Plants are considered as archetypes of the ramification phenomenon but numerous elementary processes occur in the elaboration of the shaping of each species. This paper aims to identify the part ascribed to different mechanisms in the morphogenesis of a Thallophyte, the red alga Antihamnion plumula.Agonistic-antagonistic models (Bernard-Weil, 1988) can be applied to this alga whose thallus includes two different kinds of whorls, pleuridian and cladomian. In each whorl the agonistic and antagonistic effects are expressed by the full development (S) of (...) the two branches and by their symmetry rate (R) respectively. Variations in S and R show the existence of particular pleuridian whorls having an intermediary dissymmetry and a rhythmic arrangement similarly to that of the cladomian whorls. A unilateral change of the system (removal of a lateral cladome) induces a transitory destabilisation mainly manifested by the stimulating ascendant flow throughout the thallus. (shrink)

Tool use research has suffered from a lack of consistent theoretical frameworks. There is a plethora of tool use definitions and the most widespread ones are so inclusive that the behaviors that fall under them arguably do not have much in common. The situation is aggravated by the prevalence of anecdotes, which have played an undue role in the literature. In order to provide a more rigorous foundation for research and to advance our understanding of the interrelation between tool use (...) and cognition, we suggest the adoption of Fragaszy and Mangalam's (2018) tooling framework, which is characterized by the creation of a body-plus-object system that manages a mechanical interface between tool and surface. Tooling is limited to a narrower suite of behaviors than tool use, which might facilitate its neurocognitive investigation. Indeed, evidence in the literature indicates that tooling has distinct neurocognitive underpinnings not shared by other activities typically classified as tool use, at least in primates. In order to understand the extent of tooling incidences in previous research, we systematically surveyed the comprehensive tool use catalog by Shumaker et al. (2011). We identified 201 tool use submodes, of which only 81 could be classified as tooling, and the majority of the tool use examples across species were poorly supported by evidence. Furthermore, tooling appears to be phylogenetically less widespread than tool use, with the greatest variability found in the primate order. However, in order to confirm these findings and to understand the evolution and neurocognitive mechanisms of tooling, more systematic research will be required in the future, particularly with currently underrepresented taxa. (shrink)

Darwin's “mystery of mysteries,” the origin of species, is caused by the evolution of speciation phenotypes, i.e. phenotypic differences that depress gene flow between daughter species during speciation. Postmating, prezygotic (PMPZ) differentiation characterizes many closely related species causing conspecific sperm precedence (CSP), wherein a female preferentially utilizes conspecific over heterospecific sperm in fertilization. Until recently, the components of CSP have been difficult to observe and study in internally fertilizing organisms. Research into the mechanisms of CSP is now progressing rapidly with (...) the help of new innovative research tools. With the recent development of a sperm labeling system enabling distinct labels for different males, direct observations of competing male sperm within the female reproductive tract are possible, revealing multiple PMPZ phenotypes that combine to cause CSP. The discovery of mechanisms underlying CSP predicts an exciting future for studies of PMPZ speciation phenotypes and possible general principles underlying the origin of species. (shrink)

Philosophie et sciences: voila un theme difficile, central, de notre temps, ou il est necessairement question de son sens. C'est ce sens qu'interrogent, d'une facon a la fois historique et problematique, les essais du present volume. J. Merleau-Ponty questionne les rapports entre sciences et vulgarisation scientifique. J. Ladriere pose le probleme de La normativite de la pensee scientifique. J. Lambert met en evidence le probleme du Livre de la Nature chez Galilee et Kepler. P. Kerszberg confronte les structures internes de (...) la philosophie critique kantienne et de la theorie de la relativite sur la question cosmologique. M. Richir analyse L'illusion transcendantale dans la theorie cantorienne des ensembles. B. d'Espagnat et G. Hottois evoquent le problemes des rapports difficiles, aujourd'hui, entre science et philosophie. (shrink)

The development of the typical cladomothallus of the red algae Antithaminion plumula (Ellis) Le Jolis [= Pterothamnion plumula (Ellis) Nägcli], (Rhodophyceae, Ceramiales) is simulated with the help of a formal language called L-systems. Two types of uniseriate filaments are distinguished: axial filaments of cladomes with indefinite growth and branching and pleuridia with definite growth and branching. The rythmical acropetal formation of secondary axes with basitonic arrangement contrasts with the intercalary basitonic formation of pleuridia, resulting in an acrotonic arrangement within an (...) axial segment. Five types of cells and two types of cell divisions intervene in the system. In addition, for the graphical representations, some morphological particularities of A. plumula are taken into account: the curvature of axial filaments, the extension of growth zones, variable cell generation times, and segment length variability along an axis. The incidence of these variables on the generated thallus form is emphasized, pointing to the singularities of A. plumula. (shrink)

[506] Je ne m’arrêterai pas à vous entretenir, Messieurs, sur la liaison des connaissances, qui sont l’objet de chacune des quatre classes de cette Académie. Ces liaisons sont celles de toutes les sciences, et les mêmes que celles qui enchaînent les vérités, de façon qu’elles en font un tout étroitement uni en toutes ses parties. La classe de physique expérimentale, à laquelle j’ai cru devoir me vouer, me donnera lieu de vous offrir un point de vue plus particulier, en ce (...) que je vais ramener... (shrink)

[421] Pour indiquer le sujet de ce mémoire, je commencerai par rapporter ce qui m’en a fourni l’occasion. C’est la lecture de Longin et la comparaison de ce qu’il dit sur le sublime avec ce que d’autres auteurs en ont dit. Longin commence par faire souvenir son ami Terentianus du petit traité de Cecilius, qui roule sur la même matière, et du peu de satisfaction que leur a causée la lecture de cet ouvrage. Il taxe le style de Cecilius de (...) bassesse et de répondre assez mal à la dignité de son su... (shrink)

A análise da correspondência entre Espinosa e L. van Velthuysen pode ser bastante útil para aperfeiçoar nossa compreensão do Tractatus theologico-politicus e da filosofia de Espinosa em geral. Em sua correspondência, Espinosa é freqüentemente evasivo e lento para ver (ou, ao menos, para reconhecer) um ponto. É uma questão interessante como deveríamos dar conta destas deficiências em suas respostas, e sua correspondência com Velthuysen seria uma boa oportunidade para provar a perspectiva de Bennett. O artigo está dividido em três partes: (...) 1) Velthuysen antes de Espinosa e o contexto de suas críticas; 2) um exame das Cartas 42 e 43; e 3) o debate em torno do deísmo e do ateísmo. (shrink)

We use evidence from cognitive psychology and the history of science to examine the issue of the theory-ladenness of perceptual observation. This evidence shows that perception is theory-laden, but that it is only strongly theory-laden when the perceptual evidence is ambiguous or degraded, or when it requires a difficult perceptual judgment. We argue that debates about the theory-ladenness issue have focused too narrowly on the issue of perceptual experience, and that a full account of the scientific process requires an examination (...) of theory-ladenness in attention, perception, data interpretation, data production, memory, and scientific communication. We conclude that the evidence for theory-ladenness does not lead to a relativist account of scientific knowledge. (shrink)

There is increasing concern about “surveillance capitalism,” whereby for-profit companies generate value from data, while individuals are unable to resist (Zuboff 2019). Non-profits using data-enabled surveillance receive less attention. Higher education institutions (HEIs) have embraced data analytics, but the wide latitude that private, profit-oriented enterprises have to collect data is inappropriate. HEIs have a fiduciary relationship to students, not a narrowly transactional one (see Jones et al, forthcoming). They are responsible for facets of student life beyond education. In addition to (...) classrooms, learning management systems, and libraries, HEIs manage dormitories, gyms, dining halls, health facilities, career advising, police departments, and student employment. HEIs collect and use student data in all of these domains, ostensibly to understand learner behaviors and contexts, improve learning outcomes, and increase institutional efficiency through “learning analytics” (LA). ID card swipes and Wi-Fi log-ins can track student location, class attendance, use of campus facilities, eating habits, and friend groups. Course management systems capture how students interact with readings, video lectures, and discussion boards. Application materials provide demographic information. These data are used to identify students needing support, predict enrollment demands, and target recruiting efforts. These are laudable aims. However, current LA practices may be inconsistent with HEIs’ fiduciary responsibilities. HEIs often justify LA as advancing student interests, but some projects advance primarily organizational welfare and institutional interests. Moreover, LA advances a narrow conception of student interests while discounting privacy and autonomy. Students are generally unaware of the information collected, do not provide meaningful consent, and express discomfort and resigned acceptance about HEI data practices, especially for non-academic data (see Jones et al. forthcoming). The breadth and depth of student information available, combined with their fiduciary responsibility, create a duty that HEIs exercise substantial restraint and rigorous evaluation in data collection and use. (shrink)

The paper is concerned with explaining some of the principal theoretical developments in elementary particle physics and discussing the associated methodological problems both in respect of heuristics and appraisal. Particular reference is made to relativistic quantum field theory, renormalization, Feynman diagram techniques, the analytic S-matrix and the Chew — Frautschi bootstrap.

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