26,650 research outputs found
GBCW Support for Shellfish Activities 2003
The Great Bay Coast Watch (GBCW) is a volunteer estuarine monitoring program established in 1989 that includes teachers, students, and local citizens with a diversity of backgrounds. Volunteers participate in a variety of training programs that enable them to monitor water quality parameters in Great Bay and coastal areas, sample for marine phytoplankton blooms and conduct shoreline surveys and habitat evaluations. Since 1997 the New Hampshire Estuaries Project (NHEP) has relied on the ability of GBCW to recruit and train volunteers to assist with the implementation of its plan to protect, restore and manage the states estuarine systems. This year GBCW again participated in plan implementation by assisting the NH Department of Environmental Services (NHDES) Shellfish Program. Volunteers completed a variety of work tasks, including mussel collection, sample collection and transport and general field assistance
2004 Support for Shellfish Program and Estuarine Education, Meeker, S & Reid, A
Working within the University of New Hampshire (UNH) Cooperative Extension/Sea Grant Program, the Great Bay Coast Watch (GBCW) is New Hampshire’s most wide ranging program for direct citizen involvement in monitoring estuarine and coastal systems. GBCW has a fifteen year history of educating citizens about the Great Bay Estuary, New Hampshire Seacoast, and Gulf of Maine watershed through active participation in monitoring and an accompanying education program. Based in Durham, NH, GBCW coordinates over 100 volunteers drawn from 19 New Hampshire and Southern Maine communities. In 1990, volunteers began monitoring eight sites on a monthly basis April through October. Today, this effort has grown to include 21 sites that are sampled monthly for water quality around the Great Bay estuary, and six coastal sites that are monitored weekly for harmful algae blooms. Volunteers include adults, students, and home schooled families
Viscous dark fluid universe
We investigate the cosmological perturbation dynamics for a universe
consisting of pressureless baryonic matter and a viscous fluid, the latter
representing a unified model of the dark sector. In the homogeneous and
isotropic background the \textit{total} energy density of this mixture behaves
as a generalized Chaplygin gas. The perturbations of this energy density are
intrinsically non-adiabatic and source relative entropy perturbations. The
resulting baryonic matter power spectrum is shown to be compatible with the
2dFGRS and SDSS (DR7) data. A joint statistical analysis, using also
Hubble-function and supernovae Ia data, shows that, different from other
studies, there exists a maximum in the probability distribution for a negative
present value of the deceleration parameter. Moreover,
while previous descriptions on the basis of generalized Chaplygin gas models
were incompatible with the matter power spectrum data since they required a
much too large amount of pressureless matter, the unified model presented here
favors a matter content that is of the order of the baryonic matter abundance
suggested by big-bang nucleosynthesis.Comment: 19 pages, 6 figure
Dynamical preparation of EPR entanglement in two-well Bose-Einstein condensates
We propose to generate Einstein-Podolsky-Rosen (EPR) entanglement between
groups of atoms in a two-well Bose-Einstein condensate using a dynamical
process similar to that employed in quantum optics. The local nonlinear S-wave
scattering interaction has the effect of creating a spin squeezing at each
well, while the tunneling, analogous to a beam splitter in optics, introduces
an interference between these fields that results in an inter-well
entanglement. We consider two internal modes at each well, so that the
entanglement can be detected by measuring a reduction in the variances of the
sums of local Schwinger spin observables. As is typical of continuous variable
(CV) entanglement, the entanglement is predicted to increase with atom number,
and becomes sufficiently strong at higher numbers of atoms that the EPR paradox
and steering non-locality can be realized. The entanglement is predicted using
an analytical approach and, for larger atom numbers, stochastic simulations
based on truncated Wigner function. We find generally that strong tunnelling is
favourable, and that entanglement persists and is even enhanced in the presence
of realistic nonlinear losses.Comment: 15 pages, 19 figure
Viscous dark fluid Universe: a unified model of the dark sector?
The Universe is modeled as consisting of pressureless baryonic matter and a
bulk viscous fluid which is supposed to represent a unified description of the
dark sector. In the homogeneous and isotropic background the \textit{total}
energy density of this mixture behaves as a generalized Chaplygin gas. The
perturbations of this energy density are intrinsically nonadiabatic and source
relative entropy perturbations. The resulting baryonic matter power spectrum is
shown to be compatible with the 2dFGRS and SDSS (DR7) data. A joint statistical
analysis, using also Hubble-function and supernovae Ia data, shows that,
different from other studies, there exists a maximum in the probability
distribution for a negative present value of the deceleration parameter.
Moreover, the unified model presented here favors a matter content that is of
the order of the baryonic matter abundance suggested by big-bang
nucleosynthesis. A problem of simple bulk viscous models, however, is the
behavior of the gravitational potential and the reproduction of the CMB power
spectrum.Comment: 12 pages, 3 figures, contributed paper to 8th Friedmann Seminar, 30
May to 3 June 2011, Rio de Janeiro, Brazi
Developing and Researching PhET simulations for Teaching Quantum Mechanics
Quantum mechanics is difficult to learn because it is counterintuitive, hard
to visualize, mathematically challenging, and abstract. The Physics Education
Technology (PhET) Project, known for its interactive computer simulations for
teaching and learning physics, now includes 18 simulations on quantum mechanics
designed to improve learning of this difficult subject. Our simulations include
several key features to help students build mental models and intuitions about
quantum mechanics: visual representations of abstract concepts and microscopic
processes that cannot be directly observed, interactive environments that
directly couple students' actions to animations, connections to everyday life,
and efficient calculations so students can focus on the concepts rather than
the math. Like all PhET simulations, these are developed using the results of
education research and feedback from educators, and are tested in student
interviews and classroom studies. This article provides an overview of the PhET
quantum simulations and their development. We also describe research
demonstrating their effectiveness and share some insights about student
thinking that we have gained from our research on quantum simulations.Comment: accepted by American Journal of Physics; v2 includes an additional
study, more explanation of research behind claims, clearer wording, and more
reference
Great Bay Coast Watch: A Citizen Water Monitoring Program Volunteer Water Quality Monitoring Manual, 2004
The Great Bay Coast Watch is citizen volunteers, working within the UNH Cooperative Extension/NH Sea Grant Program, protecting the long-term health and natural resources of New Hampshire’s coastal waters and estuarine systems through monitoring and education projects.
The purpose of this document is to present step-by-step instructions for conducting water quality testing in support of the Great Bay Coast Watch (GBCW)
Searching for dark matter isocurvature initial conditions with N-body Simulations
Small fraction of isocurvature perturbations may exist and correlate with
adiabatic perturbations in the primordial perturbations. Naively switching off
isocurvature perturbations may lead to biased results. We study the effect of
dark matter isocurvature on the structure formation through N-body simulations.
From the best fit values, we run four sets of simulation with different initial
conditions and different box sizes. We find that, if the fraction of dark
matter isocurvature is small, we can not detect its signal through matter power
spectrum and two point correlation function with large scale survey. However,
the halo mass function can give an obvious signal. Compared to 5% difference on
matter power spectrum, it can get 37% at on halo mass function. This
indicates that future high precise cluster count experiment can give stringent
constraints on dark matter isocurvature perturbations.Comment: 6 pages, 4 figure
Nearby Microlensing Events - Identification of the Candidates for the SIM
The Space Interferometry Mission (SIM) is the instrument of choice when it
comes to observing astrometric microlensing events where nearby, usually
high-proper-motion stars (``lenses''), pass in front of more distant stars
(``sources''). Each such encounter produces a deflection in the source's
apparent position that when observed by SIM can lead to a precise mass
determination of the nearby lens star. We search for lens-source encounters
during the 2005-2015 period using Hipparcos, ACT and NLTT to select lenses, and
USNO-A2.0 to search for the corresponding sources, and rank these by the SIM
time required for a 1% mass measurement.
For Hipparcos and ACT lenses, the lens distance and lens-source impact
parameter are precisely determined so the events are well characterized. We
present 32 candidates beginning with a 61 Cyg A event in 2012 that requires
only a few minutes of SIM time. Proxima Centauri and Barnard's star each
generate several events. For NLTT lenses, the distance is known only to a
factor of 3, and the impact parameter only to 1''. Together, these produce
uncertainties of a factor ~10 in the amount of SIM time required. We present a
list of 146 NLTT candidates and show how single-epoch CCD photometry of the
candidates could reduce the uncertainty in SIM time to a factor of ~1.5.Comment: ApJ accepted, 31 pages (inc. 5 tables), 5 figures. t SIM refine
A Study of Educational Simulations Part I - Engagement and Learning
Interactive computer simulations with complex representations and sophisticated graphics are a relatively new addition to the classroom, and research in this area is limited. We have conducted over 200 individual student interviews during which the students described what they were thinking as they interacted with simulations. These interviews were conducted as part of the research and design of simulations for the Physics Education Technology (PhET) project. PhET is an ongoing project that has developed over 60 simulations for use in teaching physics, chemistry, and physical science. These interviews are a rich source of information about how students interact with computer simulations and what makes an educationally effective simulation. We have observed that simulations can be highly engaging and educationally effective, but only if the student's interaction with the simulation is directed by the student's own questioning. Here we describe our design process, what features are effective for engaging students in educationally productive interactions and the underlying principles which support our empirically developed guidelines. In a companion paper we describe in detail the design features used to create an intuitive simulation for students to use
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