44,550 research outputs found
Development and Sex Ratio of \u3ci\u3eMelittobia Australica\u3c/i\u3e and \u3ci\u3eM. Digitata\u3c/i\u3e (Hymenoptera: Eulophidae) on \u3ci\u3eMegachile Rotundata\u3c/i\u3e (Hymenoptera: Megachilidae) and \u3ci\u3eTrypoxylon Politum\u3c/i\u3e (Hymenoptera: Sphecidae)
Life history, development time, and sex ratio of Melittobia australica Girault and M. digitata Dahms on Megachile rotundata (Fabricius) and Trypoxylon politum Say are presented and compared with previous reports. Total development time and sex ratio differs slightly among the different hosts but falls within the expected range reported for different hosts and Melittobia species. The slightly longer development times and higher proportion of males recorded for both species on M. rotundata hosts probably reflects poorer host nutritional quality, relative to T. politum. We confirm that the one unusually extended development time reported by Schmieder for Melittobia chalybii Ashmead collected in New Jersey, can be accounted for as likely having represented a previously unknown species since described as M. femorata Dahms
Radiatively Induced Lorentz and CPT Violation in Schwinger Constant Field Approximation
The Schwinger proper-time method is an effective calculation method,
explicitly gauge invariant and nonperturbative. We make use of this method to
investigate the radiatively induced Lorentz and CPT-violating effects in
quantum electrodynamics when an axial vector interaction term is introduced in
the fermionic sector. The induced Lorentz and CPT-violating Chern-Simons term
coincides with the one obtained using a covariant derivative expansion but
differs from the result usually obtained in other regularization schemes. A
possible ambiguity in the approach is also discussed.Comment: 11 pages, REVTeX, typos and a few equations corrected, a comment
added to the conclusions, acknowledgments adde
The role of slip transfer at grain boundaries in the propagation of microstructurally short fatigue cracks in Ni-based superalloys
Crack initiation and propagation under high-cycle fatigue conditions have
been investigated for a polycrystalline Ni-based superalloy by in-situ
synchrotron assisted diffraction and phase contrast tomography. The cracks
nucleated along the longest coherent twin boundaries pre-existing on the
specimen surface, that were well oriented for slip and that presented a large
elastic incompatibility across them. Moreover, the propagation of
microstructurally short cracks was found to be determined by the easy slip
transfer paths across the pre-existing grain boundaries. This information can
only be obtained by characterization techniques like the ones presented here
that provide the full set of 3D microstructural information
Parent Stars of Extrasolar Planets. XI. Trends with Condensation Temperature Revisited
We report the results of abundance analyses of new samples of stars with
planets and stars without detected planets. We employ these data to compare
abundance-condensation temperature trends in both samples. We find that stars
with planets have more negative trends. In addition, the more metal-rich stars
with planets display the most negative trends. These results confirm and extend
the findings of Ramirez et al. (2009) and Melendez et al. (2009), who
restricted their studies to solar analogs. We also show that the differences
between the solar photospheric and CI meteoritic abundances correlate with
condensation temperature.Comment: 7 pages, 11 figures; to be published in MNRA
On the Interpretation of the Atmospheric Neutrino Data in Terms of Flavor Changing Neutrino Interactions
Flavour changing (FC) neutrino-matter interactions have been proposed as a
solution to the atmospheric neutrino anomaly. Here we perform the analysis of
the full set of the recent 52 kTy Super-Kamiokande atmospheric neutrino data,
including the zenith angle distribution of the contained events as well as the
higher energy upward-going stopping and through-going muon events. Our results
show that the FC mechanism can describe the full data sample with a
chi^2_{min}=44/(33 d.o.f) which is acceptable at the 90% confidence level. The
combined analysis confines the amount of FC to be either close to maximal or to
the level of about (10-50)%.Comment: 15 pages, 4 Postscript figures, uses ReVTeX. Updated analysis to 52
kTy Super-Kamiokande data. A new figure for the up-down asymmetry is
included. Some comments and references are adde
Global three-neutrino oscillation analysis of neutrino data
A global analysis of the solar, atmospheric and reactor neutrino data is
presented in terms of three-neutrino oscillations. We include the most recent
solar neutrino rates of Homestake, SAGE, GALLEX and GNO, as well as the recent
1117 day Super-Kamiokande data sample, including the recoil electron energy
spectrum both for day and night periods and we treat in a unified way the full
parameter space for oscillations, correctly accounting for the transition from
the matter enhanced (MSW) to the vacuum oscillations regime. Likewise, we
include in our description conversions with . For the
atmospheric data we perform our analysis of the contained events and the
upward-going -induced muon fluxes, including the previous data samples of
Frejus, IMB, Nusex, and Kamioka experiments as well as the full 71 kton-yr
(1144 days) Super-Kamiokande data set, the recent 5.1 kton-yr contained events
of Soudan2 and the results on upgoing muons from the MACRO detector. We first
present the allowed regions of solar and atmospheric oscillation parameters
, and , ,
respectively, as a function of and determine the constraints from
atmospheric and solar data on the mixing angle , common to solar
and atmospheric analyses. We also obtain the allowed ranges of parameters from
the full five-dimensional combined analysis of the solar, atmospheric and
reactor data.Comment: 56 pages, 21 postscript figures. Some misprints corrected and new
references added. Chooz limit included in Fig.21. Final version to appear in
Phys. Rev.
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