Early changes in gradation styles and rates on Mars

The wide annulus of massifs and knobs of Isidis and Argyre provided sufficiently large areas for meaningful crater statistics of large craters. Counts were made over adjacent and nested areas in order to test consistency and to derive relative age of each basin. Within the Isidis annulus, charateristic terrains provided counting areas for dating contrasting surface process: channeled hummocky terrain, etched terrains, and intermassif channeled plains. The channeled hummocky terrain contains a high channel density of narrow valley networks cutting both primary Isidis features and old craters. The etched terrains represent a broad region outside the inner high relief massifs of southwestern Isidis where numerous irregular plateaus, mesas, and relict craters indicate a different style of erosion. The intermassif channeled plains occur along the inner mountainous ring. Shallow meandering channels form a large integrated drainage system that is linked to numerous smaller intermountainous basins. These ponds and interconnected tributaries extend beyond the primary inner massif ring through broad canyons

The Potential Role of Local Ethical Committees in the Moderation of Experiments on Animals in Britain

Scientists working with laboratory animals in Britain are made aware forcibly that a severe ethical dilemma surrounds using animals in experiments. Certain vociferous sections of the community press the issue on the general public\u27s attention, and media sources tend to propagate views expressed by the most extreme parties while neglecting coverage of mature, rational opinions. It is, perhaps, no bad thing for the scientific community to be frequently reminded to take a responsible attitude to the use of animals. Still, recent overt, even illegal, activity on the part of extremist animal protectionist groups has encouraged a regrettable polarization of viewpoints, with some scientific institutions seeking to withdraw still further from public scrutiny and accountability

To be or not to be Smoke Free: An Analysis of the University of Alaska Anchorage Peer Institutions Smoking and Tobacco Policies

Presented to the Faculty of the University of Alaska Anchorage in partial fulfillment for the Requirements for the Degree of MASTER OF PUBLIC HEALTHMore colleges and universities are adopting smoke-and tobacco-free policies, yet no literature exists on how types of enforcement protocols aide in policy success. The goal of this study was to assess the comprehensive smoke- and tobacco-free policies of the University of Alaska Anchorage’s peer and neighboring postsecondary institutions to determine what enforcement type may benefit the university in moving towards a comprehensive smoke-free campus policy. Both quantitative and qualitative methods were used. In particular, content analysis was used to determine each peer institution’s campus tobacco policy and enforcement strategy, while case study analysis was used to assess the effectiveness of different enforcement types. Results show that approximately 52% of UAA peer institutions have either comprehensive tobacco- and smoke-free campus policies. Of the institutions with comprehensive smoke- or tobacco-free campus policies, 57% have hard/strict enforcement protocols. The case study analyses of two smoke/tobacco-free campuses suggested that hard enforcement with set guidelines and a punitive offense system would promote more policy success over soft enforcement, which only provided verbal reprimand. Study findings suggested that a hard enforcement type was the preferred enforcement method of the sample and that a hard enforcement type supported overall policy success. The study recommends adoption of comprehensive smoke- or tobacco-free campus policies, utilization of a pre-implementation preparatory period before adoption of comprehensive smoke-or tobacco-free policy, and inclusion of hard enforcement protocols to the comprehensive smoke- or tobacco-free policy.Abstract / Acknowledgements / List of Tables / List of Figures / Introduction / Background and Literature Review / Methods and Analysis / Results / Discussion / Conclusion and Recommendations / References / Appendice

Genomic stability in response to high versus low linear energy transfer radiation in Arabidopsis thaliana.

Low linear energy transfer (LET) gamma rays and high LET HZE (high atomic weight, high energy) particles act as powerful mutagens in both plants and animals. DNA damage generated by HZE particles is more densely clustered than that generated by gamma rays. To understand the genetic requirements for resistance to high versus low LET radiation, a series of Arabidopsis thaliana mutants were exposed to either 1GeV Fe nuclei or gamma radiation. A comparison of effects on the germination and subsequent growth of seedlings led us to conclude that the relative biological effectiveness (RBE) of the two types of radiation (HZE versus gamma) are roughly 3:1. Similarly, in wild-type lines, loss of somatic heterozygosity was induced at an RBE of about a 2:1 (HZE versus gamma). Checkpoint and repair defects, as expected, enhanced sensitivity to both agents. The "replication fork" checkpoint, governed by ATR, played a slightly more important role in resistance to HZE-induced mutagenesis than in resistance to gamma induced mutagenesis

High atomic weight, high-energy radiation (HZE) induces transcriptional responses shared with conventional stresses in addition to a core "DSB" response specific to clastogenic treatments.

Plants exhibit a robust transcriptional response to gamma radiation which includes the induction of transcripts required for homologous recombination and the suppression of transcripts that promote cell cycle progression. Various DNA damaging agents induce different spectra of DNA damage as well as "collateral" damage to other cellular components and therefore are not expected to provoke identical responses by the cell. Here we study the effects of two different types of ionizing radiation (IR) treatment, HZE (1 GeV Fe(26+) high mass, high charge, and high energy relativistic particles) and gamma photons, on the transcriptome of Arabidopsis thaliana seedlings. Both types of IR induce small clusters of radicals that can result in the formation of double strand breaks (DSBs), but HZE also produces linear arrays of extremely clustered damage. We performed these experiments across a range of time points (1.5-24 h after irradiation) in both wild-type plants and in mutants defective in the DSB-sensing protein kinase ATM. The two types of IR exhibit a shared double strand break-repair-related damage response, although they differ slightly in the timing, degree, and ATM-dependence of the response. The ATM-dependent, DNA metabolism-related transcripts of the "DSB response" were also induced by other DNA damaging agents, but were not induced by conventional stresses. Both Gamma and HZE irradiation induced, at 24 h post-irradiation, ATM-dependent transcripts associated with a variety of conventional stresses; these were overrepresented for pathogen response, rather than DNA metabolism. In contrast, only HZE-irradiated plants, at 1.5 h after irradiation, exhibited an additional and very extensive transcriptional response, shared with plants experiencing "extended night." This response was not apparent in gamma-irradiated plants

Spatial and seasonal abundance of sand seatrout (Cynoscion arenarius) and silver seatrout (C. nothus) off the coast of Texas, determined with twenty years of data (1987–200

Sand seatrout (Cynoscion arenarius) and silver seatrout (C. nothus) are both found within the immediate offshore areas of the Gulf of Mexico, especially around Texas; however information is limited on how much distributional overlap really occurs between these species. In order to investigate spatial and seasonal differences between species, we analyzed twenty years of bay and offshore trawl data collected by biologists of the Coastal Fisheries Division, Texas Parks and Wildlife Department. Sand seatrout and silver seatrout were distributed differently among offshore sampling areas, and salinity and water depth appeared to correlate with their distribution. Additionally, within the northernmost sampling area of the gulf waters, water depth correlated significantly with the presence of silver seatrout, which were found at deeper depths than sand seatrout. There was also an overall significant decrease in silver seatrout abundance during the summer season, when temperatures were at their highest, and this decrease may have indicated a migration farther offshore. Sand seatrout abundance had an inverse relationship with salinity and water depth offshore. In addition, sand seatrout abundance was highest in bays with direct passes to the gulf and correlated with corresponding abundance in offshore areas. These data highlight the seasonal and spatial differences in abundance between sand and silver seatrout and relate these differences to the hydrological and geological features found along the Texas coastline