625 research outputs found
Temperature variation under continuous light restores tomato leaf photosynthesis and maintains the diurnal pattern in stomatal conductance
The response of tomato plants (Solanum lycopersicum L. cv. Aromata) to continuous light (CL) in relation to photosynthesis, abscisic acid (ABA) and reactive oxygen species (ROS) was investigated to improve the understanding of the development and/or alleviation of CL-induced leaf injury in constant and diurnal temperature fluctuations with similar daily light integral and daily mean temperature. The plants were grown in three photoperiodic treatments for 15 days; One treatment with a 16/8 h light/dark period and a light/dark temperature of 27/17°C (Control), two CL treatments with 24 h photoperiods, one with a constant temperature of 24°C (CLCT) and the other one with variable temperature of 27/17°C for 16/8 ho, respectively (CLVT). A diurnal pattern of stomatal conductance (gs) and [ABA] was observed in the plants grown in the control and CLVT conditions, while the plants in CLCT conditions experienced a significant decrease in stomatal conductance aligned with an increase in ABA. The net photosynthesis (A) was significantly reduced in CLCT, aligned with a significant decrease in the maximum rate of Rubisco carboxylation (Vcmax), the maximum rate of electron transport (Jmax) and mesophyll diffusion conductance to CO2 (gm) in comparison to the control and CLVT. An increased production of H2O2 and O2•- linked with increased activities of antioxidative enzymes was seen in both CL treatments, but despite of this, leaf injuries were only observed in the CLCT treatment. The results suggest that the diurnal temperature fluctuations alleviated the CL injury symptoms, probably because the diurnal cycles of cellular mechanisms were maintained. The ROS were shown not to be directly involved in CL-induced leaf injury, since both ROS production and scavenging was highest in CLVT without leaf chlorotic symptoms
Racial Differences in the Use of Most Commonly Performed Medical Procedures in the United States
Objective: This study investigates racial disparities in the use of commonly performed medical procedures in U.S. hospitals. Methods: To examine racial disparities, we calculated age-adjusted rate of procedures used by all Whites, Blacks, Hispanics, Asians or Pacific Islanders and Native Americans and calculated corresponding Relative Risks(RRs) of White vs. all other races based on procedure utilizations and insurance types using 20% random sample of Nationwide Inpatient Sample (NIS) data between 2001 and2003. Results: Whites were significantly more likely to receive 3 of the study procedures than Blacks, 3 of the procedures than Hispanics, 2 of the procedures than Asians or Pacific Islanders and 4 of the procedures than Native Americans (p\u3c0.05). We also found racial disparities to receive medical procedures based on patients’ insurance status.However, only in a few cases were these differences substantial. Conclusion: Race plays a significantly important role in the use of commonly performed medical procedures in U.S. hospitals
Continuous light increases growth, daily carbon gain, antioxidants, and alters carbohydrate metabolism in a cultivated and a wild tomato species
Cultivated tomato species develop leaf injury while grown in continuous light (CL). Growth, photosynthesis, carbohydrate metabolism and antioxidative enzyme activities of a cultivated (Solanum lycopersicum L. ‘Aromata’) and a wild tomato species (Solanum pimpinellifolium L.) were compared in this study aiming to analyse the species-specific differences and thermoperiod effects in responses to CL. The species were subjected to three photoperiodic treatments for 12 days in climate chambers: 16-h photoperiod with a light/dark temperature of 26/16ºC (P16D10 or control); CL with a constant temperature of 23ºC (P24D0); CL with a variable temperature of 26/16ºC (P24D10). The results showed that both species grown in CL had higher dry matter production due to the continuous photosynthesis and a subsequent increase in carbon gain. In S. lycopersicum, the rate of photosynthesis and the maximum photochemical efficiency of photosystem II declined in CL with the development of leaf chlorosis, reduction in the leaf chlorophyll content and a higher activity of antioxidative enzymes. The normal diurnal patterns of starch and sugar were only present under control conditions. The results demonstrated that CL conditions mainly affected the photosynthetic apparatus of a cultivated species (S. lycopersicum), and to a less degree to the wild species (S. pimpinellifolium). The negative effects of the CL could be alleviated by diurnal temperature variations, but the physiological mechanisms behind these are less clear. The results also show that the genetic potential for reducing the negative effects of CL does exist in the tomato germplasm
Review of Electric Vehicle Charging Technologies, Configurations, and Architectures
Electric Vehicles (EVs) are projected to be one of the major contributors to
energy transition in the global transportation due to their rapid expansion.
The EVs will play a vital role in achieving a sustainable transportation system
by reducing fossil fuel dependency and greenhouse gas (GHG) emissions. However,
high level of EVs integration into the distribution grid has introduced many
challenges for the power grid operation, safety, and network planning due to
the increase in load demand, power quality impacts and power losses. An
increasing fleet of electric mobility requires the advanced charging systems to
enhance charging efficiency and utility grid support. Innovative EV charging
technologies are obtaining much attention in recent research studies aimed at
strengthening EV adoption while providing ancillary services. Therefore,
analysis of the status of EV charging technologies is significant to accelerate
EV adoption with advanced control strategies to discover a remedial solution
for negative grid impacts, enhance desired charging efficiency and grid
support. This paper presents a comprehensive review of the current deployment
of EV charging systems, international standards, charging configurations, EV
battery technologies, architecture of EV charging stations, and emerging
technical challenges. The charging systems require a dedicated converter
topology, a control strategy and international standards for charging and grid
interconnection to ensure optimum operation and enhance grid support. An
overview of different charging systems in terms of onboard and off-board
chargers, AC-DC and DC-DC converter topologies, and AC and DC-based charging
station architectures are evaluated
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Multi-hazard groundwater risks to water supply from shallow depths: challenges to achieving the sustainable development goals in Bangladesh
Background: Groundwater currently provides 98% of all drinking-water supply in Bangladesh. Groundwater is found throughout Bangladesh but its quality (i.e. arsenic and salinity contamination) and quantity (i.e., water-storage depletion) vary across hydrological environments, posing unique challenges to certain geographical areas and population groups. Yet, no national-scale, multi-parameter groundwater hazard maps currently exist enabling water resources managers and policy makers to identify vulnerable areas to public health.
Methods: We develop, for the first time, groundwater multi-hazard maps at the national scale of Bangladesh combining information on arsenic, salinity and water storage. We apply geospatial techniques in ‘R’ programming language and ArcGIS environment, linking hydrological indicators for water quality and quantity to construct risk maps. A range of socio-economic variables including access to drinking and irrigation water supplies and social vulnerability (i.e., poverty) are overlaid on these risk maps to estimate exposures.
Results: Our multi-parameter groundwater hazard maps show that a considerable proportion of land area (5% to 24% under extremely-high to high risks) in Bangladesh is currently under combined risk of arsenic and salinity contamination, and groundwater-storage depletion. As small as 6.5 million (2.2 million poor) to 24.4 million (8.6 million poor) people are exposed to a combined risk of high arsenic, salinity and groundwater-storage depletion.
Conclusions: Our groundwater hazard maps reveal areas and exposure of population groups to water risks posed by arsenic and salinity contamination and depletion of water storage. These geospatial hazard maps can potentially guide policymakers in prioritizing mitigation and adaptation measures in order to achieve the United Nation’s Sustainable Development Goals across the water, agriculture and public health sectors in Bangladesh
Regeneration potential of seedling explants of chilli (Capsicum annuum)
A study was conducted with hypocotyl, cotyledon and shoot tip of chilli as explants for regeneration on MS medium supplemented with different concentrations and combinations of auxins and cytokinins. Regeneration potential was determined by two ways. One is regeneration of shoot via callus formation from hypocotyls and cotyledon explants; another was direct shoot regeneration from shoot tip explant. The highest callus was induced from hypocotyl in a combination of BAP (5.0 mgL-1) with NAA (0.1 mgL-1) and cotyledon in a combination of BAP (5.0 mgL-1) with IAA ((1.0 mgL-1). The callus induction as well as shoot initiation was higher in hypocotyls than cotyledon. Shoot tips regenerated into plantlets directly with sporadic small callus at the base. Shoot elongation was accelerated by using additional supplementation of GA3 and AgNO3. Regenerated shoots rooted best on the MS medium supplemented with 0.1 mg L-1 NAA + 0.05 mg L-1 IBA
CIAS detection of Fasciola hepatica/F. gigantica intermediate forms in bovines from Bangladesh
Fascioliasis is an important food-borne parasitic zoonosis caused by two trematode species, Fasciola hepatica and Fasciola gigantica. The characterisation and differentiation of Fasciola populations is crucial to control the disease, given the different transmission, epidemiology and pathology characteristics of the two species. Lineal biometric features of adult liver flukes infecting livestock have been studied to characterise and discriminate fasciolids from Bangladesh. An accurate analysis was conducted to phenotypically discriminate between fasciolids from naturally infected bovines (cattle, buffaloes) throughout the country. Morphometric analyses were made with a computer image analysis system (CIAS) applied on the basis of standardised measurements and the logistic model of the body growth and development of fasciolids in the different host groups. Since it is the first ever comprehensive study of this kind undertaken in Bangladesh, the results are compared to pure fasciolid populations of F. hepatica from the European Mediterranean area and F. gigantica from Burkina Faso, geographical areas where both species do not co-exist. Principal component analysis showed that the biometric characteristics of fasciolids from Bangladesh are situated between F. hepatica and F. gigantica standard populations, indicating the presence of phenotypes of intermediate forms in Bangladesh. These results are analysed by considering the present emergence of animal fascioliasis, the local lymnaeid fauna, the impact of climate change, and the risk of human infection in the country
Quality of service optimization in IoT driven intelligent transportation system
High mobility in ITS, especially V2V communication networks, allows increasing coverage and quick assistance to users and neighboring networks, but also degrades the performance of the entire system due to fluctuation in the wireless channel. How to obtain better QoS during multimedia transmission in V2V over future generation networks (i.e., edge computing platforms) is very challenging due to the high mobility of vehicles and heterogeneity of future IoT-based edge computing networks. In this context, this article contributes in three distinct ways: to develop a QoS-aware, green, sustainable, reliable, and available (QGSRA) algorithm to support multimedia transmission in V2V over future IoT-driven edge computing networks; to implement a novel QoS optimization strategy in V2V during multimedia transmission over IoT-based edge computing platforms; to propose QoS metrics such as greenness (i.e., energy efficiency), sustainability (i.e., less battery charge consumption), reliability (i.e., less packet loss ratio), and availability (i.e., more coverage) to analyze the performance of V2V networks. Finally, the proposed QGSRA algorithm has been validated through extensive real-time datasets of vehicles to demonstrate how it outperforms conventional techniques, making it a potential candidate for multimedia transmission in V2V over self-adaptive edge computing platforms
Pumping behavior of solar irrigation farmers for assessing the sustainability of groundwater in Bangladesh and India
The increasing use of Solar Irrigation Pumps (SIPs) has raised concerns about the overexploitation of groundwater. So, this study aims to evaluate the impact of SIPs on pumping behaviour of farmers and its subsequent effect on overall groundwater resources in Bangladesh and India. In Bangladesh, the study is being carried out in the intensively irrigated North-West region, where the government is promoting the feefor- service model for solar irrigation. This model creates a solar irrigation command area by setting up centralized sponsored SIPs. In India, the study is being conducted in the state of Gujarat, where the grid-connected solar irrigation pump model has been implemented under the Suryashakti Kisan Yojana (SKY) scheme
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