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PubMed2000

Time course of chromatic adaptation for color appearance and discrimination.

Adaptation to a steady background has a profound effect on both color appearance and discrimination. We determined the temporal characteristics of chromatic adaptation for appearance and discrimination along different color directions. Subjects were adapted to a large uniform background made up of a CRT screen and a 45x64 degrees wall, illuminated by computer controlled lamps. After an instant change in background color along a red-green or blue-yellow color axis, we measured thresholds for the detection of increments along the same axes at fixed times between 25 ms and 121 s. Analogously, color appearance was determined using achromatic matching. Three components of adaptation could be identified by their temporal characteristics. A slow exponential time course of adaptation with a half-life of about 20 s was common to appearance and discrimination. A faster component with a half-life of 40-70 ms--probably due to photoreceptor adaptation--was also common to both. Exclusive for color appearance, there was a third, extremely rapid mechanism with a half-life faster than 10 ms. This instantaneous process explained more than 50% of total adaptation for color appearance and could be shown to act in a multiplicative manner. We conclude that this instantaneous adaptation mechanism for color appearance is situated at a later processing stage, after mechanisms common to appearance and discrimination, and is based on multiplicative spatial interactions rather than on local, temporal adaptational processes. Color appearance, and thus color constancy, seems to be determined in large part by cortical computations.

Adaptation, Physiological↗
PubMed2000

A Bayesian system integrating expression data with sequence patterns for localizing proteins: comprehensive application to the yeast genome.

We develop a probabilistic system for predicting the subcellular localization of proteins and estimating the relative population of the various compartments in yeast. Our system employs a Bayesian approach, updating a protein's probability of being in a compartment, based on a diverse range of 30 features. These range from specific motifs (e.g. signal sequences or the HDEL motif) to overall properties of a sequence (e.g. surface composition or isoelectric point) to whole-genome data (e.g. absolute mRNA expression levels or their fluctuations). The strength of our approach is the easy integration of many features, particularly the whole-genome expression data. We construct a training and testing set of approximately 1300 yeast proteins with an experimentally known localization from merging, filtering, and standardizing the annotation in the MIPS, Swiss-Prot and YPD databases, and we achieve 75 % accuracy on individual protein predictions using this dataset. Moreover, we are able to estimate the relative protein population of the various compartments without requiring a definite localization for every protein. This approach, which is based on an analogy to formalism in quantum mechanics, gives better accuracy in determining relative compartment populations than that obtained by simply tallying the localization predictions for individual proteins (on the yeast proteins with known localization, 92% versus 74%). Our training and testing also highlights which of the 30 features are informative and which are redundant (19 being particularly useful). After developing our system, we apply it to the 4700 yeast proteins with currently unknown localization and estimate the relative population of the various compartments in the entire yeast genome. An unbiased prior is essential to this extrapolated estimate; for this, we use the MIPS localization catalogue, and adapt recent results on the localization of yeast proteins obtained by Snyder and colleagues using a minitransposon system. Our final localizations for all approximately 6000 proteins in the yeast genome are available over the web at: http://bioinfo.mbb.yale. edu/genome/localize.

Amino Acid Motifs↗
PubMed1986

Adaptive thermal modeling: a concept for measurement of local blood perfusion in heated tissues.

A new Adaptive Thermal Modeling (ATM) method for the measurement of local tissue blood perfusion rate is introduced. The method is based on a two-phase numerical technique. The first phase includes a fast, finite difference scheme for solution of the transient temperature field. The second phase involves iterative corrections of the perfusion until the modeled temperatures coincide with those measured by the temperature sensors. The results obtained from computer generated "data", as well as from laboratory experiments demonstrate the potential capability of the ATM method to continuously measure local perfusion rates in heated tissues. Rigorous analysis of the technique is planned for the near future so that it can be applied to in vivo measurements of local tissue blood perfusions.

Adaptation, Physiological↗
PubMed1996

Breastfeeding: physiological, endocrine and behavioural adaptations caused by oxytocin and local neurogenic activity in the nipple and mammary gland.

It is now well established that oxytocin, as well as stimulating uterine contractions and milk ejection, promotes the development of maternal behaviour and also bonding between mother and offspring. In addition, oxytocin exerts by way of peripheral, circulating as well as by central, neurogenic mechanisms multiple physiological, endocrine and behavioural effects in connection with milk ejection and lactation. Some effects of oxytocin in the nipple and mammary gland appear to be exerted in close collaboration with peptides released from axon collaterals of somatosensory nerves originating in this region. The distribution of peptides localized to the somatosensory afferents in the nipple and mammary gland as well as possible effects by oxytocin and/or local neurogenic peptides in connection with milk ejection and lactation are reviewed in this paper.

Adaptation, Physiological↗
PubMed2001

Quality of life and psychological adaptation after surgical treatment for localized renal cell carcinoma: impact of the amount of remaining renal tissue.

OBJECTIVES: To analyze the quality of life and psychological adjustment after surgical therapy for localized renal cell carcinoma. METHODS: Postal questionnaires including measures of quality of life (SF-36) and the impact of the stress of cancer (Impact of Events Scale) were completed by 97 patients who had undergone radical or partial nephrectomy for localized renal cell carcinoma. Data were analyzed for the group as a whole and comparing the partial nephrectomy and radical nephrectomy groups. The variables examined included the impact of the type of partial nephrectomy (elective versus mandatory) and the amount of self-reported renal tissue remaining. RESULTS: The quality of life for the group as a whole was good, with no significant differences between the sample and U.S. norms for an age and sex-matched community sample on both the mental and physical health composite scores. Having undergone a partial versus a radical nephrectomy did not influence the patients' overall quality of life. Multiple linear regression modeling demonstrated that having more remaining renal parenchyma was an independent predictor of better self-reported physical health on the SF-36 (P <0.001). The entire sample had low mean scores on both avoidance and intrusion on the Impact of Events Scale, suggesting a lack of daily anxiety about cancer. Multiple linear regression modeling showed that patients who reported having more remaining renal parenchyma had lower intrusion and avoidance scores (P = 0.002 and 0.01, respectively). Multiple logistic regression modeling also demonstrated that the patients' perception of their remaining renal parenchyma was associated with less concern about cancer recurrence (P = 0.018) and less impact of cancer on patients' overall health (P <0.001). CONCLUSIONS: Most survivors of localized kidney cancer have normal physical and mental health regardless of the type of nephrectomy performed. The quality of life is better for patients with more renal parenchyma remaining after surgery for localized renal cell carcinoma.

Adaptation, Psychological↗
PubMed1990

[Eye surgery in Sudan].

A seven-week stay in the Sudan in the winter of 1988/89 revealed the ophthalmological problems of this Third World country. As a result of the catastrophic shortage of local doctors, many cases of eye disease have progressed to terminal stages. Of 990 patients examined, 80% were unilaterally or bilaterally blind. The three main causes of blindness were cataract, trachoma, and glaucoma. The most effective treatment for these conditions was surgery. Operable cases were identified by a simple examination method, and a total of 330 operations were performed, of which 63% were for cataract and 21% for trichiasis. Trabeculectomy was performed in 9% of the cases in order to prevent absolute glaucoma. Owing to the many technical, personnel, and specific local problems complicated surgical methods were inappropriate. As in war surgery, the methods applied had to be simple and fast. In order to achieve any success it was necessary to abandon perfectionist western methods and adapt to locally available facilities. In the author's view, a well-prepared assignment of this kind can be a useful experience for any ophthalmologist.

Developing Countries↗
PubMed1979

Adaptation effects on the apparent "squareness" of square-wave gratings.

Adaptation to a 9 cycles deg-1 sine wave makes the apparent brightness profile of a 3 cycles deg-1 square wave look less "square" even when it does not look like that of a sine wave. Adaptation to a 3 cycles deg-1 sine wave has no noticeable effect. Hypotheses based on "excitation patterns" across spatial-frequency-selective channels can account for these results; it is not clear whether variations in local light adaptation can also account for them.

Adaptation, Ocular↗
PubMed2006

[Genetic and correlation analysis for agronomic traits in flue-cured tobacco (Nicotiana tabacum L.)].

By using a genetic model including additive and dominance effects and their interaction with environments, 7 agronomic traits were analyzed for a diallel design in 4 environmental conditions with 14 flue-cured tobacco varieties (or breeding lines) and their 41 F1 crosses. It was revealed that additive effects were the major genetic component for plant height, internode length, and width of leaves. Number of leaves and length of leaves were mainly controlled by dominance x environment interaction effects. Additive x environment interaction effects and dominance x environment interaction effects played a major role for girth of stem. Yield performance was mainly controlled by additive effects and dominance x environment interaction effects. The varieties adapted to local environments tended to have highly positive additive effects. Dominance effects and the dominance x environment interaction effects could perform differently in positive or negative direction for many crosses. The breeding program for hybrids should consider the adaptation of hybrids to specific ecological environments. The analysis of correlation among agronomic traits indicated that most of phenotypic, genotypic, additive and dominance correlation coefficients were positive. Additive correlations were predominance in genetic correlations for most pairs of traits. Yield can be improved by indirect selection on plant height.

Genotype↗
PubMed2004

Adaptation to spiral motion: global but not local motion detectors are modulated by attention.

In this study, we investigated the effect of attention on local motion detectors. For this purpose we used logarithmic spirals previously used by Cavanagh and Favreau [Perception, 1980, 9(2), 175-182]. While the adapting stimulus was a rotating logarithmic spiral, the test stimulus was either the same spiral or its mirror image. When superimposed, all contours of the spiral stimulus and its mirror image are 90 degrees apart. Presenting the same spiral during the test period shows adaptation of both local motion detectors and global rotation detectors, whereas showing the mirror-spiral stimulates another set of local motion detectors, and therefore illustrates adaptation at only the global motion level. To manipulate the attentional state of observers, a secondary task was presented during the adaptation phase and observers either performed the task or ignored it. Motion aftereffect (MAE) duration was measured afterwards. While the effects of attention and test stimulus type on MAE duration were both significant, the difference in the MAE strength between the attention-distracted and attention-not-distracted conditions was equal when the test stimulus was the same-spiral or the mirror-spiral, suggesting that attention to spiral motion modulates only global rotation units and does not affect local motion detectors located at V1. Our results are in accord with those reported by Watanabe et al. [Proceedings of the National Academy of Sciences of the USA, 1998, 95(19), 11489-11492] which showed differential modulation of motion processing areas depending on the type of motion being attended. Therefore our data are supportive of the notion that attentional modulation of V1 is highly task-dependent.

Adaptation, Ocular↗
PubMed1976

Compensatory adaptation of sodium and bicarbonate excretion: effect of diuretics.

Complete clamping of the contralateral kidney results in a rapid and significant increase in the fractional excretion of Na, K, and bicarbonate by the remaining kidney during bicarbonate loading. Similar studies were performed in dogs after administration of diuretics with different major sites of action to localize the adaptive excretory response to acute reduction in renal mass. Volume expansion was carefully avoided. In experiments with the loop inhibitor, furosemide, contralateral kidney clamping rapidly and significantly increased fractional excretion of Na and bicarbonate. A more delayed and smaller response was observed in dogs given hydrochlorothiazide. Acetazolamide, a potent inhibitor of proximal Na bicarbonate reabsorption, completely blocked the excretory response to contralateral kidney clamping. The enhanced response with furosemide and its blockade with acetazolamide indicates a proximal site of adaptation to acute contralateral kidney exclusion. The overall natriuretic response depends on the level of inhibition of loop reabsorption.

Acetazolamide↗
PubMed2006

What makes for sustainable Healthy Cities initiatives?--A review of the evidence from Noarlunga, Australia after 18 years.

This paper examines the factors that have enabled the Healthy Cities Noarlunga (HCN) initiative to be sustainable over 18 years (1987-2005). Sustainability related to the ability of the initiative to continue to operate continuously in a manner that indicated its existence was accorded value by the community and local service providers. The analysis is based on a narrative review of 29 documents related to HCN, including a number of evaluations. Nine factors emerged as important to ensuring sustainability: strong social health vision; inspirational leadership; a model that can adapt to local conditions; ability to juggle competing demands; strongly supported community involvement that represents genuine engagement; recognition by a broad range of players that Healthy Cities is a relatively neutral space in which to achieve goals; effective and sustainable links with a local university; an outward focus open to international links and outside perspectives; and, most crucial, the initiative makes the transition from a project to an approach and a way of working. These sustainability factors are likely to be relevant to a range of complex, community-based initiatives.

Community Health Planning↗
PubMed2000

Improving egg production in two indigenous communities through the adaptation of management practices and local knowledge. The results of participative research.

Free-ranging poultry (FRP) are known to be efficient in the recycling of residues of agroforestry systems. The objective of this paper is to present the results of participative applied research on the improvement of egg production in two indigenous communities in Costa Rica. This involved a dialectic process of adaptation between indigenous knowledge and introduced management practices. We report an increase in egg production through the use of nests and improved diets.

Animal Feed↗
PubMed2006

Management of APL in developing countries: epidemiology, challenges and opportunities for international collaboration.

Acute promyelocytic leukemia (APL), a relatively rare hematologic malignancy, is highly curable with current treatment strategies. However, these strategies may be unavailable in countries with limited resources. A review of records in several Latin American countries revealed that approximately 30% of deaths among children and adults with APL were caused by early complications associated with the disease or its treatment. Further, APL accounts for 20% to 25% of cases of AML in these countries, consistent with the previous observation of increased incidence of APL in Latin Americans. The lack of population-based registries in developing countries has made it difficult to determine the real incidence of APL. Moreover, APL appears to have other unique epidemiologic characteristics, including association of primary APL with an increased body mass index at diagnosis and association of secondary APL with breast cancer. To facilitate the development of local capacity and implement effective treatment of APL in developing countries, the International Committee of the American Society of Hematology has assembled a working group to formulate treatment guidelines based on evidence from clinical trials results in the developed world but adapted to local resources. It is hoped that uniform treatment, careful documentation of specific outcome data, and ongoing monitoring of treatment efficacy and toxicity will improve the cure rate and provide biologic and epidemiologic information about APL in developing countries. This initial demonstration project may be joined by other countries, providing a framework for additional clinical investigation in this highly curable form of leukemia.

Developing Countries↗
PubMed1982

[Desynchronization and resynchronization after west-east and east-west transmeridian flight].

Changes of some parameters of circadian rhythms (mesor, amplitude, acrophase) have been studied in healthy students and physicians during a double transmeridian flight : westward (Rome-Jakarta-Ambon Maluku Islands) and eastward direction (Ambon, Rome). In the present study, performed in November-December, both an acute effect of transmeridian flight on different variables particularly the rate of adaptation to local time, and a long-term effect have been studied. The following variables have been measured : 1) oral temperature (T.); 2) systolic blood pressure (S.B.P.); 3) diastolic blood pressure (D.B.P.) by automatic apparatus; 4) a memory test (M.) (a fixed number of playing cards in a fixed time); 5) eye-hand skull (E.H.S.) - the time necessary to order a fixed number of playing cards according to colour and suit; 6) fusion critical frequency (F.C.F.) of retinal vision. Measurements were performed at 4-hour intervals by autorythmometry. In conclusion it is possible to point out in this experience an asymmetry-effect in the adaptation of circadian rhythms according to the direction of flight : in the westward flight the acrophases of T, SBP and EHS approach, within 72 hrs, those previously observed before the beginning of the study, whereas in Jakarta, 24 hrs after the eastward flight the same variables maintain the same acrophases of Rome local time, within the first 24 hrs, and completely adjust to local time within ten day in Ambon.

Adaptation, Physiological↗
PubMed2005

Phylogenetic and environmental components of morphological variation: skull, mandible, and molar shape in marmots (Marmota, Rodentia).

The phenotype is a product of its phylogenetic history and its recent adaptation to local environments, but the relative importance of the two factors is controversial. We assessed the effects of diet, habitat, elevation, temperature, precipitation, body size, and mtDNA genetic divergence on shape variation in skulls, mandibles, and molars, structures that differ in their genetic and functional control. We asked whether these structures have adapted to environment to the same extent and whether they retain the same amount of phylogenetic signal. We studied these traits in intra- and interspecific populations of Eurasian marmots whose last common ancestor lived 2-5 million years ago. Path Analysis revealed that body size explained 10% of variation in skulls, 7% in mandibles, and 15% in molars. Local vegetation explained 7% of variation in skulls, 11% in mandibles, and 12% in molars. Dietary category explained 25% of variation in skulls, 11% in mandibles, and 9% in molars. Cyt b mtDNA divergence (phylogeny) explained 15% of variation in skulls, 7% in mandibles, and 5% in molars. Despite the percentages of phylogenetic variance, maximum-likelihood trees based on molar and skull shape recovered most phylogenetic groupings correctly, but mandible shape did not. The good performance of molars and skulls was probably due to different factors. Skulls are genetically and functionally more complicated than teeth, and they had more mathematically independent components of variation (5-6-in skulls compared to 3-in molars). The high proportion of diet-related variance was not enough to mask the phylogenetic signal. Molars had fewer independent components, but they also have less ecophenotypic variation and evolve more slowly, giving each component a proportionally stronger phylogenetic signal. Molars require larger samples for each operational taxonomic unit than the other structures because the proportion of within-taxon to between-taxon variation was higher. Good phylogenetic signal in quantitative skeletal morphology is likely to be found only when the taxa have a common ancestry no older than hundreds of thousands or millions of years (1% to 10% mtDNA divergence)--under these conditions skulls and molars provide stronger signal than mandibles.

Animals↗
PubMed2000

The interaction between research and practice: a pan-European approach to managing H.pylori infection in primary care.

The transposition of evidence into clinical care presents many challenges. New knowledge may be immediately translatable to the practice setting, with barriers to be overcome before implementation. The early guidelines on Helicobacter pylori management presented an overview but were not able to take into account local factors and health care traditions, such as the non-availability of tests and established primary-secondary care relationships. Primary care is a specific specialty across most of Europe, existing within different health care systems and clinical traditions. The creation of H. pylori management guidelines, aimed at European primary care but adaptable to local national circumstances, presented a challenge in methodology and formulation. The process exposed similarities but also tensions between differing health care systems, as well as variations in the conditions in which GPs practise. Clinical differences, such as varying ulcer prevalence and drug resistance rates, highlighted the importance of guidelines being adaptable. This paper analyses the European Society for Primary Care Gastroenterology process of pan-European primary care agreement towards H.pylori management and how diverse views, traditions and national settings were reconciled through an evidence-based approach.

Cultural Diversity↗
PubMed2002

Hitchhiking mapping: a population-based fine-mapping strategy for adaptive mutations in Drosophilamelanogaster.

The identification of genes contributing to the adaptation of local populations is of great biological interest. In an attempt to characterize functionally important differences among African and non-African Drosophila melanogaster populations, we surveyed neutral microsatellite variation in an 850-kb genomic sequence. Three genomic regions were identified that putatively bear an adaptive mutation associated with the habitat expansion of D. melanogaster. A further inspection of two regions by sequence analysis of multiple fragments confirmed the presence of a recent beneficial mutation in the non-African populations. Our study suggests that hitchhiking mapping is a universal approach for the identification of ecologically important mutations.

Alleles↗
PubMed2003

The role of stomata in sensing and driving environmental change.

Stomata, the small pores on the surfaces of leaves and stalks, regulate the flow of gases in and out of leaves and thus plants as a whole. They adapt to local and global changes on all timescales from minutes to millennia. Recent data from diverse fields are establishing their central importance to plant physiology, evolution and global ecology. Stomatal morphology, distribution and behaviour respond to a spectrum of signals, from intracellular signalling to global climatic change. Such concerted adaptation results from a web of control systems, reminiscent of a 'scale-free' network, whose untangling requires integrated approaches beyond those currently used.

Acclimatization↗