The suppression of star formation by powerful active galactic nuclei

The old, red stars that constitute the bulges of galaxies, and the massive black holes at their centres, are the relics of a period in cosmic history when galaxies formed stars at remarkable rates and active galactic nuclei (AGN) shone brightly as a result of accretion onto black holes. It is widely suspected, but unproved, that the tight correlation between the mass of the black hole and the mass of the stellar bulge results from the AGN quenching the surrounding star formation as it approaches its peak luminosity. X-rays trace emission from AGN unambiguously, whereas powerful star-forming galaxies are usually dust-obscured and are brightest at infrared and submillimetre wavelengths. Here we report submillimetre and X-ray observations that show that rapid star formation was common in the host galaxies of AGN when the Universe was 2-6 billion years old, but that the most vigorous star formation is not observed around black holes above an X-ray luminosity of 10(44) ergs per second. This suppression of star formation in the host galaxy of a powerful AGN is a key prediction of models in which the AGN drives an outflow, expelling the interstellar medium of its host and transforming the galaxy's properties in a brief period of cosmic time.     

An analysis on the predictability of CAPM beta for momentum returns

This paper demonstrates that the forecasted capital asset pricing model (CAPM) beta of momentum portfolios explains a large portion of the return, ranging from 40% to 60% for stock‐level momentum, and from 30% to 50% for industry‐level momentum. Beta forecasts are from a realized beta estimator using daily returns over the prior year. Periods such as 1969–1989 have been found in earlier studies to contain abnormal profits from momentum trading; however, we show that these were spuriously generated by measurement error in systematic risk. These results cast further doubt on the ability of standard momentum trading strategies to generate abnormal profits.     

On the action of vitamin C on the neuromuscular junctions.

High concentrations of ascorbic acid produce complete blockage of the transmission of nervous stimuli on the isolated neuromuscular preparation of phrenic nerve-hemidiaphragm of the rat.     

Wound healing properties of naphthaquinone pigments fromAlkanna tinctoria

Summary From the roots ofAlkanna tinctoria Tausch, the alkannin esters of the following acids were isolated and identified: ,-dimethylacrylic acid, -acetoxy-isovaleric acid, isovaleric acid, and angelic acid. These esteric pigments showed excellent wound healing properties in a clinical study on 72 patients with ulcus cruris.I thank Dr A. Winkler, Heidberg Hospital and Prof. K. Kanitakis, Aristotle University, for the clinical studies. Prof. A. Sagredos, Aristotle University, for his help and Dr C. Gairola, Tobacco and Health Research Institute, for the mutagenicity tests. I also thank Dr G. A. Digenis and Dr L. Hurley, University of Kentucky, College of Pharmacy, for their critical reviews and comments.     

A novel 72-kDa leukocyte-derived osteoglycin enhances the activation of toll-like receptor 4 and exacerbates cardiac inflammation during viral myocarditis

Background

Viral myocarditis can severely damage the myocardium through excessive infiltration of immune cells. Osteoglycin (OGN) is part of the small leucine-rich repeat proteoglycan (SLRP) family. SLRP’s may affect inflammatory and fibrotic processes, but the implication of OGN in cardiac inflammation and the resulting injury upon viral myocarditis is unknown.

Methods and results

This study uncovered a previously unidentified 72-kDa variant of OGN that is predominant in cardiac human and mouse samples of viral myocarditis. Its absence in mice significantly decreased cardiac inflammation and injury in Coxsackievirus-B3-induced myocarditis. It also delayed mortality in lipopolysaccharide-induced endotoxemia going along with a reduced systemic production of pro-inflammatory cytokines. This 72-kDa OGN is expressed in the cell membrane of circulating and resident cardiac macrophages and neutrophils. Co-immunoprecipitation and OGN siRNA experiments revealed that this 72-kDa variant activates the toll-like receptor-4 (TLR4) with a concomitant increase in IL-6, TNF-α, IL-1β, and IL-12 expression. This immune cell activation by OGN occurred via MyD88 and increased phosphorylation of c-jun. Finally, the 72-kDa chondroitin sulfate is the result of O-linked glycosylation of the 32-kDa protein core of OGN. In contrast, the 34-kDa dermatan sulfate-OGN, involved in collagen cross linking, was also the result of O-linked glycosylation.

Conclusion

The current study discovered a novel 72-kDa chondroitin sulfate-OGN that is specific for innate immune cells. This variant is able to bind and activate TLR4. The absence of OGN decreases cytokine production by both circulating and cardiac leukocytes upon (systemic) LPS exposure, and reduces cardiac inflammation and injury in viral myocarditis.

     

Long‐term sales forecasting using holt–winters and neural network methods

The problem of medium to long‐term sales forecasting raises a number of requirements that must be suitably addressed in the design of the employed forecasting methods. These include long forecasting horizons (up to 52 periods ahead), a high number of quantities to be forecasted, which limits the possibility of human intervention, frequent introduction of new articles (for which no past sales are available for parameter calibration) and withdrawal of running articles. The problem has been tackled by use of a damped‐trend Holt–Winters method as well as feedforward multilayer neural networks (FMNNs) applied to sales data from two German companies. Copyright © 2005 John Wiley & Sons, Ltd.     

Submillimetre galaxies reside in dark matter haloes with masses greater than 3 × 10(11) solar masses

The extragalactic background light at far-infrared wavelengths comes from optically faint, dusty, star-forming galaxies in the Universe with star formation rates of a few hundred solar masses per year. These faint, submillimetre galaxies are challenging to study individually because of the relatively poor spatial resolution of far-infrared telescopes. Instead, their average properties can be studied using statistics such as the angular power spectrum of the background intensity variations. A previous attempt at measuring this power spectrum resulted in the suggestion that the clustering amplitude is below the level computed with a simple ansatz based on a halo model. Here we report excess clustering over the linear prediction at arcminute angular scales in the power spectrum of brightness fluctuations at 250, 350 and 500?μm. From this excess, we find that submillimetre galaxies are located in dark matter haloes with a minimum mass, M(min), such that log(10)[M(min)/M(⊙)] = 11.5(+0.7)(-0.2) at 350?μm, where M(⊙) is the solar mass. This minimum dark matter halo mass corresponds to the most efficient mass scale for star formation in the Universe, and is lower than that predicted by semi-analytical models for galaxy formation.     

On the action of vitamin C on the neuromuscular junctions

Summary High concentrations of ascorbic acid produce complete blockage of the transmission of nervous stimuli on the isolated neuromuscular preparation of phrenic nerve-hemidiaphragm of the rat.