412 research outputs found
An Analysis of Pricing Strategy and Price Dispersion on the Internet
Using prices obtained from shopbots, we test several hypotheses regarding the economics of information and optimal search. We find that price dispersion is positively (negatively) related to product price and the number of sellers in cross-sectional (time series) analysis. Price dispersion increases over time when the sample includes new entrants, but decreases in the absence of entry. Controlling for shipping charges and seller heterogeneity reduces, but does not eliminate, price dispersion. Finally, prices appear to be correlated across products and over time â low price sellers for one product (time period) generally charge low prices for all items (time periods).
Gender and Crime: Addressing Threats to Construct Validity in the Criminological Research
In this article we argue that criminology is in need of a meta-theory that allows for a more complete treatment of the gender-crime relationship We suggest that one such metatheory is Integral Theory Integral Theory challenges disciplinary myopia and opens space for a more complete treatment of complex constructs such as gender We note that criminology would benefit from an ontological and epistemological pluralismthat accommodates the wide range of existing gender theories and recognizes the value of multiple methods designed to test those theories These arguments are supported via an analysis of recent research on the gender-crime relationshi
Ar-40-Ar-39 Age of an Impact-Melt Lithology in Lunar Meteorite Dhofar 961
The Dhofar 961 lunar meteorite was found in 2003 in Oman. It is texturally paired with Dhofar 925 and Dhofar 960 (though Dhofar 961 is more mafic and richer in incompatible elements). Several lines of reasoning point to the South Pole-Aitken Basin (SPA) basin as a plausible source (Figure 2): Mafic character of the melt-breccia lithic clasts consistent the interior of SPA, rules out feldspathic highlands. Compositional differences from Apollo impact-melt groups point to a provenance that is separated and perhaps far distant from the Procellarum KREEP Terrane SPA "hot spots" where Th concentrations reach 5 ppm and it has a broad "background" of about 2 ppm, similar to lithic clasts in Dhofar 961 subsamples If true, impact-melt lithologies in this meteorite may be unaffected by the Imbrium-forming event that is pervasively found in our Apollo sample collection, and instead record the early impact history of the Moon
IU Libraries Discovery Layer Implementation Task Force Progress Report and Notes & Recommendations for Future
In May 2013, the primary public interface for IUCAT transitioned to a new discovery layer interface, powered by the open source web application Blacklight. This document reports on progress and makes recommendations for enabling ongoing system-wide input into the development of the catalog discovery interface through the completion of the upcoming OLE migration project. Appendices include groupsâ charges & memberships, and an annotated version of the original selection rubric notating status of product features.This report was prepared for the IU Council of Head Librarians
Meeting the ISTE Challenge in the Field: An Overview of the First Six Distinguished Achievement Award Winning Programs
The 2002 National Educational Technology Standards (NETS) Distinguished Achievement Awards, sponsored by the International Society for Technology in Education (ISTE), were awarded to six teacher education programs across the United States. The awards recognize institutions that exemplify successful integration of the National Educational Technology Standards for Teachers (NETS[solid dot]T) into teacher education programs. Institutions across the country completed an extensive application process to be selected one of the first six recipients of the ISTE Distinguished Achievement award. This process included online documentation that demonstrated the program\u27s implementation of the NETS[solid dot]T models and practices. This article provides a means of uniting various programs and program developers (teacher educators and instructional technologists) by looking at the most common obstacles they face in the pursuit of appropriate infusion of technology into teacher education programs and workable solutions for overcoming those obstacles
Creative leisure activities, mental health and well-being during 5 months of the COVID-19 pandemic: a fixed effects analysis of data from 3725 US adults
Introduction:
We investigated whether changes in engagement in home-based creative activities were associated with changes in depressive symptoms, anxiety symptoms and life satisfaction during the COVID-19 pandemic, aiming to replicate findings from the UK in a USA sample.
Methods:
3725 adults were included from the COVID-19 Social Study in the USA, a panel study collecting data weekly during the COVID-19 pandemic. We measured engagement in eight types of creative leisure activities on the previous weekday between April and September 2020. Data were analysed using fixed effects regression models.
Results:
Increased time spent gardening was associated with reductions in depressive and anxiety symptoms and enhanced life satisfaction. Spending more time doing woodwork/DIY and arts/crafts were also associated with enhanced life satisfaction. However, more time watching television, films or other similar media (not for information on COVID-19) was associated with increased depressive symptoms. Other creative activities were not associated with mental health or well-being.
Conclusion:
Some findings differ from evidence obtained in the UK, demonstrating the importance of replicating research across countries. Our findings should also be considered when formulating guidelines for future stay-at-home directives, enabling individuals to stay well despite the closure of public resources
Models of Star-Planet Magnetic Interaction
Magnetic interactions between a planet and its environment are known to lead
to phenomena such as aurorae and shocks in the solar system. The large number
of close-in exoplanets that were discovered triggered a renewed interest in
magnetic interactions in star-planet systems. Multiple other magnetic effects
were then unveiled, such as planet inflation or heating, planet migration,
planetary material escape, and even modification of the host star properties.
We review here the recent efforts in modelling and understanding magnetic
interactions between stars and planets in the context of compact systems. We
first provide simple estimates of the effects of magnetic interactions and then
detail analytical and numerical models for different representative scenarii.
We finally lay out a series of future developments that are needed today to
better understand and constrain these fascinating interactions.Comment: 23 pages, 10 figures, accepted as a chapter in the Handbook of
Exoplanet
Who Engaged in Home-Based Arts Activities During the COVID-19 Pandemic? A Cross-Sectional Analysis of Data From 4,731 Adults in the United States
Arts engagement is a health-related behavior that may be influenced by social inequalities. While the COVID-19 pandemic provided new opportunities for some people to engage in the arts, it might have created barriers for others. We aimed to examine whether there was social patterning in home-based arts engagement during the pandemic in the United States, and whether predictors of engagement differed according to the type of arts activity. We included 4,731 adults who participated in the United States COVID-19 Social Study between April and July 2020. Three types of home-based arts engagement were considered: reading for pleasure, arts or crafts activities, and digital arts activities. Using logistic regression models, we tested cross-sectional associations between a broad range of demographic, socioeconomic, psychosocial, and health-related factors as well as adverse events and worries during lockdown and each type of arts engagement. The factors most strongly associated with all three types of arts engagement were social support, social network size, age, race/ethnicity, keyworker status, and experiencing physical or psychological abuse during the pandemic. However, most socioeconomic and health-related factors were not associated with arts engagement, including household income and mental and physical health problems. Overall, our findings indicate that the social gradient in arts engagement was reduced in the first 4 months of the COVID-19 pandemic in the United States. Given the health benefits of arts engagement, the potential diversification of arts audiences during the pandemic is promising for both population-level health and wellbeing and the future of the arts and cultural sector
Phototactic Responses to Ultraviolet and White Light in Various Species of Collembola, Including the Eyeless Species, Folsomia candida
Previous observations have indicated homology in the cellular components between collembolan eyes and the compound eyes of insects. However, behavioral or physiological studies indicating similarities in function are lacking. Collembolan eyes were examined from three species in the Family Isotomidae using scanning electron microscopy. Collembolan eyes are arranged dorsally and laterally on each side of the head in two species, Proisotoma minuta with eight eyes on each side of the head and Folsomia similis with one eye on each side of the head. In both of these species the eyes were located just posterior to the postantennal organ. In Folsomia candida, no external eye structures were detected. These three species were assayed for a series of behavioral preferences using ultraviolet (UV), white light and dark, and temperature conditions. The tests demonstrated that over 76% of all three species, including the eyeless F. Candida, chose white over UV light, over 69% preferred dark over UV, and over 77% favored dark over white light. The results demonstrated that all three species detect both UV and white light and avoid it, preferring cool, dark habitats. From the results of this study, it is hypothesized that F. candida may, in fact, be only âlenslessâ and may be able to detect light by having internal, non-ocular photoreceptors. Further histological studies are needed to investigate this possibility
The Hubble Space Telescope Wide Field Camera 3 Early Release Science data: Panchromatic Faint Object Counts for 0.2-2 microns wavelength
We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early
Release Science (ERS) observations in the Great Observatories Origins Deep
Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, drizzled
mosaics in the UV filters F225W, F275W, and F336W, as well as in the near-IR
filters F098M (Ys), F125W (J), and F160W (H) with 1-2 HST orbits per filter.
Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South
mosaics in the BViz filters, these panchromatic 10-band ERS data cover 40-50
square arcmin at 0.2-1.7 {\mu}m in wavelength at 0.07-0.15" FWHM resolution and
0.090" Multidrizzled pixels to depths of AB\simeq 26.0-27.0 mag (5-{\sigma})
for point sources, and AB\simeq 25.5-26.5 mag for compact galaxies.
In this paper, we describe: a) the scientific rationale, and the data taking
plus reduction procedures of the panchromatic 10-band ERS mosaics; b) the
procedure of generating object catalogs across the 10 different ERS filters,
and the specific star-galaxy separation techniques used; and c) the reliability
and completeness of the object catalogs from the WFC3 ERS mosaics. The
excellent 0.07-0.15" FWHM resolution of HST/WFC3 and ACS makes star- galaxy
separation straightforward over a factor of 10 in wavelength to AB\simeq 25-26
mag from the UV to the near-IR, respectively.Comment: 51 pages, 71 figures Accepted to ApJS 2011.01.2
- âŚ