The Contribution of Sectoral Productivity Differentials to Inflation in Greee

This paper estimates the magnitude of the Balassa-Samuelson effect for Greece. We calculate the effect directly, using sectoral national accounts data, which permits estimation of total factor productivity (TFP) growth in the tradeables and nontradeables sectors. Our results suggest that it is difficult to produce one estimate of the BS effect. Any particular estimate is contingent on the definition of the tradeables sector and the assumptions made about labour shares. Moreover, there is also evidence that the effect has been declining through time as Greek standards of living have caught up on those in the rest of the world and as the non-tradeables sector within Greece catches up with the tradeables.Balassa-Samuelson effect, inflation, productivity

Some results on contractive mappings as related to pattern recognition

Several of the techniques used in pattern recognition are reformulated as the problem of determining fixed points of a function. If x sub 0 is a fixed point of f and if f is contractive at x sub 0, then, for any y belonging to a sufficiently small neighborhood of x sub 0 the orbit of y will converge to x sub 0. Several general results regarding contractive mappings are developed with emphasis on functions

The Collapse of Bell Determinism

The Bell-Kochen-Specker conditions (BKS) for a deterministic noncontextual hidden-variable model are wonderfully simple to state, deal with just one-dimensional projectors on a Hilbert space H and make no reference to a probabilistic phase space or quantum system. They only ask for an assignment of zero or one to every projector such that the assignment respects orthogonal resolutions of the identity. Various no-go results in the literature show that the pair of statements {BKS is valid; dim H greater than or equal to 3} are inconsistent. Here we show, more radically, that the pair actually contradicts the dimensionality of the space itself, by implying that there can exist at most a single one-dimensional projector acting on H. Our derivation involves only elementary inner product spaces. It is non-probabilistic, inequality-free, state independent, does not use entanglement, and is simultaneously valid in all dimensions three or greater.Comment: accepted for publication in Physics Letters A; expanded abstract; typos correcte

Degradation of mangrove leaf litter by the tropical sesarmid crab Chiromanthes onychophorum

In high-diversity tropical mangrove swamps, the relationship between the breakdown to detritus of mangrove plant litter and secondary production of associated estuaries is little understood. This study examined one step in this relationship, the breakdown of mangrove leaf litter to detrital-sized particles by the sesarmid crab Chiromanthes onychophorum , locally very abundant in mangrove swamps of peninsular Malaysia. Contents of the proventriculus (stomach) and of the posterior hindgut, including rectum, were analyzed and particle sizes were measured. Gut contents consisted of more than 95% by volume of mangrove leaf fragments. Particles in the hindgut were of smaller mean size than those in the proventriculus. It is concluded that C. onychophorum consumes fallen leaves or their fragments, incompletely digests them, and returns them to the environment as fecal matter in a more finely-divided state than when they were ingested. C. onychophorum may therefore be a significant agent of mangrove leaf degradation to detrital-sized particles in swamp areas where it is abundant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46633/1/227_2004_Article_BF00455032.pd

The behaviour of random forest permutation-based variable importance measures under predictor correlation

<p>Abstract</p> <p>Background</p> <p>Random forests (RF) have been increasingly used in applications such as genome-wide association and microarray studies where predictor correlation is frequently observed. Recent works on permutation-based variable importance measures (VIMs) used in RF have come to apparently contradictory conclusions. We present an extended simulation study to synthesize results.</p> <p>Results</p> <p>In the case when both predictor correlation was present and predictors were associated with the outcome (H_A), the unconditional RF VIM attributed a higher share of importance to correlated predictors, while under the null hypothesis that no predictors are associated with the outcome (H₀) the unconditional RF VIM was unbiased. Conditional VIMs showed a decrease in VIM values for correlated predictors versus the unconditional VIMs under H_Aand was unbiased under H₀. Scaled VIMs were clearly biased under H_Aand H₀.</p> <p>Conclusions</p> <p>Unconditional unscaled VIMs are a computationally tractable choice for large datasets and are unbiased under the null hypothesis. Whether the observed increased VIMs for correlated predictors may be considered a "bias" - because they do not directly reflect the coefficients in the generating model - or if it is a beneficial attribute of these VIMs is dependent on the application. For example, in genetic association studies, where correlation between markers may help to localize the functionally relevant variant, the increased importance of correlated predictors may be an advantage. On the other hand, we show examples where this increased importance may result in spurious signals.</p