Validation of new automated turbidimetric immunoassays for the measurement of haptoglobin and inter-α-trypsin inhibitor heavy chain H4 specific for the bovine species     

Anna Bassols  José Angel Robles-Guirado  Laura Arroyo  Lourdes Soler  Natalia García  Raquel Pato  Raquel Peña  Yolanda Saco  Ramon Armengol  Fermín Lampreave  María A. Alava  Francesca Canalias  Matilde Piñeiro 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2023,52(Z1):64-74

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Using midday stem water potential for scheduling deficit irrigation in mid–late maturing peach trees under Mediterranean conditions     

José Manuel Mirás-Avalos  Francisco Pérez-Sarmiento  Rosalía Alcobendas  Juan José Alarcón  Oussama Mounzer  Emilio Nicolás 《Irrigation Science》2016,34(2):161-173

Irrigation techniques that reduce water applications are increasingly applied in areas with scarce water resources. In this study, the effect of two regulated deficit irrigation (RDI) strategies on peach [Prunus persica (L.) Batsch cv. “Catherine”] performance was studied over three growing seasons. The experimental site was located in Murcia (SE Spain), a Mediterranean region. Two RDI strategies (restricting water applications at stage II of fruit development and postharvest) based on stem water potential (Ψ_s) thresholds (?1.5 and ?1.8 MPa during fruit growth and ?1.5 and ?2.0 MPa during postharvest) were compared to a fully irrigated control. Soil water content (θ_v), Ψ_s, gas exchange parameters, vegetative growth, crop load, yield and fruit quality were determined. RDI treatments showed significantly lower values of θ_v and Ψ_s than control trees when irrigation water was restricted, causing reductions in stomatal conductance and photosynthesis rates. Vegetative growth was reduced by RDI, as lower shoot lengths and pruning weights were observed under those treatments when compared to control. However, fruit size and yield were unaffected, and fruit quality was slightly improved by RDI. Water savings from 43 to 65 % were achieved depending on the year and the RDI strategy, and no negative carryover effect was detected during the study period. In conclusion, RDI strategies using Ψ_s thresholds for scheduling irrigation in mid–late maturing peach trees under Mediterranean conditions are viable options to save water without compromising yield and even improving fruit quality.  相似文献   

垃圾填埋沼气的收集、净化与利用综述   总被引：9，自引：0，他引：9  

石磊  赵由才  唐圣钧 《中国沼气》2004,22(1):14-17

垃圾填埋沼气的回收利用是一项经济可行且对环境有益的技术.本文从填埋沼气的组成及其影响因素出发,探讨了沼气的收集、输送和贮存途径,介绍了当前的净化工艺,最后总结介绍了几种填埋沼气利用技术的特点及其适用性,并提出建立配备填埋沼气回收装置的卫生填埋场应成为我国城市垃圾处理的发展方向.  相似文献   

Monitoring forage production for farmers’ decision making     

Gonzalo Grigera  Martín OesterheldFernando Pacín 《Agricultural Systems》2007

Objective management of grazing livestock production systems needs monitoring of forage production at the managerial unit level. Our objectives were to develop a system that routinely estimates forage above-ground net primary production (ANPP) at the spatial and temporal resolution required by farmers in the Pampas of Argentina, and to facilitate adoption of the system by end users as a managerial support tool. Our approach was based on the radiation use efficiency (RUE) logic, which proposes that ANPP is determined by the amount of photosynthetically active radiation absorbed by the canopy (APAR), and the efficiency with which that energy is transformed in above-ground dry matter (radiation use efficiency, RUE). APAR is the product of incoming photosynthetically active radiation (PAR) and the fraction absorbed by the canopy (fPAR). We estimated fPAR as a non-linear function of MODIS normalized difference vegetation index (NDVI). RUE was empirically estimated for the two principal forage resources of the region, yielding the following relations: ANPP = 0.6 × APAR + 12, (R² = 0.86; p < 0.001; n = 18) for the upland sown pastures, and ANPP = 0.27 × APAR + 26, (R² = 0.74; p < 0.001; n = 18) for the lowland naturalized pastures, with ANPP in g/m²/60 days and APAR in MJ/m²/60 days. The models were able to predict independent ANPP values with acceptable accuracy. Computational procedures were automated and run in a Relational Data Base Manager System that stored and managed all the information. The system is currently monitoring 212,794 ha in 83 farms and provides monthly ANPP values for the previous month and a history of the last 6 years. The data so generated show ANPP differences between the two major forage resources, considerable variability of a given month’s ANPP among years and paddocks, and contrasting among-farm differences in the efficiency of conversion of ANPP and forage supplements into beef production. The system was well accepted by end users who utilize it mainly for making near real time decisions according to last month ANPP, and explaining results of previous production cycles by incorporating ANPP as an explicative variable. However, there were differences among farmers in the degree of utilization, apparently related to the advisor’s attitude toward this new technology. Our results indicate that (1) forage production of large extensions can be monthly monitored at the paddock level by a small laboratory with capabilities in geographic information systems, and (2) advisors and farmers apply this information to their managerial decisions.  相似文献   

Measuring versus estimating net radiation and soil heat flux: Impact on Penman–Monteith reference ET estimates in semiarid regions     

Pedro Gavilán  Joaquín Berengena  Richard G. Allen 《Agricultural Water Management》2007

The standardized ASCE Penman–Monteith and FAO-56 equations were used to estimate reference evapotranspiration (ET₀) using estimated and measured net radiation (R_n) and soil heat flux (G), based on hourly and daily meteorological data. The estimates were evaluated against lysimeter measurements. The results indicate that using measured or estimated values of R_n and G can have significant effect on the accuracy of the ET₀ estimations, especially when calculations were made on an hourly basis. The FAO-56 version performed very well during the irrigation season on a daily basis. The use of measured R_n and G did not improve ET₀ estimation on a daily basis, therefore, the use of estimated R_n and G appears to be dependable when calculations are based on 24-h weather data. When daily ET₀ was calculated from hourly estimations, the results were different depending on the version used. The ASCE version was more accurate, especially when R_n and G were measured. Therefore, measurement of R_n and G may have potential to improve estimation only when daily ET₀ is calculated from hourly estimations. The PM FAO-56 version was always a little less accurate than the ASCE version. For hourly calculations, using a constant surface resistance (as in FAO-56 version), the PM method underpredicted for high evaporative demand and vice versa. The ASCE version performed better than PM FAO-56 version when R_n and G were measured and estimated. Therefore, ASCE version tended to provide quite accurate values of hourly ET₀, even using estimated values of R_n and G. As conclusion, the methods proposed by FAO-56 for estimating R_n and G tended to produce accurate estimates for daily and hourly ET₀ under semiarid conditions and can be used with some degree of confidence for estimating ET₀. In addition, results suggest that the ASCE standardized equation on an hourly basis improved the accuracy of ET₀ estimation with respect to the FAO-56 version.  相似文献   

SIRIAS: a simulation model for sprinkler irrigation     

P. Carrión  J. Tarjuelo  J. Montero 《Irrigation Science》2001,20(2):73-84

Uniformity of distribution in irrigation systems plays an important role in the optimum use of irrigation water, with direct repercussions on water-use efficiency and production. To evaluate the effects of the wind on sprinkler water uniformity, it is necessary to measure infield water distribution under different wind conditions and then calculate the parameters that define water distribution. This paper perfects the SIRIAS simulation model for sprinkler systems, which can be used to design new irrigation installations or to improve existing ones. Using ballistic theory to simulate the trajectory of drops discharged by the sprinkler, the model obtains wind-distorted water distribution, with a new formulation for the air drag coefficient. It takes into account three options to distribute the evaporation and drift losses in the irrigation process. SIRIAS software has been programmed using Delphi language for Windows 95, 98 and NT.  相似文献   

Multivariate analysis of invasive plant species distributions in southern US forests     

Lázaro-Lobo  Adrián  Ramirez-Reyes  Carlos  Lucardi  Rima D.  Ervin  Gary N. 《Landscape Ecology》2021,36(12):3539-3555

Landscape Ecology - Invasive plants cause significant impacts in forested areas throughout the world. However, little is known about the relative importance of environmental drivers on the...  相似文献   

Sediment production from unpaved roads in a sub-tropical dry setting — Southwestern Puerto Rico   总被引：1，自引：0，他引：1  

Carlos E. Ramos Scharrón 《CATENA》2010

The threat imposed by increased sediment loading rates ranks among the most important stressors affecting coral reef ecosystems worldwide. This study represents an effort to quantify the effects of unpaved roads on erosion rates in a dry sub-tropical area of Puerto Rico and is intended to aid in developing scientifically-based erosion mitigation strategies. Hence, the specific objectives of this study were to: (1) measure sediment production rates from unpaved roads; (2) evaluate the effect of precipitation, rainfall erosivity, slope, plot length, and vegetation cover on sediment production rates; and (3) compare measured sediment production rates to published surface erosion data from roaded and natural sites in the Eastern Caribbean. Sediment production from nine abandoned road segments with varying slopes and plot lengths were measured with sediment traps in southwestern Puerto Rico from August 2003 to September 2005.  相似文献   

Flavor and quality characteristics of salted and desalted cod (Gadus morhua) produced by different salting methods     

Jónsdóttir R  Sveinsdóttir K  Magnússon H  Arason S  Lauritzsen K  Thorarinsdottir KA 《Journal of agricultural and food chemistry》2011,59(8):3893-3904

Flavor characterization and quality of salt-cured and desalted cod (Gadus morhua) products was studied using sensory analysis and gas chromatography techniques. The products were produced in Iceland using two different processing methods (filleting and splitting) and three different salting procedures, i.e., the old single-step kench salting or a multistep procedure, and presalting (injection and brine salting or only brine salting), which was followed by kench salting. The main difference observed was between fillets and split fish, where the split fish was darker and had stronger flavor characteristics. Comparison of different salting procedures showed that the use of presalting improved the appearance of the salted products, which can be described as increased lightness and reduced yellowness of the products. In the same products, the intensity of curing flavors was milder, as described by sensory analysis and key aroma compounds. Derivatives from lipid and protein degradation contribute to the characteristic flavor of the salted products.  相似文献   

Atmospheric Mercury Fluxes in a Southern Boreal Forest and Wetland     

Katriina Kyllönen  Hannele Hakola  Heidi Hellén  Markku Korhonen  Matti Verta 《Water, air, and soil pollution》2012,223(3):1171-1182

Total gaseous mercury (TGM) fluxes from the forest floor and a boreal wetland were measured by a flux chamber technique coupled with an automatic mercury vapour analyser. The fluxes were measured at three sampling sites in southern Finland, 61°14′ N, 25°04′ E in summer 2007, with additionally in situ TGM concentrations in the air at one of the sites and mercury bulk deposition at another. Most of the flux data were collected during the daytime. At one of the sites, diurnal flux behaviour was studied, and a clear cycle with an afternoon maximum and a night minimum was observed. The highest emissions (up to 3.5 ng m⁻² h⁻¹) were observed at the forest floor site having a moss and grass cover. At the wetland and litter-rich forest floor sites, the emissions were below 1 ng m⁻² h⁻¹ and sometimes negative (down to −1.0 ng m⁻² h⁻¹), indicating mercury uptake. The measured average fluxes in August were 0.9 ± 1.1 and 0.2 ± 0.3 ng m⁻² h⁻¹ for the forest floor sites and wetland sites, respectively. The flux data were compared with the mercury bulk deposition, which proved to be of the same magnitude, but opposite in sign. At the mossy forest floor site, the extrapolated TGM emissions were 130% of the Hg deposition in August 2007. Comparison with other studies showed that the fluxes in background areas are relatively uniform, regardless of measurement site location and method used. Airborne TGM remained at the background level during the study, with an average value of 1.3 ± 0.2 ng m⁻³; it frequently showed a diurnal cycle pattern.  相似文献