Molards as an indicator of permafrost degradation and landslide processes

Molards have been defined in the past as conical mounds of debris that can form part of a landslide's deposits. We present the first conclusive evidence that molards in permafrost terrains are cones of loose debris that result from thawing of frozen blocks of ice-rich sediments mobilised by a landslide, and hence propose a rigorous definition of this landform in permafrost environments. We show that molards can be used as an indicator of permafrost degradation, and that their morphometry and spatial distribution give valuable insights into landslide dynamics in permafrost environments. We demonstrate that molards are readily recognisable not only in the field, but also in remote sensing data; surveys of historic aerial imagery allow the recognition of relict molards, which can be used as an indicator of current and past permafrost conditions. The triggering of landslides as a result of permafrost degradation will arguably occur more often as global atmospheric temperatures increase, so molards should be added to our armoury for tracking climate change, as well as helping us to understand landslide-related hazards. Finally, we have also identified candidate molards on Mars, so molards can inform about landscape evolution on Earth and other planetary bodies

Unified N=2 Maxwell-Einstein and Yang-Mills-Einstein Supergravity Theories in Four Dimensions

We study unified N=2 Maxwell-Einstein supergravity theories (MESGTs) and unified Yang-Mills Einstein supergravity theories (YMESGTs) in four dimensions. As their defining property, these theories admit the action of a global or local symmetry group that is (i) simple, and (ii) acts irreducibly on all the vector fields of the theory, including the ``graviphoton''. Restricting ourselves to the theories that originate from five dimensions via dimensional reduction, we find that the generic Jordan family of MESGTs with the scalar manifolds [SU(1,1)/U(1)] X [SO(2,n)/SO(2)X SO(n)] are all unified in four dimensions with the unifying global symmetry group SO(2,n). Of these theories only one can be gauged so as to obtain a unified YMESGT with the gauge group SO(2,1). Three of the four magical supergravity theories defined by simple Euclidean Jordan algebras of degree 3 are unified MESGTs in four dimensions. Two of these can furthermore be gauged so as to obtain 4D unified YMESGTs with gauge groups SO(3,2) and SO(6,2), respectively. The generic non-Jordan family and the theories whose scalar manifolds are homogeneous but not symmetric do not lead to unified MESGTs in four dimensions. The three infinite families of unified five-dimensional MESGTs defined by simple Lorentzian Jordan algebras, whose scalar manifolds are non-homogeneous, do not lead directly to unified MESGTs in four dimensions under dimensional reduction. However, since their manifolds are non-homogeneous we are not able to completely rule out the existence of symplectic sections in which these theories become unified in four dimensions.Comment: 47 pages; latex fil

Generalizations of entanglement based on coherent states and convex sets

Unentangled pure states on a bipartite system are exactly the coherent states with respect to the group of local transformations. What aspects of the study of entanglement are applicable to generalized coherent states? Conversely, what can be learned about entanglement from the well-studied theory of coherent states? With these questions in mind, we characterize unentangled pure states as extremal states when considered as linear functionals on the local Lie algebra. As a result, a relativized notion of purity emerges, showing that there is a close relationship between purity, coherence and (non-)entanglement. To a large extent, these concepts can be defined and studied in the even more general setting of convex cones of states. Based on the idea that entanglement is relative, we suggest considering these notions in the context of partially ordered families of Lie algebras or convex cones, such as those that arise naturally for multipartite systems. The study of entanglement includes notions of local operations and, for information-theoretic purposes, entanglement measures and ways of scaling systems to enable asymptotic developments. We propose ways in which these may be generalized to the Lie-algebraic setting, and to a lesser extent to the convex-cones setting. One of our original motivations for this program is to understand the role of entanglement-like concepts in condensed matter. We discuss how our work provides tools for analyzing the correlations involved in quantum phase transitions and other aspects of condensed-matter systems.Comment: 37 page

Unified Maxwell-Einstein and Yang-Mills-Einstein Supergravity Theories in Five Dimensions

Unified N=2 Maxwell-Einstein supergravity theories (MESGTs) are supergravity theories in which all the vector fields, including the graviphoton, transform in an irreducible representation of a simple global symmetry group of the Lagrangian. As was established long time ago, in five dimensions there exist only four unified Maxwell-Einstein supergravity theories whose target manifolds are symmetric spaces. These theories are defined by the four simple Euclidean Jordan algebras of degree three. In this paper, we show that, in addition to these four unified MESGTs with symmetric target spaces, there exist three infinite families of unified MESGTs as well as another exceptional one. These novel unified MESGTs are defined by non-compact (Minkowskian) Jordan algebras, and their target spaces are in general neither symmetric nor homogeneous. The members of one of these three infinite families can be gauged in such a way as to obtain an infinite family of unified N=2 Yang-Mills-Einstein supergravity theories, in which all vector fields transform in the adjoint representation of a simple gauge group of the type SU(N,1). The corresponding gaugings in the other two infinite families lead to Yang-Mills-Einstein supergravity theories coupled to tensor multiplets.Comment: Latex 2e, 28 pages. v2: reference added, footnote 14 enlarge

AORTIC VESSEL WALL PROPERTIES DURING 60 DAYS STRICT HEAD DOWN TILT BEDREST - PRELIMINARY RESULTS OF AGBRESA

Background Changes in large artery properties including increased arterial compliance and increased carotid artery stiffness have been described after space flight. Altered vascular structure, which heralds cardiovascular risk, and reversible changes in vascular function could contribute to the response. Compared with previous studies, which did not reproduce these findings, AGBRESA applied strict -6° head-down bedrest (HDT) mimicking chronic cephalad fluid shifts in space. In this study, we assessed aortic vessel wall properties using state-of-the art imaging methods and pulse wave analysis and tested for possible protective effects of artificial gravity training. Material and Methods We present preliminary data from 12 healthy subjects (8 men, 4 women) obtained during baseline data collection 9-6 days before bedrest (BDC, supine position) and towards the end of two months head down tilt bedrest (MRI on day 56 and echocardiography on day 60 of HDT). Subjects were assigned to 30 minutes per day continuous short arm centrifugation (cAG), 6 times for 5 minutes interval short arm centrifugation, iAG), or a control group (ctr). We assessed aortic pulse wave velocity using oscillometric upper arm and thigh cuffs (PWV-2C, CardioCube, AIT, Vienna, Austria) and 4D-flow cardiac velocity encoded phase contrast magnetic resonance imaging (PWV-4D-MRI). We also measured area, area changes, and distensibility (AoD) of the ascending aorta by 2D-phase contrast cardiac MRI and arterial compliance (Ca) using transthoracic echocardiography. Results Mean aortic area increased in all subjects after 60 days head down tilt bedrest (5.3±0.7 vs. 5.8±0.7 cm², p<0.05). Stroke volume decreased from 94±13 to 84±10 ml (p<0.05) and pulse pressure from 56±11 to 46±9 mmHg (p<0.05) in part through reductions in stroke volume. The figure illustrates individual data on aortic properties (red diamonds = women). In contrast to the more consistent changes in aortic area, stroke volume, and pulse pressure, aortic distensibility, compliance, and pulse wave velocity responses show substantial inter-individual variability. Conclusion The important finding of our study is that 60 days strict head down bedrest elicit consistent changes in ascending aortic area, pulse pressure, and stroke volume. The resulting changes in vascular loading conditions likely confound vascular function measurements, both, in head down bedrest studies and in space

Guidelines for a Space Propulsion Device Based on Heim's Quantum Theory

The text of the calligraphy on the front page means Cosmos, comprising the two chinese symbols for space and time. This calligraphy was done by Hozumi Gensho Roshi, Professor of Applied Sci-ences at Hanazono University, Kyoto, Japan in September 2003. The two red squares depict the sea

Preliminary test results of LGADs from Teledyne e2v for the LHC’s High-Luminosity upgrade

This paper presents initial testing of the first batch of LGAD sensors fabricated by Teledyne e2v in collaboration with the University of Birmingham, University of Oxford, Rutherford Appleton Laboratory and the Open University. Wafers with different energy and dose of the gain layer implant have been characterised with IV, CV and gain measurements. The same set of measurements were made using PiN diodes fabricated on the same wafer as a reference. Results are in-line with expectations and with LGADs produced at more established vendors. Preliminary results suggests Te2v LGADs have a moderate gain in the order of 10 to 50 before irradiation at operational voltages well below breakdown, as required for optimal timing resolution

Decentralization in Africa and the resilience of traditional authorities: Evaluating Zimbabwe’s track record

Zimbabwe has undergone various phases of institutional reform during colonial and post-colonial times either co-opting, distorting or denying the presence of traditional authorities, but somehow none of these institutional engineering episodes managed to uproot them. What in fact happened is successive waves of political institutions designed and put in place during these reforms withered away. Zimbabwe’s traditional authorities are still there and they continue to play a big role in the daily lives of rural populations.This paper looks at one of the most important endogenous factors influencing the workings of decentralization in Zimbabwe. Successive waves of formal institutional change that took place during Zimbabwe’s colonial and post-colonial history have been unable able to uproot the influence of traditional leaders. Due to their home-grown legitimacy, various traditional authorities continue to play an ever-present role in the lives of people in rural areas. But, as it is the case throughout most of Africa, the powers of traditional leaders have mostly been uncodified under modern law and these power relations tend to be rather informal and culturally inaccessible to most outsiders. Consequently, the scholarly literature has not been able to systematically acknowledge their pervasive influence. The article concludes with a reflection on how the influence of traditional authorities can be translated into the democratic and progressive empowerment of rural populations in the developing world