Cultural selection drives the evolution of human communication systems

Human communication systems evolve culturally, but the evolutionary mechanisms that drive this evolution are not well understood. Against a baseline that communication variants spread in a population following neutral evolutionary dynamics (also known as drift models), we tested the role of two cultural selection models: coordination- and content-biased. We constructed a parametrized mixed probabilistic model of the spread of communicative variants in four 8-person laboratory micro-societies engaged in a simple communication game. We found that selectionist models, working in combination, explain the majority of the empirical data. The best-fitting parameter setting includes an egocentric bias and a content bias, suggesting that participants retained their own previously used communicative variants unless they encountered a superior (content-biased) variant, in which case it was adopted. This novel pattern of results suggests that (i) a theory of the cultural evolution of human communication systems must integrate selectionist models and (ii) human communication systems are functionally adaptive complex systems

No Evidence for Orbital Loop Currents in Charge Ordered YBa2_2Cu3_3O6+x_{6+x} from Polarized Neutron Diffraction

It has been proposed that the pseudogap state of underdoped cuprate superconductors may be due to a transition to a phase which has circulating currents within each unit cell. Here, we use polarized neutron diffraction to search for the corresponding orbital moments in two samples of underdoped YBa$_2$Cu$_3$O$_{6+x}$ with doping levels $p=0.104$ and 0.123. In contrast to some other reports using polarized neutrons, but in agreement with nuclear magnetic resonance and muon spin rotation measurements, we find no evidence for the appearance of magnetic order below 300 K. Thus, our experiment suggests that such order is not an intrinsic property of high-quality cuprate superconductor single crystals. Our results provide an upper bound for a possible orbital loop moment which depends on the pattern of currents within the unit cell. For example, for the CC-$\theta_{II}$ pattern proposed by Varma, we find that the ordered moment per current loop is less than 0.013 $\mu_B$ for $p=0.104$.Comment: Comments in arXiv:1710.08173v1 fully addresse

The effect of GSM-like ELF radiation on the alpha band of the human resting EEG

Mobile phone handsets such as those operating in the GSM network emit extremely low frequency electromagnetic fields ranging from DC to at least 40 kHz. As a subpart of an extended protocol, the influence of these fields on the human resting EEG has been investigated in a fully counter balanced, double blind, cross-over design study that recruited 72 healthy volunteers. A decrease in the alpha frequency band was observed during the 20 minutes of ELF exposure in the exposed hemisphere only. This result suggests that ELF fields as emitted from GSM handsets during the DTX mode may have an effect on the resting alpha band of the human EEG

'Pest' and resource: A legal history of Australia's kangaroos

This paper presents an investigation into the legal history of Australias kangaroos. It aims to provide a detailed analysis of how the law and policy governing the killing of kangaroos has evolved over time in response to changing public perceptions. This history begins with the pre-European period and traces the impact of European colonisation, early growth of the commercial kangaroo industry, and the increased role of science and regulation upon kangaroos. The paper critiques the historical designation of kangaroos as `pests that need to be `managed and argues that such an approach is inconsistent with current scientific understanding. As this `pest status has fallen in importance there has been a shift in regulatory goals from damage mitigation to resource utilisation, although government planning and policy continue to cite damage mitigation alongside objectives to maintain viable populations and a sustainable and commercially viable industry. While the kangaroo industrys current focus is upon the `sustainable use of wildlife, the history of attitudes towards kangaroos as `pests is so deeply and widely entrenched that it is impossible for the industry to meet welfare standards. The article concludes that the commercial kangaroo industry does not have any clearly defined policy benefit and should be reassessed to take greater account of the impact it has on ecosystems and kangaroo welfar

Improving Cosmological Distance Measurements by Reconstruction of the Baryon Acoustic Peak

The baryon acoustic oscillations are a promising route to the precision measure of the cosmological distance scale and hence the measurement of the time evolution of dark energy. We show that the non-linear degradation of the acoustic signature in the correlations of low-redshift galaxies is a correctable process. By suitable reconstruction of the linear density field, one can sharpen the acoustic peak in the correlation function or, equivalently, restore the higher harmonics of the oscillations in the power spectrum. With this, one can achieve better measurements of the acoustic scale for a given survey volume. Reconstruction is particularly effective at low redshift, where the non-linearities are worse but where the dark energy density is highest. At z=0.3, we find that one can reduce the sample variance error bar on the acoustic scale by at least a factor of 2 and in principle by nearly a factor of 4. We discuss the significant implications our results have for the design of galaxy surveys aimed at measuring the distance scale through the acoustic peak.Comment: 5 pages, LaTeX. Submitted to the Astrophysical Journa

Exploring and adjusting for potential learning effects in ROLARR: a randomised controlled trial comparing robotic-assisted vs. standard laparoscopic surgery for rectal cancer resection

Background: Commonly in surgical randomised controlled trials (RCT) the experimental treatment is a relatively new technique which the surgeons may still be learning, while the control is a well-established standard. This can lead to biased comparisons between treatments. In this paper we discuss the implementation of approaches for addressing this issue in the ROLARR trial, and points of consideration for future surgical trials. Methods: ROLARR was an international, randomised, parallel-group trial comparing robotic vs. laparoscopic surgery for the curative treatment of rectal cancer. The primary endpoint was conversion to open surgery (binary). A surgeon inclusion criterion mandating a minimum level of experience in each technique was incorporated. Additionally, surgeon self-reported data were collected periodically throughout the trial to capture the level of experience of every participating surgeon. Multi-level logistic regression adjusting for operating surgeon as a random effect is used to estimate the odds ratio for conversion to open surgery between the treatment groups. We present and contrast the results from the primary analysis, which did not account for learning effects, and a sensitivity analysis which did. Results: The primary analysis yields an estimated odds ratio (robotic/laparoscopic) of 0.614 (95% CI 0.311, 1.211; p = 0.16), providing insufficient evidence to conclude superiority of robotic surgery compared to laparoscopic in terms of the risk of conversion to open. The sensitivity analysis reveals that while participating surgeons in ROLARR were expert at laparoscopic surgery, some, if not all, were still learning robotic surgery. The treatment-effect odds ratio decreases by a factor of 0.341 (95% CI 0.121, 0.960; p = 0.042) per unit increase in log-number of previous robotic operations performed by the operating surgeon. The odds ratio for a patient whose operating surgeon has the mean experience level in ROLARR – 152.46 previous laparoscopic, 67.93 previous robotic operations – is 0.40 (95% CI 0.168, 0.953; p = 0.039). Conclusions: In this paper we have demonstrated the implementation of approaches for accounting for learning in a practical example of a surgery RCT analysis. The results demonstrate the value of implementing such approaches, since we have shown that without them the ROLARR analysis would indeed have been confounded by the learning effects

Warm-Hot Gas in and around the Milky Way: Detection and Implications of OVII Absorption toward LMC X-3

X-ray absorption lines of highly-ionized species such as OVII at about zero redshift have been firmly detected in the spectra of several active galactic nuclei. However, the location of the absorbing gas remains a subject of debate. To separate the Galactic and extragalactic contributions to the absorption, we have obtained Chandra LETG-HRC and FUSE observations of the black hole X-ray binary LMC X--3. A joint analysis of the detected OVII and Ne IX Kalpha lines, together with the non-detection of the OVII Kbeta and OVIII Kalpha lines, gives the measurements of the temperature, velocity dispersion, and hot oxygen column density. The X-ray data also allow us to place a 95% confidence lower limit to the Ne/O ratio as 0.14. The OVII line centroid and its relative shift from the Galactic OI Kalpha absorption line, detected in the same observations, are inconsistent with the systemic velocity of LMC X--3 ($+310 {\rm km s^{-1}}$). The far-UV spectrum shows OVI absorption at Galactic velocities, but no OVI absorption is detected at the LMC velocity at $> 3\sigma$ significance. Both the nonthermal broadening and the decreasing scale height with the increasing ionization state further suggest an origin of the highly-ionized gas in a supernova-driven galactic fountain. In addition, we estimate the warm and hot electron column densities from our detected OVII Kalpha line in the LMC X--3 X-ray spectra and from the dispersion measure of a pulsar in the LMC vicinity. We then infer the O/H ratio of the gas to be $\gtrsim 8 \times 10^{-5}$, consistent with the chemically-enriched galactic fountain scenario. We conclude that the Galactic hot interstellar medium should in general substantially contribute to zero-redshift X-ray absorption lines in extragalactic sources.Comment: 11 pages, accepted for publication in Ap

The Reactome BioMart

Reactome is an open source, expert-authored, manually curated and peer-reviewed database of reactions, pathways and biological processes. We provide an intuitive web-based user interface to pathway knowledge and a suite of data analysis tools. The Reactome BioMart provides biologists and bioinformaticians with a single web interface for performing simple or elaborate queries of the Reactome database, aggregating data from different sources and providing an opportunity to integrate experimental and computational results with information relating to biological pathways. Database URL: http://www.reactome.org