Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4

We present a study of the model spin-glass LiHo0.5Er0.5F4 using simultaneous ac susceptibility, magnetization, and magnetocaloric effect measurements along with small angle neutron scattering (SANS) at sub-Kelvin temperatures. All measured bulk quantities reveal hysteretic behavior when the field is applied along the crystallographic c axis. Furthermore, avalanchelike relaxation is observed in a static field after ramping from the zero-field-cooled state up to 200–300 Oe. SANS measurements are employed to track the microscopic spin reconfiguration throughout both the hysteresis loop and the related relaxation. Comparing the SANS data to inhomogeneous mean-field calculations performed on a box of one million unit cells provides a real-space picture of the spin configuration. We discover that the avalanche is being driven by released Zeeman energy, which heats the sample and creates positive feedback, continuing the avalanche. The combination of SANS and mean-field simulations reveal that the conventional distribution of cluster sizes is replaced by one with a depletion of intermediate cluster sizes for much of the hysteresis loop.

Modelling the system behaviour of wet snow avalanches using an expert system approach for risk management on high alpine traffic roads

The presented approach describes a model for a rule-based expert system calculating the temporal variability of the release of wet snow avalanches, using the assumption of avalanche triggering without the loading of new snow. The knowledge base of the model is created by using investigations on the system behaviour of wet snow avalanches in the Italian Ortles Alps, and is represented by a fuzzy logic rule-base. Input parameters of the expert system are numerical and linguistic variables, measurable meteorological and topographical factors and observable characteristics of the snow cover. Output of the inference method is the quantified release disposition for wet snow avalanches. Combining topographical parameters and the spatial interpolation of the calculated release disposition a hazard index map is dynamically generated. Furthermore, the spatial and temporal variability of damage potential on roads exposed to wet snow avalanches can be quantified, expressed by the number of persons at risk. The application of the rule base to the available data in the study area generated plausible results. The study demonstrates the potential for the application of expert systems and fuzzy logic in the field of natural hazard monitoring and risk management.

The 1985 catastrophic drainage of a moraine-dammed lake, Khumbu Himal, Nepal: cause and consequences

On 4 August 1985 Dig Tsho, a moraine-dammed glacial lake in the Khumbu area of eastern Nepal, burst above Thame. For the region close to the origin of the outbreak the consequences were catastrophic. The destruction of a newly built hydroelectricp ower plant, 14 bridges, about 30 houses, and many hectares of valuable arable land, as well as a heavily damaged trail network, resulted from 5 million m3 of water plummetting down the Bhote Kosi and Dudh Kosi valleys. The breaching of the moraine was triggered by wave action following an ice avalanche of 150,000 m3 into the lake. The surge had a peak discharge of 1,600 m3/sec; 3 million m3 of debris were moved within a distance of less than 40 km. However, only 10-15 percent of the material left the region as suspended load. The potential hazard of glacial lakes persists and increases. A hazard assessment including an identificationo f source areas and subsequent monitoring of glacial lakes is proposed. It should be incorporated into any development concept for the Himalayan region.

Relaçoes áridas : Ausência de humanidade em O céu que nos protege

O presente artigo surgiu com o intuito de trazer à luz a análise do filme O céu que nos protege, de Bernardo Bertolucci (1990). Baseado no livro homônimo de Paul Bowles - publicado pela primeira vez em Londres (1949), pela John Lehmann Ltda. - o filme O céu que nos protege narra a história de um casal (Kit, Debra Winger, e Port, John Malkovich) que, em meio à deterioraçao que se instalou na Europa após a Segunda Guerra Mundial, decide conhecer o deserto africano, ao lado de um amigo, Tunner (Campbell Scott), que mais tarde tornar-se-ia amante de Kit. Na trajetória pela Africa, o casal e o amigo terao parcialmente a companhia da família Lyle (Jill Bennett, sra. Lyle, e Timothy Spall, Eric Lyle). Ainda que sob o impacto de uma nova geografia, e, portanto, distante do caos que varria a Europa, Port e Kit traziam consigo a aridez afetiva de um casamento que se arrastava há mais de dez anos. O deserto do Saara anunciar-se-ia como o espelho do próprio estado desertificado do casal - a incomunicabilidade. Frente à ausência de um diálogo genuíno, restava-lhes a frivolidade comportamental, fato que os levaria a uma avalanche de acontecimentos. Impossibilitados de dizerem a verdade acerca de seus anseios e aversoes, Port e Kit deixavam sempre em suspenso aquilo que mais lhes incomodava. Diante de um turbilhao de sentimentos, restava-lhes o medo do ridículo, da impotência, já que é comum tornarmo-nos vulneráveis diante do "outro" para o qual confessamos o nosso sentimento: dá lhe força e insubmissao; e a nós, que despimos nossa alma, dao-nos suscetibilidade e fraqueza, como se estivéssemos à beira de uma mendicância de afeto - seria humilhante. Portanto, Port e Kit caminhavam para o oposto do que pulsava internamente - para o silêncio, e, por conseguinte, para a fugacidade da própria verdade submersa de ambos

(Table 1) Results of geothermal measurements in the Black Sea 2000 and 2001 expeditions

According to the World Ocean Program in the northeastern part of the continental slope of the Black Sea geothermal, seismologic and seismic studies were carried out. An analysis of heat flow distribution allowed to distinguish a negative geothermal anomaly near the Dzhubga area, where the Russia-Turkey pipeline was being constructed. During seismological observations (August-September 1999, September 2001) more than 1200 seismic events were recorded. They proved high tectonic activity of the region under study, which stimulates gravitational sediment transport on the continental slope. The seismo-acoustic survey carried out in the area of the geothermal anomaly revealed no reflecting horizons within the sedimentary cover. This may be related to turbidite-landsliding processes. Results of modeling of the heat flow anomaly showed that it had originated approximately 1000 years ago due to a powerful landslide. This also suggests a possibility of an avalanche displacement of sedimentary masses in the area of the pipeline at present.

Relaçoes áridas : Ausência de humanidade em O céu que nos protege

O presente artigo surgiu com o intuito de trazer à luz a análise do filme O céu que nos protege, de Bernardo Bertolucci (1990). Baseado no livro homônimo de Paul Bowles - publicado pela primeira vez em Londres (1949), pela John Lehmann Ltda. - o filme O céu que nos protege narra a história de um casal (Kit, Debra Winger, e Port, John Malkovich) que, em meio à deterioraçao que se instalou na Europa após a Segunda Guerra Mundial, decide conhecer o deserto africano, ao lado de um amigo, Tunner (Campbell Scott), que mais tarde tornar-se-ia amante de Kit. Na trajetória pela Africa, o casal e o amigo terao parcialmente a companhia da família Lyle (Jill Bennett, sra. Lyle, e Timothy Spall, Eric Lyle). Ainda que sob o impacto de uma nova geografia, e, portanto, distante do caos que varria a Europa, Port e Kit traziam consigo a aridez afetiva de um casamento que se arrastava há mais de dez anos. O deserto do Saara anunciar-se-ia como o espelho do próprio estado desertificado do casal - a incomunicabilidade. Frente à ausência de um diálogo genuíno, restava-lhes a frivolidade comportamental, fato que os levaria a uma avalanche de acontecimentos. Impossibilitados de dizerem a verdade acerca de seus anseios e aversoes, Port e Kit deixavam sempre em suspenso aquilo que mais lhes incomodava. Diante de um turbilhao de sentimentos, restava-lhes o medo do ridículo, da impotência, já que é comum tornarmo-nos vulneráveis diante do "outro" para o qual confessamos o nosso sentimento: dá lhe força e insubmissao; e a nós, que despimos nossa alma, dao-nos suscetibilidade e fraqueza, como se estivéssemos à beira de uma mendicância de afeto - seria humilhante. Portanto, Port e Kit caminhavam para o oposto do que pulsava internamente - para o silêncio, e, por conseguinte, para a fugacidade da própria verdade submersa de ambos

Relaçoes áridas : Ausência de humanidade em O céu que nos protege

O presente artigo surgiu com o intuito de trazer à luz a análise do filme O céu que nos protege, de Bernardo Bertolucci (1990). Baseado no livro homônimo de Paul Bowles - publicado pela primeira vez em Londres (1949), pela John Lehmann Ltda. - o filme O céu que nos protege narra a história de um casal (Kit, Debra Winger, e Port, John Malkovich) que, em meio à deterioraçao que se instalou na Europa após a Segunda Guerra Mundial, decide conhecer o deserto africano, ao lado de um amigo, Tunner (Campbell Scott), que mais tarde tornar-se-ia amante de Kit. Na trajetória pela Africa, o casal e o amigo terao parcialmente a companhia da família Lyle (Jill Bennett, sra. Lyle, e Timothy Spall, Eric Lyle). Ainda que sob o impacto de uma nova geografia, e, portanto, distante do caos que varria a Europa, Port e Kit traziam consigo a aridez afetiva de um casamento que se arrastava há mais de dez anos. O deserto do Saara anunciar-se-ia como o espelho do próprio estado desertificado do casal - a incomunicabilidade. Frente à ausência de um diálogo genuíno, restava-lhes a frivolidade comportamental, fato que os levaria a uma avalanche de acontecimentos. Impossibilitados de dizerem a verdade acerca de seus anseios e aversoes, Port e Kit deixavam sempre em suspenso aquilo que mais lhes incomodava. Diante de um turbilhao de sentimentos, restava-lhes o medo do ridículo, da impotência, já que é comum tornarmo-nos vulneráveis diante do "outro" para o qual confessamos o nosso sentimento: dá lhe força e insubmissao; e a nós, que despimos nossa alma, dao-nos suscetibilidade e fraqueza, como se estivéssemos à beira de uma mendicância de afeto - seria humilhante. Portanto, Port e Kit caminhavam para o oposto do que pulsava internamente - para o silêncio, e, por conseguinte, para a fugacidade da própria verdade submersa de ambos

Global glacier changes

Changes in glaciers and ice caps provide some of the clearest evidence of climate change, and as such they constitute key variables for early detection strategies in global climate-related observations. These changes have impacts on global sea level fluctuations, the regional to local natural hazard situation, as well as on societies dependent on glacier meltwater. Internationally coordinated collection and publication of standardised information about ongoing glacier changes was initiated back in 1894. The compiled data sets on the global distribution and changes in glaciers and ice caps provide the backbone of the numerous scientific publications on the latest findings about surface ice on land. Since the very beginning, the compiled data has been published by the World Glacier Monitoring Service and its predecessor organisations. However, the corresponding data tables, formats and meta-data are mainly of use to specialists.

Hydrocarbons in particulate matter and bottom sediments from the north Caspian Sea shelf

Data are presented on content and composition of hydrocarbons (HC) (aliphatic AHC and polyaromatic PAH) in filtered particulate matter and in the surface layer of bottom sediments from the northern shelf of the Caspian Sea and related to data on their contents in the Volga River estuary. Because of transformation and precipitation of anthropogenic and natural compounds, HC composition in particulate matter and bottom sediments undergoes transformations caused by mixing of fresh and saline waters (in bottom sediments, within concentration ranges 70.4-4557.9 µg/g for AHC and 3.8-4800 ng/g for PAH). It was found that the greatest concentrating of HC proceeds in the region of the avalanche sedimentation, and their contents are independent of grain-size types of bottom sediments. Anthropogenic HC (oil and pyrogenous) do not get over the marginal filter of the Volga River and do not pass to the open part of the sea.

Map of Nördliches Bockkar Kees 1979

A new map of Nördliche Bockkarkees (Glocknergroup, Hohe Tauern, Eastern Alps) has been produced in a scale of I : 10000. As a basis an aerophotogrammetric survey on September 18, 1979 was used. The original photogrammetric stereoplotting was in ascale of I : 5000. The map is printed in four coloures with 10m contourlines. Rapid motion of the glacier tongue and ice avalanches up to several million cubic meters occure on Nördliches Bockkarkees frequently. The position of the glacier is shown three weeks before a glacier avalanche broke off the tongue on October 5./6., 1979. The large-scale map represents a contribution to the investigation of the recurrent ice avalanches at this glacier and is one of the necessary preconditions for further research.

Physical/chemical properties and stable oxygen and carbon isotope records of Holocene to late Pleistocene sediments in the Gela Basin, central Mediterranean Sea

The Holocene Twin Slides form the most recent of recurrent mass wasting events along the NE portion of Gela Basin within the Sicily Channel, central Mediterranean Sea. Here, we present new evidence on the morphological evolution and stratigraphic context of this coeval slide complex based on deepdrilled sediment sequences providing a >100 ka paleo-oceanographic record. Both Northern (NTS) and Southern Twin Slide (STS) involve two failure stages, a debris avalanche and a translational slide, but are strongly affected by distinct preconditioning factors linked to the older and buried Father Slide. Core-acoustic correlations suggest that sliding occurred along sub-horizontal weak layers reflecting abrupt physical changes in lithology or mechanical properties. Our results show further that headwall failure predominantly took place along sub-vertical normal faults, partly through reactivation of buried Father Slide headscarps.

Promising Prospects in Mobile Search: Business As Usual or Techno-Economic Disruptions?

It has taken more than a decade of intense technical and market developments for mobile Internet to take off as a mass phenomenon. And it has arrived with great intensity: an avalanche of mobile content and applications is now overrunning us. Similar to its wired counterpart, wireless Web users will continuously demand access to data and content in an efficient and user-friendly manner.

Single phase a-plane MgZnO epilayers for UV optoelectronics: substitutional behaviour of Mg at large contents

High quality 1 μm thick a-plane MgxZn1−xO layers were produced by molecular beam epitaxy with Mg contents higher than 50%. Resonant Rutherford backscattering spectrometry combined with ion channeling revealed a uniform growth in both composition and atomic order. The lattice-site location of Mg, Zn and O elements was determined independently, proving the substitutional behaviour of Mg in Zn-sites of the wurtzite lattice. X-Ray diffraction pole figure analysis also confirms the absence of phase separation. Optical properties at such high Mg contents were studied in Schottky photodiodes.

Topological invariance and spatial scaling of surface roughness in two highly eroded zones of Mexico: a comparative study

The Fractal Image Informatics toolbox (Oleschko et al., 2008 a; Torres-Argüelles et al., 2010) was applied to extract, classify and model the topological structure and dynamics of surface roughness in two highly eroded catchments of Mexico. Both areas are affected by gully erosion (Sidorchuk, 2005) and characterized by avalanche-like matter transport. Five contrasting morphological patterns were distinguished across the slope of the bare eroded surface of Faeozem (Queretaro State) while only one (apparently independent on the slope) roughness pattern was documented for Andosol (Michoacan State). We called these patterns ?the roughness clusters? and compared them in terms of metrizability, continuity, compactness, topological connectedness (global and local) and invariance, separability, and degree of ramification (Weyl, 1937). All mentioned topological measurands were correlated with the variance, skewness and kurtosis of the gray-level distribution of digital images. The morphology0 spatial dynamics of roughness clusters was measured and mapped with high precision in terms of fractal descriptors. The Hurst exponent was especially suitable to distinguish between the structure of ?turtle shell? and ?ramification? patterns (sediment producing zone A of the slope); as well as ?honeycomb? (sediment transport zone B) and ?dinosaur steps? and ?corals? (sediment deposition zone C) roughness clusters. Some other structural attributes of studied patterns were also statistically different and correlated with the variance, skewness and kurtosis of gray distribution of multiscale digital images. The scale invariance of classified roughness patterns was documented inside the range of five image resolutions. We conjectured that the geometrization of erosion patterns in terms of roughness clustering might benefit the most semi-quantitative models developed for erosion and sediment yield assessments (de Vente and Poesen, 2005).