424 research outputs found
Fostering Diverse Friendships: The Role of Beliefs about the Value of Diversity
Encouraging dialogue between people of differing social backgrounds and beliefs can reduce prejudice and lead to greater appreciation of diversity, which in turn fosters attitudinally diverse friendships. We investigated how beliefs about the value of diversity relate to attitudinal diversity within relationship dyads. In a field study of naturally occurring relationship pairs in two neighborhoods of Boston (N = 89 dyads), participants completed measures of diversity beliefs and sociopolitical attitudes. People placed higher value on diversity in the Jamaica Plain neighborhood compared to people in the North End neighborhood, and relationship pairs were more attitudinally diverse in Jamaica Plain than in the North End. Attitudinal diversity within pairs was predicted by how highly the pair jointly valued diversity. Further, pairs’ greater valuing of diversity in Jamaica Plain mediated the effect of neighborhood on attitude diversity. These findings suggest that individual differences in appreciation for diversity are meaningful predictors of diverse relationships
The alignment of the polarization of HAe/Be stars with the interstellar magnetic field
We present a study of the correlation between the direction of the symmetry
axis of the circumstellar material around intermediate mass young stellar
objects and that of the interstellar magnetic field. We use CCD polarimetric
data on 100 Herbig Ae/Be stars. A large number of them shows intrinsic
polarization, which indicates that their circumstellar envelopes are not
spherical. The interstellar magnetic field direction is estimated from the
polarization of field stars. There is an alignment between the position angle
of the Herbig Ae/Be star polarization and that of the field stars for the most
polarized objects. This may be an evidence that the ambient interstellar
magnetic field plays a role in shaping the circumstellar material around young
stars of intermediate mass and/or in defining their angular momentum axis.Comment: ApJ accepte
A Chandra ACIS Study of the Young Star Cluster Trumpler 15 in Carina and Correlation with Near-infrared Sources
Using the highest-resolution X-ray observation of the Trumpler 15 star
cluster taken by the Chandra X-ray Observatory, we estimate the total size of
its stellar population by comparing the X-ray luminosity function of the
detected sources to a calibrator cluster, and identify for the first time a
significant fraction (~14%) of its individual members. The highest-resolution
near-IR observation of Trumpler 15 (taken by the HAWK-I instrument on the VLT)
was found to detect most of our X-ray selected sample of cluster members, with
a K-excess disk frequency of 3.8+-0.7%. The near-IR data, X-ray luminosity
function, and published spectral types of the brightest members support a
cluster age estimate (5-10 Myr) that is older than those for the nearby
Trumpler 14 and Trumpler 16 clusters, and suggest that high-mass members may
have already exploded as supernovae. The morphology of the inner ~0.7 pc core
of the cluster is found to be spherical. However, the outer regions (beyond 2
pc) are elongated, forming an `envelope' of stars that, in projection, appears
to connect Trumpler 15 to Trumpler 14; this morphology supports the view that
these clusters are physically associated. Clear evidence of mass segregation is
seen. This study appears in a Special Issue of the ApJS devoted to the Chandra
Carina Complex Project (CCCP), a 1.42 square degree Chandra X-ray survey of the
Great Nebula in Carina.Comment: Accepted for the ApJS Special Issue on the Chandra Carina Complex
Project (CCCP), scheduled for publication in May 2011. All 16 CCCP Special
Issue papers are available at
http://cochise.astro.psu.edu/Carina_public/special_issue.html through 2011 at
least. 30 pages; 8 figures; 3 table
Magnetism, rotation and accretion in Herbig Ae-Be stars
Studies of stellar magnetism at the pre-main sequence phase can provide
important new insights into the detailed physics of the late stages of star
formation, and into the observed properties of main sequence stars. This is
especially true at intermediate stellar masses, where magnetic fields are
strong and globally organised, and therefore most amenable to direct study.
This talk reviews recent high-precision ESPaDOnS observations of pre-main
sequence Herbig Ae-Be stars, which are yielding qualitatively new information
about intermediate-mass stars: the origin and evolution of their magnetic
fields, the role of magnetic fields in generating their spectroscopic activity
and in mediating accretion in their late formative stages, and the factors
influencing their rotational angular momentum.Comment: 8 page
Increased risk for a second retroviral infection (SIV or STLV type 1) for wild African green monkeys already infected by one retrovirus in Senegal (West Africa)
Photostatistics Reconstruction via Loop Detector Signatures
Photon-number resolving detectors are a fundamental building-block of optical
quantum information processing protocols. A loop detector, combined with
appropriate statistical processing, can be used to convert a binary on/off
photon counter into a photon-number-resolving detector. Here we describe the
idea of a signature of photon-counts, which may be used to more robustly
reconstruct the photon number distribution of a quantum state. The methodology
is applied experimentally in a 9-port loop detector operating at a
telecommunications wavelength and compared directly to the approach whereby
only the number of photon-counts is used to reconstruct the input distribution.
The signature approach is shown to be more robust against calibration errors,
exhibit reduced statistical uncertainty, and reduced reliance on a-priori
assumptions about the input state.Comment: 13 pages, 12 figure
SearchCal: a Virtual Observatory tool for searching calibrators in optical long baseline interferometry. I: The bright object case
In long baseline interferometry, the raw fringe contrast must be calibrated
to obtain the true visibility and then those observables that can be
interpreted in terms of astrophysical parameters. The selection of suitable
calibration stars is crucial for obtaining the ultimate precision of
interferometric instruments like the VLTI. We have developed software SearchCal
that builds an evolutive catalog of stars suitable as calibrators within any
given user-defined angular distance and magnitude around the scientific target.
We present the first version of SearchCal dedicated to the bright-object case
V<=10; K<=5). Star catalogs available at the CDS are consulted via web
requests. They provide all the useful information for selecting of calibrators.
Missing photometries are computed with an accuracy of 0.1 mag and the missing
angular diameters are calculated with a precision better than 10%. For each
star the squared visibility is computed by taking the wavelength and the
maximum baseline of the foreseen observation into account.} SearchCal is
integrated into ASPRO, the interferometric observing preparation software
developed by the JMMC, available at the address: http://mariotti.fr
A FEROS spectroscopic study of the extreme O supergiant He 3-759
We present a study of the extreme O-type supergiant He 3-759 using new
high-resolution FEROS data, revealing that it is a near spectroscopic twin of
HD 151804 (O8 Iaf). We investigate the extinction towards He 3-759 using a
variety of methods, revealing A_V ~ 4.7 mag. If we assume He 3-759 has an
identical absolute K-band magnitude to HD 151804 we find that it lies in the
Sagittarius-Carina spiral arm at a distance of ~6.5 kpc. We derive the physical
and wind properties for He 3-759, revealing T* = 30.5 kK, log L/L(sun) = 5.9
and dM/dt = 10^-5.17 M(sun)/yr for a clumped wind whose terminal velocity is
estimated at 1000 km/s. The atmosphere of He 3-759 is enriched in helium (X_He
= 49%) and nitrogen (X_N = 0.3%). A reanalysis of HD 151804 and HD 152408
(WN9ha) reveals similar parameters except that the WN9ha star possesses a
stronger wind and reduced surface hydrogen content. HD 151804 and HD 152408 lie
within the Sco OB1 association, with initial masses of ~60 M(sun) and ages ~2.7
Myr, consistent with NGC 6231 cluster members using standard Geneva isochrones.
Improved agreement with observed surface abundances are obtained for similar
initial masses with more recent Geneva group predictions from which higher ages
of ~3.75 Myr are obtained. No young, massive star cluster is known to be
associated with He 3-759.Comment: 6 pages, 4 figures, accepted for A&
Isolation and molecular characterization of a human T-cell lymphotropic virus type 2 (HTLV-2), subtype B, from a healthy Pygmy living in a remote area of Cameroon : an ancient origin for HTLV-2 in Africa
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