Efficiency fosters cumulative culture across species.

Recent studies in several taxa have demonstrated that animal culture can evolve to become more efficient in various contexts ranging from tool use to route learning and migration. Under recent definitions, such increases in efficiency might satisfy the core criteria of cumulative cultural evolution (CCE). However, there is not yet a satisfying consensus on the precise definition of efficiency, CCE or the link between efficiency and more complex, extended forms of CCE considered uniquely human. To bring clarity to this wider discussion of CCE, we develop the concept of efficiency by (i) reviewing recent potential evidence for CCE in animals, and (ii) clarifying a useful definition of efficiency by synthesizing perspectives found within the literature, including animal studies and the wider iterated learning literature. Finally, (iii) we discuss what factors might impinge on the informational bottleneck of social transmission, and argue that this provides pressure for learnable behaviours across species. We conclude that framing CCE in terms of efficiency casts complexity in a new light, as learnable behaviours are a requirement for the evolution of complexity. Understanding how efficiency greases the ratchet of cumulative culture provides a better appreciation of how similar cultural evolution can be between taxonomically diverse species-a case for continuity across the animal kingdom. This article is part of a discussion meeting issue 'The emergence of collective knowledge and cumulative culture in animals, humans and machines'.

The fourth dimension of tool use: temporally enduring artefacts aid primates learning to use tools.

All investigated cases of habitual tool use in wild chimpanzees and capuchin monkeys include youngsters encountering durable artefacts, most often in a supportive social context. We propose that enduring artefacts associated with tool use, such as previously used tools, partly processed food items and residual material from previous activity, aid non-human primates to learn to use tools, and to develop expertise in their use, thus contributing to traditional technologies in non-humans. Therefore, social contributions to tool use can be considered as situated in the three dimensions of Euclidean space, and in the fourth dimension of time. This notion expands the contribution of social context to learning a skill beyond the immediate presence of a model nearby. We provide examples supporting this hypothesis from wild bearded capuchin monkeys and chimpanzees, and suggest avenues for future research.

Hybrid plasmonic platforms based on silica-encapsulated gold nanorods as effective spectroscopic enhancers for Raman and fluorescence spectroscopy.

Surface-enhanced Raman scattering (SERS) nano-tags are of increasing interest in biomedical research as viable alternatives to bio-imaging techniques based on semiconductor quantum dots or fluorescent molecules. In this work, we fabricate silica-coated gold nanorods (AuNRs) encoded with two molecular labels to operate as highly effective spectroscopic nano-tags in near-infrared SERS (NIR-SERS) and surface-enhanced resonance Raman scattering combined with metal-enhanced fluorescence (SERRS-MEF), respectively. Specifically, a non-fluorescent molecule with strong affinity for a gold surface (para-aminothiophenol, p-ATP) and a common dye (Nile Blue, NB) with lower affinity have been successfully tested as NIR-SERS nano-tags under laser excitation at 785 nm. Moreover, as a result of designing AuNRs with a plasmon resonance band overlapping the electronic absorption band of the encoded NB molecule, a dual SERRS and MEF performance has been devised under resonant excitation at 633 nm. We explain this result by considering a partial desorption of NB molecules from the metal surface and their trapping into the silica shell at favorable distances to avoid quenching and enhance the fluorescence signal. Finally, we prove that the silica shell prevents the desorption or chemical transformation of p-ATP into p,p'-dimercaptoazobenzene species, as previously noticed, thus providing a highly stable SERRS signal, which is crucial for imaging applications.

Use of numerical symbols by the chimpanzee (Pan troglodytes): Cardinals, ordinals, and the introduction of zero.

An adult female chimpanzee with previous training in the use of Arabic numerals 1-9 was introduced to the meaning of "zero" in the context of three different numerical tasks. The first two were cardinal tasks where the subject was required either to select numerals corresponding to the number of items presented on a computer screen (productive use of numerals) or to match sets of the appropriate size to numerals presented as samples (receptive use). The third task addressed the ordinal meaning of the same symbols where the subject was required to respond to numerals sequentially, arranging them into an ascending series. The subject mastered the recognition of the meaning of zero in all three tasks. However, details of her usage of the symbol revealed that transfer of the meaning between different kinds of tasks was incomplete, suggesting that the level of abstraction characteristic of human numerical ability was not attained in the chimpanzee. Over the course of acquisition leading to the high levels of accuracy eventually observed, the newly introduced zero appeared to shift along the length of a continuous numerical scale toward the lower end, while confusions with 1 remained the most frequently encountered mistakes. Such patterns of error thus suggest that Ai's understanding of the meaning of zero in relation to the rest of the number symbols was not consistent with an "absence of items versus presence of items" scheme.

[Physiological role of dietary carbohydrates in diet of hungarian population. Epidemiological study]. / Fiziologicheskaia rol' i analiz struktury potrebleniia uglevodov naseleniem Vengrii.

Authors reviews--upon literature data--the metabolism of carbohydrates, with special regard to lipogenesis, which is of less importance and has no role in obesity. Out of the plasma lipids, in the case of extreme sugar consumption, only the level of triglicerides shows increase. Sugar is one but not the only factor caries. Sugar promotes the learning and remembering function of the brain and possibly, affects behaviour, too. Oligosaccharides may contribute to the favourable changes in the intestinal microflora. Carbohydrates and within them, sugars, play no unfavourable role in the development of diabetes mellitus, obesity, cardiovascular disease, when nutrition is well balanced.

Papular mucinosis and human immunodeficiency virus infection.

Cutaneous mucin deposition occurs both as an isolated phenomenon and in patients with various systemic disorders. Among these are endocrinopathies (eg, hypo- and hyperthyroidism), malignancy (mycosis fungoides), connective tissue disorders (lupus erythematosus), and infectious diseases (scleredema associated with upper respiratory tract infection). We present a case of papular mucinosis in a patient infected with the human immunodeficiency virus. This case represents the third report of these disorders coexisting.

Clinical aspects of topical retinoids.

Topical retinoids have been employed in dermatology since the 1960s to treat a wide variety of cutaneous disorders. This review focuses on three areas in which retinoids have had their greatest impact: acne vulgaris, photoaging and cutaneous neoplasia. The pharmacology of the available topical retinoids, their mechanism of action and the history of their use in these disorders are discussed.

[Report on a rare case of mitral valve aneurysm (author's transl)]. / Differentialdiagnose einer seltenen Mitralklappenveränderung.

Authors describe the mitral valve aneurysm localised in the right half of the valve dorsal leaflet as an accidental finding during autopsy of 72-years-old man. They deal with similar cases described in literature, however they point out the difference between their own case and those referred by other authors. The terms of "parachute valve" and mitral valve prolapse (resp. the syndroma of the mitral valve prolapsus) are also discussed.