Development and production of a flame retardant, general purpose, pressure sensitive adhesive tape

The specification results for the finished tape properties were as follows: (1) adhesive strength (180 deg peel) on aluminum from 107 to 143 grams per centimeter (0.6 to 0.8 pounds per inch); (2) adhesive strength (180 deg peel) on stainless steel from 71 to 107 grams per centimeter (0.4 to 0.6 pounds per inch); (3) unwind resistance of 536 to 714 grams per centimeter (3 to 4 pounds per inch); (4) tensile strength minimum of 7143 grams per centimeter (40 pounds per inch); (5) elongation from 5 to 10% at break; (6) tear strength, Elmendorf from 200 to 350 grams (0.44 to 0.77 pounds); and (7) tear strength, tongue from 363 to 408 grams (0.8 to 0.9) pounds)

Experimental demonstration that offspring fathered by old males have shorter telomeres and reduced lifespans

Offspring of older parents frequently show reduced longevity, but the mechanisms driving this so-called 'Lansing effect' are unknown. While inheritance of short telomeres from older parents could underlie this effect, studies to date in different species have found mixed results, reporting positive, negative or no association between parental age and offspring telomere length (TL). However, most of the existing evidence is from non-experimental studies in which it is difficult to exclude alternative explanations such as differential survival of parents with different telomere lengths. Here we provide evidence in the zebra finch that offspring from older parents have reduced lifespans. As a first step in disentangling possible causes, we used an experimental approach to examine whether or not we could detect pre-natal paternal effects on offspring TL. We found that zebra finch embryos fathered by old males have shorter telomeres than those produced by the same mothers but with younger fathers. Since variation in embryonic TL persists into post-natal life, and early life TL is predictive of longevity in this species, this experimental study demonstrates that a paternally driven pre-natal TL reduction could at least in part underlie the reduced lifespan of offspring from older parents

The deteriorating soma and the indispensable germline: gamete senescence and offspring fitness

The idea that there is an impenetrable barrier that separates the germline and soma has shaped much thinking in evolutionary biology and in many other disciplines. However, recent research has revealed that the so-called ‘Weismann Barrier’ is leaky, and that information is transferred from soma to germline. Moreover, the germline itself is now known to age, and to be influenced by an age-related deterioration of the soma that houses and protects it. This could reduce the likelihood of successful reproduction by old individuals, but also lead to long-term deleterious consequences for any offspring that they do produce (including a shortened lifespan). Here, we review the evidence from a diverse and multidisciplinary literature for senescence in the germline and its consequences; we also examine the underlying mechanisms responsible, emphasizing changes in mutation rate, telomere loss, and impaired mitochondrial function in gametes. We consider the effect on life-history evolution, particularly reproductive scheduling and mate choice. Throughout, we draw attention to unresolved issues, new questions to consider, and areas where more research is needed. We also highlight the need for a more comparative approach that would reveal the diversity of processes that organisms have evolved to slow or halt age-related germline deterioration

Mass transfer in eccentric binaries: the new Oil-on-Water SPH technique

To measure the onset of mass transfer in eccentric binaries we have developed a two-phase SPH technique. Mass transfer is important in the evolution of close binaries, and a key issue is to determine the separation at which mass transfer begins. The circular case is well understood and can be treated through the use of the Roche formalism. To treat the eccentric case we use a newly-developed two phase system. The body of the donor star is made up from high-mass "water" particles, whilst the atmosphere is modelled with low-mass "oil" particles. Both sets of particles take part fully in SPH interactions. To test the technique we model circular mass-transfer binaries containing a 0.6 Msun donor star and a 1 Msun white dwarf; such binaries are thought to form cataclysmic variable (CV) systems. We find that we can reproduce a reasonable CV mass-transfer rate, and that our extended atmosphere gives a separation that is too large by aproximately 16%, although its pressure scale height is considerably exaggerated. We use the technique to measure the semi-major axis required for the onset of mass transfer in binaries with a mass ratio of q=0.6 and a range of eccentricities. Comparing to the value obtained by considering the instantaneous Roche lobe at pericentre we find that the radius of the star required for mass transfer to begin decreases systematically with increasing eccentricity.Comment: 9 pages, 8 figures, accepted by MNRA

Shorter juvenile telomere length is associated with higher survival to spawning in migratory Atlantic salmon

The risk of mortality associated with a long-distance migration will depend on an animal's physiological state, as well as the prevailing ecological conditions. Here we assess whether juvenile telomere length, which in endotherms has been shown to be a biomarker of physiological state and expected lifespan, predicts whether wild Atlantic salmon Salmo salar successfully complete their marine migration. Over 1800 juvenile fish were trapped, measured, PIT-tagged and a tissue biopsy taken when migrating as juveniles down-river towards the sea. Survivors of the marine phase of the life cycle were then re-trapped and re-sampled when returning to the river to spawn as sexually mature adults, 1.5-2.5 years later. Most individuals experienced a reduction in telomere length during the marine migratory phase of their life cycle. While the relative rate of telomere loss was greater in males than females, telomere loss was unrelated to growth at sea. Contrary to expectations, salmon that had the shortest telomeres at the time of the outward migration had the greatest probability of surviving through to the return migration. This effect, independent of body size, may indicate a trade-off between investment in readiness for marine life (which favours high glucocorticoid levels, known to increase telomere attrition in other vertebrate species) and investment in telomere maintenance. Survival was also significantly influenced by the seasonal timing of outward migration, with the fish migrating downstream earliest in the spring having the highest probability of return. This study reveals that telomere length is associated with survival, although in ways that contrast with patterns seen in endotherms. This illustrates that while telomeres may be universally important for chromosome protection, the potential for telomere dynamics to predict performance may vary across taxa

Does reproduction cause oxidative stress? An open question

There has been substantial recent interest in the possible role of oxidative stress as a mechanism underlying life-history trade-offs, particularly with regard to reproductive costs. Several recent papers have found no evidence that reproduction increases oxidative damage and so have questioned the basis of the hypothesis that oxidative damage mediates the reproduction–lifespan trade-off. However, we suggest here that the absence of the predicted relationships could be due to a fundamental problem in the design of all of the published empirical studies, namely a failure to manipulate reproductive effort. We conclude by suggesting experimental approaches that might provide a more conclusive test of the hypothesis

Intergenerational transfer of ageing: Parental age and offspring lifespan

The extent to which the age of parents at reproduction can affect offspring lifespan and other fitness-related traits is important in our understanding of the selective forces shaping life history evolution. In this article, the widely reported negative effects of parental age on offspring lifespan (the ‘Lansing effect’) is examined. Outlined herein are the potential routes whereby a Lansing effect can occur, whether effects might accumulate across multiple generations, and how the Lansing effect should be viewed as part of a broader framework, considering how parental age affects offspring fitness. The robustness of the evidence for a Lansing effect produced so far, potential confounding variables, and how the underlying mechanisms might best be unravelled through carefully designed experimental studies are discussed

Postnatal nutrition influences male attractiveness and promotes plasticity in male mating preferences

Poor early-life nutrition could reduce adult reproductive success by negatively affecting traits linked to sexual attractiveness such as song complexity. If so, this might favor strategic mate choice, allowing males with less complex songs to tailor their mating tactics to maximize the reproductive benefits. However, this possibility has been ignored in theoretical and empirical studies. By manipulating the micronutrient content of the diet (e.g., low or high) during the postnatal period of male zebra finches, we show for the first time (1) that males reared on a poor (low) micronutrient diet had less complex songs as adults; (2) that these males, in contrast to the high micronutrient diet group, were more selective in their mating strategies, discriminating against those females most likely to reduce their clutch size when paired with males having less complex songs; and (3) that by following different mating strategies, males reared on the contrasting diets obtained similar reproductive benefits. These results suggest that early-life dietary conditions can induce multiple and long-lasting effects on male and female reproductive traits. Moreover, the results seem to reflect a previously unreported case of adaptive plasticity in mate choice in response to a nutritionally mediated reduction in sexual attractiveness