Synchronicity of Antarctic temperatures and local solar insolation on orbital timescales

The Milankovitch theory states that global climate variability on orbital timescales from tens to hundreds of thousands of years is dominated by the summer insolation at high northern latitudes. The supporting evidence includes reconstructed air temperatures in Antarctica that are nearly in phase with boreal summer insolation and out of phase with local summer insolation. Antarctic climate is therefore thought to be driven by northern summer insolation. A clear mechanism that links the two hemispheres on orbital timescales is, however, missing. We propose that key Antarctic temperature records derived from ice cores are biased towards austral winter because of a seasonal cycle in snow accumulation. Using present-day estimates of this bias in the 'recorder' system, here we show that the local insolation can explain the orbital component of the temperature record without having to invoke a link to the Northern Hemisphere. Therefore, the Antarctic ice-core-derived temperature record, one of the best-dated records of the late Pleistocene temperature evolution, cannot be used to support or contradict the Milankovitch hypothesis that global climate changes are driven by Northern Hemisphere summer insolation variations.     

Functional complementation between FADD and RIP1 in embryos and lymphocytes

FADD is a common adaptor shared by several death receptors for signalling apoptosis through recruitment and activation of caspase 8 (refs 1-3). Death receptors are essential for immune homeostasis, but dispensable during embryogenesis. Surprisingly, Fadd(-/-) mice die in utero and conditional deletion of FADD leads to impaired lymphocyte proliferation. How FADD regulates embryogenesis and lymphocyte responses has been a long-standing enigma. FADD could directly bind to RIP1 (also known as RIPK1), a serine/threonine kinase that mediates both necrosis and NF-κB activation. Here we show that Fadd(-/-) embryos contain raised levels of RIP1 and exhibit massive necrosis. To investigate a potential in vivo functional interaction between RIP1 and FADD, null alleles of RIP1 were crossed into Fadd(-/-) mice. Notably, RIP1 deficiency allowed normal embryogenesis of Fadd(-/-) mice. Conversely, the developmental defect of Rip1(-/-) lymphocytes was partially corrected by FADD deletion. Furthermore, RIP1 deficiency fully restored normal proliferation in Fadd(-/-) T cells but not in Fadd(-/-) B cells. Fadd(-/-)Rip1(-/-) double-knockout T cells are resistant to death induced by Fas or TNF-α and show reduced NF-κB activity. Therefore, our data demonstrate an unexpected cell-type-specific interplay between FADD and RIP1, which is critical for the regulation of apoptosis and necrosis during embryogenesis and lymphocyte function.     

American swallow bug, Oeciacus vicarius Horvath (Hemiptera: Cimicidae), in Hirundo rustica and Petrochelidon pyrrhonota nests in west central Colorado

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Oeciacus vicarious bed bugs were collected from 32% of Hirundo rustica nests and 83% of Petrochelidon pyrrhonota nests on bridges in western Colorado in December 1984. A total of 409 bugs (158 adults and 251 juveniles) were counted in 47 nests, two months after the hosts had departed for the winter.     

First record of pygmy rabbits ( Brachylagus idahoensis ) in Wyoming

Pygmy rabbits are reported for the first time in southwestern Wyoming. The range for this species is thus extended 240 km and 145 km from the nearest records in Idaho and Utah, respectively.     

Two distinct phosphorylation events govern the function of muscle FHOD3

Posttranslational modifications such as phosphorylation are universally acknowledged regulators of protein function. Recently we characterised a striated muscle-specific isoform of the formin FHOD3 that displays distinct subcellular targeting and protein half-life compared to its non-muscle counterpart and which is dependent on phosphorylation by CK2 (formerly casein kinase 2). We now show that the two isoforms of FHOD3 are already expressed in the vertebrate embryonic heart. Analysis of CK2 alpha knockout mice showed that phosphorylation by CK2 is also required for proper targeting of muscle FHOD3 to the myofibrils in embryonic cardiomyocytes in situ. The localisation of muscle FHOD3 in the sarcomere varies depending on the maturation state, being either broader or restricted to the Z-disc proper in the adult heart. Following myofibril disassembly, such as that in dedifferentiating adult rat cardiomyocytes in culture, the expression of non-muscle FHOD3 is up-regulated, which is reversed once the myofibrils are reassembled. The shift in expression levels of different isoforms is accompanied by an increased co-localisation with p62, which is involved in autophagy, and affects the half-life of FHOD3. Phosphorylation of three amino acids in the C-terminus of FHOD3 by ROCK1 is sufficient for activation, which results in increased actin filament synthesis in cardiomyocytes and also a broader localisation pattern of FHOD3 in the myofibrils. ROCK1 can directly phosphorylate FHOD3, and FHOD3 seems to be the downstream mediator of the exaggerated actin filament formation phenotype that is induced in cardiomyocytes upon the overexpression of constitutively active ROCK1. We conclude that the expression of the muscle FHOD3 isoform is characteristic of the healthy mature heart and that two distinct phosphorylation events are crucial to regulate the activity of this isoform in thin filament assembly and maintenance.     

An augmented BV setting for feedback switching control

<正> This paper considers dynamical systems under feedback with control actions limited toswitching.The authors wish to understand the closed-loop systems as approximating multi-scale problemsin which the implementation of switching merely acts on a fast scale.Such hybrid dynamicalsystems are extensively studied in the literature,but not much so far for feedback with partial stateobservation.This becomes in particular relevant when the dynamical systems are governed by partialdifferential equations.The authors introduce an augmented BV setting which permits recognition ofcertain fast scale effects and give a corresponding well-posedness result for observations with such minimalregularity.As an application for this setting,the authors show existence of solutions for systemsof semilinear hyperbolic equations under such feedback with pointwise observations.     

Regional econometric income forecast accuracy

Econometric prediction accuracy for personal income forecasts is examined for a region of the United States. Previously published regional structural equation model (RSEM) forecasts exist ex ante for the state of New Mexico and its three largest metropolitan statistical areas: Albuquerque, Las Cruces and Santa Fe. Quarterly data between 1983 and 2000 are utilized at the state level. For Albuquerque, annual data from 1983 through 1999 are used. For Las Cruces and Santa Fe, annual data from 1990 through 1999 are employed. Univariate time series, vector autoregressions and random walks are used as the comparison criteria against structural equation simulations. Results indicate that ex ante RSEM forecasts achieved higher accuracy than those simulations associated with univariate ARIMA and random walk benchmarks for the state of New Mexico. The track records of the structural econometric models for Albuquerque, Las Cruces and Santa Fe are less impressive. In some cases, VAR benchmarks prove more reliable than RSEM income forecasts. In other cases, the RSEM forecasts are less accurate than random walk alternatives. Copyright © 2005 John Wiley & Sons, Ltd.     

Selection of Value‐at‐Risk models

Value‐at‐Risk (VaR) is widely used as a tool for measuring the market risk of asset portfolios. However, alternative VaR implementations are known to yield fairly different VaR forecasts. Hence, every use of VaR requires choosing among alternative forecasting models. This paper undertakes two case studies in model selection, for the S&P 500 index and India's NSE‐50 index, at the 95% and 99% levels. We employ a two‐stage model selection procedure. In the first stage we test a class of models for statistical accuracy. If multiple models survive rejection with the tests, we perform a second stage filtering of the surviving models using subjective loss functions. This two‐stage model selection procedure does prove to be useful in choosing a VaR model, while only incompletely addressing the problem. These case studies give us some evidence about the strengths and limitations of present knowledge on estimation and testing for VaR. Copyright © 2003 John Wiley & Sons, Ltd.