1,190 research outputs found
The Effect of Normative and Behavioral Persuasion on Help-Seeking in Thai and American College Students
Based on previous research on self-construals, the theory of reasoned action, and persuasive communication, we hypothesized that individual, behavioral-focused information would be more effective in increasing help-seeking intention among college students in the United States, whereas relational, normative-focused information would be more effective among college students in Thailand. Results partially supported these predictions suggesting that differing information can enhance help-seeking intention across cultures
Aerosol perturbations related to volcanic eruptions during the past few centuries as recorded in an ice core from the Central Dronning Maud Land, Antarctica
High-resolution glacio-chemical analyses were carried out in a 62.2 m long ice core recovered from the Central Dronning Maud Land, East Antarctica, to evaluate temporal changes in environmental characteristics during the past five centuries. The sulphate (SO 4 2-) content within the core varied between 15 and 377 ppb, whereas the sodium (Na +) and chloride (Cl -) content fluctuated widely from 7 to 500 ppb and 25 to 1461 ppb respectively. The computed non-sea-salt sulphate (nssSO 4 2-) record reveals the existence of several outstanding peaks that can be attributed to the sulphate aerosol deposition during large volcanic events as recorded in Antarctica and elsewhere. Major volcanic events identified at the core site include: Mt Pinatubo (1991), Agung (1963), Krakatau/Tarawera (1883/1886), Tambora (1815) and Huaynaputina (1600) among several other moderate events. Comparison of our nssSO 4 2- record with that of ice core records from Greenland reveals analogous sulphate deposition during certain major volcanic events, demonstrating the interhemispheric transport of aerosols during large volcanic eruptions. Relatively high Cl -/Na + ratio throughout the core (mean 3.1) compared to that of the sea water ratio implies additional sources of Cl -, most likely due to the intense scavenging of gaseous Cl - in the lower atmosphere
Analysis of the third national health and nutrition examination survey (NHANES III) using expert ratings of job categories
Background Few epidemiologic studies have addressed the exposure–response relationships between work activities and symptomatic knee osteoarthritis (OA). This analysis used data from a national survey and ergonomists' ratings to address this issue. Methods Interview and knee X-ray data were obtained from the Third National Health and Nutrition Examination Survey. Occupational ratings were obtained using ergonomists. A weighted logistic regression was used. Results Among men, a significant exposure–response relationship was found between symptomatic knee OA and kneeling. In both genders, there was a significant trend in heavy lifting and severe symptomatic knee OA. Approximately 20.7% of knee OA can be attributed to kneeling >14% of the workday among men. Conclusions The significant exposure–response relationships suggest that modest reductions in certain occupational activities can reduce the burden of knee OA. The study was limited by unvalidated expert ratings. Research is needed to identify hazardous characteristics of work activities and to clarify exposure–response relationships. Am. J. Ind. Med. 51:37–46, 2008. © 2007 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57516/1/20512_ftp.pd
Correlated multiplexity and connectivity of multiplex random networks
Nodes in a complex networked system often engage in more than one type of
interactions among them; they form a multiplex network with multiple types of
links. In real-world complex systems, a node's degree for one type of links and
that for the other are not randomly distributed but correlated, which we term
correlated multiplexity. In this paper we study a simple model of multiplex
random networks and demonstrate that the correlated multiplexity can
drastically affect the properties of giant component in the network.
Specifically, when the degrees of a node for different interactions in a duplex
Erdos-Renyi network are maximally correlated, the network contains the giant
component for any nonzero link densities. In contrast, when the degrees of a
node are maximally anti-correlated, the emergence of giant component is
significantly delayed, yet the entire network becomes connected into a single
component at a finite link density. We also discuss the mixing patterns and the
cases with imperfect correlated multiplexity.Comment: Revised version, 12 pages, 6 figure
Pterodactyl: Trade Study for an Integrated Control System Design of a Mechanically Deployable Entry Vehicle
This paper presents the trade study method used to evaluate and downselect from a set of guidance and control (G&C) system designs for a mechanically Deployable Entry Vehicle (DEV). The Pterodactyl project was prompted by the challenge to develop an effective G&C system for a vehicle without a backshell, which is the case for DEVs. For the DEV, the project assumed a specific aeroshell geometry pertaining to an Adaptable, Deployable Entry and Placement Technology (ADEPT) vehicle, which was successfully developed by NASAs Space Technology Mission Directorate (STMD) prior to this study. The Pterodactyl project designed three different entry G&C systems for precision targeting. This paper details the Figures of Merit (FOMs) and metrics used during the course of the projects G&C system assessment. The relative importance of the FOMs was determined from the Analytic Hierarchy Process (AHP), which was used to develop weights that were combined with quantitative design metrics and engineering judgement to rank the G&C systems against one another. This systematic method takes into consideration the projects input while simultaneously reducing unintentional judgement bias and ultimately was used to select a single G&C design for the project to pursue in the next design phase
Mycotic aneurysm of the posterior tibial artery – a rare complication of bacterial endocarditis: a case report
<p>Abstract</p> <p>Introduction</p> <p>Distal arterial embolisation and subsequent aneurysm formation are rare occurrences and most are secondary to trauma. We have found no case reports that describe posterior tibial aneurysm formation secondary to bacterial endocarditis.</p> <p>Case presentation</p> <p>We report the case of a 47-year-old Caucasian man who, 2 years after an episode of subacute bacterial endocarditis, presented with signs and symptoms consistent with posterior tibial aneurysm formation.</p> <p>Conclusion</p> <p>Posterior tibial aneurysm formation is a rare occurrence, most commonly occurring after trauma and, although other causes have been described, to our knowledge, endocarditis has not been implicated before, and as such should therefore be borne in mind when dealing with cases where no obvious aetiology is evident.</p
Risk of radiation-induced second malignant neoplasms from photon and proton radiotherapy in paediatric abdominal neuroblastoma
Background and Purpose: State-of-the-art radiotherapy modalities have the potential of reducing late effects of treatment in childhood cancer survivors. Our aim was to investigate the carcinogenic risk associated with 3D conformal (photon) radiation (3D-CRT), intensity modulated arc therapy (IMAT) and pencil beam scanning proton therapy (PBS-PT) in the treatment of paediatric abdominal neuroblastoma.
Materials and Methods: The risk of radiation-induced second malignant neoplasm (SMN) was estimated using the concept of organ equivalent dose (OED) for eleven organs (lungs, rectum, colon, stomach, small intestine, liver, bladder, skin, central nervous system (CNS), bone, and soft tissues). The risk ratio (RR) between radiotherapy modalities and lifetime absolute risks (LAR) were reported for twenty abdominal neuroblastoma patients (median, 4y; range, 1-9y) historically treated with 3D-CRT that were also retrospectively replanned for IMAT and PBS-PT.
Results: The risk of SMN due to primary radiation was reduced in PBS-PT against 3D-CRT and IMAT for most patients and organs. The RR across all organs ranged from 0.38 ± 0.22 (bladder) to 0.98 ± 0.04 (CNS) between PBS-PT and IMAT, and 0.12 ± 0.06 (rectum and bladder) to 1.06 ± 0.43 (bone) between PBS-PT and 3D-CRT. The LAR for most organs was within 0.01–1% (except the colon) with a cumulative risk of 21 ± 13%, 35 ± 14% and 35 ± 16% for PBS-PT, IMAT and 3D-CRT, respectively.
Conclusions: PBS-PT was associated with the lowest risk of radiation-induced SMN compared to IMAT and 3D-CRT in abdominal neuroblastoma treatment. Other clinical endpoints and plan robustness should also be considered for optimal plan selection
Constraining the assembly time of the stellar haloes of nearby Milky Way-mass galaxies through AGB populations
The star formation histories (SFHs) of galactic stellar haloes offer crucial
insights into the merger history of the galaxy and the effects of those mergers
on their hosts. Such measurements have revealed that while the Milky Way's most
important merger was 8-10 Gyr ago, M31's largest merger was more recent, within
the last few Gyr. Unfortunately, the required halo SFH measurements are
extremely observationally expensive outside of the Local Group. Here we use
asymptotic giant branch (AGB) stars brighter than the tip of the red giant
branch (RGB) to constrain stellar halo SFHs. Both stellar population models and
archival datasets show that the AGB/RGB ratio constrains the time before which
90% of the stars formed, . We find AGB stars in the haloes of three
highly-inclined roughly Milky Way-mass galaxies with resolved star measurements
from the Hubble Space Telescope; this population is most prominent in the
stellar haloes of NGC 253 and NGC 891, suggesting that their stellar haloes
contain stars born at relatively late times, with inferred Gyr. This ratio also varies from region to region, tending towards
higher values along the major axis and in tidal streams or shells. By combining
our measurements with previous constraints, we find a tentative anticorrelation
between halo age and stellar halo mass, a trend that exists in models of galaxy
formation but has never been elucidated before, i.e, the largest stellar haloes
of Milky-Way mass galaxies were assembled more recently.Comment: 20 Pages, 10 Figure
Is NGC 300 a pure exponential disk galaxy?
NGC 300 is a low-mass disk galaxy in the Sculptor group. In the literature,
it has been identified as a pure exponential disk galaxy, as its luminosity
profile could be well fitted with a single exponential law over many disk scale
lengths (Type I). We investigate the stellar luminosity distribution of NGC 300
using (HST) archive data, reaching farther and
deeper than any other previous studies. Color magnitude diagrams show a
significant population of old red giant branch (RGB) stars in all fields out to
kpc (), as well as younger populations in the inner regions. We
construct the density profiles of the young, intermediate-aged, and old stellar
populations. We find two clear breaks in the density profiles of the old RGB
and intermediate-aged stars: one down-bending (Type II) at kpc, and
another up-bending (Type III) at kpc. Moreover, the old RGB stars
exhibit a negative radial color gradient with an up-bending at ~kpc,
beyond which the stellar populations are uniformly old (7~Gyr) and
metal-poor ( dex). The outer stellar component
at kpc is, therefore, well separated from the inner disk in
terms of the stellar density and stellar populations. While our results cast
doubt on the currently established wisdom that NGC\,300 is a pure exponential
disk galaxy, a more detailed survey should be carried out to identify the
outskirts as either a disk or a stellar halo.Comment: 6 pages, 5 figures, 1 appendix, accepted for publication in A&A
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