16,229 research outputs found
Analytical development of the planetary disturbing function on a digital computer
Fortran II IBM 7094 computer program for analytical development of planetary disturbing functio
The impact of college student immersion service learning trips on coping with stress and vocational identity
This study examined the impact of service learning immersion trips on vocational identity and coping with stress among college students. Fifty-one students (15 males, 36 females) who participated in immersion trips and 76 students (25 males, 51 females) in a non-immersion control group completed a series of questionnaires directly before and immediately after both fall and spring break immersion trips, and during a four-month follow up. Results suggest that, after returning from an immersion trip, students report a greater ability to cope with stress and a somewhat stronger sense of vocational identity relative to students who do not participate in immersion trips
Desequilibrio del ciclo del azufre y cambio ambiental durante el Período Ediacárico
A different approach is proposed here to solve the problem of negative δ13C excursions during the Ediacaran, by viewing them in terms of a linked carbon-sulfur-oxygen system, whereby changes in oxidant dynamics caused an excess of organic carbon oxidation over burial, resulting in a smaller DOM reservoir. The amount of oxidant required to achieve a deep negative carbon isotope excursion through net organic carbon oxidation may reasonably result from basin-scale evaporite dissolution.Se propone aquí un enfoque diferente para resolver el problema de las excursiones quimioestratigráficas negativas durante el Ediacárico, considerándolas en términos de un sistema vinculado de carbono-sulfuro-oxígeno, en el que los cambios en la dinámica de los oxidantes causarían un exceso de oxidación de carbono orgánico sobre el enterramiento, lo que resultaría en un depósito menor de DOM. La cantidad de oxidante requerida para lograr una excursión isotópica de carbono negativa a través de la oxidación de carbono orgánico neto puede resultar razonablemente de la disolución de evaporitaa a escala de cuenca
Nonlocal feedback in ferromagnetic resonance
Ferromagnetic resonance in thin films is analyzed under the influence of
spatiotemporal feedback effects. The equation of motion for the magnetization
dynamics is nonlocal in both space and time and includes isotropic, anisotropic
and dipolar energy contributions as well as the conserved Gilbert- and the
non-conserved Bloch-damping. We derive an analytical expression for the
peak-to-peak linewidth. It consists of four separate parts originated by
Gilbert damping, Bloch-damping, a mixed Gilbert-Bloch component and a
contribution arising from retardation. In an intermediate frequency regime the
results are comparable with the commonly used Landau-Lifshitz-Gilbert theory
combined with two-magnon processes. Retardation effects together with Gilbert
damping lead to a linewidth the frequency dependence of which becomes strongly
nonlinear. The relevance and the applicability of our approach to ferromagnetic
resonance experiments is discussed.Comment: 22 pages, 9 figure
Radio Observations of the Supernova Remnant Candidate G312.5-3.0
The radio images from the Parkes-MIT-NRAO (PMN) Southern Sky Survey at 4850
MHz have revealed a number of previously unknown radio sources. One such
source, G312.5-3.0 (PMN J1421-6415), has been observed using the
multi-frequency capabilities of the Australia Telescope Compact Array (ATCA) at
frequencies of 1380 MHz and 2378 MHz. Further observations of the source were
made using the Molonglo Observatory Synthesis Telescope (MOST) at a frequency
of 843 MHz. The source has an angular size of 18 arcmin and has a distinct
shell structure. We present the reduced multi-frequency observations of this
source and provide a brief argument for its possible identification as a
supernova remnant.Comment: 5 pages, 5 figures, Accepted for publication in MNRA
Measuring Active-Sterile Neutrino Oscillations with a Stopped Pion Neutrino Source
The question of the existence of light sterile neutrinos is of great interest
in many areas of particle physics, astrophysics, and cosmology. Furthermore,
should the MiniBooNE experiment at Fermilab confirm the LSND oscillation
signal, then new measurements are required to identify the mechanism
responsible for these oscillations. Possibilities include sterile neutrinos, CP
or CPT violation, variable mass neutrinos, Lorentz violation, and extra
dimensions. In this paper, we consider an experiment at a stopped pion neutrino
source to determine if active-sterile neutrino oscillations with delta-m
greater than 0.1 eV2 can account for the signal. By exploiting stopped pi+
decay to produce a monoenergetic nu_mu source, and measuring the rate of the
neutral current reaction nu_x + 12C -> nu_x +12C* as a function of distance
from the source, we show that a convincing test for active-sterile neutrino
oscillations can be performed.Comment: 10 pages, 9 figure
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Notations and conventions in molecular spectroscopy: part 1. General spectroscopic notation
The field of Molecular Spectroscopy was surveyed in order to determine a set of
conventions and symbols which are in common use in the spectroscopic literature. This
document, which is Part I in a series, establishes the notations and conventions used for
general spectroscopic notations and deals with quantum mechanics, quantum numbers
(vibrational states, angular momentum and energy levels), spectroscopic transitions, and
miscellaneous notations (e.g. spectroscopic terms). Further parts will follow, dealing inter
alia with symmetry notation, permutation and permutation-inversion symmetry notation,
vibration-rotation spectroscopy and electronic spectroscopy
The solution structure of sarafotoxin-c: implications for ligand recognition by endothelin
The solution structure of sarafotoxin-c has been determined using NMR spectroscopy. A total of 112 interproton distance constraints derived from two-dimensional MMR spectra were used to calculate a family of structures using a combination of distance geometry and dynamical simulated annealing calculations. The structures reveal a well defined cu helix extending from Glu(9) to Cys(15) and an N-terminal region (Cys(1)-Asp(8)) that is tightly constrained by disulfide bands to Cys residues in the central helix. In contrast, the C-terminal region (His(16)-Trp(21)) does not adopt a defined conformation in the final family of structures. This is consistent with the paucity of NMR-derived structural constraints obtained for this region and leads to the suggestion that the C-terminal region oscillates rapidly between a number of substantially different conformers. It is proposed that differences between the central helix of the endothelin and sarafotoxin isopeptides might be important in binding of these ligands by the G protein-coupled endothelin receptors
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