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1.
J Econ Entomol ; 110(3): 1052-1061, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28453741

RESUMO

The Hessian fly, Mayetiola destructor Say, is an important pest of winter wheat in the Southern Great Plains of the United States. As larvae feed behind the leaf sheath, infestations often go undetected until crop damage is evident, and there are no remedial actions that can prevent economic loss once a field is infested. The recent discovery of the sex-attractant pheromone of the Hessian fly provides an opportunity to use pheromone traps to detect and monitor adult activity and potentially better manage this pest. Adult male Hessian fly activity was monitored during 4 yr at six locations from northcentral Oklahoma, 36° N latitude, south to central Texas, 31° N latitude. In Oklahoma, trap captures were low in the fall, no flies were captured during the winter, and the largest number of flies was captured in the spring. However, in southcentral Texas, adults were captured throughout the fall, winter, and in the spring when trap captures were again the greatest. The relationship between trap captures and density of Hessian fly larvae per tiller was investigated during the fall and spring. Although large numbers of adults (>100 per trap per day) were often captured, economic infestation of larvae rarely developed. Results identify optimum times for field sampling to determine immature Hessian fly infestations in wheat in Oklahoma and Texas.


Assuntos
Dípteros/fisiologia , Controle de Insetos , Feromônios/farmacologia , Animais , Dípteros/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Oklahoma , Dinâmica Populacional , Estações do Ano , Texas , Triticum/crescimento & desenvolvimento
2.
J Integr Pest Manag ; 7(1): 12, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28446991

RESUMO

In 2013, the sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), a new invasive pest of sorghum species in North America, was confirmed on sorghum in 4 states and 38 counties in the United States. In 2015, the aphid was reported on sorghum in 17 states and over 400 counties as well as all sorghum-producing regions in Mexico. Ability to overwinter on living annual and perennial hosts in southern sorghum-producing areas and wind-aided movement of alate aphids appear to be the main factors in its impressive geographic spread in North America. Morphological characteristics of the sugarcane aphid include dark tarsi, cornicles, and antennae, allowing easy differentiation from other aphids on the crop. Sugarcane aphid damages sorghum by removing sap and covering plants with honeydew, causing general plant decline and yield loss. Honeydew and sooty mold can disrupt harvesting. The aphid's high reproductive rate on susceptible sorghum hybrids has resulted in reports of yield loss ranging from 10% to greater than 50%. In response, a combination of research-based data and field observations has supported development of state extension identification, scouting, and treatment guides that aid in initiating insecticide applications to prevent yield losses. Highly efficacious insecticides have been identified and when complemented by weekly scouting and use of thresholds, economic loss by sugarcane aphid can be minimized. Some commercial sorghum hybrids are partially resistant to the aphid, and plant breeders have identified other lines with sugarcane aphid resistance. A very diverse community of predators and parasitoids of sugarcane aphid has been identified, and their value to limit sugarcane aphid population growth is under investigation.

3.
Scand J Med Sci Sports ; 25(4): 509-16, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25212407

RESUMO

Growing evidence suggests that the nervous system contributes to non-contact knee ligament injury, but limited evidence has measured the effect of extrinsic events on joint stability. Following unanticipated events, the startle reflex leads to universal stiffening of the limbs, but no studies have investigated how an acoustic startle influences knee stiffness and muscle activation during a dynamic knee perturbation. Thirty-six individuals were tested for knee stiffness and muscle activation of the quadriceps and hamstrings. Subjects were seated and instructed to resist a 40-degree knee flexion perturbation from a relaxed state. During some trials, an acoustic startle (50 ms, 1000 Hz, 100 dB) was applied 100 ms prior to the perturbation. Knee stiffness, muscle amplitude, and timing were quantified across time, muscle, and startle conditions. The acoustic startle increased short-range (no startle: 0.044 ± 0.011 N·m/deg/kg; average startle: 0.047 ± 0.01 N·m/deg/kg) and total knee stiffness (no startle: 0.036 ± 0.01 N·m/deg/kg; first startle 0.027 ± 0.02 N·m/deg/kg). Additionally, the startle contributed to decreased [vastus medialis (VM): 13.76 ± 33.6%; vastus lateralis (VL): 6.72 ± 37.4%] but earlier (VM: 0.133 ± 0.17 s; VL: 0.124 ± 0.17 s) activation of the quadriceps muscles. The results of this study indicate that the startle response can significantly disrupt knee stiffness regulation required to maintain joint stability. Further studies should explore the role of unanticipated events on unintentional injury.


Assuntos
Instabilidade Articular/fisiopatologia , Articulação do Joelho/fisiologia , Músculo Quadríceps/fisiologia , Reflexo de Sobressalto/fisiologia , Estimulação Acústica , Adolescente , Adulto , Eletromiografia , Teste de Esforço , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fatores de Tempo , Adulto Jovem
4.
J Econ Entomol ; 107(2): 846-53, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24772569

RESUMO

Panicle caterpillars comprise an economically important insect pest complex of sorghum throughout the Great Plains of the United States, particularly in Kansas, Oklahoma, and Texas. The sorghum panicle caterpillar complex consists of larvae of two polyphagous lepidopteran species: the corn earworm, Helicoverpa zea (Boddie), and fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Sampling for panicle caterpillars in sorghum fields is usually accomplished by the beat bucket sampling technique with a fixed sample size of 30 beat bucket samples of one sorghum panicle each per 16.2 ha of field. We used Wald's sequential probability ratio test for a negative binomial distribution to develop a sequential sampling plan for panicle caterpillars. In total, 115 sorghum fields were sampled in Kansas, Oklahoma, and Texas from June to August 2010. Panicle caterpillars had an aggregated distribution of counts confirmed by Pearson's chi-square statistic for lack of fit to the negative binomial distribution for each sampled field. A sequential sampling plan was developed using a high threshold (an economic threshold) of 0.5 caterpillars per sorghum panicle, a low threshold (a safe level) of 0.20 caterpillars per panicle, and fixed error rates (alpha = 0.10 and beta = 0.05). At caterpillar densities > 0.45 and < 0.12 per panicle, the average number of panicles inspected to make a decision was less than the current recommendation of 30. In a 2013 validation test of 25 fields, the expected number of samples taken from average sample number curve was in close agreement with the number of samples required using the sequential plan (r2 = 0.93), and all fields were correctly classified when compared with a fixed sample size result. The plan improved upon current sampling recommendations for panicle caterpillars in sorghum because at known acceptable fixed error rates fewer samples were required when caterpillars are scarce or abundant, whereas more samples were required to make decisions with the same acceptable error rates when densities were near the economic thresholds.


Assuntos
Controle de Insetos/métodos , Mariposas/fisiologia , Sorghum/crescimento & desenvolvimento , Distribuição Animal , Animais , Flores/crescimento & desenvolvimento , Kansas , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Oklahoma , Densidade Demográfica , Estações do Ano , Texas
5.
EuroIntervention ; 7: 1-2, 2011.
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1062728

RESUMO

Aims: We report the angiographic and clinical outcomes of patients with de novocoronary bifurcation lesions treated with the Nile PAX dedicated device.Methods and results: From Dec/08 to Mar/09, a total of 102 pts with singlebifurcation lesion were prospectively enrolled in this non-randomised, multicenter(10 sites in Europe/South America) study. Lesion criteria were vessel size 2.5-3.5mm in the parent vessel (PV) and 2.0-3.0 mm in the SB, and lesion length <14 mmin the PV. Clinical follow-up (FU) was scheduled at 1, 3, 6, 9 and 12 months, andyearly up to 5 years. Angiographic FU was scheduled at 9 months (primaryendpoint). Angiographic analysis was performed by an independent angiographiccore laboratory. Data analysis and management was performed by an independentdata coordinating center; also, all clinical events were independently adjudicatedby a clinical events committee. Mean age was 63 years, 29% had diabetes, 16previous MI, and 40% previous intervention. The LAD/Dg was the most prevalentlocation (75%), and 60% had significant involvement of both branches. In theprocedure, PV was predilated in 97%; the study stent was successfully attemptedand implanted in 99%. Overall, 25% of SB received an additional stent; and 94%of lesions had final kissing-balloon inflation. By quantitative coronary angiography,baseline mean lesion length, vessel diameter and% diameter stenosis were: 10.9mm, 2.99 mm and 72% in the PV, and 4.1 mm, 2.28 mm, and 38% in the SB, respectively. Angiographic success (residual stenosis <50%, final TIMI 3 flow, andabsence of dissection) was achieved in 98%. There was only 1 major adversecardiac event (MACE) during hospitalisation, which was adjudicated as a non-Qmyocardial infarction during hospitalisation, and no additional adverse events werereported up to 30 days...


Assuntos
Angiografia , Diabetes Mellitus , Revascularização Miocárdica
6.
J Econ Entomol ; 101(5): 1624-32, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18950045

RESUMO

Larvae of Phyllophaga spp. (Coleoptera: Scarabaeidae) are important turfgrass pests in many regions of the United States. However, not all of the species associated with turfgrass are known, including species most likely to be of economic concern in Oklahoma turfgrasses, especially Bermuda grass. This study documented the species composition and seasonal occurrence of Phyllophaga associated with high maintenance Bermuda grass turf in Oklahoma over a 2-yr period. In 2005 and 2006, adult Phyllophaga spp. were collected with blacklight traps from selected golf courses throughout Oklahoma Phyllophaga larvae were obtained from Bermuda grass stands at selected sod production facilities adjacent to or near the light traps. We collected 20 species of Phyllophaga beetles in light traps, and nine species of Phyllophaga larvae from turfgrass. Peak flight periods for most species occurred in May and June, but some were captured as early as mid-April and others as late as September. The cytochrome c oxidase I (COI) gene from adults and larvae was amplified using polymerase chain reaction, sequenced, and then used to compare larval DNA against DNA from identified adults. These results confirmed the validity of using COI sequences to identify species of some Phyllophaga larvae. The identifications will aid in optimizing the timing of insecticide applications against Phyllophaga white grubs as discussed.


Assuntos
Besouros/classificação , Cynodon/parasitologia , Estações do Ano , Animais , Besouros/genética , Besouros/crescimento & desenvolvimento , DNA/química , Larva/classificação , Larva/genética , Larva/fisiologia , Oklahoma , Filogenia , Análise de Sequência de DNA
7.
Proc Natl Acad Sci U S A ; 104(41): 16204-8, 2007 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-17923672

RESUMO

Corn (Zea mays L.) that has been genetically engineered to produce the Cry1Ab protein (Bt corn) is resistant to lepidopteran pests. Bt corn is widely planted in the midwestern United States, often adjacent to headwater streams. We show that corn byproducts, such as pollen and detritus, enter headwater streams and are subject to storage, consumption, and transport to downstream water bodies. Laboratory feeding trials showed that consumption of Bt corn byproducts reduced growth and increased mortality of nontarget stream insects. Stream insects are important prey for aquatic and riparian predators, and widespread planting of Bt crops has unexpected ecosystem-scale consequences.


Assuntos
Ecossistema , Plantas Geneticamente Modificadas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/genética , Toxinas Bacterianas/toxicidade , Endotoxinas/genética , Endotoxinas/toxicidade , Água Doce/análise , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/toxicidade , Insetos , Lepidópteros/patogenicidade , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Pólen , Zea mays/genética , Zea mays/parasitologia , Zea mays/toxicidade
8.
J Environ Qual ; 36(2): 408-15, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17255628

RESUMO

Agriculture is a major nonpoint source of phosphorus (P) in the Midwest, but how surface runoff and tile drainage interact to affect temporal concentrations and fluxes of both dissolved and particulate P remains unclear. Our objective was to determine the dominant form of P in streams (dissolved or particulate) and identify the mode of transport of this P from fields to streams in tile-drained agricultural watersheds. We measured dissolved reactive P (DRP) and total P (TP) concentrations and loads in stream and tile water in the upper reaches of three watersheds in east-central Illinois (Embarras River, Lake Fork of the Kaskaskia River, and Big Ditch of the Sangamon River). For all 16 water year by watershed combinations examined, annual flow-weighted mean TP concentrations were >0.1 mg L(-1), and seven water year by watershed combinations exceeded 0.2 mg L(-1). Concentrations of DRP and particulate P (PP) increased with stream discharge; however, particulate P was the dominant form during overland runoff events, which greatly affected annual TP loads. Concentrations of DRP and PP in tiles increased with discharge, indicating tiles were a source of P to streams. Across watersheds, the greatest DRP concentrations (as high as 1.25 mg L(-1)) were associated with a precipitation event that followed widespread application of P fertilizer on frozen soils. Although eliminating this practice would reduce the potential for overland runoff of P, soil erosion and tile drainage would continue to be important transport pathways of P to streams in east-central Illinois.


Assuntos
Agricultura/métodos , Fósforo/análise , Movimentos da Água , Poluentes Químicos da Água/análise , Chuva , Rios/química , Neve , Abastecimento de Água
9.
Mult Scler ; 12(5): 613-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17086908

RESUMO

Patients with multiple sclerosis (MS) present with varying symptoms that can differ between and within individuals. As new interventions and drug treatments become available to MS patients, it is essential to understand the relationship between fatigue and the variability of functional mobility measures in order to define a meaningful change due to treatment within the MS population. The purpose of this study was to examine the within-day and between-day changes in gait variability for subjects with MS in fresh and fatigued conditions. Walking gait parameters were measured from 20 subjects diagnosed with MS and eight healthy control subjects. Standard deviations of hip, knee and ankle kinematic and kinetic variables were quantified as the measure of variability and analysed with a two-way (group by condition) ANOVA. Results indicated MS subjects had significantly greater hip (P <0.020), knee (P <0.011) and ankle (P <0.034) joint angle variability than control subjects, but variability was not different between conditions. Kinetic variability was not different between groups or conditions. MS subjects in this study walked more slowly than the healthy controls and they also reported more fatigue. Research examining treatment effects within the MS population should account for increased levels of kinematic gait variability.


Assuntos
Ritmo Circadiano/fisiologia , Marcha/fisiologia , Esclerose Múltipla/diagnóstico , Esclerose Múltipla/fisiopatologia , Adulto , Fenômenos Biomecânicos , Avaliação da Deficiência , Fadiga/diagnóstico , Fadiga/fisiopatologia , Feminino , Humanos , Articulações/fisiopatologia , Locomoção/fisiologia , Masculino , Pessoa de Meia-Idade , Medição da Dor , Amplitude de Movimento Articular , Valores de Referência , Fatores de Tempo
10.
Percept Mot Skills ; 103(3): 685-92, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17326490

RESUMO

This study compared balance, sway, and weight shift among golfers with different skill levels. Participants (N=52) were right-handed, male golfers between the ages of 18 and 55 and were divided into 3 groups based on their official handicap (Group 1= 0-9, Group 2= 10-16, Group 3 = 17+). Postural sway velocity was recorded unilaterally for each leg and bilaterally. Weight shift as assessed by limits of stability was measured as movement velocity and directional control. During testing, participants stood on a virtual center square as illustrated by a monitor placed directly in front of them. On command participants initiated movement about eight target squares located in a circle around the center square and attempted to move quickly and accurately to the targets. Means from the three forward, three backward, three left, and three right targets were analyzed by group. While significant condition means existed for each of the analyzed means, no significant group differences were found for bilateral or unilateral postural sway, and no significant group differences were found for movement velocity or directional control. In conclusion, as measured in the current study, balance and weight shift are not significantly different among golfers with different skill.


Assuntos
Peso Corporal , Golfe , Competência Profissional , Adolescente , Adulto , Traumatismos em Atletas/diagnóstico , Traumatismos em Atletas/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Equilíbrio Postural , Inquéritos e Questionários
11.
J Econ Entomol ; 98(1): 95-102, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15765670

RESUMO

The effects of planting date and application rate of imidacloprid for control of Schizaphis graminum Rondani, Rhopalosiphum padi L. (Homoptera: Aphididae), and barley yellow dwarf virus (BYDV) in hard red winter wheat were studied. The first experiment was conducted from 1997 to 1999 at two locations and consisted of three planting dates and four rates of imidacloprid-treated seed. The second experiment was conducted from 2001 to 2002 in Stillwater, OK, and consisted of two varieties of hard red winter wheat seed and four rates of imidacloprid. Aphid densities, occurrence of BYDV, yield components, and final grain yield were measured, and yield differences were used to estimate the economic return obtained from using imidacloprid. In the first study, aphid populations responded to insecticide rate in the early and middle plantings, but the response was reduced in the late planting. Yields increased as insecticide rate increased but did not always result in a positive economic return. In the second study, imidacloprid seed treatments reduced aphid numbers and BYD occurrence, protected yield, and resulted in a positive economic return. The presence of aphids and BYDV lowered yield by reducing fertile head density, total kernel weight, and test weight. Whereas the application of imidacloprid seed treatments often provided positive yield protection, it did not did not consistently provide a positive economic return. A positive economic return was consistently obtained if the cereal aphid was carrying and transmitting BYDV and was more likely to occur if wheat was treated with a low rate if imidacloprid and planted in a "dual purpose" planting date window.


Assuntos
Agricultura/métodos , Afídeos , Imidazóis/administração & dosagem , Inseticidas/administração & dosagem , Luteovirus , Triticum/economia , Agricultura/economia , Animais , Neonicotinoides , Nitrocompostos , Controle de Pragas/métodos , Estações do Ano , Triticum/crescimento & desenvolvimento , Triticum/virologia
12.
J Econ Entomol ; 96(5): 1585-93, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14650535

RESUMO

The numbers of greenbugs, Schizaphis graminum (Rondani), and bird cherry-oat aphids, Rhopalosiphum padi L., per wheat tiller (stem) were estimated in 189 production winter wheat (Triticum aestivum L.) fields located throughout Oklahoma. Taylor's power law regressions were calculated from these data and used to construct fixed precision sequential sampling schemes for each species. An evaluation data set was constructed from 240 samples taken during three growing seasons from winter wheat fields at four locations in Oklahoma. Wheat cultivar and growth stage were recorded for each field on the day of sampling. Taylor's power law parameters for evaluation fields differed significantly for both species among growing seasons, locations, and plant growth stages. Median precision achieved using the fixed precision sequential sampling schemes for each species departed <20% from expected precision over the range population intensity in the evaluation data. For the 10% of samples with greatest deviation between observed and expected precision, observed precision was 13.8-81.8% greater than that expected precision depending on aphid species and population intensity. For the greenbug, the distribution of the percentage deviation between observed and expected precision was positively skewed, so that the sampling scheme tended to over-predict precision. For the bird cherry-oat aphid, the distribution was more symmetric. Even though precision observed using the sampling schemes frequently varied from expected precision, because of the inevitable consequence of sampling error and environmental variation, the sampling schemes yielded median observed precision levels close to expected precision levels over a broad range of population intensity.


Assuntos
Afídeos/fisiologia , Hemípteros/fisiologia , Triticum/crescimento & desenvolvimento , Agricultura/métodos , Animais , Oklahoma , Densidade Demográfica
13.
J Econ Entomol ; 95(1): 89-95, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11942769

RESUMO

The effect of greenbug, Schizaphis graminum (Rondani), feeding on the yield of four winter wheat cultivars commonly grown in Oklahoma was studied. Cultivars tested were 'Karl', a recent derivative 'Karl-92', and '2163', all greenbug-susceptible cultivars; and 'TAM-110', a cultivar with resistance to biotype E greenbugs. The objectives were to determine the effect of different greenbug densities during fall and spring on yield of winter wheat, and to develop mathematical models to quantify the effect of greenbugs on yield loss. The intensity of greenbug infestations achieved in plots by artificial infestation varied among years and growing seasons within a year, but was generally sufficient to cause a reduction in yield. Among yield components, the number of heads per square meter and the number of seeds per head were frequently negatively correlated with the accumulated number of greenbug-days per tiller. Seed weight was rarely affected by greenbug infestation. A regression model estimated yield loss for greenbug-susceptible cultivars at 0.51 kg/ha loss of yield per greenbug-day in years with near normal precipitation, and a loss of 1.17 kg/ha under severe drought conditions. The susceptible winter wheat cultivars exhibited similar yield loss in relation to the intensity of greenbug infestation, as indicated by a common slope parameter in the regression model. Results suggest that the model is robust for predicting yield loss for susceptible cultivars.


Assuntos
Afídeos , Produtos Agrícolas/economia , Triticum/economia , Animais , Modelos Econométricos , Estações do Ano
16.
J Infus Nurs ; 24(5): 326-31, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11575048

RESUMO

The article describes the institution of a cost-effective, efficient, nurse-driven advanced intervention for peripherally inserted central catheter (PICC) placement using microintroducers and venous ultrasound. Obstacles are identified and steps taken to overcome these obstacles are described. The importance of gathering support from key groups including the i.v. Team is discussed. Results showed a significant cost savings and additional benefits. Nurse-driven interventional technology is a positive advancement in the placing of PICCs.


Assuntos
Cateterismo Venoso Central , Análise Custo-Benefício , Cateterismo Venoso Central/economia , Cateterismo Venoso Central/métodos , Cateterismo Venoso Central/enfermagem , Cateterismo Venoso Central/tendências , Humanos
17.
Environ Manage ; 27(4): 627-36, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11289459

RESUMO

Theoretical constructs, such as the river continuum concept, predict that the composition of benthic fauna in rivers will be different from that of headwater streams. There exists a need to modify, for use on larger rivers, the bioassessment techniques commonly used on small streams. Using aquatic macroinvertebrates and the "reference condition" approach, we developed and tested a multimetric index for use on the rivers of Idaho. Reference sites were selected to represent the best current conditions (i.e., least impacted) among Idaho rivers. The index performed well in distinguishing reference sites from sites displaying some form of anthropogenic impairment. Individual metrics used in the index included: number of EPT taxa, total number of taxa, percent dominant taxon, percent Elmidae, and percent predators. The index we developed for Idaho rivers was essentially a modification of a framework designed for small streams, suggesting that techniques, including data analysis, currently used for streams can be adapted for use on larger rivers. Adapting these methods for use in rivers is primarily a matter of (1) selecting metrics relevant to the rivers of interest; (2) expanding the field sampling to encompass the greater habitat area and, potentially, heterogeneity of rivers; and (3) selecting an appropriate form of data analysis. The approach we describe here should be applicable to geographic regions other than Idaho.


Assuntos
Monitoramento Ambiental/métodos , Invertebrados , Poluentes da Água/efeitos adversos , Animais , Bioensaio/métodos , Ecossistema , Geografia , Dinâmica Populacional
18.
ScientificWorldJournal ; 1 Suppl 2: 597-604, 2001 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-12805881

RESUMO

The Midwest has large riverine exports of nitrogen (N), with the largest flux per unit area to the Mississippi River system coming from Iowa and Illinois. We used historic and current data to estimate N inputs, outputs, and transformations for Illinois where human activity (principally agriculture and associated landscape drainage) have had a dominant impact. Presently, approximately 800,000 Mg of N is added each year as fertilizer and another 420,000 Mg is biologically fixed, primarily by soybean (Glycine max L. Merr.). These annual inputs are greater than exports in grain, which results in surplus N throughout the landscape. Rivers within the state export approximately 50% of this surplus N, mostly as nitrate, and the remainder appears to be denitrified or temporarily incorporated into the soil organic matter pool. The magnitude of N losses for 1880, 1910, 1950, and 1990 are compared. Initial cultivation of the prairies released large quantities of N (approximately 500,000 Mg N year(-1)), and resulted in riverine N transport during the late 19th century that appears to have been on the same order of magnitude as contemporary N losses. Riverine flux was estimated to have been at a minimum in about 1950, due to diminished net mineralization and low fertilizer inputs. Residual fertilizer N from corn (Zea mays L.), biological N fixed by soybean, short-circuiting of soil water through artificial drainage, and decreased cropping-system diversity appear to be the primary sources for current N export.


Assuntos
Agricultura , Fertilizantes/análise , Água Doce/química , Nitrogênio/metabolismo , Agricultura/história , Agricultura/estatística & dados numéricos , Animais , Animais Domésticos , Produtos Agrícolas/metabolismo , Poluentes Ambientais/análise , Poluentes Ambientais/metabolismo , Fertilizantes/história , Fertilizantes/estatística & dados numéricos , Abastecimento de Alimentos , História do Século XIX , História do Século XX , Illinois , Nitrogênio/análise , Fixação de Nitrogênio , Solo/análise , Movimentos da Água
19.
Arch Mal Coeur Vaiss ; 94(12): 1409-12, 2001 Dec.
Artigo em Francês | MEDLINE | ID: mdl-11828927

RESUMO

Ruptures of sinus of Valsalva aneurysms are a rare complication, and very few cases of rupture in the left atrium have been described. In this clinical case we report the case of a patient hospitalised with a scenario of cardiac insufficiency revealing a very large posterior sinus of Valsalva aneurysm, associated with a bicuspid aortic valve, and rupture in the left atrium. The diagnosis was by transthoracic and transoesophageal multiplan echocardiography, and the treatment surgical, with a good result.


Assuntos
Aneurisma Aórtico/patologia , Ruptura Aórtica/patologia , Seio Aórtico/patologia , Idoso , Aneurisma Aórtico/diagnóstico por imagem , Aneurisma Aórtico/cirurgia , Ruptura Aórtica/diagnóstico por imagem , Ruptura Aórtica/cirurgia , Ecocardiografia/métodos , Átrios do Coração , Insuficiência Cardíaca/complicações , Humanos , Masculino , Seio Aórtico/diagnóstico por imagem , Seio Aórtico/cirurgia , Resultado do Tratamento
20.
J Econ Entomol ; 93(5): 1522-30, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11057727

RESUMO

From 1997 to 1999, Schizaphis graminum (Rondani), intensity (number per tiller) was estimated on 115 occasions from hard red winter wheat fields located throughout the major wheat growing regions of Oklahoma. A total of 32 and 83 fields was sampled during the fall and spring, respectively. The parameters of linear regressions relating the mean number of greenbugs per tiller (m) and the proportion of infested tillers (PT) differed significantly between fall and spring infestations. The PT-m linear model provided a good fit for data on S. graminum for fall and spring infestations at tally thresholds of 0, 1, 2, and 3. A tally threshold (T) represents the number of greenbugs present on a tiller before the tiller is classified as infested by >T greenbugs. A regression model with a tally threshold of 2 was the most precise for classifying S. graminum populations during fall growth of winter wheat because it explained a greater amount of the variation in the PT-m relationship (97%) than models with other tally thresholds. A separate spring model with a tally threshold of 1 was the most precise for classifying S. graminum populations during spring growth of winter wheat. Sequential sampling stop lines based on sequential probability ratio tests were calculated for economic thresholds of 3 or 6 greenbugs per tiller for fall infestations and 6 or 9 greenbugs per tiller for spring infestations. With the newly developed parameters, the average sample number required to classify greenbug populations near economic thresholds (as above or below the economic threshold) varied from 69 to 207. We expect that the sampling plans for greenbugs in winter wheat developed during this study will be efficient and useful tools for consultants and producers in the southern plains.


Assuntos
Afídeos , Triticum , Animais , Oklahoma , Densidade Demográfica , Estações do Ano
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