BGS Library : a world of information

Over the last 175 years the British Geological Survey Library has grown and developed into one of the world's major earth science libraries. We have extensive collections of books, maps, journals and BGS publications. We also hold special collections of British geological photographs and archive material, chiefly the historical archives of the BGS. Published material is acquired by exchange with overseas surveys and institutes as well as by purchase. In the past our collections have been enhanced by the incorporation of other collections such as the extensive holdings of the former Overseas Geological Surveys

Hiding in the Shadows II: Collisional Dust as Exoplanet Markers

Observations of the youngest planets ($\sim$1-10 Myr for a transitional disk) will increase the accuracy of our planet formation models. Unfortunately, observations of such planets are challenging and time-consuming to undertake even in ideal circumstances. Therefore, we propose the determination of a set of markers that can pre-select promising exoplanet-hosting candidate disks. To this end, N-body simulations were conducted to investigate the effect of an embedded Jupiter mass planet on the dynamics of the surrounding planetesimal disk and the resulting creation of second generation collisional dust. We use a new collision model that allows fragmentation and erosion of planetesimals, and dust-sized fragments are simulated in a post process step including non-gravitational forces due to stellar radiation and a gaseous protoplanetary disk. Synthetic images from our numerical simulations show a bright double ring at 850 $\mu$m for a low eccentricity planet, whereas a high eccentricity planet would produce a characteristic inner ring with asymmetries in the disk. In the presence of first generation primordial dust these markers would be difficult to detect far from the orbit of the embedded planet, but would be detectable inside a gap of planetary origin in a transitional disk.Comment: Accepted for publication in Ap

Giraffe translocation population viability analysis

Most populations of giraffes have declined in recent decades, leading to the recent IUCN decision to upgrade the species to Vulnerable status, and some subspecies to Endangered. Translocations have been used as a conservation tool to re-introduce giraffes to previously occupied areas or establish new populations, but guidelines for founding populations are lacking. To provide general guidelines for translocation projects regarding feasibility, we simulated various scenarios of translocated giraffe populations to identify viable age and sex distributions of founding populations using population viability analysis (PVA) implemented in Vortex software. We explored the parameter space for demography and the genetic load, examining how variation in founding numbers and sex ratios affected 100 yr probability of population extinction and genetic diversity. We found that even very small numbers of founders (N ≤ 10 females) can appear to be successful in the first decades due to transient positive population growth, but with moderate population growth rate and moderate genetic load, long-term population viability (probability of extinction 95% genetic diversity of the source population in an isolated population, 50 females and 5 males are recommended to compose the founding population. Sensitivity analyses revealed first-year survival and reproductive rate were the simulation parameters with the greatest proportional influence on probability of extinction and genetic diversity. These simulations highlight important considerations for translocation success and data gaps including true genetic load in wild giraffe populations

Explaining the variability of WD 1145+017 with simulations of asteroid tidal disruption

Post-main-sequence planetary science has been galvanised by the striking variability, depth and shape of the photometric transit curves due to objects orbiting white dwarf WD 1145+017, a star which also hosts a dusty debris disc and circumstellar gas, and displays strong metal atmospheric pollution. However, the physical properties of the likely asteroid which is discharging disintegrating fragments remain largely unconstrained from the observations. This process has not yet been modelled numerically. Here, we use the N-body code PKDGRAV to compute dissipation properties for asteroids of different spins, densities, masses, and eccentricities. We simulate both homogeneous and differentiated asteroids, for up to two years, and find that the disruption timescale is strongly dependent on density and eccentricity, but weakly dependent on mass and spin. We find that primarily rocky differentiated bodies with moderate (~3-4 g/cm^3) bulk densities on near-circular (e <~ 0.1) orbits can remain intact while occasionally shedding mass from their mantles. These results suggest that the asteroid orbiting WD 1145+017 is differentiated, resides just outside of the Roche radius for bulk density but just inside the Roche radius for mantle density, and is more akin physically to an asteroid like Vesta instead of one like Itokawa.Comment: Accepted in MNRAS. Movies here!: http://www.star.bris.ac.uk/pcarter/WD1145_asteroid_disruption

Group-based positive psychotherapy for people living with acquired brain injury: a protocol for a feasibility study

BackgroundAcquired brain injury (ABI) and other chronic conditions are placing unprecedented pressure on healthcare systems. In the UK, 1.3 million people live with the effects of brain injury, costing the UK economy approximately £15 billion per year. As a result, there is an urgent need to adapt existing healthcare delivery to meet increasing current and future demands. A focus on wellbeing may provide an innovative opportunity to reduce the pressure on healthcare services while also supporting patients to live more meaningful lives. The overarching aims of the study are as follows: (1) evaluate the feasibility of conducting a positive psychotherapy intervention for individuals with ABI and (2) ascertain under what conditions such an intervention would merit a fully powered randomised controlled trial (RCT) compared to a standard control group (TAU).Methods and analysisA randomised, two-arm feasibility trial involving allocation of patients to either a treatment group (positive psychotherapy) or control group (treatment as usual) group, according to a 1:1 ratio. A total of 60 participants at three sites will be recruited including 20 participants at each site. Assessments will be conducted at baseline, on completion of the 8-week intervention and 3 months following completion. These will include a range of questionnaire-based measures, psychophysiology and qualitative outcomes focusing on feasibility outcomes and participant experience. This study has been approved by the Wales Research Ethics Committee (IRAS project ID: 271,251, REC reference: 19/WA/0336).DiscussionThis study will be the first to examine the feasibility of an innovative, holistic positive psychotherapy intervention for people living with ABI, focused on individual, collective and planetary wellbeing, and will enable us to determine whether to proceed to a full randomised controlled trial

Explaining the variability of WD 1145+017 with simulations of asteroid tidal disruption

Post-main-sequence planetary science has been galvanised by the striking variability, depth and shape of the photometric transit curves due to objects orbiting white dwarf WD 1145+017, a star which also hosts a dusty debris disc and circumstellar gas, and displays strong metal atmospheric pollution. However, the physical properties of the likely asteroid which is discharging disintegrating fragments remain largely unconstrained from the observations. This process has not yet been modelled numerically. Here, we use the N-body code PKDGRAV to compute dissipation properties for asteroids of different spins, densities, masses, and eccentricities. We simulate both homogeneous and differentiated asteroids, for up to two years, and find that the disruption timescale is strongly dependent on density and eccentricity, but weakly dependent on mass and spin. We find that primarily rocky differentiated bodies with moderate (∼ 3−4 g/cm3 ) bulk densities on near-circular (e . 0.1) orbits can remain intact while occasionally shedding mass from their mantles. These results suggest that the asteroid orbiting WD 1145+017 is differentiated, resides just outside of the Roche radius for bulk density but just inside the Roche radius for mantle density, and is more akin physically to an asteroid like Vesta instead of one like Itokawa