Core-mantle boundary deformations and J2 variations resulting from the 2004 Sumatra earthquake

The deformation at the core-mantle boundary produced by the 2004 Sumatra earthquake is investigated by means of a semi-analytic theoretical model of global coseismic and postseismic deformation, predicting a millimetric coseismic perturbation over a large portion of the core-mantle boundary. Spectral features of such deformations are analysed and discussed. The time-dependent postseismic evolution of the elliptical part of the gravity field (J2) is also computed for different asthenosphere viscosity models. Our results show that, for asthenospheric viscosities smaller than 10^18 Pa s, the postseismic J2 variation in the next years is expected to leave a detectable signal in geodetic observations.Comment: 14 pages, 8 figures, 1 table. It will appear in Geophysical Journal Internationa

Environmental magnetic records of mid-late Pleistocene drift sedimentary sequences from the Antarctic Peninsula, Pacific margin

The Pacific Continental Margin of the Antarctic Peninsula was the area of interest of the Sediment Drift of The Antarctic Offshore Project (SEDANO Project). A paleomagnetic and environmental study was carried out on four Pleistocene sequences from Drift 7. High resolution measurements were performed on u-channels and about forty-three discrete samples. This work focus on the definition of the mineralogy of the main magnetic carriers which is still matter of debate and on the study of the short time variability of magnetite grain-size which results particularly evident during the last glaciation. ARM/κ magnetic parameter resulted to be a good record of such variability and reflects changes in the sedimentation on the rise when the ice sheet was probably closer to the continental shelf edge. An integrated age model has been provided for cores SED-12 and -13, which have the higher sedimentation rates

Environmental magnetic records of Mid-Late Pleistocene drift sedimentary sequences from the Antarctic Peninsula, Pacific Margin

The Pacific Continental Margin of the Antarctic Peninsula was the area of interest of the Sediment Drift of The Antarctic Offshore Project (SEDANO Project). A paleomagnetic and environmental study was carried out on four Pleistocene sequences from Drift 7. High resolution measurements were performed on u-channels and about forty-three discrete samples. This work focus on the definition of the mineralogy of the main magnetic carriers which is still matter of debate and on the study of the short time variability of magnetite grain-size which results particularly evident during the last glaciation. ARM/k magnetic parameter resulted to be a good record of such variability and reflects changes in the sedimentation on the rise when the ice sheet was probably closer to the continental shelf edge. An integrated age model has been provided for cores SED-12 and -13, which have the higher sedimentation rates

Selenium Nanoparticles for Biomedical Applications: From Development and Characterization to Therapeutics

Selenium (Se) is an essential element to human health that can be obtained in nature through several sources. In the human body, it is incorporated into selenocysteine, an amino acid used to synthesize several selenoproteins, which have an active center usually dependent on the presence of Se. Although Se shows several beneficial properties in human health, it has also a narrow therapeutic window, and therefore the excessive intake of inorganic and organic Se-based compounds often leads to toxicity. Nanoparticles based on Se (SeNPs) are less toxic than inorganic and organic Se. They are both biocompatible and capable of effectively delivering combinations of payloads to specific cells following their functionalization with active targeting ligands. Herein, the main origin of Se intake, its role on the human body, and its primary biomedical applications are revised. Particular focus will be given to the main therapeutic targets that are explored for SeNPs in cancer therapies, discussing the different functionalization methodologies used to improve SeNPs stability, while enabling the extensive delivery of drug-loaded SeNP to tumor sites, thus avoiding off-target effects.Peer reviewe

Practice of walking and its association with perceived environment among elderly Brazilians living in a region of low socioeconomic level

<p>Abstract</p> <p>Background</p> <p>The aim of this study was analyze associations between the practice of walking and environmental perception among elderly Brazilians in a region of low socioeconomic level.</p> <p>Methods</p> <p>A cross-sectional study was conducted among 385 elderly people aged 60 years and over. To evaluate walking, the International Physical Activity Questionnaire (IPAQ), long version (leisure and transport modules) was used. The environment was evaluated by means of the Neighborhood Environmental Walkability Scale (NEWS) (adapted Brazilian version). For the statistical analysis, multiple logistic regression models were created separately for men and women. The practice of at least 150 minutes a week of walking was the dependent variable, and the variables of environmental perception were the independent variables. All the models were controlled for schooling level and age.</p> <p>Results</p> <p>The proportion of elderly people active in walking was 56.9% for the men and 26.4% for the women. The perception of the presence of soccer fields (OR = 4.12) and their proximity, within ten minutes' walk from home (OR = 3.43), were associated with the practice of walking among the men. The perception of the presence of public squares (OR = 4.70) and the proximity of primary healthcare units, within ten minutes' walk from home (OR = 3.71), were associated with the practice of walking among the women. An association with adequate perception of vehicle traffic remained at the threshold of significance for the women.</p> <p>Conclusion</p> <p>Accessibility of leisure structures such as football fields and public squares and of health services such as primary healthcare units were important environmental variables associated with the practice of walking among elderly people living in a region of low socioeconomic level in Brazil. These variables need to be taken into consideration when aiming to promote the practice of walking among elderly people living in similar regions.</p

Fractal Descriptors in the Fourier Domain Applied to Color Texture Analysis

The present work proposes the development of a novel method to provide descriptors for colored texture images. The method consists in two steps. In the first, we apply a linear transform in the color space of the image aiming at highlighting spatial structuring relations among the color of pixels. In a second moment, we apply a multiscale approach to the calculus of fractal dimension based on Fourier transform. From this multiscale operation, we extract the descriptors used to discriminate the texture represented in digital images. The accuracy of the method is verified in the classification of two color texture datasets, by comparing the performance of the proposed technique to other classical and state-of-the-art methods for color texture analysis. The results showed an advantage of almost 3% of the proposed technique over the second best approach.Comment: Chaos, Volume 21, Issue 4, 201

Paleomagnetic constraints on the Plio-Pleistocene geodynamic evolution of the external central-northern Apennines (Italy)

We report on new paleomagnetic results obtained from 27 sites sampled in the Plio-Pleistocene sequences at the external front of the central-northern Apennines. Previous analyses of Miocene (Messinian) sediments indicated that the present shape of the northern Apenninic arc is due to the oroclinal bending of an originally straight belt oriented around N320° and that vertical axis rotations accompanied the migration of the thrust fronts toward the Adriatic foreland [F. Speranza et al., J. Geophys. Res. 102 (1997) 3153-3166]. We tried to provide new paleomagnetic constraints for the timing and rates of the oroclinal bending process during the Pliocene and the Pleistocene. The results suggest that CCW rotations observed in the northern part of the studied area are possibly younger than 3 Ma. No regional rotation is recorded in the Pliocene and Pleistocene sediments from the southern part of the study area, analogously to the Messinian sediments of the 'Acquasanta' domain of Speranza et al. [F. Speranza et al., J. Geophys. Res. 102 (1997) 3153-3166]. A local significant CCW rotation (23° ± 10°) is identified in the Early Pleistocene sediments that crop out along the Adriatic coast between Ascoli and Pescara, indicating differential motion of the thrust sheets. This rotation must be younger than 1.43 Ma

Andic soils and catastrophic mudflows in Italy: morphological and hydropedological evidences

In Italy rapid landslides are the most frequently occurring natural disasters and, after earthquakes, cause the highest number of victims. In this contribution we attempt to prove that there exist a tight connection between the presence of a specific soil type, namely andic soils, and the occurrence of the main catastrophic mudflows and debris flows occurred in Italy in the last decades. The study was performed by means of an integrated pedological and hydrological analysis on the detachment crowns of some of the most important catastrophic mudflows and debris flows occurred in Italy in the last decades and involving/evolving surface soils. The results at both regional (Campania) and National (Italy) scale clearly show that despite the large variability of the environmental settings of the studied sites there are indeed some striking homogeneous soil features in the detachment crowns including (i) soil morphology, (ii) andic features ranging from high to moderate, (iii) high water retention throughout a large range of pressure heads. Results seem to reveal clear cause-effect evidences between andic soils and the investigated catastrophic mudflows/debrisflows; this must be related to the unique physical properties of these soils inducing high landslide vulnerability

IDIOPATHIC PARTIAL EPILEPSY WITH AUDITORY FEATURES (IPEAF): A CLINICAL AND GENETIC STUDY OF 53 SPORADIC CASES

The purpose of our study was to describe the clinical characteristics of sporadic (S) cases of partial epilepsy with auditory features (PEAF) and pinpoint clinical, prognostic and genetic differences with respect to previously reported familial (F) cases of autosomal dominant partial epilepsy with auditory features (ADPEAF). We analysed 53 patients (24 females and 29 males) with PEAF diagnosed according to the following criteria: partial epilepsy with auditory symptoms, negative family history for epilepsy and absence of cerebral lesions on NMR study. All patients underwent a full clinical, neuroradiological and neurophysiological examination. Forty patients were screened for mutations in LGI1/epitempin, which is involved in ADPEAF. Age at onset ranged from 6 to 39 years (average 19 years). Secondarily generalized seizures were the most common type of seizures at onset (79%). Auditory auras occurred either in isolation (53%) or associated with visual, psychic or aphasic symptoms. Low seizure frequency at onset and good drug responsiveness were common, with 51% of patients seizure-free. Seizures tended to recur after drug withdrawal. Clinically, no major differences were found between S and F patients with respect to age at onset, seizure frequency and response to therapy. Analysis of LGI1/epitempin exons failed to disclose mutations. Our data support the existence of a peculiar form of non-lesional temporal lobe epilepsy closely related to ADPEAF but without a positive family history. This syndrome, here named IPEAF, has a benign course in the majority of patients and could be diagnosed by the presence of auditory aura. Although LGI1 mutations have been excluded, genetic factors may play an aetiopathogenetic role in at least some of these S cases

Core-mantle boundary deformations triggered by the Sumatra earthquake

The devastating megathrust earthquake of December 26 2004 off the west coast of northern Sumatra has been probably the largest since the 1960 Chile event. The occurrence of this event revived the debate, among the scientific community, upon several open geophysical problems possibly connected with the energy release of giant earthquakes. One of these problems concerns the origin of geomagnetic jerks and its eventual relationship with large seismic activity. Though a final answer to this question seems not to be at hand presently, this answer (whatever positive or negative) appears to be connected with the possibility that giant seismic events could cause significant changes in the CMB topography. Until now, no attempts have been made to compute the impact of a seismic event on the CMB: the great Sumatra earthquake, for the first time, gave unambiguous instrumental evidence that the deformation field associated with a giant event is detectable at distances up to several thousands of km with a magnitude of the displacements of the order of 1 mm. Since perturbations to the CMB even smaller than this value are likely to be able to produce a geomagnetic jerk, a precise evaluation of the CMB topography perturbation associated with a giant earthquake like Sumatra has become an important scientific question