468 research outputs found
The effects of 3-dimensional CADD modeling software on the development of the spatial ability of ninth grade technology discovery students
The purpose of this quantitative study was to determine if there is a difference in the development of spatial abilities of ninth grade Technology Discovery students in Mississippi as measured by the Purdue Visualization of Rotations Test. Students experienced one of three differing instructional methods utilizing Pro/Desktop® 3-D CADD solid modeling software. Participants were students in Mississippi schools operating on a 4 x 4 block schedule during either fall or spring semesters during the 2005-2006 school year, and a control group of students whose schools did not offer CADD. Instructional material designed by the researcher was used for two instructional treatment methods, with existing instructional materials available for the software were used in the third instructional method. Demographic information was collected for students from 14 schools in the study. The primary research question asked if differences existed by instructional treatment method when spatial ability pretest scores, gender, ethnicity, co-registration in art, and co-registration in geometry were controlled. Analysis of Covariance was conducted to analyze the data for this research question, using the pretest as the covariate and instructional method as the fixed factor. The dependent variable was the posttest score. The other independent variables of gender, ethnicity, and co-enrollment in art and/or geometry were included in analysis. No affects concerning these additional variables was found. A statistically significant difference existed concerning the method used to instruct students on the use of 3-D CADD modeling software. The instructional consisting of method of teacher-lead instruction using the software in a design lesson, followed by student-directed modular instruction, was found to be effective. These lessons included 3-D physical models manipulated by the teacher and students. The group of students taught using this method had higher mean posttest scores than students instructed with other methods. The other instructional methods did not significantly affect student achievement on the test of spatial ability
A Precision Calculation of the Next-to-Leading Order Energy-Energy Correlation Function
The O(alpha_s^2) contribution to the Energy-Energy Correlation function (EEC)
of e+e- -> hadrons is calculated to high precision and the results are shown to
be larger than previously reported. The consistency with the leading logarithm
approximation and the accurate cancellation of infrared singularities exhibited
by the new calculation suggest that it is reliable. We offer evidence that the
source of the disagreement with previous results lies in the regulation of
double singularities.Comment: 6 pages, uuencoded LaTeX and one eps figure appended Complete paper
as PostScript file (125 kB) available at:
http://www.phys.washington.edu/~clay/eecpaper1/paper.htm
Math and Coding Connections in Elementary
In this session, participants learn ways to use coding tools in elementary classrooms to provide engaging and motivating contexts for students to develop and use mathematical and computational reasoning. Integrating technology to support mathematics learning in meaningful ways is often challenging, and discussions in this session will emphasize the synergies among technology, coding, and mathematics for supporting skills with coding tools
Chemical imaging of single catalyst particles with scanning μ-XANES-CT and μ-XRF-CT
The physicochemical state of a catalyst is a key factor in determining both activity and selectivity; however these materials are often not structurally or compositionally homogeneous. Here we report on the 3-dimensional imaging of an industrial catalyst, Mo-promoted colloidal Pt supported on carbon. The distribution of both the active Pt species and Mo promoter have been mapped over a single particle of catalyst using microfocus X-ray fluorescence computed tomography. X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure revealed a mixed local coordination environment, including the presence of both metallic Pt clusters and Pt chloride species, but also no direct interaction between the catalyst and Mo promoter. We also report on the benefits of scanning μ-XANES computed tomography for chemical imaging, allowing for 2- and 3-dimensional mapping of the local electronic and geometric environment, in this instance for both the Pt catalyst and Mo promoter throughout the catalyst particle
Cancer Cell-Extrinsic Roles for the Androgen Receptor in Prostate Cancer
Given the central role of the androgen receptor (AR) in prostate cancer cell biology, AR-targeted therapies have been the backbone of prostate cancer treatment for over 50 years. New data indicate that AR is expressed in additional cell types within the tumor microenvironment. Moreover, targeting AR for the treatment of prostate cancer has established side effects such as bone complications and an increased risk of developing cardiometabolic disease, indicating broader roles for AR. With the advent of novel technologies, such as single-cell approaches and advances in preclinical modeling, AR has been identified to have clinically significant functions in other cell types. In this mini-review, we describe new cancer cell-extrinsic roles for AR within the tumor microenvironment as well as systemic effects that collectively impact prostate cancer progression and patient outcomes
Versatile regularisation toolkit for iterative image reconstruction with proximal splitting algorithms
Ill-posed image recovery requires regularisation to ensure stability. The presented open-source regularisation toolkit consists of state-of-the-art variational algorithms which can be embedded in a plug-and-play fashion
into the general framework of proximal splitting methods. The packaged regularisers aim to satisfy various prior expectations of the investigated objects, e.g., their structural characteristics, smooth or non-smooth surface morphology.
The flexibility of the toolkit helps with the design of more advanced model-based iterative reconstruction methods
for different imaging modalities while operating with simpler building blocks. The toolkit is written for CPU and
GPU architectures and wrapped for Python/MATLAB. We demonstrate the functionality of the toolkit in application
to Positron Emission Tomography (PET) and X-ray synchrotron computed tomography (CT)
Enhanced Nonperturbative Effects in Z Decays to Hadrons
We use soft collinear effective field theory (SCET) to study nonperturbative
strong interaction effects in Z decays to hadronic final states that are
enhanced in corners of phase space. These occur, for example, in the jet energy
distribution for two jet events near E_J=M_Z/2, the thrust distribution near
unity and the jet invariant mass distribution near zero. The extent to which
such nonperturbative effects for different observables are related is
discussed.Comment: 17 pages. Paper reorganized, and more discussion and results include
BRCA1 and BRCA2 mutations in a population-based study of male breast cancer
Background: The contribution of BRCA1 and BRCA2 to the incidence of male breast cancer (MBC)
in the United Kingdom is not known, and the importance of these genes in the increased risk of female
breast cancer associated with a family history of breast cancer in a male first-degree relative is unclear.
Methods: We have carried out a population-based study of 94 MBC cases collected in the UK. We
screened genomic DNA for mutations in BRCA1 and BRCA2 and used family history data from these
cases to calculate the risk of breast cancer to female relatives of MBC cases. We also estimated the
contribution of BRCA1 and BRCA2 to this risk.
Results: Nineteen cases (20%) reported a first-degree relative with breast cancer, of whom seven also
had an affected second-degree relative. The breast cancer risk in female first-degree relatives was 2.4
times (95% confidence interval [CI] = 1.4–4.0) the risk in the general population. No BRCA1 mutation
carriers were identified and five cases were found to carry a mutation in BRCA2. Allowing for a
mutation detection sensitivity frequency of 70%, the carrier frequency for BRCA2 mutations was 8%
(95% CI = 3–19). All the mutation carriers had a family history of breast, ovarian, prostate or
pancreatic cancer. However, BRCA2 accounted for only 15% of the excess familial risk of breast
cancer in female first-degree relatives.
Conclusion: These data suggest that other genes that confer an increased risk for both female and
male breast cancer have yet to be found
New trends in active faulting studies for seismic hazard assessment
Vulnerability to earthquakes increases steadily as urbanization and development expand in areas that are prone to the effects of significant earthquakes. As virtually all of the largest earthquakes of the past decade demonstrated,
the development of large cities in high seismicity areas is often based on an insufficient knowledge or distorted perception of the local seismic hazard, a condition often worsened by the construction of seismically unsafe buildings and infrastructures
Optimizing for periodicity: a model-independent approach to flux crosstalk calibration for superconducting circuits
Flux tunability is an important engineering resource for superconducting
circuits. Large-scale quantum computers based on flux-tunable superconducting
circuits face the problem of flux crosstalk, which needs to be accurately
calibrated to realize high-fidelity quantum operations. Typical calibration
methods either assume that circuit elements can be effectively decoupled and
simple models can be applied, or require a large amount of data. Such methods
become ineffective as the system size increases and circuit interactions become
stronger. Here we propose a new method for calibrating flux crosstalk, which is
independent of the underlying circuit model. Using the fundamental property
that superconducting circuits respond periodically to external fluxes,
crosstalk calibration of N flux channels can be treated as N independent
optimization problems, with the objective functions being the periodicity of a
measured signal depending on the compensation parameters. We demonstrate this
method on a small-scale quantum annealing circuit based on superconducting flux
qubits, achieving comparable accuracy with previous methods. We also show that
the objective function usually has a nearly convex landscape, allowing
efficient optimization
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