The mantle transition zone beneath South America from stacking of P-to-S receiver functions

The Mantle Transition Zone (MTZ) beneath South America is investigated with stacking of Receiver Functions (RFs) of converted P-to-S phases from the velocity discontinuities at 410 km (d410) and 660 km (d660). A total of 785 seismic stations provided 22,235 high quality RFs, allowing 1,717 MTZ thickness measurements in circular bins of 2⁰ radius. An apparent MTZ structure is derived using the IASP91 reference model, where the d410 mean depth is 409.1 km and the d660 is 661.5 km, and the mean MTZ thickness is 251.8 km. This model presents coherent depressions and uplifts of the discontinuities matching well known velocity anomalies. After experimenting with eleven tomography models, a velocity correction adopting the SAW642ANb model with a 50 km top layer of the JOINT model was found to be the best approach towards a true depth model. This model wields a mean d410 at 413.2 km and the d660 at 662.8 km, whereas the MTZ thickness is 249.6 km. The correlation of depths and MTZ thickness variations supports previously determined Clapeyron Slopes (γ) of 2 MPa/K for the d410 and -3 MPa/K for the d660, reconciling γ with seismic observations. The results are fateful to the tectonic structure of South America, where colder-than-normal MTZ anomalies are found along the Andes, while hotter-than-normal anomalies are found along the Atlantic coast. The latter observed MTZ characteristics spatially correspond well with rift related structures and the former to locations where subducted slab has been inferred. The main inference from these observations is that tectonic processes play a major role in the control of thermal and chemical proprieties of the MTZ --Abstract, page iii

Smoluchowski dynamics and the ergodic-nonergodic transition

We use the recently introduced theory for the kinetics of systems of classical particles to investigate systems driven by Smoluchowski dynamics. We investigate the existence of ergodic-nonergodic (ENE) transitions near the liquid-glass transition. We develop a self-consistent perturbation theory in terms of an effective two-body potential. We work to second order in this potential. At second order we have an explicit relationship between the static structure factor and the effective potential. We choose the static structure factor in the case of hard spheres to be given by the solution of the Percus-Yevick approximation for hard spheres. Then using the analytically determined ENE equation for the ergodicity function we find an ENE transition for packing fraction, eta, greater than a critical value eta*=0.76 which is physically unaccessible. The existence of a linear fluctuation-dissipation theorem in the problem is shown and used to great advantage.Comment: 51 pages, 6 figure

Are there localized saddles behind the heterogeneous dynamics of supercooled liquids?

We numerically study the interplay between heterogeneous dynamics and properties of negatively curved regions of the potential energy surface in a model glassy system. We find that the unstable modes of saddles and quasi-saddles undergo a localization transition close to the Mode-Coupling critical temperature. We also find evidence of a positive spatial correlation between clusters of particles having large displacements in the unstable modes and dynamical heterogeneities.Comment: 7 pages, 3 figures, submitted to Europhys. Let

Finite Temperature Dynamical Structure Factor of the Heisenberg-Ising Chain

We consider the spin-1/2 Heisenberg XXZ chain in the regime of large Ising-like anisotropy $\Delta$. By a combination of duality and Jordan-Wigner transformations we derive a mapping to weakly interacting spinless fermions, which represent domain walls between the two degenerate ground states. We develop a perturbative expansion in $1\Delta$ for the transverse dynamical spin structure factor at finite temperatures and in an applied transverse magnetic field. We present a unified description for both the low-energy temperature-activated response and the temperature evolution of the T=0 two-spinon continuum. We find that the two-spinon continuum narrows in energy with increasing temperature. At the same time spectral weight is transferred from the two-spinon continuum to the low energy intraband scattering continuum, which is strongly peaked around the position of the (single) spinon dispersion (`Villain mode').Comment: 23 pages, 19 eps figures (now improved), uses feynm

Lattice Boltzmann model with hierarchical interactions

We present a numerical study of the dynamics of a non-ideal fluid subject to a density-dependent pseudo-potential characterized by a hierarchy of nested attractive and repulsive interactions. It is shown that above a critical threshold of the interaction strength, the competition between stable and unstable regions results in a short-ranged disordered fluid pattern with sharp density contrasts. These disordered configurations contrast with phase-separation scenarios typically observed in binary fluids. The present results indicate that frustration can be modelled within the framework of a suitable one-body effective Boltzmann equation. The lattice implementation of such an effective Boltzmann equation may be seen as a preliminary step towards the development of complementary/alternative approaches to truly atomistic methods for the computational study of glassy dynamics.Comment: 14 pages, 5 figure

The non-invasive 13C-methionine breath test detects hepatic mitochondrial dysfunction as a marker of disease activity in non-alcoholic steatohepatitis

<p>Abstract</p> <p>Introduction</p> <p>Mitochondrial dysfunction plays a central role in the general pathogenesis of non-alcoholic fatty liver disease (NAFLD), increasing the risk of developing steatosis and subsequent hepatocellular inflammation. We aimed to assess hepatic mitochondrial function by a non-invasive ¹³C-methionine breath test (MeBT) in patients with histologically proven NAFLD.</p> <p>Methods</p> <p>118 NAFLD-patients and 18 healthy controls were examined by MeBT. Liver biopsy specimens were evaluated according to the NASH scoring system.</p> <p>Results</p> <p>Higher grades of NASH activity and fibrosis were independently associated with a significant decrease in cumulative ¹³C-exhalation (expressed as cPDR(%)). cPDR_1.5hwas markedly declined in patients with NASH and NASH cirrhosis compared to patients with simple steatosis or borderline diagnosis (cPDR1.5h: 3.24 ± 1.12% and 1.32 ± 0.94% vs. 6.36 ± 0.56% and 4.80 ± 0.88% respectively; p < 0.001). ¹³C-exhalation further declined in the presence of advanced fibrosis which was correlated with NASH activity (r = 0.36). The area under the ROC curve (AUROC) for NASH diagnosis was estimated to be 0.87 in the total cohort and 0.83 in patients with no or mild fibrosis (F0-1).</p> <p>Conclusion</p> <p>The ¹³C-methionine breath test indicates mitochondrial dysfunction in non-alcoholic fatty liver disease and predicts higher stages of disease activity. It may, therefore, be a valuable diagnostic addition for longitudinal monitoring of hepatic (mitochondrial) function in non-alcoholic fatty liver disease.</p

(Co)constructing critical pedagogies: Expanding on our department’s approach to language teaching

In this report, we—the members of a curriculum working group (CWG) in Penn State’s German department—describe our efforts to decenter our German language sequence by integrating critical pedagogies into our department’s existing communicative language teaching (CLT) approach. We trace our process towards this goal, beginning with an exploration into and analysis of two critical pedagogies, namely Antiracist Pedagogy (ARP) and Social Justice Pedagogy (SJP). We ultimately adopt SJP because we find it to be a better fit for our purposes in German language instruction. We offer a framework to evaluate and didacticize existing as well as newly created course materials, guided by social justice (SJ) learning objectives. To illustrate our work, we describe the creation and implementation of an instructional unit in an intermediate German language course. Reflections from this course’s instructor and student reactions concerning this unit’s instruction—as well as SJP in the language classroom in general—make evident the importance of critical perspectives regarding curricular development in fostering equitable classrooms

fixation free inguinal hernia repair with the 3d dynamic responsive prosthesis proflor features procedural steps and long term results

Abstract Background Static and fixated meshes to repair mobile structures like the groin may seem a procedural incongruence. Inguinal hernia is described as a degenerative disease. Therefore, the objective of disease treatment should be the regeneration of wasted tissue. The fibrotic scar plate, a typical biologic response of conventional static meshes, does not represent tissue regeneration but rather a foreign body reaction. These contrasting aspects seem to be related to high complication rates of inguinal herniorrhaphy. Recent studies concerning the pathophysiology of the groin have led to the development of new concepts for repairing inguinal protrusions. A proprietary designed 3D dynamic responsive implant showing regenerative biologic response is the result of this studies. Materials and methods A cohort of 389 individuals underwent open inguinal hernia repair with the 3D dynamic responsive implant following a specific surgical technique. Thanks to the inherent dynamic properties, all procedures were performed without need for fixation of the 3D prosthesis. Results The outcomes of the dynamic hernia repair procedure were reduced postoperative pain and minimized overall complication rates, also long term. Moreover, no patient discomfort or chronic pain was reported. Conclusions Inguinal hernia repair with the 3D dynamic responsive implant ProFlor seems to represent an effective concept change for the treatment of this widespread degenerative disease. Moving in synchrony with the groin, implanted without need of fixation and acting as a regenerative scaffold, ProFlor™ appears to possess all that is needed for a physiologic and pathogenetical consequent treatment of inguinal protrusions leading to a dramatic lessening of intra- and postoperative complications

Observing copepods through a genomic lens

Background: Copepods outnumber every other multicellular animal group. They are critical components of the world's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem service providers, parasites and predators of economically important aquatic animals and potential vectors of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although genomic tools have transformed many areas of biological and biomedical research, their power to elucidate aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited. Discussion: The extraordinary biological and ecological diversity of the subclass Copepoda provides both unique advantages for addressing key problems in aquatic systems and formidable challenges for developing a focused genomics strategy. This article provides an overview of genomic studies of copepods and discusses strategies for using genomics tools to address key questions at levels extending from individuals to ecosystems. Genomics can, for instance, help to decipher patterns of genome evolution such as those that occur during transitions from free living to symbiotic and parasitic lifestyles and can assist in the identification of genetic mechanisms and accompanying physiological changes associated with adaptation to new or physiologically challenging environments. The adaptive significance of the diversity in genome size and unique mechanisms of genome reorganization during development could similarly be explored. Genome-wide and EST studies of parasitic copepods of salmon and large EST studies of selected free-living copepods have demonstrated the potential utility of modern genomics approaches for the study of copepods and have generated resources such as EST libraries, shotgun genome sequences, BAC libraries, genome maps and inbred lines that will be invaluable in assisting further efforts to provide genomics tools for copepods. Summary: Genomics research on copepods is needed to extend our exploration and characterization of their fundamental biological traits, so that we can better understand how copepods function and interact in diverse environments. Availability of large scale genomics resources will also open doors to a wide range of systems biology type studies that view the organism as the fundamental system in which to address key questions in ecology and evolution

Evidence for the validity of Protatlanta sculpta (Gastropoda: Pterotracheoidea)

The genus Protatlanta is thought to be monotypic and is part of the Atlantidae, a family of shelled heteropods. These microscopic planktonic gastropods are poorly known, although research on their ecology is now increasing in response to concerns about the effects of ocean acidification on calcareous plankton. A correctly implemented taxonomy of the Atlantidae is fundamental to this progressing field of research and it requires much attention, particularly using integrated molecular and morphological techniques. Here we use DNA barcoding, shell morphology and biogeography to show that the genus Protatlanta includes at least two valid species in the Atlantic Ocean. Protatlanta souleyeti and Protatlanta sculpta were found to be separate species, with different shell morphology and separated by a K2P genetic distance of 19% sequence divergence at the Cytochrome Oxidase 1 gene. This evidence supports the revival of the species name P. sculpta, which was described by Issel in 1911, but has not been recognised as a valid species since 1915