Gate-to-Gate Life-Cycle Inventory of Softwood Lumber Production

To perform a life-cycle analysis, a life-cycle inventory is needed. Data from surveys of manufacturers are presented for the energy and materials required to produce 1.623 m3 (1 mbf) of planed, dry, dimension lumber from logs in the western and southern U.S. In the West and South, 53 and 41% of the log volume (3.05 and 3.92 m3) leaves the mill as planed, dry dimension lumber, respectively. A much greater portion of the energy used for production in the South is produced on site from wood fuels. CO2 emissions were greater in the South because of the wood fuel, 574 kg versus 419 kg per 1.623 m3 produced

Nest monitoring does not affect nesting success of Whinchats Saxicola rubetra

It is important to assess the effect that research activities may have on animals in the wild, especially when key parameters, such as breeding success, could potentially be influenced by observer activity. For birds, some studies have suggested that nest monitoring can increase the chances of nest failure due to predation, whereas others suggest that human nest visits may actually deter mammalian predators. Nest monitoring visits can also influence breeding success more indirectly by altering parental provisioning behaviour. Here, the influence of monitoring activities on nest success was examined in a ground-nesting grassland bird, the Whinchat Saxicola rubetra. During the egg phase, a sample of nests were not visited between the initial finding event and the estimated hatching date; instead, the nest status was assessed at a distance. Daily survival rates (DSR) for these nests were compared with that of nests visited every 2 days. During the nestling phase, the effects of observer nest visits on parental provisioning behaviour were determined. Nest visits were found not to affect egg DSR significantly, and parental provisioning was disrupted for a maximum of 20 min (0.52% of the nestling period) following an observer visit. Given the variation in response to nest visits across species, we suggest that consideration should be given to observer impact in all studies where predation risk is high. Here, we illustrate a method for researchers to assess the impact of their nest visits to ensure they are not biasing estimates of breeding success

Pseudo-Ductile Behaviour in Fibre Reinforced Thermoplastic Angle-ply Composites

Pseudo-ductile behaviour has previously been demonstrated in a [±45n]s carbon fibre composite via fibre rotation. To further develop the pseudo-ductile response, the high strain properties of the matrix should be considered to avoid strain localisation and potentially exploit strain-hardening in an amorphous thermoplastic matrix. For the first time, polycarbonate, a high strain-to-failure matrix is utilised in a pseudo-ductile composite design and compared to a high performance thermoset fibre composite containing an epoxy resin. The use of polycarbonate leads to enhanced pseudo-ductile strain (49%), longitudinal strength (24%) and apparent in-plane shear strength (26%), albeit with a reduction in elastic modulus (26%), shear chord modulus (22%) and yield strength (26%)

Diffusion-mediated HEI10 coarsening can explain meiotic crossover positioning in Arabidopsis.

In most organisms, the number and distribution of crossovers that occur during meiosis are tightly controlled. All chromosomes must receive at least one 'obligatory crossover' and crossovers are prevented from occurring near one another by 'crossover interference'. However, the mechanistic basis of this phenomenon of crossover interference has remained mostly mysterious. Using quantitative super-resolution cytogenetics and mathematical modelling, we investigate crossover positioning in the Arabidopsis thaliana wild-type, an over-expressor of the conserved E3 ligase HEI10, and a hei10 heterozygous line. We show that crossover positions can be explained by a predictive, diffusion-mediated coarsening model, in which large, approximately evenly-spaced HEI10 foci grow at the expense of smaller, closely-spaced clusters. We propose this coarsening process explains many aspects of Arabidopsis crossover positioning, including crossover interference. Consistent with this model, we also demonstrate that crossover positioning can be predictably modified in vivo simply by altering HEI10 dosage, with higher and lower dosage leading to weaker and stronger crossover interference, respectively. As HEI10 is a conserved member of the RING finger protein family that functions in the interference-sensitive pathway for crossover formation, we anticipate that similar mechanisms may regulate crossover positioning in diverse eukaryotes

Sexual selection for both diversity and repetition in birdsong

From fiddler crabs to humans, animals perform repetitive displays showing neuromotor skill and vigour. Consistent repetition of identical notes (vocal consistency) facilitates the assessment of neuromotor skills and is important in communication in birds. Most birdsong research has focused on song diversity as a signal of individual quality, which seems contradictory as repetition is extremely common in most species. Here we show that consistent repetition within songs is positively correlated with reproductive success in male blue tits (Cyanistes caeruleus). A playback experiment shows that females are sexually aroused by male songs with high levels of vocal consistency, which also peaks seasonally during the fertile period of the female, supporting the role of vocal consistency in mate choice. Male vocal consistency also increases with subsequent repetitions of the same song type (a warm-up effect) which conflicts with the fact that females habituate to repeated song, showing decreased arousal. Importantly, we find that switching song types elicits significant dishabituation within the playback, supporting the habituation hypothesis as an evolutionary mechanism driving song diversity in birds. An optimal balance between repetition and diversity may explain the singing style of many bird species and displays of other animals

A limit to sustained performance constrains trill length in birdsong

In birds, song performance determines the outcome of contests over crucial resources. We hypothesized that 1) sustained performance is limited within song, resulting in a performance decline towards the end and 2) the impact of song length is compromised if performance declines. To test these hypotheses, we analyzed the songs of 597 bird species (26 families) and conducted a playback experiment on blue tits (Cyanistes caeruleus). Our multi-species analysis showed that song performance declines after sustained singing, supporting our hypothesis. If the performance decline is determined by individual attributes (i.e., physical condition), our results explain how trill length can honestly signal quality. Our experiment showed that longer trills of high performance elicited a stronger response during territorial interactions. However, long trills that declined in performance elicited a weaker response than short, high-performance trills. A trade-off between the duration and performance quality of a motor display can be an important aspect in communication across taxa

Sound properties affect measurement of vocal consistency in birdsong: validation of the spectrogram cross correlation method (SPCC)

In songbirds, singing with precision (vocal consistency) has been proposed to reflect whole-organism performance. Vocal consistency is measured using spectrogram cross correlation (SPCC) to assess the acoustic similarity between subsequent renditions of the same note. To quantify how SPCC is sensitive to the acoustic discrepancies found in birdsong, we created a set of 40 000 synthetic sounds that were designed based on the songs of 345 species. This set included 10 000 reference sounds and 30 000 inexact variants with quantified differences in frequency, bandwidth, or duration with respect to the reference sounds. We found that SPCC is sensitive to acoustic discrepancies within the natural range of vocal consistency, supporting the use of this method as a tool to assess vocal consistency in songbirds. Importantly, the sensitivity of SPCC was significantly affected by the bandwidth of sounds. The predictions derived from the analysis of synthetic sounds were then validated using 954 song recordings from 345 species (20 families). Based on psychoacoustic studies from birds and humans, we propose that the sensitivity of SPCC to acoustic discrepancies mirrors a perceptual bias in sound discrimination. Nevertheless, we suggest the tool be used with care, since sound bandwidth varies considerably between singing styles and therefore, SPCC scores may not be comparable

Metabolic syndrome is associated with increased breast cancer risk: a systematic review with meta-analysis

Background. Although individual metabolic risk factors are reported to be associated with breast cancer risk, controversy surrounds risk of breast cancer from metabolic syndrome (MS). We report the first systematic review and meta-analysis of the association between MS and breast cancer risk in all adult females. Methods. Studies were retrieved by searching four electronic reference databases [PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, and ProQuest through June 30, 2012] and cross-referencing retrieved articles. Eligible for inclusion were longitudinal studies reporting associations between MS and breast cancer risk among females aged 18 years and older. Relative risks and 95% confidence intervals were calculated for each study and pooled using random-effects models. Publication bias was assessed quantitatively (Trim and Fill) and qualitatively (funnel plots). Heterogeneity was examined using and 2 statistics. Results. Representing nine independent cohorts and 97,277 adult females, eight studies met the inclusion criteria. A modest, positive association was observed between MS and breast cancer risk (RR: 1.47, 95% CI, 1.15-1.87; = 3.13; = 0.002; = 26.28, = 0.001; 2 = 69.55%). No publication bias was observed. Conclusions. MS is associated with increased breast cancer risk in adult women

Using exomarkers to assess mitochondrial reactive species in vivo

Background: The ability to measure the concentrations of small damaging and signalling molecules such as reactive oxygen species (ROS) in vivo is essential to understanding their biological roles. While a range of methods can be applied to in vitro systems, measuring the levels and relative changes in reactive species in vivo is challenging. Scope of review: One approach towards achieving this goal is the use of exomarkers. In this, exogenous probe compounds are administered to the intact organism and are then transformed by the reactive molecules in vivo to produce a diagnostic exomarker. The exomarker and the precursor probe can be analysed ex vivo to infer the identity and amounts of the reactive species present in vivo. This is akin to the measurement of biomarkers produced by the interaction of reactive species with endogenous biomolecules. Major conclusions and general significance: Our laboratories have developed mitochondria-targeted probes that generate exomarkers that can be analysed ex vivo by mass spectrometry to assess levels of reactive species within mitochondria in vivo. We have used one of these compounds, MitoB, to infer the levels of mitochondrial hydrogen peroxide within flies and mice. Here we describe the development of MitoB and expand on this example to discuss how better probes and exomarkers can be developed. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn. Abbreviations: EPR, electron paramagnetic resonance; GFP, green fluorescent protein; 4-HNE, 4-hydroxynonenal; MitoB, 3-(dihydroxyboronyl)benzyltriphenylphosphonium bromide; MitoP, (3-hydroxybenzyl)triphenylphosphonium bromide; ROS, reactive oxygen species; SOD, superoxide dismutase; TPMP, methyltriphenylphosphonium; TPP, triphenylphosphonium catio

The XMM Cluster Survey: The interplay between the brightest cluster galaxy and the intra-cluster medium via AGN feedback

Using a sample of 123 X-ray clusters and groups drawn from the XMM-Cluster Survey first data release, we investigate the interplay between the brightest cluster galaxy (BCG), its black hole, and the intra-cluster/group medium (ICM). It appears that for groups and clusters with a BCG likely to host significant AGN feedback, gas cooling dominates in those with Tx > 2 keV while AGN feedback dominates below. This may be understood through the sub-unity exponent found in the scaling relation we derive between the BCG mass and cluster mass over the halo mass range 10^13 < M500 < 10^15Msol and the lack of correlation between radio luminosity and cluster mass, such that BCG AGN in groups can have relatively more energetic influence on the ICM. The Lx - Tx relation for systems with the most massive BCGs, or those with BCGs co-located with the peak of the ICM emission, is steeper than that for those with the least massive and most offset, which instead follows self-similarity. This is evidence that a combination of central gas cooling and powerful, well fuelled AGN causes the departure of the ICM from pure gravitational heating, with the steepened relation crossing self-similarity at Tx = 2 keV. Importantly, regardless of their black hole mass, BCGs are more likely to host radio-loud AGN if they are in a massive cluster (Tx > 2 keV) and again co-located with an effective fuel supply of dense, cooling gas. This demonstrates that the most massive black holes appear to know more about their host cluster than they do about their host galaxy. The results lead us to propose a physically motivated, empirical definition of 'cluster' and 'group', delineated at 2 keV.Comment: Accepted for publication in MNRAS - replaced to match corrected proo