A note on the von Bertalanffy growth function concerning the allocation of surplus energy to reproduction

We propose an extended form of the von Bertalanffy growth function (VBGF), where the allocation of surplus energy to reproduction is considered. Any function can be used in our model to describe the ratio of energy allocation for reproduction to that for somatic growth. As an example, two models for energy allocation were derived: a step-function and a logistic function. The extended model can jointly describe growth in adult and juvenile stages. The change in growth rate between the two stages can be either gradual or steep; the latter gives a biphasic VBGF. The results of curve fitting indicated that a consideration of reproductive energy is meaningful for model extension. By controlling parameter values, our comprehensive model gives various growth curve shapes ranging from indeterminate to determinate growth. An increase in the number of parameters is unavoidable in practical applications of this new model. Additional information on reproduction will improve the reliability of model estimates

The Effect of Activities for Effective Processing in an Adventure Education Program on Participants\u27 Personal Development

The purpose of this study was to determine the effect of preplanned activities for effective processing, such as framing, debriefing, and transferring, on participant\u27s depth of reflection and personal development. Adventure education programs based on experiential learning methods had spread slowly in Japanese outdoor education. However, recent research concluded that adventure programs without constructed activities for processing affected personal growth and development. Sugerman (2000) describes that some participants are able to reflect spontaneously to understand the meaning of. the experience. Other participants are not able to reflect spontaneously about the experience and are unable to extract meaning from the experience. Activities for effective processing support participants in organizing the meaning of their experience and becoming aware of new ideas from other members. Therefore, activities for effective processing are not essential in adventure education, but they promote more effects of adventure education

Distinct Neuronal Lineages of the Ascidian Embryo Revealed by Expression of a Sodium Channel Gene

AbstractThe ascidian larva contains tubular neural tissue, one of the prominent anatomical features of the chordates. The cell-cleavage pattern and cell maps of the nervous system have been described in the ascidian larva in great detail. Cell types in the neural tube, however, have not yet been defined due to the lack of a suitable molecular marker. In the present work, we identified neuronal cells in the caudal neural tube of theHalocynthiaembryo by utilizing a voltage-gated Na+channel gene, TuNa I, as a molecular marker. Microinjection of a lineage tracer revealed that TuNa I-positive neurons in the brain and in the trunk epidermis are derived from the a-line of the eight-cell embryo, which includes cell fates to epidermal and neural tissue. On the other hand, TuNa I-positive cells in the more caudal part of the neural tissue were not stained by microinjection into the a-line. These neurons are derived from the A-line, which contains fates of notochord and muscle, but not of epidermis. Electron microscopic observation confirmed that A-line-derived neurons consist of motor neurons innervating the dorsal and ventral muscle cells. Isolated A-line blastomeres have active membrane excitability distinct from those of the a-line-derived neuronal cells after culture under cleavage arrest, suggesting that the A-line gives rise to a neuronal cell distinct from that of the a-lineage. TuNa I expression in the a-line requires signals from another cell lineage, whereas that in the A-line occurs without tight cell contact. Thus, there are at least two distinct neuronal lineages with distinct cellular behaviors in the ascidian larva: the a-line gives rise to numerous neuronal cells, including sensory cells, controlled by a mechanism similar to vertebrate neural induction, whereas A-line cells give rise to motor neurons and ependymal cells in the caudal neural tube that develop in close association with the notochord or muscle lineage, but not with the epidermal lineage

ESR Study of Radiation-induced Solid State Polymerization of Conjugated Dienes

ESR spectra of free radicals formed from isoprene, 1, 3-pentadiene and 2, 3-dimethyl-l, 3-butadiene were studied at -196°C. Free radicals were formed by several ways, i.e. electron-irradiation, reaction with HO· and CH₃· radicals and ultraviolet-irradiation at -196°C. The structure of trapped free radicals formed by electron-irradiation are quite different from that of radicals formed by radical reactions. The mechanism of radiation-induced solid state polymerization is discussed. It is concluded that the trapped free radical formed by radiation is not the propagating radical but an inactive radical end which is formed in the ionic propagation process initiated by an ion-radical