Evaluating tephrochronology in the permafrost peatlands of Northern Sweden

Tephrochronology is an increasingly important tool for the dating of sediment and peat profiles for palaeoecological, palaeoclimatic and archaeological research. However, although much work has been done on tephra in temperate peatlands, there have been very few in-depth investigations of permafrost peatlands. Here we present the analysis of nine peatland cores from Abisko, northern Sweden, and show that the presence of tephra layers may be highly variable even over a scale of <10 km. Using electron probe microanalysis (EPMA) combined with age-depth profiles compiled from radiocarbon (14C) and 210Pb dating of peat records, we identify the Hekla 1104, Hekla 1158, Hekla-Selsund and the Hekla 4 tephra layers. We also infer the presence of the Askja 1875 tephra, in addition to an unassigned tephra dating from between 1971–1987 AD in two separate cores. Five of the nine analysed cores do not contain distinct tephra layers. Volcanic ash deposits in northern Scandinavia are subject to both regional-scale variations in climate and atmospheric circulation, and local-scale variations on the order of tens of kilometres in topography, vegetation, snow cover, and ground permeability. The extreme inconsistency of tephra preservation within a small study area (∼3000 km2) brings into question the reliability of tephrochronology within permafrost peatlands, and highlights the necessity of alternative methods for dating peat profiles in this region

Chaste: an open source C++ library for computational physiology and biology

Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to "re-invent the wheel" with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials

Children with autism deserve evidence-based intervention

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Jennifer J Couper and Amanda J Sampso

An assessment of the integration between corporate social responsibility practices and management systems in Brazil aiming at sustainability in enterprises

The concept of corporate social responsibility (CSR) is associated with the idea that every organization should integrate environmental, economic and social issues as part of their organizational philosophy. In companies with a higher degree of development in terms of CSR, sustainable practices are integrated into management systems. When focusing on Latin America, this integration may be at its first steps, but there is a vacuum in the literature in this field. Based on this reality, this paper aims to evaluate the integration between CSR practices and management systems in companies in Brazil based on experts’ perceptions. Employing a conceptual model covering how stakeholder demands are incorporated in organizational practices using a continuous improvement approach, we performed a survey with experts in the area. Results revealed opportunities for improvements in all CSR practices evaluated, most of which were considered by the experts to have been implemented only superficially. In a comparative analysis, two practices stood out in relation to the others: reporting of CSR results to stakeholders and evaluation of the performance of CSR activities using pre-established indicators. Practices associated with planning of CSR activities are the most superficially implemented, adversely affecting CSR performance. The authors believe that the findings of this study could be useful for business managers and academics as guidance towards improved CSR efforts

Identifying a High Fraction of the Human Genome to be under Selective Constraint Using GERP++

Computational efforts to identify functional elements within genomes leverage comparative sequence information by looking for regions that exhibit evidence of selective constraint. One way of detecting constrained elements is to follow a bottom-up approach by computing constraint scores for individual positions of a multiple alignment and then defining constrained elements as segments of contiguous, highly scoring nucleotide positions. Here we present GERP++, a new tool that uses maximum likelihood evolutionary rate estimation for position-specific scoring and, in contrast to previous bottom-up methods, a novel dynamic programming approach to subsequently define constrained elements. GERP++ evaluates a richer set of candidate element breakpoints and ranks them based on statistical significance, eliminating the need for biased heuristic extension techniques. Using GERP++ we identify over 1.3 million constrained elements spanning over 7% of the human genome. We predict a higher fraction than earlier estimates largely due to the annotation of longer constrained elements, which improves one to one correspondence between predicted elements with known functional sequences. GERP++ is an efficient and effective tool to provide both nucleotide- and element-level constraint scores within deep multiple sequence alignments

Stochastic Gravity: Theory and Applications

Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel.In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime: we compute the two-point correlation functions for the linearized Einstein tensor and for the metric perturbations. Second, we discuss structure formation from the stochastic gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit

Amyloid in the islets of Langerhans: Thoughts and some historical aspects

Deposition of amyloid, derived from the polypeptide hormone islet amyloid polypeptide (IAPP; ‘amylin’) is the single most typical islet alteration in type 2 diabetes. Islet amyloid was described as hyalinization already in 1901, but not until 1986 was it understood that it is a polymerization product of a novel β-cell regulatory product. The subject of this focused review deals with the pathogenesis and importance of the islet amyloid itself, not with the biological effect of the polypeptide. Similar to the situation in Alzheimer's disease, it has been argued that the amyloid may not be of importance since there is no strict correlation between the degree of islet amyloid infiltration and the disease. However, it is hardly discussable that the amyloid is important in subjects where islets have been destroyed by pronounced islet amyloid deposits. Even when there is less islet amyloid the deposits are widely spread, and β-cells show ultrastructural signs of cell membrane destruction. It is suggested that type 2 diabetes is heterogeneous and that in one major subtype aggregation of IAPP into amyloid fibrils is determining the progressive loss of β-cells. Interestingly, development of islet amyloid may be an important event in the loss of β-cell function after islet transplantation into type 1 diabetic subjects

Towards strange metallic holography

We initiate a holographic model building approach to `strange metallic' phenomenology. Our model couples a neutral Lifshitz-invariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by D-branes. In the physical regime of temperature much lower than the charge density and gap, we exhibit anomalous scalings of the temperature and frequency dependent conductivity. Choosing the dynamical critical exponent $z$ appropriately we can match the non-Fermi liquid scalings, such as linear resistivity, observed in strange metal regimes. As part of our investigation we outline three distinct string theory realizations of Lifshitz geometries: from F theory, from polarised branes, and from a gravitating charged Fermi gas. We also identify general features of renormalisation group flow in Lifshitz theories, such as the appearance of relevant charge-charge interactions when $z \geq 2$. We outline a program to extend this model building approach to other anomalous observables of interest such as the Hall conductivity.Comment: 71 pages, 8 figure