Historians of science have attributed the emergence of ecology as a discipline in the late nineteenth century to the synthesis of Humboldtian botanical geography and Darwinian evolution. In this essay, I begin to explore another, largely neglected but very important dimension of this history. Using Sergei Vinogradskii’s career and scientific research trajectory as a point of entry, I illustrate the manner in which microbiologists, chemists, botanists, and plant physiologists inscribed the concept of a “cycle of life” into their investigations. Their (...) research transformed a longstanding notion into the fundamental approaches and concepts that underlay the new ecological disciplines that emerged in the 1920s. Pasteur thus joins Humboldt as a foundational figure in ecological thinking, and the broader picture that emerges of the history of ecology explains some otherwise puzzling features of that discipline – such as its fusion of experimental and natural historical methodologies. Vinogradskii’s personal “cycle of life” is also interesting as an example of the interplay between Russian and Western European scientific networks and intellectual traditions. Trained in Russia to investigate nature as a super-organism comprised of circulating energy, matter, and life; over the course of five decades – in contact with scientists and scientific discourses in France, Germany, and Switzerland – he developed a series of research methods that translated the concept of a “cycle of life” into an ecologically conceived soil science and microbiology in the 1920s and 1930s. These methods, bolstered by his authority as a founding father of microbiology, captured the attention of an international network of scientists. Vinogradskii’s conceptualization of the “cycle of life” as chemosynthesis, autotrophy, and global nutrient cycles attracted the attention of ecosystem ecologists; and his methods appealed to practitioners at agricultural experiment stations and microbiological institutes in the United States, Western Europe, and the Soviet Union. (shrink)

Providing equitable food security for a growing population while minimizing environmental impacts and enhancing resilience to climate shocks is an ongoing challenge. Here, we quantify the resource intensity, environmental impacts and nutritional output of a small (0.075 ha) low-input subsistence Mediterranean agroecological farm in a developed nation that is based on intercropping and annual crop rotation. The farm provides one individual, the proprietor, with nutritional self-sufficiency (adequate intake of an array of macro- and micro-nutrients) with limited labor, no synthetic fertilizers (...) or herbicides, and zero waste, effectively closing a full farm-table-farm cycle. We find that the agroecological farm outperforms conventional farming as practiced in the same country in terms of both lower environmental burdens, across all examined environmental metrics (63% lower on average) per kg produce, and higher nutritional score (66% higher on average). Per equal farmland, the environmental lopsidedness was even higher (79% lower than conventional farming on average), with nearly the same nutritional score (3% lower on average). Moreover, when considering total land area, which includes farmland and supporting non-agricultural lands, as well as postgate impacts and food losses, the advantage of the agroecological system over conventional farming is even more pronounced. Situated within a Mediterranean region that is undergoing rapid climate change, this food system is a unique case study of nutrition- and environment-oriented food production system. While its deployment potential is limited by lack of supportive policies, it nonetheless represents one of the most starkly bold alternatives to current food systems. (shrink)

Before a cell divides into two daughter cells, it typically doubles not only its DNA, but also its mass. Numerous studies in cells ranging from yeast to mammals have shown that cellular growth, stimulated by nutrients and/or growth factor signaling, is a prerequisite for cell cycle progression in most types of cells. The textbook view of growth‐regulated cell cycles is that growth signaling activates the transcription of G1 Cyclin genes to induce cell proliferation, and also stimulates anabolic metabolism and (...) cell growth in parallel. However, genetic knockout tests in model organisms indicate that this is not the whole story, and new studies show that additional, “smarter” mechanisms help to coordinate the cell cycle with growth itself. Here we summarize recent advances in this field, and discuss current models in which growth signaling regulates cell proliferation by targeting core cell cycle regulators via non‐transcriptional mechanisms. (shrink)

Colonists, unlike indigenous peoples, are often assumed tohave little knowledge of their environment. However, their perceptions of the environment and their knowledgeof natural resource systems have a significant impact on their farming practices. Farmers in the frontier regionof Marabá, Eastern Amazonia, understand nutrient cycling and the links between different components in farmingsystems. Diagrams drawn by farmers show very diversified systems, and farmers' knowledge of soilcharacteristics, including sub-surface features, and distribution in their localities is very detailed in comparison to pedologicalclassifications. (...) However, knowledge about nutrient cycling is very uneven, even between farmers from the same area.Generally, farmers were found to have very detailed knowledge of environmental resources, but very patchyknowledge of processes and functions underlying systems, and this conforms to evolutionary models of ecologicalknowledge. Perceptions of change in soil fertility are related to the length of settlement, and are closelylinked to the presence of forest. Overall, the majority of farmers believe they will not be able to sustain cropping in thefuture, and as forest and fallow become scarce the most feasible option will be for them to move to other areas.Farmers are more optimistic about pasture, which is viewed as a more stable system, with the key to long-termsustainability being weed control. These findings imply that a high degree of information sharing between farmers andscientists is required to establish resource management strategies and social institutions to supportsustainable development strategies at the frontier. (shrink)

This is the first book to systemize all levels of communicative behavior of phages. Phages represent the most diverse inhabitants on this planet. Until today they are completely underestimated in their number, skills and competences and still remain the dark matter of biology. Phages have serious effects on global energy and nutrient cycles. Phages actively compete for host. They can distinguish between ‘self’ and ‘non-self’. They process and evaluate available information and then modify their behaviour accordingly. These diverse (...) competences show us that this capacity to evaluate information is possible owing to communication processes within phages, between the same, related and different phage species, and between phages and non-phage organisms. This is crucial in coordinating infection strategies and recombination in phage genomes. In 22 chapters, expert contributors review current research into the varying forms of phage biocommunication and Phagetherapy. Biocommunication of Phages aims to assess the current state of research, to orient further investigations on how phages communicate with each other to coordinate their behavioral patterns, and to inspire further investigation of the role of non-phage viruses in these highly dynamic interactional networks. (shrink)

Theories of a new phase of earth history, the Anthropocene, position human world-making activity as a bio-geological force. Social interventions into earth systems have been extensive and malignant, altering the earth’s surface, atmosphere, oceans, and systems of nutrient cycling. To adapt and respond to emerging planetary dangers requires the collaboration of scholars from many different disciplines. In this paper, I argue that a coalition of the arts and sciences might draw upon György Márkus’s extensive studies of the topography of (...) ‘high’ culture. I reconstruct Márkus’s conceptual map of the arts and sciences as regions of ‘high’ cultural activity, each with their own criteria of value yet subject to an integral unity and shared ambition. Both regions of ‘high’ culture aim to create original works of significance for an engaged public. I then examine the implications of Márkus’s claim that the classical vocation of robust, public-oriented culture has run aground. The field of problems that this paper traverses are not the ecological crises of the Anthropocene per se. I attend rather to Márkus’s account of the neoliberal erosion of cultural infrastructure where democratic publics might engage with such problems. (shrink)

Theories of a new phase of earth history, the Anthropocene, position human world-making activity as a bio-geological force. Social interventions into earth systems have been extensive and malignant, altering the earth’s surface, atmosphere, oceans, and systems of nutrient cycling. To adapt and respond to emerging planetary dangers requires the collaboration of scholars from many different disciplines. In this paper, I argue that a coalition of the arts and sciences might draw upon György Márkus’s extensive studies of the topography of (...) ‘high’ culture. I reconstruct Márkus’s conceptual map of the arts and sciences as regions of ‘high’ cultural activity, each with their own criteria of value yet subject to an integral unity and shared ambition. Both regions of ‘high’ culture aim to create original works of significance for an engaged public. I then examine the implications of Márkus’s claim that the classical vocation of robust, public-oriented culture has run aground. The field of problems that this paper traverses are not the ecological crises of the Anthropocene per se. I attend rather to Márkus’s account of the neoliberal erosion of cultural infrastructure where democratic publics might engage with such problems. (shrink)

Microbial genome sequencing has entered a new phase, where DNA sequence information is gathered from entire microbial communities (metagenomics or environmental genomics) rather than from individual microorganisms. By providing access to the genetic material of vast numbers of organisms, most of which are organisms that have never been isolated or cultivated, a new level of insight is being gained into the diversity and extent of the microbial processes that are presently occuring in environmental communities. By extending metagenomic‐based approaches to the (...) study of very complex and methodologically recalcitrant soil environments, a recent study has found that ammonia‐oxidizing archaea are more abundant in many soils than bacteria.1 These findings not only highlight the undoubtedly critical yet unknown roles that archaea play in global nutrient cycles but illustrate the importance of genomic studies for informing us about the functional capacity of life on Earth. BioEssays 29: 11–14, 2007. © 2006 Wiley Periodicals, Inc. (shrink)

In budding yeast, commitment to meiosis is attained when meiotic cells cannot return to the mitotic cell cycle even if the triggering cue (nutrients deprivation) is withdrawn. Commitment is arrived at gradually, and different aspects of meiosis may be committed at different times. Cells become fully committed to meiosis at the end of Prophase I, long after DNA replication and just before the first meiotic division (MI). Whole‐genome gene expression analysis has shown that committed cells have a distinct and rapid (...) response to nutrients, and are not simply insulated from environmental signals. Thus becoming committed to meiosis is an active process. The cellular event most likely to be associated with commitment to meiosis is the separation of the duplicated spindle‐pole bodies (SPBs) and the formation of the spindle. Commitment to the mitotic cell cycle is also associated with the separation of SPBs, although it occurs in G1, before DNA replication. (shrink)

Agriculture in Western Europe has become efficient and productive but at a cost. The quality of biodiversity, soil, air, and water has been compromised. In the search for ways to ensure food security and meet the challenges of climate change, new production systems have been proposed. One of these is the transition to circular agriculture: closing the cycles of nutrients and other resources to minimise losses and end the impact on climate change. This development aims to address existing problems (...) in food production but also raises questions about animal health and welfare. Although the role animals can play in this development is not ignored, the animal welfare dimension of circular agriculture seems to be overlooked. We argue that this is a problem both for the success of circular agriculture and for the animals involved. To substantiate this claim, we analyse the background to this lack of attention, which we find in (a) the way circular agriculture is conceptualised; (b) the institutional hurdles related to the legal, political and economic context; and (c) the concept of animal welfare, which requires further innovation. By analysing these aspects, we develop stepping stones for an animal-welfare inclusive concept of circular agriculture. These stepping stones include: recognising the animal as a participant with its own interests in the innovation towards circular agriculture; using a dynamic concept of animal welfare; a concept of circularity that provides space for social values, including animal welfare; and attention to institutional innovation by improving public engagement and building trust. (shrink)

In the final analysis, sustainable agriculture must derive from applied ecology, especially the principle of the regulation of the abundance and distribution of species (and, secondarily, their activities) in space and time. Interspecific competition in natural ecosystems has its counterparts in agriculture, designed to divert greater amounts of energy, nutrients, and water into crops. Whereas natural ecosystems select for a diversity of species in communities, recent agriculture has minimized diversity in favour of vulnerable monocultures. Such systems show intrinsically less stability (...) and resilience to perturbations. Some kinds of crop rotation resemble ecological succession in that one crop prepares the land for successive crop production. Such rotations enhance soil organic processes such as decomposition and material cycling, build a nutrient capital to sustain later crop growth, and reduce the intensity of pest buildup. Species in natural communities occur at discrete points along the r-K continuum of reproductive maturity. Clearing forested land for agriculture, rotational burning practices, and replacing perennial grassland communities by cereal monocultures moves the agricultural community towards the r extreme. Plant breeders select for varieties which yield at an earlier age and lower plant biomass, effectively moving a variety towards the r type. Features of more natural landscapes, such as hedgerows, may act as physical and biological adjuncts to agricultural production. They should exist as networks in agricultural lands to be most effective. Soil is of major importance in agroecosystems, and maintaining, deliberately, its vitality and resilience to agricultural perturbations is the very basis of sustainable land use. (shrink)

The necessity of incorporating societal and environmental concerns into publicly funded agricultural initiatives in research, extension, and practice is increasingly evident. Agriculturalists are urged to acknowledge and respond to societal concerns before an insensitive and largely ill-informed urban majority assumes a dominant posture in agricultural policy. In recent history, the availability of unrealistically cheap energy encouraged the evolution of a form of commercial agriculture unfettered by sound ecological principles. At present, external, resource-intensive intervention of increasing magnitude is needed to compensate (...) for the apparent ecological instability generated by practices such as intensive cereal management or conservation tillage practices. Polarization of the enterprises of plant and animal agriculture to enable centralized, concentrate-intensive, confinement feeding has disrupted the natural cycling of nutrients and carbon in the soil, encouraged the withdrawal of perennial forages from crop rotations, and invoked a widely ramifying network of agricultural and societal problems. Solutions to these problems must evolve from a holistic and far-reaching appraisal of causes, rather than from a piecemeal approach to individual symptoms. (shrink)

Analysis of a diverse cross‐sample of plant‐insect interactions suggests that the abundance of vitamin C (L‐ascorbic acid, ascorbate or AsA) in plants influences their susceptibility to insect feeding. These effects may be mediated by AsAs roles as an essential dietary nutrient, as an antioxidant in the insect midgut, or as a substrate for plant‐derived ascorbate oxidase, which can lead to generation of toxic reactive oxygen species. Ascorbate can also influence the efficacy of plant defenses such as myrosinases and tannins, (...) and alter insects' susceptibility to natural enemies. Conversely, herbivores appear to influence both de novo synthesis and redox cycling of AsA in their host plants, thereby potentially altering the nutritional value of crops and their susceptibility to pests. The recent development of genetically modified crops with enhanced AsA content provides both an impetus and a tool set for further studies on the role of AsA in plant‐insect interactions. (shrink)

The conventional view of vitamins reflects a diverse group of small molecules that facilitate critical aspects of metabolism and prevent potentially fatal deficiency syndromes. However, vitamins also contribute to the shaping and maintenance of the human phenome over lifecycle and evolutionary timescales, enabling a degree of phenotypic plasticity that operates to allow adaptive responses that are appropriate to key periods of sensitivity (i.e., epigenetic response during prenatal development within the lifecycle or as an evolved response to environmental challenge over a (...) great many lifecycles). Individually, vitamins are important, but their effect is often based on nutrient‐nutrient (vitamin‐vitamin), nutrient‐gene (vitamin‐gene), and gene‐gene interactions, and the environmental influence of shifting geophysical cycles, as well as evolving cultural practices. These ideas will be explored within what I refer to as the “adaptive vitome (vitomics)” paradigm. (shrink)

Most aspects of agriculture in Cuba prior to 1989 were comparable to California: a high energy input, conventional agriculture (based on what the Cubans now call the “classical model”) in which little was done to protect the nation's soils from erosion, loss of fertility, salinization, and other forms of degradation. In stark contrast the new “Alternative Model,” which has been rapidly replacing the previous model since 1989, emphasizes soil conservation and rehabilitation and the general improvement of the nation's soils as (...) the key to sustaining low-input production and attainment of food security. One of the first steps in implementing the new model was the launching of an ambitious program to reclassify, evaluate, and map the nation's soils in great detail, and to interpret the maps for management of sustainable production. A main feature of this program is coordinated fertility trials to determine, for each combination of crop and soil, the minimum quantity of plant nutrients needed to produce the crop. The build up and maintenance of soil fertility and productivity is being accomplished with various organic and mineral amendments and biofertilizers, produced or mined within the country (locally, where possible) and through rational management utilizing cover crops, green manures, crop successions (intercropping and rotations), and other appropriate technologies. Rehabilitation of degraded soils, tillage reduction, reforestation, vermiculture, vermicomposting, and other forms of waste cycling are other features of the new model that are important to soil conservation and maintenance for sustainable production. (shrink)

This chapter contains sections titled: References and Further Reading.

In response to nutrient limitation, many animals, including Caenorhabditis elegans, slow or arrest their development. This process requires mechanisms that sense essential nutrients and induce appropriate responses. When faced with nutrient limitation, C. elegans can induce both short and long‐term survival strategies, including larval arrest, decreased developmental rate, and dauer formation. To select the most advantageous strategy, information from many different sensors must be integrated into signaling pathways, including target of rapamycin (TOR) and insulin, that regulate developmental progression. (...) Here, how nutrient information is sensed and integrated into developmental decisions that determine developmental rate and progression in C. elegans is reviewed. (shrink)

Food turns out to be not only the nutrient supplier for our body but also a carrier of regulatory information. Interestingly, a recent study made the discovery that some plant/food‐derived microRNAs (miRNAs) accumulate in the serum of humans or plant‐feeding animals, and regulate mammalian gene expression in a sequence‐specific manner. The authors provided striking evidence that miRNAs could function as active signaling molecules to transport information across distinct species or even kingdoms. Although the mechanism of how miRNAs are shuttled (...) between different organisms is still not well characterized, initial results point to the involvement of microvesicles and specific RNA‐transporter‐like proteins. These findings raise both speculation about the potential impact that plants may have on animal physiology at the molecular level, and an appealing possibility that food‐derived miRNAs may offer us another means to deliver necessary nutrients or therapeutics to our bodies. (shrink)

The article aims to define the management mechanism of complex, open dynamic systems with human participation. The following parts of the system life-cycle were identified and unified in the theoretical scope: general and specific compositional elements of repeating changes, marginal index boundaries, the dynamics of the compositional elements of the lifecycle, the key points of the change in the character of the index dynamics. In the practical scope, two common trends of socio-economical system life-cycle management are considered. The first trend (...) is the regulation of the comprising element ratio, which provides the increase in the duration of the maximally effective performance of a functioning system. The second trend is the regulation of the reproduction time of a new system. The systems life cycle aspects are investigated in almost all sciences and studied within many disciplines in the field of higher education. Therefore, deepening the mastery of scientific and methodological foundations of the life cycle of a complex open dynamic system is useful for any subject in everyday and practical activities. A human being – in the formation of own human capital. Families – when it is formed, the birth of children, the distribution of income and expenses. Companies – for efficient business activities. As well as local communities, local self-government bodies, public authorities and global entities within their profile activities. The results of the research provide the possibility of the development of applicable mechanisms for effectiveness and stability enhancement of managerial and entrepreneurial operation in business projects. (shrink)

The nature/nurture debate is not dead. Dichotomous views of development still underlie many fundamental debates in the biological and social sciences. Developmental systems theory offers a new conceptual framework with which to resolve such debates. DST views ontogeny as contingent cycles of interaction among a varied set of developmental resources, no one of which controls the process. These factors include DNA, cellular and organismic structure, and social and ecological interactions. DST has excited interest from a wide range of researchers, (...) from molecular biologists to anthropologists, because of its ability to integrate evolutionary theory and other disciplines without falling into traditional oppositions. The book provides historical background to DST, recent theoretical findings on the mechanisms of heredity, applications of the DST framework to behavioral development, implications of DST for the philosophy of biology, and critical reactions to DST. (shrink)

Several metabolites serve as substrates for histone modifications and communicate changes in the metabolic environment to the epigenome. Technologies such as metabolomics and proteomics have allowed us to reconstruct the interactions between metabolic pathways and histones. These technologies have shed light on how nutrient availability can have a dramatic effect on various histone modifications. This metabolism–epigenome cross talk plays a fundamental role in development, immune function, and diseases like cancer. Yet, major challenges remain in understanding the interactions between cellular (...) metabolism and the epigenome. How the levels and fluxes of various metabolites impact epigenetic marks is still unclear. Discussed herein are recent applications and the potential of systems biology methods such as flux tracing and metabolic modeling to address these challenges and to uncover new metabolic–epigenetic interactions. These systems approaches can ultimately help elucidate how nutrients shape the epigenome of microbes and mammalian cells. (shrink)

Covering interesting and varied philosophical terrain, _Cycling - Philosophy for Everyone_ explores in a fun but critical way the rich philosophical, cultural, and existential experiences that arise when two wheels are propelled by human energy. Incorporates or reflects the views of high-profile and notable past-professional cyclists and insiders such as Lennard Zinn, Scott Tinley, and Lance Armstrong Features contributions from the areas of cultural studies, kinesiology, literature, and political science as well as from philosophers Includes enlightening essays on the varieties (...) of the cycling experience, ranging from the ethical issues of success, women and cycling, environmental issues of commuting and the transformative potential of cycling for personal growth Shows how bicycling and philosophy create the perfect tandem Includes a foreword by Lennard Zinn, author and owner of Zinn Cycles Inc. (shrink)

The Influence of turbulence on nutrient fluxes towards phytoplankton cells has been previously estimated, but those studies did not take into account the intermittent nature of turbulent processes. This has been investigated here comparing the nutrient fluxes obtained using both mean and instantaneous turbulent energy dissipation rates. This approach shows that the size of cell potentially influenced by turbulence is lower than previously indicated, and that the spectral average estimate of the turbulence effect overestimates the flux. The capacity (...) of cell to use such intermittent flux is then discussed. (shrink)

Cet article s’inscrit dans la lignée de précédents travaux visant à rapprocher l’entrepreneur schumpétérien et le surhumain nietzschéen. Les deux partagent une créativité pouvant s’interpréter comme l’extériorisation d’un surcroît de force qui, dans l’optique nietzschéenne, s’assimile à la source extra-morale de l’accroissement de la vie. Reste à savoir si le cadre dans lequel ils évoluent est le même. Au-delà d’une approche historique du cycle de la conjoncture, notre hypothèse est que l’approche philosophique d’un cycle du devenir s’avère être féconde pour (...) une interprétation enrichie du cycle de la conjoncture, complétant et prolongeant ainsi notre interprétation du surhumain et de l’entrepreneur. (shrink)

The Iowa Nutrient Reduction Strategy aims to reduce nutrient loads in waterways from nonpoint sources such as farm fields. Farmers’ voluntary adoption of soil and water conservation practices is crucial for achieving NRS goals. Although the Iowa NRS has been active since 2013, farmer participation and net pollutant reductions have been insufficient. Therefore, continued efforts to understand the motivations and barriers that underlie farmers’ conservation actions in a comprehensive and integrated manner are needed to improve outreach strategies, and (...) research examining the relationships among factors such as farmers’ self-efficacy, motivations, perceived economic pressure, and soil and water conservation practices adoption in row crop production systems is needed to inform that outreach. This research employed social cognitive theory and previous research around the conceptual category of “motivations” to inform the study of relationships between the dynamic precursors and later modifiers of farmers’ adoption of in-field nutrient management Best Management Practices. Data are from the 2014–2016 Iowa Farm and Rural Life Poll. Self-efficacy, collective efficacy, stewardship motivation, crop insurance, perceived economic pressure, age, and crop acres were important predictors of adoption. This research provides innovative insights for policymaking, extension agencies, and other researchers concerning the adoption of nutrient management practices. (shrink)

Hormonal changes associated with the human menstrual cycle have been previously found to affect female mate preference, whereby women in the late follicular phase of their cycle (i.e., at higher risk of conception) prefer males displaying putative signals of underlying genetic fitness. Past research also suggests that romantic kissing is utilized in human mating contexts to assess potential mating partners. The current study examined whether women in their late follicular cycle phase place greater value on kissing at times when it (...) might help serve mate assessment functions. Using an international online questionnaire, results showed that women in the follicular phase of their menstrual cycle felt that kissing was more important at initial stages of a relationship than women in the luteal phase of their cycle. Furthermore, it was found that estimated progesterone levels were a significant negative predictor for these ratings. (shrink)

Cet ouvrage de référence est une vaste synthèse qui présente la doctrine traditionnelle des cycles développée et appliquée à notre temps. La cyclologie, ou théorie du temps cyclique, est une conception que l'on retrouve dans la plupart des sociétés archaïques. Selon cette vision, l'écoulement du temps n'est pas linéaire, l'histoire passant pour obéir éternellement à des cycles immuables amenant un retour périodique de l'humanité face aux mêmes situations, cycles dont la durée varie selon les traditions. La plus (...) répandue et la plus ancienne des conceptions cycliques est la mesure védique du temps en quatre âges, encore développée aujourd'hui dans l'hindouisme et le bouddhisme. Le cycle complet dure 12 000 ans environ et débute par un Age d'Or, période où l'homme possède la connaissance spirituelle et vit dans une harmonie parfaite. Puis continence le déclin (perte progressive de la connaissance) qui, en passant par l'Age d'Argent puis l'Age de Bronze, aboutit à l'Age de Fer (Kali Youga) où triomphent l'ignorance, l'égoïsme et le mal. Une conflagration (sous la forme d'un cataclysme cosmique, de guerres ou autre) purifie ensuite l'humanité pour permettre le commencement d'un nouveau cycle, donc d'un nouvel Age d'Or. Bien qu'elle soit en contradiction avec les doctrines judéo-chrétiennes qui véhiculent une vision linéaire du temps, de la Création et de la fin du inonde, la cyclologie s'est perpétuée jusqu'à nos jours, véhiculée par divers courants philosophiques. A l'aide de cette théorie, Jean Phaure a la vertu de nous faire comprendre que ce que nous vivons et la fin de cycle qui nous attend n'arrivent pas pour la première fois et ont déjà eu lieu avec des intensités différentes ; c'est un perpétuel recommencement. (shrink)

Wildlife populations in the northern reaches of the globe have long been observed to fluctuate or cycle periodically, with dramatic increases followed by catastrophic crashes. Focusing on the early work of Charles S. Elton, this article analyzes how investigations into population cycles shaped the development of Anglo-American animal ecology during the 1920s–1930s. Population cycling revealed patterns that challenged ideas about the “balance” of nature; stimulated efforts to quantify population data; and brought animal ecology into conversation with intellectual debates about (...) natural selection. Elton used the problem of understanding wildlife population cycles to explore a central tension in ecological thought: the relative influences of local conditions (food supply, predation) and universal forces (such as climate change and natural selection) in regulating wild animal populations. He also sought patronage and built research practices and the influential Bureau of Animal Population around questions of population regulation during the 1930s. Focusing on disease as a local population regulator that could interact with global climatic influences, Elton facilitated an interdisciplinary and population-based approach in early animal ecology. Elton created a network of epidemiologists, conservationists, pathologists and mathematicians, who contributed to population cycle research. I argue that, although these people often remained peripheral to ecology, their ideas shaped the young discipline. Particularly important were the concepts of abundance, density, and disease; and the interactions between these factors and natural selection. However, Elton’s reliance on density dependence unwittingly helped set up conditions conducive to the development of controversies in animal ecology in later years. While ecologists did not come to consensus on the ultimate causes of population cycles, this phenomenon was an important early catalyst for the development of theory and practice in animal ecology. (shrink)

This chapter contains sections titled: Child's Play Adolescent Infatuation Flourishing Adulthood Midlife Crisis Pit Stop Unreflective Maturity Maturity Cycles to Sofia (No, Not the Bulgarian Capital) Old Age Re‐Cycling Notes.

Business cycle theory is a broad and disparate field. Different schools of thought offer alternative explanations for cycles, often using different mathematical methods. This book provides academics and graduate students of economics with a compact and accessible exposition of business cycle theory since Keynes. The author places the main theories -- Keynesian economics, monetarism, new classical economics, the real business cycles theory, and new Keynesian economics -- in an historical context by presenting them in the chronological order of (...) their appearance and highlighting their differences and commonalities. He minimizes the necessary mathematical prerequisites by using a unifying mathematical approach: stochastic second-order difference equations, which is explained in detail. Throughout the book, the international dimension of business cycles is acknowledged. The theoretical results obtained are set alongside empirical facts in separate boxes. Each chapter finishes with a set of problems designed to deepen the reader's understanding of the theories presented, and further reading sections which provide access to related material. (shrink)

This study shows that double thymidine block treatment efficiently arrests the EO771 cells in the S‐phase without altering cell growth or survival. A long‐term analysis of cell behavior, using 5(6)‐carboxyfluorescein diacetate N‐succinimidyl ester (CFSE) staining, show synchronization to be stable and consistent over time. The EO771 cell line is a medullary breast‐adenocarcinoma cell line isolated from a spontaneous murine mammary tumor, and can be used to generate murine tumor implantation models. Different biological (serum or amino acid deprivation), physical (elutriation, mitotic (...) shake‐off), or chemical (colchicine, nocodazole, thymidine) treatments are widely used for cell synchronization. Of the different methods tested, the double thymidine block is the most efficient for synchronization of murine EO771 cells if a large quantity of highly synchronized cells is recommended to study functional and biochemical events occurring in specific points of cell cycle progression. (shrink)

Journal Name: Semiotica Issue: Ahead of print.

Cycles of Personal Belief by Waldo Emerson Forbes.

A range of extremely plausible moral principles turn out to generate “deontic cycling”: sets of actions wherein I have stronger reason to do B than A, C than B, and A than C. Indeed, just about anything recognizable as commonsense morality generates deontic cycling. This matters for two reasons. First, it creates a problem for the widely held view that agent-centered rankings can square consequentialism with commonsense morality. Second, it forces a choice between some deeply plausible views about rationality—wherein someone (...) cannot have stronger reason to do A than B, B than C, and C than A—and commonsense morality. (shrink)

Mixed-strategy equilibria are typically rather unstable in evolutionary game theory. “Monocyclic” games, such as Rock–Paper–Scissors, have only mixed equilibria, some of which are “stable” in the sense that sequential best replies lead to them; yet, even these games are prone to stable cycles under discrete-time simultaneous best replies, giving an unusual equilibrium-selection problem. This article analyzes such games in a random-utility setting where changing strategies is costly, and the speed of the dynamic is, thus, endogenous. The stochastically stable outcome (...) is determined by the cost of switching strategies; when switching costs are high, mixed equilibria are selected, whereas when switching costs are low, cycles are selected. (shrink)

Cell cycle arrest in M phase can be induced by the failure of a single chromosome to attach properly to the mitotic spindle. The same cell cycle checkpoint mediates M phase arrest when cells are treated with drugs that either disrupt or hyperstabilize spindle microtubules. Study of yeast mutants that fail to arrest in the presence of microtubule disruptors identified a set of genes important in this checkpoint pathway. Two recent papers report the cloning of human and Xenopus homologues of (...) one of these yeast genes, called MAD2 (for mitotic arrest deficient‐2)(1,2). Introduction of antibodies to the MAD2 protein into living mammalian cells or Xenopus egg extracts abrogates the M phase arrest induced by microtubule inhibitors. This and other recent developments suggest a model for the M phase checkpoint in which unattached kinetochores inhibit the ubiquitination of proteins whose proteolysis is necessary for chromatid separation and exit from mitosis. (shrink)

We invite systematic consideration of the metaphors of cycles and circulation as a long-term theme in the history of the life and environmental sciences and medicine. Ubiquitous in ancient religious and philosophical traditions, especially in representing the seasons and the motions of celestial bodies, circles once symbolized perfection. Over the centuries cyclic images in western medicine, natural philosophy, natural history and eventually biology gained independence from cosmology and theology and came to depend less on strictly circular forms. As potent (...) ‘canonical icons’, cycles also interacted with representations of linear and irreversible change, including arrows, arcs, scales, series and trees, as in theories of the Earth and of evolution. In modern times life cycles and reproductive cycles have often been held to characterize life, in some cases especially female life, while human efforts selectively to foster and disrupt these cycles have harnessed their productivity in medicine and agriculture. But strong cyclic metaphors have continued to link physiology and climatology, medicine and economics, and biology and manufacturing, notably through the relations between land, food and population. From the grand nineteenth-century transformations of matter to systems ecology, the circulation of molecules through organic and inorganic compartments has posed the problem of maintaining identity in the face of flux and highlights the seductive ability of cyclic schemes to imply closure where no original state was in fact restored. More concerted attention to cycles and circulation will enrich analyses of the power of metaphors to naturalize understandings of life and their shaping by practical interests and political imaginations. (shrink)

Recent high-profile corporate scandals are reminiscent of the corporate raider scandals of the 1980s, suggesting that ethical scandals may occur in waves. This article provides a framework for analysis of this question by suggesting that ethical attitudes may be cyclical about long-term secular trends. We provide some empirical evidence from previously published work for the existence of cycles as well as a potential mechanism for their propagation, namely widespread publicity about a particularly salient event, e.g., Enron. Further, we posit (...) that long-run secular trends would be affected through more deliberate, cognitive means, e.g., instruction in business ethics. We also discuss an important research implication, namely that traditional cross-sectional “book-end” studies surveying ethical attitudes at two different points in time may be unable to disentangle short-run cyclical movements from long-term secular trends. (shrink)

Two methods of dietary recording, the 24-hr recall and the weighed dietary intake methods, are considered appropriate for estimating energy and nutrient intakes in studies of human fertility. The former method gives lower estimates than the latter, although weighed intakes may underestimate true intakes. Examination of food intakes of pregnant, lactating, and non-pregnant, non-lactating New Guinean women shows their diet to be less homogeneous than is generally assumed for groups in developing countries. As a result direct observations of food (...) intake for a limited number of days are not sufficiently accurate for the estimation of intake of most of the nutrients examined. Rather the study design should reflect the variability of intakes of the nutrients and groups under consideration. (shrink)

Focal adhesions disassemble during mitosis, but surprisingly little is known about how these structures respond to other phases of the cell cycle. Three recent papers reveal unexpected results as they examine adhesions through the cell cycle. A biphasic response is detected where focal adhesions grow during S phase before disassembly begins early in G2. In M phase, activated integrins at the tips of retraction fibers anchor mitotic cells, but these adhesions lack the defining components of focal adhesions, such as talin, (...) paxillin, and zyxin. Re‐examining cell‐matrix adhesion reveals reticular adhesions, a new class of adhesion. These αVβ5 integrin‐mediated adhesions also lack conventional focal adhesion components and anchor mitotic cells to the extracellular matrix. As reviewed here, these studies present insight into how adhesion complexes vary through the cell cycle, and how unconventional adhesions maintain attachment during mitosis while providing spatial memory to guide daughter cell re‐spreading after cell division. (shrink)

The issue of mandatory cycle helmets is highly contentious. The aim of this paper is not to argue for or against legislation but to suggest criteria on which the debate should focus. This is done by attempting to answer the question: 'What criteria must be met before cycle helmet wearing is enforced?' Consideration is given to principles, precedents and consequences and four criteria are suggested. The criteria are to do with effectiveness, personal liberty, public acceptability and the promotion of the (...) public health benefits of cycling. (shrink)

It is a long-standing view that global translation varies during the cell cycle and is much lower in mitosis than in other cell-cycle phases. However, the central papers in the literature are not in agreement about the extent of downregulation in mitosis, ranging from a dramatic decrease to only a marginal reduction. Herein, it is argued that the discrepancy derives from technical challenges. Cell-cycle-dependent variations are most conveniently studied in synchronized cells, but the synchronization methods by themselves often evoke stress (...) responses that, in turn, affect translation rates. Further, it is argued that previously reported cell-cycle-dependent changes in the global translation rate to a large extent reflect responses to the synchronization methods. Recent findings strongly suggest that the global translation rate is not regulated in a cell-cycle-dependent manner. Novel techniques allowing a genome-wide analysis of translational profiles suggest that the extent and importance of selective translational regulation associated with cell-cycle transitions have been underestimated. Therefore, the main question is which messenger RNAs (mRNAs) are translated, rather than whether the global translation rate is decreased. (shrink)

Dietary guidelines are mostly issued by agrifood departments or agencies of governments, and are the result of power play between interest groups and values. They have considerable influence over food preferences and purchases of consumers. Ethical problems are at stake not only with respect to power strategies and their influence on consumers. In this paper I will consider three different types of guidelines: a nutrient oriented type, a process oriented type and a meal oriented type. In the nutrient (...) oriented guidelines healthy nutrients and food stuffs are mentioned that excel in containing one or more ‘healthy’ nutrients. Bio- and nutrition scientists and the producers of nutrients, like the sugar, dairy and animal industry, have a lot of influence in this variant. The nutrient oriented framing of food is focussed on individual health. Individuals are implicitly addressed to take responsibility for their own long term health; they have to acquire surveillance and cognitive skills in interpreting their bio data. They don’t need to acquire skills to cook. In the process oriented type, foods and ingredients are categorized according to minimal, refined and reconstituted production processes. Nutrition scientists have the last say here. Consumers do need some food skills to handle fresh products. In the meal oriented guidelines, politicians, social scientists and fresh food producers have prominent responsibilities with respect to the formulation of the guidelines and their application. Buying fresh products, preparing and eating together are the main themes. Food is framed in terms of cooking, and eating and sharing meals. Consumers have to spend time in buying fresh ingredients and cooking; they have to develop food capabilities. The formulation of dietary guidelines is not a neutral operation, but determined by controversies about framings of food and health, responsibilities and also by integrity and self-confidence of experts. It is striking that biological and nutrition scientists often proclaim to possess the final truth on the healthiness of nutrients, and heap scorn on diet gurus. They don’t care that their often incoherent recommendations cause a lot of confusion with consumers and sometimes even lack of trust. I discuss these themes in the paper and will also give some arguments why in the current situation the meal oriented type is ethically more acceptable. (shrink)

Across the world, the lives of men and women who are otherwise similarly situated tend to differ from each other systematically. Although gender disparities varywidely within and among regions, women everywhere are disproportionately vulnerable to poverty, abuse and political marginalization. This article proposes thatglobal gender disparities are caused by a network of norms, practices, policies, and institutions that include transnational as well as national elements. These interlaced and interacting factors frequently modify and sometimes even reduce gendered vulnerabilities but their overall (...) effect is to maintain and often intensify them. Women’s vulnerabilities in different areas of life mutually reinforce each other and I follow other authors in referring to such causal feedback loops as cycles of gendered vulnerability. I argue that these cycles now operate on a transnational as well as national scale and I illustrate this by discussing the examples of domestic work and sex work. If global institutional arrangements do indeed contribute to maintaining or intensifying distinctively gendered vulnerabilities, these arrangements deserve criti cal scrutiny from philosophers concerned with global justice. (shrink)

Bisphosphonates are a class of drugs which have shown good efficacy in the treatment of post‐menopausal osteoporosis, as well as a good safety profile. However, side‐effects such as risk for atypical femoral fractures (AFF) have appeared, leading to a decline in use of the drugs by many patients who would benefit from the treatment. While patient characteristics have contributed to improved understanding of risk factors, the mechanisms involved that explain AFF risk have not appeared. Recently, the possibility that the mechanism(s) (...) involved drug‐induced modification of cells of the nutrient canals of the femur and subsequent compromise in the bone matrix has been published. The present Hypothesis article builds on the concept presented earlier and expands into biomechanical considerations. An analogy of the mechanisms involved to a real‐life scenario is also presented. While this analogy has limitations, consideration of the biomechanical implications of progressive alterations to defects presented by compromised nutrient canal‐bone matrix also presents potential relationships with AFF risk. (shrink)