—The recent discovery of herbivores that feed on Ni-hyperaccumulating plants and contain elevated Ni concentrations in their bodies suggests that Ni may be transferred to their predators. We tested this hypothesis using the high-Ni herbivore Melanotrichus boydi and four predator species: the spiders Pholcus phalangioides and Misumena vatia, the mantid Stagmomantis californica and the lacewing C...

Inanga (Galaxias maculatus) are a euryhaline and amphidromous Southern hemisphere fish species inhabiting waters highly contaminated in trace elements such as nickel (Ni). Ni is known to exert its toxic effects on aquatic biota via three key mechanisms: inhibition of respiration, impaired ion regulation, and stimulation of oxidative stress. Inanga acclimated to freshwater (FW), 50% seawater (SW...

This study investigated the effect of reaction time (minutes to months) on the surface coordination environment of Ni sorbed onto pyrophyllite using XAFS. The data suggest the appearance of multinuclear Ni complexes after a reaction time of minutes. As reaction time !>rogresses, these multinuclear Ni complexes increased in size «NNi-Ni 1.4-4.5). Ni-Ni bond distances (2.99-3.03 A) were similar t...

Nymphs of Stenoscepa sp. feed on leaves of the Ni hyperaccumulator Berkheya coddii at serpentine sites in Mpumalanga Province, South Africa. These sites contain Ni hyperaccumulators, Ni accumulators, and plants with Ni concentrations in the normal range. We conducted studies to: (i) determine the whole-body metal concentration of nymphs (including those starved to empty their guts); (ii) compar...

The purpose of this manuscript is to prov\de a survey to basic notions and results concerning a theory of average case complexity initiated by Leonid Levin. This survey is mainly bas~d on Levin's paper Avet:age Case Complete Problems [L], and expositions of it due to Johnson [J], Gurevich [GJ, and Gurevich and McCauley [GMc]. Further developments due to Gurevich [GJ and others are also briefly ...

Let {S′Ni | i ∈ IN} represent a set consequence operators defined on the language Λ, where each member of {S′Ni | i ∈ IN} corresponds to a science-community physical theory. It is shown that there exists a hyperfinite ultralogic U ∈ ∗Cf defined on all internal subsets of Λ such that U 6 = U, and, for each i ∈ IN, S Ni ( ∗Ni) = U( ∗Ni). For each internal Y ⊂ Λ, ⋃ { S Ni (Y ) | i ∈ IN} ⊂ U(Y ) ⊂ ...

Spin-dependent transport of nonequilibrium holes in ferromagnetic thin films and trilayers is investigated using ballistic hole magnetic microscopy. For Co, the hole attenuation length is short and increases from 6 to 10 A in the energy range 0.8 to 2 eV. The hole transmission of a Ni(81)Fe(19)/Au/Co trilayer is clearly spin dependent, resulting in a surprisingly large current change by a facto...

The conductor of n positive integer numbers a l,a2, ... ,an' whose greatest coII1mon divisor is equal'to I, is'defmed as the th.e minimal K, such that for every m ~K , the equation a1x 1+a2X 2+ ... +an Xn=m, h!ls a solution over the nOI}negative integers. In this notewe give a polYIlomial aigorithm computing'a close bound ~ for the conductor K o( n given positive integers, when n is fixed. The ...

Ni/Co multilayers grown by molecular beam epitaxy are found to exhibit a magnetoresistance AR/R at liquid helium temperature as large as 8.2%, with saturation fields AH-22 Oe and a sensitivity (AR/R)/(2AH)=O. 19% Oe-‘. The highest room temperature sensitivity obtained to date in this system is 0.18% Oe-’ and at 4.2 K is 0.29% Oe-‘. This demonstrates that high values of the sensitivity can be ac...