Field reconnaissance geologic mapping of the Columbia Hills, Mars, based on Mars Exploration Rover Spirit and MRO HiRISE observations

Chemical, mineralogic, and lithologic ground truth was acquired for the first time on Mars in terrain units mapped using orbital Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (MRO HiRISE) image data. Examination of several dozen outcrops shows that Mars is geologically complex at meter length scales, the record of its geologic history is well exposed, stratigraphic units may be identified and correlated across significant areas on the ground, and outcrops and geologic relationships between materials may be analyzed with techniques commonly employed in terrestrial field geology. Despite their burial during the course of Martian geologic time by widespread epiclastic materials, mobile fines, and fall deposits, the selective exhumation of deep and well-preserved geologic units has exposed undisturbed outcrops, stratigraphic sections, and structural information much as they are preserved and exposed on Earth. A rich geologic record awaits skilled future field investigators on Mars. The correlation of ground observations and orbital images enables construction of a corresponding geologic reconnaissance map. Most of the outcrops visited are interpreted to be pyroclastic, impactite, and epiclastic deposits overlying an unexposed substrate, probably related to a modified Gusev crater central peak. Fluids have altered chemistry and mineralogy of these protoliths in degrees that vary substantially within the same map unit. Examination of the rocks exposed above and below the major unconformity between the plains lavas and the Columbia Hills directly confirms the general conclusion from remote sensing in previous studies over past years that the early history of Mars was a time of more intense deposition and modification of the surface. Although the availability of fluids and the chemical and mineral activity declined from this early period, significant later volcanism and fluid convection enabled additional, if localized, chemical activity

Bioresorbable Polylactide Interbody Implants in an Ovine Anterior Cervical Discectomy and Fusion Model: Three-Year Results

Study Design. In vivo study of anterior discectomy and fusion using a bioresorbable 70:30 poly(l-lactide-co-d,l-lactide) interbody implant in an ovine model. Objective. To evaluate the efficacy of the polylactide implant to function as an interbody fusion device, and to assess the tissue reaction to the material during the resorption process. Summary of Background Data. The use of polylactide as a cervical interbody implant has several potential advantages when compared with traditional materials. Having an elastic modulus very similar to bone minimizes the potential for stress shielding, and as the material resorbs additional loading is transferred to the developing fusion mass. Although preclinical and clinical studies have demonstrated the suitability of polylactide implants for lumbar interbody fusion, detailed information on cervical anterior cervical discectomy and fusion (ACDF) with polylactide devices is desirable. Methods. Single level ACDF was performed in 8 skeletally mature ewes. Bioresorbable 70:30 poly (l-lactide-co-d,l-lactide) interbody implants packed with autograft were used with single-level metallic plates. Radiographs were made every 3 months up to 1 year, and yearly thereafter. The animals were killed at 6 months (3 animals), 12 months (3 animals), and 36 months (2 animals). In addition to the serial plain radiographs, the specimens were evaluated by nondestructive biomechanical testing and undecalcified histologic analysis. Results. The bioresorbable polylactide implants were effective in achieving interbody fusion. The 6-month animals appeared fused radiographically and biomechanically, whereas histologic sections demonstrated partial fusion (in 3 of 3 animals). Radiographic fusion was confirmed histologically and biomechanically at 12 months (3 of 3 animals) and 36 months (2 of 2 animals). A mild chronic inflammatory response to the resorbing polylactide implant was observed at both 6 months and 12 months. At 36 months, the operative levels were solidly fused and the implants were completely resorbed. No adverse tissue response was observed in any animal at any time period. Conclusion. Interbody fusion was achieved using bioresorbable polylactide implants, with no evidence of implant collapse, extrusion, or adverse tissue response to the material. The use of polylactide as a cervical interbody device appears both safe and effective based on these ACDF animal model results

Relative age of interior layered deposits in southwest Candor Chasma based on high-resolution structural mapping

High-resolution topography generated from stereo HiRISE (High-Resolution Imaging Science Experiment) imagery reveals the meter-scale structure of interior layered deposits (ILD) in southwest Candor Chasma. This study seeks to determine the age of the local ILD relative to any normal faults that can be attributed to chasma formation. The study area is located near the contact of these ILD and the wall rock and is in an area where chasma-forming normal faults have been proposed. We find that while normal faults are found in the study area, these faults are not sufficiently large nor appropriately located or oriented to accommodate the roughly northeast-southwest extension that is required for normal faults that can be attributed to chasma formation. Additionally, bedding exposed in the local ILD generally dips toward the center of Candor Chasma, consistent with sediment deposition in a preexisting basin. Further, pit craters of Tithonia Catena, presumed to predate or be contemporaneous with the formation of west Candor Chasma, do not cut into the ILD within the study area. These independent lines of evidence support a postchasma age for the ILD exposed within the study area. Chasma-related normal faults may exist within these ILD at depth but are not exposed at the surface. Approximately 2 km of conformable stratigraphy is exposed in the study area, and therefore at least several kilometers of the local ILD were deposited subsequent to any chasma-related normal faulting that may have occurred in this part of Candor Chasma

FOOD HABITS AND MANAGEMENT OF INTRODUCED RED FOX IN SOUTHERN CALIFORNIA

Introduced red fox in urban Orange County, California ate a wide variety of foods. Mammals and birds were consumed at all times of the year and both taxa appeared in approximately half or more of the fecal samples at all times of the year. Human supplied food remains were also common and supplemental feeding occurred at all study sites. Supplemental feeding has the potential to exacerbate problems for management of introduced red fox and several endangered species

Identification of RNase-Resistant RNAs in \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e Extracts: Separation from Chromosomal DNA by Selective Precipitation

High-quality chromosomal DNA is a requirement for many biochemical and molecular biological techniques. To isolate cellular DNA, standard protocols typically lyse cells and separate nucleic acids from other biological molecules using a combination of chemical and physical methods. After a standard chemical-based protocol to isolate chromosomal DNA from Saccharomyces cerevisiae and then treatment with RNase A to degrade RNA, two RNase-resistant bands persisted when analyzed using gel electrophoresis. Interestingly, such resistant bands did not appear in preparations of Escherichia coli bacterial DNA after RNase treatment. Several enzymatic, chemical, and physical methods were employed in an effort to remove the resistant RNAs, including use of multiple RNases and alcohol precipitation, base hydrolysis, and chromatographic methods. These experiments resulted in the development of a new method for isolation of S. cerevisiae chromosomal DNA. This method utilizes selective precipitation of DNA in the presence of a potassium acetate/isopropanol mixture and produces high yields of chromosomal DNA without detectable contaminating RNAs

WHITE‐CROWNED MANAKIN (DIXIPHIA PIPRA) USE OF SPACE IN THE ECUADORIAN AMAZON

Abstract ∙ Animal patterns of space use have fundamental consequences for ecological processes such as animal‐ mediated seed dispersal. This study examines the use of space of an understory frugivore: the White‐crowned Manakin (Dixiphia pipra) during the non‐breeding season at Tiputini Biodiversity Station in Ecuador. We radio‐tracked seven individuals of different sexes and ages. We found that White‐crowned Manakins have relatively small home ranges varying from 1.19 to 5.73 ha. The home ranges of male juveniles (2.25 ± 0.62 SE) were larger than that of the adult males (1.20 ± 0.01 SE), but smaller than those of females (4.27 ± 0.77 SE). Females and second‐year males were found to perform more long distance flights outside their core home range than hatch‐year or adult males. These movement differences suggest that they disperse seeds longer distances and more evenly across their home range. Adult and hatch‐year males appear to perform more short distance seed dispersal events. We argue that these contributions are complementary, and that White‐crowned Manakins are key dispersal agents that have a significantly influence in the structure and composition of understory plant communities in the Amazon rainforest.Resumen ∙ Uso de espacio del Saltarín Coroniblanco (Dixiphia pipra) en la Amazonía Ecuatoriana Los patrones de uso espacial utilizados por animales tienen consecuencias fundamentales en procesos ecológicos, tales como la dispersión de semillas. Este estudio examina el uso espacial de una especie frugívora de sotobosque: el Saltarín Coroniblanco (Dixiphia pipra) durante el ciclo no‐reproductivo en la Estación de Biodiversidad de Tiputini en Ecuador. Seguimos por radio telemetría a siete individuos de diferentes sexos y edades. Encontramos que el Saltarín Coroniblanco tiene un rango de hogar relativamente pequeño, variando entre 1,19 a 5,73 ha. El rango de hogar de los machos juveniles (2,25 ± 0,62 EE) es más grande que el de los machos adultos (1,20 ± 0,01 EE), pero más pequeño que el de las hembras (4,27 ± 0,77 EE). El estudio encontró que las hembras y los machos de segundo año realizaron vuelos más largos fuera del núcleo de su rango de hogar, comparado con machos juveniles del año o machos adultos. Estas diferencias sugieren que podrían dispersar semillas a mayores distancias y de manera más homogénea a lo largo de su rango de hogar. Los machos adultos y los juveniles del año parecen llevar a cabo eventos de dispersión de semillas a distancias más cortas. Nosotros argumentamos que estas contribuciones son complementarias y que los Saltarines Coroniblancos son agentes de dispersión claves, influenciando considerablemente la estructura y la composición de las comunidades de plantas del sotobosque en el bosque tropical lluvioso de la Amazonía Ecuatoriana.

Interface degradation in CAS/Nicalon during elevated temperature aging

A CaO-Al{sub 2}O{sub 3}-SiO{sub 2} (CAS)/Nicalon glass-ceramic matrix composite has been subjected to elevated temperature oxidation heat-treatments between 375 and 1200{degrees}C, for up to 100 hours. Micro- and macro-mechanical properties have been determined by fiber push-down, using a mechanical properties microprobe, and flexure testing, respectively. Aging between 450 and 800{degrees}C results in significant property degradation, with reduced bending modulus and flexure strength, increased fiber sliding stress, and a transition to a purely brittle failure mode. Aging degradation is due to oxidative removal of the carbon interlayer, with the subsequent formation of a silica bond between fiber and matrix. At higher temperatures, carbon is retained due to the formation of a protective silica plug at exposed fiber ends, with the subsequent retention of composite properties. Short duration pre-treatment schedules, at 1000 or 1100{degrees}C, were developed to prevent intermediate temperature property degradation

Impact of Size, Secondary Structure, and Counterions on the Binding of Small Ribonucleic Acids to Layered Double Hydroxide Nanoparticles

Use of ribonucleic acid (RNA) interference to regulate protein expression has become an important research topic and gene therapy tool, and therefore, finding suitable vehicles for delivery of small RNAs into cells is of crucial importance. Layered double metal hydroxides such as hydrotalcite (HT) have shown great promise as nonviral vectors for transport of deoxyribose nucleic acid (DNA), proteins, and drugs into cells, but the adsorption of RNAs to these materials has been little explored. In this study, the binding of small RNAs with different lengths and levels of secondary structure to HT nanoparticles has been analyzed and compared to results obtained with small DNAs in concurrent experiments. Initial experiments established the spectrophotometric properties of HT in aqueous solutions and determined that HT particles could be readily sedimented with near 100% efficiencies. Use of RNA+HT cosedimentation experiments as well as electrophoretic mobility shift assays demonstrated strong adsorption of RNA 25mers to HT, with twofold greater binding of single-stranded RNAs relative to double-stranded molecules. Strong affinities were also observed with ssRNA and dsRNA 54mers and with more complex transfer RNA molecules. Competition binding and RNA displacement experiments indicated that RNA-HT associations were strong and were only modestly affected by the presence of high concentrations of inorganic anions

Project overview and update on WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope

We present an overview of and status report on the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT). WEAVE principally targets optical ground-based follow up of upcoming ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project is now in the final design and early procurement phase, with commissioning at the telescope expected in 2017.Comment: 11 pages, 11 Figures, Summary of a presentation to Astronomical Telescopes and Instrumentation 201