347 research outputs found
A COMPLETE CHARACTERIZATION OF THE LINEAR, LOG-LINEAR, AND SEMI-LOG INCOMPLETE DEMAND SYSTEM MODELS
This study extends LaFranceÂ’'s (1985, 1986, 1990) previous research by deriving the necessary parameter restrictions for two additional classes of incomplete demand system models to be integrable. In contrast to LaFrance'Â’s earlier work, this analysis considers models that treat expenditures and expenditure shares as the dependent variables in the specified incomplete demand systems. With environmental economists increasingly turning to demand system approaches to value changes in environmental quality, these new results significantly expand the menu of empirical specifications which can be used to fit a given data set. Moreover, the alternative specifications considered in this study, in combination with LaFrance'Â’s original work, represent a complete characterization of the linear, log-linear, and semi-log incomplete demand system models.Research Methods/ Statistical Methods,
Incomplete Demand Systems, Corner Solutions, and Welfare Measurement
This paper demonstrates how corner solutions raise difficulties for the specification, estimation, and use of incomplete demand systems for welfare measurement with disaggregate consumption data, as is common in the outdoor recreation literature. A simple analytical model of consumer behavior is used to elucidate the potential biases for welfare measurement arising from modeling the demand for M goods as a function of M + N prices (N > 1) and income when individuals do not consume all goods in strictly positive quantities. Results from a Monte Carlo experiment suggest that these biases can be substantial for large-scale policy shocks when prices are highly correlated.demand systems, welfare analysis, corner solutions, microeconometrics, Environmental Economics and Policy,
Distributional and Efficiency Impacts of Gasoline Taxes: An Econometrically Based Multi-market Study.
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Distributional and efficiency impacts of gasoline taxes.
This article examines the gasoline tax option being proposed in the U.S. in 2005, employing an econometrically based multi-market simulation model to explore the policy's efficiency and distributional implications. Because of its potential to improve the environment and enhance national security, reducing automobile-related gasoline consumption has become a major U.S. public policy issue. Policy impacts both in the aggregate and across households distinguished by income, car-ownership, and other characteristics were examined. Simulation results show that whether a gas-tax increase is regressive in its impact depends on the manner in which the tax revenues are recycled to the economy. The results also reveal significant heterogeneity in welfare impacts within household income groups, thus highlighting the importance of accounting for household heterogeneity in tastes and car-ownership in evaluating distributional impacts.
How Do Gasoline Prices Affect Fleet Fuel Economy?
Exploiting a rich data set of passenger vehicle registrations in twenty U.S. metropolitan statistical areas from 1997 to 2005, we examine the effects of gasoline prices on the automotive fleet's composition. We find that high gasoline prices affect fleet fuel economy through two channels: (1) shifting new auto purchases towards more fuel-efficient vehicles, and (2) speeding the scrappage of older, less fuel-efficient used vehicles. Policy simulations based on our econometric estimates suggest that a 10% increase in gasoline prices from 2005 levels will generate a 0.22% increase in fleet fuel economy in the short run and a 2.04% increase in the long run.
Dexmedetomidine Prevents Lipopolysaccharide-Induced MicroRNA Expression in the Adult Rat Brain
During surgery or infection, peripheral inflammation can lead to
neuroinflammation, which is associated with cognitive impairment,
neurodegeneration, and several neurodegenerative diseases. Dexmedetomidine, an
α-2-adrenoceptor agonist, is known to exert anti-inflammatory and
neuroprotective properties and reduces the incidence of postoperative
cognitive impairments. However, on the whole the molecular mechanisms are
poorly understood. This study aims to explore whether dexmedetomidine
influences microRNAs (miRNAs) in a rat model of lipopolysaccharide
(LPS)-induced neuroinflammation. Adult Wistar rats were injected with 1 mg/kg
LPS intraperitoneal (i.p.) in the presence or absence of 5 µg/kg
dexmedetomidine. After 6 h, 24 h, and 7 days, gene expressions of interleukin
1-β (IL1-β), tumor necrosis factor-α (TNF-α), and microRNA expressions of miR
124, 132, 134, and 155 were measured in the hippocampus, cortex, and plasma.
Dexmedetomidine decreased the LPS-induced neuroinflammation in the hippocampus
and cortex via significant reduction of the IL1-β and TNF-α gene expressions
after 24 h. Moreover, the LPS-mediated increased expressions of miR 124, 132,
134, and 155 were significantly decreased after dexmedetomidine treatment in
both brain regions. In plasma, dexmedetomidine significantly reduced LPS-
induced miR 155 after 6 h. Furthermore, there is evidence that miR 132 and 134
may be suitable as potential biomarkers for the detection of
neuroinflammation. View Full-Tex
Distributional and efficiency impacts of gasoline taxes
This article examines the gasoline tax option being proposed in the U.S. in 2005, employing an econometrically based multi-market simulation model to explore the policy's efficiency and distributional implications. Because of its potential to improve the environment and enhance national security, reducing automobile-related gasoline consumption has become a major U.S. public policy issue. Policy impacts both in the aggregate and across households distinguished by income, car-ownership, and other characteristics were examined. Simulation results show that whether a gas-tax increase is regressive in its impact depends on the manner in which the tax revenues are recycled to the economy. The results also reveal significant heterogeneity in welfare impacts within household income groups, thus highlighting the importance of accounting for household heterogeneity in tastes and car-ownership in evaluating distributional impacts
In vivo application of Granulocyte-Macrophage Colony-stimulating Factor enhances postoperative qualitative monocytic function
BACKGROUND: Granulocyte macrophage colony-stimulating factor (GM-CSF) can be
used as a potent stimulator for immune suppressed patients as defined by a
decrease of human leukocyte antigen-D related expression on monocytes (mHLA-
DR) after surgery. However, the exact role of GM-CSF on monocytic and T cell
function is unclear. METHODS: In this retrospective randomized controlled
trial (RCT) subgroup analysis, monocytic respectively T cell function and T
cell subspecies of 20 immune suppressed (i.e. mHLA-DR levels below 10,000
monoclonal antibodies (mAb) per cell at the first day after surgery) patients
after esophageal or pancreatic resection were analyzed. Each 10 patients
received either GM-CSF (250 μg/m²/d) or placebo for a maximum of three
consecutive days if mHLA-DR levels remained below 10,000 mAb per cell. mHLA-DR
and further parameters of immune function were measured preoperatively (od)
until day 5 after surgery (pod5). Statistical analyses were performed using
nonparametric statistical procedures. RESULTS: In multivariate analysis, mHLA-
DR significantly differed between the groups (p < 0.001). mHLA-DR was
increased on pod2 (p < 0.001) and pod3 (p = 0.002) after GM-CSF application.
Tumor necrosis factor-α (TNF-α) release of lipopolysaccharide (LPS) stimulated
monocytes multivariately significantly differed between the groups (p < 0.008)
and was increased in the GM-CSF group on pod2 (p < 0.001) and pod3 (p =
0.046). Th17/regulatory T (Treg) cell ratio was higher after GM-CSF treatment
on pod2 (p = 0.041). No differences were seen in lymphocytes and T helper cell
(Th)1/Th2 specific cytokine production after T cell stimulation with
Concanavalin (Con) A between the groups. CONCLUSIONS: Postoperative
application of GM-CSF significantly enhanced qualitative monocytic function by
increased mHLA-DR and TNF-α release after LPS stimulation and apparently
enhanced Th17/Treg ratio
Smoking, Gender, and Overweight Are Important Influencing Factors on Monocytic HLA-DR before and after Major Cancer Surgery
Background. Monocytic human leukocyte antigen D related (mHLA-DR) is essential
for antigen-presentation. Downregulation of mHLA-DR emerged as a general
biomarker of impaired immunity seen in patients with sepsis and pneumonia and
after major surgery. Influencing factors of mHLA-DR such as age, overweight,
diabetes, smoking, and gender remain unclear. Methods. We analyzed 20 patients
after esophageal or pancreatic resection of a prospective, randomized,
placebo-controlled, double-blind trial (placebo group). mHLA-DR was determined
from day of surgery (od) until postoperative day (pod) 5. Statistical analyses
were performed using multivariate generalized estimating equation analyses
(GEE), nonparametric multivariate analysis of longitudinal data, and
univariate post hoc nonparametric Mann–Whitney tests. Results. In GEE, smoking
and gender were confirmed as significant influencing factors over time.
Univariate analyses of mHLA-DR between smokers and nonsmokers showed lower
preoperative levels () and a trend towards lower levels on pod5 () in smokers.
Lower mHLA-DR was seen in men on pod3 () and on pod5 (). Overweight patients
(BMI > 25 kg/m2) had lower levels of mHLA-DR on pod3 () and pod4 ().
Conclusion. Smoking is an important influencing factor on pre- and
postoperative immune function while postoperative immune function was
influenced by gender and overweight. Clinical trial registered with
ISRCTN27114642
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