Flight data analysis of the HyShot 2 scramjet flight experiment

The development of scramjet propulsion for alternative launch and payload delivery capabilities has been composed largely of ground experiments for the last 40 years. With the goal of validating the use of short duration ground test facilities, a ballistic reentry vehicle experiment called HyShot was devised to achieve supersonic combustion in flight above Mach 7.5. It consisted of a double wedge intake and two back-to-back constant area combustors; one supplied with hydrogen fuel at an equivalence ratio of 0.34 and the other unfueled. Of the two flights conducted, HyShot 1 failed to reach the desired altitude due to booster failure, whereas HyShot 2 successfully accomplished both the desired trajectory and satisfactory scramjet operation. Postflight data analysis of HyShot 2 confirmed the presence of supersonic combustion during the approximately 3 s test window at altitudes between 35 and 29 km. Reasonable correlation between flight and some preflight shock tunnel tests was observed.

Quantum entanglement in the two-impurity Kondo model

In order to quantify quantum entanglement in two-impurity Kondo systems, we calculate the concurrence, negativity, and von Neumann entropy. The entanglement of the two Kondo impurities is shown to be determined by two competing many-body effects, namely the Kondo effect and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, I. Due to the spin-rotational invariance of the ground state, the concurrence and negativity are uniquely determined by the spin-spin correlation between the impurities. It is found that there exists a critical minimum value of the antiferromagnetic correlation between the impurity spins which is necessary for entanglement of the two impurity spins. The critical value is discussed in relation with the unstable fixed point in the two-impurity Kondo problem. Specifically, at the fixed point there is no entanglement between the impurity spins. Entanglement will only be created [and quantum information processing (QIP) will only be possible] if the RKKY interaction exchange energy, I, is at least several times larger than the Kondo temperature, T-K. Quantitative criteria for QIP are given in terms of the impurity spin-spin correlation.

Structural and functional characterization of the conserved salt bridge in mammalian Paneth cell alpha-defensins - Solution structures of mouse cryptdin-4 AND (E15D)-cryptdin-4

Defensins are mediators of mammalian innate immunity, and knowledge of their structure-function relationships is essential for understanding their mechanisms of action. We report here the NMR solution structures of the mouse Paneth cell α-defensin cryptdin-4 (Crp4) and a mutant (E15D)-Crp4 peptide, in which a conserved Glu15 residue was replaced by Asp. Structural analysis of the two peptides confirms the involvement of this Glu in a conserved salt bridge that is removed in the mutant because of the shortened side chain. Despite disruption of this structural feature, the peptide variant retains a well defined native fold because of a rearrangement of side chains, which result in compensating favorable interactions. Furthermore, salt bridge-deficient Crp4 mutants were tested for bactericidal effects and resistance to proteolytic degradation, and all of the variants had similar bactericidal activities and stability to proteolysis. These findings support the conclusion that the function of the conserved salt bridge in Crp4 is not linked to bactericidal activity or proteolytic stability of the mature peptide.

Electrophysiological evidence for linear polarization sensitivity in the compound eyes of the stomatopod crustacean Gonodactylus chiragra

Gonodactyloid stomatopod crustaceans possess polarization vision, which enables them to discriminate light of different e-vector angle. Their unusual apposition compound eyes are divided by an equatorial band of six rows of enlarged, structurally modified ommatidia, the mid-band (MB). The rhabdoms of the two most ventral MB rows 5 and 6 are structurally designed for polarization vision. Here we show, with electrophysiological recordings, that the photoreceptors R1-R7 within these two MB rows in Gonodactylus chiragra are highly sensitive to linear polarized light of two orthogonal directions (PS=6.1). They possess a narrow spectral sensitivity peaking at 565 nm. Unexpectedly, photoreceptors within the distal rhabdomal tier of MB row 2 also possess highly sensitive linear polarization receptors, which are in their spectral and polarization characteristics similar to the receptors of MB rows 5 and 6. Photoreceptors R1-R7 within the remainder of the MB exhibit low polarization sensitivity (PS=2.3). Outside the MB, in the two hemispheres, R1-R7 possess medium linear polarization sensitivity (PS=3.8) and a broad spectral sensitivity peaking at around 500 nm, typical for most crustaceans. Throughout the retina the most distally situated UV-sensitive R8 cells are not sensitive to linear polarized light.

A bibliographic snapshot of the telemedicine citation literature

There appear to have been no previous literature-based or literature-oriented studies in telemedicine which have analysed raw citation data. Using a simple search strategy, the Web of Science was analysed up to the end of 2005 to give a snapshot of the field, and to identify matters which would need to be considered in larger scale bibliometric studies. Of the 3673 telemedicine documents retrieved, 2213 (60%) had been cited. Of 56,875 citation records, 32,460 unique citation formats were found. The most-cited paper, and the paper with the greatest annual citation rate, was Perednia and Allen's review article in JAMA, 1995. The two specialist telemedicine journals published 40% of all papers retrieved. In the general literature (i.e. excluding the two specialist journals) there were 1556 citations to their 1374 'citable' articles, apportioned in the ratio 76:24, almost exactly in accordance with the distribution of the articles themselves. However, each of the two specialist telemedicine journals cited itself in a proportion higher than its share of original articles, with an 'excess' of self-citations of 14% in the journal of Telemedicine and Telecare, and 19% in the Telemedicine journal and E-Health. Despite certain technical difficulties, there is considerable scope for bibliometric research in telemedicine.

Improper organization of the actin cytoskeleton affects protein synthesis at initiation

Although the actin cytoskeleton and the translation machinery are considered to be separate cellular complexes, growing evidence supports overlapping regulation of the two systems. Because of its interaction with actin, the eukaryotic translation elongation factor 1A (eEF1A) is proposed to be a regulator or link between these processes. Using a genetic approach with the yeast Saccharomyces cerevisiae, specific regions of eEF1A responsible for actin interactions and bundling were identified. Five new mutations were identified along one face of eEF1A. Dramatic changes in cell growth, cell morphology, and actin cable and patch formation as well as a unique effect on total translation in strains expressing the F308L or S405P eEF1A mutant form were observed. The translation effects do not correlate with reduced translation elongation but instead include an initiation defect. Biochemical analysis of the eEF1A mutant forms demonstrated reduced actin-bundling activity in vitro. Reduced total translation and/or the accumulation of 80S ribosomes in strains with either a mutation or a null allele of genes encoding actin itself or actin-regulating proteins Tpm1p, Mdm20p, and Bnirp/Bni1p was observed. Our data demonstrate that eEF1A, other actin binding proteins, and actin mutants affect translation initiation through the actin cytoskeleton.

The topographic distribution of the magnetic P100M to full- and half-field stimulation

Visual evoked magnetic responses were recorded to full-field and left and right half-field stimulation with three check sizes (70′, 34′ and 22′) in five normal subjects. Recordings were made sequentially on a 20-position grid (4 × 5) based on the inion, by means of a single-channel direct current-Superconducting Quantum Interference Device second-order gradiometer. The topographic maps were consistent on the same subjects recorded 2 months apart. The half-field responses produced the strongest signals in the contralateral hemisphere and were consistent with the cruciform model of the calcarine fissure. Right half fields produced upper-left-quadrant outgoing fields and lower-left-quadrant ingoing fields, while the left half field produced the opposite response. The topographic maps also varied with check size, with the larger checks producing positive or negative maximum position more anteriorly than small checks. In addition, with large checks the full-field responses could be explained as the summation of the two half fields, whereas full-field responses to smaller checks were more unpredictable and may be due to sources located at the occipital pole or lateral surface. In addition, dipole sources were located as appropriate with the use of inverse problem solutions. Topographic data will be vital to the clinical use of the visual evoked field but, in addition, provides complementary information to visual evoked potentials, allowing detailed studies of the visual cortex. © 1992 Kluwer Academic Publishers.

Exchange fairness and employee performance:An examination of the relationship between organizational politics and procedural justice

Data obtained from a manufacturing firm and a newspaper firm in India were used to examine the relationship between organizational politics and procedural justice in three separate studies. Study 1 constructively replicated research on the distinctiveness of the two constructs. Confirmatory factor analyses in which data from the manufacturing firm served as the development sample and data from the newspaper firm served as the validation sample demonstrated the distinctiveness of organizational politics and procedural justice. Study 2 examined the antecedents of the two constructs using data from the manufacturing firm. Structural equation modeling (SEM) results revealed formalization and participation in decision making to be positively related to procedural justice but negatively related to organizational politics. Further, authority hierarchy and spatial distance were positively related to organizational politics but unrelated to procedural justice. Study 3 examined the consequences of the two constructs in terms of task and contextual performance using data from the newspaper firm. Results of SEM analysis revealed procedural justice but not organizational politics to be related to task performance and the contextual performance dimensions of interpersonal facilitation and job dedication. © 2004 Elsevier Inc. All rights reserved.

Towards a semiology of the periodic review of UK regulated utilities

This note explores the regulatory process of UK privatised utilities through the periodic review of prices. It provides a brief history of the privatisation programme in the UK and the theoretical arguments for the price-cap regulation that has been used. It argues that regulatory process appears to involve a covert dialogue and exchange of information between the regulator and regulated and also a second separate review process that consists of an overt dialogue. Using a semiotic analysis the authors suggest that the unfolding of each of these overt reviews follows a very similar pattern that is constantly being re-enacted. It is concluded that further research is required into the relative importance of the two separate review processes in the setting of the price-cap.

Purification and crystallization of the hydroxylase component of the methanesulfonate monooxygenase from Methylosulfonomonas methylovora strain M2

The aim of the work described in this paper was two-fold: (1) the purification of the hydroxylase component of the MSAMO to electrophoretic homogeneity using a four-step chromatographic strategy and (2) the crystallization of the two-component hydroxylase of the MSAMO in order to enhance our understanding of the precise three-dimensional structure of the MSAMO, thus yielding an insight into the nature of the active site of this enzyme. Optimised crystallization conditions were identified allowing growth of crystals of the hydroxylase component of the MSAMO within five days. Crystals exhibited a brown colour suggesting the presence on an intact Rieske-iron sulfur centre and diffracted to 7.0 Å when a few degrees of data were evaluated on a beam line X11. © 2006 Elsevier Inc. All rights reserved.

An examination of the appropriateness of the contemporary strategic management models for the Greek small manufacturing enterprises

The starting point of the project was the observation that strategic management is absent in small businesses. The first objective of the project was to examine the reasons causing this situation in Greece, the second one, to examine the appropriateness of the contemporary models of strategic planning for the Greek S.M.E.s, and the third to examine the appropriateness of the alternative approaches to strategic management for the Greek S.M.E.s. The term appropriateness includes (a) the ability of managers to use the models and (b) the ability of the models to assist the managers. The results of the research indicate that none of the two above conditions exists, hence, it is suggested that the contemporary models of strategic management are inappropriate for the Greek S.M.E.s. Many previous research projects on the topic suggest that since the strategic decision making process in S.M.E.s is informal, the whole process is absent or ineffective. Current trends in S.M.E.s' strategic management do not consider the informality of the strategic decision making process as a kind of managerial illness, but as a managerial characteristic. The use of sophisticated data collection and analytical methods does not indicate successful strategic decisions, but it indicates the method large firms use to manage their strategy. According to the literature review, the S.M.E.s' managers avoid the use of the contemporary models of strategic management, because they do not have the knowledge, the resources or the time. Another thesis, expressed by some firms' specialists, suggests that small firms are different from large ones, hence their practice of strategic management should not follow the large firm's prototypes.

Comparing German and British political culture through values : and analysis of the values of health care reform

This research sets out to compare the values in British and German political discourse, especially the discourse of social policy, and to analyse their relationship to political culture through an analysis of the values of health care reform. The work proceeds from the hypothesis that the known differences in political culture between the two countries will be reflected in the values of political discourse, and takes a comparison of two major recent legislative debates on health care reform as a case study. The starting point in the first chapter is a brief comparative survey of the post-war political cultures of the two countries, including a brief account of the historical background to their development and an overview of explanatory theoretical models. From this are developed the expected contrasts in values in accordance with the hypothesis. The second chapter explains the basis for selecting the corpus texts and the contextual information which needs to be recorded to make a comparative analysis, including the context and content of the reform proposals which comprise the case study. It examines any contextual factors which may need to be taken into account in the analysis. The third and fourth chapters explain the analytical method, which is centred on the use of definition-based taxonomies of value items and value appeal methods to identify, on a sentence-by-sentence basis, the value items in the corpus texts and the methods used to make appeals to those value items. The third chapter is concerned with the classification and analysis of values, the fourth with the classification and analysis of value appeal methods. The fifth chapter will present and explain the results of the analysis, and the sixth will summarize the conclusions and make suggestions for further research.

The slope of the psychometric function and non-stationarity of thresholds in spatiotemporal contrast vision

The slope of the two-interval, forced-choice psychometric function (e.g. the Weibull parameter, ß) provides valuable information about the relationship between contrast sensitivity and signal strength. However, little is known about how or whether ß varies with stimulus parameters such as spatiotemporal frequency and stimulus size and shape. A second unresolved issue concerns the best way to estimate the slope of the psychometric function. For example, if an observer is non-stationary (e.g. their threshold drifts between experimental sessions), ß will be underestimated if curve fitting is performed after collapsing the data across experimental sessions. We measured psychometric functions for 2 experienced observers for 14 different spatiotemporal configurations of pulsed or flickering grating patches and bars on each of 8 days. We found ß ˜ 3 to be fairly constant across almost all conditions, consistent with a fixed nonlinear contrast transducer and/or a constant level of intrinsic stimulus uncertainty (e.g. a square law transducer and a low level of intrinsic uncertainty). Our analysis showed that estimating a single ß from results averaged over several experimental sessions was slightly more accurate than averaging multiple estimates from several experimental sessions. However, the small levels of non-stationarity (SD ˜ 0.8 dB) meant that the difference between the estimates was, in practice, negligible.

Phase discrimination and simultaneous frequency conversion of the orthogonal components of an optical signal by four-wave mixing in an SOA

Simultaneous conversion of the two orthogonal phase components of an optical input to different output frequencies has been demonstrated by simulation and experiment. A single stage of four-wave mixing between the input signal and four pumps derived from a frequency comb was employed. The nonlinear device was a semiconductor optical amplifier, which provided overall signal gain and sufficient contrast for phase sensitive signal processing. The decomposition of a quadrature phase-shift keyed signal into a pair of binary phase-shift keyed outputs at different frequencies was also demonstrated by simulation.

Analysis of the pore of the unusual major intrinsic protein channel, yeast Fps1p

Fps1p is a glycerol efflux channel from Saccharomyces cerevisiae. In this atypical major intrinsic protein neither of the signature NPA motifs of the family, which are part of the pore, is preserved. To understand the functional consequences of this feature, we analyzed the pseudo-NPA motifs of Fps1p by site-directed mutagenesis and assayed the resultant mutant proteins in vivo. In addition, we took advantage of the fact that the closest bacterial homolog of Fps1p, Escherichia coli GlpF, can be functionally expressed in yeast, thus enabling the analysis in yeast cells of mutations that make this typical major intrinsic protein more similar to Fps1p. We observed that mutations made in Fps1p to "restore" the signature NPA motifs did not substantially affect channel function. In contrast, when GlpF was mutated to resemble Fps1p, all mutants had reduced activity compared with wild type. We rationalized these data by constructing models of one GlpF mutant and of the transmembrane core of Fps1p. Our model predicts that the pore of Fps1p is more flexible than that of GlpF. We discuss the fact that this may accommodate the divergent NPA motifs of Fps1p and that the different pore structures of Fps1p and GlpF may reflect the physiological roles of the two glycerol facilitators.