617 research outputs found
Detection of a Hot Binary Companion of Carinae
We report the detection of a hot companion of Carinae using high
resolution spectra (905 - 1180 \AA) obtained with the Far Ultraviolet
Spectroscopic Explorer (\fuse) satellite. Observations were obtained at two
epochs of the 2024-day orbit: 2003 June during ingress to the 2003.5 X-ray
eclipse and 2004 April several months after egress. These data show that
essentially all the far-UV flux from \etacar shortward of \lya disappeared at
least two days before the start of the X-ray eclipse (2003 June 29), implying
that the hot companion, \etaB, was also eclipsed by the dense wind or extended
atmosphere of \etaA. Analysis of the far-UV spectrum shows that \etaB is a
luminous hot star. The \nii \wll1084-1086 emission feature suggests that it may
be nitrogen-rich. The observed far-UV flux levels and spectral features,
combined with the timing of their disappearance, is consistent with \etacar\
being a massive binary system
Limits on O VI Emission from the Shocked Circumstellar Gas of SN 1987A
The Far Ultraviolet Spectroscopic Explorer (FUSE) was used to search for emission from the shock interaction of the ejecta of SN 1987A with its circumstellar material. FUSE observations of SN 1987A between 2000 and 2007 did not detect broad OVI emission. However, OVI emission was detected in 2000-2001 with a narrow line width (FWHM <35 kms t ) and a heliocentric radial velocity of +280 km/s. This places the emitting gas at rest relative to the supernova and is interpreted as emission from unshocked circumstellar gas. This narrow emission had disappeared in 2007 (and possibly earlier) as a result of the advancing shock overtaking the H II region that was flash ionized by the supernova explosion in 1987
Universitarios y prejuicio ?tnico: un estudio del prejuicio hacia el negro en los universitarios de Lima
Busca contribuir en la profundizaci?n de una nueva perspectiva sobre el prejuicio ?tnico, considerando que algunas corrientes de la sicolog?a social proponen la educaci?n como elemento b?sico para la reducci?n del prejuicio ?tnico, ignorando el contexto social global en el que se desenvuelven los individuos y eludiendo la instancia econ?mica como factor explicativo. Postula que siendo la universidad reflejo de la sociedad en la cual se inserta, va a reproducir los valores, normas y actitudes de la ideolog?a dominante en la que est? involucrado el prejuicio. Por tanto, este trabajo est? orientado a confirmar la existencia del prejuicio ?tnico en el ambiente acad?mico peruano, particularmente en el de las universidades de Lima. El cuestionario que se utiliz? para medir el grado de prejuicio hacia los negros fue aplicado, por muestreo, a 1,200 alumnos de las universidades San Marcos, La Cat?lica, San Mart?n y encontr? que el grado de prejuicio ?tnico en los estudiantes universitarios est? relacionado con determinadas caracter?sticas sociales, como edad, sexo, lugar de residencia. As?, quienes tienen proporcionalmente mayor grado de prejuicio ?tnico son los estudiantes hombres de m?s edad y que viven en las zonas m?s populares; puesto que son los que desarrollan mayores frustraciones e inseguridades por tener mayores responsabilidades y expectativas ?que los m?s j?venes, las mujeres y quienes viven en zonas intermedias o residenciales? que no pueden ser satisfechas por las condiciones materiales en que viven
Production and detection of doubly charmed tetraquarks
The feasibility of tetraquark detection is studied. For the cc\bar{u}\bar{d}
tetraquark we show that in present (SELEX, Tevatron, RHIC) and future
facilities (LHCb, ALICE) the production rate is promising and we propose some
detectable decay channels.Comment: 6 pages, 5 figure
Scanning electron microscopy of the tegumental surface of Heterobilharzia americana (Trematoda; Schistosomatidae)
An attempt is made in this paper to define more clearly the tegumental microstructure of the schistosome, Heterobilharzia americana. The adult parasites were examined with scanning electron microscopy at 75-10 000 magnifications. The morphology of the oral and ventral suckers, the tegument, and the gynecophoral canal with the in copula female were closely scrutinized. The tegument of the female is simple and uniform in structure, an adaptation which may allow for a more efficient mode of penetration through the smaller mesenteric venules. The male tegument, however, is characterized by papilla-like elevations of irregular size, shape, and distribution.
These papillae may represent different kinds of sensory endings.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
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Brexit-like rhetoric on immigration no longer works
BlogThe Government’s rhetoric on curbing immigration, and “stopping the small boats” in particular, has strong echoes of the Brexit campaign. As Matilde Rosina and Cristina Juverdeanu point out, the same themes, keywords, and even graphics are being used by the Government that were originally used by Brexit campaigners. The only difference is, this time the campaign doesn’t seem to be working
Studies on the parasites of zebra. II. Cylicostephanus longiconus n. sp. (Nematoda: Strongylidae) from the mountain zebra, Equus zebra hartmannae (Matschie , 1898)
A new species of nematode, Cylicostephanus longiconus, was collected from mountain zebra, Equus zebra hartmannae (Matschie, 1898), on the Kelpie farm in the Khomas Hochland, South West Africa/Namibia. These nematodes have 1 large dorsal and 2 small subventral teeth in the oesophageal funnel and submedian papillae with very long tips. The males have a very well-developed dermal collar and genital cone.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
Stiff‐Stilbene Ligands Target G‐Quadruplex DNA and Exhibit Selective Anticancer and Antiparasitic Activity
G-quadruplex nucleic acid structures have long been studied as anticancer targets whilst their potential in antiparasitic therapy has only recently been recognized and barely explored. Herein, we report the synthesis, biophysical characterization, and in vitro screening of a series of stiff-stilbene G4 binding ligands featuring different electronics, side-chain chemistries, and molecular geometries. The ligands display selectivity for G4 DNA over duplex DNA and exhibit nanomolar toxicity against Trypasanoma brucei and HeLa cancer cells whilst remaining up to two orders of magnitude less toxic to non-tumoral mammalian cell line MRC-5. Our study demonstrates that stiff-stilbenes show exciting potential as the basis of selective anticancer and antiparasitic therapies. To achieve the most efficient G4 recognition the scaffold must possess the optimal electronics, substitution pattern and correct molecular configuration.M.P.O. thanks the Bristol Chemical Synthesis Centre for Doctoral Training, funded by EPSRC (EP/L015366/1) and the University
of Bristol for a PhD studentship. J.C.M./P.P. thank Spanish Ministerio de Ciencia Innovación y Universidades (Grants CTQ2015-
64275-P and RTI2018-099036-B-I00). M.C.G. thanks the European Research Council (ERC-COG: 648239
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