bluuebunny/crossref_metadata_2025 huggingface dataset:
Disruption of theprotein kinase Ngene ofDrosophila melanogasterResults in the RecessivedeloreanAllele (pkndln) With a Negative Impact on Wing Morphogenesis
Authors: Sass Georgette L , Ostrow Bruce D
Published: February 2014

We describe the delorean mutation of the Drosophila melanogasterprotein kinase N gene (pkndln) with defects in wing morphology. Flies homozygous for the recessive pkndln allele have a composite wing phenotype that exhibits changes in relative position and shape of the wing blade as well as loss of specific vein and bristle structures. The pkndln allele is the result of a P-element insertion in the first intron of the pkn locus, and the delorean wing phenotype is contingent upon the interaction of insertion-bearing alleles in trans. The presence of the insertion results in production of a novel transcript that initiates from within the 3′ end of the P-element. The delorean-specific transcript is predicted to produce a wild-type PKN protein. The delorean phenotype is not the result of a reduction in pkn expression, as it could not be recreated using a variety of wing-specific drivers of pkn-RNAi expression. Rather, it is the presence of the delorean-specific transcript that correlates with the mutant phenotype. We consider the delorean wing phenotype to be due to a pairing-dependent, recessive mutation that behaves as a dosage-sensitive, gain of function. Our analysis of genetic interactions with basket and nemo reflects an involvement of pkn and Jun-terminal kinase signaling in common processes during wing differentiation and places PKN as a potential effector of Rho1’s involvement in the Jun-terminal kinase pathway. The delorean phenotype, with its associated defects in wing morphology, provides evidence of a role for PKN in adult morphogenetic processes.
Traumatic Perforation of the Lamina Cribrosa During Nasal Intubation of a Preterm Infant
Authors: de Vries Maaike J. , Sival Deborah A. , van Doormaal-Stremmelaar Elisabeth F. , ter Horst Hendrik J.
Published: February 2014

Traumatic perforation of the lamina cribrosa and penetration of the brain occurred during nasotracheal intubation of a preterm infant requiring resuscitation. This rare complication is specifically associated with the nasal route of intubation. The complication resulted in significant morbidity. The infant developed an extensive intracranial hemorrhage and posthemorrhagic hydrocephalus that required ventricular drainage. We recommend that nasotracheal intubation be performed with utmost care. We confirm Cameron and Lupton’s recommendation of using a small feeding tube over which to slide the endotracheal tube. Despite extensive iatrogenic damage, the patient’s neurodevelopmental follow-up at 2 years 9 months appeared relatively mild.
Pulse Oximeter Sensor Application During Neonatal Resuscitation: A Randomized Controlled Trial
Authors: Louis Deepak , Sundaram Venkataseshan , Kumar Praveen
Published: February 2014

OBJECTIVE:

This study was done to compare 2 techniques of pulse oximeter sensor application during neonatal resuscitation for faster signal detection.

METHODS:

Sensor to infant first (STIF) and then to oximeter was compared with sensor to oximeter first (STOF) and then to infant in ≥28 weeks gestations. The primary outcome was time from completion of sensor application to reliable signal, defined as stable display of heart rate and saturation. Time from birth to sensor application, time taken for sensor application, time from birth to reliable signal, and need to reapply sensor were secondary outcomes. An intention-to-treat analysis was done, and subgroup analysis was done for gestation and need for resuscitation.

RESULTS:

One hundred fifty neonates were randomized with 75 to each technique. The median (IQR) time from sensor application to detection of reliable signal was longer in STIF group compared with STOF group (16 [15–17] vs. 10 [6–18] seconds; P <0.001). Time taken for application of sensor was longer with STIF technique than with STOF technique (12 [10–16] vs. 11 [9–15] seconds; P = 0.04). Time from birth to reliable signal did not differ between the 2 methods (STIF: 61 [52–76] seconds; STOF: 58 [47–73] seconds [P = .09]). Time taken for signal acquisition was longer with STIF than with STOF in both subgroups.

CONCLUSIONS:

In the delivery room setting, the STOF method recognized saturation and heart rate faster than the STIF method. The time from birth to reliable signal was similar with the 2 methods.
A Pacifier-Activated Music Player With Mother’s Voice Improves Oral Feeding in Preterm Infants
Authors: Chorna Olena D. , Slaughter James C. , Wang Lulu , Stark Ann R. , Maitre Nathalie L.
Published: February 2014

OBJECTIVES:

We conducted a randomized trial to test the hypothesis that mother’s voice played through a pacifier-activated music player (PAM) during nonnutritive sucking would improve the development of sucking ability and promote more effective oral feeding in preterm infants.

METHODS:

Preterm infants between 34 0/7 and 35 6/7 weeks’ postmenstrual age, including those with brain injury, who were taking at least half their feedings enterally and less than half orally, were randomly assigned to receive 5 daily 15-minute sessions of either PAM with mother’s recorded voice or no PAM, along with routine nonnutritive sucking and maternal care in both groups. Assignment was masked to the clinical team.

RESULTS:

Ninety-four infants (46 and 48 in the PAM intervention and control groups, respectively) completed the study. The intervention group had significantly increased oral feeding rate (2.0 vs 0.9 mL/min, P < .001), oral volume intake (91.1 vs 48.1 mL/kg/d, P = .001), oral feeds/day (6.5 vs 4.0, P < .001), and faster time-to-full oral feedings (31 vs 38 d, P = .04) compared with controls. Weight gain and cortisol levels during the 5-day protocol were not different between groups. Average hospital stays were 20% shorter in the PAM group, but the difference was not significant (P = .07).

CONCLUSIONS:

A PAM using mother’s voice improves oral feeding skills in preterm infants without adverse effects on hormonal stress or growth.
Inpatient Bronchiolitis Guideline Implementation and Resource Utilization
Authors: Mittal Vineeta , Darnell Cindy , Walsh Brian , Mehta Amit , Badawy Mohamed , Morse Rustin , Pop Rodica , Tidwell Jerithea , Sheehan Maeve , McDermott Sandra , Cannon Carolyn , Kahn Jeffrey
Published: February 2014

BACKGROUND:

Provider-dependent practice variation in children hospitalized with bronchiolitis is not uncommon. Clinical practice guidelines (CPGs) can streamline practice and reduce utilization however, CPG implementation is complex.

METHODS:

A multidisciplinary team developed and implemented CPGs for management of bronchiolitis for children <2 years old. Children with comorbidities, ICU admissions, and outside hospital transfers were excluded. Implementation involved teamwork and collaboration, provider education, online access to CPGs, order sets, data sharing, and monthly team meetings. Resource utilization was defined as use of chest x-rays (CXRs), antibiotics, steroids, and more than 2 doses of inhaled bronchodilator use. Outcome metrics included length of stay (LOS) and readmission rate. Bronchiolitis season was defined as September to April. Data were collected for 2 seasons post implementation.

RESULTS:

The number CPG-eligible patients in the pre- and 2 postimplementation periods were similar (1244, preimplementation; 1159, postimplementation season 1; 1283 postimplementation season 2). CXRs decreased from 59.7% to 45.1% (P < .0001) in season 1 to 39% (P < .0001) in season 2. Bronchodilator use decreased from 27% to 20% (P < .01) in season 1 to 14% (P < .002) in season 2. Steroid use significantly reduced from 19% to 11% (P < .01). Antibiotic use did not change significantly (P = .16). LOS decreased from 2.3 to 1.8 days (P < .0001) in season 1 and 1.9 days (P < .05) in season 2. All-cause 7-day readmission rate did not change (P = .45).

CONCLUSIONS:

Bronchiolitis CPG implementation resulted in reduced use of CXRs, bronchodilators, steroids, and LOS without affecting 7-day all-cause readmissions.
Obesity in Pediatric ALL Survivors: A Meta-Analysis
Authors: Zhang Fang Fang , Kelly Michael J. , Saltzman Edward , Must Aviva , Roberts Susan B. , Parsons Susan K.
Published: February 2014

BACKGROUND AND OBJECTIVE:

Previous studies of survivors of pediatric acute lymphoblastic leukemia (ALL) have drawn heterogeneous conclusions regarding the prevalence of obesity and risk factors for developing obesity in pediatric ALL survivors. We sought to determine the prevalence of obesity in pediatric ALL survivors and examine risk factors for obesity through a systematic review and meta-analysis.

METHODS:

A MEDLINE search was performed from its inception through 2013. Studies met the inclusion criteria if they (1) included at least 10 survivors of pediatric ALL; (2) assessed the prevalence or indicators of obesity; and (3) compared obesity among ALL survivors to a reference population or external control group. Extracted data included patient and treatment characteristics, study design, population used for comparison, and prevalence of obesity.

RESULTS:

Forty-seven studies met the inclusion criteria. Despite significant heterogeneity among the studies (I2 = 96%), the mean BMI z score in 1742 pediatric ALL survivors was 0.83 (95% confidence interval: 0.60–1.06), which corresponds to the 80th BMI percentile, indicating a significantly higher BMI in pediatric ALL survivors than the reference population. Subgroup analyses found a high prevalence of obesity in ALL survivors regardless of survivors’ receipt of cranial irradiation, gender, or age at diagnosis.

CONCLUSIONS:

Obesity is prevalent in pediatric ALL survivors and is independent of patient- and treatment-related characteristics. Clinicians need to screen for obesity and its associated health conditions early in survivorship.
Atomic-layer Deposition for Improved Performance of III-N Avalanche Photodiodes
Authors: Hennessy John , Bell L. Douglas , Nikzad Shouleh , Suvarna Puneet , Leathersich Jeffrey M. , Marini Jonathan , Shahedipour-Sandvik F. (Shadi)
Published: February 2014

We have investigated surface modification methods for avalanche photodiodes using dielectrics deposited by atomic layer deposition (ALD). Arrays of mesa GaN APDs were fabricated, and ALD Al2O3 was used for sidewall passivation prior to completing the APD array. The use of ALD Al2O3 in this manner was observed to result in a large average improvement in APD dark current when compared with devices using more conventional SiO2 passivation layers produced by chemical vapor deposition. Co-processed metal-oxide-semiconductor (MOS) capacitors fabricated with the same passivation layers show significant improvement in electrical interface quality for devices with ALD Al2O3.
Ultraviolet Photodetector Fabricated from 3D WO3 Nanowires/Reduced Graphene Oxide Composite Material
Authors: Shao Dali , Yu Mingpeng , Lian Jie , Sawyer Shayla
Published: February 2014

An Ultraviolet (UV) photodetector with high responsivity and relative fast response speed was fabricated from three dimensional WO3 nanowires/reduced graphene oxide (3D WO3 NWs/RGO) composite materials. The 3D WO3 NDs/GN composite was synthesized using a facile three-step synthesis. First, the Na2WO4/Graphene Oxide (GO) precursor was synthesized by homogeneous precipitation. Second, the Na2WO4/GO precursor was transformed into H2WO4/GO composites by acidification. Finally, the H2WO4/GO composites were reduced to 3D WO3 NWs/RGO via hydrothermal reduction process. A maximum photoresponsivity of 4.2 A/W at 374 nm was observed under 20 V bias. The UV photodetector showed relative fast transient response, which is at least 2 orders of magnitude faster than UV photodetectors fabricated from WO3 nanowires. The good photoresponsivity and fast transient response are attributed to improved carrier transport and collection efficiency through graphene.
Effects of Coulomb Impurity in Semiconductor Nanowire
Authors: Tchelidze Tamar , Kereselidze Tamaz , Nadareishvili Teimuraz
Published: February 2014

We present calculation of electronic structure of impurity in nanowire. Ionization energy of impurities are calculated in dependence on nanowire radius. Direct Hamiltonian matrix diagonalization method with the physically reasonable approximate potential is employed for finding the exact solution of Schrödinger equation in the effective-mass approximation. It is shown that shallow donors are strongly influences by space confinement, which is expressed in sharp increase of ionization energy. Calculations show that effect of space confinement on deep impurities is less pronounced. The obtained results give hope that by selecting optimal value of nanowire radius compensation processes can be suppressed.
Investigation of migration behavior of rod-like dsDNA in gel with precisely controlled network structure
Authors: Li Xiang , Khairulina Kateryna , Chung Ung-il , Sakai Takamasa
Published: February 2014

We investigated the migration behavior of rodlike double-stranded DNA (dsDNA) in polymer gels and polymer solutions. Tetra-PEG gel, which has a homogeneous network structure, was utilized as a model system, allowing us to systematically tune the polymer volume fraction and molecular weight of network strand. Although we examined the applicability of the existing models, all the models failed to predict the migration behavior. Thus, we proposed a new model based on the Ogston model, which well explained the experimental data of polymer solutions and gels. The polymer volume fraction determined the maximum mobility, while the network strand governed the size sieving effect. From these results, we conclude that the polymer network with lower polymer volume fraction and smaller network strand is better in terms of size separation. The homogeneous polymer network is vital for understanding of particles’ dynamics in polymer network and a promising material for high-performance size separation.
High resistivity isolation for AlGaN/GaN HEMT using Al double-implantation
Authors: Taube Andrzej , Kozubal Maciej , Kaczmarski Jakub , Juchniewicz Marcin , Barcz Adam , Dyczewski Jan , Jakieła Rafał , Dynowska Elżbieta , Borysiewicz Michał Adam , Prystawko Paweł , Jasiński Jakub , Borowicz Paweł , Kamińska Eliana , Piotrowska Anna
Published: February 2014

The paper reports on the fabrication of electrical isolation for planar AlGaN/GaN high electron mobility transistor using Al double-implantation. The implantation was performed using Al+ ions with energies of 800 keV and 300 keV with doses of 1.5×1013 ion/cm2 and 1×1013 ion/cm2, respectively. Electrical measurements have shown that after implantation the sheet resistance was 1.8×1011 Ω/□ and increased to 1.17×1014 Ω/□ and 3.29×1012 Ω/□ after annealing at 400°C and 600°C respectively. Annealing at 800°C decreased the sheet resistance to 1.38×108 Ω/□. Characterization by XRD, Raman and photoluminescence spectroscopy give evidence that implantation damages the crystal lattice, yielding insulating properties. It has been demonstrated that the isolation is stable up to 600°C.
Depression, sense and sensitivity: On pre-diagnostic questioning about self-harm and suicidal inclination in the primary care consultation
Authors: Miller Paul Kenneth
Published: February 2014

National Health Service directives in the UK specify that, in any primary care consultation where a patient either demonstrably has – or is suspected to have –depression, a ‘direct question’ should be asked regarding their thoughts or activities relating to selfharm or suicide. The evidence collected for this study, which takes the form of recorded interactions between doctors and patients in primary care settings, indicates that this is most commonly done post-diagnosis as an exercise in ‘risk assessment’. Suicidal ideation, however, is not only classified as a possible outcome of depression but also a core symptom of the condition and, consequently, such a question is sometimes asked prior to the diagnostic phase of the consultation, as a key step in reaching a depression diagnosis. This specific activity presents a general practitioner with an inferably difficult communicative task: how to raise the matter of suicide/self-harm when the patient does not already have a depression diagnosis as an interactional resource with which to make sense of its local relevance. Herein, using a conversation analytic method, techniques employed by general practitioners and patients in negotiating three of these potentially sensitive moments are examined. Analytic observations are then used to highlight a range of issues pertinent to the formulation of normative frames of ‘good practice’ in handling difficult clinical topics in situ.
Stress management: Corpus-based insights into vernacular interpretations of stress
Authors: Stvan Laurel Smith
Published: February 2014

Examination of the term stress in naturally occurring vernacular prose provides evidence of three separate senses being conflated. A corpus analysis of 818 instances of stress from non-academic texts in the Corpus of Contemporary American English (COCA) and the Corpus of American Discourses on Health (CADOH) shows a negative prosody for stress, which is portrayed variously as a source outside the body, a physical symptom within the body and an emotional state. The data show that contemporary speakers intermingle the three senses, making more difficult a discussion between doctors and patients of ways to ‘reduce stress’, when stress might be interpreted as a stressor, a symptom, or state of anxiety. This conflation of senses reinforces the impression that stress is pervasive and increasing. In addition, a semantic shift is also refining a new sense for stress, as post-traumatic stress develops as a specific subtype of emotional stress whose use has increased in circulation in the past 20 years.
Causas de remocao nao eletiva do cateter epicutaneo em neonatos
Authors: Paiva Eny Dorea , Costa Priscila , Kimura Amelia Fumiko , Castro Talita Elci de
Published: February 2014

Objetivou-se descrever a incidência e as razões de remoção não eletiva do cateter epicutâneo em neonatos, verificando a associação com o sítio de inserção. Estudo de coorte prospectivo realizado em unidade de cuidado intensivo neonatal de um hospital privado terciário na cidade de São Paulo. Foram analisadas 266 inserções de cateter epicutâneo. A incidência de remoção não eletiva foi 39,1%. As complicações pós-inserção mais frequentes foram suspeita de infecção de corrente sanguínea relacionada ao cateter (25%) e ruptura (23,1%). A maioria dos cateteres foi inserida através do hemisfério corporal direito (65%), membros superiores (77,1%) e veias axilares (31,2%). Os resultados sugerem não haver associação entre a incidência de remoção não eletiva e o sítio de inserção do cateter epicutâneo em neonatos. Compete à Enfermagem implementar estratégias para a melhoria da prática assistencial a fim de diminuir a frequência de remoções não eletivas do cateter epicutâneo em neonatos.
Motivação dos alunos para a utilização da tecnologia wiki: um estudo prático no ensino superior
Authors: Costa Carolina , Alvelos Helena , Teixeira Leonor
Published: February 2014

No âmbito do processo ensino-aprendizagem (EA), os wikis permitem ajudar na criação de um ambiente dinâmico e colaborativo de aprendizagem, por meio da comunicação, troca de ideias e partilha de conhecimento. O presente trabalho faz parte de um projeto cujo intuito é avaliar a aceitação do uso dessa tecnologia como meio de promoção da qualidade do processo EA. Em particular, o estudo descrito neste artigo tem como objetivo avaliar a motivação para a utilização de wikis por parte de um grupo de alunos da área tecnológica do ensino superior e compará-la entre os alunos que pretendem continuar fazendo uso da ferramenta em atividades futuras e os que não planejam usar a tecnologia. Essa experiência foi feita em contexto de sala de aula e os dados foram obtidos através da aplicação de dois questionários e da análise do histórico do wiki criado para a atividade desenvolvida em classe. Os resultados revelaram que os alunos, apesar de conhecerem a ferramenta, desconheciam, na prática, o seu modo de edição. As características dos wikis mais bem classificadas pelos alunos se relacionam com a facilidade de utilização percebida e com a utilidade da ferramenta, na medida que em promove a aprendizagem por meio de conteúdos colocados pelos outros e a realização de trabalhos de grupo sem depender da presença física nem dos horários dos seus elementos. Verificou-se, ainda, que a motivação para o uso dos wikis revelou-se, em alguns itens, significativamente diferente entre os grupos comparados.
Resistance to “Castration-Resistant”
Authors: Luzzatto Lucio
Published: February 2014

The author challenges the use of the phrase “castration resistance,” which is widely used in the literature and also appears in a recent article by Merseburger et al.
In Reply
Authors: Merseburger Axel S. , Bellmunt Joaquim , Jenkins Cheryl , Parker Chris , Fitzpatrick John M.
Published: February 2014

Merseburger, Bellmunt, Jenkins et al. respond to Dr. Luzzatto's letter regarding the use of the term “castration resistant” in describing the progression of prostate cancer.
Lessons learnt from installation of field instrumentation
Authors: Wan Michael S. P. , Standing Jamie R.
Published: February 2014

Imperial College in London, UK, as part of an Engineering and Physical Sciences Research Council (EPSRC) funded research project and in collaboration with Crossrail urban railway project, is performing field monitoring research to investigate how tunnelling affects existing tunnels. Comprehensive instrumentation was installed in Hyde Park and bordering Bayswater Road, beneath which the new Crossrail tunnels were constructed in London Clay below the existing London Underground Central Line tunnels. Surface and subsurface instruments were installed around the Crossrail tunnel alignments to monitor the ground response to the tunnel construction. Monitoring systems of sufficient resolution and accuracy were adopted to achieve high-quality data for assessing the tunnelling-induced ground response and mechanisms of movement from earth-pressure-balance machine tunnelling. The installation of surface and subsurface instrumentation took place in the summer of 2011. This paper describes and discusses the installation of rod extensometers, in-place inclinometers and multi-level vibrating-wire borehole piezometers. Selection of the appropriate cement–bentonite grout mixes for backfilling these borehole instruments is discussed, as this is critical for representative measurements of ground response. Some practical challenges arising during the installation process and how they were overcome are also described. Confidence in the instrument performance is demonstrated using example monitoring results from the piezometer and extensometer installations.
Becoming a Peer-Reviewed Journal
Authors: Manthey Marie
Published: February 2014

Marie Manthey, founder of Creative Nursing, reviews the history of the publication and announces its new status as a peer-reviewed journal.
How Experienced Practitioners
Authors: Vaughan Barbara
Published: February 2014

An evolution in nursing in the United Kingdom in the 1970s from rule-bound toward holistic, autonomous practice engendered an examination of nursing's body of knowledge and how it is incorporated into practice. This article describes Barbara Carper's (1978) Fundamental Patterns of Knowing in Nursing (empiric, ethical, aesthetic, and personal knowledge), and links it to three major worldviews of the way in which knowledge is sought (positivism, naturalism, and critical social theory). Carper's model was used in the United Kingdom as the basis for a curriculum of structured reflective practice using workshops, journaling, and clinical supervision. An example from a practitioner's diary demonstrates how Carper's model informs reflection on an interaction with a patient with newly diagnosed cancer.
Resistance of Poncirus and Citrus × Poncirus Germplasm to the Asian Citrus Psyllid
Authors: Richardson Matthew L. , Hall David G.
Published: February 2014

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, has spread to citrus growing regions nearly worldwide and transmits phloem‐limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease. Host plant resistance may provide the most effective control, but ACP has a broad host range and resistance in Citrus spp. and relatives to ACP has not been widely documented. Very low abundances of ACP were found on two accessions of Poncirus trifoliata (L.) Raf. (hardy‐orange) in a field survey. Therefore, we tested whether 81 accessions of P. trifoliata and ×Citroncirus spp. (hybrids of P. trifoliata and Citrus spp.) from the USDA‐ARS National Clonal Germplasm Repository for Citrus and Dates were resistant to ACP by determining whether these accessions influence oviposition and lifespan of adults in no‐choice tests. There was a higher abundance of eggs on the control (Citrus macrophylla Wester [alemow]) than nearly all accessions of P. trifoliata, and zero eggs were laid on 36% of the accessions. Additionally, more eggs were laid on the control than 10 of 34 accessions of ×Citroncirus spp. Lifespan of adults was approximately 2.5 to 5 times longer on 11 of the 17 trifoliates and trifoliate hybrids we tested. Poncirus trifoliata appears to have antixenosis and antibiosis resistance to ACP, but we must next identify the traits that promote resistance to create commercial varieties of citrus that reduce the population of ACP and lower the incidence of citrus greening disease.
Identification of Aluminum Tolerance Quantitative Trait Loci in Tetraploid Alfalfa
Authors: Khu Dong‐Man , Reyno Rafael , Han Yuanhong , Zhao Patrick X. , Bouton Joseph H. , Brummer E. Charles , Monteros Maria J.
Published: February 2014

Aluminum (Al) toxicity in acid soils is one of the factors limiting crop production. Alfalfa (Medicago sativa L.) is the most important forage legume worldwide and is susceptible to Al toxicity. Our objective was to identify genomic regions associated with Al tolerance in tetraploid alfalfa. A segregating population obtained from a cross between Altet‐4 (Al‐tolerant genotype) and NECS‐141 (Al‐sensitive genotype) was evaluated for Al tolerance using a callus bioassay and a whole plant assay in media and genotyped using molecular markers. Phenotyping results for both callus and root growth assays exhibited a normal distribution and patterns of transgressive segregation. The linkage maps covered 761 cM for Altet‐4 and 721 cM for NECS‐141. Markers associated with Al tolerance from both assays were detected using single‐factor analysis. Quantitative trait loci (QTL) for Al tolerance were identified on linkage groups (LGs) 1, 4, and 7 using interval mapping, and these QTL explained 20.8, 15.2, and 21.7% of the variation, respectively. A second population was used to evaluate the identified Al tolerance QTL in a different genetic background. Although mechanisms of Al tolerance in tetraploid alfalfa are quantitative, the identification of relevant genomic regions and candidate genes involved in abiotic stress responses can facilitate the selection of desirable alleles to accelerate the development of alfalfa cultivars that can be productive in acid and Al‐toxic soils.
Double‐Neutral Genes, Sa‐n and Sb‐n, for Pollen Fertility in Rice to Overcome Indica × Japonica Hybrid Sterility
Authors: Shahid Muhammad Qasim , Chen Feng‐Yi , Li Hong‐Yan , Wang Si‐Zhe , Chen Peng‐Fei , Lin Shun‐Quan , Liu Xiang‐Dong , Lu Yong‐Gen
Published: February 2014

A major obstacle in the development of superior intersubspecific hybrids between subspecies (indica and japonica) of Asian cultivated rice (Oryza sativa L.) is partial sterility of the F1 generation. Neutral genes, Sa‐n, Sb‐n, and Sc‐n, for pollen fertility have the potential to overcome F1 pollen sterility. The present study was planned to find double‐neutral genes for pollen fertility and to evaluate their effect on pollen fertility of intersubspecific hybrids. Five genotypes were crossed with eight isogenic lines to mine neutral genes for pollen fertility. Pollen fertility of hybrids was observed in F1 and F2, and segregation ratios were recorded in F2 to confirm the neutral genes. The results showed that DN18 and DN75 had double‐neutral genes (Sa‐n and Sb‐n) whereas DN22 had three neutral genes Sa‐n, Sb‐n, and Sc‐n at Sa, Sb, and Sc pollen sterility loci, respectively. Furthermore, we found a single neutral gene (Sc‐n) for pollen fertility at the Sc locus and neutral gene for embryo sac fertility at the S5 locus in DN13. DN18 and DN75 were crossed with numerous typical japonica and indica cultivars. Results showed that double‐neutral genes could overcome most of the intersubspecific hybrid pollen sterility. These lines could be used for the development of high yielding indica × japonica hybrids and neutral genes could be introgressed into elite cultivars of Asian cultivated rice for fertility restoration.
Modeling Soil Water Redistribution during Second‐Stage Evaporation
Authors: Suleiman A. A. , Ritchie J. T.
Published: February 2014

Calculating the dynamics of soil water content (θ) near the surface and modeling soil water evaporation (Es) are critical for many agricultural management strategies. This study was performed to develop a model to simulate soil water redistribution during second‐stage evaporation (SSE). In this model, the daily change of θ was estimated from the difference between the initial θ (θi) and air‐dry θ (θad), multiplied by a conductance coefficient (C). The C represents the fraction of the remaining soil water (θi − θad) that can be removed in 1 d during SSE and is a power function of soil depth. Testing the dependency of C and α (the slope of cumulative evaporation [Ec] vs. square root of time [t1/2]) on soil characteristics was done using theoretical and laboratory data. Then the whole model was evaluated in laboratory and field conditions by measuring θ for different soils at different depths during SSE. Linear relationships with zero intercept were found between α and drained upper limit θ (θdul) with slope and r2 = 1.19 and 0.69 and 1.39 and 0.95 for laboratory and theoretical data, respectively. Conductance coefficient and θdul were correlated with r2 > 0.9. Root mean square error (RMSE) between measured and estimated θ in the field was highest (0.014 cm3 cm−3) at depths of 3 and 6 cm and lowest (0.005 cm3 cm−3) at the 9‐cm depth. The model gave reasonable estimates of both water redistribution and Es during SSE and is expected to work well for soils for which the diffusivity theory holds.
Root‐System Development and Water‐Extraction Model Considering Hydrotropism
Authors: Tsutsumi D. , Kosugi K. , Mizuyama T.
Published: February 2014

A two‐dimensional model that combines root‐system development and water extraction by roots is proposed to simulate the dynamic interaction between root growth and soil‐water flow. Both of hydrotropism and gravitropism were considered as the controlling factors of root growth in the proposed root‐system development model. The finite‐element method was employed to compute the soil‐water flow caused by water extraction, evaporation, and irrigation. We succeeded in simulating the plagiogravitropic elongations of lateral roots under a plane condition, and the asymmetric architecture of root system under a slope condition by the proposed model in which the root hydrotropism is considered. On the other hand, we cannot simulate such morphological characteristics of a root system by the use of the conventional model in which a random elongation factor is employed, and root hydrotropism is not considered. The results support the importance of hydrotropism in root‐system development and the availability of the proposed model in which the hydrotropism is considered.
Long‐term Movement of a Chloride Tracer under Transient, Semi‐Arid Conditions
Authors: Dyck M. F. , Kachanoski R. G. , de Jong E.
Published: February 2014

Understanding the magnitude and variability of water and solute fluxes in the vadose zone is required to assess the risk of potential contamination of ground water resources. In this study, the long‐term (>30 yr) movement of a Cl tracer applied to the soil surface is quantified. In 1966, granular KCl was applied to the surface of nine 6 by 90 m plots at a field site near Saskatoon, Saskatchewan. Additional KCl was applied to two of the plots in 1970. Application rates varied between 0.11 to 2.24 kg KCl m−2 Moment analysis was used to calculate the mean travel depth (E[z]) and variance (V[z]) of depth breakthrough curves compiled from soil samples taken 1, 2, 3, 4, 28, and 34 yr after the initial KCl application from the 2.24‐kg KCl m−2 plot. Spatial variability of Cl transport was assessed on 51 cores taken along a 10‐m transect, 34 yr after application. Initial movement of the tracer through the root zone was relatively quick (E[z] = 1.34 m, 4 yr after application), followed by slow movement (E[z] = 1.68 m, 34 yr after application). The change in E[z] between 4 and 34 yr after application was used to calculate a velocity below the root zone of 11 mm yr−1 and a deep drainage estimate of 3 mm yr−1 (θ = 0.3) which is within the range of other estimates for the Canadian Prairies. Variability in E[z] along the 10‐m transect, after 34 yr of transport was low (coefficient of variation [CV] = 4%), suggesting relatively uniform deep drainage. This contrasts sharply with the high variation in convective fluxes measured in other steady‐state high‐flow field‐tracer experiments.
Phosphorus‐31 Nuclear Magnetic Resonance Spectral Assignments of Phosphorus Compounds in Soil NaOH–EDTA Extracts
Authors: Turner Benjamin L. , Mahieu Nathalie , Condron Leo M.
Published: February 2014

Soil P composition can be conveniently determined in alkaline extracts using solution 31P nuclear magnetic resonance (NMR) spectroscopy, but spectral assignments are based on fragmentary literature reports of model compounds in various extraction matrices. We report solution 31P NMR chemical shifts of model P compounds, including inorganic phosphates, orthophosphate monoesters and diesters, phosphonates, and organic polyphosphates, determined in a standardized soil P extractant (0.25 M NaOH and 0.05 M EDTA). Signals from nucleic acids (DNA −0.37 ppm, RNA 0.54 ppm) and phospholipids (phosphatidyl choline 0.78 ppm, phosphatidyl serine 1.57 ppm, phosphatidyl ethanolamine 1.75 ppm) could be differentiated in the orthophosphate diester region, and were identified in a sample of cultured soil bacteria. Inorganic and organic polyphosphates could be differentiated by the presence of a signal at −9 ppm from the α phosphate of organic polyphosphates. Some orthophosphate diesters, notably RNA and phosphatidyl choline, degraded rapidly to orthophosphate monoesters in NaOH–EDTA although DNA, other phospholipids, and orthophosphate monoesters were more stable. Changes in probe temperature had a marked influence on signal intensities and the relative magnitude of signals from orthophosphate monoesters and inorganic orthophosphate, and we suggest that solution 31P NMR spectroscopy of soil extracts be performed at 20°C.
Use of Organosmectites to Reduce Leaching Losses of Acidic Herbicides
Authors: Carrizosa M. J. , Hermosin M. C. , Koskinen W. C. , Cornejo J.
Published: February 2014

The modification of smectitic clays with organic cations via cation‐exchange reactions produces sorbents with an increased sorption capacity for organic compounds such as acidic herbicides. These organoclays (OCls) could be used as carriers in controlled release formulations of herbicides to decrease their contamination potential. Various OCls and two acidic herbicides (bentazone [3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4 (3H) one 2,2‐dioxide] and dicamba [2‐methoxy‐3,6‐dichlorobenzoic acid]) were selected and herbicide–OCl complexes were prepared by either sorbing the herbicides on the OCl from solution or by dry mixing of both components. Those preparations were assayed as controlled‐release formulations under static (water solution) and dynamic (soil column leaching) conditions. Herbicide release in closed (static) systems was fast and reached a maximum concentration after 10 to 20 h. The total herbicide released ranged from 20 to 100% of the active ingredient initially incorporated in the complex depending on the sorption capacity of the OCl for the herbicide and the strength of herbicide–OCl interaction (aging time). Complexes releasing <50% of the herbicide, corresponding to the most sorptive OCls, may not be appropriated for weed control. Total leaching losses in soil columns were reduced from 94% for free technical bentazone to 55 to 90% for bentazone‐OCl complexes, and from 100% for technical dicamba to 50 to 100% for dicamba‐OCl complexes. Maximum concentrations in the leaching profiles of the herbicide‐OCl complexes were much smaller than for the technical compounds. Bioassays of dicamba‐OCl complexes as preemergence herbicide showed the same efficiency as the technical compound. These results suggest OCls as possible carriers in controlled release formulations for very mobile and persistent acidic herbicides, thereby decreasing their potential for surface and ground water contamination.
Low Frequency Impedance Behavior of Montmorillonite Suspensions
Authors: Dudley Lynn M. , Bialkowski Stephen , Or Dani , Junkermeier Chad
Published: February 2014

Large changes in permittivity have been observed as the frequency of an electromagnetic (EM) field applied to systems containing phases of contrasting permittivity is changed. Two mechanisms, polarization of a diffuse double layer (DDL) and polarization of the charge imbalance created by contact of two phases of different permittivity (the Maxwell‐Wagner [MW] effect), are responsible for the frequency dependence of dielectric properties. To use the frequency dependence of dielectric properties to determine soil geometrical and electrochemical properties, the two mechanisms must be quantified. Three models of the frequency dependent dielectric properties, based on terms representing polarization of the electrical double layer that develops at the electrode surface, polarization of the DDL and the MW effect, were used to investigate the dielectric spectrum of montmorillonite suspensions. Dielectric spectra of suspensions of three particle‐size separates (r > 1.0 μm, 1.0 μm > r > 0.2 μm, 0.2 μm > r) of homoionic (Na+ or Ca2+) were measured at a suspension density of 5.0 g of clay in 50 mL of water. Impedance plane plots suggested the contribution of three relaxation processes to the spectra. While all three models reproduced the data, they gave different interpretations of the data. Two models attributed relaxation in the kHz range to electrode polarization, relaxation at approximately 10 kHz to DDL polarization and relaxation at 1 MHz to MW polarization. The third model assigned MW polarization to the relaxation at 10 kHz and DDL polarization to the relaxation at 1 MHz.
Biomass Distribution and Nitrogen‐15 Partitioning in Citrus Trees on a Sandy Entisol
Authors: Mattos Dirceu , Graetz Donald A. , Alva Ashok K.
Published: February 2014

The area under citrus production in Florida is 332 000 ha, with a production of 10 to 12 million metric tonnes of fruit annually. Nutrient management recommendations are needed to increase N uptake efficiency and to minimize nitrate leaching below the root zone. The objectives of this study were (i) to evaluate biomass distribution of 6‐yr‐old ‘Hamlin’ orange trees [Citrus sinensis (L.) Osbeck] on ‘Swingle citrumelo’ [Poncirus trifoliata (L.) Raf. × C. × paradisi Macfad.] rootstock grown in a sandy soil under low volume irrigation, and (ii) to estimate partitioning of 15N fertilizer applied to the soil during early spring into different tree components. We evaluated biomass of tree components (leaves, twigs, trunk, taproot, roots, and fruit), and N recovery and distribution of 15NH415NO3 (AN) and 15N‐urea (UR) (10 atom % 15N) applied to the soil surface. About 70% of dry matter biomass of trees was aboveground (AG). Length density of feeder roots was concentrated at a depth of 0 to 15 cm below the soil surface and varied from 1.87 to 0.88 cm cm−3 at 0.5‐ and 1.5‐m distance from the trunk, respectively. Total recoveries of 15N by trees were 25.5% for UR and 39.5% for AN at fruit harvest, 280 d after fertilization. Mean accumulation of applied 15N in recent leaf flush was 4.2% and that of older leaves was 2.5%. Accumulation of 15N was low in woody tissue. Since fruit represented a large sink for N (10.2 and 18.4% recovery of 15N applied as UR and AN, respectively), we confirmed the importance of N fertilization before fruit development.
Mineral Transformations in Permafrost‐Affected Soils, North Kolyma Lowland, Russia
Authors: Alekseev A. , Alekseeva T. , Ostroumov V. , Siegert C. , Gradusov B.
Published: February 2014

Soils in permafrost sediments were studied on the Kolyma Lowland, North‐East Siberia. Mineral transformations were studied by comparing samples from different geochemical positions relative to the permafrost table. The profiles studied are developed from Yedoma deposits (mid to late Pleistocene). Mineralogical composition of study soils is controlled by the illite‐chlorite mineralogy of the parent Yedoma deposits, climatic conditions (extremely cold and dry) and the effect of permafrost. Degradation of illite, weathering of Fe‐containing minerals (chlorite) with further Fe migration within the active layer and its crystallization at the cryogenic barrier in the form of lepidocrocite are the main processes of mineral transformations in the Kriozems studied. The highest concentration of lepidocrocite is associated with the boundary of permanently frozen ground. Geochemical processes are strongly influenced by the permafrost table. The boundary between the seasonally thawing soil and the permanently frozen ground is an important geochemical barrier.
Considerations for Improving the Accuracy of Permittivity Measurement using Time Domain Reflectometry
Authors: Robinson D. A. , Schaap M. , Jones S. B. , Friedman S. P. , Gardner C. M. K.
Published: February 2014

In a paper presented by Heimovaara (1993) a method of calibrating TDR sensors was presented using air and water. Time has moved on but time domain reflectometry (TDR) sensors are still calibrated in a number of different ways. In this article we present a rigorous investigation of the method proposed by Heimovaara and demonstrate its accuracy. We demonstrate that the placement of a starting point in any place other than the one determined using Heimovaara's method results in erroneous permittivity measurement. This will be most significant at low values of permittivity. We propose that Heimovaara's method be adopted as a standard method for calibrating TDR sensors for measuring permittivity. The discussion centers on the placement of the first time marker used to measure the signal travel time from which permittivity is measured. Our modeling results suggest that this point is slightly forward of the apex of the bump on the waveform which corresponds to the impedance increase as the wave travels from the cable into the TDR sensor head. We also demonstrate that using the apex of this bump as a starting point reference can lead to erroneous measurements of travel time in layered dielectric media. Finally we examine the use of long cables to connect sensors to the TDR. We demonstrate that the travel time in the cable changes as a function of temperature and that fixed travel time markers based on cable length cause error in the measurement of travel time. For a 2.6‐m cable the error was 1.6% at 50°C, and 4.7% for a 10.3‐m cable, relative to calibration at 25°C. Software that tracks the sensor head either through the impedance mismatch caused by the head or using an electrical marker eliminates this source of error.
Long‐Term Evaluations of Seasonally Saturated “Wetlands” in Western Kentucky
Authors: Karathanasis A. D. , Thompson Y. L. , Barton C. D.
Published: February 2014

A research program was initiated in 1993 to monitor water‐table depth, redox potential, and soil matric potential at four sites. The selected sites were woodlands with water tables present at or near the soil surface during late winter and spring. Soil morphology was described and permanent monitoring instruments were installed on eight soils. Hydrosequences of three soils, which represented an Endoaquept‐Fragiaqualf‐Fraglossudalf and a Fraguaqualf‐Fraglossudalf‐Fraglossudalf sequences, were studied at two sites. An Epiaqualf and a Fragiaqualf were monitored at each of the remaining sites. Six of the eight soils experienced wetland hydrology in most years, while the other two exhibited sporadic saturation events above 25 cm. Saturated conditions occurred mainly in late winter and spring, with longest duration in the lowest landscape positions. On the wettest soils, redox levels <200 mV developed during late winter and continued into the growing season. Of the six soils meeting the hydrology criterion only three experienced both, functional hydric soil conditions (<200 mV redox potential) and exhibited definitive hydric soil indicators. However, hydric soil indicators were also present in two of the three other soils that developed only moderately reduced conditions (<350 mV). In contrast, only one of the six soils with wetland hydrology did not meet the hydrophytic vegetation criterion, while one nonhydric soil met the criterion. The presence, depth, and quality of fragipans appeared to influence the expression of hydric conditions through episaturation, endosaturation, and amphisaturation processes, creating a range of aquic and oxyaquic conditions. These findings emphasize the complexity of seasonally saturated wetland ecosystems and the difficulties in assessing and implementing wetland identification and delineation criteria.
Fluorescence characteristics of natural organic matter in water under sequential exposure to UV irradiation/chlor(am)ination
Authors: Guo Qianjun , Zhang Zaili , Ma Zhengbo , Liang Yongmei , Liu Wei
Published: February 2014

The organic matter in International Humic Substances Society Natural Organic Matter (IHSS NOM) water exposed to ultraviolet (UV) irradiation and chlor(am)ine sequentially under practically relevant conditions was characterized based on fluorescence spectra. IHSS NOM water exposed to UV irradiation or chlor(am)ine alone was also evaluated. Both chlor(am)ine alone and UV/chlor(am)ine exposure showed similar chlor(am)ine demand and fluorescence spectra. UV irradiation and UV/chlorine exposure diminished the fluorescence intensity of IHSS NOM water, while UV/chloramine exposure resulted in increased fluorescence intensity. When compared with the results obtained following chlor(am)ination alone, IHSS NOM water showed decreased chlorine decay and increased chloramine decay after UV irradiation/chlor(am)ination. Additionally, IHSS NOM water exposed to UV/chloramine and chloramine showed less disinfection by-product (DBP) formation than water subjected to UV/chlorine and chlorine. Overall, these findings indicate that UV irradiation degrades NOM molecules to low-molecular-weight fractions, facilitating the subsequent reaction with chlor-(am)ine. However, chlorine and chloramine play different roles in the reaction. Chlorine degradation and substitution dominates the process of UV/chlorine exposure, while chloramine substitution is the major reaction during UV/chloramine exposure.