Present day serpentinization in New Caledonia,Oman and Yugoslavia

Geochemical evidence for modern low-temperature serpentinization has been found in three new localities. Apparently the low-temperature reactions are a common mode of formation of the lizardite-chrysotile and brucite assemblage. Possibly the ¹⁸O content of serpentine formed at low temperatures is in part inherited from the pyroxene and olivine.     

The Bear Brook Watershed in Maine: Multi-decadal whole-watershed experimental acidification

The Bear Brook Watershed in Maine (BBWM) is a long-term research site established to study the response of forest ecosystem function to environmental disturbances of chronic acidic deposition and ecosystem nitrogen enrichment. Starting in 1989, the West Bear (treated) watershed received bimonthly applications of ammonium sulfate [(NH₄)₂SO₄] fertilizer from above the canopy, whereas East Bear (reference) received ambient deposition. The treatments were stopped in 2016, marking the beginning of the recovery phase. Research at the site has focused on soils, streams, and vegetation. Here, we describe data collected over three decades at the BBWM—input and stream output nutrient fluxes, quantitative soil pits and soil chemistry, and soil temperature and moisture.     

Skills in Professional Geography: An Assessment of Workforce Needs and Expectations

This study compares the skills of professional geographers and the needs of employer organizations across major sectors of the U.S. workforce. Following a series of focus groups, two surveys were developed to explore: (1) the extent to which specific skills were performed by geographers in different professional positions, and (2) the value of and anticipated demand for those skills from the perspective of employers. Overall, respondents in the focus groups and both surveys emphasized the need for general skills ranging from time management and writing ability to information management and computer literacy. Employers also cited many geographic skills as being vital for enhancing the work of professionals in all types of organizations. Competency in field methods, the ability to work across disciplinary boundaries, and spatial thinking were three skill areas that characterized the work of geographic professionals irrespective of specialty.     

Spatial distribution of lead and lead isotopes in soil B-horizon, forest-floor humus, grass (Avenella flexuosa) and spruce (Picea abies) needles across the Czech Republic

Lead concentrations were determined in samples of soil B-horizon (N = 258), forest-floor humus (O-horizon, N = 259), grass (Avenella flexuosa, N = 251) and spruce (Picea abies, N = 253) needles (2nd year) collected at the same locations evenly spread over the territory of the Czech Republic at an average density of 1 site/300 km². Median Pb concentrations differ widely in the four materials: soil B-horizon: 27 mg/kg (3.3-220 mg/kg), humus: 78 mg/kg (19-1863 mg/kg), grass: 0.37 mg/kg (0.08-8 mg/kg) and spruce needles: 0.23 mg/kg (0.07-3 mg/kg). In the Pb distribution maps for humus, grass and spruce a number of well-known Pb-contamination sources are indicated by unusually high concentrations (e.g., the Pb smelter at Pribram, the metallurgical industry in the NE of the Czech Republic and along the Polish border, as well as the metallurgical industry in Upper Silesia and Europe’s largest coal-fired power plant at Bogatynia, Poland). The ratio ²⁰⁶Pb/²⁰⁷Pb was determined in all four materials. The median value of the ²⁰⁶Pb/²⁰⁷Pb isotope ratio in the soil B-horizon is 1.184 (variation: 1.145-1.337). In both humus and grass the median value for the ²⁰⁶Pb/²⁰⁷Pb isotope ratio is 1.162 (variation: 1.130-1.182), in spruce needles the median ratio is 1.159 (variation: 1.116-1.186). In humus, grass and spruce needles the known contamination sources are all marked by higher ²⁰⁶Pb/²⁰⁷Pb isotope ratios in the maps. Furthermore, the soil B-horizon, humus, grass and spruce needles show distinctly different spatial distribution patterns of the ²⁰⁶Pb/²⁰⁷Pb isotope ratios. The B-horizon does not provide a viable background value for metal concentrations in the O-horizon or plant materials. None of the maps provides evidence for the importance of traffic-related emissions for the observed isotope ratios at the scale of the Czech Republic.     

European space agency’s strategic contribution to seismology

The impacts of disaster events such as earthquakes on economic and human lives are increasing every year, in particular due to the growing urbanization. Until recently, stakeholders involved in disaster risk management focused their efforts mainly on the response phase, immediately after the crisis. Following the recommendations of several recent studies and in order to minimize the increasing impacts of natural disasters, decision-makers and major stakeholders have showed an increasing interest in mitigation activities. Earth Observation (EO) data from space could bring a significant added value to the various phases of the seismic risk management cycle from the mitigation and preparedness phases. Space agencies need to better contribute to the management of geohazards in response to the growing request from the community of users (e.g. seismologists, insurance companies, urban planners). To foster the use of EO remote sensing data, satellite data providers have to take the appropriate measures to remove the policy and technical barriers related to the data access. They have also to increase the awareness of the community of users on the potential benefits that could be gained from the use of EO satellite data. This paper will provide examples of areas where EO remote sensing data from space could bring an added value to the current management of risks and crisis related to earthquakes. Then, the paper will describe the strategic measures undertaken by the European Space Agency in an international framework, to foster the use of satellite data by the various relevant stakeholders.     

Attenuation in the uppermost inner core from PKP recordings at African seismological stations

The attenuation factor Q_P at the top of the inner core is evaluated by using the amplitude spectral ratio of PKPdf and PKPbc phases observed at African stations (BGCA mostly), from strong deep earthquakes in the Pacific Ocean area. The maximum depth of penetration of the PKPdf phase into the inner core (IC) is roughly 377 km, and the sampled region of IC is centered beneath the Southern Indian Ocean. The derived mean value of Q_P is 249 ± 31 (95% confidence level) in the frequency range 0.2–2 Hz, where no frequency dependence of attenuation has been reliably observed. By using Student’s t-test, we show that the value is statistically significantly different (with a probability greater than 95%) from other mean values of Q derived by using the same method, for both the western (180 °W to 40 °E) and eastern (40 °E to 180 °E) hemispheres of the IC. The decrease of Q with the radius of the turning point (denoted by r^TP), according to Q_P = 840 − 0.62 r^TP, has a moderate statistical support (the R-squared value is 38%). A slightly increase of Q as a function of the angle of the PKPdf path within the inner core with respect to the Earth’s spin axis is observed, in agreement with various investigations performed in the time domain. However, the value of the anisotropy, if any, is suggested to be around 3%.     

The 2dF Galaxy Redshift Survey: galaxy luminosity functions per spectral type

We calculate the optical b _J luminosity function (LF) of the 2dF Galaxy Redshift Survey (2dFGRS) for different subsets defined by their spectral properties. These spectrally selected subsets are defined using a new parameter, η , which is a linear combination of the first two projections derived from a Principal Component Analysis. This parameter η identifies the average emission- and absorption-line strength in the galaxy rest frame spectrum, and hence is a useful indicator of the present star formation. We use a total of 75 000 galaxies in our calculations, chosen from a sample of high signal-to-noise ratio, low-redshift galaxies observed before 2001 January. We find that there is a systematic steepening of the faint-end slope ( α ) as one moves from passive  ( α =-0.54)  to active  ( α =-1.50)  star-forming galaxies, and that there is also a corresponding faintening of the rest frame characteristic magnitude   M *-5 log₁₀( h )  (from −19.6 to −19.2). We also show that the Schechter function provides a poor fit to the quiescent (Type 1) LF for very faint galaxies  [ M _{b J}-5 log₁₀( h )  fainter than −16.0], perhaps suggesting the presence of a significant dwarf population. The LFs presented here give a precise confirmation of the trends seen previously in a much smaller preliminary 2dFGRS sample, and in other surveys. We also present a new procedure for determining self-consistent k -corrections, and investigate possible fibre-aperture biases.