the american naturalist

One main goal of forest ecology is to infer past changes and predict future changes in species composition, and examining the diameter distributions of canopy species is often used toward this end Theory indicates that higher rates of population change, λ, lead to the process of being eliminated from the forest-perhaps more steeply declining size distributions (more juveniles relative during succession-fail to reproduce and thus lack sufto adults). But other parameters also affect the size distribution: ficient advanced regeneration. ''The lack of congruence lower growth rate of juveniles and lower survival at any size pro-between overstory and understory in these stands is both duce more steeply declining size distributions as well. Empirical an indicator of change as well as a major concern for evaluation of 216 tree populations showed that juvenile growth conservation' ' (Foster et al. 1996, p. 420). In the tropics, was the strongest predictor of size distribution, in the direction the use of diameter distributions to project community predicted by theory. Size distribution did correlate with population growth, but weakly and only in understory species, not canopy change has been especially important in Africa, and sevspecies. Size distribution did not correlate with the growth rate of eral early studies suggested that dominant canopy species larger individuals nor with survival. Results suggest that static in-in African forests do not produce juveniles in the immeformation on the size distribution is not a good predictor of future diate area. This led to the idea of cyclical succession, or population trends, while demographic information is. Fast-grow-the mosaic theory of regeneration provide in-depth analyses of these ideas, using extensive quantitative data on size distributions. But the underlying assumption-that populations with low juvenile density relative to adult density are in deEcologists often use size distribution to indicate the cline-has not been explicitly tested. Here we address health of a population. If there are large numbers of ju-two ways of making this test. We first employ a theoretical approach, examining quantitative population models * E-mail: [email protected]. to determine how size distribution relates to population † E-mail: [email protected]. growth. Then we proceed with a direct, empirical test us- ‡ E-mail: [email protected]. ing records of population change over 13 yr in a tree § E-mail: [email protected]. community. In all 216 species abundant enough to ana

The Aussie, 1918-1931: cartoons, digger remembrance and First World War identity

Feelings of community, cultural definition and memory were kept alive through the soldiers’ mass circulation tabloid, the Aussie, examined here in the light of theorization of memory and representation, applied to both text and cartoons. The publication’s aim for veterans’ values to become shared national values is analysed in the light of its high profile usage of soft cartoon humour and also of nostalgia – highlighting the limitations as well as the effectiveness in terms of Australia’s evolving national identity. When the post-war economic situation worsened, deeper issues of national tension were glossed over by the use of scapegoats such as ‘profiteers’ and ‘lazy workers’. The armed forces were obliged to take on a political role of lobbying for their cause, but the Aussie as ‘cheerful friend’ experienced its own identity crisis that proved to be terminal

Genomic-Bioinformatic Analysis of Transcripts Enriched in the Third-Stage Larva of the Parasitic Nematode Ascaris suum

Differential transcription in Ascaris suum was investigated using a genomic-bioinformatic approach. A cDNA archive enriched for molecules in the infective third-stage larva (L3) of A. suum was constructed by suppressive-subtractive hybridization (SSH), and a subset of cDNAs from 3075 clones subjected to microarray analysis using cDNA probes derived from RNA from different developmental stages of A. suum. The cDNAs (n = 498) shown by microarray analysis to be enriched in the L3 were sequenced and subjected to bioinformatic analyses using a semi-automated pipeline (ESTExplorer). Using gene ontology (GO), 235 of these molecules were assigned to ‘biological process’ (n = 68), ‘cellular component’ (n = 50), or ‘molecular function’ (n = 117). Of the 91 clusters assembled, 56 molecules (61.5%) had homologues/orthologues in the free-living nematodes Caenorhabditis elegans and C. briggsae and/or other organisms, whereas 35 (38.5%) had no significant similarity to any sequences available in current gene databases. Transcripts encoding protein kinases, protein phosphatases (and their precursors), and enolases were abundantly represented in the L3 of A. suum, as were molecules involved in cellular processes, such as ubiquitination and proteasome function, gene transcription, protein–protein interactions, and function. In silico analyses inferred the C. elegans orthologues/homologues (n = 50) to be involved in apoptosis and insulin signaling (2%), ATP synthesis (2%), carbon metabolism (6%), fatty acid biosynthesis (2%), gap junction (2%), glucose metabolism (6%), or porphyrin metabolism (2%), although 34 (68%) of them could not be mapped to a specific metabolic pathway. Small numbers of these 50 molecules were predicted to be secreted (10%), anchored (2%), and/or transmembrane (12%) proteins. Functionally, 17 (34%) of them were predicted to be associated with (non-wild-type) RNAi phenotypes in C. elegans, the majority being embryonic lethality (Emb) (13 types; 58.8%), larval arrest (Lva) (23.5%) and larval lethality (Lvl) (47%). A genetic interaction network was predicted for these 17 C. elegans orthologues, revealing highly significant interactions for nine molecules associated with embryonic and larval development (66.9%), information storage and processing (5.1%), cellular processing and signaling (15.2%), metabolism (6.1%), and unknown function (6.7%). The potential roles of these molecules in development are discussed in relation to the known roles of their homologues/orthologues in C. elegans and some other nematodes. The results of the present study provide a basis for future functional genomic studies to elucidate molecular aspects governing larval developmental processes in A. suum and/or the transition to parasitism

Improving the energy performance of UK households: Results from surveys of consumer adoption and use of low- and zero carbon technologies

This paper presents results from a UK Open University project which surveyed consumers' reasons for adoption, and non-adoption, of energy efficiency measures and renewable energy systems–collectively called low- and zero-carbon technologies–and their experiences of using these technologies. Data were gathered during 2006 via an online questionnaire with nearly 400 responses, plus 111 in-depth telephone interviews. The respondents were mainly environmentally concerned, 'green' consumers and therefore these are purposive rather than representative surveys. The paper outlines results for four energy efficiency measures (loft insulation, condensing boilers, heating controls and energy-efficient lighting) and four household renewables (solar thermal water heating, solar photovoltaics, micro-wind turbines and wood-burning stoves). These green consumers typically adopted these technologies to save energy, money and/or the environment, which many considered they achieved despite rebound effects. The reasons for considering but rejecting these technologies include the familiar price barriers, but there were also other obstacles that varied according to the technology concerned. Nearly a third of the surveyed consumers had adopted household renewables, over half of which were wood stoves and 10% solar thermal water heating systems. Most adopters of renewables had previously installed several energy efficiency measures, but only a fifth of those who seriously considered renewables actually installed a system. This suggests sell energy efficiency first, then renewables. There seems to be considerable interest in household renewables in the UK, especially among older, middle-class green consumers, but so far only relatively few pioneers have managed to overcome the barriers to adoption

A pragmatic approach to resolving technological unfairness: The case of Nike’s Vaporfly & Alphafly running footwear

Background Technology is often introduced into sport to facilitate it or to improve human performance within it. On occasion, some forms of novel technology require regulation or prevention entirely to ensure that a sport remains fair and accessible. Recently, the Nike Vaporfly and Alphafly shoes have received some concerns over their appropriateness for use in competitive distance running. Methods This paper evaluates the use of these shoes against an existing framework for sports technology discourse and adopts a pragmatic approach to attempt to resolve them. Results It is proposed that the three concerns regarding cost, access and coercion cannot be ruled out but likely remain short term issues. As a result, it is proposed that these running shoes are acceptable forms of technology but that ongoing vigilance will be required as such technologies develop further in the future. Conclusions The Nike Vaporfly/Alphafly shoes do push the perceived acceptability of running shoes to the limits of the current sports regulations. However, the alleged gains have not manifested themselves to a level that could be considered excessive when reviewing historical performances or when evaluated against a set of well-cited criteria. The sport will need to adopt a stance of ongoing vigilance as such technologies continue to develop or be optimised in the future

The origin of the x-ray emission from the high-velocity cloud MS30.7-81.4-118

A soft X-ray enhancement has recently been reported toward the high-velocity cloud MS30.7-81.4-118 (MS30.7), a constituent of the Magellanic Stream. In order to investigate the origin of this enhancement, we have analyzed two overlapping XMM-Newton observations of this cloud. We find that the X-ray enhancement is 6??? or 100 pc across, and is concentrated to the north and west of the densest part of the cloud. We modeled the X-ray enhancement with a variety of spectral models. A single-temperature equilibrium plasma model yields a temperature of and a 0.4-2.0 keV luminosity of 7.9 ?? 1033 erg s-1. However, this model underpredicts the on-enhancement emission around 1 keV, which may indicate the additional presence of hotter plasma (T ≳ 107 K), or that recombination emission is important. We examined several different physical models for the origin of the X-ray enhancement. We find that turbulent mixing of cold cloud material with hot ambient material, compression or shock heating of a hot ambient medium, and charge exchange reactions between cloud atoms and ions in a hot ambient medium all lead to emission that is too faint. In addition, shock heating in a cool or warm medium leads to emission that is too soft (for reasonable cloud speeds). We find that magnetic reconnection could plausibly power the observed X-ray emission, but resistive magnetohydrodynamical simulations are needed to test this hypothesis. If magnetic reconnection is responsible for the X-ray enhancement, the observed spectral properties could potentially constrain the magnetic field in the vicinity of the Magellanic Stream.open1

Vascular function assessed with cardiovascular magnetic resonance predicts survival in patients with advanced chronic kidney disease

<p>Abstract</p> <p>Background</p> <p>Increased arterial stiffness is associated with mortality in patients with chronic kidney disease. Cardiovascular magnetic resonance (CMR) permits assessment of the central arteries to measure aortic function.</p> <p>Methods</p> <p>We studied the relationship between central haemodynamics and outcome using CMR in 144 chronic kidney disease patients with estimated glomerular filtration rate <15 ml/min (110 on dialysis). Aortic distensibilty and volumetric arterial strain were calculated from cross sectional aortic volume and pulse pressure measured during the scan.</p> <p>Results</p> <p>Median follow up after the scan was 24 months. There were no significant differences in aortic distensibilty or aortic volumetric arterial strain between pre-dialysis and dialysis patients. Aortic distensibilty and volumetric arterial strain negatively correlated with age. Aortic distensibilty and volumetric arterial strain were lower in diabetics, patients with ischaemic heart disease and peripheral vascular disease. During follow up there were 20 deaths. Patients who died had lower aortic distensibilty than survivors. In a survival analysis, diabetes, systolic blood pressure and aortic distensibilty were independent predictors of mortality. There were 12 non-fatal cardiovascular events during follow up. Analysing the combined end point of death or a vascular event, diabetes, aortic distensibilty and volumetric arterial strain were predictors of events.</p> <p>Conclusion</p> <p>Deranged vascular function measured with CMR correlates with cardiovascular risk factors and predicts outcome. CMR measures of vascular function are potential targets for interventions to reduce cardiovascular risk.</p