Does solar structure vary with solar magnetic activity?

We present evidence that solar structure changes with changes in solar activity. We find that the adiabatic index, Gamma_1, changes near the second helium ionization, i.e., at a depth of about 0.98 R_sun. We believe that this change is a result of the change in the effective equation of state caused by magnetic fields. Inversions should be able to detect the changes in Gamma_1 if mode sets with reliable and precise high-degree modes are available.Comment: To appear in ApJ Letter

Mass problems and intuitionistic higher-order logic

In this paper we study a model of intuitionistic higher-order logic which we call \emph{the Muchnik topos}. The Muchnik topos may be defined briefly as the category of sheaves of sets over the topological space consisting of the Turing degrees, where the Turing cones form a base for the topology. We note that our Muchnik topos interpretation of intuitionistic mathematics is an extension of the well known Kolmogorov/Muchnik interpretation of intuitionistic propositional calculus via Muchnik degrees, i.e., mass problems under weak reducibility. We introduce a new sheaf representation of the intuitionistic real numbers, \emph{the Muchnik reals}, which are different from the Cauchy reals and the Dedekind reals. Within the Muchnik topos we obtain a \emph{choice principle} $(\forall x\,\exists y\,A(x,y))\Rightarrow\exists w\,\forall x\,A(x,wx)$ and a \emph{bounding principle} $(\forall x\,\exists y\,A(x,y))\Rightarrow\exists z\,\forall x\,\exists y\,(y\le_{\mathrm{T}}(x,z)\land A(x,y))$ where $x,y,z$ range over Muchnik reals, $w$ ranges over functions from Muchnik reals to Muchnik reals, and $A(x,y)$ is a formula not containing $w$ or $z$. For the convenience of the reader, we explain all of the essential background material on intuitionism, sheaf theory, intuitionistic higher-order logic, Turing degrees, mass problems, Muchnik degrees, and Kolmogorov's calculus of problems. We also provide an English translation of Muchnik's 1963 paper on Muchnik degrees.Comment: 44 page

What do we know (and not know) about potential output?

Potential output is an important concept in economics. Policymakers often use a one-sector neoclassical model to think about long-run growth, and they often assume that potential output is a smooth series in the short run -- approximated by a medium- or long-run estimate. But in both the short and the long run, the one-sector model falls short empirically, reflecting the importance of rapid technological change in producing investment goods; and few, if any, modern macroeconomic models would imply that, at business cycle frequencies, potential output is a smooth series. Discussing these points allows the authors to discuss a range of other issues that are less well understood and where further research could be valuable.Economic development ; Economic conditions

Superconducting Gap Nodal Surface and Fermi Surface: their partial overlap in cuprates

Electron correlation in cuprates leads to a global constraint $\sum_{\bf k} \Delta_{\bf k} = 0$ on the gap function $\Delta_{\bf k}$ resulting in a gap nodal surface. We give physical arguments supported by numerical results and discuss some experimental results to argue that correlations also lead to a local constraint on charge fluctuations in ${\bf k}$-space close to the Fermi surface, which may result in a substantial overlap of the Fermi surface with the gap nodal surface.Comment: RevTeX 3.0, 4 Pages, 6 PostScript Figures

Aggregate Productivity and the Productivity of Aggregates

Explanations of procyclical productivity play a key role in a variety of business-cycle models. Most of these models, however, explain this procyclicality within a representative-firm paradigm. This procedure is misleading. We decompose aggregate productivity changes into several terms, each of which has an economic interpretation. However, many of these terms measure composition effects such as reallocations of inputs across productive units. We apply this decomposition to U.S. data by aggregating from roughly the two-digit level to the private economy. We find that the compositional terms are significantly procyclical. Controlling for these terms virtually eliminates the evidence for increasing returns to scale, and implies that input growth is uncorrelated with technology change.

What do we know and not know about potential output?

Potential output is an important concept in economics. Policymakers often use a one-sector neoclassical model to think about long-run growth, and often assume that potential output is a smooth series in the short run--approximated by a medium- or long-run estimate. But in both the short and long run, the one-sector model falls short empirically, reflecting the importance of rapid technical change in producing investment goods; and few, if any, modern macroeconomic models would imply that, at business cycle frequencies, potential output is a smooth series. Discussing these points allows us to discuss a range of other issues that are less well understood, and where further research could be valuable.Input-output analysis ; Productivity ; Monetary policy

Impact of Grain Legume (Groundnut) on Energy and Nutritional Levels of Tribal Farm Households in Koraput (Orissa)

The introduction of groundnut through the support of IFAD & ICRISAT in the tribal areas of Koraput in Orissa has been able to supplement the nutritional levels of farm households in the area. The protein intake due to groundnut consumption has been found to be around 20 per cent in the IFAD participants and 11 per cent in the non-participants. The study has observed a perceptible contribution of groundnut (grain legume) in meeting the protein and energy needs of the tribal farm households in the study area. Further, groundnut has been found as the cheapest source of protein and energy among different food items like fish, meat, egg, etc., consumed by the tribal households. This low-cost energy-rich grain legume (groundnut) may be popularised to increase the frequency and quantity of intake to achieve nutritionally secured human resource (tribal people). This strategy will also enhance the sustainable crop production due to inherent advantage of legumes in the cropping system like soil health improvement, low external input addition, atmospheric nitrogen fixation by beneficial microorganisms and reduced soil and environmental pollution.Crop Production/Industries, Food Security and Poverty,