Relation between radio-adaptive response and cell to cell communication

International Nuclear Information System (INIS)

Keiichiro Ishii

1996-01-01

Ionizing radiation has been considered to cause severe damages to DNA and do harm to cells in proportion to the dose, however low it might be. In 1984, Wolff et al. showed that human peripheral lymphocytes adapted to the low-dose radiation from 3 H-TdR added in culture medium and became resistant to the subsequent irradiation with high-doses of X-rays. This response, which is called radio-adaptive response, is also induced by X-rays and gamma-rays in human lymphocytes and Chinese hamster V79 cells. However, the mechanisms of and conditions for adaptive responses to radiation have not been clarified. With an objective of clarifying the conditions for adaptive responses of cells to radiation, we examined how the cell to cell communication is involved in the adaptive responses. We irradiated normal human embryo-derived (HE) cells and cancer cells (HeLa) in culture at high density with low-dose X-ray and examined their radio-adaptive responses by measuring the changes in sensitivity to subsequent high-dose X-ray irradiation using the Trypan Blue dye-exclusion test method. We also conducted experiments to examine the effects of Ca 2+ ions and Phorbol 12-Myristate 13-Acetate (TPA) which are supposed to be involved in cell to cell communication. (author)

Adaptive response and split-dose effect of radiation on the survival ...

Indian Academy of Sciences (India)

Unknown

In the present work, we report radioadaptive response in terms of survival of ... Group 4: mice pre-treated with conditioning dose of 0⋅5 Gy ... week in mice exposed to 8 Gy. For mice .... The adaptive response is known to remain for a few hours.

Relationship between neural response and adaptation selectivity to form and color: an ERP study

Directory of Open Access Journals (Sweden)

Ilias eRentzeperis

2012-04-01

Full Text Available Adaptation is widely used as a tool for studying selectivity to visual features. In these studies it is usually assumed that the loci of feature selective neural responses and adaptation coincide. We used an adaptation paradigm to investigate the relationship between response and adaptation selectivity in event-related potentials (ERP. ERPs were evoked by the presentation of colored Glass patterns in a form discrimination task. Response selectivities to form and, to some extent, color of the patterns were reflected in the C1 and N1 ERP components. Adaptation selectivity to color was reflected in N1 and was followed by a late (300-500 ms after stimulus onset effect of form adaptation. Thus for form, response and adaptation selectivity were manifested in non-overlapping intervals. These results indicate that adaptation and response selectivity can be associated with different processes. Therefore inferring selectivity from an adaptation paradigm requires analysis of both adaptation and neural response data.

Effects of inhibitors of protein kinase C and NO-synthase on the radiation-induced cytogenetic adaptive response in Chinese hamster cells in culture

International Nuclear Information System (INIS)

Gil'yano, N.Ya.; Bondarev, G.N.; Bikineeva, E.G.; Krasotskaya, G.I.; Noskin, L.A.

2001-01-01

The effect of the serine-threonin kinase inhibitor - staurosporine and inhibitor of NO-synthase - L-NAME on the radiation-induced adaptive response were studied in fibroblasts of Chinese hamster in culture. It is shown that staurosporine and L-NAME inhibit cytogenetic adaptive response induced by β-particles in low doses. Inhibition is not connected with radiosensitizing effect of these agents. L-NAME decreases significantly the γ-rays-induced chromosome aberration yield also. Study confirms the role of protein kinase C in induction of the adaptive response and participation of NO-synthase in this process is noticed for the first time [ru

Neoplastic transformation in vitro by low doses of ionizing radiation: Role of adaptive response and bystander effects

International Nuclear Information System (INIS)

Ko, M.; Lao, X.-Y.; Kapadia, R.; Elmore, E.; Redpath, J.L.

2006-01-01

The shape of the dose-response curve for cancer induction by low doses of ionizing radiation is of critical importance to the assessment of cancer risk at such doses. Epidemiologic analyses are limited by sensitivity to doses typically greater than 50-100 mGy for low LET radiation. Laboratory studies allow for the examination of lower doses using cancer-relevant endpoints. One such endpoint is neoplastic transformation in vitro. It is known that this endpoint is responsive to both adaptive response and bystander effects. The relative balance of these processes is likely to play an important role in determining the shape of the dose-response curve at low doses. A factor that may influence this balance is cell density at time of irradiation. The findings reported in this paper indicate that the transformation suppressive effect of low doses previously seen following irradiation of sub-confluent cultures, and attributed to an adaptive response, is reduced for irradiated confluent cultures. However, even under these conditions designed to optimize the role of bystander effects the data do not fit a linear no-threshold model and are still consistent with the notion of a threshold dose for neoplastic transformation in vitro by low LET radiation

Adaptive Response- A Universal Phenomenon for Radiological Protection

International Nuclear Information System (INIS)

Streffer, C.

2004-01-01

Predominantly with cells in vitro but also with whole animals in vivo it bas been shown that small radiation doses like other stress factors can render cells or organisms to a stage of higher radioresistance. This has been demonstrated with chromosomal aberrations gene mutation, cell transformation and survival. However, it is necessary to keep the appropriate conditions in a very stringent way. This implies radiation dose ranges, time factors and others. The adaptive response is transient and keeps for about three cell cycles or two to three days for mammalian cells. Most studies have been performed with low LET radiation. From the few data with high LET radiation it can be concluded that the adaptive response is much less or does not occur at all. Cellular and molecular studies indicate that the DNA repair is most important for the induction of adaptive response although the understanding of the mechanisms is certainly incomplete. In vivo other biological phenomena like the immune system also play a significant role. A high individual variability exists with respect to the extent of the adaptive response. No adaptive response apparently occurs with cells from individuals with repair-and immune-deficiencies. Several experiments during the prenatal development indicate that there is no or only little adaptive response during wide developmental stages in utero. Therefore it must be concluded that the adaptive response has limitations and is not a universal principle. Due to these restrictions of the validity and strength of adaptive response it is doubtful whether adaptive response can generally be applied in the practice of radiological protection. (Author) 42 refs

Adaptive response of DNA strand breaks in lymphocytes to low dose and γ-rays

International Nuclear Information System (INIS)

Du Zeji; Su Liaoyuan; Kong Xiangrong; Tian Hailin

1996-01-01

Fluorometric analysis of DNA unwinding was used to study the adaptive response of DNA strand breaks induced by low dose γ-rays and the effect of pADPRT inhibitor-3-AB on the adaptive response. The results indicated that 0.5-4 cGy γ-rays could induce adaptive response of DNA strand breaks in lymphocytes, especially at the doses of 2.0 and 4.0 cGy. This response was not obvious after 8.0 cGy γ-rays irradiation. A challenge dose of 5-20 Gy could make the response expressed, 15 Gy was the best one and 30 Gy was too high to give an adaptive response . 0.5 mM 3-AB could inhibit the response vigorously. As the concentration increased, the adaptive response could be inhibited completely

Adaptive response to ionising radiation induced by cadmium in zebrafish embryos

International Nuclear Information System (INIS)

Choi, V W Y; Ng, C Y P; Kong, M K Y; Yu, K N; Cheng, S H

2013-01-01

An adaptive response is a biological response where the exposure of cells or animals to a low priming exposure induces mechanisms that protect the cells or animals against the detrimental effects of a subsequent larger challenging exposure. In realistic environmental situations, living organisms can be exposed to a mixture of stressors, and the resultant effects due to such exposures are referred to as multiple stressor effects. In the present work we demonstrated, via quantification of apoptosis in the embryos, that embryos of the zebrafish (Danio rerio) subjected to a priming exposure provided by one environmental stressor (cadmium in micromolar concentrations) could undergo an adaptive response against a subsequent challenging exposure provided by another environmental stressor (alpha particles). We concluded that zebrafish embryos treated with 1 to 10 μM Cd at 5 h postfertilisation (hpf) for both 1 and 5 h could undergo an adaptive response against subsequent ∼4.4 mGy alpha-particle irradiation at 10 hpf, which could be interpreted as an antagonistic multiple stressor effect between Cd and ionising radiation. The zebrafish has become a popular vertebrate model for studying the in vivo response to ionising radiation. As such, our results suggested that multiple stressor effects should be carefully considered for human radiation risk assessment since the risk may be perturbed by another environmental stressor such as a heavy metal. (paper)

Pilot Study: Unique Response of Bone Tissue During an Investigation of Radio-Adaptive Effects in Mice

Science.gov (United States)

Sibonga, J. D.; Iwaniec, U.; Wu, H.

2011-01-01

PURPOSE: We obtained bone tissue to evaluate the collateral effects of experiments designed to investigate molecular mechanisms of radio-adaptation in a mouse model. Radio-adaptation describes a process by which the prior exposure to low dose radiation can protect against the toxic effect of a subsequent high dose exposure. In the radio-adaptation experiments, C57Bl/6 mice were exposed to either a Sham or a priming Low Dose (5 cGy) of Cs-137 gamma rays before being exposed to either a Sham or High Dose (6 Gy) 24 hours later. ANALYSIS: Bone tissue were obtained from two experiments where mice were sacrificed at 3 days (n=3/group, 12 total) and at 14 days (n=6/group, 24 total) following high dose exposure. Tissues were analyzed to 1) evaluate a radio-adaptive response in bone tissue and 2) describe cellular and microstructural effects for two skeletal sites with different rates of bone turnover. One tibia and one lumbar vertebrae (LV2), collected at the 3-day time-point, were analyzed by bone histomorphometry and micro-CT to evaluate the cellular response and any evidence of microarchitectural impact. Likewise, tibia and LV2, collected at the 14-day time-point, were analyzed by micro-CT alone to evaluate resulting changes to bone structure and microarchitecture. The data were analyzed by 2-way ANOVA to evaluate the effects of the priming low dose radiation, of the high dose radiation, and of any interaction between the priming low and high doses of radiation. Bone histomorphometry was performed in the cancellous bone (aka trabecular bone) compartments of the proximal tibial metaphysis and of LV2. RESULTS: Cellular Response @ 3 Days The priming Low Dose radiation decreased osteoblast-covered bone perimeter in the proximal tibia and the total cell density in the bone marrow in the LV2. High Dose radiation, regardless of prior exposure to priming dose, dramatically reduced total cell density in bone marrow of both the long bone and vertebra. However, in the proximal

Effect of randomness on multi-frequency aeroelastic responses resolved by Unsteady Adaptive Stochastic Finite Elements

International Nuclear Information System (INIS)

Witteveen, Jeroen A.S.; Bijl, Hester

2009-01-01

The Unsteady Adaptive Stochastic Finite Elements (UASFE) method resolves the effect of randomness in numerical simulations of single-mode aeroelastic responses with a constant accuracy in time for a constant number of samples. In this paper, the UASFE framework is extended to multi-frequency responses and continuous structures by employing a wavelet decomposition pre-processing step to decompose the sampled multi-frequency signals into single-frequency components. The effect of the randomness on the multi-frequency response is then obtained by summing the results of the UASFE interpolation at constant phase for the different frequency components. Results for multi-frequency responses and continuous structures show a three orders of magnitude reduction of computational costs compared to crude Monte Carlo simulations in a harmonically forced oscillator, a flutter panel problem, and the three-dimensional transonic AGARD 445.6 wing aeroelastic benchmark subject to random fields and random parameters with various probability distributions.

Cytogenetic adaptive response of mouse bone marrow cells to low level HTO

International Nuclear Information System (INIS)

Chen Deqing; Zhang Zhaoyang; Zhou Xiangyan

1993-01-01

Mice were abdominally injected with a adaptive dose of 3.7 x 10 2 -3.7 x 10 5 Bq/gbw HTO, and then exposed to a challenge dose of 1.5 Gy of 6 '0Co γ-rays. In bone marrow cells that received both the adaptive and challenge doses, the chromatid breaks are lower than expected on the basis of additivity of the effects of the individual treatment. The adaptive response induced with 3.7 x 10 3 Bq/gbw HTO is the most remarkable, but at 3.7 x 10 5 Bq/gbw the adaptive response seems to disappear. The adaptive response can be observed by exposing to 1.5 Gy γ-rays from 1 to 5 days after injection of 3.7 x 10 3 Bq/gbw HTO, which is the most obvious one to reduce chromatid breaks to 50% of expected at the 5th day, but at the 7th day to equate to expected. The frequency of chromatid breaks is gradually reduced with time after challenge dose, the maximum index number of adaptive response is 0.50 and appears at 24 hr after challenge dose

Effect of modeled microgravity on radiation-induced adaptive response of root growth in Arabidopsis thaliana

International Nuclear Information System (INIS)

Deng, Chenguang; Wang, Ting; Wu, Jingjing; Xu, Wei; Li, Huasheng; Liu, Min

2017-01-01

Highlights: • The radio-adaptive response (RAR) of A. thaliana root growth is modulated in microgravity. • The DNA damage repairs in RAR are regulated by microgravity. • The phytohormone auxin plays a regulatory role in the modulation of microgravity on RAR of root growth. - Abstract: Space particles have an inevitable impact on organisms during space missions; radio-adaptive response (RAR) is a critical radiation effect due to both low-dose background and sudden high-dose radiation exposure during solar storms. Although it is relevant to consider RAR within the context of microgravity, another major space environmental factor, there is no existing evidence as to its effects on RAR. In the present study, we established an experimental method for detecting the effects of gamma-irradiation on the primary root growth of Arabidopsis thaliana, in which RAR of root growth was significantly induced by several dose combinations. Microgravity was simulated using a two-dimensional rotation clinostat. It was shown that RAR of root growth was significantly inhibited under the modeled microgravity condition, and was absent in pgm-1 plants that had impaired gravity sensing in root tips. These results suggest that RAR could be modulated in microgravity. Time course analysis showed that microgravity affected either the development of radio-resistance induced by priming irradiation, or the responses of plants to challenging irradiation. After treatment with the modeled microgravity, attenuation in priming irradiation-induced expressions of DNA repair genes (AtKu70 and AtRAD54), and reduced DNA repair efficiency in response to challenging irradiation were observed. In plant roots, the polar transportation of the phytohormone auxin is regulated by gravity, and treatment with an exogenous auxin (indole-3-acetic acid) prevented the induction of RAR of root growth, suggesting that auxin might play a regulatory role in the interaction between microgravity and RAR of root growth.

Effect of modeled microgravity on radiation-induced adaptive response of root growth in Arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Deng, Chenguang [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Wang, Ting [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); Wu, Jingjing [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Xu, Wei [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); Li, Huasheng; Liu, Min [China Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); and others

2017-02-15

Highlights: • The radio-adaptive response (RAR) of A. thaliana root growth is modulated in microgravity. • The DNA damage repairs in RAR are regulated by microgravity. • The phytohormone auxin plays a regulatory role in the modulation of microgravity on RAR of root growth. - Abstract: Space particles have an inevitable impact on organisms during space missions; radio-adaptive response (RAR) is a critical radiation effect due to both low-dose background and sudden high-dose radiation exposure during solar storms. Although it is relevant to consider RAR within the context of microgravity, another major space environmental factor, there is no existing evidence as to its effects on RAR. In the present study, we established an experimental method for detecting the effects of gamma-irradiation on the primary root growth of Arabidopsis thaliana, in which RAR of root growth was significantly induced by several dose combinations. Microgravity was simulated using a two-dimensional rotation clinostat. It was shown that RAR of root growth was significantly inhibited under the modeled microgravity condition, and was absent in pgm-1 plants that had impaired gravity sensing in root tips. These results suggest that RAR could be modulated in microgravity. Time course analysis showed that microgravity affected either the development of radio-resistance induced by priming irradiation, or the responses of plants to challenging irradiation. After treatment with the modeled microgravity, attenuation in priming irradiation-induced expressions of DNA repair genes (AtKu70 and AtRAD54), and reduced DNA repair efficiency in response to challenging irradiation were observed. In plant roots, the polar transportation of the phytohormone auxin is regulated by gravity, and treatment with an exogenous auxin (indole-3-acetic acid) prevented the induction of RAR of root growth, suggesting that auxin might play a regulatory role in the interaction between microgravity and RAR of root growth.

Adaptive response after low level irradiation

Energy Technology Data Exchange (ETDEWEB)

Pelevina, I I; Afanasjev, G G; JaGotlib, V; Tereschenko, D G; Tronov, V A; Serebrjany, A M [Russian Academy of Sciences, Moscow (Russian Federation). Institute of Chemical Physics

1996-02-01

The experiments conducted on cultured HeLa (tissue culture) cells revealed that there is a limit of dose above which adaptive response was not observed and a limit of dose below which this response was not induced. The exposure of cells in the territories with elevated radiation background leads to genome instability which results in enhanced radiosensitivity. Investigations on the blood lymphocytes of people living in contaminated regions revealed that adaptive response was more significant in children whereas in adults there was slight increase. Acute irradiation serves as a tool revealing the changes that took place in DNA during chronic low level irradiations after Chernobyl disaster. (author).

Radio-adaptive response

International Nuclear Information System (INIS)

Ikushima, T.

1992-01-01

Knowledge about cellular events in mammalian cells exposed to low doses of ionizing radiation is meager. Recent works showed that human lymphocytes become resistant to radiation-induced chromosomal damage after exposure to low doses of ionizing radiation. Experimental evidence for radio-adaptive response (RAR) in cultured mammalian cells was obtained. Exposure to very low doses of gamma-rays or tritium beta-rays make cells less susceptible to the induction of micronuclei and sister chromatid exchanges by subsequent higher doses. Many important characteristics of the novel response suggest that RAR is a stress response resulting in the enhanced repair of chromosomal DNA damage in cell under restricted conditions. Experiments are still in progress in order to elucidate the molecular basis for RAR processes. (author). 13 refs.; 2 figs., 1 tab

Kinetics of the early adaptive response and adaptation threshold dose

International Nuclear Information System (INIS)

Mendiola C, M.T.; Morales R, P.

2003-01-01

The expression kinetics of the adaptive response (RA) in mouse leukocytes in vivo and the minimum dose of gamma radiation that induces it was determined. The mice were exposed 0.005 or 0.02 Gy of 137 Cs like adaptation and 1h later to the challenge dose (1.0 Gy), another group was only exposed at 1.0 Gy and the damage is evaluated in the DNA with the rehearsal it makes. The treatment with 0. 005 Gy didn't induce RA and 0. 02 Gy causes a similar effect to the one obtained with 0.01 Gy. The RA was show from an interval of 0.5 h being obtained the maximum expression with 5.0 h. The threshold dose to induce the RA is 0.01 Gy and in 5.0 h the biggest quantity in molecules is presented presumably that are related with the protection of the DNA. (Author)

Adaptive Queue Management with Restraint on Non-Responsive Flows

Directory of Open Access Journals (Sweden)

Lan Li

2003-12-01

Full Text Available This paper proposes an adaptive queue management scheme (adaptive RED to improve Random Early Detection (RED on restraining non-responsive flows. Due to a lack of flow control mechanism, non-responsive flows can starve responsive flows for buffer and bandwidth at the gateway. In order to solve the disproportionate resource problem, RED framework is modified in this way: on detecting when the non-responsive flows starve the queue, packet-drop intensity (Max_p in RED can be adaptively adjusted to curb non-responsive flows for resource fair-sharing, such as buffer and bandwidth fair-sharing. Based on detection of traffic behaviors, intentionally restraining nonresponsive flows is to increase the throughput and decrease the drop rate of responsive flows. Our experimental results based on adaptive RED shows that the enhancement of responsive traffic and the better sharing of buffer and bandwidth can be achieved under a variety of traffic scenarios.

Adaptive response induced by occupational exposures to ionizing radiation

International Nuclear Information System (INIS)

Barquinero, J.F.; Caballin, M.R.; Barrios, L.; Murtra, P.; Egozcue, J.; Miro, R.; Ribas, M.

1997-01-01

We have found a significant decreased sensitivity to the cytogenetic effects of ionizing radiation (IR) and bleomycin (BLM) in lymphocytes from individuals occupationally exposed to IR when compared with a control population. These results suggest that occupational exposures to IR can induce adaptive response that can be detected by a subsequent treatment by IR or by BLM. However, no correlation between the results obtained with both treatments was observed. A great heterogeneity in the frequencies of chromatid aberrations induced by BLM was observed. The study of the influence of different harvesting times showed that there was no correlation with the frequencies of chromatid breaks. Our results indicate that the use of BLM to detect adaptive response has several difficulties at the individual level. (author)

Effects of local adaptation and interspecific competition on species' responses to climate change.

Science.gov (United States)

Bocedi, Greta; Atkins, Katherine E; Liao, Jishan; Henry, Roslyn C; Travis, Justin M J; Hellmann, Jessica J

2013-09-01

Local adaptation and species interactions have been shown to affect geographic ranges; therefore, we need models of climate impact that include both factors. To identify possible dynamics of species when including these factors, we ran simulations of two competing species using an individual-based, coupled map-lattice model using a linear climatic gradient that varies across latitude and is warmed over time. Reproductive success is governed by an individual's adaptation to local climate as well as its location relative to global constraints. In exploratory experiments varying the strength of adaptation and competition, competition reduces genetic diversity and slows range change, although the two species can coexist in the absence of climate change and shift in the absence of competitors. We also found that one species can drive the other to extinction, sometimes long after climate change ends. Weak selection on local adaptation and poor dispersal ability also caused surfing of cooler-adapted phenotypes from the expanding margin backwards, causing loss of warmer-adapted phenotypes. Finally, geographic ranges can become disjointed, losing centrally-adapted genotypes. These initial results suggest that the interplay between local adaptation and interspecific competition can significantly influence species' responses to climate change, in a way that demands future research. © 2013 New York Academy of Sciences.

Relationship between adaptation and cardiovascular response to tonic cold and heat pain Adaptability to tonic pain and cardiovascular responses.

Science.gov (United States)

Devoize, L; Chalaye, P; Lafrenaye, S; Marchand, S; Dallel, R

2016-05-01

The mechanisms of adaptation to tonic pain are not elucidated. We hypothesized that the adaptability to tonic pain is related to the cardiovascular system. Twenty-six subjects received over two sessions in a random order: tonic cold (7 ± 0.2 °C) and heat pain (47.5 ± 0.5 °C) on the hand for 5 min. Pain intensity, blood pressure (BP), and heart rate (HR) were continuously monitored. Pain experience during the heat (HIT) and cold (CIT) immersion tests exhibited different average time courses, being approximated with a linear and cubic function, respectively. In each test, two groups of participants could be identified based on the time course of their tonic thermal pain: one-third of participants were pain adaptive and two-thirds non adaptive. The adaptive group exhibited higher initial pain, lower last pain, and shorter latency to peak pain than the non-adaptive one. Interestingly, some participants were adaptive to both pain stimuli, most were not. HIT as well as CIT produced a stable elevation of BP. However, BP was higher during CIT than HIT (p = 0.034). HR was also increased during CIT and HIT, but the two tests differed with respect to the time course of responses. Finally, the intensity and time course of pain rating to both HIT and CIT correlated with neither BP nor HR responses. These results suggest that individual sensitivity and adaptability to tonic thermal pain is related to the intensity of initial pain rating and the latency to peak pain but not to cardiovascular responses. © 2015 European Pain Federation - EFIC®

Understanding the role of p53 in adaptive response to radiation-induced germline mutations

International Nuclear Information System (INIS)

Langlois, N.L.; Quinn, J.S.; Somers, C.M.; Boreham, D.R.; Mitchel, R.E.J.

2003-01-01

Full text: Radiation-induced adaptive response is now a widely studied area of radiation biology. Studies have demonstrated reduced levels of radiation-induced biological damage when an 'adaptive dose' is given before a higher 'challenge dose' compared to when the challenge dose is given alone. It has been shown in some systems to be a result of inducible cellular repair systems. The adaptive response has been clearly demonstrated in many model systems, however its impact on heritable effects in the mammalian germline has never been studied. Expanded Simple Tandem Repeat (ESTR) loci have been used as markers demonstrating that induced heritable mutations in mice follow a dose-response relationship. Recent data in our laboratory show preliminary evidence of radiation-induced adaptive response suppressing germline mutations at ESTR loci in wild type mice. The frequency of heritable mutations was significantly reduced when a priming dose of 0.1 Gy was given 24 hours prior to a 1 Gy acute challenging dose. We are now conducting a follow-up study to attempt to understand the mechanism of this adaptive response. P53 is known to play a significant role in governing apoptosis, DNA repair and cancer induction. In order to determine what function p53 has in the adaptive response for heritable mutations, we have mated radiation treated Trp53+/- male mice (C57Bl) to untreated, normal females (C57Bl). Using DNA fingerprinting, we are investigating the rate of inherited radiation-induced mutations on pre- and post-meiotic radiation-treated gametocytes by examining mutation frequencies in offspring DNA. If p53 is integral in the mechanism of adaptive response, we should not see an adaptive response in radiation-induced heritable mutations in these mice. This research is significant in that it will provide insight to understanding the mechanism behind radiation-induced adaptive response in the mammalian germline

The RBE of tritium-beta exposure for the induction of the adaptive response and apoptosis; cellular defense mechanisms against the biological effects of ionizing radiation

International Nuclear Information System (INIS)

Boreham, D.R.; Bahen, M.E.; Dolling, J-A.

1997-01-01

Adaption to radiation is one of a few biological responses that has been demonstrated to occur in mammalian cells exposed to doses of ionizing radiation in the occupational exposure range. The adaptive response has been well characterized in the yeast Saccharomyces cerevisiae, although the doses required to induce the response are higher than in mammalian cells. When yeast cells are primed with sublethal doses of gamma-radiation, they subsequently undergo an adaptive response and develop resistance to radiation, heat the chemical mutagens in a time and dose dependent manner. We have used this model system to assess the relative ability of tritium-beta radiation to induce the adaptive response the examined tritium-induced radiation resistance, thermal tolerance and suppression of mutation. The results show that sublethal priming doses of tritium caused yeast cells to develop resistance to radiation, heat, and a chemical mutagen MNNG. The magnitude and kinetics of the response, per unit dose, were the same for tritium and gamma-radiation. Therefore, the relative biological effectiveness (RBE) of tritium induction of the adaptive response was about 1.0. Apoptosis is a genetically programmed cell death or cell suicide. Cells damaged by radiation can be selectively removed from the population by apoptosis and therefore eliminated as a potential cancer risk to the organism. Since we have previously shown that apoptosis is a sensitive indicator of radiation damage in human lymphocytes exposed to low doses, we have used this endpoint to investigate the potency of tritium-beta radiation. Initially, tritium was compared to X-rays for relative effectiveness at inducing apoptosis. The results showed the lymphocytes irradiated in vitro with X-rays or tritium had similar levels of apoptosis per unit dose. Therefore the relative biology effectiveness of tritium for induction of apoptosis in human lymphocytes was also about 1. In the work presented here, we have demonstrated that

Human Lung Cancer Risks from Radon – Part II – Influence from Combined Adaptive Response and Bystander Effects – A Microdose Analysis

Science.gov (United States)

Leonard, Bobby E.; Thompson, Richard E.; Beecher, Georgia C.

2010-01-01

In the prior Part I, the potential influence of the low level alpha radiation induced bystander effect (BE) on human lung cancer risks was examined. Recent analysis of adaptive response (AR) research results with a Microdose Model has shown that single low LET radiation induced charged particles traversals through the cell nucleus activates AR. We have here conducted an analysis based on what is presently known about adaptive response and the bystander effect (BE) and what new research is needed that can assist in the further evaluation human cancer risks from radon. We find that, at the UNSCEAR (2000) worldwide average human exposures from natural background and man-made radiations, the human lung receives about a 25% adaptive response protection against the radon alpha bystander damage. At the UNSCEAR (2000) minimum range of background exposure levels, the lung receives minimal AR protection but at higher background levels, in the high UNSCEAR (2000) range, the lung receives essentially 100% protection from both the radon alpha damage and also the endogenic, spontaneously occurring, potentially carcinogenic, lung cellular damage. PMID:22461760

Innate, adaptive and regulatory responses in schistosomiasis: Relationship to allergy

NARCIS (Netherlands)

Hartgers, F.C.; Smits, H.H.; Kleij, D. van der; Yazdanbakhsh, M.

2006-01-01

Helminth infections have profound effects on the immune system. Here, recent insights in the molecular interactions between schistosomes and the host are described with respect to adaptive but also with respect to innate immune responses. Furthermore, the different mechanisms of immune

Monitoring adaptive genetic responses to environmental change

DEFF Research Database (Denmark)

Hansen, M.M.; Olivieri, I.; Waller, D.M.

2012-01-01

Widespread environmental changes including climate change, selective harvesting and landscape alterations now greatly affect selection regimes for most organisms. How animals and plants can adapt to these altered environments via contemporary evolution is thus of strong interest. We discuss how...... for selection and establishing clear links between genetic and environmental change. We then review a few exemplary studies that explore adaptive responses to climate change in Drosophila, selective responses to hunting and fishing, and contemporary evolution in Daphnia using resurrected resting eggs. We...

Radio-adaptation: cellular and molecular features of a response to low levels of ionizing radiation

International Nuclear Information System (INIS)

Rigaud, O.

1998-01-01

It is well established that sublethal doses of DNA damaging agents induce protective mechanisms against a subsequent high dose treatment ; for instance, the phenomenon of radio-adaptation in the case of ionizing radiations. Since the early observation described in 1984, numerous studies have confirmed the radio-adaptive response in terms of reduction of chromosomal breaks for varied biological models in vitro and in vivo. Evidence for an adaptive response against the induction of gene mutations and the lethal effect is clearly demonstrated. This paper reviews the experimental results describing various aspects of these adaptive responses expressed on these different biological end-points. The molecular mechanism underlying radio-adaptation still remains nuclear. The development of this phenomenon requires de novo synthesis of transcripts and proteins during the time interval between the two doses. Some data are consistent with the hypotheses that these gene products would be involved in the activation of DNA repair pathways and antioxidant systems. However, a major question still remains unanswered; indeed, it is not clear whether or not the radio-adaptation could affect the estimation of cancer risk related with low level exposure to ionizing radiation, a major concern in radioprotection. Until such data are available, it is yet unwise to evoke the beneficial effects of radio-adaptation. (authors)

Cytogenetic dose-response and adaptive response in cells of ungulate species exposed to ionizing radiation

International Nuclear Information System (INIS)

Ulsh, B.A.; Miller, S.M.; Mallory, F.F.; Mitchel, R.E.J.; Morrison, D.P.; Boreham, D.R.

2004-01-01

In the studies reported here, the micronucleus assay, a common cytogenetic technique, was used to examine the dose-responses in fibroblasts from three ungulate species (white-tailed deer, woodland caribou, and Indian muntjac) exposed to high doses of ionizing radiation (1-4 Gy of 60 Co gamma radiation). This assay was also used to examine the effects of exposure to low doses (1-100 mGy) typical of what these species experience in a year from natural and anthropogenic environmental sources. An adaptive response, defined as the induction of resistance to a stressor by a prior exposure to a small 'adapting' stress, was observed after exposure to low doses. This work indicates that very small doses are protective for the endpoint examined. The same level of protection was seen at all adapting doses, including 1 radiation track per cell, the lowest possible cellular dose. These results are consistent with other studies in a wide variety of organisms that demonstrate a protective effect of low doses at both cellular and whole-organism levels. This implies that environmental regulations predicated on the idea that even the smallest dose of radiation carries a quantifiable risk of direct adverse consequences to the exposed organism require further examination. Cytogenetic assays provide affordable and feasible biological effects-based alternatives that are more biologically relevant than traditional contaminant concentration-based radioecological risk assessment

Factors influencing induction of adaptive response

International Nuclear Information System (INIS)

Misonoh, Jun; Ojima, Mitsuaki; Yonezawa, Morio

2000-01-01

Exposure to low doses of X-rays makes ICR mice resistant to subsequent sublethal irradiation and decrease mortality from hematopoietic death. Many factors, however, influence the induction of radioresistance. For instances, in ICR mice, the priming irradiation with 0.50 Gy was effective in the induction of radioresistance, when it is given at 6-week old, 2 weeks prior to subsequent sublethal irradiation. One hundred-fifty kV X-ray filtered off the soft component through 1.0 mm aluminum and 0.2 mm copper induces radioadaptive response as well as the harder radiation such as 260 kV X-ray filtered through 0.5 mm aluminum and 0.3 mm copper. Dose rate of priming irradiation also seemed to influence the induction of radioresistance. Priming irradiation with 0.50 Gy at 0.50 Gy/min and 0.25 Gy/min induced adaptive response, while same 0.50 Gy given at 0.063 Gy/min didn't. To make the matter complicated, when mice were pre-irradiated with 0.50 Gy at 0.013 Gy/min in the irradiation cell which was 1.2 x 1.2 x 1.4 times larger than the usual one, adaptive response was induced again. These results suggested that mice felt more uncomfortable when they were packing in the irradiation cell with little free space even for several minutes than when they were placed in the cell with much free space for about 40 minutes, and such a stress might give the mice some resistance to the subsequent sublethal irradiation. (author)

Studies on adaptive response of lymphocyte transformation induced by low-dose irradiation

International Nuclear Information System (INIS)

Du Zeji; Su Liaoyuan; Tian Hailin; Zou Huawei

1995-10-01

Human peripheral blood lymphocytes stimulated by mitogen in vitro for 24 h were exposed to low-dose γ-ray irradiation (0.5∼4.0 cGy, adaptive dose). They showed an adaptive response to the inhibition of 3 H-TdR incorporation by subsequent higher acute doses of γ-ray (challenge dose). At the interval of 24 h between adaptive dose and challenge dose, the strongest adaptive response induced by low-dose irradiation was found. It is also found that the response induced by 1.0 cGy of adaptive dose was more obvious than that by other doses and that 3.0 Gy of challenge dose produced the strongest adaptive response. As the challenge doses increased, the adaptive response reduced. (2 figs., 2 tabs.)

Incorporating adaptive responses into future projections of coral bleaching.

Science.gov (United States)

Logan, Cheryl A; Dunne, John P; Eakin, C Mark; Donner, Simon D

2014-01-01

Climate warming threatens to increase mass coral bleaching events, and several studies have projected the demise of tropical coral reefs this century. However, recent evidence indicates corals may be able to respond to thermal stress though adaptive processes (e.g., genetic adaptation, acclimatization, and symbiont shuffling). How these mechanisms might influence warming-induced bleaching remains largely unknown. This study compared how different adaptive processes could affect coral bleaching projections. We used the latest bias-corrected global sea surface temperature (SST) output from the NOAA/GFDL Earth System Model 2 (ESM2M) for the preindustrial period through 2100 to project coral bleaching trajectories. Initial results showed that, in the absence of adaptive processes, application of a preindustrial climatology to the NOAA Coral Reef Watch bleaching prediction method overpredicts the present-day bleaching frequency. This suggests that corals may have already responded adaptively to some warming over the industrial period. We then modified the prediction method so that the bleaching threshold either permanently increased in response to thermal history (e.g., simulating directional genetic selection) or temporarily increased for 2-10 years in response to a bleaching event (e.g., simulating symbiont shuffling). A bleaching threshold that changes relative to the preceding 60 years of thermal history reduced the frequency of mass bleaching events by 20-80% compared with the 'no adaptive response' prediction model by 2100, depending on the emissions scenario. When both types of adaptive responses were applied, up to 14% more reef cells avoided high-frequency bleaching by 2100. However, temporary increases in bleaching thresholds alone only delayed the occurrence of high-frequency bleaching by ca. 10 years in all but the lowest emissions scenario. Future research should test the rate and limit of different adaptive responses for coral species across latitudes and

Biobehavioral Insights into Adaptive Behavior in Complex and Dynamic Operational Settings: Lessons learned from the Soldier Performance and Effective, Adaptable Response Task

Directory of Open Access Journals (Sweden)

Amy J. Haufler

2018-02-01

Full Text Available The purpose of this study was to explore the biobehavioral correlates of adaptive behavior in the context of a standardized laboratory-based mission-relevant challenge [the Soldier Performance and Effective, Adaptable Response (SPEAR task]. Participants were 26 healthy male volunteers (M = 34.85 years, SD = 4.12 with active military duty and leadership experience within the last 5 years (i.e., multiple leadership positions, operational deployments in combat, interactions with civilians and partner nation forces on the battlefield, experience making decisions under fire. The SPEAR task simultaneously engages perception, cognition, and action aspects of human performance demands similar to those encountered in the operational setting. Participants must engage with military-relevant text, visual, and auditory stimuli, interpret new information, and retain the commander’s intent in working memory to create a new plan of action for mission success. Time-domain measures of heart period and respiratory sinus arrhythmia (RSA were quantified, and saliva was sampled [later assayed for cortisol and alpha-amylase (sAA] before-, during-, and post-SPEAR. Results revealed a predictable pattern of withdraw and recovery of the cardiac vagal tone during repeated presentation of battlefield challenges. Recovery of vagal inhibition following executive function challenge was strongly linked to better task-related performance. Rate of RSA recovery was also associated with better recall of the commander’s intent. Decreasing magnitude in the skin conductance response prior to the task was positively associated with better overall task-related performance. Lower levels of RSA were observed in participants who reported higher rates of combat deployments, and reduced RSA flexibility was associated with higher rates of casualty exposure. Greater RSA flexibility during SPEAR was associated with greater self-reported resilience. There was no consistent

Adaptive response of yeast cultures (Saccharomyces Cerevisiae) exposed to low dose of gamma radiation

International Nuclear Information System (INIS)

Kulcsar, Agnes; Savu, D.; Petcu, I.; Gherasim, Raluca

2003-01-01

The present study was planned as follows: (i) setting up of standard experimental conditions for investigation of radio-induced adaptive response in lower Eucaryotes; (ii) developing of procedures for synchronizing Saccharomyces cerevisiae X 310 D cell cultures and cell cycle stages monitoring; (iii) investigation of gamma (Co-60) and UV irradiation effects on the viability of synchronized and non-synchronized cell cultures of Saccharomyces cerevisiae; the effects were correlated with the cell density and cell cycle stage; (iv) study of the adaptive response induced by irradiation and setting up of the experimental conditions for which this response is optimized. The irradiations were performed by using a Co-60 with doses of 10 2 - 10 4 Gy and dose rates ranging from 2.2 x 10 2 Gy/h to 8.7 x 10 3 Gy/h. The study of radioinduced adaptive response was performed by applying a pre-irradiation treatment of 100-500 Gy, followed by challenge doses of 2-4 kGy delivered at different time intervals, ranging from 1 h to 4 h. The survival rate of synchronized and non-synchronized cultures as a function of exposure dose shows an exponential decay shape. No difference in viability of the cells occurred between synchronized and non-synchronized cultures. The pre-irradiation of cells with 100 and 200 Gy were most efficient to induce an adaptive response for the yeast cells. In this stage of work we proved the occurrence of the adaptive response in the case of synchronized yeast cultures exposed to gamma radiation. The results will be used in the future to investigate the dependence of this response on the cell cycle and the possibility to induce such a response by a low level electromagnetic field. (authors)

An Immune-inspired Adaptive Automated Intrusion Response System Model

Directory of Open Access Journals (Sweden)

Ling-xi Peng

2012-09-01

Full Text Available An immune-inspired adaptive automated intrusion response system model, named as , is proposed. The descriptions of self, non-self, immunocyte, memory detector, mature detector and immature detector of the network transactions, and the realtime network danger evaluation equations are given. Then, the automated response polices are adaptively performed or adjusted according to the realtime network danger. Thus, not only accurately evaluates the network attacks, but also greatly reduces the response times and response costs.

Bayesian selective response-adaptive design using the historical control.

Science.gov (United States)

Kim, Mi-Ok; Harun, Nusrat; Liu, Chunyan; Khoury, Jane C; Broderick, Joseph P

2018-06-13

High quality historical control data, if incorporated, may reduce sample size, trial cost, and duration. A too optimistic use of the data, however, may result in bias under prior-data conflict. Motivated by well-publicized two-arm comparative trials in stroke, we propose a Bayesian design that both adaptively incorporates historical control data and selectively adapt the treatment allocation ratios within an ongoing trial responsively to the relative treatment effects. The proposed design differs from existing designs that borrow from historical controls. As opposed to reducing the number of subjects assigned to the control arm blindly, this design does so adaptively to the relative treatment effects only if evaluation of cumulated current trial data combined with the historical control suggests the superiority of the intervention arm. We used the effective historical sample size approach to quantify borrowed information on the control arm and modified the treatment allocation rules of the doubly adaptive biased coin design to incorporate the quantity. The modified allocation rules were then implemented under the Bayesian framework with commensurate priors addressing prior-data conflict. Trials were also more frequently concluded earlier in line with the underlying truth, reducing trial cost, and duration and yielded parameter estimates with smaller standard errors. © 2018 The Authors. Statistics in Medicine Published by John Wiley & Sons, Ltd.

Adaptation response surfaces for managing wheat under perturbed climate and CO2 in a Mediterranean environment

DEFF Research Database (Denmark)

Ruiz-Ramos, M.; Ferrise, Roberto; Rodríguez, A

2018-01-01

type were analysed by constructing response surfaces, which we termed, in accordance with their specific purpose, adaptation response surfaces (ARSs). These were created to assess the effect of adaptations through a range of plausible P, T and [CO2] perturbations. The results indicated that impacts....... However, a single sI was sufficient to develop a high adaptation potential, including options mainly based on spring wheat, current cycle duration and early sowing date. Depending on local environment (e.g. soil type), many of these adaptations can maintain current yield levels under moderate changes in T...

Adaptive Response to ionizing Radiation Induced by Low Doses of Gamma Rays in Human Lymphoblastoid Cell Lines

International Nuclear Information System (INIS)

Seong, Jin Sil; Suh, Chang Ok; Kim, Gwi Eon

1994-01-01

When cells are exposed to low doses of a mutagenic or clastogenic agents, they often become less sensitive to the effects of a higher does administered subsequently. Such adaptive responses were first described in Escherichia coli and mammalian cells to low doses of an alkylating agent. Since most of the studies have been carried out with human lymphocytes, it is urgently necessary to study this effect in different cellular systems. Its relation with inherent cellular radiosensitivity and underlying mechanism also remain to be answered. In this study, adaptive response by 1 cGy of gamma rays was investigated in three human lymphoblastoid cell lines which were derived from ataxia telangiectasia homozygote, ataxia telangiectasia heterozygote, and normal individual. Experiments were carried out by delivering 1 cGy followed by 50 cGy of gamma radiation and chromatid breaks were scored as an endpoint. The results indicate that prior exposure to 1 cGy of gamma rays reduces the number of chromatid breaks induced by subsequent higher does (50 cGy). The expression of this adaptive response was similar among three cell lines despite of their different radiosensitivity. When 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, was added after 50 cGy, adaptive responses were abolished in all the tested cell lines. Therefore it is suggested that the adaptive response can be observed in human lymphoblastoid cell lines. Which was first documented through this study. The expression of adaptive response was similar among the cell lines regardless of their radiosensitivity. The elimination of the adaptive response by 3-aminobenzamide is consistent with the proposal that this adaptive response is the result of the induction of a certain chromosomal repair mechanism

Contextualizing Individual Competencies for Managing the Corporate Social Responsibility Adaptation Process

NARCIS (Netherlands)

Osagie, E.R.; Wesselink, R.; Blok, V.; Mulder, M.

2016-01-01

Companies committed to corporate social responsibility (CSR) should ensure that their managers possess the appropriate competencies to effectively manage the CSR adaptation process. The literature provides insights into the individual competencies these managers need but fails to prioritize them and

Adaptation or Resistance: a classification of responses to sea-level rise

Science.gov (United States)

Cooper, J. A.

2016-02-01

Societal responses to sea level rise and associated coastal change are apparently diverse in nature and motivation. Most are commonly referred to as 'adaptation'. Based on a review of current practice, however, it is argued that many of these responses do not involve adaptation, but are rather resisting change. There are several instances where formerly adaptive initiatives involving human adaptability are being replaced by initiatives that resist change. A classification is presented that recognises a continuum of responses ranging from adaptation to resistance, depending upon the willingness to change human activities to accommodate environmental change. In many cases climate change adaptation resources are being used for projects that are purely resistant and which foreclose future adaptation options. It is argued that a more concise definition of adaptation is needed if coastal management is to move beyond the current position of holding the shoreline, other tah n in a few showcase examples.

Optimal time interval for induction of immunologic adaptive response

International Nuclear Information System (INIS)

Ju Guizhi; Song Chunhua; Liu Shuzheng

1994-01-01

The optimal time interval between prior dose (D1) and challenge dose (D2) for the induction of immunologic adaptive response was investigated. Kunming mice were exposed to 75 mGy X-rays at a dose rate of 12.5 mGy/min. 3, 6, 12, 24 or 60 h after the prior irradiation the mice were challenged with a dose of 1.5 Gy at a dose rate of 0.33 Gy/min. 18h after D2, the mice were sacrificed for examination of immunological parameters. The results showed that with an interval of 6 h between D1 and D2, the adaptive response of the reaction of splenocytes to LPS was induced, and with an interval of 12 h the adaptive responses of spontaneous incorporation of 3 H-TdR into thymocytes and the reaction of splenocytes to Con A and LPS were induced with 75 mGy prior irradiation. The data suggested that the optimal time intervals between D1 and D2 for the induction of immunologic adaptive response were 6 h and 12 h with a D1 of 75 mGy and a D2 of 1.5 Gy. The mechanism of immunologic adaptation following low dose radiation is discussed

Molecular mechanism of radioadaptive response: A cross-adaptive response for enhanced repair of DNA damage in adapted cells

International Nuclear Information System (INIS)

Takaji Ikushima

1997-01-01

The radioadaptive response (RAR) has been attributed to the induction of a repair mechanism by low doses of ionizing radiation, but the molecular nature of the mechanism is not yet elucidated. We have characterized RAR in a series of experiments in cultured Chinese hamster V79 cells. A 4-h interval is required for the full expression of RAR, which decays with the progression of cell proliferation. Treatments with inhibitors of poly(ADP-ribose) polymerase, protein- or RNA synthesis, and protein kinase C suppress the RAR expression. The RAR cross-reacts on clastogenic lesions induced by other physical and chemical DNA-damaging agents. The presence of newly synthesised proteins has been detected during the expression period. Experiments performed using single-cell gel electrophoresis provided more direct evidence for a faster and enhaced DNA repair rate in adapted cells. Here, using single-cell gel electrophoresis, a cross-adaptive response has been demonstrated for enhanced repair of DNA damage induced by neocarzinostatin in radio-adapted cells. (author)

Dynamic adjustments of cognitive control: oscillatory correlates of the conflict adaptation effect.

Science.gov (United States)

Pastötter, Bernhard; Dreisbach, Gesine; Bäuml, Karl-Heinz T

2013-12-01

It is a prominent idea that cognitive control mediates conflict adaptation, in that response conflict in a previous trial triggers control adjustments that reduce conflict in a current trial. In the present EEG study, we investigated the dynamics of cognitive control in a response-priming task by examining the effects of previous trial conflict on intertrial and current trial oscillatory brain activities, both on the electrode and the source level. Behavioral results showed conflict adaptation effects for RTs and response accuracy. Physiological results showed sustained intertrial effects in left parietal theta power, originating in the left inferior parietal cortex, and midcentral beta power, originating in the left and right (pre)motor cortex. Moreover, physiological analysis revealed a current trial conflict adaptation effect in midfrontal theta power, originating in the ACC. Correlational analyses showed that intertrial effects predicted conflict-induced midfrontal theta power in currently incongruent trials. In addition, conflict adaptation effects in midfrontal theta power and RTs were positively related. Together, these findings point to a dynamic cognitive control system that, as a function of previous trial type, up- and down-regulates attention and preparatory motor activities in anticipation of the next trial.

Oxidized DNA induces an adaptive response in human fibroblasts

Energy Technology Data Exchange (ETDEWEB)

Kostyuk, Svetlana V., E-mail: svet.kostyuk@gmail.com [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Tabakov, Viacheslav J.; Chestkov, Valerij V.; Konkova, Marina S.; Glebova, Kristina V.; Baydakova, Galina V.; Ershova, Elizaveta S.; Izhevskaya, Vera L. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Baranova, Ancha, E-mail: abaranov@gmu.edu [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Center for the Study of Chronic Metabolic Diseases, School of System Biology, George Mason University, Fairfax, VA 22030 (United States); Veiko, Natalia N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

2013-07-15

Highlights: • We describe the effects of gDNAOX on human fibroblasts cultivated in serum withdrawal conditions. • gDNAOX evokes an adaptive response in human fibroblasts. • gDNAOX increases the survival rates in serum starving cell populations. • gDNAOX enhances the survival rates in cell populations irradiated at 1.2 Gy dose. • gDNAOX up-regulates NRF2 and inhibits NF-kappaB-signaling. - Abstract: Cell-free DNA (cfDNA) released from dying cells contains a substantial proportion of oxidized nucleotides, thus, forming cfDNA{sup OX}. The levels of cfDNA{sup OX} are increased in the serum of patients with chronic diseases. Oxidation of DNA turns it into a stress signal. The samples of genomic DNA (gDNA) oxidized by H{sub 2}O{sub 2}in vitro (gDNA{sup OX}) induce effects similar to that of DNA released from damaged cells. Here we describe the effects of gDNA{sup OX} on human fibroblasts cultivated in the stressful conditions of serum withdrawal. In these cells, gDNA{sup OX} evokes an adaptive response that leads to an increase in the rates of survival in serum starving cell populations as well as in populations irradiated at the dose of 1.2 Gy. These effects are not seen in control populations of fibroblasts treated with non-modified gDNA. In particular, the exposure to gDNA{sup OX} leads to a decrease in the expression of the proliferation marker Ki-67 and an increase in levels of PSNA, a decrease in the proportion of subG1- and G2/M cells, a decrease in proportion of cells with double strand breaks (DSBs). Both gDNA{sup OX} and gDNA suppress the expression of DNA sensors TLR9 and AIM2 and up-regulate nuclear factor-erythroid 2 p45-related factor 2 (NRF2), while only gDNA{sup OX} inhibits NF-κB signaling. gDNA{sup OX} is a model for oxidized cfDNA{sup OX} that is released from the dying tumor cells and being carried to the distant organs. The systemic effects of oxidized DNA have to be taken into account when treating tumors. In particular, the damaged DNA

Micro-evolutionary responses and adaptive costs of Caenorhabditis elegans populations exposed to environmental stress

International Nuclear Information System (INIS)

Dutilleul, M.

2013-01-01

The contemporary evolution of organisms is largely dependent on anthropogenic disturbances. In particular, pollution amplifies the intensity or the quantity of selection pressures on populations. However, these changes may have negative effects on the life, growth and reproduction of individuals, the demographics of the population, and its phenotypic and genetic characteristics over generations. Thus, micro-evolutionary changes are likely to occur in response to selection pressures. These phenomenon lead to collateral damages: adaptive costs. For example, a reduction of genetic diversity in a population entails a decrease in its potential to adapt to other stressors. Populations can be more susceptible to many environmental changes, especially with the increase of human activities. Hence in an ecological risk assessment, studying the mechanisms of action and immediate adverse effects of pollutants on organisms is no longer sufficient. It is also necessary to expand our knowledge on the evolution of populations in polluted environment. In this context, our study aims to determine the micro-evolutionary response of Caenorhabditis elegans populations exposed to environmental stressors, and to measure their costs of adaptation. Populations were experimentally exposed for 22 generations to a high concentration of uranium, sodium chloride or an alternation of both these pollutants. The analysis of phenotypic and genetic changes, observed through measures of life history traits, was accomplished using several quantitative genetics techniques. In particular, we confirmed the genetic differentiation between populations with an increase of resistance in populations exposed to different pollutions. The speed of evolutionary responses depended on the conditions of exposure and their effects on the expression of the genetic structure of traits (e.g. G matrix). Micro-evolutionary changes were linked to costs of adaptation, such as reduced fertility in stressful novel

Target Response Adaptation for Correlation Filter Tracking

KAUST Repository

Bibi, Adel Aamer

2016-09-16

Most correlation filter (CF) based trackers utilize the circulant structure of the training data to learn a linear filter that best regresses this data to a hand-crafted target response. These circularly shifted patches are only approximations to actual translations in the image, which become unreliable in many realistic tracking scenarios including fast motion, occlusion, etc. In these cases, the traditional use of a single centered Gaussian as the target response impedes tracker performance and can lead to unrecoverable drift. To circumvent this major drawback, we propose a generic framework that can adaptively change the target response from frame to frame, so that the tracker is less sensitive to the cases where circular shifts do not reliably approximate translations. To do that, we reformulate the underlying optimization to solve for both the filter and target response jointly, where the latter is regularized by measurements made using actual translations. This joint problem has a closed form solution and thus allows for multiple templates, kernels, and multi-dimensional features. Extensive experiments on the popular OTB100 benchmark show that our target adaptive framework can be combined with many CF trackers to realize significant overall performance improvement (ranging from 3 %-13.5% in precision and 3.2 %-13% in accuracy), especially in categories where this adaptation is necessary (e.g. fast motion, motion blur, etc.). © Springer International Publishing AG 2016.

Request for Information Response for the Flight Validation of Adaptive Control to Prevent Loss-of-Control Events. Overview of RFI Responses

Science.gov (United States)

Bosworth, John T.

2009-01-01

Adaptive control should be integrated with a baseline controller and only used when necessary (5 responses). Implementation as an emergency system. Immediately re-stabilize and return to controlled flight. Forced perturbation (excitation) for fine-tuning system a) Check margins; b) Develop requirements for amplitude of excitation. Adaptive system can improve performance by eating into margin constraints imposed on the non-adaptive system. Nonlinear effects due to multi-string voting.

The possible role of chromatin conformation changes in adaptive responses to ionizing radiation

International Nuclear Information System (INIS)

Ekhtiar, A.; Ammer, A.; Jbawi, A.; Othman, A.

2012-05-01

Organisms are affected by different DNA damaging agents naturally present in the environment or released as a result of human activity. Many defense mechanisms have evolved in organisms to minimize genotoxic damage. One of them is induced radioresistance or adaptive response. The adaptive response could be considered as a nonspecific phenomenon in which exposure to minimal stress could result in increased resistance to higher levels of the same or to other types of stress some hours later. A better understanding of the molecular mechanism underlying the adaptive response may lead to an improvement of cancer treatment, risk assessment and risk management strategies, radiation protection. The aim of current study was to study the possible role of chromatin conformation changes induced by ionizing radiation on the adaptive responses in human lymphocyte. For this aim the chromatin conformation have been studied in human lymphocytes from three non-smoking and three smoking healthy volunteers prior, and after espouser to gamma radiation (adaptive dose 0.1 Gy, challenge dose 1.5 Gy and adaptive + dose challenge). Chromosomal aberrations and micronucleus have been used as end point to study radio cytotoxicity and adaptive response. Our results indicated individual differences in radio adaptive response and the level of this response was dependent of chromatin de condensation induced by a adaptive small dose.The results showed that different dose of gamma rays induce a chromatin de condensation in human lymphocyte. The maximum chromatin relaxation were record when lymphocyte exposed to adaptive dose (0.1 Gy.). Results also showed that Adaptive dose have affected on the induction of challenge dose (1.5 Gy) of chromosome aberration and micronucleus . The comparison of results of chromatin de condensation induction as measured by flow cytometry and cytogenetic damages measured by chromosomal aberrations or micronucleus, was showed a proportionality of adaptive response with

Distinguishing Byproducts from Non-Adaptive Effects of Algorithmic Adaptations

Directory of Open Access Journals (Sweden)

Justin H. Park

2007-01-01

Full Text Available I evaluate the use of the byproduct concept in psychology, particularly the adaptation-byproduct distinction that is commonly invoked in discussions of psychological phenomena. This distinction can be problematic when investigating algorithmic mechanisms and their effects, because although all byproducts may be functionless concomitants of adaptations, not all incidental effects of algorithmic adaptations are byproducts (although they have sometimes been labeled as such. I call attention to Sperber's (1994 distinction between proper domains and actual domains of algorithmic mechanisms. Extending Sperber's distinction, I propose the terms adaptive effects and non-adaptive effects, which more accurately capture the phenomena of interest to psychologists and prevent fruitless adaptation-versus-byproduct debates.

Studies of adaptive response and mutation induction in MCF-10A cells following exposure to chronic or acute ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Manesh, Sara Shakeri; Sangsuwan, Traimate; Wojcik, Andrzej; Haghdoost, Siamak, E-mail: Siamak.haghdoost@su.se

2015-10-15

Highlights: • 50 mGy at 1.4 mGy/h induces adaptive response in MCF-10A at mutation level. • Low dose rate γ-radiation does not induce adaptive response at survival level. • Overall, a dose rate effect is absent at the level of mutation in MCF-10A cells. - Abstract: A phenomenon in which exposure to a low adapting dose of radiation makes cells more resistant to the effects of a subsequent high dose exposure is termed radio-adaptive response. Adaptive response could hypothetically reduce the risk of late adverse effects of chronic or acute radiation exposures in humans. Understanding the underlying mechanisms of such responses is of relevance for radiation protection as well as for the clinical applications of radiation in medicine. However, due to the variability of responses depending on the model system and radiation condition, there is a need to further study under what conditions adaptive response can be induced. In this study, we analyzed if there is a dose rate dependence for the adapting dose, assuming that the adapting dose induces DNA response/repair pathways that are dose rate dependent. MCF-10A cells were exposed to a 50 mGy adapting dose administered acutely (0.40 Gy/min) or chronically (1.4 mGy/h or 4.1 mGy/h) and then irradiated by high acute challenging doses. The endpoints of study include clonogenic cell survival and mutation frequency at X-linked hprt locus. In another series of experiment, cells were exposed to 100 mGy and 1 Gy at different dose rates (acutely and chronically) and then the mutation frequencies were studied. Adaptive response was absent at the level of clonogenic survival. The mutation frequencies were significantly decreased in the cells pre-exposed to 50 mGy at 1.4 mGy/h followed by 1 Gy acute exposure as challenging dose. Importantly, at single dose exposures (1 Gy or 100 mGy), no differences at the level of mutation were found comparing different dose rates.

The cellular adaptive response the role in life organisms

International Nuclear Information System (INIS)

Smith, H.

1998-01-01

Exposure of living cells to ionizing radiation may cause DNA damage that are generally harmful to the organism. This paper discuss the cellular adaptive response which may be seen when cells which have already been exposed to low concentration radiation doses are subsequently exposed to high concentration doses. It also discusses evidence of the adaptive response in laboratory animals and from limited epidemiological studies. (Author)

Effectiveness of Item Response Theory (IRT) Proficiency Estimation Methods under Adaptive Multistage Testing. Research Report. ETS RR-15-11

Science.gov (United States)

Kim, Sooyeon; Moses, Tim; Yoo, Hanwook Henry

2015-01-01

The purpose of this inquiry was to investigate the effectiveness of item response theory (IRT) proficiency estimators in terms of estimation bias and error under multistage testing (MST). We chose a 2-stage MST design in which 1 adaptation to the examinees' ability levels takes place. It includes 4 modules (1 at Stage 1, 3 at Stage 2) and 3 paths…

Adrenal hormones and the anorectic response and adaptation of rats to amino acid imbalance.

Science.gov (United States)

Hammer, V A; Gietzen, D W; Sworts, V D; Beverly, J L; Rogers, Q R

1990-12-01

The role of adrenal function in the anorectic response and adaptation of rats to a diet with an isoleucine (Ile) imbalance was investigated. In the first of four experiments, rats were fed a mildly Ile-imbalanced diet after treatment with metyrapone, and inhibitor of glucocorticoid synthesis. In two separate experiments, rats were presented with either a mildly or severely Ile-imbalanced diet (4.93 and 9.86% imbalanced amino acid mixture, respectively) after bilateral adrenalectomy. Finally, the effects of ICS 205-930, a serotonin-3 receptor antagonist, on the intake of mildly Ile-imbalanced diet were tested in adrenalectomized animals. In each experiment a 2 X 2 factorial design was used. Neither metyrapone nor adrenalectomy altered the initial depression in the intake of an imbalanced diet. The adaptation phase in the response of adrenalectomized rats fed a mildly Ile-imbalanced diet was not different from that of controls, but adrenalectomized rats fed severely Ile-imbalanced diets were unable to adapt. Adrenalectomy did not alter the anti-anoretic activity of ICS 205-930 in this model. These results suggest that adrenal hormones are not necessary for the initial anoretic response or adaptation of rats to an Ile-imbalanced diet, nor are they implicated in the anti-anorectic effect of serotonin-3 blockade.

Involvement of p27CIP/KIP in HSP25 or HSP70 Mediated Adaptive Response by Low Dose Radiation

International Nuclear Information System (INIS)

Seo, Hang Rhan; Lee, Yoon Jin; Lee, Su Jae; Bae, Sang woo; Lee, Yun Sil

2005-01-01

Adaptive responses that reduce the harmful effects of subsequent exposure to high-dose radiation have demonstrated in chromosome aberration, cell survival, sister chromatid exchanges, micronucleus induction, mutation and neoplastic transformation. The mechanisms and conditions for the adaptive response to radiation have not been clarified, although the continuous production of free radicals from radiation and other sources has stimulated cells to evolve a repair system for chromosome breaks. An alteration of the DNA molecule triggers the repair system, and frequent activation may increase the general repair capacity, irrespective of the cause of the damage. Besides, cell cycle regulation systems, antioxidant defense systems, molecular chaperone or stress-response systems. Our previous data showed that when cells were preirradiated with 1cGy, they showed the adaptive response. A reduction of apoptosis by low-dose preirradiation is another potential mechanism for this effect. We previously demonstrated that mouse RIF cells, which did not induce HSP25 and HSP70 did not exhibit a adaptive response after 1cGy preirradiation. whereas the thermoresistant TR cells, which expressed inducible HSP25 and HSP70 showed a response. Moreover, when HSP70 and HSP25 were transfected to RIF cells, the cells acquired adaptive response. In this study, to elucidate the mechanisms in induction of adaptiveresponse, we compared cell cycle distribution by low dose radiation after HSP25 or HSP70 transfected cells and p27CIP/KIP is responsible for the different induction of adaptive response

Molecular mechanisms involved in adaptive responses to radiation, UV light, and heat

International Nuclear Information System (INIS)

Takahashi, Akihisa; Ohnishi, Takeo

2009-01-01

Viable organisms recognize and respond to environmental changes or stresses. When these environmental changes and their responses by organisms are extreme, they can limit viability. However, organisms can adapt to these different stresses by utilizing different possible responses via signal transduction pathways when the stress is not lethal. In particular, prior mild stresses can provide some aid to prepare organisms for subsequent more severe stresses. These adjustments or adaptations for future stresses have been called adaptive responses. These responses are present in bacteria, plants and animals. The following review covers recent research which can help describe or postulate possible mechanisms which may be active in producing adaptive responses to radiation, ultraviolet light, and heat. (author)

Adaptive Responses to Thermal Stress in Mammals

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Yasser Lenis Sanin

2015-12-01

Full Text Available The environment animals have to cope with is a combination of natural factors such as temperature. Extreme changes in these factors can alter homeostasis, which can lead to thermal stress. This stress can be due to either high temperatures or low temperatures. Energy transference for thermoregulation in homoeothermic animals occurs through several mechanisms: conduction, convection, radiation and evaporation. When animals are subjected to thermal stress, physiological mechanisms are activated which may include endocrine, neuroendocrine and behavioral responses. Activation of the neuroendocrine system affects the secretion of hormones and neurotransmitters which act collectively as response mechanisms that allow them to adapt to stress. Mechanisms which have developed through evolution to allow animals to adapt to high environmental temperatures and to achieve thermo tolerance include physiological and physical changes in order to reduce food intake and metabolic heat production, to increase surface area of skin to dissipate heat, to increase blood flow to take heat from the body core to the skin and extremities to dissipate the heat, to increase numbers and activity of sweat glands, panting, water intake and color adaptation of integument system to reflect heat. Chronic exposure to thermal stress can cause disease, reduce growth, decrease productive and reproductive performance and, in extreme cases, lead to death. This paper aims to briefly explain the physical and physiological responses of mammals to thermal stress, like a tool for biological environment adaptation, emphasizing knowledge gaps and offering some recommendations to stress control for the animal production system.

Plant Cell Adaptive Responses to Microgravity

Science.gov (United States)

Kordyum, Elizabeth; Kozeko, Liudmyla; Talalaev, Alexandr

simulated microgravity and temperature elevation have different effects on the small HSP genes belonging to subfamilies with different subcellular localization: cytosol/nucleus - PsHSP17.1-CII and PsHSP18.1-CI, cloroplasts - PsHSP26.2-Cl, endoplasmatic reticulum - PsHSP22.7-ER and mitochondria - PsHSP22.9-M: unlike high temperature, clinorotation does not cause denaturation of cell proteins, that confirms the sHSP chaperone function. Dynamics of investigated gene expression in pea seedlings growing 5 days after seed germination under clinorotation was similar to that in the stationary control. Similar patterns in dynamics of sHSP gene expression in the stationary control and under clinorotation may be one of mechanisms providing plant adaptation to simulated microgravity. It is pointed that plant cell responses in microgravity and under clinorotation vary according to growth phase, physiological state, and taxonomic position of the object. At the same time, the responses have, to some degree, a similar character reflecting the changes in cell organelle functional load. Thus, next certain changes in the structure and function of plant cells may be considered as adaptive: 1) an increase in the unsaturated fatty acid content in the plasmalemma, 2) rearrangements of organelle ultrastructure and an increase in their functional load, 3) an increase in cortical F-actin under destabilization of tubulin microtubules, 4) the level of gene expression and synthesis of heat shock proteins, 5) alterations of the enzyme and antioxidant system activity. The dynamics of these patterns demonstrated that the adaptation occurs on the principle of self-regulating systems in the limits of physiological norm reaction. The very importance of changed expression of genes involved in different cellular processes, especially HSP genes, in cell adaptation to altered gravity is discussed.

Bioanalytical evidence that chemicals in tattoo ink can induce adaptive stress responses.

Science.gov (United States)

Neale, Peta A; Stalter, Daniel; Tang, Janet Y M; Escher, Beate I

2015-10-15

Tattooing is becoming increasingly popular, particularly amongst young people. However, tattoo inks contain a complex mixture of chemical impurities that may pose a long-term risk for human health. As a first step towards the risk assessment of these complex mixtures we propose to assess the toxicological hazard potential of tattoo ink chemicals with cell-based bioassays. Targeted modes of toxic action and cellular endpoints included cytotoxicity, genotoxicity and adaptive stress response pathways. The studied tattoo inks, which were extracted with hexane as a proxy for the bioavailable fraction, caused effects in all bioassays, with the red and yellow tattoo inks having the greatest response, particularly inducing genotoxicity and oxidative stress response endpoints. Chemical analysis revealed the presence of polycyclic aromatic hydrocarbons in the tested black tattoo ink at concentrations twice the recommended level. The detected polycyclic aromatic hydrocarbons only explained 0.06% of the oxidative stress response of the black tattoo ink, thus the majority of the effect was caused by unidentified components. The study indicates that currently available tattoo inks contain components that induce adaptive stress response pathways, but to evaluate the risk to human health further work is required to understand the toxicokinetics of tattoo ink chemicals in the body. Copyright © 2015 Elsevier B.V. All rights reserved.

How Language Supports Adaptive Teaching through a Responsive Learning Culture

Science.gov (United States)

Johnston, Peter; Dozier, Cheryl; Smit, Julie

2016-01-01

For students to learn optimally, teachers must design classrooms that are responsive to the full range of student development. The teacher must be adaptive, but so must each student and the learning culture itself. In other words, adaptive teaching means constructing a responsive learning culture that accommodates and even capitalizes on diversity…

Higher Plants in Space: Microgravity Perception, Response, and Adaptation

Science.gov (United States)

Zheng, Hui Qiong; Han, Fei; Le, Jie

2015-11-01

Microgravity is a major abiotic stress in space. Its effects on plants may depend on the duration of exposure. We focused on two different phases of microgravity responses in space. When higher plants are exposed to short-term (seconds to hours) microgravity, such as on board parabolic flights and sounding rockets, their cells usually exhibit abiotic stress responses. For example, Ca 2+-, lipid-, and pH-signaling are rapidly enhanced, then the production of reactive oxygen species and other radicals increase dramatically along with changes in metabolism and auxin signaling. Under long-term (days to months) microgravity exposure, plants acclimatize to the stress by changing their metabolism and oxidative response and by enhancing other tropic responses. We conclude by suggesting that a systematic analysis of regulatory networks at the molecular level of higher plants is needed to understand the molecular signals in the distinct phases of the microgravity response and adaptation.

Towards Trustworthy Adaptive Case Management with Dynamic Condition Response Graphs

DEFF Research Database (Denmark)

Mukkamala, Raghava Rao; Hildebrandt, Thomas; Slaats, Tijs

2013-01-01

We describe how the declarative Dynamic Condition Response (DCR) Graphs process model can be used for trustworthy adaptive case management by leveraging the flexible execution, dynamic composition and adaptation supported by DCR Graphs. The dynamically composed and adapted graphs are verified for...

The Pupillary Orienting Response Predicts Adaptive Behavioral Adjustment after Errors.

Directory of Open Access Journals (Sweden)

Peter R Murphy

Full Text Available Reaction time (RT is commonly observed to slow down after an error. This post-error slowing (PES has been thought to arise from the strategic adoption of a more cautious response mode following deployment of cognitive control. Recently, an alternative account has suggested that PES results from interference due to an error-evoked orienting response. We investigated whether error-related orienting may in fact be a pre-cursor to adaptive post-error behavioral adjustment when the orienting response resolves before subsequent trial onset. We measured pupil dilation, a prototypical measure of autonomic orienting, during performance of a choice RT task with long inter-stimulus intervals, and found that the trial-by-trial magnitude of the error-evoked pupil response positively predicted both PES magnitude and the likelihood that the following response would be correct. These combined findings suggest that the magnitude of the error-related orienting response predicts an adaptive change of response strategy following errors, and thereby promote a reconciliation of the orienting and adaptive control accounts of PES.

Adaptation to Temporally Fluctuating Environments by the Evolution of Maternal Effects.

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Snigdhadip Dey

2016-02-01

Full Text Available All organisms live in temporally fluctuating environments. Theory predicts that the evolution of deterministic maternal effects (i.e., anticipatory maternal effects or transgenerational phenotypic plasticity underlies adaptation to environments that fluctuate in a predictably alternating fashion over maternal-offspring generations. In contrast, randomizing maternal effects (i.e., diversifying and conservative bet-hedging, are expected to evolve in response to unpredictably fluctuating environments. Although maternal effects are common, evidence for their adaptive significance is equivocal since they can easily evolve as a correlated response to maternal selection and may or may not increase the future fitness of offspring. Using the hermaphroditic nematode Caenorhabditis elegans, we here show that the experimental evolution of maternal glycogen provisioning underlies adaptation to a fluctuating normoxia-anoxia hatching environment by increasing embryo survival under anoxia. In strictly alternating environments, we found that hermaphrodites evolved the ability to increase embryo glycogen provisioning when they experienced normoxia and to decrease embryo glycogen provisioning when they experienced anoxia. At odds with existing theory, however, populations facing irregularly fluctuating normoxia-anoxia hatching environments failed to evolve randomizing maternal effects. Instead, adaptation in these populations may have occurred through the evolution of fitness effects that percolate over multiple generations, as they maintained considerably high expected growth rates during experimental evolution despite evolving reduced fecundity and reduced embryo survival under one or two generations of anoxia. We develop theoretical models that explain why adaptation to a wide range of patterns of environmental fluctuations hinges on the existence of deterministic maternal effects, and that such deterministic maternal effects are more likely to contribute to

Experimental studies on possible regulatory role of nitric oxide on the differential effects of chronic predictable and unpredictable stress on adaptive immune responses.

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Thakur, Tarun; Gulati, Kavita; Rai, Nishant; Ray, Arunabha

2017-09-01

The present study was designed to investigate the effects of chronic predictable stress (CPS) and chronic unpredictable stress (CUS) on immunological responses in KLH-sensitized rats and involvement of NOergic signaling pathways mediating such responses. Male Wistar rats (200-250g) were exposed to either CPS or CUS for 14days and IgG antibody levels and delayed type hypersensitivity (DTH) response was determined to assess changes in adaptive immunity. To evaluate the role of nitric oxide during such immunomodulation, biochemical estimation of stable metabolite of nitric oxide (NOx) and 3-nitrotyrosine (3-NT, a marker of peroxynitrite formation) were done in both blood and brain. Chronic stress exposure resulted in suppression of IgG and DTH response and elevated NOx and 3-NT levels, with a difference in magnitude of response in CPS vs CUS. Pretreatment with aminoguanidine (iNOS inhibitor) caused further reduction of adaptive immune responses and attenuated the increased NOx and 3-NT levels in CPS or CUS exposed rats. On the other hand 7-NI (nNOS inhibitor) did not significantly affect these estimated parameters. The results suggest involvement of iNOS and lesser/no role of nNOS during modulation of adaptive immunity to stress. Thus, the result showed that predictability of stressors results in differential degree of modulation of immune responses and complex NO-mediated signaling mechanisms may be involved during responses. Copyright © 2017. Published by Elsevier B.V.

Study on cellular survival adaptive response induced by low dose irradiation of 153Sm

International Nuclear Information System (INIS)

Zhu Shoupeng; Xiao Dong

1999-01-01

The present study engages in determining whether low dose irradiation of 153 Sm could cut down the responsiveness of cellular survival to subsequent high dose exposure of 153 Sm so as to make an inquiry into approach the protective action of adaptive response by second irradiation of 153 Sm. Experimental results indicate that for inductive low dose of radionuclide 153 Sm 3.7 kBq/ml irradiated beforehand to cells has obvious resistant effect in succession after high dose irradiation of 153 Sm 3.7 x 10 2 kBq/ml was observed. Cells exposed to low dose irradiation of 153 Sm become adapted and therefore the subsequent cellular survival rate induced by high dose of 153 Sm is sufficiently higher than high dose of 153 Sm merely. It is evident that cellular survival adaptive response could be induced by pure low dose irradiation of 153 Sm only

Climate Change and Infectious Disease Risk in Western Europe: A Survey of Dutch Expert Opinion on Adaptation Responses and Actors.

Science.gov (United States)

Akin, Su-Mia; Martens, Pim; Huynen, Maud M T E

2015-08-18

There is growing evidence of climate change affecting infectious disease risk in Western Europe. The call for effective adaptation to this challenge becomes increasingly stronger. This paper presents the results of a survey exploring Dutch expert perspectives on adaptation responses to climate change impacts on infectious disease risk in Western Europe. Additionally, the survey explores the expert sample's prioritization of mitigation and adaptation, and expert views on the willingness and capacity of relevant actors to respond to climate change. An integrated view on the causation of infectious disease risk is employed, including multiple (climatic and non-climatic) factors. The results show that the experts consider some adaptation responses as relatively more cost-effective, like fostering interagency and community partnerships, or beneficial to health, such as outbreak investigation and response. Expert opinions converge and diverge for different adaptation responses. Regarding the prioritization of mitigation and adaptation responses expert perspectives converge towards a 50/50 budgetary allocation. The experts consider the national government/health authority as the most capable actor to respond to climate change-induced infectious disease risk. Divergence and consensus among expert opinions can influence adaptation policy processes. Further research is necessary to uncover prevailing expert perspectives and their roots, and compare these.

Effects of the N-methyl-D-Aspartate receptor antagonist dextromethorphan on vibrotactile adaptation

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Folger Stephen E

2008-09-01

Full Text Available Abstract Background Previous reports have demonstrated that short durations of vibrotactile stimuli (less than or equal to 2 sec effectively and consistently modify both the perceptual response in humans as well as the neurophysiological response in somatosensory cortex. The change in cortical response with adaptation has been well established by a number of studies, and other reports have extended those findings in determining that both GABA- and NMDAR-mediated neurotransmission play a significant role in the dynamic response of somatosensory cortical neurons. In this study, we evaluated the impact that dextromethorphan (DXM, an NMDAR antagonist, had on two distinct vibrotactile adaptation tasks. Results All subjects, both those that ingested 60 mg DXM and those that ingested placebo, were evaluated for their amplitude discriminative capacity between two simultaneously delivered vibrotactile stimuli both with and without 3 conditions of pre-exposure to adapting stimulation. The results demonstrated that the perceptual metrics of subjects who ingested 60 mg DXM were significantly altered from that of controls when the amplitude discrimination task followed one of the conditions of adapting stimulation. Without the condition of pre-exposure to an adapting stimulus (or stimuli, there was little difference between the observations obtained from the subjects that ingested DXM and controls. Peak impact on subject response occurred at 60 min post-ingestion, whereas the scores of controls who ingested placebo were not impacted. Conclusion The results – that DXM blocks vibrotactile adaptation – is consistent with the suggestion that NMDAR-mediated neurotransmission plays a significant role in the perceptual adaptive response. This finding is also consistent with neurophysiological findings that report observations of the effects of NMDAR block on the SI cortical response to repetitive vibrotactile stimulation.

Possible stimuli for strength and power adaptation : acute metabolic responses.

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Crewther, Blair; Cronin, John; Keogh, Justin

2006-01-01

The metabolic response to resistance exercise, in particular lactic acid or lactate, has a marked influence upon the muscular environment, which may enhance the training stimulus (e.g. motor unit activation, hormones or muscle damage) and thereby contribute to strength and power adaptation. Hypertrophy schemes have resulted in greater lactate responses (%) than neuronal and dynamic power schemes, suggesting possible metabolic-mediated changes in muscle growth. Factors such as age, sex, training experience and nutrition may also influence the lactate responses to resistance exercise and thereafter, muscular adaptation. Although the importance of the mechanical and hormonal stimulus to strength and power adaptation is well recognised, the contribution of the metabolic stimulus is largely unknown. Relatively few studies for example, have examined metabolic change across neuronal and dynamic power schemes, and not withstanding the fact that those mechanisms underpinning muscular adaptation, in relation to the metabolic stimulus, remain highly speculative. Inconsistent findings and methodological limitations within research (e.g. programme design, sampling period, number of samples) make interpretation further difficult. We contend that strength and power research needs to investigate those metabolic mechanisms likely to contribute to weight-training adaptation. Further research is also needed to examine the metabolic responses to different loading schemes, as well as interactions across age, sex and training status, so our understanding of how to optimise strength and power development is improved.

Adaptation responses to increasing drought frequency

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Loch, A. J.; Adamson, D. C.; Schwabe, K.

2016-12-01

Using state contingent analysis we discuss how and why irrigators adapt to alternative water supply signals. This analysis approach helps to illustrate how and why producers currently use state-general and state-allocable inputs to adapt and respond to known and possible future climatic alternative natures. Focusing on the timing of water allocations, we explore inherent differences in the demand for water by two key irrigation sectors: annual and perennial producers which in Australia have allowed a significant degree of risk-minimisation during droughts. In the absence of land constraints, producers also had a capacity to respond to positive state outcomes and achieve super-normal profits. In the future, however, the probability of positive state outcomes is uncertain; production systems may need to adapt to minimise losses and/or achieve positive returns under altered water supply conditions that may arise as a consequence of more frequent drought states. As such, producers must assess whether altering current input/output choice sets in response to possible future climate states will enhance their long-run competitive advantage for both expected new normal and extreme water supply outcomes. Further, policy supporting agricultural sector climate change resilience must avoid poorly-designed strategies that increase producer vulnerability in the face of drought. Our analysis explores the reliability of alternative water property right bundles and how reduced allocations across time influence alternative responses by producers. We then extend our analysis to explore how management strategies could adapt to two possible future drier state types: i) where an average reduction in water supply is experienced; and ii) where the frequency of droughts increase. The combination of these findings are subsequently used to discuss the role water reform policy has to deal with current and future climate scenarios. We argue current policy strategies could drive producers to

Effect of vergence adaptation on convergence-accommodation: model simulations.

Science.gov (United States)

Sreenivasan, Vidhyapriya; Bobier, William R; Irving, Elizabeth L; Lakshminarayanan, Vasudevan

2009-10-01

Several theoretical control models depict the adaptation effects observed in the accommodation and vergence mechanisms of the human visual system. Two current quantitative models differ in their approach of defining adaptation and in identifying the effect of controller adaptation on their respective cross-links between the vergence and accommodative systems. Here, we compare the simulation results of these adaptation models with empirical data obtained from emmetropic adults when they performed sustained near task through + 2D lens addition. The results of our experimental study showed an initial increase in exophoria (a divergent open-loop vergence position) and convergence-accommodation (CA) when viewing through +2D lenses. Prolonged fixation through the near addition lenses initiated vergence adaptation, which reduced the lens-induced exophoria and resulted in a concurrent reduction of CA. Both models showed good agreement with empirical measures of vergence adaptation. However, only one model predicted the experimental time course of reduction in CA. The pattern of our empirical results seem to be best described by the adaptation model that indicates the total vergence response to be a sum of two controllers, phasic and tonic, with the output of phasic controller providing input to the cross-link interactions.

Cooperative adaptive responses in gene regulatory networks with many degrees of freedom.

Science.gov (United States)

Inoue, Masayo; Kaneko, Kunihiko

2013-04-01

Cells generally adapt to environmental changes by first exhibiting an immediate response and then gradually returning to their original state to achieve homeostasis. Although simple network motifs consisting of a few genes have been shown to exhibit such adaptive dynamics, they do not reflect the complexity of real cells, where the expression of a large number of genes activates or represses other genes, permitting adaptive behaviors. Here, we investigated the responses of gene regulatory networks containing many genes that have undergone numerical evolution to achieve high fitness due to the adaptive response of only a single target gene; this single target gene responds to changes in external inputs and later returns to basal levels. Despite setting a single target, most genes showed adaptive responses after evolution. Such adaptive dynamics were not due to common motifs within a few genes; even without such motifs, almost all genes showed adaptation, albeit sometimes partial adaptation, in the sense that expression levels did not always return to original levels. The genes split into two groups: genes in the first group exhibited an initial increase in expression and then returned to basal levels, while genes in the second group exhibited the opposite changes in expression. From this model, genes in the first group received positive input from other genes within the first group, but negative input from genes in the second group, and vice versa. Thus, the adaptation dynamics of genes from both groups were consolidated. This cooperative adaptive behavior was commonly observed if the number of genes involved was larger than the order of ten. These results have implications in the collective responses of gene expression networks in microarray measurements of yeast Saccharomyces cerevisiae and the significance to the biological homeostasis of systems with many components.

Interval for the expression of the adaptive response induced by gamma radiation in leucocytes of mouse In vivo

International Nuclear Information System (INIS)

Mendiola C, M.T.; Morales R, P.

2002-01-01

The interval between the adaptive gamma radiation dose (0.01 Gy) and challenge (1.0 Gy) capable to induce the maximum expression of the adaptive response in lymphocytes of mouse In vivo. The animals were exposed to the mentioned doses with different intervals among both (1, 1.5, 5 or 18 hr). By means of the unicellular electrophoresis in gel technique, four damage parameters were analysed. The results showed that from the 1 hr interval an adaptive response was produced since in the pretreated organisms with 0.01 Gy the cells present lesser damage than in those not adapted. The maximum response was induced with the intervals between 2.5 and 5 hr and even though it persisted until 18 hr, the effect was reducing. (Author)

Adaptive response of Peruvian Hake to overfishing

OpenAIRE

Mendo, C.W.; Carrasco, R.G.

2000-01-01

Compensatory mechanisms of the Peruvian hake population (Merluccius gayi peruanus) in response to heavy exploitation and changes in species interaction are discussed. Changes in the rate of cannibalism, diet composition, maximization of fecundity and behavioral adaptation are noted.

Neural Adaptation Effects in Conceptual Processing

Directory of Open Access Journals (Sweden)

Barbara F. M. Marino

2015-07-01

Full Text Available We investigated the conceptual processing of nouns referring to objects characterized by a highly typical color and orientation. We used a go/no-go task in which we asked participants to categorize each noun as referring or not to natural entities (e.g., animals after a selective adaptation of color-edge neurons in the posterior LV4 region of the visual cortex was induced by means of a McCollough effect procedure. This manipulation affected categorization: the green-vertical adaptation led to slower responses than the green-horizontal adaptation, regardless of the specific color and orientation of the to-be-categorized noun. This result suggests that the conceptual processing of natural entities may entail the activation of modality-specific neural channels with weights proportional to the reliability of the signals produced by these channels during actual perception. This finding is discussed with reference to the debate about the grounded cognition view.

Rapid adaptive responses to climate change in corals

KAUST Repository

Torda, Gergely; Donelson, Jennifer M.; Aranda, Manuel; Barshis, Daniel J.; Bay, Line; Berumen, Michael L.; Bourne, David G.; Cantin, Neal; Foret, Sylvain; Matz, Mikhail; Miller, David J.; Moya, Aurelie; Putnam, Hollie M.; Ravasi, Timothy; van Oppen, Madeleine J. H.; Thurber, Rebecca Vega; Vidal-Dupiol, Jeremie; Voolstra, Christian R.; Watson, Sue-Ann; Whitelaw, Emma; Willis, Bette L.; Munday, Philip L.

2017-01-01

Pivotal to projecting the fate of coral reefs is the capacity of reef-building corals to acclimatize and adapt to climate change. Transgenerational plasticity may enable some marine organisms to acclimatize over several generations and it has been hypothesized that epigenetic processes and microbial associations might facilitate adaptive responses. However, current evidence is equivocal and understanding of the underlying processes is limited. Here, we discuss prospects for observing transgenerational plasticity in corals and the mechanisms that could enable adaptive plasticity in the coral holobiont, including the potential role of epigenetics and coral-associated microbes. Well-designed and strictly controlled experiments are needed to distinguish transgenerational plasticity from other forms of plasticity, and to elucidate the underlying mechanisms and their relative importance compared with genetic adaptation.

Rapid adaptive responses to climate change in corals

KAUST Repository

Torda, Gergely

2017-09-01

Pivotal to projecting the fate of coral reefs is the capacity of reef-building corals to acclimatize and adapt to climate change. Transgenerational plasticity may enable some marine organisms to acclimatize over several generations and it has been hypothesized that epigenetic processes and microbial associations might facilitate adaptive responses. However, current evidence is equivocal and understanding of the underlying processes is limited. Here, we discuss prospects for observing transgenerational plasticity in corals and the mechanisms that could enable adaptive plasticity in the coral holobiont, including the potential role of epigenetics and coral-associated microbes. Well-designed and strictly controlled experiments are needed to distinguish transgenerational plasticity from other forms of plasticity, and to elucidate the underlying mechanisms and their relative importance compared with genetic adaptation.

Adaptive Response Surface Techniques in Reliability Estimation

DEFF Research Database (Denmark)

Enevoldsen, I.; Faber, M. H.; Sørensen, John Dalsgaard

1993-01-01

Problems in connection with estimation of the reliability of a component modelled by a limit state function including noise or first order discontinuitics are considered. A gradient free adaptive response surface algorithm is developed. The algorithm applies second order polynomial surfaces...

Central adaptation of pain perception in response to rehabilitation of musculoskeletal pain

DEFF Research Database (Denmark)

Andersen, Lars L; Andersen, Christoffer H; Sundstrup, Emil

2012-01-01

Understanding the mechanisms of long-standing musculoskeletal pain and adaptations in response to physical rehabilitation is important for developing optimal treatment strategies. The influence of central adaptations of pain perception in response to rehabilitation of musculoskeletal pain remains...

Radioadaptive response. Efficient repair of radiation-induced DNA damage in adapted cells

International Nuclear Information System (INIS)

Ikushima, Takaji; Aritomi, Hisako; Morisita, Jun

1996-01-01

To verify the hypothesis that the induction of a novel, efficient repair mechanism for chromosomal DNA breaks may be involved in the radioadaptive response, the repair kinetics of DNA damage has been studied in cultured Chinese hamster V79 cells with single-cell gel electrophoresis. The cells were adapted by priming exposure with 5 cGy of γ-rays and 4-h incubation at 37C. There were no indication of any difference in the initial yields of DNA double-strand breaks induced by challenging doses from non-adapted cells and from adapted cells. The rejoining of DNA double-strand breaks was monitored over 120 min after the adapted cells were challenged with 5 or 1.5 Gy, doses at the same level to those used in the cytogenetical adaptive response. The rate of DNA damage repair in adapted cells was higher than that in non-adapted cells, and the residual damage was less in adapted cells than in non-adapted cells. These results indicate that the radioadaptive response may result from the induction of a novel, efficient DNA repair mechanism which leads to less residual damage, but not from the induction of protective functions that reduce the initial DNA damage

Rapid feedback responses correlate with reach adaptation and properties of novel upper limb loads.

Science.gov (United States)

Cluff, Tyler; Scott, Stephen H

2013-10-02

A hallmark of voluntary motor control is the ability to adjust motor patterns for novel mechanical or visuomotor contexts. Recent work has also highlighted the importance of feedback for voluntary control, leading to the hypothesis that feedback responses should adapt when we learn new motor skills. We tested this prediction with a novel paradigm requiring that human subjects adapt to a viscous elbow load while reaching to three targets. Target 1 required combined shoulder and elbow motion, target 2 required only elbow motion, and target 3 (probe target) required shoulder but no elbow motion. This simple approach controlled muscle activity at the probe target before, during, and after the application of novel elbow loads. Our paradigm allowed us to perturb the elbow during reaching movements to the probe target and identify several key properties of adapted stretch responses. Adapted long-latency responses expressed (de-) adaptation similar to reaching errors observed when we introduced (removed) the elbow load. Moreover, reaching errors during learning correlated with changes in the long-latency response, showing subjects who adapted more to the elbow load displayed greater modulation of their stretch responses. These adapted responses were sensitive to the size and direction of the viscous training load. Our results highlight an important link between the adaptation of feedforward and feedback control and suggest a key part of motor adaptation is to adjust feedback responses to the requirements of novel motor skills.

Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change

Science.gov (United States)

Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

2014-01-01

Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data. PMID:24454550

Accounting for sequential trial effects in the flanker task: conflict adaptation or associative priming?

Science.gov (United States)

Nieuwenhuis, Sander; Stins, John F; Posthuma, Danielle; Polderman, Tinca J C; Boomsma, Dorret I; de Geus, Eco J

2006-09-01

The conflict-control loop theory proposes that the detection of conflict in information processing triggers an increase in cognitive control, resulting in improved performance on the subsequent trial. This theory seems consistent with the robust finding that conflict susceptibility is reduced following correct trials associated with high conflict: the conflict adaptation effect. However, despite providing favorable conditions for eliciting and detecting conflict-triggered performance adjustments, none of the five experiments reported here provide unequivocal evidence of such adjustments. Instead, the results corroborate and extend earlier findings by demonstrating that the conflict adaptation effect, at least in the flanker task, is only present for a specific subset of trial sequences that is characterized by a response repetition. This pattern of results provides strong evidence that the conflict adaptation effect reflects associative stimulus-response priming instead of conflict-driven adaptations in cognitive control.

Cytosolic phosphoenolpyruvate carboxykinase is a response gene involved in porcine adipocyte adaptation to heat stress.

Science.gov (United States)

Qu, Huan; Ajuwon, Kolapo M

2018-05-04

Heat stress (HS) leads to increased lipid storage and expression of cytosolic phosphoenolpyruvate carboxykinase (PCK1) in pig adipocytes. However, the importance of PCK1 activation and lipid storage in the adaptive response to HS is unknown. Therefore, in vitro experiments were conducted to investigate the effect of PCK1 inhibition with 3-mercaptopicolinic acid (3MPA) on lipid storage and adipocyte response during HS. In vitro culture of adipocytes under HS (41.0 °C) increased (P cultured adipocytes were less able to induce adaptive responses such as upregulation of HSP70 and triglycerides, and this exacerbated ER stress during HS. Thus, PCK1 may function to alleviate ER stress that occurs during HS.

Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments.

Science.gov (United States)

Cao, Mengyi; Goodrich-Blair, Heidi

2017-08-01

In mutually beneficial and pathogenic symbiotic associations, microbes must adapt to the host environment for optimal fitness. Both within an individual host and during transmission between hosts, microbes are exposed to temporal and spatial variation in environmental conditions. The phenomenon of phenotypic variation, in which different subpopulations of cells express distinctive and potentially adaptive characteristics, can contribute to microbial adaptation to a lifestyle that includes rapidly changing environments. The environments experienced by a symbiotic microbe during its life history can be erratic or predictable, and each can impact the evolution of adaptive responses. In particular, the predictability of a rhythmic or cyclical series of environments may promote the evolution of signal transduction cascades that allow preadaptive responses to environments that are likely to be encountered in the future, a phenomenon known as adaptive prediction. In this review, we summarize environmental variations known to occur in some well-studied models of symbiosis and how these may contribute to the evolution of microbial population heterogeneity and anticipatory behavior. We provide details about the symbiosis between Xenorhabdus bacteria and Steinernema nematodes as a model to investigate the concept of environmental adaptation and adaptive prediction in a microbial symbiosis. Copyright © 2017 American Society for Microbiology.

Responses of crayfish photoreceptor cells following intense light adaptation.

Science.gov (United States)

Cummins, D R; Goldsmith, T H

1986-01-01

After intense orange adapting exposures that convert 80% of the rhodopsin in the eye to metarhodopsin, rhabdoms become covered with accessory pigment and appear to lose some microvillar order. Only after a delay of hours or even days is the metarhodopsin replaced by rhodopsin (Cronin and Goldsmith 1984). After 24 h of dark adaptation, when there has been little recovery of visual pigment, the photoreceptor cells have normal resting potentials and input resistances, and the reversal potential of the light response is 10-15 mV (inside positive), unchanged from controls. The log V vs log I curve is shifted about 0.6 log units to the right on the energy axis, quantitatively consistent with the decrease in the probability of quantum catch expected from the lowered concentration of rhodopsin in the rhabdoms. Furthermore, at 24 h the photoreceptors exhibit a broader spectral sensitivity than controls, which is also expected from accumulations of metarhodopsin in the rhabdoms. In three other respects, however, the transduction process appears to be light adapted: The voltage responses are more phasic than those of control photoreceptors. The relatively larger effect (compared to controls) of low extracellular Ca++ (1 mmol/l EGTA) in potentiating the photoresponses suggests that the photoreceptors may have elevated levels of free cytoplasmic Ca++. The saturating depolarization is only about 30% as large as the maximal receptor potentials of contralateral, dark controls, and by that measure the log V-log I curve is shifted downward by 0.54 log units.(ABSTRACT TRUNCATED AT 250 WORDS)

Immune and stress responses in oysters with insights on adaptation.

Science.gov (United States)

Guo, Ximing; He, Yan; Zhang, Linlin; Lelong, Christophe; Jouaux, Aude

2015-09-01

Oysters are representative bivalve molluscs that are widely distributed in world oceans. As successful colonizers of estuaries and intertidal zones, oysters are remarkably resilient against harsh environmental conditions including wide fluctuations in temperature and salinity as well as prolonged air exposure. Oysters have no adaptive immunity but can thrive in microbe-rich estuaries as filter-feeders. These unique adaptations make oysters interesting models to study the evolution of host-defense systems. Recent advances in genomic studies including sequencing of the oyster genome have provided insights into oyster's immune and stress responses underlying their amazing resilience. Studies show that the oyster genomes are highly polymorphic and complex, which may be key to their resilience. The oyster genome has a large gene repertoire that is enriched for immune and stress response genes. Thousands of genes are involved in oyster's immune and stress responses, through complex interactions, with many gene families expanded showing high sequence, structural and functional diversity. The high diversity of immune receptors and effectors may provide oysters with enhanced specificity in immune recognition and response to cope with diverse pathogens in the absence of adaptive immunity. Some members of expanded immune gene families have diverged to function at different temperatures and salinities or assumed new roles in abiotic stress response. Most canonical innate immunity pathways are conserved in oysters and supported by a large number of diverse and often novel genes. The great diversity in immune and stress response genes exhibited by expanded gene families as well as high sequence and structural polymorphisms may be central to oyster's adaptation to highly stressful and widely changing environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Responsible Climate Change Adaptation : Exploring, analysing and evaluating public and private responsibilities for urban adaptation to climate change

NARCIS (Netherlands)

Mees, Heleen

2014-01-01

Cities are vulnerable to climate change. To deal with climate change, city governments and private actors such as businesses and citizens need to adapt to its effects, such as sea level rise, storm surges, intense rainfall and heatwaves. However, adaptation planning and action is often hampered when

Adaptability Responding Effectively to Change

CERN Document Server

(CCL), Center for Creative Leadership; Calarco, Allan

2011-01-01

In today's business world, the complexity and pace of change can be daunting. Adaptability has become recognized as a necessary skill for leaders to develop to be effective in this environment. Even so, leaders rarely know what they can do to become more adaptable and foster adaptability in others. This guidebook contributes to a greater understanding of adaptability and the cognitive, emotional, and dispositional flexibility it requires. Leaders will learn how to develop their adaptability and to become more effective for themselves, the people they lead, and their organizations.

Gender differences in farmers' responses to climate change adaptation in Yongqiao District, China.

Science.gov (United States)

Jin, Jianjun; Wang, Xiaomin; Gao, Yiwei

2015-12-15

This study examines the gender differences in farmers' responses to climate change adaption in Yongqiao District, China. A random sampling technique was used to select 220 household heads, while descriptive statistics and binary logit models were used to analyze the data obtained from the households. We determine that male and female respondents are not significantly different in their knowledge and perceptions of climate change, but there is a gender difference in adopting climate change adaptation measures. Male-headed households are more likely to adopt new technology for water conservation and to increase investment in irrigation infrastructure. The research also indicates that the adaptation decisions of male and female heads are influenced by different sets of factors. The findings of this research help to elucidate the determinants of climate change adaptation decisions for male and female-headed households and the strategic interventions necessary for effective adaptation. Copyright © 2015 Elsevier B.V. All rights reserved.

Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework

International Nuclear Information System (INIS)

Calabrese, Edward J.; Bachmann, Kenneth A.; Bailer, A. John; Bolger, P. Michael; Borak, Jonathan; Cai, Lu; Cedergreen, Nina; Cherian, M. George; Chiueh, Chuang C.; Clarkson, Thomas W.; Cook, Ralph R.; Diamond, David M.; Doolittle, David J.; Dorato, Michael A.; Duke, Stephen O.; Feinendegen, Ludwig; Gardner, Donald E.; Hart, Ronald W.; Hastings, Kenneth L.; Hayes, A. Wallace; Hoffmann, George R.; Ives, John A.; Jaworowski, Zbigniew; Johnson, Thomas E.; Jonas, Wayne B.; Kaminski, Norbert E.; Keller, John G.; Klaunig, James E.; Knudsen, Thomas B.; Kozumbo, Walter J.; Lettieri, Teresa; Liu, Shu-Zheng; Maisseu, Andre; Maynard, Kenneth I.; Masoro, Edward J.; McClellan, Roger O.; Mehendale, Harihara M.; Mothersill, Carmel; Newlin, David B.; Nigg, Herbert N.; Oehme, Frederick W.; Phalen, Robert F.; Philbert, Martin A.; Rattan, Suresh I.S.; Riviere, Jim E.; Rodricks, Joseph; Sapolsky, Robert M.; Scott, Bobby R.; Seymour, Colin; Sinclair, David A.; Smith-Sonneborn, Joan; Snow, Elizabeth T.; Spear, Linda; Stevenson, Donald E.; Thomas, Yolene; Tubiana, Maurice; Williams, Gary M.; Mattson, Mark P.

2007-01-01

Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stress. Due to a lack of frequent interaction among scientists in these many areas, there has emerged a broad range of terms that describe such dose-response relationships. This situation has become problematic because the different terms describe a family of similar biological responses (e.g., adaptive response, preconditioning, hormesis), adversely affecting interdisciplinary communication, and possibly even obscuring generalizable features and central biological concepts. With support from scientists in a broad range of disciplines, this article offers a set of recommendations we believe can achieve greater conceptual harmony in dose-response terminology, as well as better understanding and communication across the broad spectrum of biological disciplines

Effect of walking stress on growth, physiological adaptability and endocrine responses in Malpura ewes in a semi-arid tropical environment

Science.gov (United States)

Sejian, Veerasamy; Maurya, Vijai P.; Naqvi, Syed M. K.

2012-03-01

Sheep in hot semi-arid environments are mostly reared using extensive systems. In addition to thermal stress and feed scarcity, the animals need to walk long distances for grazing in this ecological zone. A study was conducted to assess the effect of long-distance walking on adaptive capability in terms of physiological, biochemical and endocrine responses in Malpura ewes. Fourteen adult Malpura non-pregnant ewes weighing between 33 and 35 kg were used in the study. The ewes were randomly allocated into two groups of seven animals each: GI ( n = 7; Control), and GII ( n = 7; walking stress). The animals were stall-fed with a diet consisting of 70% roughage and 30% concentrate. Both GI and GII ewes had uniform access to feed and water. The walking stress group (GII) ewes were made to walk 14 km in two spans between 0900 and 1500 hours with 1 h 30 min for each span (7 km) of walking. The ewes subjected to walking stress (GII) were prevented from grazing by applying a face mask made of cotton thread. The study was conducted for a period of two estrous cycles (35 days) during the autumn season (October-November). Physiological responses were recorded twice daily at 0800 and 1400 hours at weekly intervals. Blood samples were collected from the jugular vein at weekly intervals to study the effects of walking stress on blood biochemical and endocrine parameters. The results indicate that walking stress had significant ( P ewes have the capability to adapt to long-distance walking, and that adrenal and thyroid gland hormones play a significant role in such adaptation.

Dynamic Nature of Noncoding RNA Regulation of Adaptive Immune Response

Directory of Open Access Journals (Sweden)

Franca Citarella

2013-08-01

Full Text Available Immune response plays a fundamental role in protecting the organism from infections; however, dysregulation often occurs and can be detrimental for the organism, leading to a variety of immune-mediated diseases. Recently our understanding of the molecular and cellular networks regulating the immune response, and, in particular, adaptive immunity, has improved dramatically. For many years, much of the focus has been on the study of protein regulators; nevertheless, recent evidence points to a fundamental role for specific classes of noncoding RNAs (ncRNAs in regulating development, activation and homeostasis of the immune system. Although microRNAs (miRNAs are the most comprehensive and well-studied, a number of reports suggest the exciting possibility that long ncRNAs (lncRNAs could mediate host response and immune function. Finally, evidence is also accumulating that suggests a role for miRNAs and other small ncRNAs in autocrine, paracrine and exocrine signaling events, thus highlighting an elaborate network of regulatory interactions mediated by different classes of ncRNAs during immune response. This review will explore the multifaceted roles of ncRNAs in the adaptive immune response. In particular, we will focus on the well-established role of miRNAs and on the emerging role of lncRNAs and circulating ncRNAs, which all make indispensable contributions to the understanding of the multilayered modulation of the adaptive immune response.

A model for homeopathic remedy effects: low dose nanoparticles, allostatic cross-adaptation, and time-dependent sensitization in a complex adaptive system

Directory of Open Access Journals (Sweden)

Bell Iris R

2012-10-01

Full Text Available Abstract Background This paper proposes a novel model for homeopathic remedy action on living systems. Research indicates that homeopathic remedies (a contain measurable source and silica nanoparticles heterogeneously dispersed in colloidal solution; (b act by modulating biological function of the allostatic stress response network (c evoke biphasic actions on living systems via organism-dependent adaptive and endogenously amplified effects; (d improve systemic resilience. Discussion The proposed active components of homeopathic remedies are nanoparticles of source substance in water-based colloidal solution, not bulk-form drugs. Nanoparticles have unique biological and physico-chemical properties, including increased catalytic reactivity, protein and DNA adsorption, bioavailability, dose-sparing, electromagnetic, and quantum effects different from bulk-form materials. Trituration and/or liquid succussions during classical remedy preparation create “top-down” nanostructures. Plants can biosynthesize remedy-templated silica nanostructures. Nanoparticles stimulate hormesis, a beneficial low-dose adaptive response. Homeopathic remedies prescribed in low doses spaced intermittently over time act as biological signals that stimulate the organism’s allostatic biological stress response network, evoking nonlinear modulatory, self-organizing change. Potential mechanisms include time-dependent sensitization (TDS, a type of adaptive plasticity/metaplasticity involving progressive amplification of host responses, which reverse direction and oscillate at physiological limits. To mobilize hormesis and TDS, the remedy must be appraised as a salient, but low level, novel threat, stressor, or homeostatic disruption for the whole organism. Silica nanoparticles adsorb remedy source and amplify effects. Properly-timed remedy dosing elicits disease-primed compensatory reversal in direction of maladaptive dynamics of the allostatic network, thus promoting

Ebola Virus Altered Innate and Adaptive Immune Response Signalling Pathways: Implications for Novel Therapeutic Approaches.

Science.gov (United States)

Kumar, Anoop

2016-01-01

Ebola virus (EBOV) arise attention for their impressive lethality by the poor immune response and high inflammatory reaction in the patients. It causes a severe hemorrhagic fever with case fatality rates of up to 90%. The mechanism underlying this lethal outcome is poorly understood. In 2014, a major outbreak of Ebola virus spread amongst several African countries, including Leone, Sierra, and Guinea. Although infections only occur frequently in Central Africa, but the virus has the potential to spread globally. Presently, there is no vaccine or treatment is available to counteract Ebola virus infections due to poor understanding of its interaction with the immune system. Accumulating evidence indicates that the virus actively alters both innate and adaptive immune responses and triggers harmful inflammatory responses. In the literature, some reports have shown that alteration of immune signaling pathways could be due to the ability of EBOV to interfere with dendritic cells (DCs), which link innate and adaptive immune responses. On the other hand, some reports have demonstrated that EBOV, VP35 proteins act as interferon antagonists. So, how the Ebola virus altered the innate and adaptive immune response signaling pathways is still an open question for the researcher to be explored. Thus, in this review, I try to summarize the mechanisms of the alteration of innate and adaptive immune response signaling pathways by Ebola virus which will be helpful for designing effective drugs or vaccines against this lethal infection. Further, potential targets, current treatment and novel therapeutic approaches have also been discussed.

Dose-rate effect of adaptive response of apoptosis and cell cycle progression induced by low-dose ionizing radiation in EL-4 lymphoma cells in vitro

International Nuclear Information System (INIS)

Liu Shuchun; Lu Zhe; Li Yanbo; Kang Shunai; Gong Shouliang; Zhao Wenju

2008-01-01

Objective: To observe the dose-rate effect of adaptive response of apoptosis and cell cycle progression induced by low-dose ionizing radiation in EL-4 lymphoma cells in vitro in order to reveal the possible mechanism of biological effect and adaptive response induced by low dose radiation. Methods: The experiment was divided into D2 (challenging dose), D1 (inductive dose) + D2 and sham-irradiation groups. EL-4 lymphoma cells were irradiated with D1 (75 mGy, 6.25-200.00 mGy·mm -1 ) and D2(1.5 Gy, 287 mGy·min -1 ), the time interval between D1 and D2 was 6 h. The percentage of apoptosis and each cell cycle phase were measured with flow cytometry. Results: When the dose rates of D1 were 6.25-50.00 mGy·min -1 , the percentages of apoptosis in the D1 + D2 group were significantly lower than those in the D2 group (P 0 /G 1 phase cells decreased significantly (P -1 , D2 is 1.5 Gy (287 mGy·min -1 ), and the time interval between D1 and D2 is 6 h, the adaptive response of apoptosis and cell cycle progression in EL-4 lymphoma cells in vitro could be induced. (authors)

Low-Dose Ionizing Radiation Affects Mesenchymal Stem Cells via Extracellular Oxidized Cell-Free DNA: A Possible Mediator of Bystander Effect and Adaptive Response

Directory of Open Access Journals (Sweden)

V. A. Sergeeva

2017-01-01

Full Text Available We have hypothesized that the adaptive response to low doses of ionizing radiation (IR is mediated by oxidized cell-free DNA (cfDNA fragments. Here, we summarize our experimental evidence for this model. Studies involving measurements of ROS, expression of the NOX (superoxide radical production, induction of apoptosis and DNA double-strand breaks, antiapoptotic gene expression and cell cycle inhibition confirm this hypothesis. We have demonstrated that treatment of mesenchymal stem cells (MSCs with low doses of IR (10 cGy leads to cell death of part of cell population and release of oxidized cfDNA. cfDNA has the ability to penetrate into the cytoplasm of other cells. Oxidized cfDNA, like low doses of IR, induces oxidative stress, ROS production, ROS-induced oxidative modifications of nuclear DNA, DNA breaks, arrest of the cell cycle, activation of DNA reparation and antioxidant response, and inhibition of apoptosis. The MSCs pretreated with low dose of irradiation or oxidized cfDNA were equally effective in induction of adaptive response to challenge further dose of radiation. Our studies suggest that oxidized cfDNA is a signaling molecule in the stress signaling that mediates radiation-induced bystander effects and that it is an important component of the development of radioadaptive responses to low doses of IR.

Non-climatic thermal adaptation: implications for species' responses to climate warming.

Science.gov (United States)

Marshall, David J; McQuaid, Christopher D; Williams, Gray A

2010-10-23

There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky-eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models.

Mechanical Adaptability of the MMP-Responsive Film Improves the Functionality of Endothelial Cell Monolayer.

Science.gov (United States)

Hu, Mi; Chang, Hao; Zhang, He; Wang, Jing; Lei, Wen-Xi; Li, Bo-Chao; Ren, Ke-Feng; Ji, Jian

2017-07-01

Extracellular matrix and cells are inherent in coordinating and adapting to each other during all physiological and pathological processes. Synthetic materials, however, show rarely reciprocal and spatiotemporal responses to cells, and lacking self-adapting properties as well. Here, a mechanical adaptability based on the matrix metalloproteinase (MMPs) sensitive polyelectrolyte film is reported. Poly-lysine (PLL) and methacrylated hyaluronic acid (HA-MA) nanolayers are employed to build the thin film through the layer-by-layer assembly, and it is further crosslinked using MMP sensitive peptides, which endows the films with changeable mechanical properties in response to MMPs. It is demonstrated that stiffness of the (PLL/HA-MA) films increases with the crosslinking, and then decreases in response to a treatment of enzyme. Consequently, the crosslinked (PLL/HA-MA) films reveal effective growth of endothelial cells (ECs), leading to fast formation of EC monolayer. Importantly, significantly improved endothelial function of the EC monolayer, which is characterized by integrity, biomolecules release, expression of function related gene, and antithrombotic properties, is achieved along with the decrosslinking of the film because of EC-secreted MMPs. These results suggest that mechanical adaptability of substrate in Young's modulus plays a significant role in endothelial progression, which shows great application potential in tissue engineering, regenerative medicine, and organ-on-a-chip. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cytogenetic adaptive response induced by pre-exposure in human lymphocytes and marrow cells of mice

International Nuclear Information System (INIS)

Zhang Lianzhen; Deng Zhicheng

1993-01-01

The cytogenetic adaptive response induced by pre-exposure in human lymphocytes and marrow cells of mice were studied. The results of this study showed that human lymphocytes in vitro and mouse marrow cells in vivo can become adapted to low-level irradiation from 3 H-TdR or exposure to a low dose of X-or γ-irradiation, so that they become less sensitive to the chromosomal damage effects of subsequent exposures. (4 tabs.)

Arousal regulation and affective adaptation to human responsiveness by a robot that explores and learns a novel environment.

Science.gov (United States)

Hiolle, Antoine; Lewis, Matthew; Cañamero, Lola

2014-01-01

In the context of our work in developmental robotics regarding robot-human caregiver interactions, in this paper we investigate how a "baby" robot that explores and learns novel environments can adapt its affective regulatory behavior of soliciting help from a "caregiver" to the preferences shown by the caregiver in terms of varying responsiveness. We build on two strands of previous work that assessed independently (a) the differences between two "idealized" robot profiles-a "needy" and an "independent" robot-in terms of their use of a caregiver as a means to regulate the "stress" (arousal) produced by the exploration and learning of a novel environment, and (b) the effects on the robot behaviors of two caregiving profiles varying in their responsiveness-"responsive" and "non-responsive"-to the regulatory requests of the robot. Going beyond previous work, in this paper we (a) assess the effects that the varying regulatory behavior of the two robot profiles has on the exploratory and learning patterns of the robots; (b) bring together the two strands previously investigated in isolation and take a step further by endowing the robot with the capability to adapt its regulatory behavior along the "needy" and "independent" axis as a function of the varying responsiveness of the caregiver; and (c) analyze the effects that the varying regulatory behavior has on the exploratory and learning patterns of the adaptive robot.

Command Resiliency: An Adaptive Response Strategy for Complex Incidents

National Research Council Canada - National Science Library

Pfeifer, Joseph W

2005-01-01

.... Unless organizations develop a resilient response strategy that can adapt organizational and operational elements to respond to new terrorist incidents, they will find themselves with the same...

Guest-responsive structural adaptation of a rationally-designed ...

Indian Academy of Sciences (India)

adaptability of the TB core to undergo subtle structural changes in response to the guest that is included. The structural ... we report the design, synthesis and inclusion behaviour of a novel ..... Based on a rational design, we have shown from ...

Is the bitter rejection response always adaptive?

Science.gov (United States)

Glendinning, J I

1994-12-01

The bitter rejection response consists of a suite of withdrawal reflexes and negative affective responses. It is generally assumed to have evolved as a way to facilitate avoidance of foods that are poisonous because they usually taste bitter to humans. Using previously published studies, the present paper examines the relationship between bitterness and toxicity in mammals, and then assesses the ecological costs and benefits of the bitter rejection response in carnivorous, omnivorous, and herbivorous (grazing and browsing) mammals. If the bitter rejection response accurately predicts the potential toxicity of foods, then one would expect the threshold for the response to be lower for highly toxic compounds than for nontoxic compounds. The data revealed no such relationship. Bitter taste thresholds varied independently of toxicity thresholds, indicating that the bitter rejection response is just as likely to be elicited by a harmless bitter food as it is by a harmful one. Thus, it is not necessarily in an animal's best interest to have an extremely high or low bitter threshold. Based on this observation, it was hypothesized that the adaptiveness of the bitter rejection response depends upon the relative occurrence of bitter and potentially toxic compounds in an animal's diet. Animals with a relatively high occurrence of bitter and potentially toxic compounds in their diet (e.g., browsing herbivores) were predicted to have evolved a high bitter taste threshold and tolerance to dietary poisons. Such an adaptation would be necessary because a browser cannot "afford" to reject all foods that are bitter and potentially toxic without unduly restricting its dietary options. At the other extreme, animals that rarely encounter bitter and potentially toxic compounds in their diet (e.g., carnivores) were predicted to have evolved a low bitter threshold. Carnivores could "afford" to utilize such a stringent rejection mechanism because foods containing bitter and potentially

Saccharomyces cerevisiae has distinct adaptive responses to both hydrogen peroxide and menadione.

OpenAIRE

Jamieson, D J

1992-01-01

Treatment of Saccharomyces cerevisiae cells with low concentrations of either hydrogen peroxide or menadione (a superoxide-generating agent) induces adaptive responses which protect cells from the lethal effects of subsequent challenge with higher concentrations of these oxidants. Pretreatment with menadione is protective against cell killing by hydrogen peroxide; however, pretreatment with hydrogen peroxide is unable to protect cells from subsequent challenge with menadione. This suggests th...

Effectiveness of Instruction and Video Feedback on Staff's Use of Prompts and Children's Adaptive Responses during One-to-One Training in Children with Severe to Profound Intellectual Disability

Science.gov (United States)

van Vonderen, Annemarie; de Swart, Charlotte; Didden, Robert

2010-01-01

Although relatively many studies have addressed staff training and its effect on trainer behavior, the effects of staff training on trainee's adaptive behaviors have seldomly been examined. We therefore assessed effectiveness of staff training, consisting of instruction and video feedback, on (a) staff's response prompting, and (b) staff's trainer…

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

OpenAIRE

Apostolos Chatzitomaris; Rudolf Hoermann; John E. Midgley; Steffen Hering; Aline Urban; Barbara Dietrich; Assjana Abood; Harald H. Klein; Harald H. Klein; Johannes W. Dietrich; Johannes W. Dietrich

2017-01-01

The hypothalamus–pituitary–thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTI...

Testing the Nanoparticle-Allostatic Cross Adaptation-Sensitization Model for Homeopathic Remedy Effects

Science.gov (United States)

Bell, Iris R.; Koithan, Mary; Brooks, Audrey J.

2012-01-01

Key concepts of the Nanoparticle-Allostatic Cross-Adaptation-Sensitization (NPCAS) Model for the action of homeopathic remedies in living systems include source nanoparticles as low level environmental stressors, heterotypic hormesis, cross-adaptation, allostasis (stress response network), time-dependent sensitization with endogenous amplification and bidirectional change, and self-organizing complex adaptive systems. The model accommodates the requirement for measurable physical agents in the remedy (source nanoparticles and/or source adsorbed to silica nanoparticles). Hormetic adaptive responses in the organism, triggered by nanoparticles; bipolar, metaplastic change, dependent on the history of the organism. Clinical matching of the patient’s symptom picture, including modalities, to the symptom pattern that the source material can cause (cross-adaptation and cross-sensitization). Evidence for nanoparticle-related quantum macro-entanglement in homeopathic pathogenetic trials. This paper examines research implications of the model, discussing the following hypotheses: Variability in nanoparticle size, morphology, and aggregation affects remedy properties and reproducibility of findings. Homeopathic remedies modulate adaptive allostatic responses, with multiple dynamic short- and long-term effects. Simillimum remedy nanoparticles, as novel mild stressors corresponding to the organism’s dysfunction initiate time-dependent cross-sensitization, reversing the direction of dysfunctional reactivity to environmental stressors. The NPCAS model suggests a way forward for systematic research on homeopathy. The central proposition is that homeopathic treatment is a form of nanomedicine acting by modulation of endogenous adaptation and metaplastic amplification processes in the organism to enhance long-term systemic resilience and health. PMID:23290882

Evolution of plasticity and adaptive responses to climate change along climate gradients.

Science.gov (United States)

Kingsolver, Joel G; Buckley, Lauren B

2017-08-16

The relative contributions of phenotypic plasticity and adaptive evolution to the responses of species to recent and future climate change are poorly understood. We combine recent (1960-2010) climate and phenotypic data with microclimate, heat balance, demographic and evolutionary models to address this issue for a montane butterfly, Colias eriphyle , along an elevational gradient. Our focal phenotype, wing solar absorptivity, responds plastically to developmental (pupal) temperatures and plays a central role in thermoregulatory adaptation in adults. Here, we show that both the phenotypic and adaptive consequences of plasticity vary with elevation. Seasonal changes in weather generate seasonal variation in phenotypic selection on mean and plasticity of absorptivity, especially at lower elevations. In response to climate change in the past 60 years, our models predict evolutionary declines in mean absorptivity (but little change in plasticity) at high elevations, and evolutionary increases in plasticity (but little change in mean) at low elevation. The importance of plasticity depends on the magnitude of seasonal variation in climate relative to interannual variation. Our results suggest that selection and evolution of both trait means and plasticity can contribute to adaptive response to climate change in this system. They also illustrate how plasticity can facilitate rather than retard adaptive evolutionary responses to directional climate change in seasonal environments. © 2017 The Author(s).

Induction of adaptive response in human blood lymphocytes exposed to radiofrequency radiation.

Science.gov (United States)

Sannino, Anna; Sarti, Maurizio; Reddy, Siddharth B; Prihoda, Thomas J; Vijayalaxmi; Scarfì, Maria Rosaria

2009-06-01

The incidence of micronuclei was evaluated to assess the induction of an adaptive response to non-ionizing radiofrequency (RF) radiation in peripheral blood lymphocytes collected from five different human volunteers. After stimulation with phytohemagglutinin for 24 h, the cells were exposed to an adaptive dose of 900 MHz RF radiation used for mobile communications (at a peak specific absorption rate of 10 W/kg) for 20 h and then challenged with a single genotoxic dose of mitomycin C (100 ng/ml) at 48 h. Lymphocytes were collected at 72 h to examine the frequency of micronuclei in cytokinesis-blocked binucleated cells. Cells collected from four donors exhibited the induction of adaptive response (i.e., responders). Lymphocytes that were pre-exposed to 900 MHz RF radiation had a significantly decreased incidence of micronuclei induced by the challenge dose of mitomycin C compared to those that were not pre-exposed to 900 MHz RF radiation. These preliminary results suggested that the adaptive response can be induced in cells exposed to non-ionizing radiation. A similar phenomenon has been reported in cells as well as in animals exposed to ionizing radiation in several earlier studies. However, induction of adaptive response was not observed in the remaining donor (i.e., non-responder). The incidence of micronuclei induced by the challenge dose of mitomycin C was not significantly different between the cells that were pre-exposed and unexposed to 900 MHz RF radiation. Thus the overall data indicated the existence of heterogeneity in the induction of an adaptive response between individuals exposed to RF radiation and showed that the less time-consuming micronucleus assay can be used to determine whether an individual is a responder or non-responder.

Computerized Adaptive Test (CAT) Applications and Item Response Theory Models for Polytomous Items

Science.gov (United States)

Aybek, Eren Can; Demirtasli, R. Nukhet

2017-01-01

This article aims to provide a theoretical framework for computerized adaptive tests (CAT) and item response theory models for polytomous items. Besides that, it aims to introduce the simulation and live CAT software to the related researchers. Computerized adaptive test algorithm, assumptions of item response theory models, nominal response…

Repeated exposure of human fibroblasts to ionizing radiation reveals an adaptive response that is not mediated by interleukin-6 or TGF-β

International Nuclear Information System (INIS)

Dieriks, Birger; De Vos, Winnok; Baatout, Sarah; Van Oostveldt, Patrick

2011-01-01

Exposing cells to a low dose can protect them against a subsequent higher exposure. This phenomenon is known as adaptive response and is frequently observed in a variety of cells. Even though similarities are suspected with other non-targeted effects, such as bystander effects, the exact mechanism behind adaptive response is not fully clarified. In this study human primary fibroblasts were tested for their response to ionizing radiation (IR) after administrating a low priming dose (0.1-0.5 Gy). Both the abundance of γH2AX as a marker for double-stranded breaks and the levels of cytokines, secreted in the medium, were monitored in time. Upon challenge, IR-primed cells showed modified γH2AX spot size distributions and altered repair kinetics, consistent with an adaptive response. In addition, 24 h after priming with IR, four cytokines were significantly upregulated in the medium - GM-CSF (1.33x); IL6 (4.24x); IL8 (1.33x); TGF-β (1.46x). In order to mimick the protective effect of IR priming, we primed the cells with either IL6 or TGF-β. This did not elicit an altered γH2AX response as observed in IR-primed cells, indicating that the adaptive response in these primary fibroblasts is regulated in an IL-6 and TGF-β independent manner.

Variation in rhodopsin kinase expression alters the dim flash response shut off and the light adaptation in rod photoreceptors.

Science.gov (United States)

Sakurai, Keisuke; Young, Joyce E; Kefalov, Vladimir J; Khani, Shahrokh C

2011-08-29

Rod photoreceptors are exquisitely sensitive light detectors that function in dim light. The timely inactivation of their light responses is critical for the ability of rods to reliably detect and count photons. A key step in the inactivation of the rod transduction is the phosphorylation of the rod visual pigment, rhodopsin, catalyzed by G-protein-dependent receptor kinase 1 (GRK1). Absence of GRK1 greatly prolongs the photoreceptors' light response and enhances their susceptibility to degeneration. This study examined the light responses from mouse rods expressing various levels of GRK1 to evaluate how their function is modulated by rhodopsin inactivation. Transretinal and single-cell rod electrophysiological recordings were obtained from several strains of mice expressing GRK1 at 0.3- to 3-fold the wild-type levels. The effect of GRK1 expression level on the function of mouse rods was examined in darkness and during background adaptation. Altering the expression of GRK1 from 0.3- to 3-fold that in wild-type rods had little effect on the single photon response amplitude. Notably, increasing the expression level of GRK1 accelerated the dim flash response shut off but had no effect on the saturated response shut off. Additionally, GRK1 excess abolished the acceleration of saturated responses shut off during light adaptation. These results demonstrate that rhodopsin inactivation can modulate the kinetics of recovery from dim light stimulation. More importantly, the ratio of rhodopsin kinase to its modulator recoverin appears critical for the proper adaptation of rods and the acceleration of their response shut off in background light.

Adaptive response to ionizing radiation induced by low doses of gamma rays in human cell lines

International Nuclear Information System (INIS)

Seong, Jinsil; Chang, Ok Suh; Gwi, Eon Kim

1995-01-01

Purpose: The aim of this study was to investigate whether the adaptive response could be induced in human lymphoblastoid cell lines and human tumor cell lines. The time necessary for the expression of the adaptive response was also investigated. Materials and Methods: Three lymphoblastoid cell lines from ataxia telangiectasia (AT) homozygote (GM 1526), AT heterozygote (GM 3382), and normal individual (3402p) and two hepatoma cell lines, Hep G2 and Hep 3B, were used in this study. Experiments were carried out by delivering 0.01 Gy followed by 0.5 Gy of gamma radiation to the exponentially growing cells. The time necessary for the expression of the adaptive response was determined by varying the time interval between the two doses from 1 to 72 h. In some experiments, 3-aminobenzamide, a potent inhibitor of poly (ADP-ribose) polymerase, was added immediately after the 0.5 Gy exposure. The cultures were fixed 30 min (for the G 2 chromatid) and 6 h (for the S chromatid) after the 0.5 Gy exposure. Metaphase chromosome assay was carried out to score chromatid breaks as an end point. Results: A prior exposure to 0.01 Gy of gamma rays significantly reduced the number of chromatid breaks induced by subsequent higher doses (0.5 Gy) in all the tested cell lines. The magnitude of the adaptive response was similar among the cell lines despite their different radiosensitivities. In the G 2 chromatids, the adaptive response was observed both at short-time intervals, as early as 1 h, and at long-time intervals. In the S chromatids, however, the adaptive response was shown only at long-time intervals. When 3-aminobenzamide was added after the 0.5 Gy, the adaptive responses were abolished in all the experimental groups. Conclusion: The adaptive response was observed in human lymphoblastoid cell lines and hepatoma cell lines. The magnitude of the adaptive response did not seem to be related to the radiosensitivity of the cells. The elimination of the adaptive response with 3

Human Lung Cancer Risks from Radon – Part III - Evidence of Influence of Combined Bystander and Adaptive Response Effects on Radon Case-Control Studies - A Microdose Analysis

Science.gov (United States)

Leonard, Bobby E.; Thompson, Richard E.; Beecher, Georgia C.

2012-01-01

Since the publication of the BEIR VI (1999) report on health risks from radon, a significant amount of new data has been published showing various mechanisms that may affect the ultimate assessment of radon as a carcinogen, in particular the potentially deleterious Bystander Effect (BE) and the potentially beneficial Adaptive Response radio-protection (AR). The case-control radon lung cancer risk data of the pooled 13 European countries radon study (Darby et al 2005, 2006) and the 8 North American pooled study (Krewski et al 2005, 2006) have been evaluated. The large variation in the odds ratios of lung cancer from radon risk is reconciled, based on the large variation in geological and ecological conditions and variation in the degree of adaptive response radio-protection against the bystander effect induced lung damage. The analysis clearly shows Bystander Effect radon lung cancer induction and Adaptive Response reduction in lung cancer in some geographical regions. It is estimated that for radon levels up to about 400 Bq m−3 there is about a 30% probability that no human lung cancer risk from radon will be experienced and a 20% probability that the risk is below the zero-radon, endogenic spontaneous or perhaps even genetically inheritable lung cancer risk rate. The BEIR VI (1999) and EPA (2003) estimates of human lung cancer deaths from radon are most likely significantly excessive. The assumption of linearity of risk, by the Linear No-Threshold Model, with increasing radon exposure is invalid. PMID:22942874

Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies

Science.gov (United States)

Finsterwald, Charles; Alberini, Cristina M.

2013-01-01

A proper response against stressors is critical for survival. In mammals, the stress response is primarily mediated by secretion of glucocorticoids via the hypothalamic-pituitaryadrenocortical (HPA) axis and release of catecholamines through adrenergic neurotransmission. Activation of these pathways results in a quick physical response to the stress and, in adaptive conditions, mediates long-term changes in the brain that lead to the formation of long-term memories of the experience. These long-term memories are an essential adaptive mechanism that allows an animal to effectively face similar demands again. Indeed, a moderate stress level has a strong positive effect on memory and cognition, as a single arousing or moderately stressful event can be remembered for up to a lifetime. Conversely, exposure to extreme, traumatic, or chronic stress can have the opposite effect and cause memory loss, cognitive impairments, and stress-related psychopathologies such as anxiety disorders, depression and post-traumatic stress disorder (PTSD). While more effort has been devoted to the understanding of the effects of the negative effects of chronic stress, much less has been done thus far on the identification of the mechanisms engaged in the brain when stress promotes long-term memory formation. Understanding these mechanisms will provide critical information for use in ameliorating memory processes in both normal and pathological conditions. Here, we will review the role of glucocorticoids and glucocorticoid receptors (GRs) in memory formation and modulation. Furthermore, we will discuss recent findings on the molecular cascade of events underlying the effect of GR activation in adaptive levels of stress that leads to strong, long-lasting memories. Our recent data indicate that the positive effects of GR activation on memory consolidation critically engage the brain-derived neurotrophic factor (BDNF) pathway. We propose and will discuss the hypothesis that stress promotes the

Molecular characterization of an adaptive response to alkylating agents in the opportunistic pathogen Aspergillus fumigatus.

Science.gov (United States)

O'Hanlon, Karen A; Margison, Geoffrey P; Hatch, Amy; Fitzpatrick, David A; Owens, Rebecca A; Doyle, Sean; Jones, Gary W

2012-09-01

An adaptive response to alkylating agents based upon the conformational change of a methylphosphotriester (MPT) DNA repair protein to a transcriptional activator has been demonstrated in a number of bacterial species, but this mechanism appears largely absent from eukaryotes. Here, we demonstrate that the human pathogen Aspergillus fumigatus elicits an adaptive response to sub-lethal doses of the mono-functional alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). We have identified genes that encode MPT and O(6)-alkylguanine DNA alkyltransferase (AGT) DNA repair proteins; deletions of either of these genes abolish the adaptive response and sensitize the organism to MNNG. In vitro DNA repair assays confirm the ability of MPT and AGT to repair methylphosphotriester and O(6)-methylguanine lesions respectively. In eukaryotes, the MPT protein is confined to a select group of fungal species, some of which are major mammalian and plant pathogens. The evolutionary origin of the adaptive response is bacterial and rooted within the Firmicutes phylum. Inter-kingdom horizontal gene transfer between Firmicutes and Ascomycete ancestors introduced the adaptive response into the Fungal kingdom. Our data constitute the first detailed characterization of the molecular mechanism of the adaptive response in a lower eukaryote and has applications for development of novel fungal therapeutics targeting this DNA repair system.

Molecular characterization of an adaptive response to alkylating agents in the opportunistic pathogen Aspergillus fumigatus

Science.gov (United States)

O’Hanlon, Karen A.; Margison, Geoffrey P.; Hatch, Amy; Fitzpatrick, David A.; Owens, Rebecca A.; Doyle, Sean; Jones, Gary W.

2012-01-01

An adaptive response to alkylating agents based upon the conformational change of a methylphosphotriester (MPT) DNA repair protein to a transcriptional activator has been demonstrated in a number of bacterial species, but this mechanism appears largely absent from eukaryotes. Here, we demonstrate that the human pathogen Aspergillus fumigatus elicits an adaptive response to sub-lethal doses of the mono-functional alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). We have identified genes that encode MPT and O6-alkylguanine DNA alkyltransferase (AGT) DNA repair proteins; deletions of either of these genes abolish the adaptive response and sensitize the organism to MNNG. In vitro DNA repair assays confirm the ability of MPT and AGT to repair methylphosphotriester and O6-methylguanine lesions respectively. In eukaryotes, the MPT protein is confined to a select group of fungal species, some of which are major mammalian and plant pathogens. The evolutionary origin of the adaptive response is bacterial and rooted within the Firmicutes phylum. Inter-kingdom horizontal gene transfer between Firmicutes and Ascomycete ancestors introduced the adaptive response into the Fungal kingdom. Our data constitute the first detailed characterization of the molecular mechanism of the adaptive response in a lower eukaryote and has applications for development of novel fungal therapeutics targeting this DNA repair system. PMID:22669901

On the limitations of fixed-step-size adaptive methods with response confidence.

Science.gov (United States)

Hsu, Yung-Fong; Chin, Ching-Lan

2014-05-01

The family of (non-parametric, fixed-step-size) adaptive methods, also known as 'up-down' or 'staircase' methods, has been used extensively in psychophysical studies for threshold estimation. Extensions of adaptive methods to non-binary responses have also been proposed. An example is the three-category weighted up-down (WUD) method (Kaernbach, 2001) and its four-category extension (Klein, 2001). Such an extension, however, is somewhat restricted, and in this paper we discuss its limitations. To facilitate the discussion, we characterize the extension of WUD by an algorithm that incorporates response confidence into a family of adaptive methods. This algorithm can also be applied to two other adaptive methods, namely Derman's up-down method and the biased-coin design, which are suitable for estimating any threshold quantiles. We then discuss via simulations of the above three methods the limitations of the algorithm. To illustrate, we conduct a small scale of experiment using the extended WUD under different response confidence formats to evaluate the consistency of threshold estimation. © 2013 The British Psychological Society.

Adaptive response and genomic instability: allosteric response of genome to negative impact

International Nuclear Information System (INIS)

Sasaki, Masao S.

2010-01-01

Currently, there is an upsurge concern on the unique response of living cells to low dose ionizing radiation for its inconformity to the existing paradigm of the biological action of radiation and its impact on the current understanding of risk evaluation of health effect of radiation in our workplace and environment. For the allosteric response to have significance, the cells must have an excellent sensing mechanism to discriminate tolerable and intolerable signals. In a series of experiments with mammalian, including human, cells, we demonstrated a novel sensing and signaling mechanism in the low-dose irradiated cells that was mediated by a PKCα-p3BMAPK-PLCδ1 feedback regulatory loop. Upon irradiation, PKCα is immediately activated, which in turn activate p38MAPK. The activation of p38MAPK is feedbacked to the activation of PKCα via PLCδ1, which catalyzes the hydrolysis of PtdInsP2 to generate PKCα-directed second messengers DAG and lnsP3. At low doses, the PKCα and p38MAPK continue to be activated for long time through this feedback loop, but when the cells encounter the high dose (>10 cGy or equivalent), the feedback loop is immediately comes to shutdown by deprivation of PKCα protein, known as down-regulation of PKC signaling. Thus, PKCα plays a key role in the long lasting nature of adaptive response to low doses and a binary switch to the genomic instability by too much signals. Tumor suppressor protein, p53, is a downstream effecter

Inducible protective processes in animal systems XIV: Cytogenetic adaptive response induced by EMS or MMS in bone marrow cells of diabetic mouse

Directory of Open Access Journals (Sweden)

B.B. Dada Khalandar

2016-04-01

Conclusion: (1 Methylating agents are a more effective inducer of adaptive response than ethylating agents in diabetic mouse. (2 Further, it is interesting to note that the percentage reduction of chromosomal breaks in diabetics is comparatively much less than in non diabetic mouse, inferring that there is variation in adaptive response between diseased and non diseased condition.

Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies.

Science.gov (United States)

Finsterwald, Charles; Alberini, Cristina M

2014-07-01

A proper response against stressors is critical for survival. In mammals, the stress response is primarily mediated by secretion of glucocorticoids via the hypothalamic-pituitary-adrenocortical (HPA) axis and release of catecholamines through adrenergic neurotransmission. Activation of these pathways results in a quick physical response to the stress and, in adaptive conditions, mediates long-term changes in the brain that lead to the formation of long-term memories of the experience. These long-term memories are an essential adaptive mechanism that allows an animal to effectively face similar demands again. Indeed, a moderate stress level has a strong positive effect on memory and cognition, as a single arousing or moderately stressful event can be remembered for up to a lifetime. Conversely, exposure to extreme, traumatic, or chronic stress can have the opposite effect and cause memory loss, cognitive impairments, and stress-related psychopathologies such as anxiety disorders, depression and post-traumatic stress disorder (PTSD). While more effort has been devoted to the understanding of the negative effects of chronic stress, much less has been done thus far on the identification of the mechanisms engaged in the brain when stress promotes long-term memory formation. Understanding these mechanisms will provide critical information for use in ameliorating memory processes in both normal and pathological conditions. Here, we will review the role of glucocorticoids and glucocorticoid receptors (GRs) in memory formation and modulation. Furthermore, we will discuss recent findings on the molecular cascade of events underlying the effect of GR activation in adaptive levels of stress that leads to strong, long-lasting memories. Our recent data indicate that the positive effects of GR activation on memory consolidation critically engage the brain-derived neurotrophic factor (BDNF) pathway. We propose and will discuss the hypothesis that stress promotes the formation of

A biological-based model that links genomic instability, bystander effects, and adaptive response

International Nuclear Information System (INIS)

Scott, B.R.

2004-01-01

This paper links genomic instability, bystander effects, and adaptive response in mammalian cell communities via a novel biological-based, dose-response model called NEOTRANS 3 . The model is an extension of the NEOTRANS 2 model that addressed stochastic effects (genomic instability, mutations, and neoplastic transformation) associated with brief exposure to low radiation doses. With both models, ionizing radiation produces DNA damage in cells that can be associated with varying degrees of genomic instability. Cells with persistent problematic instability (PPI) are mutants that arise via misrepair of DNA damage. Progeny of PPI cells also have PPI and can undergo spontaneous neoplastic transformation. Unlike NEOTRANS 2 , with NEOTRANS 3 newly induced mutant PPI cells and their neoplastically transformed progeny can be suppressed via our previously introduced protective apoptosis-mediated (PAM) process, which can be activated by low linear energy transfer (LET) radiation. However, with NEOTRANS 3 (which like NEOTRANS 2 involves cross-talk between nongenomically compromised [e.g., nontransformed, nonmutants] and genomically compromised [e.g., mutants, transformants, etc.] cells), it is assumed that PAM is only activated over a relatively narrow, dose-rate-dependent interval (D PAM ,D off ); where D PAM is a small stochastic activation threshold, and D off is the stochastic dose above which PAM does not occur. PAM cooperates with activated normal DNA repair and with activated normal apoptosis in guarding against genomic instability. Normal repair involves both error-free repair and misrepair components. Normal apoptosis and the error-free component of normal repair protect mammals by preventing the occurrence of mutant cells. PAM selectively removes mutant cells arising via the misrepair component of normal repair, selectively removes existing neoplastically transformed cells, and probably selectively removes other genomically compromised cells when it is activated

Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats.

Science.gov (United States)

Lai, Sarah W; de Heuvel, Elaine; Wallace, Laurie E; Hartmann, Bolette; Holst, Jens J; Brindle, Mary E; Chelikani, Prasanth K; Sigalet, David L

2017-01-01

To determine the effects of exogenous glucagon-like peptide-2 (GLP-2), with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats. GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS). However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear. Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB) (n = 8), TB + GLP-2 (2.5 nmol/kg/h, n = 8), SBS (n = 5), or SBS + GLP-2 (2.5 nmol/kg/h, n = 9). SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5) and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS), plasma glucose, gut hormones, and body composition. Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2), increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss. Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy of further study.

Global transcriptional, physiological and metabolite analyses of Desulfovibrio vulgaris Hildenborough responses to salt adaptation

Energy Technology Data Exchange (ETDEWEB)

He, Z.; Zhou, A.; Baidoo, E.; He, Q.; Joachimiak, M. P.; Benke, P.; Phan, R.; Mukhopadhyay, A.; Hemme, C.L.; Huang, K.; Alm, E.J.; Fields, M.W.; Wall, J.; Stahl, D.; Hazen, T.C.; Keasling, J.D.; Arkin, A.P.; Zhou, J.

2009-12-01

The response of Desulfovibrio vulgaris Hildenborough to salt adaptation (long-term NaCl exposure) was examined by physiological, global transcriptional, and metabolite analyses. The growth of D. vulgaris was inhibited by high levels of NaCl, and the growth inhibition could be relieved by the addition of exogenous amino acids (e.g., glutamate, alanine, tryptophan) or yeast extract. Salt adaptation induced the expression of genes involved in amino acid biosynthesis and transport, electron transfer, hydrogen oxidation, and general stress responses (e.g., heat shock proteins, phage shock proteins, and oxidative stress response proteins). Genes involved in carbon metabolism, cell motility, and phage structures were repressed. Comparison of transcriptomic profiles of D. vulgaris responses to salt adaptation with those of salt shock (short-term NaCl exposure) showed some similarity as well as a significant difference. Metabolite assays showed that glutamate and alanine were accumulated under salt adaptation, suggesting that they may be used as osmoprotectants in D. vulgaris. A conceptual model is proposed to link the observed results to currently available knowledge for further understanding the mechanisms of D. vulgaris adaptation to elevated NaCl.

Adaptability: Conceptual and Empirical Perspectives on Responses to Change, Novelty and Uncertainty

Science.gov (United States)

Martin, Andrew J.; Nejad, Harry; Colmar, Susan; Liem, Gregory Arief D.

2012-01-01

Adaptability is proposed as individuals' capacity to constructively regulate psycho-behavioral functions in response to new, changing, and/or uncertain circumstances, conditions and situations. The present investigation explored the internal and external validity of an hypothesised adaptability scale. The sample comprised 2,731 high school…

Circumvention of camptothecin-induced resistance during the adaptive cellular stress response.

Science.gov (United States)

Tiligada, Ekaterini; Papamichael, Konstantinos; Vovou, Ioanna; Delitheos, Andreas

2006-01-01

Camptothecin-11 (CPT-11) induces the adaptive stress response in yeast, conferring resistance via not fully characterized mechanisms. This study aimed at exploring, pharmacologically, the mechanisms underlying the CPT-11-induced resistance in yeast. Post-logarithmic yeast cultures were submitted to heat shock following preconditioning with suramin and with CPT-11, either alone or in combination with suramin, cycloheximide, sodium molybdate, okadaic acid, or verapamil. The stress response was evaluated by determining cell viability after heat shock. Preconditioning with CPT-11 or suramin conferred thermotolerance to yeast cells. Co-administration of CPT-11 with suramin, cycloheximide or okadaic acid reversed the CPT-11-induced thermotolerant phenotype, while sodium molybdate and verapamil had no effect on CPT-11-induced resistance. The antagonistic effect of the thermotolerance-inducers and the possible contribution of topoisomerase II activity and post-translational modifications mediated by the phosphatases PP1/2A in CPT-11-induced resistance may have important implications on the acquisition of resistance to stress in eukaryotic cells.

Relationship between the adaptive response and bystander effect produced by single cell irradiation using a focused ultrasoft x-ray microbeam

International Nuclear Information System (INIS)

Wu, L.; Schettino, G.; Folkard, M.; Yu, Z.; Prise, K.; Michael, B.; Wang, Y.

2003-01-01

Full text: Using the cell killing method and our newly developed focused carbon-K ultrasoft X-rays, we tested for an interaction between bystander responses and adaptive responses by irradiating only one V79 cell in a population with a dose of 0.2 or 1Gy, combined with a conventional 240kVp X irradiation (0, 0.01, 0.05, 0.2 or 1Gy) 2 hours before or after bystander treatment. The clonogenic survival of V79 cells was precisely measured by a single cell revisiting assay after incubation for 3 days. Our results clearly showed that the cell killing by the bystander treatment could be reduced by about 5% if we treated the cells with a very low dose of conventional 240kVp X-rays of 0.01 or 0.05Gy (at which dose they only kill 1 or 2% cells in a population), whether the conventional dose was given before or after bystander irradiation. When the conventional dose was increased to 0.2 or 1Gy (at which dose they could kill about 10 or 25% V79 cells), no adaptive response was found if we treated the cells with conventional irradiation first and bystander irradiation afterwards. However, the adaptive responses observed when we irradiated a single cell within the whole cell population before 0.2 or 1Gy conventional irradiation was given. This showed that the bystander-mediated adaptive response could increase the cell survival by 5 or 8% respectively compared with the cell killing by conventional irradiation of 0.2 or 1Gy only. We also tested the distribution of dead clones in the microbeam dishes either for bystander irradiation only or combined with conventional X-rays. We did not find any distance relationship between the irradiated cell and non-irradiated cells, which was consistent with our previous bystander irradiation studies showing an equal probability of finding damaged clones any where in the scanned area of the dish

Cellular adaptation as an important response during chemical carcinogenesis

International Nuclear Information System (INIS)

Farber, E.

1992-01-01

Since disease processes are largely expressions of how living organisms react and respond to perturbations in the external and internal environments, adaptive or protective responses and their modulations and mechanisms are of the greatest concern in fundamental studies of disease pathogenesis. Such considerations are also of the greatest relevance in toxicology, including how living organisms respond to low levels of single and multiple xenobiotics and radiations. As the steps and mechanisms during cancer development are studied in greater depth, phenomena become apparent that suggest that adaptive reactions and responses may play important or even critical roles in the process of carcinogenesis. The question becomes whether the process of carcinogenesis is fundamentally an adversarial one (i.e., an abnormal cell in a vulnerable host), or is it more in the nature of a physiological selection or differentiation, which has survival value for the host as an adaptive phenomena? The very early initial interactions of mutagenic chemical carcinogens, radiations and viruses with DNA prejudice most to consider the adversarial 'abnormal' view as the appropriate one. Yet, the unusually common nature of the earliest altered rare cells that appear during carcinogenesis, their unusually bland nature, and their spontaneous differentiation to normal-appearing adult liver should be carefully considered

Enhancement of human adaptive immune responses by administration of a high-molecular-weight polysaccharide extract from the cyanobacterium Arthrospira platensis

DEFF Research Database (Denmark)

Pedersen, Morten Løbner; Walsted, Anette; Larsen, Rune

2008-01-01

The effect of consumption of Immulina, a high-molecular-weight polysaccharide extract from the cyanobacterium Arthrospira platensis, on adaptive immune responses was investigated by evaluation of changes in leukocyte responsiveness to two foreign recall antigens, Candida albicans (CA) and tetanus...

Gravity and neuronal adaptation, in vitro and in vivo-from neuronal cells up to neuromuscular responses: a first model.

Science.gov (United States)

Kohn, Florian P M; Ritzmann, Ramona

2018-03-01

For decades it has been shown that acute changes in gravity have an effect on neuronal systems of human and animals on different levels, from the molecular level to the whole nervous system. The functional properties and gravity-dependent adaptations of these system levels have been investigated with no or barely any interconnection. This review summarizes the gravity-dependent adaptation processes in human and animal organisms from the in vitro cellular level with its biophysical properties to the in vivo motor responses and underlying sensorimotor functions of human subjects. Subsequently, a first model for short-term adaptation of neuronal transmission is presented and discussed for the first time, which integrates the responses of the different levels of organization to changes in gravity.

Assessing the effectiveness of climate adaptation

Energy Technology Data Exchange (ETDEWEB)

Anderson, Simon

2011-10-15

As governments and other agencies spend more money on adaptation to climate change they want to know that their investments are effective — that adaptation will keep development on track, that there is a fair distribution of costs and benefits, and that climate resilience is being built. But monitoring and evaluating adaptation policy and practice is not easy. Some approaches are unhelpful because they fail to integrate adaptation and development, use purely quantitative methods and do not include the perspectives of climate-vulnerable groups in their assessments. Enabling countries and organisations to effectively evaluate adaptation requires an inclusive approach built on sharing knowledge among all stakeholders — one that can capture behavioural and institutional changes and that answers to the needs of the climate-vulnerable poor.

Adaptive responses to salinity stress across multiple life stages in anuran amphibians.

Science.gov (United States)

Albecker, Molly A; McCoy, Michael W

2017-01-01

In many regions, freshwater wetlands are increasing in salinity at rates exceeding historic levels. Some freshwater organisms, like amphibians, may be able to adapt and persist in salt-contaminated wetlands by developing salt tolerance. Yet adaptive responses may be more challenging for organisms with complex life histories, because the same environmental stressor can require responses across different ontogenetic stages. Here we investigated responses to salinity in anuran amphibians: a common, freshwater taxon with a complex life cycle. We conducted a meta-analysis to define how the lethality of saltwater exposure changes across multiple life stages, surveyed wetlands in a coastal region experiencing progressive salinization for the presence of anurans, and used common garden experiments to investigate whether chronic salt exposure alters responses in three sequential life stages (reproductive, egg, and tadpole life stages) in Hyla cinerea , a species repeatedly observed in saline wetlands. Meta-analysis revealed differential vulnerability to salt stress across life stages with the egg stage as the most salt-sensitive. Field surveys revealed that 25% of the species known to occur in the focal region were detected in salt-intruded habitats. Remarkably, Hyla cinerea was found in large abundances in multiple wetlands with salinity concentrations 450% higher than the tadpole-stage LC 50 . Common garden experiments showed that coastal (chronically salt exposed) populations of H. cinerea lay more eggs, have higher hatching success, and greater tadpole survival in higher salinities compared to inland (salt naïve) populations. Collectively, our data suggest that some species of anuran amphibians have divergent and adaptive responses to salt exposure across populations and across different life stages. We propose that anuran amphibians may be a novel and amenable natural model system for empirical explorations of adaptive responses to environmental change.

A roadmap to effective urban climate change adaptation

Science.gov (United States)

Setiadi, R.

2018-03-01

This paper outlines a roadmap to effective urban climate change adaptation built from our practical understanding of the evidence and effects of climate change and the preparation of climate change adaptation strategies and plans. This roadmap aims to drive research in achieving fruitful knowledge and solution-based achievable recommendations in adapting to climate change in urban areas with effective and systematic manner. This paper underscores the importance of the interplay between local government initiatives and a national government for effective adaptation to climate change and takes into account the policy process and politics. This paper argues that effective urban climate change adaptation has a contribution to build urban resilience and helps the achievement of national government goals and targets in climate change adaptation.

Adaptive response induced by occupational exposures to ionizing radiation

International Nuclear Information System (INIS)

Barquinero, J.F.; Caballin, M.R.; Barrios, L.; Egozcue, J.; Miro, R.; Ribas, M.

1997-01-01

We have found a significant decreased sensitivity to the cytogenetic effects of both ionizing radiation (IR) (2 Gy of γ rays) and bleomycin (BLM, 0,03 U/ml), in lymphocytes from individuals occupationally exposed to IR when compared with controls. These results suggest that occupational exposures to IR can induce adaptive response that can be detected by a subsequent treatment either by IR or by BLM. When a comparison is made between the cytogenetic effects of both treatments, no correlation was observed at the individual level. On the other hand, the individual frequencies of chromosome aberrations induced by a challenge dose of IR were negatively correlated with the occupationally received doses during the last three years. This correlation was not observed after the challenge treatment of BLM. Moreover, the individual frequencies of chromosome aberrations induced by IR treatment were homogeneous. This is not the case of the individual frequencies of chromatid aberrations induced by BLM, where a great heterogeneity was observed. (authors)

Adaptive responses induced in bone marrow and blood of the rats by tritium contamination

International Nuclear Information System (INIS)

Savu, D.I.; Ionescu, M.A.; Petcu, I.

2000-01-01

It has been more than a decade since the initial report on the phenomenon termed 'adaptive response to ionizing radiation'. Although a number of reports have appeared since then, the understanding of this response is still incomplete. Our group intended to investigate whether the adaptive response could be induced in vivo by low level internal tritium contamination of rats and subsequently exposed to challenging irradiations with fast neutrons or gamma rays. Two experiments were performed and analysed comparatively. In the first experiment the rats have been pre-contaminated for 3 weeks to total doses of 7 cGy and 35 cGy and subsequently irradiated to 1 Gy by fast neutrons (d(13.5)+Be). They were sacrificed after 24 hours. In the second experiment rats were exposed to high gamma irradiation (1.4 Gy) after prior contamination with tritium for 20 days to total doses of 4.4 cGy and 5.1 cGy. We followed up the modifications of two biochemical parameters: (i) the in vitro tritiated thymidine incorporation in the bone marrow cells and (ii) the reduced glutathione level in the blood cells. The thymidine incorporation assay revealed a putative adaptive reaction only for the rats preirradiated with tritiated water to 35 cGy and post-irradiated with fast neutrons. The glutathione content was found to be increased (back to the normal level) for the tritium pre-contaminated and neutron irradiated animals as compared to those exposed only to fast neutrons. The adaptive response is believed to be a protective mechanism that confers resistance to the detrimental effects of ionizing radiation. Our studies suggest that the irradiation with low conditioning doses of tritium (7; 35 cGy) is more efficient in conferring radioresistance to bone marrow and blood cells at the treatment with fast neutrons (1 Gy) than the irradiation with tritium doses of 4.4 and 5.1 cGy followed by gamma rays (1.4 Gy). (authors)

Local adaptation and the potential effects of a contaminant on predator avoidance and antipredator responses under global warming: a space-for-time substitution approach

Science.gov (United States)

Janssens, Lizanne; Dinh Van, Khuong; Debecker, Sara; Bervoets, Lieven; Stoks, Robby

2014-01-01

The ability to deal with temperature-induced changes in interactions with contaminants and predators under global warming is one of the outstanding, applied evolutionary questions. For this, it is crucial to understand how contaminants will affect activity levels, predator avoidance and antipredator responses under global warming and to what extent gradual thermal evolution may mitigate these effects. Using a space-for-time substitution approach, we assessed the potential for gradual thermal evolution shaping activity (mobility and foraging), predator avoidance and antipredator responses when Ischnura elegans damselfly larvae were exposed to zinc in a common-garden warming experiment at the mean summer water temperatures of shallow water bodies at southern and northern latitudes (24 and 20°C, respectively). Zinc reduced mobility and foraging, predator avoidance and escape swimming speed. Importantly, high-latitude populations showed stronger zinc-induced reductions in escape swimming speed at both temperatures, and in activity levels at the high temperature. The latter indicates that local thermal adaptation may strongly change the ecological impact of contaminants under global warming. Our study underscores the critical importance of considering local adaptation along natural gradients when integrating biotic interactions in ecological risk assessment, and the potential of gradual thermal evolution mitigating the effects of warming on the vulnerability to contaminants. PMID:24665344

Local adaptation and the potential effects of a contaminant on predator avoidance and antipredator responses under global warming: a space-for-time substitution approach.

Science.gov (United States)

Janssens, Lizanne; Dinh Van, Khuong; Debecker, Sara; Bervoets, Lieven; Stoks, Robby

2014-03-01

The ability to deal with temperature-induced changes in interactions with contaminants and predators under global warming is one of the outstanding, applied evolutionary questions. For this, it is crucial to understand how contaminants will affect activity levels, predator avoidance and antipredator responses under global warming and to what extent gradual thermal evolution may mitigate these effects. Using a space-for-time substitution approach, we assessed the potential for gradual thermal evolution shaping activity (mobility and foraging), predator avoidance and antipredator responses when Ischnura elegans damselfly larvae were exposed to zinc in a common-garden warming experiment at the mean summer water temperatures of shallow water bodies at southern and northern latitudes (24 and 20°C, respectively). Zinc reduced mobility and foraging, predator avoidance and escape swimming speed. Importantly, high-latitude populations showed stronger zinc-induced reductions in escape swimming speed at both temperatures, and in activity levels at the high temperature. The latter indicates that local thermal adaptation may strongly change the ecological impact of contaminants under global warming. Our study underscores the critical importance of considering local adaptation along natural gradients when integrating biotic interactions in ecological risk assessment, and the potential of gradual thermal evolution mitigating the effects of warming on the vulnerability to contaminants.

Adaptive Response in Animals Exposed to Non-Ionizing Radiofrequency Fields: Some Underlying Mechanisms

Directory of Open Access Journals (Sweden)

Yi Cao

2014-04-01

Full Text Available During the last few years, our research group has been investigating the phenomenon of adaptive response in animals exposed to non-ionizing radiofrequency fields. The results from several separate studies indicated a significant increase in survival, decreases in genetic damage as well as oxidative damage and, alterations in several cellular processes in mice pre-exposed to radiofrequency fields and subsequently subjected to sub-lethal or lethal doses of γ-radiation or injected with bleomycin, a radiomimetic chemical mutagen. These observations indicated the induction of adaptive response providing the animals the ability to resist subsequent damage. Similar studies conducted by independent researchers in mice and rats have supported our observation on increased survival. In this paper, we have presented a brief review of all of our own and other independent investigations on radiofrequency fields-induced adaptive response and some underlying mechanisms discussed.

Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats.

Directory of Open Access Journals (Sweden)

Sarah W Lai

Full Text Available To determine the effects of exogenous glucagon-like peptide-2 (GLP-2, with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats.GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS. However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear.Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB (n = 8, TB + GLP-2 (2.5 nmol/kg/h, n = 8, SBS (n = 5, or SBS + GLP-2 (2.5 nmol/kg/h, n = 9. SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5 and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS, plasma glucose, gut hormones, and body composition.Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2, increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss.Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy of further study.

Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats

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de Heuvel, Elaine; Wallace, Laurie E.; Hartmann, Bolette; Holst, Jens J.; Brindle, Mary E.; Chelikani, Prasanth K.; Sigalet, David L.

2017-01-01

Objective To determine the effects of exogenous glucagon-like peptide-2 (GLP-2), with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats. Background GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS). However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear. Methods Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB) (n = 8), TB + GLP-2 (2.5 nmol/kg/h, n = 8), SBS (n = 5), or SBS + GLP-2 (2.5 nmol/kg/h, n = 9). SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5) and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS), plasma glucose, gut hormones, and body composition. Results Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2), increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss. Conclusions Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy

Public Health and Climate Change Adaptation at the Federal Level: One Agency’s Response to Executive Order 13514

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Schramm, Paul J.; Luber, George

2014-01-01

Climate change will likely have adverse human health effects that require federal agency involvement in adaptation activities. In 2009, President Obama issued Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance. The order required federal agencies to develop and implement climate change adaptation plans. The Centers for Disease Control and Prevention (CDC), as part of a larger Department of Health and Human Services response to climate change, is developing such plans. We provide background on Executive Orders, outline tenets of climate change adaptation, discuss public health adaptation planning at both the Department of Health and Human Services and the CDC, and outline possible future CDC efforts. We also consider how these activities may be better integrated with other adaptation activities that manage emerging health threats posed by climate change. PMID:24432931

Development and Standardization of the Diagnostic Adaptive Behavior Scale: Application of Item Response Theory to the Assessment of Adaptive Behavior

Science.gov (United States)

Tassé, Marc J.; Schalock, Robert L.; Thissen, David; Balboni, Giulia; Bersani, Henry, Jr.; Borthwick-Duffy, Sharon A.; Spreat, Scott; Widaman, Keith F.; Zhang, Dalun; Navas, Patricia

2016-01-01

The Diagnostic Adaptive Behavior Scale (DABS) was developed using item response theory (IRT) methods and was constructed to provide the most precise and valid adaptive behavior information at or near the cutoff point of making a decision regarding a diagnosis of intellectual disability. The DABS initial item pool consisted of 260 items. Using IRT…

Adaptive-impulsive synchronization in drive-response networks of continuous systems and its application

International Nuclear Information System (INIS)

Sun Mei; Zeng Changyan; Tao Yangwei; Tian Lixin

2009-01-01

Based on the comparison theorem for the stability of impulsive control system, adaptive-impulsive synchronization in drive-response networks of continuous systems with time-delay and non-time-delay is investigated. And the continuous control input, the simple updated laws and a linear impulsive controller are proposed. Moreover, two numerical examples are presented to verify the effectiveness and correctness of the theorem, using the energy resource system and Lue's system as the nodes of the networks.

Cross-adaptation between olfactory responses induced by two subgroups of odorant molecules.

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Takeuchi, Hiroko; Imanaka, Yukie; Hirono, Junzo; Kurahashi, Takashi

2003-09-01

It has long been believed that vertebrate olfactory signal transduction is mediated by independent multiple pathways (using cAMP and InsP3 as second messengers). However, the dual presence of parallel pathways in the olfactory receptor cell is still controversial, mainly because of the lack of information regarding the single-cell response induced by odorants that have been shown to produce InsP3 exclusively (but not cAMP) in the olfactory cilia. In this study, we recorded activities of transduction channels of single olfactory receptor cells to InsP3-producing odorants. When the membrane potential was held at -54 mV, application of InsP3-producing odorants to the ciliary region caused an inward current. The reversal potential was 0 +/- 7 mV (mean +/- SD, n = 10). Actually, InsP3-producing odorants generated responses in a smaller fraction of cells (lilial, 3.4%; lyral, 1.7%) than the cAMP-producing odorant (cineole, 26%). But, fundamental properties of responses were surprisingly homologous; namely, spatial distribution of the sensitivity, waveforms, I-V relation, and reversal potential, dose dependence, time integration of stimulus period, adaptation, and recovery. By applying both types of odorants alternatively to the same cell, furthermore, we observed cells to exhibit symmetrical cross-adaptation. It seems likely that even with odorants with different modalities adaptation occurs completely depending on the amount of current flow. The data will also provide evidence showing that olfactory response generation and adaptation are regulated by a uniform mechanism for a wide variety of odorants.

Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change.

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Tomiolo, Sara; Van der Putten, Wim H; Tielbörger, Katja

2015-05-01

Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness. We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species-specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance.

Adaptive governance : Towards a stable, accountable and responsive government

NARCIS (Netherlands)

Janssen, M.F.W.H.A.; van der Voort, H.G.

2016-01-01

Organizations are expected to adapt within a short time to deal with changes that might become disruptive if not adequately dealt with. Yet many organizations are unable to adapt effectively or quickly due to the established institutional arrangements and patterns of decision-making and

Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation.

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Wallentin, Mikkel; Skakkebæk, Anne; Bojesen, Anders; Fedder, Jens; Laurberg, Peter; Østergaard, John R; Hertz, Jens Michael; Pedersen, Anders Degn; Gravholt, Claus Højbjerg

2016-01-01

Klinefelter syndrome (47, XXY) (KS) is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49) responded to whether the words "GREEN" or "RED" were displayed in green or red (incongruent versus congruent colors). One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying "GREEN" or "RED" had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system.

Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation

Directory of Open Access Journals (Sweden)

Mikkel Wallentin

2016-01-01

Full Text Available Klinefelter syndrome (47, XXY (KS is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49 responded to whether the words “GREEN” or “RED” were displayed in green or red (incongruent versus congruent colors. One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying “GREEN” or “RED” had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system.

An adaptive two-stage dose-response design method for establishing proof of concept.

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Franchetti, Yoko; Anderson, Stewart J; Sampson, Allan R

2013-01-01

We propose an adaptive two-stage dose-response design where a prespecified adaptation rule is used to add and/or drop treatment arms between the stages. We extend the multiple comparison procedures-modeling (MCP-Mod) approach into a two-stage design. In each stage, we use the same set of candidate dose-response models and test for a dose-response relationship or proof of concept (PoC) via model-associated statistics. The stage-wise test results are then combined to establish "global" PoC using a conditional error function. Our simulation studies showed good and more robust power in our design method compared to conventional and fixed designs.

Detection of plant adaptation responses to saline environment in rhizosphere using microwave sensing

International Nuclear Information System (INIS)

Shimomachi, T.; Kobashikawa, C.; Tanigawa, H.; Omoda, E.

2008-01-01

The physiological adaptation responses in plants to environmental stress, such as water stress and salt stress induce changes in physicochemical conditions of the plant, since formation of osmotic-regulatory substances can be formed during the environmental adaptation responses. Strong electrolytes, amino acids, proteins and saccharides are well-known as osmoregulatory substances. Since these substances are ionic conductors and their molecules are electrically dipolar, it can be considered that these substances cause changes in the dielectric properties of the plant, which can be detected by microwave sensing. The dielectric properties (0.3 to 3GHz), water content and water potential of plant leaves which reflect the physiological condition of the plant under salt stress were measured and analyzed. Experimental results showed the potential of the microwave sensing as a method for monitoring adaptation responses in plants under saline environment and that suggested the saline environment in rhizosphere can be detected noninvasively and quantitatively by the microwave sensing which detects the changes in complex dielectric properties of the plant

Strategic Adaptation

DEFF Research Database (Denmark)

Andersen, Torben Juul

2015-01-01

This article provides an overview of theoretical contributions that have influenced the discourse around strategic adaptation including contingency perspectives, strategic fit reasoning, decision structure, information processing, corporate entrepreneurship, and strategy process. The related...... concepts of strategic renewal, dynamic managerial capabilities, dynamic capabilities, and strategic response capabilities are discussed and contextualized against strategic responsiveness. The insights derived from this article are used to outline the contours of a dynamic process of strategic adaptation....... This model incorporates elements of central strategizing, autonomous entrepreneurial behavior, interactive information processing, and open communication systems that enhance the organization's ability to observe exogenous changes and respond effectively to them....

Using response-time constraints in item selection to control for differential speededness in computerized adaptive testing

NARCIS (Netherlands)

van der Linden, Willem J.; Scrams, David J.; Schnipke, Deborah L.

2003-01-01

This paper proposes an item selection algorithm that can be used to neutralize the effect of time limits in computer adaptive testing. The method is based on a statistical model for the response-time distributions of the test takers on the items in the pool that is updated each time a new item has

Adaptive and cross-protective responses against cadmium and zinc toxicity in cadmium-resistant bacterium isolated from a zinc mine

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Benjaphorn Prapagdee

2009-12-01

Full Text Available Cadmium (Cd is a major environmental hazard, which usually is detected in its ionic form of Cd2+. It also causes adverse toxic effects on human health and other living organisms. Cd-resistant bacteria were isolated from Cd-contaminated soils. One isolate, TAK1, was highly resistance level to Cd toxicity. TAK1 was isolated from soil contaminated with a high Cd concentration (204.1 mg.kg-1. The result of 16S rDNA sequence analysis found that the TAK1 showed the similarity to Ralstonia sp. Physiological adaptive and cross-protective responses to Cd and Zn killing were investigated in Ralstonia sp.TAK1. Exposure to a low concentration of Cd induced adaptive resistance to higher concentrations of Cd. In addition, pretreatment of Ralstonia sp.TAK1 with an inducing concentration of Cd conferred cross-protective response against subsequent exposure to the lethal concentrations of Zn. The induced adaptive and cross-protective response Ralstonia sp.TAK1 required newly synthesized protein(s. Cd-induced adaptive and cross-protective responses against Cd and Zn toxicity are the important mechanisms used by Ralstonia sp.TAK1 to survive in the heavy metal contaminated environments. These findings might lead to the use of Ralstonia sp.TAK1 for microbial based remediation in Cd and Zn-contaminated soils.

A composite microdose Adaptive Response (AR) and Bystander Effect (BE) model-application to low LET and high LET AR and BE data.

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Leonard, Bobby E

2008-08-01

It has been suggested that Adaptive Response (AR) may reduce risk of adverse health effects due to ionizing radiation. But very low dose Bystander Effects (BE) may impose dominant deleterious human risks. These conflicting behaviors have stimulated controversy regarding the Linear No-Threshold human risk model. A dose and dose rate-dependent microdose model, to examine AR behavior, was developed in prior work. In the prior work a number of in vitro and in vivo dose response data were examined with the model. Recent new data show AR behavior with some evidence of very low dose BE. The purpose of this work is to supplement the microdose model to encompass the Brenner and colleagues BaD (Bystander and Direct Damage) model and apply this composite model to obtain new knowledge regarding AR and BE and illustrate the use of the model to plan radio-biology experiments. The biophysical composite AR and BE Microdose Model quantifies the accumulation of hits (Poisson distributed, microdose specific energy depositions) to cell nucleus volumes. This new composite AR and BE model provides predictions of dose response at very low dose BE levels, higher dose AR levels and even higher dose Direct (linear-quadratic) Damage radiation levels. We find good fits of the model to both BE data from the Columbia University microbeam facility and combined AR and BE data for low Linear Energy Transfer (LET) and high LET data. A Bystander Factor of about 27,000 and an AR protection factor of 0.61 are obtained for the low LET in vivo mouse spleen exposures. A Bystander Factor of 317 and an AR protection factor of 0.53 are obtained for high LET radon alpha particles in human lymphocytes. In both cases the AR is activated at most by one or two radiation induced charged particle traversals through the cell nucleus. The results of the model analysis is consistent with a premise that both Bystander damage and Adaptive Response radioprotection can occur in the same cell type, derived from the same

Adaptive Governance, Uncertainty, and Risk: Policy Framing and Responses to Climate Change, Drought, and Flood.

Science.gov (United States)

Hurlbert, Margot; Gupta, Joyeeta

2016-02-01

As climate change impacts result in more extreme events (such as droughts and floods), the need to understand which policies facilitate effective climate change adaptation becomes crucial. Hence, this article answers the question: How do governments and policymakers frame policy in relation to climate change, droughts, and floods and what governance structures facilitate adaptation? This research interrogates and analyzes through content analysis, supplemented by semi-structured qualitative interviews, the policy response to climate change, drought, and flood in relation to agricultural producers in four case studies in river basins in Chile, Argentina, and Canada. First, an epistemological explanation of risk and uncertainty underscores a brief literature review of adaptive governance, followed by policy framing in relation to risk and uncertainty, and an analytical model is developed. Pertinent findings of the four cases are recounted, followed by a comparative analysis. In conclusion, recommendations are made to improve policies and expand adaptive governance to better account for uncertainty and risk. This article is innovative in that it proposes an expanded model of adaptive governance in relation to "risk" that can help bridge the barrier of uncertainty in science and policy. © 2015 Society for Risk Analysis.

Human adaptation responses to a rapidly changing Arctic: A research context for building system resilience

Science.gov (United States)

Chapin, T.; Brinkman, T. J.

2016-12-01

Although human behavior accounts for more uncertainty in future trajectories in climate change than do biophysical processes, most climate-change research fails to include human actions in research design and implementation. This is well-illustrated in the Arctic. At the global scale, arctic processes strongly influence the strength of biophysical feedbacks between global human emissions and the rate of climate warming. However, most human actions in the arctic have little effect on these feedbacks, so research can contribute most effectively to reduction in arctic warming through improved understanding of the strength of arctic-global biophysical feedbacks, as in NASA's ABoVE program, and its effective communication to policy makers and the public. In contrast, at the local to regional scale within the arctic, human actions may influence the ecological and societal consequences of arctic warming, so research benefits from active stakeholder engagement in research design and implementation. Human communities and other stakeholders (government and NGOs) respond heterogeneously to socioeconomic and environmental change, so research that documents the range of historical and current adaptive responses to change provides insights on the resilience (flexibility of future options) of social-ecological processes in the arctic. Alaskan communities have attempted a range of adaptive responses to coastal erosion (e.g., seasonal migration, protection in place, relocation), wildfire (fire suppression to use of fire to manage wildlife habitat or landscape heterogeneity), declining sea ice (e.g., new hunting technology, sea ice observations and predictions), and changes in wildlife and fish availability (e.g., switch to harvest of alternative species, harvest times, or harvest locations). Research that draws on both traditional and western knowledge facilitates adaptation and predictions of the likely societal consequences of climate change in the Arctic. Effective inclusion of

Effects of ageing on adaptation during vibratory stimulation of the calf and neck muscles.

Science.gov (United States)

Patel, M; Fransson, P A; Magnusson, M

2009-01-01

The ability to adapt and habituate based on prior experiences is important for human movement control, fall prevention and for the ability to enhance performance during various human activities. However, little is known about the ability for the elderly to adapt to balance perturbations in the lateral direction. To determine whether adaptation, i.e., the ability to adjust postural control to handle balance perturbations better over time, differed in the elderly subjects compared with young subjects in the anteroposterior and lateral directions, and whether the site of the balance perturbation or the presence or absence of vision affected the response. Postural stability was measured as anteroposterior and lateral torque variance in a young group (n = 18 (9 female and 9 male), average age = 29.1 years) and an elderly group (n = 16 (5 female and 11 male), average age = 71.5 years) with eyes open and closed during balance perturbations from calf and neck vibrations. After a 30-s period of quiet stance, these vibrations were repeated over a period of 200 s, so the adaptive responses could be analyzed by splitting the data into 50-s periods. The adaptive responses in the anteroposterior and lateral directions were different. Adaptation in the anteroposterior direction occurred to an almost equal extent in the elderly and young, whereas adaptation in the lateral direction was markedly larger in the elderly in all tests except for neck vibration with eyes closed. Age, vision and vibration site were all influential factors for recorded body movements, but no significant combined effects were found. Balance perturbation instigates an adaptive response in the elderly in both the anteroposterior and lateral directions. However, during perturbation, age and vision are both very influential factors for the stability, thus associating the previously documented age-related decline in visual functioning with a higher risk of falls in this age range. (c) 2008 S. Karger AG, Basel.

Innate scavenger receptor-A regulates adaptive T helper cell responses to pathogen infection

Science.gov (United States)

Xu, Zhipeng; Xu, Lei; Li, Wei; Jin, Xin; Song, Xian; Chen, Xiaojun; Zhu, Jifeng; Zhou, Sha; Li, Yong; Zhang, Weiwei; Dong, Xiaoxiao; Yang, Xiaowei; Liu, Feng; Bai, Hui; Chen, Qi; Su, Chuan

2017-01-01

The pattern recognition receptor (PRR) scavenger receptor class A (SR-A) has an important function in the pathogenesis of non-infectious diseases and in innate immune responses to pathogen infections. However, little is known about the role of SR-A in the host adaptive immune responses to pathogen infection. Here we show with mouse models of helminth Schistosoma japonicum infection and heat-inactivated Mycobacterium tuberculosis stimulation that SR-A is regulated by pathogens and suppresses IRF5 nuclear translocation by direct interaction. Reduced abundance of nuclear IRF5 shifts macrophage polarization from M1 towards M2, which subsequently switches T-helper responses from type 1 to type 2. Our study identifies a role for SR-A as an innate PRR in regulating adaptive immune responses. PMID:28695899

Genetic dissection of the Arabidopsis spaceflight transcriptome: Are some responses dispensable for the physiological adaptation of plants to spaceflight?

Directory of Open Access Journals (Sweden)

Anna-Lisa Paul

Full Text Available Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response

Reducing barriers to healthy weight: Planned and responsive adaptations to a lifestyle intervention to serve people with impaired mobility.

Science.gov (United States)

Betts, Andrea C; Froehlich-Grobe, Katherine; Driver, Simon; Carlton, Danielle; Kramer, M Kaye

2018-04-01

People with impaired mobility (IM) disabilities have a higher prevalence of obesity and obesity-related chronic conditions; however, lifestyle interventions that address the unique needs of people with IM are lacking. This paper describes an adapted evidence-based lifestyle intervention developed through community-based participatory research (CBPR). Individuals with IM, health professionals, disability group representatives, and researchers formed an advisory board to guide the process of thoroughly adapting the Diabetes Prevention Program Group Lifestyle Balance (DPP GLB) intervention after a successful pilot in people with IM. The process involved two phases: 1) planned adaptations to DPP GLB content and delivery, and 2) responsive adaptations to address issues that emerged during intervention delivery. Planned adaptations included combining in-person sessions with conference calls, providing arm-based activity trackers, and adding content on adaptive cooking, adaptive physical activity, injury prevention, unique health considerations, self-advocacy, and caregiver support. During the intervention, participants encountered numerous barriers, including health and mental health issues, transportation, caregivers, employment, adjusting to disability, and functional limitations. We addressed barriers with responsive adaptations, such as supporting electronic self-monitoring, offering make up sessions, and adding content and activities on goal setting, problem solving, planning, peer support, reflection, and motivation. Given the lack of evidence on lifestyle change in people with disabilities, it is critical to involve the community in intervention planning and respond to real-time barriers as participants engage in change. A randomized controlled trial (RCT) is underway to examine the usability, feasibility, and preliminary effectiveness of the adapted intervention. Copyright © 2017 Elsevier Inc. All rights reserved.

Household Adaptive Behavior in Response to Coastal Flood Risk and External Stressors

Science.gov (United States)

Buchanan, M. K.

2017-12-01

Approximately forty percent of the world's population sits along ocean coastlines. This urban exposure to flooding is increasing due to population growth and sea level rise resulting from anthropogenic climate change. Recent research improving the characterization of physical hazards from climate change on the coastal zone has helped cities assess their risks. This work includes improving our understanding of the rate and magnitude of sea level rise, the change in distribution of tropical cyclones, and the resulting frequency and severity of flooding on global to local scales. However, the ability of settlements to cope or thrive under changing climate conditions will likely depend on the cooperation and initiative of households, regardless of any governmental efforts to reduce risk. Understanding individuals' likely responses to changing coastal hazards is thus critical for decision-makers to plan for a sustainable future. Individuals may be motivated not only by information regarding emerging flood hazards, but also by cognitive and contextual factors. For governments to develop effective adaptation policies, it is important to understand what factors tend to motivate household adaptation. We apply principles from economics and psychology to investigate how people respond to various existing adaptation options and policies, using a household survey with experiments in New York City neighborhoods affected by Hurricane Sandy. We investigate a comprehensive set of factors that may influence household adaptive behavior. A striking 64% of homeowners and 83% of renters intend to relocate among different plausible future conditions, such as frequent nuisance flooding and the adaptation of peers. This amount is substantial considering the political sensitivity of `retreat' and the lack of regional and federal preparation for large-scale climate-induced migration.

Prediction of adaptive self-regulatory responses to arthritis pain anxiety in exercising adults: does pain acceptance matter?

Science.gov (United States)

Cary, Miranda Ashley; Gyurcsik, Nancy C; Brawley, Lawrence R

2015-01-01

Exercising for ≥ 150 min/week is a recommended strategy for self-managing arthritis. However, exercise nonadherence is a problem. Arthritis pain anxiety may interfere with regular exercise. According to the fear-avoidance model, individuals may confront their pain anxiety by using adaptive self-regulatory responses (eg, changing exercise type or duration). Furthermore, the anxiety-self-regulatory responses relationship may vary as a function of individuals' pain acceptance levels. To investigate pain acceptance as a moderator of the pain anxiety-adaptive self-regulatory responses relationship. The secondary objective was to examine whether groups of patients who differed in meeting exercise recommendations also differed in pain-related and self-regulatory responses. Adults (mean [± SD] age 49.75 ± 13.88 years) with medically diagnosed arthritis completed online measures of arthritis pain-related variables and self-regulatory responses at baseline, and exercise participation two weeks later. Individuals meeting (n=87) and not meeting (n=49) exercise recommendations were identified. Hierarchical multiple regression analysis revealed that pain acceptance moderated the anxiety-adaptive self-regulatory responses relationship. When pain anxiety was lower, greater pain acceptance was associated with less frequent use of adaptive responses. When anxiety was higher, adaptive responses were used regardless of pain acceptance level. MANOVA findings revealed that participants meeting the recommended exercise dose reported significantly lower pain and pain anxiety, and greater pain acceptance (Pself-regulatory capacity to cope with additional challenges to exercise adherence (eg, busy schedule).

Effect of prism adaptation on left dichotic listening deficit in neglect patients: glasses to hear better?

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Jacquin-Courtois, S; Rode, G; Pavani, F; O'Shea, J; Giard, M H; Boisson, D; Rossetti, Y

2010-03-01

Unilateral neglect is a disabling syndrome frequently observed following right hemisphere brain damage. Symptoms range from visuo-motor impairments through to deficient visuo-spatial imagery, but impairment can also affect the auditory modality. A short period of adaptation to a rightward prismatic shift of the visual field is known to improve a wide range of hemispatial neglect symptoms, including visuo-manual tasks, mental imagery, postural imbalance, visuo-verbal measures and number bisection. The aim of the present study was to assess whether the beneficial effects of prism adaptation may generalize to auditory manifestations of neglect. Auditory extinction, whose clinical manifestations are independent of the sensory modalities engaged in visuo-manual adaptation, was examined in neglect patients before and after prism adaptation. Two separate groups of neglect patients (all of whom exhibited left auditory extinction) underwent prism adaptation: one group (n = 6) received a classical prism treatment ('Prism' group), the other group (n = 6) was submitted to the same procedure, but wore neutral glasses creating no optical shift (placebo 'Control' group). Auditory extinction was assessed by means of a dichotic listening task performed three times: prior to prism exposure (pre-test), upon prism removal (0 h post-test) and 2 h later (2 h post-test). The total number of correct responses, the lateralization index (detection asymmetry between the two ears) and the number of left-right fusion errors were analysed. Our results demonstrate that prism adaptation can improve left auditory extinction, thus revealing transfer of benefit to a sensory modality that is orthogonal to the visual, proprioceptive and motor modalities directly implicated in the visuo-motor adaptive process. The observed benefit was specific to the detection asymmetry between the two ears and did not affect the total number of responses. This indicates a specific effect of prism adaptation on

Population variability in biological adaptive responses to DNA damage and the shapes of carcinogen dose-response curves

International Nuclear Information System (INIS)

Conolly, Rory B.; Gaylor, David W.; Lutz, Werner K.

2005-01-01

Carcinogen dose-response curves for both ionizing radiation and chemicals are typically assumed to be linear at environmentally relevant doses. This assumption is used to ensure protection of the public health in the absence of relevant dose-response data. A theoretical justification for the assumption has been provided by the argument that low dose linearity is expected when an exogenous agent adds to an ongoing endogenous process. Here, we use computational modeling to evaluate (1) how two biological adaptive processes, induction of DNA repair and cell cycle checkpoint control, may affect the shapes of dose-response curves for DNA-damaging carcinogens and (2) how the resulting dose-response behaviors may vary within a population. Each model incorporating an adaptive process was capable of generating not only monotonic dose-responses but also nonmonotonic (J-shaped) and threshold responses. Monte Carlo analysis suggested that all these dose-response behaviors could coexist within a population, as the spectrum of qualitative differences arose from quantitative changes in parameter values. While this analysis is largely theoretical, it suggests that (a) accurate prediction of the qualitative form of the dose-response requires a quantitative understanding of the mechanism (b) significant uncertainty is associated with human health risk prediction in the absence of such quantitative understanding and (c) a stronger experimental and regulatory focus on biological mechanisms and interindividual variability would allow flexibility in regulatory treatment of environmental carcinogens without compromising human health

Separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation.

Science.gov (United States)

Bailey, Kira; Amlung, Michael T; Morris, David H; Price, Mason H; Von Gunten, Curtis; McCarthy, Denis M; Bartholow, Bruce D

2016-04-01

Caffeine is commonly believed to offset the acute effects of alcohol, but some evidence suggests that cognitive processes remain impaired when caffeine and alcohol are coadministered. No previous study has investigated the separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation, processes thought to be critical for self-regulation. This was the purpose of the current study. Healthy, young adult social drinkers recruited from the community completed a flanker task after consuming one of four beverages in a 2 × 2 experimental design: Alcohol + caffeine, alcohol + placebo caffeine, placebo alcohol + caffeine, or placebo alcohol + placebo caffeine. Accuracy, response time, and the amplitude of the N2 component of the event-related potential (ERP), a neural index of conflict monitoring, were examined as a function of whether or not conflict was present (i.e., whether or not flankers were compatible with the target) on both the previous trial and the current trial. Alcohol did not abolish conflict monitoring or adaptation. Caffeine eliminated conflict adaptation in sequential trials but also enhanced neural conflict monitoring. The combined effect of alcohol and caffeine was apparent only in how previous conflict affected the neural conflict monitoring response. Together, the findings suggest that caffeine leads to exaggeration of attentional resource utilization, which could provide short-term benefits but lead to problems conserving resources for when they are most needed.

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

Science.gov (United States)

Chatzitomaris, Apostolos; Hoermann, Rudolf; Midgley, John E.; Hering, Steffen; Urban, Aline; Dietrich, Barbara; Abood, Assjana; Klein, Harald H.; Dietrich, Johannes W.

2017-01-01

The hypothalamus–pituitary–thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTIS) or thyroid allostasis in critical illness, tumors, uremia, and starvation (TACITUS), commonly observed in hospitalized patients, displays a historically well-studied pattern of allostatic thyroid response. This is characterized by decreased total and free thyroid hormone concentrations and varying levels of thyroid-stimulating hormone (TSH) ranging from decreased (in severe cases) to normal or even elevated (mainly in the recovery phase) TSH concentrations. An acute versus chronic stage (wasting syndrome) of TACITUS can be discerned. The two types differ in molecular mechanisms and prognosis. The acute adaptation of thyroid hormone metabolism to critical illness may prove beneficial to the organism, whereas the far more complex molecular alterations associated with chronic illness frequently lead to allostatic overload. The latter is associated with poor outcome, independently of the underlying disease. Adaptive responses of thyroid homeostasis extend to alterations in thyroid hormone concentrations during fetal life, periods of weight gain or loss, thermoregulation, physical exercise, and psychiatric diseases. The various forms of thyroid allostasis pose serious problems in differential diagnosis of thyroid disease. This review article provides an overview of physiological mechanisms as well as major diagnostic and therapeutic implications of thyroid allostasis under a variety of developmental and straining conditions. PMID:28775711

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

Directory of Open Access Journals (Sweden)

Apostolos Chatzitomaris

2017-07-01

Full Text Available The hypothalamus–pituitary–thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTIS or thyroid allostasis in critical illness, tumors, uremia, and starvation (TACITUS, commonly observed in hospitalized patients, displays a historically well-studied pattern of allostatic thyroid response. This is characterized by decreased total and free thyroid hormone concentrations and varying levels of thyroid-stimulating hormone (TSH ranging from decreased (in severe cases to normal or even elevated (mainly in the recovery phase TSH concentrations. An acute versus chronic stage (wasting syndrome of TACITUS can be discerned. The two types differ in molecular mechanisms and prognosis. The acute adaptation of thyroid hormone metabolism to critical illness may prove beneficial to the organism, whereas the far more complex molecular alterations associated with chronic illness frequently lead to allostatic overload. The latter is associated with poor outcome, independently of the underlying disease. Adaptive responses of thyroid homeostasis extend to alterations in thyroid hormone concentrations during fetal life, periods of weight gain or loss, thermoregulation, physical exercise, and psychiatric diseases. The various forms of thyroid allostasis pose serious problems in differential diagnosis of thyroid disease. This review article provides an overview of physiological mechanisms as well as major diagnostic and therapeutic implications of thyroid allostasis under a variety of developmental and straining conditions.

The health policy implications of individual adaptive behavior responses to smog pollution in urban China.

Science.gov (United States)

Ban, Jie; Zhou, Lian; Zhang, Yi; Brooke Anderson, G; Li, Tiantian

2017-09-01

Smog pollution is a serious public health issue in urban China, where it is associated with public health through a range of respiratory and cardiovascular illnesses. Despite the negative health impacts of smog pollution, individual adaptive behaviors are poorly understood. This knowledge gap hinders the development of effective public policy to support and encourage the adoption of individual adaptive and mitigating behaviors to smog pollution. A questionnaire survey of 1141 randomly sampled individuals in a typical PM 2.5 -polluted Chinese city was designed to establish smog concerns and behavior changes during smog events. The results demonstrate a variety of behavior responses associated with risk perception, experience of smog, age, and gender of respondents. An understanding of these variations is critical to the development of effective public policy and ultimately to the improvement of public health in cities affected by smog. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oxidative stress and inflammation: liver responses and adaptations to acute and regular exercise.

Science.gov (United States)

Pillon Barcelos, Rômulo; Freire Royes, Luiz Fernando; Gonzalez-Gallego, Javier; Bresciani, Guilherme

2017-02-01

The liver is remarkably important during exercise outcomes due to its contribution to detoxification, synthesis, and release of biomolecules, and energy supply to the exercising muscles. Recently, liver has been also shown to play an important role in redox status and inflammatory modulation during exercise. However, while several studies have described the adaptations of skeletal muscles to acute and chronic exercise, hepatic changes are still scarcely investigated. Indeed, acute intense exercise challenges the liver with increased reactive oxygen species (ROS) and inflammation onset, whereas regular training induces hepatic antioxidant and anti-inflammatory improvements. Acute and regular exercise protocols in combination with antioxidant and anti-inflammatory supplementation have been also tested to verify hepatic adaptations to exercise. Although positive results have been reported in some acute models, several studies have shown an increased exercise-related stress upon liver. A similar trend has been observed during training: while synergistic effects of training and antioxidant/anti-inflammatory supplementations have been occasionally found, others reported a blunting of relevant adaptations to exercise, following the patterns described in skeletal muscles. This review discusses current data regarding liver responses and adaptation to acute and regular exercise protocols alone or combined with antioxidant and anti-inflammatory supplementation. The understanding of the mechanisms behind these modulations is of interest for both exercise-related health and performance outcomes.

Characteristic of immunological adaptive response induced by low level whole body irradiation with X-rays in mice

International Nuclear Information System (INIS)

Ju Guizhi; Song Chunhua; Qi Jin; Liu Shuzheng

1995-01-01

The range of preirradiated doses (D 1 ) and challenge doses (D 2 ) for the induction of immunological adaptive response and the optimum time intervals between D 1 and D 2 were investigated in Kunming mice. The results were as follows: 1. Single whole body preirradiation by X-rays with D 1 doses of 25∼100 mGy (12.5 mGy/min) could induce adaptive response of spontaneous incorporation of 3 H-TdR into thymocytes and the reaction of splenocytes to LPS. 2. With D 2 doses of 1.0 to 1.5 Gy, the adaptive response of spontaneous incorporation of 3 H-TdR into thymocytes and the reaction of splenocytes to ConA and LPS could be induced. 3. The optimum interval for the induction of immunological adaptive response between D 1 and D 2 could be 6∼12 h

Participation of intercellular communication and intracellular signal transduction in the radio-adaptive response of human fibroblastic cells

International Nuclear Information System (INIS)

Ishii, Keiichiro; Hoshi, Yuko; Iwasaki, Toshiyasu; Watanabe, Masami

1997-01-01

To investigate the radio-adaptive response of normal cells to low-dose radiation, we irradiated human embryonic cells with low-dose X-rays and examined the changes in sensitivity to subsequent high-dose X-irradiation. When the cells were irradiated by 200 cGy, the growth ratio of the viable cells five days after the irradiation decreased to 37% of that of the cells which received no X-irradiation. When the cells received a conditioning irradiation of 10 to 20 cGy four hours before the irradiation of 200 cGy, the growth ratio increased significantly to 45-53%, and a peak was reached at a conditioning dose of 13 cGy. Cells blocked off intercellular communication either in Ca 2+ ion-free medium or in TPA added medium during the conditioning irradiation of 13 cGy did not show the improvement of growth ratio. Addition of H-7, as an inhibitor of PKC, to the medium during the conditioning irradiation inhibited the induction of the radio-adaptive response. However, addition of either inhibitor of A kinase, H-89, or inhibitor of G kinase, H-8, failed to inhibit the induction of the radio-adaptive response. These results suggest that: (1) normal cells show an adaptive response to low-dose radiation, (2) intercellular communication may play a role in radio-adaptive responses, (3) the transduction of the signal induced in cells by low-dose X-irradiation via protein kinase C was involved in radio-adaptive responses, not via A kinase nor G kinase. (author)

Opposite Effects of Stress on Pain Modulation Depend on the Magnitude of Individual Stress Response.

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Geva, Nirit; Defrin, Ruth

2018-04-01

The effect of acute stress on pain threshold and intolerance threshold are reported as producing either hypoalgesia or hyperalgesia. Yet, the contribution of individual stress reactivity in this respect has not been established. The aim was to test 2 pain modulation paradigms under acute stress manipulation, to our knowledge, for the first time, to study whether stress differentially affects pain modulation, and whether the effect is related to individual stress response. Participants were 31 healthy subjects. Conditioned pain modulation (CPM) and pain adaptation were measured before and after inducing an acute stress response using the Montreal Imaging Stress Task. Subjects' stress response was evaluated according to salivary cortisol, autonomic function, and perceived stress and anxiety. The Montreal Imaging Stress Task induced a validated stress response. On a group level, stress induced reduction in CPM magnitude and increase in pain adaptation compared with baseline. These responses correlated with stress reactivity. When the group was subdivided according to stress reactivity, only high stress responders exhibited reduced CPM whereas only low stress responders exhibited increased pain adaptation. The results suggest that acute stress may induce opposite effects on pain modulation, depending on individual stress reactivity magnitude, with an advantage to low stress responders. This study evaluated the effect of acute stress on pain modulation. Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders. Identification of high stress responders may promote better pain management. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

The specificity of neural responses to music and their relation to voice processing: an fMRI-adaptation study.

Science.gov (United States)

Armony, Jorge L; Aubé, William; Angulo-Perkins, Arafat; Peretz, Isabelle; Concha, Luis

2015-04-23

Several studies have identified, using functional magnetic resonance imaging (fMRI), a region within the superior temporal gyrus that preferentially responds to musical stimuli. However, in most cases, significant responses to other complex stimuli, particularly human voice, were also observed. Thus, it remains unknown if the same neurons respond to both stimulus types, albeit with different strengths, or whether the responses observed with fMRI are generated by distinct, overlapping neural populations. To address this question, we conducted an fMRI experiment in which short music excerpts and human vocalizations were presented in a pseudo-random order. Critically, we performed an adaptation-based analysis in which responses to the stimuli were analyzed taking into account the category of the preceding stimulus. Our results confirm the presence of a region in the anterior STG that responds more strongly to music than voice. Moreover, we found a music-specific adaptation effect in this area, consistent with the existence of music-preferred neurons. Lack of differences between musicians and non-musicians argues against an expertise effect. These findings provide further support for neural separability between music and speech within the temporal lobe. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

RARtool: A MATLAB Software Package for Designing Response-Adaptive Randomized Clinical Trials with Time-to-Event Outcomes.

Science.gov (United States)

Ryeznik, Yevgen; Sverdlov, Oleksandr; Wong, Weng Kee

2015-08-01

Response-adaptive randomization designs are becoming increasingly popular in clinical trial practice. In this paper, we present RARtool , a user interface software developed in MATLAB for designing response-adaptive randomized comparative clinical trials with censored time-to-event outcomes. The RARtool software can compute different types of optimal treatment allocation designs, and it can simulate response-adaptive randomization procedures targeting selected optimal allocations. Through simulations, an investigator can assess design characteristics under a variety of experimental scenarios and select the best procedure for practical implementation. We illustrate the utility of our RARtool software by redesigning a survival trial from the literature.

Kinetics of the early adaptive response and adaptation threshold dose; Cinetica de la respuesta adaptativa temprana y dosis umbral de adaptacion

Energy Technology Data Exchange (ETDEWEB)

Mendiola C, M.T.; Morales R, P. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2003-07-01

The expression kinetics of the adaptive response (RA) in mouse leukocytes in vivo and the minimum dose of gamma radiation that induces it was determined. The mice were exposed 0.005 or 0.02 Gy of {sup 137} Cs like adaptation and 1h later to the challenge dose (1.0 Gy), another group was only exposed at 1.0 Gy and the damage is evaluated in the DNA with the rehearsal it makes. The treatment with 0. 005 Gy didn't induce RA and 0. 02 Gy causes a similar effect to the one obtained with 0.01 Gy. The RA was show from an interval of 0.5 h being obtained the maximum expression with 5.0 h. The threshold dose to induce the RA is 0.01 Gy and in 5.0 h the biggest quantity in molecules is presented presumably that are related with the protection of the DNA. (Author) =.

No evidence of local adaptation of immune responses to Gyrodactylus in three-spined stickleback (Gasterosteus aculeatus).

Science.gov (United States)

Robertson, Shaun; Bradley, Janette E; MacColl, Andrew D C

2017-01-01

Parasitism represents one of the most widespread lifestyles in the animal kingdom, with the potential to drive coevolutionary dynamics with their host population. Where hosts and parasites evolve together, we may find local adaptation. As one of the main host defences against infection, there is the potential for the immune response to be adapted to local parasites. In this study, we used the three-spined stickleback and its Gyrodactylus parasites to examine the extent of local adaptation of parasite infection dynamics and the immune response to infection. We took two geographically isolated host populations infected with two distinct Gyrodactylus species and performed a reciprocal cross-infection experiment in controlled laboratory conditions. Parasite burdens were monitored over the course of the infection, and individuals were sampled at multiple time points for immune gene expression analysis. We found large differences in virulence between parasite species, irrespective of host, and maladaptation of parasites to their sympatric host. The immune system responded to infection, with a decrease in expression of innate and Th1-type adaptive response genes in fish infected with the less virulent parasite, representing a marker of a possible resistance mechanism. There was no evidence of local adaptation in immune gene expression levels. Our results add to the growing understanding of the extent of host-parasite local adaptation, and demonstrate a systemic immune response during infection with a common ectoparasite. Further immunological studies using the stickleback-Gyrodactylus system can continue to contribute to our understanding of the function of the immune response in natural populations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Predicting adaptation to parenthood: The role of responsiveness, gratitude, and trust

NARCIS (Netherlands)

Kuile, H. ter; Kluwer, E.S.; Finkenauer, C.; Lippe, A.G. van der

2017-01-01

The influence of positive relationship processes, specifically perceived responsiveness, felt gratitude, and felt trust, on perceived adaptation to parenthood was investigated. It was hypothesized that both higher initial levels prior to pregnancy as well as increases over time in perceived

Dual function of CD70 in viral infection: modulator of early cytokine responses and activator of adaptive responses1

Science.gov (United States)

Allam, Atef; Swiecki, Melissa; Vermi, William; Ashwell, Jonathan D.; Colonna, Marco

2014-01-01

The role of the tumor necrosis factor family member CD70 in adaptive T cell responses has been intensively studied but its function in innate responses is still under investigation. Here we show that CD70 inhibits the early innate response to murine cytomegalovirus (MCMV) but is essential for the optimal generation of virus-specific CD8 T cells. CD70-/- mice reacted to MCMV infection with a robust type I interferon and proinflammatory cytokine response. This response was sufficient for initial control of MCMV, although at later time points, CD70-/- mice became more susceptible to MCMV infection. The heightened cytokine response during the early phase of MCMV infection in CD70-/- mice was paralleled by a reduction in regulatory T cells (Treg). Treg from naïve CD70-/- mice were not as efficient at suppressing T cell proliferation compared to Treg from naïve WT mice and depletion of Treg during MCMV infection in Foxp3-DTR mice or in WT mice recapitulated the phenotype observed in CD70-/- mice. Our study demonstrates that while CD70 is required for the activation of the antiviral adaptive response, it has a regulatory role in early cytokine responses to viruses such as MCMV, possibly through maintenance of Treg survival and function. PMID:24913981

Local adaptation in transgenerational responses to predators

Science.gov (United States)

Walsh, Matthew R.; Castoe, Todd; Holmes, Julian; Packer, Michelle; Biles, Kelsey; Walsh, Melissa; Munch, Stephan B.; Post, David M.

2016-01-01

Environmental signals can induce phenotypic changes that span multiple generations. Along with phenotypic responses that occur during development (i.e. ‘within-generation’ plasticity), such ‘transgenerational plasticity’ (TGP) has been documented in a diverse array of taxa spanning many environmental perturbations. New theory predicts that temporal stability is a key driver of the evolution of TGP. We tested this prediction using natural populations of zooplankton from lakes in Connecticut that span a large gradient in the temporal dynamics of predator-induced mortality. We reared more than 120 clones of Daphnia ambigua from nine lakes for multiple generations in the presence/absence of predator cues. We found that temporal variation in mortality selects for within-generation plasticity while consistently strong (or weak) mortality selects for increased TGP. Such results provide us the first evidence for local adaptation in TGP and argue that divergent ecological conditions select for phenotypic responses within and across generations. PMID:26817775

Local adaptation in transgenerational responses to predators.

Science.gov (United States)

Walsh, Matthew R; Castoe, Todd; Holmes, Julian; Packer, Michelle; Biles, Kelsey; Walsh, Melissa; Munch, Stephan B; Post, David M

2016-01-27

Environmental signals can induce phenotypic changes that span multiple generations. Along with phenotypic responses that occur during development (i.e. 'within-generation' plasticity), such 'transgenerational plasticity' (TGP) has been documented in a diverse array of taxa spanning many environmental perturbations. New theory predicts that temporal stability is a key driver of the evolution of TGP. We tested this prediction using natural populations of zooplankton from lakes in Connecticut that span a large gradient in the temporal dynamics of predator-induced mortality. We reared more than 120 clones of Daphnia ambigua from nine lakes for multiple generations in the presence/absence of predator cues. We found that temporal variation in mortality selects for within-generation plasticity while consistently strong (or weak) mortality selects for increased TGP. Such results provide us the first evidence for local adaptation in TGP and argue that divergent ecological conditions select for phenotypic responses within and across generations. © 2016 The Author(s).

Adaptation response surfaces from an ensemble of wheat projections under climate change in Europe

Science.gov (United States)

Ruiz-Ramos, Margarita; Ferrise, Roberto

2016-04-01

preliminary ARSs show some adaptation options allow recover up to ca. 2000 kg/ha. Compared to the historical yields recorded at Lleida province (2550 kg/ha in 1981-2010) our results indicate that adaptation is feasible and may help to reduce detrimental effects of CC. Our analysis evaluates if the explored adaptations fulfill the biophysical requirements to become a practical adaptive solution. This study exemplifies how adaptation options and their impacts can be analyzed, evaluated and communicated in a context of high regional uncertainty for current and future conditions and for short to long-term perspective. This work was funded by MACSUR project within FACCE-JPI. References Abeledo, L.G., R. Savin and G.A. Slafer (2008). European Journal of Agronomy 28:541-550. Cartelle, J., A. Pedró, R. Savin, G.A. Slafer (2006) European Journal of Agronomy 25:365-371. Pirttioja, N., T. Carter, S. Fronzek, M. Bindi, H. Hoffmann, T. Palosuo, M. Ruiz-Ramos, F. Tao, M. Acutis, S. Asseng, P. Baranowski, B. Basso, P. Bodin, S. Buis, D. Cammarano, P. Deligios, M.-F. Destain, B. Dumont, R. Ewert, R. Ferrise, L. François, T. Gaiser, P. Hlavinka, I. Jacquemin, K.C. Kersebaum, C. Kollas, J. Krzyszczak, I.J. Lorite, J. Minet, M.I. Minguez, M. Montesino, M. Moriondo, C. Müller, C. Nendel, I. Öztürk, A. Perego, A. Rodríguez, A.C. Ruane, F. Ruget, M. Sanna, M.A. Semenov, C. Slawinski, P. Stratonovitch, I. Supit, K. Waha, E. Wang, L. Wu, Z. Zhao, and R.P. Rötter, 2015: A crop model ensemble analysis of temperature and precipitation effects on wheat yield across a European transect using impact response surfaces. Clim. Res., 65, 87-105, doi:10.3354/cr01322. IRS2 TEAM: Alfredo Rodríguez(1), Ignacio J. Lorite(3), Fulu Tao(4), Nina Pirttioja(5), Stefan Fronzek(5), Taru Palosuo(4), Timothy R. Carter(5), Marco Bindi(2), Jukka G Höhn(4), Kurt Christian Kersebaum(6), Miroslav Trnka(7,8), Holger Hoffmann(9), Piotr Baranowski(10), Samuel Buis(11), Davide Cammarano(12), Yi Chen(13,4), Paola Deligios

Adaptive Response Against Spontaneous Neoplastic Transformation In Vitro Induced by Ionizing Radiation

International Nuclear Information System (INIS)

Redpath, J. Leslie

2003-01-01

The goal of this project was to establish a dose response curve for radiation-induced neoplastic transformation of HeLa x skin fibroblast human hybrid cells in vitro under experimental conditions were an adaptive response, if it were induced, would have an opportunity to be expressed. During the first two years of the grant an exhaustive series of experiments were performed and the resulting data were reported at the 2000 Annual Meeting of the Radiation Research Society and then Subsequently published. The data showed that an adaptive response against spontaneous neoplastic transformation was seen up to doses of 10cGy of Cs-137 gamma rays. At dose of 30, 50 and 100 cGy the transformation frequencies were above background. This indicated that for this system, under the specific experimental conditions used, there was a threshold of somewhere between 10 and 30 cGy. The results also indicated some unexpected, though very interesting, correlations with relative risk estimates made from human epidemiologic studies

Dual function of CD70 in viral infection: modulator of early cytokine responses and activator of adaptive responses1

OpenAIRE

Allam, Atef; Swiecki, Melissa; Vermi, William; Ashwell, Jonathan D.; Colonna, Marco

2014-01-01

The role of the tumor necrosis factor family member CD70 in adaptive T cell responses has been intensively studied but its function in innate responses is still under investigation. Here we show that CD70 inhibits the early innate response to murine cytomegalovirus (MCMV) but is essential for the optimal generation of virus-specific CD8 T cells. CD70-/- mice reacted to MCMV infection with a robust type I interferon and proinflammatory cytokine response. This response was sufficient for initia...

RNA metabolism in Xylella fastidiosa during cold adaptation and survival responses

Science.gov (United States)

Fastidious plant pathogen Xylella fastidiosa has a reduced ability to adapt to cold temperatures, limiting persistence in perennial hosts, such as grapevine, growing in colder regions. RNA metabolism is an essential part of bacterial response to low temperature, including inducible expression of RNA...

When rapid adaptation paradigm is not too rapid: Evidence of face-sensitive N170 adaptation effects.

Science.gov (United States)

Tian, Tengxiang; Feng, Xue; Feng, Chunliang; Gu, Ruolei; Luo, Yue-Jia

2015-07-01

Recent findings have demonstrated that N170 adaptation effects evoked by face adaptors are general to face and non-face tests, implicating adaptor-locked interferences in the rapid adaptation paradigm. Here we examined the extent to which adaptor-locked interferences confound N170 adaptation effects in different experimental parameters by manipulating the stimulus onset asynchrony (SOA) duration and jitter between adaptors and tests. In the short SOA, those interferences were well visible for the grand-average ERP waveforms evoked by tests, and they are likely to render rapid adaptation paradigm with short SOA unreliable. The adaptor-locked interferences were attenuated by appropriately increasing SOA duration, such that face-sensitive adaptation effects were evident in the long SOA for both baseline-to-peak and peak-to-peak N170 measurements. These findings suggest that the rapid adaptation paradigm may work with a relative long SOA. Our findings provide useful information for future studies regarding the choosing of appropriate experimental parameters and measurements for the rapid adaptation paradigm. In addition, future studies are needed to investigate how to objectively subtract the overlaps of adaptors from tests and to validate the N170 adaptation effect with appropriate behavioral performance. Copyright © 2015 Elsevier B.V. All rights reserved.

Adaptive Interventions in Drug Court: A Pilot Experiment

Science.gov (United States)

Marlowe, Douglas B.; Festinger, David S.; Arabia, Patricia L.; Dugosh, Karen L.; Benasutti, Kathleen M.; Croft, Jason R.; McKay, James R.

2009-01-01

This pilot study (N = 30) experimentally examined the effects of an adaptive intervention in an adult misdemeanor drug court. The adaptive algorithm adjusted the frequency of judicial status hearings and clinical case-management sessions according to pre-specified criteria in response to participants' ongoing performance in the program. Results revealed the adaptive algorithm was acceptable to both clients and staff, feasible to implement with greater than 85% fidelity, and showed promise for eliciting clinically meaningful improvements in drug abstinence and graduation rates. Estimated effect sizes ranged from 0.40 to 0.60 across various dependent measures. Compared to drug court as-usual, participants in the adaptive condition were more likely to receive responses from the drug court team for inadequate performance in the program and received those responses after a substantially shorter period of time. This suggests the adaptive algorithm may have more readily focused the drug court team's attention on poorly-performing individuals, thus allowing the team to “nip problems in the bud” before they developed too fully. These preliminary data justify additional research evaluating the effects of the adaptive algorithm in a fully powered experimental trial. PMID:19724664

Global Megacities Differing Adaptation Responses to Climate Change: an Analysis of Annual Spend of Ten Major cities on the adaptation economy

Science.gov (United States)

Maslin, M. A.; Georgeson, L.

2015-12-01

Urban areas are increasingly at risk from climate change with negative impacts predicted for human health, the economy and ecosystems. These risks require responses from cities, to improve the resilience of their infrastructure, economy and environment to climate change. Policymakers need to understand what is already being spent on adaptation so that they can make more effective and comprehensive adaptation plans. Through the measurement of spend in the newly defined 'Adaptation Economy' we analysis the current efforts of 10 global megacities in adapting to climate change. These cities were chosen based on their size, geographical location and their developmental status. The cities are London, Paris, New York, Mexico City, Sao Paulo, Beijing, Mumbai, Jakarta, Lagos and Addis Ababa. It is important to study a range of cities in different regions of the world, with different climates and at different states of socio-economic development. While in economic terms, disaster losses from weather, climate and geophysical events are greater in developed countries, fatalities and economic losses as a proportion of GDP are higher in developing countries. In all cities examined the Adaptation Economy is still a small part of the overall economy accounting for a maximum of 0.3% of the Cities total GDP (GDPc). The differences in total spend are significant between cities in developed and rapidly emerging countries, compared to those in developing countries with a spend ranging from £16 million to £1,500 million. Comparing key sub sectors, we demonstrate that there are distinctive adaptation profiles with developing cities having a higher relative spend on health, while developed cities have a higher spend on disaster preparedness, ICT and professional services. Comparing spend per capita and as a percentage of GDPc demonstrates even more clearly disparities between the cities in the study; developing country cities spend half as much as a proportion of GPCc in some cases, and

Effect of low dose radiation in lymphocytes from children exposed to ionizing radiation after the Chernobyl accident. Cytogenetic, chromosome painting, GPA and adaptive response studies

International Nuclear Information System (INIS)

Padovani, L.; Appolloni, M.; Anzidei, P.; Spano, M.; Stronati, L.; Testa, A.; Mauro, F.

1997-01-01

The present study concerns the monitoring of some children coming from Byelorussian, Ukrainian and Russian republics, exposed to the fall-out, or to the initial acute dose of radiation with the aim of assessing the effects of ionizing radiation on human health and of verifying the persisting of chromosomal damage several years after the accident. Both structural chromosomes damage (conventional cytogenetic and chromosome painting) and molecular mutation (GPA) have been investigated, moreover the possible induction of an adaptive response has been tested. (author)

Adaptability: An Important Capacity for Effective Teachers

Science.gov (United States)

Collie, Rebecca J.; Martin, Andrew J.

2016-01-01

A defining feature of teaching work is that it involves novelty, change, and uncertainty on a daily basis. Being able to respond effectively to this change is known as adaptability. In this article, we discuss the importance of adaptability for teachers and their healthy and effective functioning in the workplace. We discuss approaches for…

Adaptive responses of cardiac function to fetal postural change as gestational age increases

Science.gov (United States)

Kim, Woo Jin; Choi, Hye Jin; Yang, Sun Young; Koo, Boo Hae; Ahn, Ki Hoon; Hong, Soon Cheol; Oh, Min-Jeong; Kim, Hai-Joong

2016-01-01

Objective The cardiovascular system maintains homeostasis through a series of adaptive responses to physiological requirements. However, little is known about the adaptation of fetal cardiac function to gravity, according to gestational age. In the present study, we aimed to evaluate the adaptive responses of cardiac function to postural changes, using Tei index measurements. Methods Fetal echocardiography and Doppler examination were performed on 114 women with vertex singleton pregnancies at 19 to 40 weeks' gestation. Participants were placed in an upright seated position, and the Tei index for fetal left ventricular cardiac function was measured. The women were then moved into a supine position and the Tei index was re-measured. Results The mean Tei index when measured in an upright seated position was significantly lower than that measured in a supine positioning for all fetuses (0.528±0.103 vs. 0.555±0.106, P=0.014, respectively). This difference was also noted in fetuses with a gestational age of 28–40 weeks (0.539±0.107 vs. 0.574±0.102, P=0.011, respectively). However, there was no difference in the Tei index between an upright seated and a supine position among fetuses with a gestational age of Postural changes from an upright seated to a supine position result in an increased Tei index after a gestational age of 28 weeks. This appears to reflect maturation in the adaptive responses of the fetal cardiovascular system to postural changes. PMID:27896244

Autologous Stem Cell Transplantation Disrupts Adaptive Immune Responses during Rebound Simian/Human Immunodeficiency Virus Viremia.

Science.gov (United States)

Reeves, Daniel B; Peterson, Christopher W; Kiem, Hans-Peter; Schiffer, Joshua T

2017-07-01

Primary HIV-1 infection induces a virus-specific adaptive/cytolytic immune response that impacts the plasma viral load set point and the rate of progression to AIDS. Combination antiretroviral therapy (cART) suppresses plasma viremia to undetectable levels that rebound upon cART treatment interruption. Following cART withdrawal, the memory component of the virus-specific adaptive immune response may improve viral control compared to primary infection. Here, using primary infection and treatment interruption data from macaques infected with simian/human immunodeficiency virus (SHIV), we observe a lower peak viral load but an unchanged viral set point during viral rebound. The addition of an autologous stem cell transplant before cART withdrawal alters viral dynamics: we found a higher rebound set point but similar peak viral loads compared to the primary infection. Mathematical modeling of the data that accounts for fundamental immune parameters achieves excellent fit to heterogeneous viral loads. Analysis of model output suggests that the rapid memory immune response following treatment interruption does not ultimately lead to better viral containment. Transplantation decreases the durability of the adaptive immune response following cART withdrawal and viral rebound. Our model's results highlight the impact of the endogenous adaptive immune response during primary SHIV infection. Moreover, because we capture adaptive immune memory and the impact of transplantation, this model will provide insight into further studies of cure strategies inspired by the Berlin patient. IMPORTANCE HIV patients who interrupt combination antiretroviral therapy (cART) eventually experience viral rebound, the return of viral loads to pretreatment levels. However, the "Berlin patient" remained free of HIV rebound over a decade after stopping cART. His cure is attributed to leukemia treatment that included an HIV-resistant stem cell transplant. Inspired by this case, we studied the impact

Adaptation.

Science.gov (United States)

Broom, Donald M

2006-01-01

The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

Low-Dose Radiation-Induced Adaptive Response in Polychromatic Mice Erythrocyte as Measured by Acridine Orange Stained Micronuleus Assay

International Nuclear Information System (INIS)

Hee-Sun, K.; Kwang-Hee, Y.; Cha-Soom, K.; Jung-Mi, C.; Gu-Choul, S.; Suk-Young, P.; Kyoung-H, C.; Chong-Soom, K.; Young-Khi, L.; Jae-Ho, W.

2004-01-01

The effect of conditioning pretreatment with 0.01Gy of gamma rays on micronucleated polychromatic erythrocyte (MN-PCE) induction by 2Gy of g-rays was determined in peripheral blood of C3H/He mice. The timing of their administration of challenge doses was 6hr. The response was determined by scoring of Acridine orange dye stained MN-PCEs. The results indicate that low dose gamma ray pretreatment does protect against MN-PCE induction by the challenge g-ray dose. Introduction: An adaptive response induced by low doses of ionizing radiation in vivo reported. Some research team reports that a reduction on MN-PCE of mice caused by the pretreatment was observed [1- 4]. However, there was variability in the amount of the response depending on the time and adaptive dose [3]. This is important because the variation of MN-PCE frequency with time could lead to differences in the interpretation. In this study, differences in the biological effects within the priming dose ranges are discussed. Materials and Methods: Specific pathogen free 5-week-old C3H/He mice, purchased from Shizuoka Laboratory Center (Japan), were kept in clean and conventional environment. When 6 weeks old, the animal were whole body irradiated using irradiator of IBL-437 (137Cs, 0.8Gy/min). After various time intervals, the two groups were administrated to adaptation dose and challenge dose of 0.01Gy and 2Gy, respectively. For experiments, sham-irradiated, only adaptive and challenge dose irradiated groups were run concurrently. Smears were stained and scored using Acridine orange dye method [2]. Statistically significant differences in MN-PCE frequency were determined by comparing tie individual values at each group with the respective control values (challenge dose irradiated group) by using the paired ttest. Results and Discussions: Induced MN by the challenge dose (2Gy) after the pretreatment with 0.01Gy is low to the one induced by the challenge dose alone. In the present study, this estimation for the

Error Decomposition and Adaptivity for Response Surface Approximations from PDEs with Parametric Uncertainty

KAUST Repository

Bryant, C. M.; Prudhomme, S.; Wildey, T.

2015-01-01

In this work, we investigate adaptive approaches to control errors in response surface approximations computed from numerical approximations of differential equations with uncertain or random data and coefficients. The adaptivity of the response surface approximation is based on a posteriori error estimation, and the approach relies on the ability to decompose the a posteriori error estimate into contributions from the physical discretization and the approximation in parameter space. Errors are evaluated in terms of linear quantities of interest using adjoint-based methodologies. We demonstrate that a significant reduction in the computational cost required to reach a given error tolerance can be achieved by refining the dominant error contributions rather than uniformly refining both the physical and stochastic discretization. Error decomposition is demonstrated for a two-dimensional flow problem, and adaptive procedures are tested on a convection-diffusion problem with discontinuous parameter dependence and a diffusion problem, where the diffusion coefficient is characterized by a 10-dimensional parameter space.

Strains of bacterial species induce a greatly varied acute adaptive immune response: The contribution of the accessory genome.

Directory of Open Access Journals (Sweden)

Uri Sela

2018-01-01

Full Text Available A fundamental question in human susceptibility to bacterial infections is to what extent variability is a function of differences in the pathogen species or in individual humans. To focus on the pathogen species, we compared in the same individual the human adaptive T and B cell immune response to multiple strains of two major human pathogens, Staphylococcus aureus and Streptococcus pyogenes. We found wide variability in the acute adaptive immune response induced by various strains of a species, with a unique combination of activation within the two arms of the adaptive response. Further, this was also accompanied by a dramatic difference in the intensity of the specific protective T helper (Th response. Importantly, the same immune response differences induced by the individual strains were maintained across multiple healthy human donors. A comparison of isogenic phage KO strains, demonstrated that of the pangenome, prophages were the major contributor to inter-strain immune heterogeneity, as the T cell response to the remaining "core genome" was noticeably blunted. Therefore, these findings extend and modify the notion of an adaptive response to a pathogenic bacterium, by implying that the adaptive immune response signature of a bacterial species should be defined either per strain or alternatively to the species' 'core genome', common to all of its strains. Further, our results demonstrate that the acquired immune response variation is as wide among different strains within a single pathogenic species as it is among different humans, and therefore may explain in part the clinical heterogeneity observed in patients infected with the same species.

Inhibition of glutathione synthesis eliminates the adaptive response of ascitic hepatoma 22 cells to nedaplatin that targets thioredoxin reductase

Energy Technology Data Exchange (ETDEWEB)

Wang, Yijun [School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, Anhui (China); Lu, Hongjuan [Productivity Center of Jiangsu Province, Nanjing 210042, Jiangsu (China); Wang, Dongxu; Li, Shengrong; Sun, Kang; Wan, Xiaochun [School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, Anhui (China); Taylor, Ethan Will [Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27402 (United States); Zhang, Jinsong, E-mail: zjs@ahau.edu.cn [School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, Anhui (China)

2012-12-15

Thioredoxin reductase (TrxR) is a target for cancer therapy and the anticancer mechanism of cisplatin involves TrxR inhibition. We hypothesize that the anticancer drug nedaplatin (NDP), an analogue of cisplatin and a second-generation platinum complex, also targets TrxR. Furthermore, we investigate whether the therapeutic efficacy of NDP can be enhanced by simultaneous modulation of 1) TrxR, via NDP, and 2) glutathione (GSH), via the GSH synthesis inhibitor buthionine sulfoximine (BSO). Mice bearing ascitic hepatoma 22 (H22) cells were treated with NDP alone or NDP plus BSO. TrxR activity of H22 cells was inhibited by NDP in a dose-dependent manner. A high correlation between the inhibition of TrxR activity at 6 h and the inhibition of ascitic fluid volume at 72 h was established (r = 0.978, p < 0.01). As an adaptive response, the viable ascitic cancer cells after NDP treatment displayed an enlarged cell phenotype, assembled with several-fold more antioxidant enzymes and GSH-predominant non-protein free thiols. This adaptive response was largely eliminated when BSO was co-administered with NDP, leading to the decimation of the H22 cell population without enhancing renal toxicity, since at this dose, NDP did not inhibit renal TrxR activity. In conclusion, the pharmacological effect of NDP involves TrxR inhibition, and the adaptive response of NDP-treated ascitic H22 cells can be efficiently counteracted by BSO. Simultaneous modulation of TrxR and GSH on ascitic H22 cells using NDP plus BSO greatly enhances therapeutic efficacy as compared with the single modulation of TrxR using NDP alone. -- Highlights: ► Nedaplatin at a pharmacological dose inhibits TrxR in cancer cells but not in kidney. ► The nedaplatin-treated cancer cells exhibit adaptive response. ► Buthionine sulfoximine inhibits glutathione in both cancer cells and kidney. ► Buthionine sulfoximine counteracts the adaptive response to the nedaplatin treatment. ► Buthionine sulfoximine does not

Inhibition of glutathione synthesis eliminates the adaptive response of ascitic hepatoma 22 cells to nedaplatin that targets thioredoxin reductase

International Nuclear Information System (INIS)

Wang, Yijun; Lu, Hongjuan; Wang, Dongxu; Li, Shengrong; Sun, Kang; Wan, Xiaochun; Taylor, Ethan Will; Zhang, Jinsong

2012-01-01

Thioredoxin reductase (TrxR) is a target for cancer therapy and the anticancer mechanism of cisplatin involves TrxR inhibition. We hypothesize that the anticancer drug nedaplatin (NDP), an analogue of cisplatin and a second-generation platinum complex, also targets TrxR. Furthermore, we investigate whether the therapeutic efficacy of NDP can be enhanced by simultaneous modulation of 1) TrxR, via NDP, and 2) glutathione (GSH), via the GSH synthesis inhibitor buthionine sulfoximine (BSO). Mice bearing ascitic hepatoma 22 (H22) cells were treated with NDP alone or NDP plus BSO. TrxR activity of H22 cells was inhibited by NDP in a dose-dependent manner. A high correlation between the inhibition of TrxR activity at 6 h and the inhibition of ascitic fluid volume at 72 h was established (r = 0.978, p < 0.01). As an adaptive response, the viable ascitic cancer cells after NDP treatment displayed an enlarged cell phenotype, assembled with several-fold more antioxidant enzymes and GSH-predominant non-protein free thiols. This adaptive response was largely eliminated when BSO was co-administered with NDP, leading to the decimation of the H22 cell population without enhancing renal toxicity, since at this dose, NDP did not inhibit renal TrxR activity. In conclusion, the pharmacological effect of NDP involves TrxR inhibition, and the adaptive response of NDP-treated ascitic H22 cells can be efficiently counteracted by BSO. Simultaneous modulation of TrxR and GSH on ascitic H22 cells using NDP plus BSO greatly enhances therapeutic efficacy as compared with the single modulation of TrxR using NDP alone. -- Highlights: ► Nedaplatin at a pharmacological dose inhibits TrxR in cancer cells but not in kidney. ► The nedaplatin-treated cancer cells exhibit adaptive response. ► Buthionine sulfoximine inhibits glutathione in both cancer cells and kidney. ► Buthionine sulfoximine counteracts the adaptive response to the nedaplatin treatment. ► Buthionine sulfoximine does not

Finite-time hybrid projective synchronization of the drive-response complex networks with distributed-delay via adaptive intermittent control

Science.gov (United States)

Cheng, Lin; Yang, Yongqing; Li, Li; Sui, Xin

2018-06-01

This paper studies the finite-time hybrid projective synchronization of the drive-response complex networks. In the model, general transmission delays and distributed delays are also considered. By designing the adaptive intermittent controllers, the response network can achieve hybrid projective synchronization with the drive system in finite time. Based on finite-time stability theory and several differential inequalities, some simple finite-time hybrid projective synchronization criteria are derived. Two numerical examples are given to illustrate the effectiveness of the proposed method.

Real-Time Molecular Monitoring of Chemical Environment in ObligateAnaerobes during Oxygen Adaptive Response

Energy Technology Data Exchange (ETDEWEB)

Holman, Hoi-Ying N.; Wozei, Eleanor; Lin, Zhang; Comolli, Luis R.; Ball, David. A.; Borglin, Sharon; Fields, Matthew W.; Hazen, Terry C.; Downing, Kenneth H.

2009-02-25

Determining the transient chemical properties of the intracellular environment canelucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms which enable some obligate anaerobic bacteria to survive a sudden exposure to oxygen. Here we used high-resolution Fourier Transform Infrared (FTIR) spectromicroscopy to continuously follow cellular chemistry within living obligate anaerobes by monitoring hydrogen bonding in their cellular water. We observed a sequence of wellorchestrated molecular events that correspond to changes in cellular processes in those cells that survive, but only accumulation of radicals in those that do not. We thereby can interpret the adaptive response in terms of transient intracellular chemistry and link it to oxygen stress and survival. This ability to monitor chemical changes at the molecular level can yield important insights into a wide range of adaptive responses.

Adaptive response of Chironomus riparius populations exposed to uranium contaminated sediments during consecutive generations

International Nuclear Information System (INIS)

Dias, V.

2010-01-01

The intensity of selection on populations caused by polluted environment often exceeds which is caused by an unpolluted environment. Therefore, micro evolution can occur in response to this anthropic-directional force over a short period. In this context, this thesis focused on studying phenotypic changes in Chironomus riparius populations exposed during several consecutive generations to uranium-contaminated sediments. In laboratory-controlled conditions experiments were conducted with same origin populations exposed to a range of uranium concentration inducing toxic effects. Over eight-generations of exposure, life-history traits measures revealed micro evolution in exposed populations, including increase of adult reproductive success. Other experiments (acute toxicity test, common garden experiment) performed in parallel enabled to link these micro evolution with a tolerance induction, as a consequence of genetic adaptation. Nonetheless this adaptation also induced cost in terms of fitness and genetic diversity for pre-exposed populations. These results lead to the hypothesis of a selection by uranium that acted sequentially on populations. They also underline the need to better-understand the adaptive mechanisms to better assess the ecological consequences of chronic exposure of populations to a pollutant. (author)

Adaptive PID and Model Reference Adaptive Control Switch Controller for Nonlinear Hydraulic Actuator

Directory of Open Access Journals (Sweden)

Xin Zuo

2017-01-01

Full Text Available Nonlinear systems are modeled as piecewise linear systems at multiple operating points, where the operating points are modeled as switches between constituent linearized systems. In this paper, adaptive piecewise linear switch controller is proposed for improving the response time and tracking performance of the hydraulic actuator control system, which is essentially piecewise linear. The controller composed of PID and Model Reference Adaptive Control (MRAC adaptively chooses the proportion of these two components and makes the designed system have faster response time at the transient phase and better tracking performance, simultaneously. Then, their stability and tracking performance are analyzed and evaluated by the hydraulic actuator control system, the hydraulic actuator is controlled by the electrohydraulic system, and its model is built, which has piecewise linear characteristic. Then the controller results are compared between PID and MRAC and the switch controller designed in this paper is applied to the hydraulic actuator; it is obvious that adaptive switch controller has better effects both on response time and on tracking performance.

Adaptive all the way down: building responsive materials from hierarchies of chemomechanical feedback.

Science.gov (United States)

Grinthal, Alison; Aizenberg, Joanna

2013-09-07

A living organism is a bundle of dynamic, integrated adaptive processes: not only does it continuously respond to constant changes in temperature, sunlight, nutrients, and other features of its environment, but it does so by coordinating hierarchies of feedback among cells, tissues, organs, and networks all continuously adapting to each other. At the root of it all is one of the most fundamental adaptive processes: the constant tug of war between chemistry and mechanics that interweaves chemical signals with endless reconfigurations of macromolecules, fibers, meshworks, and membranes. In this tutorial we explore how such chemomechanical feedback - as an inherently dynamic, iterative process connecting size and time scales - can and has been similarly evoked in synthetic materials to produce a fascinating diversity of complex multiscale responsive behaviors. We discuss how chemical kinetics and architecture can be designed to generate stimulus-induced 3D spatiotemporal waves and topographic patterns within a single bulk material, and how feedback between interior dynamics and surface-wide instabilities can further generate higher order buckling and wrinkling patterns. Building on these phenomena, we show how yet higher levels of feedback and spatiotemporal complexity can be programmed into hybrid materials, and how these mechanisms allow hybrid materials to be further integrated into multicompartmental systems capable of hierarchical chemo-mechano-chemical feedback responses. These responses no doubt represent only a small sample of the chemomechanical feedback behaviors waiting to be discovered in synthetic materials, and enable us to envision nearly limitless possibilities for designing multiresponsive, multifunctional, self-adapting materials and systems.

Effect of visuomotor-map uncertainty on visuomotor adaptation.

Science.gov (United States)

Saijo, Naoki; Gomi, Hiroaki

2012-03-01

Vision and proprioception contribute to generating hand movement. If a conflict between the visual and proprioceptive feedback of hand position is given, reaching movement is disturbed initially but recovers after training. Although previous studies have predominantly investigated the adaptive change in the motor output, it is unclear whether the contributions of visual and proprioceptive feedback controls to the reaching movement are modified by visuomotor adaptation. To investigate this, we focused on the change in proprioceptive feedback control associated with visuomotor adaptation. After the adaptation to gradually introduce visuomotor rotation, the hand reached the shifted position of the visual target to move the cursor to the visual target correctly. When the cursor feedback was occasionally eliminated (probe trial), the end point of the hand movement was biased in the visual-target direction, while the movement was initiated in the adapted direction, suggesting the incomplete adaptation of proprioceptive feedback control. Moreover, after the learning of uncertain visuomotor rotation, in which the rotation angle was randomly fluctuated on a trial-by-trial basis, the end-point bias in the probe trial increased, but the initial movement direction was not affected, suggesting a reduction in the adaptation level of proprioceptive feedback control. These results suggest that the change in the relative contribution of visual and proprioceptive feedback controls to the reaching movement in response to the visuomotor-map uncertainty is involved in visuomotor adaptation, whereas feedforward control might adapt in a manner different from that of the feedback control.

A cascade reaction network mimicking the basic functional steps of adaptive immune response.

Science.gov (United States)

Han, Da; Wu, Cuichen; You, Mingxu; Zhang, Tao; Wan, Shuo; Chen, Tao; Qiu, Liping; Zheng, Zheng; Liang, Hao; Tan, Weihong

2015-10-01

Biological systems use complex 'information-processing cores' composed of molecular networks to coordinate their external environment and internal states. An example of this is the acquired, or adaptive, immune system (AIS), which is composed of both humoral and cell-mediated components. Here we report the step-by-step construction of a prototype mimic of the AIS that we call an adaptive immune response simulator (AIRS). DNA and enzymes are used as simple artificial analogues of the components of the AIS to create a system that responds to specific molecular stimuli in vitro. We show that this network of reactions can function in a manner that is superficially similar to the most basic responses of the vertebrate AIS, including reaction sequences that mimic both humoral and cellular responses. As such, AIRS provides guidelines for the design and engineering of artificial reaction networks and molecular devices.

Temporal partitioning of adaptive responses of the murine heart to fasting.

Science.gov (United States)

Brewer, Rachel A; Collins, Helen E; Berry, Ryan D; Brahma, Manoja K; Tirado, Brian A; Peliciari-Garcia, Rodrigo A; Stanley, Haley L; Wende, Adam R; Taegtmeyer, Heinrich; Rajasekaran, Namakkal Soorappan; Darley-Usmar, Victor; Zhang, Jianhua; Frank, Stuart J; Chatham, John C; Young, Martin E

2018-03-15

Recent studies suggest that the time of day at which food is consumed dramatically influences clinically-relevant cardiometabolic parameters (e.g., adiposity, insulin sensitivity, and cardiac function). Meal feeding benefits may be the result of daily periods of feeding and/or fasting, highlighting the need for improved understanding of the temporal adaptation of cardiometabolic tissues (e.g., heart) to fasting. Such studies may provide mechanistic insight regarding how time-of-day-dependent feeding/fasting cycles influence cardiac function. We hypothesized that fasting during the sleep period elicits beneficial adaptation of the heart at transcriptional, translational, and metabolic levels. To test this hypothesis, temporal adaptation was investigated in wild-type mice fasted for 24-h, or for either the 12-h light/sleep phase or the 12-h dark/awake phase. Fasting maximally induced fatty acid responsive genes (e.g., Pdk4) during the dark/active phase; transcriptional changes were mirrored at translational (e.g., PDK4) and metabolic flux (e.g., glucose/oleate oxidation) levels. Similarly, maximal repression of myocardial p-mTOR and protein synthesis rates occurred during the dark phase; both parameters remained elevated in the heart of fasted mice during the light phase. In contrast, markers of autophagy (e.g., LC3II) exhibited peak responses to fasting during the light phase. Collectively, these data show that responsiveness of the heart to fasting is temporally partitioned. Autophagy peaks during the light/sleep phase, while repression of glucose utilization and protein synthesis is maximized during the dark/active phase. We speculate that sleep phase fasting may benefit cardiac function through augmentation of protein/cellular constituent turnover. Copyright © 2018 Elsevier Inc. All rights reserved.

Adaptive Surrogate Modeling for Response Surface Approximations with Application to Bayesian Inference

KAUST Repository

Prudhomme, Serge

2015-01-07

The need for surrogate models and adaptive methods can be best appreciated if one is interested in parameter estimation using a Bayesian calibration procedure for validation purposes. We extend here our latest work on error decomposition and adaptive refinement for response surfaces to the development of surrogate models that can be substituted for the full models to estimate the parameters of Reynolds-averaged Navier-Stokes models. The error estimates and adaptive schemes are driven here by a quantity of interest and are thus based on the approximation of an adjoint problem. We will focus in particular to the accurate estimation of evidences to facilitate model selection. The methodology will be illustrated on the Spalart-Allmaras RANS model for turbulence simulation.

Adaptive Surrogate Modeling for Response Surface Approximations with Application to Bayesian Inference

KAUST Repository

Prudhomme, Serge

2015-01-01

The need for surrogate models and adaptive methods can be best appreciated if one is interested in parameter estimation using a Bayesian calibration procedure for validation purposes. We extend here our latest work on error decomposition and adaptive refinement for response surfaces to the development of surrogate models that can be substituted for the full models to estimate the parameters of Reynolds-averaged Navier-Stokes models. The error estimates and adaptive schemes are driven here by a quantity of interest and are thus based on the approximation of an adjoint problem. We will focus in particular to the accurate estimation of evidences to facilitate model selection. The methodology will be illustrated on the Spalart-Allmaras RANS model for turbulence simulation.

Biological Bases for Radiation Adaptive Responses in the Lung

Energy Technology Data Exchange (ETDEWEB)

Scott, Bobby R. [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States); Lin, Yong [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States); Wilder, Julie [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States); Belinsky, Steven [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States)

2015-03-01

Our main research objective was to determine the biological bases for low-dose, radiation-induced adaptive responses in the lung, and use the knowledge gained to produce an improved risk model for radiation-induced lung cancer that accounts for activated natural protection, genetic influences, and the role of epigenetic regulation (epiregulation). Currently, low-dose radiation risk assessment is based on the linear-no-threshold hypothesis, which now is known to be unsupported by a large volume of data.

The congruency sequence effect 3.0: a critical test of conflict adaptation.

Science.gov (United States)

Duthoo, Wout; Abrahamse, Elger L; Braem, Senne; Boehler, C Nico; Notebaert, Wim

2014-01-01

Over the last two decades, the congruency sequence effect (CSE) -the finding of a reduced congruency effect following incongruent trials in conflict tasks- has played a central role in advancing research on cognitive control. According to the influential conflict-monitoring account, the CSE reflects adjustments in selective attention that enhance task focus when needed, often termed conflict adaptation. However, this dominant interpretation of the CSE has been called into question by several alternative accounts that stress the role of episodic memory processes: feature binding and (stimulus-response) contingency learning. To evaluate the notion of conflict adaptation in accounting for the CSE, we construed versions of three widely used experimental paradigms (the colour-word Stroop, picture-word Stroop and flanker task) that effectively control for feature binding and contingency learning. Results revealed that a CSE can emerge in all three tasks. This strongly suggests a contribution of attentional control to the CSE and highlights the potential of these unprecedentedly clean paradigms for further examining cognitive control.

Climate change adaptation : planning for BC

International Nuclear Information System (INIS)

Harford, D.; Vanderwill, C.; Church, A.

2008-11-01

This paper explored climate change challenges facing British Columbia in the context of 9 topical issues, notably biodiversity, extreme events, energy, water supply, crop adaptation, health risks, sea level rise, population dynamics and new technologies. Each issue was summarized in terms of threats, current responses in British Columbia and precedents being set in Canada. The key principles of adaptation to climate change were also reviewed. In addition, the paper explored ways to adopt smart adaptation strategies-policy responses to climate change that cut across all major government functions, such as infrastructure, energy, water, economic development, resource management and agriculture. The paper emphasized that strategies that respond to the climate challenge should acknowledge the links between adaptation and mitigation, or emissions reduction. Both concepts need major investment in research, education and infrastructure to support comprehensive, effective responses. refs., tabs., figs

Low-dose radiation-induced adaptive response in bone marrow cells of mice

International Nuclear Information System (INIS)

Farooqi, Zeba; Kesavan, P.C.

1993-01-01

Using bone marrow cells of whole body irradiated mice, the cytogenetic adaptive response induced by low conditioning doses of gamma-rays was investigated. The conditioning doses (0.025 and 0.05 Gy) were given at a dose-rate of 1.67 Gy/min. The challenging dose of 1 Gy was given at a dose-rate of 0.045 Gy/s. The challenging dose was given at different time intervals after the conditioning dose. The time intervals between the conditioning dose and challenging dose were 2, 7.5, 13, 18.5 and 24 h. When the time interval between the conditioning dose and the challenging dose was 2 h, both conditioning doses (0.025 and 0.05 Gy) reduced the frequency of MNPCEs and chromosomal aberrations in the bone marrow cells. The data collected at different time intervals (7.5, 13, 18.5 h) reveal that the radioadaptive response persisted for a longer time when the lower conditioning dose (0.025 Gy) was given. With the higher conditioning dose (0.05 Gy), the radioadaptive response disappeared after a time interval of 13 h. When the time interval between the conditioning dose and the challenging doses was 18.5 or 24 h, only the lower conditioning dose appeared effective in inducing the radioadaptive response

DNA damage response pathway in radioadaptive response.

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Sasaki, Masao S; Ejima, Yosuke; Tachibana, Akira; Yamada, Toshiko; Ishizaki, Kanji; Shimizu, Takashi; Nomura, Taisei

2002-07-25

Radioadaptive response is a biological defense mechanism in which low-dose ionizing irradiation elicits cellular resistance to the genotoxic effects of subsequent irradiation. However, its molecular mechanism remains largely unknown. We previously demonstrated that the dose recognition and adaptive response could be mediated by a feedback signaling pathway involving protein kinase C (PKC), p38 mitogen activated protein kinase (p38MAPK) and phospholipase C (PLC). Further, to elucidate the downstream effector pathway, we studied the X-ray-induced adaptive response in cultured mouse and human cells with different genetic background relevant to the DNA damage response pathway, such as deficiencies in TP53, DNA-PKcs, ATM and FANCA genes. The results showed that p53 protein played a key role in the adaptive response while DNA-PKcs, ATM and FANCA were not responsible. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), mimicked the priming irradiation in that the inhibitor alone rendered the cells resistant against the induction of chromosome aberrations and apoptosis by the subsequent X-ray irradiation. The adaptive response, whether it was afforded by low-dose X-rays or wortmannin, occurred in parallel with the reduction of apoptotic cell death by challenging doses. The inhibitor of p38MAPK which blocks the adaptive response did not suppress apoptosis. These observations indicate that the adaptive response and apoptotic cell death constitute a complementary defense system via life-or-death decisions. The p53 has a pivotal role in channeling the radiation-induced DNA double-strand breaks (DSBs) into an adaptive legitimate repair pathway, where the signals are integrated into p53 by a circuitous PKC-p38MAPK-PLC damage sensing pathway, and hence turning off the signals to an alternative pathway to illegitimate repair and apoptosis. A possible molecular mechanism of adaptive response to low-dose ionizing irradiation has been discussed in relation to

Increased innate and adaptive immune responses in induced sputum of young smokers

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Agnese Kislina

2015-01-01

Conclusions: This study demonstrates that young smokers have early inflammatory changes in their airways that not only initiate nonspecific mechanisms recruiting neutrophils, but also involve specific immune mechanisms with recruitment of T regulatory lymphocytes. The lymphocyte response is probably adaptive.

Mobilisation, politics, investment and constant adaptation: lessons from the Australian health-promotion response to HIV.

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Brown, Graham; O'Donnell, Daryl; Crooks, Levinia; Lake, Rob

2014-04-01

The Australian response to HIV oversaw one of the most rapid and sustained changes in community behaviour in Australia's health-promotion history. The combined action of communities of gay men, sex workers, people who inject drugs, people living with HIV and clinicians working in partnership with government, public health and research has been recognised for many years as highly successful in minimising the HIV epidemic. This article will show how the Australian HIV partnership response moved from a crisis response to a constant and continuously adapting response, with challenges in sustaining the partnership. Drawing on key themes, lessons for broader health promotion are identified. The Australian HIV response has shown that a partnership that is engaged, politically active, adaptive and resourced to work across multiple social, structural, behavioural and health-service levels can reduce the transmission and impact of HIV. The experience of the response to HIV, including its successes and failures, has lessons applicable across health promotion. This includes the need to harness community mobilisation and action; sustain participation, investment and leadership across the partnership; commit to social, political and structural approaches; and build and use evidence from multiple sources to continuously adapt and evolve. So what? The Australian HIV response was one of the first health issues to have the Ottawa Charter embedded from the beginning, and has many lessons to offer broader health promotion and common challenges. As a profession and a movement, health promotion needs to engage with the interactions and synergies across the promotion of health, learn from our evidence, and resist the siloing of our responses.

Adapting the helpful responses questionnaire to assess communication skills involved in delivering contingency management: preliminary psychometrics.

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Hartzler, Bryan

2015-08-01

A paper/pencil instrument, adapted from Miller and colleagues' (1991) Helpful Responses Questionnaire (HRQ), was developed to assess clinician skill with core communicative aspects involved in delivering contingency management (CM). The instrument presents a single vignette consisting of six points of client dialogue to which respondents write 'what they would say next.' In the context of an implementation/effectiveness hybrid trial, 19 staff clinicians at an opiate treatment program completed serial training outcome assessments before, following, and three months after CM training. Assessments included this adaptation of the HRQ, a multiple-choice CM knowledge test, and a recorded standardized patient encounter scored for CM skillfulness. Study results reveal promising psychometric properties for the instrument, including strong scoring reliability, internal consistency, concurrent and predictive validity, test-retest reliability and sensitivity to training effects. These preliminary findings suggest the instrument is a viable, practical method to assess clinician skill in communicative aspects of CM delivery. Copyright © 2015 Elsevier Inc. All rights reserved.

Mutagenic adaptive response to high-LET radiation in human lymphoblastoid cells exposed to X-rays.

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Varès, Guillaume; Wang, Bing; Tanaka, Kaoru; Kakimoto, Ayana; Eguchi-Kasai, Kyomi; Nenoi, Mitsuru

2011-01-10

The ability of cells to adapt low-dose or low-dose rate radiation is well known. High-LET radiation has unique characteristics, and the data concerning low doses effects and high-LET radiation remain fragmented. In this study, we assessed in vitro the ability of low doses of X-rays to induce an adaptive response (AR) to a subsequent challenging dose of heavy-ion radiation. Lymphoblastoid cells (TK6, AHH-1, NH32) were exposed to priming 0.02-0.1Gy X-rays, followed 6h later by challenging 1Gy heavy-ion radiation (carbon-ion: 20 and 40keV/μm, neon-ion: 150keV/μm). Pre-exposure of p53-competent cells resulted in decreased mutation frequencies at hypoxanthine-guanine phosphoribosyl transferase locus and different H2AX phosphorylation kinetics, as compared to cells exposed to challenging radiation alone. This phenomenon did not seem to be linked with cell cycle effects or radiation-induced apoptosis. Taken together, our results suggested the existence of an AR to mutagenic effects of heavy-ion radiation in lymphoblastoid cells and the involvement of double-strand break repair mechanisms. Copyright © 2010 Elsevier B.V. All rights reserved.

Transgenerational plasticity is adaptive in the wild.

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Galloway, Laura F; Etterson, Julie R

2007-11-16

Plants exhibit adaptive responses to light, but it is not known whether parental plants transmit environmental cues that elicit adaptive responses in offspring. We show that offspring life history (annual versus biennial) is influenced by the maternal light environment (understory versus light gap). This transgenerational plasticity is adaptive when offspring are grown in their maternal light environment, where seeds typically disperse. Projections of population growth show that plants that are appropriately cued for their light environment through maternal effects have 3.4 times greater fitness than otherwise. Transgenerational plasticity has evolved in response to natural variation in light and provides a flexible mechanism by which sedentary organisms cope with heterogeneous environments.

Radiation-induced adaptive response in fetal mice: a micro-array study

International Nuclear Information System (INIS)

Vares, G.; Bing, Wang; Mitsuru, Nenoi; Tetsuo, Nakajima; Kaoru, Tanaka; Isamu, Hayata

2006-01-01

Exposure of sublethal doses of ionizing radiation can induce protective mechanisms against a subsequent higher dose irradiation. This phenomenon called radio-adaptation (or adaptive response - AR), has been described in a wide range of biological models. In a series of studies, we demonstrated the existence of a radiation-induced AR in mice during late organogenesis. For better understanding of molecular mechanisms underlying AR in our model, we performed a global analysis of transcriptome regulations in cells collected from whole mouse fetuses. Using cDNA micro-arrays, we studied gene expression in these cells after in utero priming exposure to irradiation. Several combinations of radiation dose and dose-rate were applied to induce or not an AR in our system. Gene regulation was observed after exposure to priming radiation in each condition. Student's t-test was performed in order to identify genes whose expression modulation was specifically different in AR-inducing an( non-AR-inducing conditions. Genes were ranked according to their ability in discriminating AR-specific modulations. Since AR genes were implicated in variety of functions and cellular processes, we applied a functional classification algorithm, which clustered genes in a limited number of functionally related group: We established that AR genes are significantly enriched for specific keywords. Our results show a significant modulation of genes implicated in signal transduction pathways. No AR-specific alteration of DNA repair could be observed. Nevertheless, it is likely that modulation of DNA repair activity results, at least partly, from post-transcriptional regulation. One major hypothesis is that de-regulations of signal transduction pathways and apoptosis may be responsible for AR phenotype. In previous work, we demonstrated that radiation-induced AR in mice during organogenesis is related to Trp53 gene status and to the occurrence of radiation-induced apoptosis. Other work proposed that p53

A lower dose threshold for the in vivo protective adaptive response to radiation. Tumorigenesis in chronically exposed normal and Trp53 heterozygous C57BL/6 mice

International Nuclear Information System (INIS)

Mitchel, R.E.J.; Burchart, P.; Wyatt, H.

2008-01-01

Low doses of ionizing radiation to cells and animals may induce adaptive responses that reduce the risk of cancer. However, there are upper dose thresholds above which these protective adaptive responses do not occur. We have now tested the hypothesis that there are similar lower dose thresholds that must be exceeded in order to induce protective effects in vivo. We examined the effects of low dose/low dose rate fractionated exposures on cancer formation in Trp53 normal or cancer-prone Trp53 heterozygous female C57BL/6 mice. Beginning at 6 weeks of age, mice were exposed 5 days/week to single daily doses (0.33 mGy, 0.7 mGy/h) totaling 48, 97 or 146 mGy over 30, 60 or 90 weeks. The exposures for shorter times (up to 60 weeks) appeared to be below the level necessary to induce overall protective adaptive responses in Trp53 normal mice, and detrimental effects (shortened lifespan, increased frequency) evident for only specific tumor types (B- and T-cell lymphomas), were produced. Only when the exposures were continued for 90 weeks did the dose become sufficient to induce protective adaptive responses, balancing the detrimental effects for these specific cancers, and reducing the risk level back to that of the unexposed animals. Detrimental effects were not seen for other tumor types, and a protective effect was seen for sarcomas after 60 weeks of exposure, which was then lost when the exposure continued for 90 weeks. As previously shown for the upper dose threshold for protection by low doses, the lower dose boundary between protection and harm was influenced by Trp53 functionality. Neither protection nor harm was observed in exposed Trp53 heterozygous mice, indicating that reduced Trp53 function raises the lower dose/dose rate threshold for both detrimental and protective tumorigenic effects. (author)

Predictive and Reactive Locomotor Adaptability in Healthy Elderly: A Systematic Review and Meta-Analysis.

Science.gov (United States)

Bohm, Sebastian; Mademli, Lida; Mersmann, Falk; Arampatzis, Adamantios

2015-12-01

Locomotor adaptability is based on the implementation of error-feedback information from previous perturbations to predictively adapt to expected perturbations (feedforward) and to facilitate reactive responses in recurring unexpected perturbations ('savings'). The effect of aging on predictive and reactive adaptability is yet unclear. However, such understanding is fundamental for the design and application of effective interventions targeting fall prevention. We systematically searched the Web of Science, MEDLINE, Embase and Science Direct databases as well as the reference lists of the eligible articles. A study was included if it addressed an investigation of the locomotor adaptability in response to repeated mechanical movement perturbations of healthy older adults (≥60 years). The weighted average effect size (WAES) of the general adaptability (adaptive motor responses to repeated perturbations) as well as predictive (after-effects) and reactive adaptation (feedback responses to a recurring unexpected perturbation) was calculated and tested for an overall effect. A subgroup analysis was performed regarding the factor age group [i.e., young (≤35 years) vs. older adults]. Furthermore, the methodological study quality was assessed. The review process yielded 18 studies [1009 participants, 613 older adults (70 ± 4 years)], which used various kinds of locomotor tasks and perturbations. The WAES for the general locomotor adaptability was 1.21 [95% confidence interval (CI) 0.68-1.74, n = 11] for the older and 1.39 (95% CI 0.90-1.89, n = 10) for the young adults with a significant (p locomotor adaptability in general and predictive and reactive adaptation in particular remain highly effective in the elderly, showing only minor, not statistically significant age-related deficits. Consequently, interventions which use adaptation and learning paradigms including the application of the mechanisms responsible for an effective predictive and reactive dynamic stability

An adaptive response to alkylating agents in Aspergillus nidulans.

Science.gov (United States)

Hooley, P; Shawcross, S G; Strike, P

1988-11-01

A simple method is described for demonstrating adaptation to alkylation damage in Aspergillus nidulans. One wild type, two MNNG-sensitive, and one MNNG-resistant strain all showed improvement in colony growth when challenged with MNNG following appropriate inducing pretreatments. Other alkylating agents (MMS, EMS) could also adapt mycelium to later MNNG challenge, while 4NQO and UV could not. The inducible effect was not transmissible through conidia. A standard reversion assay based upon methG proved impractical for studying mutation frequencies during alkylation treatments owing to variations in MNNG resistance amongst revertants.

Adaptive and maladaptive cortisol responses to pediatric obesity.

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Soros, Arlette; Zadik, Zvi; Chalew, Stuart

2008-09-01

The recent unprecedented increase of childhood obesity has led to an alarming rise in type 2 diabetes mellitus (T2D) among these children. The process underlying the progression from simple obesity to T2D is not well understood. Cortisol is a candidate factor in the pathogenesis of T2D, as it can exacerbate insulin resistance and provoke other disturbances of the metabolic syndrome. The 24-h integrated concentration (IC) of cortisol is suppressed in non-diabetic obese children compared to lean children. This difference in IC-cortisol is not due to changes in cortisol binding globulin or plasma cortisol to cortisone ratio between groups. In obese individuals, IC-cortisol suppression disappears with age after adolescence, which corresponds with increasing occurrence of T2D and other metabolic disorders of obesity. We consider the IC-cortisol levels of lean insulin sensitive children to be metabolically inappropriate for obese insulin resistant children. Thus, we hypothesize that suppression of IC-cortisol is an important adaptive response to obesity (cortisol adaptive suppression) in childhood that prevents pediatric T2D while failure to suppress IC-cortisol (cortisol suppression failure) exacerbates insulin resistance and contributes to the development of T2D. In further support of this hypothesis is early pilot data suggesting that cortisol suppression failure occurs in obese children with impaired fasting glucose levels. The mechanism(s) underlying cortisol adaptive suppression, how and why these mechanism(s) fail are unknown. Elucidation of these mechanisms may lead to interventions to prevent the development of T2D and its complications in obese individuals.

Mechano-adaptation of the stem cell nucleus.

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Heo, Su-Jin; Cosgrove, Brian D; Dai, Eric N; Mauck, Robert L

2018-01-01

Exogenous mechanical forces are transmitted through the cell and to the nucleus, initiating mechanotransductive signaling cascades with profound effects on cellular function and stem cell fate. A growing body of evidence has shown that the force sensing and force-responsive elements of the nucleus adapt to these mechanotransductive events, tuning their response to future mechanical input. The mechanisms underlying this "mechano-adaptation" are only just beginning to be elucidated, and it remains poorly understood how these components act and adapt in tandem to drive stem cell differentiation. Here, we review the evidence on how the stem cell nucleus responds and adapts to physical forces, and provide a perspective on how this mechano-adaptation may function to drive and enforce stem cell differentiation.

Induction of a Radio-Adaptive Response by Low-dose Gamma Irradiation in Mouse Cardiomyocytes

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Westby, Christian M.; Seawright, John W.; Wu, Honglu

2011-01-01

One of the most significant occupational hazards to an astronaut is the frequent exposure to radiation. Commonly associated with increased risk for cancer related morbidity and mortality, radiation is also known to increase the risk for cardiovascular related disorders including: pericarditis, hypertension, and heart failure. It is believed that these radiation-induced disorders are a result of abnormal tissue remodeling. It is unknown whether radiation exposure promotes remodeling through fibrotic changes alone or in combination with programmed cell death. Furthermore, it is not known whether it is possible to mitigate the hazardous effects of radiation exposure. As such, we assessed the expression and mechanisms of radiation-induced tissue remodeling and potential radio-adaptive responses of p53-mediated apoptosis and fibrosis pathways along with markers for oxidative stress and inflammation in mice myocardium. 7 week old, male, C57Bl/6 mice were exposed to 6Gy (H) or 5cGy followed 24hr later with 6Gy (LH) 137Cs gamma radiation. Mice were sacrificed and their hearts extirpated 4, 24, or 72hr after final irradiation. Real Time - Polymerase Chain Reaction was used to evaluate target genes. Apoptotic genes Bad and Bax, pro-cell survival genes Bcl2 and Bcl2l2, fibrosis gene Vegfa, and oxidative stress genes Sod2 and GPx4 showed a reduced fold regulation change (Bad,-6.18; Bax,-6.94; Bcl2,-5.09; Bcl2l2,-4.03; Vegfa, -11.84; Sod2,-5.97; GPx4*,-28.72; * = Bonferroni adjusted p-value present compared to 24hr control. These data suggest a general reduction in genetic expression 4hrs after a high dose of gamma radiation. However, pre-exposure to 5cGy gamma radiation appears to facilitate a radio-adaptive response that mitigates the reduction in genetic expression associated with single high-dose gamma radiation exposure. This radio-adaptive response may serve as a potential countermeasure to radiation-induced myocardial remodeling and preserve the cardiovascular health of

Health effects of low-dose radiation: Molecular, cellular, and biosystem response

International Nuclear Information System (INIS)

Pollycove, M.; Paperiello, C.J.

1997-01-01

Since the fifties, the prime concern of radiation protection has been protecting DNA from damage. UNSCEAR initiated a focus on biosystem response to damage with its 1994 report, ''Adaptive Responses to Radiation of Cells and Organisms''. The DNA damage-control biosystem is physiologically operative on both metabolic and radiation induced damage, both effected predominantly by free radicals. These adaptive responses are suppressed by high-dose and stimulated by low dose radiation. Increased biosystem efficiently reduces the number of mutations that accumulate during a lifetime and decrease DNA damage-control with resultant aging and malignancy. Several statistically significant epidemiologic studies have shown risk decrements of cancer mortality and mortality from all causes in populations exposed to low-dose radiation. Further biologic and epidemiologic research is needed to establish a valid threshold below which risk decrements occur. (author)

Kruppel-like factor 15 is required for the cardiac adaptive response to fasting.

Science.gov (United States)

Sugi, Keiki; Hsieh, Paishiun N; Ilkayeva, Olga; Shelkay, Shamanthika; Moroney, Bridget; Baadh, Palvir; Haynes, Browning; Pophal, Megan; Fan, Liyan; Newgard, Christopher B; Prosdocimo, Domenick A; Jain, Mukesh K

2018-01-01

Cardiac metabolism is highly adaptive in response to changes in substrate availability, as occur during fasting. This metabolic flexibility is essential to the maintenance of contractile function and is under the control of a group of select transcriptional regulators, notably the nuclear receptor family of factors member PPARα. However, the diversity of physiologic and pathologic states through which the heart must sustain function suggests the possible existence of additional transcriptional regulators that play a role in matching cardiac metabolism to energetic demand. Here we show that cardiac KLF15 is required for the normal cardiac response to fasting. Specifically, we find that cardiac function is impaired upon fasting in systemic and cardiac specific Klf15-null mice. Further, cardiac specific Klf15-null mice display a fasting-dependent accumulation of long chain acylcarnitine species along with a decrease in expression of the carnitine translocase Slc25a20. Treatment with a diet high in short chain fatty acids relieves the KLF15-dependent long chain acylcarnitine accumulation and impaired cardiac function in response to fasting. Our observations establish KLF15 as a critical mediator of the cardiac adaptive response to fasting through its regulation of myocardial lipid utilization.

Evidence for adaptive evolution of low-temperature stress response genes in a Pooideae grass ancestor

DEFF Research Database (Denmark)

Vigeland, Magnus D; Spannagl, Manuel; Asp, Torben

2013-01-01

Adaptation to temperate environments is common in the grass subfamily Pooideae, suggesting an ancestral origin of cold climate adaptation. Here, we investigated substitution rates of genes involved in low-temperature-induced (LTI) stress responses to test the hypothesis that adaptive molecular...... evolution of LTI pathway genes was important for Pooideae evolution. Substitution rates and signatures of positive selection were analyzed using 4330 gene trees including three warm climate-adapted species (maize (Zea mays), sorghum (Sorghum bicolor), and rice (Oryza sativa)) and five temperate Pooideae...... species (Brachypodium distachyon, wheat (Triticum aestivum), barley (Hordeum vulgare), Lolium perenne and Festuca pratensis). Nonsynonymous substitution rate differences between Pooideae and warm habitat-adapted species were elevated in LTI trees compared with all trees. Furthermore, signatures...

Participation of intracellular signal transduction in the radio-adaptive response induced by low-dose X-irradiation in human embryonic cells

International Nuclear Information System (INIS)

Ishii, Keiichiro; Hoshi, Yuko; Iwasaki, Toshiyasu; Watanabe, Masami.

1996-01-01

To elucidate the induction mechanism of radio-adaptive response in normal cells, we searched the literatures of the intracellular signal transduction. Furthermore, we examined the induction of radio-adaptive response with or without inhibitors of several kinds of protein kinase. The major results obtained were as follows; (1) According to the literature survey it is revealed that there are 4 intracellular signal transduction pathways which are possibly involved in the induction of radio-adaptive response: pathways depending on cAMP, calcium, cGMP, or protein-tyrosine kinase. (2) Addition of either inhibitor of protein-tyrosine kinase or protein kinase C to the cell culture medium during the low-dose X-irradiation inhibited the induction of radio-adaptive response. However, the addition of inhibitor of cAMP-dependent protein kinase, cGMP-dependent protein kinase, or Ca 2+ -calmodulin kinase II failed to inhibit the induction of radio-adaptive response. (3) These results suggest that the signal induced in cells by low-dose X-irradiation was transduced from protein-tyrosine kinase to protein kinase C via either pathway of phosphatidylinositol 3-kinase or splitting of profilin binding phosphatidylinositol 4,5-bisphosphate. (author)

Adaptation of Listeria monocytogenes in a simulated cheese medium: effects on virulence using the Galleria mellonella infection model.

Science.gov (United States)

Schrama, D; Helliwell, N; Neto, L; Faleiro, M L

2013-06-01

The aim of this study was to evaluate the effect of the acid and salt adaptation in a cheese-based medium on the virulence potential of Listeria monocytogenes strains isolated from cheese and dairy processing environment using the Galleria mellonella model. Four L. monocytogenes strains were exposed to a cheese-based medium in conditions of induction of an acid tolerance response and osmotolerance response (pH 5·5 and 3·5% w/v NaCl) and injected in G. mellonella insects. The survival of insects and the L. monocytogenes growth kinetics in insects were evaluated. The gene expression of hly, actA and inlA genes was determined by real-time PCR. The adapted cells of two dairy strains showed reduced insect mortality (P 0·05) was found between adapted and nonadapted cells. The gene expression results evidenced an overexpression of virulence genes in cheese-based medium, but not in simulated insect-induced conditions. Our results suggest that adaptation to low pH and salt in a cheese-based medium can affect the virulence of L. monocytogenes, but this effect is strain dependent. In this study, the impact of adaptation to low pH and salt in a cheese-based medium on L. monocytogenes virulence was tested using the Wax Moth G. mellonella model. This model allowed the differentiation of the virulence potential between the L. monocytogenes strains. The effect of adaptation on virulence is strain dependent. The G. mellonella model revealed to be a prompt method to test food-related factors on L. monocytogenes virulence. © 2013 The Society for Applied Microbiology.

Psychological Adaptation to Extreme Environments: Effects of Team Composition on Individual Adaptation

Science.gov (United States)

Wood, J.; Hysong, S. J.; Lugg, D. J.; Harm, D. L.

1999-01-01

This study is part of an ongoing program of research examining the psychological effects of isolation and confinement on individual adaptation, productivity and group relations in Antarctic winter personnel. This environment is used as an analogue for long-duration space mission scenarios, such as a space station sojourn, or a mission to Mars. Earlier results from this and other environments have demonstrated that: (1) most changes in psychological well-being are event-related and of relatively short duration; and (2) the greatest problem facing most individuals is interpersonal conflict. Content analysis of responses to open-ended questions has identified the numerous enjoyable aspects of Antarctic living, and confirmed that many of the problems reported were interpersonal in nature, and that problems varied significantly by station. Current work is exploring the effects of team assignment on the self-reported psychological changes and self-evaluations of members of isolated teams. This work includes identifying the dimensions by which subjects determine how well they are functioning. These dimensions (e.g., work, social life, internal emotional state) appear to play an important role in how subjects evaluate many aspects of life in isolation.

Salinity Adaptation and the Contribution of Parental Environmental Effects in Medicago truncatula.

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Ken S Moriuchi

Full Text Available High soil salinity negatively influences plant growth and yield. Some taxa have evolved mechanisms for avoiding or tolerating elevated soil salinity, which can be modulated by the environment experienced by parents or offspring. We tested the contribution of the parental and offspring environments on salinity adaptation and their potential underlying mechanisms. In a two-generation greenhouse experiment, we factorially manipulated salinity concentrations for genotypes of Medicago truncatula that were originally collected from natural populations that differed in soil salinity. To compare population level adaptation to soil salinity and to test the potential mechanisms involved we measured two aspects of plant performance, reproduction and vegetative biomass, and phenological and physiological traits associated with salinity avoidance and tolerance. Saline-origin populations had greater biomass and reproduction under saline conditions than non-saline populations, consistent with local adaptation to saline soils. Additionally, parental environmental exposure to salt increased this difference in performance. In terms of environmental effects on mechanisms of salinity adaptation, parental exposure to salt spurred phenological differences that facilitated salt avoidance, while offspring exposure to salt resulted in traits associated with greater salt tolerance. Non-saline origin populations expressed traits associated with greater growth in the absence of salt while, for saline adapted populations, the ability to maintain greater performance in saline environments was also associated with lower growth potential in the absence of salt. Plastic responses induced by parental and offspring environments in phenology, leaf traits, and gas exchange contribute to salinity adaptation in M. truncatula. The ability of plants to tolerate environmental stress, such as high soil salinity, is likely modulated by a combination of parental effects and within

The congruency sequence effect 3.0: a critical test of conflict adaptation.

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Wout Duthoo

Full Text Available Over the last two decades, the congruency sequence effect (CSE -the finding of a reduced congruency effect following incongruent trials in conflict tasks- has played a central role in advancing research on cognitive control. According to the influential conflict-monitoring account, the CSE reflects adjustments in selective attention that enhance task focus when needed, often termed conflict adaptation. However, this dominant interpretation of the CSE has been called into question by several alternative accounts that stress the role of episodic memory processes: feature binding and (stimulus-response contingency learning. To evaluate the notion of conflict adaptation in accounting for the CSE, we construed versions of three widely used experimental paradigms (the colour-word Stroop, picture-word Stroop and flanker task that effectively control for feature binding and contingency learning. Results revealed that a CSE can emerge in all three tasks. This strongly suggests a contribution of attentional control to the CSE and highlights the potential of these unprecedentedly clean paradigms for further examining cognitive control.

Genetic evolution, plasticity, and bet-hedging as adaptive responses to temporally autocorrelated fluctuating selection: A quantitative genetic model.

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Tufto, Jarle

2015-08-01

Adaptive responses to autocorrelated environmental fluctuations through evolution in mean reaction norm elevation and slope and an independent component of the phenotypic variance are analyzed using a quantitative genetic model. Analytic approximations expressing the mutual dependencies between all three response modes are derived and solved for the joint evolutionary outcome. Both genetic evolution in reaction norm elevation and plasticity are favored by slow temporal fluctuations, with plasticity, in the absence of microenvironmental variability, being the dominant evolutionary outcome for reasonable parameter values. For fast fluctuations, tracking of the optimal phenotype through genetic evolution and plasticity is limited. If residual fluctuations in the optimal phenotype are large and stabilizing selection is strong, selection then acts to increase the phenotypic variance (bet-hedging adaptive). Otherwise, canalizing selection occurs. If the phenotypic variance increases with plasticity through the effect of microenvironmental variability, this shifts the joint evolutionary balance away from plasticity in favor of genetic evolution. If microenvironmental deviations experienced by each individual at the time of development and selection are correlated, however, more plasticity evolves. The adaptive significance of evolutionary fluctuations in plasticity and the phenotypic variance, transient evolution, and the validity of the analytic approximations are investigated using simulations. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Locomotor adaptability in persons with unilateral transtibial amputation.

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Darter, Benjamin J; Bastian, Amy J; Wolf, Erik J; Husson, Elizabeth M; Labrecque, Bethany A; Hendershot, Brad D

2017-01-01

Locomotor adaptation enables walkers to modify strategies when faced with challenging walking conditions. While a variety of neurological injuries can impair locomotor adaptability, the effect of a lower extremity amputation on adaptability is poorly understood. Determine if locomotor adaptability is impaired in persons with unilateral transtibial amputation (TTA). The locomotor adaptability of 10 persons with a TTA and 8 persons without an amputation was tested while walking on a split-belt treadmill with the parallel belts running at the same (tied) or different (split) speeds. In the split condition, participants walked for 15 minutes with the respective belts moving at 0.5 m/s and 1.5 m/s. Temporal spatial symmetry measures were used to evaluate reactive accommodations to the perturbation, and the adaptive/de-adaptive response. Persons with TTA and the reference group of persons without amputation both demonstrated highly symmetric walking at baseline. During the split adaptation and tied post-adaptation walking both groups responded with the expected reactive accommodations. Likewise, adaptive and de-adaptive responses were observed. The magnitude and rate of change in the adaptive and de-adaptive responses were similar for persons with TTA and those without an amputation. Furthermore, adaptability was no different based on belt assignment for the prosthetic limb during split adaptation walking. Reactive changes and locomotor adaptation in response to a challenging and novel walking condition were similar in persons with TTA to those without an amputation. Results suggest persons with TTA have the capacity to modify locomotor strategies to meet the demands of most walking conditions despite challenges imposed by an amputation and use of a prosthetic limb.

Critical concepts in adaptive clinical trials

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Park JJH

2018-03-01

Full Text Available Jay JH Park,1 Kristian Thorlund,2,3 Edward J Mills2,3 1Department of Medicine, University of British Columbia, Vancouver, BC, Canada; 2Department of Health Research Methods, Evidence, and Impact (HEI, McMaster University, Hamilton, ON, Canada; 3The Bill and Melinda Gates Foundation, Seattle, WA, USA Abstract: Adaptive clinical trials are an innovative trial design aimed at reducing resources, decreasing time to completion and number of patients exposed to inferior interventions, and improving the likelihood of detecting treatment effects. The last decade has seen an increasing use of adaptive designs, particularly in drug development. They frequently differ importantly from conventional clinical trials as they allow modifications to key trial design components during the trial, as data is being collected, using preplanned decision rules. Adaptive designs have increased likelihood of complexity and also potential bias, so it is important to understand the common types of adaptive designs. Many clinicians and investigators may be unfamiliar with the design considerations for adaptive designs. Given their complexities, adaptive trials require an understanding of design features and sources of bias. Herein, we introduce some common adaptive design elements and biases and specifically address response adaptive randomization, sample size reassessment, Bayesian methods for adaptive trials, seamless trials, and adaptive enrichment using real examples. Keywords: adaptive designs, response adaptive randomization, sample size reassessment, Bayesian adaptive trials, seamless trials, adaptive enrichment

Aberrant Pregnancy Adaptations in the Peripheral Immune Response in Type 1 Diabetes: A Rat Model.

Directory of Open Access Journals (Sweden)

Bart Groen

Full Text Available Despite tight glycemic control, pregnancy complication rate in type 1 diabetes patients is higher than in normal pregnancy. Other etiological factors may be responsible for the development of adverse pregnancy outcome. Acceptance of the semi-allogeneic fetus is accompanied by adaptations in the maternal immune-response. Maladaptations of the immune-response has been shown to contribute to pregnancy complications. We hypothesized that type 1 diabetes, as an autoimmune disease, may be associated with maladaptations of the immune-response to pregnancy, possibly resulting in pregnancy complications.We studied pregnancy outcome and pregnancy-induced immunological adaptations in a normoglycemic rat-model of type 1 diabetes, i.e. biobreeding diabetes-prone rats (BBDP; 5 non-pregnant rats, 7 pregnant day 10 rats and 6 pregnant day 18 rats , versus non-diabetic control rats (i.e. congenic non-diabetic biobreeding diabetes-resistant (BBDR; 6 non-pregnant rats, 6 pregnant day 10 rats and 6 pregnant day 18 rats and Wistar-rats (6 non-pregnant, 6 pregnant day 10 rats and 5 pregnant day 18 rats.We observed reduced litter size, lower fetal weight of viable fetuses and increased numbers of resorptions versus control rats. These complications are accompanied by various differences in the immune-response between BBDP and control rats in both pregnant and non-pregnant animals. The immune-response in non-pregnant BBDP-rats was characterized by decreased percentages of lymphocytes, increased percentages of effector T-cells, regulatory T-cells and natural killer cells, an increased Th1/Th2-ratio and activated monocytes versus Wistar and BBDR-rats. Furthermore, pregnancy-induced adaptations in BBDP-rats coincided with an increased Th1/Th2-ratio, a decreased mean fluorescence intensity CD161a/NKR-P1b ratio and no further activation of monocytes versus non-diabetic control rats.This study suggests that even in the face of strict normoglycemia, pregnancy complications

Prior acetaminophen consumption impacts the early adaptive cellular response of human skeletal muscle to resistance exercise.

Science.gov (United States)

D'Lugos, Andrew C; Patel, Shivam H; Ormsby, Jordan C; Curtis, Donald P; Fry, Christopher S; Carroll, Chad C; Dickinson, Jared M

2018-04-01

Resistance exercise (RE) is a powerful stimulus for skeletal muscle adaptation. Previous data demonstrate that cyclooxygenase (COX)-inhibiting drugs alter the cellular mechanisms regulating the adaptive response of skeletal muscle. The purpose of this study was to determine whether prior consumption of the COX inhibitor acetaminophen (APAP) alters the immediate adaptive cellular response in human skeletal muscle after RE. In a double-blinded, randomized, crossover design, healthy young men ( n = 8, 25 ± 1 yr) performed two trials of unilateral knee extension RE (8 sets, 10 reps, 65% max strength). Subjects ingested either APAP (1,000 mg/6 h) or placebo (PLA) for 24 h before RE (final dose consumed immediately after RE). Muscle biopsies (vastus lateralis) were collected at rest and 1 h and 3 h after exercise. Mammalian target of rapamycin (mTOR) complex 1 signaling was assessed through immunoblot and immunohistochemistry, and mRNA expression of myogenic genes was examined via RT-qPCR. At 1 h p-rpS6 Ser240/244 was increased in both groups but to a greater extent in PLA. At 3 h p-S6K1 Thr389 was elevated only in PLA. Furthermore, localization of mTOR to the lysosome (LAMP2) in myosin heavy chain (MHC) II fibers increased 3 h after exercise only in PLA. mTOR-LAMP2 colocalization in MHC I fibers was greater in PLA vs. APAP 1 h after exercise. Myostatin mRNA expression was reduced 1 h after exercise only in PLA. MYF6 mRNA expression was increased 1 h and 3 h after exercise only in APAP. APAP consumption appears to alter the early adaptive cellular response of skeletal muscle to RE. These findings further highlight the mechanisms through which COX-inhibiting drugs impact the adaptive response of skeletal muscle to exercise. NEW & NOTEWORTHY The extent to which the cellular reaction to acetaminophen impacts the mechanisms regulating the adaptive response of human skeletal muscle to resistance exercise is not well understood. Consumption of acetaminophen before

Robust synchronization of drive-response chaotic systems via adaptive sliding mode control

International Nuclear Information System (INIS)

Li, W.-L.; Chang, K.-M.

2009-01-01

A robust adaptive sliding control scheme is developed in this study to achieve synchronization for two identical chaotic systems in the presence of uncertain system parameters, external disturbances and nonlinear control inputs. An adaptation algorithm is given based on the Lyapunov stability theory. Using this adaptation technique to estimate the upper-bounds of parameter variation and external disturbance uncertainties, an adaptive sliding mode controller is then constructed without requiring the bounds of parameter and disturbance uncertainties to be known in advance. It is proven that the proposed adaptive sliding mode controller can maintain the existence of sliding mode in finite time in uncertain chaotic systems. Finally, numerical simulations are presented to show the effectiveness of the proposed control scheme.

Adaptive response in Drosophila melanogaster heat shock proteins mutant strains

International Nuclear Information System (INIS)

Shaposhnikov, M.V.; Moskalev, A.A.; Turysheva, E.V.

2007-01-01

Complete text of publication follows. The members of the heat shock proteins (Hsp) family function as molecular chaperones and assist intracellular folding of newly synthesized proteins. Also it is possible that molecular chaperones are induced during adaptive response to oxidative stress and radiation. The aim of our research was to exam the role of heat shock proteins in adaptive response to oxidative stress after low dose rate gamma-irradiation in Drosophila melanogaster. Drosophilamelanogaster strains were kindly provided by Bloomington Drosophila Stock Center (University of state of Indiana, Bloomington, USA). We used wild type strain (CS), heat shock protein mutant strains (Hsp22, Hsp70, Hsp83), and heat shock factor mutant strain (Hsf). Strains were chronically exposured to adaptive dose of gamma-irradiation in dose rate of 0.17 cGy/h during all stages of life history (from the embrional stage to the stage of matured imago). The rate of absorbed dose was 60 cGy. For oxidative-stress challenge twodays old flies were starved in empty vials for 6 h and then transferred to vials containing only filter paper soaked with 20 mM paraquat in 5% sucrose solution. Survival data were collected after 26 h of treatment. Dead flies were counted daily. The obtained data were subjected to survival analysis by Kaplan and Meier method and presented as survival curves. Statistical analysis was held by non-parametric methods. To test the significance of the difference between the two age distributions Kolmogorov-Smirnov test was applied. Gehan-Braslow- Wilcoxon and Cox-Mantel tests were used for estimation of median life span differences. In addition the minimal and maximal life span, time of 90% death, and mortality rate doubling time (MRDT) were estimated. The obtained results will be discussed in presentation.

Occupants' adaptive responses and perception of thermal environment in naturally conditioned university classrooms

Energy Technology Data Exchange (ETDEWEB)

Yao, Runming [The School of Construction Management and Engineering, The University of Reading, Whiteknights, PO Box 219, Reading RG6 6AW (United Kingdom); The Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400042 (China); Liu, Jing [The School of Construction Management and Engineering, The University of Reading, Whiteknights, PO Box 219, Reading RG6 6AW (United Kingdom); Li, Baizhan [The Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400042 (China); Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environment (Ministry of Education), Chongqing University, Chongqing 400042 (China)

2010-03-15

A year-long field study of the thermal environment in university classrooms was conducted from March 2005 to May 2006 in Chongqing, China. This paper presents the occupants' thermal sensation votes and discusses the occupants' adaptive response and perception of the thermal environment in a naturally conditioned space. Comparisons between the Actual Mean Vote (AMV) and Predicted Mean Vote (PMV) have been made as well as between the Actual Percentage of Dissatisfied (APD) and Predicted Percentage of Dissatisfied (PPD). The adaptive thermal comfort zone for the naturally conditioned space for Chongqing, which has hot summer and cold winter climatic characteristics, has been proposed based on the field study results. The Chongqing adaptive comfort range is broader than that of the ASHRAE Standard 55-2004 in general, but in the extreme cold and hot months, it is narrower. The thermal conditions in classrooms in Chongqing in summer and winter are severe. Behavioural adaptation such as changing clothing, adjusting indoor air velocity, taking hot/cold drinks, etc., as well as psychological adaptation, has played a role in adapting to the thermal environment. (author)

Reconceptualising adaptation to climate change as part of pathways of change and response

CSIR Research Space (South Africa)

Wise, RM

2014-01-01

Full Text Available on contexts with clearly identified decision-makers and unambiguous goals; as a result, they generally assume prevailing governance regimes are conducive for adaptation and hence constrain responses to proximate causes of vulnerability. In this paper, we...

SU-D-BRB-05: Quantum Learning for Knowledge-Based Response-Adaptive Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

El Naqa, I; Ten, R [Haken University of Michigan, Ann Arbor, MI (United States)

2016-06-15

Purpose: There is tremendous excitement in radiotherapy about applying data-driven methods to develop personalized clinical decisions for real-time response-based adaptation. However, classical statistical learning methods lack in terms of efficiency and ability to predict outcomes under conditions of uncertainty and incomplete information. Therefore, we are investigating physics-inspired machine learning approaches by utilizing quantum principles for developing a robust framework to dynamically adapt treatments to individual patient’s characteristics and optimize outcomes. Methods: We studied 88 liver SBRT patients with 35 on non-adaptive and 53 on adaptive protocols. Adaptation was based on liver function using a split-course of 3+2 fractions with a month break. The radiotherapy environment was modeled as a Markov decision process (MDP) of baseline and one month into treatment states. The patient environment was modeled by a 5-variable state represented by patient’s clinical and dosimetric covariates. For comparison of classical and quantum learning methods, decision-making to adapt at one month was considered. The MDP objective was defined by the complication-free tumor control (P{sup +}=TCPx(1-NTCP)). A simple regression model represented state-action mapping. Single bit in classical MDP and a qubit of 2-superimposed states in quantum MDP represented the decision actions. Classical decision selection was done using reinforcement Q-learning and quantum searching was performed using Grover’s algorithm, which applies uniform superposition over possible states and yields quadratic speed-up. Results: Classical/quantum MDPs suggested adaptation (probability amplitude ≥0.5) 79% of the time for splitcourses and 100% for continuous-courses. However, the classical MDP had an average adaptation probability of 0.5±0.22 while the quantum algorithm reached 0.76±0.28. In cases where adaptation failed, classical MDP yielded 0.31±0.26 average amplitude while the

Adaptive sequential controller

Energy Technology Data Exchange (ETDEWEB)

El-Sharkawi, Mohamed A. (Renton, WA); Xing, Jian (Seattle, WA); Butler, Nicholas G. (Newberg, OR); Rodriguez, Alonso (Pasadena, CA)

1994-01-01

An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.

Adaptive sequential controller

Science.gov (United States)

El-Sharkawi, Mohamed A.; Xing, Jian; Butler, Nicholas G.; Rodriguez, Alonso

1994-01-01

An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.

Muscle Plasticity and β2-Adrenergic Receptors: Adaptive Responses of β2-Adrenergic Receptor Expression to Muscle Hypertrophy and Atrophy

OpenAIRE

Shogo Sato; Ken Shirato; Kaoru Tachiyashiki; Kazuhiko Imaizumi

2011-01-01

We discuss the functional roles of β2-adrenergic receptors in skeletal muscle hypertrophy and atrophy as well as the adaptive responses of β2-adrenergic receptor expression to anabolic and catabolic conditions. β2-Adrenergic receptor stimulation using anabolic drugs increases muscle mass by promoting muscle protein synthesis and/or attenuating protein degradation. These effects are prevented ...

A comparison of item response models for accuracy and speed of item responses with applications to adaptive testing.

Science.gov (United States)

van Rijn, Peter W; Ali, Usama S

2017-05-01

We compare three modelling frameworks for accuracy and speed of item responses in the context of adaptive testing. The first framework is based on modelling scores that result from a scoring rule that incorporates both accuracy and speed. The second framework is the hierarchical modelling approach developed by van der Linden (2007, Psychometrika, 72, 287) in which a regular item response model is specified for accuracy and a log-normal model for speed. The third framework is the diffusion framework in which the response is assumed to be the result of a Wiener process. Although the three frameworks differ in the relation between accuracy and speed, one commonality is that the marginal model for accuracy can be simplified to the two-parameter logistic model. We discuss both conditional and marginal estimation of model parameters. Models from all three frameworks were fitted to data from a mathematics and spelling test. Furthermore, we applied a linear and adaptive testing mode to the data off-line in order to determine differences between modelling frameworks. It was found that a model from the scoring rule framework outperformed a hierarchical model in terms of model-based reliability, but the results were mixed with respect to correlations with external measures. © 2017 The British Psychological Society.

Creative tensions: mutual responsiveness adapted to private sector research and development.

Science.gov (United States)

Sonck, Matti; Asveld, Lotte; Landeweerd, Laurens; Osseweijer, Patricia

2017-09-07

The concept of mutual responsiveness is currently based on little empirical data in the literature of Responsible Research and Innovation (RRI). This paper explores RRI's idea of mutual responsiveness in the light of recent RRI case studies on private sector research and development (R&D). In RRI, responsible innovation is understood as a joint endeavour of innovators and societal stakeholders, who become mutually responsive to each other in defining the 'right impacts' of the innovation in society, and in steering the innovation towards realising those impacts. Yet, the case studies identified several reasons for why the idea of mutual responsiveness does not always appear feasible or desirable in actual R&D situations. Inspired by the discrepancies between theory and practice, we suggest three further elaborations for the concept of responsiveness in RRI. Process-responsiveness is suggested for identifying situations that require stakeholder involvement specifically during R&D. Product-responsiveness is suggested for mobilising the potential of innovation products to be adaptable according to diverse stakeholder needs. Presponsiveness is suggested as responsiveness towards stakeholders that are not (yet) reachable at a given time of R&D. Our aim is to contribute to a more tangible understanding of responsiveness in RRI, and suggest directions for further analysis in upcoming RRI case studies.

Effects of the amount and schedule of varied practice after constant practice on the adaptive process of motor learning

Directory of Open Access Journals (Sweden)

Umberto Cesar Corrêa

2014-12-01

Full Text Available This study investigated the effects of different amounts and schedules of varied practice, after constant practice, on the adaptive process of motor learning. Participants were one hundred and seven children with a mean age of 11.1 ± 0.9 years. Three experiments were carried out using a complex anticipatory timing task manipulating the following components in the varied practice: visual stimulus speed (experiment 1; sequential response pattern (experiment 2; and visual stimulus speed plus sequential response pattern (experiment 3. In all experiments the design involved three amounts (18, 36, and 63 trials, and two schedules (random and blocked of varied practice. The experiments also involved two learning phases: stabilization and adaptation. The dependent variables were the absolute, variable, and constant errors related to the task goal, and the relative timing of the sequential response. Results showed that all groups worsened the performances in the adaptation phase, and no difference was observed between them. Altogether, the results of the three experiments allow the conclusion that the amounts of trials manipulated in the random and blocked practices did not promote the diversification of the skill since no adaptation was observed.

Adaptive evolution of body size subject to indirect effect in trophic cascade system.

Science.gov (United States)

Wang, Xin; Fan, Meng; Hao, Lina

2017-09-01

Trophic cascades represent a classic example of indirect effect and are wide-spread in nature. Their ecological impact are well established, but the evolutionary consequences have received even less theoretical attention. We theoretically and numerically investigate the trait (i.e., body size of consumer) evolution in response to indirect effect in a trophic cascade system. By applying the quantitative trait evolutionary theory and the adaptive dynamic theory, we formulate and explore two different types of eco-evolutionary resource-consumer-predator trophic cascade model. First, an eco-evolutionary model incorporating the rapid evolution is formulated to investigate the effect of rapid evolution of the consumer's body size, and to explore the impact of density-mediate indirect effect on the population dynamics and trait dynamics. Next, by employing the adaptive dynamic theory, a long-term evolutionary model of consumer body size is formulated to evaluate the effect of long-term evolution on the population dynamics and the effect of trait-mediate indirect effect. Those models admit rich dynamics that has not been observed yet in empirical studies. It is found that, both in the trait-mediated and density-mediated system, the body size of consumer in predator-consumer-resource interaction (indirect effect) evolves smaller than that in consumer-resource and predator-consumer interaction (direct effect). Moreover, in the density-mediated system, we found that the evolution of consumer body size contributes to avoiding consumer extinction (i.e., evolutionary rescue). The trait-mediate and density-mediate effects may produce opposite evolutionary response. This study suggests that the trophic cascade indirect effect affects consumer evolution, highlights a more comprehensive mechanistic understanding of the intricate interplay between ecological and evolutionary force. The modeling approaches provide avenue for study on indirect effects from an evolutionary perspective

Haemodynamic responses and changes of haemostatic risk factors in cold-adapted humans.

Science.gov (United States)

De Lorenzo, F; Kadziola, Z; Mukherjee, M; Saba, N; Kakkar, V V

1999-09-01

Epidemiological studies have shown an increase in acute myocardial infarctions or deaths due to myocardial infarction in colder weather; the mechanisms most likely involve increased blood levels of haemostatic risk factors, and increases in arterial blood pressure and heart rate. We studied the relationship between cold adaptation, haemostatic risk factors and haemodynamic variables. Cold adaptation was obtained by a programme of immersion of the whole body up to the neck in a water-filled bath, the temperature of which was gradually decreased from 22 degrees C to 14 degrees C, time of exposure being increased from 5 to 20 min over a period of 90 days. We studied 428 patients (44% men) and measured blood levels of fibrinogen, plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator antigen (t-PA), plasma viscosity, von Willebrand factor, D-dimer and platelet count, both at baseline and after 90 days of daily immersion. There were significant reductions in von Willebrand factor (-3%; p cold adaptation (-310; p = 0.004). Cold adaptation, compared with exposure to cold weather, induces different haemodynamic responses and changes of blood levels of haemostatic risk factors.

Dynamical adaptation in photoreceptors.

Directory of Open Access Journals (Sweden)

Damon A Clark

Full Text Available Adaptation is at the heart of sensation and nowhere is it more salient than in early visual processing. Light adaptation in photoreceptors is doubly dynamical: it depends upon the temporal structure of the input and it affects the temporal structure of the response. We introduce a non-linear dynamical adaptation model of photoreceptors. It is simple enough that it can be solved exactly and simulated with ease; analytical and numerical approaches combined provide both intuition on the behavior of dynamical adaptation and quantitative results to be compared with data. Yet the model is rich enough to capture intricate phenomenology. First, we show that it reproduces the known phenomenology of light response and short-term adaptation. Second, we present new recordings and demonstrate that the model reproduces cone response with great precision. Third, we derive a number of predictions on the response of photoreceptors to sophisticated stimuli such as periodic inputs, various forms of flickering inputs, and natural inputs. In particular, we demonstrate that photoreceptors undergo rapid adaptation of response gain and time scale, over ∼ 300[Formula: see text] ms-i. e., over the time scale of the response itself-and we confirm this prediction with data. For natural inputs, this fast adaptation can modulate the response gain more than tenfold and is hence physiologically relevant.

Interferon alpha inhibits replication of a live-attenuated porcine reproductive and respiratory syndrome virus vaccine preventing development of an adaptive immune response in swine.

Science.gov (United States)

Brockmeier, Susan L; Loving, Crystal L; Eberle, Kirsten C; Hau, Samantha J; Buckley, Alexandra; Van Geelen, Albert; Montiel, Nestor A; Nicholson, Tracy; Lager, Kelly M

2017-12-01

Type I interferons, such as interferon alpha (IFN-α), contribute to innate antiviral immunity by promoting production of antiviral mediators and are also involved in promoting an adaptive immune response. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most devastating and costly viruses to the swine industry world-wide and has been shown to induce a meager IFN-α response. Previously we administered porcine IFN-α using a replication-defective adenovirus vector (Ad5-IFN-α) at the time of challenge with virulent PRRSV and demonstrated an increase in the number of virus-specific IFNγ secreting cells, indicating that the presence of IFN-α at the time of infection can alter the adaptive immune responses to PRRSV. In the current experiment, we explored the use of IFN-α as an adjuvant administered with live-attenuated PRRSV vaccine as a method to enhance immune response to the vaccine. Unlike the previous studies with fully virulent virus, one injection of the Ad5-IFN-α abolished replication of the vaccine virus and as a result there was no detectible adaptive immune response. Although IFN-α did not have the desired adjuvant effect, the results further highlight the use of IFN-α as a treatment for PRRSV infection. Published by Elsevier B.V.

Preliminary Efficacy of Adapted Responsive Teaching for Infants at Risk of Autism Spectrum Disorder in a Community Sample

Directory of Open Access Journals (Sweden)

Grace T. Baranek

2015-01-01

Full Text Available This study examined the (a feasibility of enrolling 12-month-olds at risk of ASD from a community sample into a randomized controlled trial, (b subsequent utilization of community services, and (c potential of a novel parent-mediated intervention to improve outcomes. The First Year Inventory was used to screen and recruit 12-month-old infants at risk of ASD to compare the effects of 6–9 months of Adapted Responsive Teaching (ART versus referral to early intervention and monitoring (REIM. Eighteen families were followed for ~20 months. Assessments were conducted before randomization, after treatment, and at 6-month follow-up. Utilization of community services was highest for the REIM group. ART significantly outperformed REIM on parent-reported and observed measures of child receptive language with good linear model fit. Multiphase growth models had better fit for more variables, showing the greatest effects in the active treatment phase, where ART outperformed REIM on parental interactive style (less directive, child sensory responsiveness (less hyporesponsive, and adaptive behavior (increased communication and socialization. This study demonstrates the promise of a parent-mediated intervention for improving developmental outcomes for infants at risk of ASD in a community sample and highlights the utility of earlier identification for access to community services earlier than standard practice.

Spontaneous recovery of effects of contrast adaptation without awareness

Directory of Open Access Journals (Sweden)

Gaoxing eMei

2015-09-01

Full Text Available Prolonged exposure to a high contrast stimulus reduces the neural sensitivity to subsequent similar patterns. Recent work has disclosed that contrast adaptation is controlled by multiple mechanisms operating over differing timescales. Adaptation to high contrast for a relatively longer period can be rapidly eliminated by adaptation to a lower contrast (or meanfield in the present study. Such rapid deadaptation presumably causes a short-term mechanism to signal for a sensitivity increase, cancelling ongoing signals from long-term mechanisms. Once deadaptation ends, the short-term mechanism rapidly returns to baseline, and the slowly decaying effects in the long-term mechanisms reemerge, allowing the perceptual aftereffects to recover during continued testing. Although this spontaneous recovery effect is considered strong evidence supporting the multiple mechanisms theory, it remains controversial whether the effect is mainly driven by visual memory established during the initial longer-term adaptation period. To resolve this debate, we used a modified Continuous Flash Suppression (CFS and visual crowding paradigms to render the adapting stimuli invisible, but still observed the spontaneous recovery phenomenon. These results exclude the possibility that spontaneous recovery found in the previous work was merely the consequence of explicit visual memory. Our findings also demonstrate that contrast adaptation, even at the unconscious processing levels, is controlled by multiple mechanisms.

The comparison of the intestinal adaptation effects of subcutaneous ...

African Journals Online (AJOL)

Aim: Insulin has been reported to have positive effects on intestinal adaptation after short bowel syndrome when applicated oral or subcutaneously. The purpose of this study is to compare the intestinal adaptation effects of subcutaneous and oral routes of insulin in rats with short bowel syndrome. Materials and Methods: ...

Investigation of the response of low-dose irradiated cells. Pt. 2. Radio-adaptive response of human embryonic cells is related to cell-to-cell communication

International Nuclear Information System (INIS)

Ishii, Keiichiro; Watanabe, Masami.

1994-01-01

To clarify the radio-adaptive response of normal cells to low-dose radiation, we irradiated human embryonic cells and HeLa cells with low-dose X-ray and examined the changes in sensitivity to subsequent high-dose X-irradiation. The results obtained were as follows; (1) When HE cells were irradiated by a high-dose of 200 cGy, the growth ratio of the living cells five days after the irradiation decreased to 37% of that of the cells which received no X-irradiation. When the cells received a preliminary irradiation of 10 to 20 cGy four hours before the irradiation of 200 cGy, the relative growth ratios increased significantly to 45-53%. (2) This preliminary irradiation effect was not observed in HeLa cells, being cancer cells. (3) When the HE cells suspended in a Ca 2+ iron-free medium or TPA added medium while receiving the preliminary irradiation of 13 cGy, the effect of the preliminary irradiation in increasing the relative growth ratio of living cells was not observed. (4) This indicates that normal cells shows an adaptive response to low-dose radiation and become more radioresistant. This phenomenon is considered to involve cell-to-cell communication maintained in normal cells and intracellular signal transduction in which Ca 2+ ion plays a role. (author)

Training Modalities to Increase Sensorimotor Adaptability

Science.gov (United States)

Bloomberg, J. J.; Mulavara, A. P.; Peters, B. T.; Brady, R.; Audas, C.; Cohen, H. S.

2009-01-01

During the acute phase of adaptation to novel gravitational environments, sensorimotor disturbances have the potential to disrupt the ability of astronauts to perform required mission tasks. The goal of our current series of studies is develop a sensorimotor adaptability (SA) training program designed to facilitate recovery of functional capabilities when astronauts transition to different gravitational environments. The project has conducted a series of studies investigating the efficacy of treadmill training combined with a variety of sensory challenges (incongruent visual input, support surface instability) designed to increase adaptability. SA training using a treadmill combined with exposure to altered visual input was effective in producing increased adaptability in a more complex over-ground ambulatory task on an obstacle course. This confirms that for a complex task like walking, treadmill training contains enough of the critical features of overground walking to be an effective training modality. SA training can be optimized by using a periodized training schedule. Test sessions that each contain short-duration exposures to multiple perturbation stimuli allows subjects to acquire a greater ability to rapidly reorganize appropriate response strategies when encountering a novel sensory environment. Using a treadmill mounted on top of a six degree-of-freedom motion base platform we investigated locomotor training responses produced by subjects introduced to a dynamic walking surface combined with alterations in visual flow. Subjects who received this training had improved locomotor performance and faster reaction times when exposed to the novel sensory stimuli compared to control subjects. Results also demonstrate that individual sensory biases (i.e. increased visual dependency) can predict adaptive responses to novel sensory environments suggesting that individual training prescription can be developed to enhance adaptability. These data indicate that SA

Biodiversity and global change. Adaptative responses to global change: results and prospective. IFB-GICC restitution colloquium

International Nuclear Information System (INIS)

Despres, L.; Hossaert-Mckey, M.; Martin, J.F.; Pont, D.; Valero, M.; Chave, J.; Benizri, E.; Amiaud, B.; Boury-Esnault, N.; Fritz, H.; Lavelle, P.; Martin, F.; Poulet, S.; Blanchard, F.; Cheddadi, R.; Dupouey, J.L.; Hulle, M.; Michaux, J.; Souissi, S.; Bridault, A.; Dambrine, E.; Gomez, B.; Thevenard, F.; Legendre, S.; Suc, J.P.; Zeitoun, V.; Bezancon, G.; Frascaria-Lacoste, N.; Ponsard, S.; Bourguet, D.; Vigne, J.D.; Doyen, L.; Joly, P.; Gourlet-Fleury, S.; Garnier, E.; Lebaron, Ph.; Boulinier, Th.; Chuine, I.; Jiguet, F.; Couvet, D.; Soussana, J.F.; Weimerskirsch, H.; Grosbois, V.; Bretagnolle, V.

2006-01-01

Global change is the consequence of the worldwide human print on ecology. The uncontrolled use of fossil fuels, the urbanization, the intensifying of agriculture, the homogenization of life styles and cultures, the homogenization of fauna and vegetation, the commercial trades, the bio-invasions, the over-exploitation of resources and the emergence of new economic powers (China, India, Brazil..) represent an adaptative dynamics of interactions which affects the overall biosphere and the adaptative capacities and the future of all species. Biodiversity is an ecological and societal insurance against the risks and uncertainties linked with global change. The French institute of biodiversity (IFB) has created a working group in charge of a study on global change and biodiversity, in particular in terms of: speed and acceleration of processes, interaction between the different organization levels of the world of living, scale changes, and adaptative capacities. 38 projects with an interdisciplinary approach have been retained by the IFB and the Ministry of ecology and sustainable development. The conclusion of these projects were presented at this restitution colloquium and are summarized in this document. The presentations are organized in 7 sessions dealing with: global changes and adaptation mechanisms; functional responses to global changes; spatial responses to global changes; temporal responses to global changes; selective answers to global changes; available tools and ecological services; scenarios and projections. (J.S.)

Homeland security and virtual reality: building a Strategic Adaptive Response System (STARS).

Science.gov (United States)

Swift, Christopher; Rosen, Joseph M; Boezer, Gordon; Lanier, Jaron; Henderson, Joseph V; Liu, Alan; Merrell, Ronald C; Nguyen, Sinh; Demas, Alex; Grigg, Elliot B; McKnight, Matthew F; Chang, Janelle; Koop, C Everett

2005-01-01

The advent of the Global War on Terrorism (GWOT) underscored the need to improve the U.S. disaster response paradigm. Existing systems involve numerous agencies spread across disparate functional and geographic jurisdictions. The current architecture remains vulnerable to sophisticated terrorist strikes. To address these vulnerabilities, we must continuously adapt and improve our Homeland Security architecture. Virtual Reality (VR) technologies will help model those changes and integrate technologies. This paper provides a broad overview of the strategic threats, together with a detailed examination of how specific VR technologies could be used to ensure successful disaster responses.

Thermotolerant yeasts selected by adaptive evolution express heat stress response at 30ºC

DEFF Research Database (Denmark)

Caspeta, Luis; Chen, Yun; Nielsen, Jens

2016-01-01

to grow at increased temperature, activated a constitutive heat stress response when grown at the optimal ancestral temperature, and that this is associated with a reduced growth rate. This preventive response was perfected by additional transcriptional changes activated when the cultivation temperature...... is increased. Remarkably, the sum of global transcriptional changes activated in the thermotolerant strains when transferred from the optimal to the high temperature, corresponded, in magnitude and direction, to the global changes observed in the ancestral strain exposed to the same transition....... This demonstrates robustness of the yeast transcriptional program when exposed to heat, and that the thermotolerant strains streamlined their path to rapidly and optimally reach post-stress transcriptional and metabolic levels. Thus, long-term adaptation to heat improved yeasts ability to rapidly adapt to increased...

Degree of adaptive response in urban tolerant birds shows influence of habitat-of-origin

Directory of Open Access Journals (Sweden)

Lawrence E. Conole

2014-03-01

Full Text Available Urban exploiters and adapters are often coalesced under a term of convenience as ‘urban tolerant’. This useful but simplistic characterisation masks a more nuanced interplay between and within assemblages of birds that are more or less well adapted to a range of urban habitats. I test the hypotheses that objectively-defined urban exploiter and suburban adapter assemblages within the broad urban tolerant grouping in Melbourne vary in their responses within the larger group to predictor variables, and that the most explanatory predictor variables vary between the two assemblages. A paired, partitioned analysis of exploiter and adapter preferences for points along the urban–rural gradient was undertaken to decompose the overall trend into diagnosable parts for each assemblage. In a similar way to that in which time since establishment has been found to be related to high urban densities of some bird species and biogeographic origin predictive of urban adaptation extent, habitat origins of members of bird assemblages influence the degree to which they become urban tolerant. Bird species that objectively classify as urban tolerant will further classify as either exploiters or adapters according to the degree of openness of their habitats-of-origin.

Scientists in a Changed Institutional Environment: Subjective Adaptation and Social Responsibility Norms in Russia

Energy Technology Data Exchange (ETDEWEB)

Gerber, T P; Ball, D Y

2008-06-05

How do scientists react when the institutional setting in which they conduct their work changes radically? How do long-standing norms regarding the social responsibility of scientists fare? What factors influence whether scientists embrace or reject the new institutions and norms? We examine these questions using data from a unique survey of 602 scientists in Russia, whose science system experienced a sustained crisis and sweeping changes in science institutions following the collapse of the Soviet Union. We develop measures of how respondents view financing based on grants and other institutional changes in the Russian science system, as well as measures of two norms regarding scientists social responsibility. We find that the majority of scientists have adapted, in the sense that they hold positive views of the new institutions, but a diversity of orientations remains. Social responsibility norms are common among Russian scientists, but far from universal. The main correlates of adaptation are age and current success at negotiating the new institutions, though prospective success, work context, and ethnicity have some of the hypothesized associations. As for social responsibility norms, the main source of variation is age: younger scientists are more likely to embrace individualistic rather than socially-oriented norms.

Adaptive and Pathogenic Responses to Stress by Stem Cells during Development

OpenAIRE

Mansouri, Ladan; Xie, Yufen; Rappolee, Daniel A

2012-01-01

Cellular stress is the basis of a dose-dependent continuum of responses leading to adaptive health or pathogenesis. For all cells, stress leads to reduction in macromolecular synthesis by shared pathways and tissue and stress-specific homeostatic mechanisms. For stem cells during embryonic, fetal, and placental development, higher exposures of stress lead to decreased anabolism, macromolecular synthesis and cell proliferation. Coupled with diminished stem cell proliferation is a stress-induce...

Focused cognitive control in dishonesty: Evidence for predominantly transient conflict adaptation.

Science.gov (United States)

Foerster, Anna; Pfister, Roland; Schmidts, Constantin; Dignath, David; Wirth, Robert; Kunde, Wilfried

2018-04-01

Giving a dishonest response to a question entails cognitive conflict due to an initial activation of the truthful response. Following conflict monitoring theory, dishonest responding could therefore elicit transient and sustained control adaptation processes to mitigate such conflict, and the current experiments take on the scope and specificity of such conflict adaptation in dishonesty. Transient adaptation reduces differences between honest and dishonest responding following a recent dishonest response. Sustained adaptation has a similar behavioral signature but is driven by the overall frequency of dishonest responding. Both types of adaptation to recent and frequent dishonest responses have been separately documented, leaving open whether control processes in dishonest responding can flexibly adapt to transient and sustained conflict signals of dishonest and other actions. This was the goal of the present experiments which studied (dis)honest responding to autobiographical yes/no questions. Experiment 1 showed robust transient adaptation to recent dishonest responses whereas sustained control adaptation failed to exert an influence on behavior. It further revealed that transient effects may create a spurious impression of sustained adaptation in typical experimental settings. Experiments 2 and 3 examined whether dishonest responding can profit from transient and sustained adaption processes triggered by other behavioral conflicts. This was clearly not the case: Dishonest responding adapted markedly to recent (dis)honest responses but not to any context of other conflicts. These findings indicate that control adaptation in dishonest responding is strong but surprisingly focused and they point to a potential trade-off between transient and sustained adaptation. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Adaptive Detection and ISI Mitigation for Mobile Molecular Communication.

Science.gov (United States)

Chang, Ge; Lin, Lin; Yan, Hao

2018-03-01

Current studies on modulation and detection schemes in molecular communication mainly focus on the scenarios with static transmitters and receivers. However, mobile molecular communication is needed in many envisioned applications, such as target tracking and drug delivery. Until now, investigations about mobile molecular communication have been limited. In this paper, a static transmitter and a mobile bacterium-based receiver performing random walk are considered. In this mobile scenario, the channel impulse response changes due to the dynamic change of the distance between the transmitter and the receiver. Detection schemes based on fixed distance fail in signal detection in such a scenario. Furthermore, the intersymbol interference (ISI) effect becomes more complex due to the dynamic character of the signal which makes the estimation and mitigation of the ISI even more difficult. In this paper, an adaptive ISI mitigation method and two adaptive detection schemes are proposed for this mobile scenario. In the proposed scheme, adaptive ISI mitigation, estimation of dynamic distance, and the corresponding impulse response reconstruction are performed in each symbol interval. Based on the dynamic channel impulse response in each interval, two adaptive detection schemes, concentration-based adaptive threshold detection and peak-time-based adaptive detection, are proposed for signal detection. Simulations demonstrate that the ISI effect is significantly reduced and the adaptive detection schemes are reliable and robust for mobile molecular communication.

Phenotypic plasticity as an adaptive response to predictable and unpredictable environmental changes

DEFF Research Database (Denmark)

Manenti, Tommaso

Phenotypic plasticity is the ability of a genotype to modify its phenotype in response to environmental changes as a consequence of an interaction between genes and environment (Bradshaw, 1965). Plasticity contributes to the vast phenotypic variation observed in natural populations. Many examples...... of a plastic response are expected to depend on the environmental conditions experienced by organisms. Thus, in populations exposed to a non-changing environment, the plastic machinery might be a waste of resources. Contrary, in populations experiencing varying environmental conditions, plasticity is expected...... such as anti-predator behaviours or the activation of mechanisms to prevent thermal stress injuries suggest that plasticity is an adaptive response, favoured by natural selection. At the same time, organisms do show limited plastic responses, indicating that this ability is not for free. Costs and benefits...

Conflict adaptation and congruency sequence effects to social-emotional stimuli in individuals with autism spectrum disorders.

Science.gov (United States)

Worsham, Whitney; Gray, Whitney E; Larson, Michael J; South, Mikle

2015-11-01

The modification of performance following conflict can be measured using conflict adaptation tasks thought to measure the change in the allocation of cognitive resources in order to reduce conflict interference and improve performance. While previous studies have suggested atypical processing during nonsocial cognitive control tasks, conflict adaptation (i.e. congruency sequence effects) for social-emotional stimuli have not been previously studied in autism spectrum disorder. A total of 32 participants diagnosed with autism spectrum disorder and 27 typically developing matched controls completed an emotional Stroop conflict task that required the classification of facial affect while simultaneously ignoring an overlaid affective word. Both groups showed behavioral evidence for emotional conflict adaptation based on response times and accuracy rates. However, the autism spectrum disorder group demonstrated a speed-accuracy trade-off manifested through significantly faster response times and decreased accuracy rates on trials containing conflict between the emotional face and the overlaid emotional word. Reduced selective attention toward socially relevant information may bias individuals with autism spectrum disorder toward more rapid processing and decision making even when conflict is present. Nonetheless, the loss of important information from the social stimuli reduces decision-making accuracy, negatively affecting the ability to adapt both cognitively and emotionally when conflict arises. © The Author(s) 2014.

Nitric oxide and TNFα are critical regulators of reversible lymph node vascular remodeling and adaptive immune response.

Directory of Open Access Journals (Sweden)

Stephanie L Sellers

Full Text Available Lymph node (LN vascular growth, at the level of the main arteriole, was recently characterized for the first time during infection. Arteriole diameter was shown to increase for at least seven days and to occur via a CD4(+ T cell dependent mechanism, with vascular expansion playing a critical role in regulating induction of adaptive immune response. Here, using intravital microscopy of the inguinal LN during herpes simplex type II (HSV-2 infection, the data provides the first studies that demonstrate arteriole expansion during infection is a reversible vascular event that occurs via eutrophic outward remodeling. Furthermore, using genetic ablation models, and pharmacological blockade, we reveal arteriole remodeling and LN hypertrophy to be dependent upon both endothelial nitric oxide synthase (eNOS and TNFα expression. Additionally, we reveal transient changes in nitric oxide (NO levels to be a notable feature of response to viral infection and LN vascular remodeling and provide evidence that mast cells are the critical source of TNFα required to drive arteriole remodeling. Overall, this study is the first to fully characterize LN arteriole vascular changes throughout the course of infection. It effectively reveals a novel role for NO and TNFα in LN cellularity and changes in LN vascularity, which represent key advances in understanding LN vascular physiology and adaptive immune response.

Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats

DEFF Research Database (Denmark)

Lai, Sarah W; de Heuvel, Elaine; Wallace, Laurie E

2017-01-01

mount immunohistochemistry for neurons (HuC/D, VIP, nNOS), plasma glucose, gut hormones, and body composition. RESULTS: Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2......-2 attenuated resection-induced increases in blood glucose and body fat loss. CONCLUSIONS: Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2......OBJECTIVE: To determine the effects of exogenous glucagon-like peptide-2 (GLP-2), with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats. BACKGROUND: GLP-2 is a gut hormone known to be trophic for small bowel mucosa...

Maternal programming of defensive responses through sustained effects on gene expression.

Science.gov (United States)

Zhang, Tie-Yuan; Bagot, Rose; Parent, Carine; Nesbitt, Cathy; Bredy, Timothy W; Caldji, Christian; Fish, Eric; Anisman, Hymie; Szyf, Moshe; Meaney, Michael J

2006-07-01

There are profound maternal effects on individual differences in defensive responses and reproductive strategies in species ranging literally from plants to insects to birds. Maternal effects commonly reflect the quality of the environment and are most likely mediated by the quality of the maternal provision (egg, propagule, etc.), which in turn determines growth rates and adult phenotype. In this paper we review data from the rat that suggest comparable forms of maternal effects on defensive responses stress, which are mediated by the effects of variations in maternal behavior on gene expression. Under conditions of environmental adversity maternal effects enhance the capacity for defensive responses in the offspring. In mammals, these effects appear to 'program' emotional, cognitive and endocrine systems towards increased sensitivity to adversity. In environments with an increased level of adversity, such effects can be considered adaptive, enhancing the probability of offspring survival to sexual maturity; the cost is that of an increased risk for multiple forms of pathology in later life.

Epigenetic Mechanisms Regulating Adaptive Responses to Targeted Kinase Inhibitors in Cancer.

Science.gov (United States)

Angus, Steven P; Zawistowski, Jon S; Johnson, Gary L

2018-01-06

Although targeted inhibition of oncogenic kinase drivers has achieved remarkable patient responses in many cancers, the development of resistance has remained a significant challenge. Numerous mechanisms have been identified, including the acquisition of gatekeeper mutations, activating pathway mutations, and copy number loss or gain of the driver or alternate nodes. These changes have prompted the development of kinase inhibitors with increased selectivity, use of second-line therapeutics to overcome primary resistance, and combination treatment to forestall resistance. In addition to genomic resistance mechanisms, adaptive transcriptional and signaling responses seen in tumors are gaining appreciation as alterations that lead to a phenotypic state change-often observed as an epithelial-to-mesenchymal shift or reversion to a cancer stem cell-like phenotype underpinned by remodeling of the epigenetic landscape. This epigenomic modulation driving cell state change is multifaceted and includes modulation of repressive and activating histone modifications, DNA methylation, enhancer remodeling, and noncoding RNA species. Consequently, the combination of kinase inhibitors with drugs targeting components of the transcriptional machinery and histone-modifying enzymes has shown promise in preclinical and clinical studies. Here, we review mechanisms of resistance to kinase inhibition in cancer, with special emphasis on the rewired kinome and transcriptional signaling networks and the potential vulnerabilities that may be exploited to overcome these adaptive signaling changes.

Smart plants, smart models? On adaptive responses in vegetation-soil systems

Science.gov (United States)

van der Ploeg, Martine; Teuling, Ryan; van Dam, Nicole; de Rooij, Gerrit

2015-04-01

Hydrological models that will be able to cope with future precipitation and evapotranspiration regimes need a solid base describing the essence of the processes involved [1]. The essence of emerging patterns at large scales often originates from micro-behaviour in the soil-vegetation-atmosphere system. A complicating factor in capturing this behaviour is the constant interaction between vegetation and geology in which water plays a key role. The resilience of the coupled vegetation-soil system critically depends on its sensitivity to environmental changes. To assess root water uptake by plants in a changing soil environment, a direct indication of the amount of energy required by plants to take up water can be obtained by measuring the soil water potential in the vicinity of roots with polymer tensiometers [2]. In a lysimeter experiment with various levels of imposed water stress the polymer tensiometer data suggest maize roots regulate their root water uptake on the derivative of the soil water retention curve, rather than the amount of moisture alone. As a result of environmental changes vegetation may wither and die, or these changes may instead trigger gene adaptation. Constant exposure to environmental stresses, biotic or abiotic, influences plant physiology, gene adaptations, and flexibility in gene adaptation [3-7]. To investigate a possible relation between plant genotype, the plant stress hormone abscisic acid (ABA) and the soil water potential, a proof of principle experiment was set up with Solanum Dulcamare plants. The results showed a significant difference in ABA response between genotypes from a dry and a wet environment, and this response was also reflected in the root water uptake. Adaptive responses may have consequences for the way species are currently being treated in models (single plant to global scale). In particular, model parameters that control root water uptake and plant transpiration are generally assumed to be a property of the plant

The wake-promoting drug modafinil stimulates specific hypothalamic circuits to promote adaptive stress responses in an animal model of PTSD.

Science.gov (United States)

Cohen, S; Ifergane, G; Vainer, E; Matar, M A; Kaplan, Z; Zohar, J; Mathé, A A; Cohen, H

2016-10-11

Pharmacotherapeutic intervention during traumatic memory consolidation has been suggested to alleviate or even prevent the development of posttraumatic stress disorder (PTSD). We recently reported that, in a controlled, prospective animal model, depriving rats of sleep following stress exposure prevents the development of a PTSD-like phenotype. Here, we report that administering the wake-promoting drug modafinil to rats in the aftermath of a stressogenic experience has a similar prophylactic effect, as it significantly reduces the prevalence of PTSD-like phenotype. Moreover, we show that the therapeutic value of modafinil appears to stem from its ability to stimulate a specific circuit within the hypothalamus, which ties together the neuropeptide Y, the orexin system and the HPA axis, to promote adaptive stress responses. The study not only confirms the value of sleep prevention and identifies the mechanism of action of a potential prophylactic treatment after traumatic exposure, but also contributes to understanding mechanisms underlying the shift towards adaptive behavioral response.

Space Mapping With Adaptive Response Correction for Microwave Design Optimization

DEFF Research Database (Denmark)

Koziel, S.; Bandler, J.W.; Madsen, Kaj

2009-01-01

at which the term was calculated, as in the surrogate model optimization process. In this paper, an adaptive response correction scheme is presented to work in conjunction with space-mapping optimization algorithms. This technique is designed to alleviate the difficulties of the standard output space......Output space mapping is a technique introduced to enhance the robustness of the space-mapping optimization process in case the space-mapped coarse model cannot provide sufficient matching with the fine model. The technique often works very well; however, in some cases it fails. Especially...

Spatial consequences of bleaching adaptation in cat retinal ganglion cells.

Science.gov (United States)

Bonds, A B; Enroth-Cugell, C

1981-01-01

1. Experiments were conducted to study the effects of localized bleaching on the centre responses of rod-driven cat retinal ganglion cells. 2. Stimulation as far as 2 degrees from the bleaching site yielded responses which were reduced nearly as much as those generated at the bleaching site. Bleaching in the receptive field middle reduced responsiveness at a site 1 degrees peripheral more than bleaching at that peripheral site itself. 3. The effectiveness of a bleach in reducing centre responsiveness is related to the sensitivity of the region in which the bleach is applied. 4. Response reduction after a 0.2 degree bleach followed the same temporal pattern for concentric test spots of from 0.2 to 1.8 degrees in diameter, implying a substantially uniform spread of adaptation within these bounds. 5. A linear trade-off between fraction of rhodopsin and area bleached over a range of 8:1 yields the same pattern of response reduction, implying that the non-linear nature of bleaching adaptation is a property of the adaptation pool rather than independent photoreceptors. PMID:7320894

Early and late rate of force development: differential adaptive responses to resistance training?

DEFF Research Database (Denmark)

Andersen, L L; Andersen, Jesper Løvind; Zebis, M K

2010-01-01

The objective of this study is to investigate the potentially opposing influence of qualitative and quantitative muscular adaptations in response to high-intensity resistance training on contractile rate of force development (RFD) in the early (200 ms) of rising muscle force. Fifteen healthy young......-intensity resistance training due to differential influences of qualitative and quantitative muscular adaptations on early and later phases of rising muscle force....... males participated in a 14-week resistance training intervention for the lower body and 10 matched subjects participated as controls. Maximal muscle strength (MVC) and RFD were measured during maximal voluntary isometric contraction of the quadriceps femoris muscle. Muscle biopsies were obtained from...

Plasticity in reproduction and growth among 52 range-wide populations of a Mediterranean conifer: adaptive responses to environmental stress.

Science.gov (United States)

Santos-Del-Blanco, L; Bonser, S P; Valladares, F; Chambel, M R; Climent, J

2013-09-01

A plastic response towards enhanced reproduction is expected in stressful environments, but it is assumed to trade off against vegetative growth and efficiency in the use of available resources deployed in reproduction [reproductive efficiency (RE)]. Evidence supporting this expectation is scarce for plants, particularly for long-lived species. Forest trees such as Mediterranean pines provide ideal models to study the adaptive value of allocation to reproduction vs. vegetative growth given their among-population differentiation for adaptive traits and their remarkable capacity to cope with dry and low-fertility environments. We studied 52 range-wide Pinus halepensis populations planted into two environmentally contrasting sites during their initial reproductive stage. We investigated the effect of site, population and their interaction on vegetative growth, threshold size for female reproduction, reproductive-vegetative size relationships and RE. We quantified correlations among traits and environmental variables to identify allocation trade-offs and ecotypic trends. Genetic variation for plasticity was high for vegetative growth, whereas it was nonsignificant for reproduction. Size-corrected reproduction was enhanced in the more stressful site supporting the expectation for adverse conditions to elicit plastic responses in reproductive allometry. However, RE was unrelated with early reproductive investment. Our results followed theoretical predictions and support that phenotypic plasticity for reproduction is adaptive under stressful environments. Considering expectations of increased drought in the Mediterranean, we hypothesize that phenotypic plasticity together with natural selection on reproductive traits will play a relevant role in the future adaptation of forest tree species. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

Proteomic analysis of the intestinal adaptation response reveals altered expression of fatty acid binding proteins following massive small bowel resection.

Science.gov (United States)

Stephens, Andrew N; Pereira-Fantini, Prue M; Wilson, Guineva; Taylor, Russell G; Rainczuk, Adam; Meehan, Katie L; Sourial, Magdy; Fuller, Peter J; Stanton, Peter G; Robertson, David M; Bines, Julie E

2010-03-05

Intestinal adaptation in response to the loss of the small intestine is essential to restore enteral autonomy in patients who have undergone massive small bowel resection (MSBR). In a proportion of patients, intestinal function is not restored, resulting in chronic intestinal failure (IF). Early referral of such patients for transplant provides the best prognosis; however, the molecular mechanisms underlying intestinal adaptation remain elusive and there is currently no convenient marker to predict whether patients will develop IF. We have investigated the adaptation response in a well-characterized porcine model of intestinal adaptation. 2D DIGE analysis of ileal epithelium from piglets recovering from massive small bowel resection (MSBR) identified over 60 proteins that changed specifically in MSBR animals relative to nonoperational or sham-operated controls. Three fatty acid binding proteins (L-FABP, FABP-6, and I-FABP) showed changes in MSBR animals. The expression changes and localization of each FABP were validated by immunoblotting and immunohistochemical analysis. FABP expression changes in MSBR animals occurred concurrently with altered triglyceride and bile acid metabolism as well as weight gain. The observed FABP expression changes in the ileal epithelium occur as part of the intestinal adaptation response and could provide a clinically useful marker to evaluate adaptation following MSBR.

Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations

Directory of Open Access Journals (Sweden)

Martino V. Franchi

2017-07-01

Full Text Available Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively; however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT is assumed to produce greater hypertrophy than concentric resistance training (CON RT. Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood.Thus, the present review aims to, (a critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b clarify the molecular mechanisms that may regulate such adaptations.We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions.

From nestling calls to fledgling silence: adaptive timing of change in response to aerial alarm calls.

Science.gov (United States)

Magrath, Robert D; Platzen, Dirk; Kondo, Junko

2006-09-22

Young birds and mammals are extremely vulnerable to predators and so should benefit from responding to parental alarm calls warning of danger. However, young often respond differently from adults. This difference may reflect: (i) an imperfect stage in the gradual development of adult behaviour or (ii) an adaptation to different vulnerability. Altricial birds provide an excellent model to test for adaptive changes with age in response to alarm calls, because fledglings are vulnerable to a different range of predators than nestlings. For example, a flying hawk is irrelevant to a nestling in a enclosed nest, but is dangerous to that individual once it has left the nest, so we predict that young develop a response to aerial alarm calls to coincide with fledging. Supporting our prediction, recently fledged white-browed scrubwrens, Sericornis frontalis, fell silent immediately after playback of their parents' aerial alarm call, whereas nestlings continued to calling despite hearing the playback. Young scrubwrens are therefore exquisitely adapted to the changing risks faced during development.

Probability differently modulating the effects of reward and punishment on visuomotor adaptation.

Science.gov (United States)

Song, Yanlong; Smiley-Oyen, Ann L

2017-12-01

Recent human motor learning studies revealed that punishment seemingly accelerated motor learning but reward enhanced consolidation of motor memory. It is not evident how intrinsic properties of reward and punishment modulate the potentially dissociable effects of reward and punishment on motor learning and motor memory. It is also not clear what causes the dissociation of the effects of reward and punishment. By manipulating probability of distribution, a critical property of reward and punishment, the present study demonstrated that probability had distinct modulation on the effects of reward and punishment in adapting to a sudden visual rotation and consolidation of the adaptation memory. Specifically, two probabilities of monetary reward and punishment distribution, 50 and 100%, were applied during young adult participants adapting to a sudden visual rotation. Punishment and reward showed distinct effects on motor adaptation and motor memory. The group that received punishments in 100% of the adaptation trials adapted significantly faster than the other three groups, but the group that received rewards in 100% of the adaptation trials showed marked savings in re-adapting to the same rotation. In addition, the group that received punishments in 50% of the adaptation trials that were randomly selected also had savings in re-adapting to the same rotation. Sensitivity to sensory prediction error or difference in explicit process induced by reward and punishment may likely contribute to the distinct effects of reward and punishment.

Adaptation of reach-to-grasp movement in response to force perturbations.

Science.gov (United States)

Rand, M K; Shimansky, Y; Stelmach, G E; Bloedel, J R

2004-01-01

This study examined how reach-to-grasp movements are modified during adaptation to external force perturbations applied on the arm during reach. Specifically, we examined whether the organization of these movements was dependent upon the condition under which the perturbation was applied. In response to an auditory signal, all subjects were asked to reach for a vertical dowel, grasp it between the index finger and thumb, and lift it a short distance off the table. The subjects were instructed to do the task as fast as possible. The perturbation was an elastic load acting on the wrist at an angle of 105 deg lateral to the reaching direction. The condition was modified by changing the predictability with which the perturbation was applied in a given trial. After recording unperturbed control trials, perturbations were applied first on successive trials (predictable perturbations) and then were applied randomly (unpredictable perturbations). In the early predictable perturbation trials, reach path length became longer and reaching duration increased. As more predictable perturbations were applied, the reach path length gradually decreased and became similar to that of control trials. Reaching duration also decreased gradually as the subjects adapted by exerting force against the perturbation. In addition, the amplitude of peak grip aperture during arm transport initially increased in response to repeated perturbations. During the course of learning, it reached its maximum and thereafter slightly decreased. However, it did not return to the normal level. The subjects also adapted to the unpredictable perturbations through changes in both arm transport and grasping components, indicating that they can compensate even when the occurrence of the perturbation cannot be predicted during the inter-trial interval. Throughout random perturbation trials, large grip aperture values were observed, suggesting that a conservative aperture level is set regardless of whether the

Adaptive response induced by low doses of ionizing radiation in human lymphocytes

International Nuclear Information System (INIS)

Frati, Diego Libkind; Bunge, Maria M.

2001-01-01

The term adaptive response (AR) applies to the phenomenon of protection or enhanced repair induced by a small dose of a mutagenic agent. In order to determine the existence of AR in human lymphocytes for two different irradiation schemes, microcultures of blood from 4 donors were irradiated. Samples were exposed 24 hours (hr) after phytohemagglutinin stimulation to an adapting dose of 0,01 Gy and to a challenging dose of 1,5 Gy either 6 or 24 hr later (irradiation scheme 24+30 or 24+48, respectively). Gamma radiation from a 2,5 MeV Linac was used in all experiments. A cytogenetic analysis of unstable chromosome aberrations was applied as the endpoint. High inter-individual variability was found for the first irradiation scheme: one expressed AR, two did not and the last showed an apparent synergistic response. For the second irradiation scheme, low mitotic indices (MI) were found, suggesting a G2 arrest. When a series of harvesting times were applied for the last donor, normal MI were obtained only harvesting after 58 hr. An AR was found when harvesting at 72 hr but not at 58 hr. (author)

Better predictions, better allocations: scientific advances and adaptation to climate change.

Science.gov (United States)

Freeman, Mark C; Groom, Ben; Zeckhauser, Richard J

2015-11-28

Climate science initially aspired to improve understanding of what the future would bring, and thereby produce appropriate public policies and effective international climate agreements. If that hope is dashed, as now seems probable, effective policies for adapting to climate change become critical. Climate science assumes new responsibilities by helping to foster more appropriate adaptation measures, which might include shifting modes or locales of production. This theoretical article focuses on two broader tools: consumption smoothing in response to the risk of future losses, and physical adaptation measures to reduce potential damages. It shows that informative signals on the effects of climate change facilitate better decisions on the use of each tool, thereby increasing social welfare. © 2015 The Author(s).

Effect of quality of family environment on the child's adaptation capabilities

Directory of Open Access Journals (Sweden)

Ivana Kreft

2008-08-01

Full Text Available The aim of the paper was to investigate how the quality of family environment is related to the child's adaptation capabilities. Child's adaptation was evaluated with a special assessment called SPP-3 (Systematic Psychological Assessment of a 3-year Old Child, that screens the population of 3-year olds to look for inadequate adaptation patterns. I assumed that in families where parents have higher education and where the environment is more stimulating children will show more effective and adaptive behaviour. Seventy-five children and parents who attended the psychological assessment in their regional hospitals first concluded the psychological examination (SPP-3 and then filled-in two questionnaires: The Family Environment Questionnaire (Zupančič, Podlesek, & Kavčič, 2004 and The Home Literacy Environment Questionnaire (Marjanovič Umek, Podlesek, & Fekonja, 2005. The results showed that quality of family environment does effect the child's adaptive capabilities and is associated with parental level of education. Of special importance for the child's socialization is the parents' ability to use effective control (to have consistent and clear demands. Hypothesis that the level of parental education affects the child's adaptation capabilities was not confirmed. Perhaps the parents' relations with the child are of greater importance, and these are probably not related to parents' education. The results show that child's adaptation capabilities are associated with parenting methods, so preventive psychological counselling may also be used to help parents choose more effective methods in order to allow the child to develop effective adaptive behaviour.

Arsenite Effects on Mitochondrial Bioenergetics in Human and Mouse Primary Hepatocytes Follow a Nonlinear Dose Response

Directory of Open Access Journals (Sweden)

Hemantkumar Chavan

2017-01-01

Full Text Available Arsenite is a known carcinogen and its exposure has been implicated in a variety of noncarcinogenic health concerns. Increased oxidative stress is thought to be the primary cause of arsenite toxicity and the toxic effect is thought to be linear with detrimental effects reported at all concentrations of arsenite. But the paradigm of linear dose response in arsenite toxicity is shifting. In the present study we demonstrate that arsenite effects on mitochondrial respiration in primary hepatocytes follow a nonlinear dose response. In vitro exposure of primary hepatocytes to an environmentally relevant, moderate level of arsenite results in increased oxidant production that appears to arise from changes in the expression and activity of respiratory Complex I of the mitochondrial proton circuit. In primary hepatocytes the excess oxidant production appears to elicit adaptive responses that promote resistance to oxidative stress and a propensity to increased proliferation. Taken together, these results suggest a nonlinear dose-response characteristic of arsenite with low-dose arsenite promoting adaptive responses in a process known as mitohormesis, with transient increase in ROS levels acting as transducers of arsenite-induced mitohormesis.

Adaptation of perceptual responses to low-load blood flow restriction training

DEFF Research Database (Denmark)

Martín-Hernández, Juan; Ruiz-Aguado, Jorge; Herrero, Azael Juan

2017-01-01

The purpose of this study was to determine the adaptive response of ratings of perceived exertion (RPE) and pain over six consecutive training sessions. Thirty subjects were assigned to either a blood flow restricted training group (BFRT) or a high intensity group (HIT). BFRT group performed four...... sets (30+15+15+15, respectively) of unilateral leg extension at an intensity of 20% one repetition maximum (1RM) while a restrictive cuff was applied to the most proximal part of the leg. HIT group performed 3 sets of eight repetitions with 85%1RM. RPE and pain were assessed following every exercise.......01). No between-group differences were found at any time point. In summary, BFRT induces a high perceptual response to training. However, this perceptual response is rapidly attenuated, leading to values similar to those experienced during HIT. Low load BFRT should not be limited to highly motivated individuals...

Rapid adaptation of the stimulatory effect of CO2 on brain norepinephrine metabolism.

Science.gov (United States)

Stone, E A

1983-12-01

The present study examined the effects of exposure of rats to elevated environmental levels of CO2 on norepinephrine metabolism in the hypothalamus and other regions of the brain. In confirmation of previous findings by others CO2 at 10 or 15% was found to elevate both dopa accumulation after dopa decarboxylase inhibition and norepinephrine utilization after tyrosine hydroxylase inhibition. These effects however were found to be transient occurring only during the first 30 min of 2.5 h exposure. In this regard CO2 differs from another form of stress, restraint which produces a sustained 2.5 h increase of dopa accumulation and NE accumulation. Restraint was also more effective than CO2 in depleting endogenous stores of hypothalamic NE. The factor responsible for the adaptation of the catecholamine response to CO2 was not identified although it was shown not to be hypothermia and it was reversed by a 2 h CO2-free recovery period.

Lithocholic acid controls adaptive immune responses by inhibition of Th1 activation through the Vitamin D receptor.

Science.gov (United States)

Pols, Thijs W H; Puchner, Teresa; Korkmaz, H Inci; Vos, Mariska; Soeters, Maarten R; de Vries, Carlie J M

2017-01-01

Bile acids are established signaling molecules next to their role in the intestinal emulsification and uptake of lipids. We here aimed to identify a potential interaction between bile acids and CD4+ Th cells, which are central in adaptive immune responses. We screened distinct bile acid species for their potency to affect T cell function. Primary human and mouse CD4+ Th cells as well as Jurkat T cells were used to gain insight into the mechanism underlying these effects. We found that unconjugated lithocholic acid (LCA) impedes Th1 activation as measured by i) decreased production of the Th1 cytokines IFNγ and TNFαα, ii) decreased expression of the Th1 genes T-box protein expressed in T cells (T-bet), Stat-1 and Stat4, and iii) decreased STAT1α/β phosphorylation. Importantly, we observed that LCA impairs Th1 activation at physiological relevant concentrations. Profiling of MAPK signaling pathways in Jurkat T cells uncovered an inhibition of ERK-1/2 phosphorylation upon LCA exposure, which could provide an explanation for the impaired Th1 activation. LCA induces these effects via Vitamin D receptor (VDR) signaling since VDR RNA silencing abrogated these effects. These data reveal for the first time that LCA controls adaptive immunity via inhibition of Th1 activation. Many factors influence LCA levels, including bile acid-based drugs and gut microbiota. Our data may suggest that these factors also impact on adaptive immunity via a yet unrecognized LCA-Th cell axis.

What works for you? Using teacher feedback to inform adaptations of pivotal response training for classroom use.

Science.gov (United States)

Stahmer, Aubyn C; Suhrheinrich, Jessica; Reed, Sarah; Schreibman, Laura

2012-01-01

Several evidence-based practices (EBPs) have been identified as efficacious for the education of students with autism spectrum disorders (ASD). However, effectiveness research has rarely been conducted in schools and teachers express skepticism about the clinical utility of EBPs for the classroom. Innovative methods are needed to optimally adapt EBPs for community use. This study utilizes qualitative methods to identify perceived benefits and barriers of classroom implementation of a specific EBP for ASD, Pivotal Response Training (PRT). Teachers' perspectives on the components of PRT, use of PRT as a classroom intervention strategy, and barriers to the use of PRT were identified through guided discussion. Teachers found PRT valuable; however, they also found some components challenging. Specific teacher recommendations for adaptation and resource development are discussed. This process of obtaining qualitative feedback from frontline practitioners provides a generalizable model for researchers to collaborate with teachers to optimally promote EBPs for classroom use.

Countermeasures to Enhance Sensorimotor Adaptability

Science.gov (United States)

Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. C.; Miller, C. A.; Cohen, H. S.

2011-01-01

During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The goal of our current project is to develop a sensorimotor adaptability (SA) training program to facilitate rapid adaptation to novel gravitational environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene that provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. We have conducted a series of studies that have shown: Training using a combination of modified visual flow and support surface motion during treadmill walking enhances locomotor adaptability to a novel sensorimotor environment. Trained individuals become more proficient at performing multiple competing tasks while walking during adaptation to novel discordant sensorimotor conditions. Trained subjects can retain their increased level of adaptability over a six months period. SA training is effective in producing increased adaptability in a more complex over-ground ambulatory task on an obstacle course. This confirms that for a complex task like walking, treadmill training contains enough of the critical features of overground walking to be an effective training modality. The structure of individual training sessions can be optimized to promote fast/strategic motor learning. Training sessions that each contain short-duration exposures to multiple perturbation stimuli allows subjects to acquire a greater ability to rapidly reorganize appropriate response strategies when encountering a novel sensory environment. Individual sensory biases (i.e. increased visual dependency) can predict adaptive responses to novel sensory environments suggesting that customized training prescriptions can be developed to enhance

Context-dependent planktivory: interacting effects of turbidity and predation risk on adaptive foraging

Science.gov (United States)

Pangle, Kevin L.; Malinich, Timothy D.; Bunnell, David B.; DeVries, Dennis R.; Ludsin, Stuart A.

2012-01-01

By shaping species interactions, adaptive phenotypic plasticity can profoundly influence ecosystems. Predicting such outcomes has proven difficult, however, owing in part to the dependence of plasticity on the environmental context. Of particular relevance are environmental factors that affect sensory performance in organisms in ways that alter the tradeoffs associated with adaptive phenotypic responses. We explored the influence of turbidity, which simultaneously and differentially affects the sensory performance of consumers at multiple trophic levels, on the indirect effect of a top predator (piscivorous fish) on a basal prey resource (zooplankton) that is mediated through changes in the plastic foraging behavior of an intermediate consumer (zooplanktivorous fish). We first generated theoretical predictions of the adaptive foraging response of a zooplanktivore across wide gradients of turbidity and predation risk by a piscivore. Our model predicted that predation risk can change the negative relationship between intermediate consumer foraging and turbidity into a humped-shaped (unimodal) one in which foraging is low in both clear and highly turbid conditions due to foraging-related risk and visual constraints, respectively. Consequently, the positive trait-mediated indirect effect (TMIE) of the top predator on the basal resource is predicted to peak at low turbidity and decline thereafter until it reaches an asymptote of zero at intermediate turbidity levels (when foraging equals that which is predicted when the top predator is absent). We used field observations and a laboratory experiment to test our model predictions. In support, we found humped-shaped relationships between planktivory and turbidity for several zooplanktivorous fishes from diverse freshwater ecosystems with predation risk. Further, our experiment demonstrated that predation risk reduced zooplanktivory by yellow perch (Perca flavescens) at a low turbidity, but had no effect on consumption at

Rethinking Social Barriers to Effective Adaptive Management

Science.gov (United States)

West, Simon; Schultz, Lisen; Bekessy, Sarah

2016-09-01

Adaptive management is an approach to environmental management based on learning-by-doing, where complexity, uncertainty, and incomplete knowledge are acknowledged and management actions are treated as experiments. However, while adaptive management has received significant uptake in theory, it remains elusively difficult to enact in practice. Proponents have blamed social barriers and have called for social science contributions. We address this gap by adopting a qualitative approach to explore the development of an ecological monitoring program within an adaptive management framework in a public land management organization in Australia. We ask what practices are used to enact the monitoring program and how do they shape learning? We elicit a rich narrative through extensive interviews with a key individual, and analyze the narrative using thematic analysis. We discuss our results in relation to the concept of `knowledge work' and Westley's 2002) framework for interpreting the strategies of adaptive managers—`managing through, in, out and up.' We find that enacting the program is conditioned by distinct and sometimes competing logics—scientific logics prioritizing experimentation and learning, public logics emphasizing accountability and legitimacy, and corporate logics demanding efficiency and effectiveness. In this context, implementing adaptive management entails practices of translation to negotiate tensions between objective and situated knowledge, external experts and organizational staff, and collegiate and hierarchical norms. Our contribution embraces the `doing' of learning-by-doing and marks a shift from conceptualizing the social as an external barrier to adaptive management to be removed to an approach that situates adaptive management as social knowledge practice.

The Effect of Aging on the Dynamics of Reactive and Proactive Cognitive Control of Response Interference.

Science.gov (United States)

Xiang, Ling; Zhang, Baoqiang; Wang, Baoxi; Jiang, Jun; Zhang, Fenghua; Hu, Zhujing

2016-01-01

A prime-target interference task was used to investigate the effects of cognitive aging on reactive and proactive control after eliminating frequency confounds and feature repetitions from the cognitive control measures. We used distributional analyses to explore the dynamics of the two control functions by distinguishing the strength of incorrect response capture and the efficiency of suppression control. For reactive control, within-trial conflict control and between-trial conflict adaption were analyzed. The statistical analysis showed that there were no reliable between-trial conflict adaption effects for either young or older adults. For within-trial conflict control, the results revealed that older adults showed larger interference effects on mean RT and mean accuracy. Distributional analyses showed that the decline mainly stemmed from inefficient suppression rather than from stronger incorrect responses. For proactive control, older adults showed comparable proactive conflict resolution to young adults on mean RT and mean accuracy. Distributional analyses showed that older adults were as effective as younger adults in adjusting their responses based on congruency proportion information to minimize automatic response capture and actively suppress the direct response activation. The results suggest that older adults were less proficient at suppressing interference after conflict was detected but can anticipate and prevent inference in response to congruency proportion manipulation. These results challenge earlier views that older adults have selective deficits in proactive control but intact reactive control.

The neural response properties and cortical organization of a rapidly adapting muscle sensory group response that overlaps with the frequencies that elicit the kinesthetic illusion.

Science.gov (United States)

Marasco, Paul D; Bourbeau, Dennis J; Shell, Courtney E; Granja-Vazquez, Rafael; Ina, Jason G

2017-01-01

Kinesthesia is the sense of limb movement. It is fundamental to efficient motor control, yet its neurophysiological components remain poorly understood. The contributions of primary muscle spindles and cutaneous afferents to the kinesthetic sense have been well studied; however, potential contributions from muscle sensory group responses that are different than the muscle spindles have not been ruled out. Electrophysiological recordings in peripheral nerves and brains of male Sprague Dawley rats with a degloved forelimb preparation provide evidence of a rapidly adapting muscle sensory group response that overlaps with vibratory inputs known to generate illusionary perceptions of limb movement in humans (kinesthetic illusion). This group was characteristically distinct from type Ia muscle spindle fibers, the receptor historically attributed to limb movement sensation, suggesting that type Ia muscle spindle fibers may not be the sole carrier of kinesthetic information. The sensory-neural structure of muscles is complex and there are a number of possible sources for this response group; with Golgi tendon organs being the most likely candidate. The rapidly adapting muscle sensory group response projected to proprioceptive brain regions, the rodent homolog of cortical area 3a and the second somatosensory area (S2), with similar adaption and frequency response profiles between the brain and peripheral nerves. Their representational organization was muscle-specific (myocentric) and magnified for proximal and multi-articulate limb joints. Projection to proprioceptive brain areas, myocentric representational magnification of muscles prone to movement error, overlap with illusionary vibrational input, and resonant frequencies of volitional motor unit contraction suggest that this group response may be involved with limb movement processing.

Adaptation of postural recovery responses to a vestibular sensory illusion in individuals with Parkinson disease and healthy controls.

Science.gov (United States)

Lester, Mark E; Cavanaugh, James T; Foreman, K Bo; Shaffer, Scott W; Marcus, Robin; Dibble, Leland E

2017-10-01

The ability to adapt postural responses to sensory illusions diminishes with age and is further impaired by Parkinson disease. However, limited information exists regarding training-related adaptions of sensory reweighting in these populations. This study sought to determine whether Parkinson disease or age would differentially affect acute postural recovery or adaptive postural responses to novel or repeated exposure to sensory illusions using galvanic vestibular stimulation during quiet stance. Acutely, individuals with Parkinson disease demonstrated larger center of pressure coefficient of variation compared to controls. Unlike individuals with Parkinson disease and asymptomatic older adults, healthy young adults acutely demonstrated a reduction in Sample Entropy to the sensory illusion. Following a period of consolidation Sample Entropy increased in the healthy young group, which coincided with a decreased center of pressure coefficient of variation. Similar changes were not observed in the Parkinson disease or older adult groups. Taken together, these results suggest that young adults learn to adapt to vestibular illusion in a more robust manner than older adults or those with Parkinson disease. Further investigation into the nature of this adaptive difference is warranted. Published by Elsevier Ltd.

Oxidative stress as a significant factor for development of an adaptive response in irradiated and nonirradiated human lymphocytes after inducing the bystander effect by low-dose X-radiation

Energy Technology Data Exchange (ETDEWEB)

Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Science, ul. Moskvorechye, 1, Moscow 115478 (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Egolina, Natalya A.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Science, ul. Moskvorechye, 1, Moscow 115478 (Russian Federation)

2009-10-02

X-radiation (10 cGy) was shown to induce in human lymphocytes transposition of homologous chromosomes loci from the membrane towards the centre of the nucleus and activation of the chromosomal nucleolus-forming regions (NFRs). These effects are transmitted by means of extracellular DNA (ecDNA) fragments to nonirradiated cells (the so-called bystander effect, BE). We demonstrated that in the development of the BE an important role is played by oxidative stress (which is brought about by low radiation doses and ecDNA fragments of the culture medium of the irradiated cells), by an enzyme of apoptosis called caspase-3, and by DNA-binding receptors of the bystander cells, presumably TLR9. Proposed herein is a scheme of the development of an adaptive response and the BE on exposure to radiation. Ionizing radiation induces apoptosis of the radiosensitive fraction of cells due to the development of the 'primary' oxidative stress (OS). DNA fragments of apoptotic cells are released into the intercellular space and interact with the DNA-binding receptors of the bystander cells. This interaction activates in lymphocytes signalling pathways associated with synthesis of the reactive oxygen species and nitrogen species, i.e., induces secondary oxidative stress accompanied by apoptosis of part of the cells, etc. Hence, single exposure to radiation may be followed by relatively long-lasting in the cellular population oxidative stress contributing to the development of an adaptive response. We thus believe that ecDNA of irradiated apoptotic lymphocytes is a significant factor of stress-signalling.

Climate adaptation in NVE's areas of responsibility - Strategy 2010 - 2014; Klimatilpasning innen NVEs ansvarsomraader - Strategi 2010 - 2014

Energy Technology Data Exchange (ETDEWEB)

Hamarsland, Arne T. (ed.)

2010-09-15

NVE has developed a comprehensive climate change strategies within their areas of responsibility. There is a systematic review of how a future climate change will affect NVE management areas; how to meet challenges, vulnerabilities, opportunities and proposals for adaptation measures. Climate adaptation is a dynamic process. It is therefore necessary to follow up the work continuously and correct direction at regular intervals. Climate change adaptation strategy of adaptation measures is a foundation and a direction sensor in NVE's business planning. (AG)

Adaptive responses of mouse skeletal muscle to contractile activity: The effect of age.

Science.gov (United States)

Vasilaki, A; McArdle, F; Iwanejko, L M; McArdle, A

2006-11-01

This study has characterised the time course of two major transcriptional adaptive responses to exercise (changes in antioxidant defence enzyme activity and heat shock protein (HSP) content) in muscles of adult and old male mice following isometric contractions and has examined the mechanisms involved in the age-related reduction in transcription factor activation. Muscles of B6XSJL mice were subjected to isometric contractions and analysed for antioxidant defence enzyme activities, heat shock protein content and transcription factor DNA binding activity. Data demonstrated a significant increase in superoxide dismutase (SOD) and catalase activity and HSP content of muscles of adult mice following contractile activity which was associated with increased activation of the transcription factors, nuclear factor-kappaB (NF-kappaB), activator protein-1 (AP-1) and heat shock factor (HSF) following contractions. Significant increases in SOD and catalase activity and heat shock cognate (HSC70) content were seen in quiescent muscles of old mice. The increase in antioxidant defence enzyme activity following contractile activity seen in muscles of adult mice was not seen in muscles of old mice and this was associated with a failure to fully activate NF-kappaB and AP-1 following contractions. In contrast, although the production of HSPs was also reduced in muscles of old mice following contractile activity compared with muscles of adult mice following contractions, this was not due to a gross reduction in the DNA binding activity of HSF.

Feedback effect of human physical and psychological adaption on time period of thermal adaption in naturally ventilated building

DEFF Research Database (Denmark)

liu, weiwei; Huangfu, Hao; Xiong, Jing

2014-01-01

This study proposed a method to determine time period of thermal adaption for occupants in naturally ventilated building, and analyzed the synergistic and separate feedback effect of the physical and psychological adaption modes on the time period of thermal adaption. Using the method, the values...... of the time period of thermal adaption were obtained on the basis of the data from a long-term field survey conducted in two typical naturally ventilated offices located in Changsha, China. The results showed that the occupants need to take 4.25 days to fully adapt to a step-change in outdoor air temperature...

ADAPTIVE CAPACITIES OF FARMERS TO CLIMATE CHANGE ADAPTATION STRATEGIES AND THEIR EFFECTS ON RICE PRODUCTION IN THE NORTHERN REGION OF GHANA

Directory of Open Access Journals (Sweden)

Franklin Nantui Mabe

2012-11-01

Full Text Available This study estimated the adaptive capacities of farmers to climate change adaptation strategies and their effects on rice production in the Northern Region of Ghana. The adaptive capacities of rice farmers were estimated quantitatively and categorized into high, moderate and low adaptive capacities. Double logarithmic regression model of Cobb-Douglas production function was used to quantity the effects of adaptive capacities of farmers on rice production. On the average, the farmers interviewed are moderately adaptive to climate change. Also, high adaptive farmers obtain nine more bags of 50 kg bag of paddy rice than farmers with low adaptive capacities. Therefore, the more a farmer has the ability to adjust to climate change, the more the number of bags of rice he or she obtains. Rice farmers should be empowered through better extension services in order to attain high adaptive capacity status so as to help them obtain more rice output.

Using Ontology to Drive an Adaptive Learning Interface

Directory of Open Access Journals (Sweden)

Andrew Crapo

2004-10-01

Full Text Available Intelligent, adaptive interfaces are a pre-requisite to elevating computer-based applications to the realm of collaborative decision support in complex, relatively open-ended domains such as logistics and planning. This is because the composition and effective presentation of even the most useful information must be tailored to constantly changing circumstances. Our objective is to not only achieve an adaptive human-machine interface, but to imbue the software with a significant portion of the responsibility for effectively controlling the adaptation, freeing the user from unnecessary distraction and making the human-machine relationship more collaborative in nature. The foundational concepts of interface adaptation are discussed and a specific logistics application is described as an example.

No adaptive response is induced by chronic low-dose radiation from Ra-226 in the CHSE/F fish embryonic cell line and the HaCaT human epithelial cell line

Energy Technology Data Exchange (ETDEWEB)

Shi, Xiaopei, E-mail: shix22@mcmaster.ca; Mothersill, Carmel; Seymour, Colin

2016-11-15

Purpose: To determine whether chronic low-dose α-particle radiation from Ra-226 over multiple cell generations can lead to an adaptive response in CHSE/F fish embryonic cells or HaCaT human epithelial cells receiving subsequent acute high-dose γ-ray radiation. Methods: CHSE/F and HaCaT cells were exposed to very low doses of Ra-226 in medium for multiple generations prior to being challenged by a higher dose γ-ray radiation. The clonogenic assay was used to test the clonogenic survival of cells with or without being pretreated by radiation from Ra-226. Results: In general, pretreatment with chronic radiation has no significant influence on the reaction of cells to the subsequent challenge radiation. Compared to unprimed cells, the change in clonogenic survival of primed cells after receiving challenge radiation is mainly due to the influence of the chronic exposure, and there's little adaptive response induced. However at several dose points, pretreatment of CHSE/F fish cells with chronic radiation resulted in a radiosensitive response to a challenge dose of γ-ray radiation, and pretreatment of HaCaT cells resulted in no effect except for a slightly radioresistant response to the challenge radiation which was not significant. Conclusion: The results suggest that chronic low-dose radiation is not effective enough to induce adaptive response. There was a difference between human and fish cells and it may be important to consider results from multiple species before making conclusions about effects of chronic or low doses of radiation in the environment. The term “radiosensitive” or “adaptive” make no judgment about whether such responses are ultimately beneficial or harmful. - Highlights: • No obvious adaptive response is induced by chronic low-dose radiation from Ra-226. • Priming radiation from Ra-226 sensitized CHSE/F cells to the challenge radiation. • Linear model is inconsistent with current work using chronic low-dose radiation.

TNF-driven adaptive response mediates resistance to EGFR inhibition in lung cancer.

Science.gov (United States)

Gong, Ke; Guo, Gao; Gerber, David E; Gao, Boning; Peyton, Michael; Huang, Chun; Minna, John D; Hatanpaa, Kimmo J; Kernstine, Kemp; Cai, Ling; Xie, Yang; Zhu, Hong; Fattah, Farjana J; Zhang, Shanrong; Takahashi, Masaya; Mukherjee, Bipasha; Burma, Sandeep; Dowell, Jonathan; Dao, Kathryn; Papadimitrakopoulou, Vassiliki A; Olivas, Victor; Bivona, Trever G; Zhao, Dawen; Habib, Amyn A

2018-06-01

Although aberrant EGFR signaling is widespread in cancer, EGFR inhibition is effective only in a subset of non-small cell lung cancer (NSCLC) with EGFR activating mutations. A majority of NSCLCs express EGFR wild type (EGFRwt) and do not respond to EGFR inhibition. TNF is a major mediator of inflammation-induced cancer. We find that a rapid increase in TNF level is a universal adaptive response to EGFR inhibition in NSCLC, regardless of EGFR status. EGFR signaling actively suppresses TNF mRNA levels by inducing expression of miR-21, resulting in decreased TNF mRNA stability. Conversely, EGFR inhibition results in loss of miR-21 and increased TNF mRNA stability. In addition, TNF-induced NF-κB activation leads to increased TNF transcription in a feed-forward loop. Inhibition of TNF signaling renders EGFRwt-expressing NSCLC cell lines and an EGFRwt patient-derived xenograft (PDX) model highly sensitive to EGFR inhibition. In EGFR-mutant oncogene-addicted cells, blocking TNF enhances the effectiveness of EGFR inhibition. EGFR plus TNF inhibition is also effective in NSCLC with acquired resistance to EGFR inhibition. We suggest concomitant EGFR and TNF inhibition as a potentially new treatment approach that could be beneficial for a majority of lung cancer patients.

Deep-sea pennatulaceans (sea pens) - recent discoveries, morphological adaptations, and responses to benthic oceanographic parameters

Science.gov (United States)

Williams, G. C.

2015-12-01

Pennatulaceans are sessile, benthic marine organisms that are bathymetrically wide-ranging, from the intertidal to approximately 6300 m in depth, and are conspicuous constituents of deep-sea environments. The vast majority of species are adapted for anchoring in soft sediments by the cylindrical peduncle - a muscular hydrostatic skeleton. However, in the past decade a few species ("Rockpens") have been discovered and described that can attach to hard substratum such as exposed rocky outcrops at depths between 669 and 1969 m, by a plunger-like adaptation of the base of the peduncle. Of the thirty-six known genera, eleven (or 30%) have been recorded from depths greater than 1000 m. The pennatulacean depth record holders are an unidentified species of Umbellula from 6260 m in the Peru-Chile Trench and a recently-discovered and described genus and species, Porcupinella profunda, from 5300 m the Porcupine Abyssal Plain of the northeastern Atlantic. A morphologically-differentiated type of polyp (acrozooid) have recently been discovered and described in two genera of shallow-water coral reef sea pens. Acrozooids apparently represent asexual buds and presumably can detach from the adult to start clonal colonies through asexual budding. Acrozooids are to be expected in deep-sea pennatulaceans, but so far have not been observed below 24 m in depth. Morphological responses at depths greater than 1000 m in deep-sea pennatulaceas include: fewer polyps, larger polyps, elongated stalks, and clustering of polyps along the rachis. Responses to deep-ocean physical parameters and anthropogenic changes that could affect the abundance and distribution of deep-sea pennatulaceans include changes in bottom current flow and food availability, changes in seawater temperature and pH, habitat destruction by fish trawling, and sunken refuse pollution. No evidence of the effects of ocean acidification or other effects of anthropogenic climate change in sea pens of the deep-sea has been

Farmers’ Perceptions about Adaptation Practices to Climate Change and Barriers to Adaptation: A Micro-Level Study in Ghana

Directory of Open Access Journals (Sweden)

Francis Ndamani

2015-08-01

Full Text Available This study analyzed the farmer-perceived importance of adaptation practices to climate change and examined the barriers that impede adaptation. Perceptions about causes and effects of long-term changes in climatic variables were also investigated. A total of 100 farmer-households were randomly selected from four communities in the Lawra district of Ghana. Data was collected using semi-structured questionnaires and focus group discussions (FGDs. The results showed that 87% of respondents perceived a decrease in rainfall amount, while 82% perceived an increase in temperature over the past 10 years. The study revealed that adaptation was largely in response to dry spells and droughts (93.2% rather than floods. About 67% of respondents have adjusted their farming activities in response to climate change. Empirical results of the weighted average index analysis showed that farmers ranked improved crop varieties and irrigation as the most important adaptation measures. It also revealed that farmers lacked the capacity to implement the highly ranked adaptation practices. The problem confrontation index analysis showed that unpredictable weather, high cost of farm inputs, limited access to weather information, and lack of water resources were the most critical barriers to adaptation. This analysis of adaptation practices and constraints at farmer level will help facilitate government policy formulation and implementation.

Interval for the expression of the adaptive response induced by gamma radiation in leucocytes of mouse In vivo; Intervalo para la expresion de la respuesta adaptativa inducida por radiacion gamma en leucocitos de raton In vivo

Energy Technology Data Exchange (ETDEWEB)

Mendiola C, M T; Morales R, P [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2002-07-01

The interval between the adaptive gamma radiation dose (0.01 Gy) and challenge (1.0 Gy) capable to induce the maximum expression of the adaptive response in lymphocytes of mouse In vivo. The animals were exposed to the mentioned doses with different intervals among both (1, 1.5, 5 or 18 hr). By means of the unicellular electrophoresis in gel technique, four damage parameters were analysed. The results showed that from the 1 hr interval an adaptive response was produced since in the pretreated organisms with 0.01 Gy the cells present lesser damage than in those not adapted. The maximum response was induced with the intervals between 2.5 and 5 hr and even though it persisted until 18 hr, the effect was reducing. (Author)

Beyond exposure, sensitivity and adaptive capacity: A response based ecological framework to assess species climate change vulnerability

Science.gov (United States)

Fortini, Lucas B.; Schubert, Olivia

2017-01-01

As the impacts of global climate change on species are increasingly evident, there is a clear need to adapt conservation efforts worldwide. Species vulnerability assessments (VAs) are increasingly used to summarize all relevant information to determine a species’ potential vulnerability to climate change and are frequently the first step in informing climate adaptation efforts. VAs commonly integrate multiple sources of information by utilizing a framework that distinguishes factors relevant to species exposure, sensitivity, and adaptive capacity. However, this framework was originally developed for human systems, and its use to evaluate species vulnerability has serious practical and theoretical limitations. By instead defining vulnerability as the degree to which a species is unable to exhibit any of the responses necessary for persistence under climate change (i.e., toleration of projected changes, migration to new climate-compatible areas, enduring in microrefugia, and evolutionary adaptation), we can bring VAs into the realm of ecological science without applying borrowed abstract concepts that have consistently challenged species-centric research and management. This response-based framework to assess species vulnerability to climate change allows better integration of relevant ecological data and past research, yielding results with much clearer implications for conservation and research prioritization.

Characterization of an adaptive immune response in microsatellite-instable colorectal cancer

Science.gov (United States)

Boissière-Michot, Florence; Lazennec, Gwendal; Frugier, Hélène; Jarlier, Marta; Roca, Lise; Duffour, Jacqueline; Du Paty, Emilie; Laune, Daniel; Blanchard, France; Le Pessot, Florence; Sabourin, Jean-Christophe; Bibeau, Frédéric

2014-01-01

Sporadic or hereditary colorectal cancer (CRC) with microsatellite instability (MSI) is frequently characterized by inflammatory lymphocytic infiltration and tends to be associated with a better outcome than microsatellite stable (MSS) CRC, probably reflecting a more effective immune response. We investigated inflammatory mechanisms in 48 MSI CRCs and 62 MSS CRCs by analyzing: (1) the expression of 48 cytokines using Bio-Plex multiplex cytokine assays, and (2) the in situ immune response by immunohistochemical analysis with antibodies against CD3 (T lymphocytes), CD8 (cytotoxic T lymphocytes), CD45RO (memory T lymphocytes), T-bet (Th1 CD4 cells), and FoxP3 (regulatory T cells). MSI CRC exhibited significantly higher expression of CCL5 (RANTES), CXCL8 (IL-8), CXCL9 (MIG), IL-1β, CXCL10 (IP-10), IL-16, CXCL1 (GROα), and IL-1ra, and lower expression of MIF, compared with MSS CRC. Immunohistochemistry combined with image analysis indicated that the density of CD3+, CD8+, CD45RO+, and T-bet+ T lymphocytes was higher in MSI CRC than in MSS CRC, whereas the number of regulatory T cells (FoxP3+) was not statistically different between the groups. These results indicate that MSI CRC is associated with a specific cytokine expression profile that includes CCL5, CXCL10, and CXCL9, which are involved in the T helper type 1 (Th1) response and in the recruitment of memory CD45RO+ T cells. Our findings highlight the major role of adaptive immunity in MSI CRC and provide a possible explanation for the more favorable prognosis of this CRC subtype. PMID:25101223

Adaptation and inhibition underlie responses to time-varying interaural phase cues in a model of inferior colliculus neurons.

Science.gov (United States)

Borisyuk, Alla; Semple, Malcolm N; Rinzel, John

2002-10-01

A mathematical model was developed for exploring the sensitivity of low-frequency inferior colliculus (IC) neurons to interaural phase disparity (IPD). The formulation involves a firing-rate-type model that does not include spikes per se. The model IC neuron receives IPD-tuned excitatory and inhibitory inputs (viewed as the output of a collection of cells in the medial superior olive). The model cell possesses cellular properties of firing rate adaptation and postinhibitory rebound (PIR). The descriptions of these mechanisms are biophysically reasonable, but only semi-quantitative. We seek to explain within a minimal model the experimentally observed mismatch between responses to IPD stimuli delivered dynamically and those delivered statically (McAlpine et al. 2000; Spitzer and Semple 1993). The model reproduces many features of the responses to static IPD presentations, binaural beat, and partial range sweep stimuli. These features include differences in responses to a stimulus presented in static or dynamic context: sharper tuning and phase shifts in response to binaural beats, and hysteresis and "rise-from-nowhere" in response to partial range sweeps. Our results suggest that dynamic response features are due to the structure of inputs and the presence of firing rate adaptation and PIR mechanism in IC cells, but do not depend on a specific biophysical mechanism. We demonstrate how the model's various components contribute to shaping the observed phenomena. For example, adaptation, PIR, and transmission delay shape phase advances and delays in responses to binaural beats, adaptation and PIR shape hysteresis in different ranges of IPD, and tuned inhibition underlies asymmetry in dynamic tuning properties. We also suggest experiments to test our modeling predictions: in vitro simulation of the binaural beat (phase advance at low beat frequencies, its dependence on firing rate), in vivo partial range sweep experiments (dependence of the hysteresis curve on

Lipidomic Adaptations in White and Brown Adipose Tissue in Response to Exercise Demonstrate Molecular Species-Specific Remodeling

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Francis J. May

2017-02-01

Full Text Available Exercise improves whole-body metabolic health through adaptations to various tissues, including adipose tissue, but the effects of exercise training on the lipidome of white adipose tissue (WAT and brown adipose tissue (BAT are unknown. Here, we utilize MS/MSALL shotgun lipidomics to determine the molecular signatures of exercise-induced adaptations to subcutaneous WAT (scWAT and BAT. Three weeks of exercise training decrease specific molecular species of phosphatidic acid (PA, phosphatidylcholines (PC, phosphatidylethanolamines (PE, and phosphatidylserines (PS in scWAT and increase specific molecular species of PC and PE in BAT. Exercise also decreases most triacylglycerols (TAGs in scWAT and BAT. In summary, exercise-induced changes to the scWAT and BAT lipidome are highly specific to certain molecular lipid species, indicating that changes in tissue lipid content reflect selective remodeling in scWAT and BAT of both phospholipids and glycerol lipids in response to exercise training, thus providing a comprehensive resource for future studies of lipid metabolism pathways.

LDRD final report on adaptive-responsive nanostructures for sensing applications.

Energy Technology Data Exchange (ETDEWEB)

Shelnutt, John Allen; van Swol, Frank B.; Wang, Zhongchun; Medforth, Craig J.

2005-11-01

Functional organic nanostructures such as well-formed tubes or fibers that can easily be fabricated into electronic and photonic devices are needed in many applications. Especially desirable from a national security standpoint are nanostructures that have enhanced sensitivity for the detection of chemicals and biological (CB) agents and other environmental stimuli. We recently discovered the first class of highly responsive and adaptive porphyrin-based nanostructures that may satisfy these requirements. These novel porphyrin nanostructures, which are formed by ionic self-assembly of two oppositely charged porphyrins, may function as conductors, semiconductors, or photoconductors, and they have additional properties that make them suitable for device fabrication (e.g., as ultrasensitive colorimetric CB microsensors). Preliminary studies with porphyrin nanotubes have shown that these nanostructures have novel optical and electronic properties, including strong resonant light scattering, quenched fluorescence, and electrical conductivity. In addition, they are photochemically active and capable of light-harvesting and photosynthesis; they may also have nonlinear optical properties. Remarkably, the nanotubes and potentially other porphyrin nanostructure are mechanically responsive and adaptive (e.g., the rigidity of the micrometers-long nanotubes is altered by light, ultrasound, or chemicals) and they self-heal upon removal the environmental stimulus. Given the tremendous degree of structural variation possible in the porphyrin subunits, additional types of nanostructures and greater control over their morphology can be anticipated. Molecular modification also provides a means of controlling their electronic, photonic, and other functional properties. In this work, we have greatly broadened the range of ionic porphyrin nanostructures that can be made, and determined the optical and responsivity properties of the nanotubes and other porphyrin nanostructures. We have

Fluid intelligence and neural mechanisms of conflict adaptation

DEFF Research Database (Denmark)

Liu, Tongran; Xiao, Tong; Jiannong, Shi

2016-01-01

The current study investigated whether adolescents with different intellectual levels have different conflict adaptation processes. Adolescents with high and average IQ abilities were enrolled, and their behavioral responses and event-related potentials (ERPs) were recorded during a modified...... Eriksen flanker task. Both groups showed reliable conflict adaptation effects (CAE) with regard to the reaction time (RT), and they showed a faster response to the cC condition than to the iC condition and faster response to the iI condition than to the cI condition. The IQ-related findings showed...... that high IQ adolescents had shorter RTs than their average-IQ counterparts in the cI, iC, and iI conditions, with smaller RT-CAE values. These findings indicated that high IQ adolescents had superior conflict adaptation processes. The electrophysiological findings showed that the cI condition required more...

Stochastic analysis of epidemics on adaptive time varying networks

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Kotnis, Bhushan; Kuri, Joy

2013-06-01

Many studies investigating the effect of human social connectivity structures (networks) and human behavioral adaptations on the spread of infectious diseases have assumed either a static connectivity structure or a network which adapts itself in response to the epidemic (adaptive networks). However, human social connections are inherently dynamic or time varying. Furthermore, the spread of many infectious diseases occur on a time scale comparable to the time scale of the evolving network structure. Here we aim to quantify the effect of human behavioral adaptations on the spread of asymptomatic infectious diseases on time varying networks. We perform a full stochastic analysis using a continuous time Markov chain approach for calculating the outbreak probability, mean epidemic duration, epidemic reemergence probability, etc. Additionally, we use mean-field theory for calculating epidemic thresholds. Theoretical predictions are verified using extensive simulations. Our studies have uncovered the existence of an “adaptive threshold,” i.e., when the ratio of susceptibility (or infectivity) rate to recovery rate is below the threshold value, adaptive behavior can prevent the epidemic. However, if it is above the threshold, no amount of behavioral adaptations can prevent the epidemic. Our analyses suggest that the interaction patterns of the infected population play a major role in sustaining the epidemic. Our results have implications on epidemic containment policies, as awareness campaigns and human behavioral responses can be effective only if the interaction levels of the infected populace are kept in check.

Adaptive response of the chicken embryo to low doses of x-irradiation

International Nuclear Information System (INIS)

Tempel, K.; Schleifer, S.

1995-01-01

Chicken embryos were x-irradiated in ovo with 5-30 cGy (=priming dose) at the 13th-15th day of development. After 3-48 h, brain- and liver-cell suspensions were x-irradiated in vitro with (challenge) doses of 4-32 Gy. Significantly less radiation damage was observed when the radiation response was measured by scheduled DNA synthesis, nucleoid sedimentation and viscosity of alkaline cell lysates 12-36 h after the priming exposure. In vivo, pre-irradiation with 10 cGy enhanced regeneration as evidenced by the DNA content of chicken embryo brain and liver 24 h following a challenge dose of 4 Gy. From nucleoid sedimentation analyses in brain and liver cells immediately after irradiation with 16 Gy and after a 30-min repair period in the presence of aphidicolin, dideoxythymidine and 3-aminobenzamide or in the absence of these DNA repair inhibitors, it is concluded that a reduction of the initial radiation damage is the dominant mechanism of the ''radio-adaptive'' response of the chicken embryo. Sedimentation of nucleoids from ethidium bromide (EB) (0.75-400 μg/ml)-treated cells suggests a higher tendency of ''radio-adapted'' cells to undergo positive DNA supercoiling in the presence of high EB concentrations. (orig.)

Adaptive Controller Effects on Pilot Behavior

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Trujillo, Anna C.; Gregory, Irene M.; Hempley, Lucas E.

2014-01-01

Adaptive control provides robustness and resilience for highly uncertain, and potentially unpredictable, flight dynamics characteristic. Some of the recent flight experiences of pilot-in-the-loop with an adaptive controller have exhibited unpredicted interactions. In retrospect, this is not surprising once it is realized that there are now two adaptive controllers interacting, the software adaptive control system and the pilot. An experiment was conducted to categorize these interactions on the pilot with an adaptive controller during control surface failures. One of the objectives of this experiment was to determine how the adaptation time of the controller affects pilots. The pitch and roll errors, and stick input increased for increasing adaptation time and during the segment when the adaptive controller was adapting. Not surprisingly, altitude, cross track and angle deviations, and vertical velocity also increase during the failure and then slowly return to pre-failure levels. Subjects may change their behavior even as an adaptive controller is adapting with additional stick inputs. Therefore, the adaptive controller should adapt as fast as possible to minimize flight track errors. This will minimize undesirable interactions between the pilot and the adaptive controller and maintain maneuvering precision.

Adaptive Activation of a Stress Response Pathway Improves Learning and Memory Through Gs and β-Arrestin-1-Regulated Lactate Metabolism.

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Dong, Jun-Hong; Wang, Yi-Jing; Cui, Min; Wang, Xiao-Jing; Zheng, Wen-Shuai; Ma, Ming-Liang; Yang, Fan; He, Dong-Fang; Hu, Qiao-Xia; Zhang, Dao-Lai; Ning, Shang-Lei; Liu, Chun-Hua; Wang, Chuan; Wang, Yue; Li, Xiang-Yao; Yi, Fan; Lin, Amy; Kahsai, Alem W; Cahill, Thomas Joseph; Chen, Zhe-Yu; Yu, Xiao; Sun, Jin-Peng

2017-04-15

Stress is a conserved physiological response in mammals. Whereas moderate stress strengthens memory to improve reactions to previously experienced difficult situations, too much stress is harmful. We used specific β-adrenergic agonists, as well as β 2 -adrenergic receptor (β2AR) and arrestin knockout models, to study the effects of adaptive β2AR activation on cognitive function using Morris water maze and object recognition experiments. We used molecular and cell biological approaches to elucidate the signaling subnetworks. We observed that the duration of the adaptive β2AR activation determines its consequences on learning and memory. Short-term formoterol treatment, for 3 to 5 days, improved cognitive function; however, prolonged β2AR activation, for more than 6 days, produced harmful effects. We identified the activation of several signaling networks downstream of β2AR, as well as an essential role for arrestin and lactate metabolism in promoting cognitive ability. Whereas Gs-protein kinase A-cyclic adenosine monophosphate response element binding protein signaling modulated monocarboxylate transporter 1 expression, β-arrestin-1 controlled expression levels of monocarboxylate transporter 4 and lactate dehydrogenase A through the formation of a β-arrestin-1/phospho-mitogen-activated protein kinase/hypoxia-inducible factor-1α ternary complex to upregulate lactate metabolism in astrocyte-derived U251 cells. Conversely, long-term treatment with formoterol led to the desensitization of β2ARs, which was responsible for its decreased beneficial effects. Our results not only revealed that β-arrestin-1 regulated lactate metabolism to contribute to β2AR functions in improved memory formation, but also indicated that the appropriate management of one specific stress pathway, such as through the clinical drug formoterol, may exert beneficial effects on cognitive abilities. Copyright © 2016 Society of Biological Psychiatry. All rights reserved.

The innate and adaptive immune response induced by alveolar macrophages exposed to ambient particulate matter

International Nuclear Information System (INIS)

Miyata, Ryohei; Eeden, Stephan F. van

2011-01-01

Emerging epidemiological evidence suggests that exposure to particulate matter (PM) air pollution increases the risk of cardiovascular events but the exact mechanism by which PM has adverse effects is still unclear. Alveolar macrophages (AM) play a major role in clearing and processing inhaled PM. This comprehensive review of research findings on immunological interactions between AM and PM provides potential pathophysiological pathways that interconnect PM exposure with adverse cardiovascular effects. Coarse particles (10 μm or less, PM 10 ) induce innate immune responses via endotoxin-toll-like receptor (TLR) 4 pathway while fine (2.5 μm or less, PM 2.5 ) and ultrafine particles (0.1 μm or less, UFP) induce via reactive oxygen species generation by transition metals and/or polyaromatic hydrocarbons. The innate immune responses are characterized by activation of transcription factors [nuclear factor (NF)-κB and activator protein-1] and the downstream proinflammatory cytokine [interleukin (IL)-1β, IL-6, and tumor necrosis factor-α] production. In addition to the conventional opsonin-dependent phagocytosis by AM, PM can also be endocytosed by an opsonin-independent pathway via scavenger receptors. Activation of scavenger receptors negatively regulates the TLR4-NF-κB pathway. Internalized particles are subsequently subjected to adaptive immunity involving major histocompatibility complex class II (MHC II) expression, recruitment of costimulatory molecules, and the modulation of the T helper (Th) responses. AM show atypical antigen presenting cell maturation in which phagocytic activity decreases while both MHC II and costimulatory molecules remain unaltered. PM drives AM towards a Th1 profile but secondary responses in a Th1- or Th-2 up-regulated milieu drive the response in favor of a Th2 profile.

The neural response properties and cortical organization of a rapidly adapting muscle sensory group response that overlaps with the frequencies that elicit the kinesthetic illusion.

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Paul D Marasco

Full Text Available Kinesthesia is the sense of limb movement. It is fundamental to efficient motor control, yet its neurophysiological components remain poorly understood. The contributions of primary muscle spindles and cutaneous afferents to the kinesthetic sense have been well studied; however, potential contributions from muscle sensory group responses that are different than the muscle spindles have not been ruled out. Electrophysiological recordings in peripheral nerves and brains of male Sprague Dawley rats with a degloved forelimb preparation provide evidence of a rapidly adapting muscle sensory group response that overlaps with vibratory inputs known to generate illusionary perceptions of limb movement in humans (kinesthetic illusion. This group was characteristically distinct from type Ia muscle spindle fibers, the receptor historically attributed to limb movement sensation, suggesting that type Ia muscle spindle fibers may not be the sole carrier of kinesthetic information. The sensory-neural structure of muscles is complex and there are a number of possible sources for this response group; with Golgi tendon organs being the most likely candidate. The rapidly adapting muscle sensory group response projected to proprioceptive brain regions, the rodent homolog of cortical area 3a and the second somatosensory area (S2, with similar adaption and frequency response profiles between the brain and peripheral nerves. Their representational organization was muscle-specific (myocentric and magnified for proximal and multi-articulate limb joints. Projection to proprioceptive brain areas, myocentric representational magnification of muscles prone to movement error, overlap with illusionary vibrational input, and resonant frequencies of volitional motor unit contraction suggest that this group response may be involved with limb movement processing.

What kind of prior low dose radiation does the adaptive response induce?

International Nuclear Information System (INIS)

Suzuki, Masao

2009-01-01

Described are the adaptive response (AR) and genetic instability (GI) induced by different kind of low dose radiation (LDR) and their relation with the bystander effect. For this, human normal cells were placed at 2.65 m distance from the target of National Institute of Radiological Sciences (NIRS) Heavy Ion Medical Accelerator in Chiba (HIMAC) to see the biological effect of LDR of mixed radiations (1-1.5 mGy/day; mixture of 94% gamma ray, 1.9% neutron (N) and particle ions mainly containing proton (P) in the rest). Cells were then irradiated with 1.5 Gy X-ray. No effect on the lethality was observed as compared with control cells without LDR. The mutation on hprt gene was found significantly elevated 2-30 days after LDR, suggesting that GI had been induced. To see the effect of each radiation on GI, gamma ray ( 137 Cs), N ( 241 Am-Be) and heavy ion (HIMAC He, C and Fe) as LDR were separately irradiated to cells with total 1 mGy/7-8 hr and then acutely with the X-ray. He and C ions were found to promote mutation 1.9 and 4.0 times higher on frequencies, respectively, and N, to reduce the mutation rate to 15% (AR). Results indicated that cell responses were quite different dependently on linear energy transfer. The probability of hit number of ions in the cell population was calculated to be 61, 15 and 2% for He, C and Fe, respectively, suggesting an existence of considerable number of cells not irradiated. Presence of a gap-junction specific inhibitor (GSI) at LDR resulted in normalization of mutation rate in all groups of cells, suggesting that the bystander effect through cell-cell signal transduction affected the cell response to X-irradiation. For AR induction by N, when 1.5% of cells in culture were irradiated by P in NIRS SPICE as LDR, AR in mutation was observed and was inhibited by GSI, suggesting that N completely destroyed the hit cell but concomitantly yielded recoil P substantially acted as LDR. Above findings indicated that the exact radiation risk can

Meditation-induced cognitive-control states regulate response-conflict adaptation: Evidence from trial-to-trial adjustments in the Simon task.

Science.gov (United States)

Colzato, Lorenza S; Sellaro, Roberta; Samara, Iliana; Hommel, Bernhard

2015-09-01

Here we consider the possibility that meditation has an immediate impact on information processing. Moreover, we were interested to see whether this impact affects attentional input control, as previous observations suggest, or the handling of response conflict. Healthy adults underwent a brief single session of either focused attention meditation (FAM), which is assumed to increase top-down control, or open monitoring meditation (OMM), which is assumed to weaken top-down control, before performing a Simon task-which assesses conflict-resolution efficiency. While the size of the Simon effect (reflecting the efficiency of handling response conflict) was unaffected by type of meditation, the amount of dynamic behavioral adjustments (i.e., trial-to-trial variability of the Simon effect: the Gratton effect) was considerably smaller after OMM than after FAM. Our findings suggest that engaging in meditation instantly creates a cognitive-control state that has a specific impact on conflict-driven control adaptations. Copyright © 2015 Elsevier Inc. All rights reserved.

Principles of exercise physiology: responses to acute exercise and long-term adaptations to training.

Science.gov (United States)

Rivera-Brown, Anita M; Frontera, Walter R

2012-11-01

Physical activity and fitness are associated with a lower prevalence of chronic diseases, such as heart disease, cancer, high blood pressure, and diabetes. This review discusses the body's response to an acute bout of exercise and long-term physiological adaptations to exercise training with an emphasis on endurance exercise. An overview is provided of skeletal muscle actions, muscle fiber types, and the major metabolic pathways involved in energy production. The importance of adequate fluid intake during exercise sessions to prevent impairments induced by dehydration on endurance exercise, muscular power, and strength is discussed. Physiological adaptations that result from regular exercise training such as increases in cardiorespiratory capacity and strength are mentioned. The review emphasizes the cardiovascular and metabolic adaptations that lead to improvements in maximal oxygen capacity. Copyright © 2012 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Training and Transfer Effects of Response Inhibition Training in Children and Adults

Science.gov (United States)

Zhao, Xin; Chen, Ling; Maes, Joseph H. R.

2018-01-01

Response inhibition is crucial for mental and physical health but studies assessing the trainability of this type of inhibition are rare. Thirty-nine children aged 10-12 years and 46 adults aged 18-24 years were assigned to an adaptive go/no-go inhibition training condition or an active control condition. Transfer of training effects to…

A stressful microenvironment: opposing effects of the endoplasmic reticulum stress response in the suppression and enhancement of adaptive tumor immunity.

Science.gov (United States)

Rausch, Matthew P; Sertil, Aparna Ranganathan

2015-03-01

The recent clinical success of immunotherapy in the treatment of certain types of cancer has demonstrated the powerful ability of the immune system to control tumor growth, leading to significantly improved patient survival. However, despite these promising results current immunotherapeutic strategies are still limited and have not yet achieved broad acceptance outside the context of metastatic melanoma. The limitations of current immunotherapeutic approaches can be attributed in part to suppressive mechanisms present in the tumor microenvironment that hamper the generation of robust antitumor immune responses thus allowing tumor cells to escape immune-mediated destruction. The endoplasmic reticulum (ER) stress response has recently emerged as a potent regulator of tumor immunity. The ER stress response is an adaptive mechanism that allows tumor cells to survive in the harsh growth conditions inherent to the tumor milieu such as low oxygen (hypoxia), low pH and low levels of glucose. Activation of ER stress can also alter the cancer cell response to therapies. In addition, the ER stress response promotes tumor immune evasion by inducing the production of protumorigenic inflammatory cytokines and impairing tumor antigen presentation. However, the ER stress response can boost antitumor immunity in some situations by enhancing the processing and presentation of tumor antigens and by inducing the release of immunogenic factors from stressed tumor cells. Here, we discuss the dualistic role of the ER stress response in the modulation of tumor immunity and highlight how strategies to either induce or block ER stress can be employed to improve the clinical efficacy of tumor immunotherapy.

FORMATION OF INNATE AND ADAPTIVE IMMUNE RESPONSE UNDER THE INFLUENCE OF DIFFERENT FLAVIVIRUS VACCINES

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N. V. Krylova

2015-01-01

Full Text Available The review examines in a comparative perspective the key moments of formation of innate and adaptive immune responses to different types of current flavivirus vaccines: live attenuated against yellow fever virus and inactivated whole virus against tick-borne encephalitis virus. Particular attention is paid to the ability of these different vaccines, containing exogenous pathogen-associated molecular structures, to stimulate innate immunity. Live attenuated vaccine by infecting several subtypes of dendritic cells activates them through various pattern-recognition receptors, such as Tolland RIG-I-like receptors, which leads to significant production of proinflammatory cytokines, including interferon-α primary mediator of innate antiviral immunity. By simulating natural viral infection, this vaccine quickly spreads over the vascular network, and the dendritic cells, activated by it, migrate to the draining lymph nodes and trigger multiple foci of Tand B-cell activation. Inactivated vaccine stimulates the innate immunity predominantly at the injection site, and for the sufficient activation requires the presence in its composition of an adjuvant (aluminum hydroxide, which effects the formation and activation of inflammasomes, ensuring the formation and secretion of IL-1β and IL-18 that, in turn, trigger a cascade of cellular and humoral innate immune responses. We demonstrated the possibility of involvement in the induction of innate immunity, mediated by the inactivated vaccine, endogenous pathogenassociated molecular patterns (uric acid and host cell DNA, forming at the vaccine injection site. We discuss the triggering of Band T-cell responses by flavivirus vaccines that determine various duration of protection against various pathogens. A single injection of the live vaccine against yellow fever virus induces polyvalent adaptive immune response, including the production of cytotoxic T-lymphocytes, Th1and Th2-cells and neutralizing antibodies

Adaptive response of spermatogenic cell apoptosis selectively induced by low dose X-ray irradiation in mice

International Nuclear Information System (INIS)

Liu Guangwei; Dong Lihua; Liu Yang; Lv Zhe; Liu Shuchun; Gong Shouliang

2003-01-01

Objective: The adaptive response of spermatogenic cell apoptosis induced by whole-body X-ray irradiation at low doses was studied in mice. Methods: Kunming male mice were irradiated with an inductive dose (D1:75 mGy) and/or a challenging dose (D2:1.0, 2.0 or 3.0 Gy). Different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptotic percentages were analysed using flow cytometry (FCM). Results: When the mice were irradiated with D1 6 h before irradiation with D2, the apoptotic percentages of the spermatogonia and spermatocytes declined rapidly as compared with those in the groups irradiated with D2 only, and those of spermatids and spermatozoa showed no significant changes. When the interval times between D1 and D2 was 3, 6, 12 or 24 h, the apoptotic percentages in spermatogonia and spermatocytes reduced early, significantly and continued for a longer duration after smaller D2(1.0 and 2.0 Gy) irradiation, while the apoptotic percentages did not change after larger D2(3.0 Gy) irradiation. Conclusion: The adaptive response of apoptosis in spermatogonia and spermatocytes could be selectively induced by low dose X-ray irradiation. The adaptive response could be closely related to the D2 dose and interval time between D1 and D2

Guiding climate change adaptation within vulnerable natural resource management systems.

Science.gov (United States)

Bardsley, Douglas K; Sweeney, Susan M

2010-05-01

Climate change has the potential to compromise the sustainability of natural resources in Mediterranean climatic systems, such that short-term reactive responses will increasingly be insufficient to ensure effective management. There is a simultaneous need for both the clear articulation of the vulnerabilities of specific management systems to climate risk, and the development of appropriate short- and long-term strategic planning responses that anticipate environmental change or allow for sustainable adaptive management in response to trends in resource condition. Governments are developing climate change adaptation policy frameworks, but without the recognition of the importance of responding strategically, regional stakeholders will struggle to manage future climate risk. In a partnership between the South Australian Government, the Adelaide and Mt Lofty Ranges Natural Resource Management Board and the regional community, a range of available research approaches to support regional climate change adaptation decision-making, were applied and critically examined, including: scenario modelling; applied and participatory Geographical Information Systems modelling; environmental risk analysis; and participatory action learning. As managers apply ideas for adaptation within their own biophysical and socio-cultural contexts, there would be both successes and failures, but a learning orientation to societal change will enable improvements over time. A base-line target for regional responses to climate change is the ownership of the issue by stakeholders, which leads to an acceptance that effective actions to adapt are now both possible and vitally important. Beyond such baseline knowledge, the research suggests that there is a range of tools from the social and physical sciences available to guide adaptation decision-making.

Guiding Climate Change Adaptation Within Vulnerable Natural Resource Management Systems

Science.gov (United States)

Bardsley, Douglas K.; Sweeney, Susan M.

2010-05-01

Climate change has the potential to compromise the sustainability of natural resources in Mediterranean climatic systems, such that short-term reactive responses will increasingly be insufficient to ensure effective management. There is a simultaneous need for both the clear articulation of the vulnerabilities of specific management systems to climate risk, and the development of appropriate short- and long-term strategic planning responses that anticipate environmental change or allow for sustainable adaptive management in response to trends in resource condition. Governments are developing climate change adaptation policy frameworks, but without the recognition of the importance of responding strategically, regional stakeholders will struggle to manage future climate risk. In a partnership between the South Australian Government, the Adelaide and Mt Lofty Ranges Natural Resource Management Board and the regional community, a range of available research approaches to support regional climate change adaptation decision-making, were applied and critically examined, including: scenario modelling; applied and participatory Geographical Information Systems modelling; environmental risk analysis; and participatory action learning. As managers apply ideas for adaptation within their own biophysical and socio-cultural contexts, there would be both successes and failures, but a learning orientation to societal change will enable improvements over time. A base-line target for regional responses to climate change is the ownership of the issue by stakeholders, which leads to an acceptance that effective actions to adapt are now both possible and vitally important. Beyond such baseline knowledge, the research suggests that there is a range of tools from the social and physical sciences available to guide adaptation decision-making.

What You See is what You Just Heard: The Effect of Temporal Rate Adaptation on Human Intersensory Perception

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Carmel Levitan

2011-10-01

Full Text Available Previous studies on perception have yet to establish that psychophysical adaptation effects transfer from one sense to another. To test for this phenomenon, the current study examines the possible crossmodal transfer of temporal rate adaptation from vision to audition (VA and from audition to vision (AV. Participants were trained, using feedback, to discriminate the perceived rapidity of either auditory or visual stimuli presented at a range of randomly-ordered frequencies (3.25–4.75 Hz as compared to that of stimuli (of the same modality at a familiar average frequency (4 Hz. Afterwards, subjects were repeatedly exposed to stimuli (of the other modality at a specific rate (3 Hz or 5 Hz. To test whether adaptation resulted from this exposure, subjects again completed the task previously used for training, but now without feedback. After the initial training and adaptation phases, these test and adaptation tasks were presented in 20 alternating blocks. A comparison of the pre- and post-adaptation responses showed crossmodal changes in subjects' perception of temporal rate, such that adaptation to 5 Hz led to the subsequent stimuli seeming slower than they had before adaptation. On the other hand, after exposure to 3 Hz stimuli, the opposite effect was seen. This shift occurred in both VA and AV conditions. As audition and vision were never simultaneously presented, this is suggestive of a strong linkage between the two modalities in perceiving rate. We propose that this is due to the presence of early, distributed, within-modal clocks, that can vigorously modulate each other cross-modally.

Radiation-induced adaptive response in human lymphoblast

International Nuclear Information System (INIS)

Yatagai, Fumio; Sugasawa, Kaoru

2009-01-01

Described are the genetic analysis of variant strains obtained by the optimal condition for radiation-induced adaptive response (AR), and molecular elucidation of the suppression of concomitant mutation. The TK6 cells (heterozygous thymidine kinase, +/-) were used for detection of mutation by loss of heterozygosity (LOH). The optimal conditions for reducing the mutation by subsequent irradiation (SI) to its rate of about 60% (vs control 100%, no PI) were found to be 5 cGy of pre-irradiation (PI) of X-ray and 2 Gy of SI with the interval of 6 hr, where mutated cells were of non-LOH type in around 25% and homo-LOH type by homologous recombination (HR) in 60%. By cDNA sequencing, the former cells having changed bases were found to be in variant strain ratio of 1/8 vs control 7/18, suggesting that the mutation was decreased mainly by suppression of base change. Expression of XPC protein, an important component for recognition of the base damage in global genome nucleotide excision repair, was studied by Western blotting as the possible mechanism of suppressing the mutation, which revealed different time dynamics of the protein in cells with PI+SI and SI alone (control). To see the effect of PI on the double strand break (DSB) repair, cells with PI were infected with restriction enzyme I-SceI vector to yield DSB instead of SI, which revealed more efficient repair (70% increase) by HR than control, without significant difference in non-homologous end-joining repair. Micro-array analysis to study the gene expression in the present experimental conditions for AR is in progress. The TK6 cells used here were thought useful for additional studies of the mechanism of AR as mutation by direct or indirect irradiation can be tested. (K.T.)

Artificial Selection Response due to Polygenic Adaptation from a Multilocus, Multiallelic Genetic Architecture.

Science.gov (United States)

Zan, Yanjun; Sheng, Zheya; Lillie, Mette; Rönnegård, Lars; Honaker, Christa F; Siegel, Paul B; Carlborg, Örjan

2017-10-01

The ability of a population to adapt to changes in their living conditions, whether in nature or captivity, often depends on polymorphisms in multiple genes across the genome. In-depth studies of such polygenic adaptations are difficult in natural populations, but can be approached using the resources provided by artificial selection experiments. Here, we dissect the genetic mechanisms involved in long-term selection responses of the Virginia chicken lines, populations that after 40 generations of divergent selection for 56-day body weight display a 9-fold difference in the selected trait. In the F15 generation of an intercross between the divergent lines, 20 loci explained >60% of the additive genetic variance for the selected trait. We focused particularly on fine-mapping seven major QTL that replicated in this population and found that only two fine-mapped to single, bi-allelic loci; the other five contained linked loci, multiple alleles or were epistatic. This detailed dissection of the polygenic adaptations in the Virginia lines provides a deeper understanding of the range of different genome-wide mechanisms that have been involved in these long-term selection responses. The results illustrate that the genetic architecture of a highly polygenic trait can involve a broad range of genetic mechanisms, and that this can be the case even in a small population bred from founders with limited genetic diversity. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evasion of adaptive and innate immune response mechanisms by γ-herpesviruses

Science.gov (United States)

Feng, Pinghui; Moses, Ashlee; Früh, Klaus

2015-01-01

γ-Herpesviral immune evasion mechanisms are optimized to support the acute, lytic and the longterm, latent phase of infection. During acute infection, specific immune modulatory proteins limit, but also exploit, the antiviral activities of cell intrinsic innate immune responses as well as those of innate and adaptive immune cells. During latent infection, a restricted gene expression program limits immune targeting and cis-acting mechanisms to reduce the antigen presentation as well as antigenicity of latency-associated proteins. Here, we will review recent progress in our understanding of γ-herpesviral immune evasion strategies. PMID:23735334

The effect of aging on the dynamics of reactive and proactive cognitive control of response interference

Directory of Open Access Journals (Sweden)

Ling Xiang

2016-11-01

Full Text Available A prime-target interference task was used to investigate the effects of cognitive aging on reactive and proactive control in which frequency confounds and feature repetitions were eliminated from the cognitive control measures. We used distributional analyses to explore the dynamics of the two control functions by distinguishing the strength of incorrect response capture and the efficiency of suppression control. For reactive control, within-trial conflict control and between-trial conflict adaption were analyzed. The statistical analysis showed that there were no reliable between-trial conflict adaption effects for both young and older adults. For within-trial conflict control, the results revealed that older adults showed larger interference effects on mean RT and mean accuracy. Distributional analyses showed that the decline mainly stemmed from inefficient suppression rather than from stronger incorrect responses. For proactive control, older adults showed comparable proactive conflict resolution than young adults on mean RT and mean accuracy. Distributional analyses showed older adults were as effective as younger adults in adjusting their responses to minimize automatic response capture and actively suppress the direct response activation based on congruency proportion information. The results suggest that older adults were less proficient at suppressing interference after conflict was detected but can anticipate and prevent inference in response to congruency proportion manipulation. The results challenge earlier views that older adults have selective deficits in proactive control but are spared in reactive control.

Common-but-differentiated-Responsibilities for adaptation financing. An assessment of the contributions of countries

Energy Technology Data Exchange (ETDEWEB)

Dellink, R. [Wageningen University, Wageningen (Netherlands); Den Elzen, M. [Netherlands Environmental Assessment Agency NMP, Bilthoven (Netherlands); Aikinga, H.; Bergsm, E.; Berkhout, F.; Dekker, T.; Gupta, J. [Institute for Environmental Studies IVM, VU University, Amsterdam (Netherlands)

2009-03-15

Climate change may cause most harm to countries that have historically contributed the least to greenhouse gas emissions and land-use change. This paper identifies deontology, solidarity and consequentialism as the principles that can serve as a basis for a fair international burden sharing scheme of climate change adaptation costs. We translate these principles into criteria that can be applied in assigning a share of the financial burden to individual countries, namely historical responsibility, equality and capacity to pay. Specific political and scientific choices are discussed, highlighting implications for international burden-sharing schemes. A hybrid approach, combining historical responsibility and capacity to pay seems a promising starting point for international negotiations on the design of burden-sharing schemes. From the numerical assessment, it is clear that UNFCCC Annex I countries carry the greatest burden under most scenarios, but contributions differ substantially subject to the choice of an indicator for capacity to pay. The contributions are less sensitive to choices related to responsibility calculations, apart from those associated with land-use related emissions. Assuming the costs of climate adaptation are USD100 billion per year, the total financial contribution by the Annex I countries would be in the range of USD 55-68 billion per year.

Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates.

Science.gov (United States)

Storz, Jay F; Scott, Graham R; Cheviron, Zachary A

2010-12-15

High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change.

[Vasoprotective effect of adaptation to hypoxia in myocardial ischemia and reperfusion injury].

Science.gov (United States)

Manukhina, E B; Terekhina, O L; Belkina, L M; Abramochkin, D V; Budanova, O P; Mashina, S Yu; Smirin, B V; Yakunina, E B; Downey, H F

2013-01-01

Adaptation to hypoxia is known to be cardioprotective in ischemic and reperfusion (IR) injury of the myocardium. This study was focused on investigating a possibility for prevention of endothelial dysfunction in IR injury of the rat heart using adaptation to intermittent hypoxia, which was performed in a cyclic mode (5-10 min of hypoxia interspersed with 4 min of normoxia, 5-8 cycles daily) for 21 days. Endothelial function of coronary blood vessels was evaluated after the in vitro IR of isolated heart (15 min of ischemia and 10 min of reperfusion) by the increment of coronary flow rate in response to acetylcholine. Endothelium-dependent relaxation of isolated rat aorta was evaluated after the IR myocardial injury in situ (30 min of ischemia and 60 min of reperfusion) by a relaxation response of noradrenaline-precontracted vessel rings to acetylcholine. The following major results were obtained in this study: 1) IR myocardial injury induced endothelial dysfunction of coronary blood vessels and the aorta, a non-coronary blood vessel, remote from the IR injury area; and 2) adaptation to hypoxia prevented the endothelial dysfunction of both coronary and non-coronary blood vessels associated with the IR injury. Therefore, adaptation to hypoxia is not only cardioprotective but also vasoprotective in myocardial IR injury.

Automatic change detection in vision: Adaptation, memory mismatch, or both? II: Oddball and adaptation effects on event-related potentials.

Science.gov (United States)

Bodnár, Flóra; File, Domonkos; Sulykos, István; Kecskés-Kovács, Krisztina; Czigler, István

2017-11-01

In this study we compared the event-related potentials (ERPs) obtained in two different paradigms: a passive visual oddball paradigm and an adaptation paradigm. The aim of the study was to investigate the relation between the effects of activity decrease following an adaptor (stimulus-specific adaptation) and the effects of an infrequent stimulus within sequences of frequent ones. In Experiment 1, participants were presented with different line textures. The frequent (standard) and rare (deviant) texture elements differed in their orientation. In Experiment 2, windmill pattern stimuli were presented in which the number of vanes differentiated the deviant and standard stimuli. In Experiment 1 the ERP differences elicited between the oddball deviant and the standard were similar to the differences between the ERPs to the nonadapted and adapted stimuli in the adaptation paradigm. In both paradigms the differences appeared as a posterior negativity with the latency of 120-140 ms. This finding demonstrates that the representation of a sequential rule (successive presentation of the standard) and the violation of this rule are not necessary for deviancy effects to emerge. In Experiment 2 (windmill pattern), in the oddball paradigm the difference potentials appeared as a long-lasting negativity. In the adaptation condition, the later part of this negativity (after 200 ms) was absent. We identified the later part of the oddball difference potential as the genuine visual mismatch negativity-that is, an ERP correlate of sequence violations. The latencies of the difference potentials (deviant minus standard) and the endogenous components (P1 and N1) diverged; therefore, the adaptation of these particular ERP components cannot explain the deviancy effect. Accordingly, the sources contributing to the standard-versus-deviant modulations differed from those related to visual adaptation; that is, they generated distinct ERP components.

Adapting to the effects of climate change [Chapter 14

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Jessica E. Halofsky

2018-01-01

Adapting to climate change, or adjusting to current or future climate and its effects (Noble et al. 2014), is critical to minimizing the risks associated with climate change impacts. Adaptation actions can vary from passive (e.g., a "wait and see" approach), to relatively simple (e.g., increasing harvest rotation age), to complex (e.g., managing forest...

Conflict adaptation in patients diagnosed with schizophrenia.

Science.gov (United States)

Abrahamse, Elger; Ruitenberg, Marit; Boddewyn, Sarah; Oreel, Edith; de Schryver, Maarten; Morrens, Manuel; van Dijck, Jean-Philippe

2017-11-01

Cognitive control impairments may contribute strongly to the overall cognitive deficits observed in patients diagnosed with schizophrenia. In the current study we explore a specific cognitive control function referred to as conflict adaptation. Previous studies on conflict adaptation in schizophrenia showed equivocal results, and, moreover, were plagued by confounded research designs. Here we assessed for the first time conflict adaptation in schizophrenia with a design that avoided the major confounds of feature integration and stimulus-response contingency learning. Sixteen patients diagnosed with schizophrenia and sixteen healthy, matched controls performed a vocal Stroop task to determine the congruency sequence effect - a marker of conflict adaptation. A reliable congruency sequence effect was observed for both healthy controls and patients diagnosed with schizophrenia. These findings indicate that schizophrenia is not necessarily accompanied by impaired conflict adaptation. As schizophrenia has been related to abnormal functioning in core conflict adaptation areas such as anterior cingulate and dorsolateral prefrontal cortex, further research is required to better understand the precise impact of such abnormal brain functioning at the behavioral level. Copyright © 2017 Elsevier B.V. All rights reserved.

Does individual responsibility increase the adaptive capacity of society? The case of local water management in the Netherlands

NARCIS (Netherlands)

Bergsma, E.; Gupta, J.; Jong, P.

2012-01-01

In different parts of the world, neo-liberal politics is shifting responsibilities from the nation state to other governmental and non-governmental actors. This is also evident in the governance of adaptation to the impacts of climate change, where the responsibility of the individual is

Effect of Eight Weeks of Resistance Exercise on Adaptive Responses of Cortisol and Androgens in Postmenopausal Women

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R Zare

2016-05-01

Full Text Available Introduction: Decreased anabolic to catabolic ratio during menopause, can lead to a reduction in muscle size and strength. Hence, the current study amed to investigate the effect of eight weeks of resistance exercise on adaptive responses of cortisol and androgens in postmenopausal women. Methods: In this semi-experimental study, 16 healthy postmenopausal women with the age range of 48 to 62 years and a body mass index greater than 25 kg/m2 were selected (via paposeful and convenience sampling who participated in an eight-week program of circular shape resistance training (8 stations, 3 sets with 12 repeatation with intensity of 65-40% of one repetition maximum. Serum levels of testosterone, dehydroepiandrosterone sulfate, and cortisol were measured 48 hours before and after the intervention. The study data were analyzed by paired student’s t-test at a significance level of P<0.05. Results: The study results following resistance training, dehydroepiandrosterone sulfate levels (58%, P=0.000, testosterone (71%, P=0.017, testosterone to cortisol ratio (125%, P=0.016 and dehydroepiandrosterone sulfate to cortisol ratio (61%, P=0.002 significantly increased. Although the amount of post-test cortisol levels was decreased, this change was not held to be significant (P=0.459. Conclusion: Eight weeks of resistance training leads to a significant increase in levels of androgens as well as androgens to cortisol ratio. Therefore, resistance training by increasing the ratio of anabolic to catabolic hormones can prevente muscle size and strength, and aid to wellbeing and health of postmenopausal women.

Indications of an adaptive response in C57bl mice pre-exposed in vivo to low doses of ionizing radiation

International Nuclear Information System (INIS)

Wojcik, A.; Tuschl, H.

1989-08-01

C57bl/6 mice were whole body irradiated with 50 mGy/day ('adapting dose') on four consecutive days and their spleens removed on the 1 st , 3 rd , 7 th , 12 th , 19 th , and 26 th day after the last irradiation. In vitro UV-light-induced UDS and MMC-induced SCEs were scored in lymphocytes, UV-light and MMC being the 'challenging agents' yielding higher UDS values and lower frequencies of induced SCEs than in cells of nonadapted animals. On day 12 this effect could only be seen in half, on day 19 and 26 in none of the performed experiments. The results support those published by Tuschl and Liu in showing that it is possible to induce the adaptive response in vivo. 1 fig., 4 tabs., 26 refs. (Authors)

Adaptation of instruments developed to study the effectiveness of psychotherapeutic processes

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Shushanikova, Anastasia A.

2016-06-01

Full Text Available The objective of the research was to adapt for use in Russian-language contexts a set of instruments that assess the effectiveness of psychotherapeutic practices. The instruments explore the effectiveness of different types of therapy, without evaluating the abstract, idealized characteristics or specifics of each approach, specialist, or therapeutic case. The adapted instruments are based on reflective data about the significance of therapeutic events, from the point of view of both the client and the therapist. We translated, edited, and adapted forms developed by John McLeod and Mick Cooper — a “Goals Form”, a “Goal Assessment Form”, a “Post-Session Form”, and a “Therapy Personalization Form”. The adaption was intended to cohere with the stylistic and cultural aspects of the Russian language. The research showed that the instruments and the methods have great potential for practical and theoretical application in qualitative studies to formulate hypotheses and to verify them in quantitative studies. The phenomenological analysis reveals the reliability, appropriateness, and validity of the adapted instruments for identifying specific meanings of the psychotherapeutic cases considered. The instruments can be used in studies exploring helpful aspects and effectiveness in different types of therapy (cognitive, existential, outdoor therapy, online counseling, etc. with different groups of clients. It is reasonable to continue the use of the Russian-language version of the instruments in further studies exploring the effectiveness of psychological practices. The adapted instruments facilitate comparison and cross-cultural studies, and formulation of meaningful hypotheses about the effectiveness and quality of the psychotherapeutic process.

When not every response to climate change is a good one: identifying principles for sustainable adaptation

CSIR Research Space (South Africa)

Eriksen, S

2011-01-01

Full Text Available to the need for sustainable adaptation strategies and measures that contribute to social justice and environmental integrity. This paper presents four normative principles to guide responses to climate change and illustrates the significance...

Conflict adaptation in emotional task underlies the amplification of target.

Science.gov (United States)

Chechko, Natalia; Kellermann, Thilo; Schneider, Frank; Habel, Ute

2014-04-01

A primary function of cognitive control is to adjust the cognitive system according to situational demands. The so-called "conflict adaptation effect" elicited in laboratory experiments is supposed to reflect the above function. Neuroimaging studies suggest that adaptation of nonemotional conflict is mediated by the dorsolateral prefrontal cortex through a top-down enhancement of task-relevant (target), relative to task-irrelevant (distractor), stimulus representation in the sensory cortices. The adaptation of emotional conflict, on the other hand, is suggested to be related to the rostral anterior cingulate inhibiting the processing of emotional distractors through a top-down modulation of amygdala responsivity. In the present study, we manipulated, on a trial-by-trial basis, the levels of semantic interference conflict triggered by the incompatibility between emotional faces (targets) and emotional words (distractors) in a modified version of the emotional Stroop task. Similar to previous observations involving nonemotional interference effects, the behavioral adaptation of emotional conflict was found to be paralleled by a stronger recruitment of the fusiform face area. Additional areas related to the conflict adaptation effect were the bilateral insula, the bilateral frontal operculum (fO), the right amygdala, the left precentral and postcentral gyri, and the parietal cortex. These findings suggest that augmentation of cortical responses to task-relevant information in emotional conflict may be related to conflict adaptation processes in a way that has been observed in nonemotional conflict, challenging the view that brain circuitries underlying the conflict adaptation effect depend only on the nature of conflict.

Neurobiological Adaptations to Violence across Development

Science.gov (United States)

Mead, Hilary K.; Beauchaine, Theodore P.; Shannon, Katherine E.

2009-01-01

Adaptation to violent environments across development involves a multitude of cascading effects spanning many levels of analysis from genes to behavior. In this review, we (a) examine the potentiating effects of violence on genetic vulnerabilities and the functioning of neurotransmitter systems in producing both internalizing and externalizing psychopathology, (b) consider the impact of violence on the developing human stress and startle responses, and (c) brain development including the hippocampus and prefrontal cortex. This review integrates literature on the developmental effects of violence on rodents, non-human primates, and humans. Many neurobiological changes that are adaptive for survival in violent contexts become maladaptive in other environments, conferring life-long risk for psychopathology. PMID:20102643

Impact of sub and supra-threshold adaptation currents in networks of spiking neurons.

Science.gov (United States)

Colliaux, David; Yger, Pierre; Kaneko, Kunihiko

2015-12-01

Neuronal adaptation is the intrinsic capacity of the brain to change, by various mechanisms, its dynamical responses as a function of the context. Such a phenomena, widely observed in vivo and in vitro, is known to be crucial in homeostatic regulation of the activity and gain control. The effects of adaptation have already been studied at the single-cell level, resulting from either voltage or calcium gated channels both activated by the spiking activity and modulating the dynamical responses of the neurons. In this study, by disentangling those effects into a linear (sub-threshold) and a non-linear (supra-threshold) part, we focus on the the functional role of those two distinct components of adaptation onto the neuronal activity at various scales, starting from single-cell responses up to recurrent networks dynamics, and under stationary or non-stationary stimulations. The effects of slow currents on collective dynamics, like modulation of population oscillation and reliability of spike patterns, is quantified for various types of adaptation in sparse recurrent networks.

Recent Visual Experience Shapes Visual Processing in Rats through Stimulus-Specific Adaptation and Response Enhancement.

Science.gov (United States)

Vinken, Kasper; Vogels, Rufin; Op de Beeck, Hans

2017-03-20

From an ecological point of view, it is generally suggested that the main goal of vision in rats and mice is navigation and (aerial) predator evasion [1-3]. The latter requires fast and accurate detection of a change in the visual environment. An outstanding question is whether there are mechanisms in the rodent visual system that would support and facilitate visual change detection. An experimental protocol frequently used to investigate change detection in humans is the oddball paradigm, in which a rare, unexpected stimulus is presented in a train of stimulus repetitions [4]. A popular "predictive coding" theory of cortical responses states that neural responses should decrease for expected sensory input and increase for unexpected input [5, 6]. Despite evidence for response suppression and enhancement in noninvasive scalp recordings in humans with this paradigm [7, 8], it has proven challenging to observe both phenomena in invasive action potential recordings in other animals [9-11]. During a visual oddball experiment, we recorded multi-unit spiking activity in rat primary visual cortex (V1) and latero-intermediate area (LI), which is a higher area of the rodent ventral visual stream. In rat V1, there was only evidence for response suppression related to stimulus-specific adaptation, and not for response enhancement. However, higher up in area LI, spiking activity showed clear surprise-based response enhancement in addition to stimulus-specific adaptation. These results show that neural responses along the rat ventral visual stream become increasingly sensitive to changes in the visual environment, suggesting a system specialized in the detection of unexpected events. Copyright © 2017 Elsevier Ltd. All rights reserved.

Renal cortex taurine content regulates renal adaptive response to altered dietary intake of sulfur amino acids.

OpenAIRE

Chesney, R W; Gusowski, N; Dabbagh, S

1985-01-01

Rats fed a reduced sulfur amino acid diet (LTD) or a high-taurine diet (HTD) demonstrate a renal adaptive response. The LTD results in hypotaurinuria and enhanced brush border membrane vesicle (BBMV) accumulation of taurine. The HTD causes hypertaurinuria and reduced BBMV uptake. This adaptation may relate to changes in plasma or renal cortex taurine concentration. Rats were fed a normal-taurine diet (NTD), LTD, or HTD for 14 d or they underwent: (a) 3% beta-alanine for the last 8 d of each d...

Ontogeny of adaptive antibody response to a model antigen in captive altricial zebra finches.

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Tess L Killpack

Full Text Available Based on studies from the poultry literature, all birds are hypothesized to require at least 4 weeks to develop circulating mature B-cell lineages that express functionally different immunoglobulin specificities. However, many altricial passerines fledge at adult size less than four weeks after the start of embryonic development, and therefore may experience a period of susceptibility during the nestling and post-fledging periods. We present the first study, to our knowledge, to detail the age-related changes in adaptive antibody response in an altricial passerine. Using repeated vaccinations with non-infectious keyhole limpet hemocyanin (KLH antigen, we studied the ontogeny of specific adaptive immune response in altricial zebra finches Taeniopygia guttata. Nestling zebra finches were first injected at 7 days (7d, 14 days (14d, or 21 days post-hatch (21d with KLH-adjuvant emulsions, and boosted 7 days later. Adults were vaccinated in the same manner. Induced KLH-specific IgY antibodies were measured using ELISA. Comparisons within age groups revealed no significant increase in KLH-specific antibody levels between vaccination and boost in 7d birds, yet significant increases between vaccination and boost were observed in 14d, 21d, and adult groups. There was no significant difference among age groups in KLH antibody response to priming vaccination, yet KLH antibody response post-boost significantly increased with age among groups. Post-boost antibody response in all nestling age groups was significantly lower than in adults, indicating that mature adult secondary antibody response level was not achieved in zebra finches prior to fledging (21 days post-hatch in zebra finches. Findings from this study contribute fundamental knowledge to the fields of developmental immunology and ecological immunology and strengthen the utility of zebra finches as a model organism for future studies of immune ontogeny.

The innate and adaptive immune response induced by alveolar macrophages exposed to ambient particulate matter

Energy Technology Data Exchange (ETDEWEB)

Miyata, Ryohei; Eeden, Stephan F. van, E-mail: Stephan.vanEeden@hli.ubc.ca

2011-12-15

Emerging epidemiological evidence suggests that exposure to particulate matter (PM) air pollution increases the risk of cardiovascular events but the exact mechanism by which PM has adverse effects is still unclear. Alveolar macrophages (AM) play a major role in clearing and processing inhaled PM. This comprehensive review of research findings on immunological interactions between AM and PM provides potential pathophysiological pathways that interconnect PM exposure with adverse cardiovascular effects. Coarse particles (10 {mu}m or less, PM{sub 10}) induce innate immune responses via endotoxin-toll-like receptor (TLR) 4 pathway while fine (2.5 {mu}m or less, PM{sub 2.5}) and ultrafine particles (0.1 {mu}m or less, UFP) induce via reactive oxygen species generation by transition metals and/or polyaromatic hydrocarbons. The innate immune responses are characterized by activation of transcription factors [nuclear factor (NF)-{kappa}B and activator protein-1] and the downstream proinflammatory cytokine [interleukin (IL)-1{beta}, IL-6, and tumor necrosis factor-{alpha}] production. In addition to the conventional opsonin-dependent phagocytosis by AM, PM can also be endocytosed by an opsonin-independent pathway via scavenger receptors. Activation of scavenger receptors negatively regulates the TLR4-NF-{kappa}B pathway. Internalized particles are subsequently subjected to adaptive immunity involving major histocompatibility complex class II (MHC II) expression, recruitment of costimulatory molecules, and the modulation of the T helper (Th) responses. AM show atypical antigen presenting cell maturation in which phagocytic activity decreases while both MHC II and costimulatory molecules remain unaltered. PM drives AM towards a Th1 profile but secondary responses in a Th1- or Th-2 up-regulated milieu drive the response in favor of a Th2 profile.

Assessment of the Adaptation Strategiesin Rainfed Chickpea in Response to Future Climate Change in Zanjan Province

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Amir Hajarpoor

2016-11-01

Full Text Available Introduction Chickpea (Cicer arietinum L. is cultivated on alarge scale in arid and semiarid environments. Terminal drought and heat stress, among other abiotic and biotic stresses, are the major constraints of yield in most regions of chickpea production. The study of the effects of climate change could help to develop adaptation strategies to promote and stabilize crop yield. This research was aimed to assess adoption strategies in rainfed chickpea in response to Zanjan province’s climate change using a crop simulation model along with providing simulated yield maps using geographical information system (GIS. Materials and methods To study the effects of climate change and simulation the adaptation strategies, the model of Soltani and Sinclair (Soltani & Sinclair, 2011 was used. This model simulates phenological development, leaf development and senescence, mass partitioning, plant nitrogen balance, yield formation and soil water balance. For each location, a baseline period of daily weather data was available (Table 1. Investigated scenarios were historical climate (control and future climate scenarios that included both direct effects of doubling CO2 (350 to 700 ppm and its indirect effects (10% reduced rainfall, 4ºC increase in temperature. The crop model was performed for the different years of baseline period for current and future climate under typical management and cultivar and also under three adaptation strategies in the future climate including Management adaptation (M, Genetic adaptation (G and a combination of both Management and Genetic adaptation (M & G as described below (Table 2: Management – In various studies changing the planting dates as the simplest and least-cost adaptation strategy has been emphasized (Luo et al., 2009; hence a shift in planting dates i.e. sowing 15 days in advance was explored in this study to reduce the risk of the late season drought. Genetics – Changes in genotype have been suggested to be

The science of adaptation. A framework for assessment

International Nuclear Information System (INIS)

Smit, B.; Burton, I.; Street, R.; Klein, R.J.T.; Maciver, D.C.

1999-01-01

This paper outlines what is meant by 'adaptation' to climate change, and how it might be addressed in the IPCC Assessments. Two roles of adaptation in the climate change field are identified: adaptation as part of impact assessment (where the key question is: what adaptations are likely?), and adaptation as part of the policy response (where the central question is: what adaptations are recommended?). The concept of adaptation has been adopted in several fields including climate impact assessment and policy development, risk management, and natural hazards research. A framework for systematically defining adaptations is based on three questions: (1) adaptation to what? (2) who or what adapts? and (3) how does adaptation occur? The paper demonstrates that, for adaptation purposes, climate extremes and variability are integral parts of climate change, along with shifts in mean conditions. Attributes for differentiating adaptations include purposefulness, timing, temporal and spatial scope, effects, form and performance. The framework provides a guide for the treatment of adaptation in the IPCC assessments, both in the assessment of impacts and in the evaluation of adaptive policy options. 64 refs

Not My Problem: Vicarious Conflict Adaptation with Human and Virtual Co-Actors

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Michiel M. Spapé

2016-04-01

Full Text Available The Simon effect refers to an incompatibility between stimulus and response locations resulting in a conflict situation and, consequently, slower responses. Like other conflict effects, it is commonly reduced after repetitions, suggesting an executive control ability, which flexibly rewires cognitive processing and adapts to conflict. Interestingly, conflict is not necessarily individually defined: the Social Simon effect refers to a scenario where two people who share a task show a conflict effect where a single person does not. Recent studies showed these observations might converge into what could be called vicarious conflict adaptation, with evidence indicating that observing someone else’s conflict may subsequently reduce one’s own. While plausible, there is reason for doubt: both the social aspect of the Simon Effect, and the degree to which executive control accounts for the conflict adaptation effect, have become foci of debate in recent studies. Here, we present two experiments that were designed to test the social dimension of the effect by varying the social relationship between the actor and the co-actor. In Experiment 1, participants performed a conflict task with a virtual co-actor, while the actor-observer relationship was manipulated as a function of the similarity between response modalities. In Experiment 2, the same task was performed both with a virtual and with a human co-actor, while heart-rate measurements were taken to measure the impact of observed conflict on autonomous activity. While both experiments replicated the interpersonal conflict adaptation effects, neither showed evidence of the critical social dimension. We consider the findings as demonstrating that vicarious conflict adaptation does not rely on the social relationship between the actor and co-actor.

Contrast adaptation in cat visual cortex is not mediated by GABA.

Science.gov (United States)

DeBruyn, E J; Bonds, A B

1986-09-24

The possible involvement of gamma-aminobutyric acid (GABA) in contrast adaptation in single cells in area 17 of the cat was investigated. Iontophoretic application of N-methyl bicuculline increased cell responses, but had no effect on the magnitude of adaptation. These results suggest that contrast adaptation is the result of inhibition through a parallel pathway, but that GABA does not mediate this process.

All-Coefficient Adaptive Control of Dual-Motor Driving Servo System

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Zhao Haibo

2017-01-01

Full Text Available Backlash nonlinearity and friction nonlinearity exist in dual-motor driving servo system, which reducing system response speed, steady accuracy and anti-interference ability. In order to diminish the adverse effects of backlash and friction nonlinearity to system, we proposed a new all-coefficient adaptive control method. Firstly, we introduced the dynamic model of backlash and friction nonlinearity respectively. Then on this basis, we established the characteristic model when backlash and friction nonlinearity coexist. We used recursive least square method for parameter estimation. Finally we designed the all-coefficient adaptive controller. On the basis of simplex all-coefficient adaptive controller, we designed a feedforward all-coefficient adaptive controller. The simulations of feedforward all-coefficient adaptive control and simplex all-coefficient adaptive control were compared. The results show that the former has quicker response speed, higher steady accuracy, stronger anti-interference performance and better robustness, which validating the efficacy of the proposed control strategy.

[Stress-induced cellular adaptive mutagenesis].

Science.gov (United States)

Zhu, Linjiang; Li, Qi

2014-04-01

The adaptive mutations exist widely in the evolution of cells, such as antibiotic resistance mutations of pathogenic bacteria, adaptive evolution of industrial strains, and cancerization of human somatic cells. However, how these adaptive mutations are generated is still controversial. Based on the mutational analysis models under the nonlethal selection conditions, stress-induced cellular adaptive mutagenesis is proposed as a new evolutionary viewpoint. The hypothetic pathway of stress-induced mutagenesis involves several intracellular physiological responses, including DNA damages caused by accumulation of intracellular toxic chemicals, limitation of DNA MMR (mismatch repair) activity, upregulation of general stress response and activation of SOS response. These responses directly affect the accuracy of DNA replication from a high-fidelity manner to an error-prone one. The state changes of cell physiology significantly increase intracellular mutation rate and recombination activity. In addition, gene transcription under stress condition increases the instability of genome in response to DNA damage, resulting in transcription-associated DNA mutagenesis. In this review, we summarize these two molecular mechanisms of stress-induced mutagenesis and transcription-associated DNA mutagenesis to help better understand the mechanisms of adaptive mutagenesis.

Sleep restriction undermines cardiovascular adaptation during stress, contingent on emotional stability.

Science.gov (United States)

Lü, Wei; Hughes, Brian M; Howard, Siobhán; James, Jack E

2018-02-01

Sleep loss is associated with increased cardiovascular disease, but physiological mechanisms accounting for this relationship are largely unknown. One possible mechanism is that sleep restriction exerts effects on cardiovascular stress responses, and that these effects vary between individuals. Emotional stability (ES) is a personality trait pertinent to sleep restriction and stress responding. However, no study to date has explored how ES and sleep-restriction interactively affect cardiovascular stress responses or processes of adaptation during stress. The present study sought to investigate the association between ES and impact of sleep restriction on cardiovascular function during stress, with particular regard to the trajectory of cardiovascular function change across time. Ninety female university students completed a laboratory vigilance stress task while undergoing continuous cardiovascular (SBP, DBP, HR, SV, CO, TPR) monitoring, after either a night of partial sleep restriction (40% of habitual sleep duration) or a full night's rest. Individuals high in ES showed stable and adaptive cardiovascular (SBP, SV, CO) responses throughout stress exposure, regardless of sleep. In contrast, individuals low in ES exhibited cardiovascular adaptation during stress exposure while rested, but disrupted adaption while sleep-restricted. These findings suggest that sleep-restriction undermines healthful cardiovascular adaptation to stress for individuals low in ES. Copyright © 2017 Elsevier B.V. All rights reserved.

On the effect of response transformations in sequential parameter optimization.