23,840 research outputs found
Turbulent sixties
No full textA collection of speeches, each with an introductory and concluding segment. Includes: a speech in Harlem on Mar. 29, 1964 by Malcolm X, an attack on Barry Goldwater's platform, delivered on July 14, 1964 by Nelson Rockefeller, Barry Goldwater's rebuttal of Rockefeller's speech, Ronald Reagan's speech in support of Goldwater, and the eulogy for Martin Luther King, Jr. by Robert F. Kennedy.Host, Jody Powell
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
The Powell-Cotton Dioramas and the Re-interpretation of an Idyll
No full textThis research examines the natural habitat dioramas created by Major P.H.G. Powell-Cotton, in doing so
it affects a remembering of a sense of place where a diorama reflects in Mieke Bal's view a three-dimensionality
that draws on architectural space; it then considers the three dimensional representation of
the landscape within the diorama itself; the two-dimensional illusion of a trompe l'oeil landscape
painting; and the exterior space occupied by the viewer. The Powell-Cotton natural habitat dioramas exist
behind large glass screens their purpose follows an aesthetic relationship with the emergence of the
natural habitat diorama and the ability to transfix perception through the re-interpretation of an idyll. The
potential for this practice-based research was to explore the possibility of developing an aesthetic for
sculpture and architectural space. However in focussing on the Powell-Cotton dioramas the notion of
aesthetic attitude would lose ground due to their idiosyncratic, artificial, and extraordinary nature, it then
prepared the basis of interpretation in establishing 'theatres of landscape' as an open concept. With
landscape, a sense of place anticipates various positions and numerous delays; it recollects the cognitive
knowledge brought to the prospect that involves aspects in, of and about landscape. Regarding the
studio-based project, the diorama was placed between the real and the unreal, challenging Bal's rationale
of the cognitive relationship of a diorama to the concept of a discursive space. Where both artist and
viewer 'activates' this space with their presence, they bring their own recollection of landscape and by
assigning landscape with memory the potentiality is where cognition becomes accentuated. Whereas the
unknown and uncharted can refute reality, memory is dependent on what is known both formally and
informally, it places the natural habitat diorama in a visual system that is both constructive and
destructive. Therefore the research methodology examines the historical context of the diorama through a
doctoral thesis by Karen Wonders and an analysis of Louis Daguerre's diorama by Richard Altick.
Following Bal's analysis of the diorama, this created a dilemma - in what ways are the perceptions of the
observer determined, and how are they undermined? Jonathan Crary and Giuliana Bruno considered the
diorama's position in relation to film and film archaeology, which ultimately the diorama and natural
habitat diorama could not compete with. In asking what has Powell-Cotton's museum to offer in the 21st
century, this thesis examines the concept of a diorama, its objectives and correspondingly its failings. As
the dioramas in the Powell-Cotton Museum were undocumented, these dioramas and their written, visual
and architectural relationship to Louis Daguerre offer a contribution to knowledge concurrent with the
relationship of this practice based research project. Whereupon the research diary forms the basis of a
contribution to new knowledge in the construction of small and large-scale dioramas, sculpture and
installations. By challenging Bal's analysis this research practice would investigate natural and projected
light and the visual language of transparency, translucency and opacity in the representation of landscape
and landscape as motif, and progressing to the structural implications of 2D and 3D work
MICROWAVE SPECTRUM OF THIOFORMALDEHYDE
No full textFiercis X. Powell is also on the laculty of The Catholic University of America, Washington, D.C.""Author Institution: National Bureau of StandardsThe microwave spectrum of the reactive species thioformaldehyde () has been investigated in the frequency range 3--70 GHz. A centrifugal distortion analysis has been completed for the species in the ground vibrational state and rotational constants have been obtained for the isotopic species , , and . A variety of production systems will be discussed along with structual conclusions and possible astronomical implications
Relations between x-ray timing features and spectral parameters of galactic black hole x-ray binaries
No full textWe present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX
339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer
(RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that
show a certain type of quasi-periodic oscillations (type-C QPOs). The spectral parameters are derived using the empirical convolution model simpl to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off, and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive
correlation between photon index and centroid frequency of the QPOs and reveal an anti-correlation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the “sombrero”
geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follow a general track, independent of individual outbursts
Scattered data fitting on surfaces using projected Powell-Sabin splines
No full textWe present C1 methods for either interpolating data or for fitting scattered data associated with a smooth function on a two-dimensional smooth manifold Ω embedded into R3. The methods are based on a local bivariate Powell-Sabin interpolation scheme, and make use of local projections on the tangent planes. The data fitting method is a two-stage method. We illustrate the performance of the algorithms with some numerical examples, which, in particular, confirm the O(h3) order of convergence as the data becomes dens
Combined use of the GGSFT data base and on Board Marine Collected Data to Model the Moho Beneath the Powell Basin, Antarctica
No full textThe Powell Basin is a small oceanic basin located at the NE end of the Antarctic Peninsula developed during the Early Miocene and mostly surrounded by the continental crusts of the South Orkney Microcontinent, South Scotia Ridge and Antarctic Peninsula margins. Gravity data from the SCAN 97 cruise obtained with the R/V Hespérides and data from the Global Gravity Grid and Sea Floor Topography (GGSFT) database (Sandwell and Smith, 1997) are used to determine the 3D geometry of the crustal-mantle interface (CMI) by numerical inversion methods. Water layer contribution and sedimentary effects were eliminated from the Free Air anomaly to obtain the total anomaly. Sedimentary effects were obtained from the analysis of existing and new SCAN 97 multichannel seismic profiles (MCS). The regional anomaly was obtained after spectral and filtering processes. The smooth 3D geometry of the crustal mantle interface obtained after inversion of the regional anomaly shows an increase in the thickness of the crust towards the continental margins and a NW-SE oriented axis of symmetry coinciding with the position of an older oceanic spreading axis. This interface shows a moderate uplift towards the western part and depicts two main uplifts to the northern and eastern sectors
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Sparganothoides ocrisana Kruse and Powell 2009, new species
No full text15. Sparganothoides ocrisana Kruse and Powell, new species Figs. 1, 21, 47, 75, 76, 103, 107 Diagnosis. Sparganothoides ocrisana is similar to S. capitiornata and S. canorisana, but the male genitalia are distinct, in particular the shapes of the valvae. Sparganothoides ocrisana exhibits the greatest sexual dimorphism of any species in the genus, with males considerably more strongly patterned than females. Description. Male. Head: Frons yellowish brown, smooth scaled; vertex roughened laterally, yellowish brown to brown, with a pair of exoskeletal protuberances between mesal-posterior margins of eyes, angled toward middle; one small elongate protuberance between antennae; broad area of densely packed, short, yellowish brown scales between front and rear protuberances; short, erect, yellowish white scales between posterior two protuberances. Labial palpus brownish yellow mesally, yellowish brown to brown laterally. Antennal scaling yellowish brown to brown. Thorax: Smooth scaled laterally, yellowish brown or brown with scattered dark brown scales, dense column of short yellowish white to brown scales mesally; tegula with clump of small orange or brown pointed scales at apex so that tegula appears truncated. Forewing length 7.8–9.1 mm (= 8.1; n = 10). Forewing costal fold shorter than 0.5 wing length, with costa often curled beyond middle; forewing ground color brownish yellow, with dense scattering of brown to grayish brown scales and spots; subbasal, median, and subterminal fascia brown with orange and dark brown scales extending from costa to dorsal margin either distinct and dark, thin and light brown, or absent; brown tornal mark part of median fascia when present; indistinct brown and orange transverse strigulae throughout subterminal and terminal areas; often with brown spot at apex of discal cell. Fringe brownish yellow. Hindwing yellowish white at base, gray at midwing, often with obscure dense gray transverse striae throughout. Abdomen: Genitalia (Fig. 21; slide #JAP6568; EME; Costa Rica, Puntarenas, Monteverde; n = 17) with uncus long, slender, curved, widened apically, with long setae dorsally and patch of small setae ventrally; tegumen slightly raised and subtriangular at base of uncus; socius subtriangular posteriorly, secondary arms long, slender, abruptly angled near middle, enlarged apices strongly asymmetrically bilobed, boot-shaped; transtilla well sclerotized, bilobed, spines small, numerous over posterior margin, anterior process reinforced with invagination at middle; valva subrectangular with sclerotized curved crease connecting to near base of sacculus and extending over two-thirds of valva; costa weakly concave; sacculus convex; pulvinus present; phallus pistol-shaped, aedeagus more strongly curved ventrally than dorsally, shorter than phallobase, with ventral lip apically, attached to juxta by a thin process; phallobase long, with a short bulb; cornuti with minute spine near base. Female. Head: Frons yellowish brown, smooth scaled; vertex roughened laterally, yellowish brown to brown. Labial palpus brownish yellow mesally, yellowish brown to brown laterally. Antennal scaling yellowish brown to brown. Thorax: Dorsum smooth scaled, yellowish brown or brown with scattered dark brown scales. Forewing length 8.7–10.4 mm (= 9.1; n = 10). Forewing ground color brownish yellow, heavily suffused with grayish brown; subbasal, median, and subterminal fascia suffused, grayish brown with orange and dark brown scales extending from costa to dorsal margin either distinct and dark or narrow and light grayish brown; grayish brown tornal mark part of median fascia; indistinct grayish brown or dark brown and orange transverse strigulae throughout subterminal and terminal areas; occasionally with brown spot at apex of discal cell. Fringe brownish yellow. Hindwing gray with obscure dense gray transverse striae throughout. Abdomen: Genitalia (Fig. 47; slide #5601; EME; Costa Rica, Puntarenas, Monteverde; n = 9) with papillae anales parallel-sided, subtriangular posteriorly; sterigma strongly sclerotized ventrally, concave anteriorly; ductus bursae short, widened anteriorly; corpus bursae large, irregularly rounded; signum more than three times longer than wide, bilobed, curved, attenuate at apices. Type material. Holotype: Male: COSTA RICA: PUNTARENAS: Monteverde, 1350–1400 m, 22–24.vii.1990, at lights, S. Meredith & J. Powell (EME). Paratypes (38♂, 47♀). COSTA RICA: GUANACASTE: Estación Cacao, 1100 m, 8–18.ii.1995 (1♂), M. Moraga (INBio). SW side Volcan Cacao, 1000–1400 m, v.1988 (1♂), C. Chaves (INBio). Lado suroeste del Volcan Cacao, 23.x–9.xi.1990 (1♀), C. Chaves (INBio). Estación Las Pailas, P. N. Rincon de la Vieja, 800 m, 22.vii.1992 (1$M), D. Garcia (INBio). Estación Maritza, Lado oeste del Volcán Orosi, 600 m, viii.1990 (1♂), C. Chaves (INBio). HEREDIA: Santa Domingo, 21–25.v.1996 (1♂), J. Powell (EME). PUNTARENAS: Estación Biol. Las Alturas, 12 km NE San Vito, 1550 m, 22–24.i.1993 (2♂), J. Powell (EME). Monteverde, 1400 m, 25–26.vi.1979 (2♂, 1♀), D. Janzen (INBio), 10–11.xii.1979 (1♀), D. Janzen (INBio), 1300 m, 17–20.v.1985 (1♂), P. Opler & J. Powell (EME), 8–10.vi.1986 (2♂, 1♀), J. Chemsak & H. Katsura (EME), 11.vi.1988 (2♂, 4♀), 12.vi.1988 (2♂, 12♀), 13.vi.1988 (1♂, 3♀), J. Brown & J. Powell (EME), 1350–1400 m, 22–24.vii.1990 (2♀), J. Powell (EME), reared from eggs on synthetic diet, emgd. 11.x–21.xi.1990 (6 M, 7 F), JAP 90G14, 22–24.vii.1990 (6♂, 9♀), S. Meredith & J. Powell (EME, NMNH), 29–31.iii.1992 (2♂, 1♀), J. McCarty & J. Powell (EME), reared from eggs on synthetic diet, emgd. 22.vi, vii.1992 (2♂, 1♀), JAP 92C64 (EME). Monteverde, Cloud Forest Reserve HQ, 1450 m, 18.v.1985 (1♂, 1♀), J. Chemsak, P. Opler & J. Powell (EME). Monteverde Lodge, 28.v.1994 (1♀), J. Brown (EME). GUATEMALA: Baleu, Mpio. San Cristóbal, Verapaz, Alta Verapaz, 1350 m, 8–15.viii.1985 (3♂, 2♀), E. Welling (EME). MEXICO: VERACRUZ: Río Metlec Canyon, NW Fortín de las Flores, 6.vii.1974 (1♂), J. Chemsak & J. Powell (EME). Immature stages. Eggs are orange to deep ochreous orange and laid in small, regularly overlapping patches of 7– 28 eggs per patch (= 18.2, n = 5). Embryos become translucent during development, hatching in 10–14 days. Early instars profusely webbed the edges of synthetic diet. Larvae were reared on synthetic diet, but some were able to feed on Prunus. The anal comb has eight tines. Development time ranged from six to nine weeks. Adults emerged within two weeks following pupation. Biology. Adults have been captured during every month of the year except April and September; the species is probably multivoltine in Costa Rica and perhaps bivoltine farther north. Distribution. Sparganothoides ocrisana has been recorded from Costa Rica, Guatemala, and Veracruz, Mexico, in disturbed or remnant rainforest habitat. Remarks. This species is variable and sexually dimorphic.The single specimen from Mexico is smaller than its conspecifics (forewing length = 7.8 mm). Etymology. The name is derived from the Greek “okris” (= projecting) and refers to the protuberances of the head.Published as part of Kruse, James J. & Powell, Jerry A., 2009, Systematics of Sparganothoides Lambert and Powell, 1986 (Lepidoptera: Tortricidae: Sparganothini), pp. 1-78 in Zootaxa 2150 (1) on pages 36-37, DOI: 10.11646/zootaxa.2150.1.1, http://zenodo.org/record/531143
Increased anxiety-like behavior in mice lacking the inhibitory synapse cell adhesion molecule neuroligin 2
No full textNeuroligins (NL) are postsynaptic cell adhesion molecules that are thought to specify synapse properties. Previous studies showed that mutant mice carrying an autism-associated point mutation in NL3 exhibit social interaction deficits, enhanced inhibitory synaptic function and increased staining of inhibitory synaptic puncta without changes in overall inhibitory synapse numbers. In contrast, mutant mice lacking NL2 displayed decreased inhibitory synaptic function. These studies raised two relevant questions. First, does NL2 deletion impair inhibitory synaptic function by altering the number of inhibitory synapses, or by changing their efficacy? Second, does this effect of NL2 deletion on inhibition produce behavioral changes? We now show that although NL2-deficient mice exhibit an apparent decrease in number of inhibitory synaptic puncta, the number of symmetric synapses as determined by electron microscopy is unaltered, suggesting that NL2 deletion impairs the function of inhibitory synapses without decreasing their numbers. This decrease in inhibitory synaptic function in NL2-deficient mice correlates with a discrete behavioral phenotype that includes a marked increase in anxiety-like behavior, a decrease in pain sensitivity and a slight decrease in motor co-ordination. This work confirms that NL2 modulates inhibitory synaptic function and is the first demonstration that global deletion of NL2 can lead to a selective behavioral phenotype
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