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 $2\pi/|k|$ of a contact line moving with velocity $v$ is given as $\tau^{-1}(k)=c(v) |k|$. The velocity dependence of $c(v)$ is shown to drastically depend on the dissipation mechanism: we find $c(v)=c(v=0)-2 v$ for the case when the dynamics is governed by microscopic jumps of single molecules at the tip (Blake mechanism), and $c(v)\simeq c(v=0)-4 v$ 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 – 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 Lefebvre’s 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 state’s 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