Microbial D/H fractionation in extraterrestrial materials: application to micrometeorites and Mars

High D/H terrestrial alteration of micrometeorites is described and suggested to be a result of microbial isotopic fractionation by methanogens. Applications to other planetary materials, including martian meteorites, are also considered

Cryptoendolith alteration of Antarctic sandstone substrates: pioneers or opportunists?

The cryptoendolithic habitat of the Antarctic Dry Valleys has been considered a good analogy for past Martian ecosystems, if life arose on the planet. Yet cryptoendoliths are thought to favor the colonization of rocks that have a preexisting porous structure, e. g., sandstones. This may weaken their significance as exact analogues of potential rock-colonizing organisms on Mars, given our current understanding of the dominant volcanic nature of Martian geology. However, the production of oxalic acid, by these lichendominated communities, and its weathering potential indicate that it could be an aid in rock colonization, enabling endoliths to inhabit a wider variety of rock types. Utilizing ICP-AES and scanning electron microscope techniques, this study investigates elemental and mineralogical compositions within colonized and uncolonized layers in individual sandstone samples. This is in order to determine if the weathering of mineral phases within the colonized layers causes an increase in the amount of pore space available for colonization. The results show that colonized layers are more weathered than uncolonized, deeper portions of the rock substrate. Layers within uncolonized samples have uniform compositions. Differences between the colonized and uncolonized layers also occur to varying extents within colonized rocks of different mineralogical maturities. The results confirm that cryptoendoliths modify their habitat through the production of oxalic acid and suggest that over time this directly increases the porosity of their inhabited layer, potentially increasing the biomass it can support

Cryptoendolith colonization of diverse substrates (1): cultivation and characterization

We are investigating whether cryptoendolithic microorganisms are able to colonize diverse substrates through biogenic weathering. This first part of the study involves the cultivation and characterization of microbial consortia from Antarctic sandstone habitats

Development of techniques and technology for full polarimetric radar applied to concealed weapons detection

One of the biggest threats to modern society is the increasing use by criminals and terrorists of concealed weapons and person born improvised explosive devices (PBIED). Current highly mature security screening technologies using x-ray and metal detectors have limited deployment scenarios based on health and safety issues and operational range, respectively. Given that most clothing is greater than 90% transmissive in the microwave region, this spectral band is ideal for screening people for concealed threats. However, due to diffraction, imagery to screen subjects is limited due to the small number of pixels. In this regime, the exploitation of microwave polarimetry from the field of remote sensing has particular benefits, as it extracts maximum information content from a single pixel. The work presented in this thesis has assembled a full polarimetric frequency stepped radar from a vector network analyser (VNA), a linear orthogonal mode transducer (OMT) of the turnstile type and a conical corrugated horn antenna. The system’s characterisation by antenna pattern measurements, the measuring of canonical targets of the plane, dihedral, dipole and helical reflectors showed the system to be capable of making localised Sinclair matrix measurements of targets at ranges of two to three metres. The work presents a calibration procedure comprising the VNA’s internal calibration and an external calibration to compensate for dispersion and cross-polar leakage of system components. Static target measurements (canonical and various surrogate items) were analysed, using range gating for clutter rejection. Calibrated Sinclair parameter measurements compared with those from simple simulations, all software being programmed in Matlab. Measurements of moving targets revealed the phenomenon of speckle, this introducing rapid changes in the Sinclair Parameters. Data analysis performed using the coherency matrix and the Cloude/Pottier decomposition minimised the effects of speckle in the processed data. Measurements show movement from particularly rough surfaces increased the parameter of the Cloude/Pottier entropy, the level of this being directly linked to the degree of speckle. Application of the Huynen polarisation fork technique (a type of decomposition) has proved to aid the identification of static and moving targets. A detailed analysis of iii the Huynen fork responses is made of the human torso on its own, weapons on their own and then weapons positioned against the human torso. Responses of nondangerous objects such as keys and a smartphone are additionally presented

Introduction to the Process of the Institutional Review Board (IRB) for Research with Human Subjects

During the past SO years, law-makers and researchers in the United States have sought legal and procedural methods to reduce risks and harms to research subjects. An important process has been the creation of IRBs at institutions of higher education. The purpose of laws and rules about research review are to: Safeguard the rights and welfare of human subjects in research and related activities. Assist faculty to avoid the possibility of unknowingly committing unethical acts. This article describes three principles of conducting research with human subjects, steps in applying for IRB approval, three levels of research that require !RB review, characteristics of an informed consent form, and some cases for discussion and application of the principles

Association between ethnicity and obesity with high-density lipoprotein (HDL) function and subclass distribution

Abstract Background Obesity and low high-density lipoprotein-cholesterol (HDL-C) levels are associated with cardiovascular risk. Surprisingly, despite a greater prevalence of obesity and lower HDL concentrations than white women, black South African women are relatively protected against ischaemic heart disease. Methods We investigated whether this apparent discrepancy may be related to different HDL function and subclass distribution in black and white, normal-weight and obese South African women (n = 40). HDL functionality was assessed by measuring paraoxonase (PON) activity, platelet activating factor acetylhydrolase (PAF-AH) activity, Oxygen Radical Absorbance Capacity (ORAC) and quantification of the expression of vascular cell adhesion molecule in endothelial cells. PON-1 and PAF-AH expression was determined in isolated HDL and serum using Western blotting. Levels of large, intermediate and small HDL subclasses were measured using the Lipoprint® system. Results PON activity was lower in white compared to black women (0.49 ± 0.09 U/L vs 0.78 ± 0.10 U/L, p < 0.05), regardless of PON-1 protein levels. Obese black women had lower PAF-AH activity (9.34 ± 1.15 U/L vs 13.89 ± 1.21 U/L, p <0.05) and HDL-associated PAF-AH expression compared to obese white women. Compared to normal-weight women, obese women had lower large HDL, greater intermediate and small HDL; an effect that was more pronounced in white women than black women. There were no differences in antioxidant capacity or anti-inflammatory function across groups. Conclusions Our data show that both obesity and ethnicity are associated with differences in HDL functionality, while obesity was associated with decreases in large HDL subclass distribution. Measuring HDL functionality and subclass may, therefore, be important factors to consider when assessing cardiovascular risk

Human Systems Integration in the Federal Government

Human Systems Integration principles and methods can be used to help integrate people, technology, and organizations in an effective and efficient manner. Over the past decade, a wide range of tools, techniques, and technologies have been developed by federal agencies to achieve significant cost and performance benefits. In this discussion, we will explore trends in military human systems integration and learn about the critical role being played by human performance and effectiveness research. We will also examine case studies on the planning and design of future human space flight vehicles, the national air space system and the first nuclear reactors to be built in the United States in over 30 years. And with an eye toward sustaining the discipline s principles and methods, we ll take a look at educating and training the next generation of human systems integration practitioners

Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is still falling as the ambient temperature is reduced to 20 K. Stability tests of the FEMs, including a measurement of the 1/f knee frequency, also meet mission requirements. The 30 and 44 GHz FEMs have met or bettered the mission requirements in all critical aspects. The most sensitive LNAs have reached new limits of noise temperature for HEMTs at their band centres. The FEMs have well-defined linear polarization characteristcs.Comment: 39 pages, 33 figures (33 EPS files), 12 tables. Planck LFI technical papers published by JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/1748-022

Planck pre-launch status: calibration of the Low Frequency Instrument flight model radiometers

The Low Frequency Instrument (LFI) on-board the ESA Planck satellite carries eleven radiometer subsystems, called Radiometer Chain Assemblies (RCAs), each composed of a pair of pseudo-correlation receivers. We describe the on-ground calibration campaign performed to qualify the flight model RCAs and to measure their pre-launch performances. Each RCA was calibrated in a dedicated flight-like cryogenic environment with the radiometer front-end cooled to 20K and the back-end at 300K, and with an external input load cooled to 4K. A matched load simulating a blackbody at different temperatures was placed in front of the sky horn to derive basic radiometer properties such as noise temperature, gain, and noise performance, e.g. 1/f noise. The spectral response of each detector was measured as was their susceptibility to thermal variation. All eleven LFI RCAs were calibrated. Instrumental parameters measured in these tests, such as noise temperature, bandwidth, radiometer isolation, and linearity, provide essential inputs to the Planck-LFI data analysis.Comment: 15 pages, 18 figures. Accepted for publication in Astronomy and Astrophysic