4,514 research outputs found
A study of course deviations during cross-country soaring
Several models are developed for studying the impact of deviations from course during cross country soaring flights. Analyses are performed at the microstrategy and macrostrategy levels. Two types of lift sources are considered: concentrated thermals and thermal streets. The sensitivity of the optimum speed solutions to various model, piloting and performance parameters is evaluated. Guides are presented to provide the pilot with criterions for making in-flight decisions. In general, course deviations are warranted during weak lift conditions, but are less justifiable with moderate to strong lift conditions
CHARACTERISTIC OF BODY POSTURE OF THE PARTICIPANTS OF THE EUROPEAN JUNIOR VOLLEYBALL CHAMPIONSHIPS.
The lecture presents methods and results of study of volleyball players posture, age17-18 of different nationalities. The results show change curves in spine and biomechanical parameters under loading influence
Photon number resolving detection using time-multiplexing
Detectors that can resolve photon number are needed in many quantum
information technologies. In order to be useful in quantum information
processing, such detectors should be simple, easy to use, and be scalable to
resolve any number of photons, as the application may require great portability
such as in quantum cryptography. Here we describe the construction of a
time-multiplexed detector, which uses a pair of standard avalanche photodiodes
operated in Geiger mode. The detection technique is analysed theoretically and
tested experimentally using a pulsed source of weak coherent light.Comment: 20 pages, 14 figures, accepted to Journal of Modern Optic
Full-disc CO(1-0) mapping across nearby galaxies of the EMPIRE survey and the CO-to-H conversion factor
Carbon monoxide (CO) provides crucial information about the molecular gas
properties of galaxies. While CO has been targeted extensively,
isotopologues such as CO have the advantage of being less optically
thick and observations have recently become accessible across full galaxy
discs. We present a comprehensive new dataset of CO(1-0) observations
with the IRAM 30-m telescope of the full discs of 9 nearby spiral galaxies from
the EMPIRE survey at a spatial resolution of 1.5kpc. CO(1-0) is
mapped out to and detected at high signal-to-noise throughout our
maps. We analyse the CO(1-0)-to-CO(1-0) ratio () as a
function of galactocentric radius and other parameters such as the
CO(2-1)-to-CO(1-0) intensity ratio, the 70-to-160m flux
density ratio, the star-formation rate surface density, the star-formation
efficiency, and the CO-to-H conversion factor. We find that varies by
a factor of 2 at most within and amongst galaxies, with a median value of 11
and larger variations in the galaxy centres than in the discs. We argue that
optical depth effects, most likely due to changes in the mixture of
diffuse/dense gas, are favored explanations for the observed variations,
while abundance changes may also be at play. We calculate a spatially-resolved
CO(1-0)-to-H conversion factor and find an average value of
cm (K.km/s) over our sample with a standard
deviation of a factor of 2. We find that CO(1-0) does not appear to be a
good predictor of the bulk molecular gas mass in normal galaxy discs due to the
presence of a large diffuse phase, but it may be a better tracer of the mass
than CO(1-0) in the galaxy centres where the fraction of dense gas is
larger.Comment: accepted for publication in MNRA
A Portrait of Cold Gas in Galaxies at 60pc Resolution and a Simple Method to Test Hypotheses That Link Small-Scale ISM Structure to Galaxy-Scale Processes
The cloud-scale density, velocity dispersion, and gravitational boundedness
of the interstellar medium (ISM) vary within and among galaxies. In turbulent
models, these properties play key roles in the ability of gas to form stars.
New high fidelity, high resolution surveys offer the prospect to measure these
quantities across galaxies. We present a simple approach to make such
measurements and to test hypotheses that link small-scale gas structure to star
formation and galactic environment. Our calculations capture the key physics of
the Larson scaling relations, and we show good correspondence between our
approach and a traditional "cloud properties" treatment. However, we argue that
our method is preferable in many cases because of its simple, reproducible
characterization of all emission. Using, low-J 12CO data from recent surveys,
we characterize the molecular ISM at 60pc resolution in the Antennae, the Large
Magellanic Cloud, M31, M33, M51, and M74. We report the distributions of
surface density, velocity dispersion, and gravitational boundedness at 60pc
scales and show galaxy-to-galaxy and intra-galaxy variations in each. The
distribution of flux as a function of surface density appears roughly lognormal
with a 1sigma width of ~0.3 dex, though the center of this distribution varies
from galaxy to galaxy. The 60pc resolution line width and molecular gas surface
density correlate well, which is a fundamental behavior expected for virialized
or free-falling gas. Varying the measurement scale for the LMC and M31, we show
that the molecular ISM has higher surface densities, lower line widths, and
more self-gravity at smaller scales.Comment: Accepted for publication in the Astrophysical Journal, 36 pages
(24+appendix), 21 figures (12+appendix), until publication high resolution
version at http://www.astronomy.ohio-state.edu/~leroy.42/cloudscale.pd
Structure-function-dynamics relationships in the peculiar Planktothrix PCC7805 OCP1: impact of his-tagging and carotenoid type
The orange carotenoid protein (OCP) is a photoactive protein involved in cyanobacterial photoprotection. Here, we report on the functional, spectral and structural characteristics of the peculiar Planktothrix PCC7805 OCP (Plankto-OCP). We show that this OCP variant is characterized by higher photoactivation and recovery rates, and a stronger energy-quenching activity, compared to other OCPs studied thus far. We characterize the effect of the functionalizing carotenoid and of his-tagging on these reactions, and the time scales on which these modifications affect photoactivation. The presence of a His-tag at the C-terminus has a large influence on photoactivation, thermal recovery and PBS-fluorescence quenching, and likewise for the nature of the carotenoid that additionally affects the yield and characteristics of excited states and the ns-s dynamics of photoactivated OCP. By solving the structures of Plankto-OCP in the ECN- and CAN-functionalized states, each in two closely-related crystal forms, we further unveil the molecular breathing motions that animate Plankto-OCP at the monomer and dimer levels. We finally discuss the structural changes that could explain the peculiar properties of Plankto-OCP. - Complete functional characterization of Synechocystis and Planktothrix OCPs - Hitherto unknown structures of ECN- and CAN-functionalized Planktothrix OC
Conditional generation of arbitrary multimode entangled states of light with linear optics
We propose a universal scheme for the probabilistic generation of an
arbitrary multimode entangled state of light with finite expansion in Fock
basis. The suggested setup involves passive linear optics, single photon
sources, strong coherent laser beams, and photodetectors with single-photon
resolution. The efficiency of this setup may be greatly enhanced if, in
addition, a quantum memory is available.Comment: 7 pages, 5 figure
A far-infrared spectroscopic survey of intermediate redshift (ultra) luminous infrared galaxies
We present Herschel far-IR photometry and spectroscopy as well as ground-based CO observations of an intermediate redshift (0.21 _ z _ 0.88) sample of Herschel-selected (ultra)-luminous infrared galaxies (LIR >1011.5 L_). With these measurements, we trace the dust continuum, far-IR atomic line emission, in particular [C ii] 157.7μm, as well as the molecular gas of z ∼ 0.3 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and perform a detailed investigation of the interstellar medium of the population. We find that the majority of Herschel-selected intermediate redshift (U)LIRGs have LCii/LFIR ratios that are a factor of about 10 higher than that of local ULIRGs and comparable to that of local normal and high-z star-forming galaxies. Using our sample to bridge local and high-z [C ii] observations, we find that the majority of galaxies at all redshifts and all luminosities follow an LCii−LFIR relation with a slope of unity, from which local ULIRGs and high-z active-galactic-nucleus-dominated sources are clear outliers.We also confirm that the strong anti-correlation between the LCii/LFIR ratio and the far-IR color L60/L100 observed in the local universe holds over a broad range of redshifts and luminosities, in the sense that warmer sources exhibit lower LC ii/LFIR at any epoch. Intermediate redshift ULIRGs are also characterized by large molecular gas reservoirs and by lower star formation efficiencies compared to that of local ULIRGs. The high LC ii/LFIR ratios, the moderate star formation efficiencies (LIR/L _COor LIR/MH2 ), and the relatively low dust temperatures of our sample (which are also common characteristics of high-z star-forming galaxies with ULIRG-like luminosities) indicate that the evolution of the physical properties of (U)LIRGs between the present day and z > 1 is already significant by z ∼ 0.3
Measurement of the p\bar{p}\sqrt{s}$ = 1.8 TeV
We update the measurement of the top production cross section using the CDF
detector at the Fermilab Tevatron. This measurement uses decays to
the final states +jets and +jets. We search for quarks from
decays via secondary-vertex identification or the identification of
semileptonic decays of the and cascade quarks. The background to the
production is determined primarily through a Monte Carlo simulation.
However, we calibrate the simulation and evaluate its uncertainty using several
independent data samples. For a top mass of 175 , we measure
pb and pb using
the secondary vertex and the lepton tagging algorithms, respectively. Finally,
we combine these results with those from other decay channels and
obtain pb.Comment: The manuscript consists of 130 pages, 35 figures and 42 tables in
RevTex. The manuscript is submitted to Physical Review D. Fixed typo in
author lis
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