2,629 research outputs found
New Species, Subgenus and Records of Bactrocera Macquart from the South Pacific (Diptera: Tephritidae: Dacinae)
ABSTRACT Bactrocera (Bulladacus) subgen.nov. is described to include nine species of Asian and Pacific Dacinae. B. (Afrodacus) grandistylus sp.nov., B. (Bulladacus) gnetum sp.nov. and B. (Notodacus) paraxanthodes sp.nov. are described and illustrated, the latter being closely related to B. xanthodes (Broun), an economic species with which it has been confused. B. (Bactrocera) passiflorae (Froggatt) and B. (Bulladacus) aenigmatica (Malloch) are revised and a new colour form of the former illustrated, while the male of the latter is described and illustrated for the first time
Two new species of dacinae (diptera: trypetidae) from New Britain
i Two new species, Asiadacus triangularis and Asiadacus nigrescensare described and figured
Resonance line-profile calculations based on hydrodynamical models of cataclysmic variable winds
We present synthetic line profiles as predicted by the models of 2-D line-
driven disk winds due to Proga, Stone & Drew. We compare the model line
profiles with HST observations of the cataclysmic variable IX Vel. The model
wind consists of a slow outflow that is bounded on the polar side by a fast
stream. We find that these two components of the wind produce distinct spectral
features. The fast stream produces profiles which show features consistent with
observations. These include the appearance of the P-Cygni shape for a range of
inclinations, the location of the maximum depth of the absorption component at
velocities less than the terminal velocity, and the transition from absorption
to emission with increasing inclination. However the model profiles have too
little absorption or emission equivalent width. This quantitative difference
between our models and observations is not a surprise because the line-driven
wind models predict a mass loss rate that is lower than the rate required by
the observations. We note that the model profiles exhibit a double-humped
structure near the line center which is not echoed in observations. We identify
this structure with a non-negligible redshifted absorption which is formed in
the slow component of the wind where the rotational velocity dominates over
expansion velocity. We conclude that the next generation of disk wind models,
developed for application to CVs, needs to yield stronger wind driving out to
larger disk radii than do the present models.Comment: LaTeX, 19 pages, to appear in Ap
Alimentary Tract Bacteria Isolated and Identified with API-20E and Molecular Cloning Techniques from Australian Tropical Fruit Flies, Bactrocera cacuminata and B. tryoni
Bacteria were isolated from the crop and midgut of field collected Bactrocera cacuminata (Hering) and Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Two methods were used, firstly isolation onto two types of bacteriological culture media (PYEA and TSA) and identification using the API-20E diagnostic kit, and secondly, analysis of samples using the 16S rRNA gene molecular diagnostic method. Using the API-20E method, 10 genera and 17 species of bacteria in the family Enterobacteriaceae were identified from cultures growing on the nutrient agar. The dominant species in both the crop and midgut were Citrobacter freundii, Enterobacter cloacae and Klebsiella oxytoca. Providencia rettgeri, Klebsiella pneumoniae ssp ozaenae and Serratia marcescens were isolated from B. tryoni only. Using the molecular cloning technique that is based on 16S rRNA gene sequences, five bacteria classes were dignosed — Alpha-, Beta-, Gamma- and Delta- Proteobacteria and Firmicutes — including five families, Leuconostocaceae, Enterococcaceae, Acetobacteriaceae, Comamonadaceae and Enterobacteriaceae. The bacteria affiliated with Firmicutes were found mainly in the crop while the Gammaproteobacteria, especially the family Enterobacteriaceae, was dominant in the midgut. This paper presents results from the first known application of molecular cloning techniques to study bacteria within tephritid species and the first record of Firmicutes bacteria in these flies
Colossal magnon-phonon coupling in multiferroic EuYMnO
We report the spectra of magnetically induced electric dipole absorption in
EuYMnO from temperature dependent far infrared
spectroscopy (10-250 cm). These spectra, which occur only in the
polarization, consist of two relatively narrow electromagnon features that
onset at K and a broad absorption band that persists to
temperatures well above K. The observed excitations account for the
step up of the static dielectric constant in the ferroelectric phase. The
electromagnon at 80 cm is observed to be strongly coupled to the nearby
lowest optical phonon which transfers more than 1/2 of its spectral weight to
the magnon. We attribute the origin of the broad background absorption to the
two magnon emission decay process of the phonon.Comment: 4 pages, 3 figure
Limits on the Superconducting Order Parameter in NdFeAsOF from Scanning SQUID Microscopy
Identifying the symmetry of the superconducting order parameter in the
recently-discovered ferro-oxypnictide family of superconductors,
RFeAsOF, where is a rare earth, is a high priority. Many of
the proposed order parameters have internal phase shifts, like the d-wave
order found in the cuprates, which would result in direction-dependent phase
shifts in tunnelling. In dense polycrystalline samples, these phase shifts in
turn would result in spontaneous orbital currents and magnetization in the
superconducting state. We perform scanning SQUID microscopy on a dense
polycrystalline sample of \NdFeAsOF with K and find
no such spontaneous currents, ruling out many of the proposed order parameters.Comment: 10 pages, 5 figures; to appear in JPS
Photoinduced superconducting nanowires in Gd-Ba-Cu-O films
We report the fabrication of high Tc superconducting wires by photodoping a
GdBa2Cu3O{6.5} thin film. An optical near-field probe was used to locally
excite carriers in the system at room temperature. Trapping of the
photogenerated electrons define a confining potential for the conducting holes
in the CuO planes. Spatially resolved reflectance measurements show the
photogenerated nanowires to be ~ 250 nm wide. Electron diffusion, before
electron capture, is believed to be responsible for the observed width of the
wires.Comment: 8 pages, 3 figures Submitted to Appl. Phys. Let
Direct observation of the flux-line vortex glass phase in a type II superconductor
The order of the vortex state in La_{1.9} Sr_{0.1} CuO_{4} is probed using
muon spin rotation and small-angle neutron scattering. A transition from a
Bragg glass to a vortex glass is observed, where the latter is composed of
disordered vortex lines. In the vicinity of the transition the microscopic
behavior reflects a delicate interplay of thermally-induced and pinning-induced
disorder.Comment: 14 pages, 4 colour figures include
Multiple mating by females of two Bactrocera species (Diptera: Tephritidae: Dacinae)
Abstract Multiple mating was investigated in two tephritid species when females were under minimal male pressure because they were each confined with a single male in cages 20r20r20 cm and observed daily until they died. Laboratory-reared females of Bactrocera cucumis (French) lived up to 274 days and refractory periods averaged 59-63 days. However, the distribution of matings among B. cucumis females was not significantly different to that expected by chance. Wild females of Bactrocera cacuminata (Hering) reared from field-collected fruits of Solanum mauritianum Scopoli lived for up to 134 days and mated up to three times with refractory periods between matings averaging 27-39 days. The distribution of the number of matings among females of B. cacuminata was non-random because of the high proportion of non-maters (50%); but, when only females mating more than once were considered, there was no significant departure from random expectation
Muons as Local Probes of Three-body Correlations in the Mixed State of Type-II Superconductors
The vortex glass state formed by magnetic flux lines in a type-II
superconductor is shown to possess non-trivial three-body correlations. While
such correlations are usually difficult to measure in glassy systems, the
magnetic fields associated with the flux vortices allow us to probe these via
muon-spin rotation measurements of the local field distribution. We show via
numerical simulations and analytic calculations that these observations provide
detailed microscopic insight into the local order of the vortex glass and more
generally validate a theoretical framework for correlations in glassy systems.Comment: 4+ pages, high-quality figures available on reques
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