Unified model of hyperthermia via hysteresis heating in systems of interacting magnetic nanoparticles

We present a general study of frequency and magnetic field dependence of the specific heat power produced during field-driven hysteresis cycles in magnetic nanoparticles with relevance to hyperthermia applications in biomedicine. Employing a kinetic Monte-Carlo method with natural time scales allows us to go beyond the assumptions of small driving field amplitudes and negligible inter-particle interactions, which are fundamental to applicability of the standard approach based on linear response theory. The method captures the superparamagnetic and fully hysteretic regimes and the transition between them. Our results reveal unexpected dipolar interaction-induced enhancement or suppression of the specific heat power, dependent on the intrinsic statistical properties of particles, which cannot be accounted for by the standard theory. Although the actual heating power is difficult to predict because of the effects of interactions, optimum heating is in the transition region between the superparamagnetic and fully hysteretic regimes

Macroevolutionary Patterns In The Evolutionary Radiation Of Archosaurs (Tetrapoda: Diapsida)

The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archosaurs were rare components of Early–Middle Triassic faunas, but were more abundant in the Late Triassic and pre-eminent globally by the Early Jurassic. The archosaur radiation was a drawn-out event and major components such as diversity and abundance were discordant from each other. Crurotarsans (crocodile-line archosaurs) were more disparate, diverse, and abundant than avemetatarsalians (bird-line archosaurs, including dinosaurs) during the Late Triassic, but these roles were reversed in the Early Jurassic. There is no strong evidence that dinosaurs outcompeted or gradually eclipsed crurotarsans during the Late Triassic. Instead, crurotarsan diversity decreased precipitously by the end-Triassic extinction, which helped usher in the age of dinosaurian dominance

Beamlike models for the analyses of curved, twisted and tapered horizontal-axis wind turbine (HAWT) blades undergoing large displacements

Abstract. Continuous ongoing efforts to better predict the mechanical behaviour of complex beamlike structures, such as wind turbine blades, are motivated by the need to improve their performance and reduce the costs. However, new design approaches and the increasing flexibility of such structures make their aeroelastic modelling ever more challenging. For the structural part of this modelling, the best compromise between computational efficiency and accuracy can be obtained via schematizations based on suitable beamlike elements. This paper addresses the modelling of the mechanical behaviour of beamlike structures which are curved, twisted and tapered in their unstressed state and undergo large displacements, in- and out-of-plane cross-sectional warping, and small strains. A suitable model for the problem at hand is proposed. Analytical and numerical results obtained by its application are presented and compared with results from 3D FEM analyses

A Non-Sequential Representation of Sequential Data for Churn Prediction

We investigate the length of event sequence giving best predictions when using a continuous HMM approach to churn prediction from sequential data. Motivated by observations that predictions based on only the few most recent events seem to be the most accurate, a non-sequential dataset is constructed from customer event histories by averaging features of the last few events. A simple K-nearest neighbor algorithm on this dataset is found to give significantly improved performance. It is quite intuitive to think that most people will react only to events in the fairly recent past. Events related to telecommunications occurring months or years ago are unlikely to have a large impact on a customer’s future behaviour, and these results bear this out. Methods that deal with sequential data also tend to be much more complex than those dealing with simple nontemporal data, giving an added benefit to expressing the recent information in a non-sequential manner

Arsenic precipitation by an anaerobic arsenic-respiring bacterial strain isolated from the polluted sediments of Orbetello Lagoon, Italy

AIMS: To isolate and characterize an anaerobic bacterial strain from the deeper polluted lagoon sediment able to use as electron acceptors [As(V)] and sulfate (SO4(2-)), using lactate as an electron donor. METHODS AND RESULTS: Methods for isolation from polluted lagoon sediments included anaerobic enrichment cultures in the presence of As(V) and SO4(2-). Reduction of As(V) to As(III) was observed during the growth of the bacterial strain, and the final concentration of As(III) was lower than the initial As(V) one, suggesting the immobilization of As(III) in the yellow precipitate. The precipitate was identified by energy dispersive spectroscopy X-ray as arsenic sulfide. Scanning electron microscopy (SEM) revealed rod-shaped bacterial cells embedded in the precipitate, where net-like formations strictly related to the bacterial cells were visible. The surface of the precipitate showed the adhesion of bacterial cells, forming clusters. Transmission electron microscopy (TEM) also highlighted precipitates inside the bacterial cells and on their surface. Following 16S rRNA sequencing, the bacterial strain 063 was assigned to the genus Desulfosporosinus. CONCLUSIONS: This study reports, for the first time, the isolation from the polluted lagoon sediments of a strain capable of respiring and using As(V) and SO4(2-) as electron acceptors with lactate as the sole carbon and energy source with the formation of an arsenic sulfide precipitate. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of these properties provides novel insight into the possible use of the anaerobic strain in bioremediation processes and also adds to the knowledge on the biogeochemical cycling of arsenic

Phylogenetic stability, tree shape, and character compatibility: a case study using early tetrapods

Phylogenetic tree shape varies as the evolutionary processes affecting a clade change over time. In this study, we examined an empirical phylogeny of fossil tetrapods during several time intervals, and studied how temporal constraints manifested in patterns of tree imbalance and character change. The results indicate that the impact of temporal constraints on tree shape is minimal and highlights the stability through time of the reference tetrapod phylogeny. Unexpected values of imbalance for Mississippian and Pennsylvanian time slices strongly support the hypothesis that the Carboniferous was a period of explosive tetrapod radiation. Several significant diversification shifts take place in the Mississippian and underpin increased terrestrialization among the earliest limbed vertebrates. Character incompatibility is relatively high at the beginning of tetrapod history, but quickly decreases to a relatively stable lower level, relative to a null distribution based on constant rates of character change. This implies that basal tetrapods had high, but declining, rates of homoplasy early in their evolutionary history, although the origin of Lissamphibia is an exception to this trend. The time slice approach is a powerful method of phylogenetic analysis and a useful tool for assessing the impact of combining extinct and extant taxa in phylogenetic analyses of large and speciose clades

Elevated fetal steroidogenic activity in autism

Autism affects males more than females, giving rise to the idea that the influence of steroid hormones on early fetal brain development may be one important early biological risk factor. Utilizing the Danish Historic Birth Cohort and Danish Psychiatric Central Register, we identified all amniotic fluid samples of males born between 1993 and 1999 who later received ICD-10 (International Classification of Diseases, 10th Revision) diagnoses of autism, Asperger syndrome or PDD-NOS (pervasive developmental disorder not otherwise specified) (n=128) compared with matched typically developing controls. Concentration levels of Δ4 sex steroids (progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone) and cortisol were measured with liquid chromatography tandem mass spectrometry. All hormones were positively associated with each other and principal component analysis confirmed that one generalized latent steroidogenic factor was driving much of the variation in the data. The autism group showed elevations across all hormones on this latent generalized steroidogenic factor (Cohen's d=0.37, P=0.0009) and this elevation was uniform across ICD-10 diagnostic label. These results provide the first direct evidence of elevated fetal steroidogenic activity in autism. Such elevations may be important as epigenetic fetal programming mechanisms and may interact with other important pathophysiological factors in autism