More elementary operators that are spectrally bounded

We discuss some necessary and some sufficient conditions for an elementary operator x↦∑ⁿ_i=1a_ixb_i on a Banach algebra A to be spectrally bounded. In the case of length three, we obtain a complete characterisation when A acts irreducibly on a Banach space of dimension greater than three.

Genomic instability after targeted irradiation of human lymphocytes: Evidence for inter-individual differences under bystander conditions

Environmental (222)radon exposure is a human health concern, and many studies demonstrate that very low doses of high LET alpha-particle irradiation initiate deleterious genetic consequences in both radiated and non-irradiated bystander cells. One consequence, radiation-induced genomic instability (RIGI), is a hallmark of tumorigenesis and is often assessed by measuring delayed chromosomal aberrations We utilised a technique that facilitates transient immobilization of primary lymphocytes for targeted microbeam irradiation and have reported that environmentally relevant doses, e.g. a single He-3(2+) particle traversal to a single cell, are sufficient to Induce RIGI Herein we sought to determine differences in radiation response in lymphocytes isolated from five healthy male donors Primary lymphocytes were irradiated with a single particle per cell nucleus. We found evidence for inter-individual variation in radiation response (Rid, measured as delayed chromosome aberrations) Although this was not highly significant, it was possibly masked by high levels of intra-individual variation While there are many studies showing a link between genetic predisposition and RIGI, there are few studies linking genetic background with bystander effects in normal human lymphocytes In an attempt to investigate inter-individual variation in the induction of bystander effects, primary lymphocytes were irradiated with a single particle under conditions where fractions of the population were traversed We showed a marked genotype-dependent bystander response in one donor after exposure to 15% of the population The findings may also be regarded as a radiation-induced genotype-dependent bystander effect triggering an instability phenotype (C) 2010 Elsevier B.V. All rights reserved.

Necessary conditions for demand revelation in double referenda

This paper demonstrates a set of necessary conditions that should generate unbiased, internally consistent estimates of willingness to pay (WTP) from a double referendum mechanism. These conditions are also sufficient for demand revelation in an experimental laboratory environment. However, the control over the mechanism achieved in the lab may not be transferrable to the field and WTP estimates derived from field surveys may remain biased. (c) 2008 Elsevier Inc. All rights reserved.

Palaeoglacial and palaeoclimatic conditions in the NW Pacific, as revealed by a morphometric analysis of cirques upon the Kamchatka Peninsula

The distribution of glacial cirques upon the Kamchatka peninsula, Far Eastern Russia, is systematically mapped from satellite images and digital elevation model data. A total of 3,758 cirques are identified, 238 of which are occupied by active glaciers. The morphometry of the remaining 3,520 cirques is analysed. These cirques are found to show a very strong N bias in their azimuth (orientation), likely resulting from aspect-related variations in insolation. The strength of this N bias is considered to indicate that former glaciation upon the peninsula was often ‘marginal’, and mainly of cirque-type, with peaks extending little above regional equilibrium-line altitudes. This is supported by the fact that S and SE-facing cirques are the highest in the dataset, suggesting that glacier-cover was rarely sufficient to allow S and SE-facing glaciers to develop at low altitudes. The strength of these azimuth-related variations in cirque altitude is thought to reflect comparatively cloud-free conditions during former periods of glaciation. It is suggested that these characteristics, of marginal glaciation and comparatively cloud-free conditions, reflect the region’s former aridity, which was likely intensified at the global Last Glacial Maximum, and during earlier periods of ice advance, as a result of the development of negative pressure anomalies over the North Pacific (driven by the growth of the Laurentide Ice Sheet), combined with other factors, including an increase in the extent and duration of sea ice, a reduction in global sea levels, cooler sea surface temperatures, and the localised growth of mountain glaciers. There is published evidence to suggest extensive glaciation of the Kamchatka Peninsula at times during the Late Quaternary, yet the data presented here appears to suggest that such phases were comparatively short-lived, and that smaller cirque-type glaciers were generally more characteristic of the period.