158 research outputs found
Nocturnal colony attendance by common guillemots Uria aalge at colony in Shetland during the pre-breeding season
No abstract available
Nocturnal colony attendance by common guillemots Uria aalge at colony in Shetland during the pre-breeding season
No abstract available
Salt- and sodium-affected soils
This publication is designed to help identify salt- and
sodium-affected soils, the salt or sodium sources, how
to take soil and water samples, how to reduce the harmful
effects of salts and sodium and where to get advice
in making reclamation and management decisions for
each situation.
Salt- and sodium-affected soils, and waters used for
irrigation, present a complex combination of problems
and possible solutions. It is not the intent here to cover
all technical aspects or possible treatment approaches
available, but rather to give a simplified overview of
what should be considered in diagnosing and managing
salt- and sodium-affected soils and irrigation waters.
Since summarizing the effects of salt and sodium on
soils and plants is difficult without using the appropriate
terminology, a glossary is included
Identification and impact of excess soil potassium on crop and livestock nutrition
Several soils have been identified in the
Intermountain West which contain excessive amounts of
extractable potassium (K). A "normal" ammonium acetate
extractable potassium level may be from 200 to 500 parts
per million (ppm), while the high potassium soils contain
1,000 to over 7,000 ppm. Initial observation of crops
grown on these soils continually showed poor crop yield,
general chlorosis and failure to respond to fertilizer
additions.
While not widely reported in the literature, these soils
have been identified at sites in Idaho, Montana, Oregon,
Utah and Wyoming. Their discovery suggests a need to
further explore the distribution and origin of high
extractable K soils. We may also be able to define steps
to improve crop and livestock productivity on the sites.
This paper presents what we know about excess-K soils and
outlines current efforts to determine their origin,
chemistry and impacts on crops and livestock
Dissipation in Dynamics of a Moving Contact Line
The dynamics of the deformations of a moving contact line is studied assuming
two different dissipation mechanisms. It is shown that the characteristic
relaxation time for a deformation of wavelength of a contact line
moving with velocity is given as . The velocity
dependence of is shown to drastically depend on the dissipation
mechanism: we find for the case when the dynamics is governed
by microscopic jumps of single molecules at the tip (Blake mechanism), and
when viscous hydrodynamic losses inside the moving
liquid wedge dominate (de Gennes mechanism). We thus suggest that the debated
dominant dissipation mechanism can be experimentally determined using
relaxation measurements similar to the Ondarcuhu-Veyssie experiment [T.
Ondarcuhu and M. Veyssie, Nature {\bf 352}, 418 (1991)].Comment: REVTEX 8 pages, 9 PS figure
Roughening Transition in a Moving Contact Line
The dynamics of the deformations of a moving contact line on a disordered
substrate is formulated, taking into account both local and hydrodynamic
dissipation mechanisms. It is shown that both the coating transition in contact
lines receding at relatively high velocities, and the pinning transition for
slowly moving contact lines, can be understood in a unified framework as
roughening transitions in the contact line. We propose a phase diagram for the
system in which the phase boundaries corresponding to the coating transition
and the pinning transition meet at a junction point, and suggest that for
sufficiently strong disorder a receding contact line will leave a
Landau--Levich film immediately after depinning. This effect may be relevant to
a recent experimental observation in a liquid Helium contact line on a Cesium
substrate [C. Guthmann, R. Gombrowicz, V. Repain, and E. Rolley, Phys. Rev.
Lett. {\bf 80}, 2865 (1998)].Comment: 16 pages, 6 encapsulated figure
On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes
The sensitivity of a search for sources of TeV neutrinos can be improved by
grouping potential sources together into generic classes in a procedure that is
known as source stacking. In this paper, we define catalogs of Active Galactic
Nuclei (AGN) and use them to perform a source stacking analysis. The grouping
of AGN into classes is done in two steps: first, AGN classes are defined, then,
sources to be stacked are selected assuming that a potential neutrino flux is
linearly correlated with the photon luminosity in a certain energy band (radio,
IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on neutrino
production in AGN, this correlation is motivated by hadronic AGN models, as
briefly reviewed in this paper.
The source stacking search for neutrinos from generic AGN classes is
illustrated using the data collected by the AMANDA-II high energy neutrino
detector during the year 2000. No significant excess for any of the suggested
groups was found.Comment: 43 pages, 12 figures, accepted by Astroparticle Physic
Spatializing the Ecological Leviathan: Territorial Strategies and the Production of Regional Natures
This paper explores a dual absence â the absence of the state within contemporary geographical analyses of nature; and the absence of nature within contemporary explorations of state power. We argue that the modern state continues to play a crucial role in framing social interactions with nature, while nature is still vital to states within their realization of different forms of material and ideological power. In order to reconnect analyses of the state and nature, this paper combines work on the production of nature and state strategy with Lefebvreâs recently translated writings on state space and territory. By focusing on the production of territory (or state space), we explore the interaction of the state and nature in the context of the political management of social and ecological space. We unravel the spatial entanglements of the state and nature through an analysis of the British stateâs territorial strategies within the West Midlands region. By considering three key historical periods within the history of the West Mid-lands we reveal how the emergence of the regional space called the West Midlands is a product of the ongoing spatial dialectics of state and nature therein
Behavior of humpback whales, Megaptera novaeangliae (Cetacea: Balaenopteridae): comparisons between two coastal areas of Brazil
Bio-analytical Assay Methods used in Therapeutic Drug Monitoring of Antiretroviral Drugs-A Review
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