Only full-sibling families evolved eusociality

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. The paper by Nowak et al. has the evolution of eusociality as its title, but it is mostly about something else. It argues against inclusive fitness theory and offers an alternative modelling approach that is claimed to be more fundamental and general, but which, we believe, has no practical biological meaning for the evolution of eusociality. Nowak et al. overlook the robust empirical observation that eusociality has only arisen in clades where mothers are associated with their full-sibling offspring; that is, in families where the average relatedness of offspring to siblings is as high as to their own offspring, independent of population structure or ploidy. We believe that this omission makes the paper largely irrelevant for understanding the evolution of eusociality.     

The Triassic-Jurassic boundary in the Middle Eastern Levant: The magmatic event

The Asher Volcanism (207—189 Ma) represents a significant magmatic event, which since recent radiometric data, seem to straddle the Triassic/Jurassic boundary. Extending from the Mediterranean coast, across Galilee to Mount Hermon, the unusually thick volcanic sequence is interstratified with Late Triassic limestone and Early Jurassic shale. The event unfolded during an active phase of continental breakup in Gondwana, with the volcanism contemporaneous with the regional uplift of the Arabian Plate that caused denudation of the Triassic substratum, and sealed by a marked angular unconformity and development of laterites. A deep chasm filled with volcanics runs along an old NW-SE fault system characterizing the Arabian Plate and nearly perpendicular to the NE-SW Palmyrid aulacogen, which relates to an aborted breakaway of the Syrian promontory from mainland Gondwana. The volume of Asher volcanics may also reflect the role of volcanism in the T/J mass-extinction as proposed in 2004.     

Cross-reactive monoclonal antibodies to alcohol dehydrogenases

Three anti-horse liver alcohol dehydrogenase (HLADH) monoclonal antibodies are described. Two are specific for ADH and cross-react with class I and II enzymes from mouse, horse and Chinese hamster. They are specific for the native enzyme but do not inhibit enzyme activity except when combined at high concentration. The third antibody was isolated as a response to rabbit metallothionein. It binds metalloproteins and inhibits ADH activity.     

Parasitic Cape honeybee workers, Apis mellifera capensis, evade policing.

Relocation of the Cape honeybee, Apis mellifera capensis, by bee-keepers from southern to northern South Africa in 1990 has caused widespread death of managed African honeybee, A. m. scutellata, colonies. Apis mellifera capensis worker bees are able to lay diploid, female eggs without mating by means of automictic thelytoky (meiosis followed by fusion of two meiotic products to restore egg diploidy), whereas workers of other honeybee subspecies are able to lay only haploid, male eggs. The A. m. capensis workers, which are parasitizing and killing A. m. scutellata colonies in northern South Africa, are the asexual offspring of a single, original worker in which the small amount of genetic variation observed is due to crossing over during meiosis (P. Kryger, personal communication). Here we elucidate two principal mechanisms underlying this parasitism. Parasitic A. m. capensis workers activate their ovaries in host colonies that have a queen present (queenright colonies), and they lay eggs that evade being killed by other workers (worker policing)-the normal fate of worker-laid eggs in colonies with a queen. This unique parasitism by workers is an instance in which a society is unable to control the selfish actions of its members.     

Prediction from the regression model with two‐way error components

In this paper we extend the Baillie and Baltagi ( 1999 ) paper (Prediction from the regression model with one‐way error components. In Analysis of Panels and Limited Dependent Variables Models, Hsiao C, Lahiri K, Lee LF, Pesaran H (eds). Cambridge University Press, Cambridge, UK). In particular, we derive six predictors for the two‐way error components model, as well as their associated asymptotic mean squared error (AMSE) of multi‐step prediction. In addition, we also provide both theoretical and simulation evidence as to the relative efficiency of our six alternative predictors. The adequacy of the prediction AMSE formula is also investigated by the use of Monte Carlo methods which indicate that the ordinary optimal predictors perform well for various accuracy criteria. Copyright © 2010 John Wiley & Sons, Ltd.     

Advantages and limitations of formal expression

Testing the validity of knowledge requires formal expression of that knowledge. Formality of an expression is defined as the invariance, under changes of context, of the expression's meaning, i.e. the distinction which the expression represents. This encompasses both mathematical formalism and operational determination. The main advantages of formal expression are storability, universal communicability, and testability. They provide a selective edge in the Darwinian competition between ideas. However, formality can never be complete, as the context cannot be eliminated. Primitive terms, observation set-ups, and background conditions are inescapable parts of formal or operational definitions, that all refer to a context beyond the formal system. Heisenberg's Uncertainty Principle and Gödel's Theorem provide special cases of this more universal limitation principle. Context-dependent expressions, on the other hand, have the benefit of being more flexible, intuitive and direct, and putting less strain on memory. It is concluded that formality is not an absolute property, but a context-dependent one: different people will apply different amounts of formality in different situations or for different purposes. Some recent computational and empirical studies of formality and contexts illustrate the emerging scientific investigation of this dependence.     

Molecular spectroscopy: complexity of excited-state dynamics in DNA

Absorption of ultraviolet light by DNA is known to lead to carcinogenic mutations, but the processes between photon absorption and the photochemical reactions are poorly understood. In their study of the excited-stated dynamics of model DNA helices using femtosecond transient absorption spectroscopy, Crespo-Hernández et al. observe that the picosecond component of the transient signals recorded for the adenine-thymine oligonucleotide (dA)18.(dT)18 is close to that for (dA)18, but quite different from that for (dAdT)9.(dAdT)9; from this observation, they conclude that excimer formation limits excitation energy to one strand at a time. Here we use time-resolved fluorescence spectroscopy to probe the excited-state dynamics, which reveals the complexity of these systems and indicates that the interpretation of Crespo-Hernández et al. is an oversimplification. We also comment on the pertinence of separating base stacking and base pairing in excited-state dynamics of double helices and question the authors' assignment of the long-lived signal component found for (dA)18.(dT)18 to adenine excimers.