2,110 research outputs found
Gender as a Moderator of the Relationship Between Preparty Motives and Event-Level Consequences
Prepartying is often associated with increased alcohol consumption and negative alcohol-related consequences among college students. General drinking motives are often only weakly related to preparty alcohol use, and few studies have examined the associations between preparty-specific drinking motives and alcohol-related consequences that occur during or after a preparty event. The current study utilizes event-level data to address this gap in the literature by examining the relationship between four types of preparty motives (prepartying to relax or loosen up, to increase control over alcohol use, to meet a dating partner, and to address concerns that alcohol may not be available later) and alcohol consequences as a function of gender. Participants (N = 952) reported on their most recent preparty event in the past month. After controlling for general drinking motives, all four preparty motives predicted greater event-level consequences for both males and females. Further, prepartying to increase control over alcohol consumed was associated with greater consequences for males as compared to females. The findings are consistent with research suggesting that preparty specific motives may further our understanding of prepartying outcomes over and above the use of general drinking motive measures
The population of propellers in Saturn's A Ring
We present an extensive data set of ~150 localized features from Cassini
images of Saturn's Ring A, a third of which are demonstrated to be persistent
by their appearance in multiple images, and half of which are resolved well
enough to reveal a characteristic "propeller" shape. We interpret these
features as the signatures of small moonlets embedded within the ring, with
diameters between 40 and 500 meters. The lack of significant brightening at
high phase angle indicates that they are likely composed primarily of
macroscopic particles, rather than dust. With the exception of two features
found exterior to the Encke Gap, these objects are concentrated entirely within
three narrow (~1000 km) bands in the mid-A Ring that happen to be free from
local disturbances from strong density waves. However, other nearby regions are
similarly free of major disturbances but contain no propellers. It is unclear
whether these bands are due to specific events in which a parent body or bodies
broke up into the current moonlets, or whether a larger initial moonlet
population has been sculpted into bands by other ring processes.Comment: 31 pages, 10 figures; Accepted at A
DUSTiER (DUST in the Epoch of Reionization): dusty galaxies in cosmological radiation-hydrodynamical simulations of the Epoch of Reionization with RAMSES-CUDATON
In recent years, interstellar dust has become a crucial topic in the study of
the high and very high redshift Universe. Evidence points to the existence of
high dust masses in massive star forming galaxies already during the Epoch of
Reionization, potentially affecting the escape of ionising photons into the
intergalactic medium. Moreover, correctly estimating dust extinction at UV
wavelengths is essential for precise ultra-violet luminosity function (UVLF)
prediction and interpretation. In this paper, we investigate the impact of dust
on the observed properties of high redshift galaxies, and cosmic reionization.
To this end, we couple a physical model for dust production to the fully
coupled radiation-hydrodynamics cosmological simulation code RAMSES-CUDATON,
and perform a , , simulation, that we call DUSTiER for DUST in
the Epoch of Reionization. It yields galaxies with dust masses and UV slopes
compatible with constraints at z . We find that extinction has a
dramatic impact on the bright end of the UVLF, even as early as , and
our dusty UVLFs are in better agreement with observations than dust-less UVLFs.
The fraction of obscured star formation rises up to 55% at , in
agreement with some of the latest results from ALMA. Finally, we find that dust
reduces the escape of ionising photons from galaxies more massive than (brighter than MAB1600) by >10%, and possibly up to
80-90% for our most massive galaxies. Nevertheless, we find that the ionising
escape fraction is first and foremost set by neutral Hydrogen in galaxies, as
the latter produces transmissions up to 100 times smaller than through dust
alone.Comment: submitted to MNRAS, 1st report received: under revision Have
partially addressed referee's concerns, namely that the model predicts high
dust masses and redder bright galaxies than expected, by discussing this
aspect around the relevant results. Work is being carried out to present a
clearer parameter exploration of the dust mode
Prevalence and Level of Enterohemorrhagic \u3ci\u3eEscherichia coli\u3c/i\u3e in Culled Dairy Cows at Harvest
The primary objective of this study was to determine the prevalence and level of enterohemorrhagic Escherichia coli (EHEC) O26, O45, O103, O111, O121, and O145 (collectively EHEC-6) plus EHEC O157 in fecal, hide, and preintervention carcass surface samples from culled dairy cows. Matched samples (n=300) were collected from 100 cows at harvest and tested by a culture-based method and two molecular methods: NeoSEEK STEC (NS) and Atlas STEC EG2 Combo. Both the culture and NS methods can be used to discriminate among the seven EHEC types (EHEC-7), from which the cumulative prevalence was inferred, whereas the Atlas method can discriminate only between EHEC O157 and non-O157 EHEC, without discrimination of the serogroup. The EHEC-7 prevalence in feces, hides, and carcass surfaces was 6.5, 15.6, and 1.0%, respectively, with the culture method and 25.9, 64.9, and 7.0%, respectively, with the NS method. With the Atlas method, the prevalence of non-O157 EHEC was 29.1, 38.3, and 28.0% and that of EHEC O157 was 29.1, 57.0, and 3.0% for feces, hides, and carcasses, respectively. Only two samples (a hide sample and a fecal sample) originating from different cows contained quantifiable EHEC. In both samples, the isolates were identified as EHEC O157, with 4.7 CFU/1,000 cm2 in the hide sample and 3.9 log CFU/g in the fecal sample. Moderate agreement was found between culture and NS results for detection of EHEC O26 (k=0.58,
NICMOS and VLA Observations of the Gravitatonally Lensed Ultraluminous BAL Quasar APM~08279+5255: Detection of a Third Image
We present a suite of observations of the recently identified ultraluminous
BAL quasar APM 08279+5255, taken both in the infra-red with the NICMOS high
resolution camera on board the Hubble Space Telescope, and at 3.5cm with the
Very Large Array. With an inferred luminosity of ~5x10^15 Solar luminosities,
APM 08279+5255 is apparently the most luminous system known. Extant
ground-based images show that APM 08279+5255 is not point-like, but is instead
separated into two components, indicative of gravitational lensing. The much
higher resolution images presented here also reveal two point sources, A and B,
of almost equal brightness (f_B/f_A=0.782 +/- 0.010), separated by 0."378 +/-
0."001, as well as a third, previously unknown, fainter image, C, seen between
the brighter images. While the nature of C is not fully determined, several
lines of evidence point to it being a third gravitationally lensed image of the
quasar, rather than being the lensing galaxy. Simple models which recover the
relative image configuration and brightnesses are presented. While proving to
be substantially amplified, APM 08279+5255 possesses an intrinsic bolometric
luminosity of ~10^14 to 10^15 Solar luminosities and remains amongst the most
luminous objects known.Comment: 21 pages, 5 figures (2 as GIF files); accepted for publication in the
Astronomical Journa
Internet All Nation Breath of life (I-ANBL) a Tribal College Student Engaged Development of an Internet-based Smoking Cessation Intervention
Background: Compared to non-Hispanic white college students, American Indian (AI) tribal college students have the highest smoking prevalence in the U.S. (~34%). Culturally-tailored smoking cessation programs have proven to be successful in reducing smoking rates but may require new methods to reach college students. Currently, there is little documentation on the development and success of Internet-based smoking interventions for AI tribal college students.
Objectives: To develop an Internet-based smoking cessation program (Internet-All Nations Breath of Life or I-ANBL) with tribal college students.
Methods: We conducted six focus groups (n=41) at a tribal college. Focus groups included tribal college students who smoked and groups were stratified by sex. Transcripts were analyzed using insider and outsider perspectives. After analysis, an Internet-based smoking cessation program was developed, based on insight gained.
Results: Numerous suggestions for creating the program were offered. There was consensus on the need for a variety of visuals including cultural images, videos, and interactive content. The students also suggested the integration of familiar platforms such as FacebookTM.
Conclusion: When culturally tailoring a web-based smoking cessation program for tribal college students, it is important to incorporate cultural aspects and recognize gender differences. One important aspect is to recognize that for many AI, tobacco is a sacred plant and images of tobacco should be respectful. Now that this intervention has been developed, next we will test it for efficacy in a randomized controlled trial.
Keywords: American Indians, tribal college, tobacco, program development, smoking cessation, community-based participatory researc
Solving geoinformatics parametric polynomial systems using the improved Dixon resultant
Improvements in computational and observational technologies in geoinformatics, e.g., the use of laser scanners that produce huge point cloud data sets, or the proliferation of global navigation satellite systems (GNSS) and unmanned aircraft vehicles (UAVs), have brought with them the challenges of handling and processing this “big data”. These call for improvement or development of better processing algorithms. One way to do that is integration of symbolically presolved sub-algorithms to speed up computations. Using examples of interest from real geoinformatic problems, we will discuss the Dixon-EDF resultant as an improved resultant method for the symbolic solution of parametric polynomial systems. We will briefly describe the method itself, then discuss geoinformatics problems arising in minimum distance mapping (MDM), parameter transformations, and pose estimation essential for resection. Dixon-EDF is then compared to older notions of “Dixon resultant”, and to several respected implementations of Gröbner bases algorithms on several systems. The improved algorithm, Dixon-EDF, is found to be greatly superior, usually by orders of magnitude, in both CPU usage and RAM usage. It can solve geoinformatics problems on which the other methods fail, making symbolic solution of parametric systems feasible for many problems
Cosmic Variance and the Inhomogeneous UV Luminosity Function of Galaxies During Reionization
When the first galaxies formed and starlight escaped into the intergalactic
medium to reionize it, galaxy formation and reionization were both highly
inhomogeneous in time and space, and fully-coupled by mutual feedback. To show
how this imprinted the UV luminosity function (UVLF) of reionization-era
galaxies, we use our large-scale, radiation-hydrodynamics simulation CoDa II to
derive the time- and space-varying halo mass function and UVLF, from
-15. That UVLF correlates strongly with local reionization redshift:
earlier-reionizing regions have UVLFs that are higher, more extended to
brighter magnitudes, and flatter at the faint end than later-reionizing regions
observed at the same . In general, as a region reionizes, the faint-end
slope of its local UVLF flattens, and, by (when reionization ended), the
global UVLF, too, exhibits a flattened faint-end slope, `rolling-over' at
. CoDa II's UVLF is broadly consistent with
cluster-lensed galaxy observations of the Hubble Frontier Fields at -8,
including the faint end, except for the faintest data point at , based on
one galaxy at . According to CoDa II, the probability of
observing the latter is . However, the effective volume searched at
this magnitude is very small, and is thus subject to significant cosmic
variance. We find that previous methods adopted to calculate the uncertainty
due to cosmic variance underestimated it on such small scales by a factor of
2-4, primarily by underestimating the variance in halo abundance when the
sample volume is small.Comment: 16 pages, 16 figures, accepted by MNRAS 07/20/23, comments welcom
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
Extensive Liquid Meltwater Storage in Firn Within the Greenland Ice Sheet
The accelerating loss of mass from the Greenland ice sheet is a major contribution to current sea level rise. Increased melt water runoff is responsible for half of Greenlands mass loss increase. Surface melt has been increasing in extent and intensity, setting a record for surface area melt and runoff in 2012. The mechanisms and timescales involved in allowing surface melt water to reach the ocean where it can contribute to sea level rise are poorly understood. The potential capacity to store this water in liquid or frozen form in the firn (multi-year snow layer) is significant, and could delay its sea-level contribution. Here we describe direct observation of water within a perennial firn aquifer persisting throughout the winter in the southern ice sheet,where snow accumulation and melt rates are high. This represents a previously unknown storagemode for water within the ice sheet. Ice cores, groundairborne radar and a regional climatemodel are used to estimate aquifer area (70 plue or minus 10 x 10(exp 3) square kilometers ) and water table depth (5-50 m). The perennial firn aquifer represents a new glacier facies to be considered 29 in future ice sheet mass 30 and energy budget calculations
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