227 research outputs found
The origin of pointing: Evidence for the touch hypothesis
Pointing gestures play a foundational role in human language, but up to now, we have not known where these gestures come from. Here, we investigated the hypothesis that pointing originates in touch. We found, first, that when pointing at a target, children and adults oriented their fingers not as though trying to create an “}arrow{” that picks out the target but instead as though they were aiming to touch it; second, that when pointing at a target at an angle, participants rotated their wrists to match that angle as they would if they were trying to touch the target; and last, that young children interpret pointing gestures as if they were attempts to touch things, not as arrows. These results provide the first substantial evidence that pointing originates in touch
Laser pump X ray probe experiments with electrons ejected from a Cu 111 target space charge acceleration
A comprehensive investigation of the emission characteristics for electrons induced by X rays of a few hundred eV at grazing incidence angles on an atomically clean Cu 111 sample during laser excitation is presented. Electron energy spectra due to intense infrared laser irradiation are investigated at the BESSY II slicing facility. Furthermore, the influence of the corresponding high degree of target excitation high peak current of photoemission on the properties of Auger and photoelectrons liberated by a probe X ray beam is investigated in time resolved pump and probe measurements. Strong electron energy shifts have been found and assigned to space charge acceleration. The variation of the shift with laser power and electron energy is investigated and discussed on the basis of experimental as well as new theoretical result
Distribution Of Foraging Shearwaters Relative To Inner Front Of SE Bering Sea
We examined the hypothesis that short-tailed shearwaters Puffinus tenuirostris aggregate to forage at the inner front of the SE Bering Sea because of enhanced production there. We tested this hypothesis by comparing primary production, the distribution of euphausiids and the distribution of shearwaters relative to the front during late spring and late summer/early fall of 1997, 1998 and 1999. We found enhanced primary production at the front and offshore of the front during summer but not during spring. Primary production varied between seasons and years. Major differences were related to anomalous conditions in 1997 and 1998. The density of euphausiids was higher at the front and offshore of the front during summer, but there were no differences among regions during spring. Foraging shearwaters aggregated in high densities at the front during summer, but foraged close to shore during spring. At the front, shearwaters foraged on euphausiids Thysanoessa raschii and T. inermis as expected, and on copepods that accumulated in the area. The proportion of zooplankton consumed at the front decreased from summer 1997 to summer 1999, while consumption of sandlance Ammodytes hexapterus at this feature increased. Our results show that, during summer, the inner front supports aggregations of euphausiids and their seabird predators. The means by which the frontal system supports enhanced production and the subsequent trophic transfers is dependent on the availability of nutrients at depth in the frontal region and the aggregation of small zooplankton organisms in this feature
Configuration development study of the X-24C hypersonic research airplane
Bottom line results were made of a three-phase study to determine the feasibility of designing, building, and operating, and maintaining an air-launched high performance aircraft capable of cruising at speeds up to Mach 8 for short durations. The results show that Lockalloy heat-sink structure affords the capability for a 'work-horse' vehicle which can serve as an excellent platform for this research. It was further concluded that the performance of a blended wing body configuration surpassed that of a lifting body design for typical X-24C missions. The cost of a two vehicle program, less engines, B-52 modification and contractor support after delivery, can be kept within $70M (in Jan. 1976 dollars)
Nonlinear spin wave excitations at low magnetic bias fields
Nonlinear magnetization dynamics is essential for the operation of numerous spintronic devices ranging from magnetic memory to spin torque microwave generators. Examples are microwave assisted switching of magnetic structures and the generation of spin currents at low bias fields by high amplitude ferromagnetic resonance. Here we use X ray magnetic circular dichroism to determine the number density of excited magnons in magnetically soft Ni80Fe20 thin films. Our data show that the common model of nonlinear ferromagnetic resonance is not adequate for the description of the nonlinear behaviour in the low magnetic field limit. Here we derive a model of parametric spin wave excitation, which correctly predicts nonlinear threshold amplitudes and decay rates at high and at low magnetic bias fields. In fact, a series of critical spin wave modes with fast oscillations of the amplitude and phase is found, generalizing the theory of parametric spin wave excitation to large modulation amplitude
Dynamics of space charge acceleration of X ray generated electrons emitted from a metal surface
On-site correlation in valence and core states of ferromagnetic nickel
We present a method which allows to include narrow-band correlation effects
into the description of both valence and core states and we apply it to the
prototypical case of nickel. The results of an ab-initio band calculation are
used as input mean-field eigenstates for the calculation of self-energy
corrections and spectral functions according to a three-body scattering
solution of a multi-orbital Hubbard hamiltonian. The calculated quasi-particle
spectra show a remarkable agreement with photoemission data in terms of band
width, exchange splitting, satellite energy position of valence states, spin
polarization of both the main line and the satellite of the 3p core level.Comment: 14 pages, 10 PostScript figures, RevTeX, submitted to PR
Ex vivo drug response heterogeneity reveals personalized therapeutic strategies for patients with multiple myeloma
Multiple myeloma (MM) is a plasma cell malignancy defined by complex genetics and extensive patient heterogeneity. Despite a growing arsenal of approved therapies, MM remains incurable and in need of guidelines to identify effective personalized treatments. Here, we survey the ex vivo drug and immunotherapy sensitivities across 101 bone marrow samples from 70 patients with MM using multiplexed immunofluorescence, automated microscopy and deep-learning-based single-cell phenotyping. Combined with sample-matched genetics, proteotyping and cytokine profiling, we map the molecular regulatory network of drug sensitivity, implicating the DNA repair pathway and EYA3 expression in proteasome inhibitor sensitivity and major histocompatibility complex class II expression in the response to elotuzumab. Globally, ex vivo drug sensitivity associated with bone marrow microenvironmental signatures reflecting treatment stage, clonality and inflammation. Furthermore, ex vivo drug sensitivity significantly stratified clinical treatment responses, including to immunotherapy. Taken together, our study provides molecular and actionable insights into diverse treatment strategies for patients with MM
On the electronic structure of electron doped LaOFeAs as seen by X-ray absorption spectroscopy
We investigated the recently found superconductor LaO_{1-x}F_xFeAs by X-ray
absorption spectroscopy (XAS). From a comparison of the O K-edge with LDA
calculations we find good agreement and are able to explain the structure and
changes of the spectra with electron doping. An important result from this edge
is a limitation of the Hubbard U to values not significantly larger than 1 eV.
From experimental Fe L_2,3-edge spectra and charge transfer multiplet
calculations we gain further information on important physical values such as
hopping parameters, the charge transfer energy Delta, and the on-site Hubbard
U. Furthermore we find the system to be very covalent with a large amount of
ligand holes. A shift in the chemical potential is visible in the O K- and Fe
L_2,3-edge spectra which emphasizes the importance of band effects in these
compounds.Comment: 4 pages, 2 figure
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A springtime source of toxic Pseudo-nitzschia cells on razor clam beaches in the Pacific Northwest
Concentrations of domoic acid (DA) above the regulatory limit in Washington coast razor clams are usually higher on northern beaches from summer to fall. Recent field studies have confirmed that the primary source of toxic Pseudo-nitzschia (PN) cells in those seasons is a semi-retentive topographically trapped seasonal eddy located offshore and north of the clamming beaches. Another semi-retentive coastal feature, Heceta Bank, that has been shown to support toxic PN cells in summer, is located south of Washington's clamming beaches. In this paper we present evidence to demonstrate that Heceta Bank, although not a likely source of toxic cells to Washington in summer due to the prevailing southward seasonal currents, may be a source of cells in springtime before the southward currents develop. In contrast to summer and fall seasons, concentrations of DA in razor clams are typically higher at southern beaches in spring. The likelihood of a southern source is explored using biological and transport data surrounding a period of toxic razor clams in April 2005. In particular, satellite-derived chlorophyll data confirm that a bloom occurred over Heceta Bank in March of that year, just prior to a period of strong storm-driven northward transport. PN cells of the same species observed in the April bloom on Washington beaches and in offshore waters were documented in Oregon offshore waters on the northern edge of Heceta Bank. That species, P. australis, has been shown to be highly toxic in this region; shore-based data show that razor clams on Oregon beaches were also toxic at the time when P. australis was observed offshore. Both measured and modeled currents show that transport was more than sufficient to move cells from the vicinity of Heceta Bank, Oregon to southern Washington beaches by the time the toxic cells were observed on those beaches. The rapid transport was due in part to the presence of the buoyant plume from the Columbia River, a common feature in winter and spring in nearshore waters of the U.S. Pacific Northwest. (c) 2013 Elsevier B.V. All rights reserved.Keywords: Coastal currents, Heceta Bank, Domoic acid, HAB, Pseudo-nitzschia, Juan de Fuca edd
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