37,221 research outputs found

    A large scale extinction map of the Galactic Anticenter from 2MASS

    Full text link
    We present a 127deg x 63deg extinction map of the Anticenter of the Galaxy, based on and colour excess maps from 2MASS. This 8001 square degree map with a resolution of 4 arcminutes is provided as online material. The colour excess ratio / is used to determine the power law index of the reddening law (\beta) for individual regions contained in the area (e.g. Orion, Perseus, Taurus, Auriga, Monoceros, Camelopardalis, Cassiopeia). On average we find a dominant value of \beta=1.8+-0.2 for the individual clouds, in agreement with the canonical value for the interstellar medium. We also show that there is an internal scatter of \beta values in these regions, and that in some areas more than one dominant \beta value is present. This indicates large scale variations in the dust properties. The analysis of the A_V values within individual regions shows a change in the slope of the column density distribution with distance. This can either be attributed to a change in the governing physical processes in molecular clouds on spatial scales of about 1pc or an A_V dilution with distance in our map.Comment: 18 pages, 29 Figures, 1 Table, Accepted for publication by MNRAS, A version with higher resolution figures can be found at http://astro.kent.ac.uk/~df

    Attitude determination of the spin-stabilized Project Scanner spacecraft

    Get PDF
    Attitude determination of spin-stabilized spacecraft using star mapping techniqu

    Perceptions of Psychological Coercion and Human Trafficking in the West Midlands of England: Beginning to Know the Unknown

    Get PDF
    Modern slavery is less overt than historical state-sanctioned slavery because psychological abuse is typically used to recruit and then control victims. The recent UK Draft Modern Slavery Bill, and current UK government anti-slavery strategy relies heavily on a shared understanding and public cooperation to tackle this crime. Yet, UK research investigating public understanding of modern slavery is elusive. We report community survey data from 682 residents of the Midlands of England, where modern slavery is known to occur, concerning their understanding of nonphysical coercion and human trafficking (one particular form of modern slavery). Analysis of quantitative data and themed categorization of qualitative data revealed a mismatch between theoretical frameworks and understanding of psychological coercion, and misconceptions concerning the nature of human trafficking. Many respondents did not understand psychological coercion, believed that human trafficking did not affect them, and confused trafficking with immigration. The public are one of the most influential interest groups, but only if well informed and motivated towards positive action. Our findings suggest the need for strategically targeted public knowledge exchange concerning this crime

    Overcoming the false-minima problem in direct methods: Structure determination of the packaging enzyme P4 from bacteriophage φ13

    Get PDF
    The problems encountered during the phasing and structure determination of the packaging enzyme P4 from bacteriophage φ13 using the anomalous signal from selenium in a single-wavelength anomalous dispersion experiment (SAD) are described. The oligomeric state of P4 in the virus is a hexamer (with sixfold rotational symmetry) and it crystallizes in space group C2, with four hexamers in the crystallographic asymmetric unit. Current state-of-the-art ab initio phasing software yielded solutions consisting of 96 atoms arranged as sixfold symmetric clusters of Se atoms. However, although these solutions showed high correlation coefficients indicative that the substructure had been solved, the resulting phases produced uninterpretable electron-density maps. Only after further analysis were correct solutions found (also of 96 atoms), leading to the eventual identification of the positions of 120 Se atoms. Here, it is demonstrated how the difficulties in finding a correct phase solution arise from an intricate false-minima problem. © 2005 International Union of Crystallography - all rights reserved

    Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation. Volume 2, Part 2: Appendixes B, C, D and E

    Get PDF
    The derivation of the equations is presented, the rate control algorithm described, and simulation methodologies summarized. A set of dynamics equations that can be used recursively to calculate forces and torques acting at the joints of an n link manipulator given the manipulator joint rates are derived. The equations are valid for any n link manipulator system with any kind of joints connected in any sequence. The equations of motion for the class of manipulators consisting of n rigid links interconnected by rotary joints are derived. A technique is outlined for reducing the system of equations to eliminate contraint torques. The linearized dynamics equations for an n link manipulator system are derived. The general n link linearized equations are then applied to a two link configuration. The coordinated rate control algorithm used to compute individual joint rates when given end effector rates is described. A short discussion of simulation methodologies is presented

    Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation, volume 2, part 1. Appendix A: Software documentation

    Get PDF
    Documentation of the preliminary software developed as a framework for a generalized integrated robotic system simulation is presented. The program structure is composed of three major functions controlled by a program executive. The three major functions are: system definition, analysis tools, and post processing. The system definition function handles user input of system parameters and definition of the manipulator configuration. The analysis tools function handles the computational requirements of the program. The post processing function allows for more detailed study of the results of analysis tool function executions. Also documented is the manipulator joint model software to be used as the basis of the manipulator simulation which will be part of the analysis tools capability

    Supersonic combustion engine testbed, heat lightning

    Get PDF
    The design of a supersonic combustion engine testbed (SCET) aircraft is presented. The hypersonic waverider will utilize both supersonic combustion ramjet (SCRAMjet) and turbofan-ramjet engines. The waverider concept, system integration, electrical power, weight analysis, cockpit, landing skids, and configuration modeling are addressed in the configuration considerations. The subsonic, supersonic and hypersonic aerodynamics are presented along with the aerodynamic stability and landing analysis of the aircraft. The propulsion design considerations include: engine selection, turbofan ramjet inlets, SCRAMjet inlets and the SCRAMjet diffuser. The cooling requirements and system are covered along with the topics of materials and the hydrogen fuel tanks and insulation system. A cost analysis is presented and the appendices include: information about the subsonic wind tunnel test, shock expansion calculations, and an aerodynamic heat flux program

    pH effect on the physico-chemical, microstructural and sensorial properties of processed cheese manufactured with various starches

    Full text link
    Processed cheeses containing 5% w/w potato, waxy maize or corn starch were manufactured in the pH range 4.5–6 to investigate the effect of pH on the physical and microstructural characteristics of high-starch processed cheese. Increased hydrogen bonding between the starch alcohol groups and hydrophilic protein residues was observed with both increasing and decreasing pH, indicating a higher degree of starch distribution. Optical microscopy showed a continuous starch exclusion network in cheeses manufactured with native starch between pH 4.8–5.3, with discrete starch particles present at increased and decreased pH. This network breakdown reduced product hardness and increased meltability, with the 5% starch cheese manufactured at pH 6 exhibiting higher sensory acceptability compared to the non pH modified sample. The present work demonstrates that increasing cheese pH during manufacture can reduce the negative physical characteristics associated with high-starch processed cheese and may provide industry with a cost effective method to increase the sensory acceptance of such products
    corecore