Precambrian Felsic and Mafic Dikes Along the Northwestern Margin of the Wyoming Province: Tectonic Constraints from the Southern Highland Mountains, Madison County, Montana

The Precambrian rocks of the southern Highland Mountains in Montana record the geologic history of the northwestern Wyoming craton. Multiple generations of mafic and felsic dikes cut the Archean gneissic fabric and are useful for constraining the Proterozoic tectonic evolution. This study provides mapping of the Nez Perce Hollow and Twin Bridges SW 7.5’ quadrangles with a focus on dike characterization. Also presented here is U-Pb geochronology on two suites of granitic dikes and geochemical data on two suites of mafic dikes. Trace element data shows that amphibolite dikes in the mapping area intruded during a back-arc setting which is constrained in time between 2450 Ma and 1880 Ma. Analyses done here shows that no significant mobilization of elements occurred due to metamorphism, hydrothermal alteration, or chemical weathering and the geochemical signatures can be inferred to be the same for the protolith rock. Samples of diabase dikes have geochemistry similar to the Ramshorn Creek dikes recognized in the Tobacco Root Mountains nearby. This constrains this generation to the Moyie-Purcell large igneous province event ~1460 Ma. Geochronology of the granitic dikes show there are two separate tectonic events separated by ~100 million years. The youngest granite has a best age of 1791±8.1 Ma which corresponds to the timing of the Big Sky Orogeny. The oldest granite has an age of ~1880 Ma which is interpreted to be a previously unrecognized event prior to the Big Sky Orogeny. This result suggests that a new model is needed for the amalgamation of the Wyoming Province and the Medicine Hat block

Precambrian Felsic and Mafic Dikes Along the Northwestern Margin of the Wyoming Province: Tectonic Constraints from the Southern Highland Mountains, Madison County, Montana

The Precambrian rocks of the southern Highland Mountains in Montana record the geologic history of the northwestern Wyoming craton. Multiple generations of mafic and felsic dikes cut the Archean gneissic fabric and are useful for constraining the Proterozoic tectonic evolution. This study provides mapping of the Nez Perce Hollow and Twin Bridges SW 7.5’ quadrangles with a focus on dike characterization. Also presented here is U-Pb geochronology on two suites of granitic dikes and geochemical data on two suites of mafic dikes. Trace element data shows that amphibolite dikes in the mapping area intruded during a back-arc setting which is constrained in time between 2450 Ma and 1880 Ma. Analyses done here shows that no significant mobilization of elements occurred due to metamorphism, hydrothermal alteration, or chemical weathering and the geochemical signatures can be inferred to be the same for the protolith rock. Samples of diabase dikes have geochemistry similar to the Ramshorn Creek dikes recognized in the Tobacco Root Mountains nearby. This constrains this generation to the Moyie-Purcell large igneous province event ~1460 Ma. Geochronology of the granitic dikes show there are two separate tectonic events separated by ~100 million years. The youngest granite has a best age of 1791±8.1 Ma which corresponds to the timing of the Big Sky Orogeny. The oldest granite has an age of ~1880 Ma which is interpreted to be a previously unrecognized event prior to the Big Sky Orogeny. This result suggests that a new model is needed for the amalgamation of the Wyoming Province and the Medicine Hat block

Why Websites Work: An Examination of Interdisciplinary Agricultural Center Websites

This study examined the online content of interdisciplinary agricultural center webpages. Content modification dates, mission statements, and content were determined through a content analysis. Many of the websites did not mention a modification date for the content, while many websites had outdated content mostly older than six months. More than two-thirds of the websites provided PDFs that visitor could download to learn more about topics, by many of the websites lacked any media element that was being coded. Additionally, many websites did not use multiple forms of media. More than half of the websites were coded as lacking any social media content or plugins, but out of the websites that did include social media content, Facebook was the most prevalent. The commonalities between the center’s mission displayed on the website and the content theme were analyzed and chi-square tests provided the degree of association. A significant association existed and an alignment between communication strategies and missions of the centers was concluded, which is important when organizations communicate about agricultural science as indicated by previous literature. It is recommended that centers communicate via their websites in a timely manner and allow modification times to be seen to viewers to show their information is up-to-date. Website media content should also be diversified and communicators of these centers should explore the unique communication opportunities provided by social media. Future research should explore the target audience of interdisciplinary agricultural centers and should analyze the messages centers are using to communicate with those audiences

A Linear Generator Power Take-Off System for the VIVACE Hydrokinetic Energy Converter

Final Report for Team 4 of ME450, Fall 2008 semester.Water is the largest energy storage medium. Of the solar energy available to Earth, 285 ZJoule/year are absorbed by water, 6 ZJoule/year are theoretically available in wind, and 1.8 ZJoule/year are absorbed by biomass. Worldwide energy consumption was 0.471 ZJ in 2004. Marine energy is clean, renewable, abundant, and available worldwide. It comes in five forms: currents, waves, tides, thermal gradient, and salinity gradient. The Challenge: Wave and current/tidal energy pilot devices are environmentally obtrusive and complex. Simpler devices that emulate natural phenomena and fish kinematics are needed. Energy from currents can be harnessed using turbines, which require an average speed of 5-7 knots to be financially viable. The vast majority of currents, however, flow at speeds of less than 3 knots. VIVACE can harness energy from currents even slower than 2 knots. VIVACE is not a turbine; it is an altogether novel concept. The Technology: Flexible bluff structures (particularly cylinders), from fishnet filaments to 120ft diameter SPAR offshore platforms and anything in between, such as car antennas, flagpoles, marine cables, heat exchanger tubes, experience VIV (Vortex Induced Vibration) in a steady flow. Engineers seek to suppress VIV because it causes large motions leading to fatigue and structural failure. The VIVACE (VIV for Aquatic Clean Energy) Converter is designed to do the opposite: maximize and utilize VIV to harness the hydrokinetic energy of flows. Thus, VIVACE takes this natural, destructive, instability phenomenon and transforms it into means of taping into a vast and virtually untapped energy source. VIV is further enhanced using turbulence stimulation and fish-biomimetics. VIVACE models operate in the UM Marine Renewable Energy Lab. VIVACE is modular and scalable from 1kW-1GW.Professor Michael M. Bernitsas, Vortex Hydro Energy LLChttp://deepblue.lib.umich.edu/bitstream/2027.42/61915/1/ME450 Fall2008 Final Report - Team 04 - VIVACE Hydrokinetic Energy Converter.pd

The ECLSS Advanced Automation Project Evolution and Technology Assessment

Viewgraphs on Environmental Control and Life Support System (ECLSS) advanced automation project evolution and technology assessment are presented. Topics covered include: the ECLSS advanced automation project; automatic fault diagnosis of ECLSS subsystems descriptions; in-line, real-time chemical and microbial fluid analysis; and object-oriented, distributed chemical and microbial modeling of regenerative environmental control systems description

The linewidth-size relationship in the dense ISM of the Central Molecular Zone

The linewidth (sigma) - size (R) relationship has been extensively measured and analysed, in both the local ISM and in nearby normal galaxies. Generally, a power-law describes the relationship well with an index ranging from 0.2-0.6, now referred to as one of "Larson's Relationships." The nature of turbulence and star formation is considered to be intimately related to these relationships, so evaluating the sigma-R correlations in various environments is important for developing a comprehensive understanding of the ISM. We measure the sigma-R relationship in the Central Molecular Zone (CMZ) of the Galactic Centre using spectral line observations of the high density tracers N2H+, HCN, H13CN, and HCO+. We use dendrograms, which map the hierarchical nature of the position-position-velocity (PPV) data, to compute sigma and R of contiguous structures. The dispersions range from ~2-30 km/s in structures spanning sizes 2-40 pc, respectively. By performing Bayesian inference, we show that a power-law with exponent 0.3-1.1 can reasonably describe the sigma-R trend. We demonstrate that the derived sigma-R relationship is independent of the locations in the PPV dataset where sigma and R are measured. The uniformity in the sigma-R relationship suggests turbulence in the CMZ is driven on the large scales beyond >30 pc. We compare the CMZ sigma-R relationship to that measured in the Galactic molecular cloud Perseus. The exponents between the two systems are similar, suggestive of a connection between the turbulent properties within a cloud to its ambient medium. Yet, the velocity dispersion in the CMZ is systematically higher, resulting in a coefficient that is nearly five times larger. The systematic enhancement of turbulent velocities may be due to the combined effects of increased star formation activity, larger densities, and higher pressures relative to the local ISM.Comment: 11 pages, 8 figures, Accepted for publication in MNRA

Structural basis for high-affinity binding of LEDGF PWWP to mononucleosomes

Lens epithelium-derived growth factor (LEDGF/p75) tethers lentiviral preintegration complexes (PICs) to chromatin and is essential for effective HIV-1 replication. LEDGF/p75 interactions with lentiviral integrases are well characterized, but the structural basis for how LEDGF/p75 engages chromatin is unknown. We demonstrate that cellular LEDGF/p75 is tightly bound to mononucleosomes (MNs). Our proteomic experiments indicate that this interaction is direct and not mediated by other cellular factors. We determined the solution structure of LEDGF PWWP and monitored binding to the histone H3 tail containing trimethylated Lys36 (H3K36me3) and DNA by NMR. Results reveal two distinct functional interfaces of LEDGF PWWP: a well-defined hydrophobic cavity, which selectively interacts with the H3K36me3 peptide and adjacent basic surface, which non-specifically binds DNA. LEDGF PWWP exhibits nanomolar binding affinity to purified native MNs, but displays markedly lower affinities for the isolated H3K36me3 peptide and DNA. Furthermore, we show that LEDGF PWWP preferentially and tightly binds to in vitro reconstituted MNs containing a tri-methyl-lysine analogue at position 36 of H3 and not to their unmodified counterparts. We conclude that cooperative binding of the hydrophobic cavity and basic surface to the cognate histone peptide and DNA wrapped in MNs is essential for high-affinity binding to chromatin

Antibody-Directed Evolution Reveals a Mechanism for Enhanced Neutralization at the HIV-1 Fusion Peptide Site

The HIV-1 fusion peptide (FP) represents a promising vaccine target, but global FP sequence diversity among circulating strains has limited anti-FP antibodies to ~60% neutralization breadth. Here we evolve the FP-targeting antibody VRC34.01 in vitro to enhance FP-neutralization using site saturation mutagenesis and yeast display. Successive rounds of directed evolution by iterative selection of antibodies for binding to resistant HIV-1 strains establish a variant, VRC34.01_mm28, as a best-in-class antibody with 10-fold enhanced potency compared to the template antibody and ~80% breadth on a cross-clade 208-strain neutralization panel. Structural analyses demonstrate that the improved paratope expands the FP binding groove to accommodate diverse FP sequences of different lengths while also recognizing the HIV-1 Env backbone. These data reveal critical antibody features for enhanced neutralization breadth and potency against the FP site of vulnerability and accelerate clinical development of broad HIV-1 FP-targeting vaccines and therapeutics

Predictors of smoking lapse in a human laboratory paradigm

During a smoking quit attempt, a single smoking lapse is highly predictive of future relapse. While several risk factors for a smoking lapse have been identified during clinical trials, a laboratory model of lapse was until recently unavailable and, therefore, it is unclear whether these characteristics also convey risk for lapse in a laboratory environment.The primary study goal was to examine whether real-world risk factors of lapse are also predictive of smoking behavior in a laboratory model of smoking lapse.After overnight abstinence, 77 smokers completed the McKee smoking lapse task, in which they were presented with the choice of smoking or delaying in exchange for monetary reinforcement. Primary outcome measures were the latency to initiate smoking behavior and the number of cigarettes smoked during the lapse. Several baseline measures of smoking behavior, mood, and individual traits were examined as predictive factors.Craving to relieve the discomfort of withdrawal, withdrawal severity, and tension level were negatively predictive of latency to smoke. In contrast, average number of cigarettes smoked per day, withdrawal severity, level of nicotine dependence, craving for the positive effects of smoking, and craving to relieve the discomfort of withdrawal were positively predictive of number of cigarettes smoked.The results suggest that real-world risk factors for smoking lapse are also predictive of smoking behavior in a laboratory model of lapse. Future studies using the McKee lapse task should account for between subject differences in the unique factors that independently predict each outcome measure