Extended Burr XII Regression Models: Theory and Applications

We introduce two new lifetime distributions by compounding the Burr XII (BXII) and geometric distributions. We derive their moments and moment-generating and quantile functions. We also define two new extended regression models based on the logarithms of these distributions. The regression models are very useful in the analysis of real data since they can provide better fits than other special regression models. We formulate a new cure rate survival model, where the number of competing causes of the event of interest follows a geometric distribution and the time to this event has the BXII geometric distribution. The estimation of the model parameters is performed by maximum likelihood. We illustrate the importance of the new models by means of two real datasets. The first dataset comes from a study carried out at the Department of Entomology of the Luiz de Queiroz School of Agriculture, University of São Paulo, which aims to assess the longevity of the Mediterranean fruit fly (ceratitis capitata). The second dataset comes from the area of biology.     

Genomics as a Tool for Cereal Chemistry

Genomics is providing a new set of tools for cereal chemistry. Analysis of the DNA of the major cereals is increasing the understanding of the basis of grain quality at the gene level. Differences in the sequence of the gene in different cultivars or differences in the level of expression of the gene may be used to explain differences in processing or end-use quality characteristics. For example, quantitative analysis of the levels of expression of genes at different stages during seed development in wheat or germination in barley can be used to define the genetic basis of differences in wheat and barley quality. Rice quality traits such as fragrance and gelatinization temperature (cooking temperature) can be explained by DNA sequence differences in specific genes identified using genomics approaches. Rapid and reliable species and cultivar identification based on DNA analysis methods developed using genomics tools can be applied to grain and to food products. This technology has special advantages in the analysis of complex mixtures of cereals. Technologies for very high-throughput and very low-cost analysis of large numbers of samples are now available. These may be applied by cereal chemists at many levels: selection in cereal breeding, optimizing processing, and analysis of the identity and composition of grain or food samples.     

Using Thermogravimetry as a Simple Tool for Nutrient Assessment in Fire Affected Soils

Nutrient availability can be a limiting factor in the recovery of ecosystems after wildfire. Its evaluation is therefore critical for selecting appropriate restoration strategies in the post‐fire period. This study explores, for the first time, the use of thermogravimetry (TG) as a rapid proxy for nutrient availability and soil recovery. Soil samples from five burned and unburned sites in Andisols of Tenerife (Spain) were selected to examine the medium‐term impact of fire. Key soil chemical parameters [pH, electric conductivity, cation exchange capacity (CEC), main cation and anions in the soil solution, total organic carbon (TOC), total nitrogen (TN) and available phosphorus] were determined and thermogravimetry performed. Burned soils showed significantly higher pH, Ca²⁺ and Mg²⁺ and a lower CEC, TOC and TN than the unburned counterparts, and a site‐dependent response for soluble SO₄²⁻ and available phosphorus was observed in the medium term. Time elapsed since fire could have masked additional fire impacts. Thermogravimetry data allowed reasonable prediction of most soil properties and parameters, with r ² ranging from 0·4 to 0·9. The results demonstrate that soluble nutrient content is directly related to the amount of ash in the soil. The decrease of labile carboxyl‐C was associated with an increase of pH and decrease of CEC, whereas the increase of recalcitrant and refractory pools was associated with the amount of TOC and TN. The results suggest that this novel application of an established method can provide, following an initial calibration step, rapid and inexpensive proxies for key parameters necessary for assessing fire‐induced ecosystem degradation and designing suitable restoration strategies in the post‐fire period. Copyright © 2017 John Wiley & Sons, Ltd.     

Reducing NO2 Pollution over Urban Areas: Air Quality Modelling as a Fundamental Management Tool

Recently, specific air quality problems have been detected in the northern region of Portugal. The nitrogen oxide (NO₂) annual limit value has been surpassed at several air quality monitoring stations in the northern region, and according to European legislation, air quality plans must be designed and implemented to reduce those levels. The analysis of the air quality data from the stations concerning NO₂ exceedances indicates that traffic is responsible for an increase of more than 40?% compared with the urban background value. Specific measures to reduce NOx emissions have been selected and are related not only mainly to the traffic sector but also to the industrial and residential combustion sectors. The main objective of this study is to investigate the impact of the selected measures on the ambient levels of NO₂ in northern Portugal using a numerical modelling tool??The Air Pollution Model (TAPM). TAPM was applied over the study region using a 120?×?120-km² simulation domain and a spatial resolution of 4.8?×?4.8?km². The entire year of 2010 was simulated and was set as the base year to analyse the impact of the selected measures. Two scenarios have been defined and simulated: the base situation, which considers current NOx emissions, and the reduction scenario for which NOx emissions were re-estimated considering the implementation of the measures. The modelling results demonstrate a decrease of 4?C5???g?m^?3 in the annual NO₂ levels in the study region. Moreover, the implementation of the selected measures will allow compliance with the NO₂ annual limit values in three of the five air quality stations that measured levels surpassing those established by legislation. This situation demands additional measures that should be implemented at the local level and that particularly focus on the traffic sector.     

Capillary Electrophoresis as a Tool for Evaluating Lactic Acid Production from Sorghum

Sorghum is an underutilized resource for the production of bioindustrial chemicals like lactic acid. Capillary electrophoresis (CE) was tested to monitor the fermentation process, i.e., quantify the amount of lactic acid and by‐products in the fermentation broth using phosphate buffer pH 6.25 containing the electroosmotic flow modifier cetyltrimethylammonium bromide (CTAB). High levels of calcium carbonate were required during fermentation to stabilize the pH and these caused considerably prolonged migration times in CE. A 1:10 dilution of the samples with water was the best way to reduce salt load and thus conductivity in the sample plug, and thus to eliminate the problem of prolonged migration times. Further improvements were achieved by rinsing the capillary with HCl and water after each run, rather than NaOH and water. HCl might more efficiently remove Ca²⁺ ions from the capillary surface. The fermentation broth studied was based on liquefied sorghum inoculated with Rhizopus oryzae. The main product was lactic acid (24.60 ± 0.56 g/L) and a significant by‐product was fumaric acid (1.07 ± 0.04 g/L).     

Soil Testing as a Tool for On-Farm Fertility Management: Experience from the Semi-arid Zone of India

Rainfed agriculture in the dry regions is affected by water shortages. Our earlier research showed that the deficiencies not only of major nutrients but also those of sulfur (S) and micronutrients are holding back the potential of agricultural production systems. The objectives of this article are to discuss the efficacy of soil testing to diagnose nutrient deficiencies using 28,270 diverse soil samples collected from farmers' fields in the semi-arid tropical (SAT) regions of India and to confirm the efficacy of the soil test-based balanced nutrient management in enhancing productivity of a range of crops in on-farm farmer participatory trials under rainfed conditions. Results of a large numbers of on-farm trials demonstrated that soil testing is indeed an effective tool for on-farm fertility management, a prerequisite for sustainably enhancing the productivity in rainfed areas in the SAT regions of India. The need to strengthen the soil-testing infrastructure in the country is emphasized.     

Development and Assessment of Neural Network and Multiple Regression Models in Order to Predict PM10 Levels in a Medium-sized Mediterranean City

Suspended particulate matter is significantly related to the degradation of air quality in urban agglomerations, generating adverse health effects. Therefore, the ability to make accurate predictions of particulate ambient concentrations is important in order to improve public awareness and air quality management. This study aims at developing models using multiple regression and neural network (NN) methods that might produce accurate 24-h predictions of daily average (DA) value of PM10 concentration and at comparatively assessing the above mentioned techniques. Pollution and meteorological data were collected in the urban area of Volos, a medium-sized coastal city in central Greece, whose population and industrialization is continuously increasing. Both models utilize five variables as inputs, which incorporate meteorology (difference between daily maximum and minimum hourly value of ground temperature and DA value of wind speed), persistency in PM10 levels and weekly and annual variation of PM10 concentration. The validation of the models revealed that NN model showed slightly better skills in forecasting PM10 concentrations, as the regression and the NN model can forecast 55 and 61% of the variance of the data, respectively. In addition, several statistical indexes were calculated in order to verify the quality and reliability of the developed models. The results showed that their skill scores are satisfying, presenting minor differences. It was also found that both are capable of predicting the exceedances of the limit value of 50 μg/m³ at a satisfactory level.     

TENAX萃取表征土壤中多溴联苯醚（PBDEs）生物可利用性研究

为了建立一种用Tenax萃取快速评价土壤中多溴联苯醚生物可利用性的方法,本研究以商业多溴联苯醚DE-71和DE-79中6种主要同系物（BDE-47,99,100,154,153,183）为研究对象,对不同染毒浓度的土壤用Tenax萃取6 h,并将Tenax萃取结果与土壤-蚯蚓（赤子爱胜蚓Eisenia foetida）生物富集试验结果进行了比较。结果表明,单位质量土壤中被Tenax萃取出的PBDEs的质量随土壤中PBDEs浓度的增大而增加,随各同系物lgKow值的增大而降低。6 h Tenax萃取的富集因子TSAF6与蚯蚓的生物富集因子BSAF之间具有良好的相关性,表明6 h Tenax萃取能够有效表征土壤中PBDEs的生物可利用性。     

One-Step Extraction Procedure as an Easy Tool for Monitoring a Full-Scale Composting Plant

ABSTRACT. Composting is an efficient technique for managing the increasing production of organic wastes since it transforms them into a valuable product that can be applied to soil to improve it. However, it is necessary to ensure the adequate properties of this product for a proper agricultural or environmental application. Various parameters have been proposed as estimators of the evolution of the composting process, nevertheless there is a lack of easy techniques with a wide application range for monitoring it. This study evaluated some parameters that can be used to test compost evolution in samples of composted sewage sludge under full-scale conditions. Total extractable carbon (TEC) by alkaline solution of sodium pyrophosphate, humic acids (HA), fulvic acids (FA), and the ratio of them (HA/FA) were obtained by a one-step extraction procedure. Results were compared with those obtained after an official extraction method for the same parameters. Total organic matter was calculated by calcination (TOM%). The objective was to assess the usefulness of the one-step extraction as an easy and cheap tool for monitoring the composting process. The results indicate that both extraction procedures show a statistically significant correlation between them and with TOM%. Therefore, TEC obtained by the one-step extraction procedure can provide useful information about the evolution of the composting process of compost samples with the easiest methodology.     

Siderophore-Producing Rhizobacteria as a Promising Tool for Empowering Plants to Cope with Iron Limitation in Saline Soils: A Review

Iron (Fe) bioavailability to plants is reduced in saline soils; however, the exact mechanisms underlying this effect are not yet completely understood. Siderophore-expressing rhizobacteria may represent a promising alternative to chemical fertilizers by simultaneously tackling salt-stress effects and Fe limitation in saline soils. In addition to draught, plants growing in arid soils face two other major challenges:high salinity and Fe deficiency. Salinity attenuates growth, affects plant physiology, and causes nutrient imbalance, which is, in fact, one of the major consequences of saline stress. Iron is a micronutrient essential for plant development, and it is required by several metalloenzymes involved in photosynthesis and respiration. Iron deficiency is associated with chlorosis and low crop productivity. The role of microbial siderophores in Fe supply to plants and the effect of plant growth-promoting rhizobacteria (PGPR) on the mitigation of saline stress in crop culture are well documented. However, the dual effect of siderophore-producing PGPR, both on salt stress and Fe limitation, is still poorly explored. This review provides a critical overview of the combined effects of Fe limitation and soil salinization as challenges to modern agriculture and intends to summarize some indirect evidence that argues in favour of siderophore-producing PGPR as biofertilization agents in salinized soils. Recent developments and future perspectives on the use of PGPR are discussed as clues to sustainable agricultural practices in the context of present and future climate change scenarios.     

Using Synchronous Fluorescence Technique as a Water Quality Monitoring Tool for an Urban River

This paper presents a study performed to evaluate the feasibility of implementing a series of heating rods within a zero-valent iron permeable reactive barrier (ZVI-PRB) to enhance the conventional design of PRBs, and thus to improve the barrier’s removal efficiency, and reduce construction and reactive material costs. A numerical modeling approach is undertaken where a hypothetical case is introduced and typical site values are assigned to it. The amount of electrical energy required to heat the barrier from an initial temperature, T ₁, to a final temperature, T ₂ is assessed. Through different simulation cases, the effect of (1) initial temperature of the groundwater entering the PRB, (2) different amounts of total heat injected, (3) distribution of the heating rods, and (4) different types of porous media, on the temperature increase within the PRB are evaluated. Results show that the amount of energy required to increase the temperature of our hypothetical case by 10°C is approximately 935 W, which could be provided by renewable energies such as solar. It is explained that there are multiple benefits for increasing the temperature within the PRB. Apart from boosting reaction rates, temperature increase can reduce water viscosity and increase flow within the barrier, which broadens a barrier’s catch area. It can enhance solubility of gases to reduce blockage caused by gas generation. An upward flow is formed inside the wall which can also help reduce gas blockage. By implementing heating rods, design widths are reduced, which could potentially reduce the materials (thus cost) used and/or justify the use of more expensive reactive material in PRBs. Heating the PRB was found to generate a heat plume of 20 m length downstream of the PRB after one year, which would increase biodegradation of the residual contaminants leaving the PRB within this zone. Overall, it is concluded that implementing the proposed technology within a ZVI-PRB can be justified, and is found to be beneficial in many aspects.     

作物生长模型的应用研究进展

作物生长模型不仅能够进行单点尺度上作物生长发育的动态模拟,而且能够从系统角度评价作物生长状态与环境要素的关系。本文通过梳理当前作物生长模型应用的诸多研究成果,剖析模型在气候变化对农业生产影响研究、作物生长模型区域应用中的关键问题,总结了当前以作物生长模型为核心的农业决策支持系统开发的研究情况,意在促进作物生长模型在生态、农业、区域气候资源和气候变化等研究中更广泛地应用。结果表明,作物生长模型在国内外的研究与应用广泛而深入,在气候变化背景下,应用作物生长模型进行历史时期气候条件和农业气象灾害对作物生产状况和产量的影响研究已相当广泛且相对成熟。利用全球气候模式（GCM）或区域气候模式（RCM）构建未来气候变化情景,再与作物生长模型耦合已发展成为评估未来气候变化对农业生产影响的重要手段。通过集成与整合多作物生长模型、多气候模式集合模拟、优化气候模拟数据订正方法可有效降低气候变化对农业生产影响评估的不确定性。遥感数据同化技术能够将站点模型运用到区域尺度上评价不同环境因子对农业生产的影响,拓宽了作物生长模型的应用尺度范围并有效提高作物产量估算的精度。以作物生长模型为核心的农业决策支持系统的研究与应用越来越多元化,是辅助农业生产管理和决策的重要工具。然而,由于作物生态系统的复杂性,作物生长模型模拟结果仍存在很大的不确定性,今后对作物生长机理及过程间耦合机制的探索还需加强,以便进一步完善和改进模型,促进作物生长模型更广泛地应用。     

基于评估模型的陕西省水资源气候影响分析

利用陕西省1961—2009年96个观测站的年降水、气温资料以及1997—2006年水利部公布的水资源资料,基于线性拟合、水资源丰枯评价指标、变差系数及产水模数等方法和指标,对陕西省近50 a来的水资源状况进行了气候影响分析。结果表明,基于降水、气温的水资源评估模型能够对陕西省水资源状况进行评估,且评估效果好于只考虑降水的评估模型。近50 a来陕西省气候趋于暖干,年平均气温自20世纪90年代升高,1996年前后发生突变;年降水自20世纪80年代中后期减少,1988年前后发生突变。受气温升高,降水减少影响,近50 a来陕西省水资源量呈减少趋势,1991年前后发生突变,水资源量显著减少。20世纪90年代之前,陕西省水资源量正常偏多,之后水资源正常偏枯,且年际变化显著,年水资源量不稳定。陕西省属于旱年缺水类型,天然供水量的减少增加了水资源利用率,水资源供需压力增大。     

Critical Soil Zinc Deficiency Concentration and Tissue Iron: Zinc Ratio as a Diagnostic Tool for Prediction of Zinc Deficiency in Corn

ABSTRACT

Zinc (Zn) fertilizer application is most economic if based on soil test and plant analysis information. The aim of this study was to determine the soil test [diethylenetrinitrilopentaacetate (DTPA) and ethylenetriaminepentaacetic acid (EDTA) extractable] Zn-critical levels and tissue Fe/Zn ratio for corn (Zea mays L.). A greenhouse experiment with 12 soil series and two Zn fertilizer treatments (0 and 15 mg Zn kg^?1 as zinc sulfate) was conducted. Critical Zn deficiency levels were determined using the Cate-Nelson procedure. Relative corn yield varied from 0.59 to 1.64. Critical deficiency levels based on the Cate-Nelson method were 1.50 and 1.17 mg kg^?1 for DTPA and EDTA-extracted soil Zn, respectively. No accurate critical deficiency level could be established using the shoot Zn concentrations. The critical iron (Fe)/Zn ratio in the corn shoot was 3.9. Values greater than 3.9 indicate hidden Zn deficiency and probable response to applied Zn.     

The CGIAR Virtual Library: A Vital Tool to Enhance Access to Agricultural Research

Literature searching instruments are available via the Internet, but one has to conduct several individual searches to retrieve relevant scholarly materials for research. This scenario led information experts from the Consultative Group on International Agricultural Research (CGIAR) to find ways to make life easier for scientists. The collaboration among Information and IT managers resulted in the launch of the CGIAR Virtual Library (CGVLibrary) in 2006. CGIAR supports 15 diverse international centers, located worldwide, which generate scholarly research results that are considered as public goods and must be shared freely with the international community. The CGVLibrary enables federated searching of catalogs and databases and carries hyperlinks to full-text CGIAR documents. This article provides an analysis of the content of the CGVLibrary, of the various information avenues it opens for improving access to agricultural research, and of how the tool is being improved and marketed to promote awareness and worldwide use.     

Modeling Urban PM<Subscript>2.5</Subscript> Concentration by Combining Regression Models and Spectral Unmixing Analysis in a Region of East China

Understanding the spatial distribution of PM_2.5 concentration and its contributing environmental variables is critical to develop strategies of addressing adverse effects of the particulate pollution. In this study, a range of meteorological and land use factors were incorporated into a linear regression (LR) model and a logistic model-based regression (LMR) model to simulate the annual and winter PM_2.5 concentrations. The vegetation cover, derived from a linear spectral unmixing analysis (LSUA), and the normalized difference built-up index (NDBI), were found to improve the goodness of fit of the models. The study shows that (1) both the LR and the LMR agree on the predicted spatial patterns of PM_2.5 concentration and (2) the goodness of fit is higher for the models established based on the annual PM_2.5 concentration than that based on the winter PM_2.5. The modeling results show that higher PM_2.5 concentration coincided with the major urban area for the annual average but focused on the suburban and rural areas for the winter. The methods introduced in this study can potentially be applied to similar regions in other developing countries.     

Microbial Transglutaminase as a Tool to Restore the Functionality of Gluten from Insect‐Damaged Wheat

In some wheat‐growing countries, considerable quantities of commercial wheat are rendered unusable in standard baking because of preharvest damage of the grain by protease‐injecting bugs. In the present study, we studied the ability of transglutaminase (TG) treatment of damaged wheat flour to return the functionality of the gluten network. To confirm the TG cross‐linking, the degree of protein hydrolysis, the amount of free thiol groups, and the electrophoresis properties of glutenin subunits were determined. The effectiveness of the TG treatment on insect‐damaged wheat was analyzed by measuring the dough mixing behavior and the gluten quality. A decrease in the degree of hydrolysis (or free amino groups), a reduction in thiol group concentration, and a decrease of extractable high molecular weight glutenin subunits (HMW‐GS) (measured by high‐performance capillary electrophoresis) confirmed the protein cross‐linking catalyzed by TG, the simultaneous formation of disulfide bonds by the proximity of the cross‐linked polypeptide chains, and the formation of aggregates of high molecular weight. The TG treatment of the damaged wheat flour led to a recovery of the consistograph parameters and gluten index value, and the covalent nature of the bonds ensured the stability of the protein changes.     

Information Literacy Across the Disciplines: Using the Science Information Literacy Wiki as a Collaborative Tool in Agriculture,Natural Resources,and Science Librarianship

The Association of College and Research Libraries (ACRL) Science and Technology Section (STS) wiki was launched in 2008. This article discusses the STS wiki development, content, publicity, and its application across the science disciplines. Information about assessment and future plans for the wiki is also provided. Some of the information included in this article was presented in a panel for the 2010 United States Agricultural Information Network (USAIN) Conference.