1,083 research outputs found
First Steps Toward Change in Teacher Preparation for Elementary Science
Unless introductory undergraduate science classes for prospective elementary teachers actively incorporate the philosophy of inquiry-based learning called for in K-l2 science education refom little will change in elementary science education. Thus, at James Madison University, we have developed a new integrated science core curriculum called Understanding our World [1]. This course sequence was not only designed to fulfill general education science requirements. but also to focus on content areas our students will need to know as teachers. The objectives of these courses are based on the National Science Education Standards and Virginia’s Science Standards of Learning, including earth and space science, chemistry, physics, life sciences, and environmental science [2,3]. As an integrated package, this course sequence addresses basic science content, calculation skills, the philosophy and history of science, the process of how science is done, the role of science in society, and applications of computers and technology in science. Keeping in mind that students tend to teach in the same way they were taught, Understanding our World core classes embrace the concepts associated with reform in elementary math and science
State of the art, gaps and future perspectives on common kestrel ecotoxicology
Anthropogenic activities have caused a steady decline of common kestrel (Falco tinnunculus) since the 1980 s. Effects, especially sublethal effects of contaminants, need to be investigated to ensure the conservation of this species. Data about countries, biological material, contaminants classes, and methodological approaches were collected from scientific publications to highlight gaps on common kestrel toxicology and ecotoxicology. We found that most studies have been conducted in Europe and in the field, underlining a lack of in vitro studies. The studies investigated mainly contaminant levels, while sublethal effects, evaluation of emerging contaminants and use of non-invasive or low-invasive samples were scarce. This work shows important gaps on toxicological status of the common kestrel, highlighting the importance of developing a non-lethal approach that combines responses at different levels of biological organization, as well as data on chemical contamination and on the environment in which the different populations inhabit
Biodiversity evaluation: From endorsed indexes to inclusion of a pollinator indicator
There is increasing interest in evaluating biodiversity to preserve ecosystem services. Researchers can sustain policymakers by providing tools, such as indexes and indicators, that need constant implementation to become accepted standards. Implementation may vary from re-evaluation of existing indicators to introduction of new ones based on emerging threats to biodiversity. With the aim of contributing to the compelling need to estimate and counterbalance pollinator loss, we screened existing bioindicators. We first selected indexes/indicators applied to agricultural contexts and concurrently endorsed by a regulatory agency. We then extended our analysis to indexes/indicators based on arthropod taxa and formally recognized at least by national bodies. Our procedure identified a combination of surveys of various animal taxa and remote landscape analyses (e.g., using a GIS and other cartographic tools). When the animals are arthropods, most indexes/indicators can only address confined environments (e.g., grasslands, riversides). Indicator strength was improved by the simultaneous inclusion of biotic and abiotic components. Pollinator sensitivity to changes at micro-habitat level is widely appreciated and may help distinguish agricultural practices. A biodiversity index based on pollinators, including a wide monitoring scheme supplemented by citizen science, is currently fostered at the European level. The results obtained using such an index may finally enable focusing of strategic funding. Our analysis will help to reach this goal
What is the evidence for giving chemoprophylaxis to children or students attending the same preschool, school or college as a case of meningococcal disease?
We performed a systematic literature review to assess the effectiveness of chemoprophylaxis for contacts of sporadic cases of invasive meningococcal disease (IMD) in educational settings. No studies directly compared IMD risk in contacts with/without chemoprophylaxis. However, compared to the background incidence, an elevated IMD risk was identified in settings without a general recommendation for chemoprophylaxis in pre-schools [pooled risk difference (RD) 58·2/10⁵, 95% confidence interval (CI) 27·3-89·0] and primary schools (pooled RD 4·9/10⁵, 95% CI 2·9-6·9) in the ~30 days after contact with a sporadic IMD case, but not in other educational settings. Thus, limited but consistent evidence suggests the risk of IMD in pre-school contacts of sporadic IMD cases is significantly increased above the background risk, but lower than in household contacts (pooled RD for household contacts with no chemoprophylaxis vs. background incidence: 480·1/10⁵, 95% CI 321·5-639·9). We recommend chemoprophylaxis for pre-school contacts depending on an assessment of duration and closeness of contact
Atomic Hole Doping of Graphene
Graphene is an excellent candidate for the next generation of electronic
materials due to the strict two-dimensionality of its electronic structure as
well as the extremely high carrier mobility. A prerequisite for the development
of graphene based electronics is the reliable control of the type and density
of the charge carriers by external (gate) and internal (doping) means. While
gating has been successfully demonstrated for graphene flakes and epitaxial
graphene on silicon carbide, the development of reliable chemical doping
methods turns out to be a real challenge. In particular hole doping is an
unsolved issue. So far it has only been achieved with reactive molecular
adsorbates, which are largely incompatible with any device technology. Here we
show by angle-resolved photoemission spectroscopy that atomic doping of an
epitaxial graphene layer on a silicon carbide substrate with bismuth, antimony
or gold presents effective means of p-type doping. Not only is the atomic
doping the method of choice for the internal control of the carrier density. In
combination with the intrinsic n-type character of epitaxial graphene on SiC,
the charge carriers can be tuned from electrons to holes, without affecting the
conical band structure
Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision
We report a measurement of the positive muon lifetime to a precision of 1.0
parts per million (ppm); it is the most precise particle lifetime ever
measured. The experiment used a time-structured, low-energy muon beam and a
segmented plastic scintillator array to record more than 2 x 10^{12} decays.
Two different stopping target configurations were employed in independent
data-taking periods. The combined results give tau_{mu^+}(MuLan) =
2196980.3(2.2) ps, more than 15 times as precise as any previous experiment.
The muon lifetime gives the most precise value for the Fermi constant:
G_F(MuLan) = 1.1663788 (7) x 10^-5 GeV^-2 (0.6 ppm). It is also used to extract
the mu^-p singlet capture rate, which determines the proton's weak induced
pseudoscalar coupling g_P.Comment: Accepted for publication in Phys. Rev. Let
Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant
The mean life of the positive muon has been measured to a precision of 11 ppm
using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which
was surrounded by a scintillator detector array. The result, tau_mu =
2.197013(24) us, is in excellent agreement with the previous world average. The
new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F =
1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of
the positive muon lifetime is needed to determine the nucleon pseudoscalar
coupling g_P.Comment: As published version (PRL, July 2007
Squeezing based on nondegenerate frequency doubling internal to a realistic laser
We investigate theoretically the quantum fluctuations of the fundamental
field in the output of a nondegenerate second harmonic generation process
occuring inside a laser cavity. Due to the nondegenerate character of the
nonlinear medium, a field orthogonal to the laser field is for some operating
conditions indepedent of the fluctuations produced by the laser medium. We show
that this fact may lead to perfect squeezing for a certain polarization mode of
the fundamental field. The experimental feasibility of the system is also
discussed.Comment: 6 pages, 5 figure
Measurement of airborne fission products in Chapel Hill, NC, USA from the Fukushima Dai-ichi reactor accident
We present measurements of airborne fission products in Chapel Hill, NC, USA,
from 62 days following the March 11, 2011, accident at the Fukushima Dai-ichi
nuclear power plant. Airborne particle samples were collected daily in air
filters and radio-assayed with two high-purity germanium (HPGe) detectors. The
fission products I-131 and Cs-137 were measured with maximum activities of 4.2
+/- 0.6 mBq/m^3 and 0.42 +/- 0.07 mBq/m^3 respectively. Additional activity
from I-131, I-132, Cs-134, Cs-136, Cs-137 and Te-132 were measured in the same
air filters using a low-background HPGe detector at the Kimballton Underground
Research Facility (KURF).Comment: 10 pages, 4 figure
NEMO-SN1 (Western Ionian Sea, off Eastern Sicily): A Cabled Abyssal Observatory with Tsunami Early Warning Capability
The NEMO-SN1 (NEutrino Mediterranean Observatory - Submarine
Network 1) seafloor observatory is located in the central
Mediterranean, Western Ionian Sea, off Eastern Sicily Island (Southern
Italy) at 2100 m water depth, 25 km from the harbour of the city of
Catania. It is a prototype of cabled deep-sea multiparameter
observatory, and the first operating with real-time data transmission in
Europe since 2005. NEMO-SN1 is also the first-established node of
EMSO (European Multidisciplinary Seafloor Observatory,
http://emso-eu.org), one of the European large-scale research
infrastructures. EMSO will address long-term monitoring of
environmental processes related to marine ecosystems, climate change
and geo-hazards. NEMO-SN1 will perform geophysical and
environmental long-term monitoring by acquiring seismological,
geomagnetic, gravimetric, accelerometric, physico-oceanographic,
hydro-acoustic, bio-acoustic measurements to study earthquake and
tsunami generation, and to characterize ambient noise which includes
marine mammal sounds, and environmental and anthropogenic sources.
NEMO-SN1 is also equipped with a prototype tsunami detector, based
on the simultaneous measurement of the seismic and bottom pressure
signals and a new high performance tsunami detection algorithm.
NEMO-SN1 will be a permanent tsunami early warning node in
Western Ionian Sea, an area where very destructive earthquakes have
occurred in the past, some of them tsunamigenic (e.g., 1693, M=7.5;
1908, M=7.4).
Another important feature of NEMO-SN1 is the installation of a low
frequency-high sensibility hydrophone and two (scalar and vector,
respectively) magnetometers. The objective is to improve the tsunami
detection capability of SN1 through the recognition of tsunami-induced
hydro-acoustic and electro-magnetic precursors.SubmittedRhodes, Greece3A. Ambiente Marinorestricte
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