Evidence for a meteoritic origin of the September 15, 2007, Carancas crater

On September 15th, 2007, around 11:45 local time in Peru, near the Bolivian border, the atmospheric entry of a meteoroid produced bright lights in the sky and intense detonations. Soon after, a crater was discovered south of Lake Titicaca. These events have been detected by the Bolivian seismic network and two infrasound arrays operating for the Comprehensive Nuclear-Test-Ban Treaty Organization, situated at about 80 and 1620 km from the crater. The localization and origin time computed with the seismic records are consistent with the reported impact. The entry elevation and azimuthal angles of the trajectory are estimated from the observed signal time sequences and backazimuths. From the crater diameter and the airwave amplitudes, the kinetic energy, mass and explosive energy are calculated. Using the estimated velocity of the meteoroid and similarity criteria between orbital elements, an association with possible parent asteroids is attempted. The favorable setting of this event provides a unique opportunity to evaluate physical and kinematic parameters of the object that generated the first actual terrestrial meteorite impact seismically recorded

Characterization and inventory of contaminants in WAG 2 floodplain soils of White Oak Creek

A remedial investigation was conducted to determine the extent and type of contamination in the floodplain soils of Waste Area Grouping (WAG) 2, in conjunction with environmental restoration activities at the US Department of Energy (DOE) Oak Ridge Reservation (ORR). WAG 2 is located downstream from the main Oak Ridge National Laboratory (ORNL) plant area. As a result of past, present, and potential future releases of hazardous substances to the environment, the ORR was placed on the National Priorities List in December 1989. Sites on this list must be investigated to determine if remedial actions are possible. This report documents the findings of the remedial investigation of the WAG 2 floodplain soils by (1) presenting the characterization and inventory of contaminants, (2) comparing the walkover survey data to quantitative gamma-emitting radionuclide data, and (3) presenting an assessment of human health risk from exposure to these soils. Contaminant characterization results indicated that the primary contaminants in the WAG 2 floodplain are the gamma-emitting radionuclides {sup 137}Cs and {sup 60}Co, although cobalt activity levels are 1/25th or less than those of cesium. Inorganic contaminants discussed in this report were limited to those contributing significantly to human exposure: antimony, barium, chromium(IV), manganese, mercury, and nickel

Evaluation as a multi-stakeholder process : the Programme for Capacity and Theory Building for Universities and Research Centres in Endogenous Development (CAPTURED) in Bolivia, Ghana and India

An evaluation is a particular multi-stakeholder event during which different actors share and analyse results after several years. If the evaluation has a strong formative purpose the evaluation team is requested to facilitate a learning process involving all key actors. Especially evaluations that emphasise deeper learning have to be designed in such a way that different perspectives emerge and are appreciated in an interactive way. The present article reviews the results and methodological design of the evaluation of the Programme for Capacity and Theory Building for Universities and Research Centres in Endogenous Development (CAPTURED) in Universities and higher education centres in Bolivia, Ghana and India. The ambition of CAPTURED was to validate and integrate endogenous knowledge and values into education and research programmes. The three cases show how different stakeholders in three different context situations have interacted in higher education and research change processes. The evaluation provided an example of a mixed methods design that allowed for inclusion and appreciation of perspectives of different stakeholders. The evaluation facilitated a learning process engaging the various actors in joint analysis and formulation of shared conclusions and recommendations. Each evaluation team has to consider which set of methods is responding to the required domain and project context, and how the methods complement each other or can be adapted to the case. The design should deliver both quantitative as well as qualitative data that provide evidence about results as well as the stories and background what these results mean for different stakeholders. In this way the evaluation provided both summative evaluation (providing an assessment of results) as well as formative understanding (learning) what these results meant for different stakeholders. The case shows how an evaluation can be conducted as a facilitated process with different project stakeholders by applying mixed methods design to allow actors to learn from project results

High-resolution variability of dissolved and suspended organic matter in the Cape Verde Frontal Zone

21 pages, 8 figures, 4 tables.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)Distributions of dissolved (DOM) and suspended (POM) organic matter, and their chromophoric (CDOM) and fluorescent (FDOM) fractions, are investigated at high resolution (< 10 km) in the Cape Verde Frontal Zone (CVFZ) during fall 2017. In the epipelagic layer (< 200 m), meso- and submesoscale structures (meanders, eddies) captured by the high resolution sampling dictate the tight coupling between physical and biogeochemical parameters at the front. Remarkably, fluorescent humic-like substances show relatively high fluorescence intensities between 50 and 150 m, apparently not related to local mineralization processes. We hypothesize that it is due to the input of Sahara dust, which transports highly re-worked DOM with distinctive optical properties. In the mesopelagic layer (200-1500 m), our results suggest that DOM and POM mineralization occurs mainly during the transit of the water masses from the formation sites to the CVFZ. Therefore, most of the local mineralization seems to be due to fast-sinking POM produced in situ or imported from the Mauritanian upwelling. These local mineralization processes lead to the production of refractory CDOM, an empirical evidence of the microbial carbon pump mechanism. DOM released from these fast-sinking POM is the likely reason behind the observed columns of relatively high DOC surrounded by areas of lower concentration. DOM and POM dynamics in the CVFZ has turned out to be very complex, in parallel to the complexity of meso- and submesoscale structures present in the area. On top of this high resolution variability, the input of Sahara dust or the release of DOM from sinking particles have been hypothesized to explain the observed distributionsThis work was funded by Spanish National Science Plan research grants FERMIO (CTM2014–57334–JIN) and FLUXES (CTM2015-69392-C3), co–financed with FEDER funds, and e-IMPACT (PID2019-109084RB-C21 and –C22). RC, SV and NB were supported by predoctoral fellowships from the Spanish Ministry of Science and Innovation (BES-2016-076462, BES- 2016-079216 and BES-2016-077949). BF-C was supported by a Juan de la Cierva Formación fellowship (FJCI-641-2015-25712) and by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 834330 (SO-CUP). JA was partly supported by the project SUMMER (AMD-817806-5) from the European Union’s Horizon 2020 research and innovation programPeer reviewe

Assessing survival in widowers, and controls -A nationwide, six- to nine-year follow-up

To access full text version of this article. Please click on the hyperlink "View/open" at the bottom of this pageThe aim of this study was to assess if widowers had an increased mortality rate during the first 6 to 9 years after the death of their wife, compared initially to an age-matched control group and also compared to the general population of Iceland. The study base was comprised of all 371 men born in 1924-1969 who were widowed in Iceland in 1999-2001 and 357 controls, married men, who were matched by age and residence.The widowers and controls were followed through the years 2002-2007 using information from Statistics Iceland. Mortality rates were compared between the groups and also with the general population. The mortality rate comparisons were: study group vs. control group, on the one hand, and study group vs. general population on the other. Causes of death were also compared between widowers and their wives. A statistically significant increase in mortality in the widowers' group, compared to controls, was observed.Lifestyle-related factors could not be excluded as contributing to cause of death in these cases. Being a widower was related to an increased risk of death for at least 9 years after the death of their wife.Landspitali - National University Hospital in Reykjavik Iceland, Rannis, the Icelandic Centre for Research (provides assistance to Icelandic science & technology, Reykjavik, Iceland), Utfararstofa Islands (a funeral home, Reykjavik, Iceland), Swedish Cancer Society (Cancerfonden), Styrktarsjodur Lifsins samtaka um liknarmedferd (Palliative Care Association, Iceland), Utfarastofa Kirkjugardanna (a funeral home, Reykjavik, Iceland

Nationality and migration in modern Mexico

Scholarship on nationalism and the state has examined how immigration and nationality policy create boundaries of inclusion and exclusion. While a handful of countries of immigration have been analysed extensively, explanations of nationality law have not accounted adequately for countries of emigration. This paper's historical analysis of Mexican nationality law and its congressional debate demonstrates that the ways the state has defined nationality at different periods cannot be attributed simply to demographic migration patterns or legacies of past understandings of ethnic or state-territorial nationhood, according to the expectations of received theory. The literature's focus on geopolitically stronger countries of immigration obscures the critical effects of inter-state politics on nationality law in subordinate states. Mexico's nationality laws reflect its experiences as a geopolitically weak country of immigration, despite a net out-migration of its population

Evaluation of metal and radionuclide data from neutron activation and acid-digestion-based spectrometry analyses of background soils: Significance in environmental restoration

A faster, more cost-effective, and higher-quality data acquisition procedure for natural background-level metals and radionuclides in soils is needed for remedial investigations of contaminated sites. In this project, a total of 120 soil samples were collected from uncontaminated areas on and near the Oak Ridge Reservation. The samples were taken at three different depths and from three different geologic groups to establish background concentrations of metals and radionuclides. The objective of this presentation is to discuss the advantages and disadvantages of neutron activation analysis (NAA) compared with those of acid-digestion-based spectrometry (ADS) methods; the advantages and disadvantages were evaluated from Al, Sb, As, Cr, Co, Fe, Mg, Mn, Hg, K, Ag, {sup 232}Th, {sup 235}U, {sup 238}U, V, and Zn data. The ADS methods used for this project were inductively coupled plasma (ICP), ICP-mass spectrometry (ICP-MS), and alpha spectrometry. The scatter plots showed that the NAA results for As, Co, Fe, Mn, {sup 232}Th, and {sup 238}U are reasonably correlated with the results from the other analytical methods. Compared to NAA, however, the ADS methods underestimated Al, Cr, Mg, K, V, and Zn. The skew distributions were caused by incomplete dissolution of the analytes during acid digestion of the soil samples. Because of the high detection limits of the spectrometric methods, the NAA results and the ADS results for some elements, including Sb, Hg, and Ag, did not show a definite relationship. The NAA results were highly correlated with the alpha spectrometry results for {sup 232}Th and {sup 238}U but poorly correlated for {sup 235}U, probably because of a larger counting error associated with the lower activity of the isotope. The NAA methods, including the delayed neutron counting method, were far superior techniques for quantifying background levels of radionuclides ({sup 232}Th, {sup 235}U, and {sup 238}U) and metals (Al, Cr, Mg, K, V, and Zn) in soils