bluuebunny/crossref_metadata_2025 huggingface dataset:
Antimicrobial resistance and detection of mecA and blaZ genes in coagulase-negative Staphylococcus isolated from bovine mastitis
Authors: Soares Lidiane C. , Pereira Ingrid A. , Pribul Bruno R. , Oliva Marcelo S. , Coelho Shana M.O. , Souza Miliane M.S.
Published: September 2012

The present study evaluated the pheno- and genotypical antimicrobial resistance profile of coagulase-negative Staphylococcus (CNS) species isolated from dairy cows milk, specially concerning to oxacillin. Of 100 CNS isolates, the S. xylosus was the prevalent species, followed by S. cohnii, S. hominis, S. capitis and S. haemolyticus. Only 6% were phenotypically susceptible to the antimicrobial agents tested in disk diffusion assay. Penicillin and ampicillin resistance rates were significantly higher than others antimicrobials. Four isolates were positive to mecA gene (4%), all represented by the S. xylosus species. The blaZ gene was detected in 16% of the isolates (16/100). It was noticed that all mecA + were also positive to this gene and the presence of both genes was correlated to phenotypic beta-lactamic resistance. We conclude that CNS species from bovine milk presented significantly distinct antimicrobial resistance profiles, evaluated by phenotypic and genotypic tests, which has implications for treatment and management decisions.
Serologic and molecular diagnostic and bioassay in mice for detection of Toxoplasma gondii in free ranges chickens from Pantanal of Mato Grosso do Sul
Authors: Holsback Luciane , Pena Hilda F. de J. , Ragozo Alessandra , Lopes Estela G. , Gennari Solange M. , Soares Rodrigo M.
Published: September 2012

The aim of this study was to investigate the occurrence of Toxoplasma gondii and compare the results obtained in the Modified Agglutination Test (MAT), Polimerase Chain Reaction (PCR) and bioassay in mice. In order to accomplish this, 40 free-range chickens from eight farms in neighboring areas to the Pantanal in Nhecolândia, Mato Grosso do Sul, were euthanized and blood samples, brain and heart were collected. The occurrence of anti-T. gondii antibodies found in chickens was 67.5% (27 samples), considering as a cutoff point the dilution 1:5. Among the samples analyzed, 7 (25.9%) were positive in the dilution 1:5, 3 (11.1%) in 1:10, 2 (7.4%) in 1:20, 3 (11.1%) in 1:320, 1 ( 3.7%) in 1:640, 3 (11.1%) in 1:1280, 2 (7.4%) in 1:2560, 4 (14.8%) in 1:5120 and 2 (7.4%) in 1:10.240. From the mixture of tissue samples (brain and heart) from the chickens analyzed, 16 (40%) presented electrophoretic bands compatible with T. gondii by PCR (gene B1). In the comparison of techniques, 59.26% positivity in PCR was revealed among animals that were seropositive in MAT (cutoff 1:5). From 141 inoculated mice, six (4.44%) died of acute toxoplasmosis between 15 and 23 days after inoculation. Surviving mice were sacrificed at 74 days after inoculation, and a total of 28 cysts were found in the brains of 10 distinct groups. From the seropositive hens, 27 bioassays were performed and 11 (40.7%) isolates were obtained. A greater number of isolations happened in mice that were inoculated with tissues from chickens that had high titers for anti-T. gondii antibodies. Chronic infection in mice was observed in nine groups (33.3%) from five different properties. Among the surviving mice, 25.6% were positive for T. gondii in MAT (1:25). From mice positive in PCR, 87.5% were also positive in MAT. Among the PCR-negative mice, 5.2% were positive for T. gondii in MAT. It can be concluded through this study that the occurrence of infecton by T. gondii in the rural properties studied was high, that PCR directed to gene B1 does not confirm the viability of the parasite, but it can be used as a screening method for the selection of chickens infected by T. gondii, that the animals with titer greater than 10 must be prioritized for the selection of animals for bioassay, since for them, the chances of isolating the parasite are greater and that seroconversion in experimentally infected mice is not a good indicator for isolating the agent.
Moraxella bovoculi em casos de ceratoconjuntivite infecciosa bovina no Rio Grande do Sul
Authors: Libardoni Felipe , Scherer Charles F.C. , Farias Luana , Vielmo Andréia , Balzan Claudia , Vargas Agueda C. de
Published: September 2012

A ceratoconjuntivite infecciosa (CI), embora raramente fatal, resulta em perdas econômicas significativas para os rebanhos bovinos e ovinos. Os principais agentes causadores dessa enfermidade são Moraxella bovis e Moraxella ovis. Em 2007 foi descrita uma nova espécie também responsável pela CI e denominada Moraxella bovoculi, que até o presente momento, não havia sido relatada no Brasil. Assim, objetivou-se com este trabalho caracterizar e distinguir 54 isolados de Moraxella spp. de amostras clínicas oriundas de 34 bovinos e 17 ovinos, encaminhadas ao Laboratório de Bacteriologia da Universidade Federal de Santa Maria no período de 1990 a 2011, visando a identificação de M. bovoculi. A distinção dos isolados foi fundamentada nas características genotípicas, pela amplificação parcial da região intergênica 16S-23S e clivagem dos produtos da amplificação com enzima RsaI. Como resultados, 25 (46%) isolados foram caracterizados como M. bovis, 17 (32%) como M. ovis e 12 (22%) como M. bovoculi. Logo, conclui-se que M. bovoculi encontra-se presente no rebanho bovino do Rio Grande do Sul e, portanto, no Brasil.
Antimicrobial resistance of Staphylococcus spp. from small ruminant mastitis in Brazil
Authors: França Chirles A. , Peixoto Rodolfo M. , Cavalcante Marielly B. , Melo Natoniel F. , Oliveira Celso José B. , Veschi Josir Laine A. , Mota Rinaldo A. , Costa Mateus M.
Published: September 2012

The study aimed to determine the antimicrobial resistance patterns and to identify molecular resistance markers in Staphylococcus spp. (n=210) isolated from small ruminant mastitis in Brazil. The antimicrobial resistance patterns were evaluated by the disk diffusion test and by detection of the presence of mecA, blaZ, ermA, ermB, ermC and msrA genes by PCR. The efflux pump test was performed using ethidium bromide and biofilm production was determined by Congo red agar test along with PCR for detection of the icaD gene. The isolates were most resistant to amoxicillin (50.0%), streptomycin (42.8%), tetracycline (40.4%), lincomycin (39.0%) and erythromycin (33.8%). Pan-susceptibility to all tested drugs was observed in 71 (33.8%) isolates and 41 Staphylococcus isolates were positive for the efflux pump. Although phenotypic resistance to oxacillin was observed in 12.8% of the isolates, none harbored the mecA gene. However, 45.7% of the isolates harbored blaZ indicating that beta-lactamase production was the main mechanism associated with staphylococci resistance to beta-lactams in the present study. The other determinants of resistance to antimicrobial agents ermA, ermB, ermC, and msrA were observed in 1.4%, 10.4%, 16.2%, and 0.9% of the isolates, respectively. In addition, the icaD gen was detected in 32.9% of the isolates. Seventy three isolates (54 from goats and 19 from sheep) were negative for all resistance genes tested and 69 isolates presented two or more resistance genes. Association among blaZ, ermA, ermB, ermC and efflux pump were observed in 17 isolates, 14 of which originated from goats and three from sheep. The data obtained in this study show the resistance of the isolates to beta-lactamics, which may be associated with the use of antimicrobial drugs without veterinary control.
Lesões do sistema urinário em 1.063 cães
Authors: Inkelmann Maria Andréia , Kommers Glaucia D. , Trost Maria Elisa , Barros Claudio S.L. , Fighera Rafael A. , Irigoyen Luiz Francisco , Silveira Isadora P.
Published: September 2012

Com o objetivo de realizar um estudo abrangente das lesões do sistema urinário em cães e determinar a sua prevalência, epidemiologia, importância clínica e possíveis causas associadas, foram revisados os protocolos de necropsias de cães realizadas no período de janeiro de 1999 a dezembro de 2010 no LPV-UFSM. Nesse período foram necropsiados 3.189 cães e destes, cerca de 30% apresentaram lesões no sistema urinário. Na maioria dos cães (79,1%) foram observadas lesões únicas e em aproximadamente 21% havia lesões múltiplas no sistema urinário, totalizando 1.373 lesões. Destas, 1.014 (73,8%) foram observadas no rim. No trato urinário inferior (TUI) foram diagnosticadas 359 (26,2%) lesões. Um terço das lesões no sistema urinário dos cães necropsiados foram causa de morte espontânea ou razão para eutanásia (ME/EUT). As demais foram consideradas como achados incidentais. As principais lesões renais diagnosticadas, em ordem decrescente de prevalência, foram: nefrite túbulo-intersticial, infarto, nefrite granulomatosa (parasitária), glomerulonefrite, neoplasmas metastáticos/multicêntricos, pielonefrite/ pielite e hidronefrose. As principais lesões do TUI diagnosticadas, em ordem decrescente de prevalência, foram: cistite, presença de inclusões virais (morbilivírus), urolitíase, dilatação da bexiga, ruptura de bexiga (com uroperitônio) e neoplasmas metastáticos/multicêntricos. As características epidemiológicas como sexo, raça e idade dos cães afetados tiveram variações expressivas de acordo com o tipo de lesão diagnosticada. Uremia foi observada em um número significativo de casos de ME/EUT e foi principalmente secundária a lesões renais.
Histomorphological and immunohistochemical characterization of 172 cutaneous round cell tumours in dogs
Authors: Araújo Marina Rios , Preis Ingred Sales , Lavalle Gleidice Eunice , Cassali Geovanni Dantas , Ecco Roselene
Published: September 2012

This paper describes the use of a panel of antibodies (CD117, CD3, CD79a, CD45, cytokeratin, vimentin and E-cadherin) on formalin-fixed, paraffin-embedded sections of canine cutaneous round cell tumours. Neoplastic tumours were diagnosed by histology and histochemical stains and included 107 mast cell tumours, 31 cutaneous histiocytomas, two localized histiocytic sarcomas, 21 cutaneous lymphomas, three plasma cell tumours, one transmissible venereal tumour and seven unclassified round cell tumours. The histologic diagnosis was modified in 39.5% of the total 172 neoplasms. The staining for CD45 and Ecadherin were variable, and therefore, the final diagnoses of cutaneous histiocytoma and localized histiocytic sarcoma were made based on histology in association with negative results for CD3, CD79a, CD117 and cytokeratin. The cellular origin of unclassified round cell tumours was defined in all cases. Cutaneous B-cell lymphoma and plasma cell tumours were CD79a-positive and could be distinguished from each other by the morphological characteristics. Mast cell tumours and T cell lymphoma were CD117 and CD3 positive, respectively. The positive staining for vimentin and the negative staining for CD3, CD79a, CD117 and cytokeratin favoured the diagnosis of transmissible venereal tumours. Thus, the final diagnosis of cutaneous round cell tumours should be based on the interpretation of immunohistochemical results together with the cellular morphology observed by histology. Therefore, more studies to optimize the specific markers in formalin-fixed, paraffinembedded tissues (especially for histiocytes) are required for definitive diagnosis of round cell tumours in dogs.
Ocorrência de Dioctophyma renale em Galictis cuja
Authors: Zabott Marivone V. , Pinto Simone B. , Viott Aline M. , Tostes Raimundo A. , Bittencourt Laura H.F.B. , Konell Aline L. , Gruchouskei Leonardo
Published: September 2012

A dioctofimose é uma parasitose causada pelo Dioctophyma renale (Goeze, 1782) de ocorrência mundial e acomete animais domésticos e silvestres. Em março de 2010, um exemplar adulto (macho) de Galictis cuja (Molina, 1782), encontrado morto por atropelamento no município de Guaíra, Paraná foi encaminhado ao laboratório de Patologia Veterinária de Universidade Federal do Paraná (UFPR), Campus Palotina, para a realização da necropsia. O cadáver apresentava bom estado nutricional e autólise moderada. Foram observados três exemplares de parasitos na cavidade abdominal, mas os rins encontravam-se preservados. Os parasitos foram fixados em formol acético e encaminhados ao laboratório de Parasitologia Veterinária da UFPR para identificação. Os exemplares coletados foram identificados como Dioctophyma renale, sendo duas fêmeas, uma com 39cm de comprimento por 4mm de largura e a outra com 16cm de comprimento por 4mm de largura e, um macho com 16cm de comprimento por 3mm de largura. O presente trabalho relata a ocorrência de parasitismo por D. renale em G. cuja na região oeste do estado do Paraná.
Mortalidade por acidentes de transporte terrestre no Brasil na última década: tendência e aglomerados de risco
Authors: Morais Neto Otaliba Libânio de , Montenegro Marli de Mesquita Silva , Monteiro Rosane Aparecida , Siqueira Júnior João Bosco , Silva Marta Maria Alves da , Lima Cheila Marina de , Miranda Luiz Otávio Maciel , Malta Deborah Carvalho , Silva Junior Jarbas Barbosa da
Published: September 2012

OBJETIVO: Analisar a tendência temporal da mortalidade por Acidentes de Transporte Terrestre (ATT) e identificar a existência e a localização de aglomerados de alto risco de mortes por ATT. METODOLOGIA: Estudo descritivo de tendência da mortalidade por ATT, pedestre, ocupante de motocicleta e de veículo, de 2000 a 2010 e análise espacial para 2000 e 2010. Os dados foram obtidos do Sistema de Informações sobre Mortalidade; calcularam-se as taxas padronizadas por idade, para Unidades Federadas (UF) e municípios por porte populacional. RESULTADOS: A taxa de mortalidade por ATT entre 2000 e 2010 variou de 18 para 22,5 óbitos/100 mil habitantes. O risco de morte para pedestre reduziu, os de ocupantes de veículos e de motocicletas apresentaram crescimento. O maior risco de morte por ATT ocorreu nos municípios com até 20 mil habitantes e nos de 20 a 100 mil. A análise espacial mostrou os aglomerados de risco para ATT e para ocupantes de motocicletas com aumento destes entre 2000 e 2010 e ampliação das áreas com maior risco na região Nordeste. CONCLUSÃO: Aumento das taxas de mortalidade por ATT principalmente na região Nordeste. Faz-se necessário uma atuação coordenada do governo, da sociedade civil e dos próprios cidadãos no enfretamento desta realidade.
Constituição de sujeitos na gestão em saúde: avanços e desafios da experiência de Fortaleza (CE)
Authors: Araújo Carmem Emmanuely Leitão , Pontes Ricardo José Soares
Published: September 2012

Trata-se de uma pesquisa sobre possibilidades e limites da constituição de sujeitos na gestão em saúde, a partir da experiência de Fortaleza no período de 2005 a 2008. Aborda-se o sujeito a partir de um referencial histórico-cultural, o qual considera a interação dialética entre o individual e o coletivo no aprofundamento da consciência humana sobre si e o mundo. Foram realizados grupos focais com gestores vinculados à Atenção Primária à Saúde e utilizados dados secundários. Por meio de uma abordagem hermenêutica dialética procurou-se compreender o sentido das narrativas construídas. Identificaram-se categorias empíricas que foram analisadas: cointencionalidade de mudança, direcionalidade política e conceitual, gestão humana, diminuição da hierarquia, fragmentação do processo de trabalho, concentração do poder de decisão. Sobressaíram-se reflexões sobre três políticas estratégicas: cogestão, humanização e educação permanente em saúde. Concluiu-se que, apesar da persistência de obstáculos, para a melhoria da qualidade dos sistemas e serviços de saúde é imprescindível instituir uma gestão democrática por meio de arranjos organizacionais e métodos participativos que potencializem a inserção e o comprometimento dos atores do Sistema Único de Saúde (SUS).
Pacientes em centro de referência para Hanseníase: Rio de Janeiro e Duque de Caxias, 1986-2008
Authors: Hacker Mariana de Andrea Vilas Boas , Sales Anna Maria , Albuquerque Edson Cláudio Araripe , Rangel Emanuel , Nery Jose Augusto Costa , Duppre Nadia Cristina , Sarno Euzenir Nunes
Published: September 2012

O objetivo deste trabalho foi comparar dados epidemiológicos de pacientes de hanseníase residentes em dois municípios com perfil socioeconômico e nível de endemicidade diferentes e que foram acompanhados em um mesmo centro de referência. Foi realizado um estudo descritivo dos dados de pacientes tratados no ambulatório Souza Araújo, 1986 a 2008, residentes nos municípios do Rio de Janeiro (n = 1353) e Duque de Caxias (n = 336). Entre os pacientes desta cidade, em comparação com os da outra, observou-se maior proporção de casos: com idade inferior a 15 anos, multibalicares, com maior índice baciloscópico (IB) inicial, e detectados através da vigilância de contatos. Os pacientes de Duque de Caxias apresentaram menor renda média e nível de escolaridade. Não foram observadas diferenças estatisticamente significativas quanto ao sexo, grau de incapacidade inicial, reação no diagnóstico, IB final, abandono e regularidade do tratamento. As diferenças encontradas entre os pacientes acompanhados em um mesmo centro de referência poderiam estar, em parte, relacionadas a diferenças contextuais existentes entre os municípios. Por outro lado, observou-se que a oferta de tratamento e acompanhamento podem minimizar o efeito que os fatores contextuais apresentam sobre os desfechos de saúde.
Biofuel plant species and the contribution of genetic improvement
Authors: Dias Luiz Antônio dos Santos
Published: September 2012

The paper analyses the puzzle of the food-energy-environmental security interaction, to which biofuels are part of the solution. It presents and discusses the contribution of genetic improvement to biofuels, with regard to the production of raw materials (oil and ethanol-producing plant species) and designs perspectives, opportunities, risks and challenges, with a special focus on the Brazilian scene. Bioethanol is a consolidated biofuel owing largely to the sugarcane breeding programs. These programs released 111 sugarcane cultivars and were responsible for a 20.8 % gain in productivity of bioethanol (in m³ ha-1) between 2000 and 2009. The program of Brazilian biodiesel production, initiated in 2005, had an annual growth rate of 10 % and the country is already the world's fourth largest producer. However, the contribution of breeding to biodiesel production is still modest, due to the lack of specific improvement programs for oil.
Program R: applications in plant breeding
Authors: Peternelli Luiz Alexandre
Published: September 2012

Nowadays the demand for so-called free, or open source software for data analysis as well as the appeal to use it is great. An public domain software that has become extremely well-known, with ever-increasing numbers of fans and even co-workers, is Environment R, or simply R. R is extremely useful for data analysis and manipulation in view of a range of tools already implemented. Also, R is not simply a statistical program, because, by its easy on using internal functions and also creating new ones, statistical procedures applied to data can also be created, manipulated, evaluated and interpreted. R contains numerous libraries (or packages), some already included in the default setting. This course will focus on the application of R in statistical analyses in plant breeding. Explanations on the use of various commands and functions will be illustrated with examples, to facilitate the interpretation and adaptation to other similar problems.
Accessibility and exchange of plant germplasm by Embrapa
Authors: Bustamante Patrícia Goulart , Ferreira Francisco Ricardo
Published: September 2012

This paper presents information about the organizational structure of Embrapa's banks and collections of plant germplasm and lists the 14 projects that comprise the Plant Genetic Resources Network which houses about 200 000 access and correspond to a collection of 300 genera, 787 species (90 % exotic). The main goal of the Plant Genetic Resources Network is being a source of variability for breeders of nationally and internationally research institutions. The paper also presents the different ways of knowing and accessing the collection of plant genetic resources maintained at Embrapa. Special emphasis is given to the way of the researchers can import and export plant germplasm, including presentation of a series of accessions exchanged in the last 35 years by Embrapa Genetic Resources and Biotechnology. The paper also provides the necessary documents and specifies the step-by-step to exchange and quarantine of germplasm held by Embrapa Genetic Resources and Biotechnology.
Crizotinib for the Treatment of ALK-Rearranged Non-Small Cell Lung Cancer: A Success Story to Usher in the Second Decade of Molecular Targeted Therapy in Oncology
Authors: Ou Sai-Hong Ignatius , Bartlett Cynthia Huang , Mino-Kenudson Mari , Cui Jean , Iafrate A. John
Published: September 2012

Crizotinib, an ALK/MET/ROS1 inhibitor, was approved by the U.S. Food and Drug Administration for the treatment of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) in August 2011, merely 4 years after the first publication of ALK-rearranged NSCLC. The crizotinib approval was accompanied by the simultaneous approval of an ALK companion diagnostic fluorescent in situ hybridization assay for the detection of ALK-rearranged NSCLC. Crizotinib continued to be developed as an ALK and MET inhibitor in other tumor types driven by alteration in ALK and MET. Crizotinib has recently been shown to be an effective ROS1 inhibitor in ROS1-rearranged NSCLC, with potential future clinical applications in ROS1-rearranged tumors. Here we summarize the heterogeneity within the ALK- and ROS1-rearranged molecular subtypes of NSCLC. We review the past and future clinical development of crizotinib for ALK-rearranged NSCLC and the diagnostic assays to detect ALK-rearranged NSCLC. We highlight how the success of crizotinib has changed the paradigm of future drug development for targeted therapies by targeting a molecular-defined subtype of NSCLC despite its rarity and affected the practice of personalized medicine in oncology, emphasizing close collaboration between clinical oncologists, pathologists, and translational scientists.
Pile heat exchangers: thermal behaviour and interactions
Authors: Loveridge Fleur , Powrie William
Published: September 2012

Thermal piles – that is structural foundation piles also used as heat exchangers as part of a ground energy system – are increasingly being adopted for their contribution to more sustainable energy strategies for new buildings. Despite over a quarter of a century having passed since the installation of the first thermal piles in northern Europe, uncertainties regarding their behaviour remain. This paper identifies the key factors which influence the heat transfer and thermal–mechanical interactions of such piles. In terms of heat output, pile aspect ratio is identified as an important parameter controlling the overall thermal performance. Temperature changes in the concrete and surrounding ground during thermal pile operation will lead to additional concrete stresses and displacements within the pile–soil system. Consequently designers must ensure that temperatures remain within acceptable limits, while the pile geotechnical analysis should demonstrate that any adverse thermal stresses are within design safety factors and that any additional displacements do not affect the serviceability of the structure.
A review of stopping sight distance in road design guidelines
Authors: Roussiamanis Nikolaos , Kaltsounis Antonis , Vardaki Sophia , Kanellaidis George
Published: September 2012

A fundamental principle of international road geometric design guidelines and handbooks is that along a roadway, the available sight distance should be sufficient to enable a driver, travelling at a reasonable speed, to stop before reaching a stationary object on his path. It is generally recognised that this required stopping sight distance depends on human, vehicle, highway and environmental factors and its estimation is a complicated issue. Therefore, in most road geometric design guidelines worldwide, the mathematical models used for estimation of the required stopping sight distance have been revised several times. The objective of this paper is to review, analyse and compare the changes that have occurred over the years in the models used for estimating required stopping sight distance in German, American and Australian guidelines for the geometric design of rural roads, and to examine relevant human factor aspects that have not yet been sufficiently incorporated into design guidelines.
Canopy Cover and Leaf Area Index Relationships for Wheat, Triticale, and Corn
Authors: Nielsen David C. , Miceli‐Garcia Juan J. , Lyon Drew J.
Published: September 2012

Previously collected data sets that would be useful for calibrating and validating AquaCrop contain only leaf area index (LAI) data but could be used if relationships were available relating LAI to canopy cover (CC). The objective of this experiment was to determine relationships between LAI and CC for corn (Zea mays L.), winter wheat (Triticum aestivum L.), and spring triticale (×Triticosecale spp.) grown under dryland or very limited irrigation conditions. The LAI and CC data were collected during 2010 and 2011 at Akron, CO, and Sidney, NE, using a plant canopy analyzer and point analysis of above‐canopy digital photographs. Strong relationships were found between LAI and CC that followed the exponential rise to a maximum form. The relationship for corn was similar to a previously published relationship for LAI <2 m2 m−2 but predicted lower CC for greater LAI. Relationships for wheat and triticale were similar to each other.
Nitrogen Source Effects on Ammonia Volatilization as Measured with Semi‐Static Chambers
Authors: Jantalia Claudia Pozzi , Halvorson Ardell D. , Follett Ronald F. , Rodrigues Alves Bruno Jose , Polidoro Jose Carlos , Urquiaga Segundo
Published: September 2012

Ammonia (NH3) volatilization is one of the main pathways of N loss from agricultural cropping systems. This study evaluated the NH3–N loss from four urea‐based N sources (urea, urea–ammonium nitrate [UAN], SuperU, and ESN [polymer‐coated urea]) surface band applied at a rate of 200 kg N ha−1 to irrigated, strip‐till corn production systems for 2 yr using semi‐static chambers (semi‐open and open) to measure NH3–N loss. The efficiency of the semi‐static chambers in estimating NH3–N loss under field conditions was determined using 15N labeled urea applied at rates of 50, 100, and 200 kg N ha−1. Both chamber types had similar NH3–N recoveries and calibration factors. Immediate irrigation with 16 to 19 mm of water 1 d after N fertilization probably limited NH3–N volatilization from surface‐applied N fertilizers to a range of 0.1 to 4.0% of total N applied. SuperU, which contains a urease inhibitor, had the lowest level of NH3–N loss when compared to the other N sources. Analyzed across years, estimated NH3–N losses for the N sources were in the order: ESN = UAN > urea > SuperU. Both years the results showed that measurement time may need to be increased to evaluate NH3–N volatilization from polymer‐coated urea N sources such as ESN. The open‐chamber method was a viable, low cost method for estimating NH3–N loss from small field plot N studies.
Winter Wheat Crop Reflectance and Nitrogen Sufficiency Index Values are Influenced by Nitrogen and Water Stress
Authors: Clay David E. , Kharel Tulsi Prasad , Reese Cheryl , Beck Dwayne , Carlson C. Gregg , Clay Sharon A. , Reicks Graig
Published: September 2012

In‐season N applications to winter wheat (Triticum aestivum L.) may increase profits and improve N fertilizer accuracy. The objectives of this experiment were to determine the impact of N and water stress on crop reflectance and N sufficiency index (SI) values. The experiment contained five N rates, two water treatments, and four blocks. Crop reflectance was measured at the stem extension and flag leaf growth stages, sufficiency index (SI)‐NDVIwf was ratio between the underfertilized normalized difference vegetation index value {NDVI = [near infrared (NIR)‐red]/[NIR+red]} and the NDVI value from well fertilized and well watered treatments, while SI‐NDVImz was ratio between underfertilized NDVI values and NDVI values from well fertilized plots within a water stress treatment. Yield losses due to water and N stress were determined using 13C isotopic discrimination. This research shows that: (i) at the stem extension and flag leaf growth stages, water stress and N stress increased, green, red, and red‐edge reflectance and reduced NDVI values (ii) following the economic optimum nitrogen rate (EONR) produced grain with greater than 120 g kg−1 protein and <10 min stability; (iii) at stem elongation and flag leaf, N fertilizer induced yield gains had a stronger relationship with SI‐NDVImz (stem extension, r = 0.49*; flag leaf, r = 0.51**) than SI‐NDVIwf (stem extension, r = 0.29; flag leaf, r = 0.33); and (iv) SI‐NDVImz had greater fertilizer recommendation accuracy than SI‐NDVIwf. These findings suggest that in wheat production, SI should be referenced to well fertilized areas within a management zone.
Change in Nitrogen Requirement with Increasing Grain Yield for Winter Wheat
Authors: Yue Shanchao , Meng Qingfeng , Zhao Rongfang , Ye Youliang , Zhang Fusuo , Cui Zhenling , Chen Xinping
Published: September 2012

Overestimates of N requirements have led to excessive N application and serious environmental pollution in intensively managed agricultural systems. A database comprising 1395 measurements was developed from 2000 to 2011 using 88 on‐farm and station experiments conducted in five key winter wheat (Triticum aestivum L.) domains in northern China. The database was created to evaluate the relationship between aboveground N uptake and grain yield with different N treatments and to quantify N requirements per Mg grain at different grain yield levels. Across all sites, wheat grain yield ranged from 1.6 to 11.8 Mg ha−1. The nitrogen requirement per megagram grain yield (Nreq.) increased with N supply from 20.8 kg under the treatment without N fertilizer to 25.7 kg under the excess N treatment. For the optimal N fertilizer treatment, the average Nreq. was 24.3 kg and it declined with increasing grain yield. For the yield ranges between <4.5 and 6.0 to 7.5 Mg ha−1, Nreq. decreased from 27.1 to 24.5 kg due to increasing harvest index (HI; from 0.39–0.46) and decreasing grain N concentration (from 2.41 to 2.21%). For the yield ranges between 6.0 to 7.5 and 9.0 to 10.5 Mg ha−1, Nreq. decreased from 24.5 to 22.7 kg due to decreasing grain N concentration (from 2.21 to 2.00%). For the yield ranges between 9.0 to 10.5 and >10.5 Mg ha−1, Nreq. changed little due to stability in grain N concentrations and HI. In conclusion, the N requirement of a crop was affected by both the amount of N supplied and the grain yield.
Bound Water Content of Air‐Dry Soils Measured by Thermal Analysis
Authors: Wang Yajing , Lu Sen , Ren Tusheng , Li Baoguo
Published: September 2012

Conventional oven‐drying method may not give accurate information of bound water content in soils. The objective of this study was to determine the fraction of soil water that is bound to soil colloids using the thermogravimetry (TG) technique. A heating program from room temperature (RT) to 200°C was developed to partition bound water into loosely bound water (equivalent to water content determined by conventional oven‐drying method) and tightly bound water that was not accounted by conventional oven‐drying method on original and organic matter (OM) removed soil samples. Nine air‐dry soils, with varying amounts of clay and OM contents, were tested. For the original air‐dry samples, bound water content ranged from 0.54 to 5.22%, and the fractions of loosely and tightly bound water were about 80 and 20%, respectively. On a mass fraction basis, the specific water adsorption capacity of soil OM was 10 to 40 times that of soil minerals. For most mineral soils, however, the contribution of soil minerals to bound water (>70%) was much larger than that of soil OM (<30%), since the mineral fraction usually dominates over the OM fraction. In a soil with high OM concentration but a relatively low clay content, OM contribution to bound water exceeded 50%. Soil specific surface area (SA) showed a strong influence on bound water content, and a linear relationship between SA and bound water content was established.
Rapid Automated Measurement System for Simultaneous Determination of Effective Air‐Filled Porosity and Soil Gas Diffusivity
Authors: Bonroy J. , Volckaert M. , Seuntjens P.
Published: September 2012

The effective air‐filled porosity and the gas diffusion coefficient are important soil parameters determining the success of soil bioremediation projects such as (bio)venting and (bio)sparging methods in combination with soil vapor extraction. We have developed a new method to sequentially measure the effective air‐filled porosity and the soil gas diffusion coefficient of a soil sample. During the purging of the sample, a fast and accurate measurement of the effective air‐filled porosity can be obtained. The subsequent diffusion measurement does not require a zero‐O2 concentration in the soil sample. The procedure further allows the calculation of the soil gas diffusion coefficient before an equilibrium O2 concentration has been reached. The results are obtained by combining the data of the inlet and outlet compartment in a single equation. A stable reading is reached when the results for the inlet and outlet compartment coincide with the results from the combined equation. The analysis time is reduced by 89 to 96% compared with methods that run until an equilibrium concentration has been reached. Moreover, combining data from inlet and outlet compartments increases the accuracy of the diffusivity measurement by a factor of two compared with previous methods.
The Fate of Glyphosate in Crop Residues
Authors: Rampoldi E. Ariel , Hang Susana , Barriuso Enrique
Published: September 2012

The environmental fate of glyphosate [N‐(phosphonomethyl)glycine] was studied in six crop residue (CR) types, three from maize (Zea mays L.) (M1, M2, and M3) and three from soybean [Glycine max (L.) Merr.] (S1, S2, and S3). Glyphosate adsorption was characterized through isotherms. The glyphosate distribution in CRs was characterized through the balance of 14C‐glyphosate radioactivity among the mineralized fraction, the extractable fractions (water and NH4OH), and the nonextractable fraction. Crop residues were characterized by elemental composition, organic C, total N, and biochemical parameters (soluble fraction, cellulose, hemicellulose, and lignin). Total microbial activity (TMA) was also assessed. Limited and reversible glyphosate adsorption on soybean and maize CRs was determined. The sorption coefficient Kf index range for maize CR was 1.5 to 8.3 L kg−1 and 2.6 to 7.4 L kg−1 for soybean CR. Organic C and hemicellulose partially explained adsorption variability. The addition of mineralized and nonextractable fractions of the initial 14C‐glyphosate applied on the CRs averaged 56%; however, differences were detected between soybean and maize CRs. Mineralization and nonextractable residues were 30.7 ± 11 and 32.5 ± 6% (soybean CR) and 44.3 ± 12 and 17 ± 7% (maize CR), respectively. We hypothesized that glyphosate molecules could be used initially by microorganisms as a labile C source. High variability in 14C‐glyphosate mineralization was observed in all crop residues, suggesting that the magnitude of the glyphosate mineralization process would be regulated by accessibility and the lability of other carbonate sources.
Performance of Three Identical Spectrometers in Retrieving Soil Reflectance under Laboratory Conditions
Authors: Pimstein Agustin , Notesco Gila , Ben-Dor Eyal
Published: September 2012

A wide range of electronic and mechanical noise factors can affect soil spectra when using different instruments or even when repeating a specific sample's measurements with the same spectrometer. In soil samples where very weak spectral features are monitored for chemometric purposes, alterations in wavelength location, peak absorption shape, or albedo intensity can limit the use of previously developed spectral models. To quantify this alteration and propose a standardization method, 12 soil samples and three different materials for internal standards (sand, glass and polyethylene) were analyzed. This population was concurrently measured with three identical spectrometers using a strict measurement protocol, and then by different operators with different protocols. Significant changes in the soil spectra were found when different operators performed the measurements, being reduced >50% when the strict protocol was applied. Sand was found to be the ideal internal standard for correcting the spectra to a reference spectrometer, even when different measuring protocols were used. This standardization also showed an improvement in the prediction of soil properties when applying chemometric spectral models even with different instruments, concluding that the use of an internal standard and a strict protocol must be applied for soil spectral measurements. As the measuring factors described in this research also affect any infrared diffuse reflectance spectroscopy measurements, the proposed method should be applicable to any instrumentation and configuration being used. This is crucial to enabling spectral comparisons between different spectrometers or, more importantly, to establishing robust chemometric models and to exchange soil spectral information.
Uncertainties in Plot‐Scale Mass Balance Measurements Using Aeolian Sediment Traps
Authors: Tidjani A. D. , Bielders C. L. , Rosillon D. , Ambouta K. J.-M.
Published: September 2012

Modified Wilson and Cooke (MWAC) sediment catchers are commonly used for quantifying aeolian sediment transport in the saltation layer. The accuracy of aeolian mass flux and mass balance estimates using MWAC catchers has, however, not been reported in detail so far. By combining analytical error propagation equations and Monte Carlo simulation, this study tested a random error propagation scheme that incorporates six sources of uncertainty: sediment mass, MWAC inlet diameter, vertical position of the catchers, trapping efficiency, horizontal spacing between catcher arrays, and wind direction. For a weighing uncertainty of 0.01 g, the relative uncertainty in the cumulative mass flux of sediment reached up to 140%, but this generally affected only the highest catchers. The relative error in the measured unit mass transport was much less, ranging between 2 and 20%, with an average of 10%. The relative uncertainty in the corrected cumulative unit sediment mass transport, however, was found to be 32%, on average, because of the high relative uncertainty in the trapping efficiency of 31%. The relative uncertainty in the plot‐scale mass balances ranged between 32 and 80%. Uncertainty in the trapping efficiency and the measured unit mass transport contributed most to the mass balance uncertainty, but the uncertainty in the wind direction sometimes also contributed substantially. The high uncertainties that potentially affect the sediment mass transport and mass balances highlight the need for their systematic reporting in future studies. We also investigated possible pathways for reducing the uncertainty.
Soil Aggregation and Associated Organic Carbon Fractions as Affected by Tillage in a Rice–Wheat Rotation in North India
Authors: Kumari Mamta , Chakraborty Debashis , Gathala Mahesh K. , Pathak H. , Dwivedi B.S. , Tomar Rakesh K. , Garg R.N. , Singh Ravender , Ladha Jagdish K.
Published: September 2012

Soil samples were obtained from a long‐term trial conducted on a silty loam at Sardar Vallabhbhai Patel University of Agriculture & Technology, Modipuram (Meerut), in 2007–2008 to study the effects of various combinations of conventional and zero‐tillage (ZT) and raised‐bed systems on soil aggregation and associated organic C fractions in the 0‐ to 5‐cm and 5‐ to 10‐cm depth in a rice–wheat (Orysa sativa L.–Triticum aestivum L.) rotation. Macroaggregates increased under a ZT rice (direct‐seeded or transplanted) and wheat rotation with the 2‐ to 4‐mm fraction greater than that of the 0.25‐ to 2‐mm fraction. Bulk and aggregate associated C increased in ZT systems with greater accumulation in macroaggregates. The fine (0.053–0.25 mm) intra‐aggregate particulate organic C (iPOM‐C), in 0.25‐ to 2‐mm aggregates, was also higher in ZT than conventional tillage. A higher amount of macroaggregates along with greater accumulation of particulate organic C indicates the potential of ZT for improving soil C over the long‐term in rice‐wheat rotation.
Soil Spatial Dependence in Three Arctic Ecosystems
Authors: Banerjee Samiran , Bedard-Haughn Angela , Si Bing C. , Siciliano Steven D.
Published: September 2012

We examined the spatial variability of 13 soil physicochemical attributes and their correlation with soil gravimetric moisture content (θg) in 279 soil samples collected from three high arctic ecosystems. The observed correlations between θg and pH, NH4, NO3, total organic C, dissolved organic C, and dissolved organic N contents in the Arctic are considerably higher than temperate agricultural and tropical grassland soils, which suggests that θg plays a critical role in arctic soil ecosystems. We found that, despite the climatic extremities, arctic soil attributes are spatially well structured and their spatial dependency is consistent within and between the studied ecosystems. The range of spatial dependency, however, is considerably smaller, which can be ascribed to the environmental extremities and other periglacial features. Based on the results, we recommend that, to obtain independent samples, the minimum distance between samples should be 10 m in Haplorthels or Haploturbels and 45 m in Histels.
Assessing Spring Thaw Nitrous Oxide Fluxes Simulated by the DNDC Model for Agricultural Soils
Authors: Kariyapperuma Kumudinie A. , Wagner-Riddle Claudia , Furon Adriana C. , Li Changsheng
Published: September 2012

Large N2O emissions from agricultural soils have been reported during winter and spring thaw. The objective of this study was to assess the ability of the DNDC model to simulate N2O emissions resulting from freeze–thaw cycles, particularly the timing of flux events. The DNDC model was tested against micrometeorological fluxes measured during 5 yr in Ontario, Canada. There was a very large discrepancy between simulated and observed fluxes in terms of magnitude and timing. The simulated event occurred, on average, 38 d later than observed, and N2O fluxes were up to 3.5 times larger than the highest measured flux. Examination of simulated soil conditions indicated that the mechanism underlying freeze–thaw‐induced N2O flux in the DNDC model, release of ice‐trapped N2O, was not correct. This misconception had not been identified before, possibly because cold conditions in previous studies were not as extreme as observed in our data set or because continuously measured N2O fluxes were not available for model assessment. As a result of this analysis, DNDC 9.1 was revised by removing the release of ice‐trapped N2O and adding N2O newly produced by denitrification in the surface layer as the main mechanism for N2O production (DNDC 9.3). Comparison between simulated N2O fluxes using DNDC 9.3 and our data indicated improved timing to within 1 d of observed events. The magnitude of simulated flux differed from measurements by more than a factor of two, however, suggesting that an improved algorithm for N2O production and diffusion under soil freezing and thawing is needed.
Measurement of Net Nitrogen and Phosphorus Mineralization in Wetland Soils Using a Modification of the Resin‐Core Technique
Authors: Noe Gregory B.
Published: September 2012

A modification of the resin‐core method was developed and tested for measuring in situ soil N and P net mineralization rates in wetland soils where temporal variation in bidirectional vertical water movement and saturation can complicate measurement. The modified design includes three mixed‐bed ion‐exchange resin bags located above and three resin bags located below soil incubating inside a core tube. The two inner resin bags adjacent to the soil capture NH4+, NO3−, and soluble reactive phosphorus (SRP) transported out of the soil during incubation; the two outer resin bags remove inorganic nutrients transported into the modified resin core; and the two middle resin bags serve as quality‐control checks on the function of the inner and outer resin bags. Modified resin cores were incubated monthly for a year along the hydrogeomorphic gradient through a floodplain wetland. Only small amounts of NH4+, NO3−, and SRP were found in the two middle resin bags, indicating that the modified resin‐core design was effective. Soil moisture and pH inside the modified resin cores typically tracked changes in the surrounding soil abiotic environment. In contrast, use of the closed polyethylene bag method provided substantially different net P and N mineralization rates than modified resin cores and did not track changes in soil moisture or pH. Net ammonification, nitrification, N mineralization, and P mineralization rates measured using modified resin cores varied through space and time associated with hydrologic, geomorphic, and climatic gradients in the floodplain wetland. The modified resin‐core technique successfully characterized spatiotemporal variation of net mineralization fluxes in situ and is a viable technique for assessing soil nutrient availability and developing ecosystem budgets.
Challenges in Understanding the Hydrologic Controls on the Mobility of Slow‐Moving Landslides
Authors: Wienhöfer Jan , Lindenmaier Falk , Zehe Erwin
Published: September 2012

Slow‐moving landslides are a wide‐spread type of active mass movement, can cause severe damages to infrastructure, and may be a precursor of sudden catastrophic slope failures. Pore‐water pressure is commonly regarded as the most important among a number of possible factors controlling landslide velocity. We used high‐resolution monitoring data to explore the relations of landslide mobility and hydrologic processes at the Heumöser landslide in Austria, which is characterized by continuous slow movement along a shear zone. Movement rates showed a seasonality that was associated with elevated pore‐water pressures. Pore pressure monitoring revealed a system of confined and separated aquifers with differing dynamics. Analysis of a simple infinite slope mobility model showed that small variations in parameters, along with measured pore pressure dynamics, provided a perfect match to our observations. Modeling showed a stabilizing effect of snow cover due to the additional load. This finding was supported by a multiple regression model, which further suggested that effective pore pressures at the slip surface were partially differing from the borehole observations and were related to preferential infiltration and subsurface flow in adjacent areas. It appears that in a setting like the Heumöser landslide, hydrologic processes delicately influence slope mobility through their control on pore pressure dynamics and the weight of the landslide body, which challenges observation and modeling. Moreover, it appears that their simplicity, and especially their high sensitivity to parameter variations, limits the conclusions that can be drawn from infinite slope models.