Photon path-length distribution function (I)

The determination of the photon path-length distribution function (PLDF) for the case of linearly anisotropic (Rocard) scattering in a semi-infinite plane-parallel homogeneous atmosphere using the Piessens-Huysmans method is described in detail. It has been shown that in this case the PLDF may have a minimum at small path-lengths — a feature which is never encountered in isotropic scattering. The respective regions with minima in the (µ, )-plane have been sorted out. As a rule, the average path-length in the case of the forward/backward Rocard scattering is larger/smaller than that in the isotropic case. The precise average path-lengths for a number of parameters are shown in Table I.     

Upstream waves and field line resonances: simultaneous presence and alternation in Pc3 pulsation events

Based on a detailed study of Pc3 events at an array between L = 1.5 and 3 in Central Europe, the authors found quick changes between upstream waves (UW, i.e. pulsation directly driven by UW) and field line resonance (FLR, i.e. azimuthal oscillations of geomagnetic field lines). The alternation of the two types is especially characteristic (and the UW part stronger) if the interplanetary magnetic field (IMF) is highly variable. Events due to field line resonance may have a structure consisting of multiple lines with frequencies differing by about 10%, corresponding to neighbouring shells of field lines separated by about 100 km at the surface. This coincides with previous findings (about 10% at a meridional distance of 80 km). The frequency of the UW type is well correlated with the frequency of waves in the interplanetary medium. Additionally, there are signals of unidentified origin which also seem to be influenced by IMF.     

Processes in soils and paleosoils

We determined the quantitative mineralogical compositions of various grain size fractions of soil samples that were collected from 10-cm depth intervals. Our results show that the grain size distribution curve of a given mineral is related to the mineral's origin and can be used as a source of information when soil-forming processes are studied.     

Quaternary tectonics in a passive margin: Marajó Island,northern Brazil

Marajó Island is located in a passive continental margin that evolved from rifting associated with the opening of the Equatorial South Atlantic Ocean in the Late Jurassic/Early Cretaceous period. This study, based on remote sensing integrated with sedimentology, as well as subsurface and seismographic data available from the literature, allows discussion of the significance of tectonics during the Quaternary history of marginal basins. Results show that eastern Marajó Island contains channels with evidence of tectonic control. Mapping of straight channels defined four main groups of lineaments (i.e. NNE–SSW, NE–SW, NW–SE and E–W) that parallel main normal and strike‐slip fault zones recorded for the Amazon region. Additionally, sedimentological studies of late Quaternary and Holocene deposits indicate numerous ductile and brittle structures within stratigraphic horizons bounded by undeformed strata, related to seismogenic deformation during or shortly after sediment deposition. This conclusion is consistent with subsurface Bouguer mapping suggestive of eastern Marajó Island being still part of the Marajó graben system, where important fault reactivation is recorded up to the Quaternary. Together with the recognition of several phases of fault reactivation, these data suggest that faults developed in association with rift basins might remain active in passive margins, imposing important control on development of depositional systems. Copyright © 2007 John Wiley & Sons, Ltd.     

Quality assessment of benthic macroinvertebrates under the scope of WFD using BAT, the Benthic Assessment Tool

Assessing the health of ecosystems has become a focal point among researchers worldwide. Recently, the European Water Framework Directive intensified the development of approaches to assess ecosystems’ ecological quality. The Benthic Assessment Tool (BAT) is a multimetric approach to evaluate condition of subtidal soft bottom macroinvertebrates of coastal and transitional waters. The effects of anthropogenic disturbances on benthic macroinvertebrate communities, from 1990 to 2006, allowed testing BAT performance in Mondego estuary (Portugal). The method was able to detect decrease on ecological quality, induced essentially by eutrophication and physical disturbances, and follow communities’ subsequent recovery. It evidenced, nevertheless, some limitations associated with the unstable nature of estuaries. The ecological classification of key species in the community and the balance expected between ecological groups of estuarine communities had great influence in the final ecological assessment. Shortcomings of the method were discussed in the light of its suitability for assessing transitional waters’ condition.     

The role of primary nonuniformity of mountain massifs in the reconstruction of tectonic stresses according to geological indicators

Features of the distribution of planes with traces of tectonic dislocations on gliding planes are examined, and the local stress conditions are restored on them, according to O.I. Gushchenko’s method [1979]. Most of the tectonic stresses were determined in the rock-crystal-bearing area of the Pripolyarnii Ural in the rocks of the Proterosoic and Lower Ordovician age. The rock crystal was of Late Permian age. The distributions of the planes with gliding trails depend on the primary anisotropy of the rocks and on the type of stress condition. The specific type of stress condition named variation was marked out. The variation of the type of the stress condition (VSCT) is strictly confined to rock crystal pockets. The already existing planes of nonuniformity in the rocks, which often do not coincide with shear planes, are used in case of a deformation in the last tectonic stress fields. The criteria for distinguishing tectonic stress classes, based on the models of the distribution of tectonic stresses in the surroundings of faults, are suggested.     

Toxicity of sediments from Bahía de Chetumal, México, as assessed by hepatic EROD induction and histology in nile tilapia Oreochromis niloticus.

The effect of environmental pollutants present in sediments obtained from Bahía de Chetumal, a bay on the border between Mexico and Belize, was studied in nile tilapia (Oreochromis niloticus) intraperitoneally injected with sediment extracts from six different sites of the Bay. Sediment samples used for the study contained a variety of organic chemicals such as organochlorine pesticides, polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs). Total cytochrome P-450 and EROD activity were measured in fish liver. Haematological and histological analyses were also carried out. Hepatic P-450 content in treated fish increased from 43 to 240%, and EROD activity from 85 to 160% compared to controls. Extracts from two sampling sites inhibited EROD activity. There were positive significant correlations between P-450 content and the levels of PCBs 44 and 128. EROD activity correlated to HCB, op'-DDE, pp'-DDE, pp'-DDD, mirex and PCB 18 concentrations. Blood examination showed cell degeneration and binucleated leukocytes with abnormal chromatin. Extract treatment also resulted in foci of hyperplasia on the basement of gill lamellae, hypertrophy and oedema in gills and liver necrosis. Control fish showed no abnormalities. The results demonstrate that sediments from Bahía of Chetumal have the potential to cause histopathological, haematological and biochemical alterations in fish. The administration of sediment extracts to fish may serve as a useful test to screen the toxicity of sediments from different areas.     

The duration of acute health problems in people involved with the cleanup operation of the Hebei Spirit oil spill

The authors investigated the duration of health problems of people involved with cleanup efforts for the Hebei Spirit oil spill, which occurred in December 2007 in Taean County, South Korea. The study identified risk factors correlated with the continuation of symptoms. Approximately one year after the accident, 442 people who had participated in the cleanup operation were examined. Data regarding demographic information, risk factors, and the continuation and duration of any symptoms were obtained. Eye symptoms (9.7 months), headaches (8.4 months), skin symptoms (8.3 months), and neurovestibular symptoms (6.9 months) had a relatively longer duration than did back pain (1.8 months) or respiratory symptoms (2.1 months). In particular, the remission of headaches had a negative correlation with female gender (HR 0.57, 0.34-0.95, 95% CI), and remission of eye symptoms had a negative correlation with the total hours of daily participation in the cleanup operation (HR 0.24, 0.06-0.95, 95% CI).