60,623 research outputs found
Is 4U 0114+65 an eclipsing HMXB?
We present the pulsation and spectral characteristics of the HMXB 4U 0114+65
during a \emph{Suzaku} observation covering the part of the orbit that included
the previously known low intensity emission of the source (dip) and the egress
from this state. This dip has been interpreted in previous works as an X-ray
eclipse. Notably, in this Suzaku observation, the count rate during and outside
the dip vary by a factor of only 2-4 at odds with the eclipses of other HMXBs,
where the intensity drops upto two orders of magnitude. The orbital intensity
profile of 4U 0114+65 is characterized by a narrow dip in the RXTE-ASM (2-12
\rm{keV}) light curve and a shallower one in the Swift-BAT (15-50 \rm{keV}),
which is different from eclipse ingress/egress behaviour of other HMXBs. The
time-resolved spectral analysis reveal moderate absorption column density
(N - 2-20 atoms ) and a relatively low
equivalent width ( 30 \rm{eV} \& 12 \rm{eV} of the iron K and
K lines respectively) as opposed to the typical X-ray spectra of HMXBs
during eclipse where the equivalent width is 1 \rm{keV}. Both XIS and
PIN data show clear pulsations during the dip, which we have further confirmed
using the entire archival data of the IBIS/ISGRI and JEM-X instruments onboard
\emph{INTEGRAL}. The results we presented question the previous interpretation
of the dip in the light curve of 4U 0114+65 as an X-ray eclipse. We thus
discuss alternative interpretations of the periodic dip in the light curve of
4U 0114+65.Comment: 16 pages, 7 figures, 1 table, Accepted in MNRA
Small carrion beetles (Coleoptera: Leiodidae: Cholevinae) from burrows of Geomys and Thomomys pocket gophers (Rodentia: Geomyidae) in the United States
The cholevine beetles inhabiting burrows of Geomys and Thomomys pocket gophers (Rodentia: Geomyidae) are reviewed. Catops geomysi n. sp. and Ptomaphagus geomysi n. sp. are described. Both of these species and Ptomaphagus schwarzi Hatch appear to be regular and obligate inhabitants of Geomys burrows b~t are not host specific. Nemadus hornii Hatch, Sciodrepoides watsoni horn ian us (Blanchard), Catops s~mplex Say, Ptomaphagus cavernicola Schwarz, Ptomaphagus consobrinus (LeConte), Ptomaphagus fisus Horn, and Ptomaphagus texanus Horn were less frequently collected and are probably facultative inhabitants of Geomys burrows, as well as nests or dens of other small mammals. Ptomaphagus nevadicus Horn is an inhabitant of ~)Urrows of Thomomys pocket gophers in western North America. A key to the species of Ptomaphagus III the southeastern Gulf Coastal Plain, from non-cave habitats, is provided to aid in their identification
Four new Aphodius Illiger from pocket gopher burrows in Arizona, Utah, Kansas and Nebraska (Coleoptera: Scarabaeidae: Aphodiinae)
We describe four new species of winter-active Aphodius (sensu lato) from pocket gopher burrows in Arizona, Utah, Kansas, and Nebraska: A. cacabatus, A. paulseni, A. skillmani, and A. utopensis. Diagnostic characters of all four species are illustrated
Petrochemical and petrophysical characterization of the lower crust and the Moho beneath the West African Craton, based on Xenoliths from Kimberlites
Additional evidence to the composition of the lower crust and uppermost mantle was presented in the form of xenolith data. Xenoliths from the 2.7-Ga West African Craton indicate that the Moho beneath this shield is a chemically and physically gradational boundary, with intercalations of garnet granulite and garnet eclogite. Inclusions in diamonds indicate a depleted upper mantle source, and zenolith barometry and thermometry data suggest a high mantle geotherm with a kink near the Moho. Metallic iron in the xenoliths indicates that the uppermost mantle has a significant magnetization, and that the depth to the Curie isotherm, which is usually considered to be at or above the Moho, may be deeper than the Moho
Thermal stress analysis of ceramic structures with NASTRAN isoparametric solid elements
The performance of the NASTRAN level 16.0, twenty node, isoparametric bricks (CIHEX2) at thermal loading was studied. A free ceramic plate was modelled using twenty node bricks of varying thicknesses. The thermal loading for this problem was uniform over the surface with an extremely large gradient through the thickness. No mechanical loading was considered. Temperature-dependent mechanical properties were considered in this analysis. The NASTRAN results were compared to one dimensional stress distributions calculated by direct numerical integration
Variable features in the Valles Marineris region of Mars
Transient phenomena on Mars have long been recognized in Mariner and Viking images as well as in decades of Earth based telescopic observations. These events are of interest because of the information they present on currently active meteorological and geological processes. Changes in surface albedo patterns and atmospheric conditions can also affect the analysis and interpretation of data based on spectral or morphological properties of geologic units on the surface. The mechanism responsible for albedo pattern change is currently under investigation. Generation and subsequent transportation and deposition of dark sands has been interpreted in the Valles. However, the removal of a bright dust layer is more consistent with the rapid time period of the change (about two months) and with preliminary multispectral mapping results which suggest that the dark streak south of Eos and Coprates Chasmata is spectrally distinguishable from the dark saltating materials found elsewhere in the canyon system. If a layer of bright dust was removed to affect the albedo change, questions concerning how such micron-sized particles are mobilized by the winds during a normally quiescent season (Southern Hemisphere Autumn) should be addressed
Expected Precision of Higgs Boson Partial Widths within the Standard Model
We discuss the sources of uncertainty in calculations of the partial widths
of the Higgs boson within the Standard Model. The uncertainties come from two
sources: the truncation of perturbation theory and the uncertainties in input
parameters. We review the current status of perturbative calculations and note
that these are already reaching the parts-per-mil level of accuracy for the
major decay modes. The main sources of uncertainty will then come from the
parametric dependences on alpha_s, m_b, and m_c. Knowledge of these parameters
is systematically improvable through lattice gauge theory calculations. We
estimate the precision that lattice QCD will achieve in the next decade and the
corresponding precision of the Standard Model predictions for Higgs boson
partial widths.Comment: 20 pages, 1 figure; v2: minor typo correction
Phase diagram of CeVSb3 under pressure and its dependence on pressure conditions
We present temperature dependent resistivity and ac-calorimetry measurements
of CeVSb3 under pressure up to 8 GPa in a Bridgman anvil cell modified to use a
liquid medium and in a diamond anvil cell using argon as a pressure medium,
respectively. We observe an initial increase of the ferromagnetic transition
temperature Tc with pressures up to 4.5 GPa, followed by decrease of Tc on
further increase of pressure and finally its disappearance, in agreement with
the Doniach model. We infer a ferromagnetic quantum critical point around 7 GPa
under hydrostatic pressure conditions from the extrapolation to 0 K of Tc and
the maximum of the A coefficient from low temperature fits of the resistivity
\rho (T)=\rho_{0}+AT^{n}. No superconductivity under pressure was observed down
to 0.35 K for this compound. In addition, differences in the Tc(P) behavior
when a slight uniaxial component is present are noticed and discussed and
correlated to choice of pressure medium
The Economics of Processing Ethanol at Sugarmills: A Simulation Approach
Resource /Energy Economics and Policy,
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