2,538,383 research outputs found
Root growth and soil nitrogen depletion by onion, lettuce, early cabbage and carrot
Experiments examining root growth, the utilization of N and the effect of green manures were carried out on four vegetable crops. Large differences were observed both in rooting depth penetration rates, and in final rooting depth and distribution. Onion had a very low depth penetration rate, carrot an intermediate rate, and lettuce and cabbage showed high rates. A combination of depth penetration rates and duration of growth determined rooting depth at harvest. Therefore, lettuce, which had a very short growing season, had a shallow root system at harvest, whereas carrot with a lower depth penetration rate but a long growing season had deep rooting at harvest. The final rooting depth of the vegetables varied from approximately 0.3 m for onion to more than 1.0 m for carrot and early cabbage. Carrot and cabbage were able to utilize N from deeper soil layers, not available to onion and lettuce. The ability of green manure crops to concentrate available N in the upper soil layers was especially valuable when they were grown before the two shallow rooted crops
Lightweight Data Integration Frameworks for Clinical Research
Research data from a single clinical study is often spread across multiple applications and systems. We present a reusable, lightweight, secure framework for automatically integrating and querying study data from heterogeneous sources in order to answer routine, operational questions for researchers
THE TECHNIQUES OF TEACHING ENGLISH VOCABULARY AT SLTPN 1 KEDUNGADEM-BOJONEGORRO
There are many technique used by the teacher in teaching English vocabulary. So far, based on the English curriculum for the junior High School describes a mastery of approximately 1000 vocabulary. As we know that vocabulary is one of the fundamental factors that make it possible for a person to speak a language in a communicative way. For this purpose, teaching English vocabulary need special technique in order to help the studentās English mastery. The problem of this study are(1) What is the techniques used by the teacher in teaching English vocabulary at SLPN 1 Kedungadem-Bojonegoro? (2) What is the teacherās reason choosing the techniques in teaching English vocabulary at SLTPN 1 Kedungadem- Bojonegoro? (3) What is the studentās perception toward the technique used by the teacher in teaching English vocabulary at SLTPN1 Kedungadem-Bojonegoro? Accordingly, the purpose of the study are: (1) To know the teaching technique used by the teacher in teaching English vocabulary at SLTPN 1 Kedungadem-Bojonegoro, (2) To know the reasonās of choosing the techniques used by the teacher in teaching English vocabulary at SLTPN 1 Kedungadem-Bojonegoro, (3) To know the studentās perception toward the techniques of teaching vocabulary used by the teacher. This study uses a descriptive qualitative design to obtain data concerning the research problem. The sample of this study consisT of one English teacher and 39 students in the first years. The data of this study are collected by applying interview, observation and questionnaires. The interview just for the first English teacher at SLTPN 1 Kedungadem- Bojonegoro, While an observation to the classroom and the questionnaire for the first student of SLTPN 1 Kedungadem-Bojonegoro. The result of this study show that the technique used by the teacher who is teaching in the classroom are dialoque, drill and games.The reason of choosing the techniques is to avoid the student get bored and bring the studentsā concentration on learning vocabulary. At last, the games techniques are suitable to be applied in teaching learning process, especially on teaching English vocabulary at SLTPN 1 Kedungadem-Bojonegoro. They will help the students to learn English vocabulary and facilitate their rapid understanding of the English materials
Seasonal Change on Land and Water
The purpose of this resource is to further students' understanding of the causes of seasonal change using visualizations to compare the effects of incoming solar energy in the two hemispheres. The class reviews global visualizations of incoming sunlight and surface temperature and discusses seasonal change. Students use the visualizations to support inquiry on the differences in seasonal change in the Northern and Southern Hemispheres, culminating in an evidence-based argument about why one hemisphere experiences warmer summers although it receives less total solar energy. Educational levels: Middle school, High school
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On the use of testability measures for dependability assessment
Program ātestabilityā is informally, the probability that a program will fail under test if it contains at least one fault. When a dependability assessment has to be derived from the observation of a series of failure free test executions (a common need for software subject to āultra high reliabilityā requirements), measures of testability can-in theory-be used to draw inferences on program correctness. We rigorously investigate the concept of testability and its use in dependability assessment, criticizing, and improving on, previously published results. We give a general descriptive model of program execution and testing, on which the different measures of interest can be defined. We propose a more precise definition of program testability than that given by other authors, and discuss how to increase testing effectiveness without impairing program reliability in operation. We then study the mathematics of using testability to estimate, from test results: the probability of program correctness and the probability of failures. To derive the probability of program correctness, we use a Bayesian inference procedure and argue that this is more useful than deriving a classical āconfidence levelā. We also show that a high testability is not an unconditionally desirable property for a program. In particular, for programs complex enough that they are unlikely to be completely fault free, increasing testability may produce a program which will be less trustworthy, even after successful testin
Optical/infrared observations of the X-ray burster KS1731-260 in quiescence
We performed an optical/infrared study of the counterpart of the low-mass
X-ray binary KS1731-260 to test its identification and obtain information about
the donor. Optical and infrared images of the counterpart of KS1731-260 were
taken in two different epochs (2001 and 2007) after the source returned to
quiescence in X-rays. We compared those observations with obtained when KS
1731-260 was still active. We confirm the identification of KS1731-260 with the
previously proposed counterpart and improve its position to RA=17:34:13.46 and
DEC=-26:05:18.60. The H-band magnitude of this candidate showed a decline of
~1.7 mags from outburst to quiescence. In 2007 April we obtained R=22.8+-0.1
and I=20.9+-0.1 for KS1731-260. Similar optical brightness was measured in June
2001 and July 2007. The intrinsic optical color R-I is consistent with spectral
types from F to G for the secondary although there is a large excess over that
from the secondary at the infrared wavelengths. This may be due to emission
from the cooler outer regions of the accretion disk. We cannot rule out a brown
dwarf as a donor star, although it would require that the distance to the
source is significantly lower than the 7 kpc reported by Muno et al. 2000.Comment: Accepted for publication in A&
Test 2018A: Case IH Magnum 260
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of the tests in this booklet, and available test reports is to provide users with data for comparisons of performance among tractor models. General Tractors are tested at the University of Nebraska according to test procedures of the OECD (Organization of Economic Cooperation and Development), the SAE (Society of Automotive Engineers) International and the ASABE (American Society of Agricultural and Biological Engineers). The three codes are technically equivalent, but do differ slightly. For the past 10 years, the majority of tests have been performed according to the OECD codes. The manufacturer selects the tractor to be tested from its production line, provides the specifications, and certifies that the tractor is a stock model. Each tractor is equipped with the common energy consuming accessories (power steering, PTO, implement lifts, etc.). Any power consuming accessory may be disconnected when the means for doing so can be reached from the operator position. A manufacturer\u27s representative is present during the tests to as certain that the tractor gives its optimum performance. Weight can be added to the tractor to improve drawbar performance in certain tests. Static tire loads and inflation pressures must conform to the specifications of the Tire and Rim Association or to weight limits set by the manufacturer. Specifications All manufacturers provide the Laboratory with detailed specifications which are required for the tests. The Nebraska Tractor Test report provides only a limited amount of data due to space constraints. Preparation for Test The tractor is required to have been limbered up by the manufacturer for a sufficient number of hours; if this was not done, this limber- up is performed at the Tractor Test Lab. Adjustments are permitted during this period. After the start of the official test, no adjustments can be made. Any adjustments. repairs, alterations or replacements are mentioned in the final Nebraska Tractor Test report. At this time, instrumentation for measuring engine rpm, fan speed, temperatures and pressures is installed on the tractor. The tractor is also provided with connections to the Lab\u27s fuel supply. PTO Performance The tractor PTO is connected to a dynamometer, which is a device for putting a load on the tractor and measuring the power generated by the tractor. During the preliminary runs, the manufacturer is allowed to make some adjustments to optimize the performance. These adjustments, which include the injection pump volume and timing and the high idle set within the specified range, will remain during the whole test program and must be settings guaranteed by the manufacturer. The tests are performed while maintaining an ambient temperature of 75Ā°F (24Ā°C) and at a barometer reading above 28.5 inches Hg (96.6 kPa). Data are taken at intervals after the tractor performance has stabilized. Inlet fuel temperatures are also maintained at a predetermined level. The throttle being set for maximum no-load rpm (High Idle), an increasing load is applied to the PTO by the dynamometer along the operating curve of the engine. The full test report will show the torque, rpm, power and fuel consumption data obtained at Rated Engine speed, Standard PTO speed (either 1000 or 540 rpm), the maximum power on the curve and the torque rise. Drawbar Performance Tests are performed in all gears between one gear below the one at Which 15% slip occurs and a maximum speed of 10 mph (16.1 km/h). In each gear, the throttle is set for maximum speed (High Idle) and the drawbar load increased until maximum drawbar power is obtained. The drawbar load is created by towing load units behind the test-and- measurement vehicle which, itself, is hitched to the tested tractor\u27s drawbar. For each load, measurements and calculations are made to determine drawbar pull, speed, drawbar power, slip and fuel consumption. All measurements are recorded at intervals after the tractor\u27s condition is stabilized. No operational limits set by the manufacturer can be exceeded. A second test series investigates the part loads at 75% and 50% of the drawbar load at Rated Engine Speed in a gear close to 4.6 mph (7.5 km/h) and in the gear where maximum drawbar power was obtained. Sound Measurement Sound measurement is made on the test track in two locations-at the driver\u27s ear and in a location representing bystander noise. The tests at the driver\u27s ear are performed in several gears and under a number of conditions, but only the maximum level is reported. The bystander sound test is performed with the microphone located at 25 ft (7.5 m) from the centerline of the tractor which is accelerating from a lower speed to full speed in its top gear. The OECD procedure differs. The SAE/ASABE procedures and only the numbers for the same gears and same load conditions can be compared. The SAE/ASABE procedure measures sound in only one gear under different load conditions, whereas the GECD procedure measures sound in different gears between High Idle and Rated Engine speed. For tractors with Mechanical Front Wheel Drive, operator- ear measurements are made with the front-wheel drive engaged and disengaged. Hydraulic Lift Capacity and Flow Hydraulic lift capacity is measured in a special test stand. A frame is fitted to the three-point hitch lift links. Measurements of lift capacity are taken at the hitch points and at a point 24 (610 mm) behind the hitch points when the lower links are horizontal. The load is applied with a hydraulic cylinder and the arms move stepwise through the lift range. The number which is reported is 90% of the load which can be carried throughout the lift range. The booklet reports the lift capacity at 24 (610 mm) behind the hitch points. A second test determines the pressure/flow relationship and performance of the hydraulic system for supplying power to external hydraulic cylinders or hydraulic motors. The Nebraska report provides data on delivery rate, pressure and available powe
Low-Temperature and High-Pressure Induced Swelling of a Hydrophobic Polymer-Chain in Aqueous Solution
We report molecular dynamics simulations of a hydrophobic polymer-chain in
aqueous solution between and at pressures of ,
, and . The simulations reveal a hydrophobically
collapsed state at low pressures and high temperatures. At and
about and at and about , however, a transition
to a swelled state is observed. The transition is driven by a smaller volume
and a remarkably strong lower enthalpy of the swelled state, indicating a steep
positive slope of the corresponding transition line. The swelling is stabilized
almost completely by the energetically favorable state of water in the polymers
hydrophobic first hydration shell at low temperatures. Although surprising,
this finding is consistent with the observation of a positive heat capacity of
hydrophobic solvation. Moreover, the slope and location of the observed
swelling transition for the collapsed hydrophobic chain coincides remarkably
well with the cold denaturation transition of proteins.Comment: 9 pages, 9 figures, twocolumn revte
A role for Syk-kinase in the control of the binding cycle of the Ī²2 integrins (CD11/CD18) in human polymorphonuclear neutrophils
A fine control of Ī²2 integrin (CD11/CD18)-mediated firm adhesion of human neutrophils to the endothelial cell monolayer is required to allow ordered emigration. To elucidate the molecular mechanisms that control this process, intracellular protein tyrosine signaling subsequent to Ī²2 integrin-mediated ligand binding was studied by immunoprecipitation and Western blotting techniques. The 72-kDa Syk-kinase, which was tyrosine-phosphorylated upon adhesion, was found to coprecipitate with CD18, the Ī²-subunit of the Ī²2 integrins. Moreover, inhibition of Syk-kinase by piceatannol enhanced adhesion and spreading but diminished N-formyl-Met-Leu-Phe-induced chemotactic migration. The enhancement of adhesiveness was associated with integrin clustering, which results in increased integrin avidity. In contrast, piceatannol had no effect on the surface expression or on the affinity of Ī²2 integrins. Altogether, this suggests that Syk-kinase controls alternation of Ī²2 integrin-mediated ligand binding with integrin detachment
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