46 research outputs found
Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam
Neutral current single pi0 production induced by neutrinos with a mean energy
of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near
detector of the K2K long baseline neutrino experiment. The cross section for
this process relative to the total charged current cross section is measured to
be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of
produced pi0s is measured and is found to be in good agreement with an
expectation from the present knowledge of the neutrino cross sections.Comment: 6 pages, 4 figures, Submitted to Phys. Lett.
Light flavor asymmetry of nucleon sea
The light flavor antiquark distributions of the nucleon sea are calculated in
the effective chiral quark model and compared with experimental results. The
contributions of the flavor-symmetric sea-quark distributions and the nuclear
EMC effect are taken into account to obtain the ratio of Drell-Yan cross
sections , which can match well
with the results measured in the FermiLab E866/NuSea experiment. The calculated
results also match the measured from different
experiments, but unmatch the behavior of derived
indirectly from the measurable quantity
by the FermiLab E866/NuSea
Collaboration at large . We suggest to measure again
at large from precision experiments with careful experimental data
treatment. We also propose an alternative procedure for experimental data
treatment.Comment: 10 pages, 8 figures, final version to appear in EPJ
Diving into the vertical dimension of elasmobranch movement ecology
Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements
State of the worldâs plants and fungi 2020
Kewâs State of the Worldâs Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kewâs State of the Worldâs Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity
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The accuracy of the AATSR sea surface temperatures in the Caribbean
The Along-Track Scanning Radiometer (ATSR) series of instruments provides the means to obtain accurate measurements of sea surface temperature (SST), with a target total uncertainty of ±
0.3 K, 1
Ï. In this paper, we present validation results from 1 year of comparisons between 1 km resolution SSTs derived from the third instrument in the series, the Advanced ATSR (AATSR), and in situ measurements obtained during 2003 from the Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) over the Caribbean.
Our dataset consists of 99 cloud-free matchups, 25 of which are two-channel SST retrievals (daytime) and 74 three-channel SST retrievals (nighttime). Validation results for both dual- and nadir-view SSTs for these matchups are presented. We demonstrate that the dualânadir SST measurement difference (DâN) can be used to classify matchups and attribute the likely cause of a particularly high DâN to outbreaks of Saharan dust. Under conditions of ânormalâ DâN, the bias and standard deviation of the two- and three-channel dual-view retrievals is â
0.05 K and 0.26 K, and 0.02 K and 0.25 K, respectively. Dual-view SSTs obtained when the DâN is high over the Caribbean exhibit significant warm biases of 0.60 K and 0.32 K for two- and three-channel retrievals, respectively. Cool biases, with respect to the bias for ânormalâ DâN, are observed in the nadir three-channel (N3) SSTs; for matchups with high DâN, the bias and standard deviation are â
0.16 K and 0.31 K, compared with 0.14 K and 0.24 K for ânormalâ DâN. The distribution of the nadir two-channel retrievals is non-Gaussian and the apparent accuracy is comparatively poor, demonstrating clearly the advantages of using a sensor with dual-viewing capabilities to obtain a superior atmospheric correction, particularly when data from an additional short-wave infrared channel (e.g. at 3.7 ÎŒm) is not available
The OSIRIS Instrument on the Odin Spacecraft
The optical spectrograph and infrared imager system (OSIRIS) on board the Odin spacecraft is designed to retrieve altitude profiles of terrestrial atmospheric minor species by observing limb-radiance profiles. The grating optical spectrograph (OS) obtains spectra of scattered sunlight over the range 280-800 nm with a spectral resolution of approximately 1 nm. The Odin spacecraft performs a repetitive vertical limb scan to sweep the OS 1 km vertical field of view over selected altitude ranges from approximately 10 to 100 km. The terrestrial absorption features that are superimposed on the scattered solar spectrum are monitored to derive the minor species altitude profiles. The spectrograph also detects the airglow, which can be used to study the mesosphere and lower thermosphere. The other part of OSIRIS is a three-channel infrared imager (IRI) that uses linear array detectors to image the vertical limb radiance over an altitude range of approximately 100 km. The IRI observes both scattered sunlight and the airglow emissions from the oxygen infrared atmospheric band at 1.27 mum and the OH (3-1) Meinel band at 1.53 mum. A tomographic inversion technique is used with a series of these vertical images to derive the two-dimensional distribution of the emissions within the orbit plane
Future Development of the Operational AATSR LST Product
Future Development of the Operational AATSR LST Produc