Are there prehistoric shell middens on Rottwest Island?

In August 1973 a number of different types of shell bed were observed at Rottnest Island. The most massive of these were seen around the lakes at the eastern end of the island and there is no doubt that these are natural marine shell beds. However elsewhere shelly deposits were seen whose origin we could not determine with certainty. A number of midden like lenses of shell were exposed in road sections, particularly along the north side of the island. All of these deposits displayed some of the characteristics of Aboriginal shell middens

A Bayesian statistical model is able to predict target-by-target selection behaviour in a human foraging task

Funding: This research was funded by the Economic and Social Research Council grant number ES/S016120/1 to A.D.F.C and A.R.H. Acknowledgments: The authors would like to thank all the researchers who publicly shared their data.Peer reviewedPostprintPublisher PD

Wild snakes harbor West Nile virus

West Nile virus (WNV) has a complex eco-epidemiology with birds acting as reservoirs and hosts for the virus. Less well understood is the role of reptiles, especially in wild populations. The goal of our study was to determine whether a wild population of snakes in Pennsylvania harbored WNV. Six species of snakes were orally sampled in the summer of 2013 and were tested for the presence of WNV viral RNA using RT-PCR. Two Eastern Garter Snakes, Thamnophis sirtalis sirtalis tested positive for viral RNA (2/123, 1.62%). These results indicate a possible role for snakes in the complex transmission cycle of WNV

Primordial Magnetic Fields via Spontaneous Breaking of Lorentz Invariance

Spontaneous breaking of Lorentz invariance compatible with observational limits may realistically take place in the context of string theories, possibly endowing the photon with a mass. In this process the conformal symmetry of the electromagnetic action is broken allowing for the possibility of generating large scale ($\sim Mpc$) magnetic fields within inflationary scenarios. We show that for reheating temperatures safe from the point of view of the gravitino and moduli problem, T_{RH} \laq 10^{9} GeV for $m_{3/2} \approx 1 TeV$, the strength of the generated seed fields is, in our mechanism, consistent with amplification by the galactic dynamo processes and can be even as large as to explain the observed galactic magnetic fields through the collapse of protogalactic clouds.Comment: Final version to appear in Physics Letters

Solar Flares and Coronal Mass Ejections: A Statistically Determined Flare Flux-CME Mass Correlation

In an effort to examine the relationship between flare flux and corresponding CME mass, we temporally and spatially correlate all X-ray flares and CMEs in the LASCO and GOES archives from 1996 to 2006. We cross-reference 6,733 CMEs having well-measured masses against 12,050 X-ray flares having position information as determined from their optical counterparts. For a given flare, we search in time for CMEs which occur 10-80 minutes afterward, and we further require the flare and CME to occur within +/-45 degrees in position angle on the solar disk. There are 826 CME/flare pairs which fit these criteria. Comparing the flare fluxes with CME masses of these paired events, we find CME mass increases with flare flux, following an approximately log-linear, broken relationship: in the limit of lower flare fluxes, log(CME mass)~0.68*log(flare flux), and in the limit of higher flare fluxes, log(CME mass)~0.33*log(flare flux). We show that this broken power-law, and in particular the flatter slope at higher flare fluxes, may be due to an observational bias against CMEs associated with the most energetic flares: halo CMEs. Correcting for this bias yields a single power-law relationship of the form log(CME mass)~0.70*log(flare flux). This function describes the relationship between CME mass and flare flux over at least 3 dex in flare flux, from ~10^-7 to 10^-4 W m^-2.Comment: 28 pages, 16 figures, accepted to Solar Physic

Overview of the SME: Implications and Phenomenology of Lorentz Violation

The Standard Model Extension (SME) provides the most general observer-independent field theoretical framework for investigations of Lorentz violation. The SME lagrangian by definition contains all Lorentz-violating interaction terms that can be written as observer scalars and that involve particle fields in the Standard Model and gravitational fields in a generalized theory of gravity. This includes all possible terms that could arise from a process of spontaneous Lorentz violation in the context of a more fundamental theory, as well as terms that explicitly break Lorentz symmetry. An overview of the SME is presented, including its motivations and construction. Some of the theoretical issues arising in the case of spontaneous Lorentz violation are discussed, including the question of what happens to the Nambu-Goldstone modes when Lorentz symmetry is spontaneously violated and whether a Higgs mechanism can occur. A minimal version of the SME in flat Minkowski spacetime that maintains gauge invariance and power-counting renormalizability is used to search for leading-order signals of Lorentz violation. Recent Lorentz tests in QED systems are examined, including experiments with photons, particle and atomic experiments, proposed experiments in space and experiments with a spin-polarized torsion pendulum.Comment: 40 pages, Talk presented at Special Relativity: Will it Survive the Next 100 Years? Potsdam, Germany, February, 200

Probing Lorentz and CPT violation with space-based experiments

Space-based experiments offer sensitivity to numerous unmeasured effects involving Lorentz and CPT violation. We provide a classification of clock sensitivities and present explicit expressions for time variations arising in such experiments from nonzero coefficients in the Lorentz- and CPT-violating Standard-Model Extension.Comment: 15 page

Post-traumatic stress disorder symptoms and mental health over time among low-income women at increased risk of HIV in the U.S

Women living in poverty suffer more post-traumatic stress disorder (PTSD) symptoms than do members of the general population; however we know little about factors associated with changes in their PTSD symptoms over time. Using data from HPTN 064, a cohort of women from low-income, high-HIV-prevalence communities across six eastern states (n=1,860), we assessed the prevalence of and changes in PTSD symptoms over 12 months and the effect of potential predictors on symptom acquisition and remission (via the Primary Care-PTSD symptoms scale). Forty-three percent screened positive for PTSD symptoms. Those reporting food insecurity, ongoing abuse, depressive symptoms, or binge drinking were more likely to acquire PTSD symptoms. Those with ongoing abuse or depressive symptoms were less likely to experience PTSD symptom remission. Findings suggest a need to integrate programs to reduce abuse, depression, and economic hardship with those that address sexual health risks among women living in low- income, high- HIVprevalence neighborhoods

CPT, T, and Lorentz Violation in Neutral-Meson Oscillations

Tests of CPT and Lorentz symmetry using neutral-meson oscillations are studied within a formalism that allows for indirect CPT and T violation of arbitrary size and is independent of phase conventions. The analysis is particularly appropriate for studies of CPT and T violation in oscillations of the heavy neutral mesons D, B_d, and B_s. The general Lorentz- and CPT-breaking standard-model extension is used to derive an expression for the parameter for CPT violation. It varies in a prescribed way with the magnitude and orientation of the meson momentum and consequently also with sidereal time. Decay probabilities are presented for both uncorrelated and correlated mesons, and some implications for experiments are discussed.Comment: 11 pages, references added, accepted in Physical Review