1,902 research outputs found
Heterogeneous Response Functions in Advertising
De Fleur (1956) provides the earliest evidence of diminishing returns. He finds a common logarithmic pattern for leaflets dropped and message recalled in field experiment. Since then, many researchers have applied logarithmic or square root patterns to capture the effect of diminishing returns with their advertising response modeling across different media. But discussions with managers support the notion that the diminishing returns to incremental dollars spent on one medium (say, television) are not likely to be the same as those for equivalent dollars spent on other media (e.g., Print). But if diminishing returns indeed vary across media, how does that change the resulting allocation recommendation? To address this issue, we derive a dynamic model that captures the notion of differential diminishing returns and disentangles it from closely related notions of differential carryovers and differential ad effectiveness. Second, we develop a systematic method to estimate the model's parameters using market data and illustrate empirically that all three effects, diminishing returns, carryover and ad effectiveness vary across the four media employed. Finally, we investigate the normative implications for managerial decision-making. Here, we additionally account for varying media buying efficiencies across media. Taken together, the approach and its illustration should provide managers with a better toolkit to allocate their multimedia budgets. --
Markov-Switching Model Selection Using Kullback-Leibler Divergence
In Markov-switching regression models, we use Kullback-Leibler (KL) divergence between the true and candidate models to select the number of states and variables simultaneously. In applying Akaike information criterion (AIC), which is an estimate of KL divergence, we find that AIC retains too many states and variables in the model. Hence, we derive a new information criterion, Markov switching criterion (MSC), which yields a marked improvement in state determination and variable selection because it imposes an appropriate penalty to mitigate the over-retention of states in the Markov chain. MSC performs well in Monte Carlo studies with single and multiple states, small and large samples, and low and high noise. Furthermore, it not only applies to Markov-switching regression models, but also performs well in Markov- switching autoregression models. Finally, the usefulness of MSC is illustrated via applications to the U.S. business cycle and the effectiveness of media advertising.Research Methods/ Statistical Methods,
Denoised least squares estimators: An application to estimating advertising effectiveness
This is the publisher's version, also available electronically from http://www3.stat.sinica.edu.tw/statistica/j10n4/j10n412/j10n412.htm.It is known in marketing science that an advertiser under- or overspends millions of dollars on advertising because the estimation of advertising effectiveness is biased. This bias is induced by measurement noise in advertising variables, such as awareness and television rating points, which are provided by commercial market research firms based on small-sample surveys of consumers. In this paper, we propose a denoised regression approach to deal with the problem of noisy variables. We show that denoised least squares estimators are consistent. Simulation results indicate that the denoised regression approach outperforms the classical regression approach. A marketing example is presented to illustrate the use of denoised least squares estimators
Bovine rotavirus pentavalent vaccine development in India
AbstractA bovine rotavirus pentavalent vaccine (BRV-PV) containing rotavirus human-bovine (UK) reassortant strains of serotype G1, G2, G3, G4 and G9 has been developed by the Serum Institute of India Ltd, in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID), USA. The vaccine underwent animal toxicity studies and Phase I and II studies in adults, toddlers and infants. It has been found safe and immunogenic and will undergo a large Phase III study to assess efficacy against severe rotavirus gastroenteritis
Oxidative and pro-inflammatory impact of regular and denicotinized cigarettes on blood brain barrier endothelial cells: is smoking reduced or nicotine-free products really safe?
Background: Both active and passive tobacco smoke (TS) potentially impair the vascular endothelial function in a causative and dose-dependent manner, largely related to the content of reactive oxygen species (ROS), nicotine, and pro-inflammatory activity. Together these factors can compromise the restrictive properties of the blood–brain barrier (BBB) and trigger the pathogenesis/progression of several neurological disorders including silent cerebral infarction, stroke, multiple sclerosis and Alzheimer’s disease. Based on these premises, we analyzed and assessed the toxic impact of smoke extract from a range of tobacco products (with varying levels of nicotine) on brain microvascular endothelial cell line (hCMEC/D3), a well characterized human BBB model.
Results: Initial profiling of TS showed a significant release of reactive oxygen (ROS) and reactive nitrogen species (RNS) in full flavor, nicotine-free (NF, “reduced-exposure” brand) and ultralow nicotine products. This release correlated with increased oxidative cell damage. In parallel, membrane expression of endothelial tight junction proteins ZO-1 and occludin were significantly down-regulated suggesting the impairment of barrier function. Expression of VE-cadherin and claudin-5 were also increased by the ultralow or nicotine free tobacco smoke extract. TS extract from these cigarettes also induced an inflammatory response in BBB ECs as demonstrated by increased IL-6 and MMP-2 levels and up-regulation of vascular adhesion molecules, such as VCAM-1 and PECAM-1.
Conclusions: In summary, our results indicate that NF and ultralow nicotine cigarettes are potentially more
harmful to the BBB endothelium than regular tobacco products. In addition, this study demonstrates that the
TS-induced toxicity at BBB ECs is strongly correlated to the TAR and NO levels in the cigarettes rather than the
nicotine conten
1-Acryloyl-2,6-bis(4-chlorophenyl)-3,5-dimethylpiperidin-4-one
In the crystal structure of the title compound, C22H21Cl2NO2, the piperidinone ring is in a boat conformation
Institutional learning and change: a review of concepts and principles Policy Brief 21
To improve the performance of agricultural research, many
international and national research organisations have embarked
on impact assessment exercises. These exercises have estimated
technology adoption and economic rates of return to research
investments. Such exercises in ICAR have contributed to
accountability, and provided evidence on whether public funds
have been spent judiciously. However, for evaluation to be
effective, it must encompass both accountability and learning
objectives. It appears that less emphasis has been given to the
latter. Hall et al (2003a) state that impact assessment efforts
(in international research arenas) have not yielded desired results
because of the weak diagnostic power of commonly used impact
assessment techniques. These techniques fail to recognise
research as a complex process of interactions shaped by the habits
and practices of those involved which are critical for improving
research performance
Global gene expression analysis of pigeonpea with male sterility conditioned by A 2 cytoplasm
Cytoplasmic male sterility(CMS), a maternally inherited trait, provides a promising means to harness yield gains associated with hybrid vigor. In pigeonpea [Cajanus cajan (L.) Huth], nine types of sterility-inducing cytoplasm have been reported, of which A2 and A4 have been successfully deployed in hybrid breeding. Unfortunately, molecular mechanism of the CMS trait is poorly understood because of limited research invested. More recently, an association between a mitochondrial gene (nad7) and A4-CMS has been demonstrated in pigeonpea; however, the mechanism underlying A2-CMS still remains obscure. The current investigation aimed to analyze the differences in A2-CMS line (ICPL 88039A) and its isogenic maintainer line (ICPL 88039B) at transcriptome level using next-generation sequencing. Gene expression profiling uncovered a set of 505 genes that showed altered expression in response to CMS, of which, 412 genes were upregulated while 93 were downregulated in the fertile maintainer line vs. the CMS line. Further, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analyses revealed association of CMS in pigeonpea with four major pathways: glucose and lipid metabolism, ATP production, pollen development and pollen tube growth, and reactive oxygen species (ROS) scavenging. Patterns of digital gene expression were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) of six candidate genes. This study elucidates candidate genes and metabolic pathways having potential associations with pollen development and male sterility in pigeonpea A2-CMS. New insights on molecular mechanism of CMS trait in pigeonpea will be helpful to accelerate heterosis utilization for enhancing productivity gains in pigeonpea
Choice Models and Customer Relationship Management
Customer relationship management (CRM) typically involves tracking individual customer behavior over time, and using this knowledge to configure solutions precisely tailored to the customers' and vendors' needs. In the context of choice, this implies designing longitudinal models of choice over the breadth of the firm's products and using them prescriptively to increase the revenues from customers over their lifecycle. Several factors have recently contributed to the rise in the use of CRM in the marketplacePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47023/1/11002_2005_Article_5892.pd
MENCA experiment aboard India’s Mars Orbiter Mission
The Mars Exospheric Neutral Composition Analyser (MENCA) aboard the Indian Mars Orbiter Mission (MOM) is a quadrupole mass spectrometer-based experiment. Making use of the highly elliptical and low inclination (~150°) orbit of MOM, MENCA will conduct in situ measurements of the composition and radial distribution of the Martian neutral exosphere in the 1–300 amu mass range in the equatorial and low latitudes of Mars. The functionality of MENCA has been tested during the Earth-bound and heliocentric phases of MOM before its operation in the Martian orbit. This article describes the scientific objectives, instrument details, design and development, test and evaluation, and calibration of the MENCA instrument
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