5,730 research outputs found
Alien Registration- Curran, W J. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/24367/thumbnail.jp
Alien Registration- Curran, W J. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/24367/thumbnail.jp
The application of satellite data in the determination of ocean temperatures and cloud characteristics and statistics
The author has identified the following significant results. The major shortcoming of the data was the loss of the infrared radiances from the S191 spectrometer. The cloud thermodynamic phase determination procedure was derived and tested with the data collected by the S192 multispectral scanner. Results of the test indicate a large fraction of the data could be classified thermodynamically. An added bonus was the inclusion of snow in the classification approach. The conclusion to be drawn from this portion of the effort is that in most cases considered ice clouds, liquid water droplet clouds, and snow fields can be spectroscopically separated to a high degree of accuracy
Using 21-cm absorption surveys to measure the average HI spin temperature in distant galaxies
We present a statistical method for measuring the average HI spin temperature
in distant galaxies using the expected detection yields from future wide-field
21cm absorption surveys. As a demonstrative case study we consider a simulated
all-southern-sky survey of 2-h per pointing with the Australian Square
Kilometre Array Pathfinder for intervening HI absorbers at intermediate
cosmological redshifts between and . For example, if such a survey
yielded absorbers we would infer a harmonic-mean spin temperature of
K for the population of damped Lyman
(DLAs) absorbers at these redshifts, indicating that more than
per cent of the neutral gas in these systems is in a cold neutral medium (CNM).
Conversely, a lower yield of only 100 detections would imply
K and a CNM fraction less than per
cent. We propose that this method can be used to provide independent
verification of the spin temperature evolution reported in recent 21cm surveys
of known DLAs at high redshift and for measuring the spin temperature at
intermediate redshifts below , where the Lyman- line is
inaccessible using ground-based observatories. Increasingly more sensitive and
larger surveys with the Square Kilometre Array should provide stronger
statistical constraints on the average spin temperature. However, these will
ultimately be limited by the accuracy to which we can determine the HI column
density frequency distribution, the covering factor and the redshift
distribution of the background radio source population.Comment: 11 pages, 9 figures, 1 table. Proof corrected versio
Corporate social responsibility:reviewed, rated, revised
Purpose: Critical literature review of CSR research in both general management and hospitality management literature. Discusses trends,commonalities, and inconsistencies to better understand the state of contemporary scholarship, and calls for a context-specific conceptual engagement with the phenomenon.Design/Methodology/Approach: Systematic literature review, noting and critiquing a general tendency towards measurement of financial and other internal benefit impacts.Findings: Hospitality management is well-positioned to evaluate the opportunities and challenges of CSR, yet research has uncritically adopted the instrumental emphasis on assessing processes, perceptions, and private profitability from the general management literature, without engaging on a contextually-specific and/or theoretical level.Research limitations: CSR research is abundant and therefore difficult to summarise in one article.The primarily Anglo-American and Asian contextual bias is reflected in this review.Practical implications: Consistently inconsistent results challenge the portability of financial impact studies.Studies are needed to re-evaluate the concept of CSR as it pertains to hospitality, and measure the effectiveness of CSR activities relative to context and resource availability.Social implications: Further research into the scope of CSR in hospitality management, with an emphasis on recuperating social value, would lead to widespread positive social implications.Originality/value: This critical review offers a new perspective on CSR in the hospitality literature and industry, calling for a reconsideration of the concept in context, and formulates a working definition
System configuration and executive requirements specifications for reusable shuttle and space station/base
System configuration and executive requirements specifications for reusable shuttle and space station/bas
Ultra-violet photo-ionisation in far-infrared selected sources
It has been reported that there is a deficit of stellar heated dust, as
evident from the lack of far-infrared (FIR) emission, in sources within the
Herschel-SPIRE sample with X-ray luminosities exceeding a ``critical value'' of
L~10^37 W. Such a scenario would be consistent with the suppression of star
formation by the AGN, required by current theoretical models. Since absorption
of the 21-cm transition of neutral hydrogen (HI), which traces the star-forming
reservoir, also exhibits a critical value in the ultra-violet band (above
ionising photon rates of Q ~ 3 x 10^56 s^-1), we test the SPIRE sample for the
incidence of the detection of 250 micron emission with Q. The highest value at
which FIR emission is detected above the SPIRE confusion limit is Q = 8.9 x
10^57 s^-1, which is ~30 times that for the HI, with no critical value
apparent. Since complete ionisation of the neutral atomic gas is expected at Q
> 3 x 10^56 s-1., this may suggest that much of the FIR must arise from heating
of the dust by the AGN. However, integrating the ionising photon rate of each
star over the initial mass function, we cannot rule out that the high observed
ionising photon rates are due to a population of hot, massive stars.Comment: Accepted by A&
Rotation in the Orion Nebula Cluster
Eighteen fields in the Orion Nebula Cluster (ONC) have been monitored for one
or more observing seasons from 1990-99 with a 0.6-m telescope at Wesleyan
University. Photometric data were obtained in Cousins I on 25-40 nights per
season. Results from the first 3 years of monitoring were analyzed by Choi &
Herbst (1996; CH). Here we provide an update based on 6 more years of
observation and the extensive optical and IR study of the ONC by Hillenbrand
(1997) and Hillenbrand et al. (1998). Rotation periods are now available for
134 ONC members. Of these, 67 were detected at multiple epochs with identical
periods by us and 15 more were confirmed by Stassun et al. (1999) in their
study of Ori OBIc/d. The bimodal period distribution for the ONC is confirmed,
but we also find a clear dependence of rotation period on mass. This can be
understood as an effect of deuterium burning, which temporarily slows the
contraction and thus spin-up of stars with M <0.25 solar masses and ages of ~1
My. Stars with M <0.25 solar masses have not had time to bridge the gap in the
period distribution at ~4 days. Excess H-K and I-K emission, as well as CaII
infrared triplet equivalent widths (Hillenbrand et al. 1998), show weak but
significant correlations with rotation period among stars with M >0.25 solar
masses. Our results provide new observational support for the importance of
disks in the early rotational evolution of low mass stars. [abridged]Comment: 18 pages of text, 17 figures, and 4 tables; accepted for publication
in The Astronomical Journa
Further Observational Evidence for a Critical Ionising Luminosity in Active Galaxies
We report the results of a survey for HI 21-cm absorption at redshifts of z >
2.6 in a new sample of radio sources with the Green Bank and Giant Metrewave
Radio Telescopes. From a total of 25 targets, we report zero detections in the
16 for which optical depth limits could be obtained. Based upon the detection
rate for z > 0.1 associated absorption, we would expect approximately four
detections. Of the 11 which have previously not been searched, there is
sufficient source-frame optical/ultra-violet photometry to determine the
ionising photon rate for four. Adding these to the literature, the hypothesis
that there is a critical rate of logQ = 56 ionising photons per second is now
significant at ~7 sigma. This reaffirms our assertion that searching z > 3
active galaxies for which optical redshifts are available selects sources in
which the ultra-violet luminosity is sufficient to ionise all of the neutral
gas in the host galaxy.Comment: Accepted by MNRA
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