3,580 research outputs found

    DOES ECONOMIC VULNERABILITY DEPEND ON PLACE OF RESIDENCE? ASSET POVERTY ACROSS THE RURAL-URBAN CONTINUUM

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    This paper uses Panel Study of Income Dynamics data for 1989, 1994, and 1999 to examine why some U.S. households are asset poor; that is, why households have insufficient resources to invest in their future or to sustain household members at a basic level during times of economic disruption. The study contributes to an improved understanding of asset poverty's correlates by examining the influence of place of residence; the extant literature has focused on individual-level explanations. We estimate a random-effects logistic model of the probability that an individual is asset poor at a given point in time as a function of household-level (e.g. age, gender, race of the household head and family structure) and place-level (regional and rural-urban continuum) variables. The central finding of the paper is that place of residence is an important determinant of asset poverty, above and beyond the influence of household characteristics. We find that living in a central metropolitan county and in a nonmetropolitan area is associated with a higher risk of being asset poor, all else being equal. Implications for future research are discussed.Food Security and Poverty,

    One lumbar extension training session per week is sufficient for strength gains and reduction in pain in patients with chronic low back pain ergonomics

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    Chronic low back pain (CLBP) is the leading cause of absenteeism from the workplace and research into exercise interventions to address this problem is required. This study investigated training frequency for participants with CLBP. Participants either trained once a week (1 × week, n = 31), or twice a week (2 × week, n = 20) or did not (control group, n = 21). Participants were isometric strength tested in weeks 1 and 12 and trained dynamically either 1×week (80% of maximum) or 2×week (80% and 50%). The results (pre vs. post) showed significant increases in maximal strength, range of motion and reductions in pain for both training groups. Pain scores for the 1 × week and 2 × week both reached minimal clinical improvement change unlike the control group. Thus, one lumbar extension training session per week is sufficient for strength gains and reductions in pain in low back pain in CLBP patients

    Functional Tissue Engineering of the Healing Anterior Cruciate Ligament: A Combined Experimental and Computational Approach

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    The anterior cruciate ligament (ACL) is the most important knee stabilizer and is frequently injured during sports and work related activities. Unfortunately, midsubstance ACL ruptures have a limited healing capacity. As such, surgical reconstruction using soft tissue autografts is often performed. However, long-term follow-up studies have revealed that 20-25% of patients had a less than satisfactory outcome. These negative results have renewed clinical interests in healing of a torn ACL by means of biological stimulation. Thus, there is a need for basic science studies in order to better understand such an approach and also to logically develop an effective functional tissue engineering (FTE) treatment for an injured ACL. The overall objective of this dissertation was to evaluate the positive impact of biological and mechanical augmentation on the healing of the ACL using a combined experimental and computational approach. The ability of an extracellular matrix (ECM) bioscaffold in combination with an ECM hydrogel to enhance ACL healing following suture repair was first demonstrated in the goat model. At 12 weeks of healing, ECM-treatment led to an increase in neo-tissue formation as well as improved biomechanical properties of the healing ACL compared to suture repair alone. Second, as the healing process of the ACL was relatively slow even with ECM treatment, mechanical augmentation to better restore initial joint stability was required. Therefore, a suture augmentation procedure was developed, and improved joint function was achieved versus suture repair alone at the time of surgery. Further, there was increased tissue formation and improved biomechanical properties of the healing ACL at 12 weeks of healing. Finally, as a step toward predicting long-term outcomes following these biological and mechanical augmentation procedures, a preliminary mathematical model was developed to describe the remodeling process of healing ligaments. The results of this work can now be used to guide future experiments using FTE treatments to enhance ACL healing. With a sound scientific basis, it is hoped that such exciting new technologies could then be translated into the clinical arena to improve patient outcome following ACL injuries

    NAFTA: Testing Ricardo’s Theory of Comparative Advantage

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    Fluid Coexistence close to Criticality: Scaling Algorithms for Precise Simulation

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    A novel algorithm is presented that yields precise estimates of coexisting liquid and gas densities, ρ±(T)\rho^{\pm}(T), from grand canonical Monte Carlo simulations of model fluids near criticality. The algorithm utilizes data for the isothermal minima of the moment ratio QL(T;L)Q_{L}(T;_{L}) <m2>L2/L\equiv< m^{2}>_{L}^{2}/_{L} in LL× \times... ...× \timesL L boxes, where m=ρLm=\rho-_{L}. When LL \to \infty the minima, Qm±(T;L)Q_{\scriptsize m}^{\pm}(T;L), tend to zero while their locations, ρm±(T;L)\rho_{\scriptsize m}^{\pm}(T;L), approach ρ+(T)\rho^{+}(T) and ρ(T)\rho^{-}(T). Finite-size scaling relates the ratio {\boldmath Y\mathcal Y}= = (ρm+ρm)/Δρ(T)(\rho_{\scriptsize m}^{+}-\rho_{\scriptsize m}^{-})/\Delta\rho_{\infty}(T) {\em universally} to 1/2(Qm++Qm){1/2}(Q_{\scriptsize m}^{+}+Q_{\scriptsize m}^{-}), where Δρ\Delta\rho_{\infty}= = ρ+(T)ρ(T)\rho^{+}(T)-\rho^{-}(T) is the desired width of the coexistence curve. Utilizing the exact limiting (L(L \to )\infty) form, the corresponding scaling function can be generated in recursive steps by fitting overlapping data for three or more box sizes, L1L_{1}, L2L_{2}, ......, LnL_{n}. Starting at a T0T_{0} sufficiently far below TcT_{\scriptsize c} and suitably choosing intervals ΔTj\Delta T_{j}= = Tj+1TjT_{j+1}-T_{j}> > 0 yields Δρ(Tj)\Delta\rho_{\infty}(T_{j}) and precisely locates TcT_{\scriptsize c}
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