion
Ammonium nitrate (NH4NO3) is a chemical compound that is mostly found as a colorless and/or white to gray crystalline solid, odorless beads, and easily soluble in water. The molecular weight, specific gravity, melting, and boiling point of NH4NO3 are 80.06, 1.725, 169.51 °C, and 210 °C, respectively (Rao, 2014). Higher temperature (>210 °C) easily decomposes NH4NO3 and producing toxic gasses, especially nitrogen oxides, and may also cause an explosion (Han et al., 2015). At room temperature, pure NH4NO3 neither flammable or combustible, but when heated, normally, it is decomposed into non-explosive gases such as oxygen. Nevertheless, it can also be decomposed into explosive material by detonation (Xia et al., 2019). Ammonium nitrate is strongly oxidant that easily detonates under certain circumstances, which include higher temperature (>210 °C), confinement, and impurities (Health Safety Executive, 2004).The authors would like to appreciate the valuable comments from the editors and anonymous reviewers to improve the quality of this study. The authors confirm that no funding was received for his work
Effect of animal manure, crop type, climate zone, and soil attributes on greenhouse gas emissions from agricultural soils A global meta-analysis
Agricultural lands, because of their large area and exhaustive management practices, have a substantial impact on the earth's carbon and nitrogen cycles, and agricultural activities consequence in discharges of greenhouse gases (GHGs). Globally, greenhouse gases (GHGs) emissions especially carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from the agricultural sector are increasing due to anthropogenic activities. Although, the application of animal manure to the agricultural soil as an organic fertilizer not only improves soil health and agricultural production but also has a significant impact on GHGs emissions. But the extent of GHGs emissions in response to manure application under diverse environmental conditions is still uncertain. Here, a meta-analysis study was conducted using field data (48 peer-reviewed publications) published from 1989 to 2019. Meta-analysis results showed that poultry manure considerably increased CO2, CH4, and N2O emissions than pig and cattle manure. Furthermore, application of poultry manure also increased (ÂŻ(ălnRRă^ ) =0.141, 95% CI =0.526-0.356) GWP (global warming potential) of total soil GHGs emissions. While, the significant effects on CO2, CH4, and N2O emissions also occurred at manure rate > 320 kg N ha-1 and > 60% water filled pore space. The maximum concentrations of CO2, CH4, and N2O emissions were observed in neutral soils (ÂŻ(ălnRRă^ ) =3.375, 95% CI =3.323-3.428), alkaline soils (ÂŻ(ălnRRă^ ) =1.468, 95% CI =1.403-1.532), and acidic soils (ÂŻ(ălnRRă^ ) =2.355, 95% CI =2.390-2.400), respectively. Soil texture, climate zone and crop type were also found significant factors to increase GHGs emissions. Thus, this meta-analysis revealed a knowledge gap concerning the consequences of animal manure application and rate, climate zone, and physicochemical properties of soil on GHGs emissions from agricultural soils.Awais Shakoor would like to express his gratitude for the grant provided by the University of Lleida, Spain. The authors would like to appreciate the valuable comments from the editors and anonymous reviewers to improve the quality of this study
Lane Line Detection and Object Scene Segmentation Using Otsu Thresholding and the Fast Hough Transform for Intelligent Vehicles in Complex Road Conditions
An Otsu-threshold- and Canny-edge-detection-based fast Hough transform (FHT) approach to lane detection was proposed to improve the accuracy of lane detection for autonomous vehicle driving. During the last two decades, autonomous vehicles have become very popular, and it is constructive to avoid traffic accidents due to human mistakes. The new generation needs automatic vehicle intelligence. One of the essential functions of a cutting-edge automobile system is lane detection. This study recommended the idea of lane detection through improved (extended) Canny edge detection using a fast Hough transform. The Gaussian blur filter was used to smooth out the image and reduce noise, which could help to improve the edge detection accuracy. An edge detection operator known as the Sobel operator calculated the gradient of the image intensity to identify edges in an image using a convolutional kernel. These techniques were applied in the initial lane detection module to enhance the characteristics of the road lanes, making it easier to detect them in the image. The Hough transform was then used to identify the routes based on the mathematical relationship between the lanes and the vehicle. It did this by converting the image into a polar coordinate system and looking for lines within a specific range of contrasting points. This allowed the algorithm to distinguish between the lanes and other features in the image. After this, the Hough transform was used for lane detection, making it possible to distinguish between left and right lane marking detection extraction; the region of interest (ROI) must be extracted for traditional approaches to work effectively and easily. The proposed methodology was tested on several image sequences. The least-squares fitting in this region was then used to track the lane. The proposed system demonstrated high lane detection in experiments, demonstrating that the identification method performed well regarding reasoning speed and identification accuracy, which considered both accuracy and real-time processing and could satisfy the requirements of lane recognition for lightweight automatic driving systems
Ad hoc and Opportunistic Routing in Static Scatternet Environment
Abstract Peer-to-peer connectivity between mobile phones using technologies such as Bluetooth has given a new dimension to the mobile communication. Peers through the help of various underlying protocols can form piconets and scatternets to transparently communicate the content across the network. There however are issues like reliability in communication, delay and the cost of communication that need to be considered before resorting to this form of communication. This paper presents a study where opportunistic concept such as Bubble Rap is tested in Bluetooth ad hoc networking environment. The notion behind this research is to study the properties of these two networking environments, since opportunistic networks are derived from ad hoc networks. Thus, study of these two different environments yet related to each other may help us find new ways of message forwarding in Bluetooth communication environment. This paper is aimed at investigating the behaviour of nodes present in Bluetooth static scatternet environment by 1) studying message transfer from a source to destination using traditional ad hoc communication protocols such as AODV and 2) message transfer using opportunistic algorithms such as Bubble Rap on top of traditional ad hoc communication. This paper also proposes a concept of ranking to transfer messages to the node that has higher social centrality ranking compared to the current node. Nodes with varying social ranking are allowed to join piconets and forward messages based on Bubble Rap concept in scatternet environment. In BR algorithm, nodes forward messages to only those encountering nodes which are more popular than the current node
Development and characterization of efficient k-solubilizing rhizobacteria and mesorhizobial inoculants for chickpea
The use of mineral fertilizers has long been associated with the improved growth of crop plants as well as increased yield potential per unit area. However, the incessant practice of imbalanced fertilizers application has increased the economic and environmental costs for the agricultural sector. The deficiency of potassium (K) has been identified as a primary crop production challenge in certain semi-arid regions where soil-K reserves are increasingly being depleted. This study aimed to isolate and characterize K-solubilizing bacterial strains from the rhizosphere and root nodules of chickpea. Initially, 50 rhizobacterial strains and 50 rhizobial strains were isolated using Aleksandrovâs medium. Each of these collections was narrowed down to 25 strains, following a rigorous qualitative screening based on different physiological, morphological and biochemical tests. From these, five strains each of rhizosphere and nodule origins were selected based on qualitative as well quantitative determination of various growth promoting traits. In addition to efficient potassium and phosphate solubilization, the selected strains displayed better growth conditions, as evident by glucose substrate use at 25âŠC and pH 7. In this study, we found that strains SKB3 (rhizosphere) and JKR7 (rhizobia) were the most efficient K-solubilizers. Additionally, they possessed diverse plant growth promoting traits such as root colonization, the synthesis of siderophores, exopolysaccharides, chitinase activity, indole-acetic acid production and 1-aminocyclopropane-1-carboxylic acid deaminase activity. Overall, our results suggest that the application of bacterial K-solubilizers could be employed as a useful K-supplement in K-limited agroecosystems. Moreover, the use of these K-solubilizers may help lead in alleviating the negative environmental impacts associated with chemical fertilizer.I am very grateful to all of those with whom I have had the pleasure to work during this project, especially the Department of Soil and Environmental Sciences, College of Agriculture, University of Sargodha, Sargodha, Pakistan, the Soil & Water Sciences Department (SWD), Institute of Food and Agricultural Sciences (IFAS), University of Florida, USA, and the Higher Education Commission (HEC), Islamabad, Pakistan. Each of the members of the SWD, IFAS, University of Florida, USA, specifically L.Q. Ma, Letuzia Maria De Oliveira and Evandro Da Silva have provided me with extensive personal and professional guidance and have taught me a great deal about both scientific research and life in general during my six months stay there under International Research Support Initiative Program (IRSIP), HEC, Pakistan. The authors would also like to extend their sincere appreciation to the acknowledgment of the research supporting project (RSP-2021/95, King Saud University, Riyadh, Saudi Arabia)
Can Different Salt Formulations Revert the Depressing Effect of Salinity on Maize by Modulating Plant Biochemical Attributes and Activating Stress Regulators through Improved N Supply?
Salinity is a major constraint in improving agricultural productivity due to its adverse impact on various physiological and biochemical attributes of plants, and its effect on reducing nitrogen (N) use efficiency due to ion toxicity. To understand the relationship between sodium chloride (NaCl) and increased N application rates, a pot study was performed in which the ammonical (NH4+) form of N was applied as urea to maize crops at different rates (control, 160, 186, 240, 267, 293, and 320 kg N haâ1) using two salinity levels (control and 10 dS mâ1 NaCl). The results indicate that all biochemical and physiological attributes of the maize plant improved with increased concentration of N up to 293 kg haâ1, compared to those in the control treatment. Similarly, the optimal N concentration regulated the activities of antioxidant enzymes, i.e., catalase activity (CAT), peroxidase activity (POD), and superoxide dismutases (SOD), and also increased the N use efficiencies of the maize crop up to 293 kg N haâ1. Overall, our results show that the optimum level of N (293 kg haâ1) improved the salinity tolerance in the maize plant by activating stress coping physiological and biochemical mechanisms. This may have been due to the major role of N in the metabolic activity of plants and N assimilation enzymes activity such as nitrate reductase (NR) and nitrite reductase (NiR)
Evaluating socio-economic and environmental factors influencing farm-level water scarcity in Punjab, Pakistan
Pakistan's economy is primarily dependent on agriculture, but it faces serious water challenges. This paper critically evaluates the water resources and socioâeconomic and environmental factors contributing to increased farmâlevel water scarcity in the Punjab region. The study involved conducting structured interviews with 370 farmers to gather data necessary for conducting a detailed sociotechnical factor analysis. From this, eight factors were identified that were found to directly impact farmer wellâbeing including climate change (rise in temperature and erratic rainfall), poor socioâeconomic farmer conditions, issues linked to the warabandi (canal water distribution system), inadequate irrigation, reduced water availability, poor water course maintenance, and low adoption of efficient irrigation techniques. The KruskalâWallis test was then used to assess statistical differences between the respondents' demographic attributes and the identified factors. Demographic factors including age, education, land size, farming experience, and cultivated area showed significant mean differences with the eight factors. Young farmers with higher education levels were more likely to adopt highâefficiency irrigation systems to conserve water. The research also highlighted the importance of introducing crops with a lower water demand into the region and the need to proactively support agricultural extension services to encourage farmers to adopt more efficient irrigation systems to improve crop productivity and facilitate onâfarm water conservation
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