1,258,539 research outputs found

    Üner Tan Syndrome: Review and Emergence of Human Quadrupedalism in Self-Organization,\ud Attractors and Evolutionary Perspectives\ud

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    The first man reported in the world literature exhibiting habitual quadrupedal locomotion was discovered by a British traveler and writer on the famous Baghdat road near Havsa/Samsun on the middle Black-Sea coast of Turkey (Childs, 1917). Interestingly, no single case with human quadrupedalism was reported in the scientific literature after Child's first description in 1917 until the first report on the Uner Tan syndrome (UTS: quadrupedalism, mental retardation, and impaired speech or no speech)in 2005 (Tan, 2005, 2006). Between 2005 and 2010, 10 families exhibiting the syndrome were discovered in Turkey with 33 cases: 14 women (42.4%) and 19 men (57.6%). Including a few cases from other countries, there were 25 men (64.1%)and 14 women (35.9%). The number of men significantly exceeded the number of women (p < .05). Genetics alone did not seem to be informative for the origins of many syndromes, including the Uner Tan syndrome. From the viewpoint of dynamical systems theory, there may not be a single factor including the neural and/or genetic codes that predetermines the emergence of the human quadrupedalism.Rather, it may involve a self-organization process, consisting of many decentralized and local interactions among neuronal, genetic, and environmental subsystems. The most remarkable characteristic of the UTS, the diagonal-sequence quadrupedalism is well developed in primates. The evolutionarily advantage of this gait is not known. However, there seems to be an evolutionarily advantage of this type of locomotion for primate evolution, with regard to the emergence of complex neural circuits with related highly complex structures. Namely, only primates with diagonal-sequence quadrupedal locomotion followed an evolution favoring larger brains, highly developed cognitive abilities with hand skills, and language, with erect posture and bipedal locomotion, creating the unity of human being. It was suggested that UTS may be considered a further example for Darwinian diseases, which may be associated with an evolutionary understanding of the disorders using evolutionary principles, such as the natural selection. On the other hand, the human quadrupedalism was proposed to be a phenotypic example of evolution of reverse, i.e., the reacquisition by derived populations of the same character states as those of ancestor populations. It was also suggested that the emergence of the human quadrupedalism may be related to self-organizing processes occurring in complex systems, which select or attract one preferred behavioral state or locomotor trait out of many possible attractor states. Concerning the locomotor patterns, the dynamical systems in brain and body of the developing child may prefer some kind of locomotion, according to interactions of the internal components and the environmental conditions, without a direct role of any causative factor(s), such as genetic or neural codes, consistent with the concept of self-organization, suggesting no single element may have a causal priority

    The parton-hadron phase transition in central nuclear collisions at the CERN SPS

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    A selection of recent data referring to Pb+Pb collisions at the SPS CERN energy of 158 GeV per nucleon is presented which might describe the state of highly excited strongly interacting matter both above and below the deconfinement to hadronization (phase) transition predicted by lattice QCD. A tentative picture emerges in which a partonic state is indeed formed in central Pb+Pb collisions which hadronizes at about T = 185 MeV, and expands its volume more than tenfold, cooling to about 120 MeV before hadronic collisions cease. We suggest further that all SPS collisions, from central S+S onward, reach that partonic phase, the maximum energy density increasing with more massive collision systems

    Quark Matter 99 summary: hadronic signals

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    I review the new data presented at QM99. The main emphasis is placed on the CERN SPS hadron production systematics concluding that the boundary between a partonic and a hadronic phase has now been located at T=180±10MeVT=180 \pm10\:MeV and ϵ1GeV\epsilon \approx 1 \:GeV per fm3fm^3

    UNERTAN SYNDROME: A CASE SERIES DEMONSTRTAING HUMAN DEVOLUTION

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    A large family with six individuals exhibiting the Unertan syndrome (UTS) was identified residing in southern Turkey. All of the individuals had mental impairments and walked on all four extremities. The intra-familial marriages suggested that the UTS is an autosomal recessive disorder. The inferior portions of the cerebellum and vermis were absent as evidenced by MRI and CT scans. The height and head circumference of those affected were within normal ranges. Barany’s test suggested normal vestibular system function. The subjects could not name objects or their close relatives. The males (n = 4) could understand simple questions, answering them with only one or two sounds. The females (n = 2) were superior to the males with respect to language skills and walking, suggesting an association between walking and speaking abilities. One male exhibited three walking patterns at the same time: quadripedal, tiptoe, and scissor walking. Another male used two walking styles: quadripedal and toe-walking. It is emphasized that there are important differences between the UTS and the disequilibrium syndrome (DES). It is suggested that the inability to walk upright in those affected with the UTS may be best explained by a disturbance in lateral-balance mechanisms. An interruption of locomotor development during the transition from quadripedality to bipedality may result in habitual walking on all four extremities and is normal in some children. Since quadripedal gait is an ancestral trait, individuals with the UTS, exhibiting a manifestation of reverse evolution in humans, may be considered an experiment of nature, useful in understanding the mechanisms underlying the transition from quadripedality to bipedality during human evolution. The proposed mutant gene or gene pool playing a role in human quadrupedality may also be responsible for human bipedality at the same time. Herein there is no intent to insult or injure, rather this report is an endeavor to better understand human beings

    Media Presence and Inner Presence: The Sense of Presence in Virtual Reality Technologies

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    Abstract. Presence is widely accepted as the key concept to be considered in any research involving human interaction with Virtual Reality (VR). Since its original description, the concept of presence has developed over the past decade to be considered by many researchers as the essence of any experience in a virtual environment. The VR generating systems comprise two main parts: a technological component and a psychological experience. The different relevance given to them produced two different but coexisting visions of presence: the rationalist and the psychological/ecological points of view. The rationalist point of view considers a VR system as a collection of specific machines with the necessity of the inclusion \ud of the concept of presence. The researchers agreeing with this approach describe the sense of presence as a function of the experience of a given medium (Media Presence). The main result of this approach is the definition of presence as the perceptual illusion of non-mediation produced by means of the disappearance of the medium from the conscious attention of the subject. At the other extreme, there \ud is the psychological or ecological perspective (Inner Presence). Specifically, this perspective considers presence as a neuropsychological phenomenon, evolved from the interplay of our biological and cultural inheritance, whose goal is the control of the human activity. \ud Given its key role and the rate at which new approaches to understanding and examining presence are appearing, this chapter draws together current research on presence to provide an up to date overview of the most widely accepted approaches to its understanding and measurement

    From a standard to an output oriented ap-proach in organic livestock farming

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    Although standards of organic livestock production clearly exceed the legal minimum requirements in many areas, the current performance in relation to animal health and product quality often does not surpass the level of conventional production and does not always meet the self-proclaimed aims and the expectations of the consumers. Thus, the standards lack efficiency in the implementa-tion of organic principles. Taking the system approach of organic farming into account, the implementation of feed back mechanisms is required to correspond to the teleological behaviour of open systems. Moreover, there is a need for a change in the paradigm from a standard to an output oriented approach to improve the level of animal health and of product quality

    Two New Cases of Uner Tan Syndrome: One Man\ud with Transition from Quadrupedalism to Bipedalism;\ud One Man with Consistent Quadrupedalism

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    Background: Uner Tan syndrome, first described in\ud 2005, consists of three main symptoms: habitual\ud locomotion on all four extremities, impaired\ud intelligence, and dysarthric or no speech. This\ud extremely rare syndrome shows an autosomal\ud recessive inheritance due to consanguineous\ud marriages between parents. In general, there is a\ud cerebellovermial hypoplasia with a mild gyral\ud simplification in the cerebral cortex. Truncal ataxia is\ud the main neurological finding, causing difficulty in\ud standing and upright walking on two legs.\ud Methods: As soon as the new cases came to light, the\ud family was visited. After taking the basic information\ud about the family members, the traditional neurological\ud examinations were performed, MRI scans of the\ud patients and of a healthy family member were taken in\ud a hospital nearest to the residence (a small village\ud near Kars, Turkey). The patients were also filmed to\ud analyze their walking patterns.\ud Results: Two individuals (case 1, 44y; case 2, 43y)\ud among six siblings from a family with consanguineous\ud parents exhibited Uner Tan syndrome, with\ud quadrupedalism, impaired intelligence, and dysarthric\ud speech. Their pedigree suggested an autosomal\ud recessive inheritance. MRI scans showed inferior\ud cerebellovermial and pontobulbar hypoplasia.\ud Case 1 did not display hypotonia, while case 2 had\ud been hypotonic for two years after birth. Case 2’s\ud hypotonia progressively disappeared, and at three\ud years old he started to sit, and could walk on all fours\ud by the age of four. Case 1 was quadrupedal for 20\ud years, and then walked upright with the aid of a\ud walking stick. Tendon reflexes were normal in case 1\ud but hyperactive in the lower extremities of case 2;\ud Babinsky was absent in case 1 but bilaterally present\ud in case 2. There was no nystagmus, no strabismus,\ud and no pes pedus in either case. Cognition was\ud severely impaired in both.\ud Conclusion: The emergence of quadrupedalism\ud during development, with a transition into bipedalism\ud in case 1, and the emergence of the quadrupedalism\ud after a full hypotonia and no locomotion in case 2,\ud were considered as examples of the processes of\ud adaptive self-organization, from the viewpoint of\ud dynamic systems theory

    Development of bipedal and quadrupedal locomotion in humans from a dynamical systems perspective

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    The first phase in the development 0f locomotion, pr,öary variability would occur in normal fetuses and infants, and those with Uner Tan syndrome. The neural networks for quadrupedal locomotion have apparently been transmitted epigenetically through many species since about 400 MYA.\ud The second phase is the neuronal selection process. During infancy, the most effective motor pattern(s) and their associated neuronal group(s) are selected through experience.\ud The third phase, secondary or adaptive variability, starts to bloom at two to three years of age and matures in adolescence. This third phase may last much longer in some patients with Uner Tan syndrome, with a considerably delay in selection of the well-balanced quadrupedal locomotion, which may emerge very late in adolescence in these cases

    A Type of Delay Feedback Control of Chaotic Dynamics in a Chaotic Neural Network

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    A chaotic neural network consisting of chaotic neurons exhibits such rich dynamical behaviors as nonperiodic associative memory. But it is difficult to distinguish the stored patterns from others, since the chaotic neural network shows chaotic wandering around the stored patterns. In order to apply the nonperiodic associative memory to information search or pattern identification, it is necessary to control chaotic dynamics. In this paper, we propose a delay feedback control method for the chaotic neural network. Computer simulation shows that, by means of the control method, the chaotic dynamics in the chaotic neural network are changed. The output sequence of the controlled network wanders around one stored pattern and its reverse pattern

    Organismic Supercategories: III. Qualitative Dynamics of Systems

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    The representation of biological systems by means of organismic supercategories, developed in previous papers, is further discussed. The different approaches to relational biology, developed by Rashevsky, Rosen and by Baianu and Marinescu, are compared with Qualitative Dynamics of Systems which was initiated by Henri Poincaré (1881). On the basis of this comparison some concrete results concerning dynamics of genetic system, development, fertilization, regeneration, analogies, and oncogenesis are derived
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