39,563 research outputs found
Two Boats, Three Summers, Five Universities, One Dozen Instructors, and Sixty-Five Teachers: A Collaborative Oceanography Field Program for Earth Science
A three-day field workshop was an integral component of the graduate-level course entitled, Oceanography, that was offered by Virginia Earth Science Collaborative Project (VESC) to help Virginia educators earn the earth science teaching endorsement. The VESC partner institutions that offered Oceanographngeorge Mason University, James Madison University, the University of Virginia Southwest Center, and Virginia Commonwealth University-lacked direct access to research and education facilities en the coast. The College of William & Mary, another VESC partner, provided this resource through the Virginia Institute of Marine Science’s (VIMS) Eastern Shore Laboratory in Wachapreague, Virginia. The field program agenda and activities were developed and conducted by a team comprised of VESC oceanography faculty, Virginia Sea Grant educators, and a scientist from VIMS. This collaboration resulted in a program design used as the basis for six workshops conducted over three summers. Seventy-nine Virginia middle school and high school science teachers took part in the six workshops, conducted in July of 2005, 2006, and 2007. This article describes the workshop activities and provides perspectives on its design and implementation from the viewpoints of Virginia Sea Grant educators who served as field instructors
RTP control protocol (RTCP) extended report (XR) block for independent reporting of burst/fgp discard metrics
This document defines an RTP Control Protocol (RTCP) Extended Report
(XR) block that allows the reporting of burst/gap discard metrics
independently of the burst/gap loss metrics for use in a range of RTP
applications
The threatened status of restricted-range coral reef fish species
Coral reefs are the most diverse ecosystem in the sea. Throughout the world they are being overfished, polluted and destroyed, placing biodiversity at risk. To date, much of the concern over biodiversity loss has centred on local losses and the possibility of global extinction has largely been discounted. However, recent research has shown that 24% of reef fish species have restricted ranges (< 800 000 km(2)), with 9% highly restricted (< 50 000 km(2)). Restricted-range species are thought to face a greater risk of extinction than more widespread species since local impacts could cause global loss. We searched for information on status in the wild and characteristics of 397 restricted-range reef fish species. Fish body size, habitat requirements and usefulness to people were compared with those of a taxonomically-matched sample of more widespread species. We found that on average species with restricted ranges were significantly smaller (mean total length 19.1 cm versus 24.4 cm), tended to have narrower habitat requirements and were less used by people. Greater habitat specificity will tend to increase extinction risk while, if real, more limited usefulness (equivalent to exploitation) may reduce risk. Fifty-eight percent of restricted-range species were considered common/abundant in the wild and 42% uncommon/rare. Population status and threats to 319 species for which data were available were assessed according to the categories and criteria of the IUCN red list of threatened animals. A number of species were found to be rare, were exploited and had highly restricted ranges overlapping areas where reef degradation is particularly severe, placing them at a high risk of extinction. Five species were listed as Critically Endangered, two of them possibly already extinct in the wild, one as Endangered and 172 as Vulnerable. A further 126 species fell into Lower Risk categories and 11 were considered Data Deficient. Given the intensity of impacts to reefs, the broad geographical areas affected and the large numbers of restricted-range species, global extinctions seem likely. Urgent management action is now crucial for the survival of several species of reef fishes
Fluctuations in Student Understanding of Newton's 3rd Law
We present data from a between-student study on student response to questions
on Newton's Third Law given throughout the academic year. The study, conducted
at Rochester Institute of Technology, involved students from the first and
third of a three-quarter sequence. Construction of a response curve reveals
subtle dynamics in student learning not captured by simple pre/post testing. We
find a a significant positive effect from direct instruction, peaking at the
end of instruction on forces, that diminishes by the end of the quarter. Two
quarters later, in physics III, a significant dip in correct response occurs
when instruction changes from the vector quantities of electric forces and
fields to the scalar quantity of electric potential. Student response rebounds
to its initial values, however, once instruction returns to the vector-based
topics involving magnetic fields.Comment: Proceedings of the 2010 Physics Education Research Conferenc
Electric field induced charge noise in doped silicon: ionization of phosphorus donors
We report low frequency charge noise measurement on silicon substrates with
different phosphorus doping densities. The measurements are performed with
aluminum single electron transistors (SETs) at millikelvin temperatures where
the substrates are in the insulating regime. By measuring the SET Coulomb
oscillations, we find a gate voltage dependent charge noise on the more heavily
doped substrate. This charge noise, which is seen to have a 1/f spectrum, is
attributed to the electric field induced tunneling of electrons from their
phosphorus donor potentials.Comment: 4 page, 3 figure
Colliders and Brane Vector Phenomenology
Brane world oscillations manifest themselves as massive vector gauge fields.
Their coupling to the Standard Model is deduced using the method of nonlinear
realizations of the spontaneously broken higher dimensional space-time
symmetries. Brane vectors are stable and weakly interacting, and therefore
escape particle detectors unnoticed. LEP and Tevatron data on the production of
a single photon in conjunction with missing energy are used to delineate
experimentally excluded regions of brane vector parameter space. The additional
region of parameter space accessible to the LHC as well as a future lepton
linear collider is also determined by means of this process.Comment: 12 pages, 13 figure
The Formation and Fragmentation of Disks around Primordial Protostars
The very first stars to form in the Universe heralded an end to the cosmic
dark ages and introduced new physical processes that shaped early cosmic
evolution. Until now, it was thought that these stars lived short, solitary
lives, with only one extremely massive star, or possibly a very wide binary
system, forming in each dark matter minihalo. Here we describe numerical
simulations that show that these stars were, to the contrary, often members of
tight multiple systems. Our results show that the disks that formed around the
first young stars were unstable to gravitational fragmentation, possibly
producing small binary and higher-order systems that had separations as small
as the distance between the Earth and the Sun.Comment: This manuscript has been accepted for publication in Science. This
version has not undergone final editing. Please refer to the complete version
of record at http://www.sciencemag.org
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