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1.
Transformation of the nitrogen cycle: recent trends, questions, and potential solutions 总被引：12，自引：0，他引：12
Galloway JN Townsend AR Erisman JW Bekunda M Cai Z Freney JR Martinelli LA Seitzinger SP Sutton MA 《Science (New York, N.Y.)》2008,320(5878):889-892
Humans continue to transform the global nitrogen cycle at a record pace, reflecting an increased combustion of fossil fuels, growing demand for nitrogen in agriculture and industry, and pervasive inefficiencies in its use. Much anthropogenic nitrogen is lost to air, water, and land to cause a cascade of environmental and human health problems. Simultaneously, food production in some parts of the world is nitrogen-deficient, highlighting inequities in the distribution of nitrogen-containing fertilizers. Optimizing the need for a key human resource while minimizing its negative consequences requires an integrated interdisciplinary approach and the development of strategies to decrease nitrogen-containing waste. 相似文献
2.
Puglia GD Freeman LM Rush JE King RG Crawford SL 《American journal of veterinary research》2006,67(9):1533-1540
OBJECTIVE: To develop and assess the reproducibility of a protocol to noninvasively test endothelial function in dogs on the basis of the flow-mediated vasodilation (FMD) procedure used in humans. ANIMALS: 5 healthy spayed female dogs. PROCEDURES: Luminal arterial diameter and blood flow velocity in the brachial and femoral arteries were measured with ultrasonography. The within-dog reproducibility of these ultrasonographic measurements was tested. An occlusion period of 1, 3, or 5 minutes with an inflatable cuff was used to create the FMD response. Measurements made at 15, 30, and 60 seconds following release of the occlusion were compared with measurements made immediately prior to each occlusion to assess the FMD response. RESULTS: Within-dog reproducibility of measurements revealed moderate to high correlations. Change from baseline in luminal arterial diameter was most substantial when measured at 30 seconds following release of occlusion, whereas blood flow velocity changes were maximal when measured at 15 seconds following release. The brachial imaging site provided a larger number of significant FMD responses than the femoral site. The 3-minute occlusion period provided equal or better responses than the 5-minute occlusion period. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic measurement of the FMD responses was a feasible and reproducible technique and significant changes from baseline were detected. The FMD responses in dogs were most substantial when performed at the brachial artery with blood flow velocity and luminal arterial diameter changes from baseline measured at 15 and 30 seconds, respectively, following release of a 3-minute occlusion period. 相似文献
3.
OBJECTIVES: To conduct a needs assessment of all aspects of food provision in a residential home and to evaluate a subsequent nutrition intervention. DESIGN: An intervention study using a before and after design. A participatory approach was adopted and quantitative and qualitative methods used throughout. The intervention involved a revised menu, kitchen equipment, and establishing wholesale shopping and food donations. SETTING: A residential home for senior citizens in Guyana. RESULTS: Meals at the home were nutritionally inadequate and deeply unpopular with the residents. Intakes of fruits and vegetables were low and the home was heavily reliant on donated soya mince and rice. Meals were served within an eight-hour period to accommodate the staff's hours of work. Cutbacks in the food budget indicated that the financial state of the home explained some of the problems. The intervention was unable to address all problems identified, but led to substantial improvements in the nutritional adequacy of the food provided following the inclusion in the menu of a number of nutrient-dense foods such as chicken liver. The new menu was acceptable to the cooks and largely popular with the residents, although some problems persisted. CONCLUSIONS: The results show that improvements in the nutrient profile of the diet could be achieved with a flexible, community-based, participatory approach that addressed all elements of a home's food provision system. The changes also proved largely popular with the residents, thus potentially contributing to their quality of life. 相似文献
4.
Sybil Sharvelle Rebecca Lattyak M. Katherine Banks 《Water, air, and soil pollution》2007,183(1-4):177-186
The biodegradation kinetics of anionic (sodium laureth sulfate – SLES), amphoteric (disodium cocoamphodiacetate – DSCADA), and nonionic surfactants (polyalcohol ethoxylate – PAE) were assessed in this laboratory study. Similar degradation behavior was observed for all surfactants with only a fraction of the parent compound readily biodegradable. Biodegradation, as estimated by COD removal, was initially (i.e., within 24 h) rapid, however only 40–70% of the surfactant molecules were readily biodegradable. Intrinsic kinetic parameters were successfully quantified for the readily biodegradable component of the surfactant. Inhibition was not observed and microbial kinetics of SLES, DSCADA, and PAE degradation fit the Monod model well. Average μ-S curves were generated for each surfactant. Based on these results, complete degradation of the target surfactants using biological waste treatment would be limited. 相似文献
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6.
Masoud Negahban-Azar Sybil E. Sharvelle Mary E. Stromberger Christopher Olson Larry A. Roesner 《Water, air, and soil pollution》2012,223(8):4733-4749
While interest in and adoption of graywater reuse for irrigation has rapidly grown in recent years, little is known about the long-term effects of graywater irrigation. Concerns exist in relation to the presence of pathogenic organisms, fate of personal care products, and accumulation of salts. The purpose of this research was to evaluate the long-term effects of graywater irrigation to soil quality under real conditions where homeowners may not always apply graywater in a highly controlled manner. Four households from different climatic and geological conditions were selected for sampling (AZ, CA, CO, and TX) where graywater was applied for irrigation for a minimum of 5?years. Soil samples were collected in areas irrigated with graywater and areas irrigated with freshwater within the same yard. Soil cores were taken at depths of 0?C15, 15?C30, and 30?C100?cm and analyzed separately for surfactants, antimicrobials, sodium adsorption ratio (SAR), electrical conductivity (EC), extractable boron, fecal indicator organisms (E. coli, enterococci, and Clostridium perfringens), and soil dehydrogenase activity. In surface soil samples (0?C15?cm), the average total surfactant concentration (over all sites) was higher in graywater-irrigated soil (0.078?±?0.033) compared to freshwater-irrigated soil (0.030?±?0.025?mg?kg?1). This difference was not found to be significant (P?>?0.05). Triclosan and triclocarban were detected in surface soil samples at some locations (3.8?C6.3 and 3.5?C9.1???g?kg?1, respectively), but not in samples deeper than 15?cm. Among the sampling locations, the TX household appeared to be most impacted by graywater, as evidenced by elevated SAR, potentially toxic levels of B, and relatively high numbers of E. coli and enterococci due to 30?years of graywater application for irrigation. 相似文献
7.
Megan F. Whelan DVM DACVECC ; Therese E. O'Toole DVM DACVIM ; Daniel L. Chan DVM DACVECC DACVN MRCVS ; Elizabeth A. Rozanski DVM DACVECC DACVIM ; Armelle M. deLaforcade DVM DACVECC ; Sybil L. Crawford PhD Susan M. Cotter DVM DACVIM 《Journal of Veterinary Emergency and Critical Care》2009,19(2):158-164
Objective – To determine the utility of human intravenous immunoglobulin (hIVIG) for the initial treatment of canine immune-mediated hemolytic anemia (IMHA).
Design – Blinded, randomized, clinical trial.
Setting – Veterinary teaching hospital.
Animals – Twenty-eight, client-owned dogs with primary IMHA.
Interventions – At enrollment, after diagnosis of IMHA, dogs were randomly assigned to receive either hIVIG or placebo, in a blinded fashion. For the next 14 days, all dogs received glucocorticoids as the sole immunosuppressant agent. All dogs received low-molecular-weight heparin as an anticoagulant. D-dimer concentrations were evaluated at the beginning and end of the study protocol to monitor for thromboembolic complications.
Measurements and Main Results – Twenty-five of 28 dogs (89%) were discharged from the hospital. Thirteen of those received hIVIG and 12 received placebo. Twenty-four dogs (86%) were alive 14 days after enrollment, and of these 13 received hIVIG and 11 received placebo. D-dimer concentrations were elevated in 86% of all dogs at the time of diagnosis.
Conclusions – For initial treatment of dogs with IMHA, the addition of hIVIG to corticosteroid treatment did not improve initial response, nor did it shorten hospitalization. 相似文献
Design – Blinded, randomized, clinical trial.
Setting – Veterinary teaching hospital.
Animals – Twenty-eight, client-owned dogs with primary IMHA.
Interventions – At enrollment, after diagnosis of IMHA, dogs were randomly assigned to receive either hIVIG or placebo, in a blinded fashion. For the next 14 days, all dogs received glucocorticoids as the sole immunosuppressant agent. All dogs received low-molecular-weight heparin as an anticoagulant. D-dimer concentrations were evaluated at the beginning and end of the study protocol to monitor for thromboembolic complications.
Measurements and Main Results – Twenty-five of 28 dogs (89%) were discharged from the hospital. Thirteen of those received hIVIG and 12 received placebo. Twenty-four dogs (86%) were alive 14 days after enrollment, and of these 13 received hIVIG and 11 received placebo. D-dimer concentrations were elevated in 86% of all dogs at the time of diagnosis.
Conclusions – For initial treatment of dogs with IMHA, the addition of hIVIG to corticosteroid treatment did not improve initial response, nor did it shorten hospitalization. 相似文献
8.
R. P. Singh J. Huerta-Espino S. Bhavani S. A. Herrera-Foessel D. Singh P. K. Singh G. Velu R. E. Mason Y. Jin P. Njau J. Crossa 《Euphytica》2011,179(1):175-186
Rust diseases continue to cause significant losses to wheat production worldwide. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach is to deploy varieties that posses adult plant resistance (APR) based on combinations of minor, slow rusting genes. When present alone, APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4?C5 such genes usually result in ??near-immunity?? or a high level of resistance. Although high diversity for APR occurs for all three rusts in improved germplasm, relatively few genes are characterized in detail. Breeding for APR to leaf rust and stripe rust in CIMMYT spring wheats was initiated in the early 1970s by crossing slow rusting parents that lacked effective race-specific resistance genes to prevalent pathogen populations and selecting plants in segregating populations under high disease pressure in field nurseries. Consequently most of the wheat germplasm distributed worldwide now possesses near-immunity or adequate levels of resistance. Some semidwarf wheats such as Kingbird, Pavon 76, Kiritati and Parula show high levels of APR to stem rust race Ug99 and its derivatives based on the Sr2-complex, or a combination of Sr2 with other uncharacterized slow rusting genes. These parents are being utilized in our crossing program and a Mexico-Kenya shuttle breeding scheme is used for selecting resistance to Ug99. High frequencies of lines with near-immunity to moderate levels of resistance are now emerging from these activities. After further yield trials and quality assessments these lines will be distributed internationally through the CIMMYT nursery system. 相似文献
9.
Progress Towards Genetics and Breeding for Minor Genes Based Resistance to Ug99 and Other Rusts in CIMMYT High-Yielding Spring Wheat 
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下载免费PDF全文 Ravi Prakash Singh Sybil Herrera-Foessel Julio Huerta-Espino Sukhwinder Singh Sridhar Bhavani Caixia Lan Bhoja Raj Basnet 《农业科学学报》2014,13(2):255-261
Wheat rusts continue to cause significant losses worldwide despite major efforts given to their genetic control. This is due to frequent evolution and selection of virulence in pathogen overcoming the deployed race-specific resistance genes. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach being implemented at CIMMYT is to deploy varieties that posses adult plant resistance （APR） based on combinations of minor, slow rusting genes. When present alone, the APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4 or 5 minor genes usually result in ＂near-immunity＂ or a high level of resistance. Although only a few APR genes are catalogued, various APR QTLs are now known and could lead to further characterization of additional genes. Four characterized genes have pleiotropic effects in conferring partial APR to all 3 rusts and powdery mildew, thus simplifying the task of breeding wheat varieties that are resistant to multiple diseases. Significant progress was made recently in developing high-yielding wheat germplasm that possesses high levels of APR to all three rusts by implementing a Mexico- Kenya shuttle breeding scheme. Parents with APR to Ug99 were hybridized with high-yielding parents that had adequate to high levels of APR to leaf rust and yellow rust. Segregating populations and advanced lines from these crosses were selected under high rust pressures in Mexico （leaf rust and yellow rust） and Kenya （Ug99 stem rust and yellow rust） to identify high- yielding progenies that possess high to adequate APR to all three rusts. International distribution of these high-yielding wheats is underway through CIMMYT intemational yield trials and screening nurseries. It is expected that several wheat varieties with APR to three rusts will be released and grown in various countries in the near-future that will allow determining the durability of resistance. 相似文献
10.
S. A. Herrera-Foessel R. P. Singh J. Huerta-Espino J. Crossa A. Djurle J. Yuen 《Euphytica》2007,155(3):361-369
Information about slow rusting resistance to leaf rust (Puccinia triticina) in durum wheat (Triticum turgidum var. durum) is limited. Three slow rusting components, latent period, receptivity, and uredinium size, were determined at the adult
plant stage for seven durums with slow rusting resistance to leaf rust and two susceptible durums in three greenhouse experiments.
Additionally, area under the disease progress curve (AUDPC) and final disease severity (FDS) were determined in three field
trials under artificial epidemics with the same P. triticina race BBG/BN. Compared to the most susceptible check, the AUDPC and FDS of slow rusting resistant durums were significantly
lower and ranged from 13–47 to 22–59%, respectively. The latent period was significantly longer (8.5–10.3 days) and uredinium
size significantly smaller (8.1–14.8 × 10−2 mm2) on slow rusting durums than on the susceptible checks (8.0 days and 17.3–23.8 × 10−2 mm2, respectively). Uredinium size was the most stable slow rusting component across experiments. Correlations between uredinium
size versus AUDPC and uredinium size versus FDS for each environment were high (r = 0.86–0.88). Correlations between latent period and field parameters were significant (r = −0.60 to −0.80). Correlations between receptivity and the field parameters were not significant. A multiple regression
analysis showed that the variation in AUDPC and FDS was significantly explained only by uredinium size (P < 0.0001). The best slow rusting resistant lines can be used for developing high-yielding durums with more durable resistance
to leaf rust. 相似文献