970 resultados para Disk plow
Resumo:
Citrus plants are the most important fruit species in the world, with emphasis to oranges, mandarins and lemons. In Rio Grande do Sul, Brazil, most fruit production is found on small properties under organic cultivation. Soil compaction is one of the factors limiting production and due to the fixed row placement of this crop, compaction can arise in various manners in the interrows of the orchard. The aim of this study was to evaluate soil physical properties and water infiltration capacity in response to interrow management in an orchard of mandarin (Citrus deliciosa Tenore 'Montenegrina') under organic cultivation. Interrow management was performed through harrowing, logs in em "V", mowing, and cutting/knocking down plants with a knife roller. Soil physical properties were evaluated in the wheel tracks of the tractor (WT), between the wheel tracks (BWT), and in the area under the line projection of the canopy (CLP), with undisturbed soil samples collected in the 0.00-0.15, 0.15-0.30, 0.30-0.45, and 0.45-0.60 m layers, with four replicates. The soil water infiltration test was performed using the concentric cylinder method, with a maximum time of 90 min for each test. In general, soil analysis showed a variation in the physical-hydraulic properties of the Argissolo Vermelho-Amarelo distrófico arênico (sandy loam Typic Paleudalf) in the three sampling sites in all layers, regardless of the management procedure in the interrows. Machinery traffic leads to heterogeneity in the soil physical-hydraulic properties in the interrows of the orchard. Soil porosity and bulk density are affected especially in the wheel tracks of the tractor (WT), which causes a reduction in the constant rate of infiltration and in the accumulated infiltration of water in this sampling site. The use of the disk harrow and mower leads to greater harmful effects on the soil, which can interfere with mandarin production.
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ABSTRACT Changes in carbon stocks in different compartments of soil organic matter of a clayey Latossolo Vermelho Distrófico (Typic Haplustox), caused by the substitution of native savanna vegetation (cerrado sensu stricto) by agroecosystems, were assessed after 31 years of cultivation. Under native vegetation, a stock of 164.5 Mg ha-1 C was estimated in the 0.00-1.00 m layer. After 31 years of cultivation, these changes in soil C stocks were detected to a depth of 0.60 m. In the case of substitution of cerrado sensu stricto by no-tillage soybean-corn rotation, a reduction of at least 11 % of the soil C pools was observed. However, the adoption of no-tillage as an alternative to tillage with a moldboard plow (conventional system) reduced CO2 emissions by up to 12 %.
Resumo:
ABSTRACT Tillage systems can influence C sequestration by changing aggregate formation and C distribution within the aggregate. This study was undertaken to explore the impact of no-tillage without straw (NT-S) and with straw (NT+S), and moldboard plow without straw (MP-S) and with straw (MP+S), on soil aggregation and aggregate-associated C after six years of double rice planting in a Hydragric Anthrosol in Guangxi, southwest of China. Soil samples of 0.00-0.05, 0.05-0.20 and 0.20-0.30 m layers were wet-sieved and divided into four aggregate-size classes, >2 mm, 2.00-0.25 mm, 0.25-0.053 and <0.053 mm, respectively, for measuring aggregate associated C and humic and fulvic acids. Results showed that the soil organic carbon (SOC) stock in bulk soil was 40.2-51.1 % higher in the 0.00-0.05 m layer and 11.3-17.0 % lower in the 0.05-0.20 m layer in NT system (NT+S and NT-S) compared to the MP system (MP+S and MP-S), respectively. However, no statistical difference was found across the whole 0.00-0.30 m layer. The NT system increased the proportion of >2 mm aggregate fraction and reduced the proportion of <0.053 mm aggregates in both 0.00-0.05 and 0.05-0.20 m layers. The SOC concentration, SOC stock and humic and fulvic acids within the >0.25 mm macroaggregate fraction also significantly increased in the 0.00-0.5 m layer in NT system. However, those within the 2.00-0.25 mm aggregate fraction were significantly reduced in the 0.05-0.200 m layer under NT system. Straw incorporation increased not only the SOC stock in bulk soil, but also the proportion of macroaggregate, aggregate associated with SOC and humic and fulvic acids concentration within the aggregate. The effect of straw on C sequestration might be dependent on the location of straw incorporation. In conclusion, the NT system increased the total SOC accumulation and humic and fulvic acids within macroaggregates, thus contributing to C sequestration in the 0.00-0.05 m layer.
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En Suisse, la variabilité géographique de la consommation de soins chirurgicaux est un domaine encore inexploré. Ce rapport examine de manière descriptive trois interventions chirurgicales réalisées en Suisse entre 2003 et 2005 : la prothèse partielle ou totale de hanche, la prothèse de genou et la cure de hernie discale. Il se concentre sur les caractéristiques démographiques des patients opérés, leur diagnostic et les différences des taux d'intervention selon les cantons. Les résultats sont présentés sous forme de taux bruts, de taux standardisés et de cartes géographiques de distribution.
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Backup warning system devices were evaluated to determine if they would alert winter maintenance snow plow drivers to obstacles directly behind the trailer and out of view of the driver when a unit is backed up. When the sensors on the back of the tow plow were covered with snow during plowing operations, the sensor would go off in the cab and continue going off, which would result in drivers turning the volume of the unit way down. One shop stated that the wireless transmitted signal would be hit or miss depending on the winter weather that they were operating in. The sensors on the back of the tow plow trailer would come in contact with salt brine and in this situation one of the sensors did go bad. The weatherproof box that was designed to keep the system waterproof did not fully keep the moisture out. It was found that the system did alert drivers of items behind the unit and there were no backup accidents reported during the research period.
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Carbapenemases should be accurately and rapidly detected, given their possible epidemiological spread and their impact on treatment options. Here, we developed a simple, easy and rapid matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)-based assay to detect carbapenemases and compared this innovative test with four other diagnostic approaches on 47 clinical isolates. Tandem mass spectrometry (MS-MS) was also used to determine accurately the amount of antibiotic present in the supernatant after 1 h of incubation and both MALDI-TOF and MS-MS approaches exhibited a 100% sensitivity and a 100% specificity. By comparison, molecular genetic techniques (Check-MDR Carba PCR and Check-MDR CT103 microarray) showed a 90.5% sensitivity and a 100% specificity, as two strains of Aeromonas were not detected because their chromosomal carbapenemase is not targeted by probes used in both kits. Altogether, this innovative MALDI-TOF-based approach that uses a stable 10-μg disk of ertapenem was highly efficient in detecting carbapenemase, with a sensitivity higher than that of PCR and microarray.
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Se da cuenta del hallazgo, en el SE de España de 28 especies, pertenecientes a: Uredinales (15, entre las cuales: Gymnosporangium confusum Plow., G. fuscum D. C., G. gracile P a t., Puccinia atropae Mont., P. barbeyi (Roum.) Magn., P. tumida Grev., Uromyces monspessulanus Tranzsch.), Ustilaginales (4), Tremelales (4, con Exidiopsis grisea (Pers.) Bdot. y Maire, E laccata (Bdot. y Galz.) Luck-Allen), Auriculariales (1), Septobasidiales (Septobasidium mariani Bres.) y Dacrimicetales (3, con Calocera palmata (Schum.) F r.).
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Two cases of a benign form of optic disc edema after successful trabeculectomy are reported. In both patients, optic disc edema was noted 2 to 4 weeks after trabeculectomy. The edema occurred without loss of visual acuity or field. The absolute intraocular pressure and intracranial pressure were normal--that is, the edema was not a syndrome of hypotony or pseudotumor cerebri. However, both patients had intracranial pressure in the high-normal range. The decrease in intraocular pressure into the low normal range after trabeculectomy may have altered the intracranial pressure:intraocular pressure ratio at the lamina cribrosa enough to produce optic disc edema.
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Provides instructions for using the computer program which was developed under the research project, "The Economics of Reducing the County Road System: Three Case Studies In Iowa". This program operates on an IBP personal computer with 300K storage. A fixed disk is required with at least 3 megabytes of storage. The computer must be equipped with DOS version 3.0; the programs are written in Fortran. The user's manual describes all data requirements including network preparation, trip information, cost for maintenance, reconstruction, etc. Program operation instructions are presented, as well as sample solution output and a listing of the computer programs.
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Total disc replacement (TDR) clinical success has been reported to be related to the residual motion of the operated level. Thus, accurate measurement of TDR range of motion (ROM) is of utmost importance. One commonly used tool in measuring ROM is the Oxford Cobbometer. Little is known however on its accuracy (precision and bias) in measuring TDR angles. The aim of this study was to assess the ability of the Cobbometer to accurately measure radiographic TDR angles. An anatomically accurate synthetic L4-L5 motion segment was instrumented with a CHARITE artificial disc. The TDR angle and anatomical position between L4 and L5 was fixed to prohibit motion while the motion segment was radiographically imaged in various degrees of rotation and elevation, representing a sample of possible patient placement positions. An experienced observer made ten readings of the TDR angle using the Cobbometer at each different position. The Cobbometer readings were analyzed to determine measurement accuracy at each position. Furthermore, analysis of variance was used to study rotation and elevation of the motion segment as treatment factors. Cobbometer TDR angle measurements were most accurate (highest precision and lowest bias) at the centered position (95.5%), which placed the TDR directly inline with the x-ray beam source without any rotation. In contrast, the lowest accuracy (75.2%) was observed in the most rotated and off-centered view. A difference as high as 4 degrees between readings at any individual position, and as high as 6 degrees between all the positions was observed. Furthermore, the Cobbometer was unable to detect the expected trend in TDR angle projection with changing position. Although the Cobbometer has been reported to be reliable in different clinical applications, it lacks the needed accuracy to measure TDR angles and ROM. More accurate ROM measurement methods need to be developed to help surgeons and researchers assess radiological success of TDRs.
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Phase II research included the following: (1) develop and evaluate alternative soil design and embankment construction specifications based on soil type, moisture, density, stability, and compaction process; (2) assess various quality control and acceptance procedures with a variety of in-situ test methods including the Dual-mass Dynamic Cone Penetrometer (DCP); and (3) develop and design rapid field soil identification methods. At the start of the research, soils were divided into cohesive and cohesionless soil types, with each category being addressed separately. Cohesionless soils were designated as having less than 36% fines content (material passing the No. 200 sieve) and cohesive soils as having greater than 36% fines content. Subsequently, soil categories were refined based not only on fines content but soil plasticity as well. Research activities included observations of fill placement, in-place moisture and density testing, and dual-mass DCP index testing on several highway embankment projects throughout Iowa. Experiments involving rubber-tired and vibratory compaction, lift thickness changes, and disk aeration were carried out for the full range of Iowa soils. By testing for soil stability the DCP was found to be a valuable field tool for quality control, whereby shortcomings from density testing (density gradients) were avoided. Furthermore, critical DCP index values were established based on soil type and compaction moisture content.
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Many accidents involving Iowa snowplows have happened in recent years. This study investigated the influence of time of day, sex of subject, type of snowplow sign and snowplow speed on the criteria of oncoming driver reaction time and his estimate of snowplow speed. Film strips were made of a car passing a snow-Plow under various experimental conditions. These experimental movie strips were viewed in the laboratory by college student drivers who were asked to indicate their reaction time to slow down and to estimate the speed of the snowplow being passed. The generally best sign condition for the snowplow was to have a striped rear sign and a speed-proportional flashing light in addition to the standard rotating beacon on top of the truck. Several recommendations were made.
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OBJECTIVES: To describe the clinical features of idiopathic chiasmal neuritis in a large cohort of patients and to report their visual and neurologic outcomes. DESIGN: A retrospective medical record review of consecutive patients with chiasmal neuritis at a single institution. Patients with clinical or radiographic evidence of inflammation involving the intraorbital optic nerve and patients with a systemic inflammatory or neoplastic disorder were excluded. RESULTS: Twenty patients were identified (14 female, 6 male; mean age, 37 years). Visual acuity at initial examination ranged from 20/15 to light perception. Progressive visual loss beyond 1 month was documented in 1 patient. Twelve of 15 patients who underwent magnetic resonance imaging demonstrated chiasmal enlargement and/or enhancement; 6 patients had 1 or more white matter lesions. Follow-up time ranged from 2 weeks to 22 years, with a mean of 5.7 years. The final median visual acuity was 20/20 (range, 20/15-20/50) and visual fields were normal or improved. Of 15 patients with a minimum follow-up interval of 1 year, 6 developed multiple sclerosis. CONCLUSIONS: The demographic and clinical features of idiopathic chiasmal neuritis resemble those of idiopathic optic neuritis. Visual prognosis is excellent. In this series, 40% of patients subsequently developed multiple sclerosis.