484 research outputs found
EXPLORING THE ROLE OF OSPREYS IN EDUCATION
Recent research in childhood education has demonstrated that experiences in nature are important in shaping early environmental consciousness (Hinds and Sparks 2008, Hussar and Horvath 2011, Cheng and Monroe 2012) and ultimately the expression of pro-environmental attitudes and behaviors during adulthood (Wells and Lekies 2006, Chawla and Cushing 2007, Collado et al. 2013). Increasingly, those experiences happen via written and electronic media (e.g., textbooks, computer screens) or in very anthropogenic environments (e.g., in parks and zoos) and less through direct contact with nature, a concept Louv (2005) referred to as ‘‘nature deficit disorder.’’ Even in schools where environmental education is prioritized, the extent of access to outdoor classroom activities or experiential learning opportunities can limit the degree to which children can observe, explore, and directly experience the natural world (Hudson 2001, Louv 2005, Ernst 2009). Interestingly, the same information technologies that might serve to limit contact with nature also have the potential to enhance and encourage interest and concern for the natural world (Blewitt 2011, Pearson et al. 2011). We believe this is an important paradox that warrants much further exploration and evaluation within educational and scientific communities
Classical Logical versus Quantum Conceptual Thought: Examples in Economics, Decision theory and Concept Theory
Inspired by a quantum mechanical formalism to model concepts and their
disjunctions and conjunctions, we put forward in this paper a specific
hypothesis. Namely that within human thought two superposed layers can be
distinguished: (i) a layer given form by an underlying classical deterministic
process, incorporating essentially logical thought and its indeterministic
version modeled by classical probability theory; (ii) a layer given form under
influence of the totality of the surrounding conceptual landscape, where the
different concepts figure as individual entities rather than (logical)
combinations of others, with measurable quantities such as 'typicality',
'membership', 'representativeness', 'similarity', 'applicability', 'preference'
or 'utility' carrying the influences. We call the process in this second layer
'quantum conceptual thought', which is indeterministic in essence, and contains
holistic aspects, but is equally well, although very differently, organized
than logical thought. A substantial part of the 'quantum conceptual thought
process' can be modeled by quantum mechanical probabilistic and mathematical
structures. We consider examples of three specific domains of research where
the effects of the presence of quantum conceptual thought and its deviations
from classical logical thought have been noticed and studied, i.e. economics,
decision theory, and concept theories and which provide experimental evidence
for our hypothesis.Comment: 14 page
The high-pressure phase of boron, {\gamma}-B28: disputes and conclusions of 5 years after discovery
{\gamma}-B28 is a recently established high-pressure phase of boron. Its
structure consists of icosahedral B12 clusters and B2 dumbbells in a NaCl-type
arrangement (B2){\delta}+(B12){\delta}- and displays a significant charge
transfer {\delta}~0.5- 0.6. The discovery of this phase proved essential for
the understanding and construction of the phase diagram of boron. {\gamma}-B28
was first experimentally obtained as a pure boron allotrope in early 2004 and
its structure was discovered in 2006. This paper reviews recent results and in
particular deals with the contentious issues related to the equation of state,
hardness, putative isostructural phase transformation at ~40 GPa, and debates
on the nature of chemical bonding in this phase. Our analysis confirms that (a)
calculations based on density functional theory give an accurate description of
its equation of state, (b) the reported isostructural phase transformation in
{\gamma}-B28 is an artifact rather than a fact, (c) the best estimate of
hardness of this phase is 50 GPa, (d) chemical bonding in this phase has a
significant degree of ionicity. Apart from presenting an overview of previous
results within a consistent view grounded in experiment, thermodynamics and
quantum mechanics, we present new results on Bader charges in {\gamma}-B28
using different levels of quantum-mechanical theory (GGA, exact exchange, and
HSE06 hybrid functional), and show that the earlier conclusion about
significant degree of partial ionicity in this phase is very robust
Demonstration of the temporal matter-wave Talbot effect for trapped matter waves
We demonstrate the temporal Talbot effect for trapped matter waves using
ultracold atoms in an optical lattice. We investigate the phase evolution of an
array of essentially non-interacting matter waves and observe matter-wave
collapse and revival in the form of a Talbot interference pattern. By using
long expansion times, we image momentum space with sub-recoil resolution,
allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure
Azimuthal anisotropy at RHIC: the first and fourth harmonics
We report the first observations of the first harmonic (directed flow, v_1),
and the fourth harmonic (v_4), in the azimuthal distribution of particles with
respect to the reaction plane in Au+Au collisions at the Relativistic Heavy Ion
Collider (RHIC). Both measurements were done taking advantage of the large
elliptic flow (v_2) generated at RHIC. From the correlation of v_2 with v_1 it
is determined that v_2 is positive, or {\it in-plane}. The integrated v_4 is
about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)
harmonics upper limits on the magnitudes are reported.Comment: 6 pages with 3 figures, as accepted for Phys. Rev. Letters The data
tables are at
http://www.star.bnl.gov/central/publications/pubDetail.php?id=3
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at GeV
Identified mid-rapidity particle spectra of , , and
from 200 GeV p+p and d+Au collisions are reported. A
time-of-flight detector based on multi-gap resistive plate chamber technology
is used for particle identification. The particle-species dependence of the
Cronin effect is observed to be significantly smaller than that at lower
energies. The ratio of the nuclear modification factor () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of in minimum-bias d+Au
collisions is found to be a factor of 2 lower than that in Au+Au collisions,
indicating that the Cronin effect alone is not enough to account for the
relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from
transverse momentum 1.8 GeV/c to 3. GeV/
Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV
We present the first measurement of directed flow () at RHIC. is
found to be consistent with zero at pseudorapidities from -1.2 to 1.2,
then rises to the level of a couple of percent over the range . The latter observation is similar to data from NA49 if the SPS rapidities
are shifted by the difference in beam rapidity between RHIC and SPS.
Back-to-back jets emitted out-of-plane are found to be suppressed more if
compared to those emitted in-plane, which is consistent with {\it jet
quenching}. Using the scalar product method, we systematically compared
azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow
from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure
Azimuthal anisotropy: the higher harmonics
We report the first observations of the fourth harmonic (v_4) in the
azimuthal distribution of particles at RHIC. The measurement was done taking
advantage of the large elliptic flow generated at RHIC. The integrated v_4 is
about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)
harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding
Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at \snn=130 GeV
Mid-rapidity transverse mass spectra and multiplicity densities of charged
and neutral kaons are reported for Au+Au collisions at \snn=130 GeV at RHIC.
The spectra are exponential in transverse mass, with an inverse slope of about
280 MeV in central collisions. The multiplicity densities for these particles
scale with the negative hadron pseudo-rapidity density. The charged kaon to
pion ratios are and
for the most central collisions. The ratio is lower than the same
ratio observed at the SPS while the is higher than the SPS result.
Both ratios are enhanced by about 50% relative to p+p and +p
collision data at similar energies.Comment: 6 pages, 3 figures, 1 tabl
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