10-GHz Tenerife cosmic microwave background observations at 8° resolution and their analysis using a new maximum entropy method

The complete set of data from the Tenerife 10-GHz (8° FWHM) twin-horn, drift scan experiment is described. These data are affected by both long-term atmospheric baseline drifts and short-term noise. A new maximum entropy procedure, utilizing the time invariance and spatial continuity of the astronomical signal, is used to achieve a clean separation of these effects from the astronomical signal, and to deconvolve the effects of the beam-switching. We use a fully positive/negative algorithm to produce two-dimensional maps of the intrinsic sky fluctuations. Known discrete sources and Galactic features are identified in the deconvolved map. The data from the 10-GHz experiment, after baseline subtraction with MEM, are then analysed using conventional techniques, and new constraints on Galactic emission are made.     

Temporal variability of disturbances: is this important for diversity and structure of marine fouling assemblages?

Natural communities are constantly changing due to a variety of interacting external processes and the temporal occurrence and intensity of these processes can have important implications for the diversity and structure of marine sessile assemblages. In this study, we investigated the effects of temporal variation in a disturbance regime, as well as the specific timing of events within different regimes, on the composition and diversity of marine subtidal fouling assemblages. We did this in a multi‐factorial experiment using artificial settlement tiles deployed at two sites on the North East coast of England. We found that although there were significant effects of disturbances on the composition of assemblages, there were no effects of either the variation in the disturbance regime or the specific timing of events on the diversity or assemblage composition at either site. In contrast to recent implications we conclude that in marine fouling assemblages, the variability in disturbance regimes (as a driving force) is unimportant, while disturbance itself is an important force for structuring robust ecosystems.     

Population genetics and evolutionary demography of Ucides cordatus (Decapoda: Ocypodidae)

Variation in a fragment of the mitochondrial control region was investigated to assess the population history of the mangrove land crab, Ucides cordatus L., based on 100 individuals from five locations throughout the Brazilian coast. There was considerable variability in the studied fragment, with every individual showing a distinct haplotype. When regions of ambiguous alignment were removed, 90 haplotypes were still recognized, of which only 1 was shared among locations. There was no statistically significant evidence for geographical structure in the pattern of genetic variability based on a nested clade analysis, even though the geographical distances among the farthest collection sites exceeded 3000 km. Moreover, the mismatch distribution of pairwise differences showed a smooth unimodal distribution that is consistent with a recent population expansion of U. cordatus, either when each location was analysed in isolation or when all samples were combined. Interestingly, the estimates for the duration of such expansion vary latitudinally, suggesting that the expansion of the population of U. cordatus proceeded in a southward direction. These results indicate a possible relationship between the growth in the population of the mangrove land crab and the dynamics of mangrove ecosystems during the Quaternary.     

Polychaete Communities Related to Plant Covering in the Médiolittoral and Infralittoral Zones of the Balearic Islands (Western Méditerranean)

Abstract. The polychaete fauna of the subtidal in the médiolittoral and the infralittoral hard bottom zones of the Balearic Islands at depths from 0 to 40m contained 220 species. Five different polychaete communities could be identified by changes in abundance, species richness, species composition, diversity, and trophic structure. In the very clear waters of these islands the infralittoral zone extends to a depth of 40 m and allows us to investigate whether former proposed models of polychaete distribution can be extended to this particular situation.     

Soil liquefaction potential induced by the andalusian earthquake of 25 December 1884

On 25 December 1884, an earthquake of epicentral intensityI ₀ = IX in the MSK scale caused great damage in a large area in the provinces of Granada and Málaga, in the south of Spain. The reports of the Spanish, Italian and French Commissions that studied the earthquake described ground phenomena in seven different sites which can be identified as soil liquefaction.By means of dynamic penetration tests carried out in the above sites, the corresponding soil profiles (based on SPT data and water table depth) were established, and the occurrence of liquefaction was proved in five out of seven of these sites. Also, the intensities at such locations and the magnitude of the earthquake were estimated.From the geotechnical data and the cyclic stress ratio induced by the earthquake, liquefaction conditions were confirmed in all the five sites which presumably liquefied. Then, possible values of the minimum ground surface accelerations necessary for the onset of liquefaction at each location were calculated. The results obtained were completed with data reported in six liquefaction case studies from Japan and the United States, from which design charts relating soil acceleration with normalized SPT values for different intensity levels were drawn.Finally, by using standard attenuation curves, the above data were translated into epicentral distances, and good agreement with the known epicentral area was found. As a result, a consistent approach for liquefaction hazard and source location problems has been developed. The proposed method combines in its formulation historical evidence and earthquake engineering techniques.     

An Interdisciplinary Methodology for the Characterization and Visualization of the Heritage of Roadway Corridors

Roads, particularly since the advent of motorized traffic, have hugely impacted contemporary landscapes. Although their significance was noted in the 1980s, specific roadway‐heritage studies are scarce. Research in different disciplines has identified certain features of roads, but an integrated approach to roadway heritage or a consensus on what this constitutes are lacking. This article proposes an interdisciplinary methodology to assess roadway heritage. Roadways are interpreted within the framework of semantic openness that currently characterizes heritage studies, territory being the basic element of interpretation. Rather than a fragmented approach to conservation, the research defines integrated heritage configurations where natural, cultural, and historical features combine to produce a cohesive form of heritage. GIS (Geographical information systems) technology is used with an online database to assess the complexity of roadway heritage. ICT (Information and communications technology) strategies to raise public awareness are outlined. The methodology is applied to assess the historical N‐340 Mediterranean roadway corridor in Spain.     

The galactic evolution of lithium

Measurements of lithium in stars of different galactic populations such as young open clusters ( Per, Pleiades, Praesepe, Coma, Hyades), very young stellar associations (Taurus-Auriga, Chamaeleon, Ophiuchus clouds), intermediate and old open clusters (NGC 752, M 67, NGC 188), old disc stars and halo stars give us the observational framework from which the galactic evolution of lithium has to be inferred. This element is produced mainly via three mechanisms: primordial nucleosynthesis, spallation reactions in the interstellar medium and thermonuclear reactions in some particular stellar evolutionary stages (novae, red giants). The complicated nucleosynthesis and the fact that astration of lithium in stars is not well understood, makes a direct interpretation of the lithium evolutionary abundance curve difficult. The constraints set by recent lithium measurements in very old open clusters and metal-deficient stars on galactic lithium production mechanisms are discussed. Current problems in the determination of the primordial lithium abundance are briefly reviewed.