Chromosome Evolution in Cyperales

Karyotypic evolution is a prominent feature in the diversification of many plants and animals, yet the role that chromosomal changes play in the process of diversification is still debated. At the diploid level, chromosome fission and/or fusion are necessary components of chromosomal structural change associated with diversification. Yet the genomic features required for these events remain unknown. Here we present an overview of what is known about genomic structure in Cyperales, with particular focus on the current level of understanding of chromosome number and genome size and their impact in a phylogenetic context. We outline ongoing projects exploring genomic structure in the order using modern genomics techniques coupled with traditional data sets. Additionally, we explore the questions to which this approach might be best applied, and in particular, detail a project exploring the nature of genomic structural change at the diploid level in genus Carex, a group in which chromosome fission/fusion events are common and associated with diversification of many of its 2000 species. A hypothesized mechanism for chromosome number change in this genus is agmatoploidy, denoting changes in chromosome number without change in DNA amount through fission/fusion of holocentric chromosomes (chromosomes without localized centromeres). This project includes the creation of bacterial artificial chromosome (BAC) and expressed sequence tagged (EST) libraries to be used in physical and genetic linkage mapping studies in order to reveal the patterns of genome structural variation associated with agmatoploidy in Carex, and to explore the sequence and genic characteristics of chromosomal break points in the genome

Apatite-Melt Partitioning at 1 Bar: An Assessment of Apatite-Melt Exchange Equilibria Resulting from Non-Ideal Mixing of F and Cl in Apatite

The mineral apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials. Due to the presence of volatiles within its crystal structure (X-site), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources. In order to use the volatile contents of apatite to precisely determine the abundances of volatiles in coexisting silicate melt or fluids, thermodynamic models for the apatite solid solution and for the apatite components in multi-component silicate melts and fluids are required. Although some thermodynamic models for apatite have been developed, they are incomplete. Furthermore, no mixing model is available for all of the apatite components in silicate melts or fluids, especially for F and Cl components. Several experimental studies have investigated the apatite-melt and apatite-fluid partitioning behavior of F, Cl, and OH in terrestrial and planetary systems, which have determined that apatite-melt partitioning of volatiles are best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, McCubbin et al. recently reported that the exchange coefficients may vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite. In particular, solution calorimetry data of apatite compositions along the F-Cl join exhibit substantial excess enthalpies of mixing. In the present study, we conducted apatite-melt partitioning experiments in evacuated, sealed silica-glass tubes at approximately 1 bar and 950-1050 degrees Centigrade on a synthetic Martian basalt composition equivalent to the basaltic shergottite Queen Alexandria Range (QUE) 94201. These experiments were conducted dry, at low pressure, to assess the effects of temperature and apatite composition on the partitioning behavior of F and Cl between apatite and basaltic melt along the F-Cl apatite binary join, where there is non-ideal mixing of F and Cl in apatite

Fast ultrasonic phased array inspection of complex geometries delivered through robotic manipulators and high speed data acquisition instrumentation

Performance of modern robotic manipulators has enabled research and development of fast automated non-destructive testing (NDT) systems for complex geometries. This paper presents recent outcomes of work aimed at removing the bottleneck due to data acquisition rates, to fully exploit the scanning speed of modern 6-DoF manipulators. State of the art ultrasonic instrumentation has been integrated into a large robot cell to enable fast data acquisition, high scan resolutions and accurate positional encoding. A fibre optic connection between the ultrasonic instrument and the server computer enables data transfer rates up to 1.6GB/s. Multiple data collection methods are compared. Performance of the integrated system allows traditional ultrasonic phased array scanning as well as full matrix capture (FMC). In FMC configuration, linear scan speeds up to 156mm/s with 64 pulses per frame are achieved - this speed is only constrained by the acoustic wave propagation in the component. An 8x increase of the speed (up to 1.25m/s) can be achieved using multiple transmission elements, reaching the physical limits for acceptable acoustic alignment of transmission and reception paths. Scan results, relative to a 1.2m × 3m carbon fibre sample, are presented

Systolic blood pressure and effects on threat appraisal and risk behavior

Appropriate coping methods must be utilized to deal with stressors. While hypertension may reduce an individual\u27s appropriate emotional recognition, we believe that this may have a blanket affect on other areas of appraisal including risk behavior. In the current study resting systolic blood pressure was recorded using a calibrated GE Dinamap Pro 100v2. A modified Youth Risk Behavior Survey in 88 young adults assessed risk behavior score. Men had marginally higher risk scores (.461 +/- .0255) than women (.400 +/- .01836; p=.059). Risk behavior was positively correlated with systolic blood pressure (r(88)=.358, p\u3c.001). Risk taking behaviors approached significance in males (r(88)=-.203, p\u3c.058). The results indicate young adults who may be at risk for hypertension later in life partake in more risk taking behavior suggesting that cardiovascular dysfunction can reduce threat appraisal not allowing the individual to realize the extent of danger certain actions or situations can cause

Artemis Curation: Preparing for Sample Return from the Lunar South Pole

Space Policy Directive-1 mandates that the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations. In addition, the Vice President stated that It is the stated policy of this administration and the United States of America to return American astronauts to the Moon within the next five years, that is, by 2024. These efforts, under the umbrella of the recently formed Artemis Program, include such historic goals as the flight of the first woman to the Moon and the exploration of the lunar south-polar region. Among the top priorities of the Artemis Program is the return of a suite of geologic samples, providing new and significant opportunities for progressing lunar science and human exploration. In particular, successful sample return is necessary for understanding the history of volatiles in the Solar System and the evolution of the Earth-Moon system, fully constraining the hazards of the lunar polar environment for astronauts, and providing the necessary data for constraining the abundance and distribution of resources for in-situ resource utilization (ISRU). Here we summarize the ef-forts of the Astromaterials Acquisition and Curation Office (hereafter referred to as the Curation Office) to ensure the success of Artemis sample return (per NASA Policy Directive (NPD) 7100.10E)

Correction of B-scan distortion for optimum ultrasonic imaging of back walls with complex geometries

Ultrasound undergoes refraction and reflection at interfaces between media of different acoustic refractive indices. The most common ultrasonic method (pulse-echo) monitors the reflected energy to infer the presence of flaws, whereas the lower amplitude of refracted signals is ignored. When the reflector is orientated normally with respect to the ultrasonic beam, the received echo signal shows the maximum amplitude. The pulse-echo method also relies on monitoring the amplitude of the backwall echo to identify or confirm the presence of defects. This works well for parts with constant thickness and with planar backwalls. Unfortunately, parts with complex backwalls are common to many industrial sectors. For example, applications such as aerospace structures often require parts with complex shapes. Assessing such parts reliably is not trivial and can cause severe downtime in the aerospace manufacturing processes or during in-service inspections. This work aims to improve the ultrasonic inspectability of parts with complex backwalls, through sending ultrasonic beams from the frontwall side. Ultrasonic phased array probes and state-of-the-art instrumentation allow ultrasonic energy to be sent into a part at wide ranges of focusing depths and steering angles. This allows for tracking of the backwall profile, thus hitting it normally and maximising the amplitude of the reflected echo at any point. However, this work has shown that a cross-sectional scan resulting from multiple ultrasonic beams, which are sent at variable incidence angles, can present significant geometrical distortion and cannot be of much use for accurate defect visualisation and sizing. This paper introduces a generalised algorithm developed to remove geometric distortions and the effect that variable refraction coefficients have on the transmitted and received amplitudes. The algorithm was validated through CIVA simulations for two example parts with complex backwalls, considering isotropic materials

Stability of Actinolite on Venus

Venus currently has a hostile surface environment with temperatures of ~460 C, pres-sures near 92 bars, and an atmosphere composed of super critical CO2 hosting a myriad of other potentially reactive gases (e.g., SO2, HCl, HF). However, it has been proposed that its surface may not have always been so harsh. Models suggest there may have been billions of years of clement conditions allowing an Earth-like environment with liquid water oceans. If such conditions existed, it is possible Venus formed a similar array of hydrous or aqueous minerals as seen on other planets with liquid surface water (e.g., Mars, Earth). Based on thermodynamic modeling, many of these phases would not be stable under the current atmospheric conditions on Venus, dehydrating due to the high temperatures and low concentration of H2O in the atmosphere. However, the rate of decomposition of these phases may allow them to remain present on the surface over geologic time. For example, experiments on the reaction rate of tremolite (Ca2Mg5Si8O22(OH)2) show a 50% decomposition time of 2.7 Gyr for micrometer sized grains in unreactive atmospheres (i.e., without SO2) at 740 K, and a 50% decomposition time of 70 Gyr for crystals several millimeters to centimeters in size. If hydrous minerals can remain on the surface of Venus over geologic time, it has implications for our detection of evidence of these past environments, and also for the overall water budget of the planet. If after surficial dehydration the planet was able to still store water in its crust, possible processes such as subduction or metamorphism could still have operated using stored water long after liquid surface water evaporated. Several previous studies have focused on experimental investigations of mineral stability on Venus. In particular, the works of studied the decomposition rate of tremolite under conditions relevant to Venus. As their focus was on decomposition of the mineral due to lack of water in the atmosphere, their experiments were undertaken using only CO2 or N2 gas at atmospheric pressure. Re-cent experiments have examined reactivity of other minerals with the Venusian atmosphere using more complex gas compositions at similar pressures to those seen on Venus. These studies show reaction of silicate minerals with atmospheric components on relatively short timescales (i.e., on the order of days). The reported reactions of silicate materials in both studies produced iron oxides, Ca sulfates, and Na sulfates. These ions are present in many amphiboles, and Ca was proposed by Johnson and Fegley to potentially have an important role in the decomposition mechanism for tremolite, with the Ca-O bond being the first to break during decomposition. The potential involvement of Ca in both processes raises the question of whether or not the reaction to form a secondary mineral phase will influence the rate of amphibole break-down (e.g., discussion in for tremolite). Additionally, reaction of Ca with atmospheric gases may result in a different secondary mineral assemblage than simple amphibole decomposition, which will need to be recognized when searching for evidence of past hydrated minerals on the Venusian surface. In order to understand the effect of this reaction on the overall preservation potential of amphibole on the surface of Venus, we are conducting experiments in both reactive and nonreactive atmospheres using the mineral actinolite (Ca2(Mg,Fe)5Si8O22(OH)2), an amphibole with similar crystal structure to tremolite that contains both Ca and Fe

Robotic geometric and volumetric inspection of high value and large scale aircraft wings

Increased demands in performance and production rates require a radical new approach to the design and manufacturing of aircraft wings. Performance of modern robotic manipulators has enabled research and development of fast automated non-destructive testing (NDT) systems for complex geometries. This paper presents recent outcomes of work aimed at removing the bottleneck due to data acquisition rates, to fully exploit the scanning speed of modern 6-DoF manipulators. The geometric assessment of the parts is carried out with a robotised dynamic laser scanner encoded through an absolute laser tracker. This method allows scanning speeds up to 330mm/s at 1mm pitch. State of the art ultrasonic instrumentation has been integrated into a large robot cell to enable fast data acquisition, high scan resolutions and accurate positional encoding. A fibre optic connection between the ultrasonic instrument and the server computer enables data transfer rates up to 1.6 GB/s. The robotic inspection system presented herein is currently being tested for industrial exploitation. The adopted system integration strategies allow traditional ultrasonic phased array scanning as well as full matrix capture (FMC) and other novel scanning approaches (e.g. multi-Tx phased array). Scan results, relative to a 1.2m x 3m carbon fibre sample, are presented. The system shows a reference scanning rate of 25.3m2/hour with an 8Tx/8Rx PA approach and an ultrasonically reachable scanning rate over 100m2/hour with the novel techniques