5,651 research outputs found
Astrobiological Effects of F, G, K and M Main-Sequence Stars
We focus on the astrobiological effects of photospheric radiation produced by
main-sequence stars of spectral types F, G, K, and M. The photospheric
radiation is represented by using realistic spectra, taking into account
millions or hundred of millions of lines for atoms and molecules. DNA is taken
as a proxy for carbon-based macromolecules, assumed to be the chemical
centerpiece of extraterrestrial life forms. Emphasis is placed on the
investigation of the radiative environment in conservative as well as
generalized habitable zones.Comment: 3 pages, 3 figures; submitted to: Exoplanets: Detection, Formation
and Dynamics, IAU Symposium 249, eds. Y.S. Sun and S. Ferraz-Mello (San
Francisco: Astr. Soc. Pac.
Profiling the Frequent Clothing Shopper
Frequent shoppers are an important segment of consumers for the clothing industry because they account for a disproportionate amount of sales and profits and play an important role in the fashion diffusion process. The purpose of this study was to test hypothesized characteristics that distinguish frequent shoppers clothing from other buyers. We focused on characteristics that have been studied by previous researchers and characteristics that have received less study, but are no less interesting and potentially important to clothing marketing and management
Striations in the Taurus molecular cloud: Kelvin-Helmholtz instability or MHD waves?
The origin of striations aligned along the local magnetic field direction in
the translucent envelope of the Taurus molecular cloud is examined with new
observations of 12CO and 13CO J=2-1 emission obtained with the 10~m
submillimeter telescope of the Arizona Radio Observatory. These data identify a
periodic pattern of excess blue and redshifted emission that is responsible for
the striations. For both 12CO and 13CO, spatial variations of the J=2-1 to
J=1-0 line ratio are small and are not spatially correlated with the striation
locations. A medium comprised of unresolved CO emitting substructures (cells)
with a beam area filling factor less than unity at any velocity is required to
explain the average line ratios and brightness temperatures. We propose that
the striations result from the modulation of velocities and the beam filling
factor of the cells as a result of either the Kelvin-Helmholtz instability or
magnetosonic waves propagating through the envelope of the Taurus molecular
cloud. Both processes are likely common features in molecular clouds that are
sub-Alfvenic and may explain low column density, cirrus-like features similarly
aligned with the magnetic field observed throughout the interstellar medium in
far-infrared surveys of dust emission.Comment: 11 pages, 4 figures. Accepted for publication in MNRA
Brand Engagement and Consumer Innovativeness
Brand engagement describes the tendency of consumers to make the brands they buy part of their self-concept. This new insight into consumer behavior offers marketers many ways to create relationships with their customers. An unexplored aspect of brand engagement is how it is related to consumer innovativeness, the tendency to be among the first buyers of new products. The present study used survey data from 2399 adult U.S. consumers to show that brand engagement is positively related to consumer innovativeness. This finding suggests that in addition to promoting the features of new products likely to attract innovators, showing how the brand can express the selfconcept of the innovator may also encourage its adoption
A Direct Measurement of the Total Gas Column Density in Orion KL
The large number of high-J lines of C^(18)O available via the Herschel Space Observatory provide an unprecedented ability to model the total CO column density in hot cores. Using the emission from all the observed lines (up to J = 15-14), we sum the column densities in each individual level to obtain the total column after correcting for the population in the unobserved states. With additional knowledge of source size, V_(LSR), and line width, and both local thermodynamic equilibrium (LTE) and non-LTE modeling, we have determined the total C^(18)O column densities in the Extended Ridge, Outflow/Plateau, Compact Ridge, and Hot Core components of Orion KL to be 1.4 × 10^(16) cm^(–2), 3.5 × 10^(16) cm^(–2), 2.2 × 10^(16) cm^(–2), and 6.2 × 10^(16) cm^(–2), respectively. We also find that the C^(18)O/C^(17)O abundance ratio varies from 1.7 in the Outflow/Plateau, 2.3 in the Extended Ridge, 3.0 in the Hot Core, and to 4.1 in the Compact Ridge. This is in agreement with models in which regions with higher ultraviolet radiation fields selectively dissociate C^(17)O, although care must be taken when interpreting these numbers due to the size of the uncertainties in the C^(18)O/C^(17)O abundance ratio
Performance modeling of ultraviolet Raman lidar systems for daytime profiling of atmospheric water vapor
We describe preliminary results from a comprehensive computer model developed to guide optimization of a Raman lidar system for measuring daytime profiles of atmospheric water vapor, emphasizing an ultraviolet, solar-blind approach
The olive biophenols oleuropein and hydroxytyrosol selectively reduce proliferation, influence the cell cycle, and induce apoptosis in pancreatic cancer cells
Current chemotherapy drugs for pancreatic cancer only offer an increase in survival of up to six months. Additionally, they are highly toxic to normal tissues, drastically affecting the quality of life of patients. Therefore, the search for novel agents, which induce apoptosis in cancer cells while displaying limited toxicity towards normal cells, is paramount. The olive biophenols, oleuropein, hydroxytyrosol and tyrosol, have displayed cytotoxicity towards cancer cells without affecting non-tumorigenic cells in cancers of the breast and prostate. However, their activity in pancreatic cancer has not been investigated. Therefore, the aim of this study was to determine the anti-pancreatic cancer potential of oleuropein, hydroxytyrosol and tyrosol. Pancreatic cancer cells (MIA PaCa-2, BxPC-3, and CFPAC-1) and non-tumorigenic pancreas cells (HPDE) were treated with oleuropein, hydroxytyrosol and tyrosol to determine their effect on cell viability. Oleuropein displayed selective toxicity towards MIA PaCa-2 cells and hydroxytyrosol towards MIA PaCa-2 and HPDE cells. Subsequent analysis of Bcl-2 family proteins and caspase 3/7 activation determined that oleuropein and hydroxytyrosol induced apoptosis in MIA PaCa-2 cells, while oleuropein displayed a protective effect on HPDE cells. Gene expression analysis revealed putative mechanisms of action, which suggested that c-Jun and c-Fos are involved in oleuropein and hydroxytyrosol induced apoptosis of MIA PaCa-2 cells
Effects of Acute Stress on Aircrew Performance: Literature Review and Analysis of Operational Aspects
Situational stress can adversely affect the cognition and skilled performance of pilots, as well as experts in other domains. Emergencies and other threatening situations require pilots to execute infrequently practiced procedures correctly and to use their skills and judgment to select an appropriate course of action, often under high workload, time pressure, and ambiguous indications, all of which can be stressful. Our current study, consited of three parts, starting with a critical review of the research literature on the effects of stress on skilled performance, going back to World War II and continuing to recent and more sophisticated studies of the cognitive effects of anxiety. In the second part we analyzed the specific ways stress may have impaired the performance of airline crews in twelve major accidents, selected for diversity of the situations the crews encountered. The third part examined the operational significance and practical implications of the findings from the first two parts, suggested specific ways to reduce the harmful effects of stress on flight crews, and identified aspects requiring further research. Even thought this study focused on flight crews, the findings apply to the effects of stress on the skilled performance of experts in almost any domain
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