Globular clusters, Hipparcos, and the age of the galaxy

We discuss the impact of the results from the recent Hipparcos astrometric satellite on distance estimates of galactic globular clusters. Recalibrating the clusters not only implies a relatively small change in the distance to the Large Magellanic Cloud, and hence a rescaling of several estimates of the Hubble constant, but also leads to significantly younger cluster ages. Although the data are not yet conclusive, the results so far point to a likely resolution of the apparent paradox of a universe younger than its constituents, without requiring significant modifications to simple cosmological models.

The age of the universe from nuclear chronometers

An overview is presented of the current situation regarding radioactive dating of the matter of which our Galaxy is comprised. A firm lower bound on the age from nuclear chronometers of ≈9–10 Gyr is entirely consistent with age determinations from globular clusters and white dwarf cooling histories. The reasonable assumption of an approximately uniform nucleosynthesis rate yields an age for the Galaxy of 12.8 ± 3 Gyr, which again is consistent with current determinations from other methods.

A polygenic mouse model of psoriasiform skin disease in CD18-deficient mice.

Previously, a hypomorphic mutation in CD18 was generated by gene targeting, with homozygous mice displaying increased circulating neutrophil counts, defects in the response to chemically induced peritonitis, and delays in transplantation rejection. When this mutation was backcrossed onto the PL/J inbred strain, virtually all homozygous mice developed a chronic inflammatory skin disease with a mean age of onset of 11 weeks after birth. The disease was characterized by erythema, hair loss, and the development of scales and crusts. The histopathology revealed hyperplasia of the epidermis, subcorneal microabscesses, orthohyperkeratosis, parakeratosis, and lymphocyte exocytosis, which are features in common with human psoriasis and other hyperproliferative inflammatory skin disorders. Repetitive cultures failed to demonstrate bacterial or fungal organisms potentially involved in the pathogenesis of this disease, and the dermatitis resolved rapidly after subcutaneous administration of dexamethasone. Homozygous mutant mice on a (PL/J x C57BL/6J)F1 background did not develop the disease and backcross experiments suggest that a small number of genes (perhaps as few as one), in addition to CD18, determine susceptibility to the disorder. This phenotype provides a model for inflammatory skin disorders, may have general relevance to polygenic human inflammatory diseases, and should help to identify genes that interact with the beta2 integrins in inflammatory processes.

Apolipoprotein E4 allele as a predictor of cholinergic deficits and treatment outcome in Alzheimer disease.

Apolipoprotein E (apoE) is critical in the modulation of cholesterol and phospholipid transport between cells of different types. Human apoE is a polymorphic protein with three common alleles, APO epsilon 2, APO epsilon 3, and APO epsilon 4. ApoE4 is associated with sporadic and late-onset familial Alzheimer disease (AD). Gene dose was shown to have an effect on risk of developing AD, age of onset, accumulation of senile plaques in the brain, and reduction of choline acetyltransferase (ChAT) activity in the hippocampus of AD subjects. To characterize the possible impact of the apoE4 allele on cholinergic markers in AD, we examined the effect of apoE4 allele copy number on pre- and postsynaptic markers of cholinergic activity. ApoE4 allele copy number showed an inverse relationship with residual brain ChAT activity and nicotinic receptor binding sites in both the hippocampal formation and the temporal cortex of AD subjects. AD cases lacking the apoE4 allele showed ChAT activities close or within age-matched normal control values. The effect of the apoE4 allele on cholinomimetic drug responsiveness was assessed next in a group (n = 40) of AD patients who completed a double-blind, 30-week clinical trial of the cholinesterase inhibitor tacrine. Results showed that > 80% of apoE4-negative AD patients showed marked improvement after 30 weeks as measured by the AD assessment scale (ADAS), whereas 60% of apoE4 carriers had ADAS scores that were worse compared to baseline. These results strongly support the concept that apoE4 plays a crucial role in the cholinergic dysfunction associated with AD and may be a prognostic indicator of poor response to therapy with acetylcholinesterase inhibitors in AD patients.

Genetic dissection of Alzheimer disease, a heterogeneous disorder.

The genetics of Alzheimer disease (AD) are complex and not completely understood. Mutations in the amyloid precursor protein gene (APP) can cause early-onset autosomal dominant AD. In vitro studies indicate that cells expressing mutant APPs overproduce pathogenic forms of the A beta peptide, the major component of AD amyloid. However, mutations in the APP gene are responsible for 5% or less of all early-onset familial AD. A locus on chromosome 14 is responsible for AD in other early-onset AD families and represents the most severe form of the disease in terms of age of onset and rate of decline. Attempts to identify the AD3 gene by positional cloning methods are underway. At least one additional early-onset AD locus remains to be located. In late-onset AD, the apolipoprotein E gene allele epsilon 4 is a risk factor for AD. This allele appears to act as a dose-dependent age-of-onset modifier. The epsilon 2 allele of this gene may be protective. Other late-onset susceptibility factors remain to be identified.

The Dragon Tree in the Age of Exploration

he dragon tree, a peculiar species native to Socotra, southwest Arabia, east Africa, Morocco, Macaronesia, and the Canary islands, possesses an intriguing iconographic history. The first wave of images date from 1470 to 1550, beginning with Martin Schongauer’s 1470 engraving of The Flight into Egypt. These depictions portray the dragon tree in the context of a handful of biblical themes and with apparent symbolic import. After 1550, religious images of the dragon tree vanish abruptly and are replaced by representations of an empirical nature. Dragon tree iconography is notable for the extent to which it did and did not leave an impression on European art. In this paper I examine the inability of dragon tree images to gain the momentum required to propel them into European iconography more permanently, and the forces that may account for the abrupt change from biblical to botanical renderings.

An Independent Art Movement: The Independent Artist, Community Television, and the Age of Information

The history of community television shows that it has been a home to activist and non-profit organizations that have created programs focused on freedom of speech. This project proposes that community television is also a place where artists can have freedom of artistic expression. The reflective paper reviews the creation of my film designed to inform and attract artists to community television. In it I critically reflect on the artistic, technical, artistic/technical, and production changes made throughout my journey from being a visual artist to becoming a video-artist. The reflective paper, along with the film, act as a wake-up call to artists who are unaware of community television and the advantages it has to offer them.

Human Resources (HR) in the Age of Technology: An Examination of the Relationship Between HR and Technology

Technology helps the Human Resources (HR) department drive for strategic relevance. These two departments are successfully collaborating on major projects in such business-critical areas as e-recruiting, self-service, training, compensation and talent management. Technology is critical in helping increase efficiency, increase attraction and retention, reduce administration and cut costs. In recent years, HR information systems (HRIS) have become more important than ever, this time as an essential part of a company's information security and knowledge fields. Ill-suited benefits and disorganized resources are history; now is the time for customized, dynamic plans and connected systems. Employees will appreciate the HRIS, business will benefit from the HRIS and the HR department will no longer have to be the ugly duckling of the company.

Technical efficiency in the retail food industry: the influence of inventory investment, wage levels, and age of the firm

The objective of this paper is to estimate technical efficiency in retailing; and the influence of inventory investment, wage levels, and firm age on this efficiency. We use the output supermarket chains’ sales volume, calculated isolating the retailer price effect on its sales revenue. This output allows us to estimate a strictly technical concept of efficiency. The methodology is based on the estimation of a stochastic parametric function. The empirical analyses applied to panel data on a sample of 42 supermarket chains between 2000 and 2002 show that inventory investment and wage level have an impact on technical efficiency. In comparison, the effect of these factors on efficiency calculated through a monetary output (sales revenue) shows some differences that could be due to aspects related to product prices.

Prehistoric man, Hall of the Stone Age of the Old World / by Henry Field, Assistant Curator of Physical Anthropology. Foreword by Berthold Laufer -- 8 plates in photogravure and 1 map.

no.31(1933)

The Mammalian faunas of the Washakie Formation, Eocene Age, of Southern Wyoming. Introduction: The geology, history, and setting / William D. Turnbull --.

v.33:no.30(1978)

Death Threat Letters: Allegories of American Authorship in the Age of Terrorism

This dissertation examines novels that use terrorism to allegorize the threatened position of the literary author in contemporary culture. Allegory is a term that has been differently understood over time, but which has consistently been used by writers to articulate and construct their roles as authors. In the novels I look at, the terrorist challenge to authorship results in multiple deployments of allegory, each differently illustrating the way that allegory is used and authorship constructed in the contemporary American novel. Don DeLillo’s Mao II (1991), first puts terrorists and authors in an oppositional pairing. The terrorist’s ability to traffic in spectacle is presented as indicative of the author’s fading importance in contemporary culture and it is one way that terrorism allegorizes threats to authorship. In Philip Roth’s Operation Shylock (1993), the allegorical pairing is between the text of the novel and outside texts – newspaper reports, legal cases, etc. – that the novel references and adapts in order to bolster its own narrative authority. Richard Powers’s Plowing the Dark (1999) pairs the story of an imprisoned hostage, craving a single book, with employees of a tech firm who are creating interactive, virtual reality artworks. Focusing on the reader’s experience, Powers’s novel posits a form of authorship that the reader can take into consideration, but which does not seek to control the experience of the text. Finally, I look at two of Paul Auster’s twenty-first century novels, Travels in the Scriptorium (2007) and Man in the Dark (2008), to suggest that the relationship between representations of authors and terrorists changed after 9/11. Auster’s author-figures forward an ethics of authorship whereby novels can use narrative to buffer readers against the portrayal of violent acts in a culture that is suffused with traumatizing imagery.