bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Market Experience Eliminate Market Anomalies? The Case of Exogenous Market Experience
Authors: List John A
Published: June 2011

A vibrant literature has emerged that suggests willingness to pay and willingness to accept measures of value are quite different for inexperienced consumers but that value differences erode with market experience. One potential shortcoming of this literature is that market experience is endogenous. This study presents a framed field experiment that exogenously induces market experience. Empirical findings support the premise that market experience, alone, can eliminate an important market anomaly.
Long-Run Mortality Effects of Vietnam-Era Army Service: Evidence from Australia's Conscription Lotteries
Authors: Siminski Peter , Ville Simon
Published: June 2011

We estimate the effect of Vietnam-era Army service on mortality, exploiting Australia's conscription lotteries for identification. We utilize population data on deaths during 1994–2007 and military personnel records. The estimates are identified by over 51,000 compliers induced to enlist in the Army. We find no statistically significant effects on mortality overall, nor for any cause of death. The estimated relative risk (RR) of death associated with Army service is 1.03 (95% CI: 0.92, 1.19). On the assumption that Army service affected mortality only for those who served in Vietnam, the estimated RR is 1.06 (95% CI: 0.81, 1.51).
Race and Home Ownership from the End of the Civil War to the Present
Authors: Collins William J , Margo Robert A
Published: June 2011

We present new estimates of home ownership for black and white households from 1870 to 2007. Black ownership increased by 46 percentage points, whereas white ownership increased by 20 points. Remarkably, 25 of the 26 point narrowing occurred between 1870 and 1910. Part of this early convergence is accounted for by falling white ownership due to movement out of agriculture, but most is accounted for by post-emancipation gains among blacks. After 1910, white and black households increased ownership, but the racial gap barely changed. We discuss the influence of residential segregation, public policy, and permanent income on the ownership gap.
Land and Racial Wealth Inequality
Authors: Miller Melinda C
Published: June 2011

Could racial wealth inequality have been reduced if freed slaves had been granted land following the Civil War? This paper exploits a plausibly exogenous variation in policies of the Cherokee Nation and southern United States to identify the impact of free land on the size of the racial wealth gap. Using data on land, livestock, and home ownership, I find evidence that former slaves who had access to free land were absolutely wealthier and experienced lower levels of racial wealth inequality in 1880 than former slaves who did not. Furthermore, their children continued to experience these advantages in 1900.
Part D Formulary and Benefit Design as a Risk-Steering Mechanism
Authors: Goldman Dana P , Joyce Geoffrey F , Vogt William B
Published: June 2011

Medicare Part D relies upon drug plan competition. Plans have enormous scope to design benefits and to set premiums, but they may not charge differential premiums based on risk. We use the formulary and benefit design of all Medicare prescription drug plans and pharmacy claims data to construct a simulation model of out-of-pocket drug spending. We use this simulation model to examine individual incentives in Medicare Part D for adverse selection. We find that high drug users have much stronger incentives to enroll in generous plans than do low users, thus there is significant scope for adverse selection.
Crash and Wait? The Impact of the Great Recession on the Retirement Plans of Older Americans
Authors: McFall Brooke Helppie
Published: June 2011

This study uses data from pre- and post-crash surveys from the Cognitive Economics study to examine the impact of recent stock and labor market wealth losses on the planned retirement ages of older Americans. Regression estimates imply that the average wealth loss between July 2008 and May/June 2009 is associated with an increase in planned retirement age of approximately 2.5 months. Furthermore, pessimism about future stock market returns is found to amplify the impact of wealth losses on retirement timing.
Market Sentiment: A Tragedy of the Commons
Authors: Hassan Tarek A , Mertens Thomas M
Published: June 2011

We present a model in which investors decide whether or to what degree they want to allow their behavior to be influenced by “market sentiment.” Investors who choose to insulate their decisions from market sentiment earn higher expected returns, but incur a small mental cost. We show that if information is moderately dispersed across investors, even a very small mental cost may result in a significant amount of sentiment in equilibrium: Individuals who choose to be swayed by sentiment increase uncertainty about the future and make it less costly for others to be swayed by sentiment as well.
Leverage and the Financial Accelerator in a Liquidity Trap
Authors: Mertens Karel , Ravn Morten O
Published: June 2011

We show that the financial accelerator may be very large in a liquidity trap. We study a sticky price model with real estate and a financial friction specified as a collateral constraint. Expectations can lead the economy to a self-fulfilling liquidity trap equilibrium where the lower bound on the nominal interest rate binds. We model these equilibria as stochastic sunspots. As in the Great Depression, a liquidity trap entails house price depreciation and potentially large output losses. Higher leverage implies much larger output losses but at the same time rules out the existence of short-lived liquidity traps.
Water Quality Violations and Avoidance Behavior: Evidence from Bottled Water Consumption
Authors: Zivin Joshua Graff , Neidell Matthew , Schlenker Wolfram
Published: June 2011

We examine the impact of poor water quality on avoidance behavior by estimating the change in bottled water purchases in response to drinking water violations. Using data from a national grocery chain matched with water quality violations, we find an increase in bottled water sales of 22 percent from violations due to microorganisms and 17 percent from violations due to elements and chemicals. Back-of-the envelope calculations yield costs of avoidance behavior at roughly $60 million for all nationwide violations in 2005, which likely reflects a significant understatement of the total willingness to pay to eliminate violations.
Labor Supply and the Extensive Margin
Authors: Blundell Richard , Bozio Antoine , Laroque Guy
Published: June 2011

In this paper we propose a systematic way of examining the importance of the extensive and the intensive margins of labor supply in order to explain the overall movements in total hours of work over time. We show how informative bounds can be developed on each of these margins. We apply this analysis to the evolution of hours of work in the US, the UK, and France and show that both the extensive and intensive margins matter in explaining changes in total hours.
A Labor Supply Elasticity Accord?
Authors: Ljungqvist Lars , Sargent Thomas J
Published: June 2011

A dispute about the size of the aggregate labor supply elasticity has been fortified by a contentious aggregation theory used by real business cycle theorists. The replacement of that aggregation theory with one more congenial to microeconomic observations opens possibilities for an accord about the aggregate labor supply elasticity. The new aggregation theory drops features to which empirical microeconomists objected and replaces them with life-cycle choices. Whether the new aggregation theory ultimately indicates a small or large macro labor supply elasticity will depend on how shocks and government institutions interact to put workers at interior solutions for career length.
Which Dimensions of Culture Matter for Long-Run Growth?
Authors: Gorodnichenko Yuriy , Roland Gerard
Published: June 2011

We present empirical evidence that, among a variety of cultural dimensions, the individualism-collectivism dimension, based on Hofstede's (2001) data, is the most important and robustly significant effect of culture on long run growth. Other dimensions that have a significant effect, albeit less robust, are generally strongly correlated with individualism and convey similar information. We found no significant or robust effect on growth from cultural dimensions that are independent from the individualism-collectivism cleavage.
Social Preferences and Fairness Norms as Informal Institutions: Experimental Evidence
Authors: Jakiela Pamela
Published: June 2011

We conduct a series of dictator games in which the status of the dictator relative to other players varies across treatments. Experiments are conducted in a conventional university lab and in villages in rural Kenya. We find that status is an important determinant of dictator game giving, but the relative importance of earned and unearned status differs across cultures.
More Evidence on the Performance of Merger Simulations
Authors: Weinberg Matthew C
Published: June 2011

Merger simulations are commonly used to simulate the effects of potential mergers. Despite the large resources devoted to merger review, little evidence exists on the accuracy of these methods. This paper uses the acquisition of Tambrands by Proctor and Gamble to provide evidence on the efficacy of merger simulation. Two simple demand systems are estimated under several identification assumptions and combined with a static model of price competition. Simulations predict small price effects of about 1 percent for the merging firms' brands, while direct estimates indicate the merger raised prices by 5–8 percent.
Gender Gap in Performance under Competitive Pressure: Admissions to Czech Universities
Authors: Jurajda Štěpán , Münich Daniel
Published: June 2011

Do women perform worse than equally able men in stressful competitive settings? We ask this question for competitions with a high payoff—admissions to tuition-free selective universities. With data on an entire cohort of Czech students graduating from secondary schools and applying to universities, we show that, compared to men of similar general skills and subject-of-study preferences, women perform similarly well when competition is less intense, but perform substantially worse (are less likely to be admitted) when applying to very selective universities.
The Roma/Non-Roma Test Score Gap in Hungary
Authors: Kertesi Gábor , Kézdi Gábor
Published: June 2011

This paper documents and decomposes the test score gap between Roma and non-Roma 8th graders in Hungary in 2006. Our data connect national standardized test scores to an individual panel survey with detailed data on ethnicity and family background. The test score gap is approximately one standard deviation for both reading and mathematics, which is similar to the gap between African-American and White students of the same age group in the US in the 1980s. After accounting for on health, parenting, school fixed effects and family background, the gap disappears in reading and drops to 0.15 standard deviation in mathematics.
Oaxaca-Blinder as a Reweighting Estimator
Authors: Kline Patrick
Published: June 2011

The classic regression based estimator of counterfactual means studied by Ronald Oaxaca (1973) and Alan Blinder (1973) is shown to constitute a propensity score reweighting estimator based upon a linear model for the conditional odds of being treated.
Global Financial Crisis and Africa: Is the Impact Permanent or Transitory? Time Series Evidence from North Africa
Authors: Aly Hassan Y , Strazicich Mark C
Published: June 2011

We utilize time series tests with structural breaks to test for an adverse impact on economic growth rates in North Africa associated with the recent US financial crisis and global recession. One or two breaks are identified for each country, except for Morocco where no break is found, while breaks coincide with the 2008 financial crisis in only two of the six countries (Libya and Mauritania). These findings suggest that, in general, shocks from the recent financial crisis have only temporary effects on economic growth in these countries. Impulse response functions with breaks confirm these results. We conclude by suggesting explanations for these findings.
Estimating the Willingness to Pay to Avoid Violent Crime: A Dynamic Approach
Authors: Bishop Kelly C , Murphy Alvin D
Published: June 2011

The hedonic model, which has been used extensively in the Environmental, Urban, and Real Estate literatures, allows for the estimation of the implicit prices of housing and neighborhood attributes, as well as households' demand for these non-marketed amenities. A recognized drawback of the existing hedonic literature is that the models assume a myopic decision-maker. In this paper, we estimate a dynamic hedonic model and find that the average household is willing to pay $472 per year for a ten percent reduction in violent crime. In addition, we find that the traditional, myopic model suffers from a 21 percent negative bias.
Compensating Differentials for Sexual Harassment
Authors: Hersch Joni
Published: June 2011

Workplace sexual harassment is illegal, but many workers report that they have been sexually harassed. Exposure to the risk of sexual harassment may decrease productivity, which would reduce wages. Alternatively, workers may receive a compensating differential for exposure to sexual harassment, which would increase wages. Data on claims of sexual harassment filed with the Equal Employment Opportunity Commission are used to calculate the first measures of sexual harassment risks by industry, age group, and sex. Female workers face far higher sexual harassment risks. On balance, workers receive a compensating wage differential for exposure to the risk of sexual harassment.
Chipping away at the Glass Ceiling: Gender Spillovers in Corporate Leadership
Authors: Matsa David A , Miller Amalia R
Published: June 2011

This paper examines the role of women helping women in corporate America. Using a merged panel of directors and executives for large US corporations between 1997 and 2009, we find a positive association between the female share of the board of directors in the previous year and the female share among current top executives. The relationship's timing suggests that causality runs from boards to managers and not the reverse. This pattern of women helping women at the highest levels of firm leadership highlights the continued importance of a demand-side “glass ceiling” in explaining the slow progress of women in business.
Have Gender Gaps in Insurance Coverage and Access to Care Narrowed under Health Reform? Findings from Massachusetts
Authors: Long Sharon K , Stockley Karen , Shulman Shanna
Published: June 2011

Under its health reform legislation, Massachusetts has achieved near universal insurance coverage, along with significant gains in health care access and affordability. This paper examines the impacts of health reform in Massachusetts on differences in coverage, access, and affordability for women and men. We find that both women and men gained under health reform, with the gender gap in insurance coverage narrowed as men's coverage increased relative to that of women. However, the gaps in access and affordability of care have not narrowed—women in Massachusetts continue to report more unmet need for care and problems affording care than men.
International Migration and Gender Discrimination among Children Left Behind
Authors: Antman Francisca M
Published: June 2011

This paper considers how international migration of the head of household affects the allocation of resources toward boys relative to girls within households remaining in the home country. I address the endogeneity of migration with a differences-in-differences style regression model that compares those households in which migrants have already returned home with those in which migrants are still away. The evidence suggests that while the head of household is away a greater fraction of resources are spent on girls relative to boys, but upon his return, this pattern is reversed.
Promoting Recycling: Private Values, Social Norms, and Economic Incentives
Authors: Viscusi W. Kip , Huber Joel , Bell Jason
Published: June 2011

Evidence from a nationally representative sample of households illuminates the determinants of recycling behavior for plastic water bottles. Private values of the environment are influential in promoting recycling, as are personal norms for pro-environmental behavior. However, social norms with respect to the assessment of the household's recycling behaviors by others have little independent effect. Particularly influential are policies that create economic incentives to promote recycling either through state recycling laws that reduce the time and inconvenience costs of recycling or through bottle deposits. Effective policies can have a discontinuous effect at the individual level, transforming non-recyclers into avid recyclers.
The Diffusion of Energy Efficiency in Building
Authors: Kok Nils , McGraw Marquise , Quigley John M
Published: June 2011

We analyze the diffusion of buildings certified for energy efficiency across US property markets. Using a panel of 48 metropolitan areas (MSAs) observed over the last 15 years, we model the geographic patterns and dynamics of building certification, relating industry composition, changes in economic conditions, characteristics of the local commercial property market, and the presence of human capital, to the cross-sectional variation in energy-efficient building technologies and the diffusion of those technologies over time. Understanding the determinants and the rate at which energy-efficient building practices diffuse is important for designing policies to affect resource consumption in the built environment.
Do Residential Customers Respond to Hourly Prices? Evidence from a Dynamic Pricing Experiment
Authors: Wolak Frank A
Published: June 2011

This paper uses the results of a dynamic pricing experiment for households in the District of Columbia to determine whether the reduction in demand associated with an hourly price signal is economically different from the demand reduction associated with an equivalent price signal that is four times longer in duration. For both regular and all-electric customers, the percentage demand reduction associated with a given percentage increase in the hourly price is approximately equal to the percentage demand reduction associated with the same percentage price increase of a much longer duration.
Electricity Consumption and Durable Housing: Understanding Cohort Effects
Authors: Costa Dora L , Kahn Matthew E
Published: June 2011

We find that households living in California homes built in the 1960s and 1970s had high electricity consumption in 2000 relative to houses of more recent vintages because the price of electricity at the time of home construction was low. Homes built in the early 1990s had lower electricity consumption than homes of earlier vintages because the price of electricity was higher. The elasticity of the price of electricity at the time of construction was -0.22. As homes built between 1960 and 1989 become a smaller share of the housing stock, average household electricity purchases will fall.
Is an Automaker's Road to Bankruptcy Paved with Customers' Beliefs?
Authors: Hortaçsu Ali , Matvos Gregor , Shin Chaehee , Syverson Chad , Venkataraman Sriram
Published: June 2011

We explore the role the feedback loop between firms' financial health and consumers' demand for their products plays in the auto market. We construct a simple model of an automaker making pricing and debt service (continuation) decisions while recognizing that consumers are sensitive to whether it stays in business. We show that multiple equilibria can exist in such a model, and calibrate it to match stylized facts surrounding GM's recent bankruptcy. The results suggest that while the impact of financial distress on demand substantially reduced GM's profit, bank-run-like multiple equilibria do not appear likely in this market.
Consumers' Perceptions and Misperceptions of Energy Costs
Authors: Allcott Hunt
Published: June 2011

This paper presents three initial stylized facts from the Vehicle Ownership and Alternatives Survey (VOAS), a nationally representative survey that elicits consumers' beliefs about gasoline prices and the relative energy costs of autos with different fuel economy ratings. First, American consumers devote little attention to fuel costs when purchasing autos. Second, consistent with a cognitive bias called “MPG Illusion,” consumers underestimate the fuel cost differences between low-MPG vehicles and overestimate the differences between high-MPG vehicles. Third, Americans' mean and median expected future gas prices were above current prices and predictions of the futures market at the time of the survey. Although it is often argued that misperceived energy costs justify policies to encourage the sale of energy efficient durable goods, these results show that misperceptions and expectations that differ from market information could either increase or decrease energy efficiency.
Infotainment and citizens' political perceptions: Who's afraid of Polnia
Authors: Ferré-Pavia Carme , Gayà-Morlà Catalina
Published: May 2011

Our research focuses on a satirical political television programme called Polnia1broadcast on a public Catalan channel. Infotainment is a controversial subject in academic circles. After an academic review of the civic effects of the television satire on the general public, we provide data on infotainment in terms of its effects on the general public's understandings of Catalan and Spanish politics and politicians. Our study reflects viewers' understandings of Polnia and adds to the data on trends in European television. Two surveys and two focus groups were organized, involving a total of 1985 people with different social, political and viewing profiles. The results confirm the influence of infotainment in generating changes in peoples' perceptions of politics. There is a general agreement among the participants that the programme affects neither the voting turnout nor voting patterns. The results suggest that Polnia could reinforce the previous political malaise.
The myth of the natural in advertising
Authors: Salvador Pau
Published: May 2011

This article surveys how advertising language narrates nature, beginning with a review of the principal studies that have discussed the relationship between nature and advertising, often neglected by cultural studies. Applying an existing Floch model and the heuristic tools of narrative
semiotics, four prototypes of nature are established and illustrated according to representations and associated values. How we relate to nature is mediated by how it is treated in the media. There is no essential and immutable signifier of nature, but as many uses and forms as there are narratives
around it. The more the return to nature is discussed, the further we move from the natural world. This is one of the principal paradoxes constituting the cultural universe of late capitalism that burdens the individual with responsibility for recovering nature on an individual scale. This
new way of relating to nature has a privileged screen for viewing and analysis in promotional culture.
Children's funny art and the form it can take over time
Authors: Pitri Eliza
Published: May 2011

Children's untutored graphic representation is best understood as a form of visual communication rather than a form of perceptual development. A descriptive qualitative study was conducted in an attempt to investigate the specific visual and conceptual characteristics of children's
humorous images. The participants of the study were 578 children between the ages of 4.5 and 12. They were asked to draw something funny and describe why what they drew was funny. What the children drew and said was coded, recorded and analysed using both qualitative and quantitative methods
for different purposes, based on the following questions: Which are the themes of children's humorous art Where are these themes derived from How are the themes of children's humorous art presented The use of statistical analysis helped track correlations between age groups, and different
categories and characteristics of children's humorous art. No significant gender differences were found in children's humorous images.
Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions
Authors: Sonderegger Walter , Vecellio Manuele , Zwicker Pascal , Niemz Peter
Published: June 2011

The combined bound water and water vapour diffusion of wood is of great interest in the field of building physics. Due to swelling stresses, the steady-state-determined diffusion coefficient clearly differs from the unsteady-state-determined diffusion coefficient. In this study, both diffusion coefficients and the water vapour resistance factor of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) were investigated for the principal anatomical directions (radial, tangential and longitudinal) and in 15° steps between these directions. The values were determined with the cup method as the basic principle. The unsteady-state-determined diffusion coefficient is, independent of the direction, about half that of the steady-state-determined diffusion coefficient. Both diffusion coefficients are about two to three times higher for spruce than for beech. They are up to 12 times higher in the longitudinal direction than perpendicular to the grain for spruce, and up to 15 times higher for beech. With increasing moisture content, the diffusion coefficients exponentially increase. The water vapour resistance factor shows converse values to the diffusion coefficients.
Time-optimal reconstruction of Riemannian manifold via boundary electromagnetic measurements
Authors: Belishev Mikhail I. , Demchenko Maxim N.
Published: June 2011

A dynamical Maxwell system is et
= curl h, ht
= – curl e in Ω × (0, T), e|
t=0 = 0, h|
t=0 = 0 in Ω, eθ
= ƒ in ∂Ω × [0, T], where Ω is a smooth compact oriented 3-dimensional Riemannian manifold with boundary, (·)
θ
is a tangent component of a vector at the boundary, e = e
ƒ (x, t) and h = h
ƒ (x, t) are the electric and magnetic components of the solution. One associates with this system a response operator RT
: ƒ ↦ ν ∧ h
ƒ|
∂Ω×(0,T), where ν is an outward normal to ∂Ω.

The time-optimal setup of the inverse problem, which is relevant to the finiteness of the wave speed propagation, is as follows: given R
2T
to recover the part Ω
T
≔ {x ∈ Ω| dist(x, ∂Ω) < T} of the manifold. As was shown by Belishev, Isakov, Pestov, Sharafutdinov (Doklady Mathematics 61: 353–356, 2000), for T small enough the operator R
2T
determines Ω
T
uniquely up to isometry.

Here we prove that uniqueness holds for arbitrary T > 0 and provide a procedure that recovers Ω
T
from R
2T
. Our approach is a version of the boundary control method (Belishev, 1986).
A Silent Synapse-Based Mechanism for Cocaine-Induced Locomotor Sensitization
Authors: Brown Travis E. , Lee Brian R. , Mu Ping , Ferguson Deveroux , Dietz David , Ohnishi Yoshinori N. , Lin Ying , Suska Anna , Ishikawa Masago , Huang Yanhua H. , Shen Haowei , Kalivas Peter W. , Sorg Barbara A. , Zukin R. Suzanne , Nestler Eric J. , Dong Yan , Schlüter Oliver M.
Published: June 2011

Locomotor sensitization is a common and robust behavioral alteration in rodents whereby following exposure to abused drugs such as cocaine, the animal becomes significantly more hyperactive in response to an acute drug challenge. Here, we further analyzed the role of cocaine-induced silent synapses in the nucleus accumbens (NAc) shell and their contribution to the development of locomotor sensitization. Using a combination of viral vector-mediated genetic manipulations, biochemistry, and electrophysiology in a locomotor sensitization paradigm with repeated, daily, noncontingent cocaine (15 mg/kg) injections, we show that dominant-negative cAMP-element binding protein (CREB) prevents cocaine-induced generation of silent synapses of young (30 d old) rats, whereas constitutively active CREB is sufficient to increase the number of NR2B-containing NMDA receptors (NMDARs) at synapses and to generate silent synapses. We further show that occupancy of CREB at the NR2B promoter increases and is causally related to the increase in synaptic NR2B levels. Blockade of NR2B-containing NMDARs by administration of the NR2B-selective antagonist Ro256981 directly into the NAc, under conditions that inhibit cocaine-induced silent synapses, prevents the development of cocaine-elicited locomotor sensitization. Our data are consistent with a cellular cascade whereby cocaine-induced activation of CREB promotes CREB-dependent transcription of NR2B and synaptic incorporation of NR2B-containing NMDARs, which generates new silent synapses within the NAc. We propose that cocaine-induced activation of CREB and generation of new silent synapses may serve as key cellular events mediating cocaine-induced locomotor sensitization. These findings provide a novel cellular mechanism that may contribute to cocaine-induced behavioral alterations.
Grasping-Related Functional Magnetic Resonance Imaging Brain Responses in the Macaque Monkey
Authors: Nelissen Koen , Vanduffel Wim
Published: June 2011

Research in recent decades has suggested the existence of a dedicated brain network devoted to the organization and execution of grasping, one of the most important and skilled movements of primates. Grasping an object requires the transformation of intrinsic object properties such as size, orientation, and shape into an appropriate motor scheme shaping the hand. Although electrophysiological recordings in the monkey model have proven invaluable for gaining insights into the neuronal substrate underlying this complex behavior, knowledge concerning the existence and organization of a similar system in the human brain is derived mainly from imaging studies. Here, we present for the first time functional magnetic resonance imaging (fMRI) of brain activity while macaque monkeys performed reaching and grasping movements in a 3 tesla MR scanner. Grasping in the dark (compared with reaching) yielded significant activations in anterior intraparietal area and ventral premotor area F5, in addition to area PFG in the rostral inferior parietal lobule, somatosensory areas (SI, SII, area 5), and the hand field of F1. Whole-brain macaque fMRI motor studies will be instrumental in establishing possible homologies concerning grasping organization in the human and monkey brains, bridging the gap between human imaging and monkey electrophysiology.
Striatal-Enriched Protein Tyrosine Phosphatase Expression and Activity in Huntington's Disease: A STEP in the Resistance to Excitotoxicity
Authors: Saavedra Ana , Giralt Albert , Rué Laura , Xifró Xavier , Xu Jian , Ortega Zaira , Lucas José J. , Lombroso Paul J. , Alberch Jordi , Pérez-Navarro Esther
Published: June 2011

Striatal-enriched protein tyrosine phosphatase (STEP) is highly expressed in striatal projection neurons, the neuronal population most affected in Huntington's disease. Here, we examined STEP expression and phosphorylation, which regulates its activity, in N-terminal exon-1 and full-length mutant huntingtin mouse models. R6/1 mice displayed reduced STEP protein levels in the striatum and cortex, whereas its phosphorylation was increased in the striatum, cortex, and hippocampus. The early increase in striatal STEP phosphorylation levels correlated with a deregulation of the protein kinase A pathway, and decreased calcineurin activity at later stages further contributes to an enhancement of STEP phosphorylation and inactivation. Accordingly, we detected an accumulation of phosphorylated ERK2 and p38, two targets of STEP, in R6/1 mice striatum at advanced stages of the disease. Activation of STEP participates in excitotoxic-induced cell death. Because Huntington's disease mouse models develop resistance to excitotoxicity, we analyzed whether decreased STEP activity was involved in this process. After intrastriatal quinolinic acid (QUIN) injection, we detected higher phosphorylated STEP levels in R6/1 than in wild-type mice, suggesting that STEP inactivation could mediate neuroprotection in R6/1 striatum. In agreement, intrastriatal injection of TAT–STEP increased QUIN-induced cell death. R6/2, Tet/HD94, and HdhQ7/Q111mice striatum also displayed decreased STEP protein and increased phosphorylation levels. In Tet/HD94 mice striatum, mutant huntingtin transgene shutdown reestablished STEP expression. In conclusion, the STEP pathway is severely downregulated in the presence of mutant huntingtin and may participate in compensatory mechanisms activated by striatal neurons that lead to resistance to excitotoxicity.
Dorsal and Ventral Parietal Contributions to Spatial Orienting in the Human Brain
Authors: Chica Ana B. , Bartolomeo Paolo , Valero-Cabré Antoni
Published: June 2011

Influential functional magnetic resonance imaging (fMRI)-based models have involved a dorsal frontoparietal network in the orienting of both endogenous and exogenous attention, and a ventral system in attentional reorienting to task-relevant events. Nonetheless, given the low temporal resolution and susceptibility to epiphenomenal activations of fMRI, such depictions remain highly debated. We hereby benefited from the high temporal resolution and causal power of event-related transcranial magnetic stimulation to explore the implications of key dorsal and ventral parietal regions in those two types of attention. We provide for the first time causal evidence of right intraparietal sulcus involvement in both types of attentional orienting, while we link the temporoparietal junction with the orienting of exogenous but not endogenous spatial attention.
Visual Experience-Dependent Maturation of Correlated Neuronal Activity Patterns in a Developing Visual System
Authors: Xu Heng , Khakhalin Arseny S. , Nurmikko Arto V. , Aizenman Carlos D.
Published: June 2011

The functional properties of neural circuits become increasingly robust over development. This allows circuits to optimize their output in response to a variety of input. However, it is not clear whether this optimization is a function of hardwired circuit elements, or whether it requires neural experience to develop. We performed rapidin vivoimaging of calcium signals from bulk-labeled neurons in theXenopus laevisoptic tectum to resolve the rapid spatiotemporal response properties of populations of developing tectal neurons in response to visual stimuli. We found that during a critical time in tectal development, network activity becomes increasingly robust, more correlated, and more synchronous. These developmental changes require normal visual input during development and are disrupted by NMDAR blockade. Our data show that visual activity and NMDAR activation are critical for the maturation of tectal network dynamics during visual system development.
Multiple Routes from Occipital to Temporal Cortices during Reading
Authors: Richardson Fiona M. , Seghier Mohamed L. , Leff Alex P. , Thomas Michael S. C. , Price Cathy J.
Published: June 2011

Contemporary models of the neural system that supports reading propose that activity in a ventral occipitotemporal area (vOT) drives activity in higher-order language areas, for example, those in the posterior superior temporal sulcus (pSTS) and anterior superior temporal sulcus (aSTS). We used fMRI with dynamic causal modeling (DCM) to investigate evidence for other routes from visual cortex to the left temporal lobe language areas. First we identified activations in posterior inferior occipital (iO) and vOT areas that were more activated for silent reading than listening to words and sentences; and in pSTS and aSTS areas that were commonly activated for reading relative to false-fonts and listening to words relative to reversed words. Second, in three different DCM analyses, we tested whether visual processing of words modulates activity from the following: (1) iO→vOT, iO→pSTS, both, or neither; (2) vOT→pSTS, iO→pSTS, both or neither; and (3) pSTS→aSTS, vOT→aSTS, both, or neither. We found that reading words increased connectivity (1) from iO to both pSTS and vOT; (2) to pSTS from both iO and vOT; and (3) to aSTS from both vOT and pSTS. These results highlight three potential processing streams in the occipitotemporal cortex: iO→pSTS→aSTS; iO→vOT→aSTS; and iO→vOT→pSTS→aSTS. We discuss these results in terms of cognitive models of reading and propose that efficient reading relies on the integrity of all these pathways.
Role of Guanylyl Cyclase Modulation in Mouse Cone Phototransduction
Authors: Sakurai Keisuke , Chen Jeannie , Kefalov Vladimir J.
Published: June 2011

A negative phototransduction feedback in rods and cones is critical for the timely termination of their light responses and for extending their function to a wide range of light intensities. The calcium feedback mechanisms that modulate phototransduction in rods have been studied extensively. However, the corresponding modulation mechanisms that enable cones to terminate rapidly their light responses and to adapt in bright light, properties critical for our daytime vision, are still not understood. In cones, calcium feedback to guanylyl cyclase is potentially a key step in phototransduction modulation. The guanylyl cyclase activity is modulated by the calcium-binding guanylyl cyclase activating proteins (GCAP1 and GCAP2). Here, we used single-cell and transretinal recordings from mouse to determine how GCAPs modulate dark-adapted responses as well as light adaptation in mammalian cones. Deletion of GCAPs increased threefold the amplitude and dramatically prolonged the light responses in dark-adapted mouse cones. It also reduced the operating range of mouse cones in background illumination and severely impaired their light adaptation. Thus, GCAPs exert powerful modulation on the mammalian cone phototransduction cascade and play an important role in setting the functional properties of cones in darkness and during light adaptation. Surprisingly, despite their better adaptation capacity and wider calcium dynamic range, mammalian cones were modulated by GCAPs to a lesser extent than mammalian rods. We conclude that a disparity in the strength of GCAP modulation cannot explain the differences in the dark-adapted properties or in the operating ranges of mammalian rods and cones.
The Rho1 GTPase Acts Together With a Vacuolar Glutathione S-Conjugate Transporter to Protect Yeast Cells From Oxidative Stress
Authors: Lee Mid Eum , Singh Komudi , Snider Jamie , Shenoy Archana , Paumi Christian M , Stagljar Igor , Park Hay-Oak
Published: May 2011

Maintenance of redox homeostasis is critical for the survival of all aerobic organisms. In the budding yeast Saccharomyces cerevisiae, as in other eukaryotes, reactive oxygen species (ROS) are generated during metabolism and upon exposure to environmental stresses. The abnormal production of ROS triggers defense mechanisms to avoid the deleterious consequence of ROS accumulation. Here, we show that the Rho1 GTPase is necessary to confer resistance to oxidants in budding yeast. Temperature-sensitive rho1 mutants (rho1ts) are hypersensitive to oxidants and exhibit high accumulation of ROS even at a semipermissive temperature. Rho1 associates with Ycf1, a vacuolar glutathione S-conjugate transporter, which is important for heavy metal detoxification in yeast. Rho1 and Ycf1 exhibit a two-hybrid interaction with each other and form a bimolecular fluorescent complex on the vacuolar membrane. A fluorescent-based complementation assay suggests that the GTP-bound Rho1 associates with Ycf1 and that their interaction is enhanced upon exposure to hydrogen peroxide. The rho1ts mutants also exhibit hypersensitivity to cadmium, while cells carrying a deletion of YCF1 or mutations in a component of the Pkc1–MAP kinase pathway exhibit little or minor sensitivity to oxidants. We thus propose that Rho1 protects yeast cells from oxidative stress by regulating multiple downstream targets including Ycf1. Since both Rho1 and Ycf1 belong to highly conserved families of proteins, similar mechanisms may exist in other eukaryotes.
Cleft Lip and Palate: Effects on Neonatal Care
Authors: Tighe David , Petrick Laima , Cobourne Martyn T. , Rabe Heike
Published: June 2011

This article reviews clefts involving the lip with or without the palate (CLP±P) and isolated clefts of the palate (CP) from genetic and epidemiologic perspectives. Particular attention is given to management strategies to address issues arising in the neonatal period before the deformity is treated. The multidisciplinary team is especially important in tailoring care to the needs of the child. Regional specialist services are recommended during early childhood for infants who have CLP±P or CP.
Immunogenicity and Safety of H influenzae Type b–N meningitidis C/Y Conjugate Vaccine in Infants
Authors: Bryant Kristina A. , Marshall Gary S. , Marchant Colin D. , Pavia-Ruiz Noris , Nolan Terry , Rinderknecht Stephen , Blatter Mark , Aris Emmanuel , Lestrate Pascal , Boutriau Dominique , Friedland Leonard R. , Miller Jacqueline M.
Published: May 2011

BACKGROUND:

Meningococcal disease incidence is highest in children younger than 2 years of age, yet there is no US-licensed vaccine for this age group. A phase III study evaluated the immunogenicity and safety of an investigational Haemophilus influenzae type b (Hib)–Neisseria meningitidis serogroups C and Y-tetanus toxoid conjugate vaccine (HibMenCY).

MATERIALS AND METHODS:

A total of 4180 infants were randomly assigned to receive the HibMenCY at the ages of 2, 4, 6, and 12 to 15 months or the licensed Hib tetanus toxoid conjugate vaccine (ActHIB) at 2, 4, and 6 months and Hib conjugated to N meningitidis outer membrane protein (PedvaxHIB) at 12 to 15 months. Routinely scheduled vaccines were coadministered. Serum bactericidal activity using human complement and anti–polyribosylribitol phosphate antibodies were assessed in 991 subjects. Local and systemic adverse reactions were recorded for 4 days after each dose.

RESULTS:

The percentage of HibMenCY recipients with serum bactericidal assay using human complement titers of 1:8 or higher after dose 3 was 98.8% for N meningitidis serogroup C (MenC) and 95.8% for N meningitidis serogroup Y (MenY). After dose 4, the percentages were 98.5% and 98.8%, respectively. The percentage of HibMenCY recipients with postdose 3 anti-polyribosylribitol phosphate antibody levels of ≥1.0 μg/mL was noninferior to that of control (96.3% vs 91.2%). After dose 4, MenC and MenY serum bactericidal assay using human complement antibody titers increased 12-fold over pre–dose 4 levels. Incidence of pain, redness, and swelling at the HibMenCY injection sites tended to be lower than with Hib type b after the first 3 doses and after the fourth dose. Rates of systemic symptoms were similar across groups.

CONCLUSIONS:

The HibMenCY was immunogenic against MenC and MenY and induced anti–polyribosylribitol phosphate antibody levels noninferior to those of licensed Hib conjugate vaccine. The safety profile of the HibMenCY was clinically acceptable and comparable to Hib conjugate vaccine.
Early Childhood Development of Late-Preterm Infants: A Systematic Review
Authors: McGowan Jennifer E. , Alderdice Fiona A. , Holmes Valerie A. , Johnston Linda
Published: May 2011

CONTEXT:

Late-preterm infants (LPIs) born at 34 to 36 weeks' gestation are increasingly regarded as being at risk for adverse developmental outcomes. To date, the early childhood development of LPIs has not been systematically considered.

OBJECTIVE:

To undertake a broad examination of literature relating to early childhood development at the ages of 1 to 7 years of LPIs born at 34 to 36 weeks' gestation.

METHODS:

We conducted a systematic review of early childhood outcomes in LPIs by using 9 electronic databases (January 1980 to March 2010). Bibliographies were reviewed. After examination of abstracts, ineligible studies were excluded. A specifically designed data-extraction form was used. The methodologic quality of included studies was assessed by using well-documented quality-appraisal guidelines.

RESULTS:

Of 4581 studies, 10 (3 prospective and 7 retrospective cohort) were included. Studies were heterogeneous, and poorer outcomes were reported among LPIs in relation to neurodevelopmental disabilities, educational ability, early-intervention requirements, medical disabilities, and physical growth in comparison to term-born children. No identified study used healthy nonadmitted LPIs as a comparison group for admitted LPIs.

CONCLUSIONS:

Evidence suggests that LPIs are at increased risk of adverse developmental outcomes and academic difficulties up to 7 years of age in comparison to term infants. An infant control group matched for gestational age has not been used; thus, for LPIs, the effect of neonatal admission on longer-term outcomes has not been fully explored. Systematic measurement of early childhood outcomes is lacking, and focused long-term follow-up studies are needed to investigate early childhood development after late-preterm birth.
Growth or development?
Authors: Bródy A.
Published: June 2011

The task of economics is apparently changing. After confronting the limits to growth, the economic interests, methods and thoughts, even its use of words and concepts are slowly but persistently modified. The discussion of “equilibrium” is replaced by the concern for a “sustainable path”. Instead of finding out how to produce “more” it looks for “better”, “cheaper” and “recyclable” commodities. Labor saving serves by and large the reduction of the working week and transformation of the life-cycle instead of surplus-production. The markets of developed countries are more easily glutted and their recessions deeper. The ever louder and more aggressive marketing attests to all this. It is high time to renew our old ways, to revisit the aged analytical and forecasting models. The renovation of obsolete concepts is rendered necessary to facilitate the introduction of an orderly and planned future of prudence. This investigation focuses less on the seldom, perhaps never occupied point of equilibrium, rather on the behavior and motion of the economic systems in its vicinity.
FURTHER EVALUATION OF ANTECEDENT INTERVENTIONS ON COMPLIANCE: THE EFFECTS OF RATIONALES TO INCREASE COMPLIANCE AMONG PRESCHOOLERS
Authors: Wilder David A. , Allison Janelle , Nicholson Katie , Abellon O. Elizabeth , Saulnier Renee
Published: June 2011

Functional analyses were conducted to identify reinforcers for noncompliance exhibited by 6 young children. Next, the effects of rationales (statements that describe why a child should comply with a caregiver‐delivered instruction) were evaluated. In Experiment 1, 3 participants received the rationales immediately after the therapist's instruction. In Experiment 2, 3 additional participants received more practical rationales immediately before the therapist's instruction. The results indicate that rationales were ineffective for all 6 children. A guided compliance procedure increased compliance for 1 child; contingent access to preferred items with or without response cost increased compliance for the other participants. Although levels of problem behavior varied within and across participants, they were often higher in the rationale and guided compliance conditions.
A COMPARISON OF THE EFFECTS OF PROVIDING ACTIVITY AND MATERIAL CHOICE TO CHILDREN WITH AUTISM SPECTRUM DISORDERS
Authors: Ulke‐Kurkcuoglu Burcu , Kircaali‐Iftar Gonul
Published: June 2011

The present study compares the effects of providing choice between activities or between materials for completion of activities on the on‐task behavior of 4 boys with autism spectrum disorders. Results showed that the participants displayed higher levels of on‐task behavior during the choice conditions than in the no‐choice condition. However, the type of choice opportunity did not seem to have a differential effect.