915 research outputs found
REFORMULATED 4-AMINOPYRIDINE BAITS COST-EFFECTIVELY REDUCE BLACKBIRD DAMAGE TO RIPENING CORNFIELDS
In 1984 4-aminopyridine baits, stabilized with hydrochloric acid, were appraised in ripening cornfields being attacked by blackbirds on the Sand Lake National Wildlife Refuge., South Dakota. In 1982, i t had been discovered that 4-aminopyridine, the active agent in commercial Avitrol® baits for crop protection rapidly vaporized at summer storage and field baiting temperatures. In July, baiting lanes were created in 12 cornfields by destroying every 55th row. In August after a 3-day pretreatment period, fields were baited with Avitrol® FC Corn Chops-99 for a 2-week period when corn was most vulnerable to damage. Bait was applied from baiting lanes at the rate of 1 Ib/acre of field with an electric seeder mounted on an all-terrain cycle. Rebaitings were made at half the initial rate; 0 to 3 rebaitings were needed, largely because of depletion of baits by insects and rodents. An insecticidal pretreatment, 5% carbaryl pellets, did not significantly lower the rate of bait depletion. Blackbird damage was 87% less (P=\u3c0.001) during the baited than the pretreatment period (19 vs 142 bu of corn lost per day). From 2,000 to 17,000 blackbirds, mostly red-winged and yellow-headed blackbirds, were observed in test fields. An estimated 825 dead or affected blackbirds and 1 mourning dove were observed or collected in test fields. Application of baits on baiting lanes with a seeder mounted on a cycle proved both economical and efficient . About 100 acres/h were baited at an estimated cost of \u3c15 cents/acre/application. About 1 spent for bait and loss of corn yield in baiting lanes. Growers would have saved about $400/h for time spent in creating lanes and baiting
The rigid syntomic ring spectrum
The aim of this paper is to show that Besser syntomic cohomology is
representable by a rational ring spectrum in the motivic homotopical sense. In
fact, extending previous constructions, we exhibit a simple representability
criterion and we apply it to several cohomologies in order to get our central
result. This theorem gives new results for syntomic cohomology such as
h-descent and the compatibility of cycle classes with Gysin morphisms. Along
the way, we prove that motivic ring spectra induces a complete Bloch-Ogus
cohomological formalism and even more. Finally, following a general motivic
homotopical philosophy, we exhibit a natural notion of syntomic coefficients.Comment: Final version to appear in the Journal de l'institut des
Math\'ematiques de Jussieu. Many typos have been corrected and the exposition
has been improved according to the suggestions of the referees: we thank them
a lot
STARLING CONTROL IN LIVESTOCK FEEDING AREAS
The Denver Wildlife Research Center has been investigating methods to combat starling (Sturnus vulgaris) problems at livestock feeding areas since 1960. A variety of chemicals, baits, and methods of bait placement have been tested. This paper summarizes these investigations.
CHEMICALS TESTED About 500 chemicals have been screened for toxic and stupefacient effects on starlings. Although several chemicals have been found that immobilize starlings in the laboratory, they have been largely ineffective in the field; most starlings regurgitate the treated baits, and seldom have substantial numbers been affected. Of the toxicants screened, four compounds, TEPP, DRC-632, DRC-1327, and DRC-1339, have shown enough activity as control agents for starlings to warrant intensive investigation in the laboratory and the field
LATE-SUMMER FEEDING PATTERNS OF RED-WINGED BLACKBIRDS IN A SUNFLOWER-GROWING AREA OF NORTH DAKOTA
During August and September in 1977 and 1978, we monitored the feeding patterns of radio-equipped, male red-winged blackbirds (Agelaius phoeniceus) and associated blackbird flocks in the vicinity of Fuller’s Lake Waterfowl Production Area in Steele County in east-central North Dakota. Fuller’s Lake, a cattail marsh of about 1,000 acres (405 ha), serves as the main roosting area for a blackbird assemblage that, for the past seven years in late summer, has numbered from 100,000 in wet years to more than 750,000 in dry years. Sunflower is an important crop in the Fuller’s Lake area, being grown on about 20 percent of cropland. Wheat and barley are other major crops, grown on about 40 percent of the cropland. Corn is grown on less than 1 percent of the cropland, but the number of quarter-section (160-acre, 65 ha), irrigated cornfields increased in the area from two in 1977 to eight in 1978. The Fuller’s Lake area lies on the eastern edge of the North Dakota Drift Plains and is poorly drained, with as many as a dozen water basins per square mile. This combination of a large roosting marsh and numerous satellite roosting and loafing marshes, intermingled with sunflower fields, has created optimum conditions for blackbirds to damage some sunflower fields. Damage was estimated at 23.6 percent of the sunflower crop in a 28-section area surrounding Fuller’s Lake in 1972 (Besser and Guarino 1977), when little control effort was expended. Experiments were conducted with 4-aminopyridine baits as a frightening agent to protect sunflowers from blackbird damage in a 7-township (3-county) study area in the Fuller’s Lake area in 1977 and 1978. In 1977, 31 of the most heavily damaged fields were baited with Avitrol® FC-Corn Chops 99S (Henne 1978), but in 1978 only five were baited (Henne et al. 1979). These experiments afforded us an excellent opportunity to monitor the feeding patterns of blackbirds frightened from ripening sunflower fields as well as undisturbed birds. In some instances, when a feeding pattern had been established by a flock in an untreated ripening sunflower field, we frightened the flock from the field by mechanical means. This paper presents the major findings of this 2-year study
Test-retest reliability of temporal and spatial gait characteristics measured with an instrumented walkway system (GAITRite(®))
BACKGROUND: The purpose of this study was to determine the test-retest reliability of temporal and spatial gait measurements over a one-week period as measured using an instrumented walkway system (GAITRite(®)). METHODS: Subjects were tested on two occasions one week apart. Measurements were made at preferred and fast walking speeds using the GAITRite(® )system. Measurements tested included walking speed, step length, stride length, base of support, step time, stride time, swing time, stance time, single and double support times, and toe in-toe out angle. RESULTS: Twenty-one healthy subjects participated in this study. The group consisted of 12 men and 9 women, with an average age of 34 years (range: 19 – 59 years). At preferred walking speed, all gait measurements had ICC's of 0.92 and higher, except base of support which had an ICC of 0.80. At fast walking speed all gait measurements had ICC's above 0.89 except base of support (ICC = 0.79), CONCLUSIONS: Spatial-temporal gait measurements demonstrate good to excellent test-retest reliability over a one-week time span
Laser structuring of NMC 811 high energy electrodes in battery production for enhancing the electrochemical performance for xEV energy storage systems
Layered oxide cathodes, especially thick-film electrodes like lithium nickel manganese cobalt oxide, NMC, are under continuously investigation to meet the ambitious requirements, e.g. 700 Wh/l, for future Li-ion batteries in electric drive applications. The objective of the most current studies is to reduce the Co content with a concurrent increasing Ni-content in the NMC cathodes such as NMC 811 [1]. It must not leave the fact out of consideration, that NMC cathodes suffer from low high rate capability and corresponding low capacity retention at high C-rates. In particular, the negative impact is even higher for thick-film high energy cathodes. To counteract the negative effect, high repetition ultrafast laser ablation is applied to create appropriate 3D electrode designs [2]. New Li+-diffusion pathways, applied by the laser structuring process, shell enhance electrolyte wettability and reduce overpotentials at high C-rates. It is attempted to integrate the laser structuring into a continuous roll-to-roll electrode production process. In this way, the positive properties achieved through 3D structuring can also be obtained for Li-ion batteries that are produced on a large scale. By using this novel production technology, future NMC batteries can be produced with improved performance characteristics for xEV applications. Furthermore, this technology can also be applied for other generation 3b battery cells. This work is performed under the frame of the RealLi! project, in which the following aspects are covered:
a) Development of thick film NMC811 electrodes with high areal capacity
b) Passivation approach to improve cycle stability and lifetime
c) Cell Assembly and electrochemical characterization
d) Holistic evaluation of the potential environmental impact of the NMC811 cells via life cycle assessment
e) An experimentally validated electrochemical model to describe electrode structures and their optimization.
f) Improved electrochemical performance of NMC811 electrodes on a laboratory scale by using 3D laser structuring.
g) Scale up of the 3D laser structuring process and corresponding improved electrochemical performance of NMC811 electrodes in pouch cell format by using 3D laser ablation
Applications and limitations of electron correlation microscopy to study relaxation dynamics in supercooled liquids
Electron correlation microscopy (ECM) is a way to measure structural relaxation times, τ, of liquids with nanometer-scale spatial resolution using coherent electron scattering equivalent of photon correlation spectroscopy. We have applied ECM with a 3.5 nm diameter probe to Pt57.5Cu14.7Ni5.3P22.5 amorphous nanorods and Pd40Ni40P20 bulk metallic glass (BMG) heated inside the STEM into the supercooled liquid region. These data demonstrate that the ECM technique is limited by the characteristics of the time series, which must be at least 40τ to obtain a well-converged correlation function g2(t), and the time per frame, which must be less than 0.1τ to obtain sufficient sampling. A high-speed direct electron camera enables fast acquisition and affords reliable g2(t) data even with low signal per frame
A macroinvertebrate assessment of Ozark streams located in lead–zinc mining areas of the Viburnum Trend in southeastern Missouri, USA
The Viburnum Trend lead–zinc mining subdistrict is located in the southeast Missouri portion of the Ozark Plateau. In 2003 and 2004, we assessed the ecological effects of mining in several watersheds in the region. We included macroinvertebrate surveys, habitat assessments, and analysis of metals in sediment, pore water, and aquatic biota. Macroinvertebrates were sampled at 21 sites to determine aquatic life impairment status (full, partial, or nonsupport) and relative biotic condition scores. Macroinvertebrate biotic condition scores were significantly correlated with cadmium, nickel, lead, zinc, and specific conductance in 2003 (r = −0.61 to −0.68) and with cadmium, lead, and pore water toxic units in 2004 (r = −0.55 to −0.57). Reference sites were fully supporting of aquatic life and had the lowest metals concentrations and among the highest biotic condition scores in both years. Sites directly downstream from mining and related activities were partially supporting, with biotic condition scores 10% to 58% lower than reference sites. Sites located greater distances downstream from mining activities had intermediate scores and concentrations of metals. Results indicate that elevated concentrations of metals originating from mining activities were the underlying cause of aquatic life impairment in several of the streams studied. There was a general concurrence among the adversely affected sites in how the various indicators responded to the mining activities during the overall study
Coupling biochemistry and mechanics in cell adhesion: a model for inhomogeneous stress fiber contraction
Biochemistry and mechanics are closely coupled in cell adhesion. At sites of
cell-matrix adhesion, mechanical force triggers signaling through the
Rho-pathway, which leads to structural reinforcement and increased
contractility in the actin cytoskeleton. The resulting force acts back to the
sites of adhesion, resulting in a positive feedback loop for mature adhesion.
Here we model this biochemical-mechanical feedback loop for the special case
when the actin cytoskeleton is organized in stress fibers, which are
contractile bundles of actin filaments. Activation of myosin II molecular
motors through the Rho-pathway is described by a system of reaction-diffusion
equations, which are coupled into a viscoelastic model for a contractile actin
bundle. We find strong spatial gradients in the activation of contractility and
in the corresponding deformation pattern of the stress fiber, in good agreement
with experimental findings.Comment: Revtex, 35 pages, 13 Postscript figures included, in press with New
Journal of Physics, Special Issue on The Physics of the Cytoskeleto
Phase transitions for -adic Potts model on the Cayley tree of order three
In the present paper, we study a phase transition problem for the -state
-adic Potts model over the Cayley tree of order three. We consider a more
general notion of -adic Gibbs measure which depends on parameter
\rho\in\bq_p. Such a measure is called {\it generalized -adic quasi Gibbs
measure}. When equals to -adic exponent, then it coincides with the
-adic Gibbs measure. When , then it coincides with -adic quasi
Gibbs measure. Therefore, we investigate two regimes with respect to the value
of . Namely, in the first regime, one takes for some
J\in\bq_p, in the second one . In each regime, we first find
conditions for the existence of generalized -adic quasi Gibbs measures.
Furthermore, in the first regime, we establish the existence of the phase
transition under some conditions. In the second regime, when we prove the existence of a quasi phase transition. It turns out that
if and \sqrt{-3}\in\bq_p, then one finds the existence
of the strong phase transition.Comment: 27 page
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