Associations between Quantitative Mobility Measures Derived from Components of Conventional Mobility Testing and Parkinsonian Gait in Older Adults

Objective: To provide objective measures which characterize mobility in older adults assessed in the community setting and to examine the extent to which these measures are associated with parkinsonian gait. Methods: During conventional mobility testing in the community-setting, 351 ambulatory non-demented Memory and Aging Project participants wore a belt with a whole body sensor that recorded both acceleration and angular velocity in 3 directions. We used measures derived from these recordings to quantify 5 subtasks including a) walking, b) transition from sit to stand, c) transition from stand to sit, d) turning and e) standing posture. Parkinsonian gait and other mild parkinsonian signs were assessed with a modified version of the original Unified Parkinson’s Disease Rating Scale (mUPDRS). Results: In a series of separate regression models which adjusted for age and sex, all 5 mobility subtask measures were associated with parkinsonian gait and accounted for 2% to 32% of its variance. When all 5 subtask measures were considered in a single model, backward elimination showed that measures of walking sit to stand and turning showed independent associations with parkinsonian gait and together accounted for more than 35% of its variance. Cross-validation using data from a 2nd group of 258 older adults showed similar results. In similar analyses, only walking was associated with bradykinesia and sway with tremor. Interpretation Quantitative mobility subtask measures vary in their associations with parkinsonian gait scores and other parkinsonian signs in older adults. Quantifying the different facets of mobility has the potential to facilitate the clinical characterization and understanding the biologic basis for impaired mobility in older adults

All-Pay Auctions with Weakly Risk-Averse Buyers

We use perturbation analysis to study independent private-value all-pay auctions with weakly risk-averse buyers. We show that under weak risk aversion: 1) Buyers with low values bid lower and buyers with high values bid higher than they would bid in the risk neutral case. 2) Buyers with low values bid lower and buyers with high values bid higher than they would bid in a first-price auction. 3) Buyers' expected utilities in an all-pay auction are lower than in a first-price auction. 4) The seller's expected payoff in an all-pay auction may be either higher or lower than in the risk neutral case. 5) The seller's expected payoff in an all-pay auction may be either higher or lower than in a first-price auction

A C. elegans Model for Mitochondrial Fatty Acid Synthase II: The Longevity-Associated Gene W09H1.5/mecr-1 Encodes a 2-trans-Enoyl-Thioester Reductase

Our recognition of the mitochondria as being important sites of fatty acid biosynthesis is continuously unfolding, especially in light of new data becoming available on compromised fatty acid synthase type 2 (FASII) in mammals. For example, perturbed regulation of murine 17β-HSD8 encoding a component of the mitochondrial FASII enzyme 3-oxoacyl-thioester reductase is implicated in polycystic kidney disease. In addition, over-expression in mice of the Mecr gene coding for 2-trans-enoyl-thioester reductase, also of mitochondrial FASII, leads to impaired heart function. However, mouse knockouts for mitochondrial FASII have hitherto not been reported and, hence, there is a need to develop alternate metazoan models such as nematodes or fruit flies. Here, the identification of Caenorhabditis elegans W09H1.5/MECR-1 as a 2-trans-enoyl-thioester reductase of mitochondrial FASII is reported. To identify MECR-1, Saccharomyces cerevisiae etr1Δ mutant cells were employed that are devoid of mitochondrial 2-trans-enoyl-thioester reductase Etr1p. These yeast mutants fail to synthesize sufficient levels of lipoic acid or form cytochrome complexes, and cannot respire or grow on non-fermentable carbon sources. A mutant yeast strain ectopically expressing nematode mecr-1 was shown to contain reductase activity and resemble the self-complemented mutant strain for these phenotype characteristics. Since MECR-1 was not intentionally targeted for compartmentalization using a yeast mitochondrial leader sequence, this inferred that the protein represented a physiologically functional mitochondrial 2-trans-enoyl-thioester reductase. In accordance with published findings, RNAi-mediated knockdown of mecr-1 in C. elegans resulted in life span extension, presumably due to mitochondrial dysfunction. Moreover, old mecr-1(RNAi) worms had better internal organ appearance and were more mobile than control worms, indicating a reduced physiological age. This is the first report on RNAi work dedicated specifically to curtailing mitochondrial FASII in metazoans. The availability of affected survivors will help to position C. elegans as an excellent model for future pursuits in the emerging field of mitochondrial FASII research

Planeamiento de la Incorporación de energía Eoloeléctrica a la Red pública

Se establecen las premisas básicas para el planeamiento de la incorporación de la energía eoloeléctrica (EEE) a los Sistemas Interconectados.Los aspectos considerados se presentan desde el punto de vista de la aerogeneración de potencia y del planeamiento energético, destacando las bases para un modelo de oferta, en cuyo desarrollo computacional se trabaja actualmente. Este modelo requiere de solo dos variables que deben determinarse exógenamente: la demanda de Energía Eléctrica y la prospección del recurso eólico. El resto de la información (costo de recursos alternativos, política de sustituciones, disponibilidad tecnológica, etc.) es provista por interrelaciones submodelos contenidos en el modelo agregado.Considerando la existencia de numerosos sistemas predominantemente térmicos en Latinoamérica, la implementación de un modelo como el propuesto puede significar un interesante aporte a la diversificación de energéticos primarios de dichos sistemas y por lo tanto, un ahorro significativo de energéticos fósiles.