Hunger is a psychological state that serves physiological energy homeostasis. I argue that it is a pure underived desire to eat and examine its role in homeostasis. After scene-setting explanations of homeostasis and desire, I argue that hunger is a close phenomenological match with underived desire. Then, I show why desire is an apt instrument for energy homeostasis. Finally, I argue that energy homeostasis is a multi-factorial future-regarding behavioural strategy. Hunger is a special purpose sensory (...) state that serves only to implement the strategy. Thus, it is a sensory desire. I conclude by reflecting on the credibility of this desire. (shrink)

Christopher Boorse’s Biostatistical Theory of Health has been the main contender among naturalistic accounts of health for the last 40 years. Yet, a recent criticism of this theory, presented by Elselijn Kingma, identifies a dilemma resulting from the BST’s conceptual linking of health and statistical typicality. Kingma argues that the BST either cannot accommodate the situation- specificity of many normal functions or cannot account for many situation-specific diseases. In this article, we expand upon with Daniel Hausman’s response to Kingma’s dilemma. (...) We propose that recalling Boorse’s specification that health is an intrinsic property of its bearers and explicating this intrinsic property in relation to the concept of homeostasis can illuminate how proponents of naturalistic accounts of health should deal with the situation- specificity of normal functions. We argue that beyond what Boorse and Hausman have delineated, the situation- specificity of normal function cannot be fully captured in a simple dichotomy between normal and abnormal environment or between relevant and irrelevant situations. By bringing homeostasis to the fore of the analysis of health, we set out a richer picture of what the various situations that affect living organisms’ functional performance can be. Accordingly, we provide a broader classification of these various situations which, we contend, better accounts for the main intuitions that philosophers of medicine have sought to accommodate than previous naturalistic theories of health. (shrink)

Several authors have argued that higher taxa are monophyletic homeostatic property cluster natural kinds. On the traditional definition of monophyly, this will not work: the emergence of taxon-defining homeostatic property clusters would not always correspond to unique speciation events. An alternative conception of monophyly is developed and advocated, which can accommodate the homeostatic property cluster proposal. Recent work in philosophy of science shows that it meets appropriate standards of objectivity and precision.

Antonio Damasio elabora una teoría de la mente humana y de la conducta moral a partir de su hipótesis sobre la evolución de los mecanismos de autorregulación biológicos. En ella, a la capacidad para representar relaciones organismo-mundo se le confiere un importante papel en los cambios organizacionales que emergen de los sistemas con un sistema nervioso central. Concretamente, en nuestro artículo analizamos, en primer lugar, la tesis acerca de la doble homeostasis biológica- mental que caracteriza a los agentes racionales. (...) Desde su perspectiva, la conciencia es producto y manifestación de complejos procesos del procesamiento de representaciones, los cuales favorecen la regulación no consciente. Además, para entender los procesos conscientes también es clave, según Damasio, conocer cómo la evolución de tales mecanismos está asociada con el desarrollo de áreas neuronales próximas al córtex emocional, especialmente, el giro cingulado. Los argumentos que Damasio utiliza para vincular los procesos representacionales con la particular preocupación humana por los sentimientos de los otros es la segunda cuestión que evaluamos. (shrink)

The formal properties of orbits in a plane are explored by elementary topology. The notions developed from first principles include: convex and polygonal orbits; convexity; orientation, winding number and interior; convex and star-shaped regions. It is shown that an orbit that is convex with respect to each of its interior points bounds a convex region. Also, an orbit that is convex with respect to a fixed point bounds a star-shaped region.Biological considerations that directed interest to these patterns are indicated, and (...) the implications of the prospect of higher orders of star-shapedness mentioned. (shrink)

Yan Xin Life Science Technology-Optimized Caloric Restriction (YXLST-CR) is a unique food abstinence, which suppresses appetite and sensation of hunger while maintaining physiological homeostasis. The authors review the first clinical case study on YXLST-CR, or YXLST-bigu, a 15-day, 24-hour observation in 1987 on a 21-year-old female undergoing YXLST-bigu for several months. The participant took no food or water and conducted normal physical activities. The daily records of body weight, temperature, pulse rate, blood pressure, and daily urine test results showed (...) no abnormalities. Homeostasis was maintained during YXLST-CR. The authors also report serum leptin levels in a group of individuals undergoing YXLST-CR and a control group before and after a 24-hour water-only period. The leptin level prior to the observation for the YXLST-CR group was lower than that for the control group and remained unchanged during the observation, suggesting the possibilities of an established metabolic adaptation. (shrink)

Some properties are discussed of regular polygons that may result from angular homeostatic processes in stable orbit. To characterize these homeostatic polygons we need to discuss the winding number, the sidedness (integer, fractional and irrational), multiplicity, envelopes, and density. A regular (i.e., equilateral, equiangular) polygon may be closed in one revolution about its unique center, in multiple revolutions, or not at all. A homeostatic polygon can be generated only if all vertices are included in a single polygon, which occurs if (...) and only if the number of vertices and the number of revolutions required to complete the polygon are relatively prime. For the homeostatic polygon to have a finite number of sides (without repeating itself) the angle subtended by any two successive vertices at the center must be a rational multiple of 2. Biological implications of these properties are illustrated. (shrink)

"Exhalation," a 2008 science fiction short story by Ted Chiang, virtuoso of the genre and the form, begins with a truism, refuted: "It has long been said that air (which others call argon) is the source of life. This is not in fact the case, and I engrave these words to describe how I came to understand the true source of life and, as a corollary, the means by which life will one day end" (37). The narrator's promise is so (...) alluring—knowledge of life's origin, knowledge of its expiration, and knowledge of the relation between the two—that we may be forgiven for overlooking the parenthetical. Argon amounts to less than one percent of the air breathed within Earth's atmosphere. The narrator specifies that "others call... Read More. (shrink)

We propose that sleep is linked to synaptic homeostasis. Specifically, we propose that: (1) Wakefulness is associated with synaptic potentiation in cortical circuits; (2) synaptic potentiation is tied to the homeostatic regulation of slow wave activity; (3) slow wave activity is associated with synaptic downscaling; and (4) synaptic downscaling is tied to several beneficial effects of sleep, including performance enhancement.

While purely causal theories of reference have provided a plausible account of the meanings of names and natural kind terms, they cannot handle vacuous theoretical terms. The causal homeostasis theory can but incurs other difficulties. Theories of reference that are intensional and not purely causal tend to be molecularist or holist. Holist theories threaten transtheoretic reference, whereas molecularist theories must supply a principled basis for selecting privileged meaning-determining relations between terms. The causal homeostasis theory is a two-factor molecularist (...) theory, but it fails to provide such a principled basis and collapses into holism. A naturalistic, non-foundationalist holism that deploys strategies of intertheoretic reduction and co-evolutionary pluralism can, however, yield a credible version of transtheoretic reference. (shrink)

Ubiquitin is the most phylogenetically conserved protein known. This 8,500 Da polypeptide can be covalently attached to cellular proteins as a posttranslational modification. In most cases, the addition of multiple ubiquitin adducts to a protein targets it for rapid degradation by a multisubunit protease known as the 26S proteasome. While the ubiquitin/26S proteasome pathway is responsible for the degradation of the bulk of cellular proteins during homeostasis, it may also be responsible for the rapid loss of protein during the (...) programmed death of certain cells, such as skeletal muscle during insect metamorphosis. In addition, alterations in the expression and regulation of ubiquitin may play significant roles in pathological disorders. For example, dramatic increases in ubiquitin and ubiquitin‐protein conjugates are observed in a wide variety of neurodegenerative disorders, including Alzheimer's disease. Patients suffering from the autoimmune disease systemic lupus erythematosus generate antibodies reacting with ubiquitin and ubiquitinated histones. At present, it is not known whether these changes in ubiquitin expression and regulation initiate pathological changes in these diseases or if they are altered as a consequence of these disorders. (shrink)

The idea that a human being may select at will outcomes of certain quantum events, and that this is free will, has been put forward long ago. But how can such a possibility to control quantum randomness be recombined with the necessity to obey the known statistical distributions of the laws of nature? Antoine Suarez proposes a Quantum Homeostasis Hypothesis (QHH), where this may happen during sleep or dreams. Divine providence may also be placed exactly here without violating the (...) free will of a human being, and in accordance with the necessity to follow the statistical laws of nature. God may instruct one during sleep and dreams. Apart from the Bible, this is attested to by sources in many ancient civilizations. This essay addresses this aspect of QHH in an attempt to answer the question whether data may show that our “acts of will” during dreams differ from such during a fully conscious state of mind. (shrink)

This article investigates the emergence of the concept of stress in the 1930s and outlines its changing disciplinary and conceptual frames up until 1960. Originally stress was a physiological concept applied to the hormonal regulation of the body under stressful conditions. Correlated closely with chemical research into corticosteroids for more than a decade, the stress concept finally became a topic in cognitive psychology. One reason for this shift of the concept to another discipline was the fact that the hormones previously (...) linked to the stress concept were successfully transferred from laboratory to medical practice and adopted by disciplines such as rheumatology and dermatology. Thus the stress concept was dissociated from its hormonal context and became a handy formula that allowed postindustrial society to conceive of stress as a matter of individual concern. From a physiological phenomenon stress turned into an object of psychological discourse and individual coping strategies. (shrink)

Maintaining intestinal homeostasis is a key prerequisite for a healthy gut. Recent evidence points out that microRNAs (miRNAs) act at the epicenter of the signaling networks regulating this process. The fine balance in the interaction between gut microbiota, intestinal epithelial cells, and the host immune system is achieved by constant transmission of signals and their precise regulation. Gut microbes extensively communicate with the host immune system and modulate host gene expression. On the other hand, sensing of gut microbiota by (...) the immune cells provides appropriate tolerant responses that facilitate the symbiotic relationships. While the role of many regulatory proteins, receptors and their signaling pathways in the regulation of the intestinal homeostasis is well documented, the involvement of non‐coding RNA molecules in this process has just emerged. This review discusses the most recent knowledge about the contribution of miRNAs in the regulation of the intestinal homeostasis. (shrink)

Origin of life on earth transpired once and from then on, it emerges as an endless eternal process. Matter and energy are constants of the cosmos and the hypothesis is that the origin of life is a moment when these constants intertwined or interacted. Energy from the cosmos interacted with inorganic matter to support matter with retention of this riveted energy, as energy to be circulated within the primitive channelized structures to conserve energy by the materialization of the proton (...) class='Hi'>homeostasis mechanisms developed from the obtainable inorganic matter. The driver for these processes as we now confirm, exists in the quantum world and through quantum phenomenal processes could have combined these constants to create the magic of life. Primitive earth was a chemical reactive system that triggered a macromolecular evolution by means of open thermodynamic systems, driven by cyclic gradients of temperature, electromagnetic radiation and chemical potentials which sustained life and proto-consciousness in the first life forms driven by the quantum processes. The origin of life is always an intriguing topic but the purpose for finding the cause should never be inclined towards obliterating it; for if that is the case, the further we seek, the farther it will go. (shrink)

Adult stem cell populations must coordinate their own maintenance with the generation of differentiated cell types to sustain organ physiology, in a spatially controlled manner and over long periods. Quantitative analyses of clonal dynamics have revealed that, in epithelia, homeostasis is achieved at the population rather than at the single stem cell level, suggesting that feedback mechanisms coordinate stem cell maintenance and progeny generation. In the central nervous system, however, little is known of the possible community processes underlying neural (...) stem cell maintenance. Recent work, in part based on intravital imaging made possible in the adult zebrafish, conclusively highlights that homeostasis in neural stem cell pools may rely on population asymmetry and long‐term spatiotemporal coordination of neural stem cell states and fates. These results suggest that neural stem cell assemblies in the vertebrate brain behave as self‐organized systems, such that the stem cells themselves generate their own intrinsic niche. (shrink)