2,317 research outputs found
Investigating students seriousness during selected conceptual inventory surveys
Conceptual inventory surveys are routinely used in education research to
identify student learning needs and assess instructional practices. Students
might not fully engage with these instruments because of the low stakes
attached to them. This paper explores tests that can be used to estimate the
percentage of students in a population who might not have taken such surveys
seriously. These three seriousness tests are the pattern recognition test, the
easy questions test, and the uncommon answers test. These three tests are
applied to sets of students who were assessed either by the Force Concept
Inventory, the Conceptual Survey of Electricity and Magnetism, or the Brief
Electricity and Magnetism Assessment. The results of our investigation are
compared to computer simulated populations of random answers.Comment: 8 pages; submitted to Phys Rev PE
Raccoons: Wildlife Damage Management Series
Raccoons (Procyon lotor) are found across the United States largely due to their excellent ability to adapt and take advantage of new habitats. Raccoons, although not native to Utah, are abundant throughout much of the state. They are most commonly found in wooded areas along rivers, marshes or lakes. In urban areas, raccoons will make dens in attics, chimneys, under houses, in abandoned buildings, and in woodpiles
Central European foreign exchange markets: a cross-spectral analysis of the 2007 financial crisis
This paper investigates co-movements between currency markets of Czech Republic, Poland, Hungary, Slovakia and the Euro in the year following the drying up of money markets in August 2007. The paper shows that assessing the degree of foreign currency co-movement by correlation can lead to concluding, erroneously, that financial contagion has not occurred. Using cross-spectral methods, the paper shows that defining contagion as changes in the structure of co-movements of asset prices encompasses more of the complex nature of exchange rate dynamics. What is shown is that, following August 2007, there is increased in the intensity of co-movements, but non-linearly. Focusing on the activities of a mix of banks and currency managers, it is suggested that changes in the structure of currency interaction present an unfavourable view of the contagion experienced by at least three of these currencies
Partisan Asymmetries in Online Political Activity
We examine partisan differences in the behavior, communication patterns and
social interactions of more than 18,000 politically-active Twitter users to
produce evidence that points to changing levels of partisan engagement with the
American online political landscape. Analysis of a network defined by the
communication activity of these users in proximity to the 2010 midterm
congressional elections reveals a highly segregated, well clustered partisan
community structure. Using cluster membership as a high-fidelity (87% accuracy)
proxy for political affiliation, we characterize a wide range of differences in
the behavior, communication and social connectivity of left- and right-leaning
Twitter users. We find that in contrast to the online political dynamics of the
2008 campaign, right-leaning Twitter users exhibit greater levels of political
activity, a more tightly interconnected social structure, and a communication
network topology that facilitates the rapid and broad dissemination of
political information.Comment: 17 pages, 10 figures, 6 table
Tomorrow\u27s banking: Four perspectives
Illustration not included in Web versio
Geometric and dynamic perspectives on phase-coherent and noncoherent chaos
Statistically distinguishing between phase-coherent and noncoherent chaotic
dynamics from time series is a contemporary problem in nonlinear sciences. In
this work, we propose different measures based on recurrence properties of
recorded trajectories, which characterize the underlying systems from both
geometric and dynamic viewpoints. The potentials of the individual measures for
discriminating phase-coherent and noncoherent chaotic oscillations are
discussed. A detailed numerical analysis is performed for the chaotic R\"ossler
system, which displays both types of chaos as one control parameter is varied,
and the Mackey-Glass system as an example of a time-delay system with
noncoherent chaos. Our results demonstrate that especially geometric measures
from recurrence network analysis are well suited for tracing transitions
between spiral- and screw-type chaos, a common route from phase-coherent to
noncoherent chaos also found in other nonlinear oscillators. A detailed
explanation of the observed behavior in terms of attractor geometry is given.Comment: 12 pages, 13 figure
High connectivity among locally adapted populations of a marine fish (Menidia menidia)
Author Posting. © Ecological Society of America, 2010. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 91 (2010): 3526â3537, doi:10.1890/09-0548.1.Patterns of connectivity are important in understanding the geographic scale of local adaptation in marine populations. While natural selection can lead to local adaptation, high connectivity can diminish the potential for such adaptation to occur. Connectivity, defined as the exchange of individuals among subpopulations, is presumed to be significant in most marine species due to life histories that include widely dispersive stages. However, evidence of local adaptation in marine species, such the Atlantic silverside, Menidia menidia, raises questions concerning the degree of connectivity. We examined geochemical signatures in the otoliths, or ear bones, of adult Atlantic silversides collected in 11 locations along the northeastern coast of the United States from New Jersey to Maine in 2004 and eight locations in 2005 using laser ablation inductively coupled plasma mass spectrometry (ICP-MS) and isotope ratio monitoring mass spectrometry (irm-MS). These signatures were then compared to baseline signatures of juvenile fish of known origin to determine natal origin of these adult fish. We then estimated migration distances and the degree of mixing from these data. In both years, fish generally had the highest probability of originating from the same location in which they were captured (0.01â0.80), but evidence of mixing throughout the sample area was present. Furthermore, adult M. menidia exhibit highly dispersive behavior with some fish migrating over 700 km. The probability of adult fish returning to natal areas differed between years, with the probability being, on average, 0.2 higher in the second year. These findings demonstrate that marine species with largely open populations are capable of local adaptation despite apparently high gene flow.This work was funded by the National Science Foundation
(grant OCE-0425830 to D. O. Conover and grant OCE-
0134998 to S. R. Thorrold) and the New York State
Department of Environmental Conservation
The Association of Early Dietary Supplementation with Vitamin E with the Incidence of Ulcerative Dermatitis in Mice on a C57BL/6 Background
The purpose of this study was to ascertain if prophylactic ingestion of a diet rich in vitamin E would prevent or impede the development of ulcerative dermatitis in mice on a C57BL/6 background. Mice were fed after weaning a standard mouse diet, vitamin E (99 IU/kg), or a mouse diet fortified with vitamin E (3000 IU/ kg). Cases of ulcerative dermatitis were recorded by individuals (i.e. aware of) the diet assignment. The incidence of ulcerative dermatitis in a retrospective cohort of mice on standard diet was compared with the group on the diet fortified with vitamin E. Age was associated with ulcerative dermatitis in standard diet and vitamin E fortified diet groups, r = 0.43, p-value < 0.0001 and r = 0.18, p-value < 0.02, respectively. The average age of incidence for ulcerative dermatitis in the mice fed the standard diet was 89 weeks and for the mice fed the vitamin E diet it was 41 weeks. The unadjusted odds ratio comparing the incidence of ulcerative dermatitis between the two diet groups was 4.6 with a 95% confidence interval of (2.44, 8.58), x2 p-value < 0.0001. Therefore, there was an association between the diets and ulcerative dermatitis, with the mice on the vitamin E fortified diet having almost five times the odds of having ulcerative dermatitis compared with mice on the standard diet. Incidence of ulcerative dermatitis was not influenced by sex or genotype. Our study results show that a diet fortified in vitamin E initiated at weaning does not prevent or impede the development of ulcerative dermatitis in mice on a C57BL/6 background and on the contrary accelerate development when administered to young mice.
Training tomorrow\u27s specialists in wildlife damage management
In 1990, Utah State University (USU) established a U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Animal Damage Control (ADC)-funded center dedicated to research, education, and extension in wildlife damage management. USU\u27 s Program in Wildlife Damage Management is designed to increase appreciation for wildlife damage management among wildlife professionals, provide superior training for future practitioners of wildlife damage management through education and innovative research, and create better public understanding of the role of wildlife damage management in today\u27s society
- âŠ