The Harmonic Oscillator, a Review of Classical and Elementary Quantum Mechanics

The classical harmonic oscillator and an elementary discussion of the quantum mechanical solutions for the harmonic oscillator are discussed.

Intrinsic characteristics of the proton pump in the luminal membrane of a tight urinary epithelium. The relation between transport rate and delta mu H.

A number of tight urinary epithelia, as exemplified by the turtle bladder, acidify the luminal solution by active transport of H+ across the luminal cell membrane. The rate of active H+ transport (JH) decreases as the electrochemical potential difference for H+ [delta mu H = mu H(lumen) - mu H(serosa)] across the epithelium is increased. The luminal cell membrane has a low permeability for H+ equivalents and a high electrical resistance compared with the basolateral cell membrane. Changes in JH thus reflect changes in active H+ transport across the luminal membrane. To examine the control of JH by delta mu H in the turtle bladder, transepithelial electrical potential differences (delta psi) were imposed at constant acid-base conditions or the luminal pH was varied at delta psi = 0 and constant serosal PCO2 and pH. When the luminal compartment was acidified from pH 7 to 4 or was made electrically positive, JH decreased as a linear function of delta mu H as previously described. When the luminal compartment was made alkaline from pH 7 to 9 or was made electrically negative, JH reached a maximal value, which was the same whether the delta mu H was imposed as a delta pH or a delta psi. The nonlinear JH vs. delta mu H relation does not result from changes in the number of pumps in the luminal membrane or from changes in the intracellular pH, but is a characteristic of the H+ pumps themselves. We propose a general scheme, which, because of its structural features, can account for the nonlinearity of the JH vs. delta mu H relations and, more specifically, for the kinetic equivalence of the effects of the chemical and electrical components of delta mu H. According to this model, the pump complex consists of two components: a catalytic unit at the cytoplasmic side of the luminal membrane, which mediates the ATP-driven H+ translocation, and a transmembrane channel, which mediates the transfer of H+ from the catalytic unit to the luminal solution. These two components may be linked through a buffer compartment for H+ (an antechamber).

The Association Between Triglyceride and Leptin Levels in Obese Subjects Following a Low-Carbohydrate or Low-Fat Diet

Obesity has been cited as the second leading preventable cause of death in the United States. Studies have determined that at risk overweight and obese individuals have high circulating levels of leptin indicative of leptin resistance as well as elevated levels of plasma triglycerides. Postulates have been formed that link elevated levels of triglycerides with the inhibition of leptin across the blood-brain barrier. If a method of lowering triglycerides is achieved, leptin should be able to cross the blood-brain barrier and reach the ypothalamus, thus regulating body weight through a decrease in appetite and increase in energy expenditure. The primary aim of this study was to compare the effects of both carbohydrate and fat restricted diets on plasma triglycerides and leptin concentrations in overweight and obese subjects with hypertriglyceridemia. Forty subjects were randomly assigned to either the low carbohydrate or low fat diet group for a 12 wk period. Plasma triglyceride and leptin concentrations in the blood were analyzed before and after the 12 wk period to assess diet-induced changes. Both groups had a significant reduction in body weight, though the effect was much greater in the carbohydrate restricted diet group. Fasting and postprandial plasma triglycerides also decreased to a greater extent in the low carbohydrate diet group. Similarly, leptin levels decreased to a greater extent in the carbohydrate restricted diet group. The changes in leptin levels were directly related to the changes in both fasting and postprandial triglyceride levels. The results from this study provide preliminary evidence of diet-induced triglyceride reductions as an underlying mechanism in lowering plasma leptin and improving leptin sensitivity. Further, they provide evidence that an increase in triglyceride levels is at least partially responsible for leptin resistance and reduced leptin sensitivity in obese hypertriglyceridemic individuals. This novel discovery is important as it raises the possibility that other methods of lowering triglycerides may improve the efficiency of leptin transport and ultimately improve fat metabolism in overweight and obese individuals.

Factors Related to Mental Health of Native Americans in Eastern Tribes

This paper is part of a five-year research project funded by the National Institute on Disability and Rehabilitation Research (NIDRR) that addresses the health, disability and service needs of Native Americans in eastern tribes. The Participatory Action Research model with a community-based approach was used to facilitate collaboration among the participating tribes. Native American research technicians conducted individual interviews with members of their tribes. Demographics, prevalence of disabilities, and various factors associated with health and mental health are presented. Of the 858 tribal members who responded to survey questions, the third most prominent health problem reported was mental illness.

Automatic Stabilizer Feature of Fixed Exchange Rate Regimes in Emerging Markets

This paper shows that countries characterized by a financial accelerator mechanism may reverse the usual finding of the literature -- flexible exchange rate regimes do a worse job of insulating open economies from external shocks. I obtain this result with a calibrated small open economy model that endogenizes foreign interest rates by linking them to the banking sector's foreign currency leverage. This relationship renders exchange rate policy more important compared to the usual exogeneity assumption. I find empirical support for this prediction using the Local Projections method. Finally, 2nd order approximation to the model finds larger welfare losses under flexible regimes.

Digital repository implementation: a toolbox for streamlined success

Purpose – The purpose of this paper is to describe the tools and strategies that were employed by C/W MARS to successfully develop and implement the Digital Treasures digital repository. Design/methodology/approach – This paper outlines the planning and subsequent technical issues that arise when implementing a digitization project on the scale of the large, multi-type, automated library network. Workflow solutions addressed include synchronous online metadata record submissions from multiple library sources and the delivery of collection-level use statistics to participating library administrators. The importance of standards-based descriptive metadata and the role of project collaboration are also discussed. Findings – From the time of its initial planning, the Digital Treasures repository was fully implemented in six months. The discernable and statistically quantified online discovery and access of actual digital objects greatly assisted libraries unsure of their own staffing costs/benefits to join the repository. Originality/value – This case study may serve as a possible example of initial planning, workflow and final implementation strategies for new repositories in both the general and library consortium environment. Keywords – Digital repositories, Library networks, Data management. Paper type – Case study