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Sample records for karin persson waller

  1. Superculture? Thoughts Prompted by Roland S. Persson's Essay

    ERIC Educational Resources Information Center

    Tebbs, Trevor J.

    2012-01-01

    The author finds Roland S. Persson's (2012a) paper to be timely, fascinating, important and powerful. At risk of mixing metaphors, it provides much food for thought and a penetrating lens through which all those vested in the optimal realisation of human potential would be prudent to review their own perceptions, boundaries of belief and…

  2. Photometry of Karin family asteroids

    NASA Astrophysics Data System (ADS)

    Hahn, G.; Mottola, S.; Sen, A. K.; Harris, A. W.; Kührt, E.; Mueller, M.

    2006-12-01

    We have performed photometric observations in the V-band of two asteroids belonging to the Karin asteroid family, (11728) Einer and (93690) 2000 VE21 , using the 2-m Himalayan Chandra Telescope, Hanle and 2k ×4k pixels CCD imager. We obtained measurements during two nights (November 25 and 26, 2005) which enabled information on the rotational periods and the lightcurve amplitudes of the asteroids to be derived. In addition, we derived the absolute magnitudes H, improving previously published values. These observations were performed to complement the IR observations obtained for a set of Karin family asteroids with the Spitzer space telescope.

  3. 832 Karin: Absence of rotational spectral variations

    NASA Astrophysics Data System (ADS)

    Vernazza, Pierre; Rossi, Alessandro; Birlan, Mirel; Fulchignoni, Marcello; Nedelcu, Alin; Dotto, Elisabetta

    2007-11-01

    832 Karin is the largest member of the young Karin cluster that formed 5.75±0.05 Myr ago in the outer main belt. Surprisingly, recent near-IR spectroscopy measurements [Sasaki, T., Sasaki, S., Watanabe, J., Sekiguchi, T., Yoshida, F., Kawakita, H., Fuse, T., Takato, N., Dermawan, B., Ito, T., 2004. Astrophys. J. 615 (2), L161-L164] revealed that Karin's surface shows different colors as a function of rotational phase. It was interpreted that 832 Karin shows us the reddish space-weathered exterior surface of the parent body as well as an interior face, which has not had time to become space-weathered. This result is at odds with recent results including seismic and geomorphic modeling, modeling of the Karin cluster formation and measurements of the space weathering rate. Consequently, we aimed to confirm/infirm this surprising result by sampling Karin's spectrum well throughout its rotation. Here, we present new visible (0.45-0.95 μm) and near-infrared (0.7-2.5 μm) spectroscopic observations of 832 Karin obtained in January and April 2006, covering most of Karin's longitudes. In the visible range, we find that Karin shows no rotational spectral variations. Similarly, we find that Karin exhibits very little (to none) spectral variations with rotation in the near-IR range. Our results imply that 832 Karin has a homogeneous surface, in terms of composition and surface age. Our results also imply that the impact that generated the family refreshed entirely Karin's surface, and probably the surfaces of all members.

  4. The Spin Vector of (832) Karin

    NASA Astrophysics Data System (ADS)

    Slivan, Stephen M.; Molnar, L. A.

    2010-10-01

    We observed rotation lightcurves of Koronis family and Karin cluster member (832) Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of 18.352 h, spin obliquity near 41°, and pole ecliptic longitude near either 51° or 228°. Although the two ambiguous pole solutions are near the clustered pole solutions of four Koronis family members whose spins are thought to be trapped in a spin-orbit resonance (Vokrouhlický et al., 2003), Karin does not seem to be trapped in the resonance; this is consistent with the expectation that the 6 My age of Karin (Nesvorný et al., 2002) is too young for YORP torques to have modified its spin since its formation. The spin vector and shape results for Karin will constrain family formation models that include spin properties, and we discuss the Karin results in the context of the other members of the Karin cluster, the Karin parent body, and the parent body's siblings in the Koronis family.

  5. Drawings of fossils by Robert Hooke and Richard Waller

    PubMed Central

    Kusukawa, Sachiko

    2013-01-01

    The drawings of fossils by Robert Hooke and Richard Waller that were the basis of the engravings in Hooke's Posthumous works (1705) are published here for the first time. The drawings show that both Hooke and Waller were proficient draftsmen with a keen eye for the details of petrified objects. These drawings provided Hooke with a polemic edge in making the case for the organic origins of ‘figured stones’.

  6. Spitzer Survey of the Karin Cluster Asteroids

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-10-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to derive accurate sizes and study the physical properties of their surfaces. The albedos of the observed Karins appear to be very similar. The albedos, pv, have a mean of 0.17 and a standard deviation of 0.04, compared to pv = 0.15 ± 0.05 for 832 Karin itself (for H = 11.2 ± 0.3). The derived diameters range from 20 km for 832 Karin to 1.9 km for 93690, with uncertainties of 10%. The Karins data show no evidence of albedo dependence on size, and the small range of albedos is consistent with all program targets being S-type bodies. There is some evidence for higher values of thermal inertia amongst the smaller family members, which may be indicative of coarser regolith. These results are preliminary, pending outstanding Spitzer observations and further analysis. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  7. 832 Karin Shows No Rotational Spectral Variations

    NASA Astrophysics Data System (ADS)

    Chapman, Clark R.; Enke, B.; Merline, W. J.; Nesvorny, D.; Tamblyn, P.; Young, E. F.

    2006-09-01

    Sasaki et al. (2004, 2005) claimed that 832 Karin, the brightest member of the very young (5.75 Myr) Karin cluster of the Koronis family, shows dramatically different colors as a function of rotational phase. It was interpreted that Karin is a fragment of the recently broken-up asteroid, showing the reddish space-weathered exterior surface of the precursor asteroid as well as an interior face, which has not had time to become space-weathered. On five nights during UT 7-14 January 2006, we observed Karin with the SpeX instrument, 0.8-2.5 microns, on the IRTF. We sampled its spectrum well throughout its rotation. We analyzed the data in 50 deg. intervals of rotational longitude; some longitudes were sampled during two different nights. We find that Karin exhibits minimal spectral variations with rotation, certainly nothing of the magnitude reported by Sasaki et al. Since our data resemble Sasaki et al.'s "blue" and "green" sets, we suggest that their "red" set is spurious. Indeed, it is difficult to understand how the reported color change could have occurred during such a modest interval ( 4%) of rotational longitude. (Note that we have not determined Karin's pole position nor the phase of the Sasaki et al. data within our own coverage, so the refutation of dramatic color change is not absolutely secure.) Karin and its family members are not quite as red as typical S-types, yet have shallow absorption bands. Perhaps the space-weathering process affecting these young asteroids has had time to reduce spectral contrast, but has not operated long enough to redden them -- an intermediate case of space weathering, which has gone to completion for older main-belt asteroids of these sizes. Supported by the NASA Planetary Astronomy Program. T. Sasaki et al. 2004. ApJ 615, L161-L164; T. Sasaki et al. 2005. LPSC XXXVI, 1590.pdf.

  8. Spectroscopic characterization of the Karin family

    NASA Astrophysics Data System (ADS)

    Vernazza, P.; Fulchignoni, M.; Birlan, M.; Dotto, E.; Rossi, A.; Fornasier, S.; Marzari, F.; Nesvorny, D.

    2005-08-01

    The Karin asteroidal family was firstly identified by Nesvorny et al. (2002, Nature 417) who numerically integrated the orbits of 39 known members. More recently Nesvorny and Bottke (2004) analyzed a wider sample of objects and, taking into account also the Yarkovsky effect, identified the common origin of 90 family members at 5.75±0.05 Myr in the past. This is an exceptionally young age for an asteroid family. In fact, other known families are thought to be much older, 100 Myr to Gyrs old. We carried out visible and near-infrared spectroscopy of several members of the Karin family. We observed 5 member of the Karin family on November 2003 using the IRTF telescope. These data confirm that 832 Karin is an S-type asteroid (as indicated by Binzel, private communication), characterized by strong absorption features of olivine and pyroxene at about 1 and 2 μ m. Visible spectra for 20 objects were later obtained in December, 2004 with EMMI/NTT (ESO, La Silla) and with MOS/CFHT (Mauna Kea, Hawaii). Fifteen of these objects (832 Karin among them), have S-type spectra with the maximum of each spectra located at a very similar wavelength. This result sustain the hypothesis of a common origin. Five other spectra obtained seem rather primitive (B,C types). We analysed the spectra of the Karin cluster in the context of the Koronis family. This analysis reveals that the spectra are less red than those of the Koronis members. Moreover, we can interpret them as less mature surfaces. Finally, we made an interpretation of the surface composition of 832 Karin, using the Shkuratov scattering model.

  9. Culture, Globalisation and the Study of Giftedness: Reflections on Persson's Analysis and Recommendations for Future Research

    ERIC Educational Resources Information Center

    Foreman, Jennifer; Renzulli, Joseph

    2012-01-01

    Dr. Persson's (2012a) target article addresses a number of key points that will greatly impact the study of giftedness, gifted education, and talent development in the "flat" world of the 21st century and beyond. Research in these areas needs to continually reflect upon changes in the social world outside its narrow purview to validate its…

  10. Policy, Practice in Giftedness, and Research Methodologies: Response to Roland S. Persson's Article

    ERIC Educational Resources Information Center

    Matthews, Dona J.

    2012-01-01

    The author finds the target article "Cultural Variation and Dominance in a Globalised Knowledge Economy" to be a thoughtful exploration of an important topic for all social scientists, certainly including those who study gifted development and education. Roland S. Persson (2012a) raises many questions about policy and practice in giftedness…

  11. Spin vectors in the Koronis family: III. (832) Karin

    NASA Astrophysics Data System (ADS)

    Slivan, Stephen M.; Molnar, Lawrence A.

    2012-08-01

    Studies of asteroid families constrain models of asteroid collisions and evolution processes, and the Karin cluster within the Koronis family is among the youngest families known (Nesvorný, D., Bottke, Jr., W.F., Dones, L., Levison, H.F. [2002]. Nature 417, 720-722). (832) Karin itself is by far the largest member of the Karin cluster, thus knowledge of Karin's spin vector is important to constrain family formation and evolution models that include spin, and to test whether its spin properties are consistent with the Karin cluster being a very young family. We observed rotation lightcurves of Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of (18.352 ± 0.003) h, spin obliquity near (42 ± 5)°, and pole ecliptic longitude near either (52 ± 5)° or (230 ± 5)°. The spin vector and shape results for Karin will constrain models of family formation that include spin properties; in the meantime we briefly discuss Karin's own spin in the context of those of other members of the Karin cluster and the parent body's siblings in the Koronis family.

  12. Lightcurves of the Karin family asteroids

    NASA Astrophysics Data System (ADS)

    Yoshida, Fumi; Ito, Takashi; Dermawan, Budi; Nakamura, Tsuko; Takahashi, Shigeru; Ibrahimov, Mansur A.; Malhotra, Renu; Ip, Wing-Huen; Chen, Wen-Ping; Sawabe, Yu; Haji, Masashige; Saito, Ryoko; Hirai, Masanori

    2016-05-01

    The Karin family is a young asteroid family formed by an asteroid breakup 5.8 Myr ago. Since the members of this family probably have not experienced significant orbital or collisional evolution yet, it is possible that they still preserve properties of the original family-forming event in terms of their spin state. We carried out a series of photometric observations of the Karin family asteroids, and here we report on the analysis of the lightcurves including the rotation period of eleven members. The mean rotation rate of the Karin family members turned out to be much lower than those of near-Earth asteroids or small main belt asteroids (diameter D < 12 km), and even lower than that of large main belt asteroids (D > 130 km). We investigated a correlation between the peak-to-trough variation and the rotation period of the eleven Karin family asteroids, and found a possible trend that elongated members have lower spin rates, and less elongated members have higher spin rates. However, this trend has to be confirmed by another series of future observations.

  13. Karin cluster formation by asteroid impact

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Enke, Brian L.; Bottke, William F.; Durda, Daniel D.; Asphaug, Erik; Richardson, Derek C.

    2006-08-01

    Insights into collisional physics may be obtained by studying the asteroid belt, where large-scale collisions produced groups of asteroid fragments with similar orbits and spectra known as the asteroid families. Here we describe our initial study of the Karin cluster, a small asteroid family that formed 5.8±0.2 Myr ago in the outer main belt. The Karin cluster is an ideal 'natural laboratory' for testing the codes used to simulate large-scale collisions because the observed fragments produced by the 5.8-Ma collision suffered apparently only limited dynamical and collisional erosion. To date, we have performed more than 100 hydrocode simulations of impacts with non-rotating monolithic parent bodies. We found good fits to the size-frequency distribution of the observed fragments in the Karin cluster and to the ejection speeds inferred from their orbits. These results suggest that the Karin cluster was formed by a disruption of an ≈33-km-diameter asteroid, which represents a much larger parent body mass than previously estimated. The mass ratio between the parent body and the largest surviving fragment, (832) Karin, is ≈0.15-0.2, corresponding to a highly catastrophic event. Most of the parent body material was ejected as fragments ranging in size from yet-to-be-discovered sub-km members of the Karin cluster to dust grains. The impactor was ≈5.8 km across. We found that the ejections speeds of smaller fragments produced by the collision were larger than those of the larger fragments. The mean ejection speeds of >3-km-diameter fragments were ≈10 ms. The model and observed ejection velocity fields have different morphologies perhaps pointing to a problem with our modeling and/or assumptions. We estimate that ˜5% of the large asteroid fragments created by the collision should have satellites detectable by direct imaging (separations larger than 0.1 arcsec). We also predict a large number of ejecta binary systems with tight orbits. These binaries, located in the

  14. An "Immanent" Social Class Effect on Participation in Higher Education? A Rejoinder to Harrison and Waller

    ERIC Educational Resources Information Center

    Noble, John; Davies, Peter

    2010-01-01

    This article responds to criticisms, put forward by Harrison and Waller in this issue, of an earlier paper by Noble and Davies. In particular, we argue that our interpretation of earlier quantitative research is correct, that Harrison and Waller have misconstrued the purpose of our previous paper and the analysis it contains, and that they…

  15. The Black American Press and the New Manifest Destiny: The Waller Affair

    ERIC Educational Resources Information Center

    Woods, Randall B.

    1977-01-01

    In 1895 the United States and France became involved in a dispute concerning the arrest and imprisonment of one John L. Waller, a black American who dared to challenge French imperialism in Madagascar. The black press, perhaps at the height of its power and influence, reacted vigorously to Waller and his goals, and to the Cleveland…

  16. Risk, Russian-roulette and lotteries: Persson and Savulescu on moral enhancement.

    PubMed

    Gunson, Darryl; McLachlan, Hugh

    2013-11-01

    The literature concerning the possibility and desirability of using new pharmacological and possible future genetic techniques to enhance human characteristics is well-established and the debates follow some well-known argumentative patterns. However, one argument in particular stands out and demands attention. This is the attempt to tie the moral necessity of moral enhancement to the hypothesised risks that allowing cognitive enhancement will bring. According to Persson and Savulescu, cognitive enhancement should occur only if the risks they think it to poses are mitigated by moral enhancement. By this they mean the compulsory and universal amplification of the disposition of altruism and the inflation of our sense of fairness, by chemical and/or genetic means. Their claim is important, intriguing and unsettling. This paper focuses on three central, but relatively neglected, features of their argument. First, there is a pernicious ambiguity in the language of 'risk' used by Persson and Savulescu where they tend to conflate 'risk' and 'uncertainty'. Second, their use of the lottery analogy to render their position more plausible is unconvincing. It tends to distort rather than illuminate the relevant considerations. Third, Persson and Savulescu do not adequately take into account the social and individual benefits that enhancing cognition could have. If they did, it would be apparent that those benefits alone would outweigh the considerations used to justify accompanying CE with ME. PMID:23277383

  17. Age of the Karin Cluster of Asteroids

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Knezevic, Z.; Cellino, A.; Dell'Oro, A.

    2005-12-01

    The Karin Cluster, the youngest known asteroid family, was formed by a catastrophic disruption event about 5.8 million years ago. We have undertaken extensive numerical orbital integrations to confirm and refine the cluster age and to refine cluster membership. The Karin Cluster is important because its members have a precisely known, common formation age, enabling new tests of models for asteroid fragmentation, orbital evolution, surface space weathering, and regolith formation and evolution, but it is necessary to distinguish cluster members from background objects in a densely populated region of the main asteroid belt, close to the center of the Koronis family. We have performed full orbital integrations of 122 numbered asteroids backwards in time over the last 10 million years, to calculate filtered mean Keplerian elements at 500 year time resolution. These calculations show that the age of the Karin cluster is 5.7635 ± 0.0005 Myr, consistent with prior work. The calculations also confirm 54 numbered asteroids as cluster members, and they identify as interlopers some objects included in previous cluster lists.

  18. Revealing Additional Dimensions of Globalisation and Cultural Hegemony: A Response to Roland S. Persson's Call for Cultural Sensitivity in Gifted Studies

    ERIC Educational Resources Information Center

    Ambrose, Don

    2012-01-01

    In this commentary, the author finds the interdisciplinary approach of Roland S. Persson's (2012a) target article refreshing. Persson's (2012a) additional emphases on ethnocentricity, cultural bias and strong threads of influence from the global economy also are helpful. They shed light on some strong contextual influences that shape the…

  19. Color Variation of a Very Young Asteroid, Karin

    NASA Astrophysics Data System (ADS)

    Ito, Takashi; Yoshida, Fumi

    2007-02-01

    We present current results of our long-term campaign to make photometric observations of the new-born Karin family asteroids, especially those of (832) Karin. Karin, an S-type main-belt asteroid, is the largest member of the Karin family. This asteroid is likely a large fragment of a disruption event in the main asteroid belt that occurred about 5.8 million years ago. We obtained multi-color photometric observations of this asteroid in 2003 and 2004. We have reported a potential surface color variation of this asteroid, which indicates the existence of both mature and fresh surfaces on it. However, as of 2004 September, this asteroid apparently does not show a strong surface color difference, which might give us some insight into its spin axis orientation and shape. This is quite an interesting result, but it has to be confirmed by future observations.

  20. Physical characterization of the Karin family

    NASA Astrophysics Data System (ADS)

    Vernazza, P.; Birlan, M.; Rossi, A.; Dotto, E.; Nesvorny, D.; Brunetto, R.; Fornasier, S.; Fulchignoni, M.; Renner, S.

    2006-12-01

    Aims.The Karin cluster is a small asteroid family that formed 5.8 ± 0.2 Myr ago in the outer main belt. This is an exceptionally young age for an asteroid family. To investigate the composition and homogeneity of the members of this family, we started a spectroscopic survey in the visible and in the near-IR. Methods: .We observed 24 Karin asteroid members in the visible and 6 members in the near-IR. Results: .In the visible range, all the objects share the same characteristics: a maximum around λ = 0.75 μm, and a spectral slope spanning a continuous but limited range; in the NIR, our spectra show a similar behaviour. Our results suggest global homogeneity of the parent body and none of the investigated objects seems to be an interloper. These results are consistent with the dynamical hypothesis of a common origin. Finally, the range of spectral slopes is similar with the range of slopes for OC meteorites. We interpret this result as an indication of a low degree of spatial alteration for the observed surfaces. This result is coherent with the young age of the family.

  1. An experimental 'Life' for an experimental life: Richard Waller's biography of Robert Hooke (1705).

    PubMed

    Moxham, Noah

    2016-03-01

    Richard Waller's 'Life of Dr Robert Hooke', prefixed to his edition of Hooke's Posthumous Works (1705), is an important source for the life of one of the most eminent members of the early Royal Society. It also has the distinction of being one of the earliest biographies of a man of science to be published in English. I argue that it is in fact the first biography to embrace the subject's natural-philosophical work as the centre of his life, and I investigate Waller's reasons for adopting this strategy and his struggle with the problem of how to represent an early experimental philosopher in print. I suggest that Waller eschews the 'Christian philosopher' tradition of contemporary biography - partly because of the unusually diverse and fragmentary nature of Hooke's intellectual output - and draws instead upon the structure of the Royal Society's archive as a means of organizing and understanding Hooke's life. The most quoted phrase from Waller's biography is that Hooke became 'to a crime close and reserved' in later life; this essay argues that Waller's biographical sketch was fashioned in order to undo the effects of that reserve. In modelling his approach very closely on the structure of the society's records he was principally concerned with making Hooke's work and biography accessible, intelligible and useful to the fellowship in a context familiar to them, a context which had provided the institutional framework for most of Hooke's adult life. I argue that Waller's 'Life' was also intended to make the largest claims for Hooke's intellectual standing that the author dared in the context of the enmity between Hooke and Isaac Newton once the latter became president of the Royal Society. However, I also adduce fresh manuscript evidence that Waller actually compiled, but did not publish, a defence of Hooke's claim to have discovered the inverse square law of gravity, allowing us to glimpse a much more assertive biography of Hooke than the published version. PMID

  2. Temperature dependence of Debye-Waller factor in dye-doped polymers

    NASA Astrophysics Data System (ADS)

    Saikan, S.; Imaoka, A.; Kanematsu, Y.; Sakoda, K.; Kominami, K.; Iwamoto, M.

    1990-02-01

    The temperature dependence of the Debye-Waller factor in dye-doped polymers has been investigated with femtosecond accumulated photon echo. The superiority of polyvinyl alcohol as the host polymer for the optical-memory material is ascribed to the higher phonon sideband frequency in this sample. It is pointed out that the temperature dependence of the Debye-Waller factor, in particular the phonon sideband frequency, is of fundamental importance to finding out the best polymer for high-temperature optical memory based on photochemical hole burning.

  3. John Dewey and the Question of Race: The Fight for Odell Waller

    ERIC Educational Resources Information Center

    Stack, Sam F., Jr.

    2009-01-01

    In an attempt to better understand the complexity of American racism and democracy, this paper explores racism through the plight of an African American sharecropper, Odell Waller, and the reaction and involvement of John Dewey, America's most liberal democratic philosopher of the 20th century. This exploration delves into the nature of American…

  4. Willard Waller's Sociology of Teaching Reconsidered: "What Does Teaching Do to Teachers?"

    ERIC Educational Resources Information Center

    Pajak, Edward F.

    2012-01-01

    Willard Waller's (1932/1976) classic account of what teaching does to teachers is examined through the lens of psychoanalytic theory in conjunction with Ovid's myth of Narcissus. Parallel themes within the two texts are analyzed and interpreted as suggesting that narcissistic psychological processes played a part in distorting teachers'…

  5. Calculation of the Debye-Waller factor for atom-surface scattering: He on Ag(111)

    NASA Astrophysics Data System (ADS)

    Idiodi, J.; Bortolani, V.; Franchini, A.; Santoro, G.; Celli, V.

    1987-04-01

    By a consistent application of the distorted-wave Born approximation, the Debye-Waller exponent for the scattering of He atoms from the Ag(111) surface is directly computed. When diffraction is negligible, as in this case, the decrease in specular intensity is simply obtained by summing the scattering due to all possible one-phonon processes. Using one-phonon computed intensities that agree with experiment along high-symmetry directions of the surface Brillouin zone, we find that the computed Debye-Waller exponent agrees with experiment and corresponds to an effective Debye temperature of 241 K. All corrections to the eikonal-type formula, 2W=4p2z, are automatically included. In particular, the contribution of phonons with high parallel momentum is sharply cut off.

  6. VizieR Online Data Catalog: Properties of asteroids in Karin cluster (Carruba+, 2016)

    NASA Astrophysics Data System (ADS)

    Carruba, V.; Nesvorny, D.; Vokrouhlicky, D.

    2016-07-01

    Many new asteroids have been discovered since the last dynamical analysis of the Karin cluster. Here we repeat the analysis of Nesvorny & Bottke (2004Icar..170..324N) with an orbital catalog that contains nearly seven times more asteroids than there were available back in 2004. We revise the Karin family membership by applying the usual clustering method on the new orbital catalog. The taxonomical and albedo interlopers are eliminated. We then apply a more stringent criterion of the Karin family membership by requiring that orbits converged with each other ~5.75Myr ago. In Table1, we report the list of 480 identified Karin cluster members. (1 data file).

  7. Self-consistent Debye-Waller factors of the electron solid on liquid helium

    NASA Astrophysics Data System (ADS)

    Namaizawa, H.

    1980-05-01

    Based on the self-consistent field formalism we propose a shear-mode self-consistency for the high-frequency Debye-Waller factors (HFDWF) of the electron solid bound on a free surface of liquid helium. Our results are qualitatively in agreement with the empirical DW factor determined by Fisher, Halperin, and Platzman with the experiment of Grimes and Adams. We also report the analysis of the HFDWF according to the Lindemann law.

  8. Who invented the dichotomous key? Richard Waller's watercolors of the herbs of Britain.

    PubMed

    Griffing, Lawrence R

    2011-12-01

    On 27 March 1689, Richard Waller, Fellow and Secretary of the Royal Society presented his "Tables of the English Herbs reduced to such an order, as to find the name of them by their external figures and shapes" to his assembled colleagues at a meeting of the Royal Society. These tables were developed for the novice by being color images, composed in pencil and watercolor, of selected plants and their distinguishing characteristics. The botanical watercolors for the tables are now a Turning-the-Pages document online on the website of the Royal Society. However, for the past 320 years, the scientific context for the creation of these outstanding botanical watercolors has remained obscure. These tables were developed by Waller as an image-based dichotomous key, pre-dating by almost 100 years the text-based dichotomous keys in the first edition of Flora Française (1778) by Jean Baptiste Lamarck, who is generally given priority for the development of the dichotomous key. How these large folio images were arranged to illustrate a dichotomous key is unknown, but an arrangement based on Waller's description is illustrated here as leaf-ordering for the separate hierarchical clusters (tables). Although only 24 species of watercolored dicot herbs out of a total of 65 in the set of watercolors (the others being monocots) are used in these tables, they are a "proof of concept", serving as models upon which a method is based, that of using a key composed of dichotomous choices for aiding identification. PMID:22074776

  9. Young Asteroid 832 Karin shows no rotational spectral variations

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.; Enke, B.; Merline, W. J.; Tamblyn, P.; Nesvorný, D.; Young, E. F.; Olkin, C.

    2007-11-01

    We have made near-IR spectral observations of the very young (5.75 Myr) S-type asteroid 832 Karin, well sampled in rotational phase over its 18.35-h period. We find no significant variations in its reflectance spectrum. Karin, the brightest member of the Karin cluster (a sub-family of the larger, older Koronis dynamical family), was shown to be exceptionally young by Nesvorný et al. [Nesvorný, D., Bottke, W.F., Dones, L., Levison, H., 2002. Nature 417, 720-722], using backward numerical integration of orbital elements of cluster members. Their precise dating of the collisional breakup gives us an opportunity, for the first time and without age-dating of physical samples, to monitor time-evolution of processes, like space weathering, that operate on timescales of ˜1-10 Myr. Sasaki et al. [Sasaki, T., Sasaki, S., Watanabe, J., Sekiguchi, T., Yoshida, F., Kawakita, H., Fuse, T., Takato, N., Dermawan, B., Ito, T., 2004. Astrophys. J. 615, L161-L164; Sasaki, T., Sasaki, S., Watanabe, J., Sekiguchi, T., Yoshida, F., Ito., T., Kawakita, H., Fuse, T., Takato, N., Dermawan, B., 2005. Lunar Planet. Sci. XXXVI. Abstract #1590] had made similar measurements of Karin, although more sparsely sampled than ours, and claimed dramatically different colors as a function of rotational phase. Sasaki et al. interpreted their data to be showing the reddish, space-weathered exterior surface of the precursor asteroid, as well as an interior face, which had not had time to become space-weathered. On five nights over 2006 January 7-14 UT, we observed Karin with the SpeX (0.8-2.5 μm) spectrometer of the IRTF. We analyze data in 30° intervals of rotational longitude, some of which we sampled on two different nights. The spectra are consistent with little or no spectral variation as the asteroid rotates; certainly there are no changes as large as previously reported. The previous observations were probably spurious. Our average spectrum resembles the "blue" spectrum of Sasaki et al., which

  10. A Surrogate for Debye-Waller Factors from Dynamic Stokes Shifts

    PubMed Central

    Zhong, Qin; Johnson, Jerainne; Aamer, Khaled A.; Tyagi, Madhusudan

    2011-01-01

    We show that the short-time behavior of time-resolved fluorescence Stokes shifts (TRSS) are similar to that of the intermediate scattering function obtained from neutron scattering at q near the peak in the static structure factor for glycerol. This allows us to extract a Debye-Waller (DW) factor analog from TRSS data at times as short as 1 ps in a relatively simple way. Using the time-domain relaxation data obtained by this method we show that DW factors evaluated at times ≥ 40 ps can be directly influenced by α relaxation and thus should be used with caution when evaluating relationships between fast and slow dynamics in glassforming systems. PMID:21701673

  11. Measuring Order and the Debye-Waller Factor for Porous Arrays

    NASA Astrophysics Data System (ADS)

    Kaatz, Forrest; Bultheel, Adhemar; Egami, Takeshi

    2007-03-01

    We derive methods that explain how to quantify the amount of order in ``ordered'' and ``highly ordered'' porous arrays. Ordered arrays from bee honeycomb and several from the general field of nanoscience are compared. Accurate measures of the order in porous arrays are made using the discrete radial distribution function (RDF) and the Debye-Waller Factor (DWF) from 2-D discrete Fourier transforms calculated from the real-space data using MATLAB routines. Nanoporous anodized aluminum oxide, hexagonal arrays from functional materials, hexagonal arrays from nanosphere lithography, and arrays from block copolymer lithography (all taken from the literature) are compared to two-dimensional model systems. The DWF is normalized to the first harmonic and depends on N, the number of peaks in the fit for these finite arrays. We optimize N to the classical model for the DWF as a fit to reciprocal space K^2.

  12. The anomalous Debye-Waller factor and the fragility of glasses

    NASA Astrophysics Data System (ADS)

    Roland, C. M.; Ngai, K. L.

    1996-02-01

    The correlation between the magnitude of the Debye-Waller anomaly and the temperature dependence of the relaxation time and viscosity of glass-forming liquids (i.e., their fragility) is investigated using the coupling model of relaxation. The correlation is shown to be a natural consequence of the relationship between the noncooperative and intermolecularly cooperative relaxation times of the model. Specifically, the deviation of the mean squared displacement from a linear temperature dependency increases as the fragility (in the Angell sense) of the glass-forming liquid increases because more fragile glasses exhibit substantially more short-time, noncooperative relaxation. This latter fact arises from their shorter noncooperative relaxation times, as deduced from the coupling model.

  13. A newborn asteroid 832 Karin with old and new surfaces SUBARU spectroscopy

    NASA Astrophysics Data System (ADS)

    Sasaki, Sho; Sasaki, Takanori; Watanabe, Jun-ichi; Yoshida, Fumi; Kawakita, Hideyo; Takato, Naruhisa; Dermawan, Budi; Fuse, Tetsuharu; Ito, Takashi; Sekiguchi, Tomohiko

    2006-01-01

    The mismatch between reflectance spectra of most common asteroids (S-type asteroids) and most common meteorites (ordinary chondrites) is thought to be caused by space weathering. Recent study of celestial mechanics has led to the discovery of a young group of S-type asteroids, "Karin cluster group", which is thought to be remnants of a collisional breakup only 5.8 million years ago. We performed near-infrared spectroscopy of the brightest asteroid 832 Karin among this cluster group. For different rotational phases of Karin, we derived different spectra such as reddened spectrum like that of S-type asteroid and unreddened spectrum like that of ordinary chondrites. These findings indicate that a part of Karin may retain spectrally mature surface of its parent body. Although Karin might have formed from gravitational accumulation from catastrophic collision of its parent body, there would be some color heterogeneity on its surface if Karin collected materials which derived the weathered surface of the parent body.

  14. A Robust Survey of the Physical Properties of the Karin Cluster Asteroids

    NASA Astrophysics Data System (ADS)

    Harris, Alan; Cheng, Andrew; Fitzsimmons, Alan; Hicks, Michael; Lisse, Carey; Lowry, Stephen; Mueller, Michael; Osip, Dave

    2005-06-01

    The Karin cluster is by far the youngest known family of main-belt asteroids, dating back to a collisional event only 5.8+/-0.2 Myr ago. We propose to sample the thermal continua of 17 Karin cluster asteroids of different sizes, down to the smallest members discovered so far, in order to derive accurate sizes and study the physical properties of their surfaces. Our aims include a study of trends in thermal inertia and albedo with size. The analysis will be based on sophisticated thermal models that will provide important insight into thermal inertia and regolith coverage. The widely used 'standard thermal model' leads to serious errors in thermal studies of small asteroids and is not adequate for a detailed study of the physical characteristics of Karin cluster members. The following questions are amongst those addressed by this program: 1. Are the distributions of sizes and albedos compatible with the Karin cluster being the result of a single catastrophic collision 5.8+/-0.2 Myr ago (Nesvorny et al., 2002)? 2. Are the sizes and thermal properties of the Karin-cluster members compatible with the claim of Nesvorny and Bottke (2004) that the Yarkovsky Effect is responsible for an apparent non-gravitational drift of their orbital motion? 3. Does the retention of a significant thermally insulating layer of regolith depend on asteroid size? If so, what are the consequences for modeling the Yarkovsky effect and the delivery of main-belt asteroids into near-Earth orbits? 4. Is there a correlation between albedo and size among the Karin cluster members similar to that evident for near-Earth asteroids in the same size range? If so, what are the consequences for models of age-dependent space weathering? (the Karin cluster members all have the same age).

  15. Search for anisotropy in the Debye-Waller factor of HCP solid 4He

    NASA Astrophysics Data System (ADS)

    Barnes, Ashleigh L.; Hinde, Robert J.

    2016-02-01

    The properties of hexagonal close packed (hcp) solid 4He are dominated by large atomic zero point motions. An accurate description of these motions is therefore necessary in order to accurately calculate the properties of the system, such as the Debye-Waller (DW) factors. A recent neutron scattering experiment reported significant anisotropy in the in-plane and out-of-plane DW factors for hcp solid 4He at low temperatures, where thermal effects are negligible and only zero-point motions are expected to contribute. By contrast, no such anisotropy was observed either in earlier experiments or in path integral Monte Carlo (PIMC) simulations of solid hcp 4He. However, the earlier experiments and the PIMC simulations were both carried out at higher temperatures where thermal effects could be substantial. We seek to understand the cause of this discrepancy through variational quantum Monte Carlo simulations utilizing an accurate pair potential and a modified trial wavefunction which allows for anisotropy. Near the melting density, we find no anisotropy in an ideal hcp 4He crystal. A theoretical equation of state is derived from the calculated energies of the ideal crystal over a range of molar volumes from 7.88 to 21.3 cm3, and is found to be in good qualitative agreement with experimental data.

  16. Search for anisotropy in the Debye-Waller factor of HCP solid (4)He.

    PubMed

    Barnes, Ashleigh L; Hinde, Robert J

    2016-02-28

    The properties of hexagonal close packed (hcp) solid (4)He are dominated by large atomic zero point motions. An accurate description of these motions is therefore necessary in order to accurately calculate the properties of the system, such as the Debye-Waller (DW) factors. A recent neutron scattering experiment reported significant anisotropy in the in-plane and out-of-plane DW factors for hcp solid (4)He at low temperatures, where thermal effects are negligible and only zero-point motions are expected to contribute. By contrast, no such anisotropy was observed either in earlier experiments or in path integral Monte Carlo (PIMC) simulations of solid hcp (4)He. However, the earlier experiments and the PIMC simulations were both carried out at higher temperatures where thermal effects could be substantial. We seek to understand the cause of this discrepancy through variational quantum Monte Carlo simulations utilizing an accurate pair potential and a modified trial wavefunction which allows for anisotropy. Near the melting density, we find no anisotropy in an ideal hcp (4)He crystal. A theoretical equation of state is derived from the calculated energies of the ideal crystal over a range of molar volumes from 7.88 to 21.3 cm(3), and is found to be in good qualitative agreement with experimental data. PMID:26931710

  17. Detection of the YORP Effect for Small Asteroids in the Karin Cluster

    NASA Astrophysics Data System (ADS)

    Carruba, V.; Nesvorný, D.; Vokrouhlický, D.

    2016-06-01

    The Karin cluster is a young asteroid family thought to have formed only ≃ 5.75 Myr ago. The young age can be demonstrated by numerically integrating the orbits of Karin cluster members backward in time and showing the convergence of the perihelion and nodal longitudes (as well as other orbital elements). Previous work has pointed out that the convergence is not ideal if the backward integration only accounts for the gravitational perturbations from the solar system planets. It improves when the thermal radiation force known as the Yarkovsky effect is accounted for. This argument can be used to estimate the spin obliquities of the Karin cluster members. Here we take advantage of the fast growing membership of the Karin cluster and show that the obliquity distribution of diameter D≃ 1{--}2 km Karin asteroids is bimodal, as expected if the YORP effect acted to move obliquities toward extreme values (0° or 180°). The measured magnitude of the effect is consistent with the standard YORP model. The surface thermal conductivity is inferred to be 0.07–0.2 W m‑1 K‑1 (thermal inertia ≃ 300{--}500 J m‑2 K‑1 s{}-1/2). We find that the strength of the YORP effect is roughly ≃ 0.7 of the nominal strength obtained for a collection of random Gaussian spheroids. These results are consistent with a surface composed of rough, rocky regolith. The obliquity values predicted here for 480 members of the Karin cluster can be validated by the light-curve inversion method.

  18. Elastic properties of collagen in bone determined by measuring the Debye-Waller factor.

    PubMed

    Sasaki, Naoki; Shirakawa, Hideki; Nozoe, Tsutomu; Furusawa, Kazuya

    2013-11-15

    Force constant values for thermal vibrational motion of a collagen molecule along the helix axis in tendon, completely demineralized bone (CDB), and partially demineralized bone (PDB) were estimated by determining the Debye-Waller factor (DW factor) for the diffracted X-ray intensity from these specimens. The DW factor for nominal value of 0.286nm meridional diffraction representing a period along the helical axis of a collagen molecule was measured. As the atomic scattering factor of mineral constituents is much larger than that of collagen, it is difficult to detect the diffraction from collagen in bone specimen. Therefore, PDB was used in this study. In order to compare obtained force constant value for CDB with mechanical properties of collagen in the literature, the value was translated into Young's modulus value using the cross-sectional area of a collagen molecule. In the case of collagen in PDB, i.e., collagen with the close presence of HAp mineral particles, as the DW factor of the diffracted intensity by hydroxyapatite (HAp) was considered to be negligible compared with that of collagen, the DW factor determined was interpreted as that of collagen molecule in PDB specimen. The force constant value obtained for collagen in PDB was significantly larger than that of collagen in CDB. This result was thought to be a manifestation of the hardening of collagen matrix in bone by HAp mineral particles and the first straightforward evidence for a difference in collagen properties depending on the presence of HAp mineral particles. The method employed in this study can be utilized for detecting mechanical properties of the individual constituents of composite materials. PMID:24090493

  19. Monte Carlo Simulation Using Johnson Potential on Gd-Mg Alloy for Debye-Waller Factor and Debye Temperature

    NASA Astrophysics Data System (ADS)

    Chitra, S.; Ramachandran, K.

    Monte Carlo simulation (MCS) on the thermal properties in Gd-Mg alloy becomes essential as there are only limited experiments available. A realistic Johnson potential is used to workout the specific heats for various temperatures and hence the Debye temperature. The results from the present simulation technique are very well compared with our shell model calculation. The need of better X-ray measurements for Debye-Waller factor and Debye temperature other than the measurements of Subadhra and Sirdeshmukh, is discussed in detail.

  20. Difference in Degree of Space Weathering on the Newborn Asteroid Karin

    NASA Astrophysics Data System (ADS)

    Sasaki, T.; Sasaki, S.; Watanabe, J. I.; Sekiguchi, T.; Yoshida, F.; Ito, T.; Kawakita, H.; Fuse, T.; Takato, N.; Dermawan, B.

    2005-03-01

    Here we report a near-infrared spectroscopy of the newborn asteroid Karin. For different rotational phases, we derived different spectra such as reddened spectrum like that of S- type asteroid and un-reddened spectrum like that of ordinary chondrite.

  1. Details of Recent Collisions of Asteroids 832 Karin and 158 Koronis

    NASA Astrophysics Data System (ADS)

    Molnar, Lawrence A.; Haegert, M. J.

    2009-09-01

    We present analysis of the membership and dynamics of two recently formed asteroid clusters: 832 Karin (5.72 My) and 158 Koronis (15.0 My). The unprecedented detail of both collisions (one catastrophic and one not) provides rigorous tests of asteroid collision models. We use the AstDyS catalog of analytic proper elements to identify asteroids with high quality orbits that are dynamically near the Karin cluster (873 objects), and use the OrbFit software to compute precise synthetic proper elements. We define a cut in five dimensional phase space to determine Karin membership. The key to an effective cut is the use of two linear combinations of elements: a combination of the longitudes that is independent of the Yarkovsky drift and a combination of eccentricity and drift-corrected semimajor axis. Karin cluster membership is increased to 387 objects, four times the previously published number. Highlights of analysis include a size-frequency distribution with significant curvature, and two clusters in the histogram of spin obliquities (inferred from the Yarkovsky drift of the longitudes). The latter is consistent with capture of the smallest members (diameters less than 2 km) in Slivan states. Removal of the Karin members from the sample reveals a previously unknown cluster of 151 objects resulting from a recent non-catastrophic collision with Koronis (which has 98.7% of the total mass). With an age of 15 My, individual longitudes have drifted by as much as 540 degrees due to the Yarkovsky effect, yet it remains possible to unwrap the angles and determine membership. Highlights of the analysis include final speeds relative to Koronis less than the escape speed and a pronounced preference for outflow directions in a small cone. The mass of the material launched below escape speed likely exceeds that of the escaped objects. Funded by a Kuiper endowment and a Calvin Research Fellowship.

  2. A survey of Karin cluster asteroids with the Spitzer Space Telescope

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Mueller, Michael; Lisse, Carey M.; Cheng, Andrew F.

    2009-01-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8±0.2 Myr ago. Using the Spitzer Space Telescope we have photometrically sampled the thermal continua (3.5-22 μm) of 17 Karin cluster asteroids of different sizes, down to the smallest members discovered so far, in order to make the first direct measurements of their sizes and albedos and study the physical properties of their surfaces. Our targets are also amongst the smallest main-belt asteroids observed to date in the mid-infrared. The derived diameters range from 17.3 km for 832 Karin to 1.5 km for 75176, with typical uncertainties of 10%. The mean albedo is p=0.215±0.015, compared to 0.20±0.07 for 832 Karin itself (for H=11.2±0.3), consistent with the view that the Karin asteroids are closely related physically as well as dynamically. The albedo distribution ( 0.12⩽p⩽0.32) is consistent with the range associated with S-type asteroids but the variation from one object to another appears to be significant. Contrary to the case for near-Earth asteroids, our data show no evidence of an albedo dependence on size. However, the mean albedo is lower than expected for young, fresh "S-type" surfaces, suggesting that space weathering can darken main-belt asteroid surfaces on very short timescales. Our data are also suggestive of a connection between surface roughness and albedo, which may reflect rejuvenation of weathered surfaces by impact gardening. While the available data allow only estimates of lower limits for thermal inertia, we find no evidence for the relatively high values of thermal inertia reported for some similarly sized near-Earth asteroids. Our results constitute the first observational confirmation of the legitimacy of assumptions made in recent modeling of the formation of the Karin cluster via a single catastrophic collision 5.8±0.2 Myr ago.

  3. Temperature dependence of the lattice parameter and Debye-Waller factor of a high-chromium pressure-vessel steel

    NASA Astrophysics Data System (ADS)

    Sumin, V. V.; Simkin, V. G.; Sheverev, S. G.; Leont'eva-Smirnova, M. V.; Chernov, V. M.

    2009-12-01

    The method of thermal neutron diffraction has been used to study samples of the EK-181 steel at temperatures of 15 to 973 K in an IBR-2 reactor (Joint Institute for Nuclear Research (JINR)). Temperature dependences of the lattice parameter, internal textural stresses (of the third kind), and the Debye-Waller factor of this steel have been calculated from diffraction spectra by the Rietveld method. It has been found that at low temperatures the temperature dependence of the lattice parameter in the EK-181 steel (RUSFER EK-181) differs from the corresponding dependence in pure iron and binary iron-chromium alloys containing 12 and 16% Cr. Also, a broadening of the ( 200) reflection has been observed in the diffraction spectra of the EK-181 steel and the Fe-12Cr alloy, while it is not detected in the spectra of Fe-16Cr and pure iron.

  4. Testing the Deployment Repeatability of a Precision Deployable Boom Prototype for the Proposed SWOT Karin Instrument

    NASA Technical Reports Server (NTRS)

    Agnes, Gregory S.; Waldman, Jeff; Hughes, Richard; Peterson, Lee D.

    2015-01-01

    NASA's proposed Surface Water Ocean Topography (SWOT) mission, scheduled to launch in 2020, would provide critical information about Earth's oceans, ocean circulation, fresh water storage, and river discharge. The mission concept calls for a dual-antenna Ka-band radar interferometer instrument, known as KaRIn, that would map the height of water globally along two 50 km wide swaths. The KaRIn antennas, which would be separated by 10 meters on either side of the spacecraft, would need to be precisely deployable in order to meet demanding pointing requirements. Consequently, an effort was undertaken to design build and prototype a precision deployable Mast for the KaRIn instrument. Each mast was 4.5-m long with a required dilitation stability of 2.5 microns over 3 minutes. It required a minimum first mode of 7 Hz. Deployment repeatability was less than +/- 7 arcsec in all three rotation directions. Overall mass could not exceed 41.5 Kg including any actuators and thermal blanketing. This set of requirements meant the boom had to be three times lighter and two orders of magnitude more precise than the existing state of the art for deployable booms.

  5. Polarimetric evidence of close similarity between members of the Karin and Koronis dynamical families

    NASA Astrophysics Data System (ADS)

    Cellino, A.; Delbò, M.; Bendjoya, Ph.; Tedesco, E. F.

    2010-10-01

    We present the results of a campaign of polarimetric observations of small asteroids belonging to the Karin and Koronis families, carried out at the ESO Cerro Paranal Observatory using the VLT-Kueyen 8-m telescope. The Karin family is known to be very young, having likely been produced by the disruption of an original member of the Koronis family less than 6 Myr ago. The purpose of our study was to derive polarimetric properties for a reasonable sample of objects belonging to the two families, in order to look for possible systematic differences between them, to be interpreted in terms of differences in surface properties, in particular albedo. In turn, systematic albedo differences might be caused by different times of exposure to space weathering processes experienced by the two groups of objects. The results of our analysis indicate that no appreciable difference exists between the polarimetric properties of Karin and Koronis members. We thus find that space-weathering mechanisms may be very efficient in affecting surface properties of S-class asteroids on very short timescales. This result complements some independent evidence found by recent spectroscopic studies of very young families.

  6. Atomic disorder of Li0.5Ni0.5O thin films caused by Li doping: estimation from X-ray Debye–Waller factors

    PubMed Central

    Yang, Anli; Sakata, Osami; Yamauchi, Ryosuke; Kumara, L. S. R.; Song, Chulho; Katsuya, Yoshio; Matsuda, Akifumi; Yoshimoto, Mamoru

    2015-01-01

    Cubic type room-temperature (RT) epitaxial Li0.5Ni0.5O and NiO thin films with [111] orientation grown on ultra-smooth sapphire (0001) substrates were examined using synchrotron-based thin-film X-ray diffraction. The 11 and 22 rocking curves including six respective equivalent reflections of the Li0.5Ni0.5O and NiO thin films were recorded. The RT B 1 factor, which appears in the Debye–Waller factor, of a cubic Li0.5Ni0.5O thin film was estimated to be 1.8 (4) Å2 from its 11 and 22 reflections, even though the Debye model was originally derived on the basis of one cubic element. The corresponding Debye temperature is 281 (39) K. Furthermore, the B 2 factor in the pseudo-Debye–Waller factor is proposed. This parameter, which is evaluated using one reflection, was also determined for the Li0.5Ni0.5O thin film by treating Li0.5Ni0.5O and NiO as ideal NaCl crystal structures. A structural parameter for the atomic disorder is introduced and evaluated. This parameter includes the combined effects of thermal vibration, interstitial atoms and defects caused by Li doping using the two Debye–Waller factors. PMID:26664345

  7. Effect of Particle Size and Lattice Strain on the Debye-Waller Factors of Silicon Carbide Nanoparticles.

    PubMed

    Purushotham, E

    2016-03-01

    Nano Silicon Carbide (SiC) particles have been produced by ball milling process. The sample was taken 0, 10, 20, 30, 40 and 50 hours of milling. The resulting nanoparticle powders were characterized by X-ray diffraction measurements. The high-energy ball milling of SiC after 50 hours resulted in particle size of about 24 nm. The Debye temperature, mean-square amplitudes of vibration, Debye-Waller factor, particle size, and lattice strain and vacancy formation of energies of SiC nanoparticles prepared by ball mill have been obtained from X-ray integrated intensities. The integrated intensities have been measured with a Philips CWU 3710 X-ray powder diffractometer fitted with a scintillation counter using filtered CuKα radiation at room temperature and have been corrected for thermal diffuse scattering. The X-ray Debye temperatures obtained in the present investigation has been used to estimate the vacancy formation energies for SiC nanoparticles. PMID:27455685

  8. Modeling asteroid surfaces from observations and irradiation experiments: The case of 832 Karin

    NASA Astrophysics Data System (ADS)

    Brunetto, Rosario; Vernazza, Pierre; Marchi, Simone; Birlan, Mirel; Fulchignoni, Marcello; Orofino, Vincenzo; Strazzulla, Giovanni

    2006-10-01

    We define a new approach to model asteroidal space weathering. We started from recent results of ion irradiation experiments (60-400 keV) of meteorites and silicates to give an accurate description of space weathering, and we included its effects in the Shkuratov model. We found that the reddening and darkening process (in the range 0.3-2.5 μm) does not significantly affect the position or relative intensities of the mafic silicate absorption features and it mainly affects the continuum of reflectance spectra. This continuum is parameterized by a C coefficient, which is strongly related with the number of displacements per unit area (damage parameter); we consequently obtained an exposure time curve, and corresponding astrophysical timescales. We applied this new description of space weathering to model observed spectra of Asteroid 832 Karin, in the 0.4-2.4 μm spectral region. The obtained exposure time is slightly lower than the age of the impact and collisional breakup which originated the Karin asteroidal family, i.e., about 5.75×10 years.

  9. A spectral model for irradiated silicates: application to asteroid 832 Karin

    NASA Astrophysics Data System (ADS)

    Brunetto, R.; Vernazza, P.; Marchi, S.; Birlan, M.; Fulchignoni, M.; Orofino, V.; Strazzulla, G.

    We define a new approach to space weathering of airless bodies, and include its effect in the Shkuratov model. We start from recent results of ion irradiation experiments (60-400 keV) of meteorites and silicates; we find that the reddening and darkening process (in the range 0.3-2.5 microns) mainly affects the continuum of reflectance spectra (parameterized by a Cs coefficient), but it does not significantly affect the position or relative intensities of the mafic silicate absorption features. The Cs coefficient is strongly related with the number of displacements per unit area (damage parameter); we consequently obtain an exposure time curve, and corresponding astrophysical timescales. We apply this new description of space weathering to model observed spectra of asteroid 832 Karin, in the 0.4-2.4 microns spectral region. The obtained exposure time is slightly lower than the age of the impact and collisional breakup which originated the Karin asteroidal family, i.e. about 5.75 My.

  10. Self-Consistent Interpretation of the 2D Structure of the Liquid Au82Si18 Surface: Bending Rigidity and the Debye-Waller Effect

    NASA Astrophysics Data System (ADS)

    Mechler, S.; Pershan, P. S.; Yahel, E.; Stoltz, S. E.; Shpyrko, O. G.; Lin, B.; Meron, M.; Sellner, S.

    2010-10-01

    The structural and mechanical properties of 2D crystalline surface phases that form at the surface of liquid eutectic Au82Si18 are studied using synchrotron x-ray scattering over a large temperature range. In the vicinity of the eutectic temperature the surface consists of a 2D atomic bilayer crystalline phase that transforms into a 2D monolayer crystalline phase during heating. The latter phase eventually melts into a liquidlike surface on further heating. We demonstrate that the short wavelength capillary wave fluctuations are suppressed due to the bending rigidity of 2D crystalline phases. The corresponding reduction in the Debye-Waller factor allows for measured reflectivity to be explained in terms of an electron density profile that is consistent with the 2D surface crystals.

  11. Onboard Interferometric SAR Processor for the Ka-Band Radar Interferometer (KaRIn)

    NASA Technical Reports Server (NTRS)

    Esteban-Fernandez, Daniel; Rodriquez, Ernesto; Peral, Eva; Clark, Duane I.; Wu, Xiaoqing

    2011-01-01

    An interferometric synthetic aperture radar (SAR) onboard processor concept and algorithm has been developed for the Ka-band radar interferometer (KaRIn) instrument on the Surface and Ocean Topography (SWOT) mission. This is a mission- critical subsystem that will perform interferometric SAR processing and multi-look averaging over the oceans to decrease the data rate by three orders of magnitude, and therefore enable the downlink of the radar data to the ground. The onboard processor performs demodulation, range compression, coregistration, and re-sampling, and forms nine azimuth squinted beams. For each of them, an interferogram is generated, including common-band spectral filtering to improve correlation, followed by averaging to the final 1 1-km ground resolution pixel. The onboard processor has been prototyped on a custom FPGA-based cPCI board, which will be part of the radar s digital subsystem. The level of complexity of this technology, dictated by the implementation of interferometric SAR processing at high resolution, the extremely tight level of accuracy required, and its implementation on FPGAs are unprecedented at the time of this reporting for an onboard processor for flight applications.

  12. KaRIn on SWOT: modeling and simulation of near-nadir Ka-band interferometric SAR images

    NASA Astrophysics Data System (ADS)

    Fjørtoft, Roger; Koudogbo, Fifamè; Duro, Javier; Ruiz, Christian; Gaudin, Jean-Marc; Mallet, Alain; Pourthie, Nadine; Lion, Christine; Ordoqui, Patrick; Arnaud, Alain

    2010-10-01

    The principal instrument of the wide-swath altimetry mission SWOT is KaRIn, a Ka-band interferometric SAR system operating on near-nadir swaths on both sides of the satellite track. Due to the short wavelength and particular observation geometry, there are very limited reports on the backscattering from natural surfaces. Simulators that cover both radiometric and geometric aspects are therefore developed in the framework of the CNES phase 0 and A studies of SWOT. This article presents the modeling and simulation approaches that have been adopted, and shows some preliminary simulation results.

  13. Wrongful death claims. Harriton v Stephens. [2002] NSWSC 461. Edwards v Blomeley. [2002] NSWSC 460. Waller v James [2002] NSWSC 462.

    PubMed

    Devereux, John

    2002-11-01

    Studdert J in all three cases went to great length to summarise the global judicial position of "wrongful life" claims. He did not, however, examine in great length how or whether "wrongful life" claims or "wrongful birth" claims are reconcilable with tort and common law principles. Although the cases identify the difficulty in assessing and quantifying damages, they do not directly address the strict legal principles which apply in the assessment of damages. The main conclusion of the three judgments was that no duty of care is owed to the plaintiff in these circumstances and, even if a duty could be established, the impossibility of quantifying damages and public policy considerations warrant the rejection of such a claim: "thus conscience does make cowards of us all." The significance of the decisions cannot be understand. The decisions deny recognition of "wrongful life" claims in circumstances where a disabled person has incurred injuries en ventre sa mere (in the mother's womb) as a result of infections contracted by a plaintiff's mother or genetic material passed on by a plaintiff's parents. Some countries have now legislated for the abolition of "wrongful life and birth" suits. In January 2002 the French legislature passed a Bill overturning the "wrongful life" decision of the Cour de Cassation in Perruche (17 November 2000). As the issue now falls for ultimate determination by the French Senate, the French pro-life movement continues to lobby for the prohibition of "wrongful birth" suits as well. Furthermore, eight States in the United States have prohibited either one or both actions and the State of Michigan prohibited both actions in 2001. It is likely that all three cases will be appealed. The appeal in Harriton will re-examine the viability of a "wrongful life" claim in Australia whereas the cases of Edwards and Waller still need to determine the "wrongful birth" claims brought by the plaintiffs' parents. It is likely that the latter two cases will

  14. An alternative explanation of the change in T-dependence of the effective Debye-Waller factor at Tc or TB

    NASA Astrophysics Data System (ADS)

    Ngai, K. L.; Habasaki, J.

    2014-09-01

    The cusp-like temperature dependence of the Debye-Waller factor or non-ergodicity parameter fQ(T) at some temperature Tc above Tg found by experiments in several fragile glassformers has been considered as critical evidence for validity of the ideal Mode Coupling Theory (MCT). A comprehensive review of experimental data of fQ(T) and beyond brings out various problems of the MCT predictions. For example, the molten salt, 0.4Ca(NO3)2-0.6KNO3 (CKN), was the first glassformer measured by neutron scattering to verify the cusp-like behavior of fQ(T) at Tc predicted by ideal MCT. While the fits of the other scaling laws of MCT to viscosity, light scattering, and dielectric relaxation data all give Tc in the range from 368 to 375 K, there is no evidence of cusp-like behavior of fQ(T) at Tc from more accurate neutron scattering data obtained later on by Mezei and Russina [J. Phys.: Condens. Matter 11, A341 (1999)] at temperatures below 400 K. In several molecular glass-formers, experiments have found at temperatures below Tc that [1-fQ(T)] is manifested as nearly constant loss (NCL) in the frequency dependent susceptibility. The NCL persists down to below Tg and is not predicted by the ideal MCT. No clear evidence of the change of T-dependence of fQ(T) at any Tc was found in intermediate and strong glassformers, although ideal MCT does not distinguish fragile and strong glassformers in predicting the critical behavior of fQ(T) a priori. Experiments found fQ(T) changes T-dependence not only at Tc but also at the glass transition temperature Tg. The changes of T-dependence of fQ(T) at Tc and Tg are accompanied by corresponding changes of dynamic variables and thermodynamic quantities at TB ≈ Tc and at Tg. The dynamic variables include the relaxation time τα(T), the non-exponentiality parameter n(T), and the generalized fragility m(T) of the structural α-relaxation. The thermodynamic quantities are the free volume deduced from positron annihilation spectroscopy, and the

  15. An alternative explanation of the change in T-dependence of the effective Debye-Waller factor at T{sub c} or T{sub B}

    SciTech Connect

    Ngai, K. L.; Habasaki, J.

    2014-09-21

    The cusp-like temperature dependence of the Debye-Waller factor or non-ergodicity parameter f{sub Q}(T) at some temperature T{sub c} above T{sub g} found by experiments in several fragile glassformers has been considered as critical evidence for validity of the ideal Mode Coupling Theory (MCT). A comprehensive review of experimental data of f{sub Q}(T) and beyond brings out various problems of the MCT predictions. For example, the molten salt, 0.4Ca(NO{sub 3}){sub 2}-0.6KNO{sub 3} (CKN), was the first glassformer measured by neutron scattering to verify the cusp-like behavior of f{sub Q}(T) at T{sub c} predicted by ideal MCT. While the fits of the other scaling laws of MCT to viscosity, light scattering, and dielectric relaxation data all give T{sub c} in the range from 368 to 375 K, there is no evidence of cusp-like behavior of f{sub Q}(T) at T{sub c} from more accurate neutron scattering data obtained later on by Mezei and Russina [J. Phys.: Condens. Matter 11, A341 (1999)] at temperatures below 400 K. In several molecular glass-formers, experiments have found at temperatures below T{sub c} that [1−f{sub Q}(T)] is manifested as nearly constant loss (NCL) in the frequency dependent susceptibility. The NCL persists down to below T{sub g} and is not predicted by the ideal MCT. No clear evidence of the change of T-dependence of f{sub Q}(T) at any T{sub c} was found in intermediate and strong glassformers, although ideal MCT does not distinguish fragile and strong glassformers in predicting the critical behavior of f{sub Q}(T) a priori. Experiments found f{sub Q}(T) changes T-dependence not only at T{sub c} but also at the glass transition temperature T{sub g}. The changes of T-dependence of f{sub Q}(T) at T{sub c} and T{sub g} are accompanied by corresponding changes of dynamic variables and thermodynamic quantities at T{sub B} ≈ T{sub c} and at T{sub g}. The dynamic variables include the relaxation time τ{sub α}(T), the non-exponentiality parameter n(T), and

  16. KaRIN: an Instrument for Measuring High-Resolution Sea-Surface Topography and Fresh Water Extent, Stage, and Slope

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Moller, D.; Enjolras, V.

    2006-12-01

    Traditional nadir profiling altimeters, such as Topex, Jason, or IceSat, are incaple of fully sampling the space- time signatures of both ocean mesoscale and submesoscale phenomena and changes in river discharge. To overcome this limitation, we present an instrument concept, the Ka-band Radar Interferometer (KaRIN), which is able to provide the appropriate space-time sampling to sample these phenomena with a height and slope accuracy suitable to resolve topographic signatures for both ocean and land hydrology applications. Although ocean and hydrlogic applications are quite different, the required sampling characteristics are similar. Both applications require global coverage up to high latitudes (78deg). Measurement of ocean mesoscale and submesoscale phenomena requires a temporal revisit time on the order of 10 days and a height accuracy of about 2cm over a spatial scale of 2km. The sampling of river discharge requires an approximately weekly revisit time, an ability to image water bodies (to determine extent) with a spatial resolution of 100m, a height accuracy better than 10cm and a slope accuracy of 1cm/1km, after averaging over a river area equivalent to 1km x 1km. The similarity in measurement requirements allows for the possibility of meeting both ocean and hydrology requirements with a single instrument. The KaRIN instrument builds on the interferometric SAR concept demonstrated by the NASA Shuttle Radar Topography Mission (SRTM), and the Wide-Swath Ocean Altimeter concept, which was studied by NASA as a potential complement to the Ocean Surface Topography Mission (OSTM). Two major modifications are made to these systems to achieve the desired performance: the spatial sampling requirement implies that full synthetic aperture must be used. Second, achieving the desired height and slope accuracy with a realizable spaceborne instrument requires using a Ka-band (0.8 cm wavelength) radar at near nadir incidence. To validate the science performance of the

  17. Debye-Waller factor in solid He-4 at sub-Kelvin temperatures

    NASA Astrophysics Data System (ADS)

    Blackburn, Elizabeth; Goodkind, John M.; Sinha, Sunil K.; Hudis, Jacob; Broholm, Collin; van Duijn, Joost; Down, Richard; Kirichek, Oleg; Frost, Chris D.

    2007-03-01

    The recent observation by Kim and Chan [Science 305 (2204) 1941] of a transition at low temperatures (˜ 200 mK) in the hcp-phase of solid helium has re-opened interest in the old question of supersolidity. The nature of the low-temperature phase remains in question, and to investigate this in more detail, we have measured the density distribution of He-4 nuclei in crystals of He-4 with a molar volume of 21.3 cm^3 down to 140 mK. We find no evidence for any changes in the vicinity of the transition. Treating the material as a traditional crystal, we have extracted the mean square displacement for the nuclei and find anisotropy between the in- and out-of-plane motions. Our values are in agreement with previous work at higher temperatures.

  18. I.H. HALL, S.D. WYRICK, C.L. WALLER

    EPA Science Inventory

    Substituted oxoisoindolines are effective cytotoxic agents, causing cell death in a number of tissue culture lines, e.g. L1210, Tmolt-3, and HeLa-S3. n general these agents were not active against the solid cell growth, i.e. KB, skin, HCT-8 ileum, colon, bronchogenic lung, osteos...

  19. The social nature of disability, disease and genetics: a response to Gillam, Persson, Holtug, Draper and Chadwick.

    PubMed Central

    Newell, C

    1999-01-01

    The dominance of the biomedically informed view of disability, genetics, and diagnosis is explored. An understanding of the social nature of disability and genetics, especially in terms of oppression, adds a richer dimension to an understanding of ethical issues pertaining to genetics. This is much wider than the limited question of whether or not such technology discriminates. Instead, it is proposed that such technology will perpetuate the oppression and control of people with disability, especially if the knowledge of people with disability is not utilised in bioethical debates. PMID:10226924

  20. Response to commentaries by Karin Rolanda Jongsma and Suzanne van de Vathorst, and Oliver Hallich.

    PubMed

    Buller, Thomas

    2015-08-01

    The authors of the two commentaries raise some interesting and important objections to my paper, 'Advance Consent, Critical Interests, and Dementia Research'. In my response I try to show that the objections raised can be understood as general objections against advance directives, rather than against research directives in particular. Since my main argument in the paper is that if we accept advance directives for treatment then we should accept them for research, arguments showing that we should not accept advance directives at all are consistent with my point of view. PMID:25887513

  1. 75 FR 76482 - Federal Housing Administration (FHA): FHA Maximum Loan Limits for 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-08

    .../ . FOR FURTHER INFORMATION CONTACT: Karin B. Hill, Director, Office of Single Family Program Development.../. Dated: November 29, 2010. Karin Hill, Director, Office of Single Family Program Development....

  2. KARIN: The Ka-Band Radar Interferometer for the Proposed Surface Water and Ocean Topography (SWOT) Mission

    NASA Technical Reports Server (NTRS)

    Esteban-Fernandez, Daniel; Peral, Eva; McWatters, Dalia; Pollard, Brian; Rodriguez, Ernesto; Hughes, Richard

    2013-01-01

    Over the last two decades, several nadir profiling radar altimeters have provided our first global look at the ocean basin-scale circulation and the ocean mesoscale at wavelengths longer than 100 km. Due to sampling limitations, nadir altimetry is unable to resolve the small wavelength ocean mesoscale and sub-mesoscale that are responsible for the vertical mixing of ocean heat and gases and the dissipation of kinetic energy from large to small scales. The proposed Surface Water and Ocean Topography (SWOT) mission would be a partnership between NASA, CNES (Centre National d'Etudes Spaciales) and the Canadian Space Agency, and would have as one of its main goals the measurement of ocean topography with kilometer-scale spatial resolution and centimeter scale accuracy. In this paper, we provide an overview of all ocean error sources that would contribute to the SWOT mission.

  3. Antipsychotics Don't Ease Delirium in Hospitalized Patients

    MedlinePlus

    ... a patient with delirium," said lead researcher Dr. Karin Neufeld, clinical director of psychiatry at Johns Hopkins ... obvious, but they are important," he added. SOURCES: Karin Neufeld, M.D., M.P.H., clinical director, ...

  4. 75 FR 40819 - Reliability Standards Development and NERC and Regional Entity Enforcement; Notice Soliciting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-14

    ... Technical Conference, 75 FR 36,385 (June 18, 2010). Anyone with questions pertaining to the technical conference or this notice should contact either Karin Larson at 202-502-8236, Karin.Larson@ferc.gov...

  5. 75 FR 3240 - Center for Scientific Review; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-20

    ...: Karin F. Helmers, PhD, Scientific Review Officer, Center for Scientific Review, National Institutes of... Institutes of Health, 6701 Rockledge Drive, Bethesda, MD 20892, (Virtual Meeting.) Contact Person: Karin...

  6. The Debate on Dominant Culture and Cultural Imperialism

    ERIC Educational Resources Information Center

    Anchan, John P.

    2012-01-01

    In this commentary, the author reviews in depth Roland S. Persson's (2012a) target article. According to him Persson (2012a) presents a convincing argument as he wove through examples and explanations. The idea of superculture connects well with the established neocolonial literature and the North-South/Centre-Periphery debate. From general to…

  7. A Catalyst for Charting a Path to Research Validity in the Field of Gifted Education

    ERIC Educational Resources Information Center

    Sisk, Dorothy A.

    2012-01-01

    Roland S. Persson's (2012a) article addresses a concern that many educators have stressed in their theoretical models, namely the importance of the interaction between the individual and the environment, and the impact of culture on not only values and beliefs, but on behaviour. As Persson (2012a) points out these models all have merit, but he…

  8. The Surface Water and Ocean Topography Mission (SWOT): the Ka-band Radar Interferometer (KaRIn) for water level measurements at all scales

    NASA Astrophysics Data System (ADS)

    Rodriguez, Ernesto; Esteban-Fernandez, Daniel

    2010-10-01

    The Surface Water and Ocean Topography (SWOT) mission will study ocean mesoscale and submesoscale phenomena and provide an inventory of storage change and discharge for fresh water bodies and rivers. In this paper, we examine the combination of measurements that will be used by SWOT to achieve a globally consistent data set. We introduce a new channel in the SWOT measurement that combines data transmitted by the interferometer antennas and received by the radiometer antenna allows the closing of the SWOT nadir coverage gap. This new mode also allows for improved calibration between the nadir altimeter and the interferometer, resulting in consistent range measurements. Consistency in the phase measurements is achieved using a mixture of cross-over calibration combined with optimal estimation of system error drift.

  9. Bonding study of TiC and TiN. I. High-precision x-ray-diffraction determination of the valence-electron density distribution, Debye-Waller temperature factors, and atomic static displacements in TiC0.94 and TiN0.99

    NASA Astrophysics Data System (ADS)

    Dunand, A.; Flack, H. D.; Yvon, K.

    1985-02-01

    Single-crystal, high-precision, high-resolution x-ray-diffraction measurements of the substoichiometric refractory compounds TiC and TiN have been performed with AgKα radiation. Severe anisotropic general extinction affects the intense low-order reflections. Inhomogeneity in the mosaic spread and domain size produces small but significant differences between reflection and antireflection for the same plane of diffraction. These effects have been modeled and refined together with a scale factor, isotropic thermal parameters, a population parameter of the nonmetal site, the amplitude of metal-atom static displacements around nonmetal vacancies, and an atomic model which includes occupancy factors of the separate orbital contributions of the valence electrons combined with κ expansion-contraction parameters. At convergence, the ``agreement indices'' (or ``reliability factors'') were R=0.0025 for TiC0.94 and R=0.0023 for TiN0.99. The refined population parameters indicate a chemical composition of TiC0.939(9) and TiN0.99(2). The mean-square amplitudes of thermal vibrations, Ti=0.002 38(2) AṦ, C=0.003 35(8) AṦ, Ti=0.002 94(1) AṦ, and N=0.003 08(12) AṦ are consistent with the respective atomic masses. 36% of the metal atoms in TiC0.94 are involved in a relaxation around the nonmetal vacancies, being displaced from their sublattice sites by 0.097(2) Å along [100]. No evidence for static displacements was found in TiN0.99. The valence-electron density distribution can be described satisfactorily in terms of deformed atoms. No buildup of charge density occurs between atomic sites. Our analysis, similar to a Mulliken partitioning, shows first that ionicity is important, with a charge transfer from the metal to the nonmetal of [2.1(4)]e in the carbide and [1.9(4)]e in the nitride, and secondly that the charge asphericity around the metal atoms is larger in the former than in the latter, while no departure from spherical symmetry is observed around the nonmetal atoms. The titanium 3d electrons can be split into a spherical shell that contains [1.27(6)]e plus an excess of [0.24(5)]e shared by two orbitals of eg symmetry in the carbide and conversely into a spherical shell that contains [0.88(11)]e plus an excess of [0.12(9)]e shared by three orbitals of t2g symmetry in the nitride. This suggests that the metal-to-metal bonding is similar in TiC and in TiN while the metal-to-nonmetal bonding is greater in TiC than in TiN.

  10. Reflectance Spectra of Members of Very Young Asteroid Families

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.; Enke, B.; Merline, W. J.; Nesvorný, D.; Tamblyn, P.; Young, E. F.

    2009-03-01

    We present SpeX infrared spectra for members of the dynamically young Datura, Iannini, Karin, and Veritas asteroid families (plus Koronis and Themis family controls). S-types are space-weathered on timescales of a few million years.

  11. 75 FR 35021 - Reliability Standards Development and NERC and Regional Entity Enforcement; Notice of Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-21

    ... conference may be directed to: Karin L. Larson, Office of the General Counsel--Energy Markets, Federal Energy Regulatory Commission, 888 First Street, NE., Washington, DC 20426, (202) 502-8236,...

  12. Photometric Observation of Young Asteroid Family in 2006-2010 at Maidanak Observatory, Uzbekistan

    NASA Astrophysics Data System (ADS)

    Yoshida, F.; Nozawa, Y.; Ito, T.; Takahashi, S.; Okita, K.; Ibrahimov, M.; Ehgamberdiev, S.; Marshalkina, A.; Karimov, R.; Burhonov, O.; Tillayev, Y.; Hafizov, B.; Yanagisawa, T.; Kurosaki, H.; Yoshikawa, M.; Urakawa, S.; Ohtani, H.

    2012-05-01

    We observed 43 young family asteroids (Karin, Iannini, Veritas) and 7 old family asteroids (Koronis, Themis) at Maidanak Observatory, then determined their rotation period, lightcurve amplitude, B-V, V-R, V-I colors.

  13. Research Needs in Business Education.

    ERIC Educational Resources Information Center

    D'Onofrio, Marianne J., Ed.; And Others

    1990-01-01

    Set of five articles includes "Introduction" (D'Onofrio); "Teaching Higher-Order Thinking Skills" (Maxam); "Research Questions in Teaching Software" (Franz, Waller); "Research in International Business Education" (Blockhus); and "The Knowledge Worker and Computer Technology" (Graf). (JOW)

  14. The Recognition of Cultural Bias in Researching Those Labelled Gifted: An Overdue Perspective

    ERIC Educational Resources Information Center

    Mazzoli Smith, L.; Campbell, R. J.

    2012-01-01

    This commentary addresses the analysis in Persson's (2012a) article. According to the authors, the agenda for change amongst scholars has four productive proposals. These are: (1) that scholars should broaden their disciplinary outlook beyond psychology and education; (2) that they should eschew policy borrowing; (3) that they should clarify, for…

  15. Basic Framework to Understand Identity Development in a Multicultural Context

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.; Valdez, Gilbert

    2012-01-01

    In the lead article, Persson (2012a) focuses on salient issues that have not as yet been addressed by others, and which are relevant, and germane. With the advent of the Internet and web and e-mail, conversation and discussion among scholars have increased tremendously. At the current time, researchers are able to share their data, their thoughts…

  16. Some Thoughts on "Cultural Variation and Dominance in a Globalised Knowledge-Economy"

    ERIC Educational Resources Information Center

    Yang, Yang; Gentry, Marcia

    2012-01-01

    To view giftedness research in a global context is an important and desirable attempt. Roland S. Persson (2012a), in the target article entitled Cultural Variation and Dominance in a Globalised Knowledge-Economy: Towards a Cultural-Sensitive Research Paradigm in the Science of Giftedness, delivers thought-provoking views in the cultural influences…

  17. IFLA General Conference, 1990. Division of Collections and Services: Section of Acquisition and Exchange; Section of Interlending and Document Delivery, Section of Serial Publications. Booklet 5.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    The 25 papers in this collection were presented at the meetings of three sections of the Division of Collections and Services and a workshop: (1) "Survey of International Exchange of Non-Official Publications: Progress Report" (Ulla Hojsgaard); (2) "Buying Media for Everyone: Public Library Acquisition in Scandinavia" (Tove Persson); (3) "The…

  18. On Universals, Cultural Variations and Individual Uniqueness: Throwing down the Gauntlet in Giftedness Research

    ERIC Educational Resources Information Center

    Garces-Bacsal, Rhoda Myra

    2012-01-01

    Roland S. Persson's (2012a) piece is extremely comprehensive, timely and very relevant especially in light of a growing appreciation of cultural diversity and the emergence of a global community--which is an inevitable offshoot of globalisation that goes beyond world economy and international markets. It covers multiple themes; ranging from…

  19. Critique of Cultural Variation and Dominance in a Globalised Knowledge-Economy: Towards a Culture-Sensitive Research Paradigm in the Science of Giftedness

    ERIC Educational Resources Information Center

    Harris, Carole Ruth

    2012-01-01

    Persson's (2012a) article is concerned with giftedness research in the light of cultural bias with a view to cultural dominance that derives from ethnocentricity. He questions the validity of current research that appears to ignore or sidestep cultural difference and proposes that an agenda for amelioration of such bias lies in greater awareness…

  20. In the Shadows of Dominant Cultures: The Elusive Definition of Giftedness

    ERIC Educational Resources Information Center

    Polyzoi, Eleoussa; Haydey, Donna Copsey

    2012-01-01

    In this commentary, the authors contend that Persson's (2012a) paper, Cultural Variation and Dominance in a Globalised Knowledge-Economy: Towards a Culture-Sensitive Research Paradigm in the Science of Giftedness, lacks conciseness in defining the connections between the significance of cultural dominance and the definition of giftedness. However,…

  1. The Scenic Route Is Not Always the Most Informative

    ERIC Educational Resources Information Center

    Freeman, Joan

    2012-01-01

    Roland S. Persson's (2012a) argument is that there is a dominant research culture in the field of gifts and talents, which must of necessity distort research and practice in cultures which are different. He ties this to the dominance of the global economy and points to the need for more cross-cultural studies. In this commentary, the author points…

  2. Probing Asteroid Families for Evidence of Ultraviolet Space Weathering Effects

    NASA Astrophysics Data System (ADS)

    Vilas, Faith

    2005-07-01

    We propose six HST orbits to obtain UV reflectance spectra covering 200-460 nm of two Vesta asteroid family members, asteroid 832 Karin, and two Karin family members. These observations extend work done under a Cycle 13 AR grant, where we analyzed all of the existing IUE and HST S-class asteroids in the MAST database to investigate the effects of space weathering at UV wavelengths. Our hypothesis is that the manifestation of space weathering at UV wavelengths is a spectral bluing, in contrast with a spectral reddening at visible-NIR wavelengths, and that UV wavelengths can be more sensitive to relatively small amounts of weathering than longer wavelengths. The proposed observations will address two objectives: {1} Measure the UV-visible spectra of 832 Karin and two members of the young Karin family {absolute age of 5.8 My}, in order to determine whether intermediate space weathering is observable in objects likely pristine when they originated from the interior of Karin's pa rent body. {2} Measure the UV-visible spectra of two members of the Vesta family to compare with our analysis of IUE Vesta spectra. These observations will probe Vesta's interior, and test our hypothesis by contrasting the apparent amount of alteration on the surfaces of Vestoids with excavated material on Vesta.

  3. The Misfortunes of Moral Enhancement.

    PubMed

    Azevedo, Marco Antonio

    2016-10-01

    In Unfit for the Future, Ingmar Persson and Julian Savulescu present a sophisticated argument in defense of the imperative of moral enhancement. They claim that without moral enhancement, the future of humanity is seriously compromised. The possibility of ultimate harm, caused by a dreadful terrorist attack or by a final unpreventable escalation of the present environmental crisis aggravated by the availability of cognitive enhancement, makes moral enhancement a top priority. It may be considered optimistic to think that our present moral capabilities can be successfully improved by means of moral education, moral persuasion, and fear of punishment. So, without moral enhancement, drastic restrictions on human freedom would become the only alternative to prevent those dramatic potential outcomes. In this article, I will try to show that we still have reason to be less pessimistic and that Persson & Savulescu's arguments are fortunately unconvincing. PMID:27473409

  4. Astronaut Eileen Collins is briefed on use of Sky Genie

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Eileen M. Collins, STS-63 mission pilot, is briefed on the use of Sky Genie device by Karin L. Porter. The device would aid in emergency egress operations aboard a troubled Space Shuttle. Porter, an employee of Rockwell International, helps train astronauts in egress procedures at JSC's Shuttle mockup and integration laboratory.

  5. The Role of Shared Knowledge in Science: The Failure of the Constructivist Programme in the Sociology of Science.

    ERIC Educational Resources Information Center

    Freudenthal, Gad

    1984-01-01

    Discusses various aspects of contructivism, focusing on the work of Karin Knorr-Cetina. Indicates that an internal critique of Knorr's arguments for the relativist program in the sociology highlights the role of shared knowledge in science and that Knorr's analysis produces new insights concerning the necessity and nature of scientific consensus.…

  6. Varia. Working Papers in Linguistics No. 47.

    ERIC Educational Resources Information Center

    Dowty, David, Ed.; And Others

    1995-01-01

    Papers in phonology, psycholinguistics, and syntax include: "Discriminating between Syntactic and Semantic Processing: Evidence from Event-Related Potentials" (Kim Ainsworth-Darnell); "The Syntactic Structure of Chinese Formal Focus" (Qian Gao); "Employing a Multimodal Logic in an Approach to German Pronoun Fronting" (Karin Golde); "The…

  7. Getting It Done: Leading Academic Success in Unexpected Schools

    ERIC Educational Resources Information Center

    Chenoweth, Karin; Theokas, Christina

    2011-01-01

    "Getting It Done" describes in clear and helpful detail what leaders of successful high-poverty and high-minority schools have done to promote and sustain student achievement. It follows two celebrated books by Karin Chenoweth: "It's Being Done," which established that the work of educating all children is possible, and "How It's Being Done,"…

  8. 75 FR 66038 - Planning Resource Adequacy Assessment Reliability Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-27

    ...-6652 or toll-free at 1-866-208-3676. FOR FURTHER INFORMATION CONTACT: Karin L. Larson (Legal Information), Office of the General Counsel, Federal Energy Regulatory Commission, 888 First Street, NE., Washington, DC 20426, (202) 502-8236. Scott Sells (Technical Information), Office of Electric...

  9. 78 FR 45541 - Center for Scientific Review ;Notice of Closed Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-29

    ... Committee: Center for Scientific Review Special Emphasis Panel; OppNet RFA: Culture, Health and Wellbeing... HUMAN SERVICES National Institutes of Health Center for Scientific Review ;Notice of Closed Meeting... Call). Contact Person: Karin F Helmers, Ph.D., Scientific Review Officer, Center for Scientific...

  10. Persistent Discourses in Physics Education: Gender Neutrality and the Gendering of Competence

    ERIC Educational Resources Information Center

    Gonsalves, Allison

    2014-01-01

    In her article, Karin Due presents us with a contradiction in physics: the construction of physics as a symbolically masculine discipline alongside a simultaneous discourse of the "gender-neutrality" of the discipline. Due's article makes an important contribution to the study of the gendering of physics practices, particularly in…

  11. Epistemic Practices and Object Relations in Professional Work

    ERIC Educational Resources Information Center

    Nerland, Monika; Jensen, Karen

    2012-01-01

    Professional practice is embedded in complex dynamics of knowledge that are present within, but reach beyond, local work. Knowledge is generated from a manifold of sources, and further developed and circulated in professional communities as practitioners are confronted with non-routine problems. Drawing on the work of Karin Knorr Cetina and her…

  12. 77 FR 39499 - Center For Scientific Review; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ... HUMAN SERVICES National Institutes of Health Center For Scientific Review; Notice of Closed Meetings... Committee: Center for Scientific Review Special Emphasis Panel Revisions on the Protections for Human...: Karin F. Helmers, Ph.D., Scientific Review Officer, Center for Scientific Review, National Institutes...

  13. Astronaut C. Michael Foale is briefed on use of Sky Genie

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut C. Michael Foale, STS-63 mission specialist, is briefed on the use of Sky Genie device by Karin L. Porter. The device would aid in emergency egress operations aboard a troubled Space Shuttle. Porter, an employee of Rockwell International, helps train astronauts in egress procedures at JSC's Shuttle mockup and integration laboratory.

  14. Astronaut James Wetherbee briefed on use of Sky Genie

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut James D. Wetherbee, STS-63 mission commander, is briefed on the use of Sky Genie device by Karin L. Porter. The device would aid in emergency egress operations aboard a troubled Space Shuttle. Porter, an employee of Rockwell International, helps train astronauts in egress procedures at JSC's Shuttle mockup and integration laboratory.

  15. Psycholinguistics and Foreign Language Learning. Papers from a Conference (Stockholm, Sweden and Abo, Finland, October 25-26, 1982). Meddelanden fran Stiftelsens for Abo Akademi Forskningsinstitut Nr.86.

    ERIC Educational Resources Information Center

    Ringbom, Hakan, Ed.

    At irregular intervals, beginning in 1977, Swedish-Finnish conferences on contrastive and applied linguistics have been arranged in Stockholm and Turko/Abo. This volume presents most of the papers given at the 1982 conference. Papers include: "Free Recall of Mixed Language Lists. Error Patterns in Bilingual Memory" (Karin Aronsson, Anja Metsola,…

  16. "Oya?"--O, Ja! Reading "Jugendliteratur" in the German Classroom.

    ERIC Educational Resources Information Center

    Moffit, Gisela

    1998-01-01

    Makes a plea for reading authentic "Jugendliteratur" in the foreign-language classroom. Focuses on the reasons for inclusions of this literature, discusses some of the reasons for its omission, and offers solutions to the problems perceived. Strategies for reading whole texts are shared and applied to the reading of "Oya" by Karin Konig, Hanne…

  17. How It's Being Done: Urgent Lessons from Unexpected Schools

    ERIC Educational Resources Information Center

    Chenoweth, Karin

    2009-01-01

    "How It's Being Done" offers much-needed help to educators, providing detailed accounts of the ways in which unexpected schools--those with high-poverty and high-minority student populations--have dramatically boosted student achievement and diminished (and often eliminated) achievement gaps. "How It"s Being Done" builds on Karin Chenoweth's…

  18. IMPROVING EXPOSURE ASSESSMENT IN DISINFECTION BYPRODUCTS (DBP) EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    In 1997, an EPA expert panel was convened to evaluate epidemiologic studies of adverse reproductive or developmental outcomes that may be associated with drinking water DBPs. The panel recommended that further efforts be made in an existing cohort study, headed by Dr. Waller and ...

  19. IMPROVING EXPOSURE ASSESSMENT IN DBP EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    In 1997, an EPA expert panel was convened to evaluate epidemiologic studies of adverse reproductive or developmental outcomes that may be associated with drinking water DBPs. The panel recommended that further efforts be made in an existing cohort study, headed by Dr. Waller and ...

  20. Sex Role Attitudes and Perceived Dating-Mating Choices of Youth.

    ERIC Educational Resources Information Center

    Hansen, Sally L.; Hicks, Mary W.

    1980-01-01

    Investigates the effects of gender, race, demographic, and sex role variables on date and mate preferences of 168 college students 18 to 22 years of age. Personality characteristics were found to be most important in choosing a date or mate. The study provides no support for the rating-dating complex described by Waller. (RMH)

  1. Leading Change in the Primary Science Curriculum

    ERIC Educational Resources Information Center

    Waller, Nicky; Baker, Chris

    2014-01-01

    Nicky Waller and Chris Baker believe that change can be a good thing and explain how their training has helped others to adjust to the new science curriculum. In September 2013, teachers across England received the definitive version of the new primary curriculum "Leading Change in the Primary Science Curriculum." This course aimed to…

  2. SHORTER MENSTRUAL CYCLES ASSOCIATED WITH CHLORINATION BY-PRODUCTS IN DRINKING WATER

    EPA Science Inventory

    Shorter Menstrual Cycles Associated with Chlorination by-Products in Drinking Water.
    Gayle Windham, Kirsten Waller, Meredith Anderson, Laura Fenster, Pauline Mendola, Shanna Swan. California Department of Health Services.

    In previous studies of tap water consumption we...

  3. STRAIN COMPARISON IN PREGNANT RATS OF ENDOCRINE RESPONSE TO BROMODICHLOROMETHANE: A DRINKING WATER DISINFECTION BY-PRODUCT

    EPA Science Inventory

    Bromodichloromethane (BDCM), a trihalomethane, is a by-product of the chlorination of drinking water. In an epidemiological study, consumption of drinking water with high levels of BDCM was associated with an increased risk of spontaneous abortion in pregnant women (Waller et al....

  4. TIME TO PREGNANCY IN RELATION TO TOTAL TRIHALOMETHANE LEVELS IN TAP WATER

    EPA Science Inventory

    Time to pregnancy in relation to total trihalomethane levels in tap water
    Shanna H. Swan, Cuirong Ren, Gayle C. Windham, Laura Fenster, Kirsten Waller. (University of Missouri and California Department of Health Services).

    We have previously reported increased risks o...

  5. Culture and Leadership in Educational Administration: A Historical Study of What Was and What Might Have Been

    ERIC Educational Resources Information Center

    Bates, Richard

    2006-01-01

    This paper examines the consequences for school leadership of the abandonment of Waller's insights into the school as a social organism and the embracing of the cult of efficiency as the foundation for the analysis of school culture. Tracing the separation of conception from execution, leadership from teaching, administration from education…

  6. 78 FR 19599 - Approval and Promulgation of Implementation Plans; Texas; Reasonably Available Control Technology...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-02

    ...The EPA is finalizing its proposal to approve revisions to the Texas State Implementation Plan (SIP) for the Houston/Galveston/ Brazoria (HGB) 1997 8-Hour ozone nonattainment Area (Area). The HGB Area consists of Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery and Waller counties. Specifically, we are finalizing our proposed approval of portions of two revisions to the......

  7. Blacks in Pop Music: A Short Story.

    ERIC Educational Resources Information Center

    Rickelman, Melinda

    1991-01-01

    A short history of black pop music includes artists who have changed pop music or culture and highlights from the 1920s into the 1980s, from Fats Waller to Michael Jackson. In black pop music, there is a direct line of influence from the sharecropper to the current Top 40. (SLD)

  8. What Doth It Profit? The Study of Mountain Religion.

    ERIC Educational Resources Information Center

    Salstrom, Paul; And Others

    1990-01-01

    Five papers examine mountain religion, focusing on Jeff Todd Titon's book, "Powerhouse of God: Speech, Chant, and Song in an Appalachian Baptist Church." Discussants include Paul Salstrom; Deborah Vansau McCauley; Howard Dorgan; Altina Waller; and Charles T. Davis. Titon responds, explaining his views and study of religion. (TES)

  9. Communication of Love and Decision-Making Power in Dating Relationships.

    ERIC Educational Resources Information Center

    Ting-Toomey, Stella

    A study explored the relationship between romantic love and decision making power in college students' dating relationships. W. Waller's theory that the person who is "least in love" gains power over the person who is relatively "more in love" was tested in terms of C. Safilios-Rothchild's typology of "Orchestration Power" (infrequent but…

  10. Brokenhearts: Dissolution of Romantic Relationships.

    ERIC Educational Resources Information Center

    Meeker, F. B.; La Fong, Carl

    Results of an investigation examining the dissolution of romantic relationships are analyzed. Men and women (N=105) who had ended romantic relationships were surveyed in structured individual interviews. Commonalities and differences in respondents' perceptions of the experience were examined. Specific tests were made of a corollary to Waller's…

  11. The Role of Personality in the Selection of a Major: With and without Vocational Self-Efficacy and Interests

    ERIC Educational Resources Information Center

    Larson, Lisa M.; Wu, Tsui Feng; Bailey, Donna C.; Gasser, Courtney E.; Bonitz, Verena S.; Borgen, Fred H.

    2010-01-01

    The purpose of this study is to examine the role of personality traits measured by the Multidimensional Personality Questionnaire (MPQ; [Tellegen, 2000] and [Tellegen and Waller, 2008]) in selecting educational majors. Personality traits were examined alone, and with the combination of Holland's hexagonal confidence domains, as measured by the…

  12. Correcting Distance Estimates by Interacting With Immersive Virtual Environments: Effects of Task and Available Sensory Information

    ERIC Educational Resources Information Center

    Waller, David; Richardson, Adam R.

    2008-01-01

    The tendency to underestimate egocentric distances in immersive virtual environments (VEs) is not well understood. However, previous research (A. R. Richardson & D. Waller, 2007) has demonstrated that a brief period of interaction with the VE prior to making distance judgments can effectively eliminate subsequent underestimation. Here the authors…

  13. Testing a Readable Writing Approach to Text Revision.

    ERIC Educational Resources Information Center

    Duffy, Thomas M.; Kabance, Paula

    1982-01-01

    The present findings imply that a readability formula is not an effective writing production criterion, even when the writer does not deliberately write to the formula. Comprehensibility of text might be better controlled through the proper use of the transformer concept (MacDonald-Ross and Waller). (Author/PN)

  14. Attachment Style and Dysfunctional Career Thoughts: How Attachment Style Can Affect the Career Counseling Process

    ERIC Educational Resources Information Center

    van Ecke, Yolanda

    2007-01-01

    This article examines the relationship between attachment style, measured by Experiences in Close Relationships-Revised (R C. Fraley, N. G. Waller, & K. A. Brennan, 2000), and dysfunctional career thoughts, measured by the Career Thoughts Inventory (CTI; J. P. J. Sampson, G. W. Peterson, J. G. Lenz, R. C. Reardon, & D. E. Saunders, 1994a). Two…

  15. Stretching the boundaries

    NASA Astrophysics Data System (ADS)

    2012-08-01

    Tom Waller of swimwear manufacturer Speedo's global research and development facility, Aqualab, talked to Nature Materials about the competitive sporting goods industry and the technology behind their new racing system that will be put to the test at the 2012 Olympic Games in London.

  16. Relationship of Purported Measures of Pathological and Nonpathological Dissociation to Self-Reported Psychological Distress and Fantasy Immersion

    ERIC Educational Resources Information Center

    Levin, Ross; Spei, Ekaterina

    2004-01-01

    In order to investigate both the psychometric structure of the Dissociative Experiences Survey (DES) and the discriminant validity of the DES-Taxon (Waller, Putnam, & Carlson, 1996) as a specific marker of pathological dissociation, 376 non-clinical community based respondents completed the DES and a battery of psychopathology and imaginative…

  17. TRIHALOMETHANE LEVELS IN HOME TAP WATER AND SEMEN QUALITY

    EPA Science Inventory

    Trihalomethane Levels in Home Tap Water and Semen Quality
    Laura Fenster, 1 Kirsten Waller, 2 Gayle Windham, 1 Tanya Henneman, 2 Meredith Anderson, 2 Pauline Mendola, 3 James W. Overstreet, 4 Shanna H. Swan5

    1California Department of Health Services, Division of Environm...

  18. CHLORINATION BY-PRODUCTS IN DRINKING WATER AND MENSTRUAL CYCLE FUNCTION

    EPA Science Inventory

    Chlorination by-Products in Drinking Water and Menstrual Cycle Function

    Gayle C. Windham1, Kirsten Waller2, Meredith Anderson2, Laura Fenster1, Pauline Mendola3, Shanna Swan4

    1California Department of Health Services, Division of Environmental and Occupational Disea...

  19. Space weathering: from laboratory to observations .

    NASA Astrophysics Data System (ADS)

    Brunetto, R.; Orofino, V.; Strazzulla, G.

    An ongoing research program in our laboratories is focusing on the effects of laser ablation and ion irradiation on silicates, meteorites, and ices, as a simulation of space weathering on Solar System minor bodies (asteroids, Trans-Neptunian Objects, etc.). Spectroscopic results show a general reddening and darkening of the various materials in the 0.3-2.7 mu m range. Laboratory data are then compared with observations, through spectral characterization and scattering models, indicating that space weathering is a very efficient process both in the inner and outer Solar System. In particular, we demonstrated that the majority of TNOs and Centaurs can develop an organic crust mantle produced after irradiation of simple C-bearing molecules. Another relevant result is that the exposure to surface space weathering of asteroid 832 Karin, as calculated from our experiments and models, is in agreement with a dynamical time-scale, i.e. the age of the corresponding Karin family.

  20. ASBMB Journal Club - Office of Cancer Clinical Proteomics Research

    Cancer.gov

    On Wednesday, November 12, 2014 from 2:00 PM to 3:00 PM EST, Daniel Liebler, PhD (Vanderbilt University) and Karin Rodland, PhD (Pacific Northwestern National Laboratory) and Ruedi Aebersold, PhD (Swiss Federal Institute of Technology) will share their research insight as part of the ASBMB Journal Club.  Both Doctors Liebler and Rodland are Principal Investigators in the NCI’s Clinical Proteomic Tumor Analysis Consortium.

  1. Perspectives on Positioning, Interaction, and Learning in Small-Group Discussion: Possibilities for Extending the Analytic Lens

    ERIC Educational Resources Information Center

    Kittleson, Julie M.; Wilson, Rachel E.

    2014-01-01

    In this forum piece, we respond to Karin Due's study of social dynamics in groups of students in physics class and gender issues that play out in this context. We discuss two threads that appear in Due's paper: one pertains to patterns of talk within groups and how these patterns open up possibilities for learning, the other pertains to…

  2. Asperity contact theories: Do they predict linearity between contact area and load?

    NASA Astrophysics Data System (ADS)

    Carbone, G.; Bottiglione, F.

    During the last few years, the scientific community has been debating about which theory of contact between rough surfaces can be considered as the most accurate. The authors have been attracted by such a discussion and in this paper try to give their personal thought and contribution to this debate. We present a critical analysis of the principal contact theories of rough surfaces. We focus on the multiasperity contact models (which are all based on the original idea of Greenwood and Williamson (GW) [1966. Proc. R. Soc. London A 295, 300]), and also briefly discuss a relatively recent contact theory developed by Persson [2001. J. Chem. Phys. 115, 3840]. For small loads both asperity contact models and Persson's theory predict a linear relation between the area of true contact and the applied external load, but the two theories differ for the constant of proportionality. However, this is not the only difference between the two approaches. Indeed, we show that the fully calculated predictions of asperity contact models very rapidly deviates from the predicted linear relation already for very small and in many cases unrealistic vanishing applied loads and contact areas. Moreover, this deviation becomes more and more important as the PSD breadth parameter α (as defined by Nayak) increases. Therefore, the asymptotic linear relation of multiasperity contact theories turns out to be only an academic result. On the contrary, Persson's theory is not affected by α and shows a linear behavior between contact area and load up to 10-15% of the nominal contact area, i.e. for physical reasonable loads. The authors also prove that, at high separation, all multiasperity contact models, which take into account the influence of summit curvature variation as a function of summit height, necessarily converge to a (slightly) improved version of the GW model, which, therefore, remains one of the most important milestones in the field of contact mechanics of rough surfaces.

  3. In-situ X-ray diffraction studies of the phase transformations and structural states of B2, R and B19′ phases in Ti{sub 49.5}Ni{sub 50.5} alloy

    SciTech Connect

    Ostapenko, Marina G.; Meisner, Ludmila L.; Lotkov, Aleksandr I. Gudimova, Ekaterina Y.; Zakharova, Margarita A.

    2015-10-27

    The martensitic transformation, Debye–Waller factor, mean-square atomic displacements and the coefficient of thermal expansion on cooling of the Ti{sub 49.5}Ni{sub 50.5} shape memory alloy were examined using in-situ X-ray diffraction. It was revealed B2→R (T{sub R} ≡ T = 273 ± 10 K) along with B2→B19’ (M{sub s} ≡ T = 273 ± 10 K) transitions occur. It was found that Debye–Waller factor and mean-square displacement of B2 phase undergo significant increase as functions of temperature when phase transition B2→R and B2→B19’ take place. The analysis of the thermal expansion coefficient of the B2 phase indicates that the value of a increases almost linearly while cooling.

  4. In-situ X-ray diffraction studies of the phase transformations and structural states of B2, R and B19' phases in Ti49.5Ni50.5 alloy

    NASA Astrophysics Data System (ADS)

    Ostapenko, Marina G.; Meisner, Ludmila L.; Lotkov, Aleksandr I.; Zakharova, Margarita A.; Gudimova, Ekaterina Y.

    2015-10-01

    The martensitic transformation, Debye-Waller factor, mean-square atomic displacements and the coefficient of thermal expansion on cooling of the Ti49.5Ni50.5 shape memory alloy were examined using in-situ X-ray diffraction. It was revealed B2→R (TR ≡ T = 273 ± 10 K) along with B2→B19' (Ms ≡ T = 273 ± 10 K) transitions occur. It was found that Debye-Waller factor and mean-square displacement of B2 phase undergo significant increase as functions of temperature when phase transition B2→R and B2→B19' take place. The analysis of the thermal expansion coefficient of the B2 phase indicates that the value of a increases almost linearly while cooling.

  5. A search for T Tauri stars and related objects: Archival photometry of candidate variables in V733 Cep field

    NASA Astrophysics Data System (ADS)

    Jurdana-Šepić, R.; Poljančić Beljan, I.

    Searching for T Tauri stars or related early type variables we carried out a BVRI photometric measurements of five candidates with positions within the field of the pre-main sequence object V733 Cephei (Persson's star) located in the dark cloud L1216 near to Cepheus OB3 Association: VES 946, VES 950, NSV 14333, NSV 25966 and V385 Cep. Their magnitudes are determined on the plates from Asiago Observatory historical photographic archive exposed 1971 - 1978. We provide finding charts for program stars and comparison sequence stars, magnitude estimations, magnitude mean values and BVR_cI_c light curves of program stars.

  6. Nanotribology and Nanoscale Friction

    SciTech Connect

    Guo, Yi; Qu, Zhihua; Braiman, Yehuda; Zhang, Zhenyu; Barhen, Jacob

    2008-01-01

    Tribology is the science and technology of contacting solid surfaces in relative motion, including the study of lubricants, lubrication, friction, wear, and bearings. It is estimated that friction and wear cost the U.S. economy 6% of the gross national product (Persson, 2000). For example, 5% of the total energy generated in an automobile engine is lost to frictional resistance. The study of nanoscale friction has a technological impact in reducing energy loss in machines, in microelectromechanical systems (MEMS), and in the development of durable, low-friction surfaces and ultra-thin lubrication films.

  7. Infrared recombination lines of hydrogen from young objects in the southern Galactic plane

    NASA Technical Reports Server (NTRS)

    Beck, Sara C.; Fischer, Jacqueline; Smith, Howard A.

    1991-01-01

    Near infrared recombination lines of hydrogen are observed in twelve young objects in the southern Galactic plane. The sample includes Herbig-Haro objects and IRAS dark-cloud point sources from the 1987 catalog of Persson and Campbell. In four of the IRAS sources two or three infrared lines are measured, and their intensity ratios are consistent with models of optically thick ionized winds. The intrinsic line shapes, retrieved from maximum-entropy deconvolutions, indicate gas velocities of 100 km/s or more as expected from ionized winds. These sources are apparently embedded pre-main-sequence objects with outflows. They include some of the brightest known YSOs.

  8. Water-level altitudes in wells completed in the Jasper aquifer, greater Houston area, Texas, Spring 2000

    USGS Publications Warehouse

    Coplin, L.S.

    2001-01-01

    This report, prepared in cooperation with the Harris-Galveston Coastal Subsidence District, presents a map showing the approximate water-level altitudes in spring 2000 in wells completed in the Jasper aquifer (back of page). The most recent previously published water-level-altitude map for the Jasper aquifer in the region is by Popkin (1971). The study area includes Montgomery County and parts of Harris, Waller, Grimes, and Walker Counties.

  9. Comparing ultrafast surface and bulk heating using time-resolved electron diffraction

    SciTech Connect

    Streubühr, C.; Kalus, A.; Zhou, P. Kammler, M.; Linde, D. von der; Ligges, M.; Hanisch-Blicharski, A.; Bovensiepen, U.; Horn-von Hoegen, M.

    2014-04-21

    From measurements of the transient Debye-Waller effect in Bismuth, we determine the buildup time of the random atomic motion resulting from the electronic relaxation after short pulse laser excitation. The surface sensitive reflection high energy electron diffraction and transmission electron diffraction yield a time constant of about 12 ps and 3 ps, respectively. The different energy transfer rates indicate relatively weak coupling between bulk and surface vibrational modes.

  10. Centenary of tele-electrocardiography and telephonocardiography.

    PubMed

    Hjelm, N M; Julius, H W

    2005-01-01

    In the history of electrocardiography the names of two physiologists stand out: Augustus Waller (1865-1922) and Willem Einthoven (1860-1927). Waller was the first to show that the beating heart produces a weak electric potential, which can be registered by a measuring device connected to electrodes attached to the skin. Einthoven developed a 'string' galvanometer, which was much faster and more sensitive than the system used by Waller. Einthoven's electrocardiograph was ready for use in 1903. To facilitate investigations of patients Einthoven connected his instrument to the Academic Hospital in Leyden, by a telephone line, as suggested by his engineering colleague Johannes Bosscha in Delft. The first successful tele-electrocardiogram was transmitted on Sunday 22 March 1905. The heart tones were registered by wiring a specially developed microphone placed on the subject's chest to another string galvanometer. The event was therefore a first both for tele-electrocardiography and for telephonocardiography. We are still awaiting the full-scale implementation of these achievements, 100 years later. PMID:16238834

  11. Annual compilation and analysis of hydrologic data for urban studies in the Austin, Texas Metropolitan Area, 1971

    USGS Publications Warehouse

    Tovar, F.H.

    1973-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, began hydrologic studies in the Austin urban area in 1954. The objectives of this project are as follows: 1. To determine the effects of progressive urbanization on infiltration, rates of peak discharge, and rainfall-runoff relations in the Waller Creek watershed. 2. To provide rainfall-and-runoff data from the rural Wilbarger Creek watershed to be used for comparative purposes in determining the effects of existing and progressive urbanization in the Waller Creek watershed. 3. To provide applied research facilities for studies at the University of Texas at Austin. The purpose of this report is to present rainfall-and-runoff data for the Waller Creek and Wilbarger Creek study areas for the 1971 water year (October 1, 1970, to September 30, 1971). To facilitate the publication and distribution of this report at the earliest feasible time, certain material has been included that does not conform to the formal publication standards of the U.S. Geological Survey.

  12. Physical properties of asteroid dust bands and their sources

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Vokrouhlický, David; Bottke, William F.; Sykes, Mark

    2006-03-01

    Disruptive collisions in the main belt can liberate fragments from parent bodies ranging in size from several micrometers to tens of kilometers in diameter. These debris bodies group at initially similar orbital locations. Most asteroid-sized fragments remain at these locations and are presently observed as asteroid families. Small debris particles are quickly removed by Poynting-Robertson drag or comminution but their populations are replenished in the source locations by collisional cascade. Observations from the Infrared Astronomical Satellite (IRAS) showed that particles from particular families have thermal radiation signatures that appear as band pairs of infrared emission at roughly constant latitudes both above and below the Solar System plane. Here we apply a new physical model capable of linking the IRAS dust bands to families with characteristic inclinations. We use our results to constrain the physical properties of IRAS dust bands and their source families. Our results indicate that two prominent IRAS bands at inclinations ≈2.1° and ≈9.3° are byproducts of recent asteroid disruption events. The former is associated with a disruption of a ≈30-km asteroid occurring 5.8 Myr ago; this event gave birth to the Karin family. The latter came from the breakup of a large >100-km-diameter asteroid 8.3 Myr ago that produced the Veritas family. Using an N-body code, we tracked the dynamical evolution of ≈10 6 particles, 1 μm to 1 cm in diameter, from both families. We then used these results in a Monte Carlo code to determine how small particles from each population undergo collisional evolution. By computing the thermal emission of particles, we were able to compare our results with IRAS observations. Our best-fit model results suggest the Karin and Veritas family particles contribute by 5-9% in 10-60-μm wavelengths to the zodiacal cloud's brightness within 50° latitudes around the ecliptic, and by 9-15% within 10° latitudes. The high brightness of

  13. "small problems, Big Trouble": An Art and Science Collaborative Exhibition Reflecting Seemingly small problems Leading to Big Threats

    NASA Astrophysics Data System (ADS)

    Waller, J. L.; Brey, J. A.

    2014-12-01

    "small problems, Big Trouble" (spBT) is an exhibition of artist Judith Waller's paintings accompanied by text panels written by Earth scientist Dr. James A. Brey and several science researchers and educators. The text panels' message is as much the focus of the show as the art--true interdisciplinarity! Waller and Brey's history of art and earth science collaborations include the successful exhibition "Layers: Places in Peril". New in spBT is extended collaboration with other scientists in order to create awareness of geoscience and other subjects (i.e. soil, parasites, dust, pollutants, invasive species, carbon, ground water contaminants, solar wind) small in scale which pose significant threats. The paintings are the size of a mirror, a symbol suggesting the problems depicted are those we increasingly need to face, noting our collective reflections of shared current and future reality. Naturalistic rendering and abstract form in the art helps reach a broad audience including those familiar with art and those familiar with science. The goal is that gallery visitors gain greater appreciation and understanding of both—and of the sober content of the show as a whole. "small problems, Big Trouble" premiers in Wisconsin April, 2015. As in previous collaborations, Waller and Brey actively utilize art and science (specifically geoscience) as an educational vehicle for active student learning. Planned are interdisciplinary university and area high school activities linked through spBT. The exhibition in a public gallery offers a means to enhance community awareness of and action on scientific issues through art's power to engage people on an emotional level. This AGU presentation includes a description of past Waller and Brey activities: incorporating art and earth science in lab and studio classrooms, producing gallery and museum exhibitions and delivering workshops and other presentations. They also describe how walking the paths of several past earth science

  14. Circuit racing, track texture, temperature and rubber friction

    NASA Astrophysics Data System (ADS)

    Sharp, R. S.; Gruber, P.; Fina, E.

    2016-04-01

    Some general observations relating to tyre shear forces and road surfaces are followed by more specific considerations from circuit racing. The discussion then focuses on the mechanics of rubber friction. The classical experiments of Grosch are outlined and the interpretations that can be put on them are discussed. The interpretations involve rubber viscoelasticity, so that the vibration properties of rubber need to be considered. Adhesion and deformation mechanisms for energy dissipation at the interface between rubber and road and in the rubber itself are highlighted. The enquiry is concentrated on energy loss by deformation or hysteresis subsequently. Persson's deformation theory is outlined and the material properties necessary to apply the theory to Grosch's experiments are discussed. Predictions of the friction coefficient relating to one particular rubber compound and a rough surface are made using the theory and these are compared with the appropriate results from Grosch. Predictions from Persson's theory of the influence of nominal contact pressure on the friction coefficient are also examined. The extent of the agreement between theory and experiment is discussed. It is concluded that there is value in the theory but that it is far from complete. There is considerable scope for further research on the mechanics of rubber friction.

  15. Molecular dynamics study of contact mechanics: contact area and interfacial separation from small to full contact

    NASA Astrophysics Data System (ADS)

    Yang, Chunyan; Persson, Bo

    2008-03-01

    We report a molecular dynamics study of the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. We study the contact area and the interfacial separation from small contact (low load) to full contact (high load). For small load the contact area varies linearly with the load and the interfacial separation depends logarithmically on the load [1-4]. For high load the contact area approaches to the nominal contact area (i.e., complete contact), and the interfacial separation approaches to zero. The present results may be very important for soft solids, e.g., rubber, or for very smooth surfaces, where complete contact can be reached at moderate high loads without plastic deformation of the solids. References: [1] C. Yang and B.N.J. Persson, arXiv:0710.0276, (to appear in Phys. Rev. Lett.) [2] B.N.J. Persson, Phys. Rev. Lett. 99, 125502 (2007) [3] L. Pei, S. Hyun, J.F. Molinari and M.O. Robbins, J. Mech. Phys. Sol. 53, 2385 (2005) [4] M. Benz, K.J. Rosenberg, E.J. Kramer and J.N. Israelachvili, J. Phy. Chem. B.110, 11884 (2006)

  16. The resolution of inflammation: anti-inflammatory roles for NF-kappaB.

    PubMed

    Lawrence, Toby; Fong, Carol

    2010-04-01

    Inflammation is a salutary response to insult or injury that normally resolves with no detriment to the host. While the mechanisms and mediators that regulate the onset of inflammation have been well characterized we still know relatively little about the endogenous mechanisms that terminate the inflammatory response (Lawrence and Gilroy, 2007). Nuclear factor (NF)-kappaB is a generic term for a family of ubiquitous transcription factors with diverse physiological functions (Bonizzi and Karin, 2004; Caamano and Hunter, 2002). NF-kappaB transcription factors are formed by dimerisation of Rel proteins; RelA (p65), c-Rel, RelB, p50, p52. Various hetero or homodimers of Rel proteins can be formed in a tissue and stimulus specific manner, genetic evidence suggests these transcription factors have a critical role in cell survival and pro-inflammatory signalling pathways, which have been extensively reviewed elsewhere (Bonizzi and Karin, 2004; Caamano and Hunter, 2002). The critical role for NF-kappaB in pro-inflammatory gene expression has led to an enormous effort to develop inhibitors of this pathway for the treatment of chronic inflammation (Karin et al., 2004). However, recent research using modern molecular genetic approaches has revealed new anti-inflammatory roles for NF-kappaB that may have important implications for targeting this pathway in the treatment of inflammatory diseases. In this review we will discuss the emerging role of NF-kappaB in the resolution of inflammation and some of the potential mechanisms attributed to this function. PMID:20026420

  17. Koronis binaries and the role of families in binary frequency

    NASA Astrophysics Data System (ADS)

    Merline, W. J.; Tamblyn, P. M.; Nesvorny, D.; Durda, D. D.; Chapman, C. R.; Dumas, C.; Owen, W. M.; Storrs, A. D.; Close, L. M.; Menard, F.

    2005-08-01

    Our ground-based adaptive optics observations of many larger Koronis members show no binaries, while our HST survey of smaller Koronis members (say smaller than 10 km) shows a surprising 20% binary fraction. Admittedly, this is from small-number statistics, but we nonetheless calculate a 99% confidence that the binary fraction is different from the 2% we observe among the larger (over 20km) main belt asteroids as a whole. In addition, we estimate that among the two young families (Karin and Veritas) that we surveyed for binaries in our HST Cy 13 program, the binary fraction appears to be less than 5%. These young families both have significantly smaller progenitors than the Koronis family. We have speculated that progenitor size may be a more important factor than age in determination of binary frequency. But here we suggest an alternative idea, that the binary fraction may be more related to what part of the family's size distribution is sampled. Our HST program targeted objects of the same physical sizes, but was clearly sampling further down the size distribution (to smaller sizes, relative to the largest remnant) in the Koronis sample than was the case for Karin and Veritas, which we sampled mostly at the larger sizes, relatively. Our SPH collision models are estimating the typical size-frequency distributions to be expected from catastrophic and non-catastrophic impact events. But they are also appear to be showing that the largest fragments from a collision are less likely to form binaries (as co-orbiting ejecta pairs) than are the smaller fragments. Thus, it might be expected that we would have found fewer binaries among Karin and Veritas than among the Koronis sample. In fact, models of the Karin breakup show binary formation to be unlikely in the size range measured. It some might be tempted to tie the small end of the main-belt binary population to the binaries seen among the NEAs (also small and also showing about 20% fraction), given the 20% fraction

  18. The Surface Water and Ocean Topography Mission: a mission concept to study the world's oceans and fresh water

    NASA Astrophysics Data System (ADS)

    Vaze, Parag; Albuys, Vincent; Esteban-Fernandez, Daniel; Lafon, Thierry; Lambin, Juliette; Mallet, Alain; Rodriguez, Ernesto

    2010-10-01

    The Surface Water and Ocean Topography (SWOT) is a planned satellite mission to study the world's oceans and terrestrial surface water bodies. The SWOT mission concept has been proposed jointly by the global Hydrology and Oceanography science communities to make the first global survey of the Earth's surface water, observe the fine details of the ocean's surface topography, and measure how water bodies change over time. SWOT was one of 15 missions listed in the 2007 National Research Council's Decadal Survey for Earth science as a mission that NASA should implement in the incoming decade. This mission concept builds upon the heritage of prior missions and technologies such as Topex/Poseidon, Jason-1/ 2, the Shuttle Radar Topography Mission (SRTM), and the initial development of the Wide Swatch Ocean Altimeter intended for the Ocean Surface Topography Mission/Jason-2. The key measurement capability for SWOT is provided by a Ka-band synthetic aperture radar interferometer (KaRIn). With an orbit altitude of 970 km, the KaRIn instrument provides a high-resolution swath width of 120 km enabling global coverage (~90%) of the world's ocean's and fresh water bodies. The KaRIn measurement is being designed to provide a spatial resolution of 1 km for the oceans (after on-board processing), and 100 m for land water, both at centimetric accuracy. An additional instrument suite similar to the Jason series will complement KaRIn: a Ku-band nadir altimeter, a Microwave Radiometer and Precision Orbit Determination (POD) systems. To enable this challenging measurement performance, the SWOT mission concept is designed to overcome several challenges, such as very high raw data rate (320 Mbps), large on-board data volumes, high power demand, stringent pointing and stability requirements, and ground data processing systems, to produce meaningful science data products to our user community. The SWOT mission concept is being developed as a cooperative effort between NASA and CNES. This

  19. Order parameters from image analysis: a honeycomb example

    NASA Astrophysics Data System (ADS)

    Kaatz, Forrest H.; Bultheel, Adhemar; Egami, Takeshi

    2008-11-01

    Honeybee combs have aroused interest in the ability of honeybees to form regular hexagonal geometric constructs since ancient times. Here we use a real space technique based on the pair distribution function (PDF) and radial distribution function (RDF), and a reciprocal space method utilizing the Debye-Waller Factor (DWF) to quantify the order for a range of honeycombs made by Apis mellifera ligustica. The PDFs and RDFs are fit with a series of Gaussian curves. We characterize the order in the honeycomb using a real space order parameter, OP 3 , to describe the order in the combs and a two-dimensional Fourier transform from which a Debye-Waller order parameter, u, is derived. Both OP 3 and u take values from [0, 1] where the value one represents perfect order. The analyzed combs have values of OP 3 from 0.33 to 0.60 and values of u from 0.59 to 0.69. RDF fits of honeycomb histograms show that naturally made comb can be crystalline in a 2D ordered structural sense, yet is more ‘liquid-like’ than cells made on ‘foundation’ wax. We show that with the assistance of man-made foundation wax, honeybees can manufacture highly ordered arrays of hexagonal cells. This is the first description of honeycomb utilizing the Debye-Waller Factor, and provides a complete analysis of the order in comb from a real-space order parameter and a reciprocal space order parameter. It is noted that the techniques used are general in nature and could be applied to any digital photograph of an ordered array.

  20. Slow Wave Conduction Patterns in the Stomach: From Waller’s Foundations to Current Challenges

    PubMed Central

    2015-01-01

    This review provides an overview of our understanding of motility and slow wave propagation in the stomach. It begins by reviewing seminal studies conducted by Walter Cannon and Augustus Waller on in vivo motility and slow wave patterns. Then our current understanding of slow wave patterns in common laboratory animals and humans is presented. The implications of slow wave dysrhythmic patterns that have been recorded in animals and patients suffering from gastroparesis are discussed. Finally, current challenges in experimental methods and techniques, slow wave modulation and the use of mathematical models are discussed. PMID:25313679

  1. Higher-Order-Mode Diagnostics and Suppression in Superconducting Cavities (HOMSC12)

    NASA Astrophysics Data System (ADS)

    Jones, Roger M.

    2014-01-01

    From the 25th of June through Wednesday lunchtime of the 27th of June 2012 the Cockcroft Institute and ASTeC hosted an ICFA supported mini workshop on Higher-Order-Mode Diagnostics and Suppression in Superconducting Cavities (HOMSC12). The local organizing committee for this international workshop was chaired by S. Buckley (ASTeC/STFC), conference administration by S. Waller (ASTeC/STFC), and the scientific program committee by R.M. Jones (Cockcroft Institute/University of Manchester).

  2. Coverage-dependent quantum versus classical scattering of thermal neon atoms from Li/Cu(100).

    PubMed

    Maclaren, D A; Huang, C; Levi, A C; Allison, W

    2008-09-01

    We show that subtle variations in surface structure can enhance quantum scattering and quench atom-surface energy transfer. The scattering of thermal energy neon atoms from a lithium overlayer on a copper substrate switches between a classical regime, dominated by multiphonon interactions, and a quantum regime, dominated by elastic diffraction. The transition is achieved by simple tailoring of the lithium coverage and quantum scattering dominates only in the narrow coverage range of theta=0.3-0.6 ML. The results are described qualitatively using a modified Debye-Waller model that incorporates an approximate quantum treatment of the adsorbate-substrate vibration. PMID:19044885

  3. FEFF5: An ab initio multiple scattering XAFS code

    SciTech Connect

    Rehr, J.J.; Zabinsky, S.I.

    1992-12-31

    FEFF5 is an efficient automated code which calculates multiple scattering (MS) curved wave XAFS spectra for molecules and solids. The theoretical ingredients and approximations contained in the code are revised, with the aim of describing the how XAFS spectra are efficiently simulated. The FEFF5 code consists of 4 independent modules: a scattering potential and phase shift module, a path finder module, a scattering amplitude module and an XAFS module. Multiple scattering Debye-Waller factors are built in using a correlated Debye model.

  4. FEFF5: An ab initio multiple scattering XAFS code. [In FORTRAN 77

    SciTech Connect

    Rehr, J.J.; Zabinsky, S.I.

    1992-01-01

    FEFF5 is an efficient automated code which calculates multiple scattering (MS) curved wave XAFS spectra for molecules and solids. The theoretical ingredients and approximations contained in the code are revised, with the aim of describing the how XAFS spectra are efficiently simulated. The FEFF5 code consists of 4 independent modules: a scattering potential and phase shift module, a path finder module, a scattering amplitude module and an XAFS module. Multiple scattering Debye-Waller factors are built in using a correlated Debye model.

  5. Experimental Determination of Structure Factors of Titanium Aluminum and Silicon

    NASA Astrophysics Data System (ADS)

    Subramanian, Swaminathan

    Brittleness of TiAl has been attributed to strong directional bonding by a number of researchers. Their predictions have been based on theoretical calculations of electron charge density distribution. It is necessary to complement these predictions by experimental measurements. The work described in this thesis, aimed towards that end, involves measurement of Debye-Waller factors by four circle x-ray diffraction and of structure factors by energy filtered convergent beam electron diffraction CBED methods. Stoichiometric single crystals are required for the measurement of Debye-Waller factors by the four circle x-ray diffraction method. Because of constraints imposed by the phase diagram only non-stoichiometric single crystal of TiAl are available. Measurement of Debye-Waller parameters have been attempted by using aluminum rich TiAl single crystals of compositions Ti54at%Al and Ti56at%Al. The symmetry of L1_0 structure of TiAl dictates that all reflections with Miller indices (hkl) not satisfying the condition h + k = 2n should be extinct. However, during the x-ray diffraction experiments diffuse diffracted intensities were observed for reflections of h + k = 2n + 1 type. This indicates the possibility of occupation of the excess Al atoms on the Ti-sites. If the excess Al atom preferentially occupies one of the Ti-sites, it would lead to the formation of L1_2 type TiAl_3 unit cells within the TiAl lattice. This notion has been further verified by least-squares refinement of the data obtained from Ti54at%Al single crystal. Also Debye-Waller factor values were different for equivalent Ti-sites in TiAl. The CBED method was developed for accurate structure factor measurement. Factors such as limitation due to the angular resolution of the aperture and complex matrix and perturbation treatment of absorption have been considered. Computer routines, incorporating these factors, have been developed for the calculation of CBED patterns and for matching the rocking curves

  6. Quasi-elastic neutron scattering studies of protein dynamics. Progress report, November 1, 1992--May 25, 1993

    SciTech Connect

    Rorschach, H.E.

    1993-05-25

    Results that shed new light on the study of protein dynamics were obtained by quasi-elastic neutron scattering. The triple axis instrument H-9 supplied by the cold source was used to perform a detailed study of the quasi-elastic spectrum and the Debye-Waller factor for trypsin in powder form, in solution, and in crystals. A preliminary study of myoglobin crystals was also done. A new way to view the results of quasi-elastic scattering experiments is sketched, and the data on trypsin are presented and analyze according to this new picture.

  7. Quasi-elastic neutron scattering studies of protein dynamics

    SciTech Connect

    Rorschach, H.E.

    1993-05-25

    Results that shed new light on the study of protein dynamics were obtained by quasi-elastic neutron scattering. The triple axis instrument H-9 supplied by the cold source was used to perform a detailed study of the quasi-elastic spectrum and the Debye-Waller factor for trypsin in powder form, in solution, and in crystals. A preliminary study of myoglobin crystals was also done. A new way to view the results of quasi-elastic scattering experiments is sketched, and the data on trypsin are presented and analyze according to this new picture.

  8. Review of the highlights of X-ray studies of liquid metal surfaces

    SciTech Connect

    Pershan, P. S.

    2014-12-14

    X-ray studies of the interface between liquid metals and their coexisting vapor are reviewed. After a brief discussion of the few elemental liquid metals for which the surface Debye-Waller effect is sufficiently weak to allow measurement, this paper will go on to discuss the various types of surface phenomena that have been observed for liquid metal alloys. These include surface adsorption, surface freezing, surface aggregation of nm size atomic clusters, and surface chemistry that leads to new 3D crystalline phases.

  9. [100 years' of clinical electrocardiography].

    PubMed

    Bergovec, Mijo

    2003-01-01

    In 1903 Willem Einthoven published in Pflügers Arch his classic article on the investigation of human electrocardiogram by his string galvanometer. Many historians of medicine, Einthoven also marked that publication as the beginning of clinical electrocardiography. Many investigators like Galvani, Manteucci, Kölliker, Müller, Lipmann, Waller, Ader, Einthoven, Lewis, Wilson and others participated in creation and development of electrocardiogram. From that time electrocardiogram quickly became, and has remained the most essential diagnostic laboratory tool in investigation of heart diseases. The aim of this article is to remind us of the beginning of this part of cardiology 100 years ago. PMID:15209030

  10. Historical aspects of electrocardiography.

    PubMed

    Krikler, D M

    1987-08-01

    One hundred years ago, Augustus Desiré Waller recorded the human electrocardiogram for the first time, using a capillary electrometer. Electrocardiography only became clinically relevant in 1901 when Willem Einthoven devised his string galvanometer for this purpose. Sir Thomas Lewis was the key figure in showing the value of the electrocardiography for the diagnosis of disorders of cardiac rhythm and conduction, but many others amplified the technique to encompass the assessment of structural heart disease, especially when due to ischemia. Knowledge of their role and work gives us a better perspective when considering the development of surface electrocardiography. PMID:3319160

  11. Strangles: a pathogenic legacy of the war horse.

    PubMed

    Waller, Andrew S

    2016-01-23

    Strangles, characterised by pyrexia followed by abscessation of the lymph nodes of the head and neck, was first described in 1251 (Rufus 1251) and the causative agent, Streptococcus equi, was identified in 1888 (Schutz 1888). However, despite more than a century of research into this disease, strangles remains the most frequently diagnosed infection of horses with over 600 outbreaks being identified in the UK alone each year (Parkinson and others 2011). Here, Andrew Waller reviews some of the recent advances in the understanding of the evolution of S equi and puts this into the context of preventing and resolving outbreaks of infection. PMID:26795860

  12. The material dependence of temperature measurement resolution in thermal scanning electron microscopy

    SciTech Connect

    Wu, Xiaowei; Hull, Robert

    2013-03-18

    Thermal scanning electron microscopy is a recently developed temperature mapping technique based on thermal diffuse scattering in electron backscatter diffraction in a scanning electron microscope. It provides nano-scale and non-contact temperature mapping capabilities. Due to the specific temperature sensitive mechanism inherent to this technique, the temperature resolution is highly material dependent. A thorough investigation of what material properties affect the temperature resolution is important for realizing the inherent temperature resolution limit for each material. In this paper, three material dependent parameters-the Debye-Waller B-factor temperature sensitivity, backscatter yield, and lattice constant-are shown to control the temperature resolution.

  13. Anomalous behavior of LEED beam intensity during annealing

    NASA Astrophysics Data System (ADS)

    Fu, Tsu-Yi; Liu, T. F.; Su, C. W.; Shern, C. S.; Chen, R. H.

    2000-10-01

    Low-energy electron diffraction was used to study the annealing effects of 1 ML Ag on the ultra-thin-film Co/Pt (111). The behavior of the specular beam intensity versus temperature is anomalous. Besides the normal Debye-Waller effect, a bend occurs at 550 K, and a dramatic increase occurs at a higher temperature. A corresponding study by Auger electron spectroscopy and ultraviolet photoelectron spectroscopy indicates that the bend results from the Co inter-diffusion. The anomalous increase indicates that a more stable state forms at a higher temperature. The Co coverage plays an important role in determining the turning temperature. Possible mechanisms are discussed.

  14. The effects of urbanization on floods in the Austin metropolitan area, Texas

    USGS Publications Warehouse

    Veenhuis, J.E.; Gannett, D.G.

    1986-01-01

    The effects of urbanization on flood peaks in streams in the Austin metropolitan area Texas were studied in two separate analyses. In the first analysis, annual peak discharge records at 13 streamflow gaging sites were used to compute a recorded flood frequency relation for each site. Rainfall and streamflow data for 10 to 20 storms for each of these sites were used to simulate 55 annual peak discharges. These simulated discharges also were used to develop a flood frequency relation at each site. The flood frequency relations from recorded and generated data were then combined by weighting the recorded flood frequency by the years of record at each site to produce a combined (or weighted) flood frequency at each site. Flood frequencies for all 13 sites were subsequently regressed against basin characteristics at each site to determine possible effects of urbanization. The regression analysis of the combined flood frequency data for the 13 sites yielded an equation for estimating floods of a given recurrence interval at ungaged sites in the Austin area, as a function of the contributing drainage area, the total impervious area percentage, and basin shape. The regression equation estimates that a near fully developed hypothetical drainage basin (impervious area percentage, 45%) would have discharges for the 2 yr and 100 yr recurrence interval that are 99% and 73% greater, respectively, than discharges for those frequencies from a rural drainage basin (impervious percentage, 0). In the second analysis, records at one streamflow gaging site on Waller Creek were analyzed for changes in rainfall-runoff and flood frequency relations due to urbanization. Annual peak discharges from 1956 to 1980 and data from a total of 80 storms at the Waller Creek site were analyzed. Both analyses showed increases comparable to those predicted using the equations developed from the 13-station analysis. The last 14 years of record (the near fully developed land use stage for the Waller

  15. Making babies without sex: the law and the profits.

    PubMed

    Annas, G J

    1984-12-01

    The author reviews scientific and societal developments in artificial reproductive technologies during the past year in the U.S., the United Kingdom, and Australia. Successful births resulted from surrogate embryo transfer and from transfer of an embryo following in vivo fertilization. Recommendations on social policy were made by Australia's Waller Committee, Britain's Warnock Committee, and U.S. congressional hearings. Annas stresses the need to define parenthood and restrict commercialization of childbearing through the enactment of legislation, the promulgation of guidelines for sound clinical practice, and the establishment of an interdisciplinary body to monitor developments and the need for further regulation. PMID:6507700

  16. A New Approach for Imposing Artificial Viscosity for Explicit Discontinuous Galerkin Scheme

    NASA Astrophysics Data System (ADS)

    See, Yee Chee; Lv, Yu; Ihme, Matthias

    2014-11-01

    The development of high-order numerical methods for unstructured meshes has been a significant area of research, and the discontinuous Galerkin (DG) method has found considerable interest. However, the DG-method exhibits robustness issues in application to flows with discontinuities and shocks. To address this issue, an artificial viscosity method was proposed by Persson et al. for steady flows. Its extension to time-dependent flows introduces substantial time-step restrictions. By addressing this issue, a novel method, which is based on an entropy formulation, is proposed. The resulting scheme doesn't impose restrictions on the CFL-constraint. Following a description of the formulation and the evaluation of the stability, this newly developed artificial viscosity scheme is demonstrated in application to different test cases.

  17. VizieR Online Data Catalog: Distant radio galaxies in southern hemisphere (Bryant+, 2009)

    NASA Astrophysics Data System (ADS)

    Bryant, J. J.; Broderick, J. W.; Johnston, H. M.; Hunstead, R. W.; Gaensler, B. M.; De Breuck, C.

    2015-06-01

    Radio images were obtained with the Australia Telescope Compact Array (ATCA) in several runs in 2003-06. Both 1384- and 2368-MHz images were needed to pinpoint the K-band identification. Higher resolution observations were obtained for 29 sources on UT 2008 January 16-20. Our initial Ks-band imaging was begun on the 3.9-m Anglo-Australian Telescope's (AAT) Infrared Imager and Spectrograph (IRIS2) detector on two observing runs on 2004 August 3-5 and 2005 June 21-24. We observed 126 targets in Ks-band with Persson's Auxiliary Nasmyth Infrared Camera (PANIC;) on the 6.5-m Magellan Baade telescope at Las Campanas Observatory on 2006 June 11-13, 2006 November 8-10 and 2007 April 2-4. (2 data files).

  18. Rubber friction on road surfaces: Experiment and theory for low sliding speeds.

    PubMed

    Lorenz, B; Oh, Y R; Nam, S K; Jeon, S H; Persson, B N J

    2015-05-21

    We study rubber friction for tire tread compounds on asphalt road surfaces. The road surface topographies are measured using a stylus instrument and atomic force microscopy, and the surface roughness power spectra are calculated. The rubber viscoelastic modulus mastercurves are obtained from dynamic mechanical analysis measurements and the large-strain effective modulus is obtained from strain sweep data. The rubber friction is measured at different temperatures and sliding velocities, and is compared to the calculated data obtained using the Persson contact mechanics theory. We conclude that in addition to the viscoelastic deformations of the rubber surface by the road asperities, there is an important contribution to the rubber friction from shear processes in the area of contact. The analysis shows that the latter contribution may arise from rubber molecules (or patches of rubber) undergoing bonding-stretching-debonding cycles as discussed in a classic paper by Schallamach. PMID:26001467

  19. Rubber friction on road surfaces: Experiment and theory for low sliding speeds

    SciTech Connect

    Lorenz, B.; Persson, B. N. J.; Oh, Y. R.; Nam, S. K.; Jeon, S. H.

    2015-05-21

    We study rubber friction for tire tread compounds on asphalt road surfaces. The road surface topographies are measured using a stylus instrument and atomic force microscopy, and the surface roughness power spectra are calculated. The rubber viscoelastic modulus mastercurves are obtained from dynamic mechanical analysis measurements and the large-strain effective modulus is obtained from strain sweep data. The rubber friction is measured at different temperatures and sliding velocities, and is compared to the calculated data obtained using the Persson contact mechanics theory. We conclude that in addition to the viscoelastic deformations of the rubber surface by the road asperities, there is an important contribution to the rubber friction from shear processes in the area of contact. The analysis shows that the latter contribution may arise from rubber molecules (or patches of rubber) undergoing bonding-stretching-debonding cycles as discussed in a classic paper by Schallamach.

  20. Rubber friction on road surfaces: Experiment and theory for low sliding speeds

    NASA Astrophysics Data System (ADS)

    Lorenz, B.; Oh, Y. R.; Nam, S. K.; Jeon, S. H.; Persson, B. N. J.

    2015-05-01

    We study rubber friction for tire tread compounds on asphalt road surfaces. The road surface topographies are measured using a stylus instrument and atomic force microscopy, and the surface roughness power spectra are calculated. The rubber viscoelastic modulus mastercurves are obtained from dynamic mechanical analysis measurements and the large-strain effective modulus is obtained from strain sweep data. The rubber friction is measured at different temperatures and sliding velocities, and is compared to the calculated data obtained using the Persson contact mechanics theory. We conclude that in addition to the viscoelastic deformations of the rubber surface by the road asperities, there is an important contribution to the rubber friction from shear processes in the area of contact. The analysis shows that the latter contribution may arise from rubber molecules (or patches of rubber) undergoing bonding-stretching-debonding cycles as discussed in a classic paper by Schallamach.

  1. Rubber friction and tire dynamics.

    PubMed

    Persson, B N J

    2011-01-12

    We propose a simple rubber friction law, which can be used, for example, in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (Persson 2006 J. Phys.: Condens. Matter 18 7789). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to accurately calculate μ-slip curves (and the self-aligning torque) for braking and cornering or combined motion (e.g. braking during cornering). We present numerical results which illustrate the theory. Simulations of anti-blocking system (ABS) braking are performed using two simple control algorithms. PMID:21406818

  2. Rubber friction and tire dynamics

    NASA Astrophysics Data System (ADS)

    Persson, B. N. J.

    2011-01-01

    We propose a simple rubber friction law, which can be used, for example, in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (Persson 2006 J. Phys.: Condens. Matter 18 7789). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to accurately calculate μ-slip curves (and the self-aligning torque) for braking and cornering or combined motion (e.g. braking during cornering). We present numerical results which illustrate the theory. Simulations of anti-blocking system (ABS) braking are performed using two simple control algorithms.

  3. Metallicity determinations for globular clusters through spectrophotometry of their integrated light

    NASA Astrophysics Data System (ADS)

    Brodie, J. P.; Hanes, D. A.

    1986-01-01

    Using an appropriately weighted combination of 16 indices of absorption line strength measured in low-dispersion spectra of the integrated light of globular clusters, metallicities Fe/H are determined for thirty-six clusters in the Galaxy. The results confirm the suggestion that Zinn's (1980) scale suffers a systematic error in the region of intermediate metallicity and support an explanation in which his metallicity-indicative Q39 index has been diluted by excess ultraviolet light in clusters with anomalously rich blue horizontal branches. The methods, which involve the measurement of spectral features arising from many species, produce estimates of metallicity which are insensitive to this problem. Good agreement is found with several recent studies, but a disagreement is noted for the most metal-rich clusters studied by Frogel, Cohen, and Persson (1983). Finally, a similar method with a modified calibration is used to determine metallicities for the nuclei of six galaxies.

  4. Preventing ultimate harm as the justification for biomoral modification.

    PubMed

    Murphy, Timothy F

    2015-06-01

    Most advocates of biogenetic modification hope to amplify existing human traits in humans in order to increase the value of such traits as intelligence and resistance to disease. These advocates defend such enhancements as beneficial for the affected parties. By contrast, some commentators recommend certain biogenetic modifications to serve social goals. As Ingmar Persson and Julian Savulescu see things, human moral psychology is deficient relative to the most important risks facing humanity as a whole, including the prospect of Ultimate Harm, the point at which worthwhile life is forever impossible on the planet. These risks can be mitigated, they say, by enhancing moral psychology in novel ways. Persson and Savulescu argue that some parents should modify the underlying biogenetics of their children's moral psychology, if such measures were safe and effective, but they admit these interventions may not decouple humanity from Ultimate Harm. Neither are these modifications the only options, they concede, for addressing risks to humanity. Even with these concessions, saving humanity from itself is a fairly poor reason to modify the moral psychology of children. In most ways, adults would be better candidates, morally speaking, for modifications of psychology. Even then, there is no direct link between morally enhanced human beings and the hoped-for effect of better protection from Ultimate Harm. Asserting a general duty of all to contribute to the avoidance of Ultimate Harm is a better moral strategy than intervening in the moral psychology of some, even though meeting that duty may involve substantial interference with the free exercise of one's interests. PMID:25186171

  5. Koronis asteroid dust within Antarctic ice

    NASA Astrophysics Data System (ADS)

    Genge, Matthew J.

    2008-09-01

    Here I report the first discovery of large numbers of ordinarychondrite-derived micro-meteorites (MMs) recovered fromAntarctic ice. Ordinary chondrite-derived MMs comprise70% coarse-grained igneous particles and are identified on thebasis of their distribution of petrologic types, accessory mineralogy,and minor element compositions, all of which are very similarto those of millimeter-sized igneous objects known as chondrules,from ordinary chondrites, and largely distinct from those ofother meteorite groups. The majority of ordinary chondrite-derivedMMs are unequilibrated materials; however, 15% are equilibrated,indicating parent body metamorphism, and have compositions consistentwith both H (high iron) and L (low iron) chondrites. The totalabundance of ordinary chondrite-derived MMs of ~18% issimilar to predictions by numerical calculations for the abundanceof dust generated by the recent breakup of the Karin group asteroidsof the Koronis asteroid family, suggesting that these asteroidsare the main source of the particles. These MMs represent thefirst to be associated with a known asteroid and imply thatthe Karin group progenitor asteroid was a rubble-pile asteroidthat sampled different depths within the original internallymetamorphosed Koronis parent body.

  6. Quantum scattering of neon from a nanotextured surface.

    PubMed

    Levi, A C; Huang, C; Allison, W; Maclaren, D A

    2009-06-01

    Phonon exchange is the usual cause of decoherence in atom-surface scattering. By including quantum effects in the treatment of Debye-Waller scattering, we show that phonon exchange becomes ineffective when the relevant phonon frequencies are high. The result explains the surprising observation of strong elastic scattering of Ne from a Cu(100) surface nanotextured with a c(2 × 2) Li adsorbate structure. We extend a previous model to describe the phonon spectra by an Einstein oscillator component with an admixture of a Debye spectrum. The Einstein oscillator represents the dominant, high frequency vibration of the adsorbate, normal to the surface, while the Debye spectrum represents the substrate contribution. Neon scattering is so slow that exciting the adsorbate mode has a low probability and is impossible if the incident energy is below the threshold. Thus, adsorbate vibrations are averaged out. A theoretical discussion and calculation shows that under such circumstances the vibrations of a light adsorbate do not contribute to the Debye-Waller effect, with the result that Ne scattering at thermal energies is quantum mechanical and largely elastic, explaining the high reflectivity and the diffraction peaks observed experimentally. PMID:21715773

  7. Vibrational Properties of Nanocrystals from the Debye Scattering Equation

    PubMed Central

    Scardi, P.; Gelisio, L.

    2016-01-01

    One hundred years after the original formulation by Petrus J.W. Debije (aka Peter Debye), the Debye Scattering Equation (DSE) is still the most accurate expression to model the diffraction pattern from nanoparticle systems. A major limitation in the original form of the DSE is that it refers to a static domain, so that including thermal disorder usually requires rescaling the equation by a Debye-Waller thermal factor. The last is taken from the traditional diffraction theory developed in Reciprocal Space (RS), which is opposed to the atomistic paradigm of the DSE, usually referred to as Direct Space (DS) approach. Besides being a hybrid of DS and RS expressions, rescaling the DSE by the Debye-Waller factor is an approximation which completely misses the contribution of Temperature Diffuse Scattering (TDS). The present work proposes a solution to include thermal effects coherently with the atomistic approach of the DSE. A deeper insight into the vibrational dynamics of nanostructured materials can be obtained with few changes with respect to the standard formulation of the DSE, providing information on the correlated displacement of vibrating atoms. PMID:26916341

  8. Order Parameters for Two-Dimensional Networks

    NASA Astrophysics Data System (ADS)

    Kaatz, Forrest; Bultheel, Adhemar; Egami, Takeshi

    2007-10-01

    We derive methods that explain how to quantify the amount of order in ``ordered'' and ``highly ordered'' porous arrays. Ordered arrays from bee honeycomb and several from the general field of nanoscience are compared. Accurate measures of the order in porous arrays are made using the discrete pair distribution function (PDF) and the Debye-Waller Factor (DWF) from 2-D discrete Fourier transforms calculated from the real-space data using MATLAB routines. An order parameter, OP3, is defined from the PDF to evaluate the total order in a given array such that an ideal network has the value of 1. When we compare PDFs of man-made arrays with that of our honeycomb we find OP3=0.399 for the honeycomb and OP3=0.572 for man's best hexagonal array. The DWF also scales with this order parameter with the least disorder from a computer-generated hexagonal array and the most disorder from a random array. An ideal hexagonal array normalizes a two-dimensional Fourier transform from which a Debye-Waller parameter is derived which describes the disorder in the arrays. An order parameter S, defined by the DWF, takes values from [0, 1] and for the analyzed man-made array is 0.90, while for the honeycomb it is 0.65. This presentation describes methods to quantify the order found in these arrays.

  9. Structural Physics of Bee Honeycomb

    NASA Astrophysics Data System (ADS)

    Kaatz, Forrest; Bultheel, Adhemar; Egami, Takeshi

    2008-03-01

    Honeybee combs have aroused interest in the ability of honeybees to form regular hexagonal geometric constructs since ancient times. Here we use a real space technique based on the pair distribution function (PDF) and radial distribution function (RDF), and a reciprocal space method utilizing the Debye-Waller Factor (DWF) to quantify the order for a range of honeycombs made by Apis mellifera. The PDFs and RDFs are fit with a series of Gaussian curves. We characterize the order in the honeycomb using a real space order parameter, OP3, to describe the order in the combs and a two-dimensional Fourier transform from which a Debye-Waller order parameter, u, is derived. Both OP3 and u take values from [0, 1] where the value one represents perfect order. The analyzed combs have values of OP3 from 0.33 to 0.60 and values of u from 0.83 to 0.98. RDF fits of honeycomb histograms show that naturally made comb can be crystalline in a 2D ordered structural sense, yet is more `liquid-like' than cells made on `foundation' wax. We show that with the assistance of man-made foundation wax, honeybees can manufacture highly ordered arrays of hexagonal cells.

  10. Vibrational properties of nanocrystals from the Debye Scattering Equation

    DOE PAGESBeta

    Scardi, P.; Gelisio, L.

    2016-02-26

    One hundred years after the original formulation by Petrus J.W. Debije (aka Peter Debye), the Debye Scattering Equation (DSE) is still the most accurate expression to model the diffraction pattern from nanoparticle systems. A major limitation in the original form of the DSE is that it refers to a static domain, so that including thermal disorder usually requires rescaling the equation by a Debye-Waller thermal factor. The last is taken from the traditional diffraction theory developed in Reciprocal Space (RS), which is opposed to the atomistic paradigm of the DSE, usually referred to as Direct Space (DS) approach. Besides beingmore » a hybrid of DS and RS expressions, rescaling the DSE by the Debye-Waller factor is an approximation which completely misses the contribution of Temperature Diffuse Scattering (TDS). The present work proposes a solution to include thermal effects coherently with the atomistic approach of the DSE. Here, a deeper insight into the vibrational dynamics of nanostructured materials can be obtained with few changes with respect to the standard formulation of the DSE, providing information on the correlated displacement of vibrating atoms.« less

  11. Local Structure and Vibrational Properties of alpha-Pu, alpha-U, and the alpha-U Charge Density Wave

    SciTech Connect

    Nelson, E J; Allen, P G; Blobaum, K M; Wall, M A; Booth, C H

    2004-08-10

    The local atomic environment and vibrational properties of atoms in monoclinic pure {alpha}-plutonium as well as orthorhombic pure {alpha}-uranium and its low-temperature charge-density-wave (CDW) modulation are examined by extended x-ray absorption fine structure spectroscopy (EXAFS). Pu L{sub III}-edge and U L{sub III}-edge EXAFS data measured at low temperatures verify the crystal structures of {alpha}-U and {alpha}-Pu samples previously determined by x-ray diffraction and neutron scattering. Debye-Waller factors from temperature-dependent EXAFS measurements are fit with a correlated Debye model. The observed Pu-Pu bond correlated Debye temperature of {theta}{sub cD}({alpha}-Pu) = 162 {+-} 5 K for the pure {alpha}-Pu phase agrees with our previous measurement of the correlated Debye temperature of the gallium-containing {alpha}'-Pu phase in a mixed phase 1.9 at% Ga-doped {alpha}'-Pu/{delta}-Pu alloy. The temperature dependence of the U-U nearest neighbor Debye-Waller factor exhibits a sharp discontinuity in slope near T{sub CDW} = 43 K, the transition temperature at which the charge-density wave (CDW) in {alpha}-U condenses from a soft phonon mode along the (100) direction. Our measurement of the CDW using EXAFS is the first observation of the structure of the CDW in polycrystalline {alpha}-U. The different temperature dependence of the Debye-Waller factor for T < T{sub CDW} can be modeled by the change in bond length distributions resulting from condensation of the charge density wave. For T > T{sub CDW}, the observed correlated Debye temperature of {theta}{sub cD}({alpha}-U) = 199 {+-} 3 K is in good agreement with other measurements of the Debye temperature for polycrystalline {alpha}-U. CDW structural models fit to the {alpha}-U EXAFS data support a squared CDW at the lowest temperatures, with a displacement amplitude of {var_epsilon} = 0.05 {+-} 0.02 {angstrom}.

  12. Local structure and vibrational properties of alpha-Pu, alpha-Uand the alpha-U charge density wave

    SciTech Connect

    Nelson, E.J.; Allen, P.G.; Blobaum, K.J.M.; Wall, W.A.; Booth, C.H.

    2004-08-10

    The local atomic environment and vibrational properties of atoms in monoclinic pure {alpha}-plutonium as well as orthorhombic pure a-uranium and its low-temperature charge-density-wave (CDW) modulation are examined by extended x-ray absorption fine structure spectroscopy (EXAFS). Pu L{sub III}-edge and U L{sub III}-edge EXAFS data measured at low temperatures verify the crystal structures of {alpha}-U and {alpha}-Pu samples previously determined by x-ray diffraction and neutron scattering. Debye-Waller factors from temperature-dependent EXAFS measurements are fit with a correlated Debye model. The observed Pu-Pu bond correlated Debye temperature of {theta}{sub cD}({alpha}-Pu) = 162 {+-} 5 K for the pure {alpha}-Pu phase agrees with our previous measurement of the correlated Debye temperature of the gallium-containing {alpha}{prime}-Pu phase in a mixed phase 1.9 at% Ga-doped {alpha}{prime}-Pu/{delta}-Pu alloy. The temperature dependence of the U-U nearest neighbor Debye-Waller factor exhibits a sharp discontinuity in slope near T{sub CDW} = 43 K, the transition temperature at which the charge-density wave (CDW) in {alpha}-U condenses from a soft phonon mode along the (100) direction. Our measurement of the CDW using EXAFS is the first observation of the structure of the CDW in polycrystalline {alpha}-U. The different temperature dependence of the Debye-Waller factor for T < T{sub CDW} can be modeled by the change in bond length distributions resulting from condensation of the charge density wave. For T > T{sub CDW}, the observed correlated Debye temperature of {theta}{sub cD}({alpha}-U) = 199 {+-} 3 K is in good agreement with other measurements of the Debye temperature for polycrystalline {alpha}-U. CDW structural models fit to the {alpha}-U EXAFS data support a squared CDW at the lowest temperatures, with a displacement amplitude of {var_epsilon} = 0.05 {+-} 0.02 {angstrom}.

  13. Persistent discourses in physics education: gender neutrality and the gendering of competence

    NASA Astrophysics Data System (ADS)

    Gonsalves, Allison

    2014-06-01

    In her article, Karin Due presents us with a contradiction in physics: the construction of physics as a symbolically masculine discipline alongside a simultaneous discourse of the "gender-neutrality" of the discipline. Due's article makes an important contribution to the study of the gendering of physics practices, particularly in group dynamics, and how this serves to simultaneously reinforce the two competing discourses of physics as a masculine discipline, and the discourse of physics as a gender neutral discipline. Due also suggests that an implication of this contradiction is a limited number of available positions for girls in physics compared to those available to boys. I wish to take up this observation and discuss how available positions for boys and girls in physics are related quite closely to two other concepts discussed in Due's article: competence and recognition.

  14. Perspectives on positioning, interaction, and learning in small-group discussion: possibilities for extending the analytic lens

    NASA Astrophysics Data System (ADS)

    Kittleson, Julie M.; Wilson, Rachel E.

    2014-06-01

    In this forum piece, we respond to Karin Due's study of social dynamics in groups of students in physics class and gender issues that play out in this context. We discuss two threads that appear in Due's paper: one pertains to patterns of talk within groups and how these patterns open up possibilities for learning, the other pertains to ways in which gender is constructed within groups and made visible via discourse. Our comments are intended to provide alternative ways of thinking about such issues. We hope to provide insight into how to deepen analyses of group dynamics and gender because research in both areas is important in terms of understanding how social contexts support and/or constrain learning, gender identity, and the like.

  15. Origin of the Near-Ecliptic Circumsolar Dust Band

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Bottke, William F.; Vokrouhlický, David; Sykes, Mark; Lien, David J.; Stansberry, John

    2008-06-01

    The zodiacal dust bands are bright infrared (IR) strips produced by thermal emission from circumsolar rings of particles. Two of the three principal dust bands, known as β and γ, were previously linked to the recent asteroid collisions that produced groups of fragments, so-called asteroid families, near the orbits of (832) Karin and (490) Veritas. The origin of the third, near-ecliptic α band has been unknown until now. Here we report the discovery of a recent breakup of a >20 km diameter asteroid near α's originally suspected source location in the Themis family. Numerical modeling and observations of the α-band thermal emission from the Spitzer Space Telescope indicate that the discovered breakup is the source of α-band particles. The recent formation of all principal dust bands implies a significant time variability of the circumstellar debris disks.

  16. Observations of Members of Very Young Asteroid Families

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.; Merline, W. J.; Nesvorny, D.; Tamblyn, P. M.; Young, E. F.

    2005-08-01

    Several asteroid families or clusters have been found [cf. D. Nesvorny et al. 2003, Ap.J. 591:486-497] to have very short dynamical ages. The Veritas family of C-type asteroids, Karin cluster within the S-type Koronis family, and the Iannini cluster (apparently S-type) formed about 8.3, 5.8, and <5 Myr ago, respectively. If one or more kinds of asteroidal processes (e.g. spin evolution, space weathering, devolatilization of near-surface materials, satellite formation and evolution) operate on timescales comparable with or slower than several Myr, then we may expect to observe different physical properties for members of these recently formed families than for older family members. During the first year of our multifaceted observing program, we have used numerous facilities (IRTF/MIRSI, IRTF/SPeX, HST, Spitzer, CTIO 0.9m, KPNO 0.9m and 2.1m, VLT AO, Gemini AO, and Keck AO), during 14 different runs, to obtain about 100 different observational datasets for members of the 3 young families plus numerous additional observations of controls (e.g. Themis family and non-Karin members of the Koronis family). Techniques employed include lightcurve photometry, visible colorimetry, near-IR spectral reflectance, thermal IR, and AO search for satellites. We discuss representative results from these observations. Theoretical synthesis of the data must await a more complete sampling of these family asteroids by the different techniques. This work is being supported primarily by the NASA Planetary Astronomy Program and by the observing facilities listed.

  17. Electrically Detected Magnetic Resonance (EDMR) of Defects in GaN Light Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Ishida, H.; Maeda, H.; Hirano, A.; Kubozono, Y.; Furukawa, Y.

    1997-02-01

    Local structures around Pb(II) and Sn(II) in CH3NH3PbX3 (X = Cl, Br, I) and CH3NH3SnX3 (X = Br, I) were studied by Pb LIII-edge and Sn K-edge EXAFS in the temperature range of 10 to 293 K. The M-X distances (M = Pb, Sn; X = Cl, Br, I), the coordination numbers, and the Debye-Waller factors were determined in three, four, three, five, and two solid phases of CH3NH3PbCl3, CH3NH3PbBr3, CH3NH3PbI3, CH3NH3SnBr3, and CH3NH3SnI3, respectively. Five kinds of deformed octahedra consisting of halogens were observed.

  18. An in-situ heater for the XAS beamline (12-ID) in Australia

    NASA Astrophysics Data System (ADS)

    Johannessen, B.; Hussain, Z. S.; East, D. R.; Gibson, M. A.

    2013-04-01

    To accommodate for a growing number of requests by our user community an in-situ heater has been commissioned for the X-ray absorption spectroscopy (XAS) beamline 12-ID at the Australian Synchrotron. Here, we present an in-situ method for calibrating the temperature of the heating stage based on an anharmonic, correlated Einstein model. Specifically, we show that a temperature-dependant study of a bulk metallic foil (7.5 μm Cu) can be used to accurately calibrate the temperature of the heater. We also present the temperature-dependant coordination number, bond length, Debye-Waller factor, and third order cumulant to the bond length distribution function of the material from 18K to 1074K. At the higher temperatures we find that the atomic structure is comparable to that of an amorphous or liquid material indicating a gradual transition from crystalline to disordered atomic structure.

  19. Diffraction studies of the thermal properties of nanocrystalline Pd and Cr

    SciTech Connect

    Eastman, J.A.; Thompson, L.J. ); Fitzsimmons, M.R.; Lawson, A.C.; Robinson, R.A. )

    1992-09-01

    Quantitative X-ray and neutron diffraction measurements were made on nanocrystalline and coarse-grained samples of Pd and Cr. For both materials, Debye-Waller parameter comparisons over a temperature range of approximately 20-300 K indicate that the nanocrystalline materials have increased static displacements of atoms from their equilibrium sites compared to coarse-grained material. No grain-size-correlated differences in thermal vibrational amplitude, lattice parameter, or thermal expansion coefficients were observed in either material. In contrast to earlier results on nanocrystalline Pd, significantly more non-peak intensity is observed from a nanocrystalline Cr sample than from a coarse-grained Cr sample. Impurities may account for the increased background intensity from nanocrystalline Cr. These results indicate that there is no significant grain boundary excess volume in nanocrystalline Pd, and therefore the reduced density typically observed in nanocrystalline Pd samples must be due to porosity.

  20. The origins of electrocardiography in Poland

    PubMed Central

    2015-01-01

    The progress of science and technology in the 19th century enabled better understanding of the electrical activity that occurs during a heartbeat. However, it was only the construction and introduction of the galvanometer that cleared the way for appropriate experimental and clinical studies. Marey, Waller, Wenckebach, Einthoven, and Pardee are just examples of the world's pioneers of electrocardiography. Polish researchers, including Cybulski, Eiger, Rzętkowski, Surzycki, and Latkowski, also contributed to the development of this area of study. The following article is a review aiming to reconstruct the origins of electrocardiography in Poland, both as a measurement method used in experiments and as a diagnostic tool in clinical studies conducted in the years preceding the outbreak of World War I. PMID:26336508

  1. Investigation on species distribution and EXAFS structure of aqueous rubidium pentaborate solutions

    NASA Astrophysics Data System (ADS)

    Miao, J. T.; Fang, C. H.; Fang, Y.; Zhu, F. Y.; Liu, H. Y.; Zhou, Y. Q.; Ge, H. W.; Sun, P. C.; Zhao, X. C.

    2016-04-01

    Based on the measured pH data and reported equilibrium constants, the main polyborate species formation existing in solution was investigated using the Newton iteration method at 298 and 333 K, and checked by the method of 11B nuclear magnetic resonance (NMR) spectroscopy. The neighboring structure of rubidium ion was studied at room temperature, which the structural parameters, including the coordination number, interatomic distance of Rb-O and Debye-Waller factor, were determined by the synchrotron radiation extended X-ray absorption fine structure (EXAFS). The results show that the average interatomic distance of Rb-O is 2.93 ± 0.004 Å and coordination number is 7.7 ± 0.9 in the first hydration shell around rubidium ion.

  2. Aqueous complexation of citrate with neodymium(III) and americium(III): a study by potentiometry, absorption spectrophotometry, microcalorimetry, and XAFS.

    PubMed

    Brown, M Alex; Kropf, A Jeremy; Paulenova, Alena; Gelis, Artem V

    2014-05-01

    The aqueous complexation of Nd(III) and Am(III) with anions of citrate was studied by potentiometry, absorption spectrophotometry, microcalorimetry, and X-ray absorption fine structure (XAFS). Using potentiometric titration data fitting the metal-ligand (L) complexes that were identified for Nd(III) were NdHL, NdL, NdHL2, and NdL2; a review of trivalent metal-citrate complexes is also included. Stability constants for these complexes were calculated from potentiometric and spectrophotometric titrations. Microcalorimetric results concluded that the entropy term of complex formation is much more dominant than the enthalpy. XAFS results showed a dependence in the Debye-Waller factor that indicated Nd(iii)-citrate complexation over the pH range of 1.56-6.12. PMID:24619154

  3. Vibrational dynamics and surface structure of Bi(111) from helium atom scattering measurements

    NASA Astrophysics Data System (ADS)

    Mayrhofer-Reinhartshuber, M.; Tamtögl, A.; Kraus, P.; Rieder, K. H.; Ernst, W. E.

    2012-03-01

    The Bi(111) surface was studied by elastic scattering of helium atoms at temperatures between 118 and 423 K. The observed diffraction patterns with clear peaks up to third order were used to model the surface corrugation using the eikonal approximation as well as the GR method. Best fit results were obtained with a rather large corrugation height compared to other surfaces with metallic character. The corrugation shows a slight enhancement of the surface electron density in between the positions of the surface atoms. The vibrational dynamics of Bi(111) were investigated by measurements of the Debye-Waller attenuation of the elastic diffraction peaks and a surface Debye temperature of (84 ± 8) K was determined. A decrease of the surface Debye temperature at higher temperatures that was recently observed on Bi nanofilms could not be confirmed in the case of our single-crystal measurements.

  4. Hydrologic data for urban studies in the Austin, Texas, metropolitan area, 1979

    USGS Publications Warehouse

    Slade, R.M.; Dorsey, M.E.; Gordon, J.D.; Mitchell, R.N.; Gaylord, J.L.

    1981-01-01

    This report contains rainfall and runoff data collected during the 1979 water year for the Austin, Texas, metropolitan area. In 1975, the program was expanded to include the collection of water-quality data. In 1978, the program was expanded to include a groundwater resources study of the south Austin metropolitan area in the Balcones fault zone. The information will be useful in determining the extent to which progressive urbanization will affect the yeild and mode of occurrence of storm runoff. The major streams in the study area are the Colorado River, Onion Creek, Barton Creek, Walnut Creek, Bull Creek, Boggy Creek, Shoal Creek, Williamson Creek, Slaughter Creek, Bear Creek, and Waller Creek. Detailed rainfall-runoff computations are presented for eight storm periods during the 1979 water year. Water-quality data for sites in the Austin metropolitan area are also given in this report. (USGS)

  5. Effects of Boron Addition to the Atomic Structure and Soft Magnetic Properties of FeCoB Films

    SciTech Connect

    Yang,A.; Imrane, H.; Lou, J.; Kirkland, J.; Vittoria, C.; Sun, N.; Harris, V.

    2008-01-01

    The magnetic, microwave, and the atomic structure properties of (Fe0.7Co0.3)1?xBx sputtered films on glass substrates were investigated. The addition of boron induced a decrease in coercivity and ferromagnetic resonance linewidth. The amorphous structure was formed at x ? 0.075. Extended x-ray absorption fine structure (EXAFS) of Fe and Co showed the reduced Fourier transform (FT) amplitude, and increased Debye-Waller factors as x was increased, indicating the increased disorder due to the thermal and structural displacements. Possible Fe-B bonding was observed with a reduced bond length, which indicates boron atoms' preference for staying in the interstitial sites in bcc unit cell.

  6. Fungible weights in logistic regression.

    PubMed

    Jones, Jeff A; Waller, Niels G

    2016-06-01

    In this article we develop methods for assessing parameter sensitivity in logistic regression models. To set the stage for this work, we first review Waller's (2008) equations for computing fungible weights in linear regression. Next, we describe 2 methods for computing fungible weights in logistic regression. To demonstrate the utility of these methods, we compute fungible logistic regression weights using data from the Centers for Disease Control and Prevention's (2010) Youth Risk Behavior Surveillance Survey, and we illustrate how these alternate weights can be used to evaluate parameter sensitivity. To make our work accessible to the research community, we provide R code (R Core Team, 2015) that will generate both kinds of fungible logistic regression weights. (PsycINFO Database Record PMID:26651981

  7. Local structure and superconductivity of the Ce1-xLaxRu2 Laves phase system

    NASA Astrophysics Data System (ADS)

    Saini, N. L.; Agrestini, S.; Amato, E.; Filippi, M.; di Castro, D.; Bianconi, A.; Manfrinetti, P.; Palenzona, A.; Marcelli, A.

    2004-09-01

    We have studied local structure of the Laves phase Ce1-xLaxRu2 superconductor by Ru K-edge extended x-ray absorption fine-structure measurements focusing on the small La concentration regime where the transition temperature Tc passes through a local maximum. We find that correlated Debye-Waller factor of the Ru-Ru bonds follows Tc with the varying La concentration in the system. Although, this remarkable Tc correlation on the local atomic structure suggests important role of the electron-lattice interactions, the band-structure effects seem more likely the reason to drive the anomalous superconducting behavior and the Tc maximum in this 4f system.

  8. Effects of boron addition to the atomic structure and soft magnetic properties of FeCoB films

    NASA Astrophysics Data System (ADS)

    Yang, Aria; Imrane, Hassan; Lou, Jing; Kirkland, Johnny; Vittoria, Carmine; Sun, Nian; Harris, Vincent G.

    2008-04-01

    The magnetic, microwave, and the atomic structure properties of (Fe0.7Co0.3)1-xBx sputtered films on glass substrates were investigated. The addition of boron induced a decrease in coercivity and ferromagnetic resonance linewidth. The amorphous structure was formed at x ˜0.075. Extended x-ray absorption fine structure (EXAFS) of Fe and Co showed the reduced Fourier transform (FT) amplitude, and increased Debye-Waller factors as x was increased, indicating the increased disorder due to the thermal and structural displacements. Possible Fe-B bonding was observed with a reduced bond length, which indicates boron atoms' preference for staying in the interstitial sites in bcc unit cell.

  9. LLE (Laboratory for Laser Energetics) review

    NASA Astrophysics Data System (ADS)

    Kumpan, S. A.

    This volume of the LLE Review, covering the period April to June 1990, contains articles in two main sections, Progress in Laser Fusion and Advanced Technology Developments. The first article presents the theoretical interpretation of the glass-ablator cryogenic-implosion experiments recently conducted on OMEGA. It is followed by an article describing the analysis of neutron time-of-flight data taken during DT and DD experiments; and a discussion of the improvements to laser diagnostics that now provide for precise control of the OMEGA laser is given. This paper contains a report on the development of transparent conductive coatings for KDP crystals, and a discussion of the study of the transient-surface Debye-Waller effect in materials irradiated with an ultrafast laser.

  10. Lattice Instability of 2H-TaSe2

    NASA Astrophysics Data System (ADS)

    John Bosco Balaguru, R.; Lawrence, N.; Alfred Cecil Raj, S.

    The charge density wave (CDW) in the layered compound 2H-TaSe2 at low temperatures has a commensurate phase, which causes super lattice points to appear in the Brillöuin zone of the undistorted phase. A Born-von Karman formalism has been employed for the calculation of phonon frequency distribution curves of 2H-TaSe2 both in the normal and in the commensurate charge density wave (CCDW) phases. A folding technique has been adopted for the calculation in the CCDW phase. The phonon distribution for both the phases have been reported. With these distributions the thermal properties such as specific heat capacity, Debye Waller factor W(k) and thermal conductivity have been worked out, and compared with the available experimental results.

  11. Influence of the chemical nature of implanted ions on the structure of a silicon layer damaged by implantation

    SciTech Connect

    Shcherbachev, K. D. Voronova, M. I.; Bublik, V. T.; Mordkovich, V. N. Pazhin, D. M.; Zinenko, V. I.; Agafonov, Yu. A.

    2013-12-15

    The influence of the implantation of silicon single crystals by fluorine, nitrogen, oxygen, and neon ions on the distribution of strain and the static Debye-Waller factor in the crystal lattice over the implanted-layer depth has been investigated by high-resolution X-ray diffraction. The density depth distribution in the surface layer of native oxide has been measured by X-ray reflectometry. Room-temperature implantation conditions have ensured the equality of the suggested ranges of ions of different masses and the energies transferred by them to the target. It is convincingly shown that the change in the structural parameters of the radiation-damaged silicon layer and the native oxide layer depend on the chemical activity of the implanted ions.

  12. Structure refinement of sub-cubic-mm volume sample at high pressures by pulsed neutron powder diffraction: application to brucite in an opposed anvil cell

    NASA Astrophysics Data System (ADS)

    Okuchi, Takuo; Tomioka, Naotaka; Purevjav, Narangoo; Abe, Jun; Harjo, Stefanus; Gong, Wu

    2014-04-01

    Neutron powder diffraction measurements of 0.9 mm3 of mixture of deuterated brucite and pressure medium were conducted at pressures to 2.8 GPa, using an opposed anvil cell and a medium-resolution diffractometer at Japan Proton Accelerator Research Complex pulsed neutron source. Spurious-free diffraction patterns were successfully obtained and refined to provide all structural parameters including Debye-Waller factors. Tilting of hydroxyl dipoles of brucite toward one of the three nearest-neighbor oxygen anions was confirmed to be substantial at pressure as low as 1.5 GPa. By this application, technical feasibility to analyze such a small sample has been newly established, which would be useful to extend the applications of neutron diffraction at high pressures.

  13. Molecular dynamics of an α-helical polypeptide: Temperature dependence and deviation from harmonic behavior

    PubMed Central

    Levy, Ronald M.; Perahia, David; Karplus, Martin

    1982-01-01

    The mean square amplitudes of atomic fluctuations for a polypeptide (decaglycine) α-helix evaluated from molecular dynamics simulations at seven temperatures between 5 and 300 K are compared with analytic harmonic results and with experimental values. Above 100 K the harmonic approximation significantly underestimates the amplitudes of the displacements. Analysis of the time dependence of the fluctuations shows that low-frequency modes (<75 cm-1) dominate the atomic fluctuations and that there is a contribution with a very long relaxation time (>10 ps). Quantum corrections to the amplitude of the fluctuations are found to be small above 50 K. The mean square amplitudes obtained from the molecular dynamics simulations are compared with the values derived from x-ray temperature (Debye-Waller) factors for metmyoglobin (80, 250, and 300 K) and ferrocytochrome c (300 K). PMID:16593164

  14. The origins of electrocardiography in Poland.

    PubMed

    Gryglewski, Ryszard W

    2015-06-01

    The progress of science and technology in the 19(th) century enabled better understanding of the electrical activity that occurs during a heartbeat. However, it was only the construction and introduction of the galvanometer that cleared the way for appropriate experimental and clinical studies. Marey, Waller, Wenckebach, Einthoven, and Pardee are just examples of the world's pioneers of electrocardiography. Polish researchers, including Cybulski, Eiger, Rzętkowski, Surzycki, and Latkowski, also contributed to the development of this area of study. The following article is a review aiming to reconstruct the origins of electrocardiography in Poland, both as a measurement method used in experiments and as a diagnostic tool in clinical studies conducted in the years preceding the outbreak of World War I. PMID:26336508

  15. Resuscitation great. Willem Einthoven: the development of the human electrocardiogram.

    PubMed

    Cajavilca, Christian; Varon, Joseph

    2008-03-01

    The electrocardiogram is one of the most commonly used diagnostic tools in healthcare. This ingenious device was developed and created in the early 1900s by Willem Einthoven, MD, PhD after studying the mechanisms of electromagnetism and Waller's capillary electrometer. Einthoven dedicated most of his research and clinical activities to improve the early versions of the electrical current recording medical devices. Einthoven's most notable invention was the string galvanometer which we now know as the electrocardiogram. Although the idea of using the string galvanometer as a diagnostic tool faced opposition by scientists and physicians of his time, he remained convinced of the potential of his machine to improve patient care. Einthoven's string galvanometer subsequently became the standard diagnostic tool for recognition and differentiation of heart conditions through the interpretation of cardiac waves, and has become standard practice in the field of resuscitation. In 1924, Einthoven received the Nobel Prize in Medicine for his development of the string galvanometer. PMID:18164799

  16. Willem Einthoven--inventor of electrocardiography.

    PubMed

    Schweitzer, P; Keller, S

    2002-12-01

    Willem Einthoven, the inventor of the string galvanometer electrocardiograph, was born in the Dutch East Indies, studied medicine in Utrecht Holland, and became chairman of the Department of Physiology at the University of Leiden. In 1924 he was awarded the Nobel Price for physiology and medicine. Einthoven became interested in electrophysiology after Waller's demonstration of the human electrogram using Lippmann's capillary electrometer. Because of important limitations of this device, Einthoven decided to construct the string galvanometer to be used for physiological research and in clinical medicine. Einthoven's main achievements in electrophysiology were the description of the normal ECG, some physiological effects on the ECG, the three ECG leads and the triangle rule. In 1906 in cooperation with the university hospital, Einthoven demonstrated the clinical usefulness of the electrocardiograph. PMID:12744012

  17. Approximate changes in water levels in wells completed in the Chicot and Evangeline aquifers, 1977-93 and 1992-93, and measured compaction, 1973-92, in the Houston-Galveston region, Texas

    USGS Publications Warehouse

    Kasmarek, Mark C.; Coplin, L.S.; Campodonico, Al

    1993-01-01

    This report is one in a series of reports that depict water-level changes since 1977 and compaction of subsurface material since 1973.  The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District and the City of Houston, and presents maps showing the approximate changes in water levels in wells completed in the Chicot and Evangeline aquifers, 1977-93 and 1992-93 (figs. 1-4), and measured compaction, 1973-92 (figs. 5 and 6), in the Houston-Galveston region.  The Houston-Galveston region includes Harris and Galveston Counties and adjacent parts of Brazoria, Fort Bend, Waller, Montgomery, Liberty, and Chambers Counties.

  18. Approximate changes in water levels in wells completed in the Chicot and Evangeline aquifers, 1977-94 and 1993-94, and measured compaction, 1973-93, in the Houston-Galveston region, Texas

    USGS Publications Warehouse

    Kasmarek, Mark C.; Coplin, L.S.; Santos, Horacio X.

    1994-01-01

    This report is one in a series of reports that depict water-level changes since 1977 and compaction of subsurface material since 1973.  The report was prepared in cooperation with the City of Houston and the Harris-Galveston Coastal Subsidence District, and presents maps showing the approximate changes in water levels in wells completed in the Chicot and Evangeline aquifers, 1977-94 and 1993-94 (figs. 1-4), extensometer site locations (fig. 5), and measured compaction, 1973-93 (fig. 6), in the Houston-Galveston region.  Water-level change maps were prepared previously by Kasmarek and others (1993).  The Houston-galveston region includes Harris and Galveston Counties and adjacent parts of Brazoria, Fort Bend, Waller, Montgomery, Liberty, and Chambers Counties.

  19. Approximate changes in water levels in wells completed in the Chicot and Evangeline aquifers, 1977-92 and 1991-92, and measured compaction, 1973-91 in the Houston-Galveston region, Texas.

    USGS Publications Warehouse

    Kasmarek, Mark C.; Barbie, Dana L.; Campodonico, Al

    1992-01-01

    This report is one in a series of reports that depict water-level changes since 1977 and compaction of subsurface material since 1973.  The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District and the City of Houston, and presents maps showing the approximate changes in water-levels in wells completed in the Chicot and Evangeline aquifers, 1977-92 and 1991-92 (figs. 1-4), and measured compations, 1973-91 (figs. 5 and 6), in the Houston-Galveston region.  The Houston-Galveston region includes Harris and Galveston Counties and adjacent parts of Brazoria, Fort Bend, Waller, Montgomery, Liberty, and Chambers Counties.

  20. A survey of global radiation damage to 15 different protein crystal types at room temperature: a new decay model

    PubMed Central

    Leal, Ricardo Miguel Ferraz; Bourenkov, Gleb; Russi, Silvia; Popov, Alexander N.

    2013-01-01

    The radiation damage rates to crystals of 15 model macromolecular structures were studied using an automated radiation sensitivity characterization procedure. The diffracted intensity variation with dose is described by a two-parameter model. This model includes a strong resolution-independent decay specific to room-temperature measurements along with a linear increase in overall Debye–Waller factors. An equivalent representation of sensitivity via a single parameter, normalized half-dose, is introduced. This parameter varies by an order of magnitude between the different structures studied. The data show a correlation of crystal radiation sensitivity with crystal solvent content but no dose-rate dependency was detected in the range 0.05–300 kGy s−1. The results of the crystal characterization are suitable for either optimal planning of room-temperature data collection or in situ crystallization plate screening experiments. PMID:23254652

  1. LLE (Laboratory for Laser Energetics) review

    SciTech Connect

    Kumpan, S.A.

    1990-01-01

    This volume of the LLE Review, covering the period April--June 1990, contains articles in two main sections, Progress in Laser Fusion and Advanced Technology Developments. The first article presents the theoretical interpretation of the glass-ablator cryogenic-implosion experiments recently conducted on OMEGA. It is followed by an article describing the analysis of neutron time-of-flight data taken during DT and DD experiments; and a discussion of the improvements to laser diagnostics that now provide for precise control of the OMEGA laser is given. This paper contains a report on the development of transparent conductive coatings for KDP crystals, and a discussion of the study of the transient-surface Debye-Waller effect in materials irradiated with an ultrafast laser.

  2. Vibron Solitons and Soliton-Induced Infrared Spectra of Crystalline Acetanilide

    NASA Astrophysics Data System (ADS)

    Takeno, S.

    1986-01-01

    Red-shifted infrared spectra at low temperatures of amide I (C=O stretching) vibrations of crystalline acetanilide measured by Careri et al. are shown to be due to vibron solitons, which are nonlinearity-induced localized modes of vibrons arising from their nonlinear interactions with optic-type phonons. A nonlinear eigenvalue equation giving the eigenfrequency of stationary solitons is solved approximately by introducing lattice Green's functions, and the obtained result is in good agreement with the experimental result. Inclusion of interactions with acoustic phonons yields the Debye-Waller factor in the zero-phonon line spectrum of vibron solitons, in a manner analogous to the case of impurity-induced localized harmonic phonon modes in alkali halides.

  3. Stochastic model for protein flexibility analysis

    NASA Astrophysics Data System (ADS)

    Xia, Kelin; Wei, Guo-Wei

    2013-12-01

    Protein flexibility is an intrinsic property and plays a fundamental role in protein functions. Computational analysis of protein flexibility is crucial to protein function prediction, macromolecular flexible docking, and rational drug design. Most current approaches for protein flexibility analysis are based on Hamiltonian mechanics. We introduce a stochastic model to study protein flexibility. The essential idea is to analyze the free induction decay of a perturbed protein structural probability, which satisfies the master equation. The transition probability matrix is constructed by using probability density estimators including monotonically decreasing radial basis functions. We show that the proposed stochastic model gives rise to some of the best predictions of Debye-Waller factors or B factors for three sets of protein data introduced in the literature.

  4. Molecular environment of Ni after its use for removal of CMP nanoparticle

    NASA Astrophysics Data System (ADS)

    Wei, Y.-L.; Chen, K.-W.; Peng, Y.-S.; Paul Wang, H.

    2010-07-01

    X-ray absorption spectroscopy (XAS) is employed to investigate the molecular environment around nickel that, in the form of nickel sulfate solution, has been added to precipitate nanoparticles in chemical mechanical polishing (CMP) waste water. After phase separation, for the liquid-phase sample, both the white line intensity in the normalized Ni K-edge X-ray absorption near edge structure (XANES) spectrum and the amplitude of the extended X-ray absorption fine structure (EXAFS) spectrum are enhanced due to the presence of solvation of water molecules, as compared to the solid-phase sample. Meanwhile, with the presence of water molecules, the coordination number increases; yet the Debye-Waller factor slightly decreases. The lack of chemical reduction of Ni 2+ in the CMP solution is suggested as the main reason why the charge neutralization precipitation method through the use of Ni 2+ is less effective than the system using Cu 2+ to precipitate nanoparticles as previously reported.

  5. Cross-cultural generalizability of personality dimensions: relating indigenous and imported dimensions in two cultures.

    PubMed

    Katigbak, M S; Church, A T; Akamine, T X

    1996-01-01

    The cross-cultural generalizability of personality dimensions was investigated by (a) identifying indigenous Philippine dimensions, (b) testing the cross-cultural replicability of the NEO 5-factor model (P. T. Costa & R.R. McCrae, 1992), and (c) relating Philippine and Western dimensions in Philippine and U.S. samples of college students. Filipino self-ratings (N = 536) on indigenous items were factor analyzed, and 6 Philippine dimensions were obtained. Conclusions about the replicability of the 5-factor model in the Philippines (N = 432) depended on whether exploratory, Procrustes, or confirmatory factor methods were used. In regression and joint factor analyses, moderate to strong associations were found between the Philippine dimensions and (a) dimensions from the 5-factor model in both Philippine (N = 387) and U.S. (N = 610) samples, and (b) the Tellegen model (A. Tellegen, 1985; A. Tellegen & N.G. Waller, in press) in a U.S. sample (N = 603). PMID:8558409

  6. Experimental signatures of a nonequilibrium phase transition governing the yielding of a soft glass

    NASA Astrophysics Data System (ADS)

    Hima Nagamanasa, K.; Gokhale, Shreyas; Sood, A. K.; Ganapathy, Rajesh

    2014-06-01

    We present direct experimental signatures of a nonequilibrium phase transition associated with the yield point of a prototypical soft solid—a binary colloidal glass. By simultaneously quantifying single-particle dynamics and bulk mechanical response, we identified the threshold for the onset of irreversibility with the yield strain. We extracted the relaxation time from the transient behavior of the loss modulus and found that it diverges in the vicinity of the yield strain. This critical slowing down is accompanied by a growing correlation length associated with the size of regions of high Debye-Waller factor, which are precursors to yield events in glasses. Our results affirm that the paradigm of nonequilibrium critical phenomena is instrumental in achieving a holistic understanding of yielding in soft solids.

  7. Xafs Studies of Transition Metal And Halogen Biomaterials in Invertebrate Tools

    SciTech Connect

    Tao, Y.; Shokes, J.E.; Scott, R.A.; Nesson, M.H.; Schofield, R.M.S.

    2009-06-04

    A significant fraction of arthropods, as well as some worms and members of other phyla, contain extraordinary amounts of transition metals (Mn, Fe, Cu, Zn) and halogens (Cl, Br, I) in their hardened tools (jaws, claws, fangs, stings, etc.). Bulk Zn EXAFS differs for different kinds of tools, whereas Br appears to occupy a common environment in different tools. Zn binding to histidine is observed for most samples but bulk Zn EXAFS is likely to sample a mixture of Zn coordination environments. Principal Component Analysis (PCA) suggests the presence of three main Zn coordination components. The similar Br EXAFS in widely different tools indicates that Br-phenyl is the dominant form, suggesting the presence of brominated aromatic amino acid-derived organic components in these biomaterials. Calculated Debye-Waller factors are used to simulate EXAFS when model compound data are unavailable.

  8. Non invasive measurement of strain and temperature by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Holden, T. M.; Root, J. H.; Tennant, D. C.; Kroeze, D. E.; Leggett, D.

    1990-06-01

    Two methods have been developed to determine temperature noninvasively within engineering components by neutron diffraction. The integrated intensity of a diffraction line depends on temperature through the Debye-Waller factor. The angular position of the line, in the absence of an applied load, depends on temperature through the thermal expansion coefficient. Temperature may thus be determined by accurate relative intensity measurements with respect to a reference temperature and, alternatively, by accurate measurement of the interplanar spacings. It was also shown to be feasible to measure the strain response to an applied load at elevated temperatures. Measurements were made on Waspalloy and the Ti alloy AMS 4928. For Waspalloy, the thermal expansion at zero stress gave the average temperature with a precision of +/- 4 K and agreed with thermocouple measurements to within 5 K on average. The intensity data suggest that temperature can be measured with a precision of +/- 10 K in a loaded component.

  9. Refinement of protein dynamic structure: normal mode refinement.

    PubMed Central

    Kidera, A; Go, N

    1990-01-01

    An x-ray crystallographic refinement method, referred to as the normal mode refinement, is proposed. The Debye-Waller factor is expanded in terms of the effective normal modes whose amplitudes and eigenvectors are experimentally determined by the crystallographic refinement. In contrast to the conventional method, the atomic motions are treated generally as anisotropic and concerted. This method is assessed by using the simulated x-ray data given by a Monte Carlo simulation of human lysozyme. In this article, we refine the dynamic structure by fixing the average static structure to exact coordinates. It is found that the normal mode refinement, using a smaller number of variables, gives a better R factor and more information on the dynamics (anisotropy and collectivity in the motion). Images PMID:2339115

  10. Aggregate sound velocities and acoustic Grüneisen parameter of iron up to 300 GPa and 1,200 K

    PubMed Central

    Dubrovinsky, L. S.; Dubrovinskaia, N. A.; Le Bihan, T.

    2001-01-01

    Successful interpretation of available geophysical data requires experimental and theoretical information on the elasticity of solids under physical conditions of Earth's interior. Because iron is considered as major component in Earth's core, elastic properties of iron at high pressures and temperatures are very important for modeling its composition and dynamics. We use in situ x-ray diffraction data on ɛ-iron at static pressures up to 300 GPa and temperatures to 1,200 K to determine the Debye–Waller temperature factors and calculate aggregate sound velocities and Grüneisen parameter of ɛ-iron by using an approach that is based on Rietveld refinement at high pressures and temperatures. PMID:11504937

  11. Evidence of local structural order and spin-lattice coupling in the frustrated pyrochlore Y2Ru2O7

    NASA Astrophysics Data System (ADS)

    Castellano, C.; Berti, G.; Sanna, S.; Ruiz-Bustos, R.; van Duijn, J.; Brambilla, A.; Muñoz-Noval, Á.; Carretta, P.; Duò, L.; Demartin, F.

    2015-06-01

    We present an extended x-ray absorption fine structure study of the pyrochlore Y2Ru2O7 (8-298 K). We find evidence, on a local scale, of a significant magnetoelastic coupling at the Néel temperature TN˜77 K pointed out by a huge Debye-Waller σ2 factor deviation from a correlated temperature dependent Debye-like local order behavior plus a temperature independent static contribution. Moreover, we notice the occurrence of a potential local order-disorder structural phase transition at T*=150 K. This anomalous behavior is consistent with the pyrochlore's predisposition towards structural disorder and with a strong spin-phonon correlation. Remarkably the low-temperature order competes with the tendency of magnetic frustration to induce a less symmetric local structure.

  12. Sourcing and Communicating Cosmic Narratives -- A Role for the IAU?

    NASA Astrophysics Data System (ADS)

    Waller, William Howard

    2015-08-01

    Communicating astronomy critically depends on crafting competent and engaging stories. IAU Commission 55 has an opportunity to take the lead in exploring and celebrating astronomical narratives. Possibilities include an online "Astro Tales" publication of astronomical stories by IAU members for the general public (that complements the trade-oriented CAP), "Profiles in Astronomy" that feature interviews with IAU members, forums featuring exceptional science communicators and their cosmic stories, writing competitions for students, and an awards program. Through some version of these endeavors, the IAU could become a major arbiter of astronomical information and outreach worldwide. In this session, Dr. Waller will use his online journal "The Galactic Inquirer" at http://galacticinquirer.net as an exemplar and encourage input from participants.

  13. The influence of social anxiety on the body checking behaviors of female college students.

    PubMed

    White, Emily K; Warren, Cortney S

    2014-09-01

    Social anxiety and eating pathology frequently co-occur. However, there is limited research examining the relationship between anxiety and body checking, aside from one study in which social physique anxiety partially mediated the relationship between body checking cognitions and body checking behavior (Haase, Mountford, & Waller, 2007). In an independent sample of 567 college women, we tested the fit of Haase and colleagues' foundational model but did not find evidence of mediation. Thus we tested the fit of an expanded path model that included eating pathology and clinical impairment. In the best-fitting path model (CFI=.991; RMSEA=.083) eating pathology and social physique anxiety positively predicted body checking, and body checking positively predicted clinical impairment. Therefore, women who endorse social physique anxiety may be more likely to engage in body checking behaviors and experience impaired psychosocial functioning. PMID:25123084

  14. Dynamics and kinetics of monolayer CH4 on MgO(001) studied by helium-atom scattering

    NASA Astrophysics Data System (ADS)

    Jung, David R.; Cui, Jinhe; Frankl, Daniel R.

    1991-05-01

    The structure, vibrational excitations, and adsorption and desorption kinetics of monolayer CH4 on MgO have been investigated using several techniques of helium scattering. Structural information is presented in the form of high-order diffraction-peak intensities. A vibrational excitation of 7.5 meV measured by time-of-flight methods shows no dispersion. This excitation energy is used in an analysis of the Debye-Waller effect for the [00] and [1¯0] beams. Studies of adsorption and desorption rates exploiting the He-methane diffuse-scattering cross section indicate an island-growth mode and allow determination of the desorption activation energy. Differences between the low-coverage adsorption rates for adsorption on fresh versus previously exposed surfaces suggest that higher-binding-energy sites are present after the desorption of a methane monolayer.

  15. Psychopathic, not psychopath: taxometric evidence for the dimensional structure of psychopathy.

    PubMed

    Edens, John F; Marcus, David K; Lilienfeld, Scott O; Poythress, Norman G

    2006-02-01

    Although psychopathy is frequently regarded as qualitatively distinct from other conditions, relatively little research has examined whether psychopaths represent a distinct class of individuals. Using a sample of 876 prison inmates and court-ordered substance abuse patients who were administered the Psychopathy Checklist-Revised (R. D. Hare, 2003), the authors examined the latent structure of psychopathy using several taxometric procedures developed by Meehl and colleagues (P. E. Meehl & L. J. Yonce, 1994; N. G. Waller & P. E. Meehl, 1998). The results across these procedures offer no compelling support for the contention that psychopathy is a taxonic construct and contradict previous reports that psychopathy is underpinned by a latent taxon. The authors discuss the theoretical, public policy, and practice-level implications of these findings. PMID:16492104

  16. Equilibrium and structural studies on metal complexes of carbohyrates and their derivatives.

    PubMed

    Nagy, L; Szorcsik, A

    2002-04-10

    A summary is presented of the studies of our group on metal complexes of carbohydrates (aldoses, ketoses, mono-, di- and polysaccharides) and their derivatives (aldonic, alduronic acids, polyalcohols, amino sugars, amino acid sugar adducts, AMP, ATP, etc.). The results are reported of equilibrium, electrochemical, solution and solid-state structural studies of complexes of transition metals [Cu(II), Fe(III), Ni(II), Zn(II), Co(II), Ag(I), Mn in different oxidation states and organotin(IV)]. The structural parameters (coordination number, bond distance, and Debye-Waller factor) obtained by extended X-ray absorption fine structure spectroscopic (EXAFS) spectroscopy are discussed in detail. The general rules concerning the formation and structure of such complexes are emphasized. PMID:11931957

  17. Shear-deformation-potential constant of the conduction-band minima of Si: Pseudopotential calculations

    NASA Astrophysics Data System (ADS)

    Li, Ming-Fu; Gu, Zong-Quan; Wang, Jian-Qing

    1990-09-01

    We have calculated the value of the shear-deformation-potential constant Ξu of the conduction-band minima of Si and its temperature coefficient dΞu/dT. The value of Ξu is 9.0 eV for an ab initio pseudopotential calculation and 10.8 eV by the empirical-pseudopotential method (EPM), in good agreement with our experiment. The EPM calculations of the temperature dependence of Ξu yield the values of (dΞu/dT)||DW=-0.04 meV/K due to the Debye-Waller contribution, and (dΞu/dT)||TE=-0.04 meV/K for thermal expansion. We suspect and suggest that the existing experimental value of dΞu/dT~=+3 meV/K is unreliable due to large experimental uncertainty.

  18. EXAFS and X-ray diffraction study of LaCoO3 across the spin-state transition

    NASA Astrophysics Data System (ADS)

    Sikolenko, V. V.; Troyanchuk, I. O.; Efimov, V. V.; Efimova, E. A.; Tiutiunnikov, S. I.; Karpinsky, D. V.; Pascarelli, S.; Zaharko, O.; Ignatov, A.; Aquilanti, D.; Selutin, A. G.; Shmakov, A. N.; Prabhakaran, D.

    2016-05-01

    A combined high-resolution Co K-edge extended x-ray absorption fine structure (EXAFS) and high-resolution X-ray powder diffraction (XRD) study has been performed to clarify the detail of anomalous behavior of temperature-dependent magnetic susceptibility curve on the LaCoO3 across the spin-state (∼120 K) transition. According to XRD analysis, the Debye-Waller factor of Co-O bond exhibit rapid growth below 20 K whereas the temperature dependence of the average Co-O bond length shows linear behavior from 10 K to 400 K. The EXAFS data show an anomalous decrease of the Co-O bond lengths with respect to those obtained by XRD. No local distortion of CoO6 octahedral as temperature increases up to 400 K has been detected.

  19. Local environment of metal ions in phthalocyanines: K-edge X-ray absorption spectra.

    PubMed

    Rossi, G; d'Acapito, F; Amidani, L; Boscherini, F; Pedio, M

    2016-09-14

    We report a detailed study of the K-edge X-ray absorption spectra of four transition metal phthalocyanines (MPc, M = Fe, Co, Cu and Zn). We identify the important single and multiple scattering contributions to the spectra in the extended energy range and provide a robust treatment of thermal damping; thus, a generally applicable model for the interpretation of X-ray absorption fine structure spectra is proposed. Consistent variations of bond lengths and Debye Waller factors are found as a function of atomic number of the metal ion, indicating a variation of the metal-ligand bond strength which correlates with the spatial arrangement and occupation of molecular orbitals. We also provide an interpretation of the near edge spectral features in the framework of a full potential real space multiple scattering approach and provide a connection to the local electronic structure. PMID:27510989

  20. Zinc cysteine active sites of metalloproteins: A density functional theory and x-ray absorption fine structure study

    NASA Astrophysics Data System (ADS)

    Dimakis, Nicholas; Farooqi, Mohammed Junaid; Garza, Emily Sofia; Bunker, Grant

    2008-03-01

    Density functional theory (DFT) and x-ray absorption fine structure (XAFS) spectroscopy are complementary tools for the biophysical study of active sites in metalloproteins. DFT is used to compute XAFS multiple scattering Debye Waller factors, which are then employed in genetic algorithm-based fitting process to obtain a global fit to the XAFS in the space of fitting parameters. Zn-Cys sites, which serve important functions as transcriptional switches in Zn finger proteins and matrix metalloproteinases, previously have proven intractable by this method; here these limitations are removed. In this work we evaluate optimal DFT nonlocal functionals and basis sets for determining optimal geometries and vibrational densities of states of mixed ligation Zn(His)4-n(Cys)n sites. Theoretical results are compared to experimental XAFS measurements and Raman spectra from the literature and tabulated for use.

  1. Molecular Dynamics of an α -helical Polypeptide: Temperature Dependence and Deviation from Harmonic Behavior

    NASA Astrophysics Data System (ADS)

    Levy, Ronald M.; Perahia, David; Karplus, Martin

    1982-02-01

    The mean square amplitudes of atomic fluctuations for a polypeptide (decaglycine) α -helix evaluated from molecular dynamics simulations at seven temperatures between 5 and 300 K are compared with analytic harmonic results and with experimental values. Above 100 K the harmonic approximation significantly underestimates the amplitudes of the displacements. Analysis of the time dependence of the fluctuations shows that low-frequency modes (<75 cm-1) dominate the atomic fluctuations and that there is a contribution with a very long relaxation time (>10ps). Quantum corrections to the amplitude of the fluctuations are found to be small above 50 K. The mean square amplitudes obtained from the molecular dynamics simulations are compared with the values derived from x-ray temperature (Debye-Waller) factors for metmyoglobin (80, 250, and 300 K) and ferrocytochrome c (300 K).

  2. Is co-ruminating with friends related to health problems in victimized adolescents?

    PubMed

    Guarneri-White, Maria E; Jensen-Campbell, Lauri A; Knack, Jennifer M

    2015-02-01

    Co-rumination, or the tendency to revisit and endlessly discuss problems and negative events, has been linked to depression and other emotional difficulties (Rose, Carson, & Waller, 2007). The current study examined the moderating effect of co-rumination on the relationship between peer victimization and depression, anxiety, PTSD symptoms, and health problems in 108 adolescents aged 10-15 years. Adolescents and a parent completed measures of adolescents' peer victimization, co-rumination, depression, and health problems. Results indicate that adolescents who are both peer victimized and engaged in high levels of co-rumination were at highest risk for psychological problems. Co-rumination also moderated the relationship between peer victimization and physical health problems via general depressive symptoms (i.e., moderated mediation). PMID:25544426

  3. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation

    SciTech Connect

    Kopaska-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D.; Hall, D.R.

    1992-06-01

    This volume contains maps, well logging, structural cross section, graph of production history, porosity vs. natural log permeability plots, detailed core log, paragenetic sequence, and reservoir characterization sheet for the following fields in southwest Alabama: North Smiths Church oil field; North Wallers Creek oil field; Northeast Barnett oil field; Northwest Range oil field; Pace Creek oil field; Palmers Crossroads oil field; Perdido oil field; Puss Cuss Creek oil field; Red Creek gas condensate field; Robinson Creek oil field; Silas oil field; Sizemore Creek gas condensate field; Smiths Church gas condensate field; South Burnt Corn Creek oil field; South Cold Creek oil field; South Vocation oil field; South Wild Fork Creek gas condensate field; South Womack Hill oil field; Southeast Chatom gas condensate field; Southwest Barrytown oil field; and Souwilpa Creek gas condensate field.

  4. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. Appendix 1, Volume 3

    SciTech Connect

    Kopaska-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D.; Hall, D.R.

    1992-06-01

    This volume contains maps, well logging, structural cross section, graph of production history, porosity vs. natural log permeability plots, detailed core log, paragenetic sequence, and reservoir characterization sheet for the following fields in southwest Alabama: North Smiths Church oil field; North Wallers Creek oil field; Northeast Barnett oil field; Northwest Range oil field; Pace Creek oil field; Palmers Crossroads oil field; Perdido oil field; Puss Cuss Creek oil field; Red Creek gas condensate field; Robinson Creek oil field; Silas oil field; Sizemore Creek gas condensate field; Smiths Church gas condensate field; South Burnt Corn Creek oil field; South Cold Creek oil field; South Vocation oil field; South Wild Fork Creek gas condensate field; South Womack Hill oil field; Southeast Chatom gas condensate field; Southwest Barrytown oil field; and Souwilpa Creek gas condensate field.

  5. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation

    SciTech Connect

    Kopasaka-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D; Hall, D.R.

    1992-06-01

    This volume contains maps, well log correlated to lithology, porosity and permeability, structural cross section, graph of production history, porosity vs. natural log permeability plots; detailed core log, porosity vs. natural permeability plot for one lithofacies, paragenetic sequence and reservoir characterization sheet for the following fields in southwest Alabama: Stave Creek oil field; Sugar Ridge oil field; Toxey oil field, Turkey Creed oil field; Turnerville oil field, Uriah oil field; Vocation oil field; Wallace oil field; Wallers Creek oil field; West Appleton oil field; West Barrytown oil field; West Bend oil field; West Okatuppa Creed oil field; Wild Fork Creek oil field; Wimberly oil field; Womack Hill oil field; and Zion Chapel oil field. (AT)

  6. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. Appendix 1, Volume 4

    SciTech Connect

    Kopasaka-Merkel, D.C.; Moore, H.E. Jr.; Mann, S.D; Hall, D.R.

    1992-06-01

    This volume contains maps, well log correlated to lithology, porosity and permeability, structural cross section, graph of production history, porosity vs. natural log permeability plots; detailed core log, porosity vs. natural permeability plot for one lithofacies, paragenetic sequence and reservoir characterization sheet for the following fields in southwest Alabama: Stave Creek oil field; Sugar Ridge oil field; Toxey oil field, Turkey Creed oil field; Turnerville oil field, Uriah oil field; Vocation oil field; Wallace oil field; Wallers Creek oil field; West Appleton oil field; West Barrytown oil field; West Bend oil field; West Okatuppa Creed oil field; Wild Fork Creek oil field; Wimberly oil field; Womack Hill oil field; and Zion Chapel oil field. (AT)

  7. An accurate dynamical electron diffraction algorithm for reflection high-energy electron diffraction

    NASA Astrophysics Data System (ADS)

    Huang, J.; Cai, C. Y.; Lv, C. L.; Zhou, G. W.; Wang, Y. G.

    2015-12-01

    The conventional multislice method (CMS) method, one of the most popular dynamical electron diffraction calculation procedures in transmission electron microscopy, was introduced to calculate reflection high-energy electron diffraction (RHEED) as it is well adapted to deal with the deviations from the periodicity in the direction parallel to the surface. However, in the present work, we show that the CMS method is no longer sufficiently accurate for simulating RHEED with the accelerating voltage 3-100 kV because of the high-energy approximation. An accurate multislice (AMS) method can be an alternative for more accurate RHEED calculations with reasonable computing time. A detailed comparison of the numerical calculation of the AMS method and the CMS method is carried out with respect to different accelerating voltages, surface structure models, Debye-Waller factors and glancing angles.

  8. Neutron diffraction studies of liquid iso-propanol

    NASA Astrophysics Data System (ADS)

    Zetterström, P.; Dahlborg, U.; Delaplane, R. G.; Howells, W. S.

    1991-07-01

    The structure of deuterated liquid iso-propanol has been studied with neutron diffraction at the LAD diffractometer at the ISIS spallation source. Measurements were performed at temperatures 190, 220, 250 and 275 K. To correct for inelastic effects a model for the dynamic structure factor which obeys detailed balance and included recoil effects was used. The static molecular structure factor SM(Q) exhibits a pre-peak at about 0.75 Å-1. The origin of the pre-peak, which increases in amplitude with temperature, is presently unknown. The structure of the iso-propanol molecule was obtained from the total pair distribution function and from a fit of the intramolecular form factor f1(Q) to the measured SM(Q) at large Q. The obtained values of the bond length and Debye-Waller factors are in good agreement to those obtained from lower alcohols.

  9. Coherent X-ray Scattering from Liquid-Air Interfaces

    NASA Astrophysics Data System (ADS)

    Shpyrko, Oleg

    Advances in synchrotron x-ray scattering techniques allow studies of structure and dynamics of liquid surfaces with unprecedented resolution. I will review x-ray scattering measurements of thermally excited capillary fluctuations in liquids, thin polymer liquid films and polymer surfaces in confined geometry. X-ray Diffuse scattering profile due to Debye-Waller like roughening of the surface allows to probe the distribution of capillary fluctuations over a wide range of length scales, while using X-ray Photon Correlation Spectroscopy (XPCS) one is able to directly couple to nanoscale dynamics of these surface fluctuations, over a wide range of temporal and spacial scales. I will also discuss recent XPCS measurements of lateral diffusion dynamics in Langmuir monolayers assembled at the liquid-air interface. This research was supported by NSF CAREER Grant 0956131.

  10. Intermediate range order dynamics - key to understanding of the glass transition

    NASA Astrophysics Data System (ADS)

    Russina, Margarita; Mezei, Ferenc

    2000-03-01

    Introducing a new experimental approach allowed us to extend the study of the collective dynamics to the length scale of intermediate range order in the model glass former Ca-K-NO 3 (CKN) using time-of-flight (NEAT/BENSC) and spin-echo (InLL/ILL) technique. Our results provide for the first time direct experimental evidence that the β-process is of relaxational nature and corresponds to fast heterogeneous flow of groups of atoms.We did not observe any sign of the sharp singularity of the effective Debye-Waller factor, which could be an indication of the mode coupling theory critical temperature (Gotze, Z. Phys. 60 (1985) 195; Gotze and Sjogren, Rep. Progr. Phys. 55 (1992) 242).

  11. Gastro-intestinal nematode infection in lambs — A model based on climatic indices for forecasting peak pasture larval contamination

    NASA Astrophysics Data System (ADS)

    Paton, G.

    1987-06-01

    The parasite Ostertagia circumcincta is the primary cause of parasitic gastro-enteritis in lambs during their first season at grass. The life-cycle of this nematode parasite involves the development and survival of the free-living stages on pasture. Accordingly the pasture is the site of deposition, development and transmission of infection and meteorological factors affecting the pasture will affect the parasites. In this paper two empirical models for forecasting the timing of the “summer wave” of infective larvae on pasture are presented. These models are similar in form to that described by Starr and Thomas (1980) but involve different approaches to assessing the temperature and moisture components of the daily index value. Further, using the prediction model described by Paton, Thomas and Waller (1984) as an investigative tool, certain tentative suggestions are made as to a general fundamental weakness of empirical index methods.

  12. Automated, ab initio calculations of X-ray spectra including many-body excitations and vibrational damping

    NASA Astrophysics Data System (ADS)

    Jorissen, Kevin; Story, Shauna; Rehr, John

    2014-03-01

    Accurate calculations of x-ray absorption spectra (XAS) often require linking several materials science codes. To reduce the complexity and support the hardware requirements of such calculations, we have virtualized XAS modeling workflows using a Cloud-based approach, with interfacing and configuration of codes handled by developers, and virtual HPC resources allocated on demand. When coupled to user-friendly GUIs this puts powerful multi-code simulations in the hands of general users. For instance, FEFF users can improve XAS interpretation and analysis using accurate ab initio Debye-Waller factors and self energy from the ABINIT DFT code, rather than semi-empirical models. Additionally, such workflows allow robust automation of large-scale calculation sets such as the Materials Project where our approach could enable a theoretical spectroscopy database of many thousands of structures for systematic study of materials. Supported by NSF-1216716.

  13. Flat-ramp vs. convex-concave thrust geometries in a deformable hanging wall: new insights from analogue modeling experiments

    NASA Astrophysics Data System (ADS)

    Almeida, Pedro; Tomas, Ricardo; Rosas, Filipe; Duarte, Joao; Terrinha, Pedro

    2015-04-01

    Different modes of strain accommodation affecting a deformable hanging-wall in a flat-ramp-flat thrust system were previously addressed through several (sandbox) analog modeling studies, focusing on the influence of different variables, such as: a) thrust ramp dip angle and friction (Bonini et al, 2000); b) prescribed thickness of the hanging-wall (Koy and Maillot, 2007); and c) sin-thrust erosion (compensating for topographic thrust edification, e.g. Persson and Sokoutis, 2002). In the present work we reproduce the same experimental procedure to investigate the influence of two different parameters on hanging-wall deformation: 1) the geometry of the thrusting surface; and 2) the absence of a velocity discontinuity (VD) that is always present in previous similar analogue modeling studies. Considering the first variable we use two end member ramp geometries, flat-ramp-flat and convex-concave, to understand the control exerted by the abrupt ramp edges in the hanging-wall stress-strain distribution, comparing the obtain results with the situation in which such edge singularities are absent (convex-concave thrust ramp). Considering the second investigated parameter, our motivation was the recognition that the VD found in the different analogue modeling settings simply does not exist in nature, despite the fact that it has a major influence on strain accommodation in the deformable hanging-wall. We thus eliminate such apparatus artifact from our models and compare the obtained results with the previous ones. Our preliminary results suggest that both investigated variables play a non-negligible role on the structural style characterizing the hanging-wall deformation of convergent tectonic settings were such thrust-ramp systems were recognized. Acknowledgments This work was sponsored by the Fundação para a Ciência e a Tecnologia (FCT) through project MODELINK EXPL/GEO-GEO/0714/2013. Pedro Almeida wants to thank to FCT for the Ph.D. grant (SFRH/BD/52556/2014) under the

  14. Ultrafast interfacial electron transfer from the excited state of anchored molecules into a semiconductor

    NASA Astrophysics Data System (ADS)

    Gundlach, L.; Ernstorfer, R.; Willig, F.

    Ultrafast heterogeneous electron transfer (HET) from the excited singlet state of the large organic chromophore perylene into the inorganic semiconductor rutile TiO 2 was investigated with femtosecond time-resolved two-photon photoemission (TR-2PPE). The strength of the electronic interaction between the chromophore and the semiconductor was varied by inserting different anchor/bridge groups that functioned either as electronic wire or electronic tunnelling barrier. Both anchor groups, i.e. carboxylic and phosphonic acid, formed strong chemical bonds at the TiO 2 surface. The perylene chromophore with the different anchor/bridge groups was adsorbed from solution in a dedicated ultra-high-vacuum (UHV) chamber. The adsorption geometry of the chromophore perylene was determined from angle and polarization dependent two-photon photoemission (2PPE) signals and was found to be very different for the two different anchor/bridge groups. The measured adsorption geometries are compatible with recent DFT (density functional theory) calculations by P. Persson and co-workers [M. Nilsing, S. Lunell, P. Persson, L. Ojamäe, Phosphonic acid adsorption at the TiO 2 anatase (1 0 1) surface investigated by periodic hybrid HF-DFT computations, Surf. Sci. 582 (2005) 49-60]. Two different processes contributed to the TR-2PPE transients, firstly electron transfer from the chromophore to the electronic acceptor states on the surface and secondly escape of the electrons from the surface into the bulk of the semiconductor. The latter escape process was measured separately by making the interfacial electron injection process instantaneous when the chromophore catechol was employed in place of the perylene compounds. The thus measured electron escape behavior was governed by the same time constants that have recently been predicted by Prezhdo and coworkers from time dependent DFT calculations [W.R. Duncan, W.M. Stier, O.V. Prezhdo, Ab initio nonadiabatic molecular dynamics of the ultrafast

  15. Moessbauer spectroscopic investigations of bimetallic FeCo, FeNi, and FeRu model catalysts supported on magnesium hydroxide carbonate

    SciTech Connect

    Nagorny, K.; Bubert, S.

    1987-11-01

    FeCo, FeNi, and FeRu alloys supported on basic magnesium carbonate have been prepared by precipitation from salt solutions at 340 K onto the support using ion exchange and have been subsequently annealed for 20 h under argon. The reduction, oxidation, and sintering behavior of the samples under H/sub 2/ or CO exposure has been investigated at 723 K by means of Moessbauer spectroscopy. The comparison of the resonance absorption areas of the spectra taken at 4 and 295 K allowed the calculation of the Debye temperatures and Debye-Waller factors of the different components. From the Debye-Waller factors the relative fractions could be extrapolated to the conditions at 0 K. The kinetics of the H/sub 2/ exposure showed an increase in the reduction velocity as well as in the degree of reduction in the sequence FeCo < FeNi < FeRu. Above a critical particle diameter a phase separation occurred because of the segregation of an iron-rich phase at the surface of the alloy particles. The kinetics of the CO exposure demonstrated that with FeCo clusters iron(III) surface oxide layers form, whereas with FeNi clusters iron(II) surface oxide layers are generated. FeCo clusters with a cobalt content of 25% form only unstable surface carbides, whereas clusters with a cobalt content of about 5% form stable bulk carbides. The velocity of carbide formation increases with decreasing particle size. Based on the present data a model is proposed which explains the behavior of FeMe/magnesium hydroxide carbonates catalysts in H/sub 2/ and CO atmospheres.

  16. EXAFS and XANES investigation of (Li, Ni) codoped ZnO thin films grown by pulsed laser deposition.

    PubMed

    Mino, Lorenzo; Gianolio, Diego; Bardelli, Fabrizio; Prestipino, Carmelo; Senthil Kumar, E; Bellarmine, F; Ramanjaneyulu, M; Lamberti, Carlo; Ramachandra Rao, M S

    2013-09-25

    Ni doped, Li doped and (Li, Ni) codoped ZnO thin films were successfully grown using a pulsed laser deposition technique. Undoped and doped ZnO thin films were investigated using extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge spectroscopy (XANES). Preliminary investigations on the Zn K-edge of the undoped and doped ZnO thin films revealed that doping has not influenced the average Zn-Zn bond length and Debye-Waller factor. This shows that both Ni and Li doping do not appreciably affect the average local environment of Zn. All the doped ZnO thin films exhibited more than 50% of substitutional Ni, with a maximum of 77% for 2% Ni and 2% Li doped ZnO thin film. The contribution of Ni metal to the EXAFS signal clearly reveals the presence of Ni clusters. The Ni-Ni distance in the Ni(0) nanoclusters, which are formed in the film, is shorter with respect to the reference Ni metal foil and the Debye-Waller factor is higher. Both facts perfectly reflect what is expected for metal nanoparticles. At the highest doping concentration (5%), the presence of Li favors the growth of a secondary NiO phase. Indeed, 2% Ni and 5% Li doped ZnO thin film shows %Nisub = 75 ± 11, %Nimet = 10 ± 8, %NiO = 15 ± 8. XANES studies further confirm that the substitutional Ni is more than 50% in all the samples. These results explain the observed magnetic properties. PMID:23988792

  17. The effect of the exchange-correlation functional on H{sub 2} dissociation on Ru(0001)

    SciTech Connect

    Wijzenbroek, M.; Kroes, G. J.

    2014-02-28

    The specific reaction parameter (SRP) approach to density functional theory (DFT) has enabled a chemically accurate description of reactive scattering experiments for activated H{sub 2}–metal systems (H{sub 2} + Cu(111) and Cu(100)), but its application has not yet resulted in a similarly accurate description of non-activated or weakly activated H{sub 2}-metal systems. In this study, the effect of the choice of the exchange-correlation functional in DFT on the potential energy surface and dynamics of H{sub 2} dissociation on Ru(0001), a weakly activated system, is investigated. In total, full potential energy surfaces were calculated for over 20 different functionals. The functionals investigated include functionals incorporating an approximate description of the van der Waals dispersion in the correlation functional (vdW-DF and vdW-DF2 functionals), as well as the revTPSS meta-GGA. With two of the functionals investigated here, which include vdW-DF and vdW-DF2 correlation, it has been possible to accurately reproduce molecular beam experiments on sticking of H{sub 2} and D{sub 2}, as these functionals yield a reaction probability curve with an appropriate energy width. Diffraction probabilities computed with these two functionals are however too high compared to experimental diffraction probabilities, which are extrapolated from surface temperatures (T{sub s}) ⩾ 500 K to 0 K using a Debye–Waller model. Further research is needed to establish whether this constitutes a failure of the two candidate SRP functionals or a failure of the Debye–Waller model, the use of which can perhaps in future be avoided by performing calculations that include the effect of surface atom displacement or motion, and thereby of the experimental T{sub s}.

  18. [Prediction of short loops in the proteins with internal disorder].

    PubMed

    Deriusheva, E I; Galzitskaia, O V; Serdiuk, I N

    2008-01-01

    New possibility of the FoldUnfold program for prediction of short disordered regions (loops), which appears by using the short window width (3 amino acid residues), was described. For three representatives of the proteins G family the FoldUnfold program predicted almost all short loops and yield results are well compatible with the X-ray structure data. We have classified the loops predicted in the protein Ras-p21 structure in two types. In the first type, loops have high values of the Debye-Waller factor typical of the so-called functional loops (flexible loops). In the other type, loops have lower values of the Debye-Waller factor and can be considered as loops connecting secondary structure elements (rigid loops). When the results of prediction with the use of our program are compared with the results of other programs (PONDR, RONN, DisEMBL, PreLINK, IUPred, GlobPlot 2, FoldIndex), it is seen that the first enables far better prediction of short loop positions. Use of FoldUnfold for ubiquitin-like domain h-PLIC-2 allows to resolve such task as definition of boundary between the structured and unstructured regions in proteins with a big portion of disordered regions. The FoldUnfold program defines a clear boundary between the structured and unstructured regions at amino acid residues 30-31,whereas each of the other programs outlines the boundary from the 28-th amino acid residues through the 70th. PMID:19140328

  19. Probing interlayer interactions between graphene and metal substrates by supersonic rare-gas atom scattering

    NASA Astrophysics Data System (ADS)

    Shichibe, H.; Satake, Y.; Watanabe, K.; Kinjyo, A.; Kunihara, A.; Yamada, Y.; Sasaki, M.; Hayes, W. W.; Manson, J. R.

    2015-04-01

    We demonstrate that highly surface-sensitive supersonic rare-gas (He, Ar, and Xe) atom scattering, in both the quantum and classical regimes, can probe and quantify the interlayer interactions between graphene monolayers and metal substrates in terms of the Debye temperature corresponding to the surface normal vibration, and the surface effective mass. As models of the strongly and weakly interacting graphene, we investigated two systems, graphene on Ru(0001) and Pt(111), respectively. The experimental data for Ar and Xe are compared with the results from theoretical simulations based on the classical smooth surface model. For gr/Pt(111) we find that the scattering pattern of the rare-gas beam, including the Debye-Waller attenuation of the He beam, are quite similar to that from highly oriented pyrolytic graphite (HOPG); this suggests that the graphene-Pt(111) interaction is much like a van der Waals interaction. On the contrary, for the gr/Ru(0001) system, we find a smaller Debye-Waller attenuation and a larger surface effective mass, indicating that graphene on Ru(0001) is tightly bonded to the substrate. Furthermore, asymmetrical spectral shapes in the Ar and Xe scattering spectra from gr/Ru(0001) are interpreted as a result of the lateral distribution of the interlayer interaction corresponding to the moiré pattern. It is found that the "valley" region of the moiré pattern has high effective mass reflecting stronger bonding to the substrate, contributing to the high reflectivity of the He beam reported for this system. On the other hand, the effective mass of the "hill" region is found to be similar to that of HOPG, indicating that this region is well decoupled from the substrate. These results demonstrate a unique capability of atom scattering to probe and evaluate the molecule-substrate interaction and its spatial distributions.

  20. Surface-state Mediated Interactions: Analytic and Numerical Results for 3 Adatoms

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Einstein, T. L.

    2002-03-01

    When mediated by an isotropic Shockley surface-state band (e.g. on noble-metal (111) surfaces), indirect oscillatory electronic interactions between adsorbed atoms(TLE, in Handbook of Surf. Sci.) 1, ed. W. N. Unertl (Elsevier, 1996). are both strong and (in contrast to bulk-mediated interactions) slowly decaying with separation. Moreover, their simple analytical form(P. Hyldgaard and M. Persson, J. Phys.: Cond. Matt. 12), L13 (2000). has been observed experimentally.(J. Repp et al., PRL 85), 2981 (2000); K. Knorr et al., preprint. The s-wave phase shift needed for analysis is obtained from STM images of standing-wave patterns. The interaction of three adsorbed atoms is the sum of the 3 such pair energies plus a trio contribution from electrons traversing the perimeter, d, of the three-adatom cluster.^2,(T. L. Einstein, Surf. Sci. 84), L497 (1979). This trio contribution has a slightly weaker amplitude than the pair energy and a slightly faster asymptotic envelope decay, d-5/2. It also has a different but well-defined d-dependent oscillation period. The asymptotic description is compared with exact model calculations. It should be observable experimentally. http://www2.physics.umd.edu/ einstein/

  1. Determining the Locations of Brown Dwarfs in Young Star Clusters

    NASA Technical Reports Server (NTRS)

    Porter, Lauren A.

    2005-01-01

    Brown dwarfs are stellar objects with masses less than 0.08 times that of the Sun that are unable to sustain nuclear fusion. Because of the lack of fusion, they are relatively cold, allowing the formation of methane and water molecules in their atmospheres. Brown dwarfs can be detected by examining stars' absorption spectra in the near-infrared to see whether methane and water are present. The objective of this research is to determine the locations of brown dwarfs in Rho Ophiuchus, a star cluster that is only 1 million years old. The cluster was observed in four filters in the near-infrared range using the Wide-Field Infra-Red Camera (WIRC) on the 100" DuPont Telescope and Persson's Auxiliary Nasymith Infrared Camera (PANIC) on the 6.5-m Magellan Telescope. By comparing the magnitude of a star in each of the four filters, an absorption spectrum can be formed. This project uses standard astronomical techniques to reduce raw frames into final images and perform photometry on them to obtain publishable data. Once this is done, it will be possible to determine the locations and magnitudes of brown dwarfs within the cluster.

  2. The Mid-Infrared Cepheid Distance Scale: A Reconnaissance Program of Cepheids in the Local Group

    NASA Astrophysics Data System (ADS)

    Madore, Barry; Freedman, Wendy; Mager, Violet; Rigby, Jane

    2008-03-01

    We request archival funding to search for serendipitous IRAC detections of known Cepheids in Local Group galaxies. This archival proposal is a parallel study in support of a Cycle 5 GO proposal (PI: Freedman) to re-calibrate the Cepheid distance scale from the ground up using new IRAC photometry of ten Galactic Cepheids having HST trigonometric parallaxes (Benedict et al. 2007), in combination with eighty LMC Cepheids (from Persson et al. 2004), to establish the slope and secure the zero point of the Cepheid Period-Luminosity Relation at 3.6 and 4.5 micron. Here we intend to characterize the mid-infrared detectability of Cepheids in Local Group galaxies, by examining upwards of 8,000 archival images containing cataloged Cepheids with known periods and predicted luminosities. The Cepheids in these images exhibit a wide range of background intensity, often have complex crowding, and have a wide range of apparent magnitudes. From this reconnaissance survey we will be able to directly assess the ability of Spitzer to obtain high signal-to-noise observations of Cepheids in individual Local Group galaxies, and we will select the least crowded and least confused of the serendipitously--obserserved Cepheids. We plan to target this sample in the Warm Mission, with the goal of putting the Local Group securely onto the mid-infrared Cepheid distance scale.

  3. Elucidating the contact mechanics of aluminum silicon surfaces with Green's function molecular dynamics

    NASA Astrophysics Data System (ADS)

    Campañá, Carlos; Müser, Martin H.; Denniston, Colin; Qi, Yue; Perry, Thomas A.

    2007-12-01

    We study the contact mechanics of a flat, elastic wall pressed against a rigid substrate with Green's function molecular dynamics. The substrate's height profiles are parametrized from atomic force microscope topography measurements of two different aluminum-silicon alloys. In both samples, roughness lives on disparate length scales, i.e., on relatively large scales defined by size and mean separation of load-bearing silicon particles and on much smaller scales associated with the roughness on top of individual particles. The major differences between the two alloys are their silicon content and the typical silicon particle geometry. These differences lead to quite different stress distributions on both mesoscale and microscale in our calculations. A common feature is that the stress distribution decays exponentially for large stresses σ and not like a Gaussian. Persson's contact mechanics theory is generalized to the case where contact can only occur on silicon particles. This generalization predicts relatively accurate microscopic mean square stresses, however, it fails to predict accurate numbers for mean square stresses on the mesoscopic scales. Local overlap models are not accurate either, because they fail to describe the contact morphology.

  4. Tracking changes in natural organic carbon character during artificial infiltration using flourescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Köhler, Stephan J.; Lavonen, Elin; McCleaf, Philip; Hummel, Angelica; Berggren Kleja, Dan; Johansson, Per-Olof

    2016-04-01

    In many Nordic countries more than half of the drinking water is produced using surface water. Artificial infiltration allows increasing water withdrawal from groundwater but may not be sustainable during longer periods. Here we report results from a one year study on changes in dissolved organic carbon concentration (DOC) and DOC character along the whole infiltration area starting with the stream water until the drinking water plant raw water intake. Both DOC, fluorescence spectroscopy and LC-OCD are used to understand the observed changes in the aquatic phase. Large seasonal changes close to the infiltration basin contrasts with stable conditions further away. Selective removal of terrestrial type of DOC is coherent using both analytical techniques. A simple empirical relationship between Humic like material and absorbance developed elsewhere also holds in this system (Köhler et al 2016). Fluorescence is a fast and promising tool for tracking changes in natural organic carbon character during artificial infiltration. References Stephan J. Köhler, Elin Lavonen, Alexander Keucken, Philippe Schmitt-Kopplin, Tom Spanjer and Kenneth Persson. Upgrading coagulation with hollow-fibre nanofiltration for improved organic matter removal during surface water treatment Water research (2016) 89:232-240.

  5. HESS Opinions "On forecast (in)consistency in a hydro-meteorological chain: curse or blessing?"

    NASA Astrophysics Data System (ADS)

    Pappenberger, F.; Cloke, H. L.; Persson, A.; Demeritt, D.

    2011-01-01

    Flood forecasting increasingly relies on Numerical Weather Prediction (NWP) forecasts to achieve longer lead times (see Cloke et al., 2009; Cloke and Pappenberger, 2009). One of the key difficulties that is emerging in constructing a decision framework for these flood forecasts is when consecutive forecasts are different, leading to different conclusions regarding the issuing of forecasts, and hence inconsistent. In this opinion paper we explore some of the issues surrounding such forecast inconsistency (also known as "jumpiness", "turning points", "continuity" or number of "swings"; Zoster et al., 2009; Mills and Pepper, 1999; Lashley et al., 2008). We begin by defining what forecast inconsistency is; why forecasts might be inconsistent; how we should analyse it; what we should do about it; how we should communicate it and whether it is a totally undesirable property. The property of consistency is increasingly emerging as a hot topic in many forecasting environments (for a limited discussion on NWP inconsistency see Persson, 2011). However, in this opinion paper we restrict the discussion to a hydro-meteorological forecasting chain in which river discharge forecasts are produced using inputs from NWP. In this area of research (in)consistency is receiving recent interest and application (see e.g., Bartholmes et al., 2008; Pappenberger et al., 2011).

  6. Extremely red objects in the fields of high redshift radio galaxies

    NASA Technical Reports Server (NTRS)

    Persson, S. E.; Mccarthy, P. J.; Dressler, Alan; Matthews, Keith

    1993-01-01

    We are engaged in a program of infrared imaging photometry of high redshift radio galaxies. The observations are being done using NICMOS2 and NICMOS3 arrays on the DuPont 100-inch telescope at Las Campanas Observatory. In addition, Persson and Matthews are measuring the spectral energy distributions of normal cluster galaxies in the redshift range 0 to 1. These measurements are being done with a 58 x 62 InSb array on the Palomar 5-m telescope. During the course of these observations we have imaged roughly 20 square arcminutes of sky to limiting magnitudes greater than 20 in the J, H, and K passbands (3 sigma in 3 square arcseconds). We have detected several relatively bright, extremely red, extended objects during the course of this work. Because the radio galaxy program requires Thuan-Gunn gri photometry, we are able to construct rough photometric energy distributions for many of the objects. A sample of the galaxy magnitudes within 4 arcseconds diameter is given. All the detections are real; either the objects show up at several wavelengths, or in subsets of the data. The reddest object in the table, 9ab'B' was found in a field of galaxies in a rich cluster at z = 0.4; 9ab'A' lies 8 arcseconds from it.

  7. ADENOVIRUS INTERACTION WITH ITS CELLULAR RECEPTOR CAR.

    SciTech Connect

    HOWITT,J.; ANDERSON,C.W.; FREIMUTH,P.

    2001-08-01

    The mechanism of adenovirus attachment to the host cell plasma membrane has been revealed in detail by research over the past 10 years. It has long been known that receptor binding activity is associated with the viral fibers, trimeric spike proteins that protrude radially from the vertices of the icosahedral capsid (Philipson et al. 1968). In some adenovirus serotypes, fiber and other virus structural proteins are synthesized in excess and accumulate in the cell nucleus during late stages of infection. Fiber protein can be readily purified from lysates of cells infected with subgroup C viruses, for example Ad2 and Ad5 (Boulanger and Puvion 1973). Addition of purified fiber protein to virus suspensions during adsorption strongly inhibits infection, indicating that fiber and intact virus particles compete for binding sites on host cells (Philipson et al. 1968; Hautala et al. 1998). Cell binding studies using purified radiolabeled fiber demonstrated that fiber binds specifically and with high affinity to the cell plasma membrane, and that cell lines typically used for laboratory propagation of adenovirus have approximately 10{sup 4} high-affinity receptor sites per cell (Persson et al. 1985; Freimuth 1996). Similar numbers of high-affinity binding sites for radiolabeled intact virus particles also were observed (Seth et al. 1994).

  8. New insights on the Karoo shale gas potential from borehole KZF-1 (Western Cape, South Africa)

    NASA Astrophysics Data System (ADS)

    Campbell, Stuart A.; Götz, Annette E.; Montenari, Michael

    2016-04-01

    A study on world shale reserves conducted by the Energy Information Agency (EIA) in 2013 concluded that there could be as much as 390 Tcf recoverable reserves of shale gas in the southern and south-western parts of the Karoo Basin. This would make it the 8th-largest shale gas resource in the world. However, the true extent and commercial viability is still unknown, due to the lack of exploration drilling and modern 3D seismic. Within the framework of the Karoo Research Initiative (KARIN), two deep boreholes were drilled in the Eastern and Western Cape provinces of South Africa. Here we report on new core material from borehole KZF-1 (Western Cape) which intersected the Permian black shales of the Ecca Group, the Whitehill Formation being the main target formation for future shale gas production. To determine the original source potential for shale gas we investigated the sedimentary environments in which the potential source rocks formed, addressing the research question of how much sedimentary organic matter the shales contained when they originally formed. Palynofacies indicates marginal marine conditions of a stratified basin setting with low marine phytoplankton percentages (acritarchs, prasinophytes), good AOM preservation, high terrestrial input, and a high spores:bisaccates ratio (kerogen type III). Stratigraphically, a deepening-upward trend is observed. Laterally, the basin configuration seems to be much more complex than previously assumed. Furthermore, palynological data confirms the correlation of marine black shales of the Prince Albert and Whitehill formations in the southern and south-western parts of the Karoo Basin with the terrestrial coals of the Vryheid Formation in the north-eastern part of the basin. TOC values (1-6%) classify the Karoo black shales as promising shale gas resources, especially with regard to the high thermal maturity (Ro >3). The recently drilled deep boreholes in the southern and south-western Karoo Basin, the first since the

  9. Seine estuary modelling and AirSWOT measurements validation

    NASA Astrophysics Data System (ADS)

    Chevalier, Laetitia; Lyard, Florent; Laignel, Benoit

    2013-04-01

    In the context of global climate change, knowing water fluxes and storage, from the global scale to the local scale, is a crucial issue. The future satellite SWOT (Surface Water and Ocean Topography) mission, dedicated to the surface water observation, is proposed to meet this challenge. SWOT main payload will be a Ka-band Radar Interferometer (KaRIn). To validate this new kind of measurements, preparatory airborne campaigns (called AirSWOT) are currently being designed. AirSWOT will carry an interferometer similar to Karin: Kaspar-Ka-band SWOT Phenomenology Airborne Radar. Some campaigns are planned in France in 2014. During these campaigns, the plane will fly over the Seine River basin, especially to observe its estuary, the upstream river main channel (to quantify river-aquifer exchange) and some wetlands. The present work objective is to validate the ability of AirSWOT and SWOT, using a Seine estuary hydrodynamic modelling. In this context, field measurements will be collected by different teams such as GIP (Public Interest Group) Seine Aval, the GPMR (Rouen Seaport), SHOM (Hydrographic and Oceanographic Service of the Navy), the IFREMER (French Research Institute for Sea Exploitation), Mercator-Ocean, LEGOS (Laboratory of Space Study in Geophysics and Oceanography), ADES (Data Access Groundwater) ... . These datasets will be used first to validate locally AirSWOT measurements, and then to improve a hydrodynamic simulations (using tidal boundary conditions, river and groundwater inflows ...) for AirSWOT data 2D validation. This modelling will also be used to estimate the benefit of the future SWOT mission for mid-latitude river hydrology. To do this modelling,the TUGOm barotropic model (Toulouse Unstructured Grid Ocean model 2D) is used. Preliminary simulations have been performed by first modelling and then combining to different regions: first the Seine River and its estuarine area and secondly the English Channel. These two simulations h are currently being

  10. Spectro-dynamical asteroid families in the main belt

    NASA Astrophysics Data System (ADS)

    Bus, S.

    2014-07-01

    Spectral observations of collisionally-derived asteroid families continue to provide strong evidence that the surfaces of members from each family are spectrally homogeneous. This apparent homogeneity provides motivation to use new approaches in combining physical observations, such as spectral colors or albedo, with orbital parameters for the identification of family members and interlopers (e.g. [1,2]). The work described here uses the combined Sloan Digital Sky Survey colors (fourth release of the SDSS Moving Object Catalog [3]) and proper orbital elements from the Asteroids-Dynamics Site (AstDyS [4]) for 39,147 asteroids with semimajor axes between 2.1 and 3.2 au to search for ''spectro-dynamical'' families. The analysis is designed to identify groupings of asteroids that form statistically significant peaks in number density compared to the background population for a fixed spectral color distribution. A number of techniques from multivariate analysis are folded together and have been calibrated to accommodate asteroid families of different size, shape, and number density. In the final phase of the analysis, the number density for asteroids within a given spectral range is represented by 2-dimensional contour slices through proper-element space, and a visual inspection is made to confirm the reality of each grouping. Some families show evidence of complex structure that may be indicative of multiple collisional events over the history of the family. An example of this is the Karin family, which is located within the older, much larger Koronis family [5]. While both families are composed of asteroids classified as S-types, there is a significant color difference between the Koronis and Karin asteroids that is used to distinguish between members of the two families. In the same way, the Vesta family appears to be comprised of two distributions of asteroids that are offset in proper-element space and exhibit a statistically significant difference in the shape of