Some exact non-vacuum Bianchi VI0 and VII0 instantons

We report some new exact instantons in general relativity. These solutions are K\"ahler and fall into the symmetry classes of Bianchi types VI0 and VII0, with matter content of a stiff fluid. The qualitative behaviour of the solutions is presented, and we compare it to the known results of the corresponding self-dual Bianchi solutions. We also give axisymmetric Bianchi VII0 solutions with an electromagnetic field.Comment: latex, 15 pages with 3 eps figure

Hyperextended Scalar-Tensor Gravity

We study a general Scalar-Tensor Theory with an arbitrary coupling funtion $\omega (\phi )$ but also an arbitrary dependence of the ``gravitational constant'' $G(\phi )$ in the cases in which either one of them, or both, do not admit an analytical inverse, as in the hyperextended inflationary scenario. We present the full set of field equations and study their cosmological behavior. We show that different scalar-tensor theories can be grouped in classes with the same solution for the scalar field.Comment: latex file, To appear in Physical Review

Multidimensional Cosmology: Spatially Homogeneous models of dimension 4+1

In this paper we classify all 4+1 cosmological models where the spatial hypersurfaces are connected and simply connected homogeneous Riemannian manifolds. These models come in two categories, multiply transitive and simply transitive models. There are in all five different multiply transitive models which cannot be considered as a special case of a simply transitive model. The classification of simply transitive models, relies heavily upon the classification of the four dimensional (real) Lie algebras. For the orthogonal case, we derive all the equations of motion and give some examples of exact solutions. Also the problem of how these models can be compactified in context with the Kaluza-Klein mechanism, is addressed.Comment: 24 pages, no figures; Refs added, typos corrected. To appear in CQ

Isotropization of Bianchi-Type Cosmological Solutions in Brans-Dicke Theory

The cosmic, general analitic solutions of the Brans--Dicke Theory for the flat space of homogeneous and isotropic models containing perfect, barotropic, fluids are seen to belong to a wider class of solutions --which includes cosmological models with the open and the closed spaces of the Friedmann--Robertson--Walker metric, as well as solutions for models with homogeneous but anisotropic spaces corresponding to the Bianchi--Type metric clasification-- when all these solutions are expressed in terms of reduced variables. The existence of such a class lies in the fact that the scalar field, $\phi$, times a function of the mean scale factor or ``volume element'', $a^3 = a_1 a_2 a_3$, which depends on time and on the barotropic index of the equation of state used, can be written as a function of a ``cosmic time'' reduced in terms of another function of the mean scale factor depending itself again on the barotropic index but independent of the metrics here employed. This reduction procedure permites one to analyze if explicitly given anisotropic cosmological solutions ``isotropize'' in the course of their time evolution. For if so can happen, it could be claimed that there exists a subclass of solutions that is stable under anisotropic perturbations.Comment: 15 pages, Late

Protein aggregate formation permits millennium-old brain preservation

Human proteins have not been reported to survive in free nature, at ambient temperature, for long periods. Particularly, the human brain rapidly dissolves after death due to auto-proteolysis and putrefaction. The here presented discovery of 2600-year-old brain proteins from a radiocarbon dated human brain provides new evidence for extraordinary long-term stability of non-amyloid protein aggregates. Immunoelectron microscopy confirmed the preservation of neurocytoarchitecture in the ancient brain, which appeared shrunken and compact compared to a modern brain. Resolution of intermediate filaments (IFs) from protein aggregates took 2–12 months. Immunoassays on micro-dissected brain tissue homogenates revealed the preservation of the known protein topography for grey and white matter for type III (glial fibrillary acidic protein, GFAP) and IV (neurofilaments, Nfs) IFs. Mass spectrometry data could be matched to a number of peptide sequences, notably for GFAP and Nfs. Preserved immunogenicity of the prehistoric human brain proteins was demonstrated by antibody generation (GFAP, Nfs, myelin basic protein). Unlike brain proteins, DNA was of poor quality preventing reliable sequencing. These long-term data from a unique ancient human brain demonstrate that aggregate formation permits for the preservation of brain proteins for millennia

On the Reaction Diffusion Master Equation in the Microscopic Limit

Stochastic modeling of reaction-diffusion kinetics has emerged as a powerful theoretical tool in the study of biochemical reaction networks. Two frequently employed models are the particle-tracking Smoluchowski framework and the on-lattice Reaction-Diffusion Master Equation (RDME) framework. As the mesh size goes from coarse to fine, the RDME initially becomes more accurate. However, recent developments have shown that it will become increasingly inaccurate compared to the Smoluchowski model as the lattice spacing becomes very fine. In this paper we give a new, general and simple argument for why the RDME breaks down. Our analysis reveals a hard limit on the voxel size for which no local RDME can agree with the Smoluchowski model

Mastering Opportunistic Computing Resources for HEP

As results of the excellent LHC performance in 2016, more data than expected has been recorded leading to a higher demand for computing resources. It is already foreseeable that for the current and upcoming run periods a flat computing budget and the expected technology advance will not be sufficient to meet the future requirements. This results in a growing gap between supplied and demanded resources. One option to reduce the emerging lack of computing resources is the utilization of opportunistic resources such as local university clusters, public and commercial cloud providers, HPC centers and volunteer computing. However, to use opportunistic resources additional challenges have to be tackled. At the Karlsruhe Institute of Technology (KIT) an infrastructure to dynamically use opportunistic resources is built up. In this paper tools, experiences, future plans and possible improvements are discussed

Between tinkering and transformation: A contemporary appraisal of climate change adaptation research on the world's islands

Islands are at the center of discourses on climate change. Yet despite extensive work on diverse island systems in a changing climate, we still lack an understanding of climate change-related responses amongst islands and what shifting from what might be called “tinkering” (perhaps heat warnings) to “transformational” adaptation (perhaps relocation) means for these vastly different landmasses which are often grouped together by default. Through a systematic review of the climate change adaptation scientific literature, this paper critically reflects on how considering islands as a homogenous ensemble and the use of buzzwords such as “transformational adaptation” may be problematic for diverse island realities under climate change. Our findings show that the adaptation evidence base actually provides literature on contrasting island types and cultural and political contexts, including Small Island Developing States as well as other island territories. This study finds research gaps with respect to regions (e.g., South America, Africa, and Mediterranean) and that there is overall both little evidence of and a lack of context-specific definitions of transformational adaptation in island contexts. The adaptation literature does not yet fully reflect the experiences or needs of islands regarding transitions and transformations throughout history