Universality Class of One-Dimensional Directed Sandpile Models

A general n-state directed `sandpile' model is introduced. The stationary properties of the n-state model are derived for n < infty, and analytical arguments based on a central limit theorem show that the model belongs to the universality class of the totally asymmetric Oslo model, with a crossover to uncorrelated branching process behavior for small system sizes. Hence, the central limit theorem allows us to identify the existence of a large universality class of one-dimensional directed sandpile models.Comment: 4 pages, 2 figure

Relative Labor Productivity and the Real Exchange Rate in the Long Run: Evidence for a Panel of OECD Countries

The Balassa-Samuelson model, which explains real exchange rate movements in terms of sectoral productivities, rests on two components. First, for a class of technologies including Cobb-Douglas, the model implies that the relative price of nontraded goods in each country should reflect the relative productivity of labor in the traded and nontraded goods sectors. Second, the model assumes that purchasing power parity holds for traded goods in the long-run. We test each of these implications using data from a panel of OECD countries. Our results suggest that the first of these two fits the data quite well. In the long run, relative prices generally reflect relative labor productivities. The evidence on purchasing power parity in traded goods is considerably less favorable. When we look at US dollar exchange rates, PPP does not appear to hold for traded goods, even in the long run. On the other hand, when we look at DM exchange rates purchasing power parity appears to be a somewhat better characterization of traded goods prices.

How Do Monetary and Fiscal Policy Interact in the European Monetary Union?

Formation of the Euro area raises new questions about the coordination of monetary and fiscal policy. Using a New Neoclassical Synthesis (NNS) model, we show that a common monetary policy, responding to area-wide aggregates, has asymmetric effects on countries within the union, depending on whether they are large or small, or whether they have high or low debts. We analyze the implications of these asymmetries for the various countries welfare and for their fiscal policies. We also study rules for setting national tax and spending rates, rules that constrain movements in the deficit to GDP ratio. We ask whether these rules are necessary for the common monetary policy to be able to harmonize national inflation rates, and we analyze their effects on national welfare. We also discuss some potential failings of our model (and perhaps NNS models generally); in particular, our model's variance decompositions suggest that productivity shocks may play an inordinately large role, while fiscal shocks (or demand shocks generally) may play too small a role (even when 'rule of thumb' spenders are added).

Price- and wage- inflation targeting: variations on a theme by Erceg, Henderson, and Levin

Inflation (Finance) ; Prices ; Wages

The Need for International Policy Coordination: What's Old, What's New, What's Yet to Come?

Fifty years ago, the Chicago School argued that flexible exchange rates would insulate employment from foreign economic disturbances: there is no need for policy coordination; flexible exchange rates suffice. Twenty five years later, the Bretton Woods system was gone, and the first generation of policy coordination models was introduced. Chicago School arguments not withstanding, these Old-Keynesian models provided a theoretical rational for policy coordination. Now, a new generation of policy coordination models is emerging. These New-Keynesian models incorporate optimizing households, monopolistic competition and nominal inertia. Here, we examine macroeconomic interdependence and the scope for policy coordination in a tractable second generation model that has received much recent attention. We relate our discussion to the old Chicago School arguments, to earlier analyses of first generation models, to recent empirical work on productivity, and to recent theoretical work on closed economy models. We conclude that second generation models may have more scope for policy coordination than did the first, and we identify the empirical work that is needed to give a serious answer to the question.

THE ROLE OF DIAPHRAGMATIC BREATHING IN SELF-REGULATION SKILLS TRAINING

A central component of many psychological interventions is breathing training. Breathing training protocols based on a mindfulness or a cognitive behavioral therapy (CBT) have demonstrated value in the management of psychological and medical ailments. Yet, despite the wealth of literature examining each approach, little direct comparison exists. An additional concern is the proliferation of smart phone health (mHealth) applications (apps) providing breathing training with little empirical evidence to support their clinical use. A possible explanation for the interest in breathing and mHealth apps is the growing body of literature indicating breathing training provides wide ranging health benefits through improved stasis of the autonomic nervous system (ANS). As ANS dysregulation underlies many chronic health conditions such as persistent temporomandibular disorders (TMDs), there is a need for empirical research to identify the most effective modality of breathing training and validate the clinical efficacy of breathing based mHealth apps. Study One compared the effectiveness of a mindfulness breathing meditation (MB) and a CBT based protocol teaching diaphragmatic breathing (DB) to improve biomarkers of ANS stasis. An attention control approach based on the Nolen-Hoeksema task (C) was included as a comparison group. Ninety participants were randomly assigned to either the MB, DB, or C condition. Within each condition, 30 participants were provided skills training with practice time and completed a behavioral self-regulation task. Participants in the DB condition approach had significantly lower breathing rates than those in the MB and C conditions (p \u3c .001). DB condition participants experienced improvements on high-frequency heart rate variability (p \u3c .05) and the standard deviation in NN intervals (p \u3c .001), which served as indicators for ANS stasis. No differences were found between conditions on the behavioral self-regulation task (p’s \u3e .05). Given these results, the DB training protocol was converted into a mHealth app to facilitate a clinical trial with patients suffering persistent TMDs. Study Two examined the additive benefits of including the mHealth app with standard dental care (SDC+) versus standard dental care alone (SDC). Nineteen patients seeking care for persistent TMDs were recruited. All participants were asked to track daily ratings of pain (VAS), relaxation (RR), and complete weekly assessments on several comorbid psycho-social factors. Within the SDC+ condition participants were asked to track the proximate effects of each breathing practice on VAS and RR ratings. Given a high drop-out rate (nine participants) and low overall sample size (N = 10), results are exploratory at best. Within the SDC+ condition, results indicated reliable improvements in average VAS and RR ratings from before and after SDC+ participants used the mHealth app (p’s \u3c .05). Within a one session training paradigm, results supported the use of a DB based intervention above the use of a MB or C intervention. Future research should consider the effects of having multiple training sessions. Study Two results were complicated by a limited sample size and failed to provide a clear picture of whether the conjunctive treatment in the SDC+ condition provided additional symptom relief above traditional dental care alone. Although exploratory results indicated the mHealth app provided temporary improvements in pain and feelings of relaxation, a well powered trial is needed to clarify whether the finding represents an enduring treatment effect