351 research outputs found
Biotechnology: A Necessity for Science Literacy.
A hands-on semester-long course in biotechnology for middle school students, high school students, or college students provides a way to learn about new technologies and can be coupled with assignments that provoke their thinking about the ethical and social ramifications of the field’s advances
Science Inquiry at the Illinois Mathematics and Science Academy
Located in Aurora, Illinois, the Illinois Mathematics and Science Academy (IMSA) is an internationally recognized, pioneering educational institution created by the State to develop talent and stimulate excellence in teaching and learning in mathematics, science, and technology (Marshall 2002). IMSA\u27s advanced residential college preparatory program enrolls 650 academically talented Illinois students in grades 10—12. Students come from across the state of Illinois, applying as freshmen to enter the Academy in the sophomore class. The student body is 50% female and 50% male. Of the 2003-04 student profile, 69% of students were from the Chicago/Metropolitan area and 31% were from other areas of Illinois. Ethnic demographics for this group were 49% White, 35% Asian, 8% African American, 4% Latino, 3% bi-racial/multi-ethnic, and fewer than 1% Native American. IMSA utilizes an accomplishment- based selection process that incorporates performance on projects as well as participation or leadership in extracurricular activities, together with more traditional indicators of achievement, such as test scores and grades. Typically, 10—15% of the entering class will be eighth graders, although younger students have been admitted occasionally
Student Inquiry and Research: Developing Students\u27 Authentic Inquiry Skills
Established by the state of Illinois in 1985 to develop talent and leadership in science, technology, engineering, and mathematics (STEM), the Illinois Mathematics and Science Academy (IMSA) has become an internationally recognized educational learning laboratory that inspires, challenges, and nurtures talented students. Our advanced, residential, college preparatory program prepares 650 talented Illinois students in grades 10, 11, and 12 to become scholars, researchers, and entrepreneurs. Toward this end, we find that about 80% of our graduates obtain STEM bachelor\u27s degrees.
IMSA has a long history of supporting, nurturing, and promoting high school student participation in research through our academic curriculum and the Student Inquiry and Research (SIR) program. In 2008, we completed our 22nd year as a math and science academy; for 20 of these years we have had a student research program that now numbers approximately 3,300 cumulative student participants. The SIR program supports student research not only in science, technology, engineering, and mathematics (STEM) fields (about 75% of participants), but also in the fine arts fields
The costs of infection and resistance as determinants of West Nile virus susceptibility in Culex mosquitoes
<p>Abstract</p> <p>Background</p> <p>Understanding the phenotypic consequences of interactions between arthropod-borne viruses (arboviruses) and their mosquito hosts has direct implications for predicting the evolution of these relationships and the potential for changes in epidemiological patterns. Although arboviruses are generally not highly pathogenic to mosquitoes, pathology has at times been noted. Here, in order to evaluate the potential costs of <it>West Nile virus </it>(WNV) infection and resistance in a primary WNV vector, and to assess the extent to which virus-vector relationships are species-specific, we performed fitness studies with and without WNV exposure using a highly susceptible <it>Culex pipiens </it>mosquito colony. Specifically, we measured and compared survival, fecundity, and feeding rates in bloodfed mosquitoes that were (i) infected following WNV exposure (susceptible), (ii) uninfected following WNV exposure (resistant), or (iii) unexposed.</p> <p>Results</p> <p>In contrast to our previous findings with a relatively resistant <it>Cx. tarsalis </it>colony, WNV infection did not alter fecundity or blood-feeding behaviour of <it>Cx. pipiens</it>, yet results do indicate that resistance to infection is associated with a fitness cost in terms of mosquito survival.</p> <p>Conclusions</p> <p>The identification of species-specific differences provides an evolutionary explanation for variability in vector susceptibility to arboviruses and suggests that understanding the costs of infection and resistance are important factors in determining the potential competence of vector populations for arboviruses.</p
Representations of Coherent and Squeezed States in a -deformed Fock Space
We establish some of the properties of the states interpolating between
number and coherent states denoted by ; among them are the
reproducing of these states by the action of an operator-valued function on (the standard Fock space) and the fact that they can be regarded as
-deformed coherent bound states. In this paper we use them, as the basis of
our new Fock space which in this case are not orthogonal but normalized. Then
by some special superposition of them we obtain new representations for
coherent and squeezed states in the new basis. Finally the statistical
properties of these states are studied in detail.Comment: 13 pages, 4 Figure
Analytic results for Gaussian wave packets in four model systems: II. Autocorrelation functions
The autocorrelation function, A(t), measures the overlap (in Hilbert space)
of a time-dependent quantum mechanical wave function, psi(x,t), with its
initial value, psi(x,0). It finds extensive use in the theoretical analysis and
experimental measurement of such phenomena as quantum wave packet revivals. We
evaluate explicit expressions for the autocorrelation function for
time-dependent Gaussian solutions of the Schrodinger equation corresponding to
the cases of a free particle, a particle undergoing uniform acceleration, a
particle in a harmonic oscillator potential, and a system corresponding to an
unstable equilibrium (the so-called `inverted' oscillator.) We emphasize the
importance of momentum-space methods where such calculations are often more
straightforwardly realized, as well as stressing their role in providing
complementary information to results obtained using position-space
wavefunctions.Comment: 18 pages, RevTeX, to appear in Found. Phys. Lett, Vol. 17, Dec. 200
Mosquitoes Inoculate High Doses of West Nile Virus as They Probe and Feed on Live Hosts
West Nile virus (WNV) is transmitted to vertebrate hosts by mosquitoes as they take a blood meal. The amount of WNV inoculated by mosquitoes as they feed on a live host is not known. Previous estimates of the amount of WNV inoculated by mosquitoes (101.2–104.3 PFU) were based on in vitro assays that do not allow mosquitoes to probe or feed naturally. Here, we developed an in vivo assay to determine the amount of WNV inoculated by mosquitoes as they probe and feed on peripheral tissues of a mouse or chick. Using our assay, we recovered approximately one-third of a known amount of virus inoculated into mouse tissues. Accounting for unrecovered virus, mean and median doses of WNV inoculated by four mosquito species were 104.3 PFU and 105.0 PFU for Culex tarsalis, 105.9 PFU and 106.1 PFU for Cx. pipiens, 104.7 PFU and 104.7 PFU for Aedes japonicus, and 103.6 PFU and 103.4 PFU for Ae. triseriatus. In a direct comparison, in vivo estimates of the viral dose inoculated by Cx. tarsalis were approximately 600 times greater than estimates obtained by an in vitro capillary tube transmission assay. Virus did not disperse rapidly, as >99% of the virus was recovered from the section fed or probed upon by the mosquito. Furthermore, 76% (22/29) of mosquitoes inoculated a small amount of virus (∼102 PFU) directly into the blood while feeding. Direct introduction of virus into the blood may alter viral tropism, lead to earlier development of viremia, and cause low rates of infection in co-feeding mosquitoes. Our data demonstrate that mosquitoes inoculate high doses of WNV extravascularly and low doses intravascularly while probing and feeding on a live host. Accurate estimates of the viral dose inoculated by mosquitoes are critical in order to administer appropriate inoculation doses to animals in vaccine, host competence, and pathogenesis studies
Estimating Nuisance Parameters in Inverse Problems
Many inverse problems include nuisance parameters which, while not of direct
interest, are required to recover primary parameters. Structure present in
these problems allows efficient optimization strategies - a well known example
is variable projection, where nonlinear least squares problems which are linear
in some parameters can be very efficiently optimized. In this paper, we extend
the idea of projecting out a subset over the variables to a broad class of
maximum likelihood (ML) and maximum a posteriori likelihood (MAP) problems with
nuisance parameters, such as variance or degrees of freedom. As a result, we
are able to incorporate nuisance parameter estimation into large-scale
constrained and unconstrained inverse problem formulations. We apply the
approach to a variety of problems, including estimation of unknown variance
parameters in the Gaussian model, degree of freedom (d.o.f.) parameter
estimation in the context of robust inverse problems, automatic calibration,
and optimal experimental design. Using numerical examples, we demonstrate
improvement in recovery of primary parameters for several large- scale inverse
problems. The proposed approach is compatible with a wide variety of algorithms
and formulations, and its implementation requires only minor modifications to
existing algorithms.Comment: 16 pages, 5 figure
Entropic descriptor of a complex behaviour
We propose a new type of entropic descriptor that is able to quantify the
statistical complexity (a measure of complex behaviour) by taking
simultaneously into account the average departures of a system's entropy S from
both its maximum possible value Smax and its minimum possible value Smin. When
these two departures are similar to each other, the statistical complexity is
maximal. We apply the new concept to the variability, over a range of length
scales, of spatial or grey-level pattern arrangements in simple models. The
pertinent results confirm the fact that a highly non-trivial, length-scale
dependence of the entropic descriptor makes it an adequate complexity-measure,
able to distinguish between structurally distinct configurational macrostates
with the same degree of disorder.Comment: 14 pages, 7 figures, extended versio
- …