Nonsymmetric transverse vibrations of truncated conical shells technical report no. 3

Resonant frequencies and associated mode shapes of truncated conical shells over wide range of geometrical and modal parameter

Studies of interface damping Summary technical report, 25 Aug. 1967 - 25 Mar. 1968

Air flow and vacuum effects on damping between solid-solid sliding interfaces in aluminum space structures in relation to surface oxide layer

Genes or Culture: Are Mitochondrial Genes Associated with Tool Use in Bottlenose Dolphins ( Tursiops sp.)?

Some bottlenose dolphins use marine sponges as foraging tools (‘sponging'), which appears to be socially transmitted from mothers mainly to their female offspring. Yet, explanations alternative to social transmission have been proposed. Firstly, the propensity to engage in sponging might be due to differences in diving ability caused by variation of mitochondrial genes coding for proteins of the respiratory chain. Secondly, the cultural technique of sponging may have selected for changes in these same genes (or other autosomal ones) among its possessors. We tested whether sponging can be predicted by mitochondrial coding genes and whether these genes are under selection. In 29 spongers and 54 non-spongers from two study sites, the non-coding haplotype at the HVRI locus was a significant predictor of sponging, whereas the coding mitochondrial genes were not. There was no evidence of selection in the investigated genes. Our study shows that mitochondrial gene variation is unlikely to be a viable alternative to cultural transmission as a primary driver of tool use in dolphin

Phenotypic matching by spot pattern potentially mediates female giraffe social associations

Animal color pattern is a phenotypic trait that may mediate assortative mixing (also known as homophily), whereby similar looking individuals have stronger social associations. Masai giraffe (Giraffa camelopardalis tippelskirchi) coat spot patterns show high variation and some spot traits appear to be heritable. Giraffes also have high visual acuity, which may facilitate intraspecific communication and recognition based on spot patterns. Giraffe groupings are dynamic, merging and splitting throughout the day, but females form long-term associations. We predicted that adult female giraffes show stronger associations with other females that have similar spot pattern traits. We quantified the spot pattern characteristics of 399 adult female Masai giraffes and determined the pattern similarity among pairs (dyads) in their social network. We then tested for an association between coat pattern similarity (spot size, shape, and orientation) and dyadic association strength, and quantified assortative mixing. The strength of social associations was positively correlated with similarity in spot shape. Our results are compatible with assortativity by coat patterns that are similar between mother and offspring, potentially reflecting an effect of relatedness on both pattern similarity and female social associations. These results offer evidence that spot pattern could function as a visual cue for intraspecific communication and kin or individual recognition in a fission-fusion species

Sawja: Static Analysis Workshop for Java

Static analysis is a powerful technique for automatic verification of programs but raises major engineering challenges when developing a full-fledged analyzer for a realistic language such as Java. This paper describes the Sawja library: a static analysis framework fully compliant with Java 6 which provides OCaml modules for efficiently manipulating Java bytecode programs. We present the main features of the library, including (i) efficient functional data-structures for representing program with implicit sharing and lazy parsing, (ii) an intermediate stack-less representation, and (iii) fast computation and manipulation of complete programs

Transition state theory demonstrated at the micron scale with out-of-equilibrium transport in a confined environment

International audienceTransition state theory (TST) provides a simple interpretation of many thermally activated processes. It applies successfully on timescales and length scales that differ several orders of magnitude: to chemical reactions, breaking of chemical bonds, unfolding of proteins and RNA structures and polymers crossing entropic barriers. Here we apply TST to out-of-equilibrium transport through confined environments: the thermally activated translocation of single DNA molecules over an entropic barrier helped by an external force field. Reaction pathways are effectively one dimensional and so long that they are observable in a microscope. Reaction rates are so slow that transitions are recorded on video. We find sharp transition states that are independent of the applied force, similar to chemical bond rupture, as well as transition states that change location on the reaction pathway with the strength of the applied force. The states of equilibrium and transition are separated by micrometres as compared with angstroms/nanometres for chemical bonds