3,090 research outputs found
Alien Registration- Stoddard, Evangeline S. (Rockland, Knox County)
https://digitalmaine.com/alien_docs/14881/thumbnail.jp
Review of \u3ci\u3eSpatial Organization: The Geographer\u27s View of the World\u3c/i\u3e by Ronald Abler, John S. Adams, and Peter Gould
Most introductory textbooks in geography are content-oriented, some pay lip service to basic concepts in geography, and still others are like tombstones conveying concepts and content of a bygone era. Abler, Adams and Gould have presented an introductory text that is rich in concepts, is rooted in contemporary scientific thinking, and conveys a dynamic, futuristic view of geography. The basic thrust in the book is the circularly causal relationships between spatial structure and spatial processes. Geographers with a lands-and-peoples view of geography will be disappointed
Mind your B's and R's: bacterial chemotaxis, signal transduction and protein recognition
AbstractThe crystal structures of two key regulators of the bacterial chemotaxis pathway (CheR and CheB) have been determined. These studies add further detail to the growing picture of signal transduction and attenuation in the bacterial chemotaxis pathway. The recently determined structure of the methyltransferase CheR bound to a peptide of its target receptor, provides a structural model for intermolecular receptor modification during signaling
Fecal Bacteria Survival and Infiltration through a Shallow Agricultural Soil: Timing and Tillage Effects
Human and livestock exposure to fecal pathogens via contaminated surface or groundwater is an important water quality concern for soils receiving animal wastes. The effects of manure application timing (spring or fall application) and soil management (no-tillage or conservation tillage) on fecal bacteria infiltration through shallow karst soils in central Kentucky (the Bluegrass region) have not been evaluated. We performed a field experiment to measure fecal coliforms and fecal streptococci in leachate from dairy manure-amended no-tillage and conservation tillage soils. Manure significantly increased fecal bacteria in leachate compared with unmanured treatments. After manure application, the leachate that collected in zero-tension lysimeters 90 cm below the soil surface contained up to 6 Ă 104fecal coliforms/100 mL and generally exceeded 3 Ă 103 fecal coliforms/100 mL. Neither the timing nor the tillage method significantly affected fecal coliform concentrations in leachate. Fecal bacteria in leachate declined to nondetectable levels within 60 d of manure application. In the well structured soil used in this experiment, fecal bacteria moved below the crop root zone whenever there was rainfall of sufficient duration or intensity to cause flow after manure application. Manure application to no-tillage soil in spring did not accelerate water contamination by fecal coliforms relative to fall manure applications. No-tillage did not accelerate water contamination by fecal coliforms relative to tilled soils. The potential for groundwater contamination depended on soil structure and water flow more than on fecal bacteria survival at the soil surface
Efficiency and regulation of gasoline electric generator
Citation: Carlson, Torje S., Stoddard, Albert D., and Dow, Jay L. Efficiency and regulation of gasoline electric generator. Senior thesis, Kansas State Agricultural College, 1906.Morse Department of Special CollectionsIntroduction: The dynamo tested is a 1.5 K.W. machine generating 115 volts at a speed of 1850 R.P.M. and is short shunt compound wound. It is constructed so as to require little care, having self oiling ring bearings and brushes that do not require shifting with increase of load. The terminal block on the side of the machine is arranged so simply that no mistake could be made in making the connections. External Characteristic. The curve following shows the external characteristic of the dynamo. In obtaining the data for this curve the dynamo was run at constant speed. The rheostat in the shunt field was adjusted so that a voltmeter placed across the terminals reads 110 volts when the dynamo is running without load. The position of the rheostat arm is not changed during the test. A variable resistance and an ammeter are placed in the external circuit. The resistance is decreased, thus increasing the load until the limit of the machine is reached. Readings are taken simultaneously of line amperes and terminal volts for a number of intermediate points. This data is plotted with terminal volts as ordinates and line amperes as abscissas. The object of compounding a dynamo is to maintain a constant voltage at some point on the circuit. The voltage of a shunt dynamo gradually falls as the load increases, therefore in order to maintain a constant potential regulation of the rheostat would be necessary. By compounding the regulation is automatic and no adjustment of the rheostat is necessary
Fertilizer, Tillage, and Dairy Manure Contributions to Nitrate and Herbicide Leaching
Few studies have examined the water quality impact of manure use in no-tillage systems. A lysimeter study in continuous corn (Zea mays L.) was performed on Maury silt loam (fine, mixed, semiactive, mesic Typic Paleudalf) to evaluate the effect(s) of tillage (no-till [NT] and chisel-disk [CD]), nitrogen fertilizer rate (0 and 168 kg N haâ1), and dairy manure application timing (none, spring, fall, or fall plus spring) on NO3âN, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), and alachlor [2-chloro-2â˛-6â˛-diethyl-N-(methoxymethyl)acetanilide] concentrations in leachate collected at a 90-cm depth. Herbicides were highest immediately after application, declining to less than 4 Îźg Lâ1 in about two months. Manure and manure timing by tillage interactions had little effect on leachate herbicides; rather, the data suggest that macropores rapidly transmitted atrazine and alachlor through the soil. Tillage usually did not significantly affect leachate NO3âN, but no-tillage tended to cause higher NO3âN. Manuring caused higher NO3âN concentrations; spring manuring had more impact than fall, but fall manure contained about 78% of the N found in spring manure. Nitrate under spring âonly fertilizerâ treatment exceeded 10 mg Lâ138% of the time, compared with 15% for spring only manure treatment. After three years, manured soil leachate NO3âN exceeded that for soil receiving only N fertilizer. Soil profile (90 cm) NO3âN after corn harvest exceeding 22 kg N haâ1 was associated with winter leachate NO3âN greater than 10 mg N Lâ1 Manure can be used effectively in conservation tillage systems on this and similar soils. Accounting for all N inputs, including previous manure applications, will be important
Infiltration of Fecal Bacteria Through Soils: Timing and Tillage Effects
Land-applying animal wastes potentially exposes humans and animals to fecal pathogens, either by direct contact with soil and produce, or via ground water contamination. Some of these organisms are Salmonella, certain pathogenic Escherichia coli strains, protozoa such as Cryptosporidium and Giardia, and enteric viruses. Whether soil adequately filters these pathogens before they reach ground water depends on the interaction of porosity, texture, depth, water content, rainfall intensity and duration, and soil management
Fertilizer, Tillage, and Dairy Manure Contributions to Nitrate and Herbicide Leaching
Few studies have examined the water quality impact of manure use in no-tillage systems. A lysimeter study in continuous corn (Zea mays L.) was performed on Maury silt loam (fine, mixed, semiactive, mesic Typic Paleudalf) to evaluate the effect(s) of tillage (no-till [NT] and chisel-disk [CD]), nitrogen fertilizer rate (0 and 168 kg N haâ1), and dairy manure application timing (none, spring, fall, or fall plus spring) on NO3âN, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), and alachlor [2-chloro-2â˛-6â˛-diethyl-N-(methoxymethyl)acetanilide] concentrations in leachate collected at a 90-cm depth. Herbicides were highest immediately after application, declining to less than 4 Îźg Lâ1 in about two months. Manure and manure timing by tillage interactions had little effect on leachate herbicides; rather, the data suggest that macropores rapidly transmitted atrazine and alachlor through the soil. Tillage usually did not significantly affect leachate NO3âN, but no-tillage tended to cause higher NO3âN. Manuring caused higher NO3âN concentrations; spring manuring had more impact than fall, but fall manure contained about 78% of the N found in spring manure. Nitrate under spring âonly fertilizerâ treatment exceeded 10 mg Lâ138% of the time, compared with 15% for spring only manure treatment. After three years, manured soil leachate NO3âN exceeded that for soil receiving only N fertilizer. Soil profile (90 cm) NO3âN after corn harvest exceeding 22 kg N haâ1 was associated with winter leachate NO3âN greater than 10 mg N Lâ1 Manure can be used effectively in conservation tillage systems on this and similar soils. Accounting for all N inputs, including previous manure applications, will be important
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