bluuebunny/crossref_metadata_2025 huggingface dataset:
Reaction Mechanism of Siderite Lump in Coal-Based Direct Reduction
Authors: Zhu Deqing , Luo Yanhong , Pan Jian , Zhou Xianlin
Published: April 2015

Siderite is one of the significant iron ore resources in China and yet is difficult to upgrade by traditional beneficiation processes. A process of coal-based direct reduction–magnetic separation was successfully developed for the beneficiation of siderite. However, few studies have thoroughly investigated the mechanism of the direct reduction of siderite. In order to reveal the reaction mechanism of coal-based direct reduction of siderite lump, thermodynamics of direct reduction was investigated with coal as the reductant. The thermodynamics results indicate that coal-based direct reduction process of siderite lump at 1,050°C follows the steps as FeCO3→ Fe3O4→ FeO → Fe, which is verified by chemical titration analysis, X-ray diffraction and scanning electron microscope. The microstructure of siderite sample varies with different reduction stages and some 45% porosity induced by thermal decomposition of siderite is conductive to subsequent reduction. The conversion of FeO to Fe is the main reduction rate-controlling step. The reduced product with the metallic iron size over 30 μm can be effectively beneficiated by wet magnetic separation after grinding. The obvious layered structure of reduced product is due to different heat transfer resistance, CO and CO2 concentration.
Optimization of Spray Drying Process Parameters for Sweet Corn Enzymolysis Liquid
Authors: Jiang Ning , Liu Chunquan , Li Dajing
Published: April 2015

The aim of this study was to optimize the spray drying process parameters for sweet corn enzymolysis liquid concentrate (SCELC). Experimental design with inlet temperature (170–190°C), SCELC/maltodextrin (MD) ratio (0.25–4) and inlet feed rate (800–1000 mL h−1) as independent variables was studied to investigate the effects on product responses. The corresponding results showed that an increase in the inlet temperature resulted in sweet corn powder with lower moisture, bulk density, L* value, H° value and higher water solubility index. Meanwhile, an increase in MD ratio brought lower moisture and higher L* value, H° value, water solubility index. It was also found that an increase in the inlet feed rate caused higher moisture and lower water solubility index. The highest production yield was achieved at 42.86% with optimized inlet temperature of 177.66°C, SCELC/MD ratio of 0.84 and inlet feed rate of 834.50 mL h−1. Accordingly, the production yield, moisture content, bulk density, water solubility index, L* and H° value were 42.86%, 3.57%, 0.45 g/cm3, 96.54 g/100 g, 84.46, and 83.54, respectively.
Linewidth Enhancement Factor and Amplification of Angle-Modulated Optical Signals in Injection-Locked Quantum Cascade Lasers
Authors: Chattopadhyay Taraprasad , Bhattacharyya Prosenjit
Published: April 2015

This paper presents a nonlinear analysis of the effect of linewidth enhancement factor (LEF) on the amplification of angle-modulated optical signals in injection-locked mid-infrared (IR) quantum cascade lasers (QCLs). A higher value of LEF tends to conserve the output angle modulation index of the amplified mid-IR signal particularly in the low-modulation frequency region. Further, a higher value of signal injection ratio produces a wider bandwidth of the locked QCL amplifier. The LEF introduces asymmetry in the lockband (LB) of the injection-locked QCL and this asymmetry increases with the increase in the value of LEF. Typically ratio of calculated lower-side LB to upper-side LB for an injection power level of – 20 dB and a LEF of unity is 1.67. The electron relaxation time in the uppermost subband lasing level in a three-level system has a profound effect on the LB asymmetry in a QCL.
To conquer a papyrus as a castle through an adverb: Linguistic traces of Caecilius Statius in a burnt papyrus from Herculanum and Horace
Authors: Calboli Gualtiero
Published: April 2015

Conceiving of a burnt papyrus from Herculanum as a medieval castle requires finding some keys for entry into this castle, though such a competent scholar as

Already in the title two parts of my paper are distinguished as keys to entering the castle, as I said, namely some references to Horace and another one concerning the castle, i.e. a burnt papyrus from Herculanum (Herc. 78) where one can suppose, and in particular Knut Kleve supposed, that Caecilius Statius’ Comedy
Habere + pp and the Origin of the Periphrastic Perfect
Authors: Hertzenberg Mari Johanne
Published: April 2015

In this paper, I discuss the use of
The Grammaticalization of Latin nē + Subjunctive Constructions
Authors: Lakey Holly A.
Published: April 2015

This paper looks at a network of constructions featuring the Latin particle
Computational valency lexica for Latin and Greek in use: a case study of syntactic ambiguity
Authors: McGillivray Barbara , Vatri Alessandro
Published: April 2015

We have built a corpus-driven valency lexicon for Greek verbs by following an approach devised for Latin data. We have then used the lexicon to detect a specific type of potentially ambiguous syntactic patterns in Latin and Greek hexametric poetry, which can consistently be disambiguated by prosodic breaks. Such disambiguating breaks were then mapped onto the metrical structure of the lines containing the ambiguous patterns, in order to assess their correspondence to metrical boundaries and to gather independent evidence on the phonetic nature of the boundaries themselves in view of further investigation. From a methodological point of view, the lexica have enabled us to draw on a relatively large set of texts to study a rare phenomenon and to establish a semi-automatic procedure that can be replicated on larger and compatible corpora.
An Improved Selection Test between Autoregressive and Moving Average Disturbances in Regression Models
Authors: Nguimkeu Pierre
Published: April 2015

This paper proposes an improved likelihood-based method to test the hypothesis that the disturbances of a linear regression model are generated by a first-order autoregressive process against the alternative that they follow a first-order moving average scheme. Compared with existing tests which usually rely on the asymptotic properties of the estimators, the proposed method has remarkable accuracy, particularly in small samples. Simulations studies are provided to show the superior accuracy of the method compared to the traditional tests. An empirical example using Canada real interest rate illustrates the implementation of the proposed method in practice.
Experimental impact study on unidirectional glass-carbon hybrid composite laminates
Authors: Julias A. Arockia , Murali Vela
Published: April 2015

In this experimental study, the impact response of unidirectional hybrid composite laminate was investigated. Hybrid laminates with different stacking sequences were fabricated, using unidirectional glass and carbon fiber as reinforcement and epoxy resin as matrix. ASTM standard D5628 was followed to conduct the experiment using the instrumented drop weight impact test apparatus. All the square specimens were tested at an impact velocity of 3.43 m/s and the time histories of force and energy absorbed were recorded. The impacted specimens and their X-ray images were visually inspected to understand the failure pattern. The experimental results showed that the addition of carbon fiber increases the impact strength by absorbing more force and energy. Furthermore, the laminate can be stiffened with the carbon fiber layers by interfacing glass fiber layers on either side.
Cardio-respiratory responses to standardized load resistance training in recreationally active participants
Authors: Mohamad Nur Ikhwan
Published: April 2015

This paper aims to determine acute responses of standardized resistance training load on cardio-respiratory variables in recreationally active participants. The methodology involved twelve recreationally active males with an age of 23.5 (± 4.07) years, a mass of 70.5 (± 7.84 kg), a height of 1.69 (± 0.06 m), and a body mass index of 24.8 (± 2.14) kg/m2). The participants performed an exercise protocol that comprises five exercises on a standardized load. Each exercise was performed in a duration of 60 seconds with uncontrolled lifting velocity. Cardio-respiratory responses were measured using a portable metabolic system analyzer during the exercises. A wrist digital blood pressure monitor was used to determine pre- and post-protocol blood pressure responses. Based on the results, pre- and post-protocol systolic (p=0.744) and diastolic (p=0.758) blood pressure indicated no significant responses. However, significant differences were observed in pre- and post-heart rate responses (p=0.000). Peak cardio-respiratory responses recorded during the protocol were 30.2 (± 4.02) ml/Kg/min for oxygen consumption, 138 (± 61.9) bpm for heart rate, and 633 (± 71.2) kcal for energy expenditure (estimated per hour). On average, the Metabolic Equivalent of Task (MET) was recorded at a value of 8.62 (± 1.19). For a short duration standardized load circuit training exercise protocol, cardio respiratory responses were similar to other protocols. The metabolic cost of the predefined exercises was nearly half of the recommended energy expenditure through exercise per week. The prescribed protocol was comparable with other exercise protocols for cardiorespiratory variables. The single set protocol used was efficient in terms of caloric expenditure, and was less strenuous over similar exercise duration. Furthermore, the prescribed protocol is applicable and beneficial for active and healthy individuals.
3D immersive environment as a psychological training tool to enhance self-confidence and reduce competitive anxiety for Malaysian volleyball athletes
Authors: Jing Tan Mei
Published: April 2015

Currently, great emphasis is placed on the development and intervention of psychology in sports in order to address the problem of athletes’ failure to achieve peak performance in actual competitions. This problem is primarily due to internal factors, such as anxieties, as well as external factors, such as the high pressure of the competitive environments athletes encounter. In this study, the cognitive anxiety, somatic anxiety and self confidence levels amongst elite and sub-elite Malaysian volleyball players are defined (male sample n = 50; female sample n = 35; age range between 17 to 25 years). These parameters were measured using the Competitive State Anxiety Inventory (CSAI-2), in which the questionnaires were completed by all respondents 30 minutes prior to the start of a competition. The findings indicated that there was a significant difference (p < 0.005) in cognitive anxiety, somatic anxiety and self-confidence among elite and sub-elite Malaysian (male and female) volleyball athletes. According to the findings, the competitive anxiety levels of the sub-elite athletes were higher than the elite, mainly due to the inability of the sub-elite athletes to control their emotions using psychological skills. In order to minimize this problem, a novel approach that involves using virtual reality to reduce the athletes’ competitive anxiety was proposed. This approach utilizes a 3D immersive environment that was developed based on the challenging real-world situations encountered during a volleyball match. The design and development of this approach is predicted to enhance athletes’ psychological skills, and in turn ensure that they can achieve peak performance under high pressure conditions.
A comparison of the physical fitness, athletic performance and competitive achievements of junior and senior tennis players
Authors: KURODA Yuta , SUZUKI Natumi , DEI Akimasa , UMEBAYASHI Kaoru , TAKIZAWA Kazuki , MIZUNO Masao
Published: April 2015

The Japan Tennis Association established the Tennis Field Test as a tool for aiding the development of effective coaching methods and improving the competitive achievements of individual elite tennis players. On the basis of such evaluations, specific coaching methods can be developed for individual tennis players. This study aims to evaluate the physical fitness and athletic performance of tennis players using the Tennis Field Test, and to compare these attributes between players of different ages and abilities. A total of 48 tennis players participated, of which 24 were junior players (including 15 regional representatives), and 24 were senior players (including 18 national representatives). The subjects were further subdivided into average and superior groups on the basis of their competitive achievements in regional or national tournaments. All subjects participated in the Tennis Field Test, which consists of the following six items: the number of sit-ups performed in 30 sec (an index of muscular endurance), the standing long jump distance (an index of leg power), the sit and reach test (an index of flexibility), the time taken to perform the spider run (an index of agility), the time taken to sprint 10 m (an index of speed), and the distance run in three minutes (an index of whole-body endurance capacity). In this study, the subjects’ sit and reach test data were not examined due to differences in the measurement methods used between junior and senior tennis players. Among the junior tennis players, the superior group performed faster in the spider run than the average group (p = 0.0011). Among the senior tennis players, the superior group achieved a longer mean distance during the three-minute run than the average group (p = 0.0223). The test results of the remaining items for both groups were relatively similar. This study suggests that competitive achievement is associated with agility among junior tennis players, and is associated with whole-body endurance capacity among senior tennis players.
Decision making and performance of Malaysian rugby sevens referees
Authors: Nizam Mohamad
Published: April 2015

This study aims to examine the decision making by rugby sevens referees, and its relationship with the referees’ performance. The instruments used in this study are the Rugby Referee Decision Making Test (α=.74) and the Referee Sevens Field Performance Evaluation (α=.94). It was administered to 132 rugby sevens referees (mean age 33.4 + 1.5 years; 132 males) from the Malaysian Rugby Union (MRU), which have been refereeing in 10 rugby sevens tournaments in Malaysia. Descriptive and Inferential statistics (one way ANOVA and Pearson’s Correlation) were employed to analyse the data. Decision Making ( = 24.13, SD= 5.24) and performance ( = 136.45, SD = 4.47) were identified at a moderate level. The findings indicated no significant differences [F= (3, 128) =.246, p>0.05] in the decision making across age level, but there were significant differences [F= (3, 128) =63.159, p<0.05] across experience level. Highly experienced referees scored significantly higher in all decision making constructs compared to less experienced referees. The research findings have revealed a positive and significant relationship between decision making (r= .61, p<.05) and referee performance. In conclusion, the decision making can help rugby sevens referees’ performance, and it is recommended that referees should increase the use of decision making in future training and assessment. Future research should investigate the effectiveness of decision making interventions in enhancing referees’ performance in the future.
Genome-Wide Association Study on Resistance to Stalk Rot Diseases in Grain Sorghum
Authors: Adeyanju Adedayo , Little Christopher , Yu Jianming , Tesso Tesfaye
Published: April 2015

Stalk rots are important biotic constraints to sorghum production worldwide. Several pathogens may be associated with the disease, but Macrophomina phaseolina and Fusarium thapsinum are recognized as the major causal organisms. The diseases become more aggressive when drought and high-temperature stress occur during grain filling. Progress in genetic improvement efforts has been slow due to lack of effective phenotyping protocol and the strong environmental effect on disease incidence and severity. Deployment of modern molecular tools is expected to accelerate efforts to develop resistant hybrids. This study was aimed at identifying genomic regions associated with resistance to both causal organisms. A sorghum diversity panel consisting of 300 genotypes assembled from different parts of the world was evaluated for response to infection by both pathogens. Community resources of 79,132 single nucleotide polymorphic (SNP) markers developed on the panel were used in association studies using a multi-locus mixed model to map loci associated with stalk rot resistance. Adequate genetic variation was observed for resistance to both pathogens. Structure analysis grouped the genotypes into five subpopulations primarily based on the racial category of the genotypes. Fourteen loci and a set of candidate genes appear to be involved in connected functions controlling plant defense response. However, each associated SNP had relatively small effect on the traits, accounting for 19–30% of phenotypic variation. Linkage disequilibrium analyses suggest that significant SNPs are genetically independent. Estimation of frequencies of associated alleles revealed that durra and caudatum subpopulations were enriched for resistant alleles, but the results suggest complex molecular mechanisms underlying resistance to both pathogens.
Tools forAnopheles gambiaeTransgenesis
Authors: Volohonsky Gloria , Terenzi Olivier , Soichot Julien , Naujoks Daniel A , Nolan Tony , Windbichler Nikolai , Kapps Delphine , Smidler Andrea L , Vittu Anaïs , Costa Giulia , Steinert Stefanie , Levashina Elena A , Blandin Stéphanie A , Marois Eric
Published: April 2015

Transgenesis is an essential tool to investigate gene function and to introduce desired characters in laboratory organisms. Setting-up transgenesis in non-model organisms is challenging due to the diversity of biological life traits and due to knowledge gaps in genomic information. Some procedures will be broadly applicable to many organisms, and others have to be specifically developed for the target species. Transgenesis in disease vector mosquitoes has existed since the 2000s but has remained limited by the delicate biology of these insects. Here, we report a compilation of the transgenesis tools that we have designed for the malaria vector Anopheles gambiae, including new docking strains, convenient transgenesis plasmids, a puromycin resistance selection marker, mosquitoes expressing cre recombinase, and various reporter lines defining the activity of cloned promoters. This toolbox contributed to rendering transgenesis routine in this species and is now enabling the development of increasingly refined genetic manipulations such as targeted mutagenesis. Some of the reagents and procedures reported here are easily transferable to other nonmodel species, including other disease vector or agricultural pest insects.
The Mosaic Mutants of Cucumber: A Method to Produce Knock-Downs of Mitochondrial Transcripts
Authors: Del Valle-Echevarria Angel R , Kiełkowska Agnieszka , Bartoszewski Grzegorz , Havey Michael J
Published: April 2015

Cytoplasmic effects on plant performance are well-documented and result from the intimate interaction between organellar and nuclear gene products. In plants, deletions, mutations, or chimerism of mitochondrial genes are often associated with deleterious phenotypes, as well as economically important traits such as cytoplasmic male sterility used to produce hybrid seed. Presently, genetic analyses of mitochondrial function and nuclear interactions are limited because there is no method to efficiently produce mitochondrial mutants. Cucumber (Cucumis sativus L.) possesses unique attributes useful for organellar genetics, including differential transmission of the three plant genomes (maternal for plastid, paternal for mitochondrial, and bi-parental for nuclear), a relatively large mitochondrial DNA in which recombination among repetitive motifs produces rearrangements, and the existence of strongly mosaic (MSC) paternally transmitted phenotypes that appear after passage of wild-type plants through cell cultures and possess unique rearrangements in the mitochondrial DNA. We sequenced the mitochondrial DNA from three independently produced MSC lines and revealed under-represented regions and reduced transcription of mitochondrial genes carried in these regions relative to the wild-type parental line. Mass spectrometry and Western blots did not corroborate transcriptional differences in the mitochondrial proteome of the MSC mutant lines, indicating that post-transcriptional events, such as protein longevity, may compensate for reduced transcription in MSC mitochondria. Our results support cucumber as a model system to produce transcriptional “knock-downs” of mitochondrial genes useful to study mitochondrial responses and nuclear interactions important for plant performance.
CYCLoPs: A Comprehensive Database Constructed from Automated Analysis of Protein Abundance and Subcellular Localization Patterns inSaccharomyces cerevisiae
Authors: Koh Judice L Y , Chong Yolanda T , Friesen Helena , Moses Alan , Boone Charles , Andrews Brenda J , Moffat Jason
Published: April 2015

Changes in protein subcellular localization and abundance are central to biological regulation in eukaryotic cells. Quantitative measures of protein dynamics in vivo are therefore highly useful for elucidating specific regulatory pathways. Using a combinatorial approach of yeast synthetic genetic array technology, high-content screening, and machine learning classifiers, we developed an automated platform to characterize protein localization and abundance patterns from images of log phase cells from the open-reading frame−green fluorescent protein collection in the budding yeast, Saccharomyces cerevisiae. For each protein, we produced quantitative profiles of localization scores for 16 subcellular compartments at single-cell resolution to trace proteome-wide relocalization in conditions over time. We generated a collection of ∼300,000 micrographs, comprising more than 20 million cells and ∼9 billion quantitative measurements. The images depict the localization and abundance dynamics of more than 4000 proteins under two chemical treatments and in a selected mutant background. Here, we describe CYCLoPs (Collection of Yeast Cells Localization Patterns), a web database resource that provides a central platform for housing and analyzing our yeast proteome dynamics datasets at the single cell level. CYCLoPs version 1.0 is available at http://cyclops.ccbr.utoronto.ca. CYCLoPs will provide a valuable resource for the yeast and eukaryotic cell biology communities and will be updated as new experiments become available.
Bibimys labiosus Winge, 1887 (Mammalia: Rodentia: Sigmodontinae): new records in Paraná state, southern Brazil, and update of the known geographic distribution
Authors: Grazzini Guilherme , Rezini Josias Alan , Santos Beatrice Stein Boraschi dos , Venâncio Fernando José , Gatto-Almeida Fernanda , Sbalqueiro Ives José , Hass Iris , Tiepolo Liliani Marilia
Published: April 2015

Bibimys is a genus still poorly known in its basic aspects, such as systematics, natural history and geographic distribution. In Brazil, only Bibimys labiosus is recorded, with occasional records spread in time and space. This paper presents four new localities of the species in Araucaria Forest, Paraná state, extending its distribution 150 km southwards. Additionally, a map of the known distribution of the species in Brazil and in Araucaria Forest is provided. The records point toward the lack of knowledge about basic aspects of the small non-flying mammal fauna in the plateau regions of Brazil.
Influência do estado nutricional de minicepas no enraizamento de miniestacas de eucalipto
Authors: Cunha Ana Catarina Monteiro Carvalho Mori da , Paiva Haroldo Nogueira de , Leite Helio Garcia , Barros Nairam Félix de , Leite Fernando Palha
Published: April 2015

O enraizamento adventício de estacas é influenciado por fatores intrínsecos e extrínsecos do material vegetal. O conhecimento sobre o modo de ação desses fatores sobre o enraizamento é fundamental para o sucesso da produção de mudas por miniestaquia. Entre os fatores envolvidos no enraizamento, pode-se destacar a nutrição mineral, pois existe significativa relação entre ela e o enraizamento. No entanto, a importância de vários nutrientes nesse processo ainda não está totalmente esclarecida. Diante do exposto, o objetivo deste trabalho foi avaliar o grau de associação linear entre o estado nutricional das minicepas com o enraizamento de miniestacas de eucalipto. Foram utilizados dados da empresa CENIBRA, entre os quais se analisaram os de enraizamento de miniestacas e dos teores de nutrientes revelados por análises químicas dos tecidos foliares das minicepas. Os dados usados foram originados de minijardim clonal cultivado em leito de areia, com fertirrigação por gotejamento. Com esses dados, foram realizadas análises para avaliar a existência de correlação linear entre as concentrações de macro e micronutrientes nas minicepas e a taxa de enraizamento das miniestacas. Os resultados indicaram que a nutrição mineral desempenha papel importante no enraizamento adventício das miniestacas produzidas pelas minicepas, gerando respostas diferenciadas de acordo com o nutriente considerado. Os resultados evienciaram que a solução nutritiva aplicada no minijardim clonal deve ser específica para cada clone.
Protein-mediated hydroxyapatite composite layer formation on nanotubular titania
Authors: Utku Feride Sermin , Yuca Esra , Seckin Eren , Goller Gultekin , Yazgan Karatas Ayten , Urgen Mustafa , Tamerler Candan
Published: April 2015

Realising controllable interactions at the bio-nanomaterial interfaces are vital in developing next-generation engineered implant materials. Titanium-based implants are key materials in biomedical engineering due to excellent bulk mechanical properties and biocompatibilities. Advanced bio-interfaces resolving nanostructured modulated surfaces that allow manipulation with the biological molecules is one of the keys to enhance favourable interactions with the surrounding biological species. Here, we developed a protein-mediated hydroxyapatite composite layer on nanotubular titania surface. Green fluorescence protein, engineered to contain hydroxyapatite binding peptides (GFPuv-HABP), was co-deposited with the hydroxyapatite precursors onto the titania nanotubes that are formed by anodisation. Ordered titanium dioxide nanotubular surfaces were coated with hydroxyapatite at physiological pH and temperature using simulated body fluid and pulsed electrochemical cathodisation. The hydroxyapatite deposit interdigitated into the nanotubes, producing a metal oxide-mineral composite. The engineered GFPuv-HABP protein was then self-assembled on the hydroxyapatite, forming a bio-modulated interface. Additionally, the engineered proteins were co-deposited with the precursor ions of hydroxyapatite mineral on the nanotubular titania plate. Bio-mediated assembly resulted in formation of a hybrid composite as an integrated interface on the nanotubular surface. Biomolecular assisted fabrication of hybrid composite interface on metal oxide substrate offers wide range of opportunities to design novel interfaces.
Pollen Thermotolerance of Upland Cotton Related to Anther Structure andHSPExpression
Authors: Song Guicheng , Jiang Chenliang , Ge Xiaoyang , Chen Quanzhan , Tang Canming
Published: April 2015

High temperature stress influences pollen grains development in upland cotton (Gossypium hirsutumL.) anthers, resulting in anthers with an abnormal structure and pollen grains with a low germination rate. To examine the thermotolerance mechanisms of pollen grains in upland cotton, we observed pollen germination rates, pollen grain ultrastructure, anther structure, and the expression of heat shock protein (HSP) genes in pollen grains after the plants were continuously exposed to high temperatures (36/30°C) in a phytotron for 8 h every day over a period of 10 d. After the high‐temperature treatment, the pollen germination percentage of the heat‐sensitive cultivar was reduced compared with the heat‐tolerant cultivar, and the structure of indehiscent anthers and the ultrastructure of pollen grains in the heat‐sensitive cultivar were more abnormal than that in the heat‐tolerant cultivar. There were more abnormal mitochondria, endoplasmic reticulum, and vacuoles as well as fewer starch granules in the pollen grains of the heat‐sensitive cultivar compared with the heat‐tolerant cultivar. The deformation of the pollen grain architecture may influence the pollen germination rate. The expression of theGhHSP90, GhHSP2, GhHSP7, andGhHSP8genes was up‐regulated to a greater extent in the heat‐sensitive pollen grains compared with the heat‐tolerant pollen during and after the high temperature period. The up‐regulation ofHSPgene expression may protect pollen grains from damage under high temperature stress (36/30°C). The structure of the anthers, ultrastructure of the pollen grains, and expression ofHSPgenes are related to the thermotolerance of pollen grains. These results provide a new approach for screening upland cotton cultivars for thermotolerance.
Nitrogen Rates and Sources Affect Yield and Profitability of Maize in Pakistan
Authors: Khan Amanullah , Almas Lal K. , Al‐Noaim Muhammad I.
Published: April 2015

Nitrogen is one of the most important factors affecting maize yield and profitability. To investigate the impact of N fertilizer sources (urea, calcium ammonium nitrate [CAN] and ammonium sulfate [AS]) applied in various amounts (0, 50, 100, 150, and 200 kg N ha−1) on grain yield and profitability of maize genotypes, local cultivars (Azam and Jalal) versus hybrid (Pioneer‐3025) field experiments were done during summer 2008–09 (Year 1) and 2009–10 (Year 2). The N yielded 41 and 26% more grain than the check in Year 1 and Year 2, respectively. In both years, grain yield increased in response to the increase in N application. Application of CAN and AS resulted in more grain yield than urea in Year 1, while no differences in yield were observed in Year 2. The hybrid (P‐3025) yielded 30 and 24% more grain than the average of local cultivars in Years 1 and 2, respectively. In Year 1, the net returns (NR) of PKR16262 ha−1 (one US$ = 95 Pakistani Rupees) was obtained with CAN but value cost ratio (VCR) of 3.7 was noticed with urea; in Year 2, both NR (PKR14271 ha−1) and VCR (3.1) was greatest with urea. In both years, the greatest NR was obtained with 100 and 150 kg N ha−1. Application of urea at 150 and 200 kg N ha−1, CAN at 100 and 150 kg N ha−1, and AS at 50 and 100 kg N ha−1 was economical in terms of NR in both years.
Soybean Aphid Populations on Aphid Resistant and Susceptible Soybean Lines Growing under Potassium Deficiency
Authors: Kates T. Michael , DiFonzo Christina , Wang Dechun
Published: April 2015

The soybean aphid is an important pest of soybean in North America. A positive link between soybean aphid population growth and potassium (K) deficiency, perhaps related to a higher free amino acid concentration in deficient plants, is generally accepted. At least one aphid resistance trait, Rag1, has a lower concentration of several free amino acids, and thus reduced nutritional quality. Since K appears to influence nutritional quality as well, the objective of this study was to determine if antibiosis resistance of two soybean aphid resistance traits was maintained under K deficiency. Over three seasons, aphid populations on resistant (LD05‐16060, Rag1; E06902, rag1b/rag3) and susceptible (SD01‐76R) lines were compared in field cages under K‐deficient and sufficient conditions. When lines were caged separately, the number of soybean aphids per plant on the susceptible line was significantly greater on deficient compared to fertilized plants. However, the Rag1 and rag1b/rag3 traits maintained resistance under the same conditions. When lines were caged together, and winged aphids from the susceptible line continuously deposited nymphs on the resistant lines, aphid populations on the resistant lines still remained far below the population on the susceptible line, and below the economic injury level of 674 soybean aphids per plant, under both K‐fertilized and K‐deficient conditions. Thus, resistance to soybean aphid was maintained in two soybean lines with different resistance genes, even when K was deficient.
Tracer Penetration into Welded Tuff Matrix from Flowing Fractures
Authors: Hu Qinhong , Kneafsey Timothy J. , Trautz Robert C. , Wang Joseph S. Y.
Published: April 2015

Field and laboratory tracer experiments were conducted to investigate the extent of tracer imbibition and penetration into unsaturated, fractured rock matrix at Yucca Mountain, Nevada. Field experiments were carried out in the Exploratory Studies Facility (ESF), an underground tunnel at Yucca Mountain. Water containing dye was released into horizontal boreholes drilled into the wall of the ESF main drift. The region was then mined to observe the flow pathways and to collect dye‐stained rock samples for subsequent laboratory quantification. Dye concentration profiles in the rock, measured using a newly developed sampling technique, showed that liquid flowing through the fractures penetrated into the matrix to a depth of several millimeters. Laboratory studies of tracer penetration into the rock matrix were conducted using tracer‐free rock samples, collected from the same hydrogeologic unit and machined into cylindrical cores. Tracer‐imbibition tests were performed on cores at two different initial water saturations with both sorbing (dyes) and nonsorbing tracers. The travel distance for sorbing dyes was a few millimeters after ∼16 to 20 h, similar to the extent measured in samples from the field test. The nonsorbing bromide front coincided with the wetting front in the rock core at the initial water saturation of 12%, and the imbibition depth agreed very well with the prediction, using independently measured properties. At the high initial water saturation of 76%, the bromide front lagged significantly behind the wetting front. Sorption coefficients for the dyes in the partially saturated core samples were calculated using two independent approaches, based on tracer travel‐distance and mass‐distribution calculations, and were found to yield comparable results. Utilization of nonsorbing tracers with different molecular sizes helped to identify the effects of pore‐size restriction on tracer transport during imbibition. The results from this work have a direct application to radionuclide transport at Yucca Mountain, and the methods presented are broadly applicable to the investigation of water and solute transport in unsaturated rock.
A Field Study of Water Flow and Virus Transport in Weathered Granitic Bedrock
Authors: Frazier C. S. , Graham R. C. , Shouse P. J. , Yates M. V. , Anderson M. A.
Published: April 2015

Where soils are shallow, effluents from on‐site wastewater disposal systems (OSWDS) can be dispensed onto underlying weathered bedrock. Viruses contained in the effluents pose a threat to groundwater quality if the weathered bedrock materials do not possess the properties necessary to treat the effluents before they reach groundwater. The extent and pathways of water flow and virus transport in fractured, weathered granitic bedrock were investigated at a field site in southern California. A suspension containing MS‐2 bacteriophage, sodium bromide, and blue dye was ponded at the soil–weathered bedrock interface and allowed to infiltrate for 9 h. A trench was excavated, and bedrock samples were collected and assayed for water, bromide, and MS‐2 content. Distributions of dye, bromide, and MS‐2 indicate that joint fractures facilitated the channeling of water and of viruses to depths >105 cm. Infiltration data suggest that fracture channeling occurred primarily during the first 50 min, after which time vertical convective flow through the bedrock matrix was the primary infiltration and transport process. The transition from fracture to matrix flow was the result of a decrease in fracture aperture caused by the swelling of pedogenic clay in the weathered bedrock matrix. Bromide and MS‐2 concentration profiles suggest that the lower extent of matrix flow was 45 cm, below which water flow and virus transport occurred solely via fracture channeling. These results indicate that caution should be used when operating OSWDS on weathered granitic bedrock in California, and emphasize the need to collect morphologic and hydraulic data prior to their installation.
Partitioning Tracer Tests for Characterizing Immiscible‐Fluid Saturations and Interfacial Areas in the Vadose Zone
Authors: Brusseau Mark L. , Nelson Nicole T. , Costanza‐Robinson Molly S.
Published: April 2015

Contaminant‐transport analyses, risk assessments, and site remediations are all constrained by the complexity of the subsurface environment and by our insufficient knowledge of that environment. Most current subsurface characterization methods provide measurements for very small spatial domains, such that they are essentially point values. While such methods can provide accurate and precise data for small scales, their use for characterizing larger domains is generally constrained by sample‐size limitations. Thus, methods that provide measurements at larger scales are being developed to complement the point‐sampling methods. One such group of methods is based on the use of tracer tests. This review will cover “partitioning” tracer tests, which can be used to measure immiscible‐liquid saturation of organic contaminants, soil water content, and fluid–fluid interfacial areas in subsurface systems. The conceptual basis and implementation of these methods will be briefly reviewed, with a focus on vadose zone applications.
Application of Gas‐Phase Partitioning Tracer Tests to Characterize Immiscible‐Liquid Contamination in the Vadose Zone Beneath a Fuel Depot
Authors: Brusseau Mark L. , Bronson Kali M. , Ross Stephanie , Nelson Nicole T. , Carlson Tyson D.
Published: April 2015

Gas‐phase partitioning tracer tests were conducted at a fuel depot to evaluate the utility of the partitioning tracer method for characterizing organic immiscible‐liquid contamination in the vadose zone. One test was conducted within the boundaries of an existing fuel dispensing island and former underground fuel tank facility. Core sampling indicated that the vadose zone at this location is heavily contaminated throughout its vertical extent by fuel‐related hydrocarbons. A tracer test was conducted after 30 mo of operation of a soil vapor extraction (SVE) system. Analysis of hydrocarbon concentrations in the SVE effluent indicates that approximately 355 000 L of hydrocarbons were recovered during the 30‐mo operation period. Comparing this value to the initial volume of hydrocarbons present, estimated to be approximately 454 000 L based on core data, produces an estimate of 99 000 (64 000–134 000) L of hydrocarbons remaining within the area influenced by the SVE system. Extrapolation of the tracer test results (Sn = 0.44%) to the SVE‐impacted zone produces an estimate of 107 000 (59 000–155 000) L of hydrocarbon present. The two values and associated approximate uncertainty ranges are relatively similar. The second test was conducted approximately 200 m from the former tank facility. Analysis of borehole material collected during well drilling at this location indicates minimal hydrocarbon contamination of the vadose zone, except in the vicinity of the water table (approximately 30 m below ground surface [bgs]), on which floating free product is found. Analysis of the tracer test results produced a hydrocarbon saturation value of 0.37%, which is significantly smaller than the initial value of approximately 1.9% (i.e., before SVE operation) estimated based on core data for the former tank facility location. The lower level of vadose‐zone contamination suggests that the source of immiscible‐liquid contamination found at the second location may be related to lateral migration of floating free product along the water table from the up‐gradient tank facility, rather than vertical migration from the surface above. However, additional studies would be required to more fully evaluate this hypothesis. The results of this work illustrate the utility of the gas‐phase partitioning tracer method for characterizing immiscible‐liquid contamination in the vadose zone.
Surfactant‐Induced Flow Phenomena in the Vadose Zone: A Review of Data and Numerical Modeling
Authors: Henry Eric J. , Smith James E.
Published: April 2015

Surfactants may occur naturally in the subsurface or may be introduced anthropogenically. Because of their ability to reduce surface tension and modify the solid–liquid contact angle, surfactants affect capillarity in unsaturated porous media. We review the current state of knowledge regarding surfactant effects on unsaturated flow and transport in water‐wetted porous media. Surfactant effects on moisture retention and unsaturated hydraulic conductivity are reviewed, as well as experimental evidence of surfactant effects on unsaturated flow. Surfactants can cause significant flow perturbations that do not occur in constant surface tension systems. Noteworthy effects include surfactant‐induced unsaturated flow that arises from surfactant concentration‐dependent surface tension gradients, as well as capillary fringe depression proportional to the surfactant‐induced relative reduction in surface tension. Most of the available data is from laboratory experiments; consequently, questions still remain about the relative importance of surfactant‐induced effects on field‐scale flow and transport processes. Numerical models that account for surfactant effects on flow provide useful tools for assessing the importance of these effects and should prove useful for designing surfactant‐based remedial schemes. We review simulations of unsaturated flow and transport in systems containing surfactants, as well as models that may be useful for conducting such simulations. Comparisons of simulated and experimental data indicate that hysteresis and dispersivity effects on simulation results can be important considerations. Future research directions should include the collection of additional field and laboratory‐scale data and expanded modeling efforts.
Lateral Water Diffusion in an Artificial Macroporous System: Modeling and Experimental Evidence
Authors: Castiglione P. , Mohanty B. P. , Shouse P. J. , Simunek J. , van Genuchten M. Th. , Santini A.
Published: April 2015

In two‐domain schematizations of macroporous soils or fractured rock systems, lateral mass exchange between macropores and the soil matrix is generally modeled as an apparent first‐order process. With respect to lateral diffusion, the system is thus characterized by a single parameter, the transfer rate coefficient, which is difficult to estimate a priori. We conducted water infiltration experiments in a laboratory column with an artificial macropore. The novel design of the experimental setup allowed us to discriminate between matrix flow and macropore flow, from which we could estimate the water exchange flux between the two domains. Most of the parameters in a dual‐permeability model could be determined independently of the experimental data. In particular, a theoretical expression for the transfer rate coefficient was derived by assuming lateral water and solute diffusion to be similar processes. Numerical analysis of the water exchange process revealed that the transfer coefficient depended also on the macropore conductivity. When this dependency was taken into account, the model reproduced the experimental data reasonably well.
Flexible Time Domain Reflectometry Probe for Deep Vadose Zone Monitoring
Authors: Dahan Ofer , McDonald Eric V. , Young Michael H.
Published: April 2015

Accurate determination of water content is an important aspect of most vadose zone monitoring programs. Real‐time, continuous, in situ measurements of water content in relatively undisturbed conditions are usually limited to shallow soil horizons. We present a new methodology using time domain reflectometry (TDR) for water content monitoring in deep vadose zone horizons. The method uses flat, flexible, waveguides pressed against the wall of a borehole. The flexible TDR waveguides are attached to the outer side of a flexible sleeve filled with a liquid resin. The resin (e.g., a two‐component urethane) generates hydrostatic pressure that forces the flexible waveguides against the borehole wall, ensuring a close fit to the irregular shape of the borehole walls. The probe can be used with either a standard TDR technique, which uses a cable tester (e.g., Tektronix 1520, Tektronix, Beaverton, OR) for collecting waveforms, or a water content reflectometer (e.g., model CS505, Campbell Scientific, Inc., Logan, UT), which provides a direct electrical output, which may be sampled using a data logger. Laboratory calibration experiments and a full‐scale field experiment showed that the method is reliable and capable of providing accurate water content measurements in deep vadose zone horizons.
A Conceptual Model of Unstable Flow in Unsaturated Soil during Redistribution
Authors: Jury William A. , Wang Zhi , Tuli Atac
Published: April 2015

A conceptual model is presented that represents the development of unstable flow in uniform soils during redistribution. The flow instability results in the propagation of fingers that drain water from the wetted soil matrix until equilibrium is reached. The model uses soil retention and hydraulic functions, plus relationships describing finger size and spatial frequency. The model assumes that all soils are unstable during redistribution, but shows that only coarse‐textured soils will form fingers capable of moving appreciable distances. Once it forms, a finger moves downward at a rate governed by the rate of loss of water from the soil matrix, which can be predicted from the hydraulic conductivity function. Fingers are assumed to stay narrow as a result of hysteresis, which prevents lateral diffusion. The draining front in the soil matrix between the fingers is assumed to cease downward movement because water pressure drops below the threshold water‐entry matric potential. The threshold potential is not present in the conventional Richards equation of soil water flow, which explains why unstable flow is not predicted by widely used simulation model codes.
Remediation of Technetium in Vadose Zone Sediments Using Ammonia and Hydrogen Sulfide Gases
Authors: Szecsody Jim E. , Truex Mike J. , Zhong Lirong , McKinley James P. , Qafoku Nikolla P. , Lee Brady D. , Saurey Sabrina D.
Published: April 2015

Technetium‐99 is a mobile, long‐lived radionuclide and environmental risk driver at some nuclear waste sites. The feasibility of decreasing 99Tc mobility in vadose zone sediments using H2S and NH3 gases was evaluated in laboratory experiments. In untreated sediments, 75 to 95% of the 99Tc was leachable. Using combinations of H2S and NH3 gases, the 99Tc mobility was reduced to 14 to 48%. Individual H2S or NH3 gas treatment of sediments had little lasting effect. For the combined gas treatment, the H2S gas created reducing conditions at the pore water–mineral interface, which temporarily reduced and precipitated 99Tc, while the NH3 gas created alkaline pore water that caused mineral dissolution. As the pH neutralized, subsequent aluminosilicate precipitation probably coated 99Tc precipitates and rendered them less mobile. Surface phase analysis showed that 99Tc was associated with weathered basalt clasts and S, possibly from the precipitation of TcSx. Treatment performance was nearly the same at different 99Tc concentrations (1.3–240.5 Bq g−1), water contents (1–8%), and gas injection rates but was sensitive to gas concentrations. Low gas concentrations (<3%) had insufficient reductant or slower mineral dissolution. High gas concentrations (>30%) formed an NH4SH precipitate. The 14 to 48% mobile 99Tc remaining after gas treatment may have been caused by the limited time for aluminosilicates to precipitate in our experiments. Degradation of added NH3 was not observed during the 3‐mo experiment. Overall, this study showed that combined H2S and NH3 gas treatment of low‐water‐content sediments can be applied to significantly decrease 99Tc mobility.