2,715 research outputs found
Development of space stable thermal control coatings for use on large space vehicles
The evaluation and environmental testing of zinc orthotitanate pigments for use as space stable thermal control coatings on large space vehicles are discussed. Electron paramagnetic resonance spectra of the pigments and their precursor compounds are examined. A continuing study of the spectral intensity of mercury-argon and mercury-xenon sources in reported. Results of long term environmental testing of commercially available, strippable, protective coatings are discussed
Wolf, Canis lupus, Pup Mortality: Interspecific Predation or Non-Parental Infanticide?
A breeding male Gray Wolf, Canis lupus, equipped with a GPS collar was documented going to the den site of another Gray Wolf pack. This trip was coincident with an attack on the den of the other pack and the occurrence of a dead and partially consumed Gray Wolf pup at the same location. We present two possible explanations - interspecific predation and non-parental infanticide - to account for this observation. Because the Gray Wolf with the GPS collar and his mate were first-time breeders and were attempting to establish a territory space of their own, we speculate that, based on the available evidence, this observation most likely represents a case of non-parental infanticide that fits the predictions of the resource competition hypothesis
Evidence of Arboreal Lichen Use in Peatlands by White-tailed Deer, Odocoileus virginianus, in Northeastern Alberta
Within the past 10 to 15 years, White-tailed Deer (Odocoileus virginianus) have extended their geographical range to include most of northern Alberta. In the boreal forest they are most abundant in well-drained upland habitat. We report the occurrence of unusually large numbers of deer seen in a large fen complex in the west side of the Athabasca River Caribou range in northeastern Alberta. Further, we report an observation that suggests that deer may be using arboreal lichen (old man’s beard; Bryoria spp. and Usnea spp.) as a winter food in this region. We discuss the potential ecological ramifications of this observation for Woodland Caribou (Rangifer tarandus caribou) in northeastern Alberta
1H high resolution magic-angle coil spinning (HR-MACS) μNMR metabolic profiling of whole Saccharomyces cervisiae cells: a demonstrative study
International audienceThe low sensitivity and thus need for large sample volume is one of the major drawbacks of Nuclear Magnetic Resonance (NMR) spectroscopy. This is especially problematic for performing rich metabolic profiling of scarce samples such as whole cells or living organisms. This study evaluates a 1H HR-MAS approach for metabolic profiling of small volumes (250 nl) of whole cells. We have applied an emerging micro-NMR technology, high-resolution magic-angle coil spinning (HR-MACS), to study whole Saccharomyces cervisiae cells. We find that high-resolution high-sensitivity spectra can be obtained with only 19 million cells and, as a demonstration of the metabolic profiling potential, we perform two independent metabolomics studies identifying the significant metabolites associated with osmotic stress and agin
Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise
We observe measurement-induced qubit state mixing in a transmon qubit
dispersively coupled to a planar readout cavity. Our results indicate that
dephasing noise at the qubit-readout detuning frequency is up-converted by
readout photons to cause spurious qubit state transitions, thus limiting the
nondemolition character of the readout. Furthermore, we use the qubit
transition rate as a tool to extract an equivalent flux noise spectral density
at f ~ 1 GHz and find agreement with values extrapolated from a
fit to the measured flux noise spectral density below 1 Hz.Comment: 5 pages, 4 figures. Final journal versio
Tactics for Reasoning modulo AC in Coq
We present a set of tools for rewriting modulo associativity and
commutativity (AC) in Coq, solving a long-standing practical problem. We use
two building blocks: first, an extensible reflexive decision procedure for
equality modulo AC; second, an OCaml plug-in for pattern matching modulo AC. We
handle associative only operations, neutral elements, uninterpreted function
symbols, and user-defined equivalence relations. By relying on type-classes for
the reification phase, we can infer these properties automatically, so that
end-users do not need to specify which operation is A or AC, or which constant
is a neutral element.Comment: 16
Resonance fluorescence from an artificial atom in squeezed vacuum
We present an experimental realization of resonance fluorescence in squeezed
vacuum. We strongly couple microwave-frequency squeezed light to a
superconducting artificial atom and detect the resulting fluorescence with high
resolution enabled by a broadband traveling-wave parametric amplifier. We
investigate the fluorescence spectra in the weak and strong driving regimes,
observing up to 3.1 dB of reduction of the fluorescence linewidth below the
ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum
on the relative phase of the driving and squeezed vacuum fields. Our results
are in excellent agreement with predictions for spectra produced by a two-level
atom in squeezed vacuum [Phys. Rev. Lett. \textbf{58}, 2539-2542 (1987)],
demonstrating that resonance fluorescence offers a resource-efficient means to
characterize squeezing in cryogenic environments
Annual and monthly range fidelity of female boreal woodland caribou in respons to petroleum development
Petroleum-sector development in northern Alberta, Canada has been implicated as one factor influencing the decline of boreal woodland caribou (Rangifer tarandus caribou). Previous research showed that caribou are farther from petroleum-sector disturbances within their home range than expected. As petroleum development increases, the distance caribou can selectively place themselves relative to industrial disturbance must decrease, because distances between disturbances decrease. Conceptually, the number of local disturbances becomes so large that caribou either abandon their local avoidance behaviour or leave their traditional home range. We evaluated whether an intense petroleum- development event in northern Alberta was sufficient to result in home range abandonment by female woodland caribou. Using well locations as an index of petroleum development, we found that caribou studied from 1992 to 2000 did not change their annual or monthly range fidelity as a function of development intensity. Caribou remained in peatland complexes containing a large number of petroleum-sector disturbances rather than move to new areas, presumably because the risks of dispersing across upland habitat to reach other suitable habitat are high. Such range fidelity may have fitness consequences for woodland caribou if they suffer greater predation in areas where petroleum development is occurring
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