Discrimination of different volcanic rock units by magnetic properties — geothermal field at Reykjanes peninsula (SW-Iceland)

The geothermal field at Reykjanes peninsula is located at the boundary where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland. The geothermal field coincides with a magnetic low in the aeromagnetic anomaly map and is situated within a dense NE–SW fissure and fault zone. Surface geology is characterized by different historic fissure eruptions (youngest from 1226AD), shield lava (12.5–14.5 ka) and intercalated pillow basalt–hyaloclastite ridges probably formed during the last glacial episode (14.5–20 ka). During a field magnetic study in the vicinity of the geothermal field in summer 2005 different volcanic rock units have been sampled to correlate rock magnetic and magneto-mineralogical properties with magnetic field intensity. Additionally, measurements on a dense dolerite intrusion, recovered from the RN–19 borehole (2245–2248m depth) in May 2005 within the frame of IDDP, should shed light on the influence of crustal rocks on the total magnetic field intensity. Generally, the natural remanent magnetization and magnetic susceptibility, measured on rock specimen, is high, ranging between 2.5 and 33.6Am−1 and 2–37 ×10−3 SI, respectively...conferenc

Century-scale trends and seasonality in pH and temperature for shallow zones of the Bering Sea

No records exist to evaluate long-term pH dynamics in high-latitude oceans, which have the greatest probability of rapid acidification from anthropogenic CO2 emissions. We reconstructed both seasonal variability and anthropogenic change in seawater pH and temperature by using laser ablation high-resolution 2D images of stable boron isotopes (δ11B) on a long-lived coralline alga that grew continuously through the 20th century. Analyses focused on four multiannual growth segments. We show a long-term decline of 0.08 ± 0.01 pH units between the end of the 19th and 20th century, which is consistent with atmospheric CO2 records. Additionally, a strong seasonal cycle (∼0.22 pH units) is observed and interpreted as episodic annual pH increases caused by the consumption of CO2 during strong algal (kelp) growth in spring and summer. The rate of acidification intensifies from –0.006 ± 0.007 pH units per decade (between 1920s and 1960s) to –0.019 ± 0.009 pH units per decade (between 1960s and 1990s), and the episodic pH increases show a continuous shift to earlier times of the year throughout the centennial record. This is indicative of ecosystem shifts in shallow water algal productivity in this high-latitude habitat resulting from warming and acidification

Sandbox:Creating and analysing synthetic sediment sections with R

Past environmental information is typically inferred from proxy data contained in accretionary sediments. The validity of proxy data and analysis workflows are usually assumed implicitly, with systematic tests and uncertainty estimates restricted to modern analogue studies or reduced-complexity case studies. However, a more generic and consistent approach to exploring the validity and variability of proxy functions would be to translate a sediment section into a model scenario: a “virtual twin”. Here, we introduce a conceptual framework and numerical tool set that allows the definition and analysis of synthetic sediment sections. The R package sandbox describes arbitrary stratigraphically consistent deposits by depth-dependent rules and grain-specific parameters, allowing full scalability and flexibility. Virtual samples can be taken, resulting in discrete grain mixtures with defined parameters. These samples can be virtually prepared and analysed, for example, to test hypotheses. We illustrate the concept of sandbox, explain how a sediment section can be mapped into the model and explore geochronological research questions related to the effects of sample geometry and grain-size-specific age inheritance. We summarise further application scenarios of the model framework, relevant for but not restricted to the broader geochronological community.CREDit - Chronological REference Datasets and Sites (CREDit) towards improved accuracy and precision in luminescence-based chronologie

Flux et crues singulières d'un petit cours d'eau andin ou les effets pervers de l'urbanisation

Sur un petit bassin de haute montagne (4000 m), situé dans les Andes à proximité de La Paz, la canalisation des "rios" en vue de gagner des terrains urbanisables, n'a guère modifié, en termes de bilan annuel, les régimes hydrologiques mais a eu des conséquences inattendues sur leur comportement en crue. Au delà d'un certain débit, bien inférieur au débit maximum décennal, apparaissent des vagues, parfois plus hautes que le canal, qui déferlent à près de 10 m/s, endommageant sur leur passage ponts et parois de l'ouvrage, et provoquant d'importants débordements en zone urbaine. Plus en amont, dans le lit naturel, l'écoulement demeure stable. Plusieurs hypothèses sont avancées pour expliquer ce phénomène. (Résumé d'auteur

Sub-daily Statistical Downscaling of Meteorological Variables Using Neural Networks

AbstractA new open source neural network temporal downscaling model is described and tested using CRU-NCEP reanal ysis and CCSM3 climate model output. We downscaled multiple meteorological variables in tandem from monthly to sub-daily time steps while also retaining consistent correlations between variables. We found that our feed forward, error backpropagation approach produced synthetic 6 hourly meteorology with biases no greater than 0.6% across all variables and variance that was accurate within 1% for all variables except atmospheric pressure, wind speed, and precipitation. Correlations between downscaled output and the expected (original) monthly means exceeded 0.99 for all variables, which indicates that this approach would work well for generating atmospheric forcing data consistent with mass and energy conserved GCM output. Our neural network approach performed well for variables that had correlations to other variables of about 0.3 and better and its skill was increased by downscaling multiple correlated variables together. Poor replication of precipitation intensity however required further post-processing in order to obtain the expected probability distribution. The concurrence of precipitation events with expected changes in sub ordinate variables (e.g., less incident shortwave radiation during precipitation events) were nearly as consistent in the downscaled data as in the training data with probabilities that differed by no more than 6%. Our downscaling approach requires training data at the target time step and relies on a weak assumption that climate variability in the extrapolated data is similar to variability in the training data

Integrated on-chip mass spectrometry reaction monitoring in microfluidic devices containing porous polymer monolithic columns

Chip-based microfluidics enable the seamless integration of different functions into single devices. Here, we present microfluidic chips containing porous polymer monolithic columns as a means to facilitate chemical transformations as well as both downstream chromatographic separation and mass spectrometric analysis. Rapid liquid phase lithography prototyping creates the multifunctional device economically

Working together: Expanding the availability of naloxone for peer administration to prevent opioid overdose deaths in the Australian Capital Territory and beyond

Issue. Since the mid-1990s, there have been calls to make naloxone, a prescription-only medicine in many countries, available to heroin and other opioid users and their peers and family members to prevent overdose deaths. Context. In Australia there were calls for a trial of peer naloxone in 2000, yet at the end of that year, heroin availability and harm rapidly declined, and a trial did not proceed. In other countries, a number of peer naloxone programs have been successfully implemented. Although a controlled trial had not been conducted, evidence of program implementation demonstrated that trained injecting drug-using peers and others could successfully administer naloxone to reverse heroin overdose, with few, if any, adverse effects. Approach.In 2009 Australian drug researchers advocated the broader availability of naloxone for peer administration in cases of opioid overdose. Industrious local advocacy and program development work by a number of stakeholders, notably by the Canberra Alliance for Harm Minimisation and Advocacy, a drug user organisation, contributed to the rollout of Australia’s first prescription naloxone program in the Australian Capital Territory (ACT). Over the subsequent 18 months, prescription naloxone programs were commenced in four other Australian states. Implications. The development of Australia’s first take-home naloxone program in the ACT has been an ‘ice-breaker’ for development of other Australian programs. Issues to be addressed to facilitate future scale-up of naloxone programs concern scheduling and cost, legal protections for lay administration,prescribing as a barrier to scale-up; intranasal administration, administration by service providers and collaboration between stakeholders

Scaling Contagious Disturbance: A Spatially-Implicit Dynamic Model

Spatial processes often drive ecosystem processes, biogeochemical cycles, and land-atmosphere feedbacks at the landscape-scale. Climate-sensitive disturbances, such as fire, land-use change, pests, and pathogens, often spread contagiously across the landscape. While the climate-change implications of these factors are often discussed, none of these processes are incorporated into earth system models as contagious disturbances because they occur at a spatial scale well below model resolution. Here we present a novel second-order spatially-implicit scheme for representing the size distribution of spatially contagious disturbances. We demonstrate a means for dynamically evolving spatial adjacency through time in response to disturbance. Our scheme shows that contagious disturbance types can be characterized as a function of their size and edge-to-interior ratio. This emergent disturbance characterization allows for description of disturbance across scales. This scheme lays the ground for a more realistic global-scale exploration of how spatially-complex disturbances interact with climate-change drivers, and forwards theoretical understanding of spatial and temporal evolution of disturbance