17,414 research outputs found
Cosmic rays in the 10(16) to 10(19) eV range from pulsars
The flux is calculated of cosmic rays (CRs) produced by a distribution of pulsars that are: (1) born with rapid rotation rates, (2) slow down as they evolve, and (3) produce energetic nuclei with a characteristic energy proportional to their rotation rates. It is found that, for energy independent escape from the disk of the galaxy, the predicted spectrum will be essentially what is observed between approx 10 to the 16th power to 10 to the 19 power eV if the slow down law as inferred for radio pulsars can be extrapolated to young pulsars with shorter periods
The effect of surface contamination on contact angles and surface potentials Summary report
Surface contamination effects on behavior of liquids in space vehicle tanks at zero gravit
Risk Taking by Mutual Funds as a Response to Incentives
This paper examines the agency conflict between mutual fund investors and mutual fund companies. Investors would like the fund company to use its judgement to maximize risk-adjusted fund returns. A fund company, however, in its desire to maximize its value as a concern has an incentive to take actions which increase the inflow of investment. We use a semiparametric model to estimate the shape of the flow-performance relationship for a sample of growth and growth and income funds observed over the 1982-1992 period. The shape of the flow-performance relationship creates incentives for fund managers to increase or decrease the riskiness of the fund which are dependent on the fund's year-to-date return. Using a new dataset of mutual fund portfolios which includes equity portfolio holdings for September and December of the same year, we show that mutual funds do alter their portfolio riskiness between September and December in a manner consistent with these risk incentives.
Discovery of 21cm absorption in a DLA towards TXS 0311+430: The first low spin temperature absorber at z > 1
We report the detection of HI 21 cm absorption from the damped
Lyman- system (DLA) towards TXS 0311+430, with the Green Bank
Telescope. The 21 cm absorption has a velocity spread (between nulls) of km s and an integrated optical depth of km s. We also present new Giant Metrewave Radio
Telescope 602 MHz imaging of the radio continuum. TXS 0311+430 is unresolved at
this frequency, indicating that the covering factor of the DLA is likely to be
high. Combining the integrated optical depth with the DLA HI column density of
\nhi = \cm, yields a spin temperature of K, assuming a covering factor of unity. This is the first case of
a low spin temperature ( DLA and is among the lowest
ever measured in any DLA. Indeed, the measured for this DLA is similar to
values measured in the Milky Way and local disk galaxies. We also determine a
lower limit (Si/H) solar for the DLA metallicity, amongst the
highest abundances measured in DLAs at any redshift. Based on low redshift
correlations, the low , large 21 cm absorption width and high metallicity
all suggest that the DLA is likely to arise in a massive,
luminous disk galaxy.Comment: 5 pages, 3 figures. Accepted for publication in MNRAS (Letters
A Search for Boron in Damped Ly{\alpha} Systems
We present the first systematic study of boron beyond the Local Group. This
analysis is performed on a sample of 30 damped Ly{\alpha} systems (DLAs) with
strong metal-lines, which are expected to trace the interstellar medium of high
z galaxies. We report on two boron detections at > 3{\sigma} significance; one
new detection and one confirmation. The ratios of B/O and, for the first time,
B/S are compared with previous stellar and interstellar measurements in the
Milky Way and Small Magellanic Cloud. The novel comparison with sulphur, which
tracks oxygen's abundance, alleviates the uncertainty associated with stellar
oxygen measurements. For both detections, the inferred B/S ratio is in excess
of the prediction of primary boron production from spallation processes.
Possible sources of contamination are discussed, as well as physical effects
that could impact the observed ratios. However taken at face value, the
implication of these measurements suggest potentially higher cosmic ray fluxes
in DLAs. The prospects for future boron detections in other high redshift DLAs
to confirm our results is also discussed.Comment: Accepted for publication in MNRAS, 19 pages, 10 figure
Exploratory studies of contact angle hysteresis, wetting of solidified rare gases and surface properties of mercury Final report
Contact angle hysteresis, wetting of solidified rare gases, and surface properties of mercur
Religion and Attitudes toward Same-Sex Marriage among U.S. Latinos
Objectives. This study examines links between multiple aspects of religious involvement and attitudes toward same-sex marriage among U.S. Latinos. The primary focus is on variations by affiliation and participation, but the possible mediating roles of biblical beliefs, clergy cues, and the role of religion in shaping political views are also considered.
Methods. We use binary logistic regression models to analyze data from a large nationwide sample of U.S. Latinos conducted by the Pew Hispanic Forum in late 2006.
Results. Findings highlight the strong opposition to same-sex marriage among Latino evangelical (or conservative) Protestants and members of sectarian groups (e.g., LDS), even compared with devout Catholics. Although each of the hypothesized mediators is significantly linked with attitudes toward same-sex marriage, for the most part controlling for them does not alter the massive affiliation/attendance differences in attitudes toward same-sex marriage.
Conclusions. This study illustrates the importance of religious cleavages in public opinion on social issues within the diverse U.S. Latino population. The significance of religious variations in Hispanic civic life is likely to increase with the growth of the Latino population and the rising numbers of Protestants and sectarians among Latinos
Wind tunnel buffet load measuring technique
Indirect force measurement technique estimates unsteady forces acting on elastic model during wind tunnel tests. Measurement of forces is practically insensitive to errors in aeroelastic scaling between model and full-scale structure, simplifying design, fabrication and dynamic calibration
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