Color/magnitude calibration for National Aeronautics and Space Administration (NASA) standard Fixed-Head Star Trackers (FHST)

This paper characterizes and analyzes the spectral response of Ball Aerospace fixed-head star trackers, (FHST's) currently in use on some three-axis stabilized spacecraft. The FHST output is a function of the frequency and intensity of the incident light and the position of the star image in the field of view. The FHST's on board the Extreme Ultraviolet Explorer (EUVE) have had occasional problems identifying stars with a high B-V value. These problems are characterized by inaccurate intensity counts observed by the tracker. The inaccuracies are due to errors in the observed star magnitude values. These errors are unique to each individual FHST. For this reason, data were also collected and analyzed from the Upper Atmosphere Research Satellite (UARS). As a consequence of this work, the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) hopes to improve the attitude accuracy on these missions and to adopt better star selection procedures for catalogs

In vitro fermentation of different ratios of alfalfa and starch or inulin incubated with an equine faecal inoculum

The aim of this work was to assess the impact of substituting starch (S) or inulin (I) with high-temperature dried alfalfa (HTDA) as substrates for in vitro fermentation with an equine faecal inoculum. A series of experiments were conducted to assess the fermentation kinetics of HTDA (chopped [CA] or ground [GA]) and either S or I mixed in the following ratios; 100:0, 80:20, 60:40, 40:60 and 20:80S/I: CA/GA, respectively. For each experiment, a further set of bottles containing identical ratios of S/I: CA/GA were also prepared, with the exception that the alfalfa received a simulated foregut digestion treatment (SFD) as prior to incubation. Total gas production increased (P<0.05) as the ratio of S/I to alfalfa increased. Total gas production was lower in bottles containing SFD-treated alfalfa (P<0.001). Dry matter loss decreased proportionately with increasing level of alfalfa substitution of S/I (P<0.001). Values for pH were lower in bottles containing S or I, with pH values in bottles containing S alone falling to almost 6 and those with I dropping to pH 5 and under. However, the substitution of S or I with 40% alfalfa produced pH values above 6.7, which is within physiological levels encountered in the large intestine of the horse. Consequently, there appears to be considerable potential to buffer the deleterious effects of high-starch/fructan diets with the substitution of these substrates with high-temperature dried alfalfa

Prediction of extreme events in the OFC model on a small world network

We investigate the predictability of extreme events in a dissipative Olami-Feder-Christensen model on a small world topology. Due to the mechanism of self-organized criticality, it is impossible to predict the magnitude of the next event knowing previous ones, if the system has an infinite size. However, by exploiting the finite size effects, we show that probabilistic predictions of the occurrence of extreme events in the next time step are possible in a finite system. In particular, the finiteness of the system unavoidably leads to repulsive temporal correlations of extreme events. The predictability of those is higher for larger magnitudes and for larger complex network sizes. Finally, we show that our prediction analysis is also robust by remarkably reducing the accessible number of events used to construct the optimal predictor.Comment: 5 pages, 4 figure

Linguistic incompetence: giving an account of researching multilingually

This paper considers the place of linguistic competence and incompetence in the context of researching multilingually. It offers a critique of the concept of competence and explores the performative dimensions of multilingual research and its narration, through the philosophy of Judith Butler, and in particular her study Giving an account of oneself. It explores aspects of risk, justice, narrative limit and a morality of multilingualism in emergent multilingual research frameworks. These theoretical dimensions are explored through consideration of ‘linguistically incompetent’ ethnographic work with refugees and asylum seekers, in contexts of hospitality and in life long learning research in the Gaza Strip, and of early attempts to learn new languages. The paper offers a prospect of a relational approach to researching multilingually and affirms the vulnerability at the heart of linguistic hospitality

Trade Study Analysis for TNS Tokamaks.

A series of parametric trade studies was performed to consistently evaluate the relative.costs and performance parameters of D-T burning tokamaks over a range of plasma sizes and toroidal field (TF) coil technologies. Four different types of TF coil technologies were investigated: water-cooled copper coils, superconducting NbTi and Nb{sub 3}Sn coils, and a "hybrid" coil arrangement consisting of a· normal conducting Cu coil nested within a superconducting NbTi coil. Results of the analysis indicate for TNS operation, for example, that for a given plasma beta at ignition, the Cu TF coil devices are least expensive, followed by the Nb{sub 3}Sn, NbTi, and NbTi/Cu options. Other conclusions and trends resulting from the study are presented and analyzed

What is the initiation step of the Grubbs-Hoveyda olefin metathesis catalyst?

Density function theory calculations reveal that the Grubbs-Hoveyda olefin metathesis pre-catalyst is activated by the formation of a complex in which the incoming alkene substrate and outgoing alkoxy ligand are both clearly associated with the ruthenium centre. The computed energies for reaction are in good agreement with the experimental values, reported here

Evaluating the effects of bilingual traffic signs on driver performance and safety

Variable Message Signs (VMS) can provide immediate and relevant information to road users and bilingual VMS can provide great flexibility in countries where a significant proportion of the population speak an alternative language to the majority. The study reported here evaluates the effect of various bilingual VMS configurations on driver behaviour and safety. The aim of the study was to determine whether or not the visual distraction associated with bilingual VMS signs of different configurations (length, complexity) impacted on driving performance. A driving simulator was used to allow full control over the scenarios, road environment and sign configuration and both longitudinal and lateral driver performance was assessed. Drivers were able to read one and two-line monolingual signs and two-line bilingual signs without disruption to their driving behaviour. However, drivers significantly reduced their speed in order to read four-line monolingual and four-line bilingual signs, accompanied by an increase in headway to the vehicle in front. This implies that drivers are possibly reading the irrelevant text on the bilingual sign and various methods for reducing this effect are discussed

Oakleaf: an S locus-linked mutation of Primula vulgaris that affects leaf and flower development

•In Primula vulgaris outcrossing is promoted through reciprocal herkogamy with insect-mediated cross-pollination between pin and thrum form flowers. Development of heteromorphic flowers is coordinated by genes at the S locus. To underpin construction of a genetic map facilitating isolation of these S locus genes, we have characterised Oakleaf, a novel S locus-linked mutant phenotype. •We combine phenotypic observation of flower and leaf development, with classical genetic analysis and next-generation sequencing to address the molecular basis of Oakleaf. •Oakleaf is a dominant mutation that affects both leaf and flower development; plants produce distinctive lobed leaves, with occasional ectopic meristems on the veins. This phenotype is reminiscent of overexpression of Class I KNOX-homeodomain transcription factors. We describe the structure and expression of all eight P. vulgaris PvKNOX genes in both wild-type and Oakleaf plants, and present comparative transcriptome analysis of leaves and flowers from Oakleaf and wild-type plants. •Oakleaf provides a new phenotypic marker for genetic analysis of the Primula S locus. We show that none of the Class I PvKNOX genes are strongly upregulated in Oakleaf leaves and flowers, and identify cohorts of 507 upregulated and 314 downregulated genes in the Oakleaf mutant

Examination Free-Flow Speed Distribution on Two-Lane Rural Roads

[EN] Free-flow speed variation of passenger vehicles along a road segment is one of the most used factors in road safety studies, as a surrogate measure to evaluate road design consistency. Free-flow speed may be measured when a road segment is already built but must be estimated during the design phase. Several studies have been carried out to calibrate models to estimate free-flow speed, with geometric features as explanatory variables. Currently, most free-flow speed models focus only on mean speed or speed in particular percentiles, such as the 85th or 95th. Moreover, most studies have assumed normality in the free-flow speed distribution without checking this hypothesis. The main objective of this study was to analyze the free-flow speed distribution on two-lane rural road curves and tangents. The research focused on two main issues: determining whether speed data were normally distributed at a specific site and analyzing the behavior of the mean and standard deviation of speed on curves and tangents. The study was based on continuous operating speed profiles, which were obtained from a database of more than 16,000 vehicles/km. A total of 63 horizontal curves and 78 tangents were analyzed. According to the results, the normal distribution is not the best distribution in most cases for describing free-flow speeds. In 46 of the curves and 64 of the tangents, free-flow speed cannot be assumed to be normally distributed. Therefore, some other distributions should be tested in further research.The study presented in this paper is part of the research project CASEFU-Estudio experimental de la funcionalidad y seguridad de las carreteras convencionales, subsidized by the Spanish Ministry of Economy and Competitiveness and the European Social Fund. In addition, the authors thank the Center for Studies and Experimentation of Public Works of the Spanish Ministry of Public Works for subsidizing the field data collection, and the Infrastructure and Transportation Department of the General Directorate of Public Works of the Valencian Government, the Valencian Provincial Council, and the Ministry of the Interior, especially the General Directorate of Traffic of Spain, for their cooperation in gathering the field data.García Jiménez, ME.; Pérez Zuriaga, AM.; Llopis-Castelló, D.; Camacho Torregrosa, FJ.; García García, A. (2016). Examination Free-Flow Speed Distribution on Two-Lane Rural Roads. Transportation Research Record Journal of the Transportation Research Board. 2556:86-97. https://doi.org/10.3141/2556-09S8697255