Global Trends in Mineral Commodities for Advanced Technologies

The U.S. Geological Survey National Minerals Information Center (NMIC) is the U.S. Government agency tasked with the collection, analysis, and dissemination of information on the production, consumption, import, export, and other measures of the flows of non-fuel mineral commodities of importance to the U.S. economy and national security. The NMIC and its agency predecessors have maintained a database of this information, collected and published annually, dating back to the beginning of the twentieth century. Time series analysis of annual information from the NMIC provides the opportunity to identify trends in the supply chains of the minerals and metals which are increasingly in demand for advanced technologies. The identification of trends in data for net import reliance, country concentration of production, global demand, price volatility, and other measures, when combined with world governance indicators, can be used to focus attention on individual mineral commodities where supply chain restrictions may develop. Specific examples for U.S. net import reliance, global tantalum primary mining, and mineral criticality screening are presented to illustrate the utility of time series analysis of trends in mineral commodity supply and demand, the types of data required, and the limitations of currently available information.     

On Northern Hemisphere Wave Patterns Associated with Winter Rainfall Events in China

During extended winter(November–April),43% of the intraseasonal rainfall variability in China is explained by three spatial patterns of temporally coherent rainfall.These patterns were identified with empirical orthogonal teleconnection(EOT) analysis of observed 1982–2007 pentad rainfall anomalies and connected to midlatitude disturbances.However,examination of individual strong EOT events shows that there is substantial inter-event variability in their dynamical evolution,which implies that precursor patterns found in regressions cannot serve as useful predictors.To understand the physical nature and origins of the extratropical precursors,the EOT technique is applied to six simulations of the Met Office Unified Model at horizontal resolutions of 200–40 km,with and without air–sea coupling.All simulations reproduce the observed precursor patterns in regressions,indicating robust underlying dynamical processes.Further investigation into the dynamics associated with observed patterns shows that Rossby wave dynamics can explain the large inter-event variability.The results suggest that the apparently slowly evolving or quasi-stationary waves in regression analysis are a statistical amalgamation of more rapidly propagating waves with a variety of origins and properties.     

Updating land cover automatically based on change detection using satellite images: case study of national forests in Southern California

Observing dynamic change patterns and higher-order complexities from remotely sensed images is warranted, but the main challenges include image inconsistency, plant phenological differences, weather variations, and difficulties of incorporating natural conditions into automatic image processing. In this study, we proposed a new algorithm and demonstrated it by producing 2002–2008 and 2010 land-cover maps in heterogeneous Southern California based on an existing 2009 land-cover map. The new algorithm improves the baseline land-cover map quality by discarding potential bad land-cover pixels and dividing each land-cover type into several subclasses. Time series Landsat images were used to detect changed and unchanged areas between baseline year and target year t. Subsequently, for each individual year t, each pixel that was identified as unchanged inherited the baseline classification. Otherwise, each pixel in the changed areas was classified by a similar surrogate majority classifier. The demonstration results in Southern California showed that the land-cover temporal pattern captured the observed successional stages of the ecosystem very well. The accuracy assessment had an overall classification accuracies ranging from 81% to 86% and overall kappa coefficients ranging from 0.79 to 0.83.     

Comment on Rust et al.: Human–Carnivore Conflict in Namibia Is Not Simply About Black and White

Carnivore conservationists agree that addressing the socioeconomic needs of people is critical to human-carnivore conflict mitigation. We therefore welcome studies that encompass complex social and cultural factors that affect the severity of human-carnivore conflict on Namibian farmlands. However, we contend that the recent study by Rust et al. (2016 Rust, N. A., J. Tzanopoulos, T. Humle, and D. C. MacMillan. 2016. Why has human–carnivore conflict not been resolved in Namibia? Society &; Natural Resources 29 (9):1079–94. doi:10.1080/08941920.2016.1150544[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) was poorly designed, used inappropriate sampling methods, lacked quantitative information on their qualitative results, and ultimately produced unsupported conclusions about the role of historic apartheid and current racism in exacerbating human-carnivore conflict in Namibia. We outline our concerns regarding the methods used, and demonstrate that the conclusions drawn by Rust et al. were not supported by their data.     

Research Ethics,Trauma and Self-care: reflections on disaster geographies

In this Research Note, I reflect on researcher trauma in the discipline of geography, and explore ways to build a framework for researcher self-care by facilitating conversations about mental health in collaboration with Human Research Ethics Committees, Professional and Organisational Development Services and Workplace Health and Safety units.     

Constraining a Flow Model with Field Measurements to Assess Water Transit Time Through a Vadose Zone

The modeling of thick vadose zones is particularly challenging because of difficulties in collecting a variety of measured sediment properties, which are required for parameterizing the model. Some models rely on synthetic data, whereas others are simplified by running as homogeneous sediment domains and relying on a single set of sediment properties. Few studies have simulated flow processes through a thick vadose zone using real and comprehensive data sets comprising multiple measurements. Here, we develop a flow model for a 7-m-thick vadose zone. This model, combining the numerical codes CTRAN/W with SEEP/W, includes the measured sediment hydraulic properties of the investigated vadose zone and incorporates the actual climate and subsurface conditions of the study site (precipitations, water-table elevations, and stable isotope data). The model is calibrated by fitting the simulated and measured vertical profiles of water content. Our flow model calculates a transit time of 1 year for the travel of water through the 7-m vadose zone; this estimate matches stable isotope-based results obtained previously for this site. A homogeneous sediment domain flow model, which considers only a single set of sediment properties, produces a transit time that is approximately half the duration of that of the heterogeneous flow model. This difference highlights the importance of assuming heterogeneous material within models of thick vadose zones and testifies to the advantage gained when using real sediment hydraulic properties to parametrize a flow model.     

Cryptogam covers on sepulchral monuments and re-colonization of a marble surface after cleaning

Re-colonization of freshly cleaned surfaces by aeroterrestrial microbial communities is up to now poorly understood. Here, we present a comparative study addressing the composition of algal and fungal communities on a marble sculpture, based upon the analysis of 18S rRNA gene clone libraries from environmental samples. The samples were taken from a blackish and greenish biofilm cover before surface cleaning and 1 year after cleaning treatment, when traces of re-colonization became visible to the naked eye. The composition of the fungal community indicated clear differences between the old grown biofilm and the treated surface. While the former was dominated by the ascomycetes Rhinocladiella, Glyphium and Capnodiales, the black yeast Sarcinomyces was clearly dominant 1 year after cleaning, but could not be retrieved from the old grown black biofilm. The green algal community was dominated by different phylotypes of the lichen algae Trebouxia, as well as the cosmopolitan green algae Apatococcus and Stichococcus. No essential differences in the green algal community before and after cleaning could be observed.     

Impact of Geometric and Petrographic Characteristics on the Variability of LA Test Values for Railway Ballast

The Los Angeles test is one of the few mechanical test methods that provides information on the quality of railway ballast. However, the Los Angeles value is subject to large variability. Since important economic decisions depend on this value, the reasons for its variability are investigated. An extensive series of tests using four types of rock as well as an in-depth analysis of particle geometry and petrography are carried out. The impact of particle characteristics on the test results is investigated. The deviation of the petrographic composition within a given sample turns out to have a considerable impact on the Los Angeles test results, whereas the influence of the respective deviation of particle geometry is relatively small. The latter effect only comes into play in connection with petrographically homogeneous rock types. The distribution of the geometric features is similar in almost all of the rock types investigated. Due to the large deviation in particle shape and angularity, the sample mass of 10 kg (as provided in the standards EN 1097-2 and EN 13450) is not found to be representative. The necessary number of test repetitions in order to exclude the effect of deviation of particle geometry is estimated. The one result parameter according to the standard, the Los Angeles value, does not allow for discriminating between the amount of abrasion and the fragmentation occurring during the test. An additional result parameter for the estimation of the fragmentation rate is therefore proposed.