Instrumentation to measure mars' atmospheric composition, using a soft-landed probe

Instrumentation for analysis of Mars atmosphere after soft landin

Thermal Evolution and Radiative Output of Solar Flares Observed by the EUV Variability Experiment (EVE)

This paper describes the methods used to obtain the thermal evolution and radiative output during solar flares as observed by the Extreme u ltraviolet Variability Experiment (EVE) onboard the Solar Dynamics Ob servatory (SDO). Presented and discussed in detail are how EVE measur ements, due to its temporal cadence, spectral resolution and spectral range, can be used to determine how the thermal plasma radiates at v arious temperatures throughout the impulsive and gradual phase of fla res. EVE can very accurately determine the radiative output of flares due to pre- and in-flight calibrations. Events are presented that sh ow the total radiated output of flares depends more on the flare duration than the typical GOES X-ray peak magnitude classification. With S DO observing every flare throughout its entire duration and over a la rge temperature range, new insights into flare heating and cooling as well as the radiative energy release in EUV wavelengths support exis ting research into understanding the evolution of solar flares

An Analogue-Digital Model of Computation: Turing Machines with Physical Oracles

We introduce an abstract analogue-digital model of computation that couples Turing machines to oracles that are physical processes. Since any oracle has the potential to boost the computational power of a Turing machine, the effect on the power of the Turing machine of adding a physical process raises interesting questions. Do physical processes add significantly to the power of Turing machines; can they break the Turing Barrier? Does the power of the Turing machine vary with different physical processes? Specifically, here, we take a physical oracle to be a physical experiment, controlled by the Turing machine, that measures some physical quantity. There are three protocols of communication between the Turing machine and the oracle that simulate the types of error propagation common to analogue-digital devices, namely: infinite precision, unbounded precision, and fixed precision. These three types of precision introduce three variants of the physical oracle model. On fixing one archetypal experiment, we show how to classify the computational power of the three models by establishing the lower and upper bounds. Using new techniques and ideas about timing, we give a complete classification.info:eu-repo/semantics/publishedVersio

Lowest dimensional example on non-universality of generalized In\"on\"u-Wigner contractions

We prove that there exists just one pair of complex four-dimensional Lie algebras such that a well-defined contraction among them is not equivalent to a generalized IW-contraction (or to a one-parametric subgroup degeneration in conventional algebraic terms). Over the field of real numbers, this pair of algebras is split into two pairs with the same contracted algebra. The example we constructed demonstrates that even in the dimension four generalized IW-contractions are not sufficient for realizing all possible contractions, and this is the lowest dimension in which generalized IW-contractions are not universal. Moreover, this is also the first example of nonexistence of generalized IW-contraction for the case when the contracted algebra is not characteristically nilpotent and, therefore, admits nontrivial diagonal derivations. The lower bound (equal to three) of nonnegative integer parameter exponents which are sufficient to realize all generalized IW-contractions of four-dimensional Lie algebras is also found.Comment: 15 pages, extended versio

When is |C(X x Y)| = |C(X)||C(Y)|?

Sufficient conditions on the Tychonoff spaces X and Y are found that imply that the equation in the title holds. Sufficient conditions on the Tychonoff space X are found that ensure that the equation holds for every Tychonoff space Y . A series of examples (some using rather sophisticated cardinal arithmetic) are given that witness that these results cannot be generalized much

Resonance line-profile calculations based on hydrodynamical models of cataclysmic variable winds

We present synthetic line profiles as predicted by the models of 2-D line- driven disk winds due to Proga, Stone & Drew. We compare the model line profiles with HST observations of the cataclysmic variable IX Vel. The model wind consists of a slow outflow that is bounded on the polar side by a fast stream. We find that these two components of the wind produce distinct spectral features. The fast stream produces profiles which show features consistent with observations. These include the appearance of the P-Cygni shape for a range of inclinations, the location of the maximum depth of the absorption component at velocities less than the terminal velocity, and the transition from absorption to emission with increasing inclination. However the model profiles have too little absorption or emission equivalent width. This quantitative difference between our models and observations is not a surprise because the line-driven wind models predict a mass loss rate that is lower than the rate required by the observations. We note that the model profiles exhibit a double-humped structure near the line center which is not echoed in observations. We identify this structure with a non-negligible redshifted absorption which is formed in the slow component of the wind where the rotational velocity dominates over expansion velocity. We conclude that the next generation of disk wind models, developed for application to CVs, needs to yield stronger wind driving out to larger disk radii than do the present models.Comment: LaTeX, 19 pages, to appear in Ap

Breit interaction correction to the hyperfine constant of an external s-electron in many-electron atom

Correction to the hyperfine constant $A$ of an external s-electron in many-electron atom caused by the Breit interaction is calculated analytically: $\delta A/A =0.68 Z\alpha^2$. Physical mechanism for this correction is polarization of the internal electronic shells (mainly $1s^2$ shell) by the magnetic field of the external electron. This mechanism is similar to the polarization of vacuum considered by Karplus and Klein long time ago. The similarity is the reason why in both cases (Dirac sea polarization and internal atomic shells polarization) the corrections have the same dependence on the nuclear charge and fine structure constant. In conclusion we also discuss $Z\alpha^2$ corrections to the parity violation effects in atoms.Comment: 8 pages, 2 figure

A field study of team working in a new human supervisory control system

This paper presents a case study of an investigation into team behaviour in an energy distribution company. The main aim was to investigate the impact of major changes in the company on system performance, comprising human and technical elements. A socio-technical systems approach was adopted. There were main differences between the teams investigated in the study: the time of year each control room was studied (i.e. summer or winter),the stage of development each team was in (i.e. 10 months), and the team structure (i.e. hierarchical or heterarchical). In all other respects the control rooms were the same: employing the same technology and within the same organization. The main findings were: the teams studied in the winter months were engaged in more `planning’ and `awareness’ type of activities than those studies in the summer months. Newer teams seem to be engaged in more sharing of information than older teams, which maybe indicative of the development process. One of the hierarchical teams was engaged in more `system-driven’ activities than the heterarchical team studied at the same time of year. Finally, in general, the heterarchical team perceived a greater degree of team working culture than its hierarchical counterparts. This applied research project confirms findings from laboratory research and emphasizes the importance of involving ergonomics in the design of team working in human supervisory control

The Climatic Water Balance and Topography Control Spatial Patterns of Atmospheric Demand, Soil Moisture, and Shallow Subsurface Flow

Catchment hydrometeorology and the organization of shallow subsurface flow are key drivers of active contributing areas and streamflow generation. However, understanding how the climatic water balance and complex topography contribute to these processes from hillslope to catchment scales remains difficult. We compared time series of vapor pressure deficits and soil moisture to the climatic water balance and topographic variables across six zero-order catchments in the Lubrecht Experimental Forest (Montana, USA). We then evaluated how local hydrometeorology (volumetric water content and atmospheric vapor pressure deficit) affected the spatial occurrence of shallow subsurface flow. Generalized linear mixed model analysis revealed significant, temporally stable (monthly and seasonal average) patterns of hydrometeorology that can be predicted by the topographic wetness index and the dynamic climatic water deficit (CWD = potential evapotranspiration - actual evapotranspiration). Intracatchment patterns were significantly correlated to the topographic wetness index, while intercatchment patterns were correlated to spatiotemporal variance in the CWD during each time period. Spatial patterns of shallow subsurface flow were related to the hydrometeorological conditions of the site. We observed persistent shallow subsurface flow in convergent hillslope positions, except when a catchment was positioned in locations with high CWDs (low elevations and southerly aspects). Alternatively, we observed persistent subsurface flow across all hillslope positions (even 70-m upslope from the hollow) when catchments were positioned in locations with especially low CWDs (northerly aspects and high elevations). These results highlight the importance of considering the superposition of the catchment-scale climatic water balance and hillslope-scale topography when characterizing hydrometeorology and shallow subsurface flow dynamics.USDA NIFA McIntire Stennis award [233327]; NSF grants [DEB-1457749, DEB-1457720]; NASA applied science program Wildland Fire award [NNH11ZDA001N-FIRES]; NSF EPSCoR through the Montana Institute on Ecosystems6 month embargo; published online: 19 February 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Static stretching of the hamstring muscle for injury prevention in football codes: a systematic review

Purpose: Hamstring injuries are common among football players. There is still disagreement regarding prevention. The aim of this review is to determine whether static stretching reduces hamstring injuries in football codes. Methods: A systematic literature search was conducted on the online databases PubMed, PEDro, Cochrane, Web of Science, Bisp and Clinical Trial register. Study results were presented descriptively and the quality of the studies assessed were based on Cochrane’s ‘risk of bias’ tool. Results: The review identified 35 studies, including four analysis studies. These studies show deficiencies in the quality of study designs. Conclusion: The study protocols are varied in terms of the length of intervention and follow-up. No RCT studies are available, however, RCT studies should be conducted in the near future