Influence of threshold stress on the estimation of the Weibull statistics

The influence of threshold stress on the estimation of the Weibull statistics is discussed in terms of the Akaike information criterion. Numerical simulations show that, if sample data are limited in number and threshold stress is not too large, the two-parameter Weibull distribution is still a preferred choice. For example, the fit of strength data of glass and ceramics to the two- and three-parameter Weibull distributions is compared.

Larval Fish Recruitment and Research in the Americas: Proceedings of the Thirteenth Annual Larval Fish Conference Merida, Mexico, 21-26 May 1989

The 13th Annual Larval Fish Conference and Annual Meeting of the American Fisheries Society Early Life History Section cohosted by Mote Marine Laboratory, United States, and the Instituto Nacional de la Pesca, Mexico, were held 21-26 May 1989, in Merida, Yucatan, Mexico. The purpose of holding the meeting in Mexico was to encourage the participation of our Latin American and Caribbean colleagues and to provide a forum for the exchange of ideas and information among researchers working in the Americas. More than 150 participants represented 24 U.S. states, the District of Columbia, and 13 foreign countries including Mexico, Canada, Puerto Rico, Costa Rico, Panama, Cuba, Columbia, Chile, Peru, Brazil, Argentina, South Africa, and West Germany. The Conference began with registration and a social in the courtyard patio of the Merida Holiday Inn. Fresh red grouper, the most important commercial finfish species of the State of Yucatan, was prepared and served by the hotel staff, courtesy of CPI, Itzamex, and the Terramar Trading Company. (PDF file contains 146 pages.)

Dog chromosome-specific paints reveal evolutionary inter- and intrachromosomal rearrangements in the American mink and human

Forty chromosome-specific paint probes of the domestic dog (Canis familiaris, 2n = 78) were used to delineate conserved segments on metaphase chromosomes of the American mink (Mustela vison, 2n = 30) by fluorescence in situ hybridisation. Half of the 38 canine autosomal probes each painted one pair of homologous segments in a diploid mink metaphase, whereas the other 19 dog probes each painted from two to five pairs of discrete segments. In total, 38 canine autosomal paints highlighted 71 pairs of conserved segments in the mink. These painting results allow us to establish a complete comparative chromosome map between the American mink and domestic dog. This map demonstrates that extensive chromosome rearrangements differentiate the karyotypes of the dog and American mink. The 38 dog autosomes could be reconstructed from the 14 autosomes of the American mink through at least 47 fissions, 25 chromosome fusions, and six inversions. Furthermore, comparison of the current dog/mink map with the published human/dog map discloses 23 cryptic intrachromosomal rearrangements in 10 regions of conserved synteny in the human and American mink genomes and thus further refined the human/mink comparative genome map. Copyright (C) 2000 S. Karger AG, Basel.

The breakdown of the viscous regime in riblets

We investigate the mechanisms involved in the breakdown of the viscous regime in riblets, with a view to determining the point of optimum performance, where drag reduction ceases to be proportional to the riblet size. This occurs empirically for a groove cross-section $A_g^+ \approx 120^+$. To study the interaction of the riblets with the overlaying turbulent flow, we systematically conduct DNSes in a ribbed turbulent channel with increasing riblet size. The conditionally averaged crossflow above and within the grooves reveals a mean recirculation bubble that exists up to the point of viscous breakdown, isolating the groove floor from the overlying crossflow, and preventing the high momentum fluid from entering the grooves. We do not find evidence of outside vortices lodging within the grooves until $A_g^+ \approx 400$, which is well past the drag minimum, and already into the drag increasing regime. Interestingly, as the bubble breaks down, we observe that quasi-two-dimensional spanwise structures form just above the riblets, similar to those observed above porous surfaces and plant canopies, which appear to be involved in the performance degradation.

Temperature dependence of the distribution of the first passage time: Results from discontinuous molecular dynamics simulations of an all-atom model of the second beta-hairpin fragment of protein G

More than 22 000 folding kinetic simulations were performed to study the temperature dependence of the distribution of first passage time (FPT) for the folding of an all-atom Go-like model of the second beta-hairpin fragment of protein G. We find that the mean FPT (MFPT) for folding has a U (or V)-shaped dependence on the temperature with a minimum at a characteristic optimal folding temperature T-opt*. The optimal folding temperature T-opt* is located between the thermodynamic folding transition temperature and the solidification temperature based on the Lindemann criterion for the solid. Both the T-opt* and the MFPT decrease when the energy bias gap against nonnative contacts increases. The high-order moments are nearly constant when the temperature is higher than T-opt* and start to diverge when the temperature is lower than T-opt*. The distribution of FPT is close to a log-normal-like distribution at T* greater than or equal to T-opt*. At even lower temperatures, the distribution starts to develop long power-law-like tails, indicating the non-self-averaging intermittent behavior of the folding dynamics. It is demonstrated that the distribution of FPT can also be calculated reliably from the derivative of the fraction not folded (or fraction folded), a measurable quantity by routine ensemble-averaged experimental techniques at dilute protein concentrations.

Control of the orientational order and nonlinear optical response of the "push-pull" chromophore RuPZn via specific incorporation into densely packed monolayer ensembles of an amphiphilic four-helix bundle peptide: characterization of the peptide-chromophore complexes.

"Push-pull" chromophores based on extended pi-electron systems have been designed to exhibit exceptionally large molecular hyperpolarizabilities. We have engineered an amphiphilic four-helix bundle peptide to vectorially incorporate such hyperpolarizable chromophores having a metalloporphyrin moiety, with high specificity into the interior core of the bundle. The amphiphilic exterior of the bundle facilitates the formation of densely packed monolayer ensembles of the vectorially oriented peptide-chromophore complexes at the liquid-gas interface. Chemical specificity designed into the ends of the bundle facilitates the subsequent covalent attachment of these monolayer ensembles onto the surface of an inorganic substrate. In this article, we describe the structural characterization of these monolayer ensembles at each stage of their fabrication for one such peptide-chromophore complex designated as AP0-RuPZn. In the accompanying article, we describe the characterization of their macroscopic nonlinear optical properties.

Predictions of the Pt(8)Ti phase in unexpected systems.

The binary A(8)B phase (prototype Pt(8)Ti) has been experimentally observed in 11 systems. A high-throughput search over all the binary transition intermetallics, however, reveals 59 occurrences of the A(8)B phase: Au(8)Zn(dagger), Cd(8)Sc(dagger), Cu(8)Ni(dagger), Cu(8)Zn(dagger), Hg(8)La, Ir(8)Os(dagger), Ir(8)Re, Ir(8)Ru(dagger), Ir(8)Tc, Ir(8)W(dagger), Nb(8)Os(dagger), Nb(8)Rh(dagger), Nb(8)Ru(dagger), Nb(8)Ta(dagger), Ni(8)Fe, Ni(8)Mo(dagger)*, Ni(8)Nb(dagger)*, Ni(8)Ta*, Ni(8)V*, Ni(8)W, Pd(8)Al(dagger), Pd(8)Fe, Pd(8)Hf, Pd(8)Mn, Pd(8)Mo*, Pd(8)Nb, Pd(8)Sc, Pd(8)Ta, Pd(8)Ti, Pd(8)V*, Pd(8)W*, Pd(8)Zn, Pd(8)Zr, Pt(8)Al(dagger), Pt(8)Cr*, Pt(8)Hf, Pt(8)Mn, Pt(8)Mo, Pt(8)Nb, Pt(8)Rh(dagger), Pt(8)Sc, Pt(8)Ta, Pt(8)Ti*, Pt(8)V*, Pt(8)W, Pt(8)Zr*, Rh(8)Mo, Rh(8)W, Ta(8)Pd, Ta(8)Pt, Ta(8)Rh, V(8)Cr(dagger), V(8)Fe(dagger), V(8)Ir(dagger), V(8)Ni(dagger), V(8)Pd, V(8)Pt, V(8)Rh, and V(8)Ru(dagger) ((dagger) = metastable, * = experimentally observed). This is surprising for the wealth of new occurrences that are predicted, especially in well-characterized systems (e.g., Cu-Zn). By verifying all experimental results while offering additional predictions, our study serves as a striking demonstration of the power of the high-throughput approach. The practicality of the method is demonstrated in the Rh-W system. A cluster-expansion-based Monte Carlo model reveals a relatively high order-disorder transition temperature.

The Evolution of the Russian Romance Through the Nineteenth and Twentieth centuries

This performance dissertation traced the evolution of the Russian romance from 1800 to the present. The Russian romance is a relatively unknown and greatly neglected genre of classical art songs. It is commonly believed that the Russian romance began with Dargomizhsky and Glinka proceeding directly to Tchaikovsky and Rachmaninoff. Forgotten are the composers before Dargornizhsky and Glinka, the bridge composers, and the post-Tchaikovsky and post-Rachmaninoff composers. This may be, in part, because of the difficulties in obtaining Russian vocal scores. While most of the musical world is acquainted with the magnificent Russian instrumental music, the "true soul" of the Russian people lies in its romances. I presented examples of the two different schools of composition, reflecting their philosophical differences in thinking that came about in the 1860s: (1) Russian National school, (2) Western European school. Each school's influence on generations of Russian composers and their pupils have been represented in the recital programs. Also represented was the effect of the October Revolution on music and the voice of the Russian people, Anna Akhmatova. The amount of music that could be included in this dissertation greatly exceeds the amount of available performance time and represents a selected portion of the repertoire. The first recital included repertoire from the beginning of the romance in the early nineteenth century to the beginning of the twentieth century and the second recital focused on the music of the twentieth century, pre and post, the October Revolution. Finally, given the status of Anna Akhmatova and her contributions, the third recital was devoted entirely to her poetry. The "Russian soul" is one of deep, heartfelt emotions and sorrow. Happiness and joy are also present, but always with a touch of melancholy. The audience did not simply go through a musical journey, but took a journey through the "Russian soul". With the strong response of the audience to these recitals, my belief that this repertoire deserves a prominent place in recital programming was confirmed.

Impacts of the Oceans on Climate Change

The oceans play a key role in climate regulation especially in part buffering (neutralising) the effects of increasing levels of greenhouse gases in the atmosphere and rising global temperatures. This chapter examines how the regulatory processes performed by the oceans alter as a response to climate change and assesses the extent to which positive feedbacks from the ocean may exacerbate climate change. There is clear evidence for rapid change in the oceans. As the main heat store for the world there has been an accelerating change in sea temperatures over the last few decades, which has contributed to rising sea‐level. The oceans are also the main store of carbon dioxide (CO2), and are estimated to have taken up ∼40% of anthropogenic-sourced CO2 from the atmosphere since the beginning of the industrial revolution. A proportion of the carbon uptake is exported via the four ocean ‘carbon pumps’ (Solubility, Biological, Continental Shelf and Carbonate Counter) to the deep ocean reservoir. Increases in sea temperature and changing planktonic systems and ocean currents may lead to a reduction in the uptake of CO2 by the ocean; some evidence suggests a suppression of parts of the marine carbon sink is already underway. While the oceans have buffered climate change through the uptake of CO2 produced by fossil fuel burning this has already had an impact on ocean chemistry through ocean acidification and will continue to do so. Feedbacks to climate change from acidification may result from expected impacts on marine organisms (especially corals and calcareous plankton), ecosystems and biogeochemical cycles. The polar regions of the world are showing the most rapid responses to climate change. As a result of a strong ice–ocean influence, small changes in temperature, salinity and ice cover may trigger large and sudden changes in regional climate with potential downstream feedbacks to the climate of the rest of the world. A warming Arctic Ocean may lead to further releases of the potent greenhouse gas methane from hydrates and permafrost. The Southern Ocean plays a critical role in driving, modifying and regulating global climate change via the carbon cycle and through its impact on adjacent Antarctica. The Antarctic Peninsula has shown some of the most rapid rises in atmospheric and oceanic temperature in the world, with an associated retreat of the majority of glaciers. Parts of the West Antarctic ice sheet are deflating rapidly, very likely due to a change in the flux of oceanic heat to the undersides of the floating ice shelves. The final section on modelling feedbacks from the ocean to climate change identifies limitations and priorities for model development and associated observations. Considering the importance of the oceans to climate change and our limited understanding of climate-related ocean processes, our ability to measure the changes that are taking place are conspicuously inadequate. The chapter highlights the need for a comprehensive, adequately funded and globally extensive ocean observing system to be implemented and sustained as a high priority. Unless feedbacks from the oceans to climate change are adequately included in climate change models, it is possible that the mitigation actions needed to stabilise CO2 and limit temperature rise over the next century will be underestimated.

Super-villains of the "real world": the political use of the characterization of villains in Chistopher Nolan's "Dark Knight Trilogy"

It is almost a tradition that celluloid (or digital) villains are represented with some characteristics that remind us the real political enemies of the producer country of the film, or even enemies within the country according to the particular ideology that sustains the film. The case of Christopher Nolan The Dark Knight trilogy, analyzed here, is representative of this trend for two reasons. First, because it gets marked by political radicalization conducted by the US government after the attack of September 11, 2001. Secondly, because it offers a profuse gallery of villains who are outside the circle of friends as the new doctrine “either with us or against us” opened by George Bush for the XXI century. This gallery includes from the very terrorists who justify the War on Terror (Ra's al Ghul, the Joker), to the “radical left” (Bane, Talia al Ghul) including liberal politicians (Harvey Dent), and corrupt that take advantage of the softness of the law to commit crimes with impunity (Dr. Crane, the Scarecrow).