Small Towns and Welfare Reform: Iowa Case Studies of Families and Communities

Since passage of the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) in 1996, public discussion of welfare reform and most research efforts to assess the effects of new policies have focused on urban areas. Major studies and frequent newspaper headlines have portrayed the dimensions of welfare reform in Los Angeles, Miami, Boston, and other urban settings (e.g., Burton et al. 1998; Quint et al. 1999). Little attention is being paid to the consequences of the new policies for rural families and communities.This book chapter is published as 2002 Fletcher, C. N., Flora, J. L., Gaddis, B. J., Winter, M., and J. S. Litt. “Small Towns and Welfare Reform: Iowa Case Studies of Families and Communities.” In Bruce A. Weber, Greg J. Duncan and Leslie A. Whitener (eds.) Rural Dimensions of Welfare Reform: Welfare, Food Assistance and Poverty in Rural America (pp. 201-229). Kalamazoo, MI: Upjohn Press. 10.17848/9781417508884 </p

Sensory imagery in craving: From cognitive psychology to new treatments for addiction

Sensory imagery is a powerful tool for inducing craving because it is a key component of the cognitive system that underpins human motivation. The role of sensory imagery in motivation is explained by Elaborated Intrusion (EI) theory. Imagery plays an important role in motivation because it conveys the emotional qualities of the desired event, mimicking anticipated pleasure or relief, and continual elaboration of the imagery ensures that the target stays in mind. We argue that craving is a conscious state, intervening between unconscious triggers and consumption, and summarise evidence that interfering with sensory imagery can weaken cravings. We argue that treatments for addiction can be enhanced by the application of EI theory to maintain motivation, and assist in the management of craving in high-risk situations

Propulsion in a viscoelastic fluid

Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of respiratory airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid with a single relaxation time. We show that, compared to self-propulsion in a Newtonian fluid occurring at a velocity U_N, the sheet swims (or transports fluid) with velocity U / U_N = [1+De^2 (eta_s)/(eta) ]/[1+De^2], where eta_s is the viscosity of the Newtonian solvent, eta is the zero-shear-rate viscosity of the polymeric fluid, and De is the Deborah number for the wave motion, product of the wave frequency by the fluid relaxation time. Similar expressions are derived for the rate of work of the sheet and the mechanical efficiency of the motion. These results are shown to be independent of the particular nonlinear constitutive equations chosen for the fluid, and are valid for both waves of tangential and normal motion. The generalization to more than one relaxation time is also provided. In stark contrast with the Newtonian case, these calculations suggest that transport and locomotion in a non-Newtonian fluid can be conveniently tuned without having to modify the waving gait of the sheet but instead by passively modulating the material properties of the liquid.Comment: 21 pages, 1 figur

Simulation Study of Sulfonate Cluster Swelling in Ionomers

We have performed simulations to study how increasing humidity affects the structure of Nafion-like ionomers under conditions of low sulfonate concentration and low humidity. At the onset of membrane hydration, the clusters split into smaller parts. These subsequently swell, but then maintain constant the number of sulfonates per cluster. We find that the distribution of water in low-sulfonate membranes depends strongly on the sulfonate concentration. For a relatively low sulfonate concentration, nearly all the side-chain terminal groups are within cluster formations, and the average water loading per cluster matches the water content of membrane. However, for a relatively higher sulfonate concentration the water-to-sulfonate ratio becomes non-uniform. The clusters become wetter, while the inter-cluster bridges become drier. We note the formation of unusual shells of water-rich material that surround the sulfonate clusters.Comment: 24 pages, 15 figure

Local Wellness Policy 5 Years Later: Is It Making a Difference for Students in Low-Income, Rural Colorado Elementary Schools?

IntroductionThe federally mandated Local Wellness Policy (LWP) was intended to promote student health in schools. This study assesses the 5-year effects of the LWP on the health practices of rural elementary schools in Colorado. MethodsOne year before and 5 years after the LWP mandate, a survey was administered to a random sample of principals, physical education (PE) teachers, and food-service managers in 45 rural, low-income elementary schools in Colorado. Response rates were 71% in 2005 and 89% in 2011. ResultsMinutes for PE and recess did not increase, nor did offerings of fresh fruits and vegetables. More schools adopted policies prohibiting teachers from taking recess away as punishment (9.7% in 2005 vs 38.5% in 2011, P = .02) or for making up missed instructional time, class work, or tests in other subjects (3.2% in 2005 vs 28.2% in 2011, P = .03). More schools scheduled recess before lunch (22.6% in 2005 vs 46.2% in 2011, P = .04) and developed policies for vending machines (42.9% in 2005 vs 85.7% in 2011, P = .01) and parties (21.4% in 2005 vs 57.9% in 2011, P = .004). ConclusionChanges in school practices are modest, and arguably the important school practices such as increased PE and recess time and increased offerings of fruits and vegetables in the lunch line have not changed in the 5 years since the mandate went into effect. Further investigation is needed to identify the knowledge, skills, and attitudes as well as financial and physical resources required for school administrators to make changes in school practices

Arginine-rich peptides destabilize the plasma membrane, consistent with a pore formation translocation mechanism of cell-penetrating peptides

Recent molecular-dynamics simulations have suggested that the arginine-rich HIV Tat peptides translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, Arg residues play a fundamental role not only in the binding of the peptide to the surface of the membrane, but also in the destabilization and nucleation of transient pores across the bilayer. Here we present a molecular-dynamics simulation of a peptide composed of nine Args (Arg-9) that shows that this peptide follows the same translocation pathway previously found for the Tat peptide. We test experimentally the hypothesis that transient pores open by measuring ionic currents across phospholipid bilayers and cell membranes through the pores induced by Arg-9 peptides. We find that Arg-9 peptides, in the presence of an electrostatic potential gradient, induce ionic currents across planar phospholipid bilayers, as well as in cultured osteosarcoma cells and human smooth muscle cells. Our results suggest that the mechanism of action of Arg-9 peptides involves the creation of transient pores in lipid bilayers and cell membranes.Facultad de Ciencias Exacta