On the uselessness of quantum queries

Given a prior probability distribution over a set of possible oracle functions, we define a number of queries to be useless for determining some property of the function if the probability that the function has the property is unchanged after the oracle responds to the queries. A familiar example is the parity of a uniformly random Boolean-valued function over $\{1,2,...,N\}$, for which $N-1$ classical queries are useless. We prove that if $2k$ classical queries are useless for some oracle problem, then $k$ quantum queries are also useless. For such problems, which include classical threshold secret sharing schemes, our result also gives a new way to obtain a lower bound on the quantum query complexity, even in cases where neither the function nor the property to be determined is Boolean

Single query learning from abelian and non-abelian Hamming distance oracles

We study the problem of identifying an n-bit string using a single quantum query to an oracle that computes the Hamming distance between the query and hidden strings. The standard action of the oracle on a response register of dimension r is by powers of the cycle (1...r), all of which, of course, commute. We introduce a new model for the action of an oracle--by general permutations in S_r--and explore how the success probability depends on r and on the map from Hamming distances to permutations. In particular, we prove that when r = 2, for even n the success probability is 1 with the right choice of the map, while for odd n the success probability cannot be 1 for any choice. Furthermore, for small odd n and r = 3, we demonstrate numerically that the image of the optimal map generates a non-abelian group of permutations.Comment: 14 page

The Effects of Welfare and Tax Reform: The Material Well-Being of Single Mothers in the 1980s and 1990s

The tax and welfare programs that provide income and in-kind benefits to single mothers have changed dramatically in recent years. These changes began as far back as the mid-1980s and culminated with the 1996 welfare law that 'ended welfare as we knew it.' These tax and welfare changes have sharply increased the employment of single mothers and cut welfare rolls. However, little is know about the effects of these policy changes on the living conditions of single mothers and their children. Studies of those leaving welfare have found that a substantial percentage have problems paying rent, purchasing enough food, and paying utility bills. Other studies have found a decline in income among the worst-off single mothers. The goal of this paper is to examine the material well-being of single mothers and their families before and soon after welfare reform. Using data from two nationally representative household surveys we examine the consumption patterns of single mothers and their families. We find that the material conditions of single mothers did not decline in recent years, either in absolute terms or relative to single childless women or married mothers. In most cases, our evidence suggests that the material conditions of single mothers have improved slightly, even for highly disadvantaged single mothers.

Further Results on Measuring the Well-Being of the Poor Using Income and Consumption

In the U.S., analyses of poverty rates and the effects of anti-poverty programs rely almost exclusively on income data. In earlier work (Meyer and Sullivan, 2003) we emphasized that conceptual arguments generally favor using consumption data to measure the well-being of the poor, and, on balance, data quality issues favor consumption in the case of single mothers. Our earlier work did not show that income and consumption differ in practice. Here we further examine data quality issues and show that important conclusions about recent trends depend on whether one uses consumption or income. Changes in the distribution of resources for single mothers differ sharply in recent years depending on whether measured by income or consumption. Measures of overall and sub-group poverty also sharply differ. In addition to examining broader populations and a longer time period, we also consider new dimensions of data quality such as survey and item nonresponse, imputation, and precision. Finally, we demonstrate the flaws in a recent paper that compares income and consumption data.

The Complex Interstellar Na I Absorption toward h and Chi Persei

Recent high spatial and spectral resolution investigations of the diffuse interstellar medium (ISM) have found significant evidence for small-scale variations in the interstellar gas on scales less than or equal to 1 pc. To better understand the nature of small-scale variations in the ISM, we have used the KPNO WIYN Hydra multi-object spectrograph, which has a mapping advantage over the single-axis, single-scale limitations of studies using high proper motion stars and binary stars, to obtain moderate resolution (~12 km/s) interstellar Na I D absorption spectra of 172 stars toward the double open cluster h and Chi Persei. All of the sightlines toward the 150 stars with spectra that reveal absorption from the Perseus spiral arm show different interstellar Na I D absorption profiles in the Perseus arm gas. Additionally, we have utilized the KPNO Coude Feed spectrograph to obtain high-resolution (~3 km/s) interstellar Na I D absorption spectra of 24 of the brighter stars toward h and Chi Per. These spectra reveal an even greater complexity in the interstellar Na I D absorption in the Perseus arm gas and show individual components changing in number, velocity, and strength from sightline to sightline. If each of these individual velocity components represents an isolated cloud, then it would appear that the ISM of the Perseus arm gas consists of many small clouds. Although the absorption profiles vary even on the smallest scales probed by these high-resolution data (~30";~0.35pc), our analysis reveals that some interstellar Na I D absorption components from sightline to sightline are related, implying that the ISM toward h and Chi Per is probably comprised of sheets of gas in which we detect variations due to differences in the local physical conditions of the gas.Comment: 27 pages text; 8 figure

Implications of the Low Carbon Fuel Standard for State and National Ethanol Use

Resource /Energy Economics and Policy,

Exploring Methodologies to Improve Lignin Utilization in Biorefineries

The increasing world population, coupled with an improving quality of life, has driven a rapidly increasing demand for fuels, chemicals, and materials. Fossil carbon feedstocks, such as petroleum, are currently being consumed to meet these demands. The utilization of these feedstocks has negative impacts on human and environmental health, which are undoubtedly intensifying as a result of the increased reliance required to meet these demands. As an alternative way to meet these demands, biorefineries generate a wide range of fuels, chemicals, and materials from biomass, a renewable and sustainable resource. Current second-generation biorefineries use a plant-based feedstock, lignocellulosic biomass, comprised of three main components: cellulose, hemicellulose, and lignin. Second-generation biorefineries focus on converting cellulose and hemicellulose into fermentative fuels, discarding lignin as waste. Lignin is a complex and recalcitrant random co-polymer that is difficult to isolate and process, but it is comprised of molecular sub-unit structures that are analogous to many high value components of petroleum. If biorefineries are to compete against and mitigate the harmful effects of petroleum refineries, they must efficiently utilize all three major biomass components to increase product diversity, value, and yields. This dissertation explores extracting and upgrading lignin to improve its utilization in biorefineries. The first study investigates the use of a series of organic solvent mixtures to extract usable lignin from the waste stream of an ammonia fiber explosion extraction (AFEX) biorefinery. It focuses on understanding the solvent characteristics that control the lignin yield and resulting physochemical properties. An ethanol:water mixture effectively separates lignin from the waste, with high yields and only minor chemical modifications. By utilizing a current waste stream, the technology is easily adopted without disrupting the biorefinery operation. The dissertation next explores the reactions occurring during organosolv pretreatment that control the lignin extraction efficiency, as well as reactions associated with key physiochemical characteristics. A ‘pseudo-first order in series’ reaction model was applied to nuclear magnetic resonance (NMR) data of extracted lignin and kinetics constants for lignin yields and the chemical moieties related to important physicochemical properties were elicited. This study provides guiding principles for designing future organosolv processes that obtain lignin streams with desired qualities. In a final study, Fourier Transform Ion Cyclotron Resonance High Resolution Mass Spectrometry (FT-ICR HRMS) is used to analyze lignin breakdown products after catalytic upgrading. FT-ICR HRMS overcomes many problems other characterization methods face, but a single analysis results in thousands of data points, making processing the data difficult, thus a petroleomic analysis is adopted to easily track key characteristics. In the study, FT-ICR HRMS and a petroleomic analysis are applied to a catalysis and stabilizing co-solvent system that effectively fragments the lignin while preserving important chemical moieties, as shown by petroleomic analysis of the FT-ICR HRMS data. All three of the technologies explored within this dissertation offer avenues to improve the technical and economic viability of biorefinerie