Rockfall characterisation and structural protection: A review

Rockfall is an extremely rapid process involving long travel distances. Due to these features, when an event occurs, the ability to take evasive action is practically zero and, thus, the risk of injury or loss of life is high. Damage to buildings and infrastructure is quite likely. In many cases, therefore, suitable protection measures are necessary. This contribution provides an overview of previous and current research on the main topics related to rockfall. It covers the onset of rockfall and runout modelling approaches, as well as hazard zoning and protection measures. It is the aim of this article to provide an in-depth knowledge base for researchers and practitioners involved in projects dealing with the rockfall protection of infrastructures, who may work in the fields of civil or environmental engineering, risk and safety, the earth and natural sciences.

Structural and electrical properties of Fe-doped TiO2 thin films

The present study discusses the effect of iron doping in TiO2 thin films deposited by rf sputtering. Iron doping induces a structural transformation from anatase to rutile and electrical measurements indicate that iron acts as an acceptor impurity. Thermoelectric power measurement shows a transition between n-type and p-type electrical conduction for an iron concentration around 0.13 at.%. The highest p-type conductivity at room temperature achieved by iron doping was 10(-6) S m(-1).

Sex-chromosome differentiation parallels postglacial range expansion in European tree frogs (Hyla arborea).

Occasional XY recombination is a proposed explanation for the sex-chromosome homomorphy in European tree frogs. Numerous laboratory crosses, however, failed to detect any event of male recombination, and a detailed survey of NW-European Hyla arborea populations identified male-specific alleles at sex-linked loci, pointing to the absence of XY recombination in their recent history. Here, we address this paradox in a phylogeographic framework by genotyping sex-linked microsatellite markers in populations and sibships from the entire species range. Contrasting with postglacial populations of NW Europe, which display complete absence of XY recombination and strong sex-chromosome differentiation, refugial populations of the southern Balkans and Adriatic coast show limited XY recombination and large overlaps in allele frequencies. Geographically and historically intermediate populations of the Pannonian Basin show intermediate patterns of XY differentiation. Even in populations where X and Y occasionally recombine, the genetic diversity of Y haplotypes is reduced below the levels expected from the fourfold drop in copy numbers. This study is the first in which X and Y haplotypes could be phased over the distribution range in a species with homomorphic sex chromosomes; it shows that XY-recombination patterns may differ strikingly between conspecific populations, and that recombination arrest may evolve rapidly (<5000 generations).

Subgroup-specific structural variation across 1,000 medulloblastoma genomes.

Medulloblastoma, the most common malignant paediatric brain tumour, is currently treated with nonspecific cytotoxic therapies including surgery, whole-brain radiation, and aggressive chemotherapy. As medulloblastoma exhibits marked intertumoural heterogeneity, with at least four distinct molecular variants, previous attempts to identify targets for therapy have been underpowered because of small samples sizes. Here we report somatic copy number aberrations (SCNAs) in 1,087 unique medulloblastomas. SCNAs are common in medulloblastoma, and are predominantly subgroup-enriched. The most common region of focal copy number gain is a tandem duplication of SNCAIP, a gene associated with Parkinson's disease, which is exquisitely restricted to Group 4α. Recurrent translocations of PVT1, including PVT1-MYC and PVT1-NDRG1, that arise through chromothripsis are restricted to Group 3. Numerous targetable SCNAs, including recurrent events targeting TGF-β signalling in Group 3, and NF-κB signalling in Group 4, suggest future avenues for rational, targeted therapy.

Structural organization of alpha-subunit from purified and microsomal toad kidney (Na+ + K+)-ATPase as assessed by controlled trypsinolysis

The membrane organization of the alpha-subunit of purified (Na+ + K+)-ATPase ((Na+ + K+)-dependent adenosine triphosphate phosphorylase, EC 3.6.1.3) and of the microsomal enzyme of the kidney of the toad Bufo marinus was compared by using controlled trypsinolysis. With both enzyme preparations, digestions performed in the presence of Na+ yielded a 73 kDa fragment and in the presence of K+ a 56 kDa, a 40 kDa and small amounts of a 83 kDa fragment from the 96 kDa alpha-subunit. In contrast to mammalian preparations (Jørgensen, P.L. (1975) Biochim. Biophys. Acta 401, 399-415), trypsinolysis of the purified amphibian enzyme led to a biphasic loss of (Na+ + K+)-ATPase activity in the presence of both Na+ and K+. These data could be correlated with an early rapid cleavage of 3 kDa from the alpha-subunit in both ionic conditions and a slower degradation of the remaining 93 kDa polypeptide. On the other hand, in the microsomal enzyme, a 3 kDa shift of the alpha-subunit could only be produced in the presence of Na+. Our data indicate that (1) purification of the amphibian enzyme with detergent does not influence the overall topology of the alpha-subunit but produces a distinct structural alteration of its N-terminus and (2) the amphibian kidney enzyme responds to cations with similar conformational transitions as the mammalian kidney enzyme. In addition, anti alpha-serum used on digested enzyme samples revealed on immunoblots that the 40 kDa fragment was better recognized than the 56 kDa fragment. It is concluded that the NH2-terminal of the alpha-subunit contains more antigenic sites than the COOH-terminal domain in agreement with the results of Farley et al. (Farley, R.A., Ochoa, G.T. and Kudrow, A. (1986) Am. J. Physiol. 250, C896-C906).

Euphorbia L. subsect. Esula (Boiss. in DC.) Pax in the Iberian Peninsula. Leaf surface, chromosome numbers and taxonomic treatment

Presentem l'estudi taxonòmic dels représentants d'Euphorbia subsect. Esula a la Península Ibèrica. Prèviament, s'inclou un primer capítol dedicai a l'estudi de les epidermis foliars i un segon capítol sobre nombres cromosòmics...

Auto- and allopolyploidy in Centaurea sect. Acrocentron s.l. (Asteraceae, Cardueae): karyotype and chromosome banding pattern analyses

Dysploidy and polyploidy are well documented in the large genus Centaurea, especially in sect. Acrocentron and in a small group of species from the Iberian Peninsula described as sect. Chamaecyanus, closely related to Acrocentron. We have explored two interesting cases of polyploid series in both sections: the polyploid series of Centaurea toletana in sect. Chamaecyanus and the series of C. ornata group in sect. Acrocentron. We have carried out a karyological study using both classic karyotype analyses and chromosome banding with fluorochromes.

Y chromosome microsatellite isolation from BAC clones in the greater white-toothed shrew (Crocidura russula)

We constructed a microsatellite library from four Crocidura russula Y chromosome-specific bacterial artificial chromosome (BAC) clones. Only one of eight microsatellites was male-specific, despite genome walking to obtain more flanking sequence and testing of 93 primer combinations. Potential reasons for this low success are discussed. The male-specific locus, CRY3, was genotyped in 90 males, including C. russula from across the species range and two related species. The large difference in CRY3 allele size between eastern and western lineages supports earlier reports of high divergence between them. Despite polymorphism of CRY3 in Morocco, only one allele was found throughout the whole of Europe, consistent with previous studies that suggest recent colonization of Europe from a small number of Moroccan founders.

Scale-specific sex-biased dispersal in the Valais shrew unveiled by genetic variation on the Y chromosome, autosomes, and mitochondrial DNA.

We investigated sex specificities in the evolutionary processes shaping Y chromosome, autosomes, and mitochondrial DNA patterns of genetic structure in the Valais shrew (Sorex antinorii), a mountain dwelling species with a hierarchical distribution. Both hierarchical analyses of variance and isolation-by-distance analyses revealed patterns of population structure that were not consistent across maternal, paternal, and biparentally inherited markers. Differentiation on a Y microsatellite was lower than expected from the comparison with autosomal microsatellites and mtDNA, and it was mostly due to genetic variance among populations within valleys, whereas the opposite was observed on other markers. In addition, there was no pattern of isolation by distance for the Y, whereas there was strong isolation by distance on mtDNA and autosomes. We use a hierarchical island model of coancestry dynamics to discuss the relative roles of the microevolutionary forces that may induce such patterns. We conclude that sex-biased dispersal is the most important driver of the observed genetic structure, but with an intriguing twist: it seems that dispersal is strongly male biased at large spatial scale, whereas it is mildly biased in favor of females at local scale. These results add to recent reports of scale-specific sex-biased dispersal patterns, and emphasize the usefulness of the Y chromosome in conjunction with mtDNA and autosomes to infer sex specificities.

Effects of Heat Straightening Structural Steel, MLR-91-3, 1992

Heat straightening of steel beams on bridges struck by over height trucks has become common practice in recent years in Iowa. A study of the effects of this heat straightening on the steel beams thus straightened is needed. Appropriate samples for mechanical and metallurgical tests were cut from the same rolled beam from the end which was heated and the end which was not heated and the test results were compared. The test results showed beyond doubt that the steel was being heated beyond the permitted temperature and that the impact properties are being drastically reduced by the current method of heat straightening.

Retinal vessel oxygen saturation and its correlation with structural changes in retinitis pigmentosa.

PURPOSE: To study the influence of retinal structural changes on oxygen saturation in retinitis pigmentosa (RP) patients. METHODS: Oximetry measurements were performed on 21 eyes of 11 RP patients and compared to 24 eyes of 12 controls. Retinal oxygen saturation was measured in all major retinal arterioles (A-SO₂) and venules (V-SO₂) with an oximetry unit of the retinal vessel analyser (IMEDOS Systems UG, Jena, Germany). Oximetry data were compared with morphological changes measured by Cirrus optical coherence tomography (OCT) (Carl Zeiss Meditec, Dublin, CA, USA, macular thickness protocol). RESULTS: In RP patients, the retinal A-SO₂ and V-SO₂ levels were higher at 99.3% (p = 0.001, anova based on mixed-effects model) and 66.8% (p < 0.001), respectively, and the difference between the two (A-V SO₂) was lower at 32.5% (p < 0.001), when compared to the control group (92.4%; 54.0%; 38.4%, respectively). With the RP group, the A-V SO₂ correlated positively, not only with central macular thickness, but also with retinal thickness, in zones 2 and 3 (p = 0.006, p = 0.007, p = 0.014). CONCLUSION: These data indicate that oxygen metabolism was altered in RP patients. Based on our preliminary results, retinal vessel saturation correlated with structural alterations in RP. This method could be valuable in monitoring disease progression and evaluating a potential therapeutic response.