3,636 research outputs found
The Influence of Host Condition on Post First Instar Development of the Bronze Birch Borer, \u3ci\u3eAgrilus Anxius\u3c/i\u3e (Coleoptera: Buprestidae)
The bronze birch borer is a contributing factor in birch dieback. It is believed that host condition has a major influence on the development of the borer. We found that the host tree\u27s apparent condition does not appear to influence post first instar development
Detection of Bronze Birch Borer Larvae and Pupae by Radiographs (Coleoptera: Buprestidae)
Bronze birch borer larvae and pupae were detected in small branches through the use of a portable X-ray unit. The optimum exposure time was 40 sec at 55 kV
Reforming Immigration Law to Allow More Foreign Student Entrepreneurs to Launch Job-Creating Ventures in the United States
As universities move toward a more experiential approach to entrepreneurship education, many academic units and cross-campus entrepreneurship programs are encouraging their students to actively engage with the curriculum and apply the skills they learn. One such approach is to have students start their own businesses before they graduate. In addition to enhancing their education, participation in the planning, launch and operation of a start-up venture can lead directly to the creation of new jobs for many other individuals. Unfortunately, being the founder of a start-up venture in the United States proves complicated for foreign students in our colleges and universities. Across the country, both undergraduate and graduate entrepreneurship students desiring to participate actively in a startup face vexing immigration law challenges. This paper outlines some of the barriers that foreign student entrepreneurs face, and describes how bipartisan legislation would help to address some of these roadblocks
The kinematic Sunyaev Zeldovich effect and transverse cluster velocities
The polarization of the CMBR scattered by galaxy clusters in the kinematic
Sunyaev Zeldovich effect depends on the transverse velocity of the cluster.
This polarizing effect is proportional to the transverse velocity squared, and
so weaker that the change in intensity due to the radial motion in the
kinematic effect. The value given by Sunyaev and Zeldovich, and which is
frequently cited, underestimates the polarizing effect by a factor of ten. We
show furthermore that the polarization has a strong frequency dependence. This
means that the polarization should be detectable with the new generation of
CMBR probes, at least for some clusters. Thus this effect offers, almost
uniquely, a method of obtaining the vectorial velocity of clusters.Comment: Submitted to MNRAS letter. 5 pages using mnras file style. email:
[email protected]
The use of light polarization for weak-lensing inversions
The measurement of the integrated optical polarization of weakly
gravitationally lensed galaxies can provide considerable constraints on lens
models. The method outlined depends on fact that the orientation of the
direction of optical polarization is not affected by weak gravitational
lensing. The angle between the semi-major axis of the imaged galaxy and the
direction of integrated optical polarization thus informs one of the distortion
produced by the gravitational lensing. Although the method depends on the
polarimetric measurement of faint galaxies, large telescopes and improved
techniques should make such measurements possible in the near future.Comment: 13 pages, 11 figures, uses mnras style file. Accepted for publication
in MNRA
Optimal Galaxy Distance Estimators
The statistical properties of galaxy distance estimators are studied and a
rigorous framework is developed for identifying and removing the effects of
Malmquist bias due to obsevational selection. The prescription of Schechter
(1980) for defining unbiased distance estimators is extended to more general --
and more realistic -- cases. The derivation of `optimal' unbiased distance
estimators of minimum dispersion, by utilising information from additional --
suitably correlated -- observables, is discussed and the results applied to a
calibrating sample from the Fornax cluster, as used in the Mathewson spiral
galaxy redshift survey. The optimal distance estimator derived from I-band
magnitude, diameter and 21cm line width has an intrinsic scatter which is 25 \%
smaller than that of the Tully-Fisher relation quoted for this calibrating
sample. (Figures are available on request).Comment: Plain Latex, 19 pages, Sussex-AST-93/9-
Geology of the Mohon Mountain volcanic field, Yavapai and Mohave Counties, Arizona: A preliminary report
Field mapping has produced a preliminary picture of Mohon Mountain as a composite volcano, in which pyroclastic ash and larger tephra erupted alternately with flows of rhyodacite and dacite. An analog study which uses imagery of lunar and Martian features will compare the overall shape of the vent complex, including its breached southern flank and satellite vents, to similar landforms found on Mars and the Moon which are believed to have formed similar processes. Ash flow sheets were hypothesized to comprise the outer slopes of Olympus Mons suggesting that explosive eruptions which are more volatile-rich than those which produce basalt flows are not confined to terrestrial settings but may also be found on bodies such as Mars, which have a thicker crust and deeper magma source in the mantle. The analog study will explore further evidence for explosive eruptions on Mars and the Moon
Sonoluminescence in Neutron Stars
After a brief discussion of a possible relationship between the electroweak
phase transition in highly compressed matter and gravitational collapse, we
examine the speculative possibility that the electroweak phase transition might
be contemporarily occurring in processes in neutron stars. We conjecture that
adiabatic compression of neutron star matter due to focusing of the energy from
a supernova bounce into a very small volume could result in extreme densities,
and Fermi levels or temperature above (100 GeV). We propose a
qualitative scenario for sonoluminescence in neutron stars and discuss possible
observable consequences.Comment: 10 pages, LATEX format (requires worldsci.sty style file
STRONGLY COUPLED ELECTROWEAK SYMMETRY BREAKING: IMPLICATIONS OF MODELS
We discuss the phenomenology of models of dynamical electroweak symmetry
breaking which attempt to generate the observed fermion mass spectrum. After
briefly describing the variety of and constraints on proposed models, we
concentrate on the signatures of colored pseudo-Nambu-Goldstone bosons and
resonances at existing and proposed colliders. These particles provide a
possibly unique signature: strongly produced resonances associated with
electroweak symmetry breaking. (This is the subgroup report for the
``Electroweak Symmetry Breaking and Beyond the Standard Model" working group of
the DPF Long Range Planning Study. This report will appear as a chapter in
``Electroweak Symmetry Breaking and Beyond the Standard Model", edited by T.
Barklow, S. Dawson, H.E. Haber, and J. Siegrist, to be published by World
Scientific.
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