Computation of Λˉ\bar{\Lambda} and λ1\lambda_1 with Lattice QCD

We pursue a new method, based on lattice QCD, for determining the quantities $\bar{\Lambda}$, $\lambda_1$, and $\lambda_2$ of heavy-quark effective theory. We combine Monte Carlo data for the meson mass spectrum with perturbative calculations of the short-distance behavior, to extract $\bar{\Lambda}$ and $\lambda_1$ from a formula from HQET. Taking into account uncertainties from fitting the mass dependence and from taking the continuum limit, we find $\bar{\Lambda} = 0.68{+0.02}_{-0.12} \text{GeV}$ and $\lambda_1 = -(0.45 \pm 0.12) \text{GeV}^2$ in the quenched approximation.Comment: 7 pp, 4 figs (in v2 Fig. 4 now shows Ref. 13, as advertised); in v3 error in BLM scale is correcte

Increasing Returns to Education and Progress towards a College Degree

Returns to college have increased, but graduation rates have changed relatively little. Modifying a human capital model of college enrollment to endogenize time-to-graduation, we predict that higher returns to education will both speed graduation and increase enrollment. Some of those new entrants may, however, take longer to graduate. Using the 1989 and 1995 Beginning Postsecondary Studies, we employ a multinomial logit to model the association between individual and family characteristics, and five-year college outcomes: graduation, continued enrollment, and non-enrollment. Between cohort differences arise either because the characteristics of those entering college are different or because the relations between characteristics and outcomes have changed. We utilize a Oaxaca-Blinder style decomposition to distinguish between these two alternatives, attributing differences in characteristics to newly attracted students and differences in the relations between characteristics and outcomes to historically attracted students behaving differently. It is changes in behavior that explain the increased progress we observe.Higher Education, Graduation Rates, Persistence

Reported Progress under the Student Right-to-Know Act: How Reliable is It?

The Student Right-to-Know Act requires colleges to provide institution-specific information on graduation rates for students initially enrolling full-time in the fall term. Not all students enroll in that fashion, especially at two-year institutions. We use data on degree-seeking students from the 1996/2001 Beginning Post-Secondary Survey to identify students for whom statistics are and are not reportable under the Act and to track their progress. Results indicate the published progress rates are substantially higher than the progress rates for the non-reportable populations, whether students enter a two-year or a four-year institution. While progress rates for the two samples are significantly correlated within four-year institutions, they are not within two-year institutions. For those beginning at two-year institutions, the progress rates reported under the Student Right-to-Know Act are indicative of neither their absolute nor their relative (cross-institution) probability of success. Policy makers and prospective students will not make efficient decisions without better information.Efficiency, Resource Allocation, Graduation

Quantum imaging of spin states in optical lattices

We investigate imaging of the spatial spin distribution of atoms in optical lattices using non-resonant light scattering. We demonstrate how scattering spatially correlated light from the atoms can result in spin state images with enhanced spatial resolution. Furthermore, we show how using spatially correlated light can lead to direct measurement of the spatial correlations of the atomic spin distribution

NAVIGATING U.S. FISHERY MANAGEMENT INTO THE 21ST CENTURY

Resource /Energy Economics and Policy,

THE OPTIMAL QUANTITY OF LAND IN AGRICULTURE: DISCUSSION

Land Economics/Use,

The Coase Theorem, or the Coasian Lens? An Application to GMO Regulation

We develop a property rights-transaction costs framework called the Coasian Lens (CL). We argue the CL captures Coase's seminal ideas (1937; 1960) more closely than the Coase Theorem. We use the CL to examine how regulation of genetically modified organisms (GMOs) may affect contract structures in the global agri-food chain.Research and Development/Tech Change/Emerging Technologies,

Heat and Mass Transfer in Cold Regions Soils

The work upon which this report is based was made possible by a cooperative aid agreement between the U.S. Forest Service, Institute of Northern Forestry, Fairbanks, Alaska, and the Institute of Water Resources, University of Alaska. Contributions to this study were also made by the University of California at Davis and Ohio State University. The collection of winter data on pore pressures was made possible by a separate grant by the Office of Water Research and Technology (project A-053 ALAS)

Photocatalytic production of organic compounds from CO and H2O in a simulated Martian atmosphere

[14C]CO2 and [14C]organic compounds are formed when a mixture of [14C]CO and water vapor diluted in [12C]CO2 or N2 is irradiated with ultraviolet light in the presence of soil or pulverized vycor substratum. The [14C]CO2 is recoverable from the gas phase, the [14C]organic products from the substratum. Three organic products have been tentatively identified as formaldehyde, acetaldehyde, and glycolic acid. The relative yields of [14C]CO2 and [14C]organics are wavelength- and surface-dependent. Conversion of CO to CO2 occurs primarily at wavelengths shorter than 2000 angstrom, apparently involves the photolysis of water, and is inhibited by increasing amounts of vycor substratum. Organic formation occurs over a broad spectral range below 3000 angstrom and increases with increasing amounts of substratum. It is suggested that organic synthesis results from adsorption of CO and H2O on surfaces, with excitation of one or both molecules occurring at wavelengths longer than those absorbed by the free gases. This process may occur on Mars and may have been important on the primitive earth