EFFECTS OF INORGANIC NITROGEN AND PHOSPHORUS FERTILIZERS ON SELECTED SITES OF NATIVE GRASSLAND IN WESTERN CANADA

1965 ◽  
Vol 45 (3) ◽  
pp. 229-237 ◽  
Author(s):  
M. R. Kilcher ◽  
S. Smoliak ◽  
W. A. Hubbard ◽  
A. Johnston ◽  
A. T. H. Gross ◽  
...  
Keyword(s):  
Inorganic Nitrogen ◽  
Total Yield ◽  
First Year ◽  
Western Canada ◽  
Phosphorus Fertilizer ◽  
Nitrogen And Phosphorus ◽  
Native Grass ◽  
Yield Increase ◽  
Native Grassland ◽  
Better Than

N, P, and N + P at 60, 26, and 60 + 26 lb per acre were applied on native grass sites during three successive years at seven, locations in Western Canada. Single applications of the N fertilizer resulted in 3- or 4-year total yield increases of 300 to 600 lb per acre at six locations. At Summerland the 3-year increase was nearly 1400 lb. Phosphorus fertilizer by itself provided very little yield increase. N + P gave yield increases that were only slightly better than those from N alone.Residual responses to fertilizer were important, especially in the 12- to 16-in. rainfall locations. Only about one-third of the total yield increase occurred in the first year, with the remainder coming in the subsequent seasons.Weeds, where present, showed a marked response to fertilizer N in the first season; in subsequent years the response largely disappeared.

scholarly journals Impact of chemical and organic fertilizer on the yield and nutritional composition of bambara groundnut (Vigna subterranea L. Verdc.)

2019 ◽  
Vol 48 (4) ◽  
pp. 919-924
Author(s):  
Mahmudul Hasan ◽  
Md Kamal Uddin ◽  
Mahmud Tengku Muda Mohammad ◽  
Ali Tan Kee Zuan ◽  
Motmainna
Keyword(s):  
Organic Fertilizer ◽  
Nutritional Composition ◽  
Bambara Groundnut ◽  
Vigna Subterranea ◽  
Phosphorus Fertilizer ◽  
Nitrogen And Phosphorus ◽  
100 Seed Weight ◽  
Different Doses ◽  
P Fertilizers ◽  
Better Than

A pot experiment was conducted to find out the effects of chemical and organic fertilizer on the yield and nutritional composition of bambara groundnut (Vigna subterranea). The size of the pot was 65.94 cm2. Different rates of compost, biofertilizer, gypsum was used along with the combination of different doses of nitrogen and phosphorus fertilizer. N and P fertilizers were found to play dominating role to increase yield and nutritional composition of the plant. Number of pod (41.75), 100-seed weight (34.25 g), protein (22.15%), Ca (803.25 mg/ka) increased with the application of N and P 30 and 60 kg/ha, respectively which was better than all other treatments. The application of N30 + P60 kg/ha increased yield and nutritional composition of bambara groundnut.

A Cohort study to compare Admission criteria and Academic performance among preclinical students at The Copperbelt University School of Medicine: complete enumeration (Preprint)

2019 ◽  
Author(s):  
Andrew Mwila
Keyword(s):  
Academic Performance ◽  
Cohort Study ◽  
Clinical Medicine ◽  
Average Score ◽  
First Year ◽  
Admission Criteria ◽  
Biomedical Sciences ◽  
Dental Surgery ◽  
School Of Medicine ◽  
Better Than

BACKGROUND The Copperbelt University is the second public University in Zambia. The School of Medicine has four major programs namely; Bachelor of Medicine and Surgery, Bachelor of Dental Surgery, Bachelor of Clinical Medicine and Bachelor of Biomedical sciences. The Copperbelt University School of Medicine runs a five-year training program for both the BDS and the MBCHB programs. Students are admitted into the Medical school after successfully completing their first year at the Main campus in the School of Natural Sciences with an average of 4 B grades or higher (B grade is a mark of 65 to 74%). OBJECTIVE The study was done to determine the association between admission criteria and academic performance among preclinical students. Hence, the study compares the academic performance among preclinical students admitted into the Bachelor of Dental Surgery and Bachelor of Medicine and Surgery at the Copperbelt University School of Medicine. METHODS This is a retrospective cohort study conducted at Michael Chilufya Sata School of medicine Campus. A pilot study was conducted with 30 BDS and 30 MBCHB students and the obtained information helped determine the sample size. SPSS was used to analyze the data. The study period lasted approximately 7 weeks at a cost of K1621. RESULTS In 2014, there was an improvement in average performance between 2nd and 3rd year for each program. An average score of 15.4 (SD 4.2) was obtained in 3rd year compared to 12.8 (SD 4.9) in 2nd year (p<0.001). Meanwhile, 3rd MB ChB mean score was 12.6 (SD 3.7) compared to 10.7 (SD 3.6) in 2nd years (p<0.05). However, in 2016, both programs, 3rd year mean scores were lower than 2nd year (MB ChB 2nd year mean score was 12.0 (SD 4.3) compared to 3rd year with a mean score of 9.5 (SD 4.5), p<0.001; BDS 2nd year mean score was 10.6 (SD 4.0) compared to 3rd year mean score of 8.2 (SD 3.4), p<0.01. On average MB ChB students performed better than BDS students in all the years (p<0.05), except in 2016 when the results were comparable. CONCLUSIONS Results from the study shows that entry criteria has a correlation to academic performance as students admitted with higher grades perform much better than those with lower grades.

scholarly journals LED Lighting and High-Density Planting Enhance the Cost-Efficiency of Halimione portulacoides Extraction Units for Integrated Aquaculture

2021 ◽  
Vol 11 (11) ◽  
pp. 4995
Author(s):  
Marco Custódio ◽  
Paulo Cartaxana ◽  
Sebastián Villasante ◽  
Ricardo Calado ◽  
Ana Isabel Lillebø
Keyword(s):  
Plant Density ◽  
Inorganic Nitrogen ◽  
High Density ◽  
Planting Density ◽  
Nitrogen And Phosphorus ◽  
Integrated Aquaculture ◽  
Halimione Portulacoides ◽  
White Leds ◽  
Artificial Lighting ◽  
Aquaculture Effluents

Halophytes are salt-tolerant plants that can be used to extract dissolved inorganic nutrients from saline aquaculture effluents under a production framework commonly known as Integrated Multi-Trophic Aquaculture (IMTA). Halimione portulacoides (L.) Aellen (common name: sea purslane) is an edible saltmarsh halophyte traditionally consumed by humans living near coastal wetlands and is considered a promising extractive species for IMTA. To better understand its potential for IMTA applications, the present study investigates how artificial lighting and plant density affect its productivity and capacity to extract nitrogen and phosphorous in hydroponic conditions that mimic aquaculture effluents. Plant growth was unaffected by the type of artificial lighting employed—white fluorescent lights vs. blue-white LEDs—but LED systems were more energy-efficient, with a 17% reduction in light energy costs. Considering planting density, high-density units of 220 plants m−2 produced more biomass per unit of area (54.0–56.6 g m−2 day−1) than did low-density units (110 plants m−2; 34.4–37.1 g m−2 day−1) and extracted more dissolved inorganic nitrogen and phosphorus. Overall, H. portulacoides can be easily cultivated hydroponically using nutrient-rich saline effluents, where LEDs can be employed as an alternative to fluorescent lighting and high-density planting can promote higher yields and extraction efficiencies.

scholarly journals Deep learning for intelligent diagnosis in thyroid scintigraphy

2021 ◽  
Vol 49 (1) ◽  
pp. 030006052098284
Author(s):  
Tingting Qiao ◽  
Simin Liu ◽  
Zhijun Cui ◽  
Xiaqing Yu ◽  
Haidong Cai ◽  
...  
Keyword(s):  
Deep Learning ◽  
Disease Diagnosis ◽  
Kappa Coefficient ◽  
Diagnostic Assessment ◽  
First Year ◽  
Thyroid Scintigraphy ◽  
Diagnostic Ability ◽  
The Third ◽  
Classification Time ◽  
Better Than

Objective To construct deep learning (DL) models to improve the accuracy and efficiency of thyroid disease diagnosis by thyroid scintigraphy. Methods We constructed DL models with AlexNet, VGGNet, and ResNet. The models were trained separately with transfer learning. We measured each model’s performance with six indicators: recall, precision, negative predictive value (NPV), specificity, accuracy, and F1-score. We also compared the diagnostic performances of first- and third-year nuclear medicine (NM) residents with assistance from the best-performing DL-based model. The Kappa coefficient and average classification time of each model were compared with those of two NM residents. Results The recall, precision, NPV, specificity, accuracy, and F1-score of the three models ranged from 73.33% to 97.00%. The Kappa coefficient of all three models was >0.710. All models performed better than the first-year NM resident but not as well as the third-year NM resident in terms of diagnostic ability. However, the ResNet model provided “diagnostic assistance” to the NM residents. The models provided results at speeds 400 to 600 times faster than the NM residents. Conclusion DL-based models perform well in diagnostic assessment by thyroid scintigraphy. These models may serve as tools for NM residents in the diagnosis of Graves’ disease and subacute thyroiditis.

scholarly journals Feedback Regulation between Aquatic Microorganisms and the Bloom-Forming Cyanobacterium Microcystis aeruginosa

2019 ◽  
Vol 85 (21) ◽  
Author(s):  
Meng Zhang ◽  
Tao Lu ◽  
Hans W. Paerl ◽  
Yiling Chen ◽  
Zhenyan Zhang ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Microcystis Aeruginosa ◽  
Lake Taihu ◽  
Inorganic Nitrogen ◽  
Microbial Community Composition ◽  
Nitrogen And Phosphorus ◽  
Content Type ◽  
Coculture System ◽  
Eukaryotic Microorganisms ◽  
Aquatic Microorganisms

ABSTRACT The frequency and intensity of cyanobacterial blooms are increasing worldwide. Interactions between toxic cyanobacteria and aquatic microorganisms need to be critically evaluated to understand microbial drivers and modulators of the blooms. In this study, we applied 16S/18S rRNA gene sequencing and metabolomics analyses to measure the microbial community composition and metabolic responses of the cyanobacterium Microcystis aeruginosa in a coculture system receiving dissolved inorganic nitrogen and phosphorus (DIP) close to representative concentrations in Lake Taihu, China. M. aeruginosa secreted alkaline phosphatase using a DIP source produced by moribund and decaying microorganisms when the P source was insufficient. During this process, M. aeruginosa accumulated several intermediates in energy metabolism pathways to provide energy for sustained high growth rates and increased intracellular sugars to enhance its competitive capacity and ability to defend itself against microbial attack. It also produced a variety of toxic substances, including microcystins, to inhibit metabolite formation via energy metabolism pathways of aquatic microorganisms, leading to a negative effect on bacterial and eukaryotic microbial richness and diversity. Overall, compared with the monoculture system, the growth of M. aeruginosa was accelerated in coculture, while the growth of some cooccurring microorganisms was inhibited, with the diversity and richness of eukaryotic microorganisms being more negatively impacted than those of prokaryotic microorganisms. These findings provide valuable information for clarifying how M. aeruginosa can potentially modulate its associations with other microorganisms, with ramifications for its dominance in aquatic ecosystems. IMPORTANCE We measured the microbial community composition and metabolic responses of Microcystis aeruginosa in a microcosm coculture system receiving dissolved inorganic nitrogen and phosphorus (DIP) close to the average concentrations in Lake Taihu. In the coculture system, DIP is depleted and the growth and production of aquatic microorganisms can be stressed by a lack of DIP availability. M. aeruginosa could accelerate its growth via interactions with specific cooccurring microorganisms and the accumulation of several intermediates in energy metabolism-related pathways. Furthermore, M. aeruginosa can decrease the carbohydrate metabolism of cooccurring aquatic microorganisms and thus disrupt microbial activities in the coculture. This also had a negative effect on bacterial and eukaryotic microbial richness and diversity. Microcystin was capable of decreasing the biomass of total phytoplankton in aquatic microcosms. Overall, compared to the monoculture, the growth of total aquatic microorganisms is inhibited, with the diversity and richness of eukaryotic microorganisms being more negatively impacted than those of prokaryotic microorganisms. The only exception is M. aeruginosa in the coculture system, whose growth was accelerated.

scholarly journals An analysis of Italian university students’ performance through segmented regression models: gender differences in STEM courses

Genus ◽  
2021 ◽  
Vol 77 (1) ◽  
Author(s):  
Andrea Priulla ◽  
Nicoletta D’Angelo ◽  
Massimo Attanasio
Keyword(s):  
Gender Differences ◽  
Regression Models ◽  
First Year ◽  
Strongly Correlated ◽  
Segmented Regression ◽  
Freshmen Students ◽  
Female Performance ◽  
And Mathematics ◽  
The Relationship ◽  
Better Than

AbstractThis paper investigates gender differences in university performances in Science, Technology, Engineering and Mathematics (STEM) courses in Italy, proposing a novel application through the segmented regression models. The analysis concerns freshmen students enrolled at a 3-year STEM degree in Italian universities in the last decade, with a focus on the relationship between the number of university credits earned during the first year (a good predictor of the regularity of the career) and the probability of getting the bachelor degree within 4 years. Data is provided by the Italian Ministry of University and Research (MIUR). Our analysis confirms that first-year performance is strongly correlated to obtaining a degree within 4 years. Furthermore, our findings show that gender differences vary among STEM courses, in accordance with the care-oriented and technical-oriented dichotomy. Males outperform females in mathematics, physics, chemistry and computer science, while females are slightly better than males in biology. In engineering, female performance seems to follow the male stream. Finally, accounting for other important covariates regarding students, we point out the importance of high school background and students’ demographic characteristics.

Bacterioplankton, Phytoplankton, and Zooplankton Communities in a British Columbia Coastal Lake Before and After Nutrient Reduction

1986 ◽  
Vol 43 (8) ◽  
pp. 1504-1514 ◽  
Author(s):  
F. Joan Hardy ◽  
Ken S. Shortreed ◽  
John G. Stockner
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Inorganic Nitrogen ◽  
Size Fraction ◽  
Growing Season ◽  
Nutrient Reduction ◽  
Nitrogen And Phosphorus ◽  
Coastal Lake ◽  
Before And After ◽  
High Concentrations

Inorganic nitrogen and phosphorus were applied weekly during the growing season from 1980 to 1982 and twice weekly in 1983 to Hobiton Lake, a warm monomictic coastal lake in British Columbia. The lake was not fertilized in 1984. Average numbers of bacteria during the growing season decreased from a high of 1.53 × 106∙mL−1 in the fertilized condition to 0.84 × 106∙mL−1 in the unfertilized condition. Chlorophyll a concentrations decreased from a maximum seasonal average of 2.69 μg∙L−1 (1981) to 1.30 μg∙L−1 (1984), and algal numbers decreased from 5.83 × 104∙mL−1 (1983) to 2.29 × 104∙mL−1 (1984). Although the numbers of phytoplankton in each size fraction (picoplankton, nanoplankton, or microplankton) decreased in the unfertilized condition, the greatest change was an almost fourfold decrease in picoplankton, which consisted of 90% cyanobacteria (primarily Synechococcus spp.). Abundance of the large diatoms Rhizosolenia spp. and Melosira spp. increased in 1984, resulting in an increase in average seasonal algal volume. Average densities of medium (0.15–0.84 mm) and large (0.85–1.5 mm) zooplankton were greatest in 1982, while rotifers and small zooplankton (0.10–0.14 mm) were most dense in 1984 following nutrient reduction. The lake had relatively high concentrations of planktivorous juvenile sockeye salmon (Oncorhynchus nerka) that appeared to minimize any direct effect of nutrient additions on zooplankton densities.

scholarly journals Alterations in microbial community composition with increasing <i>f</i>CO<sub>2</sub>: a mesocosm study in the eastern Baltic Sea

2017 ◽  
Vol 14 (16) ◽  
pp. 3831-3849 ◽  
Author(s):  
Katharine J. Crawfurd ◽  
Santiago Alvarez-Fernandez ◽  
Kristina D. A. Mojica ◽  
Ulf Riebesell ◽  
Corina P. D. Brussaard
Keyword(s):  
Microbial Community ◽  
Ocean Acidification ◽  
Baltic Sea ◽  
Community Dynamics ◽  
Inorganic Nitrogen ◽  
Microbial Community Composition ◽  
Cell Diameter ◽  
Viral Lysis ◽  
Nitrogen And Phosphorus ◽  
Eastern Baltic

Abstract. Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO2) by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO2 scenarios. All six groups of phytoplankton enumerated by flow cytometry ( <  20 µm cell diameter) showed distinct trends in net growth and abundance with CO2 enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, Synechococcus and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO2 (fCO2). Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing fCO2 sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of fCO2 on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing fCO2, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.

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