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Second-generation or lignocellulosic biofuels are a tangible source of renewable energy, which is critical to combat climate change by reducing the carbon footprint. Filamentous fungi secrete cellulose-degrading enzymes called cellulases, which are used for production of lignocellulosic biofuels. However, inefficient production of cellulases is a major obstacle for industrial-scale production of second-generation biofuels. We used computational simulations to design and implement synthetic positive feedback loops to increase gene expression of a key transcription factor, CLR-2, that activates a large number of cellulases in a filamentous fungus, Neurospora crassa. Overexpression of CLR-2 reveals previously unappreciated roles of CLR-2 in lignocellulosic gene network, which enabled simultaneous induction of approximately 50% of 78 lignocellulosic degradation-related genes in our engineered Neurospora strains. This engineering results in dramatically increased cellulase activity due to cooperative orchestration of multiple enzymes involved in the cellulose degradation pathway. Our work provides a proof of principle in utilizing mathematical modeling and synthetic biology to improve the efficiency of cellulase synthesis for second-generation biofuel production.

The underlying theory behind child support guidelines implies that child support orders should change when the incomes of noncustodial parents change. This paper documents changes in noncustodial fathers' earnings over a five-year period and examines the relationship between the changes in earnings and modifications in child support orders. Using detailed longitudinal administrative data from Wisconsin, the authors examine the history of orders and earnings for fathers in couples who had their first child support ordered in 2000. A substantial proportion of fathers experience large changes in earnings, but relatively few of the associated child support orders are modified. Using discrete-time multinomial event history models that consider time-varying variables and control for censored observations, we find some evidence of changes in earnings being associated with changes in orders, all else equal, but the relationship is relatively weak and order changes are not proportional to earnings changes. The findings highlight the challenges and importance of developing policies that result in child support orders being more responsive to changes in fathers' incomes. (Contains 2 figures, 3 tables and 11 footnotes.)

In most states, child support paid on behalf of Temporary Assistance for Needy Families (TANF) participants is used to offset TANF and child support administrative expenditures; this policy primarily benefits taxpayers. In contrast, Wisconsin allowed most custodial parents to keep all support paid on their behalf. This policy, which treats welfare and child support as complements, was evaluated through an experimental design. This paper reports the key results of the experimental evaluation, using state administrative data to examine the effects on child support outcomes and governmental cost. We find that when custodial mothers keep all child support paid on their behalf, paternity establishment occurs more quickly, noncustodial fathers are more likely to pay support, and custodial families receive more support. These outcomes are achieved at no significant governmental cost. (Contains 5 tables and 32 footnotes.)

This study identified the employment and earnings trajectories of welfare recipients over six years for a sample of 14,150 women who entered the Temporary Assistance for Needy Families program (TANF) in Wisconsin in its first year. Wisconsin longitudinal administrative data were used to examine differential patterns of mid-term (three years) and long-term (six years) employment and earnings success. We developed a conceptual approach to categorizing participants' employment and earnings trajectory groups. Results indicate substantial diversity in employment and earnings patterns. Some women have consistently positive outcomes, others show steady improvements over time, and others have inconsistent patterns that end strong. We found that 46% of the sample fit into one of three successful employment trajectories, and 22% fit into one of three successful earnings trajectories. Results also reveal that many women who were successful in the mid-term were not able to sustain their progress. For example, only 56% of those who were earning successes in the mid-term were still successful in the long-term. Finally, logistic regression models were used to compare the factors associated with mid-term and long-term success and with employment success and earnings success. Implications of findings are discussed.

There is little research on knowledge of the policy rules that could affect individuals, either in general or in evaluations of new programs. The lack of research is surprising, given that knowledge gaps could limit the effectiveness of reforms or lead to incorrect inferences regarding the effects of a policy change. In this article, we use survey data to examine the level and sources of welfare participants' policy knowledge in the context of a substantial change in child support and welfare policy in Wisconsin. We find very low levels of knowledge of child support policy rules. Multivariate analyses suggest that people tend to learn policy rules by experience; we find less consistent support for knowledge being primarily imparted through interactions with caseworkers. A difference-in-difference analysis suggests that if participants had been more knowledgeable, program impacts would have been larger. Implications of this research for policy implementation and policy evaluations are discussed. (Contains 4 tables and 18 footnotes.)

Under Temporary Assistance for Needy Families, families are subject to greater work requirements, and the severity of sanction for noncompliance has increased. Using Wisconsin longitudinal administrative data, the authors performed event history analysis to examine the dynamic patterns of sanctioning and the patterns of benefits following a sanction. They found that very high rates of sanctioning (especially partial sanctions) and multiple sanctions were fairly common but sanction spells were quite short. The most common transition from a sanction was back to full benefit receipt. The authors also examined the factors associated with being sanctioned and the severity of sanctions by comparing a traditional model with an event history model. They found that it is important to estimate a model that takes into account the period of risk. Results confirm that those who may be least able to succeed in the labor market are most likely to be sanctioned.

Welfare programs changed dramatically in 1996. Caseloads dropped by more than 9 million recipients over an eight-year period, and millions entered the labor market in the wake of these changes. Since the start of the "welfare revolution," research has emerged to document the new ways former welfare recipients are using federal entitlement programs as they navigate and negotiate the "post-AFDC" era. In this article, the authors examine patterns of participation in TANF, the Food Stamp program, and Medicaid in Wisconsin. Very distinct patterns of participation emerged among the three programs: a single short period of receipt was common for TANF cycling was typical for food stamps, and a long spell was the standard for Medicaid. The authors also explored multiple program participation over a three-year period. Analysis revealed interactions and transitions not normally considered in this line of research. One key finding was the high number of transitions on and off benefits during these three years when the three programs were considered simultaneously. Policy implications are discussed.

Current debates about the success of TANF reforms have been obscured by the use of inconsistent indicators of success, as well as by measurement difficulties associated with alternative indicators. This paper considers conceptual and measurement issues associated with three different indicators of economic well-being: independence from public assistance, having income above the poverty threshold, and freedom from material hardship. Survey and administrative data from a sample of TANF participants illustrate the sensitivity of conclusions to alternative ways of measuring each indicator. Also considered is the extent to which dependence, poverty, and hardship coincide, or capture important differences in outcomes. The principles underlying TANF reforms have implications for appropriate measures of economic well-being, as the empirical importance of these implications demonstrates.

Uses data from National Longitudinal Survey of Youth to trace poverty status and welfare use in five years following an exit from Aid to Families with Dependent Children (AFDC). Results show substantial diversity in economic well-being. Women who were working when they exited from AFDC do better, and, to a lesser extent so do those who were married or had a partner when they exited. (Author/MKA)

Examines five-year compliance patterns among Wisconsin child support cases that came to court in 1986 to 1998. Compliance during the first year provides some indication of long-term compliance, but half of fathers change their compliance rate over the period. Differences between divorced and unmarried fathers are discussed. (Author/MKA)

Examines compliance with child support orders by divorced fathers in Wisconsin during 1981-89. The fathers' ability to pay is strongly related to compliance: compliance increases as the fathers' income increases. Analysis of nonpaying fathers suggests that although they are not a high-income group, they are generally not so poor that they could not afford to pay at least some support. (KW)

Reviews implementation and effects of three child support reforms in Wisconsin to determine the child support policies that yield the greatest benefit to dependent children. Expressing child support orders as a percentage of noncustodial parent's income increases amount of orders and payments. Withholding payment from noncustodial parents' income increases support payments. (SNR)

Examines Wisconsin divorce cases (n=3,774) before and after income-sharing guidelines were implemented relating to child support. Found that the negative impact of the mother's income on the size of child support orders has fallen substantially since the guidelines have been effective. Discusses implications. (RB)

Examined three data sets to explore assumptions about custodial fathers: there are few father-only families, most custodial fathers have remarried, many single fathers are widowers, custodial fathers have high incomes, and fathers primarily receive custody of older boys. Concluded that many assumptions are untrue and that child support policies should follow same principles regardless of who has custody. (Author/NB)