Occurrence Of Adaptation Research Articles

Fatigue-Related and Timescale-Dependent Changes in Individual Movement Patterns Identified Using Support Vector Machine.

The scientific and practical fields—especially high-performance sports—increasingly request a stronger focus be placed on individual athletes in human movement science research. Machine learning methods have shown efficacy in this context by identifying the unique movement patterns of individuals and distinguishing their intra-individual changes over time. The objective of this investigation is to analyze biomechanically described movement patterns during the fatigue-related accumulation process within a single training session of a high number of repeated executions of a ballistic sports movement—specifically, the frontal foot kick (mae-geri) in karate—in expert athletes. The two leading research questions presented for consideration are (1) Can characteristics of individual movement patterns be observed throughout the entire training session despite continuous changes, i.e., even as fatigue-related processes increase? and (2) How do intra-individual movement patterns change as fatigue-related processes increase throughout a training session? Sixteen expert karatekas performed 606 frontal foot kicks directed toward an imaginary target. The kicks were performed in nine sets at 80% (K-80) of the self-experienced maximal intensity. In addition, six kicks at maximal intensity (K-100) were performed after each of the nine sets. Between the sets, the participants took a 90-s break. Three-dimensional full-body kinematic data of all kicks were recorded with 10 infrared cameras. The normalized waveforms of nine upper- and lower-body joint angles were classified using a supervised machine learning method (support vector machine). The results of the classification revealed a disjunct distinction between the kinematic movement patterns of individual athletes. The identification of unique movement patterns of individual athletes was independent of the intensity and the degree of fatigue-related processes. In other words, even with the accumulation of fatigue-related processes, the unique movement patterns of an individual athlete can be clearly identified. During the training session, changes in intra-individual movement patterns could also be detected, indicating the occurrence of adaptations in individual movement patterns throughout the fatigue-related accumulation process. The results suggest that these adaptations can be modeled in terms of changes in patterns rather than increasing variance. Practical consequences are critically discussed.

Adaptation and irreversibility in microevolution

Within the framework of population genetics we consider the evolution of an asexual haploid population under the effect of a rapidly varying natural selection (microevolution). We focus on the case in which the environment exerting selection changes stochastically. We derive the effective genotype and fitness dynamics on the slower timescales at which the relevant genetic modifications take place. We find that, despite the fast environmental switches, the population manages to adapt on the fast timescales yielding a finite positive contribution to the fitness. However, such contribution is balanced by the continuous loss in fitness due to the varying selection so that the statistics of the global fitness can be described neglecting the details of the fast environmental process. The occurrence of adaptation on fast timescales would be undetectable if one were to consider only the effective genotype and fitness dynamics on the slow timescales. We therefore propose an experimental observable to detect it.

Pulse ejection presentation system synchronized with breathing

AbstractTrials on the transmission of olfactory information together with audio and visual information are currently being conducted in the multimedia field. However, continuous emission of scents in high concentrations creates problems of human adaptation and remnant odors in the air. To overcome such problems we developed an olfactory display in conjunction with Canon Inc. This display has high emission control in the inkjet so that it can provide stable pulse emission of scents. Humans catch a scent when they breathe in and inhale small molecules in air. Therefore, it is important that the timing of scent presentation be synchronized with human breathing. We also developed a breath sensor which detects human breathing‐in (inspiration). In this study, we combined the olfactory display with the breath sensor to make a pulse ejection presentation system synchronized with the breath. The experimental evaluation showed that the system had a detection rate above 90%. Another evaluation was held at Keio Techno‐Mall 2007. From questionnaire results of the participants, we found that the system made the user feel a continuous sense of smell, without the occurrence of adaptation. It is expected that our system will allow olfactory information to be synchronized with audio and visual information for an arbitrary duration and at any time. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 72–78, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21086

呼吸に同期させたパルス射出提示システム

Trials on the transmission of olfactory information together with audio and visual information are currently being conducted in the multimedia field. However, continuous emission of scents in high concentrations creates problems of human adaptation and remnant odors in the air. To overcome such problems we developed an olfactory display in conjunction with Canon Inc. This display has high emission control in the inkjet so that it can provide stable pulse emission of scents. Humans catch a scent when they breathe in and inhale small molecules in air. Therefore, it is important that the timing of scent presentation be synchronized with human breathing. We also developed a breath sensor which detects human breathing-in (inspiration). In this study, we combined the olfactory display with the breath sensor to make a pulse ejection presentation system synchronized with the breath. The experimental evaluation showed that the system had a detection rate above 90%. Another evaluation was held at Keio Techno-Mall 2007. From questionnaire results of the participants, we found that the system made the user feel a continuous sense of smell, without the occurrence of adaptation. It is expected that our system will allow olfactory information to be synchronized with audio and visual information for an arbitrary duration and at any time. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 72–78, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21086

Adaptation, Ecological Impacts, and Risk Assessment: Insights from Research at Foundry Cove, Bayou Trepagnier, and Pass Fourchon

This paper takes a detailed look at the occurrence of genetic adaptations and ecological impacts at three contaminated sites (Foundry Cove, Bayou Trepagnier, Pass Fourchon) to assess the co-occurrence of adaptation and ecological impacts and the implications for risk assessment. Community-level ecological impacts were reported for all three sites. However, there was little evidence of population-level impacts (on the six populations that were also assessed for adaptation). Similarly, adaptation was found in only one of the populations. While this review provides an incomplete picture (adaptation was assessed on only a small subset of the species present and the reasons behind the lack of adaptation in the five populations remained unknown), it indicates that adaptation is uncommon even where ecological impacts are obvious. Theoretical considerations also predict that contaminants can have large impacts without resulting in an adaptation. While adaptation to a contaminant reflects an impact by that contaminant, the three case studies indicate that determining whether or not resistance has evolved does not appear to be a very efficient tool for detecting ecological impacts. Nevertheless, assessing the occurrence of adaptation does have a place in risk assessment, especially when assessing the likelihood of local extinction of a particular population

Resistance to lead and zinc in the western mosquitofish Gambusia affinis inhabiting contaminated Bayou Trepagnier

This study investigated the occurrence of adaptation to lead and zinc in the western mosquitofish Gambusia affinis inhabiting contaminated Bayou Trepagnier (Louisiana, USA). This bayou has a long history of industrial contamination. Present levels of lead and zinc in water and sediment were considerably higher in Bayou Trepagnier than in a nearby control stream. Tissue metal levels of mosquito fish were highly elevated for lead and (to a lesser extent) for zinc. Fish collected from Bayou Trepagnier and then exposed to zinc in a 96 h laboratory bioassay did not differ in their sensitivity to zinc from conspecifics collected from a control site. In contrast, Bayou Trepagnier fish did exhibit an increased resistance to lead. This difference in resistance to lead between Bayou Trepagnier fish and control fish was no longer evident when both groups of fish were kept for 34 days in the laboratory under identical conditions (in clean water). While a genetic basis of the difference in resistance between the two populations cannot be fully excluded, it does appear that the elevated lead resistance in Bayou Trepagnier mosquitofish is due to acclimation (physiological, individually-based) rather than adaptation at the population level

Studies on adaptation to adriamycin in cells pretreated with hydrogen peroxide

Various investigations have reported the occurrence in bacterial and mammalian cells of an adaptive response to the toxic effects of oxidants or agents that cause oxidation via redox reactions. In our previous study, it was shown that several cell lines pretreated with a low dose of hydrogen peroxide (H 2O 2) exhibited an adaptive response to subsequent high doses of adriamycin (ADR), whereas other cell lines did not. Based on the observation that the cell lines utilized differed in their sensitivity towards adriamycin, we undertook the present investigation with the goal of evaluating possible relationships between the levels of antioxidant enzymes and sensitivity towards adriamycin. Another aim was to determine relationships between the inducibility of these enzymes and the occurrence of adaptation. We utilized African Green monkey kidney (V 3), human embryo (CLV98), human melanoma (ME18), and Chinese hamster ovary (CHO) cell lines and experimentally developed adriamycin-resistant human melanoma (ME18/R N) and Chinese hamster ovary (CHO/R N) cell sublines. Cytotoxicity was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and trypan blue exclusion. The levels of catalase (CAT), Superoxide dismutase (SOD), and glutathione peroxidase (GPx) were determined in the same kind of experiment as that revealing the occurrence of adaptation. The rank order established for catalase activities was similar to that for sensitivity towards adriamycin. Aberrant increases in the tested enzymes were demonstrated in experimental groups of all kinds of cells. We conclude that in our cell systems catalase is a major determinant of adriamycin resistance. Whether the occurrence of the adaptive response under study is dependent on the contribution of catalase, itself. dependent on the degree of resistance to the drug, is discussed.

Monaural loudness adaption at low sensation levels in normal and impaired ears.

Monaural loudness adaptation was measured in subjects with normal hearing and in subjects with noise-induced sensori-neural hearing loss using a dichotic delayed balance procedure. Adapting stimuli were presented at two sensation levels (15 and 25 dB SL), two frequencies (500 and 4000 Hz), three durations (1, 30, and 60 sec) and two inter-stimulus intervals (10 and 400 msec) and the loudness of the terminal portion of the adapting stimuli was measured with a method of constant stimuli. No loudness adaptation occurred under any conditions for the normal subjects. Hearing-impaired subjects demonstrated small amounts of loudness adaptation, but the occurrence of adaptation did not always coincide with the frequency region of the hearing loss. There was no effect of interstimulus interval for either subject group. Subject Classification: [43]65.50, [43]65.64, [43]65.66.

The rate of development of colonies of Bacterium lactis aerogenes on agar plates containing drugs

When bacteria are plated on a solid medium containing a drug, only a fraction α ∞ , often very small, of the cells ever form colonies. α t , the fraction which have done so at time t , has been determined as a function of time, together with α ∞ , for various trained and untrained strains of bacteria in presence of a series of drugs. Bacterium lactis aerogenes (Aerobacter aerogenes) has been studied in this way in presence of brilliant green, proflavine, chloramphenicol, streptomycin, terramycin, thymol, sodium azide and isonicotinyl hydrazine: and Bact . coli mutabile in presence of chloramphenicol, and propamidine. In some of the examples the curves of α t / α ∞ , against time are clearly and obviously incompatible with the postulate that the resistant forms in the trained culture are pre-existent in the original. Separate experiments, moreover, have shown in these examples that a large concentration of non-resistant forms does not in fact delay the growth of forms already adapted. In other examples the α t / α ∞ against t curves are less sharply contrasted for the trained and untrained strains. Here, how ever, α ∞ for the trained strain may represent practically the whole population, while for the untrained strain it is 10 -6 or less. The statistical result of comparing, in attempts to estimate numbers of mutants, the average of one population with the extreme tail of another is examined. It is concluded that the a t / a ∞ relations, even in the second type of example, are as consistent with the occurrence of adaptations in competition with lethal actions on the plate as they are with the growth of mutants. The resistance of strains re-tested after isolation from resistant colonies is highly variable.

The rate of development of colonies of Bacterium lactis aerogenes on agar plates containing drugs.

When bacteria are plated on a solid medium containing a drug, only a fraction α ∞ often very small, of the cells ever form colonies, α t , the fraction which have done so at time t , has been determined as a function of time, together with α ∞ , for various trained and untrained strains of bacteria in presence of a series of drugs. Bacterium lactis aerogenes (Aerobacter aerogenes) has been studied in this way in presence of brilliant green, proflavine, chloramphenicol, streptomycin, terramycin, thymol, sodium azide and iso nicotinyl hydrazine: and Bact . coli mutabile in presence of chloramphenicol, and propamidine. In some of the examples the curves of α t / α ∞ against time are clearly and obviously incompatible with the postulate that the resistant forms in the trained culture are pre-existent in the original. Separate experiments, moreover, have shown in these examples that a large concentration of non-resistant forms does not in fact delay the growth of forms already adapted . In other examples the α t / α ∞ against t curves are less sharply contrasted for the trained and untrained strains. Here, however, α ∞ for the trained strain may represent practically the whole population, while for the untrained strain it is 10 -6 or less. The statistical result of comparing, in attempts to estimate numbers of mutants, the average of one population with the extreme tail of another is examined. It is concluded that the α t / α ∞ relations, even in the second type of example, are as consistent with the occurrence of adaptations in competition with lethal action son the plate as they are with the growth of mutants. The resistance of strains re-tested after isolation from resistant colonies is highly variable.