Duality of the Weak Parallelogram Laws on Banach Spaces

This paper explores a family of weak parallelogram laws for Banach spaces. Some basic properties of such spaces are obtained. The main result is that a Banach space satisfies a lower weak parallelogram law if and only if its dual satisfies an upper weak parallelogram law, and vice versa. Connections are established between the weak parallelogram laws and the following: subspaces, quotient spaces, Cartesian products, and the Rademacher type and co-type properties

Off-farm Income and Investments in Farm Assets: A Double Hurdle Approach

The farm household structure is a complex set of inter-relationships between and among a variety of internal and external factors involving consumption, investment, and income-earning activities. In this paper we use ARMS data to explore the contribution of off-farm income to the viability of the farm business. We focus on the link between off-farm income and farm investment and whether off-farm income drives on-farm investment. The results indicate the importance of farm characteristics such as type, size, and location on the probability of investment but lead us to reject the hypothesis that off farm income is driving farm investment. Further research will be needed to further unweave some of the complex relationships involved in the farm household structure. Keywords: Farm investments, off-farm income, double hurdleOff-farm income, farm investment, double hurdle, Agricultural Finance, Financial Economics, D1, J2, Q12,

Uniform l1 Behavior of a Time Discretization Method for a Volterra Integrodifferential Equation With Convex Kernel; Stability

We study stability of a numerical method in which the backward Euler method is combined with order one convolution quadrature for approximating the integral term of the linear Volterra integrodifferential equation u\u27(t) + ∫0 β (t - s)Au(s) ds = 0, t ≥ 0, u(0) = u0, which arises in the theory of linear viscoelasticity. Here A is a positive self-adjoint densely defined linear operator in a real Hilbert space, and β (t) is locally integrable, nonnegative, nonincreasing, convex, and -β\u27(t) is convex. We establish stability of the method under these hypotheses on β(t). Thus, the method is stable for a wider class of kernel functions β(t) than was previously known. We also extend the class of operators A for which the method is stable. © 2011 Society for Industrial and Applied Mathematics

STEM Education in Rural Schools: Implications of Untapped Potential

A large number of students in American public schools attend rural schools. In this paper, the authors explore rural science, technology, engineering, and math (STEM) education and the issues associated with STEM education for students, teachers, and parents in rural communities. Characteristics of rural STEM education are examined to highlight unique considerations for this context. The authors conclude with the recommendation that more research is needed that specifically addresses rural STEM education

Determinants of Farm Household Income Diversification in the United States: Evidence from Farm-Level Data

This study examines the determinants of income diversification of farm households in the United States. Farm households allocate their time between farm and off-farm activities to help stabilized household income (consumption). What characterizes those households who engage in off-farm activities? Is there any pattern over time? Using 1999, 2003 and 2007 farm-level data from the USDA’s Agricultural Resource Management Survey (ARMS), this study estimates intensity of off-farm income (or income diversification). The results show that older operators, full owners, and small farms have higher intensity of off-farm income in total household income. In contrast, dairy farms, vertically coordinated farms and farms located in the Southern and Pacific regions have lower intensity of off-farm income. In other words, household incomes of these farms are less likely to be diversified.Tobit, income diversification, vertical integration, tenure, farm households, Agricultural Finance, Consumer/Household Economics, D1, J2, Q12,

Mapping the phase diagram of the writhe of DNA nanocircles using atomistic molecular dynamics simulations

We have investigated the effects of duplex length, sequence, salt concentration and superhelical density on the conformation of DNA nanocircles containing up to 178 base pairs using atomistic molecular dynamics simulation. These calculations reveal that the partitioning of twist and writhe is governed by a delicate balance of competing energetic terms. We have identified conditions which favour circular, positively or negatively writhed and denatured DNA conformations. Our simulations show that AT-rich DNA is more prone to denaturation when subjected to torsional stress than the corresponding GC containing circles. In contrast to the behaviour expected for a simple elastic rod, there is a distinct asymmetry in the behaviour of over and under-wound DNA nanocircles. The most biologically relevant negatively writhed state is more elusive than the corresponding positively writhed conformation, and is only observed for larger circles under conditions of high electrostatic screening. The simulation results have been summarised by plotting a phase diagram describing the various conformational states of nanocircles over the range of circle sizes and experimental conditions explored during the study. The changes in DNA structure that accompany supercoiling suggest a number of mechanisms whereby changes in DNA topology in vivo might be used to influence gene expression

Rating the Financial Health of U.S. Production Agriculture using Synthetic Credit Rating

Agribusiness, Agricultural and Food Policy, Production Economics,

Surgical intervention is not required for all patients with subclavian vein thrombosis

AbstractPurpose: The role of thoracic outlet decompression in the treatment of primary axillary-subclavian vein thrombosis remains controversial. The timing and indications for surgery are not well defined, and thoracic outlet procedures may be associated with infrequent, but significant, morbidity. We examined the outcomes of patients treated with or without surgery after the results of initial thrombolytic therapy and a short period of outpatient anticoagulation. Methods: Patients suspected of having a primary deep venous thrombosis underwent an urgent color-flow venous duplex ultrasound scan, followed by a venogram and catheter-directed thrombolysis. They were then converted from heparin to outpatient warfarin. Patients who remained asymptomatic received anticoagulants for 3 months. Patients who, at 4 weeks, had persistent symptoms of venous hypertension and positional obstruction of the subclavian vein, venous collaterals, or both demonstrated by means of venogram underwent thoracic outlet decompression and postoperative anticoagulation for 1 month. Results: Twenty-two patients were treated between June 1996 and June 1999. Of the 18 patients who received catheter-directed thrombolysis, complete patency was achieved in eight patients (44%), and partial patency was achieved in the remaining 10 patients (56%). Nine of 22 patients (41%) did not require surgery, and the remaining 13 patients underwent thoracic outlet decompression through a supraclavicular approach with scalenectomy, first-rib resection, and venolysis. Recurrent thrombosis developed in only one patient during the immediate period of anticoagulation. Eleven of 13 patients (85%) treated with surgery and eight of nine patients (89%) treated without surgery sustained durable relief of their symptoms and a return to their baseline level of physical activity. All patients who underwent surgery maintained their venous patency on follow-up duplex scanning imaging. Conclusion: Not all patients with primary axillary-subclavian vein thrombosis require surgical intervention. A period of observation while patients are receiving oral anticoagulation for at least 1 month allows the selection of patients who will do well with nonoperative therapy. Patients with persistent symptoms and venous obstruction should be offered thoracic outlet decompression. Chronic anticoagulation is not required in these patients. (J Vasc Surg 2000;32:57-67.

Faculty-Librarian Collaboration in Building the Curriculum for the Millennium: The US Experience

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68104/2/10.1177_034003529902500402.pd

Determining Transition State Geometries in Liquids Using 2D-IR

Many properties of chemical reactions are determined by the transition state connecting reactant and product, yet it is difficult to directly obtain any information about these short-lived structures in liquids. We show that two-dimensional infrared (2D-IR) spectroscopy can provide direct information about transition states by tracking the transformation of vibrational modes as a molecule crossed a transition state. We successfully monitored a simple chemical reaction, the fluxional rearrangement of Fe(CO)5, in which the exchange of axial and equatorial CO ligands causes an exchange of vibrational energy between the normal modes of the molecule. This energy transfer provides direct evidence regarding the time scale, transition state, and mechanism of the reaction