264 research outputs found
Investigating international new product diffusion speed: A semiparametric approach
Global marketing managers are interested in understanding the speed of the
new product diffusion process and how the speed has changed in our ever more
technologically advanced and global marketplace. Understanding the process
allows firms to forecast the expected rate of return on their new products and
develop effective marketing strategies. The most recent major study on this
topic [Marketing Science 21 (2002) 97--114] investigated new product diffusions
in the United States. We expand upon that study in three important ways. (1)
Van den Bulte notes that a similar study is needed in the international
context, especially in developing countries. Our study covers four new product
diffusions across 31 developed and developing nations from 1980--2004. Our
sample accounts for about 80% of the global economic output and 60% of the
global population, allowing us to examine more general phenomena. (2) His model
contains the implicit assumption that the diffusion speed parameter is constant
throughout the diffusion life cycle of a product. Recognizing the likely
effects on the speed parameter of recent changes in the marketplace, we model
the parameter as a semiparametric function, allowing it the flexibility to
change over time. (3) We perform a variable selection to determine that the
number of internet users and the consumer price index are strongly associated
with the speed of diffusion.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS519 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Unidentified EGRET Sources and the Extragalactic Gamma-Ray Background
The large majority of EGRET point sources remain to this day without an
identified low-energy counterpart. Whatever the nature of the EGRET
unidentified sources, faint unresolved objects of the same class must have a
contribution to the diffuse gamma-ray background: if most unidentified objects
are extragalactic, faint unresolved sources of the same class contribute to the
background, as a distinct extragalactic population; on the other hand, if most
unidentified sources are Galactic, their counterparts in external galaxies will
contribute to the unresolved emission from these systems. Understanding this
component of the gamma-ray background, along with other guaranteed
contributions from known sources, is essential in any attempt to use gamma-ray
observations to constrain exotic high-energy physics. Here, we follow an
empirical approach to estimate whether a potential contribution of unidentified
sources to the extragalactic gamma-ray background is likely to be important,
and we find that it is. Additionally, we comment on how the anticipated GLAST
measurement of the diffuse gamma-ray background will change, depending on the
nature of the majority of these sources.Comment: 6 pages, 3 figures, to appear in proceedings of "The Multi-Messenger
Approach to High Energy Gamma-Ray Sources", Barcelona, 4-7 July 2006;
comments welcom
HATS-18 b: An Extreme Short--Period Massive Transiting Planet Spinning Up Its Star
We report the discovery by the HATSouth network of HATS-18 b: a 1.980 +/-
0.077 Mj, 1.337 +0.102 -0.049 Rj planet in a 0.8378 day orbit, around a solar
analog star (mass 1.037 +/- 0.047 Msun, and radius 1.020 +0.057 -0.031 Rsun)
with V=14.067 +/- 0.040 mag. The high planet mass, combined with its short
orbital period, implies strong tidal coupling between the planetary orbit and
the star. In fact, given its inferred age, HATS-18 shows evidence of
significant tidal spin up, which together with WASP-19 (a very similar system)
allows us to constrain the tidal quality factor for Sun-like stars to be in the
range 6.5 <= lg(Q*/k_2) <= 7 even after allowing for extremely pessimistic
model uncertainties. In addition, the HATS-18 system is among the best systems
(and often the best system) for testing a multitude of star--planet
interactions, be they gravitational, magnetic or radiative, as well as planet
formation and migration theories.Comment: Submitted. 12 pages, 9 figures, 5 table
Prospectus, December 7, 1976
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HATS-1b: The first transiting planet discovered by the hatsouth survey
We report the discovery of HATS-1b, a transiting extrasolar planet orbiting the moderately bright V = 12.05 G dwarf star GSC 6652-00186, and the first planet discovered by HATSouth, a global network of autonomous wide-field telescopes. HATS-1b has a period of P ≈ 3.4465 days, mass of Mp ≈ 1.86 MJ, and radius of Rp ≈ 1.30 RJ. The host star has a mass of 0.99 M⊙ and radius of 1.04 R⊙. The discovery light curve of HATS-1b has near-continuous coverage over several multi-day timespans, demonstrating the power of using a global network of telescopes to discover transiting planets.Development of the HATSouth project was funded by NSF
MRI grant NSF/AST-0723074, operations are supported by
NASA grant NNX09AB29G, and follow-up observations received
partial support from grant NSF/AST-1108686. Followup
observations with the ESO 2.2 m/FEROS instrument were performed under MPI guaranteed time (P087.A-9014(A),
P088.A-9008(A), P089.A-9008(A)) and Chilean time (P087.C-
0508(A)). A.J. acknowledges support from Fondecyt project
1095213, Ministry of Economy ICM Nuclei P07-021-F and
P10-022-F, Anillo ACT-086 and BASAL CATA PFB-06. V.S.
acknowledges support form BASAL CATA PFB-06. M.R. acknowledges
support from a Fondencyt postdoctoral fellowship
N 3120097 and contributions from the ALMA-CONICYT
FUND Project N 31090015. R.B. and N.E. acknowledge support
from Fondecyt project 1095213. Work at the
Australian National University is supported by ARC Laureate
Fellowship Grant FL0992131. We acknowledge the use of
the AAVSO Photometric All-Sky Survey (APASS), funded by
the Robert Martin Ayers Sciences Fund, and the SIMBAD
database, operated at CDS, Strasbourg, France
HATS-5b: A transiting hot saturn from the HATsouth survey
We report the discovery of HATS-5b, a transiting hot Saturn orbiting a G-type star, by the HATSouth survey. HATS-5b has a mass of Mp 0.24 MJ, radius of Rp 0.91 R J, and transits its host star with a period of P 4.7634 days. The radius of HATS-5b is consistent with both theoretical and empirical models. The host star has a V-band magnitude of 12.6, mass of 0.94 M ⊙, and radius of 0.87 R. The relatively high scale height of HATS-5b and the bright, photometrically quiet host star make this planet a favorable target for future transmission spectroscopy follow-up observations. We reexamine the correlations in radius, equilibrium temperature, and metallicity of the close-in gas giants and find hot Jupiter-mass planets to exhibit the strongest dependence between radius and equilibrium temperature. We find no significant dependence in radius and metallicity for the close-in gas giant population.Development of the HATSouth project was funded by NSF
MRI grant NSF/AST-0723074, operations are supported by
NASA grant NNX12AH91H, and follow-up observations receive
partial support from grant NSF/AST-1108686. Work at
the Australian National University is supported by ARC Laureate
Fellowship Grant FL0992131. A.J.
acknowledges support from FONDECYT project 1130857,
BASAL CATA PFB-06, and projects IC120009 “Millennium
Institute of Astrophysics (MAS)” and P10-022-F of the Millennium
Science Initiative, Chilean Ministry of Economy. V.S.
acknowledges support form BASAL CATA PFB-06. M.R. acknowledges
support from FONDECYT postdoctoral fellowship
No3120097. R.B. and N.E. acknowledge support from
CONICYT-PCHA/Doctorado Nacional and Fondecyt project
1130857. We acknowledge the
use of the AAVSO Photometric All-Sky Survey (APASS),
funded by the Robert Martin Ayers Sciences Fund, and the
SIMBAD database, operated at CDS, Strasbourg, France. Operations
at the MPG/ESO 2.2 m telescope are jointly performed
by the Max Planck Gesellschaft and the European Southern
Observatory. Australian access to the Magellan Telescopes was supported
through the National Collaborative Research Infrastructure
Strategy of the Australian Federal Government
Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111
We present the results of extensive multi-frequency monitoring of the radio
galaxy 3C 111 between 2004 and 2010 at X-ray (2.4--10 keV), optical (R band),
and radio (14.5, 37, and 230 GHz) wave bands, as well as multi-epoch imaging
with the Very Long Baseline Array (VLBA) at 43 GHz. Over the six years of
observation, significant dips in the X-ray light curve are followed by
ejections of bright superluminal knots in the VLBA images. This shows a clear
connection between the radiative state near the black hole, where the X-rays
are produced, and events in the jet. The X-ray continuum flux and Fe line
intensity are strongly correlated, with a time lag shorter than 90 days and
consistent with zero. This implies that the Fe line is generated within 90
light-days of the source of the X-ray continuum. The power spectral density
function of X-ray variations contains a break, with steeper slope at shorter
timescales. The break timescale of 13 (+12,-6) days is commensurate with
scaling according to the mass of the central black hole based on observations
of Seyfert galaxies and black hole X-ray binaries (BHXRBs). The data are
consistent with the standard paradigm, in which the X-rays are predominantly
produced by inverse Compton scattering of thermal optical/UV seed photons from
the accretion disk by a distribution of hot electrons --- the corona ---
situated near the disk. Most of the optical emission is generated in the
accretion disk due to reprocessing of the X-ray emission. The relationships
that we have uncovered between the accretion disk and the jet in 3C 111, as
well as in the FR I radio galaxy 3C 120 in a previous paper, support the
paradigm that active galactic nuclei and Galactic BHXRBs are fundamentally
similar, with characteristic time and size scales proportional to the mass of
the central black holeComment: Accepted for publication in ApJ. 18 pages, 17 figures, 11 tables
(full machine readable data-tables online in ApJ website
Enduring science: Three decades of observing the Northeast Atlantic from the Porcupine Abyssal Plain Sustained Observatory (PAP-SO)
Until the 1980s, the deep sea was generally considered to be a particularly stable environment, free from major temporal variations (Sanders, 1968). Studies in the abyssal northeast Atlantic by Billett et al. (1983), and subsequently Lampitt (1985) discovered seasonal pulses of surface primary production-derived particulate organic matter (phytodetritus), and hence carbon, at abyssal depths. These early observations were subsequently extended to the central oceanic region of the NE Atlantic (Pfannkuche, 1993; Thiel et al., 1989), and prompted the establishment of more concerted time series studies in the Porcupine Abyssal Plain area. Today, the Porcupine Abyssal Plain Sustained Observatory (PAP–SO) is a multidisciplinary open-ocean time series site in the NE Atlantic (48°50′N 16°30′W, 4850 m water depth; Fig. 1), focused on the study of connections between the surface and deep ocean. In situ measurements of climatically and environmentally relevant variables have been made for more than 30 years. This represents an exceptionally long time series - a recent compilation of biological time series data, across terrestrial, freshwater, and marine realms, indicates an average duration of only 13-years (Dornelas et al., 2018). Long-term time series in the deep sea are rare, particularly those collecting data from surface to seabed. The PAP-SO is one of two abyssal long-term time series sites globally (Smith et al. 2015), the other being a thirty-year time series at Station M in the northeastern Pacific Ocean (34°50′N, 123°00′W, ~4000 m water depth), maintained by the Monterey Bay Aquarium Research Institute (Smith et al., 2020). This ‘sibling’ abyssal time series site also aims to understand the connections between the surface ocean and the seabed, using many similar techniques (Smith et al., 2017), facilitating comparisons between the two sites (e.g. Durden et al., 2019; Durden et al., 2020a; Laguionie-Marchais et al., 2013; Smith et al., 2009). Another source of extended comparison is the 21 year time series Long-Term Ecological Research Observatory HAUSGARTEN, Frontiers in Arctic Marine Monitoring (FRAM) in the Fram Strait between the North Atlantic and the central Arctic Ocean (78.5°N–80°N, 05°W–11°E, 250–5500 m water depth), maintained by the Alfred Wegener Institute for Polar and Marine Research (Soltwedel et al., 2016; Soltwedel et al., 2005). Much of our understanding of temporal variation in the deep sea, and connections between the surface ocean and the seabed have been derived from research conducted at these observatories
HATS-17b: A TRANSITING COMPACT WARM JUPITER in A 16.3 DAY CIRCULAR ORBIT
We report the discovery of HATS-17b, the first transiting warm Jupiter of the HATSouth network. HATS-17b transits its bright (V = 12.4) G-type ( = , = ) metal-rich ([Fe/H] = +0.3 dex) host star in a circular orbit with a period of P = days. HATS-17b has a very compact radius of given its Jupiter-like mass of . Up to 50% of the mass of HATS-17b may be composed of heavy elements in order to explain its high density with current models of planetary structure. HATS-17b is the longest period transiting planet discovered to date by a ground-based photometric survey, and is one of the brightest transiting warm Jupiter systems known. The brightness of HATS-17 will allow detailed follow-up observations to characterize the orbital geometry of the system and the atmosphere of the planet
Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways
It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers
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