Valuing local perspectives on invasive species management: Moving beyond the ecosystem service-disservice dichotomy

This paper uses the concept of ecosystem disservices to explore and understand how rapid environmental change associated with an invasive plant species is framed and understood by different stakeholders. Through a focus on narratives, the paper explores how socially-differentiated populations understand the causes and consequences of a plant invasion and express preferences for often contrasting management interventions. The research design uses a workshop format to instigate a series of conversations with socially-differentiated groups of people to explore how people perceive and respond to the impact of Prosopis juliflora (a species of mesquite) in the drylands of Ethiopia. The results show that preferences for interventions differs by age, gender, location and livelihood and also by primary and secondary stakeholder. Different sets of values underpin people’s views and these contribute to the variation in the preference for different management interventions. To understand complex issues associated with alien invasive species, we find that the dichotomy between ecosystem services and disservices is artificial and call for a more dynamic and graduated view of ecosystem outputs. More practically, our research shows that P. juliflora management options need wider consideration of socially-differentiated implications and trade-offs and this requires greater efforts to engage with primary stakeholders

Floods and health in Gambella region, Ethiopia: a qualitative assessment of the strengths and weaknesses of coping mechanisms

BACKGROUND: Floods are the most frequent and devastating type of natural disaster worldwide, causing unprecedented deaths, diseases, and destruction of property and crops. Flooding has a greater impact in developing countries due to lack of sufficient disaster management structures and a lack of economic resources. OBJECTIVE: This study was conducted with the aim of contributing to the knowledge base of development strategies that reduce flood-related health risks in developing countries. The study focused particularly on assessing the flood risks and health-related issues in the Gambella region of Ethiopia; with the intent of producing relevant information to assist with the improvements in the efficacy of the current flood coping strategies in the region. METHODS: Data were gathered through interviews with 14 officers from different government and non-governmental organizations and a questionnaire survey given to 35 flood victims in Itang woreda. A qualitative approach was applied and the data were analyzed using content analysis. RESULTS: It was found that flooding is a common problem in Gambella region. The findings also indicate that the flood frequency and magnitude has increased rapidly during the last decade. The increase in floods was driven mainly by climate change and changes in land use, specifically deforestation. The reported main impacts of flooding on human health in Gambella region were deaths, injuries, and diseases such as malaria and diarrhea. Another notable consequence of flooding was crop destruction and subsequent malnutrition. CONCLUSIONS: Three weaknesses that were identified in the current coping strategies for flood-related health impacts in Gambella region were a lack of flood-specific policy, absence of risk assessment, and weak institutional capacity. This study recommends new policy approaches that will increase the effectiveness of the current flood coping strategies to sustainably address the impact of flooding on human health

Do ultrafast exciton-polaron decoherence dynamics govern photocarrier generation efficiencies in polymer solar cells?

All-organic-based photovoltaic solar cells have attracted considerable attention because of their low-cost processing and short energy payback time. In such systems the primary dissociation of an optical excitation into a pair of photocarriers has been recently shown to be extremely rapid and efficient, but the physical reason for this remains unclear. Here, two-dimensional photocurrent excitation spectroscopy, a novel non-linear optical spectroscopy, is used to probe the ultrafast coherent decay of photoexcitations into charge-producing states in a polymer:fullerene based solar cell. The two-dimensional photocurrent spectra are interpreted by introducing a theoretical model for the description of the coupling of the electronic states of the system to an external environment and to the applied laser fields. The experimental data show no cross-peaks in the two-dimensional photocurrent spectra, as predicted by the model for coherence times between the exciton and the photocurrent producing states of 20\,fs or less

Lessons Learned from the Flight Unit Testing of the Near Earth Asteroid Scout Flight System

The Near Earth Asteroid Scout flight mission is set to launch on the maiden voyage of the Space Launch System as a secondary payload. The spacecraft will be jettisoned in cis-lunar space and embark on an ambitious 2.5 year mission to image an asteroid. The spacecraft is uniquely equipped with an 85m2 solar sail as the main propulsion system. The monolithic sail system is designed to package within a 6U volume for launch and then deploy during flight. The NEA Scout team has presented in the past to the International Symposium on Solar Sailing topics related to the engineering development unit and design efforts to achieve flight hardware build. This paper will focus on the lessons learned from building and testing the NEA Scout flight system. Focus will be on the mechanical, software, and electrical interfaces as well as preparation for subsystem environmental tests, including thermal vacuum. Due to the unique design of the spacecraft, the solar sail subsystem was required to be located in the center of the spacecraft. This requirement lead to design challenges such as designing and accommodating critical cable harnesses to run through the center of the sail subsystem, packaging and deployment design of the sail subsystem, and integrated testing efforts through an avionics test bed to verify and validate a complete system architecture

Numerical modelling of Auriga's Wheel - a new ring galaxy

We model the formation of Auriga's Wheel - a recently discovered collisional ring galaxy. Auriga's Wheel has a number of interesting features including a bridge of stars linking the neighbouring elliptical to the ring galaxy, and evidence for components of expansion and rotation within the ring. Using N-body/SPH modelling, we study collisions between an elliptical galaxy and a late-type disk galaxy. A near direct collision, with a mildy inclined disk, is found to reasonably reproduce the general system morphology ~50 Myr following the collision. The collision must have a relatively low velocity (initially ~150 km s^{-1}) in order to form the observed bridge, and simultaneously match the galaxies separation. Our best-match model suggests the total disk galaxy is ~5 times more massive than the elliptical. We find that the velocity of expansion of the ring is sensitive to the mass of the elliptical, while insensitive to the encounter velocity. We evolve our simulation beyond the current epoch to study the future destiny of the galaxy pair. In our model, the nucleus moves further away from the plane of the ring in the direction of the stellar bridge. The nucleus eventually merges with the elliptical galaxy ~100 Myr after the present time. The ring continues to expand for ~200 Myr before collapsing back. The low initial relative velocity of the two galaxies will eventually result in a complete merger.Comment: Accepted to MNRAS, March 9th, 2012. 17 pages, 16 figures, no table

The association of genetic predisposition to depressive symptoms with non-suicidal and suicidal self-Injuries

Non-suicidal and suicidal self-injury are very destructive, yet surprisingly common behaviours. Depressed mood is a major risk factor for non-suicidal self-injury (NSSI), suicidal ideation and suicide attempts. We conducted a genetic risk prediction study to examine the polygenic overlap of depressive symptoms with lifetime NSSI, suicidal ideation, and suicide attempts in a sample of 6237 Australian adult twins and their family members (3740 females, mean age\ua0=\ua042.4\ua0years). Polygenic risk scores for depressive symptoms significantly predicted suicidal ideation, and some predictive ability was found for suicide attempts; the polygenic risk scores explained a significant amount of variance in suicidal ideation (lowest p\ua0=\ua00.008, explained variance ranging from 0.10 to 0.16\ua0%) and, less consistently, in suicide attempts (lowest p\ua0=\ua00.04, explained variance ranging from 0.12 to 0.23\ua0%). Polygenic risk scores did not significantly predict NSSI. Results highlight that individuals genetically predisposed to depression are also more likely to experience suicidal ideation/behaviour, whereas we found no evidence that this is also the case for NSSI