Speckle Interferometry of Metal-Poor Stars in the Solar Neighborhood. I

We report the results of speckle-interferometric observations of 109 high proper-motion metal-poor stars made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We resolve eight objects -- G102-20, G191-55, BD+19$^\circ$~1185A, G89-14, G87-45, G87-47, G111-38, and G114-25 -- into individual components and we are the first to astrometrically resolve seven of these stars. New resolved systems included two triple (G111-38, G87-47) and one quadruple (G89-14) star. The ratio of single-to-binary-to-triple-to-quadruple systems among the stars of our sample is equal to 71:28:6:1.Comment: 8 pages, 4 figures, accepted to Astrophysical Bulleti

Intestinal and Blood Parasites of Man in Timor

Survey tinja dan darah dipulau Timor guna menentukan distribusi dan prevalensi penyakit parasit diantara penduduk telah dilakukan pada bulan Juli dan Agustus tahun 1972 sebagai kelanjutan dari deretan survey yang dilakukan oleh Direktorat Jenderal Pencegahan Pemberantasan Penyakit menular Departemen Kesehatan, Bagian Parasitologi dan Pathologi Umum Fakultas Kedokteran Universitas Indonesia dan US Namru-2 di Indonesia. Sejumlah 445 sediaan tinja untuk pemeriksaan parasit usus, 581 sediaan darah untuk pemeriksaan parasit malaria dan 663 sediaan darah untuk pemeriksaan parasit filaria telah diambil dari penduduk cara merata di 7 desa pada 3 kabupaten di Timor, Nusa Tenggara Timur. Enam puluh delapan per cent diantara penduduk melihatkan satu atau lebih parasit usus didalam tinjanya dimana cacing tambang merupakan parasit usus yang terbanyak. Ascaris lumbricoides ketemukan jauh lebih kurang daripada di Jawa, Sumatra dan Sulawesi, juga diketemukan perbedaan itara "intestinal parasite rate" di Timor Indonesia dan Timor Portugis. Dua belas percent penduduk yang diperiksa melihatkan parasit malaria didalam darahnya sedangkan parasit filaria ditemukan sebanyak 8 percent. Plasmodium falciparum merupakan parasit malaria yang terbanyak ditemukan, ia jenis parasit fdaria yang ditemukan adalah "Timor microfilaria" dan Wuchereria bancrofti dimana yang pertama merupakan parasit yang terbanyak diantara penduduk yang diperiksa

Critical Velocity in 3He-B Vibrating Wire Experiments as Analog of Vacuum Instability in a Slowly Oscillating Electric Field

The Lancaster experiments with a cylindrical wire moving in superfluid 3He-B are discussed, where the measured critical velocity of pair creation is much below the Landau critical velocity. The phenomenon is shown to be analogous to the instability of the electron-positron vacuum in an adiabatically alternating strong electric potential of both signs, where the positive- and negative-root levels cross and thus the instability treshold is twice less than in the conventional case of a single static potential well.Comment: RevTex file, 6 pages, 4 figure

Contact Patterns Among Bighorn Sheep In and Around Glacier National Park

Identifying patterns of direct contacts among individual animals is important to understanding infectious disease transmission. Social behavior can be influenced by both intrinsic and extrinsic variables and can be explored at 3 levels: social network structure, dyad structure, and contact structure. We investigated drivers of contact structure using GPS locations of 87 male and female bighorn sheep (Ovis canadensis) in and around Glacier National Park in Montana, USA. Focusing on contacts between sheep moving separately, we examined relationships between contact locations and movement variables, land cover, distances to various resources, and variables known to influence survival using a resource selection function. Used and available points were defined as simultaneous locations within 25 m (the contact-used) and 13 km (largest step length- available) of another collared bighorn sheep, thus results of this analysis describe the strengths of these variables relative to habitat use. Data were analyzed separately according to dyad type (male-male, female-female, malefemale). Most contacts occurred in March for male-male and female-female dyads and in November, December, and January for male-female dyads. For male-male dyads, contacts occurred more than expected given habitat use in conifer land cover and locations farther from perennial water sources, high NDVI, little canopy cover, and low and high solar radiation index. For female-female dyads, contacts occurred less than expected given habitat use in grass and barren land cover and locations with intermediate terrain ruggedness, high NDVI, and low and high snow water equivalent. For male-female dyads, contacts occurred most during the night, least during the day, and at locations with intermediate elevation and farther from escape terrain. Together, these results suggest that more specific conditions apply to contact locations than general locations and that we can predict locations where contacts are most likely to occur, which may be useful for disease management

Computational lens for the near field

A method is presented to reconstruct the structure of a scattering object from data acquired with a photon scanning tunneling microscope. The data may be understood to form a Gabor type near-field hologram and are obtained at a distance from the sample where the field is defocused and normally uninterpretable. Object structure is obtained by the solution of the inverse scattering problem within the accuracy of a perturbative, two-dimensional model of the object

The persuasive “power” of stigma

a b s t r a c t We predicted that able-bodied individuals and White Americans would have a difficult time saying no to persuasive appeals offered by disabled individuals and Black Americans, due to their desire to make such interactions proceed smoothly. In two experiments, we show that members of stigmatized groups have a peculiar kind of persuasive ''power'' in face-to-face interactions with non-stigmatized individuals. In Experiment 1, wheelchair-bound confederates were more effective in publicly soliciting donations to a range of charities than confederates seated in a regular chair. In Experiment 2, Whites changed their private attitudes more following face-to-face appeals from Black than White confederates, an effect mediated by their increased efforts to appear agreeable by nodding and expressing agreement. This difference was eliminated when impression management concerns were minimized -when participants viewed the appeals on video

Speckle Interferometry of Metal-Poor Stars in the Solar Neighborhood.II

The results of speckle interferometric observations of 115 metal-poor stars [m/H]<-1 within 250 pc from the Sun and with proper motions mu <= 0.2"/yr, made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, are reported. Close companions with separations ranging from 0.034" to 1" were observed for 12 objects - G76-21, G59-1, G63-46, G135-16, G168-42, G141-47, G142-44, G190-10, G28-43, G217-8, G130-7, and G89-14 - eight of them are astrometrically resolved for the first time. The newly resolved systems include one triple star - G190-10. If combined with spectroscopic and visual data, our results imply a single:binary:triple:quadruple star ratio of 147:64:9:1 for a sample of 221 primary components of halo and thick-disk stars

The slope of the RR Lyrae MV-[Fe/H] relation

We review the available observational data to show that the slope of the RR Lyrae MV–[Fe/H] relation is 0.18¹0.03. The recent claim by Feast that, because of biases, the true slope is much steeper is not justified

The Multiple Origin of Blue Straggler Stars: Theory vs. Observations

In this chapter we review the various suggested channels for the formation and evolution of blue straggler stars (BSSs) in different environments and their observational predictions. These include mass transfer during binary stellar evolution - case A/B/C and D (wind Roche-lobe overflow) mass transfer, stellar collisions during single and binary encounters in dense stellar cluster, and coupled dynamical and stellar evolution of triple systems. We also explore the importance of the BSS and binary dynamics in stellar clusters. We review the various observed properties of BSSs in different environments (halo and bulge BSSs, BSSs in globular clusters and BSSs in old open clusters), and compare the current observations with the theoretical predictions for BSS formation. We try to constrain the likely progenitors and processes that play a role in the formation of BSSs and their evolution. We find that multiple channels of BSS formation are likely to take part in producing the observed BSSs, and we point out the strengths and weaknesses of each the formation channel in respect to the observational constraints. Finally we point out directions to further explore the origin of BSS, and highlight eclipsing binary BSSs as important observational tool.Comment: Chapter 11, in Ecology of Blue Straggler Stars, H.M.J. Boffin, G. Carraro & G. Beccari (Eds), Astrophysics and Space Science Library, Springe