A New Single-Filter Method for Analyzing Coastal Aerosol Production and Links to Meteorology

Aerosols are known to influence the climate system in a range of ways; they affect radiation budgets, cloud formation and circulation patterns, and contribute to local biogeochemical cycling and ecology. Despite this recognized role for marine aerosol, however, recent research has emphasized the impact of global climate change on coastal environments rather than the other way around. This occurs in part because most methods for sampling marine aerosol are expensive and studies tend to occur only on specialized marine stations and ocean-crossing research vessels. This project tests a new method for aerosol sampling, specifically designed for use in local studies of coastal environments and costing little to set up. It also reports the results of a pilot study in Alderney (Channel Islands) where changes in both aerosol abundance and aerosol composition, including fractionation effects, were observed using the new method and linked to local meteorological conditions.     

Mortgage Foreclosures,Race, and Postrecession Lending

This article examines the effect of high foreclosure rates on postrecession lending. Our hypothesis is that high neighborhood foreclosure rates will have a significant and positive effect on the likelihood of mortgage loan denial. In a case study on Toledo, Ohio, we explore the role of foreclosure activity, race, and racial disparities in lending practices and how they differ across neighborhoods. Our results suggest that applicants in high-foreclosure neighborhoods have a greater likelihood of loan denial (ceteris paribus). We also find that minority applicants face a higher probability of loan denial in high-foreclosure minority neighborhoods. Overall, the results depict highly variable lending practices where race seems to make a difference albeit in a small subset of neighborhoods deeply affected by the foreclosure crisis. There is also some indication of a chilling effect on minority loan applicants in Toledo during the postrecession period. Key Words: foreclosure, logistic regression, mortgage lending, neighborhood contingency, race discrimination.     

Preliminary report on a dinosaur tracksite from Lower Cretaceous strata in Mount Lebanon

A dinosaur tracksite was discovered in Batha on the side of the road from Harissa to Ghosta (Keserwan, Lebanon). About ten trackways are exposed at the top of two beds of Lower Cretaceous limestones over an area of approximately 1000 m². These footprints were probably made by at least two dinosaur species, Sauropoda and either Theropoda or Ornithopoda. The site, which is the first record from Lebanon, should be protected to allow further scientific investigations.     

Reliable Determination of Ge in Solid Environmental Samples Using a Chemical Preparation Procedure Developed for Si Isotopes and ICP‐MS Analysis

Germanium (Ge) exists at trace levels in the Earth's crust and is a powerful geochemical tracer of the silicon (Si) cycle. This study proposes a simple and reliable method for determining Ge contents in environmental samples using ICP‐MS. As Si and Ge have very similar chemical properties, we investigated the applicability of the chemical preparation procedure developed for Si isotopes for the determination of Ge in environmental samples. Advantages of this procedure are as follows: (a) efficient removal of the matrix and main interferences affecting Ge determinations by ICP‐MS, (b) a low limit of detection (6 ng l^?1), (c) relative repeatability of approximately 3% obtained on ⁷⁴Ge and (d) robustness and accuracy based on agreement within errors with the published Ge values for rock reference materials (BHVO‐2, AGV‐2 and BCR‐2). This procedure allowed revision of the Ge values of three soil reference materials (1.67 ± 0.09 μg g^?1, 2.41 ± 0.18 μg g^?1, 1.89 ± 0.10 μg g^?1 for GBW 07401, GBW 07404 and GBW 07407, respectively) and proposal of a value for the plant reference material ERM‐CD281 (70 ± 3 μg g^?1). This method provides a convenient procedure for determining Ge mass fractions in environmental samples and opens the possibility of coupling two tracers of the Si biogeochemical cycle with a single measurement procedure.     

Detecting communities with the multi-scale Louvain method: robustness test on the metropolitan area of Brussels

Detecting communities in large networks has become a common practice in socio-spatial analyses and has led to the development of numerous dedicated mathematical algorithms. Nowadays, however, researchers face a deluge of data and algorithms, and great care must be taken regarding methodological questions such as the values of the parameters and the geographical characteristics of the data. We aim here at testing the sensitivity of multi-scale modularity optimized by the Louvain method to the value of the resolution parameter (introduced by Reichardt and Bornholdt (Phys Rev Lett 93(21):218701, 2004.  https://doi.org/10.1103/PhysRevLett.93.218701) and controlling the size of the communities) and to a number of spatial issues such as the inclusion of internal loops and the delineation of the study area. We compare the community structures with those found by another well-known community detection algorithm (Infomap), and we further interpret the final results in terms of urban geography. Sensitivity analyses are conducted for commuting movements in and around Brussels. Results reveal slight effects of spatial issues (inclusion of the internal loops, definition of the study area) on the partition into job basins, while the resolution parameter plays a major role in the final results and their interpretation in terms of urban geography. Community detection methods seem to reveal a surprisingly strong spatial effect of commuting patterns: Similar partitions are obtained with different methods. This paper highlights the advantages and sensitivities of the multi-scale Louvain method and more particularly of defining communities of places. Despite these sensitivities, the method proves to be a valuable tool for geographers and planners.     

Trading more food: Implications for land use,greenhouse gas emissions,and the food system

The volume of agricultural trade increased by more than ten times throughout the past six decades and is likely to continue with high rates in the future. Thereby, it largely affects environment and climate. We analyse future trade scenarios covering the period of 2005–2045 by evaluating economic and environmental effects using the global land-use model MAgPIE (“Model of Agricultural Production and its Impact on the Environment”). This is the first trade study using spatially explicit mapping of land use patterns and greenhouse gas emissions. We focus on three scenarios: the reference scenario fixes current trade patterns, the policy scenario follows a historically derived liberalisation pathway, and the liberalisation scenario assumes a path, which ends with full trade liberalisation in 2045.Further trade liberalisation leads to lower global costs of food. Regions with comparative advantages like Latin America for cereals and oil crops and China for livestock products will export more. In contrast, regions like the Middle East, North Africa, and South Asia face the highest increases of imports. Deforestation, mainly in Latin America, leads to significant amounts of additional carbon emissions due to trade liberalisation. Non-CO₂ emissions will mostly shift to China due to comparative advantages in livestock production and rising livestock demand in the region. Overall, further trade liberalisation leads to higher economic benefits at the expense of environment and climate, if no other regulations are put in place.     

Comparing the fractality of European urban neighbourhoods: do national contexts matter?

The objective of this paper is to show that morphological similarities between built-up urban surfaces are greater across borders than within cities in Europe: living, architectural and planning trends are international. The spatial arrangement of built-up areas is analysed here by means of fractal indices using a set of 97 town sections selected from 18 European urban agglomerations. The fractal dimension is estimated by correlation techniques. Results confirm that morphological similarities are higher across countries/cities than within. Moreover, two types of fractal laws are considered: one uses the basic fractal scaling law; the other introduces a prefactor a that is often called a “form factor” in the fractal literature. Differences in the results obtained by both laws are explained empirically as well as theoretically, and suggestions are made for further measurements.     

Evaluation of the WAMME model surface fluxes using results from the AMMA land-surface model intercomparison project

The West African monsoon (WAM) circulation and intensity have been shown to be influenced by the land surface in numerous numerical studies using regional scale and global scale atmospheric climate models (RCMs and GCMs, respectively) over the last several decades. The atmosphere–land surface interactions are modulated by the magnitude of the north–south gradient of the low level moist static energy, which is highly correlated with the steep latitudinal gradients of the vegetation characteristics and coverage, land use, and soil properties over this zone. The African Multidisciplinary Monsoon Analysis (AMMA) has organised comprehensive activities in data collection and modelling to further investigate the significance land–atmosphere feedbacks. Surface energy fluxes simulated by an ensemble of land surface models from AMMA Land-surface Model Intercomparison Project (ALMIP) have been used as a proxy for the best estimate of the “real world” values in order to evaluate GCM and RCM simulations under the auspices of the West African Monsoon Modelling Experiment (WAMME) project, since such large-scale observations do not exist. The ALMIP models have been forced in off-line mode using forcing based on a mixture of satellite, observational, and numerical weather prediction data. The ALMIP models were found to agree well over the region where land–atmosphere coupling is deemed to be most important (notably the Sahel), with a high signal to noise ratio (generally from 0.7 to 0.9) in the ensemble and a inter-model coefficient of variation between 5 and 15%. Most of the WAMME models simulated spatially averaged net radiation values over West Africa which were consistent with the ALMIP estimates, however, the partitioning of this energy between sensible and latent heat fluxes was significantly different: WAMME models tended to simulate larger (by nearly a factor of two) monthly latent heat fluxes than ALMIP. This results due to a positive precipitation bias in the WAMME models and a northward displacement of the monsoon in most of the GCMs and RCMs. Another key feature not found in the WAMME models is peak seasonal latent heat fluxes during the monsoon retreat (approximately a month after the peak precipitation rates) from soil water stores. This is likely related to the WAMME northward bias of the latent heat flux gradient during the WAM onset.     

Role of natural nanoparticles on the speciation of Ni in andosols of la Reunion

Andosols on the island of Réunion have high nickel (Ni) concentrations due to the natural pedo-geochemical background. Enhanced knowledge of Ni speciation is necessary to predict the bioavailability and potential toxicity of this element. Ni speciation in these andosols, marked by the presence of high amounts of natural aluminosilicate nanoparticles, was investigated in two complementary systems: (i) In a soil sample—densimetric fractionation was first performed in order to separate the potential bearing phases, prior to Ni speciation characterization. (ii) In a synthetic sample—Ni reactivity with synthetic aluminosilicate nanoparticle analogs were studied. In both cases, Ni speciation was determined using X-ray absorption spectroscopy (XAS). The results revealed that Ni had the same local environment in both systems (natural and synthetic systems), and Ni was chemically linked to natural short-range ordered aluminosilicates or analogs. This complex represented about 75% of the total Ni in the studied soil.