Ecological Aspects of Selenosis on Rangelands

Plants containing high concentrations of selenium (Se) have long been recognized for their toxic effects on animals. Marco Polo, traveling in China in 1295, was probably describing signs of Se poisoning when he wrote that the hooves of his livestock became swollen and dropped off when they grazed plants growing in certain areas (Rosenfeld and Beath 1964). Loss of hair and nails in humans, presumably suffering from chronic Se ingestion was described in Colombia by Father Simon Pedro in 1560 [National Research Council (NRC) 1976, 1983]. Guang-Qi (1987) has also described and illustrated chronic selenium toxicosis in some Chinese peopl

Chapter G: Selenium poisoning in livestock

Selenium in certain soils may be taken up by plants in amounts sufficient to make forage toxic to animals. Seleniterous forage can be found in semiarid areas on soils typically derived from Cretaceous geologic material in the Western United States and Canada. Intoxication of livestock by seleniterous plants has been classified as acute or chronic. Acute poisoning results from consuming plants containing high selenium concentrations. Chronic selenium poisoning has been described in two forms: alkali disease and blind staggers. Alkali disease results from prolonged ingestion of plants containing, 5-40 ppm selenium in inorganic or organic forms. Alkali disease causes loss or hair, lameness, weight loss and probably reduces reproductive efficiency . Blind staggers is said to result from the consumption or selenium indicator plants. These plants, in contrast to the nonaccumulators, contain selenium in water soluble, nonprotein forms. Blind staggers causes animals to wander, walk in circles, and to have difficulty in swallowing; in addition, it may cause blindness. Information is presented that questions the attribution of blind staggers to selenium toxicosis

Reproductive response of ewes fed alfalfa pellets containing sodium selenate or astragalus bisulcatus as a selenium source

Selenium fed to open cycling ewes in the form of sodium selenate or Astragalus bisulcatus (a selenium accumulator plant) at 24 or 29 ppm selenium, respectively, in alfalfa hay pellets did not alter the estrous cycle length, estrus behavior, progesterone or estrogen profiles, pregnancy rate or outcome of parturition (P>0.05). There was wool loss in some ewes fed seleniferous pellets and the mean whole blood selenium levels were 0.45, 1.3 and 2.4 ppm, respectively, for control, A bisulcatus and sodium selenate; however, ewe condition and appearance remained good. All lambs appeared normal and the number of lambs born and the individual and total lamb weight averages were not significantly (P>0.05) different between treatment groups and control group

Elementary operations for quantum logic with a single trapped two-level cold ion beyond Lamb-Dicke limit

A simple alternative scheme for implementing quantum gates with a single trapped cold two-level ion beyond the Lamb-Dicke (LD) limit is proposed. Basing on the quantum dynamics for the laser-ion interaction described by a generalized Jaynes-Cummings model, one can introduce two kinds of elementary quantum operations i.e., the simple rotation on the bare atomic state, generated by applying a resonant pulse, and the joint operation on the internal and external degrees of the ion, performed by using an off-resonant pulse. Several typical quantum gates, including Hadamard gate, controlled-Z and controlled-NOT gates $etc.$, can thus be implemented exactly by using these elementary operations. The experimental parameters including the LD parameter and the durations of the applied laser pulses, for these implementation are derived analytically and numerically. Neither the LD approximation for the laser-ion interaction nor the auxiliary atomic level is needed in the present scheme.Comment: 5 pages, no figure, to appear in Opt. Com

Selenium in seleniferous environments

Selenium is biologically important because (i) it is essential in animal and possibly plant metabolism, (ii) in many areas diets do not contain sufficient Se to meet animals' needs, and (iii) in other areas it is toxic to animals when it occurrs in high concentrations in soil, water, plants, fly ash, or in aerosols. Animals require 0.05 to 0.1 mg Se/kg in their diets to prevent Se deficiency but suffer Se toxicosis when dietary levels exceed 5 to 15 mg Se/kg. The earth's crustal materials generally contain <0.1 mg Se/kg. Higher concentrations are found in Cretaceous shales. The Se-accumulator plants growing on the seleniferous soils may contain hundreds or even thousands of mg Se/kg. However, the nonaccumulator grasses and forbs seldom accumulate >50 mg Se/kg and more often contain <5 mg Se/kg. Soils and plants may discharge volatile forms of Se into the atmosphere. However, plants may also absorb measurable amounts of gaseous Se from the atmosphere. Anthropogenic activities impact the amount of Se entering our nation's lakes, rivers, and the atmosphere. Combustion of coal and incineration of municipal waste exhaust Se into the environment. In addition, crop-fallow and irrigation practices that allow leaching waters to pass through seleniferous strata prior to intersecting with surface flow, augment the Se levels encountered by plant and animal life

Selenium poisoning in livestock: a review and progress

Selenium in certain soils may be taken up by plants in amounts to render them toxic. Seleniferous forage can be found in most of the western states. Intoxication of livestock by seleniferous plants has been classified as acute and chronic. Acute poisoning results from consumption of plants having high levels of Se; chronic Se poisoning has been described in two forms— alkali disease and blind staggers. Alkali disease is said to result from the consumption of seleniferous grains and grasses, and is manifest by loss of hair, lameness, and loss of weight. Blind staggers is slid to result from the consumption of Se indicator plants and is manifest by wandering, circling, loss of ability to swallow, and blindness. Some research casts doubt on the above classification of Se poisoning. Research using pigs (Sus scrofa domesticus) indicates that the source of Se does not alter the type of lesion or signs of poisoning observed. There are data available that suggest that blind staggers is not related to Se poisoning

Holography from Conformal Field Theory

The locality of bulk physics at distances below the AdS length is one of the remarkable aspects of AdS/CFT duality, and one of the least tested. It requires that the AdS radius be large compared to the Planck length and the string length. In the CFT this implies a large-N expansion and a gap in the spectum of anomalous dimensions. We conjecture that the implication also runs in the other direction, so that any CFT with a planar expansion and a large gap has a local bulk dual. For an abstract CFT we formulate the consistency conditions, most notably crossing symmetry, and show that the conjecture is true in a broad range of CFT's, to first nontrivial order in 1/N^2: any CFT with a gap and a planar expansion is generated via the AdS/CFT dictionary from a local bulk interaction. We establish this result by a counting argument on each side, and also investigate various properties of some explicit solutions.Comment: 49 pages. Minor corrections. Figure and references adde

Yangian symmetry of scattering amplitudes in N=4 super Yang-Mills theory

Tree-level scattering amplitudes in N=4 super Yang-Mills theory have recently been shown to transform covariantly with respect to a 'dual' superconformal symmetry algebra, thus extending the conventional superconformal symmetry algebra psu(2,2|4) of the theory. In this paper we derive the action of the dual superconformal generators in on-shell superspace and extend the dual generators suitably to leave scattering amplitudes invariant. We then study the algebra of standard and dual symmetry generators and show that the inclusion of the dual superconformal generators lifts the psu(2,2|4) symmetry algebra to a Yangian. The non-local Yangian generators acting on amplitudes turn out to be cyclically invariant due to special properties of psu(2,2|4). The representation of the Yangian generators takes the same form as in the case of local operators, suggesting that the Yangian symmetry is an intrinsic property of planar N=4 super Yang-Mills, at least at tree level.Comment: 23 pages, no figures; v2: typos corrected, references added; v3: minor changes, references adde

Comparative toxicity of selenium from seleno-DL-methionine, sodium selenate, and Astragalus bisulcatus in pigs

Selenium is an essential micronutrient, although ingestion in excess in pigs can cause disease conditions including neurological dysfunction and chronic skin and hoof lesions. Controlled feeding trials in growing swine, using the same Se content in feed sources, resulted in higher concentrations (p 0.05) of Se in blood and organs of pigs fed seleno-DL-methionine compared with those receiving Astragalus bisulcatus or sodium selenate. Clinical signs of Se toxicity including neurological signs of paralysis were more severe and occurred sooner in the A. bisulcatus group than in the sodium selenate or seleno-DL-methionine groups. All five pigs fed A. bisulcatus developed neurological signs of paralysis, and in four the signs occurred within 5 days of the start of treatment. Four of five pigs fed sodium selenate also developed paralysis, but this occurred 4 to 21 days after treatment began. The fifth pig in the group developed signs of chronic selenosis. Two of five pigs fed seleno-DL-methionine developed paralysis on 9 and 24 days, respectively, and the remaining three developed chronic selenosis. Selenium fed to pigs in three forms [plant (A. bisulcatus), sodium selenate, or seleno-DL-methionine] resulted in neurological dysfunction and lesions of symmetrical poliomyelomalacia. These were most severe in the A. bisulcatus group, which also had polioencephalomalacia. Although seleno-m-methionine caused the greater increase in tissue and blood Se concentrations, this did not correlate with severity of pathological changes, since animals fed A. bisulcatus developed more severe and disseminated lesions

Review of AdS/CFT Integrability: An Overview

This is the introductory chapter of a review collection on integrability in the context of the AdS/CFT correspondence. In the collection we present an overview of the achievements and the status of this subject as of the year 2010.Comment: 31 pages, v2: reference added, references to other chapters updated, v3: footnote 1 on location of references added, v4: minor changes, references added, accepted for publication in Lett. Math. Phys, v5: minor corrections, links to chapters updated, attached IntAdS.pdf with all chapters in one file, see http://arxiv.org/src/1012.3982/anc/IntAdS.pdf or http://www.phys.ethz.ch/~nbeisert/IntAdS.pd