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Study Design Cross-sectional study.Objectives To describe experienced sitting-related health and stability problems among persons with paraplegia (PP) or tetraplegia (TP) and to investigate associations with personal, lesion and wheelchair characteristics as well as satisfaction with sitting posture.Setting Dutch community.Methods A self-report questionnaire on seating was developed and completed by wheelchair-users living with Spinal Cord Injury (SCI) for >= 10 years (N= 264). Sitting-related problems and satisfaction with sitting posture were compared between participants with PP and TP using Chi-square and t-tests. Logistic regression analyses were performed to investigate associated characteristics.Results Reported sitting-related problems comprised: sitting to be tiring (regularly to always) (33%), sitting to be painful (28%), pressure ulcers in the last three months (29%), instability while sitting (8%) and instability during reaching (33%). Except for instability during reaching, no differences in occurrence of sitting-problems were found between lesion-group. Persons with TP were more dissatisfied with their sitting posture than persons with PP: 51% vs 36% (p = 0.022) and 51% and 47% respectively thought their sitting posture could be improved (p = 0 .670) . 'Experienced lack of support in the wheelchair' was associated with most sitting-problems. Pain and instability were associated with dissatisfaction with sitting posture.Conclusion Sitting-related problems and dissatisfaction with sitting posture were frequently reported by persons with long-standing SCI. Sitting problems appeared to associate with lacking support in the wheelchair/seating. A comprehensive feedback from the wheelchair user and a stability check (reach task), as part of the wheelchair/seating-user fitting, may contribute to prevention of sitting-related problems.

We report the first direct measurement of the Ne/O abundance ratio of the interstellar neutral gas flowing into the inner heliosphere. From the first year of Interstellar Boundary Explorer IBEX data collected in spring 2009 we derive the fluxes of interstellar neutral oxygen and neon. Using the flux ratio at the location of IBEX at 1 AU at the time of the observations and using the ionization rates of neon and oxygen prevailing in the heliosphere during the period of solar minimum we estimate the neon/oxygen ratios at the heliospheric termination shock and in the gas phase of the inflowing local interstellar medium. Our estimate is (Ne/O)(gasISM) = 0.27 +/ 0.10 which is within the large given uncertainties consistent with earlier measurements from pickup ions. Our value is larger than the solar abundance ratio possibly indicating that a significant fraction of oxygen in the local interstellar medium is hidden in grains and/or ices.

Thermal certification campaigns in the temperature ranges of 50 degrees C to +85 degrees C and 70 degrees C to +130 degrees C on charge state conversion surfaces (aluminum oxide coatings on a silicon wafer substrate) were performed. Such surfaces are often used in neutral particle sensing instruments in space science where neutral atoms must be ionized prior to their analysis. Ion scattering and atomic force microscope (AFM) instruments were used to characterize the surface properties e.g. surface roughness angular scattering distribution and negative ionization efficiency of charge state conversion surfaces before and after thermal certification campaigns. No significant changes in surface roughness were found in AFM images whereas ion scattering measurements revealed a significant increase of the angular scattering distribution of up to 21 after thermal campaign in the expanded temperature range of 70 degrees C to +130 degrees C. The present study shows clearly that ion scattering measurements are sensitive enough to measure surface changes on atomic and sub atomic level whereas at this level the AFM instrument finds its limits. (C) 2012 Elsevier B.V. All rights reserved.

We report on the design and experimental verification of a novel charged particle detector and an energy spectrometer with variable geometric factor functionality. Charged particle populations in the inner heliosphere create fluxes that can vary over many orders of magnitude in flux intensity. Space missions that plan to observe plasma fluxes for example when travelling close to the Sun or to a planetary magnetosphere require rapid particle measurements over the full three dimensional velocity distribution. Traditionally such measurements are carried out with plasma instrumentation with a fixed geometrical factor which can only operate in a limited range of flux intensity. Here we report on the design and testing of a prototype sensor which is capable of measuring particle flux with high angular and energy resolution yet has a variable geometric factor that is controlled without moving parts. This prototype was designed in support of a proposal to make fast electron measurements on the Solar Probe Plus (SP+) mission planned by NASA. We simulated the ion optics inside the instrument and optimized the performance to design and build our prototype. This prototype was then tested in the MEFISTO facility at the University of Bern and its performance was verified over the full range of azimuth elevation energy and intensity.

The DYANA campaign in early 1990 gave a unique opportunity to study the gravity wave (GW) activity in the middle atmosphere in relation to the general circulation. Several instruments, including Rayleigh lidars, ME and meteor radars, OH and O2 spectrometers and radio-wave absorption receivers provided data at various locations in Europe and Canada to study the GW activity during the campaign. These sets of data indicate that the GW activity is in general enhanced during periods of strong westerly prevailing winds or high planetary-wave activity in the middle atmosphere. When two sets of data are compared, they show a rather fast decorrelation as a function of altitude difference or horizontal distance. This study confirms that the level of GW activity in the middle atmosphere is very sensitive to filtering by the mean wind, but does not exclude its sensitivity to the sources of GW. © 1994.

Experiments are described dealing with immune sera to pentapeptides and peptide amides. Absorption and inhibition tests gave no indication of the presence in the immune sera of special antibodies for portions of a peptide molecule but the antibodies appeared to be specific for an entire pentapeptide even though the sera contained qualitatively different fractions. Marked disparity was found between the reactions of peptides and corresponding amides indicating differences between acid and other polar groups in their influence on serological specificity.

From the experiments presented, it follows that the specific precipitation and the production of anaphylactic shock with certain azodyes, as described previously, is due to these substances themselves and is not dependent upon formation of azoproteins by interaction of the dyes with proteins in the test tube or the animal body. Besides these, some other azodyes which in our tests did not give precipitation with corresponding immune sera were also found, in very small quantities, to induce anaphylactic contraction of the uterus of sensitized guinea pigs.

International audience; In recent times it has become increasingly clear thatreleases of trace gases from human activity have a potentialfor causing change in the upper atmosphere. However,our knowledge of systematic changes and trends inthe temperature of the mesosphere and lower thermosphereis relatively limited compared to the Earths loweratmosphere, and not much effort has been made to synthesizethese results so far. In this article, a comprehensivereview of long-term trends in the temperature of the regionfrom 50 to 100 km is made on the basis of the availableup-to-date understanding of measurements and model calculations.An objective evaluation of the available datasets is attempted, and important uncertainly factors arediscussed. Some natural variability factors, which arelikely to play a role in modulating temperature trends,are also briefly touched upon. There are a growing numberof experimental results centered on, or consistent with,zero temperature trend in the mesopause region (80–100km). The most reliable data sets show no significant trendbut an uncertainty of at least 2 K/decade. On the otherhand, a majority of studies indicate negative trends inthe lower and middle mesosphere with an amplitude ofa few degrees (2–3 K) per decade. In tropical latitudesthe cooling trend increases in the upper mesosphere.The most recent general circulation models indicateincreased cooling closer to both poles in the middlemesosphere and a decrease in cooling toward the summerpole in the upper mesosphere. Quantitatively, thesimulated cooling trend in the middle mesosphere producedonly by CO2 increase is usually below the observedlevel. However, including other greenhouse gasesand taking into account a “thermal shrinking” of theupper atmosphere result in a cooling of a few degreesper decade. This is close to the lower limit of the observednonzero trends. In the mesopause region, recentmodel simulations produce trends, usually below 1 K/decade,that appear to be consistent with most observationsin this region

The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric particle dynamics at Mercury as well as their interactions with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for ion and neutral particle detection aboard the MPO. It comprises four independent sensors: ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA is managed by a System Control Unit located inside the ELENA box. In the present paper the scientific goals of this suite are described, and then the four units are detailed, as well as their major features and calibration results. Finally, the SERENA operational activities are shown during the orbital path around Mercury, with also some reference to the activities planned during the long cruise phase.