2,297 research outputs found
The Data Processing Pipeline for the Herschel-HIFI Instrument
The HIFI data processing pipeline was developed to systematically process
diagnostic, calibration and astronomical observations taken with the HIFI
science instrumentas part of the Herschel mission. The HIFI pipeline processed
data from all HIFI observing modes within the Herschel automated processing
environment, as well as, within an interactive environment. A common software
framework was developed to best support the use cases required by the
instrument teams and by the general astronomers. The HIFI pipeline was built on
top of that and was designed with a high degree of modularity. This modular
design provided the necessary flexibility and extensibility to deal with the
complexity of batch-processing eighteen different observing modes, to support
the astronomers in the interactive analysis and to cope with adjustments
necessary to improve the pipeline and the quality of the end-products. This
approach to the software development and data processing effort was arrived at
by coalescing the lessons learned from similar research based projects with the
understanding that a degree of foresight was required given the overall length
of the project. In this article, both the successes and challenges of the HIFI
software development process are presented. To support future similar projects
and retain experience gained lessons learned are extracted.Comment: 18 pages, 5 figure
First measurement of gravitational lensing by cosmic voids in SDSS
We report the first measurement of the diminutive lensing signal arising from
matter underdensities associated with cosmic voids. While undetectable
individually, by stacking the weak gravitational shear estimates around 901
voids detected in SDSS DR7 by Sutter et al. (2012a), we find substantial
evidence for a depression of the lensing signal compared to the cosmic mean.
This depression is most pronounced at the void radius, in agreement with
analytical models of void matter profiles. Even with the largest void sample
and imaging survey available today, we cannot put useful constraints on the
radial dark-matter void profile. We invite independent investigations of our
findings by releasing data and analysis code to the public at
https://github.com/pmelchior/void-lensingComment: 6 pages, 5 figures, as accepted by MNRA
Molecular interpretation of pharmaceuticals' adsorption on carbon nanomaterials: Theory meets experiments
The ability of carbon-based nanomaterials (CNM) to interact with a variety of pharmaceutical drugs can be exploited in many applications. In particular, they have been studied both as carriers for in vivo drug delivery and as sorbents for the treatment of water polluted by pharmaceuticals. In recent years, the large number of experimental studies was also assisted by computational work as a tool to provide understanding at molecular level of structural and thermodynamic aspects of adsorption processes. Quantum mechanical methods, especially based on density functional theory (DFT) and classical molecular dynamics (MD) simulations were mainly applied to study adsorption/release of various drugs. This review aims to compare results obtained by theory and experiments, focusing on the adsorption of three classes of compounds: (i) simple organic model molecules; (ii) antimicrobials; (iii) cytostatics. Generally, a good agreement between experimental data (e.g. energies of adsorption, spectroscopic properties, adsorption isotherms, type of interactions, emerged from this review) and theoretical results can be reached, provided that a selection of the correct level of theory is performed. Computational studies are shown to be a valuable tool for investigating such systems and ultimately provide useful insights to guide CNMs materials development and design
Recommended from our members
Weight loss surgery in adolescents corrects high-density lipoprotein subspecies and their function.
Background/objectiveYouth with obesity have an altered high-density lipoprotein (HDL) subspecies profile characterized by depletion of large apoE-rich HDL particles and an enrichment of small HDL particles. The goal of this study was to test the hypothesis that this atherogenic HDL profile is reversible and that HDL function would improve with metabolic surgery.MethodsSerum samples from adolescent males with severe obesity mean±s.d. age of 17.4±1.6 years were studied at baseline and 1 year following vertical sleeve gastrectomy (VSG). HDL subspecies and HDL function were evaluated pre and post VSG using paired t-tests. A lean group of adolescents was included as a reference group.ResultsAfter VSG, body mass index decreased by 32% and insulin resistance as estimated by homeostatic model assessment of insulin resistance decreased by 75% (both P<0.01). Large apoE-rich HDL subspecies increased following VSG (P<0.01) and approached that of lean adolescents despite participants with considerable residual obesity. In addition, HDL function improved compared with baseline (cholesterol efflux capacity increased by 12%, HDL lipid peroxidation potential decreased by 30% and HDL anti-oxidative capacity improved by 25%, all P<0.01).ConclusionsMetabolic surgery results in a significant improvement in the quantity of large HDL subspecies and HDL function. Our data suggest metabolic surgery may improve cardiovascular risk in adolescents and young adults
Cuprate addition to a 6-substituted pentafulvene: preparation of sec-alkyl substituted titanocene dichlorides and their biological activity
The copper-catalysed (10 mol-% CuBr·SMe2, CuCN·LiCl or CuI/PPh3) addition of RMgBr to the pentafulvene 1-(cyclopenta-2,4-dien-1-ylidenemethyl)-2-methoxybenzene allows the formation of cyclopentadienyl derivatives with α-CHR(2-MeOPh) sidechains (R = Me, Et, nBu, iBu, allyl, Ph) without Hâ transfer. The deprotonation of these sec-alkyl-substituted cyclopentadienyls followed by the addition of TiCl4 allows the isolation of TiCl2{η5-C5H4CHR(2-OMePh)} as rac/meso mixtures that show activity against human colon, breast and pancreatic cell lines (GI50 2.3â42.4 ÎŒM)
Theory of pixel lensing towards M31 I: the density contribution and mass of MACHOs
POINT-AGAPE is an Anglo-French collaboration which is employing the Isaac
Newton Telescope (INT) to conduct a pixel-lensing survey towards M31. In this
paper we investigate what we can learn from pixel-lensing observables about the
MACHO mass and fractional contribution in M31 and the Galaxy for the case of
spherically-symmetric near-isothermal haloes. We employ detailed pixel-lensing
simulations which include many of the factors which affect the observables. For
a maximum MACHO halo we predict an event rate in V of up to 100 per season for
M31 and 40 per season for the Galaxy. However, the Einstein radius crossing
time is generally not measurable and the observed full-width half-maximum
duration provides only a weak tracer of lens mass. Nonetheless, we find that
the near-far asymmetry in the spatial distribution of M31 MACHOs provides
significant information on their mass and density contribution. We present a
likelihood estimator for measuring the fractional contribution and mass of both
M31 and Galaxy MACHOs which permits an unbiased determination to be made of
MACHO parameters, even from data-sets strongly contaminated by variable stars.
If M31 does not have a significant population of MACHOs in the mass range
0.001-1 Solar masses strong limits will result from the first season of INT
observations. Simulations based on currently favoured density and mass values
indicate that, after three seasons, the M31 MACHO parameters should be
constrained to within a factor four uncertainty in halo fraction and an order
of magnitude uncertainty in mass (90% confidence). Interesting constraints on
Galaxy MACHOs may also be possible. For a campaign lasting ten years,
comparable to the lifetime of current LMC surveys, reliable estimates of MACHO
parameters in both galaxies should be possible. (Abridged)Comment: 21 pages, 14 figures. Submitted to MNRA
Effective Product Placement
Mit der zunehmenden Verbreitung gezielter Produktplatzierungen in amerikanischen
Unterhaltungsprogrammen wÀchst auch das Interesse der deutschen Werbeindustrie an einer Nutzung dieses Instruments zur werblichen Kommunikation. Bis dato mangelt es jedoch an wissenschaftlichen Untersuchungen, welche die in der Marketingpraxis bestehenden Unsicherheiten hinsichtlich eines effektiven Einsatzes
von Product Placements beseitigen. In der Forschungsliteratur existiert bislang noch
keine umfassende wissenschaftliche Betrachtung potentieller Determinanten und Konsequenzen der Werbewirkung von Product Placements. Das Erkenntnisziel dieser Studie liegt darin, einen wesentlichen Beitrag zur SchlieĂung dieser
ForschungslĂŒcke beizusteuern.
ZunĂ€chst erfolgt eine ausfĂŒhrliche Darstellung des Forschungsstands zur WerbeeffektivitĂ€t von Product Placements. Auf dieser Basis werden die
Determinanten der Einstellungswirkung zur platzierten Marke und der damit verbundenen Kaufabsicht identifiziert. Die erarbeiteten WirkungszusammenhÀnge werden in ein komplexes Hypothesensystem integriert und anhand der Analyse von empirisch erhobenen Daten (n= 309) unter Verwendung eines linearen
Strukturgleichungsmodells ĂŒberprĂŒft.
Die Ergebnisse der Untersuchung belegen, dass die Einstellung zur platzierten Marke und die daraus resultierende Kaufabsicht in hohem MaĂe durch die Gestaltung der Produktplatzierung beeinflusst werden. Darunter erweisen sich
mehrere vom Marketing-Management direkt beeinflussbare Gestaltungsdeterminanten
der WerbeeffektivitĂ€t als signifikant. Die Werbewirkung ist umso effektiver, je höher die wahrgenommene Kongruenz zwischen Marke und Film sowie zwischen Marke und Hauptfigur ausfĂ€llt. Weiterhin ĂŒbt die wahrgenommene AttraktivitĂ€t der Hauptfigur einen positiven Effekt auf die Einstellung zur platzierten Marke aus. SchlieĂlich kann auch ein positiver Einfluss der durch den Film induzierten Stimmung auf die WerbeeffektivitĂ€t von Product Placements
nachgewiesen werden
Resistenz gegenĂŒber Online-Werbung - Einflussfaktoren und Konsequenzen der Werberesistenz im Internet
Die weltweit wachsende Akzeptanz des Mediums Internet fĂŒhrt zu einem steigenden Interesse
der Werbeindustrie an der Nutzung des Mediums zur werblichen Kommunikation. Parallel
wird in der sich verschÀrfenden wissenschaftlichen und öffentlichen Diskussion deutlich, dass
beim Rezipienten erhebliche WiderstÀnde gegen Werbung im Internet auftreten. In der
Konsumentenverhaltensforschung mangelt es jedoch an wissenschaftlichen Untersuchungen,
die sich mit der Thematik Werberesistenz detailliert auseinandersetzen.
Die vorliegende Arbeit befasst sich daher zunÀchst mit der konzeptuellen Erarbeitung des
Konstrukts Werberesistenz durch eine umfangreiche Analyse bisheriger KonzeptualisierungsansÀtze.
Die Auswertung impliziert ein ResistenzverstÀndnis, das sich durch die Kombination
einer Einstellungs- und einer Verhaltenskomponente auszeichnet.
In einem komplexen Hypothesensystem werden anschlieĂend persönlichkeitsbezogene sowie
vom Management beeinflussbare Determinanten der Werberesistenz modelliert. Die
empirische PrĂŒfung des Hypothesensystems erfolgt mittels der LISREL-Kausalanalyse
(n=316). Die Ergebnisse der Studie bestÀtigen die Konzeptualisierung des Konstrukts
Werberesistenz. Im hergeleiteten Bezugsrahmen kann die Relevanz der allgemeinen
Werbeeinstellung, der persönlichkeitsbezogenen Merkmale Extraversion und Neurotizismus
sowie die wahrgenommene Freiheitseinengung durch zu hÀufige Werbekontakte als
Determinanten der Werberesistenz identifiziert werden. AbschlieĂend werden konkrete
MaĂnahmen erlĂ€utert, wie das Marketingmanagement Resistenzen gegenĂŒber OnlineWerbung
unterbinden kann
- âŠ