Consumption of nutrient rich foods such as beans and peas is recommended because these foods provide key nutrients and relatively little energy. Many consumers are unfamiliar with dried beans or do not have the time t...Consumption of nutrient rich foods such as beans and peas is recommended because these foods provide key nutrients and relatively little energy. Many consumers are unfamiliar with dried beans or do not have the time to prepare them. The purpose of this study was to compare nutrient density and nutrient-to-cost among dried cooked, canned (liquid and solids), and canned/drained black, garbanzo, kidney, lima, pinto, white beans, and black-eyed peas. Prices were obtained from 60 grocery stores in January 2009. Nutrient content per 100 g was calculated using the U.S. Department of Agriculture Nutrient Database for Standard Reference, Release 22, and Nutrition Data System for Research (for canned/drained). Nutrient density scores were estimated using the Nutrient Rich Food Index 9.3 (NRF9.3). Nutrient-to-cost ratio (NTCR) was computed as the NRF 9.3 score (per 100 kcal) divided by the cost per half-cup servings per package (12) or per can (3.5). Compared to canned beans, dried cooked beans were significantly more energy dense, contained more protein, fiber, iron, potassium and magnesium;and less sodium than canned beans (p < 0.05 for all). Canned/drained beans contained more sodium than cooked beans (p < 0.05). NRF9.3 scores were 7.3, 2.8, and 4.8 for cooked, canned, and canned/drained beans, respectively. NTCR for cooked, canned, and canned/drained beans was 63.4, 8.9, and 15.2, respectively. Results highlight the benefits of choosing dried beans and also illustrate that canned beans, when drained, provide a healthy alternative. Beans, regardless of type/form, are a nutrient rich food and should be encouraged as part of an overall healthy diet.展开更多
The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an important mechanism of resistance to antibiotics, usual...The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an important mechanism of resistance to antibiotics, usually confers a fitness cost in bacteria. In this study, we aimed to determine why antibiotic resistance conferred by overexpression of an efflux pump persisted in low-nutrient environments(TOC < 10 mg/L) such as drinking and source water in which antibiotic selective pressure might be very low or even absent.Competition experiments between wild-type Pseudomonas aeruginosa and ciprofloxacinresistant mutants revealed that the fitness cost of ciprofloxacin resistance significantly decreased(p < 0.05) under low-nutrient(0.5 mg/L total organic carbon(TOC)) relative to high-nutrient(500 mg/L TOC) conditions. Mechanisms underlying this fitness cost were analyzed. The mexD gene expression in resistant bacteria(cip3 strain) was significantly lower(p < 0.05) in low-nutrient conditions, with 10 mg/L TOC((8.01 ± 0.82)-fold), than in high-nutrient conditions, with 500 mg/L TOC((48.89 ± 4.16)-fold). Moreover, rpoS gene expression in resistant bacteria((1.36 ± 0.13)-fold) was significantly lower(p < 0.05) than that in the wild-type strain((2.78 ± 0.29)-fold) under low-nutrient conditions(10 mg/L TOC),suggesting a growth advantage. Furthermore, the difference in metabolic activity between the two competing strains was significantly smaller(p < 0.05) in low-nutrient conditions(5 and 0.5 mg/L TOC). These results suggest that nutrient levels are a key factor in determining the persistence of antibiotic resistance conferred by efflux pumps in the natural environment with trace amounts or no antibiotics.展开更多
A full-scale oxidation ditch process for treating sewage was simulated with the ASM2d model and optimized for minimal cost with acceptable performance in terms of ammonium and phosphorus removal. A unified index was i...A full-scale oxidation ditch process for treating sewage was simulated with the ASM2d model and optimized for minimal cost with acceptable performance in terms of ammonium and phosphorus removal. A unified index was introduced by integrating operational costs （aeration energy and sludge production） with effluent violations for performance evaluation. Scenario analysis showed that, in comparison with the baseline （all of the 9 aerators activated）, the strategy of activating 5 aerators could save aeration energy significantly with an ammonium violation below 10%. Sludge discharge scenario analysis showed that a sludge discharge flow of 250- 300 ma/day （solid retention time （SRT）, 13-15 days） was appropriate for the enhancement of phosphorus removal without excessive sludge production. The proposed optimal control strategy was： activating 5 rotating disks operated with a mode of ＂111100100＂ （ ＂1＂ represents activation and ＂0＂ represents inactivation） for aeration and sludge discharge flow of 200 m3/day （SRT, 19 days）. Compared with the baseline, this strategy could achieve ammonium violation below 10% and TP violation below 30% with substantial reduction of aeration energy cost （46%） and minimal increment of sludge production （〈 2%）. This study provides a useful approach for the optimization of process operation and control.展开更多
Field trials were conducted to determine the economically optimum fertilizer rates for soybean production and for optimizing net profits in Dedza, Lilongwe and Salima Districts of Malawi. The effects of PK fertilizer ...Field trials were conducted to determine the economically optimum fertilizer rates for soybean production and for optimizing net profits in Dedza, Lilongwe and Salima Districts of Malawi. The effects of PK fertilizer rates on rain use efficiency (RUE), harvest index, agronomic use efficiency of phosphorous (AEP) and potassium (AEK), and value cost ratio (VCR) were evaluated. The applied diagnostic PK fertilizer rates significantly improved soybean grain yields, harvest index, rainwater use efficiency, AEP, AEK and returns to fertilizer use expressed as value cost ratio (VCR). However, the results differed significantly展开更多
This study was executed to offer the basis for optimized profit from fertilizer use for sorghum yield and to determine robust crop nutrient response function and economic rate for the production of sorghum at Miesso C...This study was executed to offer the basis for optimized profit from fertilizer use for sorghum yield and to determine robust crop nutrient response function and economic rate for the production of sorghum at Miesso Central Rift Valley of Ethiopia. Trails were conducted at six experimental sites, sorghum yield response to N and P fertilizers application and economically optimum rates of nitrogen (EONR) and phosphorus (EOPR) were evaluated on a vertisols within the semi-arid Miesso districts west Hararge zone of Oromia region. The nutrient rates in 2014 cropping season four levels of Nitrogen (N) alone, these levels with 20 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> Phosphorus (P) and without N, 69 kg<span style="white-space:nowrap;">·</span>ha<sup><span style="white-space:nowrap;">−</span>1</sup> N with three levels of P treatments including the zero control were evaluated. In 2015, cropping season similar rates of N alone, the same rate N with 20 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> P, 92 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> N with three rates of P including the zero control were evaluated. The treatments were arranged in a randomized complete block with three replications in factorial design. Nutrient responses of sorghum were determined using asymptotic quadratic plateau functions. The significantly highest nitrogen rate was 46 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> alone in 2014 season, which gave grain yield of 2.56 Mg<span style="white-space:nowrap;">·ha<sup>−1</sup></span><sup> </sup>with a maximum yield advantage of 43%. P rates in both seasons and combined (sites + seasons) were not significantly influenced sorghum yield. Nitrogen agronomic and partial factor productivity peaked at 23 kg N <span style="white-space:nowrap;">ha<sup>−1</sup></span> but declined with increasing N rate. The EONR combined (sites + seasons) were 37, 45, 52 and 60 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span><sup> </sup>and for the profit to cost ratio (PCR) were 2.43, 3.65, 4.86 and 5.79 at difference cost to grain price ratios (CP) = 3.6, 2.3, 1.6 and 1.2 respectively at Miesso Ethiopia. Nitrogen application had economically profitable than P. The study concluded that the application of N at 37 or 60 kg N <span style="white-space:nowrap;">ha<sup>−1</sup></span> to sorghum production could be economically profitable for those economically constrained farmers or economically not constrained farmers. Validation should be farther conducted on farmers’ fields for refining the results obtained.展开更多
Models predicting optimal levels of plant defense against herbivores typically include two assumptions: 1) defense is both beneficial and costly;and 2) the relationship between costs and benefits of a defense is consi...Models predicting optimal levels of plant defense against herbivores typically include two assumptions: 1) defense is both beneficial and costly;and 2) the relationship between costs and benefits of a defense is consistent across environments. However, the expression of costs and benefits of defense may be environmentally dependent. We examined lines of Brassica rapa, previously divergently selected for the defensive trait foliar glucosinolate content. In one set of experiments (Experiment #1), plants were grown in herbivore-free and herbivore-present environments to investigate the costs and benefits of this defense. In a second set of experiments (Experiment #2), plants were grown at two nutrient levels and two temperatures to examine the environmental context of costs of defense. In Experiment #1, increased levels of damage resulted in decreased flower production and plants from high glucosinolate lines received less damage than those from low glucosinolate lines, suggesting a benefit of this defense. In this experiment no cost of defense was detected. In Experiment #2, nutrients had a significant positive effect on flower production at 23°C, but not at 32°C. No significant effects of glucosinolate line nor interaction between nutrient environment and glucosinolate line were detected at 23°C, suggesting that no cost of defense occurred at this lower temperature. Similarly, no significant nutrient environment by glucosenolate line interaction was detected at 32°C. However, a significant effect of glucosinolate line was observed suggesting that at 32°C costs were incurred, but nutrient environment had no mitigating effect. While results from Experiment #1 suggested that defense was beneficial, but not costly, results from Experiment #2 suggested that costs of defense were temperature dependent. For species occupying broad geographic ranges, these findings of temperature-dependent costs are especially insightful with regard to the evolution of defense because differing geographic populations are likely to experience differing temperature environments.展开更多
为定量化设施果类蔬菜养分投入,实现设施果蔬优质高产、绿色高效生产,本研究以山东省典型设施果类蔬菜为研究对象,基于通过农户调研与土壤样品采集测定收集的数据,结合对现有文献的综述,使用生命周期评价方法,系统分析研究区域设施果类...为定量化设施果类蔬菜养分投入,实现设施果蔬优质高产、绿色高效生产,本研究以山东省典型设施果类蔬菜为研究对象,基于通过农户调研与土壤样品采集测定收集的数据,结合对现有文献的综述,使用生命周期评价方法,系统分析研究区域设施果类蔬菜生产的施肥现状、土壤养分状况和环境代价及其相关关系。结果表明:山东省主栽设施果类蔬菜养分投入量高,设施番茄、黄瓜、辣椒、茄子的氮(以N计)、磷(以P2O5计)、钾(以K2O计)投入量平均达到743、600、740 kg·hm^(-2),施肥变异系数较大(CV=30.3%~43.9%),大量的肥料投入造成了较高的养分盈余,进而导致表层土壤(0~30 cm)养分含量显著升高,同时导致了较高的环境代价。设施果类蔬菜的单位面积上活性氮损失、温室气体排放、富营养化效应和酸化效应均以黄瓜生产系统最高,分别达225 kg·hm^(-2)、10058 kg CO_(2e)·hm^(-2)、124 kg PO_(4e)·hm^(-2)和63.4 kg SO_(2e)·hm^(-2),其次是茄子、番茄和辣椒。氮素盈余是导致活性氮损失的最主要因素,氮、磷、钾肥料的生产过程和施用过程是设施果类蔬菜温室气体排放、富营养化效应和酸化效应的主要贡献因子,贡献率高达80%以上。因此,为保证设施果类蔬菜产业绿色优质高质量发展,应通过优化设施蔬菜养分资源综合管理策略来减少养分盈余、降低环境代价。展开更多
文摘Consumption of nutrient rich foods such as beans and peas is recommended because these foods provide key nutrients and relatively little energy. Many consumers are unfamiliar with dried beans or do not have the time to prepare them. The purpose of this study was to compare nutrient density and nutrient-to-cost among dried cooked, canned (liquid and solids), and canned/drained black, garbanzo, kidney, lima, pinto, white beans, and black-eyed peas. Prices were obtained from 60 grocery stores in January 2009. Nutrient content per 100 g was calculated using the U.S. Department of Agriculture Nutrient Database for Standard Reference, Release 22, and Nutrition Data System for Research (for canned/drained). Nutrient density scores were estimated using the Nutrient Rich Food Index 9.3 (NRF9.3). Nutrient-to-cost ratio (NTCR) was computed as the NRF 9.3 score (per 100 kcal) divided by the cost per half-cup servings per package (12) or per can (3.5). Compared to canned beans, dried cooked beans were significantly more energy dense, contained more protein, fiber, iron, potassium and magnesium;and less sodium than canned beans (p < 0.05 for all). Canned/drained beans contained more sodium than cooked beans (p < 0.05). NRF9.3 scores were 7.3, 2.8, and 4.8 for cooked, canned, and canned/drained beans, respectively. NTCR for cooked, canned, and canned/drained beans was 63.4, 8.9, and 15.2, respectively. Results highlight the benefits of choosing dried beans and also illustrate that canned beans, when drained, provide a healthy alternative. Beans, regardless of type/form, are a nutrient rich food and should be encouraged as part of an overall healthy diet.
基金supported by the National Natural Science Foundation of China(Nos.51708534,51678551,and 51478450)the National Key Research and Development Program of China-International collaborative project from the Ministry of Science and Technology(No.2017YFE0107300)+1 种基金the Xiamen Major Science and Technology Project(No.3502Z20171003)K.C.Wong Education Foundation
文摘The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an important mechanism of resistance to antibiotics, usually confers a fitness cost in bacteria. In this study, we aimed to determine why antibiotic resistance conferred by overexpression of an efflux pump persisted in low-nutrient environments(TOC < 10 mg/L) such as drinking and source water in which antibiotic selective pressure might be very low or even absent.Competition experiments between wild-type Pseudomonas aeruginosa and ciprofloxacinresistant mutants revealed that the fitness cost of ciprofloxacin resistance significantly decreased(p < 0.05) under low-nutrient(0.5 mg/L total organic carbon(TOC)) relative to high-nutrient(500 mg/L TOC) conditions. Mechanisms underlying this fitness cost were analyzed. The mexD gene expression in resistant bacteria(cip3 strain) was significantly lower(p < 0.05) in low-nutrient conditions, with 10 mg/L TOC((8.01 ± 0.82)-fold), than in high-nutrient conditions, with 500 mg/L TOC((48.89 ± 4.16)-fold). Moreover, rpoS gene expression in resistant bacteria((1.36 ± 0.13)-fold) was significantly lower(p < 0.05) than that in the wild-type strain((2.78 ± 0.29)-fold) under low-nutrient conditions(10 mg/L TOC),suggesting a growth advantage. Furthermore, the difference in metabolic activity between the two competing strains was significantly smaller(p < 0.05) in low-nutrient conditions(5 and 0.5 mg/L TOC). These results suggest that nutrient levels are a key factor in determining the persistence of antibiotic resistance conferred by efflux pumps in the natural environment with trace amounts or no antibiotics.
基金supported by the National Natural Science Foundation of China (No.20921140094)the Chinese Academy of Sciences (No.KZCX2-YW-JC407)
文摘A full-scale oxidation ditch process for treating sewage was simulated with the ASM2d model and optimized for minimal cost with acceptable performance in terms of ammonium and phosphorus removal. A unified index was introduced by integrating operational costs （aeration energy and sludge production） with effluent violations for performance evaluation. Scenario analysis showed that, in comparison with the baseline （all of the 9 aerators activated）, the strategy of activating 5 aerators could save aeration energy significantly with an ammonium violation below 10%. Sludge discharge scenario analysis showed that a sludge discharge flow of 250- 300 ma/day （solid retention time （SRT）, 13-15 days） was appropriate for the enhancement of phosphorus removal without excessive sludge production. The proposed optimal control strategy was： activating 5 rotating disks operated with a mode of ＂111100100＂ （ ＂1＂ represents activation and ＂0＂ represents inactivation） for aeration and sludge discharge flow of 200 m3/day （SRT, 19 days）. Compared with the baseline, this strategy could achieve ammonium violation below 10% and TP violation below 30% with substantial reduction of aeration energy cost （46%） and minimal increment of sludge production （〈 2%）. This study provides a useful approach for the optimization of process operation and control.
文摘Field trials were conducted to determine the economically optimum fertilizer rates for soybean production and for optimizing net profits in Dedza, Lilongwe and Salima Districts of Malawi. The effects of PK fertilizer rates on rain use efficiency (RUE), harvest index, agronomic use efficiency of phosphorous (AEP) and potassium (AEK), and value cost ratio (VCR) were evaluated. The applied diagnostic PK fertilizer rates significantly improved soybean grain yields, harvest index, rainwater use efficiency, AEP, AEK and returns to fertilizer use expressed as value cost ratio (VCR). However, the results differed significantly
文摘This study was executed to offer the basis for optimized profit from fertilizer use for sorghum yield and to determine robust crop nutrient response function and economic rate for the production of sorghum at Miesso Central Rift Valley of Ethiopia. Trails were conducted at six experimental sites, sorghum yield response to N and P fertilizers application and economically optimum rates of nitrogen (EONR) and phosphorus (EOPR) were evaluated on a vertisols within the semi-arid Miesso districts west Hararge zone of Oromia region. The nutrient rates in 2014 cropping season four levels of Nitrogen (N) alone, these levels with 20 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> Phosphorus (P) and without N, 69 kg<span style="white-space:nowrap;">·</span>ha<sup><span style="white-space:nowrap;">−</span>1</sup> N with three levels of P treatments including the zero control were evaluated. In 2015, cropping season similar rates of N alone, the same rate N with 20 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> P, 92 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> N with three rates of P including the zero control were evaluated. The treatments were arranged in a randomized complete block with three replications in factorial design. Nutrient responses of sorghum were determined using asymptotic quadratic plateau functions. The significantly highest nitrogen rate was 46 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span> alone in 2014 season, which gave grain yield of 2.56 Mg<span style="white-space:nowrap;">·ha<sup>−1</sup></span><sup> </sup>with a maximum yield advantage of 43%. P rates in both seasons and combined (sites + seasons) were not significantly influenced sorghum yield. Nitrogen agronomic and partial factor productivity peaked at 23 kg N <span style="white-space:nowrap;">ha<sup>−1</sup></span> but declined with increasing N rate. The EONR combined (sites + seasons) were 37, 45, 52 and 60 <span style="white-space:nowrap;">kg·ha<sup>−1</sup></span><sup> </sup>and for the profit to cost ratio (PCR) were 2.43, 3.65, 4.86 and 5.79 at difference cost to grain price ratios (CP) = 3.6, 2.3, 1.6 and 1.2 respectively at Miesso Ethiopia. Nitrogen application had economically profitable than P. The study concluded that the application of N at 37 or 60 kg N <span style="white-space:nowrap;">ha<sup>−1</sup></span> to sorghum production could be economically profitable for those economically constrained farmers or economically not constrained farmers. Validation should be farther conducted on farmers’ fields for refining the results obtained.
文摘Models predicting optimal levels of plant defense against herbivores typically include two assumptions: 1) defense is both beneficial and costly;and 2) the relationship between costs and benefits of a defense is consistent across environments. However, the expression of costs and benefits of defense may be environmentally dependent. We examined lines of Brassica rapa, previously divergently selected for the defensive trait foliar glucosinolate content. In one set of experiments (Experiment #1), plants were grown in herbivore-free and herbivore-present environments to investigate the costs and benefits of this defense. In a second set of experiments (Experiment #2), plants were grown at two nutrient levels and two temperatures to examine the environmental context of costs of defense. In Experiment #1, increased levels of damage resulted in decreased flower production and plants from high glucosinolate lines received less damage than those from low glucosinolate lines, suggesting a benefit of this defense. In this experiment no cost of defense was detected. In Experiment #2, nutrients had a significant positive effect on flower production at 23°C, but not at 32°C. No significant effects of glucosinolate line nor interaction between nutrient environment and glucosinolate line were detected at 23°C, suggesting that no cost of defense occurred at this lower temperature. Similarly, no significant nutrient environment by glucosenolate line interaction was detected at 32°C. However, a significant effect of glucosinolate line was observed suggesting that at 32°C costs were incurred, but nutrient environment had no mitigating effect. While results from Experiment #1 suggested that defense was beneficial, but not costly, results from Experiment #2 suggested that costs of defense were temperature dependent. For species occupying broad geographic ranges, these findings of temperature-dependent costs are especially insightful with regard to the evolution of defense because differing geographic populations are likely to experience differing temperature environments.
文摘为定量化设施果类蔬菜养分投入,实现设施果蔬优质高产、绿色高效生产,本研究以山东省典型设施果类蔬菜为研究对象,基于通过农户调研与土壤样品采集测定收集的数据,结合对现有文献的综述,使用生命周期评价方法,系统分析研究区域设施果类蔬菜生产的施肥现状、土壤养分状况和环境代价及其相关关系。结果表明:山东省主栽设施果类蔬菜养分投入量高,设施番茄、黄瓜、辣椒、茄子的氮(以N计)、磷(以P2O5计)、钾(以K2O计)投入量平均达到743、600、740 kg·hm^(-2),施肥变异系数较大(CV=30.3%~43.9%),大量的肥料投入造成了较高的养分盈余,进而导致表层土壤(0~30 cm)养分含量显著升高,同时导致了较高的环境代价。设施果类蔬菜的单位面积上活性氮损失、温室气体排放、富营养化效应和酸化效应均以黄瓜生产系统最高,分别达225 kg·hm^(-2)、10058 kg CO_(2e)·hm^(-2)、124 kg PO_(4e)·hm^(-2)和63.4 kg SO_(2e)·hm^(-2),其次是茄子、番茄和辣椒。氮素盈余是导致活性氮损失的最主要因素,氮、磷、钾肥料的生产过程和施用过程是设施果类蔬菜温室气体排放、富营养化效应和酸化效应的主要贡献因子,贡献率高达80%以上。因此,为保证设施果类蔬菜产业绿色优质高质量发展,应通过优化设施蔬菜养分资源综合管理策略来减少养分盈余、降低环境代价。
