The 44Ti(α, p) reaction and its implication on the 44Ti yield in supernovae

Cross sections for the 44Ti(α, p)47V reaction which significantly affects the yield of 44Ti in supernovae were measured in the energy range 5.7MeV ≤ Ec.m. ≤ 9 MeV, using a beam of radioactive 44Ti. The cross sections and the deduced astrophysical reaction rates are larger than the results from theoretical calculations by about a factor of 2. The implications of this increase in the reaction rate for the search of supernovae using space-based gamma detectors are discussed

Education for sustainable development (ESD): the turn away from ‘environment’ in environmental education?

This article explores the implications of the shift of environmental education (EE) towards education for sustainable development (ESD) in the context of environmental ethics. While plural perspectives on ESD are encouraged both by practitioners and researchers of EE, there is also a danger that such pluralism may sustain dominant political ideologies and consolidated corporate power that obscure environmental concerns. Encouraging plural interpretations of ESD may in fact lead ecologically ill-informed teachers and students acculturated by the dominant neo-liberal ideology to underprivilege ecocentric perspective. It is argued that ESD, with its focus on human welfare, equality, rights and fair distribution of resources is a radical departure from the aim of EE set out by the Belgrade Charter as well as a distinct turn towards anthropocentrically biased education. This article has two aims: to demonstrate the importance of environmental ethics for EE in general and ESD in particular and to argue in favour of a return to instrumentalism, based on the twinned assumptions that the environmental problems are severe and that education of ecologically minded students could help their resolution

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Advanced concept proof-of-principle demonstration: Switchable radioactive neutron source

An advanced concept proof-of-principle demonstration was successfully performed to show the feasibility of a practical switchable radioactive neutron source (SRNS) that can be switched on and off like an accelerator, but without requiring accelerator equipment such as high voltage supply, control unit, etc. This source concept would provide a highly portable neutron source for field radiation measurement applications. Such a source would require minimal, if any, shielding when not in use. The SRNS, previously patented by Argonne staff, provides a means of constructing the alpha-emitting and light-element components of a radioactive neutron source, in such a fashion that these two components can brought together to turn the source ``on`` and then be separated to turn the source ``off``. An SRNS could be used for such field applications as active neutron interrogation of objects to detect fissile materials or to measure their concentration; and to excite gamma-ray emission for detection of specific elements that indicate toxic chemicals, drugs, explosives, etc. The demonstration was performed using Pu-238 as the alpha emitter and Be as the light element, in an air-atmosphere glovebox having no atmosphere purification capability. A stable, thin film of Pu-238 oxide was deposited on a stainless steel planchet. The ``on`` output of the demonstration Pu-238 film was measured to be 2.5 {times} 10{sup 6} neutrons/sec-gram of Pu-238. The measured ``off`` neutron rate was satisfactory, only about 5% of the ``on`` output, after two weeks of exposure to the glovebox atmosphere. After several weeks additional exposure, the ``off`` rate had increased to about 15%. This work demonstrates the feasibility of constructing practical, highly portable SRNS units with very low gamma-ray dose in the ``off`` position

Inducible responses in the brown seaweed Ecklonia cava: the role of grazer identity and season

1 Plants must either tolerate consumption or defend themselves against grazer attacks. Selection for phenotypically plastic antiherbivory responses has been suggested for many plants, including a few species of seaweed, but little is known about its specificity or seasonality. 2 Multi-factorial experiments tested the effects of consumer identity (Littorina brevicula vs. Haliotis discus) and season (summer vs. autumn) on the induction of antiherbivory defences in the brown seaweed Ecklonia cava. Following a grazer-free acclimation phase, algae were incubated with grazers (treatment phase) and, subsequently, without grazers (recovery phase). Feeding preference assays, were used to assess differences in consumption rates between grazer-exposed and control plants. 3 In summer, Littorina, but not Haliotis, induced defence in Ecklonia. This defence vanished by the end of the recovery phase. In autumn, neither exposure to direct attack nor to waterborne cues induced defensive responses. 4 Both consumer identity and season of consumption can influence the ability of a given macroalgal species to induce antiherbivory defences. Tailoring such responses to spatial and temporal variation in grazer pressure could have profound ecological implications, for example changing food webs and community structure