Acanthocephalan infection and sparganosis in a green tree snake (Dendrelaphis punctulata)     

AG Hill  PW Ladds  DM Spratt 《Australian veterinary journal》2014,92(9):362-364

Acanthocephalan and spargana parasites were identified within a body wall mass during exploratory surgery in a wild green tree snake. Acanthocephalan parasites have not previously been reported in this species. Surgical excision, the treatment of choice, could not be achieved because of the extensive infiltration of the coelomic cavity.  相似文献   

Allelic losses and gains during translocations of a high conservation value fish,Coregonus lavaretus     

Kim Præbel  Colin W. Bean  Jennifer A. Dodd  Elizabeth C. Etheridge  Andrew R.D. Gowans  Rune Knudsen  Alexander A. Lyle  Peter S. Maitland  Ian J. Winfield  Colin E. Adams 《水产资源保护:海洋与淡水生态系统》2021,31(9):2575-2585

1. The use of translocations to establish new or ‘refuge’ populations for species with high conservation value is controversial but widely used in conservation management. One of the risks of this approach is that an establishing population does not adequately capture the genetic diversity of the donor gene pool. This effect, rarely examined, is tested here.
2. In this study the genetic consequences of two conservation translocations after five generations (16 years) of the European whitefish, Coregonus lavaretus, were quantified. Both translocations were made using almost the same genetic groups and thus represent a partly replicated natural study.
3. Analysis of 12 informative microsatellites showed that expected heterozygosity, the mean number of alleles per locus and allelic richness did not differ between donor and translocated populations. There was also no loss of heterozygosity in the translocated populations, nor deviations from Hardy–Weinberg equilibrium expectations, nor signs of linkage disequilibrium.
4. All populations were genetically differentiated but pairwise F_ST values were low, indicating that the magnitude of divergence was small.
5. There was no evidence of inbreeding but there were significant differences in private allelic richness between donor and translocated populations. Of 50 alleles found in the donor population, 16% of the rarer alleles were lost in one translocated population and 8% in the other.
6. Allele loss without a reduction in heterozygosity strongly points to stochastic drift effects having occurred following translocation. The evidence indicates that alleles that were not detected in the donor population have arisen de novo in the translocated populations.
7. It is concluded that conservation translocations comprising even a modest number of propagules can successfully capture a high proportion of genetic variation of the host population, and that reduced genetic variation in the translocated population may be mitigated by the emergence of new variation over short time periods.

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Probing the Local Effects of Magnetic Impurities on Superconductivity     

A Yazdani  BA Jones  CP Lutz  MF Crommie  DM Eigler 《Science (New York, N.Y.)》1997,275(5307):1767-1770

The local effects of isolated magnetic adatoms on the electronic properties of the surface of a superconductor were studied with a low-temperature scanning tunneling microscope. Tunneling spectra obtained near magnetic adsorbates reveal the presence of excitations within the superconductor's energy gap that can be detected over a few atomic diameters around the impurity at the surface. These excitations are locally asymmetric with respect to tunneling of electrons and holes. A model calculation based on the Bogoliubov-de Gennes equations can be used to understand the details of the local tunneling spectra.  相似文献   

Spontaneous formation of macroscopic chiral domains in a fluid smectic phase of achiral molecules     

DR Link  G Natale  R Shao  JE Maclennan  NA Clark  E Korblova  DM Walba 《Science (New York, N.Y.)》1997,278(5345):1924-1927

A smectic liquid-crystal phase made from achiral molecules with bent cores was found to have fluid layers that exhibit two spontaneous symmetry-breaking instabilities: polar molecular orientational ordering about the layer normal and molecular tilt. These instabilities combine to form a chiral layer structure with a handedness that depends on the sign of the tilt. The bulk states are either antiferroelectric-racemic, with the layer polar direction and handedness alternating in sign from layer to layer, or antiferroelectric-chiral, which is of uniform layer handedness. Both states exhibit an electric field-induced transition from antiferroelectric to ferroelectric.  相似文献   

Organic Glasses: A New Class of Photorefractive Materials     

PM Lundquist  R Wortmann  C Geletneky  RJ Twieg  M Jurich  VY Lee  CR Moylan  DM Burland 《Science (New York, N.Y.)》1996,274(5290):1182-1185

The performance of amorphous organic photorefractive (PR) materials in applications such as optical data storage is generally limited by the concentration of active molecules (chromophores) that can be incorporated into the host without forming a crystalline material with poor optical quality. In polymeric PR systems described previously, performance has been limited by the necessity of devoting a large fraction of the material to inert polymer and plasticizing components in order to ensure compositional stability. A new class of organic PR materials composed of multifunctional glass-forming organic chromophores is described that have long-term stability and greatly improved PR properties.  相似文献   

Nanofabrication of Small Copper Clusters on Gold(111) Electrodes by a Scanning Tunneling Microscope     

DM Kolb  R Ullmann  T Will 《Science (New York, N.Y.)》1997,275(5303):1097-1099

The use of scanning tunneling microscopy in an electrochemical environment as a tool for the nanoscale modification of gold electrodes was demonstrated. Small copper clusters, typically two to four atomic layers in height, were precisely positioned on a gold(111) electrode by a process in which copper was first deposited onto the tip of the scanning tunneling microscope, which then acted as a reservoir from which copper could be transferred to the surface during an appropriate approach of the tip to the surface. Tip approach and position were controlled externally by a microprocessor unit, allowing the fabrication of various patterns, cluster arrays, and "conducting wires" in a very flexible and convenient manner.  相似文献   

The bonding electron density in aluminum     

Nakashima PN  Smith AE  Etheridge J  Muddle BC 《Science (New York, N.Y.)》2011,331(6024):1583-1586

Aluminum is considered to approach an "ideal" metal or free electron gas. The valence electrons move freely, as if unaffected by the presence of the metal ions. Therefore, the electron redistribution due to chemical bonding is subtle and has proven extremely difficult to determine. Experimental measurements and ab initio calculations have yielded substantially different results. We applied quantitative convergent-beam electron diffraction to aluminum to provide an experimental determination of the bonding electron distribution. Calculation of the electron distribution based on density functional theory is shown to be in close agreement. Our results yield an accurate quantitative correlation between the anisotropic elastic properties of aluminum and the bonding electron and electrostatic potential distributions.  相似文献   

Factors affecting the performance of granular insecticides applied to field beans     

I. J. Graham-Bryce  J. H. Stevenson  P. Etheridge 《Pest management science》1972,3(6):781-797

Factors influencing the performance of various granular formulations of disulfoton and phorate after foliar application to field beans were investigated by bioassay in controlled environment rooms. Frequent rainfall and high temperature increased activity considerably but humidity had little effect. With disulfoton formulation on pumice rather than fuller's earth, and toxicant concentrations of 7.5% rather than 10% increased toxicity, but effects of formulation were small with phorate. The influence of rainfall and formulation were confirmed in a field experiment. There was evidence for an initial fumigant effect, particularly for phorate, in both laboratory and field experiments. The detailed effects of the various factors at different intervals after applying the granules are discussed in relation to the physical properties of the insecticides and granular carriers. It is suggested that the possibilities of controlling performance by influencing release rates from granules are limited for chemicals such as phorate and disulfoton which are appreciably adsorbed by soil.  相似文献   

Contagious bovine pleuropneumonia produced by aerosols artificially generated from cultures of Mycoplasma mycoides subsp. mycoides     

L C Lloyd  J R Etheridge 《The British veterinary journal》1983,139(4):330-337

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SLIDE AGGLUTINATION TESTS IN THE DIAGNOSIS OF CONTAGIOUS BOVINE PLEUROPNEUMONIA   总被引：1，自引：0，他引：1  

A. W. Turner  J. R. Etheridge 《Australian veterinary journal》1963,39(12):445-451

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