The effects of photoperiod on physical and chemical properties of broiler muscle

A series of experiments were conducted on broiler males to study the effects of photoperiod, fasting, time post-mortem and exercise on the time required for the development of rigor mortis, tenderness of breast and thigh muscle, muscle glycogen levels, and histopatho-logical characteristics of muscle. Shear values of breast muscle of birds reared on photoperiods of 24L:0D and 16L:8D were not significantly different when tested at either 2 or 20 hrs. post mortem. Excising the muscle sample from the bone immediately following slaughter resulted in higher shear values than those of muscle allowed to remain on the bone prior to cooking. This effect was not as great with respect to the thigh muscle as it was for the breast muscle and especially so for birds reared on 24L:0D. The light treatment of 24L:0D resulted in a very rapid onset of rigor mortis approximately one-half the time required by birds reared on 16L:8D. Exercising for 1 min. prior to slaughter reduced rigor time significantly in the 24L:0D group but not in the 16L:0D birds. Fasting for 24 hours prior to slaughter significantly reduced rigor time in both light treatment groups. The combination of the 24L:0D photoperiod, exercise and fasting were additive in their effects and resulted in extremely rapid onset of rigor mortis. These birds evidenced rigor on an average of 3.5 min. post slaughter. No significant effect of the two photoperiods on muscle glycogen levels could be established. Muscle glycogen was found to decrease rapidly following slaughter of the birds in both treatments. The glycogen level of muscle excised from anesthetized but living birds averaged 3-4 x of that from slaughtered birds. The myosin ATPase reaction revealed no information regarding the effects of photoperiod. Evidence of vacuolar degeneration or necrosis was present in sections of breast muscle from the 24L:0D birds but not in the 16L:8D birds. This difference was thought to be possibly related to the anaerobic glycolytic metabolism of white muscle as opposed to the oxidative aerobic metabolism of the red thigh muscle

Noise corrections to stochastic trace formulas

We review studies of an evolution operator L for a discrete Langevin equation with a strongly hyperbolic classical dynamics and a Gaussian noise. The leading eigenvalue of L yields a physically measurable property of the dynamical system, the escape rate from the repeller. The spectrum of the evolution operator L in the weak noise limit can be computed in several ways. A method using a local matrix representation of the operator allows to push the corrections to the escape rate up to order eight in the noise expansion parameter. These corrections then appear to form a divergent series. Actually, via a cumulant expansion, they relate to analogous divergent series for other quantities, the traces of the evolution operators L^n. Using an integral representation of the evolution operator L, we then investigate the high order corrections to the latter traces. Their asymptotic behavior is found to be controlled by sub-dominant saddle points previously neglected in the perturbative expansion, and to be ultimately described by a kind of trace formula.Comment: 21 pages, 4 figures,corrected typo

Cognitive ability is heritable and predicts the success of an alternative mating tactic

The research was funded through the Czech Science Foundation 457 (P505/12/G112).The ability to attract mates, acquire resources for reproduction, and successfully outcompete rivals for fertilisations may make demands on cognitive traits - the mechanisms by which an animal acquires, processes, stores, and acts upon information from its environment. Consequently, cognitive traits potentially undergo sexual selection in some mating systems. We investigated the role of cognitive traits on the reproductive performance of male rose bitterling (Rhodeus ocellatus), a freshwater fish with a complex mating system and alternative mating tactics. We quantified the learning accuracy of males and females in a spatial learning task and scored them for learning accuracy. Males were subsequently allowed to play the roles of a guarder and a sneaker in competitive mating trials, with reproductive success measured using paternity analysis. We detected a significant interaction between male mating role and learning accuracy on reproductive success, with the best performing males in maze trials showing greater reproductive success in a sneaker role than as a guarder. Using a cross-classified breeding design, learning accuracy was demonstrated to be heritable, with significant additive maternal and paternal effects. Our results imply that male cognitive traits may undergo intra-sexual selection.PostprintPeer reviewe

Computing With Coercions

This paper relates two views of the operational semantics of a language with multiple inheritance. It is shown that the introduction of explicit coercions as an interpretation for the implicit coercion of inheritance does not affect the evaluation of a program in an essential way. The result is proved by semantic means using a denotational model and a computational adequacy result to relate the operational and denotational semantics

Denotational Semantics for Subtyping Between Recursive Types

Inheritance in the form of subtyping is considered in the framework of a polymorphic type discipline with records, variants, and recursive types. We give a denotational semantics based on the paradigm that interprets subtyping as explicit coercion. The main technical result gives a coherent interpretation for a strong rule for deriving inheritances between recursive types

Electromagnetic Self-Energy Contribution to M-p-M-n and the Isovector Nucleon Magnetic Polarizability

We update the determination of the isovector nucleon electromagnetic self-energy, valid to leading order in QED. A technical oversight in the literature concerning the elastic contribution to Cottingham\u27s formula is corrected, and modern knowledge of the structure functions is used to precisely determine the inelastic contribution. We find delta M-p-n(gamma) = 1.30(03)(47) MeV. The largest uncertainty arises from a subtraction term required in the dispersive analysis, which can be related to the isovector magnetic polarizability. With plausible model assumptions, we can combine our calculation with additional input from lattice QCD to constrain this polarizability as: beta(p-n) = -0.87(85) x 10(-4) fm(3)

Nymphaea kakaduensis (Nymphaeaceae), a new species from the northern portion of the Northern Territory, Australia

Nymphaea kakaduensis C. B. Hellq., A. Leu & M. L. Moody (Nymphaeaceae) is described from Kakadu National Park, Northern Territory. This new species is endemic to the “Top End” of the Northern Territory and was formerly included in N. violacea Lehm. The distinct floral form of N. kakaduensis of having generally smaller flowers with blunt-tipped petals and different coloration than N. violacea instigated a genetic study of taxa from the region. The cpDNA trnL (UAA) - trnF (GAA) intergenic spacer region was sequenced from samples from across northern Australia and a haplotype network analysis was conducted. Plants from populations that had the distinct floral form of N. kakaduensis are found to be genetically distinct from N. violacea in northern Australia sharing 4 SNPs and a notable 23 bp indel in the cpDNA intergenic spacer region to support the morphological attributes and species designation