81 research outputs found
A novel EBG structure to improve isolation in MIMO antenna
25th Signal Processing and Communications Applications Conference, SIU 2017 -- 15 May 2017 through 18 May 2017 -- 128703A new, and advanced Electromagnetic Band Gap (EBG) structure is reported to reduce the mutual coupling between two tightly spaced rectangular patch antennas. The EBG structure provides more than 20 dB reduction in mutual coupling without degrading far-field patterns, gain, or bandwidth.IEEE Antennas & Propagation SocietyInstitute of Electrical and Electronics Engineers Inc.Ultra Safe Nuclear Corporatio
Research fatigue among injecting drug users in Karachi, Pakistan
Background
Karachi is the largest metropolis of Pakistan and its economic hub attracting domestic migrants for economic opportunities. It is also the epicenter of HIV epidemic in the country. Since 2004, one pilot study and four behavioral and biological surveillance rounds have been conducted in Karachi. In addition many student research projects have also focused on key risk groups including injection drug users (IDUs). As a result of this extra ordinary exposure of same kind of questions, IDUs know how to respond to high value questions related to sharing of needles or unsafe sexual practices. The purpose of the study was to explore the element of research fatigue among IDUs in Karachi, Pakistan. Methods
The study was conducted on 32 spots in Karachi, selected on the basis of estimate of IDUs at each spot. A trained field worker (recovered IDU) visited each spot; observed sharing behavior of IDUs and asked questions related to practices in January 2009. Verbal consent was obtained from each respondent before asking questions. Results
On average 14 IDUs were present at each spot and out of 32 selected spots, 81% were active while more than two groups were present at 69% spots. In each group three to four IDUs were present and everyone in the group was sharing. One dose of injecting narcotics was observed. Sharing of syringes, needles and distilled water was observed at 63% spots while professional injector/street doctor was present at 60% spots. Conclusion
There is a need to check internal consistency in surveillance research. It is highly likely that IDUs and other risk groups know how to respond to key questions but their responses do not match with the practices
The Carbon Emission Trading Policy of China: Does It Really Boost the Environmental Upgrading?
China’s rapid industrialization has led to massive resource consumption, and the country
has recently been highlighted as the World’s top carbon emitter. To pursue a sustainable economy
via environmental upgrading, reductions in carbon emission levels are of great concern. The carbon
emission reduction policy (CETP) is an environmental regulation aimed at cutting emissions and
achieving environmental protection. Based on panel data of pilot and non-pilot regions, this study
investigated the policy impact of the CETP on carbon emission reduction through difference-in differences (DID). The findings, based on pooled OLS (ordinary least squares) and LSDV (least
square dummy variable) regressions, revealed that the carbon emissions of the pilot regions (Beijing,
Tianjin, Shanghai, Guangdong, Chongqing, and Hubei) had reduced by 12 percent more than the
non-pilot regions. Thus, this implies that the CETP causes environmental upgrading. The results
were further verified using a number of robustness checks, including parallel trends, placebo test,
Granger causality test, and DID regression with a longer sample period. Based on the study findings,
it was concluded that to achieve higher upgrade levels related to the environment, the CETP needs to
be encouraged and improved for nationwide implementation. Furthermore, sustainable economic
development in China also needs strict environmental regulations and policy measures
Physiological and Biochemical Responses of Pepper (Capsicum annuum L.) Seedlings to Nickel Toxicity
Globally, heavy metal pollution of soil has remained a problem for food security and human health, having a significant impact on crop productivity. In agricultural environments, nickel (Ni) is becoming a hazardous element. The present study was performed to characterize the toxicity symptoms of Ni in pepper seedlings exposed to different concentrations of Ni. Four-week-old pepper seedlings were grown under hydroponic conditions using seven Ni concentrations (0, 10, 20, 30, 50, 75, and 100 mg L–1 NiCl2. 6H2O). The Ni toxicity showed symptoms, such as chlorosis of young leaves. Excess Ni reduced growth and biomass production, root morphology, gas exchange elements, pigment molecules, and photosystem function. The growth tolerance index (GTI) was reduced by 88-, 75-, 60-, 45-, 30-, and 19% in plants against 10, 20, 30, 50, 75, and 100 mg L–1 Ni, respectively. Higher Ni concentrations enhanced antioxidant enzyme activity, ROS accumulation, membrane integrity [malondialdehyde (MDA) and electrolyte leakage (EL)], and metabolites (proline, soluble sugars, total phenols, and flavonoids) in pepper leaves. Furthermore, increased Ni supply enhanced the Ni content in pepper’s leaves and roots, but declined nitrogen (N), potassium (K), and phosphorus (P) levels dramatically. The translocation of Ni from root to shoot increased from 0.339 to 0.715 after being treated with 10–100 mg L–1 Ni. The uptake of Ni in roots was reported to be higher than that in shoots. Generally, all Ni levels had a detrimental impact on enzyme activity and led to cell death in pepper seedlings. However, the present investigation revealed that Ni ≥ 30 mg L–1 lead to a deleterious impact on pepper seedlings. In the future, research is needed to further explore the mechanism and gene expression involved in cell death caused by Ni toxicity in pepper plants
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 (¯(〖lnRR〗^ ) =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 (¯(〖lnRR〗^ ) =3.375, 95% CI =3.323-3.428), alkaline soils (¯(〖lnRR〗^ ) =1.468, 95% CI =1.403-1.532), and acidic soils (¯(〖lnRR〗^ ) =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
Ameliorating drought effects in wheat using an exclusive or 2 co-applied rhizobacteria and ZnO nanoparticles
Simple Summary Wheat is a vital source of food, and its production is increasingly threatened by drought episodes. Moreover, its cultivation under water deficit situations along with zinc deficient soils is a major concern of declined wheat grain quantity and quality. Drought-linked changes in nutrient use efficiency, photosynthetic mechanisms, and chemical composition of wheat plants ultimately led to poorer harvest. Therefore, we aimed to understand the drought-ameliorating and grain nutritional improving effects in wheat by rhizobacteria (Azospirillum brasilense) and ZnO nanoparticles (NPs) under various growth stage-based drought stress episodes. Rhizobacteria colonized the host plant rhizosphere and provided growth promotion and stress amelioration. ZnO NPs were recognized as a potential water and zinc deficiency alleviator, and general growth promoter by triggering nitrogen metabolism, chlorophyll synthesis, membrane integrity, and grain zinc biofortification activities. Physio-biochemical observations indicated significantly higher positive effects under co-application over the sole use of either microbial or nanomaterials. Based on our research, it was concluded that co-applied Azospirillum brasilense and ZnO NPs generally increase wheat productivity under drought episodes with low operational cost to growers. Further, plausible synergistic physiological enhancement by NPs and rhizobacteria interaction may contribute towards sustainable wheat crop management under abiotic stresses. Drought is a major abiotic factor and affects cereal-based staple food production and reliability in developing countries such as Pakistan. To ensure a sustainable and consistent food supply, holistic production plans involving the integration of several drought mitigation approaches are required. Using a randomized complete block design strategy, we examined the drought-ameliorating characteristics of plant growth-promoting rhizobacteria (PGPR) and nanoparticles (NPs) exclusively or as a combined application (T-4) through three stages (D-1, D-2, and D-3) of wheat growth (T-1, control). Our field research revealed that Azospirillum brasilense alone (T-2) and zinc oxide NPs (T-3) improved wheat plant water relations, chlorophyll, proline, phenolics and grain quality, yield, and their allied traits over the stressed treatments. Specifically, the best outcome was observed in the combined treatment of PGPR and ZnO NPs (T-4). Interestingly, the combined treatment delivered effective drought mitigation through enhanced levels of antioxidants (15% APX, 27% POD, 35% CAT, 38% PPO and 44% SOD) over controls at the grain-filling stage (GFS, D-3 x T-1). The 40% improvements were recorded under the combined treatment at GFS over their respective controls. Their combined usage (PGPR and ZnO NPs) was concluded as an effective strategy for building wheat resilience under drought, especially in arid and semi-arid localities
Chemical priming enhances plant tolerance to salt stress
Salt stress severely limits the productivity of crop plants worldwide and its detrimental effects are aggravated by climate change. Due to a significant world population growth, agriculture has expanded to marginal and salinized regions, which usually render low crop yield. In this context, finding methods and strategies to improve plant tolerance against salt stress is of utmost importance to fulfill food security challenges under the scenario of the ever-increasing human population. Plant priming, at different stages of plant development, such as seed or seedling, has gained significant attention for its marked implication in crop salt-stress management. It is a promising field relying on the applications of specific chemical agents which could effectively improve plant salt-stress tolerance. Currently, a variety of chemicals, both inorganic and organic, which can efficiently promote plant growth and crop yield are available in the market. This review summarizes our current knowledge of the promising roles of diverse molecules/compounds, such as hydrogen sulfide (H2S), molecular hydrogen, nitric oxide (NO), hydrogen peroxide (H2O2), melatonin, chitosan, silicon, ascorbic acid (AsA), tocopherols, and trehalose (Tre) as potential primers that enhance the salinity tolerance of crop plants
Exploring potato seed research: a bibliometric approach towards sustainable food security
IntroductionPotato is considered to be complete food that will not only ensure food security but also alleviate poverty. Seed production of potato requires specific temperatures and conditions. In response to the growing emphasis on sustainable production, there has been an increasing focus on research on tuber seed production.MethodsIn our study, we have employed bibliometric analysis to investigate the trends in potato seed research and assess its correlation with sustainable development. Tabular analysis and network analysis are employed in the study to understand the prominent authors and institutions and research trends across time. For this purpose, Biblioshiny and Vosviewer software were used. The steps of bibliometric analysis were used, which included data retrieval from Dimensions software. Owing to its limitations, a major analysis was conducted without affecting the results.Result and discussionIt was found from the analysis that it was SDG 2 that was mostly linked with the theme of potato seed production. The results depicted an increasing trend of publications and citations. Co-authorship analysis of authors showed high linkage among groups of authors that formed clusters while other authors remained disconnected. Among countries United States, China and the United Kingdom had a higher impact on publications and citations. Our analysis showed that there is still scope for collaboration among countries as there is no evidence of multidisciplinary interlinkages. By understanding the current research landscape, identifying influential works and authors, and uncovering collaboration patterns, we can pave the way for future advancements in potato seed production. Ultimately, this research contributes to achieving sustainable agriculture and ensuring food security for future generations
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