Numerical test of a newV-profile inversion technique

The diagnostic method proposed by Landi Degl'Innocenti and Landolfi (1982), based on the observation of circular polarization, has been generalized to derive the thermodynamic properties of unresolved magnetic elements in the solar atmosphere. The final aim is to derive the height dependence of several parameters of the flux tube atmosphere (such as temperature, magnetic field and velocity distributions, macroturbulence and filling factor). We have used a perturbation method based on the concept of response functions for the Stokes profiles introduced by Landi Degl'Innocenti and Landi Degl'Innocenti (1977). We present here the preliminary results of invertingV-profiles by an iterative standard least-squares technique, which allows to find the magnetic 1-D atmosphere consistent with simulated data.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

SIR: An Inversion Technique of Spectral Lines

During the last years, inversion techniques have become one of the most powerful tools to obtain, from spectropolarimetric data, the stratification of physical quantities (temperature, pressure, velocity fields, magnetic field, etc.) describing different structures in the solar atmosphere. The SIR code (Stokes Inversion based on Response functions), developed at the Instituto de Astrofísica de Canarias (IAC), is internationally acknowledged nowadays at the most sophisticated and accurate inversion method. The main results derived from its application to the study of the solar photosphere, are presented. Two recent extensions are reported as well: inversion under NLTE conditions, and the MISS code (Multiline Inversion of Stellar Spectra). This revised version was published online in July 2006 with corrections to the Cover Date.     

A review of the tectonic evolution of the Sunsás belt,SW Amazonian Craton

The Sunsás–Aguapeí province (1.20–0.95 Ga), SW Amazonian Craton, is a key area to study the heterogeneous effects of collisional events with Laurentia, which shows evidence of the Grenvillian and Sunsás orogens. The Sunsás orogen, characterized by an allochthonous collisional-type belt (1.11–1.00 Ga), is the youngest and southwesternmost of the events recorded along the cratonic fringe. Its evolution occurred after a period of long quiescence and erosion of the already cratonized provinces (>1.30 Ga), that led to sedimentation of the Sunsás and Vibosi groups in a passive margin setting. The passive margin stage was roughly contemporary with intraplate tectonics that produced the Nova Brasilândia proto-oceanic basin (<1.21 Ga), the reactivation of the Ji-Paraná shear zone network (1.18–1.12 Ga) and a system of aborted rifts that evolved to the Huanchaca–Aguapeí basin (1.17–1.15 Ga). The Sunsás belt is comprised by the metamorphosed Sunsás and Vibosi sequences, the Rincón del Tigre mafic–ultramafic sill and granitic intrusive suites. The latter rocks yield ε_Nd(t) signatures (?0.5 to ?4.5) and geochemistry (S, I, A-types) suggesting their origin associated with a continental arc setting. The Sunsás belt evolution is marked by “tectonic fronts” with sinistral offsets that was active from c. 1.08 to 1.05 Ga, along the southern edge of the Paraguá microcontinent where K/Ar ages (1.27–1.34 Ga) and the Huanchaca–Aguapeí flat-lying cover attest to the earliest tectonic stability at the time of the orogen. The Sunsás dynamics is coeval with inboard crustal shortening, transpression and magmatism in the Nova Brasilândia belt (1.13–1.00 Ga). Conversely, the Aguapeí aulacogen (0.96–0.91 Ga) and nearby shear zones (0.93–0.91 Ga) are the late tectonic offshoots over the cratonic margin. The post-tectonic to anorogenic stages took place after ca. 1.00 Ga, evidenced by the occurrences of intra-plate A-type granites, pegmatites, mafic dikes and sills, as well as of graben basins. Integrated interpretation of the available data related to the Sunsás orogen supports the idea that the main nucleus of Rodinia incorporated the terrains forming the SW corner of Amazonia and most of the Grenvillian margin, as a result of two independent collisional events, as indicated in the Amazon region by the Ji-Paraná shear zone event and the Sunsás belt, respectively.     

New applications of the Poisson distribution in micropalaeontology: relationships between environmental variables and the Ammonia tepida distribution in the south‐western Spanish estuaries

The application of the Poisson regression to the populations of the benthic foraminifer Ammonia tepida collected in three south‐western Spanish estuaries permits to obtain a quantitative approach between some environmental variables and the number of individuals of this species. Although the three general models are unsatisfactory to predict the observed abundance of this micro‐organism, a partial statistical analysis permits to detect quantitatively the impact of each variable. This analysis indicates an increasing abundance from the high‐salt marshes to the subtidal channels and higher densities in those samples subjected to very euryhaline conditions. Increasing sand percentages show negative effects on the A. tepida abundance, whereas the silt contents do not affect significantly to this species and increasing organic carbon percentages have a small positive effect on the A. tepida densities.     

Interaction between sedimentary processes,historical pollution and microfauna in the Tinto Estuary (SW Spain)

The analysis of a short core collected in the Tinto Estuary (SW Spain) permits to delimitate the influence of historical mining activities on sediments and microfauna (Foraminifera and Ostracoda). In very shallow palaeochannels of the middle estuary, a first mining period (~3,600 cal years BP) caused high sediment pollution by Cu, with a significant diminution of the palaeontological record due to continuous acid mining drainage processes. In this core, the polluted levels derived from both Roman extractions (2,000–1,900 years BP) and the extensive mining activities between 1870 and 1935 have been eroded. The 1,800–200 years BP period is characterized by a limited mining activity and an important improvement of this ecosystem. In addition, the effects of recent industrial wastes have been limited in this area.     

Impact of millennial mining activities on sediments and microfauna of the Tinto River estuary (SW Spain)

In this paper, we analyze two short cores collected in the Tinto estuary (SW Spain), and describe the palaeoenvironmental evolution of this area during the last two millennia, along with the influence of historical mining activities and recent industrial pollution on sediments and microfauna (foraminifera and ostracoda). Although there were no significant changes in the distribution of microorganisms, a first pollution period (0-150 AD) was recorded in high sediment pollution by Cu in the shallow palaeochannels of the middle estuary. During this period and the following 1700 years, tolerant pioneer species of both foraminifera and ostracoda were found predominantly in the inner, protected areas of the estuary, while the bottom sediments were subjected to high hydrodynamic gradients, and consequently showed lower density and diversity of organisms. In the last 150 years, acid mine drainage processes, introduction of a new mining period, and the polluted inputs derived from two industrial processes resulted in increased heavy metal contamination of the bottom sediments, and corresponding extirpation of ostracodes and restriction of foraminifers to the inner zones of the estuary.     

Interrupting a multi-species bioinvasion vector: the efficacy of in-water cleaning for removing biofouling on obsolete vessels

Vector management is the primary method for reducing and preventing nonindigenous species (NIS) invasions and their ecological and economic consequences. This study was the first to examine the efficacy of in-water scrubbing using a submersible cleaning and maintenance platform (SCAMP) to prevent invertebrate species transfers from a heavily fouled obsolete vessel. Initially, prior to treatment, 37 species were recorded in a biofouling matrix that reached 30cm depth in some locations. The bryozoan Conopeum chesapeakensis, and bivalves Mytilopsis leucophaeata and Ischadium recurvum, were dominant sessile species that created structure, supporting mobile biota that included crabs and the associated parasitic barnacle Loxothylacus panopae. Scrubbing had the effect of significantly reducing organism extent and the number of species per sample, but a substantial and diverse (30 species) residual fouling community remained across the entire vessel. Further assessments of management options are needed to prevent potentially damaging NIS transfers. Additional measures taken within an integrated vector management (IVM) strategy may further improve invasion prevention measures.     

Ficus benjamina leaves as indicator of atmospheric pollution: a reconaissance study

We present a diagnostic study to evaluate the suitability of Ficus benjamina tree leaves as a captor of heavy metal particles from atmospheric dusts in urban areas. Leaf samples were taken at 16 localities within three areas in Morelia, state of Michoacán (Mexico??s medium size city, 830000 inhabitants). Measurements of magnetic susceptibility were conducted to determine the magnetic enhancement using samples from green, relatively unpolluted area, as a reference. The samples collected at areas with heavy traffic (main avenues) yielded values almost ten times higher than the values obtained for the unpolluted reference. Isothermal Remanent Magnetization curves are proportional to the degree of pollution. Associations of almost pure magnetite with heavy metals were revealed by scanning electron microscope.     

Oxidative stress, genotoxicity and histopathology biomarker responses in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) liver from Bizerte Lagoon (Tunisia)

The aim of the study was to evaluate the impact of environmental contaminants on oxidative stress, genotoxic and histopathologic biomarkers in liver of mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from a polluted coastal lagoon (Bizerte Lagoon) in comparison to a reference site (the Mediterranean Sea). Antioxidant enzyme activities were lower in fish from the polluted site compared with fish from the reference site, suggesting deficiency of the antioxidant system to compensate for oxidative stress. DNA damage was higher in both fish species from the contaminated site indicating genotoxic effects. The liver histopathological analysis revealed alterations in fish from Bizerte Lagoon. Hepatocytes from both fish species featured extensive lipid-type vacuolation and membrane disruption. Results suggest that the selected biomarkers in both fish species are useful for the assessment of pollution impacts in coastal environments influenced by multiple pollution sources.     

Evaluation of approximate methods to estimate residual drift demands in steel framed buildings

This paper presents the evaluation of two approximate methods recently proposed in the literature to estimate residual (permanent) drift demands at the end of earthquake excitation for seismic assessment of buildings. Both methods require an estimate of the peak (maximum) interstory drift demand and the corresponding drift demand at significant yielding of the building. Additionally, an approximate method is proposed as part of this study. The introduced method follows a coefficient‐based approach similar to the Coefficient Method included in several US documents. For evaluating the approximate methods, five moment‐resisting steel framed buildings having different number of stories were analyzed under four sets of earthquake ground motions. Quantification of the accuracy of the approximate methods to estimate residual drift demands with respect to results from nonlinear time‐history analyses was performed through error measures computed for each building and each set of earthquake ground motions. Results show that the mean standard error tends to increase as the seismic hazard level increases. Between the two methods, the method introduced by Erochko et al. seems more effective in predicting residual drift demands than that proposed in the FEMA P‐58 recommendations in the USA. It is demonstrated that including additional sources of stiffness and strength in the modeling approach constrains the amplitude of residual drift demands. As a beneficial consequence, the accuracy of both approximate methods in predicting residual drift demands is significantly improved (i.e., mean standard error decreases). The introduced method also provides similar accuracy than the approximate methods available in the literature. Copyright © 2015 John Wiley & Sons, Ltd.