The Messina Straits tsunami of December 28, 1908: a critical review of experimental data and observations

Summary We examine the tsunami which occurred on December 28, 1908, in the Straits of Messina. We collect and review a wide set of data coming from a number of sources in order to get a picture as clear as possible of the generation and evolution of the event. We estimate the tsunami magnitude according to the Murty-Loomis scale, based upon the evaluation of the initial wave disturbance energy.

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Riassunto L'articolo prende in esame il maremoto che colpí lo stretto di Messina la notte del 28 Dicembre 1908. Si passano in rassegna criticamente i dati provenienti da numerose fonti, con l'intento di ottenere un quadro chiaro e non contraddittorio dell'evento. Al termine si propone una stima della magnitudo del maremoto secondo la scala Murty-Loomis, in stretta relazione con l'energia totale posseduta dall'onda al momento della generazione.

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Резюме Мы исследуем дунами, которые имели место 28 декабря 1908 года в Мессинском проливе. Мы собрали и проанализировали данные из ряда источииков, гтобы воссоздать картиину возможного образования и эволюции события. Мы оцениваем магнитуду цунами по шкале Мурти-Лумиса, основываясь на оценке полной энергии, запасенной в волне в момент образования.

     

Use of peptide nucleic acid probes for detecting DNA single-base mutations by capillary electrophoresis

Peptide nucleic acid (PNA) oligomers can be used as probes in pre-gel hybridization experiments, as an alternative to Southern hybridization. In this technique, the PNA probe is hybridized to a cyanine-5 labeled DNA sample denatured at low ionic strength, and the mixture is directly injected for size separation into a capillary electrophoresis (CE) system equipped with laser-induced fluorescence (LIF) detector. The neutral backbone of PNA allows hybridization to occur at low ionic strength and assures an efficient CE separation of the PNA/DNA hybrids from both double-stranded and single-stranded DNA. We have used as a model system the cystic fibrosis R553X and R1162X single-base mutations and we have assessed the influence of various factors, such as temperature and denaturants concentration on DNA/PNA hybrid stability in order to achieve the high specificity required for a single base pair discrimination.     

Evolution of persistent Anthropogenic radioactivity in Antarctic ecosystems

The primary objective of this study was to observe the evolution of anthropogenic radioactivity contamination in the Antarctic continent throughout the period 1997–1999. Moreover, results have been compared with those obtained for previous expeditions, starting from 1987. As far as ¹³⁷Cs is concerned, interesting considerations could be made due to the great amount of available data. On the whole, radioactive contamination seems to be higher in continental than in marine environments. For lake algae, contamination seems to decrease gradually in the order: Tarn Flat, Edmondson Point, Carezza Lake. Focusing on ¹³⁷Cs activity data, a clear temporal decreasing trend was observed in all samples: for sea water, values decreased from mean values of 0.9?Bq/m³ in 1987 to 0.5?Bq/m³ in 1999, a 56% decrease (20% of the total is due to natural decay of ¹³⁷Cs). For lake waters and lake algae, the decreases are higher (80 and 30%, respectively) and the same can be assessed for sediments and soils, even if the resulting distributions are more complicated. The highest values for all radionuclides analysed were detected in terrestrial organisms (mosses, lake algae, and lichens). As a consequence, these matrices appear to be good bioindicators of radioactive contamination. Finally, although the Antarctic continent is affected by some degree by anthropogenic radioactive pollution, our results for ¹³⁷Cs show that we are facing a progressive decrease. Moreover, contamination in other parts of the world is much higher: from 6–10 times in the Mediterranean Sea and 20–50 times in the North Sea and Black Sea.     

Combining Spontaneous Polymerization and Click Reactions for the Synthesis of Polymer Brushes: A “Grafting Onto” Approach

Two novel benzofulvene monomers bearing propargyl or allyl groups have been synthesized by means of readily accessible reactions, and were found to polymerize spontaneously by solvent removal, in the apparent absence of catalysts or initiators, to give the corresponding polybenzofulvene derivatives bearing clickable propargyl or allyl moieties. The clickable propargyl and allyl groups were exploited in appropriate click reactions to develop a powerful and versatile “grafting onto” synthetic methodology for obtaining tailored polymer brushes.     

Impact of electric fields on the speed of contact line in vertical deposition of diluted colloids

We report experimental results on the influence of electric fields on the contact line dynamics of the vertical deposition of water-based diluted colloidal suspensions. We measure the speed of macroscopically receding contact line for different initial concentrations and applied voltages. We explain the observed behavior via the electrophoretic effect in the region near the contact line. The electrophoretic effect induces a concentration gradient along the direction of the applied field which influences the morphology of the dried deposit of colloidal particles. Thus the applied field has an effect on the receding contact line through morphological formation and its transition.     

Terrestrial gamma-ray flashes as powerful particle accelerators

Strong electric discharges associated with thunderstorms can produce terrestrial gamma-ray flashes (TGFs), i.e., intense bursts of x?rays and γ?rays lasting a few milliseconds or less. We present in this Letter new TGF timing and spectral data based on the observations of the Italian Space Agency AGILE satellite. We determine that the TGF emission above 10 MeV has a significant power-law spectral component reaching energies up to 100 MeV. These results challenge TGF theoretical models based on runaway electron acceleration. The TGF discharge electric field accelerates particles over the large distances for which maximal voltages of hundreds of megavolts can be established. The combination of huge potentials and large electric fields in TGFs can efficiently accelerate particles in large numbers, and we reconsider here the photon spectrum and the neutron production by photonuclear reactions in the atmosphere.     

Fermi Liquid Behavior in the 2D Hubbard Model at Low Temperatures

We prove that the weak coupling 2D Hubbard model away from half filling is a Landau Fermi liquid up to exponentially small temperatures. In particular we show that the wave function renormalization is an order 1 constant and essentially temperature independent in the considered range of temperatures and that the interacting Fermi surface is a regular convex curve. This result is obtained by deriving a convergent expansion (which is not a power series) for the two point Schwinger function by Renormalization Group methods and proving at each order suitable power counting improvements due to the convexity of the interacting Fermi surface. Convergence follows from determinant bounds for the fermionic expectations. Communicated by Vincent Rivasseau Submitted: January 4, 2006 Accepted: January 31, 2006