248 research outputs found
The Unusual Spectrum of Comet 96P/Machholz
We report spectra from 3000-5900 A for comet 96P/Machholz, obtained on 2007
Apr 27 UT with the 3-m Shane telescope at Lick Observatory. The spectra are
extremely carbon poor, and show a prominent NH_2 series, but no CN emission.
NH, NH_2, and C_2 gas production rates are (8.36 +/- 2.18)x10^25, (29.88 +/-
3.66)x10^25, and (4.52 +/- 0.61)x10^23 molecules sec^-1, respectively, as
determined from Haser model fits to the data. Upper limits to the gas
production rates for CN and C_3 are 7.5x10^22 and 2.0x10^23, respectively.
Though 96P is depleted in C_2 and C_3 relative to NH, it is even more depleted
in CN than other so-called "carbon-chain depleted" comets.Comment: 14 pages, 4 tables, 2 figures, accepted for publication in ApJ
Counterpoint: The Insurance Institute for Highway Safety Study Actually Found Cities Using Red Light Cameras Had Higher Red Light Running Fatality Rates
In February 2011, the Insurance Institute for Highway Safety (IIHS) disseminated their research study that compared red light running traffic fatality rates between cities that implemented red light camera (RLC) programs with cities that did not. The IIHS researchers concluded cities that used RLCs had a significantly larger percentage reduction in both red light running (RLR) fatality rates and total fatality rates at signalized intersections. Because a previous IIHS study on RLCs was found to use flawed research methods, as well as to incorrectly report findings, the current IIHS RLC analysis is reviewed for adherence to scientific methods. Our review reveals the 2011 IIHS study is logically flawed and violates basic scientific research methods that are required for a study’s findings to be valid. It has neither internal nor external validity. More importantly, the IIHS did not fully explain the results of its analysis. Correctly interpreting its model’s results actually shows that cities using RLCs had an estimated higher rate of red light running fatalities, specifically 25%, than cities that did not use RLCs in the period “after” cameras were used. Further, the IIHS study was only able to make statements suggesting favorable results from the use ofRLCs due to the biased selection ofsampled cities. The red light running fatality rate as well as the total fatality rate at all signalized intersections in cities that used cameras was higher in both the “before” and “after” time periods, which affirms that superior interventions exist. Also, we explain the IIHS’ financial conflict ofinterest regarding photo enforcement
An Update on Red Light Camera Research: The Need for Federal Standards in the Interest of Public Safety
Since publishing our critique of red light camera (RLC) studies in 2008, we have gained increased insights on the controversy over RLCs. Herein we provide additional information on RLCs, and use a question-and-answer format to address frequently asked questions. This update includes the rationale given for ignoring fatalities at RLC sites, the convergence in findings from the National Highway Traffic Safety Administration\u27s compendium of best RLC studies, common violations of research methods in RLC evaluations, the RLC cost-to-benefit implications for motorists, an explanation for the increase in rear-end crashes at RLC sites, and why RLCs may be ineffective in reducing red light running crashes. We conclude with a proposed solution: restoring and improving federal standards through the Manual on Uniform Traffic Control Devices to assure proper intersection engineering prior to consideration of RLCs (even though RLCs are not recognized as an established safety device)
Traffic Signals : Managing our Assets
SCDOT has identified a performance gap in the area of tracking particular equipment from cradle to grave. Unlike many other roadway assets, traffic signal assets are not all installed in the field. Many assets are stored in signal shop
inventories for use in repairing assets when needed. By not accurately accounting for these assets and tracking assets at all times, SCDOT is not providing a complete picture of the traffic signal assets in the State. The focus of this project was the performance gap identified above, the tracking of equipment from purchase to disposal
Ectopic Expression of Vaccinia Virus E3 and K3 Cannot Rescue Ectromelia Virus Replication in Rabbit RK13 Cells
Citation: Hand, E. S., Haller, S. L., Peng, C., Rothenburg, S., & Hersperger, A. R. (2015). Ectopic Expression of Vaccinia Virus E3 and K3 Cannot Rescue Ectromelia Virus Replication in Rabbit RK13 Cells. Plos One, 10(3), 15. doi:10.1371/journal.pone.0119189As a group, poxviruses have been shown to infect a wide variety of animal species. However, there is individual variability in the range of species able to be productively infected. In this study, we observed that ectromelia virus (ECTV) does not replicate efficiently in cultured rabbit RK13 cells. Conversely, vaccinia virus (VACV) replicates well in these cells. Upon infection of RK13 cells, the replication cycle of ECTV is abortive in nature, resulting in a greatly reduced ability to spread among cells in culture. We observed ample levels of early gene expression but reduced detection of virus factories and severely blunted production of enveloped virus at the cell surface. This work focused on two important host range genes, named E3L and K3L, in VACV. Both VACV and ECTV express a functional protein product from the E3L gene, but only VACV contains an intact K3L gene. To better understand the discrepancy in replication capacity of these viruses, we examined the ability of ECTV to replicate in wild-type RK13 cells compared to cells that constitutively express E3 and K3 from VACV. The role these proteins play in the ability of VACV to replicate in RK13 cells was also analyzed to determine their individual contribution to viral replication and PKR activation. Since E3L and K3L are two relevant host range genes, we hypothesized that expression of one or both of them may have a positive impact on the ability of ECTV to replicate in RK13 cells. Using various methods to assess virus growth, we did not detect any significant differences with respect to the replication of ECTV between wild-type RK13 compared to versions of this cell line that stably expressed VACV E3 alone or in combination with K3. Therefore, there remain unanswered questions related to the factors that limit the host range of ECTV
'If You Desire to Enjoy Life, Avoid Unpunctual People': Women, Timetabling and Domestic Advice, 1850–1910
In the second half of the nineteenth century domestic advice manuals applied the language of modern, public time management to the private sphere. This article uses domestic advice and cookery books, including Isabella Beeton's Book of Household Management, to argue that women in the home operated within multiple, overlapping temporalities that incorporated daily, annual, linear and cyclical scales. I examine how seasonal and annual timescales coexisted with the ticking clock of daily time as a framework within which women were instructed to organize their lives in order to conclude that the increasing concern of advice writers with matters of timekeeping and punctuality towards the end of the nineteenth century indicates not the triumph of 'clock time' but rather its failure to overturn other ways of thinking about and using time
Occurrence, function and evolutionary origins of ‘2A-like’ sequences in virus genomes
2A is an oligopeptide sequence mediating a ribosome ‘skipping’ effect, producing an apparent ‘cleavage’ of polyproteins. First identified and characterized in picornaviruses, ‘2A-like’ sequences are found in other mammalian viruses and a wide range of insect viruses. Databases were analysed using a motif conserved amongst 2A/2A-like sequences. The newly identified 2A-like sequences (30 aa) were inserted into a reporter polyprotein to determine their cleavage activity. Our analyses showed that these sequences fall into two categories. The majority mediated very high (complete) cleavage to separate proteins and a few sequences mediated cleavage with lower efficiency, generating appreciable levels of the uncleaved form. Phylogenetic analyses of 2A-like sequences and RNA-dependent RNA polymerases (RdRps) indicated multiple, independent, acquisitions of these sequences at different stages during virus evolution. Within a virus family, 2A sequences are (probably) homologous, but diverge due to other evolutionary pressures. Amongst different families, however, 2A/2A-like sequences appear to be homoplasic
- …