Face processing limitation to own species in primates: a comparative study in brown capuchins, Tonkean macaques and humans

Most primates live in social groups which survival and stability depend on individuals' abilities to create strong social relationships with other group members. The existence of those groups requires to identify individuals and to assign to each of them a social status. Individual recognition can be achieved through vocalizations but also through faces. In humans, an efficient system for the processing of own species faces exists. This specialization is achieved through experience with faces of conspecifics during development and leads to the loss of ability to process faces from other primate species. We hypothesize that a similar mechanism exists in social primates. We investigated face processing in one Old World species (genus Macaca) and in one New World species (genus Cebus). Our results show the same advantage for own species face recognition for all tested subjects. This work suggests in all species tested the existence of a common trait inherited from the primate ancestor: an efficient system to identify individual faces of own species only

Large-Scale Clonal Analysis Reveals Unexpected Complexity in Surface Ectoderm Morphogenesis

Background: Understanding the series of morphogenetic processes that underlie the making of embryo structures is a highly topical issue in developmental biology, essential for interpreting the massive molecular data currently available. In mouse embryo, long-term in vivo analysis of cell behaviours and movements is difficult because of the development in utero and the impossibility of long-term culture. Methodology/Principal Findings: We improved and combined two genetic methods of clonal analysis that together make practicable large-scale production of labelled clones. Using these methods we performed a clonal analysis of surface ectoderm (SE), a poorly understood structure, for a period that includes gastrulation and the establishment of the body plan. We show that SE formation starts with the definition at early gastrulation of a pool of founder cells that is already dorso-ventrally organized. This pool is then regionalized antero-posteriorly into three pools giving rise to head, trunk and tail. Each pool uses its own combination of cell rearrangements and mode of proliferation for elongation, despite a common clonal strategy that consists in disposing along the antero-posterior axis precursors of dorso-ventrally-oriented stripes of cells. Conclusions/Significance: We propose that these series of morphogenetic processes are organized temporally and spatially in a posterior zone of the embryo crucial for elongation. The variety of cell behaviours used by SE precursor cells indicates that these precursors are not equivalent, regardless of a common clonal origin and a common clonal strategy. Anothe

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Differentiation of high-latitude and polar marine faunas in a greenhouse world

Aim The aim was to investigate those factors that influenced the differentiation of high-latitude and polar marine faunas on both ecological and evolutionary time-scales. Can a focus on a greenhouse world provide some important clues? Location World-wide, but with particular emphasis on the evolution of Antarctic marine faunas. Time period Early Cenozoic era and present day. Major taxa studied Mollusca, especially Neogastropoda. Methods The Early Cenozoic global radiation of one of the largest extant marine clades, Neogastropoda, was examined, and detailed comparisons were made between two tropical localities and Antarctica. High- to low-latitude faunal differentiation was assessed using Sørensen's dissimilarity index, and component species in each of the three faunas were assigned to 29 families and family groups. Relative diversity distributions were fitted to these three faunas and two modern ones to assess the contrast in evenness between high- and low-latitude assemblages. Results By the Middle Eocene, a distinct high-latitude neogastropod fauna had evolved in Antarctica. In addition, the distribution of species within families in this fauna is statistically significantly less even than that in the tropics. Indeed, there is no detectable difference in the scale of this separation from that seen today. Exactly as in the modern fauna, Middle Eocene Antarctic neogastropods are dominated by a small number of trophic generalist groups. Main conclusions As the hyperdiverse Neogastropoda clade radiated globally through the Early Cenozoic, it differentiated into distinct high- and low-latitude components. The fact that it did so in a greenhouse world strongly suggests that something else besides temperature was involved in this process. The predominance of generalist feeding types in the Antarctic fossil faunas is linked to the phenomenon of a seasonally pulsed food supply, exactly as it is today. Seasonality in primary productivity may act as a fundamental control on the evolution of large-scale biodiversity pattern

Conditioning of Surfaces in Particle Accelerators

The electron cloud developing in the vacuum chambers of the LHC during the proton beam operation is responsible for heat load on the cryogenic system of the superconduct- ing magnets. The observed heat load exhibits a strong dispersion between the different LHC arcs, although identical by design. Some of them are currently close to the limit of the cryoplant capacity. Under the effect of the cloud itself, conditioning of the cop- per surface of the LHC beam pipes is expected, decreasing thus the secondary electron yield of the surface and leading to a decrease of the cloud intensity down to operation- compatible levels. Such a process seems therefore to be hindered in some parts of the LHC ring. This work aims to understand the copper conditioning processes occurring in the LHC, to unravel the origin of the heat load dispersion observed along the ring. Copper conditioning mechanisms were studied in the laboratory at room temperature by mimicking the electron cloud by an electron gun. The fundamental role of carbon, among the surface chemical components, in the reduction of the secondary electron yield during conditioning was evidenced. Studying the deconditioning, occurring while exposing a conditioned surface to air (necessary step to extract beam pipes from the LHC) allowed establishing a procedure to limit the erasing of the in-situ conditioning state of such components before the analysis of their surface in the laboratory. The surface of beam pipes extracted from a low heat load magnet were found to have similar characteristics as the ones conditioned in the laboratory. However, beam pipes extracted from a high heat load magnet exhibit cupric oxide CuO and a very low amount of surface carbon. It is demonstrated that these modifications are induced by the LHC operation and lead to a slower conditioning of these surfaces. Therefore, these modifications are currently the best candidate to explain the heat load dispersion observed in the LHC