Test Mode Familiarity and Performance - Gender and Race Comparisons of Test Scores among Computer-Literate Students in Advanced Information Systems Courses

This investigation compares the effects of test mode, gender and race on paper-based versus computer-based delivery of two high stakes multiple-choice course examinations, Midterm and Final. Computer-literate students in upper-level business courses (n = 144) were randomly assigned to receive both tests either on paper or on computer. There were no significant gender effects, though males scored slightly higher than females on both tests. However, participants who received the tests on paper significantly outscored those who received the tests on computers, but this difference occurred only on the Midterm examination. Most striking, non-white females receiving the computer-based test mode scored lowest on the Midterm examination but then scored highest on the Final; all other groups maintained their relative positions from Midterm to Final. It was concluded that test mode familiarity does impact test performance. The results suggest that even computer-literate students in advanced Information Systems classes should practice using mock computer exams before taking high stakes computer-based tests, and that test mode familiarity affected non-white females most

Achievement Predictors for a Computer-Applications Module Delivered Online

The program evaluation compared student achievement and self-report data in two types of learning environments - a traditional classroom environment and an online learning environment to examine the comparative effectiveness of online delivery, to identify characteristics of successful and unsuccessful distance learning students, and to gauge degree of satisfaction with online delivery. Undergraduate students (N = 93) enrolled in four sections of Business 100, Computer Fundamentals, were assigned by section to complete a 4-weeks long spreadsheet module either in class (control) or online (experimental). The online instruction was delivered via a website and was supplemented with e-mail and listserv discussion. Post test findings revealed no significant differences in knowledge gain between the control (M = .75) and online (M = .77) groups, indicating that this online module was at least as effective as the traditional classroom instruction. Post hoc analysis of achievement data showed that more capable students working online scored significantly better (p \u3c .01) than the more capable control group. Self-report measures compared to achievement indicated that frequent computer users benefited most from online delivery, while frequent computer use was not a factor in the control group\u27s performance. Also competitiveness had a negative correlation with achievement for the online group but not for the control group. In summary, this online instruction provided an effective standardized course delivery. However low-prior knowledge students who are less frequent computer users were not served well by this online instruction

SN 2007uy - metamorphosis of an aspheric Type Ib explosion

The supernovae of Type Ibc are rare and the detailed characteristics of these explosions have been studied only for a few events. Unlike Type II SNe, the progenitors of Type Ibc have never been detected in pre-explosion images. So, to understand the nature of their progenitors and the characteristics of the explosions, investigation of proximate events are necessary. Here we present the results of multi-wavelength observations of Type Ib SN 2007uy in the nearby ($\sim$ 29.5 Mpc) galaxy NGC 2770. Analysis of the photometric observations revealed this explosion as an energetic event with peak absolute R band magnitude $-18.5\pm0.16$, which is about one mag brighter than the mean value ($-17.6\pm0.6$) derived for well observed Type Ibc events. The SN is highly extinguished, E(B-V) = 0.63$\pm$0.15 mag, mainly due to foreground material present in the host galaxy. From optical light curve modeling we determine that about 0.3 M$_{\odot}$ radioactive $^{56}$Ni is produced and roughly 4.4 M$_{\odot}$ material is ejected during this explosion with liberated energy $\sim 15\times10^{51}$ erg, indicating the event to be an energetic one. Through optical spectroscopy, we have noticed a clear aspheric evolution of several line forming regions, but no dependency of asymmetry is seen on the distribution of $^{56}$Ni inside the ejecta. The SN shock interaction with the circumburst material is clearly noticeable in radio follow-up, presenting a Synchrotron Self Absorption (SSA) dominated light curve with a contribution of Free Free Absorption (FFA) during the early phases. Assuming a WR star, with wind velocity \ga 10^3 {\rm km s}^{-1}, as a progenitor, we derive a lower limit to the mass loss rate inferred from the radio data as \dot{M} \ga 2.4\times10^{-5} M$_{\odot}$, yr$^{-1}$, which is consistent with the results obtained for other Type Ibc SNe bright at radio frequencies.Comment: 22 pages, 13 figures, accepted for publication in MNRA

Complete Genome Sequence and Methylome Analysis of Micrococcus luteus SA211, a Halophilic, Lithium-Tolerant Actinobacterium from Argentina

Micrococcus luteus has been found in a wide range of habitats. We report the complete genome sequence and methylome analysis of strain SA211 isolated from a hypersaline, lithium-rich, high-altitude salt flat in Argentina with single-molecule real-time sequencing.Fil: Martínez, Fabiana Lilian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. University of Maryland; Estados UnidosFil: Anton, B. P.. New England Biolabs; Estados UnidosFil: DasSarma, P.. University of Maryland; Estados UnidosFil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Irazusta, Verónica Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Roberts, Roy. New England Biolabs; Estados UnidosFil: DasSarma, S.. University of Maryland; Estados Unido

Linking Adult Reproduction and Larval Density of Invasive Carp in a Large River

Eeotogists increasingly recognize the need to understand how landscapes ami food webs interact. Reservoir ecosystems are heavily subsidized by nutrients and detritus from surrounding watersheds, and ofren contain abundant populations of gizzard shad, an omnivorous ftsh that consumes plankton and detritus. Gizzard shad link terrestrial landscapes ami pelagic reservoir food webs by consuming detritus, translocating nutrients from sedimctn detritus to the water column, and consuming zooplaukton. The abundance of gizzard shad increases with watershed agricuhuralization, most likely through n variety oj mechanisms npeniting on ttuvat and adult life stages. Gizzard shad have myriad effects on reservoirs, including impacts on nutrients, phytoplankton, zooplankton, and fish, and many of their effects vary with ecosystem productivity (i.e., watershed land use). Interactive feedbacks among watersheds, gizzard shad populations, and reservoir food webs operate to maintain dominance of gizzard shad in highly productive systems. Thus, effective stewardship of reservoir ecosystems must incorporate both watershed and food-web perspective

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology