The Neural Correlated of Subjective Value During Intertemporal Choice

Neuroimaging studies of decision-making have generally related neural activity to objective measures (such as reward magnitude, probability or delay), despite choice preferences being subjective. However, economic theories posit that decision-makers behave as though different options have different subjective values. Here we use functional magnetic resonance imaging to show that neural activity in several brain regions—particularly the ventral striatum, medial prefrontal cortex and posterior cingulate cortex—tracks the revealed subjective value of delayed monetary rewards. This similarity provides unambiguous evidence that the subjective value of potential rewards is explicitly represented in the human brain

The Neurobiology of Decision: Consensus and Controversy

We review and synthesize recent neurophysiological studies of decision making in humans and nonhuman primates. From these studies, the basic outline of the neurobiological mechanism for primate choice is beginning to emerge. The identified mechanism is now known to include a multicomponent valuation stage, implemented in ventromedial prefrontal cortex and associated parts of striatum, and a choice stage, implemented in lateral prefrontal and parietal areas. Neurobiological studies of decision making are beginning to enhance our understanding of economic and social behavior as well as our understanding of significant health disorders where people\u27s behavior plays a key role

Neuroeconomic Studies of Impulsivity: Now or Just as Soon as Possible?

Existing behavioral studies of intertemporal choice suggest that both human and animal choosers are impulsive. One possible explanation for this is that they discount future gains in a hyperbolic or quasi-hyperbolic fashion (David I. Laibson 1997; Shane Frederick, George Loewenstein, and Ted O’Donoghue 2002). This observation stands in contrast to standard normative theory, which predicts exponential discounting for any single maximizing agent (Robert H. Strotz 1956). This disparity between empirical and normative approaches is typically explained by proposing that human choosers suffer from inner conflict, balancing an impulse for an immediate gratification against other forces calling for delayed gratification (Richard H. Thaler and H. M. Shefrin 1981; Laibson 1997; Drew Fudenberg and David K. Levine 2006; Jess Benhabib and Alberto Bisin 2005; B. Douglas Bernheim and Antonio Rangel 2004; Faruk Gul and Wolfgang Pesendorfer 2001). We hoped to better understand both the behavioral and algorithmic roots of this phenomenon by conducting a series of behavioral and neurobiological experiments on intertemporal choice. The results of our behavioral experiments deviate significantly from the predictions of both normative and inner conflict models. The results of our neurobiological experiments provide new algorithmic insights into the mechanisms of intertemporal choice

CubeSat Measures World's First Ice Cloud Map to Support Climate Research

Virginia Diodes, Inc. received NASA SBIR Awards to fund research and development for a lesser developed region of the electromagnetic spectrumterahertz waves. Their work led to funding from NASA ESTO, and the resulting CubeSat (named IceCube) captured the worlds first ice cloud map, which will contribute to our understanding of Earths climat

A Note On Job Market Conditions And Students Academic Performance

This paper presents a model of student effort and resulting grade performance under varying labor market conditions. Following previous studies that have found a negative relationship between the expected income and grades by discipline, we extend the analysis to the effect of changing labor market conditions on student effort and the resulting changes in the average grades. The empirical results support the theoretical models conclusion that reduced employment opportunities result in higher average grades by discipline

Nickel-doped ceria nanoparticles : the effect of annealing on room temperature ferromagnetism

Nickel-doped cerium dioxide nanoparticles exhibit room temperature ferromagnetism due to high oxygen mobility within the doped CeO2 lattice. CeO2 is an excellent doping matrix as it can lose oxygen whilst retaining its structure. This leads to increased oxygen mobility within the fluorite CeO2 lattice, leading to the formation of Ce3+ and Ce4+ species and hence doped ceria shows a high propensity for numerous catalytic processes. Magnetic ceria are important in several applications from magnetic data storage devices to magnetically recoverable catalysts. We investigate the effect doping nickel into a CeO2 lattice has on the room temperature ferromagnetism in monodisperse cerium dioxide nanoparticles synthesised by the thermal decomposition of cerium(III) and nickel(II) oleate metal organic precursors before and after annealing. The composition of nanoparticles pre- and post-anneal were analysed using: TEM (transmission electron microscopy), XPS (X-ray photoelectron spectroscopy), EDS (energy-dispersive X-ray spectroscopy) and XRD (X-ray diffraction). Optical and magnetic properties were also studied using UV/Visible spectroscopy and SQUID (superconducting interference device) magnetometry respectively

Interferometric Rayleigh Scattering Measurement System

A method and apparatus for performing simultaneous multi-point measurements of multiple velocity components in a gas flow is described. Pulses of laser light are directed to a measurement region of unseeded gas to produce Rayleigh or Mie scattered light in a plurality of directions. The Rayleigh or Mie scattered light is collected from multiple directions and combined in a single collimated light beam. The Rayleigh or Mie scattered light is then mixed together with a reference laser light before it is passed through a single planar Fabry-Perot interferometer for spectral analysis. At the output of the interferometer, a high-sensitivity CCD camera images the interference fringe pattern. This pattern contains the spectral and spatial information from both the Rayleigh scattered light and the reference laser light. Interferogram processing software extracts and analyzes spectral profiles to determine the velocity components of the gas flow at multiple points in the measurement region. The Rayleigh light rejected by the interferometer is recirculated to increase the accuracy and the applicability of the method for measurements at high temperatures without requiring an increase in the laser energy

Epilimnetic Phytoplankton and Zooplankton Biomass and Species Composition In Lake Ontario, 1986 to 1992.

Results of the Food Web Workshop II (Hartig et al. 1991) indicated that Lake Ontario may be the next Great Lake after Lake Michigan to demonstrate the effects of changing nutrient levels and food web controls. Total phosphorus loads into the lake declined by 80% since 1972 and have approached the target loading set by the Great Lakes Water Quality Agreements between the United States and Canada. Spring total phosphorus levels declined from 25 to 14 IlglL between 1971 and the late 1980s and are currently below 10 Ilg/L. Although declines in chlorophyll-a were relatively low and transparency has not changed appreciably, there is some evidence that algal biomass has declined. Besides changes in nutrient concentrations, changes in fish abundance has occurred as alewife, slimy sculpin and smelt biomass have decreased, while stocking of coho and chinook salmon increased from 40,000 to 5.4 million from 1968 to 1984 (Hartig et al.. 1991). In 1993, the rate of salmonine stocking was reduced (Luckey 1994). These changes in nutrient status and in the food web of the lake, and the potential for further appreciable change in the biota of Lake Ontario, have directed attention to the long-term data sets of phytoplankton and zooplankton collected by the Great Lakes National Program Office of the U. S. Environmental Protection Agency as indicators of quantitative and compositional changes in plankton community structure. Phytoplankton, which have short carbon turnover rates, are sensitive to water quality conditions and to grazing by zooplankton and thus respond rapidly to perturbations of the lake ecosystem. The determination of phytoplankton abundance and species composition is one method to trace long-term changes in lakes (Munawar and Munawar 1982, Makarewicz 1993, Makarewicz and Bertram 1991). Similarly, whether aquatic ecosystems are perturbed by changes in the top predator fish that 2 cascade down the food web or by nutrients or by other stressors that are expressed from the first trophic level upward, the zooplankton are sensitive integrators of such changes (McNaught and Buzzard 1973). They have also proved useful for complementing phytoplankton data to assess the effects of water quality (Gannon and Sternberger 1978) and fish populations on biota (e.g. Brooks and Dodson 1965). The phytoplankton and zooplankton data sets collected by EPA\u27s Great Lakes National Program Office provide such information and support the International J oint Commission\u27s call for more and better information through monitoring and research on components of the Lake Ontario food web (Hartig et al. 1991). In this study, data about the 1986-92 spring and summer phytoplankton and zooplankton assemblages make it possible to examine the historical, geographic, and seasonal relationships prevailing in Lake Ontario and to compare them, where possible, to previous studies