Visual noise disrupts conceptual integration in reading.

PubMed

Gao, Xuefei; Stine-Morrow, Elizabeth A L; Noh, Soo Rim; Eskew, Rhea T

2011-02-01

The Effortfulness Hypothesis suggests that sensory impairment (either simulated or age-related) may decrease capacity for semantic integration in language comprehension. We directly tested this hypothesis by measuring resource allocation to different levels of processing during reading (i.e., word vs. semantic analysis). College students read three sets of passages word-by-word, one at each of three levels of dynamic visual noise. There was a reliable interaction between processing level and noise, such that visual noise increased resources allocated to word-level processing, at the cost of attention paid to semantic analysis. Recall of the most important ideas also decreased with increasing visual noise. Results suggest that sensory challenge can impair higher-level cognitive functions in learning from text, supporting the Effortfulness Hypothesis.

Trade-offs between reproductive allocation and storage in species of Oenothera L. (Onagraceae) native to Argentina

NASA Astrophysics Data System (ADS)

Vilela, Alejandra; Cariaga, Rodrigo; González-Paleo, Luciana; Ravetta, Damián

2008-01-01

A trade-off between reproduction and survival arises because current reproduction diminishes levels of a limiting resource such that less can be placed in storage organs for the survival of an organism during the unfavorable season. Oenothera is a particularly suited genus for studying those kind of trade-offs because it contains species with different life-history strategies (annual, biennial and perennial). Since allocation to leaves is a major factor associated with changes in life-history, here we tested the hypothesis that Oenothera leaf attributes would affect plant reproductive effort and therefore, root reserves. We selected two groups of taxa differing in their leaf area ratio (low- and high-LAR) and we compared their pattern of resource allocation to growth, reproduction and storage. Path analysis confirmed our hypothesis that LAR is the most important variable in explaining variation in allocation to reproduction or storage. The group with high allocation to leaves assigned resources preferentially to storage while the other group allocated more resources to reproduction, as predicted. A trade-off between reproduction and storage was only confirmed for the high-LAR group. The low-LAR group showed the life-history tactic of annual plants, while the high-LAR group exhibited a strategy generally associated with perenniality.

Sex Differences, Sex-Role Orientation, and Reward Allocations.

ERIC Educational Resources Information Center

Olejnik, Anthony B.

1982-01-01

In separate studies, examined (1) ways that college students allocated rewards to children performing in team and competitive situations, and (2) the relationship between sex role orientation and reward allocations. Found that sex and situational differences in reward allocations are affected by sex role orientation and differential socialization…

Biomass allocation and nutrients balance related to the concentration of Nitrogen and Phosphorus in Salvinia auriculata (Salviniaceae).

PubMed

Medeiros, J C C; Coelho, F F; Teixeira, E

2016-06-01

Aquatic plants can use differential allocation (trade-off) of carbon among their structures depending on the nutrition concentration. Given that N and P are limiting in the growth of plants, our questions were: Are the N and P concentrations in S. auriculata related to the biomass allocation to its structures? Is a differential allocation of N and P between floating and submerged leaves? We evaluated the relation between the nutrients and the biomass allocation, and the trade-off among the leaves using the Spearman correlation. Our results showed that N and P concentrations in S. auriculata are related to the biomass allocation to its structures, and that there is no trade-off of these nutrients between "shoot and root". Thus, we can see the importance of N and P concentration in the biomass of S. auriculata, and why this plant is capable to development in different environments as a weedy.

Modulation of Automatic Semantic Priming by Feature-Specific Attention Allocation

ERIC Educational Resources Information Center

Spruyt, Adriaan; De Houwer, Jan; Hermans, Dirk

2009-01-01

We argue that the semantic analysis of task-irrelevant stimuli is modulated by feature-specific attention allocation. In line with this hypothesis, we found semantic priming of pronunciation responses to depend upon the extent to which participants focused their attention upon specific semantic stimulus dimensions. In Experiment 1, we examined the…

Herbivore-induced shifts in carbon and nitrogen allocation in red oak seedlings

Treesearch

Christopher J. Frost; Mark D. Hunter

2008-01-01

A dual-isotope, microcosm experiment was conducted with Quercus rubra (red oak) seedlings to test the hypothesis that foliar herbivory would increase belowground carbon allocation (BCA), carbon (C) rhizodeposition and nitrogen (N) uptake. Plant BCA links soil ecosystems to aboveground processes and can be affected by insect herbivores, though the...

Eyes wide open: enhanced pupil dilation when selectively studying important information.

PubMed

Ariel, Robert; Castel, Alan D

2014-01-01

Remembering important information is imperative for efficient memory performance, but it is unclear how we encode important information. The current experiment evaluated two non-exclusive hypotheses for how learners selectively encode important information at the expense of less important information (differential resource allocation and information reduction). To evaluate these hypotheses, we measured changes in learners' pupil diameter and fixation durations while participants performed a selectivity task that involved studying lists consisting of words associated with different point values. Participants were instructed to maximize their score on a free recall task that they completed after studying each list. Participants' pupils dilated more when studying high-valued than low-valued words, and these changes were associated with better memory for high-valued words. However, participants fixated equally on words regardless of their value, which is inconsistent with the information reduction hypothesis. Participants also increased their memory selectivity across lists, but changes in pupil diameter and differences in fixations could not account for this increased selectivity. The results suggest that learners allocate attention differently to items as a function of their value, and that multiple processes and operations contribute to value-directed remembering.

Eyes Wide Open: Enhanced Pupil Dilation When Selectively Studying Important Information

PubMed Central

Ariel, Robert; Castel, Alan D.

2013-01-01

Remembering important information is imperative for efficient memory performance, but it is unclear how we encode important information. The current experiment evaluated two non-exclusive hypotheses for how learners selectively encode important information at the expense of less important information (differential resource allocation and information reduction). To evaluate these hypotheses, we measured changes in learners’ pupil diameter and fixation durations while participants performed a selectivity task that involved studying lists consisting of words associated with different point values. Participants were instructed to maximize their score on a free recall task that they completed after studying each list. Participants’ pupils dilated more when studying high-valued than low-valued words, and these changes were associated with better memory for high-valued words. However, participants fixated equally on words regardless of their value, which is inconsistent with the information reduction hypothesis. Participants also increased their memory selectivity across lists, but changes in pupil diameter and differences in fixations could not account for this increased selectivity. The results suggest that learners allocate attention differently to items as a function of their value, and that multiple processes and operations contribute to value-directed remembering. PMID:24162863

The Effects of Prior Knowledge Activation on Free Recall and Study Time Allocation.

ERIC Educational Resources Information Center

Machiels-Bongaerts, Maureen; And Others

The effects of mobilizing prior knowledge on information processing were studied. Two hypotheses, the cognitive set-point hypothesis and the selective attention hypothesis, try to account for the facilitation effects of prior knowledge activation. These hypotheses predict different recall patterns as a result of mobilizing prior knowledge. In…

The Role of Status in Producing Depressed Entitlement in Women's and Men's Pay Allocations

ERIC Educational Resources Information Center

Hogue, Mary; Yoder, Janice D.

2003-01-01

Extensive empirical evidence confirms a depressed entitlement effect wherein women pay themselves less than men for comparable work and believe the allocation fair. The present study tests the hypothesis that status subordination linked to being female underlies at least some of this effect. A 2 x 3 design crossed 180 undergraduates' gender with a…

Molecular and morphological differentiation between two Miocene-divergent lineages of Amazonian shrimps, with the description of a new species (Decapoda, Palaemonidae, Palaemon)

PubMed Central

Carvalho, Fabrício Lopes; Magalhães, Célio; Mantelatto, Fernando Luis

2014-01-01

Abstract Palaemon carteri (Gordon, 1935) and Palaemon ivonicus (Holthuis, 1950) are morphologically similar species of South American freshwater shrimps. Past studies have questioned the taxonomic status of both species, which are supposed to have partially sympatric geographic distributions in the Amazon basin. We analyzed a 550 bp fragment of the mitochondrial 16S rRNA gene from these Amazonian Palaemon species as well as from 11 palaemonids as the outgroup. Additionally, we checked diagnostic characters of the genus and family as well as other morphological characters that have been little explored before. Palaemon carteri and Palaemon ivonicus are allocated in two sister lineages, with wide genetic divergence and little morphological differentiation. The divergence time between these lineages was estimated as approximately 10 million years ago. Both molecular and morphological data support the taxonomic validity of both Palaemon carteri and Palaemon ivonicus, refuting the hypothesis of synonymy. In addition, a new species, Palaemon yuna sp. n., closely related to Palaemon ivonicus, is described. Our findings indicate that these species can be differentiated using the projection of the anterolateral margin and anterolateral spine of the first antennular segment, shape of the rostrum, and relative size of the appendix masculina. PMID:25561832

Vocabulary Acquisition through Cloze Exercises, Sentence-Writing and Composition-Writing: Extending the Evaluation Component of the Involvement Load Hypothesis

ERIC Educational Resources Information Center

Zou, Di

2017-01-01

This research inspects the allocation of involvement load to the evaluation component of the involvement load hypothesis, examining how three typical approaches to evaluation (cloze-exercises, sentence-writing, and composition-writing) promote word learning. The results of this research were partially consistent with the predictions of the…

Modeling Differentiation of Cognitive Abilities within the Higher-Order Factor Model Using Moderated Factor Analysis

ERIC Educational Resources Information Center

Molenaar, Dylan; Dolan, Conor V.; Wicherts, Jelte M.; van der Maas, Han L. J.

2010-01-01

The general differentiation hypothesis states that the strength of the correlations among a set of IQ subtests varies with a given variable. Instances of the general differentiation hypothesis that have been considered in the literature include age and ability differentiation. Traditionally, the differentiation effect is attributed to the varying…

Watching sexy displays improves hatching success and offspring growth through maternal allocation.

PubMed

Loyau, Adeline; Lacroix, Frédéric

2010-11-22

Male attractiveness can have tremendous effects on the fitness of his offspring via good genes, but also via enhanced maternal allocation of resources. Yet the proximate mechanisms influencing differential maternal allocation in relation to male sexiness are poorly known. Here, we studied the importance of visual stimulation for maternal allocation in the Houbara bustard, a vulnerable bird species bred in captivity to support wild populations. Artificial insemination allowed controlling for potential confounding factors, such as a male's territory quality, social interactions or sperm quality/quantity, probably linked to mate attractiveness. We show that artificially inseminated females stimulated by highly displaying males increased their hatching success, owing to increased fertilization success. The females also increased the allocation of maternal androgens in their eggs, leading to an increase of circulating testosterone and growth rate in chicks. Hence, visual stimulation of the females can promote differential maternal allocation and favour offspring fitness. Our results further suggest that using artificial insemination for species conservation without appropriate stimulation of the breeding females probably has negative impacts on their breeding performance and therefore on population viability.

Longitudinal Dimensionality of Adolescent Psychopathology: Testing the Differentiation Hypothesis

ERIC Educational Resources Information Center

Sterba, Sonya K.; Copeland, William; Egger, Helen L.; Costello, E. Jane; Erkanli, Alaattin; Angold, Adrian

2010-01-01

Background: The differentiation hypothesis posits that the underlying liability distribution for psychopathology is of low dimensionality in young children, inflating diagnostic comorbidity rates, but increases in dimensionality with age as latent syndromes become less correlated. This hypothesis has not been adequately tested with longitudinal…

Pushed aside: Parentheticals, Memory and Processing

PubMed Central

Dillon, Brian; Clifton, Charles; Frazier, Lyn

2014-01-01

In the current work, we test the hypothesis that ‘at-issue’ and 'not-at-issue' content (Potts, 2005) are processed semi-independently. In a written rating study comparing restrictive relative clauses and parentheticals in interrogatives and declaratives, we observe a significantly larger length penalty for restrictive relative clauses than for parentheticals. This difference cannot be attributed to differences in how listeners allocate attention across a sentence: a second study confirms that readers are equally sensitive to agreement violations in at-issue and not-at-issue content. A third rating experiment showed that the results do not depend on the restrictive relative clause intervening on the subject-verb dependency. A final experiment showed that the observed effects obtain with definite determiners and demonstratives alike. Taken jointly the results suggest that the parenthetical structures are processed independently of their embedding utterance, which in turn suggests that syntactic memory may be more differentiated than is typically assumed. PMID:24812639

Perceived state of self during motion can differentially modulate numerical magnitude allocation.

PubMed

Arshad, Q; Nigmatullina, Y; Roberts, R E; Goga, U; Pikovsky, M; Khan, S; Lobo, R; Flury, A-S; Pettorossi, V E; Cohen-Kadosh, R; Malhotra, P A; Bronstein, A M

2016-09-01

Although a direct relationship between numerical allocation and spatial attention has been proposed, recent research suggests that these processes are not directly coupled. In keeping with this, spatial attention shifts induced either via visual or vestibular motion can modulate numerical allocation in some circumstances but not in others. In addition to shifting spatial attention, visual or vestibular motion paradigms also (i) elicit compensatory eye movements which themselves can influence numerical processing and (ii) alter the perceptual state of 'self', inducing changes in bodily self-consciousness impacting upon cognitive mechanisms. Thus, the precise mechanism by which motion modulates numerical allocation remains unknown. We sought to investigate the influence that different perceptual experiences of motion have upon numerical magnitude allocation while controlling for both eye movements and task-related effects. We first used optokinetic visual motion stimulation (OKS) to elicit the perceptual experience of either 'visual world' or 'self'-motion during which eye movements were identical. In a second experiment, we used a vestibular protocol examining the effects of perceived and subliminal angular rotations in darkness, which also provoked identical eye movements. We observed that during the perceptual experience of 'visual world' motion, rightward OKS-biased judgments towards smaller numbers, whereas leftward OKS-biased judgments towards larger numbers. During the perceptual experience of 'self-motion', judgments were biased towards larger numbers irrespective of the OKS direction. Contrastingly, vestibular motion perception was found not to modulate numerical magnitude allocation, nor was there any differential modulation when comparing 'perceived' vs. 'subliminal' rotations. We provide a novel demonstration that numerical magnitude allocation can be differentially modulated by the perceptual state of self during visual but not vestibular mediated motion. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Biomass partitioning and its relationship with the environmental factors at the alpine steppe in Northern Tibet.

PubMed

Wu, Jianbo; Hong, Jiangtao; Wang, Xiaodan; Sun, Jian; Lu, Xuyang; Fan, Jihui; Cai, Yanjiang

2013-01-01

Alpine steppe is considered to be the largest grassland type on the Tibetan Plateau. This grassland contributes to the global carbon cycle and is sensitive to climate changes. The allocation of biomass in an ecosystem affects plant growth and the overall functioning of the ecosystem. However, the mechanism by which plant biomass is allocated on the alpine steppe remains unclear. In this study, biomass allocation and its relationship to environmental factors on the alpine grassland were studied by a meta-analysis of 32 field sites across the alpine steppe of the northern Tibetan Plateau. We found that there is less above-ground biomass (M A ) and below-ground biomass (M B ) in the alpine steppe than there is in alpine meadows and temperate grasslands. By contrast, the root-to-shoot ratio (R:S) in the alpine steppe is higher than it is in alpine meadows and temperate grasslands. Although temperature maintained the biomass in the alpine steppe, precipitation was found to considerably influence M A , M B , and R:S, as shown by ordination space partitioning. After standardized major axis (SMA) analysis, we found that allocation of biomass on the alpine steppe is supported by the allometric biomass partitioning hypothesis rather than the isometric allocation hypothesis. Based on these results, we believe that M A and M B will decrease as a result of the increased aridity expected to occur in the future, which will reduce the landscape's capacity for carbon storage.

Do Black Students Misbehave More? Investigating the Differential Involvement Hypothesis and Out-of-School Suspensions

ERIC Educational Resources Information Center

Huang, Francis L.

2018-01-01

Black students are much more likely to be disciplined using out-of-school suspensions (OSS) compared with White students. One often-cited hypothesis, though relatively untested, is the role of misconduct and students attitudes that support deviant behavior. The differential involvement hypothesis suggests that disproportionate sanctioning may…

Plants adapted to nutrient limitation allocate less biomass into stems in an arid-hot grassland.

PubMed

Yan, Bangguo; Ji, Zhonghua; Fan, Bo; Wang, Xuemei; He, Guangxiong; Shi, Liangtao; Liu, Gangcai

2016-09-01

Biomass allocation can exert a great influence on plant resource acquisition and nutrient use. However, the role of biomass allocation strategies in shaping plant community composition under nutrient limitations remains poorly addressed. We hypothesized that species-specific allocation strategies can affect plant adaptation to nutrient limitations, resulting in species turnover and changes in community-level biomass allocations across nutrient gradients. In this study, we measured species abundance and the concentrations of nitrogen and phosphorus in leaves and soil nutrients in an arid-hot grassland. We quantified species-specific allocation parameters for stems vs leaves based on allometric scaling relationships. Species-specific stem vs leaf allocation parameters were weighted with species abundances to calculate the community-weighted means driven by species turnover. We found that the community-weighted means of biomass allocation parameters were significantly related to the soil nutrient gradient as well as to leaf stoichiometry, indicating that species-specific allocation strategies can affect plant adaptation to nutrient limitations in the studied grassland. Species that allocate less to stems than leaves tend to dominate nutrient-limited environments. The results support the hypothesis that species-specific allocations affect plant adaptation to nutrient limitations. The allocation trade-off between stems and leaves has the potential to greatly affect plant distribution across nutrient gradients. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

A novel dynamic wavelength bandwidth allocation scheme over OFDMA PONs

NASA Astrophysics Data System (ADS)

Yan, Bo; Guo, Wei; Jin, Yaohui; Hu, Weisheng

2011-12-01

With rapid growth of Internet applications, supporting differentiated service and enlarging system capacity have been new tasks for next generation access system. In recent years, research in OFDMA Passive Optical Networks (PON) has experienced extraordinary development as for its large capacity and flexibility in scheduling. Although much work has been done to solve hardware layer obstacles for OFDMA PON, scheduling algorithm on OFDMA PON system is still under primary discussion. In order to support QoS service on OFDMA PON system, a novel dynamic wavelength bandwidth allocation (DWBA) algorithm is proposed in this paper. Per-stream QoS service is supported in this algorithm. Through simulation, we proved our bandwidth allocation algorithm performs better in bandwidth utilization and differentiate service support.

Time allocation of disabled individuals.

PubMed

Pagán, Ricardo

2013-05-01

Although some studies have analysed the disability phenomenon and its effect on, for example, labour force participation, wages, job satisfaction, or the use of disability pension, the empirical evidence on how disability steals time (e.g. hours of work) from individuals is very scarce. This article examines how disabled individuals allocate their time to daily activities as compared to their non-disabled counterparts. Using time diary information from the Spanish Time Use Survey (last quarter of 2002 and the first three quarters of 2003), we estimate the determinants of time (minutes per day) spent on four aggregate categories (market work, household production, tertiary activities and leisure) for a sample of 27,687 non-disabled and 5250 disabled individuals and decompose the observed time differential by using the Oaxaca-Blinder methodology. The results show that disabled individuals devote less time to market work (especially females), and more time to household production (e.g. cooking, cleaning, child care), tertiary activities (e.g., sleeping, personal care, medical treatment) and leisure activities. We also find a significant effect of age on the time spent on daily activities and important differences by gender and disability status. The results are consistent with the hypothesis that disability steals time, and reiterate the fact that more public policies are needed to balance working life and health concerns among disabled individuals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Competing Principles for Allocating Health Care Resources.

PubMed

Carter, Drew; Gordon, Jason; Watt, Amber M

2016-10-01

We clarify options for conceptualizing equity, or what we refer to as justice, in resource allocation. We do this by systematically differentiating, expounding, and then illustrating eight different substantive principles of justice. In doing this, we compare different meanings that can be attributed to "need" and "the capacity to benefit" (CTB). Our comparison is sharpened by two analytical tools. First, quantification helps to clarify the divergent consequences of allocations commended by competing principles. Second, a diagrammatic approach developed by economists Culyer and Wagstaff offers a visual and conceptual aid. Of the eight principles we illustrate, only two treat as relevant both a person's initial health state and a person's CTB per resource unit expended: (1) allocate resources so as to most closely equalize final health states and (2) allocate resources so as to equally restore health states to population norms. These allocative principles ought to be preferred to the alternatives if one deems relevant both a person's initial health state and a person's CTB per resource unit expended. Finally, we examine some possibilities for conceptualizing benefits as relative to how badly off someone is, extending Parfit's thought on Prioritarianism (a prioritizing of the worst off). Questions arise as to how much intervention effects accruing to the worse off count for more and how this changes with improving health. We explicate some recent efforts to answer these questions, including in Dutch and British government circles. These efforts can be viewed as efforts to operationalize need as an allocative principle. Each effort seeks to maximize in the aggregate quanta of effect that are differentially valued in favor of the worst off. In this respect, each effort constitutes one type of Prioritarianism, which Parfit failed to differentiate from other types. © The Author 2016. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Bayesian adaptive phase II screening design for combination trials.

PubMed

Cai, Chunyan; Yuan, Ying; Johnson, Valen E

2013-01-01

Trials of combination therapies for the treatment of cancer are playing an increasingly important role in the battle against this disease. To more efficiently handle the large number of combination therapies that must be tested, we propose a novel Bayesian phase II adaptive screening design to simultaneously select among possible treatment combinations involving multiple agents. Our design is based on formulating the selection procedure as a Bayesian hypothesis testing problem in which the superiority of each treatment combination is equated to a single hypothesis. During the trial conduct, we use the current values of the posterior probabilities of all hypotheses to adaptively allocate patients to treatment combinations. Simulation studies show that the proposed design substantially outperforms the conventional multiarm balanced factorial trial design. The proposed design yields a significantly higher probability for selecting the best treatment while allocating substantially more patients to efficacious treatments. The proposed design is most appropriate for the trials combining multiple agents and screening out the efficacious combination to be further investigated. The proposed Bayesian adaptive phase II screening design substantially outperformed the conventional complete factorial design. Our design allocates more patients to better treatments while providing higher power to identify the best treatment at the end of the trial.

The Differential Effects of Reward on Space- and Object-Based Attentional Allocation

PubMed Central

Shomstein, Sarah

2013-01-01

Estimating reward contingencies and allocating attentional resources to a subset of relevant information are the most important contributors to increasing adaptability of an organism. Although recent evidence suggests that reward- and attention-based guidance recruits overlapping cortical regions and has similar effects on sensory responses, the exact nature of the relationship between the two remains elusive. Here, using event-related fMRI on human participants, we contrasted the effects of reward on space- and object-based selection in the same experimental setting. Reward was either distributed randomly or biased a particular object. Behavioral and neuroimaging results show that space- and object-based attention is influenced by reward differentially. Space-based attentional allocation is mandatory, integrating reward information over time, whereas object-based attentional allocation is a default setting that is completely replaced by the reward signal. Nonadditivity of the effects of reward and object-based attention was observed consistently at multiple levels of analysis in early visual areas as well as in control regions. These results provide strong evidence that space- and object-based allocation are two independent attentional mechanisms, and suggest that reward serves to constrain attentional selection. PMID:23804086

Working memory capacity accounts for the ability to switch between object-based and location-based allocation of visual attention.

PubMed

Bleckley, M Kathryn; Foster, Jeffrey L; Engle, Randall W

2015-04-01

Bleckley, Durso, Crutchfield, Engle, and Khanna (Psychonomic Bulletin & Review, 10, 884-889, 2003) found that visual attention allocation differed between groups high or low in working memory capacity (WMC). High-span, but not low-span, subjects showed an invalid-cue cost during a letter localization task in which the letter appeared closer to fixation than the cue, but not when the letter appeared farther from fixation than the cue. This suggests that low-spans allocated attention as a spotlight, whereas high-spans allocated their attention to objects. In this study, we tested whether utilizing object-based visual attention is a resource-limited process that is difficult for low-span individuals. In the first experiment, we tested the uses of object versus location-based attention with high and low-span subjects, with half of the subjects completing a demanding secondary load task. Under load, high-spans were no longer able to use object-based visual attention. A second experiment supported the hypothesis that these differences in allocation were due to high-spans using object-based allocation, whereas low-spans used location-based allocation.

Experimental evidence of a risk-sensitive reproductive allocation in a long-lived mammal.

PubMed

Bårdsen, Bard-Jørgen; Fauchald, Per; Tveraa, Torkild; Langeland, Knut; Yoccoz, Nigel Gilles; Ims, Rolf Anker

2008-03-01

When reproduction competes with the amount of resources available for survival during an unpredictable nonbreeding season, individuals should adopt a risk-sensitive regulation of their reproductive allocation. We tested this hypothesis on female reindeer (Rangifer tarandus), which face a trade-off between reproduction and acquisition of body reserves during spring and summer, with autumn body mass functioning as insurance against stochastic winter climatic severity. The study was conducted in a population consisting of two herds: one that received supplementary winter feeding for four years while the other utilized natural pastures. The females receiving additional forage allocated more to their calves. Experimental translocation of females between the herds was conducted to simulate two contrasting rapid alterations of winter conditions. When females receiving supplementary feeding were moved to natural pastures, they promptly reduced their reproductive allocation the following summer. However, when winter conditions were improved, females were reluctant to increase their reproductive allocation. This asymmetric response to improved vs. reduced winter conditions is consistent with a risk-averse adjustment in reproductive allocation. The ability of individuals to track their environment and the concordant risk-sensitive adjustment of reproductive allocation may render subarctic reindeer more resilient to climate change than previously supposed.

Mortality affects adaptive allocation to growth and reproduction: field evidence from a guild of body snatchers

PubMed Central

2010-01-01

Background The probability of being killed by external factors (extrinsic mortality) should influence how individuals allocate limited resources to the competing processes of growth and reproduction. Increased extrinsic mortality should select for decreased allocation to growth and for increased reproductive effort. This study presents perhaps the first clear cross-species test of this hypothesis, capitalizing on the unique properties offered by a diverse guild of parasitic castrators (body snatchers). I quantify growth, reproductive effort, and expected extrinsic mortality for several species that, despite being different species, use the same species' phenotype for growth and survival. These are eight trematode parasitic castrators—the individuals of which infect and take over the bodies of the same host species—and their uninfected host, the California horn snail. Results As predicted, across species, growth decreased with increased extrinsic mortality, while reproductive effort increased with increased extrinsic mortality. The trematode parasitic castrator species (operating stolen host bodies) that were more likely to be killed by dominant species allocated less to growth and relatively more to current reproduction than did species with greater life expectancies. Both genders of uninfected snails fit into the patterns observed for the parasitic castrator species, allocating as much to growth and to current reproduction as expected given their probability of reproductive death (castration by trematode parasites). Additionally, species differences appeared to represent species-specific adaptations, not general plastic responses to local mortality risk. Conclusions Broadly, this research illustrates that parasitic castrator guilds can allow unique comparative tests discerning the forces promoting adaptive evolution. The specific findings of this study support the hypothesis that extrinsic mortality influences species differences in growth and reproduction. PMID:20459643

Cost Differentials in State Aid Programs in Selected States.

ERIC Educational Resources Information Center

Jordan, K. Forbis

This paper discusses the merits of cost differentials and weighted-pupil formulas as vehicles for allocating State school support funds to local school districts. The research conducted by the National Educational Finance Project to identify educational program expenditures and to develop cost differentials for each educational program in a…

Prey density and the behavioral flexibility of a marine predator: The common murre (Uria aalge)

USGS Publications Warehouse

Harding, A.M.A.; Piatt, John F.; Schmutz, J.A.; Shultz, M.T.; van Pelt, Thomas I.; Kettle, Arthur B.; Speckman, Suzann G.

2007-01-01

Flexible time budgets allow individual animals to buffer the effects of variable food availability by allocating more time to foraging when food density decreases. This trait should be especially important for marine predators that forage on patchy and ephemeral food resources. We examined flexible time allocation by a long-lived marine predator, the Common Murre (Uria aalge), using data collected in a five-year study at three colonies in Alaska (USA) with contrasting environmental conditions. Annual hydroacoustic surveys revealed an order-of-magnitude variation in food density among the 15 colony-years of study. We used data on parental time budgets and local prey density to test predictions from two hypotheses: Hypothesis A, the colony attendance of seabirds varies nonlinearly with food density; and Hypothesis B, flexible time allocation of parent murres buffers chicks against variable food availability. Hypothesis A was supported; colony attendance by murres was positively correlated with food over a limited range of poor-to-moderate food densities, but independent of food over a broader range of higher densities. This is the first empirical evidence for a nonlinear response of a marine predator's time budget to changes in prey density. Predictions from Hypothesis B were largely supported: (1) chick-feeding rates were fairly constant over a wide range of densities and only dropped below 3.5 meals per day at the low end of prey density, and (2) there was a nonlinear relationship between chick-feeding rates and time spent at the colony, with chick-feeding rates only declining after time at the colony by the nonbrooding parent was reduced to a minimum. The ability of parents to adjust their foraging time by more than 2 h/d explains why they were able to maintain chick-feeding rates of more than 3.5 meals/d across a 10-fold range in local food density. ?? 2007 by the Ecological Society of America.

Adaptive Allocation of Attention: Effects of Sex and Sociosexuality on Visual Attention to Attractive Opposite-Sex Faces.

PubMed

Duncan, Lesley A; Park, Justin H; Faulkner, Jason; Schaller, Mark; Neuberg, Steven L; Kenrick, Douglas T

2007-09-01

We tested the hypothesis that, compared with sociosexually restricted individuals, those with an unrestricted approach to mating would selectively allocate visual attention to attractive opposite-sex others. We also tested for sex differences in this effect. Seventy-four participants completed the Sociosexual Orientation Inventory, and performed a computer-based task that assessed the speed with which they detected changes in attractive and unattractive male and female faces. Differences in reaction times served as indicators of selective attention. Results revealed a Sex X Sociosexuality interaction: Compared with sociosexually restricted men, unrestricted men selectively allocated attention to attractive opposite-sex others; no such effect emerged among women. This finding was specific to opposite-sex targets and did not occur in attention to same-sex others. These results contribute to a growing literature on the adaptive allocation of attention in social environments.

Visual selective attention with virtual barriers.

PubMed

Schneider, Darryl W

2017-07-01

Previous studies have shown that interference effects in the flanker task are reduced when physical barriers (e.g., hands) are placed around rather than below a target flanked by distractors. One explanation of this finding is the referential coding hypothesis, whereby the barriers serve as reference objects for allocating attention. In five experiments, the generality of the referential coding hypothesis was tested by investigating whether interference effects are modulated by the placement of virtual barriers (e.g., parentheses). Modulation of flanker interference was found only when target and distractors differed in size and the virtual barriers were beveled wood-grain objects. Under these conditions and those of previous studies, the author conjectures that an impression of depth was produced when the barriers were around the target, such that the target was perceived to be on a different depth plane than the distractors. Perception of depth in the stimulus display might have led to referential coding of the stimuli in three-dimensional (3-D) space, influencing the allocation of attention beyond the horizontal and vertical dimensions. This 3-D referential coding hypothesis is consistent with research on selective attention in 3-D space that shows flanker interference is reduced when target and distractors are separated in depth.

Differentiated cells are more efficient than adult stem cells for cloning by somatic cell nuclear transfer.

PubMed

Sung, Li-Ying; Gao, Shaorong; Shen, Hongmei; Yu, Hui; Song, Yifang; Smith, Sadie L; Chang, Ching-Chien; Inoue, Kimiko; Kuo, Lynn; Lian, Jin; Li, Ao; Tian, X Cindy; Tuck, David P; Weissman, Sherman M; Yang, Xiangzhong; Cheng, Tao

2006-11-01

Since the creation of Dolly via somatic cell nuclear transfer (SCNT), more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1%-5%) is that the clones are likely to be derived from adult stem cells. Support for this hypothesis comes from the findings that the reproductive cloning efficiency for embryonic stem cells is five to ten times higher than that for somatic cells as donors and that cloned pups cannot be produced directly from cloned embryos derived from differentiated B and T cells or neuronal cells. The question remains as to whether SCNT-derived animal clones can be derived from truly differentiated somatic cells. We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells, progenitor cells and granulocytes. We found that cloning efficiency increases over the differentiation hierarchy, and terminally differentiated postmitotic granulocytes yield cloned pups with the greatest cloning efficiency.

Rail-Highway Crossing Resource Allocation Procedure. User's Guide. 2nd edition.

DOT National Transportation Integrated Search

2006-01-01

This report presents findings from a customer satisfaction study conducted in Cobb County, Georgia. The primary hypothesis of this study is that it is possible to develop customer satisfaction measures that are a reliable determinant of roadway quali...

COMPETITION FOR RESOURCES IN TREES: PHYSIOLOGICAL VERSUS MORPHOLOGICAL PLASTICITY

EPA Science Inventory

In this review we examine two hypotheses related to resource acquisition in trees. The first hypothesis states that when competition is size-asymmetrical, then allocation changes leading to morphological shifts are more important than physiological shifts in obtaining limited re...

Effects of parental care on resource allocation into immune defense and buccal microbiota in mouthbrooding cichlid fishes.

PubMed

Keller, Isabel S; Bayer, Till; Salzburger, Walter; Roth, Olivia

2018-05-01

Sexual dimorphism is founded upon a resource allocation trade-off between investments in reproduction versus other life-history traits including the immune system. In species with conventional parental care roles, theory predicts that males maximize their lifetime reproductive success by allocating resources toward sexual selection, while females achieve this through prolonging their lifespan. Here, we examine the interrelation between sexual dimorphism and parental care strategies in closely related maternal and biparental mouthbrooding cichlid fishes from East African Lake Tanganyika. We measured cellular immune parameters, examined the relative expression of 28 immune system and life history-related candidate genes and analyzed the microbiota composition in the buccal cavity. According to our predictions, maternal mouthbrooders are more sexually dimorphic in immune parameters than biparental mouthbrooders, which has possibly arisen through a differential resource allocation into parental care versus secondary sexual traits. Biparental mouthbrooders, on the other hand, which share the costs of parental care, feature an upregulated adaptive immune response and stronger antiviral properties, while their inflammation response is reduced. Overall, our results suggest a differential resource allocation trade-off between the two modes of parental investment. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Bayesian adaptive phase II screening design for combination trials

PubMed Central

Cai, Chunyan; Yuan, Ying; Johnson, Valen E

2013-01-01

Background Trials of combination therapies for the treatment of cancer are playing an increasingly important role in the battle against this disease. To more efficiently handle the large number of combination therapies that must be tested, we propose a novel Bayesian phase II adaptive screening design to simultaneously select among possible treatment combinations involving multiple agents. Methods Our design is based on formulating the selection procedure as a Bayesian hypothesis testing problem in which the superiority of each treatment combination is equated to a single hypothesis. During the trial conduct, we use the current values of the posterior probabilities of all hypotheses to adaptively allocate patients to treatment combinations. Results Simulation studies show that the proposed design substantially outperforms the conventional multiarm balanced factorial trial design. The proposed design yields a significantly higher probability for selecting the best treatment while allocating substantially more patients to efficacious treatments. Limitations The proposed design is most appropriate for the trials combining multiple agents and screening out the efficacious combination to be further investigated. Conclusions The proposed Bayesian adaptive phase II screening design substantially outperformed the conventional complete factorial design. Our design allocates more patients to better treatments while providing higher power to identify the best treatment at the end of the trial. PMID:23359875

Ethnic Variation in Classroom Interaction: Myth or Reality.

ERIC Educational Resources Information Center

Kumaravadivelu, B.

1990-01-01

A study of ethnic variation supports the hypothesis that rules/norms governing second-language classroom interactional patterns are affected by the teacher's pedagogical orientation and turn allocation management, learner disposition/motivation toward participation, and interactional opportunities. It cautions against hasty linkages between…

Flexibility of resource allocation in a hermaphroditic-gynomonoecious herb through deployment of female and male resources in perfect flowers.

PubMed

Mamut, Jannathan; Xiong, Ying-Ze; Tan, Dun-Yan; Huang, Shuang-Quan

2017-03-01

It has been hypothesized that two flower types permit flexible allocation of resources to female and male functions, yet empirical evidence for the sex-allocation hypothesis remains scarce in gynomonoecious species. To characterize resource allocation to pistillate and perfect flowers and allocation of perfect flowers between gynomonoecious and hermaphroditic individuals, we examined the flexibility and whether female-biased allocation increases with plant size in the hermaphroditic-gynomonoecious herb Eremurus anisopterus . Frequency of gynomonoecious individuals, flower production, and plant size were investigated in different populations. Floral allocation was compared among the three flower types of E. anisopterus . Frequency of gynomonoecious plants varied from 2-17% in nine populations. Only larger plants produced female flowers at the bottom of racemes. Both female and perfect flower production tended to increase proportionately with plant size in gynomonoecious individuals. Female flowers did not produce less biomass than perfect flowers from hermaphroditic or gynomonoecious plants. However, both female and perfect flowers from gynomonoecious individuals had lighter stamen mass, but larger pistil mass, than perfect flowers from hermaphrodites. Although the prediction of an increase in female flower number with plant size was not observed in E. anisopterus , the flexibility of sex allocation in gynomonoecious species was confirmed in that gynomonoecious individuals had a female-biased floral allocation compared to hermaphroditic individuals. Such comparisons of gynomonoecious to hermaphroditic individuals permit us to unveil a sexual adjustment strategy: flexibility of sexual investments within plants. © 2017 Botanical Society of America.

From Districts to Schools: The Distribution of Resources across Schools in Big City School Districts

ERIC Educational Resources Information Center

Rubenstein, Ross; Schwartz, Amy Ellen; Stiefel, Leanna; Amor, Hella Bel Hadj

2007-01-01

While the distribution of resources across school districts is well studied, relatively little attention has been paid to how resources are allocated to individual schools inside those districts. This paper explores the determinants of resource allocation across schools in large districts based on factors that reflect differential school costs or…

Social dominance explains within-ejaculate variation in sperm design in a passerine bird.

PubMed

Rojas Mora, Alfonso; Meniri, Magali; Ciprietti, Sabrina; Helfenstein, Fabrice

2017-03-04

Comparative studies suggest that sperm competition exerts stabilizing selection towards an optimal sperm design - e.g., the relative size and covariation of different sperm sections or a quantitative measure of sperm shape - that maximizes male fertility, which results in reduced levels of within-male variation in sperm morphology. Yet, these studies also reveal substantial amounts of unexplained within-ejaculate variance, and the factors presiding to the maintenance of such within-male variation in sperm design at the population level still remain to be identified. Sperm competition models predict that males should progressively invest more resources in their germline as their mating costs increase, i.e., the soma/germline allocation trade-off hypothesis. When access to fertile females is determined by social dominance, the soma/germline allocation trade-off hypothesis predicts that dominant males should invest less in the control of spermatogenesis. Hence, dominance should positively correlate with within-male variance in sperm design. In support of this hypothesis, we found that dominant house sparrow males produce ejaculates with higher levels of within-ejaculate variation in sperm design compared to subordinate males. However, after experimentally manipulating male social status, this pattern was not maintained. Our results suggest that males might control variation in sperm design according to their social status to some extent. Yet, it seems that such within-ejaculate variation in sperm design cannot be rapidly adjusted to a new status. While variation in sperm design could result from various non-exclusive sources, we discuss how strategic allocation of resources to the somatic vs. the germline functions could be an important process shaping the relationship between within-male variation in sperm design and social status.

Visual short-term memory load reduces retinotopic cortex response to contrast.

PubMed

Konstantinou, Nikos; Bahrami, Bahador; Rees, Geraint; Lavie, Nilli

2012-11-01

Load Theory of attention suggests that high perceptual load in a task leads to reduced sensory visual cortex response to task-unrelated stimuli resulting in "load-induced blindness" [e.g., Lavie, N. Attention, distraction and cognitive control under load. Current Directions in Psychological Science, 19, 143-148, 2010; Lavie, N. Distracted and confused?: Selective attention under load. Trends in Cognitive Sciences, 9, 75-82, 2005]. Consideration of the findings that visual STM (VSTM) involves sensory recruitment [e.g., Pasternak, T., & Greenlee, M. Working memory in primate sensory systems. Nature Reviews Neuroscience, 6, 97-107, 2005] within Load Theory led us to a new hypothesis regarding the effects of VSTM load on visual processing. If VSTM load draws on sensory visual capacity, then similar to perceptual load, high VSTM load should also reduce visual cortex response to incoming stimuli leading to a failure to detect them. We tested this hypothesis with fMRI and behavioral measures of visual detection sensitivity. Participants detected the presence of a contrast increment during the maintenance delay in a VSTM task requiring maintenance of color and position. Increased VSTM load (manipulated by increased set size) led to reduced retinotopic visual cortex (V1-V3) responses to contrast as well as reduced detection sensitivity, as we predicted. Additional visual detection experiments established a clear tradeoff between the amount of information maintained in VSTM and detection sensitivity, while ruling out alternative accounts for the effects of VSTM load in terms of differential spatial allocation strategies or task difficulty. These findings extend Load Theory to demonstrate a new form of competitive interactions between early visual cortex processing and visual representations held in memory under load and provide a novel line of support for the sensory recruitment hypothesis of VSTM.

Prey risk allocation in a grazing ecosystem.

PubMed

Gude, Justin A; Garrott, Robert A; Borkowski, John J; King, Fred

2006-02-01

Understanding the behaviorally mediated indirect effects of predators in ecosystems requires knowledge of predator-prey behavioral interactions. In predator-ungulate-plant systems, empirical research quantifying how predators affect ungulate group sizes and distribution, in the context of other influential variables, is particularly needed. The risk allocation hypothesis proposes that prey behavioral responses to predation risk depend on background frequencies of exposure to risk, and it can be used to make predictions about predator-ungulate-plant interactions. We determined non-predation variables that affect elk (Cervus elaphus) group sizes and distribution on a winter range in the Greater Yellowstone Ecosystem (GYE) using logistic and log-linear regression on surveys of 513 1-km2 areas conducted over two years. Employing model selection techniques, we evaluated risk allocation and other a priori hypotheses of elk group size and distributional responses to wolf (Canis lupus) predation risk while accounting for influential non-wolf-predation variables. We found little evidence that wolves affect elk group sizes, which were strongly influenced by habitat type and hunting by humans. Following predictions from the risk allocation hypothesis, wolves likely created a more dynamic elk distribution in areas that they frequently hunted, as elk tended to move following wolf encounters in those areas. This response should dilute elk foraging pressure on plant communities in areas where they are frequently hunted by wolves. We predict that this should decrease the spatial heterogeneity of elk impacts on grasslands in areas that wolves frequently hunt. We also predict that this should decrease browsing pressure on heavily browsed woody plant stands in certain areas, which is supported by recent research in the GYE.

Perceptual grouping allows for attention to cover noncontiguous locations and suppress capture from nearby locations.

PubMed

Kerzel, Dirk; Born, Sabine; Schönhammer, Josef

2012-12-01

A salient stimulus may interrupt visual search because of attentional capture. It has been shown that attentional capture occurs with a wide, but not with a small attentional window. We tested the hypothesis that capture depends more strongly on the shape of the attentional window than on its size. Search elements were arranged in two nested rings. The ring containing the search target remained fixed, while a salient color singleton occurred either in the same or in the other ring. We observed that color singletons only disrupted search when shown in the same ring as the search target. It is important to note that, when focusing on the outer array, which presumably required a larger attentional window, singletons on the inner array did not capture attention. In contrast to the original attentional window hypothesis, our results show that attentional capture does not always occur with a large attentional window. Rather, attention can be flexibly allocated to the set of relevant stimulus locations and attentional capture is confined to the attended locations. Further experiments showed that attention was allocated to search elements that were perceptually grouped into "whole" or "Gestalt"-like objects, which prevented attentional capture from nearby locations. However, when attention was allocated to noncontiguous locations that did not form a perceptual Gestalt, nearby locations elicited attentional capture. Perceptual grouping could be based on a combination of color and position, but not on color alone. Thus, the allocation of attention to Gestalt-like objects that were jointly defined by similarity and proximity prevented attentional capture from nearby locations.

Dementia and Depression: A Process Model for Differential Diagnosis.

ERIC Educational Resources Information Center

Hill, Carrie L.; Spengler, Paul M.

1997-01-01

Delineates a process model for mental-health counselors to follow in formulating a differential diagnosis of dementia and depression in adults 65 years and older. The model is derived from empirical, theoretical, and clinical sources of evidence. Explores components of the clinical interview, of hypothesis formation, and of hypothesis testing.…

Testing the optimal defence hypothesis for two indirect defences: extrafloral nectar and volatile organic compounds

PubMed Central

Radhika, Venkatesan; Kost, Christian; Bartram, Stefan; Heil, Martin

2008-01-01

Many plants respond to herbivory with an increased production of extrafloral nectar (EFN) and/or volatile organic compounds (VOCs) to attract predatory arthropods as an indirect defensive strategy. In this study, we tested whether these two indirect defences fit the optimal defence hypothesis (ODH), which predicts the within-plant allocation of anti-herbivore defences according to trade-offs between growth and defence. Using jasmonic acid-induced plants of Phaseolus lunatus and Ricinus communis, we tested whether the within-plant distribution pattern of these two indirect defences reflects the fitness value of the respective plant parts. Furthermore, we quantified photosynthetic rates and followed the within-plant transport of assimilates with 13C labelling experiments. EFN secretion and VOC emission were highest in younger leaves. Moreover, the photosynthetic rate increased with leaf age, and pulse-labelling experiments suggested transport of carbon to younger leaves. Our results demonstrate that the ODH can explain the within-plant allocation pattern of both indirect defences studied. PMID:18493790

Testing the depth-differentiation hypothesis in a deepwater octocoral

USGS Publications Warehouse

Quattrini, Andrea; Baums, Iliana B.; Shank, Timothy M.; Morrison, Cheryl L.; Cordes, Erik E.

2015-01-01

The depth-differentiation hypothesis proposes that the bathyal region is a source of genetic diversity and an area where there is a high rate of species formation. Genetic differentiation should thus occur over relatively small vertical distances, particularly along the upper continental slope (200–1000 m) where oceanography varies greatly over small differences in depth. To test whether genetic differentiation within deepwater octocorals is greater over vertical rather than geographical distances, Callogorgia delta was targeted. This species commonly occurs throughout the northern Gulf of Mexico at depths ranging from 400 to 900 m. We found significant genetic differentiation (FST = 0.042) across seven sites spanning 400 km of distance and 400 m of depth. A pattern of isolation by depth emerged, but geographical distance between sites may further limit gene flow. Water mass boundaries may serve to isolate populations across depth; however, adaptive divergence with depth is also a possible scenario. Microsatellite markers also revealed significant genetic differentiation (FST = 0.434) between C. delta and a closely related species, Callogorgia americana, demonstrating the utility of microsatellites in species delimitation of octocorals. Results provided support for the depth-differentiation hypothesis, strengthening the notion that factors covarying with depth serve as isolation mechanisms in deep-sea populations.

Relative time sharing: new findings and an extension of the resource allocation model of temporal processing.

PubMed

Buhusi, Catalin V; Meck, Warren H

2009-07-12

Individuals time as if using a stopwatch that can be stopped or reset on command. Here, we review behavioural and neurobiological data supporting the time-sharing hypothesis that perceived time depends on the attentional and memory resources allocated to the timing process. Neuroimaging studies in humans suggest that timekeeping tasks engage brain circuits typically involved in attention and working memory. Behavioural, pharmacological, lesion and electrophysiological studies in lower animals support this time-sharing hypothesis. When subjects attend to a second task, or when intruder events are presented, estimated durations are shorter, presumably due to resources being taken away from timing. Here, we extend the time-sharing hypothesis by proposing that resource reallocation is proportional to the perceived contrast, both in temporal and non-temporal features, between intruders and the timed events. New findings support this extension by showing that the effect of an intruder event is dependent on the relative duration of the intruder to the intertrial interval. The conclusion is that the brain circuits engaged by timekeeping comprise not only those primarily involved in time accumulation, but also those involved in the maintenance of attentional and memory resources for timing, and in the monitoring and reallocation of those resources among tasks.

Word Learning and Attention Allocation Based on Word Class and Category Knowledge

ERIC Educational Resources Information Center

Hupp, Julie M.

2015-01-01

Attention allocation in word learning may vary developmentally based on the novelty of the object. It has been suggested that children differentially learn verbs based on the novelty of the agent, but adults do not because they automatically infer the object's category and thus treat it like a familiar object. The current research examined…

Appraisal of Space Words and Allocation of Emotion Words in Bodily Space

PubMed Central

Marmolejo-Ramos, Fernando; Elosúa, María Rosa; Yamada, Yuki; Hamm, Nicholas Francis; Noguchi, Kimihiro

2013-01-01

The body-specificity hypothesis (BSH) predicts that right-handers and left-handers allocate positive and negative concepts differently on the horizontal plane, i.e., while left-handers allocate negative concepts on the right-hand side of their bodily space, right-handers allocate such concepts to the left-hand side. Similar research shows that people, in general, tend to allocate positive and negative concepts in upper and lower areas, respectively, in relation to the vertical plane. Further research shows a higher salience of the vertical plane over the horizontal plane in the performance of sensorimotor tasks. The aim of the paper is to examine whether there should be a dominance of the vertical plane over the horizontal plane, not only at a sensorimotor level but also at a conceptual level. In Experiment 1, various participants from diverse linguistic backgrounds were asked to rate the words “up”, “down”, “left”, and “right”. In Experiment 2, right-handed participants from two linguistic backgrounds were asked to allocate emotion words into a square grid divided into four boxes of equal areas. Results suggest that the vertical plane is more salient than the horizontal plane regarding the allocation of emotion words and positively-valenced words were placed in upper locations whereas negatively-valenced words were placed in lower locations. Together, the results lend support to the BSH while also suggesting a higher saliency of the vertical plane over the horizontal plane in the allocation of valenced words. PMID:24349112

Genetic Dissection of Nutrition-Induced Plasticity in Insulin/Insulin-Like Growth Factor Signaling and Median Life Span in a Drosophila Multiparent Population

PubMed Central

Stanley, Patrick D.; Ng’oma, Enoch; O’Day, Siri; King, Elizabeth G.

2017-01-01

The nutritional environments that organisms experience are inherently variable, requiring tight coordination of how resources are allocated to different functions relative to the total amount of resources available. A growing body of evidence supports the hypothesis that key endocrine pathways play a fundamental role in this coordination. In particular, the insulin/insulin-like growth factor signaling (IIS) and target of rapamycin (TOR) pathways have been implicated in nutrition-dependent changes in metabolism and nutrient allocation. However, little is known about the genetic basis of standing variation in IIS/TOR or how diet-dependent changes in expression in this pathway influence phenotypes related to resource allocation. To characterize natural genetic variation in the IIS/TOR pathway, we used >250 recombinant inbred lines (RILs) derived from a multiparental mapping population, the Drosophila Synthetic Population Resource, to map transcript-level QTL of genes encoding 52 core IIS/TOR components in three different nutritional environments [dietary restriction (DR), control (C), and high sugar (HS)]. Nearly all genes, 87%, were significantly differentially expressed between diets, though not always in ways predicted by loss-of-function mutants. We identified cis (i.e., local) expression QTL (eQTL) for six genes, all of which are significant in multiple nutrient environments. Further, we identified trans (i.e., distant) eQTL for two genes, specific to a single nutrient environment. Our results are consistent with many small changes in the IIS/TOR pathways. A discriminant function analysis for the C and DR treatments identified a pattern of gene expression associated with the diet treatment. Mapping the composite discriminant function scores revealed a significant global eQTL within the DR diet. A correlation between the discriminant function scores and the median life span (r = 0.46) provides evidence that gene expression changes in response to diet are associated with longevity in these RILs. PMID:28592498

Peanut canopy temperature and NDVI response to varying irrigation rates

USDA-ARS?s Scientific Manuscript database

Variable rate irrigation (VRI) systems have the potential to conserve water by spatially allocating limited water resources. In this study, peanut was grown under a VRI system to evaluate the impact of differential irrigation rates on peanut yield. Additionally, we evaluated the impact of differenti...

Reproductive Allocation of Biomass and Nitrogen in Annual and Perennial Lesquerella Crops

PubMed Central

PLOSCHUK, E. L.; SLAFER, G. A.; RAVETTA, D. A.

2005-01-01

• Background and Aims The use of perennial crops could contribute to increase agricultural sustainability. However, almost all of the major grain crops are herbaceous annuals and opportunities to replace them with more long-lived perennials have been poorly explored. This follows the presumption that the perennial life cycle is associated with a lower potential yield, due to a reduced allocation of biomass to grains. The hypothesis was tested that allocation to perpetuation organs in the perennial L. mendocina would not be directly related to a lower allocation to seeds. • Methods Two field experiments were carried on with the annual Lesquerella fendleri and the iteroparous perennial L. mendocina, two promising oil-seed crops for low-productivity environments, subjected to different water and nitrogen availability. • Key Results Seed biomass allocation was similar for both species, and unresponsive to water and nitrogen availability. Greater root and vegetative shoot allocation in the perennial was counterbalanced by a lower allocation to other reproductive structures compared with the annual Lesquerella. Allometric relationships revealed that allocation differences between the annual and the perennial increased linearly with plant size. The general allocation patterns for nitrogen did not differ from those of biomass. However, nitrogen concentrations were higher in the vegetative shoot and root of L. mendocina than of L. fendleri but remained stable in seeds of both species. • Conclusions It is concluded that vegetative organs are more hierarchically important sinks in L. mendocina than in the annual L. fendleri, but without disadvantages in seed hierarchy. PMID:15863469

Molecular and Cellular Mechanisms for Trapping and Activating Emotional Memories

PubMed Central

Cai, Denise J.; Sano, Yoshitake; Lee, Yong-Seok; Zhou, Yu; Bekal, Pallavi; Deisseroth, Karl; Silva, Alcino J.

2016-01-01

Recent findings suggest that memory allocation to specific neurons (i.e., neuronal allocation) in the amygdala is not random, but rather the transcription factor cAMP-response element binding protein (CREB) modulates this process, perhaps by regulating the transcription of channels that control neuronal excitability. Here, optogenetic studies in the mouse lateral amygdala (LA) were used to demonstrate that CREB and neuronal excitability regulate which neurons encode an emotional memory. To test the role of CREB in memory allocation, we overexpressed CREB in the lateral amygdala to recruit the encoding of an auditory-fear conditioning (AFC) memory to a subset of neurons. Then, post-training activation of these neurons with Channelrhodopsin-2 was sufficient to trigger recall of the memory for AFC, suggesting that CREB regulates memory allocation. To test the role of neuronal excitability in memory allocation, we used a step function opsin (SFO) to transiently increase neuronal excitability in a subset of LA neurons during AFC. Post-training activation of these neurons with Volvox Channelrhodopsin-1 was able to trigger recall of that memory. Importantly, our studies show that activation of the SFO did not affect AFC by either increasing anxiety or by strengthening the unconditioned stimulus. Our findings strongly support the hypothesis that CREB regulates memory allocation by modulating neuronal excitability. PMID:27579481

Semester-Long Inquiry-Based Molecular Biology Laboratory: Transcriptional Regulation in Yeast

ERIC Educational Resources Information Center

Oelkers, Peter M.

2017-01-01

A single semester molecular biology laboratory has been developed in which students design and execute a project examining transcriptional regulation in "Saccharomyces cerevisiae." Three weeks of planning are allocated to developing a hypothesis through literature searches and use of bioinformatics. Common experimental plans address a…

The Impact of Education on Health Knowledge

ERIC Educational Resources Information Center

Altindag, Duha; Cannonier, Colin; Mocan, Naci

2011-01-01

The theory on the demand for health suggests that schooling causes health because schooling increases the efficiency of health production. Alternatively, the allocative efficiency hypothesis argues that schooling alters the input mix chosen to produce health. This suggests that the more educated have more knowledge about the health production…

On the Efficient Allocation of Resources for Hypothesis Evaluation in Machine Learning: A Statistical Approach

NASA Technical Reports Server (NTRS)

Chien, S.; Gratch, J.; Burl, M.

1994-01-01

In this report we consider a decision-making problem of selecting a strategy from a set of alternatives on the basis of incomplete information (e.g., a finite number of observations): the system can, however, gather additional information at some cost.

Distributed Multiple Access Control for the Wireless Mesh Personal Area Networks

NASA Astrophysics Data System (ADS)

Park, Moo Sung; Lee, Byungjoo; Rhee, Seung Hyong

Mesh networking technologies for both high-rate and low-rate wireless personal area networks (WPANs) are under development by several standardization bodies. They are considering to adopt distributed TDMA MAC protocols to provide seamless user mobility as well as a good peer-to-peer QoS in WPAN mesh. It has been, however, pointed out that the absence of a central controller in the wireless TDMA MAC may cause a severe performance degradation: e. g., fair allocation, service differentiation, and admission control may be hard to achieve or can not be provided. In this paper, we suggest a new framework of resource allocation for the distributed MAC protocols in WPANs. Simulation results show that our algorithm achieves both a fair resource allocation and flexible service differentiations in a fully distributed way for mesh WPANs where the devices have high mobility and various requirements. We also provide an analytical modeling to discuss about its unique equilibrium and to compute the lengths of reserved time slots at the stable point.

Sex-biased investment in yolk androgens depends on female quality and laying order in zebra finches (Taeniopygia guttata)

NASA Astrophysics Data System (ADS)

Gilbert, Lucy; Rutstein, Alison N.; Hazon, Neil; Graves, Jefferson A.

2005-04-01

The Trivers-Willard hypothesis predicts sex biases in parental investment according to parental condition. In addition, parents may need to sex bias their investment if there is an asymmetry between the sexes in offspring fitness under different conditions. For studying maternal differential investment, egg resources are ideal subjects because they are self contained and allocated unequivocally by the female. Recent studies show that yolk androgens can be beneficial to offspring, so here we test for sex-biased investment with maternal investment of yolk testosterone (T) in zebra finch (Taeniopygia guttata) eggs. From the Trivers-Willard hypothesis, we predicted females to invest more in male eggs in optimum circumstances (e.g. good-condition mother, early-laid egg), and more in female eggs under suboptimal conditions (e.g. poor-condition mother, late-laid egg). This latter prediction is also because in this species there is a female nestling disadvantage in poor conditions and we expected mothers to help compensate for this in female eggs. Indeed, we found more yolk T in female than male eggs. Moreover, in accordance with our predictions, yolk T in male eggs increased with maternal quality relative to female eggs, and decreased with laying order relative to female eggs. This supports our predictions for the different needs and value of male and female offspring in zebra finches. Our results support the idea that females may use yolk androgens as a tool to adaptively manipulate the inequalities between different nestlings.

Ontogenetic differences of herbivory on woody and herbaceous plants: a meta-analysis demonstrating unique effects of herbivory on the young and the old, the slow and the fast.

PubMed

Massad, Tara Joy

2013-05-01

The effect of herbivory on plant performance is the subject of a large number of ecological studies, and plant responses to herbivory range from reduced reproduction to overcompensation. Because plant defenses, stored resources, and allocation demands change throughout a plant's lifetime, it can be hypothesized the effects of herbivory also vary with development. The present work extends previous analyses to incorporate hundreds of studies in a new meta-analysis addressing this topic. Herbivores had an overall negative effect on plant growth and reproduction, and, in contrast to a previous meta-analysis, this work shows the timing of herbivory is relevant. Differences in the effects of herbivory between life stages existed for woody plant reproduction and perennial herb growth. In addition, tree and shrub growth was reduced by herbivore damage at early ontogenetic stages, and perennial herb reproduction was limited by adult stage herbivory. These results partially support the continuum of an ontogenetic response model. Finally, consideration of this synthesis in conjunction with other work led to the conclusion that different plant groups optimize their defense investments in unique ways. Slow-growing plants may strongly chemically defend young tissues, supporting the plant-age hypothesis, because early herbivory is detrimental to growth. Faster-growing herbs may invest more in antiherbivore defense when they are older, supporting the growth-differentiation balance hypothesis, because later herbivory limits their reproduction.

Allocation to male vs female floral function varies by currency and responds differentially to density and moisture stress.

PubMed

Brock, M T; Winkelman, R L; Rubin, M J; Edwards, C E; Ewers, B E; Weinig, C

2017-11-01

Allocation of finite resources to separate reproductive functions is predicted to vary across environments and affect fitness. Biomass is the most commonly measured allocation currency; however, in comparison with nutrients it may be less limited and express different environmental and evolutionary responses. Here, we measured carbon, nitrogen, phosphorus, and biomass allocation among floral whorls in recombinant inbred lines of Brassica rapa in multiple environments to characterize the genetic architecture of floral allocation, including its sensitivity to environmental heterogeneity and to choice of currency. Mass, carbon, and nitrogen allocation to female whorls (pistils and sepals) decreased under high density, whereas nitrogen allocation to male organs (stamens) decreased under drought. Phosphorus allocation decreased by half in pistils under drought, while stamen phosphorus was unaffected by environment. While the contents of each currency were positively correlated among whorls, selection to improve fitness through female (or male) function typically favored increased allocation to pistils (or stamens) but decreased allocation to other whorls. Finally, genomic regions underlying correlations among allocation metrics were mapped, and loci related to nitrogen uptake and floral organ development were located within mapped quantitative trait loci. Our candidate gene identification suggests that nutrient uptake may be a limiting step in maintaining male allocation. Taken together, allocation to male vs female function is sensitive to distinct environmental stresses, and the choice of currency affects the interpretation of floral allocation responses to the environment. Further, genetic correlations may counter the evolution of allocation patterns that optimize fitness through female or male function.

Brood division in birds in relation to offspring size: sibling rivalry and parental control

PubMed

Slagsvold

1997-12-01

In some altricial birds with biparental care, it is the female, and in others the male, that provides more food to the smallest offspring within the brood. Many hypotheses have been proposed to account for such puzzling patterns of parental care. A parsimonious explanation is that no difference exists between the parents in priority of care but that differences arise simply from sibling rivalry, with dominant chicks trying to position themselves closest to the parent that provides most care (the sibling rivalry hypothesis). A refinement of the idea is that parents use the way they approach the chicks to counter selfish offspring and in this way control allocation of care (the parental approaching hypothesis). A comparison across species suggested that female care of the smallest chick within a brood is the ancestral and most common pattern. However, strong variation exists within single populations. In one species, the American robin, Turdus migratorius the sibling rivalry hypothesis and the parental approaching hypothesis were both supported because in broods where males provided more care than females, the largest chick was predominantly fed by the male whereas the smallest chick was predominantly fed by the female. When the male provided less care than the female, an opposite result was found. The same patterns of allocation of care also seemed to exist when chicks were quite immobile just after having left the nest and when their positions were experimentally controlled, suggesting parental control.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.

Monoamine Oxidase A (MAOA) and Catechol-O-Methyltransferase (COMT) Gene Polymorphisms Interact with Maternal Parenting in Association with Adolescent Reactive Aggression but not Proactive Aggression: Evidence of Differential Susceptibility.

PubMed

Zhang, Wenxin; Cao, Cong; Wang, Meiping; Ji, Linqin; Cao, Yanmiao

2016-04-01

To date, whether and how gene-environment (G × E) interactions operate differently across distinct subtypes of aggression remains untested. More recently, in contrast with the diathesis-stress hypothesis, an alternative hypothesis of differential susceptibility proposes that individuals could be differentially susceptible to environments depending on their genotypes in a "for better and for worse" manner. The current study examined interactions between monoamine oxidase A (MAOA) T941G and catechol-O-methyltransferase (COMT) Val158Met polymorphisms with maternal parenting on two types of aggression: reactive and proactive. Moreover, whether these potential G × E interactions would be consistent with the diathesis-stress versus the differential susceptibility hypothesis was tested. Within the sample of 1399 Chinese Han adolescents (47.2 % girls, M age = 12.32 years, SD = 0.50), MAOA and COMT genes both interacted with positive parenting in their associations with reactive but not proactive aggression. Adolescents with T alleles/TT homozygotes of MAOA gene or Met alleles of COMT gene exhibited more reactive aggression when exposed to low positive parenting, but less reactive aggression when exposed to high positive parenting. These findings provide the first evidence for distinct G × E interaction effects on reactive versus proactive aggression and lend further support for the differential susceptibility hypothesis.

SLA-aware differentiated QoS in elastic optical networks

NASA Astrophysics Data System (ADS)

Agrawal, Anuj; Vyas, Upama; Bhatia, Vimal; Prakash, Shashi

2017-07-01

The quality of service (QoS) offered by optical networks can be improved by accurate provisioning of service level specifications (SLSs) included in the service level agreement (SLA). A large number of users coexisting in the network require different services. Thus, a pragmatic network needs to offer a differentiated QoS to a variety of users according to the SLA contracted for different services at varying costs. In conventional wavelength division multiplexed (WDM) optical networks, service differentiation is feasible only for a limited number of users because of its fixed-grid structure. Newly introduced flex-grid based elastic optical networks (EONs) are more adaptive to traffic requirements as compared to the WDM networks because of the flexibility in their grid structure. Thus, we propose an efficient SLA provisioning algorithm with improved QoS for these flex-grid EONs empowered by optical orthogonal frequency division multiplexing (O-OFDM). The proposed algorithm, called SLA-aware differentiated QoS (SADQ), employs differentiation at the level of routing, spectrum allocation, and connection survivability. The proposed SADQ aims to accurately provision the SLA using such multilevel differentiation with an objective to improve the spectrum utilization from the network operator's perspective. SADQ is evaluated for three different CoSs under various traffic demand patterns and for different ratios of the number of requests belonging to the three considered CoSs. We propose two new SLA metrics for the improvement of functional QoS requirements, namely, security, confidentiality and survivability of high class of service (CoS) traffic. Since, to the best of our knowledge, the proposed SADQ is the first scheme in optical networks to employ exhaustive differentiation at the levels of routing, spectrum allocation, and survivability in a single algorithm, we first compare the performance of SADQ in EON and currently deployed WDM networks to assess the differentiation capability of EON and WDM networks under such differentiated service environment. The proposed SADQ is then compared with two existing benchmark routing and spectrum allocation (RSA) schemes that are also designed under EONs. Simulations indicate that the performance of SADQ is distinctly better in EON than in WDM network under differentiated QoS scenario. The comparative analysis of the proposed SADQ with the considered benchmark RSA strategies designed under EON shows the improved performance of SADQ in EON paradigm for offering differentiated services as per the SLA.

Age Differences in the Effects of Conceptual Integration Training on Resource Allocation in Sentence Processing

PubMed Central

Stine-Morrow, Elizabeth A. L.; Noh, Soo Rim; Shake, Matthew C.

2009-01-01

This research examined age differences in the accommodation of reading strategies as a consequence of explicit instruction in conceptual integration. In Experiment 1, young, middle-aged, and older adults read sentences for delayed recall using a moving window method. Readers in an experimental group received instruction in making conceptual links during reading while readers in a control group were simply encouraged to allocate effort. Regression analysis to decompose word-by-word reading times in each condition isolated the time allocated to conceptual processing at the point in the text at which new concepts were introduced, as well as at clause and sentence boundaries. While younger adults responded to instructions by differentially allocating effort to sentence wrap-up, older adults allocated effort to intrasentence wrap-up and on new concepts as they were introduced, suggesting that older readers optimized their allocation of effort to linguistic computations for textbase construction within their processing capacity. Experiment 2 verified that conceptual integration training improved immediate recall among older readers as a consequence of engendering allocation to conceptual processing. PMID:19941199

Sex differences in cognitive ageing: testing predictions derived from life-history theory in a dioecious nematode.

PubMed

Zwoinska, Martyna K; Kolm, Niclas; Maklakov, Alexei A

2013-12-01

Life-history theory maintains that organisms allocate limited resources to different traits to maximize fitness. Learning ability and memory are costly and known to trade-off with longevity in invertebrates. However, since the relationship between longevity and fitness often differs between the sexes, it is likely that sexes will differentially resolve the trade-off between learning and longevity. We used an established associative learning paradigm in the dioecious nematode Caenorhabditis remanei, which is sexually dimorphic for lifespan, to study age-related learning ability in males and females. In particular, we tested the hypothesis that females (the shorter-lived sex) show higher learning ability than males early in life but senesce faster. Indeed, young females outperformed young males in learning a novel association between an odour (butanone) and food (bacteria). However, while learning ability and offspring production declined rapidly with age in females, males maintained high levels of these traits until mid-age. These results not only demonstrate sexual dimorphism in age-related learning ability but also suggest that it conforms to predictions derived from the life-history theory. © 2013.

Parts, cavities, and object representation in infancy.

PubMed

Hayden, Angela; Bhatt, Ramesh S; Kangas, Ashley; Zieber, Nicole

2011-02-01

Part representation is not only critical to object perception but also plays a key role in a number of basic visual cognition functions, such as figure-ground segregation, allocation of attention, and memory for shapes. Yet, virtually nothing is known about the development of part representation. If parts are fundamental components of object shape representation early in life, then the infant visual system should give priority to parts over other aspects of objects. We tested this hypothesis by examining whether part shapes are more salient than cavity shapes to infants. Five-month-olds were habituated to a stimulus that contained a part and a cavity. In a subsequent novelty preference test, 5-month-olds exhibited a preference for the cavity shape, indicating that part shapes were more salient than cavity shapes during habituation. The differential processing of part versus cavity contours in infancy is consistent with theory and empirical findings in the literature on adult figure-ground perception and indicates that basic aspects of part-based object processing are evident early in life. (c) 2010 APA, all rights reserved.

Winning by a neck: tall giraffes avoid competing with shorter browsers.

PubMed

Cameron, Elissa Z; du Toit, Johan T

2007-01-01

With their vertically elongated body form, giraffes generally feed above the level of other browsers within the savanna browsing guild, despite having access to foliage at lower levels. They ingest more leaf mass per bite when foraging high in the tree, perhaps because smaller, more selective browsers deplete shoots at lower levels or because trees differentially allocate resources to promote shoot growth in the upper canopy. We erected exclosures around individual Acacia nigrescens trees in the greater Kruger ecosystem, South Africa. After a complete growing season, we found no differences in leaf biomass per shoot across height zones in excluded trees but significant differences in control trees. We conclude that giraffes preferentially browse at high levels in the canopy to avoid competition with smaller browsers. Our findings are analogous with those from studies of grazing guilds and demonstrate that resource partitioning can be driven by competition when smaller foragers displace larger foragers from shared resources. This provides the first experimental support for the classic evolutionary hypothesis that vertical elongation of the giraffe body is an outcome of competition within the browsing ungulate guild.

Reproductive investment when mate quality varies: differential allocation versus reproductive compensation.

PubMed

Harris, W Edwin; Uller, Tobias

2009-04-27

Reproductive investment decisions form an integral part of life-history biology. Selection frequently favours plasticity in investment that can generate maternal effects on offspring development. For example, if females differentially allocate resources based on mate attractiveness or quality, this can create a non-genetic link between mate attractiveness and offspring fitness with potential consequences for ecological and evolutionary dynamics. It is therefore important to understand under what conditions differential investment into offspring in relation to male quality is expected to occur and the direction of the effect. Two opposite predictions, increased investment into offspring produced with high-quality mates (differential allocation (DA)) and increased investment with low-quality males (reproductive compensation (RC)) have been suggested but no formal theoretical treatment justifying the assumptions underlying these two hypotheses has been conducted to date. Here, we used a state-based approach to investigate the circumstances under which the variation in mate quality results in differential female investment into offspring and how this interacts with female energetic resource levels. We found that a pattern of increased investment when mating with high-quality mates (i.e. DA) was the most common optimal investment strategy for females in our model. By contrast, increased investment when mating with low-quality mates (i.e. RC) was predicted only when the relative impact of parental investment on offspring quality was low. Finally, we found that the specific pattern of investment in relation to male quality depends on female energetic state, the likelihood for future mating opportunities and the expected future distribution of mate quality. Thus, the female's age and body condition should be important factors mediating DA and RC, which may help to explain the equivocal results of empirical studies.

Resource allocation in Copaifera langsdorffii (Fabaceae): how supra-annual fruiting affects plant traits and herbivory?

PubMed

da Costa, Fernanda Vieira; de Queiroz, Antônio César Medeiros; Maia, Maria Luiza Bicalho; Júnior, Ronaldo Reis; Fagundes, Marcilio

2016-06-01

Plants have limited resources to invest in reproduction, vegetative growth and defense against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. In this study, we evaluated the trade-off effect between years of high and low fruiting on the investment of resources for growth and defense, and their indirect effects on herbivory in Copaifera langsdorffii. Our questions were: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by the Carbon/Nutrient Balance hypothesis (CNBH), resulting in more availability of resources to be allocated for defense?, (ii) does the variation in resource allocation for growth and defense between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a Cerrado area were monitored during 2008 (year of high fruiting) and 2009 (year of no fruiting) to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defense (tannin concentration and plant hypersensitivity) and herbivory (galling attack and folivory). According to our first question, we observed that in the fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources that could be invested both in growth as in defense. In the same way, we observed an inter-annual variation in herbivorous attack, and found that plants with higher leaf biomass and tannin concentration, experienced higher galling attack and hypersensitive reaction, regardless years. These findings suggested that plants’ resistance to herbivory is a good proxy of plant defense and an effective defense strategy for C. langsdorffii, besides the evidence of indirect responses of the third trophic level, as postulated by the second question. In summary, the supra-annual fruiting pattern promoted several changes on plant development, demonstrating the importance of evaluating different plant traits when characterizing the vegetative investment. As expected by theory, the trade-off in resource allocation favored changes in defense compounds production and patterns of herbivory. The understanding of this important element of insect-plant interactions will be fundamental to decipher coevolutionary life histories and interactions between plant species reproduction and herbivory. Besides that, only through long-term studies we will be able to build models and develop more accurate forecasts about the factors that trigger the bottom-up effect on herbivory performance, as well the top-down effect of herbivores on plant trait evolution.

Children’s Recognition of Fairness and Others’ Welfare in a Resource Allocation Task: Age Related Changes

PubMed Central

Rizzo, Michael T.; Elenbaas, Laura; Cooley, Shelby; Killen, Melanie

2016-01-01

The present study investigated age-related changes regarding children’s (N = 136) conceptions of fairness and others’ welfare in a merit-based resource allocation paradigm. To test whether children at 3- to 5-years-old and 6- to 8-years-old took others’ welfare into account when dividing resources, in addition to merit and equality concerns, children were asked to allocate, judge, and reason about allocations of necessary (needed to avoid harm) and luxury (enjoyable to have) resources to a hardworking and a lazy character. While 3- to 5-year-olds did not differentiate between distributing luxury and necessary resources, 6- to 8-year-olds allocated luxury resources more meritoriously than necessary resources. Further, children based their allocations of necessary resources on concerns for others’ welfare, rather than merit, even when one character was described as working harder. The findings revealed that, with age, children incorporated the concerns for others’ welfare and merit into their conceptions of fairness in a resource allocation context, and prioritized these concerns differently depending on whether they were allocating luxury or necessary resources. Further, with age, children weighed multiple moral concerns including equality, merit, and others’ welfare, when determining the fair allocation of resources. PMID:27455189

Differential gene expression is not required for facultative sex allocation: a transcriptome analysis of brain tissue in the parasitoid wasp Nasonia vitripennis

PubMed Central

Boulton, Rebecca A.; Green, Jade; Trivedi, Urmi; Pannebakker, Bart A.; Ritchie, Michael G.; Shuker, David M.

2018-01-01

Whole-transcriptome technologies have been widely used in behavioural genetics to identify genes associated with the performance of a behaviour and provide clues to its mechanistic basis. Here, we consider the genetic basis of sex allocation behaviour in the parasitoid wasp Nasonia vitripennis. Female Nasonia facultatively vary their offspring sex ratio in line with Hamilton's theory of local mate competition (LMC). A single female or ‘foundress’ laying eggs on a patch will lay just enough sons to fertilize her daughters. As the number of ‘foundresses’ laying eggs on a patch increases (and LMC declines), females produce increasingly male-biased sex ratios. Phenotypic studies have revealed the cues females use to estimate the level of LMC their sons will experience, but our understanding of the genetics underlying sex allocation is limited. Here, we exposed females to three foundress number conditions, i.e. three LMC conditions, and allowed them to oviposit. mRNA was extracted from only the heads of these females to target the brain tissue. The subsequent RNA-seq experiment confirmed that differential gene expression is not associated with the response to sex allocation cues and that we must instead turn to the underlying neuroscience to reveal the underpinnings of this impressive behavioural plasticity. PMID:29515880

Age Differences in Learning from Text: The Effects of Content Preexposure on Reading

ERIC Educational Resources Information Center

Noh, Soo Rim; Shake, Matthew C.; Parisi, Jeanine M.; Joncich, Adam D.; Morrow, Daniel G.; Stine-Morrow, Elizabeth A. L.

2007-01-01

This study investigated age differences in the way in which attentional resources are allocated to expository text and whether these differences are moderated by content preexposure. The organization of the preexposure materials was manipulated to test the hypothesis that a change in organization across two presentations would evoke more…

The Impact of Education on Health Knowledge. NBER Working Paper No. 16422

ERIC Educational Resources Information Center

Altindag, Duha Tore; Cannonier, Colin; Mocan, Naci H.

2010-01-01

The theory on the demand for health suggests that schooling causes health because schooling increases the efficiency of health production. Alternatively, the allocative efficiency hypothesis argues that schooling alters the input mix chosen to produce health. This suggests that the more educated have more knowledge about the health production…

The Misconceptions of Abuse by School Personnel: A Public School Perspective

ERIC Educational Resources Information Center

Starling, Kathleen

2011-01-01

The purpose of this study was to determine the effectiveness of school personnel's perceptions, their need to examine their sexual abuse polices procedures, provide appropriate training to allocate those policies and procedures to all stakeholders in their educational school setting. A mixed methods study was used to explore the hypothesis and…

Napping Reduces Emotional Attention Bias during Early Childhood

ERIC Educational Resources Information Center

Cremone, Amanda; Kurdziel, Laura B. F.; Fraticelli-Torres, Ada; McDermott, Jennifer M.; Spencer, Rebecca M. C.

2017-01-01

Sleep loss alters processing of emotional stimuli in preschool-aged children. However, the mechanism by which sleep modifies emotional processing in early childhood is unknown. We tested the hypothesis that a nap, compared to an equivalent time spent awake, reduces biases in attention allocation to affective information. Children (n = 43;…

Are State legislatures responding to public opinion when allocating funds for tobacco control programs?

PubMed

Snyder, Angela; Falba, Tracy; Busch, Susan; Sindelar, Jody

2004-07-01

This study explored the factors associated with state-level allocations to tobacco-control programs. The primary research question was whether public sentiment regarding tobacco control was a significant factor in the states' 2001 budget decisions. In addition to public opinion, several additional political and economic measures were considered. Significant associations were found between our outcome, state-level tobacco-control funding per capita, and key variables of interest including public opinion, amount of tobacco settlement received, the party affiliation of the governor, the state's smoking rate, excise tax revenue received, and whether the state was a major producer of tobacco. The findings from this study supported our hypothesis that states with citizens who favor more restrictive indoor air policies allocate more to tobacco control. Effective public education to change public opinion and the cultural norms surrounding smoking may affect political decisions and, in turn, increase funding for crucial public health programs.

Adult age differences in the storage of information in working memory.

PubMed

Foos, P W; Wright, L

1992-01-01

The performance of 97 young and 91 old persons were compared to determine if a deficiency in working memory resources for processing, storage, or allocation could be detected. Persons simultaneously performed a storage and one of two processing tasks while instructed to allocate resources to processing, storage, or both tasks. The storage task involved remembering the names of one, three, or five persons. Processing tasks involved solving addition problems presented on flashcards or answering common knowledge questions. Results showed increased age differences on the storage task as demands for resources increased but no differences on processing tasks. Individuals seemed unable to allocate resources as instructed. A comparison of young-old and old-old groups showed the same results as those obtained comparing young and old groups and support the hypothesis of a deficiency of storage, but not processing, resources in working memory for old, especially old-old, adults.

Testing hypotheses for excess flower production and low fruit-to-flower ratios in a pollinating seed-consuming mutualism

USGS Publications Warehouse

Holland, J. Nathaniel; Bronstein, Judith L.; DeAngelis, Donald L.

2004-01-01

Pollinator attraction, pollen limitation, resource limitation, pollen donation and selective fruit abortion have all been proposed as processes explaining why hermaphroditic plants commonly produce many more flowers than mature fruit. We conducted a series of experiments in Arizona to investigate low fruit-to-flower ratios in senita cacti, which rely exclusively on pollinating seed-consumers. Selective abortion of fruit based on seed predators is of particular interest in this case because plants relying on pollinating seed-consumers are predicted to have such a mechanism to minimize seed loss. Pollinator attraction and pollen dispersal increased with flower number, but fruit set did not, refuting the hypothesis that excess flowers increase fruit set by attracting more pollinators. Fruit set of natural- and hand-pollinated flowers were not different, supporting the resource, rather than pollen, limitation hypothesis. Senita did abort fruit, but not selectively based on pollen quantity, pollen donors, or seed predators. Collectively, these results are consistent with sex allocation theory in that resource allocation to excess flower production can increase pollen dispersal and the male fitness function of flowers, but consequently results in reduced resources available for fruit set. Inconsistent with sex allocation theory, however, fruit production and the female fitness function of flowers may actually increase with flower production. This is because excess flower production lowers pollinator-to-flower ratios and results in fruit abortion, both of which limit the abundance and hence oviposition rates, of pre-dispersal seed predators.

Feeding Low or Pharmacological Concentrations of Zinc Oxide Changes the Hepatic Proteome Profiles in Weaned Piglets

PubMed Central

Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

2013-01-01

Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs. PMID:24282572

Sex allocation promotes the stable co-occurrence of competitive species

NASA Astrophysics Data System (ADS)

Kobayashi, Kazuya

2017-03-01

Biodiversity has long been a source of wonder and scientific curiosity. Theoretically, the co-occurrence of competitive species requires niche differentiation, and such differences are well known; however, the neutral theory, which assumes the equivalence of all individuals regardless of the species in a biological community, has successfully recreated observed patterns of biodiversity. In this research, the evolution of sex allocation is demonstrated to be the key to resolving why the neutral theory works well, despite the observed species differences. The sex allocation theory predicts that female-biased allocation evolves in species in declining density and that this allocation improves population growth, which should lead to an increase in density. In contrast, when the density increases, a less biased allocation evolves, which reduces the population growth rate and leads to decreased density. Thus, sex allocation provides a buffer against species differences in population growth. A model incorporating this mechanism demonstrates that hundreds of species can co-occur over 10,000 generations, even in homogeneous environments, and reproduces the observed patterns of biodiversity. This study reveals the importance of evolutionary processes within species for the sustainability of biodiversity. Integrating the entire biological process, from genes to community, will open a new era of ecology.

Evolutionary consequence of a change in life cycle complexity: A link between precocious development and evolution toward female-biased sex allocation in a hermaphroditic parasite.

PubMed

Kasl, Emily L; McAllister, Chris T; Robison, Henry W; Connior, Matthew B; Font, William F; Criscione, Charles D

2015-12-01

The evolutionary consequences of changes in the complex life cycles of parasites are not limited to the traits that directly affect transmission. For instance, mating systems that are altered due to precocious sexual maturation in what is typically regarded as an intermediate host may impact opportunities for outcrossing. In turn, reproductive traits may evolve to optimize sex allocation. Here, we test the hypothesis that sex allocation evolved toward a more female-biased function in populations of the hermaphroditic digenean trematode Alloglossidium progeneticum that can precociously reproduce in their second hosts. In these precocious populations, parasites are forced to self-fertilize as they remain encysted in their second hosts. In contrast, parasites in obligate three-host populations have more opportunities to outcross in their third host. We found strong support that in populations with precocious development, allocation to male resources was greatly reduced. We also identified a potential phenotypically plastic response in a body size sex allocation relationship that may be driven by the competition for mates. These results emphasize how changes in life cycle patterns that alter mating systems can impact the evolution of reproductive traits in parasites. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Optimal allocation of leaf epidermal area for gas exchange.

PubMed

de Boer, Hugo J; Price, Charles A; Wagner-Cremer, Friederike; Dekker, Stefan C; Franks, Peter J; Veneklaas, Erik J

2016-06-01

A long-standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of diffusion and geometry based on the hypothesis that selection for higher anatomical maximum stomatal conductance (gsmax ) involves a trade-off to minimize the fraction of the epidermis that is allocated to stomata. Predicted allometric relationships between stomatal traits were tested with a comprehensive compilation of published and unpublished data on 1057 species from all major clades. In support of our theoretical framework, stomatal traits of this phylogenetically diverse sample reflect spatially optimal allometry that minimizes investment in the allocation of epidermal area when plants evolve towards higher gsmax . Our results specifically highlight that the stomatal morphology of angiosperms evolved along spatially optimal allometric relationships. We propose that the resulting wide range of viable stomatal trait combinations equips angiosperms with developmental and evolutionary flexibility in leaf gas exchange unrivalled by gymnosperms and pteridophytes. © 2016 The Authors New Phytologist © 2016 New Phytologist Trust.

Perceived moral traits of others differentiate the neural activation that underlies inequity-aversion

PubMed Central

Nakatani, Hironori; Ogawa, Akitoshi; Suzuki, Chisato; Asamizuya, Takeshi; Ueno, Kenichi; Cheng, Kang; Okanoya, Kazuo

2017-01-01

We have a social preference to reduce inequity in the outcomes between oneself and others. Such a preference varies according to others. We performed functional magnetic resonance imaging during an economic game to investigate how the perceived moral traits of others modulate the neural activities that underlie inequity-aversion. The participants unilaterally allocated money to three partners (good, neutral, and bad). During presentation of the good and neutral partners, the anterior region of the rostral medial frontal cortex (arMFC) showed increased functional connectivity with the caudate head and the anterior insula, respectively. Following this, participants allocated more money to the good partner, and less to the bad partner, compared with the neutral partner. The caudate head and anterior insula showed greater activation during fair allocation to the good and unfair allocation to the neutral partners, respectively. However, these regions were silent during allocations to the bad partner. Therefore, the arMFC-caudate/insula circuit encompasses distinct neural processes that underlie inequity-aversion in monetary allocations that the different moral traits of others can modulate. PMID:28230155

The regulation of health care providers' payments when horizontal and vertical differentiation matter.

PubMed

Bardey, David; Canta, Chiara; Lozachmeur, Jean-Marie

2012-09-01

This paper analyzes the regulation of payment schemes for health care providers competing in both quality and product differentiation of their services. The regulator uses two instruments: a prospective payment per patient and a cost reimbursement rate. When the regulator can only use a prospective payment, the optimal price involves a trade-off between the level of quality provision and the level of horizontal differentiation. If this pure prospective payment leads to underprovision of quality and overdifferentiation, a mixed reimbursement scheme allows the regulator to improve the allocation efficiency. This is true for a relatively low level of patients' transportation costs. We also show that if the regulator cannot commit to the level of the cost reimbursement rate, the resulting allocation can dominate the one with full commitment. This occurs when the transportation cost is low or high enough, and the full commitment solution either implies full or zero cost reimbursement. Copyright © 2012 Elsevier B.V. All rights reserved.

Bayesian dose selection design for a binary outcome using restricted response adaptive randomization.

PubMed

Meinzer, Caitlyn; Martin, Renee; Suarez, Jose I

2017-09-08

In phase II trials, the most efficacious dose is usually not known. Moreover, given limited resources, it is difficult to robustly identify a dose while also testing for a signal of efficacy that would support a phase III trial. Recent designs have sought to be more efficient by exploring multiple doses through the use of adaptive strategies. However, the added flexibility may potentially increase the risk of making incorrect assumptions and reduce the total amount of information available across the dose range as a function of imbalanced sample size. To balance these challenges, a novel placebo-controlled design is presented in which a restricted Bayesian response adaptive randomization (RAR) is used to allocate a majority of subjects to the optimal dose of active drug, defined as the dose with the lowest probability of poor outcome. However, the allocation between subjects who receive active drug or placebo is held constant to retain the maximum possible power for a hypothesis test of overall efficacy comparing the optimal dose to placebo. The design properties and optimization of the design are presented in the context of a phase II trial for subarachnoid hemorrhage. For a fixed total sample size, a trade-off exists between the ability to select the optimal dose and the probability of rejecting the null hypothesis. This relationship is modified by the allocation ratio between active and control subjects, the choice of RAR algorithm, and the number of subjects allocated to an initial fixed allocation period. While a responsive RAR algorithm improves the ability to select the correct dose, there is an increased risk of assigning more subjects to a worse arm as a function of ephemeral trends in the data. A subarachnoid treatment trial is used to illustrate how this design can be customized for specific objectives and available data. Bayesian adaptive designs are a flexible approach to addressing multiple questions surrounding the optimal dose for treatment efficacy within the context of limited resources. While the design is general enough to apply to many situations, future work is needed to address interim analyses and the incorporation of models for dose response.

Hypotheses to explain the origin of species in Amazonia.

PubMed

Haffer, J

2008-11-01

The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global climatic-vegetational changes affected the biomes of the world not only during the Pleistocene but also during the Tertiary and earlier geological periods. New geoscientific evidence for the effect of dry climatic periods in Amazonia supports the predictions of the Refuge hypothesis. The disturbance-vicariance hypothesis refers to the presumed effect of cold/warm climatic phases of the Pleistocene only and is of limited general relevance because most extant species originated earlier and probably through paleogeographic changes and the formation of ecological refuges during the Tertiary.

Estimating the Full Cost of Family-Financed Time Inputs to Education.

ERIC Educational Resources Information Center

Levine, Victor

This paper presents a methodology for estimating the full cost of parental time allocated to child-care activities at home. Building upon the human capital hypothesis, a model is developed in which the cost of an hour diverted from labor market activity is seen as consisting of three components: 1) direct wages foregone; 2) investments in…

Seven-Year-Olds Allocate Attention Like Adults Unless Working Memory Is Overloaded

ERIC Educational Resources Information Center

Cowan, Nelson; Morey, Candice C.; AuBuchon, Angela M.; Zwilling, Christopher E.; Gilchrist, Amanda L.

2010-01-01

Previous studies have indicated that visual working memory performance increases with age in childhood, but it is not clear why. One main hypothesis has been that younger children are less efficient in their attention; specifically, they are less able to exclude irrelevant items from working memory to make room for relevant items. We examined this…

Feedback control of growth, differentiation, and morphogenesis of pancreatic endocrine progenitors in an epithelial plexus niche

PubMed Central

Bankaitis, Eric D.; Bechard, Matthew E.; Wright, Christopher V.E.

2015-01-01

In the mammalian pancreas, endocrine cells undergo lineage allocation upon emergence from a bipotent duct/endocrine progenitor pool, which resides in the “trunk epithelium.” Major questions remain regarding how niche environments are organized within this epithelium to coordinate endocrine differentiation with programs of epithelial growth, maturation, and morphogenesis. We used EdU pulse-chase and tissue-reconstruction approaches to analyze how endocrine progenitors and their differentiating progeny are assembled within the trunk as it undergoes remodeling from an irregular plexus of tubules to form the eventual mature, branched ductal arbor. The bulk of endocrine progenitors is maintained in an epithelial “plexus state,” which is a transient intermediate during epithelial maturation within which endocrine cell differentiation is continually robust and surprisingly long-lived. Within the plexus, local feedback effects derived from the differentiating and delaminating endocrine cells nonautonomously regulate the flux of endocrine cell birth as well as proliferative growth of the bipotent cell population using Notch-dependent and Notch-independent influences, respectively. These feedback effects in turn maintain the plexus state to ensure prolonged allocation of endocrine cells late into gestation. These findings begin to define a niche-like environment guiding the genesis of the endocrine pancreas and advance current models for how differentiation is coordinated with the growth and morphogenesis of the developing pancreatic epithelium. PMID:26494792

Distinguishing the Biomass Allocation Variance Resulting from Ontogenetic Drift or Acclimation to Soil Texture

PubMed Central

Xie, Jiangbo; Tang, Lisong; Wang, Zhongyuan; Xu, Guiqing; Li, Yan

2012-01-01

In resource-poor environments, adjustment in plant biomass allocation implies a complex interplay between environmental signals and plant development rather than a delay in plant development alone. To understand how environmental factors influence biomass allocation or the developing phenotype, it is necessary to distinguish the biomass allocations resulting from environmental gradients or ontogenetic drift. Here, we compared the development trajectories of cotton plants (Gossypium herbaceum L.), which were grown in two contrasting soil textures during a 60-d period. Those results distinguished the biomass allocation pattern resulting from ontogenetic drift and the response to soil texture. The soil texture significantly changed the biomass allocation to leaves and roots, but not to stems. Soil texture also significantly changed the development trajectories of leaf and root traits, but did not change the scaling relationship between basal stem diameter and plant height. Results of nested ANOVAs of consecutive plant-size categories in both soil textures showed that soil gradients explained an average of 63.64–70.49% of the variation of biomass allocation to leaves and roots. Ontogenetic drift explained 77.47% of the variation in biomass allocation to stems. The results suggested that the environmental factors governed the biomass allocation to roots and leaves, and ontogenetic drift governed the biomass allocation to stems. The results demonstrated that biomass allocation to metabolically active organs (e.g., roots and leaves) was mainly governed by environmental factors, and that biomass allocation to metabolically non-active organs (e.g., stems) was mainly governed by ontogenetic drift. We concluded that differentiating the causes of development trajectories of plant traits was important to the understanding of plant response to environmental gradients. PMID:22911802

Extreme gender flexibility: using a phylogenetic framework to infer the evolution of variation in sex allocation, phylogeography, and speciation in a genus of bidirectional sex changing fishes(Lythrypnus, Gobiidae).

PubMed

Maxfield, Jessica M; Van Tassell, James L; St Mary, Colette M; Joyeux, Jean-Christophe; Crow, Karen D

2012-09-01

The genus Lythrypnus is a group of marine gobies that exhibit extreme gender flexibility as bidirectional sex changers. The genus consists of 20 described species and several undescribed species that are distributed in the Americas. Five species have been characterized with respect to sex allocation and gonad morphology. The hormonal, morphological, and behavioral aspects of sex change have been studied extensively for one species, L. dalli. These data, however, have not been interpreted in an evolutionary context because a phylogenetic hypothesis has not previously been proposed for the genus Lythrypnus. We propose the first phylogenetic hypothesis for the genus based on molecular data from three mitochondrial genes (12s, ND2, and Cytb), one nuclear gene (Rag1) and one nuclear intron (S7). We also include three previously undescribed Lythrypnus species. Our results support the monophyly of the genus with L. heterochroma, an Atlantic species, as the basal taxon. After the divergence of L. heterochroma, there are two main clades, one comprised of species distributed in the Atlantic, the other comprised of species distributed in the Pacific. These data indicate an Atlantic origin for the genus, followed by divergence after the closure of the Isthmus of Panama. Our data also support the monophyly of three previously described species complexes, the L. rhizophora complex and L. dalli complex in the Pacific, and the L. mowbrayi complex in the Atlantic. We mapped patterns of sex allocation within this genus onto the fully resolved and supported topology, and found that sexual plasticity and gender flexibility is likely a synapomorphy for the genus. Overall our results create a well-supported framework to understand the phylogeography of the genus, and to interpret the evolution of sex allocation in Lythrypnus gobies. Copyright © 2012 Elsevier Inc. All rights reserved.

Exploring the psychological underpinnings of the moral mandate effect: motivated reasoning, group differentiation, or anger?

PubMed

Mullen, Elizabeth; Skitka, Linda J

2006-04-01

When people have strong moral convictions about outcomes, their judgments of both outcome and procedural fairness become driven more by whether outcomes support or oppose their moral mandates than by whether procedures are proper or improper (the moral mandate effect). Two studies tested 3 explanations for the moral mandate effect. In particular, people with moral mandates may (a) have a greater motivation to seek out procedural flaws when outcomes fail to support their moral point of view (the motivated reasoning hypothesis), (b) be influenced by in-group distributive biases as a result of identifying with parties that share rather than oppose their moral point of view (the group differentiation hypothesis), or (c) react with anger when outcomes are inconsistent with their moral point of view, which, in turn, colors perceptions of both outcomes and procedures (the anger hypothesis). Results support the anger hypothesis.

Nutrient allocation strategies of woody plants: an approach from the scaling of nitrogen and phosphorus between twig stems and leaves.

PubMed

Yan, Zhengbing; Li, Peng; Chen, Yahan; Han, Wenxuan; Fang, Jingyun

2016-02-05

Allocation of limited nutrients, such as nitrogen (N) and phosphorus (P), among plant organs reflects the influences of evolutionary and ecological processes on functional traits of plants, and thus is related to functional groups and environmental conditions. In this study, we tested this hypothesis by exploring the stoichiometric scaling of N and P concentrations between twig stems and leaves of 335 woody species from 12 forest sites across eastern China. Scaling exponents of twig stem N (or P) to leaf N (or P) varied among functional groups. With increasing latitude, these scaling exponents significantly decreased from >1 at low latitude to <1 at high latitude across the study area. These results suggested that, as plant nutrient concentration increased, plants at low latitudes showed a faster increase in twig stem nutrient concentration, whereas plants at high latitudes presented a faster increase in leaf nutrient concentration. Such shifts in nutrient allocation strategy from low to high latitudes may be controlled by temperature. Overall, our findings provide a new approach to explore plant nutrient allocation strategies by analysing the stoichiometric scaling of nutrients among organs, which could broaden our understanding of the interactions between plants and their environments.

Refined pipe theory for mechanistic modeling of wood development.

PubMed

Deckmyn, Gaby; Evans, Sam P; Randle, Tim J

2006-06-01

We present a mechanistic model of wood tissue development in response to changes in competition, management and climate. The model is based on a refinement of the pipe theory, where the constant ratio between sapwood and leaf area (pipe theory) is replaced by a ratio between pipe conductivity and leaf area. Simulated pipe conductivity changes with age, stand density and climate in response to changes in allocation or pipe radius, or both. The central equation of the model, which calculates the ratio of carbon (C) allocated to leaves and pipes, can be parameterized to describe the contrasting stem conductivity behavior of different tree species: from constant stem conductivity (functional homeostasis hypothesis) to height-related reduction in stem conductivity with age (hydraulic limitation hypothesis). The model simulates the daily growth of pipes (vessels or tracheids), fibers and parenchyma as well as vessel size and simulates the wood density profile and the earlywood to latewood ratio from these data. Initial runs indicate the model yields realistic seasonal changes in pipe radius (decreasing pipe radius from spring to autumn) and wood density, as well as realistic differences associated with the competitive status of trees (denser wood in suppressed trees).

Limited and time-delayed internal resource allocation generates oscillations and chaos in the dynamics of citrus crops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Xujun, E-mail: yexujun@cc.hirosaki-u.ac.jp; Faculty of Agriculture and Life Sciences, Hirosaki University, Aomori 036-8561; Sakai, Kenshi, E-mail: ken@cc.tuat.ac.jp

Alternate bearing or masting is a yield variability phenomenon in perennial crops. The complex dynamics in this phenomenon have stimulated much ecological research. Motivated by data from an eight-year experiment with forty-eight individual trees, we explored the mechanism inherent to these dynamics in Satsuma mandarin (Citrus unshiu Marc.). By integrating high-resolution imaging technology, we found that the canopy structure and reproduction output of individual citrus crops are mutually dependent on each other. Furthermore, it was revealed that the mature leaves in early season contribute their energy to the fruiting of the current growing season, whereas the younger leaves show amore » delayed contribution to the next growing season. We thus hypothesized that the annual yield variability might be caused by the limited and time-delayed resource allocation in individual plants. A novel lattice model based on this hypothesis demonstrates that this pattern of resource allocation will generate oscillations and chaos in citrus yield.« less

Hospital competition, resource allocation and quality of care

PubMed Central

Mukamel, Dana B; Zwanziger, Jack; Bamezai, Anil

2002-01-01

Background A variety of approaches have been used to contain escalating hospital costs. One approach is intensifying price competition. The increase in price based competition, which changes the incentives hospitals face, coupled with the fact that consumers can more easily evaluate the quality of hotel services compared with the quality of clinical care, may lead hospitals to allocate more resources into hotel rather than clinical services. Methods To test this hypothesis we studied hospitals in California in 1982 and 1989, comparing resource allocations prior to and following selective contracting, a period during which the focus of competition changed from quality to price. We estimated the relationship between clinical outcomes, measured as risk-adjusted-mortality rates, and resources. Results In 1989, higher competition was associated with lower clinical expenditures levels compared with 1982. The trend was stronger for non-profit hospitals. Lower clinical resource use was associated with worse risk adjusted mortality outcomes. Conclusions This study raises concerns that cost reductions may be associated with increased mortality. PMID:12052258

Differential Learning as a Key Training Approach to Improve Creative and Tactical Behavior in Soccer

ERIC Educational Resources Information Center

Santos, Sara; Coutinho, Diogo; Gonçalves, Bruno; Schöllhorn, Wolfgang; Sampaio, Jaime; Leite, Nuno

2018-01-01

Purpose: The aim of this study was to identify the effects of a differential-learning program, embedded in small-sided games, on the creative and tactical behavior of youth soccer players. Forty players from under-13 (U13) and under-15 (U15) were allocated into control and experimental groups and were tested using a randomized pretest to posttest…

Seasonal life history trade-offs in two leafwing butterflies: Delaying reproductive development increases life expectancy.

PubMed

McElderry, Robert M

2016-04-01

Surviving inhospitable periods or seasons may greatly affect fitness. Evidence of this exists in the prevalence of dormant stages in the life cycles of most insects. Here I focused on butterflies with distinct seasonal morphological types (not a genetic polymorphism) in which one morphological type, or form, delays reproduction until favorable conditions return, while the other form develops in an environment that favors direct reproduction. For two butterflies, Anaea aidea and A. andria, I tested the hypothesis that the development of each seasonal form involves a differential allocation of resources to survival at eclosion. I assayed differences in adult longevity among summer and winter forms in either a warm, active environment or a cool, calm environment. Winter form adults lived 40 times longer than summer form but only in calm, cool conditions. The magnitude of this difference provided compelling evidence that the winter form body plan and metabolic strategy (i.e. resource conservatism) favor long term survival. This research suggests that winter form adults maintain lowered metabolic rate, a common feature of diapause, to conserve resources and delay senescence while overwintering. Copyright © 2016 Elsevier Ltd. All rights reserved.

Information, education, and health behaviors: Evidence from the MMR vaccine autism controversy.

PubMed

Chang, Lenisa V

2018-05-02

In the wake of strong, although later refuted, claims of a link between autism and the measles-mumps-rubella (MMR) vaccine, I examine whether fewer parents immunized or delayed vaccinations for their children and if there was a differential response by mother's education level. Using various controls and a differencing strategy that compares in MMR take-up with other vaccines, I find that the MMR-autism controversy led to a decline in the immediate years and that there were negative spillovers onto other vaccines. I also find evidence that more highly educated mothers responded more strongly to the controversy either by not immunizing their children altogether or, to a lesser degree, delaying vaccination. Moreover, the educational gap was greater in states where there was greater media attention devoted to the controversy. This is consistent with the health allocative efficiency hypothesis whereby part of the education gradient in health outcomes is due to more-educated individuals absorbing and responding to health information more quickly. However, unlike in the United Kingdom, where previous studies find that the gap was eliminated after the link was refuted, the evidence for the United States suggests that the educational gap persisted. Copyright © 2018 John Wiley & Sons, Ltd.

An Investigation of Luria's Hypothesis on Prompting in Aphasic Naming Disturbances.

ERIC Educational Resources Information Center

Li, Edith Chin; Canter, Gerald J.

1987-01-01

The study investigated A. R. Luria's hypothesis that aphasic subgroups (Broca's, conduction, Wernicke's, and anomic aphasics) would respond differentially to phonemic prompts. Results, with the exception of the anomic aphasic group, supported Luria's predictions. (Author/DB)

Physiological responses of biomass allocation, root architecture, and invertase activity to copper stress in young seedlings from two populations of Kummerowia stipulacea (maxim.) Makino.

PubMed

Zhang, Luan; Pan, Yuxue; Lv, Wei; Xiong, Zhi-ting

2014-06-01

In the current study, we hypothesize that mine (metallicolous) populations of metallophytes form a trade-off between the roots and shoots when under copper (Cu) stress to adapt themselves to heavy metal contaminated habitats, and thus, differ from normal (non-metallicolous) populations in biomass allocation. To test the hypothesis, two populations of the metallophyte Kummerowia stipulacea, one from an ancient Cu mine (MP) and the other from a non-contaminated site (NMP), were treated with Cu(2+) in hydroponic conditions. The results showed that MP plants had higher root/shoot biomass allocation and more complicated root system architecture compared to those of the NMP plants when under Cu stress. The net photosynthetic capacity was more inhibited in the NMP plants than in the MP plants when under Cu stress. The sugar (sucrose and hexose) contents and acid invertase activities of MP plants were elevated while those in NMP plants were inhibited after Cu treatment. The neutral/alkaline invertase activities and sucrose synthase level showed no significant differences between the two populations when under Cu stress. The results showed that acid invertase played an important role in biomass allocation and that the physiological responses were beneficial for the high root/shoot biomass allocation, which were advantageous during adaptive evolution to Cu-enriched mine soils. Copyright © 2014 Elsevier Inc. All rights reserved.

Grazing Soybean to Increase Voluntary Cow Traffic in a Pasture-based Automatic Milking System

PubMed Central

Clark, C. E. F.; Horadagoda, A.; Kerrisk, K. L.; Scott, V.; Islam, M. R.; Kaur, R.; Garcia, S. C.

2014-01-01

Pasture-based automatic milking systems (AMS) require cow traffic to enable cows to be milked. The interval between milkings can be manipulated by strategically allocating pasture. The current experiment investigated the effect of replacing an allocation of grazed pasture with grazed soybean (Glycine max) with the hypothesis that incorporating soybean would increase voluntary cow traffic and milk production. One hundred and eighty mixed age, primiparous and multiparous Holstein-Friesian/Illawarra cows were randomly assigned to two treatment groups (n = 90/group) with a 2×2 Latin square design. Each group was either offered treatments of kikuyu grass (Pennisetum clandestinum Hoach ex Chiov.) pasture (pasture) or soybean from 0900 h to 1500 h during the experimental period which consisted of 2 periods of 3 days following 5 days of training and adaptation in each period with groups crossing over treatments after the first period. The number of cows trafficking to each treatment was similar together with milk yield (mean ≈18 L/cow/d) in this experiment. For the cows that arrived at soybean or pasture there were significant differences in their behaviour and consequently the number of cows exiting each treatment paddock. There was greater cow traffic (more cows and sooner) exiting pasture allocations. Cows that arrived at soybean stayed on the allocation for 25% more time and ate more forage (8.5 kg/cow/d/allocation) relative to pasture (4.7 kg/cow/d/allocation). Pasture cows predominantly replaced eating time with rumination. These findings suggest that replacing pasture with alternative grazeable forages provides no additional incentive to increase voluntary cow traffic to an allocation of feed in AMS. This work highlights the opportunity to increase forage intakes in AMS through the incorporation of alternative forages. PMID:25049970

The Trivers–Willard hypothesis: sex ratio or investment?

PubMed Central

Veller, Carl; Haig, David; Nowak, Martin A.

2016-01-01

The Trivers–Willard hypothesis has commonly been considered to predict two things. First, that a mother in good condition should bias the sex ratio of her offspring towards males (if males exhibit greater variation in reproductive value). Second, that a mother in good condition should invest more per son than per daughter. These two predictions differ empirically, mechanistically and, as we demonstrate here, theoretically too. We construct a simple model of sex allocation that allows simultaneous analysis of both versions of the Trivers–Willard hypothesis. We show that the sex ratio version holds under very general conditions, being valid for a large class of male and female fitness functions. The investment version, on the other hand, is shown to hold only for a small subset of male and female fitness functions. Our results help to make sense of the observation that the sex ratio version is empirically more successful than the investment version. PMID:27170721

Allocation of recent photoassimilates in mature European beech and Norway spruce - seasonal variability and responses to experimentally increased tropospheric O3 concentration and long-term drought

NASA Astrophysics Data System (ADS)

Grams, Thorsten

2016-04-01

This contribution summarizes a series of C allocation studies in maturing European beech and Norway spruce trees at Kranzberg Forest, located in southern Germany. Study objects are 60 to 70 year old trees, readily accessible via scaffoldings and canopy crane. Allocation of recently fixed photoassimilates is assessed either by conventional branch-bag labelling with 99 atom% 13CO2 or whole-tree labeling using 13C-depleted CO2 (isoFACE system). While labeling in branch bags, employed for few hours only, focused on phloem functionality in particular under long-term drought, C labeling of whole tree canopies was employed for up to 20 days, studying allocation of recent photoassimilates from the canopy along branches and stems to roots and soils below ground. In all experiments, dynamics of C allocation were mostly pursued assessing carbon isotopic composition of CO2 efflux from woody tissues which typically reflected isotopic composition of phloem sugars. Effects of severe and long-term summer drought are assessed in an ongoing experiment with roughly 100 trees assigned to a total of 12 plots (kroof.wzw.tum.de). Precipitation throughfall was completely excluded since early spring, resulting in pre-dawn leaf water potentials of both beech and spruce up to -2.2 MPa. The hypothesis was tested that long-term drought affects allocation of recently fixed C to branches and phloem functionality. In the annual course under unstressed conditions, phloem transport speed from the canopy to the stem (breast height) was double in beech compared to spruce, with highest transport velocities in early summer (about 0.51 and 0.26 m/h) and lowest in spring (0.26 and 0.12 m/h for beech and spruce, respectively). After leaf flush in spring, growth respiration of beech trunks was largely supplied by C stores. Recent photoassimilates supplied beech stem growth in early summer and refilled C stores in late summer, whereas seasonality was less pronounced in spruce. The hypothesis that growth respiration is exclusively supplied by recently fixed C was rejected for both species. After long-term (7 years) exposure to elevated (i.e. twice-ambient) O3 concentrations, allocation of recently fixed C to stems was distinctly affected when studied during later summer. In correspondence with significantly lowered woody biomass development in beech (- 40 %), C allocation to stems was reduced in response to O3 exposure. Conversely in spruce, photoassimilate allocation to stems and coarse root respiration was hardly affected, reflecting the overall lower sensitivity of spruce to elevated O3 concentrations. Compartmental modeling characterized functional properties of substrate pools supplying respiratory C demands. Stem respiration of spruce appeared to be largely supplied by recent photoassimilates. Conversely in beech, stored C, putatively located in stem parenchyma cells, was a major source for respiration, reflecting the fundamental anatomical disparity between angiosperm beech and gymnosperm spruce. Overall, the observed differences in C allocation between the two study species reflect the high plasticity of beech trees in response to seasons and stressors such as drought and elevated O3, whereas spruce displayed much lower responsiveness to the applied stressors and along the seasonal course of the year.

Differentiated protection services with failure probability guarantee for workflow-based applications

NASA Astrophysics Data System (ADS)

Zhong, Yaoquan; Guo, Wei; Jin, Yaohui; Sun, Weiqiang; Hu, Weisheng

2010-12-01

A cost-effective and service-differentiated provisioning strategy is very desirable to service providers so that they can offer users satisfactory services, while optimizing network resource allocation. Providing differentiated protection services to connections for surviving link failure has been extensively studied in recent years. However, the differentiated protection services for workflow-based applications, which consist of many interdependent tasks, have scarcely been studied. This paper investigates the problem of providing differentiated services for workflow-based applications in optical grid. In this paper, we develop three differentiated protection services provisioning strategies which can provide security level guarantee and network-resource optimization for workflow-based applications. The simulation demonstrates that these heuristic algorithms provide protection cost-effectively while satisfying the applications' failure probability requirements.

The Ethnic Niche as an Economic Pathway for the Dark Skinned: Labor Market Incorporation of Latina/o Workers

ERIC Educational Resources Information Center

Morales, Maria Cristina

2008-01-01

A significant number of Latina/os are turning to employment in ethnic niches as an alternative to general labor markets. This study places special focus on how skin color segmentation or colorism influences job-market allocation. The hypothesis is that dark-skinned Latina/os are more likely to be employed in ethnically homogeneous jobsites or…

Allocation to leaf area and sapwood area affects water relations of co-occurring savanna and forest trees

Treesearch

Sybil G. Gotsch; Erika L. Geiger; Augusto C. Franco; Guillermo Goldstein; Frederick C. Meinzer; William A. Hoffmann

2010-01-01

Water availability is a principal factor limiting the distribution of closed-canopy forest in the seasonal tropics, suggesting that forest tree species may not be well adapted to cope with seasonal drought. We studied 11 congeneric species pairs, each containing one forest and one savanna species, to test the hypothesis that forest trees have a lower capacity to...

Mathematical ability and the right-shift theory of handedness.

PubMed

Whittington, J E; Richards, P N

1991-01-01

A genetic theory of handedness, the right-shift theory, associates differential patterns of cerebral functioning with contrasting handedness groups and suggests that individuals with an rs + + genotype will be disadvantaged in mathematical performance. This hypothesis is investigated with contrasting handedness groups drawn from a national sample of over 11,000 children from the National Child Development Study. Some differentiation in cognitive performance between handedness groups is found in the direction predicted by the right-shift theory but the level of the findings is not statistically significant. The rs+ +/mathematical deficit hypothesis is not confirmed.

How to get the most bang for your buck: the evolution and physiology of nutrition-dependent resource allocation strategies.

PubMed

Ng'oma, Enoch; Perinchery, Anna M; King, Elizabeth G

2017-06-28

All organisms use resources to grow, survive and reproduce. The supply of these resources varies widely across landscapes and time, imposing ultimate constraints on the maximal trait values for allocation-related traits. In this review, we address three key questions fundamental to our understanding of the evolution of allocation strategies and their underlying mechanisms. First, we ask: how diverse are flexible resource allocation strategies among different organisms? We find there are many, varied, examples of flexible strategies that depend on nutrition. However, this diversity is often ignored in some of the best-known cases of resource allocation shifts, such as the commonly observed pattern of lifespan extension under nutrient limitation. A greater appreciation of the wide variety of flexible allocation strategies leads directly to our second major question: what conditions select for different plastic allocation strategies? Here, we highlight the need for additional models that explicitly consider the evolution of phenotypically plastic allocation strategies and empirical tests of the predictions of those models in natural populations. Finally, we consider the question: what are the underlying mechanisms determining resource allocation strategies? Although evolutionary biologists assume differential allocation of resources is a major factor limiting trait evolution, few proximate mechanisms are known that specifically support the model. We argue that an integrated framework can reconcile evolutionary models with proximate mechanisms that appear at first glance to be in conflict with these models. Overall, we encourage future studies to: (i) mimic ecological conditions in which those patterns evolve, and (ii) take advantage of the 'omic' opportunities to produce multi-level data and analytical models that effectively integrate across physiological and evolutionary theory. © 2017 The Author(s).

How to get the most bang for your buck: the evolution and physiology of nutrition-dependent resource allocation strategies

PubMed Central

2017-01-01

All organisms use resources to grow, survive and reproduce. The supply of these resources varies widely across landscapes and time, imposing ultimate constraints on the maximal trait values for allocation-related traits. In this review, we address three key questions fundamental to our understanding of the evolution of allocation strategies and their underlying mechanisms. First, we ask: how diverse are flexible resource allocation strategies among different organisms? We find there are many, varied, examples of flexible strategies that depend on nutrition. However, this diversity is often ignored in some of the best-known cases of resource allocation shifts, such as the commonly observed pattern of lifespan extension under nutrient limitation. A greater appreciation of the wide variety of flexible allocation strategies leads directly to our second major question: what conditions select for different plastic allocation strategies? Here, we highlight the need for additional models that explicitly consider the evolution of phenotypically plastic allocation strategies and empirical tests of the predictions of those models in natural populations. Finally, we consider the question: what are the underlying mechanisms determining resource allocation strategies? Although evolutionary biologists assume differential allocation of resources is a major factor limiting trait evolution, few proximate mechanisms are known that specifically support the model. We argue that an integrated framework can reconcile evolutionary models with proximate mechanisms that appear at first glance to be in conflict with these models. Overall, we encourage future studies to: (i) mimic ecological conditions in which those patterns evolve, and (ii) take advantage of the ‘omic’ opportunities to produce multi-level data and analytical models that effectively integrate across physiological and evolutionary theory. PMID:28637856

Global genetic differentiation of complex traits shaped by natural selection in humans.

PubMed

Guo, Jing; Wu, Yang; Zhu, Zhihong; Zheng, Zhili; Trzaskowski, Maciej; Zeng, Jian; Robinson, Matthew R; Visscher, Peter M; Yang, Jian

2018-05-14

There are mean differences in complex traits among global human populations. We hypothesize that part of the phenotypic differentiation is due to natural selection. To address this hypothesis, we assess the differentiation in allele frequencies of trait-associated SNPs among African, Eastern Asian, and European populations for ten complex traits using data of large sample size (up to ~405,000). We show that SNPs associated with height ([Formula: see text]), waist-to-hip ratio ([Formula: see text]), and schizophrenia ([Formula: see text]) are significantly more differentiated among populations than matched "control" SNPs, suggesting that these trait-associated SNPs have undergone natural selection. We further find that SNPs associated with height ([Formula: see text]) and schizophrenia ([Formula: see text]) show significantly higher variance in linkage disequilibrium (LD) scores across populations than control SNPs. Our results support the hypothesis that natural selection has shaped the genetic differentiation of complex traits, such as height and schizophrenia, among worldwide populations.

The ecology of sex explains patterns of helping in arthropod societies.

PubMed

Davies, Nicholas G; Ross, Laura; Gardner, Andy

2016-08-01

Across arthropod societies, sib-rearing (e.g. nursing or nest defence) may be provided by females, by males or by both sexes. According to Hamilton's 'haplodiploidy hypothesis', this diversity reflects the relatedness consequences of diploid vs. haplodiploid inheritance. However, an alternative 'preadaptation hypothesis' instead emphasises an interplay of ecology and the co-option of ancestral, sexually dimorphic traits for sib-rearing. The preadaptation hypothesis has recently received empirical support, but remains to be formalised. Here, we mathematically model the coevolution of sex-specific helping and sex allocation, contrasting these hypotheses. We find that ploidy per se has little effect. Rather, the ecology of sex shapes patterns of helping: sex-specific preadaptation strongly influences who helps; a freely adjustable sex ratio magnifies sex biases and promotes helping; and sib-mating, promiscuity, and reproductive autonomy also modulate the sex and abundance of helpers. An empirical survey reveals that patterns of sex-specific helping in arthropod taxa are consistent with the preadaptation hypothesis. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Systems and Photosystems: Cellular Limits of Autotrophic Productivity in Cyanobacteria

PubMed Central

Burnap, Robert L.

2014-01-01

Recent advances in the modeling of microbial growth and metabolism have shown that growth rate critically depends upon the optimal allocation of finite proteomic resources among different cellular functions and that modeling growth rates becomes more realistic with the explicit accounting for the costs of macromolecular synthesis, most importantly, protein expression. The “proteomic constraint” is considered together with its application to understanding photosynthetic microbial growth. The central hypothesis is that physical limits of cellular space (and corresponding solvation capacity) in conjunction with cell surface-to-volume ratios represent the underlying constraints on the maximal rate of autotrophic microbial growth. The limitation of cellular space thus constrains the size the total complement of macromolecules, dissolved ions, and metabolites. To a first approximation, the upper limit in the cellular amount of the total proteome is bounded this space limit. This predicts that adaptation to osmotic stress will result in lower maximal growth rates due to decreased cellular concentrations of core metabolic proteins necessary for cell growth owing the accumulation of compatible osmolytes, as surmised previously. The finite capacity of membrane and cytoplasmic space also leads to the hypothesis that the species-specific differences in maximal growth rates likely reflect differences in the allocation of space to niche-specific proteins with the corresponding diminution of space devoted to other functions including proteins of core autotrophic metabolism, which drive cell reproduction. An optimization model for autotrophic microbial growth, the autotrophic replicator model, was developed based upon previous work investigating heterotrophic growth. The present model describes autotrophic growth in terms of the allocation protein resources among core functional groups including the photosynthetic electron transport chain, light-harvesting antennae, and the ribosome groups. PMID:25654078

Top-down and bottom-up attention-to-memory: mapping functional connectivity in two distinct networks that underlie cued and uncued recognition memory.

PubMed

Burianová, Hana; Ciaramelli, Elisa; Grady, Cheryl L; Moscovitch, Morris

2012-11-15

The objective of this study was to examine the functional connectivity of brain regions active during cued and uncued recognition memory to test the idea that distinct networks would underlie these memory processes, as predicted by the attention-to-memory (AtoM) hypothesis. The AtoM hypothesis suggests that dorsal parietal cortex (DPC) allocates effortful top-down attention to memory retrieval during cued retrieval, whereas ventral parietal cortex (VPC) mediates spontaneous bottom-up capture of attention by memory during uncued retrieval. To identify networks associated with these two processes, we conducted a functional connectivity analysis of a left DPC and a left VPC region, both identified by a previous analysis of task-related regional activations. We hypothesized that the two parietal regions would be functionally connected with distinct neural networks, reflecting their engagement in the differential mnemonic processes. We found two spatially dissociated networks that overlapped only in the precuneus. During cued trials, DPC was functionally connected with dorsal attention areas, including the superior parietal lobules, right precuneus, and premotor cortex, as well as relevant memory areas, such as the left hippocampus and the middle frontal gyri. During uncued trials, VPC was functionally connected with ventral attention areas, including the supramarginal gyrus, cuneus, and right fusiform gyrus, as well as the parahippocampal gyrus. In addition, activity in the DPC network was associated with faster response times for cued retrieval. This is the first study to show a dissociation of the functional connectivity of posterior parietal regions during episodic memory retrieval, characterized by a top-down AtoM network involving DPC and a bottom-up AtoM network involving VPC. Copyright © 2012 Elsevier Inc. All rights reserved.

Capacity allocation mechanism based on differentiated QoS in 60 GHz radio-over-fiber local access network

NASA Astrophysics Data System (ADS)

Kou, Yanbin; Liu, Siming; Zhang, Weiheng; Shen, Guansheng; Tian, Huiping

2017-03-01

We present a dynamic capacity allocation mechanism based on the Quality of Service (QoS) for different mobile users (MU) in 60 GHz radio-over-fiber (RoF) local access networks. The proposed mechanism is capable for collecting the request information of MUs to build a full list of MU capacity demands and service types at the Central Office (CO). A hybrid algorithm is introduced to implement the capacity allocation which can satisfy the requirements of different MUs at different network traffic loads. Compared with the weight dynamic frames assignment (WDFA) scheme, the Hybrid scheme can keep high priority MUs in low delay and maintain the packet loss rate less than 1% simultaneously. At the same time, low priority MUs have a relatively better performance.

A Simplified GCS-DCSK Modulation and Its Performance Optimization

NASA Astrophysics Data System (ADS)

Xu, Weikai; Wang, Lin; Chi, Chong-Yung

2016-12-01

In this paper, a simplified Generalized Code-Shifted Differential Chaos Shift Keying (GCS-DCSK) whose transmitter never needs any delay circuits, is proposed. However, its performance is deteriorated because the orthogonality between substreams cannot be guaranteed. In order to optimize its performance, the system model of the proposed GCS-DCSK with power allocations on substreams is presented. An approximate bit error rate (BER) expression of the proposed model, which is a function of substreams’ power, is derived using Gaussian Approximation. Based on the BER expression, an optimal power allocation strategy between information substreams and reference substream is obtained. Simulation results show that the BER performance of the proposed GCS-DCSK with the optimal power allocation can be significantly improved when the number of substreams M is large.

Effects of generalist herbivory on resistance and resource allocation by the invasive plant, Phytolacca americana.

PubMed

Huang, Wei; Ding, Jianqing

2016-04-01

Successful invasions by exotic plants are often attributed to a loss of co-evolved specialists and a re-allocation of resources from defense to growth and reproduction. However, invasive plants are rarely completely released from insect herbivory because they are frequently attacked by generalists in their introduced ranges. The novel generalist community may also affect the invasive plant's defensive strategies and resource allocation. Here, we tested this hypothesis using American pokeweed (Phytolacca americana L.), a species that has become invasive in China, which is native to North America. We examined resistance, tolerance, growth and reproduction of plant populations from both China and the USA when plants were exposed to natural generalist herbivores in China. We found that leaf damage was greater for invasive populations than for native populations, indicating that plants from invasive ranges had lower resistance to herbivory than those from native ranges. A regression of the percentage of leaf damage against mass showed that there was no significant difference in tolerance between invasive and native populations, even though the shoot, root, fruit and total mass were larger for invasive populations than for native populations. These results suggest that generalist herbivores are important drivers mediating the defensive strategies and resource allocation of the invasive American pokeweed. © 2015 Institute of Zoology, Chinese Academy of Sciences.

The gender gap in student engagement: The role of teachers' autonomy support, structure, and involvement.

PubMed

Lietaert, Sofie; Roorda, Debora; Laevers, Ferre; Verschueren, Karine; De Fraine, Bieke

2015-12-01

The gender gap in education in favour of girls is a widely known phenomenon. Boys generally have higher dropout rates, obtain lower grades, and show lower engagement. Insight into factors related to these academic outcomes could help to address the gender gap. This study investigated, for Dutch language classes, (1) how boys and girls differ in behavioural engagement, (2) which teacher support dimensions (autonomy support, structure, involvement) may explain gender differences in engagement (mediation hypothesis), and (3) whether and which of these teacher support dimensions matter more for boys' as opposed to girls' engagement (moderation or differential effects hypothesis). A total of 385 Grade 7 students and their 15 language teachers participated in this study. Teacher support was assessed through student reports. Student engagement was measured using student, teacher, and observer reports. By means of structural equation modelling, the mediating role of the teacher support dimensions for gender differences in behavioural engagement was tested. The potential differential role of the teacher support dimensions for boys' and girls' engagement was investigated through multigroup analysis. Boys were less engaged than girls and reported lower support from their teacher. Autonomy support and involvement partially mediated the relationship between gender and behavioural engagement. Autonomy support was demonstrated to be a protective factor for boys' engagement but not for girls'. Structure and involvement contributed equally to engagement for both sexes. Although involvement and autonomy support partly explained the gender gap in engagement (mediation hypothesis), more support was found for differential effects of autonomy support on boys' versus girls' engagement (differential effects hypothesis). © 2015 The British Psychological Society.

Public hospital resource allocations in El Salvador: accounting for the case mix of patients.

PubMed

Fiedler, J L; Schmidt, R M; Wight, J B

1998-09-01

National hospitals in developing countries command a disproportionate share of medical care budgets, justified on the grounds that they have a more difficult patient case mix and higher occupancy rates than decentralized district hospitals or clinics. This paper empirically tests the hypothesis by developing direct measures of the severity of patient illness, hospital case-mix and a resource intensity index for each of El Salvador's public hospitals. Based on an analysis of inpatient care staffing requirements, national hospitals are found to receive funding far in excess of what case-mix and case-load considerations would warrant. The findings suggest that significant system-wide efficiency gains can be realized by allocating hospital budgets on the bases of performance-related criteria which incorporate the case-mix approach developed here.

Short-term storage allocation in a filmless hospital

NASA Astrophysics Data System (ADS)

Strickland, Nicola H.; Deshaies, Marc J.; Reynolds, R. Anthony; Turner, Jonathan E.; Allison, David J.

1997-05-01

Optimizing limited short term storage (STS) resources requires gradual, systematic changes, monitored and modified within an operational PACS environment. Optimization of the centralized storage requires a balance of exam numbers and types in STS to minimize lengthy retrievals from long term archive. Changes to STS parameters and work procedures were made while monitoring the effects on resource allocation by analyzing disk space temporally. Proportions of disk space allocated to each patient category on STS were measured to approach the desired proportions in a controlled manner. Key factors for STS management were: (1) sophisticated exam prefetching algorithms: HIS/RIS-triggered, body part-related and historically-selected, and (2) a 'storage onion' design allocating various exam categories to layers with differential deletion protection. Hospitals planning for STS space should consider the needs of radiology, wards, outpatient clinics and clinicoradiological conferences for new and historical exams; desired on-line time; and potential increase in image throughput and changing resources, such as an increase in short term storage disk space.

Waste management: how reducing partiality can promote efficient resource allocation.

PubMed

Choshen-Hillel, Shoham; Shaw, Alex; Caruso, Eugene M

2015-08-01

Two central principles that guide resource-allocation decisions are equity (providing equal pay for equal work) and efficiency (not wasting resources). When these two principles conflict with one another, people will often waste resources to avoid inequity. We suggest that people wish to avoid inequity not because they find it inherently unfair, but because they want to avoid the appearance of partiality associated with it. We explore one way to reduce waste by reducing the perceived partiality of inequitable allocations. Specifically, we hypothesize that people will be more likely to favor an efficient (albeit inequitable) allocation if it puts them in a disadvantaged position than if it puts others in a disadvantaged position. To test this hypothesis, we asked participants to choose between giving some extra resource to one person (thereby creating inequity between this person and equally deserving others) and not giving the resource to anyone (thereby wasting the resource). Six studies, using realistic scenarios and behavioral paradigms, provide robust evidence for a self-disadvantaging effect: Allocators were consistently more likely to create inequity to avoid wasting resources when the resulting inequity would put them at a relative disadvantage than when it would put others at a relative disadvantage. We further find that this self-disadvantaging effect is a direct result of people's concern about appearing partial. Our findings suggest the importance of impartiality even in distributive justice, thereby bridging a gap between the distributive and procedural justice literatures. (c) 2015 APA, all rights reserved.

Dialysis in rats with acute renal failure: evaluation of three different dialyzer membranes.

PubMed

Kränzlin, B; Gretz, N; Kirschfink, M; Mujais, S K

1996-11-01

Exposure to complement-activating cellulosic dialysis membranes has been claimed to adversely affect the course of acute renal failure (ARF). To test this hypothesis, male Sprague-Dawley rats were allocated to 2 groups: in Group 1, ARF was induced by bilateral renal artery clamping whereas in Group 2, animals underwent a sham procedure. In each group, rats were further allocated to undergo hemodialysis with either a Cuprophan, a Hemophan, or a polyacrylonitrile minidialyzer on Days 4 and 8 after surgery, or no dialysis. Renal function was measured by inulin clearance on the days after dialysis. Additionally, total complement activity (CH50) was estimated on Days 1, 2, 4, and 8, and complement factor C3 was detected immunohistochemically. The degree of renal failure and the rate of recovery of renal function were similar in all the ARF groups irrespective of whether they had undergone dialysis or not, or of the type of the dialysis membrane. Furthermore, there were no significant differences in the course of CH50 or in the amount and distribution of complement factor C3 in the kidney tissue between the rats of Groups 1 and 2. Our findings refute the hypothesis that in ischemic ARF exposure to complement-activating cellulosic dialysis membranes impairs the recovery of renal function in rats.

The effect of dietary nicotine on the allocation of assimilated food to energy metabolism and growth in fourth-instar larvae of the southern armyworm, Spodoptera eridania (Lepidoptera: Noctuidae).

PubMed

Cresswell, James E; Merritt, Stewart Z; Martin, Michael M

1992-03-01

Dietary nicotine (0.5%), which is a substrate of the PSMO (polysubstrate monooxygenase) detoxification system in the southern armyworm Spodoptera eridania, has significant negative effects on the weight of food ingested, weight gained, relative growth rate (RGR), and efficiency of conversion of digested food (ECD) by fourthinstar S. eridania larvae on a nutrient-rich artificial diet. It has a significant positive effect on the weight of food respired by the larvae. Thus, the detoxification of nicotine by the PSMO system exacts a fitness cost and imposes a metabolic cost on S. eridania larvae. In contrast, dietary α-(+)-pinene, an inducer of the PSMO system, neither exacts a fitness cost nor imposes a metabolic cost on the larvae. We believe this to be the first study to demonstrate unequivocally that the negative effect of a dietary toxin on net growth efficiency (ECD) in an insect herbivore is due to an increase in the allocation of assimilated food to energy metabolism and not to a decrease in the amount of food assimilated. This study, therefore, supports the hypothesis that detoxification can impose a significant metabolic load on an insect herbivore. Implications of a corroboration of the metabolic load hypothesis are discussed.

Emotional Development across Adulthood: Differential Age-Related Emotional Reactivity and Emotion Regulation in a Negative Mood Induction Procedure

ERIC Educational Resources Information Center

Kliegel, Matthias; Jager, Theodor; Phillips, Louise H.

2007-01-01

The present study examines the hypothesis that older adults might differentially react to a negative versus neutral mood induction procedure than younger adults. The rationale for this expectation was derived from Socioemotional Selectivity Theory (SST), which postulates differential salience of emotional information and ability to regulate…

Growth-differentiation balance: a basis for understanding southern pine beetle - tree interactions

Treesearch

Peter L. Lorio

1986-01-01

Interrelationships between the southern pine beetle (SPB), Dendroctonus frontalis Zimm.) and its host pines are explained in terms of the growth-differentiation balance concept.A general hypothesis is proposed based on growth-differentiation balance in southern pines (radial growth of stems versus synthesis and yield of oleoresin) and seasonal activity of the SPB based...

Probabilistic objective functions for sensor management

NASA Astrophysics Data System (ADS)

Mahler, Ronald P. S.; Zajic, Tim R.

2004-08-01

This paper continues the investigation of a foundational and yet potentially practical basis for control-theoretic sensor management, using a comprehensive, intuitive, system-level Bayesian paradigm based on finite-set statistics (FISST). In this paper we report our most recent progress, focusing on multistep look-ahead -- i.e., allocation of sensor resources throughout an entire future time-window. We determine future sensor states in the time-window using a "probabilistically natural" sensor management objective function, the posterior expected number of targets (PENT). This objective function is constructed using a new "maxi-PIMS" optimization strategy that hedges against unknowable future observation-collections. PENT is used in conjuction with approximate multitarget filters: the probability hypothesis density (PHD) filter or the multi-hypothesis correlator (MHC) filter.

Plasticity in seedling morphology, biomass allocation and physiology among ten temperate tree species in response to shade is related to shade tolerance and not leaf habit.

PubMed

Chmura, D J; Modrzyński, J; Chmielarz, P; Tjoelker, M G

2017-03-01

Mechanisms of shade tolerance in tree seedlings, and thus growth in shade, may differ by leaf habit and vary with ontogeny following seed germination. To examine early responses of seedlings to shade in relation to morphological, physiological and biomass allocation traits, we compared seedlings of 10 temperate species, varying in their leaf habit (broadleaved versus needle-leaved) and observed tolerance to shade, when growing in two contrasting light treatments - open (about 20% of full sunlight) and shade (about 5% of full sunlight). We analyzed biomass allocation and its response to shade using allometric relationships. We also measured leaf gas exchange rates and leaf N in the two light treatments. Compared to the open treatment, shading significantly increased traits typically associated with high relative growth rate (RGR) - leaf area ratio (LAR), specific leaf area (SLA), and allocation of biomass into leaves, and reduced seedling mass and allocation to roots, and net assimilation rate (NAR). Interestingly, RGR was not affected by light treatment, likely because of morphological and physiological adjustments in shaded plants that offset reductions of in situ net assimilation of carbon in shade. Leaf area-based rates of light-saturated leaf gas exchange differed among species groups, but not between light treatments, as leaf N concentration increased in concert with increased SLA in shade. We found little evidence to support the hypothesis of a increased plasticity of broadleaved species compared to needle-leaved conifers in response to shade. However, an expectation of higher plasticity in shade-intolerant species than in shade-tolerant ones, and in leaf and plant morphology than in biomass allocation was supported across species of contrasting leaf habit. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Differentiating between rights-based and relational ethical approaches.

PubMed

Trobec, Irena; Herbst, Majda; Zvanut, Bostjan

2009-05-01

When forced treatment in mental health care is under consideration, two approaches guide clinicians in their actions: the dominant rights-based approach and the relational ethical approach. We hypothesized that nurses with bachelor's degrees differentiate better between the two approaches than nurses without a degree. To test this hypothesis a survey was performed in major Slovenian health institutions. We found that nurses emphasize the importance of ethics and personal values, but 55.4% of all the nurse participants confused the two approaches. The results confirmed our hypothesis and indicate the importance of nurses' formal education, especially when caring for patients with mental illness.

BIOLOGIC EFFECTS OF INHALED DIESEL EXHAUST IN YOUNG AND OLD MICE: A PILOT PROJECT

EPA Science Inventory

The investigators hypothesis is that TNF-a production will be shown to be impaired in old animals exposed to diesel exhaust. The investigators extend  their hypothesis to suggest that exposure to diesel exhaust may differentially affect molecules involved in i...

Hypothesis Sampling Systems among Preoperational and Concrete Operational Kindergarten Children

ERIC Educational Resources Information Center

Gholson, Barry; And Others

1976-01-01

Preoperational and concrete operational kindergarten children received stimulus differentiation training, either with or without feedback, and then a series of discrimination learning problems in which a blank trial probe was used to detect a child's hypothesis after each feedback trial. Piagetian stage theory requires elaboration to account…

Isolating Exogenous and Endogenous Modes of Temporal Attention

ERIC Educational Resources Information Center

Lawrence, Michael A.; Klein, Raymond M.

2013-01-01

The differential allocation of information processing resources over time, here termed "temporal attention," may be achieved by relatively automatic "exogenous" or controlled "endogenous" mechanisms. Over 100 years of research has confounded these theoretically distinct dimensions of temporal attention. The current…

The Effect of IV Amino Acid Supplementation on Mortality in ICU Patients May Be Dependent on Kidney Function: Post Hoc Subgroup Analyses of a Multicenter Randomized Trial.

PubMed

Zhu, Ran; Allingstrup, Matilde J; Perner, Anders; Doig, Gordon S

2018-05-15

We investigated whether preexisting kidney function determines if ICU patients may benefit from increased (2.0 g/kg/d) protein intake. Post hoc, hypothesis-generating, subgroup analysis of a multicenter, phase 2, randomized clinical trial. All analyses were conducted by intention to treat and maintained group allocation. Ninety-day mortality was the primary outcome. ICUs of 16 hospitals throughout Australia and New Zealand. Adult critically ill patients expected to remain in the study ICU for longer than 2 days. Random allocation to receive a daily supplement of up to 100 g of IV amino acids to achieve a total protein intake of 2.0 g/kg/d or standard nutrition care. A total of 474 patients were randomized: 235 to standard care and 239 to IV amino acid supplementation. There was a statistically significant interaction between baseline kidney function and supplementation with study amino acids (p value for interaction = 0.026). Within the subgroup of patients with normal kidney function at randomization, patients who were allocated to receive the study amino acid supplement were less likely to die before study day 90 (covariate-adjusted risk difference, -7.9%; 95% CI, -15.1 to -0.7; p = 0.034). Furthermore, amino acid supplementation significantly increased estimated glomerular filtration rate in these patients (repeated-measures treatment × time interaction p = 0.009). Within the subgroup of patients with baseline kidney dysfunction and/or risk of progression of acute kidney injury, a significant effect of the study intervention on mortality was not found (covariate-adjusted risk difference, -0.6%; 95% CI, -16.2 to 15.2; p = 0.95). In this post hoc, hypothesis-generating, subgroup analysis, we observed reduced mortality and improved estimated glomerular filtration rate in ICU patients with normal kidney function who were randomly allocated to receive increased protein intake (up to 2.0 g/kg/d). We strongly recommend confirmation of these results in trials with low risk of bias before this treatment is recommended for routine care.

Comparing long-term geomorphic model outcomes with sediment archives highlights the need for high-resolution Holocene land cover reconstructions

NASA Astrophysics Data System (ADS)

De Brue, Hanne; Verstraeten, Gert

2013-04-01

During the last decade, several global land cover reconstructions have been produced that enable to quantify human impact on the landscape since the introduction of agriculture. Application of these land cover maps in geomorphic models potentially allows to estimate the anthropogenic impact on sediment fluxes and thus to reconstruct changes in landscape morphology through time. However, current land cover reconstructions face some drawbacks. First of all, their low spatial resolution (i.e. 5 arc-minutes at best) questions their use in geomorphic models, as sub-catchment vegetation patterns play an important role in sediment dynamics. Existing global land cover reconstructions also do not differentiate the typology of human impact (cropland, grazing land, disturbed forests), although the susceptibility of different anthropogenic land uses towards erosion varies greatly. Finally, the various land cover reconstructions differ significantly regarding the estimated intensity of human impact for the preindustrial period. In this study, we assessed the performance of a spatially distributed erosion and sediment redistribution model that operates at high resolution (100 m) to the quality and spatial resolution of input land cover maps. This was done through a comparison of two sets of model runs. Firstly, low-resolution land cover (expressed as percentage of non-natural vegetation) maps were resampled to a spatial resolution of 100 m without differentiation of non-natural vegetation types. For the second set of model runs, estimated non-natural vegetation was differentiated in areas of cropland and grassland, and spatially allocated to a high-resolution grid (100 m) using a logistic model that relates contemporary land cover classes to slope, soil characteristics, landforms and distance to rivers. For both land cover maps, different scenarios for the ratio between cropland and grassland were simulated. Analyses were performed for several time periods throughout the Holocene, for the Scheldt River Basin (19,000 km2) in Belgium and northern France. Results indicate that low-resolution land cover information, regardless of the considered cropland/grassland ratio, leads to largely overestimated sediment fluxes when compared to field-based sediment budgets. Allocation of land cover to a higher spatial resolution yields far better results. Variations in model outcomes are related to differences in landscape connectivity between allocated and non-allocated land cover. These results point towards the need for higher-resolution land cover maps that incorporate the patchiness of vegetation at relevant scales regarding geomorphic processes. Also, model results with allocated and non-allocated land cover maps differ greatly for different cropland/grassland ratios. This indicates that there is not only a need for land cover reconstructions at high spatial resolution, but also that differentiation between cropland and grassland is essential for accurate geomorphic modeling. Further improvements in land cover reconstructions are thus needed before reliable quantitative estimates of anthropogenic impact on soil profiles and sediment redistribution can be simulated at continental scales. Detailed historic sediment budgets can provide an important tool not only for validating but also for reconstructing land cover histories.

A Strong Immune Response in Young Adult Honeybees Masks Their Increased Susceptibility to Infection Compared to Older Bees

PubMed Central

Bull, James C.; Ryabov, Eugene V.; Prince, Gill; Mead, Andrew; Zhang, Cunjin; Baxter, Laura A.; Pell, Judith K.; Osborne, Juliet L.; Chandler, Dave

2012-01-01

Honeybees, Apis mellifera, show age-related division of labor in which young adults perform maintenance (“housekeeping”) tasks inside the colony before switching to outside foraging at approximately 23 days old. Disease resistance is an important feature of honeybee biology, but little is known about the interaction of pathogens and age-related division of labor. We tested a hypothesis that older forager bees and younger “house” bees differ in susceptibility to infection. We coupled an infection bioassay with a functional analysis of gene expression in individual bees using a whole genome microarray. Forager bees treated with the entomopathogenic fungus Metarhizium anisopliae s.l. survived for significantly longer than house bees. This was concomitant with substantial differences in gene expression including genes associated with immune function. In house bees, infection was associated with differential expression of 35 candidate immune genes contrasted with differential expression of only two candidate immune genes in forager bees. For control bees (i.e. not treated with M. anisopliae) the development from the house to the forager stage was associated with differential expression of 49 candidate immune genes, including up-regulation of the antimicrobial peptide gene abaecin, plus major components of the Toll pathway, serine proteases, and serpins. We infer that reduced pathogen susceptibility in forager bees was associated with age-related activation of specific immune system pathways. Our findings contrast with the view that the immunocompetence in social insects declines with the onset of foraging as a result of a trade-off in the allocation of resources for foraging. The up-regulation of immune-related genes in young adult bees in response to M. anisopliae infection was an indicator of disease susceptibility; this also challenges previous research in social insects, in which an elevated immune status has been used as a marker of increased disease resistance and fitness without considering the effects of age-related development. PMID:23300441

Conserved and Differential Effects of Dietary Energy Intake on the Hippocampal Transcriptomes of Females and Males

PubMed Central

Martin, Bronwen; Pearson, Michele; Brenneman, Randall; Golden, Erin; Keselman, Alex; Iyun, Titilola; Carlson, Olga D.; Egan, Josephine M.; Becker, Kevin G.; Wood, William; Prabhu, Vinayakumar; de Cabo, Rafael

2008-01-01

The level of dietary energy intake influences metabolism, reproductive function, the development of age-related diseases, and even cognitive behavior. Because males and females typically play different roles in the acquisition and allocation of energy resources, we reasoned that dietary energy intake might differentially affect the brains of males and females at the molecular level. To test this hypothesis, we performed a gene array analysis of the hippocampus in male and female rats that had been maintained for 6 months on either ad libitum (control), 20% caloric restriction (CR), 40% CR, intermittent fasting (IF) or high fat/high glucose (HFG) diets. These diets resulted in expected changes in body weight, and circulating levels of glucose, insulin and leptin. However, the CR diets significantly increased the size of the hippocampus of females, but not males. Multiple genes were regulated coherently in response to energy restriction diets in females, but not in males. Functional physiological pathway analyses showed that the 20% CR diet down-regulated genes involved in glycolysis and mitochondrial ATP production in males, whereas these metabolic pathways were up-regulated in females. The 40% CR diet up-regulated genes involved in glycolysis, protein deacetylation, PGC-1α and mTor pathways in both sexes. IF down-regulated many genes in males including those involved in protein degradation and apoptosis, but up-regulated many genes in females including those involved in cellular energy metabolism, cell cycle regulation and protein deacetylation. Genes involved in energy metabolism, oxidative stress responses and cell death were affected by the HFG diet in both males and females. The gender-specific molecular genetic responses of hippocampal cells to variations in dietary energy intake identified in this study may mediate differential behavioral responses of males and females to differences in energy availability. PMID:18545695

Sexual dimorphism in a dioecious population of the wind-pollinated herb Mercurialis annua: the interactive effects of resource availability and competition.

PubMed

Hesse, Elze; Pannell, John R

2011-05-01

Male-biased sex allocation commonly occurs in wind-pollinated hermaphroditic plants, and is often positively associated with size, notably in terms of height. Currently, it is not well established whether a corresponding pattern holds for dioecious plants: do males of wind-pollinated species exhibit greater reproductive allocation than females? Here, sexual dimorphism is investigated in terms of life history trade-offs in a dioecious population of the wind-pollinated ruderal herb Mercurialis annua. The allocation strategies of males and females grown under different soil nutrient availability and competitive (i.e. no, male or female competitor) regimes were compared. Male reproductive allocation increased disproportionately with biomass, and was greater than that of females when grown in rich soils. Sexual morphs differentially adjusted their reproductive allocation in response to local environmental conditions. In particular, males reduced their reproductive allocation in poor soils, whereas females increased theirs, especially when competing with another female rather than growing alone. Finally, males displayed smaller above-ground vegetative sizes than females, but neither nutrient availability nor competition had a strong independent effect on relative size disparities between the sexes. Selection appears to favour plasticity in reproductive allocation in dioecious M. annua, thereby maintaining a relatively constant size hierarchy between sexual morphs. In common with other dioecious species, there seems to be little divergence in the niches occupied by males and females of M. annua.

Sexual dimorphism in a dioecious population of the wind-pollinated herb Mercurialis annua: the interactive effects of resource availability and competition

PubMed Central

Hesse, Elze; Pannell, John R.

2011-01-01

Background and Aims Male-biased sex allocation commonly occurs in wind-pollinated hermaphroditic plants, and is often positively associated with size, notably in terms of height. Currently, it is not well established whether a corresponding pattern holds for dioecious plants: do males of wind-pollinated species exhibit greater reproductive allocation than females? Here, sexual dimorphism is investigated in terms of life history trade-offs in a dioecious population of the wind-pollinated ruderal herb Mercurialis annua. Methods The allocation strategies of males and females grown under different soil nutrient availability and competitive (i.e. no, male or female competitor) regimes were compared. Key Results Male reproductive allocation increased disproportionately with biomass, and was greater than that of females when grown in rich soils. Sexual morphs differentially adjusted their reproductive allocation in response to local environmental conditions. In particular, males reduced their reproductive allocation in poor soils, whereas females increased theirs, especially when competing with another female rather than growing alone. Finally, males displayed smaller above-ground vegetative sizes than females, but neither nutrient availability nor competition had a strong independent effect on relative size disparities between the sexes. Conclusions Selection appears to favour plasticity in reproductive allocation in dioecious M. annua, thereby maintaining a relatively constant size hierarchy between sexual morphs. In common with other dioecious species, there seems to be little divergence in the niches occupied by males and females of M. annua. PMID:21385775

Network coding based joint signaling and dynamic bandwidth allocation scheme for inter optical network unit communication in passive optical networks

NASA Astrophysics Data System (ADS)

Wei, Pei; Gu, Rentao; Ji, Yuefeng

2014-06-01

As an innovative and promising technology, network coding has been introduced to passive optical networks (PON) in recent years to support inter optical network unit (ONU) communication, yet the signaling process and dynamic bandwidth allocation (DBA) in PON with network coding (NC-PON) still need further study. Thus, we propose a joint signaling and DBA scheme for efficiently supporting differentiated services of inter ONU communication in NC-PON. In the proposed joint scheme, the signaling process lays the foundation to fulfill network coding in PON, and it can not only avoid the potential threat to downstream security in previous schemes but also be suitable for the proposed hybrid dynamic bandwidth allocation (HDBA) scheme. In HDBA, a DBA cycle is divided into two sub-cycles for applying different coding, scheduling and bandwidth allocation strategies to differentiated classes of services. Besides, as network traffic load varies, the entire upstream transmission window for all REPORT messages slides accordingly, leaving the transmission time of one or two sub-cycles to overlap with the bandwidth allocation calculation time at the optical line terminal (the OLT), so that the upstream idle time can be efficiently eliminated. Performance evaluation results validate that compared with the existing two DBA algorithms deployed in NC-PON, HDBA demonstrates the best quality of service (QoS) support in terms of delay for all classes of services, especially guarantees the end-to-end delay bound of high class services. Specifically, HDBA can eliminate queuing delay and scheduling delay of high class services, reduce those of lower class services by at least 20%, and reduce the average end-to-end delay of all services over 50%. Moreover, HDBA also achieves the maximum delay fairness between coded and uncoded lower class services, and medium delay fairness for high class services.

Grandmothering and cognitive resources are required for the emergence of menopause and extensive post-reproductive lifespan.

PubMed

Aimé, Carla; André, Jean-Baptiste; Raymond, Michel

2017-07-01

Menopause, the permanent cessation of ovulation, occurs in humans well before the end of the expected lifespan, leading to an extensive post-reproductive period which remains a puzzle for evolutionary biologists. All human populations display this particularity; thus, it is difficult to empirically evaluate the conditions for its emergence. In this study, we used artificial neural networks to model the emergence and evolution of allocation decisions related to reproduction in simulated populations. When allocation decisions were allowed to freely evolve, both menopause and extensive post-reproductive life-span emerged under some ecological conditions. This result allowed us to test various hypotheses about the required conditions for the emergence of menopause and extensive post-reproductive life-span. Our findings did not support the Maternal Hypothesis (menopause has evolved to avoid the risk of dying in childbirth, which is higher in older women). In contrast, results supported a shared prediction from the Grandmother Hypothesis and the Embodied Capital Model. Indeed, we found that extensive post-reproductive lifespan allows resource reallocation to increase fertility of the children and survival of the grandchildren. Furthermore, neural capital development and the skill intensiveness of the foraging niche, rather than strength, played a major role in shaping the age profile of somatic and cognitive senescence in our simulated populations. This result supports the Embodied Capital Model rather than the Grand-Mother Hypothesis. Finally, in simulated populations where menopause had already evolved, we found that reduced post-reproductive lifespan lead to reduced children's fertility and grandchildren's survival. The results are discussed in the context of the evolutionary emergence of menopause and extensive post-reproductive life-span.

Castration, dopamine and food choice: a cost/benefit test in male hamsters.

PubMed

Chu, Lucy; Wood, Ruth I

2002-10-17

Testosterone is essential for copulation, and contributes to sexual motivation. In addition, castrated males are fatter and less active, suggesting that androgens may play a role in non-sexual behaviors, including food-related responses. To test this hypothesis, male hamsters were trained with a cost/benefit test, which compares operant responding for more-preferred food versus ad libitum consumption of lab chow. Males were tested before and after castration. The effect of the dopamine antagonist, haloperidol, on instrumental responses in intact and castrated males was also determined. Food-deprived hamsters responded vigorously for 45 mg Bio-Serv pellets in daily 30-min tests (665 presses, 6.0+/-0.9 g). When lab chow was available, males continued to respond for pellets (3.6+/-0.6 g) over chow ad libitum (1.2+/-0.3 g). Dopamine is central to this response because haloperidol (1.0 mg/kg i.p.) reversed food intake (pellets: 0.5+/-0.1 g; chow 2.0+/-0.5 g). Castration had no effect on operant responding for pellets alone (6.6+/-0.7 g). When chow was present, castrates consumed an even greater proportion of their total food intake as pellets [6.0+/-0.4 g pellets (92%), 1.6+/-0.5 g chow (8%), vs. 75 and 25%, respectively, for intact males]. This is contrary to our original hypothesis. In addition, castration did not change the effects of haloperidol on food intake: (0.4+/-0.1 g pellets; 1.6+/-0.5 g chow). These results support previous findings in rats that dopamine affects response allocation in a cost/benefit test. However, they do not support the hypothesis that testosterone modifies the allocation of food-related responses.

Testing the carotenoid trade-off hypothesis in the polychromatic Midas cichlid, Amphilophus citrinellus.

PubMed

Lin, Susan M; Nieves-Puigdoller, Katherine; Brown, Alexandria C; McGraw, Kevin J; Clotfelter, Ethan D

2010-01-01

Many animals use carotenoid pigments derived from their diet for coloration and immunity. The carotenoid trade-off hypothesis predicts that, under conditions of carotenoid scarcity, individuals may be forced to allocate limited carotenoids to either coloration or immunity. In polychromatic species, the pattern of allocation may differ among individuals. We tested the carotenoid trade-off hypothesis in the Midas cichlid, Amphilophus citrinellus, a species with two ontogenetic color morphs, barred and gold, the latter of which is the result of carotenoid expression. We performed a diet-supplementation experiment in which cichlids of both color morphs were assigned to one of two diet treatments that differed only in carotenoid content (beta-carotene, lutein, and zeaxanthin). We measured integument color using spectrometry, quantified carotenoid concentrations in tissue and plasma, and assessed innate immunity using lysozyme activity and alternative complement pathway assays. In both color morphs, dietary carotenoid supplementation elevated plasma carotenoid circulation but failed to affect skin coloration. Consistent with observable differences in integument coloration, we found that gold fish sequestered more carotenoids in skin tissue than barred fish, but barred fish had higher concentrations of carotenoids in plasma than gold fish. Neither measure of innate immunity differed between gold and barred fish, or as a function of dietary carotenoid supplementation. Lysozyme activity, but not complement activity, was strongly affected by body condition. Our data show that a diet low in carotenoids is sufficient to maintain both coloration and innate immunity in Midas cichlids. Our data also suggest that the developmental transition from the barred to gold morph is not accompanied by a decrease in innate immunity in this species.

Optimal plant nitrogen use improves model representation of vegetation response to elevated CO2

NASA Astrophysics Data System (ADS)

Caldararu, Silvia; Kern, Melanie; Engel, Jan; Zaehle, Sönke

2017-04-01

Existing global vegetation models often cannot accurately represent observed ecosystem behaviour under transient conditions such as elevated atmospheric CO2, a problem that can be attributed to an inflexibility in model representation of plant responses. Plant optimality concepts have been proposed as a solution to this problem as they offer a way to represent plastic plant responses in complex models. Here we present a novel, next generation vegetation model which includes optimal nitrogen allocation to and within the canopy as well as optimal biomass allocation between above- and belowground components in response to nutrient and water availability. The underlying hypothesis is that plants adjust their use of nitrogen in response to environmental conditions and nutrient availability in order to maximise biomass growth. We show that for two FACE (Free Air CO2 enrichment) experiments, the Duke forest and Oak Ridge forest sites, the model can better predict vegetation responses over the duration of the experiment when optimal processes are included. Specifically, under elevated CO2 conditions, the model predicts a lower optimal leaf N concentration as well as increased biomass allocation to fine roots, which, combined with a redistribution of leaf N between the Rubisco and chlorophyll components, leads to a continued NPP response under high CO2, where models with a fixed canopy stoichiometry predict a quick onset of N limitation.Existing global vegetation models often cannot accurately represent observed ecosystem behaviour under transient conditions such as elevated atmospheric CO2, a problem that can be attributed to an inflexibility in model representation of plant responses. Plant optimality concepts have been proposed as a solution to this problem as they offer a way to represent plastic plant responses in complex models. Here we present a novel, next generation vegetation model which includes optimal nitrogen allocation to and within the canopy as well as optimal biomass allocation between above- and belowground components in response to nutrient and water availability. The underlying hypothesis is that plants adjust their use of nitrogen in response to environmental conditions and nutrient availability in order to maximise biomass growth. We show that for two FACE (Free Air CO2 enrichment) experiments, the Duke forest and Oak Ridge forest sites, the model can better predict vegetation responses over the duration of the experiment when optimal processes are included. Specifically, under elevated CO2 conditions, the model predicts a lower optimal leaf N concentration as well as increased biomass allocation to fine roots, which, combined with a redistribution of leaf N between the Rubisco and chlorophyll components, leads to a continued NPP response under high CO2, where models with a fixed canopy stoichiometry predict a quick onset of N limitation.

Irrigation water allocation optimization using multi-objective evolutionary algorithm (MOEA) - a review

NASA Astrophysics Data System (ADS)

Fanuel, Ibrahim Mwita; Mushi, Allen; Kajunguri, Damian

2018-03-01

This paper analyzes more than 40 papers with a restricted area of application of Multi-Objective Genetic Algorithm, Non-Dominated Sorting Genetic Algorithm-II and Multi-Objective Differential Evolution (MODE) to solve the multi-objective problem in agricultural water management. The paper focused on different application aspects which include water allocation, irrigation planning, crop pattern and allocation of available land. The performance and results of these techniques are discussed. The review finds that there is a potential to use MODE to analyzed the multi-objective problem, the application is more significance due to its advantage of being simple and powerful technique than any Evolutionary Algorithm. The paper concludes with the hopeful new trend of research that demand effective use of MODE; inclusion of benefits derived from farm byproducts and production costs into the model.

Induction of CD4 T cell memory by local cellular collectivity.

PubMed

Polonsky, Michal; Rimer, Jacob; Kern-Perets, Amos; Zaretsky, Irina; Miller, Stav; Bornstein, Chamutal; David, Eyal; Kopelman, Naama Meira; Stelzer, Gil; Porat, Ziv; Chain, Benjamin; Friedman, Nir

2018-06-15

Cell differentiation is directed by signals driving progenitors into specialized cell types. This process can involve collective decision-making, when differentiating cells determine their lineage choice by interacting with each other. We used live-cell imaging in microwell arrays to study collective processes affecting differentiation of naïve CD4 + T cells into memory precursors. We found that differentiation of precursor memory T cells sharply increases above a threshold number of locally interacting cells. These homotypic interactions involve the cytokines interleukin-2 (IL-2) and IL-6, which affect memory differentiation orthogonal to their effect on proliferation and survival. Mathematical modeling suggests that the differentiation rate is continuously modulated by the instantaneous number of locally interacting cells. This cellular collectivity can prioritize allocation of immune memory to stronger responses. Copyright © 2018, American Association for the Advancement of Science.

Gene and environment interaction: is the differential susceptibility hypothesis relevant for obesity?

PubMed Central

Dalle Molle, Roberta; Fatemi, Hajar; Dagher, Alain; Levitan, Robert D.; Silveira, Patricia P.; Dubé, Laurette

2017-01-01

The differential susceptibility model states that a given genetic variant is associated with an increased risk of pathology in negative environments but greater than average resilience in enriched ones. While this theory was first implemented in psychiatric-genetic research, it may also help us to unravel the complex ways that genes and environments interact to influence feeding behavior and obesity. We reviewed evidence on gene vs. environment interactions that influence obesity development, aiming to support the applicability of the differential susceptibility model for this condition, and propose that various environmental “layers” relevant for human development should be considered when bearing the differential susceptibility model in mind. Mother-child relationship, socioeconomic status and individual's response are important modifiers of BMI and food intake when interacting with gene variants, “for better and for worse”. While only a few studies to date have investigated obesity outcomes using this approach, we propose that the differential susceptibility hypothesis is in fact highly applicable to the study of genetic and environmental influences on feeding behavior and obesity risk. PMID:28024828

S4HARA: System for HIV/AIDS resource allocation.

PubMed

Lasry, Arielle; Carter, Michael W; Zaric, Gregory S

2008-03-26

HIV/AIDS resource allocation decisions are influenced by political, social, ethical and other factors that are difficult to quantify. Consequently, quantitative models of HIV/AIDS resource allocation have had limited impact on actual spending decisions. We propose a decision-support System for HIV/AIDS Resource Allocation (S4HARA) that takes into consideration both principles of efficient resource allocation and the role of non-quantifiable influences on the decision-making process for resource allocation. S4HARA is a four-step spreadsheet-based model. The first step serves to identify the factors currently influencing HIV/AIDS allocation decisions. The second step consists of prioritizing HIV/AIDS interventions. The third step involves allocating the budget to the HIV/AIDS interventions using a rational approach. Decision-makers can select from several rational models of resource allocation depending on availability of data and level of complexity. The last step combines the results of the first and third steps to highlight the influencing factors that act as barriers or facilitators to the results suggested by the rational resource allocation approach. Actionable recommendations are then made to improve the allocation. We illustrate S4HARA in the context of a primary healthcare clinic in South Africa. The clinic offers six types of HIV/AIDS interventions and spends US$750,000 annually on these programs. Current allocation decisions are influenced by donors, NGOs and the government as well as by ethical and religious factors. Without additional funding, an optimal allocation of the total budget suggests that the portion allotted to condom distribution be increased from 1% to 15% and the portion allotted to prevention and treatment of opportunistic infections be increased from 43% to 71%, while allocation to other interventions should decrease. Condom uptake at the clinic should be increased by changing the condom distribution policy from a pull system to a push system. NGOs and donors promoting antiretroviral programs at the clinic should be sensitized to the results of the model and urged to invest in wellness programs aimed at the prevention and treatment of opportunistic infections. S4HARA differentiates itself from other decision support tools by providing rational HIV/AIDS resource allocation capabilities as well as consideration of the realities facing authorities in their decision-making process.

Changes and Challenges in Canadian Dental Faculties.

ERIC Educational Resources Information Center

Clark, D. Christopher; And Others

1992-01-01

A survey of 254 Canadian dental faculty investigated changing career interests, sources of satisfaction, and professional development needs. Results indicate desire to adjust time allocation among research, teaching, and administration; satisfaction with recognition for teaching; and discontent over differential status among teachers, clinicians,…

Simulating the Pattern of Right-Hemisphere-Damaged Patients for the Processing of the Alternative Metaphorical Meanings of Words: Evidence in Favor of a Cognitive Resources Hypothesis

ERIC Educational Resources Information Center

Monetta, Laura; Ouellet-Plamondon, Clairelaine; Joanette, Yves

2006-01-01

Lately, many studies have suggested that communication impairments in brain-damaged individuals might be explained--at least in part--in terms of cognitive resource allocation. Reproducing a clinical pattern in normal subjects by using a dual-task treatment might be a way of evaluating the role of cognitive resources in the right hemisphere's…

Pattern of money allocation in experimental games supports the stress hypothesis of gender differences in Toxoplasma gondii-induced behavioural changes.

PubMed

Lindová, Jitka; Kubena, Ales A; Sturcová, Hana; Krivohlavá, Romana; Novotná, Martina; Rubesová, Anna; Havlícek, Jan; Kodym, Petr; Flegr, Jaroslav

2010-06-01

Latent toxoplasmosis has been previously found to cause behavioural and personality changes in humans, which are specific for each gender. Here we tested the stress hypothesis of these gender differences based on the assumption that latent toxoplasmosis causes long-term subliminal stress. In line with this hypothesis, the gender difference will appear specifically in situations with interpersonal context because in contrast to the typical individualistic coping style of men, women have a tendency to express elevated prosocial behaviour under stress. Altogether 295 biology students (29/191 females and 27/104 males infected by T. gondii) played a modified version of the Dictator Game and the Trust Game. As predicted, a gender difference in the effect of latent toxoplasmosis was found for the measure of reciprocal altruism in the Trust Game (p = 0.016), but both genders appeared less generous when infected in the Dictator Game modified to minimize social connotation (p = 0.048).

The Size Advantage Model of Sex Allocation in the Protandrous Sex-Changer Crepidula fornicata: Role of the Mating System, Sperm Storage, and Male Mobility.

PubMed

Broquet, Thomas; Barranger, Audrey; Billard, Emmanuelle; Bestin, Anastasia; Berger, Rémy; Honnaert, Gaelle; Viard, Frédérique

2015-09-01

Sequential hermaphroditism is adaptive when the reproductive value of an individual varies with size or age, and this relationship differs between males and females. In this case, theory shows that the lifetime reproductive output of an individual is increased by changing sex (a hypothesis referred to as the size-advantage model). Sex-linked differences in size-fitness curves can stem from differential costs of reproduction, the mating system, and differences in growth and mortality between sexes. Detailed empirical data is required to disentangle the relative roles of each of these factors within the theory. Quantitative data are also needed to explore the role of sperm storage, which has not yet been considered with sequential hermaphrodites. Using experimental rearing and paternity assignment, we report relationships between size and reproductive success of Crepidula fornicata, a protandrous (male-first) gastropod. Male reproductive success increased with size due to the polygamous system and stacking behavior of the species, but females nonetheless had greater reproductive success than males of the same size, in agreement with the size-advantage theory. Sperm storage appeared to be a critical determinant of success for both sexes, and modeling the effect of sperm storage showed that it could potentially accelerate sex change in protandrous species.

Noninferiority trial designs for odds ratios and risk differences.

PubMed

Hilton, Joan F

2010-04-30

This study presents constrained maximum likelihood derivations of the design parameters of noninferiority trials for binary outcomes with the margin defined on the odds ratio (ψ) or risk-difference (δ) scale. The derivations show that, for trials in which the group-specific response rates are equal under the point-alternative hypothesis, the common response rate, π(N), is a fixed design parameter whose value lies between the control and experimental rates hypothesized at the point-null, {π(C), π(E)}. We show that setting π(N) equal to the value of π(C) that holds under H(0) underestimates the overall sample size requirement. Given {π(C), ψ} or {π(C), δ} and the type I and II error rates, or algorithm finds clinically meaningful design values of π(N), and the corresponding minimum asymptotic sample size, N=n(E)+n(C), and optimal allocation ratio, γ=n(E)/n(C). We find that optimal allocations are increasingly imbalanced as ψ increases, with γ(ψ)<1 and γ(δ)≈1/γ(ψ), and that ranges of allocation ratios map to the minimum sample size. The latter characteristic allows trialists to consider trade-offs between optimal allocation at a smaller N and a preferred allocation at a larger N. For designs with relatively large margins (e.g. ψ>2.5), trial results that are presented on both scales will differ in power, with more power lost if the study is designed on the risk-difference scale and reported on the odds ratio scale than vice versa. 2010 John Wiley & Sons, Ltd.

Visibility vs. biomass in flowers: exploring corolla allocation in Mediterranean entomophilous plants.

PubMed

Herrera, Javier

2009-05-01

While pollinators may in general select for large, morphologically uniform floral phenotypes, drought stress has been proposed as a destabilizing force that may favour small flowers and/or promote floral variation within species. The general validity of this concept was checked by surveying a taxonomically diverse array of 38 insect-pollinated Mediterranean species. The interplay between fresh biomass investment, linear size and percentage corolla allocation was studied. Allometric relationships between traits were investigated by reduced major-axis regression, and qualitative correlates of floral variation explored using general linear-model MANOVA. Across species, flowers were perfectly isometrical with regard to corolla allocation (i.e. larger flowers were just scaled-up versions of smaller ones and vice versa). In contrast, linear size and biomass varied allometrically (i.e. there were shape variations, in addition to variations in size). Most floral variables correlated positively and significantly across species, except corolla allocation, which was largely determined by family membership and floral symmetry. On average, species with bilateral flowers allocated more to the corolla than those with radial flowers. Plant life-form was immaterial to all of the studied traits. Flower linear size variation was in general low among conspecifics (coefficients of variation around 10 %), whereas biomass was in general less uniform (e.g. 200-400 mg in Cistus salvifolius). Significant among-population differences were detected for all major quantitative floral traits. Flower miniaturization can allow an improved use of reproductive resources under prevailingly stressful conditions. The hypothesis that flower size reflects a compromise between pollinator attraction, water requirements and allometric constraints among floral parts is discussed.

Schooling for Inequality.

ERIC Educational Resources Information Center

Smith, Dorothy E.

2000-01-01

Inequalities produced by the school system are an important topic for feminist thought and debate. Schools are an integral part of the institutional processes for the differential allocation of agency. They reproduce the social organization of inequality and exclusion at multiple levels. School systems are well-insulated from change initiatives…

Why does primary angioplasty not work in registries? Quantifying the susceptibility of real-world comparative effectiveness data to allocation bias.

PubMed

Sen, Sayan; Davies, Justin E; Malik, Iqbal S; Foale, Rodney A; Mikhail, Ghada W; Hadjiloizou, Nearchos; Hughes, Alun; Mayet, Jamil; Francis, Darrel P

2012-11-01

Meta-analysis of registries (comparative effectiveness research) shows that primary angioplasty and fibrinolysis have equivalent real-world survival. Yet, randomized, controlled trials consistently find primary angioplasty superior. Can unequal allocation of higher-risk patients in registries have masked primary angioplasty benefit? First, we constructed a model to demonstrate the potential effect of allocation bias. We then analyzed published registries (55022 patients) for allocation of higher-risk patients (Killip class ≥1) to determine whether the choice of reperfusion therapy was affected by the risk level of the patient. Meta-regression was used to examine the relationship between differences in allocation of high-risk patient to primary angioplasty or fibrinolysis and mortality. Initial modeling suggested that registry outcomes are sensitive to allocation bias of high-risk patients. Across the registries, the therapy receiving excess high-risk patients had worse mortality. Unequal distribution of high-risk status accounted for most of the between-registry variance (adjusted R(2)(meta)=83.1%). Accounting for differential allocation of higher-risk patients, primary angioplasty gave 22% lower mortality (odds ratio, 0.78; 95% confidence interval, 0.64-0.97; P=0.029). We derive a formula, called the number needed to abolish, highlighting situations in which comparative effectiveness studies are particularly vulnerable to this bias. In ST-segment elevation myocardial infarction, clinicians' preference for management of a few high-risk patients can shift mortality substantially. Comparative effectiveness research in any disease is vulnerable to this, especially diseases with an immediately identifiable high-risk subgroup that clinicians prefer to allocate to 1 therapy. For this reason, preliminary indications from registry-based comparative effectiveness research should be definitively tested by randomized, controlled trials.

Prosocial Personality Traits Differentially Predict Egalitarianism, Generosity, and Reciprocity in Economic Games

PubMed Central

Zhao, Kun; Ferguson, Eamonn; Smillie, Luke D.

2016-01-01

Recent research has highlighted the role of prosocial personality traits—agreeableness and honesty-humility—in egalitarian distributions of wealth in the dictator game. Expanding on these findings, we ran two studies to examine individual differences in two other forms of prosociality—generosity and reciprocity—with respect to two major models of personality, the Big Five and the HEXACO. Participants (combined N = 560) completed a series of economic games in which allocations in the dictator game were compared with those in the generosity game, a non-constant-sum wealth distribution task where proposers with fixed payoffs selected the size of their partner’s payoff (“generosity”). We further examined positive and negative reciprocity by manipulating a partner’s previous move (“reciprocity”). Results showed clear evidence of both generosity and positive reciprocity in social preferences, with allocations to a partner greater in the generosity game than in the dictator game, and greater still when a player had been previously assisted by their partner. There was also a consistent interaction with gender, whereby men were more generous when this was costless and women were more egalitarian overall. Furthermore, these distinct forms of prosociality were differentially predicted by personality traits, in line with the core features of these traits and the theoretical distinctions between them. HEXACO honesty-humility predicted dictator, but not generosity allocations, while traits capturing tendencies toward irritability and anger predicted lower generosity, but not dictator allocations. In contrast, the politeness—but not compassion—aspect of Big Five agreeableness was uniquely and broadly associated with prosociality across all games. These findings support the discriminant validity between related prosocial constructs, and have important implications for understanding the motives and mechanisms taking place within economic games. PMID:27555824

Prosocial Personality Traits Differentially Predict Egalitarianism, Generosity, and Reciprocity in Economic Games.

PubMed

Zhao, Kun; Ferguson, Eamonn; Smillie, Luke D

2016-01-01

Recent research has highlighted the role of prosocial personality traits-agreeableness and honesty-humility-in egalitarian distributions of wealth in the dictator game. Expanding on these findings, we ran two studies to examine individual differences in two other forms of prosociality-generosity and reciprocity-with respect to two major models of personality, the Big Five and the HEXACO. Participants (combined N = 560) completed a series of economic games in which allocations in the dictator game were compared with those in the generosity game, a non-constant-sum wealth distribution task where proposers with fixed payoffs selected the size of their partner's payoff ("generosity"). We further examined positive and negative reciprocity by manipulating a partner's previous move ("reciprocity"). Results showed clear evidence of both generosity and positive reciprocity in social preferences, with allocations to a partner greater in the generosity game than in the dictator game, and greater still when a player had been previously assisted by their partner. There was also a consistent interaction with gender, whereby men were more generous when this was costless and women were more egalitarian overall. Furthermore, these distinct forms of prosociality were differentially predicted by personality traits, in line with the core features of these traits and the theoretical distinctions between them. HEXACO honesty-humility predicted dictator, but not generosity allocations, while traits capturing tendencies toward irritability and anger predicted lower generosity, but not dictator allocations. In contrast, the politeness-but not compassion-aspect of Big Five agreeableness was uniquely and broadly associated with prosociality across all games. These findings support the discriminant validity between related prosocial constructs, and have important implications for understanding the motives and mechanisms taking place within economic games.

METHYLMERCURY IMPAIRS NEURONAL DIFFERENTIATION BY ALTERING NEUROTROPHIN SIGNALING.

EPA Science Inventory

In previous in vivo studies, we observed that developmental exposure to CH3Hg can alter neocortical morphology and neurotrophin signaling. Using primed PC12 cells as a model system for neuronal differentiation, we examined the hypothesis that the developmental effects of CH3Hg ma...

Cognitive Correlates of Language: Differential Criteria Yield Differential Results.

ERIC Educational Resources Information Center

Corrigan, Roberta

1979-01-01

Explores the hypothesis that representation, as measured by object permanence attainment, is the main prerequisite for language acquisition. Differing definitions of representation, differing assumptions about cognitive stages, and differing criteria for assessing cognitive abilities such as object permanence may account for some of the divergent…

Contracting in the National Health Service (NHS): recognizing the need for co-operation.

PubMed

Joslyn, E

1997-05-01

Within the reorganized National Health Service hierarchical relationships between Health Authorities and Trusts have been replaced by functional differentiation. However, differentiation of function cannot be seen as an end in itself and management of the relationship between purchasers and providers must include managing the differentiation as well as the function. This paper suggests that collaborative and administrative activities have a distinct role to play in health service management. The paper suggests that in health service management market strategies are likely to dominate in relation to resource allocation activities. The paper also argues that administrative strategies are likely to be necessary within the internal market system--to bridge the gap resulting from the differentiation of function.

Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes.

PubMed

Camossi, L G; Greca-Júnior, H; Corrêa, A P F L; Richini-Pereira, V B; Silva, R C; Da Silva, A V; Langoni, H

2011-05-11

Toxoplasmosis is the major parasitic disease affecting sheep. It is important for veterinary medicine, animal science and public health since it causes reproductive and economic losses in the herd, as well as damaging human health due to consumption of contaminated meat and milk, which can facilitate zoonotic transmission. Detection of Toxoplasma gondii in ovine milk and lack of data in the literature describing differentiation between acute and chronic disease for this species stimulated the elaboration of the present research project. To achieve the aim of this study, the animals were allocated to two groups of 20 ewes each, of which group 1 was composed of animals with positive serology and group 2 with negative serology. Acute and chronic stages of the disease were differentiated by modified direct agglutination test (MAT), in which antigens were fixed with formalin (MAT-AF) and methanol (MAT-AM). The parasite was detected in milk by polymerase chain reaction (PCR), and the molecular identity of the amplified products was confirmed by sequencing. The serological results indicated that sheep had a chronic infection profile. T. gondii DNA was detected in seven milk samples from five seropositive sheep, and twice in milk of two sheep. Sequences of species shared 97-100% identity with T. gondii. These findings allowed the hypothesis that the peripartum period may also lead to the resurgence of tissue T. gondii tachyzoites cysts which can circulate again and be excreted in the milk. This study used sheep naturally infected with T. gondii as a prerequisite for further investigations on the possible participation of this species in toxoplasmosis epidemiology and as a potential transmission route related to consumption of milk from infected sheep. Copyright © 2010 Elsevier B.V. All rights reserved.

RNA-seq transcriptome profiling reveals that Medicago truncatula nodules acclimate N2 fixation before emerging P deficiency reaches the nodules

PubMed Central

Cabeza, Ricardo A.; Liese, Rebecca; Lingner, Annika; von Stieglitz, Ilsabe; Neumann, Janice; Salinas-Riester, Gabriela; Pommerenke, Claudia; Dittert, Klaus; Schulze, Joachim

2014-01-01

Legume nodules are plant tissues with an exceptionally high concentration of phosphorus (P), which, when there is scarcity of P, is preferentially maintained there rather than being allocated to other plant organs. The hypothesis of this study was that nodules are affected before the P concentration in the organ declines during whole-plant P depletion. Nitrogen (N2) fixation and P concentration in various organs were monitored during a whole-plant P-depletion process in Medicago truncatula. Nodule gene expression was profiled through RNA-seq at day 5 of P depletion. Until that point in time P concentration in leaves reached a lower threshold but was maintained in nodules. N2-fixation activity per plant diverged from that of fully nourished plants beginning at day 5 of the P-depletion process, primarily because fewer nodules were being formed, while the activity of the existing nodules was maintained for as long as two weeks into P depletion. RNA-seq revealed nodule acclimation on a molecular level with a total of 1140 differentially expressed genes. Numerous genes for P remobilization from organic structures were increasingly expressed. Various genes involved in nodule malate formation were upregulated, while genes involved in fermentation were downregulated. The fact that nodule formation was strongly repressed with the onset of P deficiency is reflected in the differential expression of various genes involved in nodulation. It is concluded that plants follow a strategy to maintain N2 fixation and viable leaf tissue as long as possible during whole-plant P depletion to maintain their ability to react to emerging new P sources (e.g. through active P acquisition by roots). PMID:25151618

A lifetime portfolio of risky and risk-free sexual behaviour and the prevalence of AIDS.

PubMed

Levy, Amnon

2002-11-01

A lifetime portfolio of risky and risk-free sexual activities is conceptually constructed in this paper. People's time allocation between risky and risk-free sexual activities affects, and is affected by, the prevalence of AIDS. A small satisfaction differential between risky and risk-free sex can lead to a significant prevalence of AIDS. Numerical simulations suggest that the reduction in the prevalence of AIDS generated by a 1% improvement in the sensual quality of freely distributed condoms can be 0.855% when the initial satisfaction differential between risky and risk-free sex is 50% or 0.464% when the initial satisfaction differential is 100%.

The Soft Constraints Hypothesis: A Rational Analysis Approach to Resource Allocation for Interactive Behavior

DTIC Science & Technology

2006-01-01

Gray, Rensselaer Polytechnic Institute, Carnegie Building, 110 8th St., Troy, NY 12180. E-mail: grayw@rpi.edu Psychological Review Copyright 2006 by...the American Psychological Association 2006, Vol. 113, No. 3, 461–482 0033-295X/06/$12.00 DOI: 10.1037/0033-295X.113.3.461 461 Report Documentation...analysis approach from signal-detection theorists (Geisler, 2003; Macmillan & Creelman , 2004) with rational analysis (Anderson, 1990, 1991) to present an

Do Brothers Affect Their Sisters' Chances to Graduate? An Analysis of Sibling Sex Composition Effects on Graduation from a University or a "Fachhochschule" in Germany

ERIC Educational Resources Information Center

Jacob, Marita

2011-01-01

In a recent paper on gender inequality in higher education Buchman and DiPrete (2006) assume that the decrease in the gender gap in college completion in the US can partly be explained by changes in the allocation of familial resources in favour of women. However, they do not test this hypothesis empirically. In this paper I examine the effects of…

Educational Differences in Age-Related Patterns of Disease: Reconsidering the Cumulative Disadvantage and Age-as-Leveler Hypotheses

ERIC Educational Resources Information Center

Dupre, Matthew E.

2007-01-01

Some studies suggest that the relationship between education and health strengthens with age (cumulative disadvantage hypothesis), while other studies find that it weakens (age-as-leveler hypothesis). This research addresses this inconsistency by differentiating individual-level changes in health from those occurring at the aggregate level due to…

Defective Number Sense or Impaired Access? Differential Impairments in Different Subgroups of Children with Mathematics Difficulties

ERIC Educational Resources Information Center

Wong, Terry T.-Y.; Ho, Connie S.-H.; Tang, Joey

2017-01-01

Developmental dyscalculia (DD) is a specific learning disability in mathematics that affects around 6% of the population. Currently, the core deficit of DD remains unknown. While the number sense deficit hypothesis suggests that the core deficit of DD lies in the inability to represent nonsymbolic numerosity, the access deficit hypothesis suggests…

Competition Unleashed: Horizontal Differentiation in German Higher Education

ERIC Educational Resources Information Center

Erhardt, Dominik; von Kotzebue, Alexander

2016-01-01

Unlike in the US and other western countries, the higher education market in Germany has been sheltered from competition. This changed recently, when a governmental "excellence initiative" began to allocate substantial supplementary funds dependent on higher education institutions' performance, in 2005. This study is aimed at assessing…

Heat stress differentially modifies ethylene biosynthesis and signaling in pea floral and fruit tissues.

PubMed

Savada, Raghavendra P; Ozga, Jocelyn A; Jayasinghege, Charitha P A; Waduthanthri, Kosala D; Reinecke, Dennis M

2017-10-01

Ethylene biosynthesis is regulated in reproductive tissues in response to heat stress in a manner to optimize resource allocation to pollinated fruits with developing seeds. High temperatures during reproductive development are particularly detrimental to crop fruit/seed production. Ethylene plays vital roles in plant development and abiotic stress responses; however, little is known about ethylene's role in reproductive tissues during development under heat stress. We assessed ethylene biosynthesis and signaling regulation within the reproductive and associated tissues of pea during the developmental phase that sets the stage for fruit-set and seed development under normal and heat-stress conditions. The transcript abundance profiles of PsACS [encode enzymes that convert S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylic acid (ACC)] and PsACO (encode enzymes that convert ACC to ethylene), and ethylene evolution were developmentally, environmentally, and tissue-specifically regulated in the floral/fruit/pedicel tissues of pea. Higher transcript abundance of PsACS and PsACO in the ovaries, and PsACO in the pedicels was correlated with higher ethylene evolution and ovary senescence and pedicel abscission in fruits that were not pollinated under control temperature conditions. Under heat-stress conditions, up-regulation of ethylene biosynthesis gene expression in pre-pollinated ovaries was also associated with higher ethylene evolution and lower retention of these fruits. Following successful pollination and ovule fertilization, heat-stress modified PsACS and PsACO transcript profiles in a manner that suppressed ovary ethylene evolution. The normal ethylene burst in the stigma/style and petals following pollination was also suppressed by heat-stress. Transcript abundance profiles of ethylene receptor and signaling-related genes acted as qualitative markers of tissue ethylene signaling events. These data support the hypothesis that ethylene biosynthesis is regulated in reproductive tissues in response to heat stress to modulate resource allocation dynamics.

Differential expression of the phthalate syndrome in male Sprague-Dawley and Wistar rats after in utero DEHP exposure

EPA Science Inventory

Exposure to phthalate esters during sexual differentiation disrupts testosterone and insulin-like three hormones resulting in malformations of androgen- and insulin-like three-dependent tissues. The current study was designed to test the hypothesis that gubernacular lesions would...

An Investigation of the Relationship between Cognitive Reactivity and Rumination

ERIC Educational Resources Information Center

Moulds, Michelle L.; Kandris, Eva; Williams, Alishia D.; Lang, Tamara; Yap, Carol; Hoffmeister, Karolin

2008-01-01

Teasdale's (Teasdale, J.D. (1988). Cognitive vulnerability to persistent depression. "Cognition and Emotion," 2, 247-274) differential activation hypothesis refers to the ease with which maladaptive cognitive processes are triggered by mild dysphoria as "cognitive reactivity." Supporting this model is evidence of a differential association between…

Affirmative action and the allocation of health care.

PubMed

Francis, L P

1999-09-01

The justifications of affirmative action, the compensatory, corrective and redistributive, have been widely recognized in legal thinking. They have been applied, principally, to employment practices. They can also be applied to health care. Arguments for affirmative action in health care allocation shift the burden of proof to those who deny that racism is the root cause of differential morbidity and mortality experienced by, for example, African Americans. At the very least, these arguments mandate much needed research into the causes of minorities' poor health. Without such research, racism remains the presumptive cause of, and affirmative action the appropriate remedy for, the health care problems minorities face.

Reliability and the adaptive utility of discrimination among alarm callers.

PubMed

Blumstein, Daniel T; Verneyre, Laure; Daniel, Janice C

2004-09-07

Unlike individually distinctive contact calls, or calls that aid in the recognition of young by their parents, the function or functions of individually distinctive alarm calls is less obvious. We conducted three experiments to study the importance of caller reliability in explaining individual-discriminative abilities in the alarm calls of yellow-bellied marmots (Marmota flaviventris). In our first two experiments, we found that calls from less reliable individuals and calls from individuals calling from a greater simulated distance were more evocative than calls from reliable individuals or nearby callers. These results are consistent with the hypothesis that marmots assess the reliability of callers to help them decide how much time to allocate to independent vigilance. The third experiment demonstrated that the number of callers influenced responsiveness, probably because situations where more than a single caller calls, are those when there is certain to be a predator present. Taken together, the results from all three experiments demonstrate the importance of reliability in explaining individual discrimination abilities in yellow-bellied marmots. Marmots' assessment of reliability acts by influencing the time allocated to individual assessment and thus the time not allocated to other activities.

Reliability and the adaptive utility of discrimination among alarm callers.

PubMed Central

Blumstein, Daniel T.; Verneyre, Laure; Daniel, Janice C.

2004-01-01

Unlike individually distinctive contact calls, or calls that aid in the recognition of young by their parents, the function or functions of individually distinctive alarm calls is less obvious. We conducted three experiments to study the importance of caller reliability in explaining individual-discriminative abilities in the alarm calls of yellow-bellied marmots (Marmota flaviventris). In our first two experiments, we found that calls from less reliable individuals and calls from individuals calling from a greater simulated distance were more evocative than calls from reliable individuals or nearby callers. These results are consistent with the hypothesis that marmots assess the reliability of callers to help them decide how much time to allocate to independent vigilance. The third experiment demonstrated that the number of callers influenced responsiveness, probably because situations where more than a single caller calls, are those when there is certain to be a predator present. Taken together, the results from all three experiments demonstrate the importance of reliability in explaining individual discrimination abilities in yellow-bellied marmots. Marmots' assessment of reliability acts by influencing the time allocated to individual assessment and thus the time not allocated to other activities. PMID:15315902

Modelling the effect of environmental factors on resource allocation in mixed plants systems

NASA Astrophysics Data System (ADS)

Gayler, Sebastian; Priesack, Eckart

2010-05-01

In most cases, growth of plants is determined by competition against neighbours for the local resources light, water and nutrients and by defending against herbivores and pathogens. Consequently, it is important for a plant to grow fast without neglecting defence. However, plant internal substrates and energy required to support maintenance, growth and defence are limited and the total demand for these processes cannot be met in most cases. Therefore, allocation of carbohydrates to growth related primary metabolism or to defence related secondary metabolism can be seen as a trade-off between the demand of plants for being competitive against neighbours and for being more resistant against pathogens. A modelling approach is presented which can be used to simulate competition for light, water and nutrients between plant individuals in mixed canopies. The balance of resource allocation between growth processes and synthesis of secondary compounds is modelled by a concept originating from different plant defence hypothesis. The model is used to analyse the impact of environmental factors such as soil water and nitrogen availability, planting density and atmospheric concentration of CO2 on growth of plant individuals within mixed canopies and variations in concentration of carbon-based secondary metabolites in plant tissues.

Testing the activitystat hypothesis: a randomised controlled trial protocol.

PubMed

Gomersall, Sjaan; Maher, Carol; Norton, Kevin; Dollman, Jim; Tomkinson, Grant; Esterman, Adrian; English, Coralie; Lewis, Nicole; Olds, Tim

2012-10-08

The activitystat hypothesis proposes that when physical activity or energy expenditure is increased or decreased in one domain, there will be a compensatory change in another domain to maintain an overall, stable level of physical activity or energy expenditure. To date, there has been no experimental study primarily designed to test the activitystat hypothesis in adults. The aim of this trial is to determine the effect of two different imposed exercise loads on total daily energy expenditure and physical activity levels. This study will be a randomised, multi-arm, parallel controlled trial. Insufficiently active adults (as determined by the Active Australia survey) aged 18-60 years old will be recruited for this study (n=146). Participants must also satisfy the Sports Medicine Australia Pre-Exercise Screening System and must weigh less than 150 kg. Participants will be randomly assigned to one of three groups using a computer-generated allocation sequence. Participants in the Moderate exercise group will receive an additional 150 minutes of moderate to vigorous physical activity per week for six weeks, and those in the Extensive exercise group will receive an additional 300 minutes of moderate to vigorous physical activity per week for six weeks. Exercise targets will be accumulated through both group and individual exercise sessions monitored by heart rate telemetry. Control participants will not be given any instructions regarding lifestyle. The primary outcome measures are activity energy expenditure (doubly labeled water) and physical activity (accelerometry). Secondary measures will include resting metabolic rate via indirect calorimetry, use of time, maximal oxygen consumption and several anthropometric and physiological measures. Outcome measures will be conducted at baseline (zero weeks), mid- and end-intervention (three and six weeks) with three (12 weeks) and six month (24 week) follow-up. All assessors will be blinded to group allocation. This protocol has been specifically designed to test the activitystat hypothesis while taking into account the key conceptual and methodological considerations of testing a biologically regulated homeostatic feedback loop. Results of this study will be an important addition to the growing literature and debate concerning the possible existence of an activitystat. Australian New Zealand Clinical Trials Registry ACTRN12610000248066.

Testing the activitystat hypothesis: a randomised controlled trial protocol

PubMed Central

2012-01-01

Background The activitystat hypothesis proposes that when physical activity or energy expenditure is increased or decreased in one domain, there will be a compensatory change in another domain to maintain an overall, stable level of physical activity or energy expenditure. To date, there has been no experimental study primarily designed to test the activitystat hypothesis in adults. The aim of this trial is to determine the effect of two different imposed exercise loads on total daily energy expenditure and physical activity levels. Methods This study will be a randomised, multi-arm, parallel controlled trial. Insufficiently active adults (as determined by the Active Australia survey) aged 18–60 years old will be recruited for this study (n=146). Participants must also satisfy the Sports Medicine Australia Pre-Exercise Screening System and must weigh less than 150 kg. Participants will be randomly assigned to one of three groups using a computer-generated allocation sequence. Participants in the Moderate exercise group will receive an additional 150 minutes of moderate to vigorous physical activity per week for six weeks, and those in the Extensive exercise group will receive an additional 300 minutes of moderate to vigorous physical activity per week for six weeks. Exercise targets will be accumulated through both group and individual exercise sessions monitored by heart rate telemetry. Control participants will not be given any instructions regarding lifestyle. The primary outcome measures are activity energy expenditure (doubly labeled water) and physical activity (accelerometry). Secondary measures will include resting metabolic rate via indirect calorimetry, use of time, maximal oxygen consumption and several anthropometric and physiological measures. Outcome measures will be conducted at baseline (zero weeks), mid- and end-intervention (three and six weeks) with three (12 weeks) and six month (24 week) follow-up. All assessors will be blinded to group allocation. Discussion This protocol has been specifically designed to test the activitystat hypothesis while taking into account the key conceptual and methodological considerations of testing a biologically regulated homeostatic feedback loop. Results of this study will be an important addition to the growing literature and debate concerning the possible existence of an activitystat. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12610000248066 PMID:23043381

Unconscious semantic activation depends on feature-specific attention allocation.

PubMed

Spruyt, Adriaan; De Houwer, Jan; Everaert, Tom; Hermans, Dirk

2012-01-01

We examined whether semantic activation by subliminally presented stimuli is dependent upon the extent to which participants assign attention to specific semantic stimulus features and stimulus dimensions. Participants pronounced visible target words that were preceded by briefly presented, masked prime words. Both affective and non-affective semantic congruence of the prime-target pairs were manipulated under conditions that either promoted selective attention for affective stimulus information or selective attention for non-affective semantic stimulus information. In line with our predictions, results showed that affective congruence had a clear impact on word pronunciation latencies only if participants were encouraged to assign attention to the affective stimulus dimension. In contrast, non-affective semantic relatedness of the prime-target pairs produced no priming at all. Our findings are consistent with the hypothesis that unconscious activation of (affective) semantic information is modulated by feature-specific attention allocation. Copyright © 2011 Elsevier B.V. All rights reserved.

An analysis of stock market efficiency: Developed vs Islamic stock markets using MF-DFA

NASA Astrophysics Data System (ADS)

Rizvi, Syed Aun R.; Dewandaru, Ginanjar; Bacha, Obiyathulla I.; Masih, Mansur

An efficient market has been theoretically proven to be a key component for effective and efficient resource allocation in an economy. This paper incorporates econophysics with Efficient Market Hypothesis to undertake a comparative analysis of Islamic and developed countries’ markets by extending the understanding of their multifractal nature. By applying the Multifractal Detrended Fluctuation Analysis (MFDFA) we calculated the generalized Hurst exponents, multifractal scaling exponents and generalized multifractal dimensions for 22 broad market indices. The findings provide a deeper understanding of the markets in Islamic countries, where they have traces of highly efficient performance particularly in crisis periods. A key finding is the empirical evidence of the impact of the ‘stage of market development’ on the efficiency of the market. If Islamic countries aim to improve the efficiency of resource allocation, an important area to address is to focus, among others, on enhancing the stage of market development.

Sorting Citizens: Differentiated Citizenship Education in Singapore

ERIC Educational Resources Information Center

Ho, Li-Ching

2012-01-01

Using Singapore as a case study, this paper examines how the discourses of democratic elitism and meritocracy help allocate different citizen roles to students and define the nature of the social studies citizenship education programmes for different educational tracks. While the Singapore education system is not unique in its stratification of…

General Child Benefit Fund Experiments in Providing Differentiated Services

ERIC Educational Resources Information Center

Serres, Anne-Marie

2005-01-01

Populations not autonomous in their administrative relations has difficulties with access to social benefits of the Caisses d'Allocations Familiales (CAFs). These difficulties, whether rooted in cultural, educational, social, or other issues, disrupt the management of their documents of social benefits and thereby weigh on their economic…

The mental representation of living and nonliving things: differential weighting and interactivity of sensorial and non-sensorial features.

PubMed

Ventura, Paulo; Morais, José; Brito-Mendes, Carlos; Kolinsky, Régine

2005-02-01

Warrington and colleagues (Warrington & McCarthy, 1983, 1987; Warrington & Shallice, 1984) claimed that sensorial and functional-associative (FA) features are differentially important in determining the meaning of living things (LT) and nonliving things (NLT). The first aim of the present study was to evaluate this hypothesis through two different access tasks: feature generation (Experiment 1) and cued recall (Experiment 2). The results of both experiments provided consistent empirical support for Warrington and colleagues' assumption. The second aim of the present study was to test a new differential interactivity hypothesis that combines Warrington and colleagueS' assumption with the notion of a higher number of intercorrelations and hence of a stronger connectivity between sensorial and non-sensorial features for LTs than for NLTs. This hypothesis was motivated by previoUs reports of an uncrossed interaction between domain (LTs vs NLTs) and attribute type (sensorial vs FA) in, for example, a feature verification task (Laws, Humber, Ramsey, & McCarthy, 1995): while FA attributes are verified faster than sensorial attributes for NLTs, no difference is observed for LTs. We replicated and generalised this finding using several feature verification tasks on both written words and pictures (Experiment 3), including in conditions aimed at minimising the intervention of priming biases and strategic or mnemonic processes (Experiment 4). The whole set of results suggests that both privileged relations between features and categories, and the differential importance of intercorrelations between features as a function of category, modulate access to semantic features.

Visibility vs. biomass in flowers: exploring corolla allocation in Mediterranean entomophilous plants

PubMed Central

Herrera, Javier

2009-01-01

Background and Aims While pollinators may in general select for large, morphologically uniform floral phenotypes, drought stress has been proposed as a destabilizing force that may favour small flowers and/or promote floral variation within species. Methods The general validity of this concept was checked by surveying a taxonomically diverse array of 38 insect-pollinated Mediterranean species. The interplay between fresh biomass investment, linear size and percentage corolla allocation was studied. Allometric relationships between traits were investigated by reduced major-axis regression, and qualitative correlates of floral variation explored using general linear-model MANOVA. Key Results Across species, flowers were perfectly isometrical with regard to corolla allocation (i.e. larger flowers were just scaled-up versions of smaller ones and vice versa). In contrast, linear size and biomass varied allometrically (i.e. there were shape variations, in addition to variations in size). Most floral variables correlated positively and significantly across species, except corolla allocation, which was largely determined by family membership and floral symmetry. On average, species with bilateral flowers allocated more to the corolla than those with radial flowers. Plant life-form was immaterial to all of the studied traits. Flower linear size variation was in general low among conspecifics (coefficients of variation around 10 %), whereas biomass was in general less uniform (e.g. 200–400 mg in Cistus salvifolius). Significant among-population differences were detected for all major quantitative floral traits. Conclusions Flower miniaturization can allow an improved use of reproductive resources under prevailingly stressful conditions. The hypothesis that flower size reflects a compromise between pollinator attraction, water requirements and allometric constraints among floral parts is discussed. PMID:19258340

Male Snakes Allocate Time and Energy according to Individual Energetic Status: Body Condition, Steroid Hormones, and Reproductive Behavior in Timber Rattlesnakes, Crotalus horridus.

PubMed

Lind, Craig M; Beaupre, Steven J

2015-01-01

Life-history theory predicts that organisms will hedge current reproductive investment against potential costs in terms of survivorship and future fecundity. However, little is known regarding the endocrine mechanisms underlying bet-hedging strategies in free-ranging male vertebrates. We examined the relationships among individual energetic status, steroid hormones, mate search, and reproductive behavior in free-ranging male timber rattlesnakes. Snakes were monitored over four active seasons in order to test two hypotheses: (1) males adjust the amount of time and energy allocated toward reproduction according to the level of individual energy stores, and (2) observed condition-dependent reproductive allocation is associated with circulating concentrations of steroid hormones (testosterone and corticosterone) thought to regulate reproductive behaviors in vertebrates. A positive relationship between body condition and testosterone was observed in both the field and the laboratory. Male mate search effort was positively correlated with both body condition and testosterone. Body condition and testosterone concentrations were negatively related to time allocated toward foraging during the breeding season. A strong effect of year was observed in the analysis of testosterone and search effort, suggesting that multiple environmental factors impact hormone production and reproductive investment. Corticosterone was not related to any measured variable. Therefore, our results did not indicate a clear role of corticosterone in mediating observed relationships between energetic status and behavior. Observed relationships are consistent with the hypothesis that males allocate time and energy toward reproduction according to individual energetic status and that testosterone plays a role in mediating the trade-off between current reproductive investment and residual reproductive value.

Meta-Analysis of Multiple Simulation-Based Experiments

DTIC Science & Technology

2013-06-01

Alberts et al ., 2010), C2 Approaches differ on at least three major aspects: the allocation of decision rights (ADR), the pattern of interaction among...results obtained from the meta-analysis support the hypothesis that more network-enabled C2 Approaches are more agile (for details see Bernier et al ...consult Bernier, Chan et al . (2013) for more details. DoI PoI ADR Figure 2: Mapping of all CiCs into each axis of the C2 Approach Space. 18th

Multi-Tiered System of Support: Best Differentiation Practices for English Language Learners in Tier 1

ERIC Educational Resources Information Center

Izaguirre, Cecilia

2017-01-01

Purpose: This qualitative case study explored the best practices of differentiation of Tier 1 instruction within a multi-tiered system of support for English Language Learners who were predominately Spanish speaking. Theoretical Framework: The zone of proximal development theory, cognitive theory, and the affective filter hypothesis guided this…

Goal Direction and Effectiveness, Emotional Maturity, and Nuclear Family Functioning

ERIC Educational Resources Information Center

Klever, Phillip

2009-01-01

Differentiation of self, a cornerstone concept in Bowen theory, has a profound influence over time on the functioning of the individual and his or her family unit. This 5-year longitudinal study tested this hypothesis with 50 developing nuclear families. The dimensions of differentiation of self that were examined were goal direction and…

Why Classroom Climate Matters for Children High in Anxious Solitude: A Study of Differential Susceptibility

ERIC Educational Resources Information Center

Hughes, Kathleen; Coplan, Robert J.

2018-01-01

The goal of the current study was to examine the complex links among anxious solitude, classroom climate, engagement, achievement, and gender. In particular, drawing upon the differential susceptibility hypothesis (Belsky, 1997), we investigated if children high in anxious solitude were particularly sensitive and responsive to the classroom…

Child Differential Sensitivity to Parental Self-Efficacy Improvement: A Micro-Trial Perspective

ERIC Educational Resources Information Center

Mouton, Bénédicte; Loop, Laurie; Stievenart, Marie; Roskam, Isabelle

2018-01-01

This study investigates the hypothesis of a child differential sensitivity to parenting improvement. One hundred and fourteen parents of preschoolers participated in two parenting micro-trials aiming to increase parental self-efficacy in view of improving child behavior. The first micro-trial took place in a short-term laboratory experiment; the…

Differentiation of Cognitive Abilities as a Function of Neuroticism Level: A Measurement Equivalence/Invariance Analysis

ERIC Educational Resources Information Center

Bonaccio, Silvia; Reeve, Charlie L.

2006-01-01

This paper investigates the differentiation of cognitive abilities as a function of neuroticism. Specifically, we examine Eysenck and White's [Eysenck, H. J., and White, P. O. (1964). Personality and the measurement of intelligence. British Journal of Educational Psychology, 24, 197-201.] hypothesis that cognitive abilities are less differentiated…

Quantification of differential gene expression by multiplexed targeted resequencing of cDNA

PubMed Central

Arts, Peer; van der Raadt, Jori; van Gestel, Sebastianus H.C.; Steehouwer, Marloes; Shendure, Jay; Hoischen, Alexander; Albers, Cornelis A.

2017-01-01

Whole-transcriptome or RNA sequencing (RNA-Seq) is a powerful and versatile tool for functional analysis of different types of RNA molecules, but sample reagent and sequencing cost can be prohibitive for hypothesis-driven studies where the aim is to quantify differential expression of a limited number of genes. Here we present an approach for quantification of differential mRNA expression by targeted resequencing of complementary DNA using single-molecule molecular inversion probes (cDNA-smMIPs) that enable highly multiplexed resequencing of cDNA target regions of ∼100 nucleotides and counting of individual molecules. We show that accurate estimates of differential expression can be obtained from molecule counts for hundreds of smMIPs per reaction and that smMIPs are also suitable for quantification of relative gene expression and allele-specific expression. Compared with low-coverage RNA-Seq and a hybridization-based targeted RNA-Seq method, cDNA-smMIPs are a cost-effective high-throughput tool for hypothesis-driven expression analysis in large numbers of genes (10 to 500) and samples (hundreds to thousands). PMID:28474677

Human actuarial aging increases faster when back ground death rates are lower: a consequence of differential heterogeneity?

PubMed Central

Hawkes, Kristen; Smith, Ken R.; Blevins, James K.

2014-01-01

Many analyses of human populations have found that age-specific mortality rates increase faster across most of adulthood when overall mortality levels decline. This contradicts the relationship often expected from Williams′ classic hypothesis about the effects of natural selection on the evolution of senescence. More likely, much of the within-species difference in actuarial aging is not due to variation in senescence, but to the strength of filters on the heterogeneity of frailty in older survivors. A challenge to this differential frailty hypothesis was recently posed by an analysis of life tables from historical European populations and traditional societies that reported variation in actuarial aging consistent with Williams′ hypothesis after all. To investigate the challenge, we reconsidered those cases and aging measures. Here we show that the discrepancy depends on Ricklefs′ aging rate measure,ω, which decreases as mortality levels drop because it is an index of mortality level itself, not the rate of increase in mortality with age. We also show unappreciated correspondence among the parameters of Gompertz–Makeham and Weibull survival models. Finally, we compare the relationships among mortality parameters of the traditional societies and the historical series, providing further suggestive evidence that differential heterogeneity has strong effects on actuarial aging. PMID:22220868

Influence of mate preference and laying order on maternal allocation in a monogamous parrot species with extreme hatching asynchrony.

PubMed

Lahaye, Stefanie E P; Eens, Marcel; Iserbyt, Arne; Groothuis, Ton G G; de Vries, Bonnie; Müller, Wendt; Pinxten, Rianne

2015-05-01

It is well established that in many avian species, prenatal maternal resource allocation varies both between and within clutches and may affect offspring fitness. Differential allocation of maternal resources, in terms of egg weight and yolk composition, may therefore allow the female to adjust brood reduction and to fine-tune reproductive investment in accordance with the expected fitness returns. The adaptive value of such maternal resource allocation is thought to be context-dependent as well as species-specific. We investigated the effects of female preference for her mate on the allocation of prenatal maternal resources in the budgerigar, Melopsittacus undulatus, a monogamous species of parrot that shows an extreme hatching asynchrony. We assessed mate preferences in a two-way preference test and allowed females two breeding rounds: one with the preferred and one with the non-preferred partner. We found no effect of preference on either latency to lay or clutch size, but females mated with the preferred partner laid eggs that contained significantly more yolk. Their eggs also contained significantly more androstenedione but not testosterone. Our results suggest that in this species, female preference may influence maternal resource allocation, and that the functional roles of each androgen in the yolk should be considered separately. In addition, we found a significant effect of laying order on egg and yolk weight as well as on yolk testosterone and androstenedione levels. These measures, however, did not change linearly with the laying order and render it unlikely that female budgerigars compensate for the extreme hatching asynchrony by adjusting within-clutch allocation of prenatal maternal resources. Copyright © 2015 Elsevier Inc. All rights reserved.

Pancreas lineage allocation and specification are regulated by sphingosine-1-phosphate signalling.

PubMed

Serafimidis, Ioannis; Rodriguez-Aznar, Eva; Lesche, Mathias; Yoshioka, Kazuaki; Takuwa, Yoh; Dahl, Andreas; Pan, Duojia; Gavalas, Anthony

2017-03-01

During development, progenitor expansion, lineage allocation, and implementation of differentiation programs need to be tightly coordinated so that different cell types are generated in the correct numbers for appropriate tissue size and function. Pancreatic dysfunction results in some of the most debilitating and fatal diseases, including pancreatic cancer and diabetes. Several transcription factors regulating pancreas lineage specification have been identified, and Notch signalling has been implicated in lineage allocation, but it remains unclear how these processes are coordinated. Using a combination of genetic approaches, organotypic cultures of embryonic pancreata, and genomics, we found that sphingosine-1-phosphate (S1p), signalling through the G protein coupled receptor (GPCR) S1pr2, plays a key role in pancreas development linking lineage allocation and specification. S1pr2 signalling promotes progenitor survival as well as acinar and endocrine specification. S1pr2-mediated stabilisation of the yes-associated protein (YAP) is essential for endocrine specification, thus linking a regulator of progenitor growth with specification. YAP stabilisation and endocrine cell specification rely on Gαi subunits, revealing an unexpected specificity of selected GPCR intracellular signalling components. Finally, we found that S1pr2 signalling posttranscriptionally attenuates Notch signalling levels, thus regulating lineage allocation. Both S1pr2-mediated YAP stabilisation and Notch attenuation are necessary for the specification of the endocrine lineage. These findings identify S1p signalling as a novel key pathway coordinating cell survival, lineage allocation, and specification and linking these processes by regulating YAP levels and Notch signalling. Understanding lineage allocation and specification in the pancreas will shed light in the origins of pancreatic diseases and may suggest novel therapeutic approaches.

Pancreas lineage allocation and specification are regulated by sphingosine-1-phosphate signalling

PubMed Central

Serafimidis, Ioannis; Rodriguez-Aznar, Eva; Lesche, Mathias; Yoshioka, Kazuaki; Takuwa, Yoh; Dahl, Andreas; Pan, Duojia; Gavalas, Anthony

2017-01-01

During development, progenitor expansion, lineage allocation, and implementation of differentiation programs need to be tightly coordinated so that different cell types are generated in the correct numbers for appropriate tissue size and function. Pancreatic dysfunction results in some of the most debilitating and fatal diseases, including pancreatic cancer and diabetes. Several transcription factors regulating pancreas lineage specification have been identified, and Notch signalling has been implicated in lineage allocation, but it remains unclear how these processes are coordinated. Using a combination of genetic approaches, organotypic cultures of embryonic pancreata, and genomics, we found that sphingosine-1-phosphate (S1p), signalling through the G protein coupled receptor (GPCR) S1pr2, plays a key role in pancreas development linking lineage allocation and specification. S1pr2 signalling promotes progenitor survival as well as acinar and endocrine specification. S1pr2-mediated stabilisation of the yes-associated protein (YAP) is essential for endocrine specification, thus linking a regulator of progenitor growth with specification. YAP stabilisation and endocrine cell specification rely on Gαi subunits, revealing an unexpected specificity of selected GPCR intracellular signalling components. Finally, we found that S1pr2 signalling posttranscriptionally attenuates Notch signalling levels, thus regulating lineage allocation. Both S1pr2-mediated YAP stabilisation and Notch attenuation are necessary for the specification of the endocrine lineage. These findings identify S1p signalling as a novel key pathway coordinating cell survival, lineage allocation, and specification and linking these processes by regulating YAP levels and Notch signalling. Understanding lineage allocation and specification in the pancreas will shed light in the origins of pancreatic diseases and may suggest novel therapeutic approaches. PMID:28248965

The Kidney Donor Profile Index (KDPI) of Marginal Donors Allocated by Standardized Pre-Transplant Donor Biopsy Assessment: Distribution and Association with Graft Outcomes

PubMed Central

Gandolfini, I.; Buzio, C.; Zanelli, P.; Palmisano, A.; Cremaschi, E.; Vaglio, A.; Piotti, G.; Melfa, L.; La Manna, G.; Feliciangeli, G.; Cappuccilli, M.; Scolari, M.P.; Capelli, I.; Panicali, L.; Baraldi, O.; Stefoni, S.; Buscaroli, A.; Ridolfi, L.; D'Errico, A.; Cappelli, G.; Bonucchi, D.; Rubbiani, E.; Albertazzi, A.; Mehrotra, A.; Cravedi, P.; Maggiore, U.

2015-01-01

Pre-transplant donor biopsy (PTDB)-based marginal-donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the US. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score <4 [median KDPI:87; interquartile range(IQR):78-94] and 62 with a score =4 [median KDPI:87; IQR:76-93]; 102 dual transplants [median KDPI: 93; IQR:86-96]) and 248 single standard transplant controls [median KDPI:36; IQR:18-51]. PTDB-based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80-90 and of 37% for kidneys with a KDPI of 91-100. Although 1-year eGFRs were significantly lower in recipients of marginal kidneys (-9.3, -17.9, and -18.8ml/min, for dual transplants, single kidneys with PTDB score <4, and =4, respectively; P<0.001), graft survival (median follow-up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80 to 1.79; P=0.38]). In conclusion, PTDB-based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded. PMID:25155294

Optimal Power Allocation Strategy in a Joint Bistatic Radar and Communication System Based on Low Probability of Intercept

PubMed Central

Wang, Fei; Salous, Sana; Zhou, Jianjiang

2017-01-01

In this paper, we investigate a low probability of intercept (LPI)-based optimal power allocation strategy for a joint bistatic radar and communication system, which is composed of a dedicated transmitter, a radar receiver, and a communication receiver. The joint system is capable of fulfilling the requirements of both radar and communications simultaneously. First, assuming that the signal-to-noise ratio (SNR) corresponding to the target surveillance path is much weaker than that corresponding to the line of sight path at radar receiver, the analytically closed-form expression for the probability of false alarm is calculated, whereas the closed-form expression for the probability of detection is not analytically tractable and is approximated due to the fact that the received signals are not zero-mean Gaussian under target presence hypothesis. Then, an LPI-based optimal power allocation strategy is presented to minimize the total transmission power for information signal and radar waveform, which is constrained by a specified information rate for the communication receiver and the desired probabilities of detection and false alarm for the radar receiver. The well-known bisection search method is employed to solve the resulting constrained optimization problem. Finally, numerical simulations are provided to reveal the effects of several system parameters on the power allocation results. It is also demonstrated that the LPI performance of the joint bistatic radar and communication system can be markedly improved by utilizing the proposed scheme. PMID:29186850

Optimal Power Allocation Strategy in a Joint Bistatic Radar and Communication System Based on Low Probability of Intercept.

PubMed

Shi, Chenguang; Wang, Fei; Salous, Sana; Zhou, Jianjiang

2017-11-25

In this paper, we investigate a low probability of intercept (LPI)-based optimal power allocation strategy for a joint bistatic radar and communication system, which is composed of a dedicated transmitter, a radar receiver, and a communication receiver. The joint system is capable of fulfilling the requirements of both radar and communications simultaneously. First, assuming that the signal-to-noise ratio (SNR) corresponding to the target surveillance path is much weaker than that corresponding to the line of sight path at radar receiver, the analytically closed-form expression for the probability of false alarm is calculated, whereas the closed-form expression for the probability of detection is not analytically tractable and is approximated due to the fact that the received signals are not zero-mean Gaussian under target presence hypothesis. Then, an LPI-based optimal power allocation strategy is presented to minimize the total transmission power for information signal and radar waveform, which is constrained by a specified information rate for the communication receiver and the desired probabilities of detection and false alarm for the radar receiver. The well-known bisection search method is employed to solve the resulting constrained optimization problem. Finally, numerical simulations are provided to reveal the effects of several system parameters on the power allocation results. It is also demonstrated that the LPI performance of the joint bistatic radar and communication system can be markedly improved by utilizing the proposed scheme.

Function allocation for humans and automation in the context of team dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeffrey C. Joe; John O'Hara; Jacques Hugo

Within Human Factors Engineering, a decision-making process called function allocation (FA) is used during the design life cycle of complex systems to distribute the system functions, often identified through a functional requirements analysis, to all human and automated machine agents (or teammates) involved in controlling the system. Most FA methods make allocation decisions primarily by comparing the capabilities of humans and automation, but then also by considering secondary factors such as cost, regulations, and the health and safety of workers. The primary analysis of the strengths and weaknesses of humans and machines, however, is almost always considered in terms ofmore » individual human or machine capabilities. Yet, FA is fundamentally about teamwork in that the goal of the FA decision-making process is to determine what are the optimal allocations of functions among agents. Given this framing of FA, and the increasing use of and sophistication of automation, there are two related social psychological issues that current FA methods need to address more thoroughly. First, many principles for effective human teamwork are not considered as central decision points or in the iterative hypothesis and testing phase in most FA methods, when it is clear that social factors have numerous positive and negative effects on individual and team capabilities. Second, social psychological factors affecting team performance and can be difficult to translate to automated agents, and most FA methods currently do not account for this effect. The implications for these issues are discussed.« less

Gendered depression: Vulnerability or exposure to work and family stressors?

PubMed

Marchand, Alain; Bilodeau, Jaunathan; Demers, Andrée; Beauregard, Nancy; Durand, Pierre; Haines, Victor Y

2016-10-01

Research has shown that employed women are more prone to depression than men, but the pathways linking gender to depression remain poorly understood. The aim of this study was to examine how work and family conditions operated as potentially gendered antecedents of depression. It evaluated more specifically how differences in depressive symptoms in women and men could be explained by their differential vulnerability and exposure to work and family conditions, as well as by the mediating role of work-to-family conflict (WFC) and family-to-work conflict (FWC). Data were collected in 2009-2012 from a sample of 1935 employees (48.9% women) nested in 63 workplaces in the province of Quebec (Canada). Data were analyzed with multilevel path analysis models to test for the differential exposure hypothesis, and stratified by gender to test for the differential vulnerability hypothesis. Results supported both hypothesizes, but only WFC played a mediating role between work-family stressors and depression. Regarding the vulnerability hypothesis, WFC was more strongly associated with women depressive symptoms, and the magnitude of the association between family income and WFC was stronger for women. Overall, the differential exposure hypothesis seemed to reach a greater empirical support. After accounting for work and family stressors as well as WFC, differences in depressive symptoms in women and men were no longer significantly, as WFC, working hours, irregular work schedule and skill utilization acted as mediators. WFC associated with higher depressive symptoms and skill utilization with lower depressive symptoms. WFC related to higher working hours and irregular work schedule. Compared to men, women reported higher WFC, but lower working hours, less irregular work schedule and lower skill utilization at work. Women's higher rate of depression is intrinsically linked to their different social experiences as shaped by a gendered social structure and gendered organizations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visual selective attention is equally functional for individuals with low and high working memory capacity: evidence from accuracy and eye movements.

PubMed

Mall, Jonathan T; Morey, Candice C; Wolff, Michael J; Lehnert, Franziska

2014-10-01

Selective attention and working memory capacity (WMC) are related constructs, but debate about the manner in which they are related remains active. One elegant explanation of variance in WMC is that the efficiency of filtering irrelevant information is the crucial determining factor, rather than differences in capacity per se. We examined this hypothesis by relating WMC (as measured by complex span tasks) to accuracy and eye movements during visual change detection tasks with different degrees of attentional filtering and allocation requirements. Our results did not indicate strong filtering differences between high- and low-WMC groups, and where differences were observed, they were counter to those predicted by the strongest attentional filtering hypothesis. Bayes factors indicated evidence favoring positive or null relationships between WMC and correct responses to unemphasized information, as well as between WMC and the time spent looking at unemphasized information. These findings are consistent with the hypothesis that individual differences in storage capacity, not only filtering efficiency, underlie individual differences in working memory.

Influence of microgravity on cellular differentiation in root caps of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; Fondren, W. M.; McClelen, C. E.; Wang, C. L.

1987-01-01

We launched imbibed seeds of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on cellular differentiation in root caps. The influence of microgravity varied with different stages of cellular differentiation. Overall, microgravity tended to 1) increase relative volumes of hyaloplasm and lipid bodies, 2) decrease the relative volumes of plastids, mitochondria, dictyosomes, and the vacuome, and 3) exert no influence on the relative volume of nuclei in cells comprising the root cap. The reduced allocation of dictyosomal volume in peripheral cells of flight-grown seedlings correlated positively with their secretion of significantly less mucilage than peripheral cells of Earth-grown seedlings. These results indicate that 1) microgravity alters the patterns of cellular differentiation and structures of all cell types comprising the root cap, and 2) the influence of microgravity on cellular differentiation in root caps of Zea mays is organelle specific.

Differential Allocation to Photosynthetic and Non-Photosynthetic Nitrogen Fractions among Native and Invasive Species

PubMed Central

Funk, Jennifer L.; Glenwinkel, Lori A.; Sack, Lawren

2013-01-01

Invasive species are expected to cluster on the “high-return” end of the leaf economic spectrum, displaying leaf traits consistent with higher carbon assimilation relative to native species. Intra-leaf nitrogen (N) allocation should support these physiological differences; however, N biochemistry has not been examined in more than a few invasive species. We measured 34 leaf traits including seven leaf N pools for five native and five invasive species from Hawaii under low irradiance to mimic the forest understory environment. We found several trait differences between native and invasive species. In particular, invasive species showed preferential N allocation to metabolism (amino acids) rather than photosynthetic light reactions (membrane-bound protein) by comparison with native species. The soluble protein concentration did not vary between groups. Under these low irradiance conditions, native species had higher light-saturated photosynthetic rates, possibly as a consequence of a greater investment in membrane-bound protein. Invasive species may succeed by employing a wide range of N allocation mechanisms, including higher amino acid production for fast growth under high irradiance or storage of N in leaves as soluble protein or amino acids. PMID:23700483

Cerebral hemovelocity reveals differential resource allocation strategies for extraverts and introverts during vigilance.

PubMed

Shaw, Tyler H; Nguyen, Cynthia; Satterfield, Kelly; Ramirez, Raul; McKnight, Patrick E

2016-02-01

Extraversion--one of the Big 5 personality factors--correlates negatively with vigilance, but most studies focus on performance outcomes and not the performance process. Previous research has shown that transcranial Doppler sonography (TCD), which measures cerebral blood flow velocity (CBFV), can be used to examine resource allocation strategies during vigilance performance. Hence, this study was designed to assess the attentional resource allocation strategies of introverts and extraverts using the CBFV measure. Twelve extroverts and 13 introverts monitored a 60-min vigilance task for a critical signal--the absence of a line on a five-circle array. The results revealed an overall performance decrement that was not modulated by extraversion. We observed an interaction between extraversion and time; CBFV declined in the introversion group, but not in the extraversion group. Additionally, an interaction between cerebral hemisphere and personality revealed that extraverts were recruiting resources from both the left and right cerebral hemispheres, while introverts only recruited resources from the right hemisphere. The results suggest that extraverts can allocate compensatory effort to mask performance differences. We discuss the theoretical and practical implications of these findings and offer future research directions that may help us understand these effects.

The Evolution of Autistic-Like and Schizotypal Traits: A Sexual Selection Hypothesis

PubMed Central

Del Giudice, Marco; Angeleri, Romina; Brizio, Adelina; Elena, Marco R.

2010-01-01

In this paper we present a new hypothesis on the evolution of autistic-like and schizotypal personality traits. We argue that autistic-like and schizotypal traits contribute in opposite ways to individual differences in reproductive and mating strategies, and have been maintained – at least in part – by sexual selection through mate choice. Whereas positive schizotypy can be seen as a psychological phenotype oriented to high-mating effort and good genes displays in both sexes, autistic-like traits in their non-pathological form contribute to a male-typical strategy geared toward high parental investment, low-mating effort, and long-term resource allocation. At the evolutionary-genetic level, this sexual selection hypothesis is consistent with Crespi and Badcock's “imprinted brain” theory of autism and psychosis; the effect of offspring mating behavior on resource flow within the family connects sexual selection with genomic imprinting in the context of human biparental care. We conclude by presenting the results of an empirical study testing one of the predictions derived from our hypothesis. In a sample of 199 college students, autistic-like traits predicted lower interest in short-term mating, higher partner-specific investment, and stronger commitment to long-term romantic relations, whereas positive schizotypy showed the opposite pattern of effects. PMID:21833210

Conservativeness in Rejection of the Null Hypothesis when Using the Continuity Correction in the MH Chi-Square Test in DIF Applications

ERIC Educational Resources Information Center

Paek, Insu

2010-01-01

Conservative bias in rejection of a null hypothesis from using the continuity correction in the Mantel-Haenszel (MH) procedure was examined through simulation in a differential item functioning (DIF) investigation context in which statistical testing uses a prespecified level [alpha] for the decision on an item with respect to DIF. The standard MH…

Evaluating sample allocation and effort in detecting population differentiation for discrete and continuously distributed individuals

Treesearch

Erin L. Landguth; Michael K. Schwartz

2014-01-01

One of the most pressing issues in spatial genetics concerns sampling. Traditionally, substructure and gene flow are estimated for individuals sampled within discrete populations. Because many species may be continuously distributed across a landscape without discrete boundaries, understanding sampling issues becomes paramount. Given large-scale, geographically broad...

Environmental Effects on Constitutive and Inducible Resin Defences of Pinus taeda

Treesearch

Maria L. Lombardero; Matthew P. Ayres; Peter L. Lorio; Jonathan J. Ruel

2000-01-01

The ecological literature abounds with studies of environmental effects on plant antiherbivore defences. While various models have been proposed (e.g. plant stress, optimal allocation, growth-differentiation balance), each has met with mixed support. One possible explanation for the mixed results is that constitutive and induced defences are differentialiy affected by...

Algorithms for synthesizing management solutions based on OLAP-technologies

NASA Astrophysics Data System (ADS)

Pishchukhin, A. M.; Akhmedyanova, G. F.

2018-05-01

OLAP technologies are a convenient means of analyzing large amounts of information. An attempt was made in their work to improve the synthesis of optimal management decisions. The developed algorithms allow forecasting the needs and accepted management decisions on the main types of the enterprise resources. Their advantage is the efficiency, based on the simplicity of quadratic functions and differential equations of only the first order. At the same time, the optimal redistribution of resources between different types of products from the assortment of the enterprise is carried out, and the optimal allocation of allocated resources in time. The proposed solutions can be placed on additional specially entered coordinates of the hypercube representing the data warehouse.

Modeling evolution of the mind and cultures: emotional Sapir-Whorf hypothesis

NASA Astrophysics Data System (ADS)

Perlovsky, Leonid I.

2009-05-01

Evolution of cultures is ultimately determined by mechanisms of the human mind. The paper discusses the mechanisms of evolution of language from primordial undifferentiated animal cries to contemporary conceptual contents. In parallel with differentiation of conceptual contents, the conceptual contents were differentiated from emotional contents of languages. The paper suggests the neural brain mechanisms involved in these processes. Experimental evidence and theoretical arguments are discussed, including mathematical approaches to cognition and language: modeling fields theory, the knowledge instinct, and the dual model connecting language and cognition. Mathematical results are related to cognitive science, linguistics, and psychology. The paper gives an initial mathematical formulation and mean-field equations for the hierarchical dynamics of both the human mind and culture. In the mind heterarchy operation of the knowledge instinct manifests through mechanisms of differentiation and synthesis. The emotional contents of language are related to language grammar. The conclusion is an emotional version of Sapir-Whorf hypothesis. Cultural advantages of "conceptual" pragmatic cultures, in which emotionality of language is diminished and differentiation overtakes synthesis resulting in fast evolution at the price of self doubts and internal crises are compared to those of traditional cultures where differentiation lags behind synthesis, resulting in cultural stability at the price of stagnation. Multi-language, multi-ethnic society might combine the benefits of stability and fast differentiation. Unsolved problems and future theoretical and experimental directions are discussed.

The Substrata-Factor Theory of Reading: Differential Development of Subsystems Underlying Reading Comprehension in the First Year of Instruction.

ERIC Educational Resources Information Center

Katz, Ina; Singer, Harry

A study tested the instructional hypothesis that variation in instructional methods in the initial stages of formal reading development will differentially develop subsystems for attaining comprehension. The 91 kindergarten and first grade students in the study received their usual reading instruction plus supplementary instruction in one of four…

Differential Susceptibility to Effects of the Home Environment on Motor Developmental Outcomes of Preschool Children: Low Birthweight Status as a Susceptibility Factor

ERIC Educational Resources Information Center

Wu, Jennifer Chun-Li; Chiang, Tung-liang

2016-01-01

Low birthweight (LBW) children tend to have higher risks of developmental problems. According to differential susceptibility hypothesis, these putatively vulnerable children may also disproportionately benefit from positive environmental exposure. This study aimed to examine whether LBW status moderates home environmental influences on…

A Novel Differential Susceptibility Gene: "CHRNA4" and Moderation of the Effect of Maltreatment on Child Personality

ERIC Educational Resources Information Center

Grazioplene, Rachael G.; DeYoung, Colin G.; Rogosch, Fred A.; Cicchetti, Dante

2013-01-01

Background: The differential susceptibility hypothesis states that some genetic variants that confer risk in adverse environments are beneficial in normal or nurturing environments. The cholinergic system is promising as a source of susceptibility genes because of its involvement in learning and neural plasticity. The cholinergic receptor gene…

The role of physical formidability in human social status allocation.

PubMed

Lukaszewski, Aaron W; Simmons, Zachary L; Anderson, Cameron; Roney, James R

2016-03-01

Why are physically formidable men willingly allocated higher social status by others in cooperative groups? Ancestrally, physically formidable males would have been differentially equipped to generate benefits for groups by providing leadership services of within-group enforcement (e.g., implementing punishment of free riders) and between-group representation (e.g., negotiating with other coalitions). Therefore, we hypothesize that adaptations for social status allocation are designed to interpret men's physical formidability as a cue to these leadership abilities, and to allocate greater status to formidable men on this basis. These hypotheses were supported in 4 empirical studies wherein young adults rated standardized photos of subjects (targets) who were described as being part of a white-collar business consultancy. In Studies 1 and 2, male targets' physical strength positively predicted ratings of their projected status within the organization, and this effect was mediated by perceptions that stronger men possessed greater leadership abilities of within-group enforcement and between-group representation. Moreover, (a) these same patterns held whether status was conceptualized as overall ascendancy, prestige-based status, or dominance-based status, and (b) strong men who were perceived as aggressively self-interested were not allocated greater status. Finally, 2 experiments established the causality of physical formidability's effects on status-related perceptions by manipulating targets' relative strength (Study 3) and height (Study 4). In interpreting our findings, we argue that adaptations for formidability-based status allocation may have facilitated the evolution of group cooperation in humans and other primates. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Interplay of wavelength, fluence and spot-size in free-electron laser ablation of cornea.

PubMed

Hutson, M Shane; Ivanov, Borislav; Jayasinghe, Aroshan; Adunas, Gilma; Xiao, Yaowu; Guo, Mingsheng; Kozub, John

2009-06-08

Infrared free-electron lasers ablate tissue with high efficiency and low collateral damage when tuned to the 6-microm range. This wavelength-dependence has been hypothesized to arise from a multi-step process following differential absorption by tissue water and proteins. Here, we test this hypothesis at wavelengths for which cornea has matching overall absorption, but drastically different differential absorption. We measure etch depth, collateral damage and plume images and find that the hypothesis is not confirmed. We do find larger etch depths for larger spot sizes--an effect that can lead to an apparent wavelength dependence. Plume imaging at several wavelengths and spot sizes suggests that this effect is due to increased post-pulse ablation at larger spots.

Carbon allocation to growth and storage in two evergreen species of contrasting successional status.

PubMed

Piper, Frida I; Sepúlveda, Paulina; Bustos-Salazar, Angela; Zúñiga-Feest, Alejandra

2017-05-01

A prevailing hypothesis in forest succession is that shade-tolerant species grow more slowly than shade-intolerant species, across light conditions, because they prioritize carbon (C) allocation to storage. We examined this hypothesis in a confamilial pair of species, including one of the fastest-growing tree species in the world ( Eucalyptus globulus ) and a shade-tolerant, slow-growing species ( Luma apiculata ). Seedlings were subjected to one out of four combinations of light (high vs. low) and initial defoliation (90% defoliated vs. nondefoliated) for four months. Growth, C storage concentration in different organs, leaf shedding, and lateral shoot formation were measured at the end of the experiment. Eucalyptus globulus grew faster than L. apiculata in high light, but not in low light. Both species had lower C storage concentration in low than in high light, but similar C storage concentrations in each light condition. Defoliation had no effect on C storage, except in the case of the old leaves of both species, which showed lower C storage levels in response to defoliation. Across treatments, leaf shedding was 96% higher in E. globulus than in L. apiculata while, in contrast, lateral shoot formation was 87% higher in L. apiculata . In low light, E. globulus prioritized C storage instead of growth, whereas L. apiculata prioritized growth and lateral branching. Our results suggest that shade tolerance depends on efficient light capture rather than C conservation traits. © 2017 Botanical Society of America.

Plumage brightness as an indicator of parental care in northern cardinals

PubMed

Linville; Breitwisch; Schilling

1998-01-01

Good parent and differential allocation models predict relationships between degree of sexual ornamentation and parental care, but relatively few studies have tested these models. The northern cardinal, Cardinalis cardinalis, is a sexually dichromatic species in which both sexes are ornamented. Males have red plumage, and females have tan plumage with limited areas of red feathering. Cardinals were used to address the two models and determine whether plumage brightness signals level of parental care by both sexes. Absolute effort in feeding nestlings by males was not correlated with male breast plumage colour, but effort by females was positively correlated with female underwing plumage colour. Absolute feeding effort by females was also inversely related to brightness of the mate's breast colour. As a consequence, the proportion of a pair's total feedings provided by the male was positively correlated with male breast colour. Proportion of total feedings provided by the female was positively correlated with female wing colour. Feeding efforts (both per nest and per nestling) were correlated between mates, but birds did not mate assortatively in relation to colour. These results support the good parent hypothesis, suggesting colour brightness is a signal of parental care. The results also indicate that ornamentation of both members of the pair may be important determinants of relative efforts in provisioning nestlings by parent birds. Copyright 1998 The Association for the Study of Animal Behaviour.

Congestion Pricing for Aircraft Pushback Slot Allocation.

PubMed

Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Congestion Pricing for Aircraft Pushback Slot Allocation

PubMed Central

Zhang, Yaping

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

Integration of vehicle yaw stabilisation and rollover prevention through nonlinear hierarchical control allocation

NASA Astrophysics Data System (ADS)

Alberding, Matthäus B.; Tjønnås, Johannes; Johansen, Tor A.

2014-12-01

This work presents an approach to rollover prevention that takes advantage of the modular structure and optimisation properties of the control allocation paradigm. It eliminates the need for a stabilising roll controller by introducing rollover prevention as a constraint on the control allocation problem. The major advantage of this approach is the control authority margin that remains with a high-level controller even during interventions for rollover prevention. In this work, the high-level control is assigned to a yaw stabilising controller. It could be replaced by any other controller. The constraint for rollover prevention could be replaced by or extended to different control objectives. This work uses differential braking for actuation. The use of additional or different actuators is possible. The developed control algorithm is computationally efficient and suitable for low-cost automotive electronic control units. The predictive design of the rollover prevention constraint does not require any sensor equipment in addition to the yaw controller. The method is validated using an industrial multi-body vehicle simulation environment.

Methanol and isoprene emissions from the fast growing tropical pioneer species Vismia guianensis (Aubl.) Pers. (Hypericaceae) in the central Amazon forest

DOE PAGES

Jardine, Kolby J.; Jardine, Angela B.; Souza, Vinicius F.; ...

2016-05-26

Isoprene (Is) emissions by plants represent a loss of carbon and energy resources leading to the initial hypothesis that fast growing pioneer species in secondary tropical forests allocate carbon primarily to growth at the expense of isoprenoid defenses. In this study, we quantified leaf isoprene and methanol emissions from the abundant pantropical pioneer tree species Vismia guianensis and ambient isoprene concentrations above a diverse secondary forest in the central Amazon. As photosynthetically active radiation (PAR) was varied (0 to 3000 µmol m -2 s -1) under standard leaf temperature (30 °C), isoprene emissions from V. guianensis increased without saturation upmore » to 80 nmol m -2 s -1. A nonlinear increase in isoprene emissions with respect to net photosynthesis (Pn) resulted in the fraction of Pn dedicated to isoprene emissions increasing with light intensity (up to 2 % of Pn). Emission responses to temperature under standard light conditions (PAR of 1000 µmol m -2 s -1) resulted in the classic uncoupling of isoprene emissions ( T opt, iso > 40 °C) from net photosynthesis ( T opt, Pn = 30.0–32.5 °C) with up to 7 % of Pn emitted as isoprene at 40 °C. Under standard environmental conditions of PAR and leaf temperature, young V. guianensis leaves showed high methanol emissions, low Pn, and low isoprene emissions. In contrast, mature leaves showed high Pn, high isoprene emissions, and low methanol emissions, highlighting the differential control of leaf phenology over methanol and isoprene emissions. High daytime ambient isoprene concentrations (11 ppbv) were observed above a secondary Amazon rainforest, suggesting that isoprene emissions are common among neotropical pioneer species. The results are not consistent with the initial hypothesis and support a functional role of methanol during leaf expansion and the establishment of photosynthetic machinery and a protective role of isoprene for photosynthesis during high temperature extremes regularly experienced in secondary rainforest ecosystems.« less

Methanol and isoprene emissions from the fast growing tropical pioneer species Vismia guianensis (Aubl.) Pers. (Hypericaceae) in the central Amazon forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jardine, Kolby J.; Jardine, Angela B.; Souza, Vinicius F.

Isoprene (Is) emissions by plants represent a loss of carbon and energy resources leading to the initial hypothesis that fast growing pioneer species in secondary tropical forests allocate carbon primarily to growth at the expense of isoprenoid defenses. In this study, we quantified leaf isoprene and methanol emissions from the abundant pantropical pioneer tree species Vismia guianensis and ambient isoprene concentrations above a diverse secondary forest in the central Amazon. As photosynthetically active radiation (PAR) was varied (0 to 3000 µmol m -2 s -1) under standard leaf temperature (30 °C), isoprene emissions from V. guianensis increased without saturation upmore » to 80 nmol m -2 s -1. A nonlinear increase in isoprene emissions with respect to net photosynthesis (Pn) resulted in the fraction of Pn dedicated to isoprene emissions increasing with light intensity (up to 2 % of Pn). Emission responses to temperature under standard light conditions (PAR of 1000 µmol m -2 s -1) resulted in the classic uncoupling of isoprene emissions ( T opt, iso > 40 °C) from net photosynthesis ( T opt, Pn = 30.0–32.5 °C) with up to 7 % of Pn emitted as isoprene at 40 °C. Under standard environmental conditions of PAR and leaf temperature, young V. guianensis leaves showed high methanol emissions, low Pn, and low isoprene emissions. In contrast, mature leaves showed high Pn, high isoprene emissions, and low methanol emissions, highlighting the differential control of leaf phenology over methanol and isoprene emissions. High daytime ambient isoprene concentrations (11 ppbv) were observed above a secondary Amazon rainforest, suggesting that isoprene emissions are common among neotropical pioneer species. The results are not consistent with the initial hypothesis and support a functional role of methanol during leaf expansion and the establishment of photosynthetic machinery and a protective role of isoprene for photosynthesis during high temperature extremes regularly experienced in secondary rainforest ecosystems.« less

Compensating differentials, labor market segmentation, and wage inequality.

PubMed

Daw, Jonathan; Hardie, Jessica Halliday

2012-09-01

Two literatures on work and the labor market draw attention to the importance of non-pecuniary job amenities. Social psychological perspectives on work suggest that workers have preferences for a range of job amenities (e.g. Halaby, 2003). The compensating differentials hypothesis predicts that workers navigate tradeoffs among different job amenities such that wage inequality overstates inequality in utility (Smith, 1979). This paper joins these perspectives by constructing a new measure of labor market success that evaluates the degree to which workers' job amenity preferences and outcomes match. This measure of subjective success is used to predict workers' job satisfaction and to test the hypothesis that some degree of labor force inequality in wages is due to preference-based tradeoffs among all job amenities. Findings demonstrate that the new measure predicts workers' job satisfaction and provides evidence for the presence of compensating differentials in the primary and intermediate, but not secondary, labor markets. Copyright © 2012 Elsevier Inc. All rights reserved.

Knowledge Base Refinement as Improving an Incorrect and Incomplete Domain Theory

DTIC Science & Technology

1990-04-01

Ginsberg et al., 1985), and RL (Fu and Buchanan, 1985), which perform empirical induction over a library of test cases. This chapter describes a new...state knowledge. Examples of high-level goals are: to test a hypothesis, to differentiate between several plausible hypotheses, to ask a clarifying...one tuple when we Group Hypotheses Test Hypothesis Applyrule Findout Strategy Metarule Strategy Metarule Strategy Metarule Strategy Metarule goal(group

Testing the Münch hypothesis of long distance phloem transport in plants.

PubMed

Knoblauch, Michael; Knoblauch, Jan; Mullendore, Daniel L; Savage, Jessica A; Babst, Benjamin A; Beecher, Sierra D; Dodgen, Adam C; Jensen, Kaare H; Holbrook, N Michele

2016-06-02

Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for the Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues.

Neural bases of selective attention in action video game players.

PubMed

Bavelier, D; Achtman, R L; Mani, M; Föcker, J

2012-05-15

Over the past few years, the very act of playing action video games has been shown to enhance several different aspects of visual selective attention, yet little is known about the neural mechanisms that mediate such attentional benefits. A review of the aspects of attention enhanced in action game players suggests there are changes in the mechanisms that control attention allocation and its efficiency (Hubert-Wallander, Green, & Bavelier, 2010). The present study used brain imaging to test this hypothesis by comparing attentional network recruitment and distractor processing in action gamers versus non-gamers as attentional demands increased. Moving distractors were found to elicit lesser activation of the visual motion-sensitive area (MT/MST) in gamers as compared to non-gamers, suggestive of a better early filtering of irrelevant information in gamers. As expected, a fronto-parietal network of areas showed greater recruitment as attentional demands increased in non-gamers. In contrast, gamers barely engaged this network as attentional demands increased. This reduced activity in the fronto-parietal network that is hypothesized to control the flexible allocation of top-down attention is compatible with the proposal that action game players may allocate attentional resources more automatically, possibly allowing more efficient early filtering of irrelevant information. Copyright © 2011 Elsevier Ltd. All rights reserved.

Expression of multiple sexual signals by fathers and sons in the East-Mediterranean barn swallow: are advertising strategies heritable?

PubMed

Vortman, Yoni; Safran, Rebecca J; Reiner Brodetzki, Tali; Dor, Roi; Lotem, Arnon

2015-01-01

The level of expression of sexually selected traits is generally determined by genes, environment and their interaction. In species that use multiple sexual signals which may be costly to produce, investing in the expression of one sexual signal may limit the expression of the other, favoring the evolution of a strategy for resource allocation among signals. As a result, even when the expression of sexual signals is condition dependent, the relative level of expression of each signal may be heritable. We tested this hypothesis in the East-Mediterranean barn swallow (Hirundo rustica transitiva), in which males have been shown to express two uncorrelated sexual signals: red-brown ventral coloration, and long tail streamers. We show that variation in both signals may partially be explained by age, as well as by paternal origin (genetic father-son regressions), but that the strongest similarity between fathers and sons is the relative allocation towards one trait or the other (relative expression index), rather than the expression of the traits themselves. These results suggest that the expression of one signal is not independent of the other, and that genetic strategies for resource allocation among sexual signals may be selected for during the evolution of multiple sexual signals.

Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage

PubMed Central

Ames, Bruce N.

2006-01-01

Inadequate dietary intakes of vitamins and minerals are widespread, most likely due to excessive consumption of energy-rich, micronutrient-poor, refined food. Inadequate intakes may result in chronic metabolic disruption, including mitochondrial decay. Deficiencies in many micronutrients cause DNA damage, such as chromosome breaks, in cultured human cells or in vivo. Some of these deficiencies also cause mitochondrial decay with oxidant leakage and cellular aging and are associated with late onset diseases such as cancer. I propose DNA damage and late onset disease are consequences of a triage allocation response to micronutrient scarcity. Episodic shortages of micronutrients were common during evolution. Natural selection favors short-term survival at the expense of long-term health. I hypothesize that short-term survival was achieved by allocating scarce micronutrients by triage, in part through an adjustment of the binding affinity of proteins for required micronutrients. If this hypothesis is correct, micronutrient deficiencies that trigger the triage response would accelerate cancer, aging, and neural decay but would leave critical metabolic functions, such as ATP production, intact. Evidence that micronutrient malnutrition increases late onset diseases, such as cancer, is discussed. A multivitamin-mineral supplement is one low-cost way to ensure intake of the Recommended Dietary Allowance of micronutrients throughout life. PMID:17101959

Expression of Multiple Sexual Signals by Fathers and Sons in the East-Mediterranean Barn Swallow: Are Advertising Strategies Heritable?

PubMed Central

Vortman, Yoni; Safran, Rebecca J.; Reiner Brodetzki, Tali; Dor, Roi; Lotem, Arnon

2015-01-01

The level of expression of sexually selected traits is generally determined by genes, environment and their interaction. In species that use multiple sexual signals which may be costly to produce, investing in the expression of one sexual signal may limit the expression of the other, favoring the evolution of a strategy for resource allocation among signals. As a result, even when the expression of sexual signals is condition dependent, the relative level of expression of each signal may be heritable. We tested this hypothesis in the East-Mediterranean barn swallow (Hirundo rustica transitiva), in which males have been shown to express two uncorrelated sexual signals: red-brown ventral coloration, and long tail streamers. We show that variation in both signals may partially be explained by age, as well as by paternal origin (genetic father-son regressions), but that the strongest similarity between fathers and sons is the relative allocation towards one trait or the other (relative expression index), rather than the expression of the traits themselves. These results suggest that the expression of one signal is not independent of the other, and that genetic strategies for resource allocation among sexual signals may be selected for during the evolution of multiple sexual signals. PMID:25679206

Allometric biomass partitioning under nitrogen enrichment: Evidence from manipulative experiments around the world.

PubMed

Peng, Yunfeng; Yang, Yuanhe

2016-06-28

Allometric and optimal hypotheses have been widely used to explain biomass partitioning in response to resource changes for individual plants; however, little evidence has been reported from measurements at the community level across a broad geographic scale. This study assessed the nitrogen (N) effect on community-level root to shoot (R/S) ratios and biomass partitioning functions by synthesizing global manipulative experiments. Results showed that, in aggregate, N addition decreased the R/S ratios in various biomes. However, the scaling slopes of the allometric equations were not significantly altered by the N enrichment, possibly indicating that N-induced reduction of the R/S ratio is a consequence of allometric allocation as a function of increasing plant size rather than an optimal partitioning model. To further illustrate this point, we developed power function models to explore the relationships between aboveground and belowground biomass for various biomes; then, we generated the predicted root biomass from the observed shoot biomass and predicted R/S ratios. The comparison of predicted and observed N-induced changes of the R/S ratio revealed no significant differences between each other, supporting the allometric allocation hypothesis. These results suggest that allometry, rather than optimal allocation, explains the N-induced reduction in the R/S ratio across global biomes.

Allocation of limited reserves to a clutch: A model explaining the lack of a relationship between clutch size and egg size

USGS Publications Warehouse

Flint, Paul L.; Grand, James B.; Sedinger, James S.

1996-01-01

Lack (1967, 1968) proposed that clutch size in waterfowl is limited by the nutrients available to females when producing eggs. He suggested that if nutrients available for clutch formation are limited, then species producing small eggs would, on average, lay more eggs than species with large eggs. Rohwer (1988) argues that this model should also apply within species. Thus, the nutrition-limitation hypothesis predicts a tradeoff among females between clutch size and egg size (Rohwer 1988). Field studies of single species consistently have failed to detect a negative relationship between clutch size and egg size (Rohwer 1988, Lessells et al. 1992, Rohwer and Eisenhauer 1989, Flint and Sedinger 1992, Flint and Grand 1996). The absence of such a relationship within species has been regarded as evidence against the hypothesis that nutrient availability limits clutch size (Rohwer 1988, 1991, 1992; Rohwer and Eisenhauer 1989).

A 3D Cellular Automaton for Cell Differentiation in a Solid Tumor with Plasticity

NASA Astrophysics Data System (ADS)

Margarit, David H.; Romanelli, Lilia; Fendrik, Alejandro J.

A model with spherical symmetry is proposed. We analyze the appropriate parameters of cell differentiation for different kinds of cells (Cancer Stem Cells (CSC) and Differentiated Cells (DC)). The plasticity (capacity to return from a DC to its previous state of CSC) is taken into account. Following this hypothesis, the dissemination of CSCs to another organ is analyzed. The location of the cells in the tumor and the plasticity range for possible metastasis is discussed.

CELLULAR DIFFERENTIATION AND THE AGING PROCESS IN CARTILAGINOUS TISSUES

PubMed Central

Shulman, Herbert J.; Meyer, Karl

1968-01-01

Primary cell cultures of differentiated chondrocytes were shown to produce chondroitin-4-sulfate as the predominant mucopolysaccharide, with suggestive evidence for the synthesis of keratan sulfate and possibly chondroitin-6-sulfate. Chicken embryonic cartilage was shown to be composed mainly of chondroitin-4-sulfate, with a small amount of chondroitin-6-sulfate, but essentially no keratan sulfate. These findings were compared to the data of others, and a hypothesis explaining the aging process in cartilage in terms of cellular differentiation was presented. PMID:5688079

Funding Diversity: Performance-Based Funding Regimes as Drivers of Differentiation in Higher Education Systems

ERIC Educational Resources Information Center

Sorlin, Sverker

2007-01-01

In most countries higher education institutions used to receive large portions of their funding by direct state allocation. For the past couple of decades this trust-based funding regime has been replaced by performance-based regimes. The article rests on the empirical observation that new funding regimes are increasingly becoming a policy…

Pass Rates in Primary School Leaving Examination in Tanzania: Implication for Efficient Allocation of Resources

ERIC Educational Resources Information Center

Kassile, Telemu

2014-01-01

This paper examines regional differentials in pass rates in Primary School Leaving Examination (PSLE) in Mainland Tanzania. In particular, the paper investigates the effects of pupil-teacher ratio (PTR), pupil-latrine ratio (PLR), pupil-classroom ratio (PCR), availability of electricity in schools, and secondary school and above education of women…

Gender Differences in the Maintenance of Response to Cognitive Behavior Therapy for Posttraumatic Stress Disorder

ERIC Educational Resources Information Center

Felmingham, Kim L.; Bryant, Richard A.

2012-01-01

Objective: To examine potential differential responses in men and women to cognitive behavior therapy for posttraumatic stress disorder (PTSD). Method: Fifty-two men and 56 women diagnosed with PTSD participated in randomized controlled trials of cognitive behavior therapy for PTSD. Participants were randomly allocated to either (a) exposure-only…

Evaluating the Impact and Determinants of Student Team Performance: Using LMS and CATME Data

ERIC Educational Resources Information Center

Braender, Lynn M.; Naples, Michele I.

2013-01-01

Practitioners find it difficult to allocate grades to individual students based on their contributions to the team project. They often use classroom observation of teamwork and student peer evaluations to differentiate an individual's grade from the group's grade, which can be subjective and imprecise. We used objective data from student activity…

An Empirical Investigation of Occupational Choice and Human Capital Accumulation at Mid-Life

ERIC Educational Resources Information Center

Xue, Yu

2010-01-01

Individual variation in labor supply can arise from more than just a choice among discrete occupation groups, especially given the joint process of wage determination and time allocation. Other factors can include differential preferences for earnings, the time length of work and other related occupational attributes. Using data from the Wisconsin…

Early differentiation of the Moon: Experimental and modeling studies

NASA Technical Reports Server (NTRS)

Longhi, J.

1986-01-01

Major accomplishments include the mapping out of liquidus boundaries of lunar and meteoritic basalts at low pressure; the refinement of computer models that simulate low pressure fractional crystallization; the development of a computer model to calculate high pressure partial melting of the lunar and Martian interiors; and the proposal of a hypothesis of early lunar differentiation based upon terrestrial analogs.

Multilevel Mediation: Cumulative Contextual Risk, Maternal Differential Treatment, and Children's Behavior within Families

ERIC Educational Resources Information Center

Meunier, Jean Christophe; Boyle, Michael; O'Connor, Thomas G.; Jenkins, Jennifer M.

2013-01-01

This study tests the hypothesis that links between contextual risk and children's outcomes are partially explained by differential parenting. Using multi-informant measurement and including up to four children per family (M[subscript age] = 3.51, SD = 2.38) in a sample of 397 families, indirect effects (through maternal differential…

Genomic regions with a history of divergent selection affect fitness of hybrids between two butterfly species.

PubMed

Gompert, Zachariah; Lucas, Lauren K; Nice, Chris C; Fordyce, James A; Forister, Matthew L; Buerkle, C Alex

2012-07-01

Speciation is the process by which reproductively isolated lineages arise, and is one of the fundamental means by which the diversity of life increases. Whereas numerous studies have documented an association between ecological divergence and reproductive isolation, relatively little is known about the role of natural selection in genome divergence during the process of speciation. Here, we use genome-wide DNA sequences and Bayesian models to test the hypothesis that loci under divergent selection between two butterfly species (Lycaeides idas and L. melissa) also affect fitness in an admixed population. Locus-specific measures of genetic differentiation between L. idas and L. melissa and genomic introgression in hybrids varied across the genome. The most differentiated genetic regions were characterized by elevated L. idas ancestry in the admixed population, which occurs in L. idas-like habitat, consistent with the hypothesis that local adaptation contributes to speciation. Moreover, locus-specific measures of genetic differentiation (a metric of divergent selection) were positively associated with extreme genomic introgression (a metric of hybrid fitness). Interestingly, concordance of differentiation and introgression was only partial. We discuss multiple, complementary explanations for this partial concordance. © 2012 The Author(s).

Ambiguity produces attention shifts in category learning

PubMed Central

Orgaz, Cristina; Luque, David; Nelson, James Byron

2016-01-01

It has been suggested that people and nonhuman animals protect their knowledge from interference by shifting attention toward the context when presented with information that contradicts their previous beliefs. Despite that suggestion, no studies have directly measured changes in attention while participants are exposed to an interference treatment. In the present experiments, we adapted a dot-probe task to track participants’ attention to cues and contexts while they were completing a simple category learning task. The results support the hypothesis that interference produces a change in the allocation of attention to cues and contexts. PMID:26980780

Optimal allocation in annual plants and its implications for drought response

NASA Astrophysics Data System (ADS)

Caldararu, Silvia; Smith, Matthew; Purves, Drew

2015-04-01

The concept of plant optimality refers to the plastic behaviour of plants that results in lifetime and offspring fitness. Optimality concepts have been used in vegetation models for a variety of processes, including stomatal conductance, leaf phenology and biomass allocation. Including optimality in vegetation models has the advantages of creating process based models with a relatively low complexity in terms of parameter numbers but which are capable of reproducing complex plant behaviour. We present a general model of plant growth for annual plants based on the hypothesis that plants allocate biomass to aboveground and belowground vegetative organs in order to maintain an optimal C:N ratio. The model also represents reproductive growth through a second optimality criteria, which states that plants flower when they reach peak nitrogen uptake. We apply this model to wheat and maize crops at 15 locations corresponding to FLUXNET cropland sites. The model parameters are data constrained using a Bayesian fitting algorithm to eddy covariance data, satellite derived vegetation indices, specifically the MODIS fAPAR product and field level crop yield data. We use the model to simulate the plant drought response under the assumption of plant optimality and show that the plants maintain unstressed total biomass levels under drought for a reduction in precipitation of up to 40%. Beyond that level plant response stops being plastic and growth decreases sharply. This behaviour results simply from the optimal allocation criteria as the model includes no explicit drought sensitivity component. Models that use plant optimality concepts are a useful tool for simulation plant response to stress without the addition of artificial thresholds and parameters.

The Kidney Donor Profile Index (KDPI) of marginal donors allocated by standardized pretransplant donor biopsy assessment: distribution and association with graft outcomes.

PubMed

Gandolfini, I; Buzio, C; Zanelli, P; Palmisano, A; Cremaschi, E; Vaglio, A; Piotti, G; Melfa, L; La Manna, G; Feliciangeli, G; Cappuccilli, M; Scolari, M P; Capelli, I; Panicali, L; Baraldi, O; Stefoni, S; Buscaroli, A; Ridolfi, L; D'Errico, A; Cappelli, G; Bonucchi, D; Rubbiani, E; Albertazzi, A; Mehrotra, A; Cravedi, P; Maggiore, U

2014-11-01

Pretransplant donor biopsy (PTDB)-based marginal donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the United States. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score<4 [median KDPI: 87; interquartile range (IQR): 78-94] and 62 with a score=4 [median KDPI: 87; IQR: 76-93]; 102 dual transplants [median KDPI: 93; IQR: 86-96]) and 248 single standard transplant controls (median KDPI: 36; IQR: 18-51). PTDB-based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80-90 and of 37% for kidneys with a KDPI of 91-100. Although 1-year estimated GFRs were significantly lower in recipients of marginal kidneys (-9.3, -17.9 and -18.8 mL/min, for dual transplants, single kidneys with PTDB score<4 and =4, respectively; p<0.001), graft survival (median follow-up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80-1.79; p=0.38]). In conclusion, PTDB-based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

Defective Number Sense or Impaired Access? Differential Impairments in Different Subgroups of Children With Mathematics Difficulties.

PubMed

Wong, Terry T-Y; Ho, Connie S-H; Tang, Joey

2017-01-01

Developmental dyscalculia (DD) is a specific learning disability in mathematics that affects around 6% of the population. Currently, the core deficit of DD remains unknown. While the number sense deficit hypothesis suggests that the core deficit of DD lies in the inability to represent nonsymbolic numerosity, the access deficit hypothesis suggests that the origin of this disability lies in the inability to associate numbers with the underlying magnitude representation. The present study compared the performance of DDs with their low-achieving (LA) and normally achieving peers in nonsymbolic numerosity processing and number-magnitude mapping over 1 year (from kindergarten to 1st grade). The results demonstrated differential impairments in different subgroups of children with mathematics difficulties. While DDs showed deficits in both nonsymbolic numerosity processing and number-magnitude mapping, LAs showed deficit only in the number-magnitude mapping. Furthermore, the deficit in number-magnitude mapping among the DD group was partially explained by their number sense deficit. The number sense deficit hypothesis is supported. Theoretical and practical implications are discussed. © Hammill Institute on Disabilities 2015.

Asynchronous hatching and food limitation: A test of Lack's hypothesis

USGS Publications Warehouse

Skagen, Susan Knight

1988-01-01

Lack's (1954, 1968) hypothesis that asynchronous hatching of altricial birds is an adaptive response to unpredictable food shortages during the breeding season was examined in the highly granivorous Zebra Finch (Poephila guttata). I compared growth and survival of nestlings in asynchronous and artificially created synchronous broods reared under food-limited and food-abundant conditions in an aviary. I also examined the role of parental experience on survival and growth of nestlings.There was no differential mortality of Zebra Finch nestlings due to either asynchrony or food abundance. Young in abundant food treatments grew more rapidly, however, than those in food-restricted treatments. Heaviest Zebra Finch nestlings in a brood grew more quickly than their lightest siblings when food was limited, supporting Lack's hypothesis. Further, differential survival of light and heavy siblings occurred when food was abundant, suggesting that asynchronous hatching can be maladaptive under some ecological conditions. Nestlings reared by inexperienced parents suffered greater mortality and slower growth when food was abundant than nestlings raised by experienced parents. Prefledging mass was correlated with size at adulthood

How temperament and personality contribute to the maladjustment of children with autism.

PubMed

De Pauw, Sarah S W; Mervielde, Ivan; Van Leeuwen, Karla G; De Clercq, Barbara J

2011-02-01

To test the spectrum hypothesis--postulating that clinical and non-clinical samples are primarily differentiated by mean-level differences--, this study evaluates differences in parent-rated temperament, personality and maladjustment among a low-symptom (N = 81), a high-symptom (N = 94) ASD-group, and a comparison group (N = 500). These classic spectrum hypothesis tests are extended by adding tests for similarity in variances, reliabilities and patterns of covariation between relevant variables. Children with ASD exhibit more extreme means, except for dominance. The low- and high-symptom ASD-groups are primarily differentiated by mean sociability and internal distress. Striking similarities in reliability and pattern of covariation of variables suggest that comparable processes link traits to maladaptation in low- and high-symptom children with ASD and in children with and without autism.

GENOME-ENABLED DISCOVERY OF CARBON SEQUESTRATION GENES IN POPLAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

DAVIS J M

2007-10-11

Plants utilize carbon by partitioning the reduced carbon obtained through photosynthesis into different compartments and into different chemistries within a cell and subsequently allocating such carbon to sink tissues throughout the plant. Since the phytohormones auxin and cytokinin are known to influence sink strength in tissues such as roots (Skoog & Miller 1957, Nordstrom et al. 2004), we hypothesized that altering the expression of genes that regulate auxin-mediated (e.g., AUX/IAA or ARF transcription factors) or cytokinin-mediated (e.g., RR transcription factors) control of root growth and development would impact carbon allocation and partitioning belowground (Fig. 1 - Renewal Proposal). Specifically, themore » ARF, AUX/IAA and RR transcription factor gene families mediate the effects of the growth regulators auxin and cytokinin on cell expansion, cell division and differentiation into root primordia. Invertases (IVR), whose transcript abundance is enhanced by both auxin and cytokinin, are critical components of carbon movement and therefore of carbon allocation. Thus, we initiated comparative genomic studies to identify the AUX/IAA, ARF, RR and IVR gene families in the Populus genome that could impact carbon allocation and partitioning. Bioinformatics searches using Arabidopsis gene sequences as queries identified regions with high degrees of sequence similarities in the Populus genome. These Populus sequences formed the basis of our transgenic experiments. Transgenic modification of gene expression involving members of these gene families was hypothesized to have profound effects on carbon allocation and partitioning.« less

Induction of Metamorphosis Causes Differences in Sex-Specific Allocation Patterns in Axolotls (Ambystoma mexicanum) that Have Different Growth Histories.

PubMed

Clarkson, Pamela M; Beachy, Christopher K

2015-12-01

We tested the hypothesis that salamanders growing at different rates would have allocation patterns that differ among male and female metamorphic and larval salamanders. We raised individual axolotls, Ambystoma mexicanum , on four food regimes: constant high growth (throughout the experiment), constant low growth (restricted throughout the experiment), high growth switched to low growth (ad libitum switched after 140 d to restricted), and low growth switched to high growth (restricted switched after 140 d to ad libitum). Because axolotls are obligate paedomorphs, we exposed half of the salamanders to thyroid hormone to induce metamorphosis. We assayed growth and dissected and weighed gonads and fat bodies. Salamanders that were switched from restricted to ad libitum food regime delayed metamorphosis. In all treatment groups, females had larger gonads than males and males had larger fat bodies than females. The association between storage and reproduction differed between larvae and metamorphs and depended on sex.

Task set induces dynamic reallocation of resources in visual short-term memory.

PubMed

Sheremata, Summer L; Shomstein, Sarah

2017-08-01

Successful interaction with the environment requires the ability to flexibly allocate resources to different locations in the visual field. Recent evidence suggests that visual short-term memory (VSTM) resources are distributed asymmetrically across the visual field based upon task demands. Here, we propose that context, rather than the stimulus itself, determines asymmetrical distribution of VSTM resources. To test whether context modulates the reallocation of resources to the right visual field, task set, defined by memory-load, was manipulated to influence visual short-term memory performance. Performance was measured for single-feature objects embedded within predominantly single- or two-feature memory blocks. Therefore, context was varied to determine whether task set directly predicts changes in visual field biases. In accord with the dynamic reallocation of resources hypothesis, task set, rather than aspects of the physical stimulus, drove improvements in performance in the right- visual field. Our results show, for the first time, that preparation for upcoming memory demands directly determines how resources are allocated across the visual field.

Economic scarcity alters the perception of race

PubMed Central

Krosch, Amy R.; Amodio, David M.

2014-01-01

When the economy declines, racial minorities are hit the hardest. Although existing explanations for this effect focus on institutional causes, recent psychological findings suggest that scarcity may also alter perceptions of race in ways that exacerbate discrimination. We tested the hypothesis that economic resource scarcity causes decision makers to perceive African Americans as “Blacker” and that this visual distortion elicits disparities in the allocation of resources. Studies 1 and 2 demonstrated that scarcity altered perceptions of race, lowering subjects’ psychophysical threshold for seeing a mixed-race face as “Black” as opposed to “White.” In studies 3 and 4, scarcity led subjects to visualize African American faces as darker and more “stereotypically Black,” compared with a control condition. When presented to naïve subjects, face representations produced under scarcity elicited smaller allocations than control-condition representations. Together, these findings introduce a novel perceptual account for the proliferation of racial disparities under economic scarcity. PMID:24927595

Neuroscientific evidence for defensive avoidance of fear appeals

PubMed Central

Kessels, Loes T E; Ruiter, Robert A C; Wouters, Liesbeth; Jansma, Bernadette M

2014-01-01

Previous studies indicate that people respond defensively to threatening health information, especially when the information challenges self-relevant goals. The authors investigated whether reduced acceptance of self-relevant health risk information is already visible in early attention allocation processes. In two experimental studies, participants were watching high- and low-threat health commercials, and at the same time had to pay attention to specific odd auditory stimuli in a sequence of frequent auditory stimuli (odd ball paradigm). The amount of attention allocation was measured by recording event-related brain potentials (i.e., P300 ERPs) and reaction times. Smokers showed larger P300 amplitudes in response to the auditory targets while watching high-threat instead of low-threat anti-smoking commercials. In contrast, non-smokers showed smaller P300 amplitudes during watching high as opposed to low threat anti-smoking commercials. In conclusion, the findings provide further neuroscientific support for the hypothesis that threatening health information causes more avoidance responses among those for whom the health threat is self-relevant. PMID:24811878

Search for a Differentiated Asteroid Family

NASA Astrophysics Data System (ADS)

Thomas, Cristina A.; Lim, Lucy F.; Trilling, David E.; Moskovitz, Nicholas

2014-08-01

Dynamical asteroid families resulting from catastrophic disruptions represent the interiors of their former parent bodies. Differentiation of a large initially chondritic parent body is expected to produce an ``onion shell" object with a metal core, a thick olivine-rich mantle, and a thin basaltic crust. However, instead of the mineralogical diversity expected from the disruption of a differentiated parent body, most asteroid families tend to show similar spectra among the members. Moreover, spectra of metal-like materials and olivine-dominated assemblages have not been detected in asteroid families in the Main Belt and the expected mantle material is missing from the meteorite record. The deficit of olivine-rich mantle material in the meteorite record and in asteroid observations is known as the ``Missing Mantle" problem. For years the best explanation for the lack of mantle material has been the ``battered to bits" hypothesis that states that all differentiated parent bodies (aside from Vesta) were disrupted very early in the solar system and the resulting olivine-rich material was collisionally broken down until the object diameters fell below our observational limits. However, in a new, competing, hypothesis, Elkins-Tanton et al. (2013) has suggested that previous work has overestimated the amount of olivine produced by the differentiation of a chondritic parent body. We propose to obtain visible spectra of asteroids within the Massalia, Merxia, and Agnia S-type families to search for compositional variations that are indicators of differentiation and to quantitatively constrain the two competing ``Missing Mantle" hypotheses.

Offspring Size and Reproductive Allocation in Harvester Ants.

PubMed

Wiernasz, Diane C; Cole, Blaine J

2018-01-01

A fundamental decision that an organism must make is how to allocate resources to offspring, with respect to both size and number. The two major theoretical approaches to this problem, optimal offspring size and optimistic brood size models, make different predictions that may be reconciled by including how offspring fitness is related to size. We extended the reasoning of Trivers and Willard (1973) to derive a general model of how parents should allocate additional resources with respect to the number of males and females produced, and among individuals of each sex, based on the fitness payoffs of each. We then predicted how harvester ant colonies should invest additional resources and tested three hypotheses derived from our model, using data from 3 years of food supplementation bracketed by 6 years without food addition. All major results were predicted by our model: food supplementation increased the number of reproductives produced. Male, but not female, size increased with food addition; the greatest increases in male size occurred in colonies that made small females. We discuss how use of a fitness landscape improves quantitative predictions about allocation decisions. When parents can invest differentially in offspring of different types, the best strategy will depend on parental state as well as the effect of investment on offspring fitness.

A Genome-Wide Test of the Differential Susceptibility Hypothesis Reveals a Genetic Predictor of Differential Response to Psychological Treatments for Child Anxiety Disorders

PubMed Central

Keers, Robert; Coleman, Jonathan R.I.; Lester, Kathryn J.; Roberts, Susanna; Breen, Gerome; Thastum, Mikael; Bögels, Susan; Schneider, Silvia; Heiervang, Einar; Meiser-Stedman, Richard; Nauta, Maaike; Creswell, Cathy; Thirlwall, Kerstin; Rapee, Ronald M.; Hudson, Jennifer L.; Lewis, Cathryn; Plomin, Robert; Eley, Thalia C.

2016-01-01

Background The differential susceptibly hypothesis suggests that certain genetic variants moderate the effects of both negative and positive environments on mental health and may therefore be important predictors of response to psychological treatments. Nevertheless, the identification of such variants has so far been limited to preselected candidate genes. In this study we extended the differential susceptibility hypothesis from a candidate gene to a genome-wide approach to test whether a polygenic score of environmental sensitivity predicted response to cognitive behavioural therapy (CBT) in children with anxiety disorders. Methods We identified variants associated with environmental sensitivity using a novel method in which within-pair variability in emotional problems in 1,026 monozygotic twin pairs was examined as a function of the pairs' genotype. We created a polygenic score of environmental sensitivity based on the whole-genome findings and tested the score as a moderator of parenting on emotional problems in 1,406 children and response to individual, group and brief parent-led CBT in 973 children with anxiety disorders. Results The polygenic score significantly moderated the effects of parenting on emotional problems and the effects of treatment. Individuals with a high score responded significantly better to individual CBT than group CBT or brief parent-led CBT (remission rates: 70.9, 55.5 and 41.6%, respectively). Conclusions Pending successful replication, our results should be considered exploratory. Nevertheless, if replicated, they suggest that individuals with the greatest environmental sensitivity may be more likely to develop emotional problems in adverse environments but also benefit more from the most intensive types of treatment. PMID:27043157

Testing the Münch hypothesis of long distance phloem transport in plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knoblauch, Michael; Knoblauch, Jan; Mullendore, Daniel L.

Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for themore » Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues.« less

Testing the Münch hypothesis of long distance phloem transport in plants

DOE PAGES

Knoblauch, Michael; Knoblauch, Jan; Mullendore, Daniel L.; ...

2016-06-02

Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for themore » Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues.« less

The Interplay of Energy Balance and Daily Timing of Activity in a Subterranean Rodent: A Laboratory and Field Approach.

PubMed

Tachinardi, Patricia; Valentinuzzi, Verónica S; Oda, Gisele A; Buck, C Loren

The tuco-tuco (Ctenomys aff. knighti) is among the rodent species known to be nocturnal under standard laboratory conditions and diurnal under natural conditions. The circadian thermoenergetics (CTE) hypothesis postulates that switches in activity timing are a response to energetic challenges; daytime activity reduces thermoregulatory costs by consolidating activity to the warmest part of the day. Studying wild animals under both captive and natural conditions can increase understanding of how temporal activity patterns are shaped by the environment and could serve as a test of the CTE hypothesis. We estimated the effects of activity timing on energy expenditure for the tuco-tuco by combining laboratory measurements of metabolic rate with environmental temperature records in both winter and summer. We showed that, in winter, there would be considerable energy savings if activity is allocated at least partially during daylight, lending support to the CTE hypothesis. In summer, the impact of activity timing on energy expenditure is small, suggesting that during this season other factors, such as predation risk, water balance, and social interaction, may have more important roles than energetics in the determination of activity time.

Shading responses of carbon allocation dynamics in mountain grassland

NASA Astrophysics Data System (ADS)

Bahn, M.; Lattanzi, F. A.; Brueggemann, N.; Siegwolf, R. T.; Richter, A.

2012-12-01

Carbon (C) allocation strongly influences plant and soil processes. Global environmental changes can alter source - sink relations of plants with potential implications for C allocation. Short-term C allocation dynamics in ecosystems and their responses to environmental changes are still poorly understood. To analyze effects of assimilate supply (i.e. C source strength) on ecosystem C allocation dynamics and the role of non-structural carbohydrates, canopy sections of a mountain meadow were pulse labeled with 13CO2 and subsequently shaded for a week or left unshaded (control). Tracer dynamics in above- and belowground sucrose and starch pools were analysed and coupled using compartmental modelling. The hypothesis was tested that shading affects tracer dynamics in non-structural carbohydrates and diminishes the transfer of recently assimilated C to roots and their storage pools. In unshaded plots up to 40% of assimilated C was routed through short-term storage in shoot starch and sucrose to buffer day / night cycles in photosynthesis. Shoot- and root sucrose and shoot starch were kinetically closely related pools. The tracer dynamics of the modelled root sucrose pool corresponded well with those in soil CO2 efflux. Root starch played no role in buffering day / night cycles and likely acted as a seasonal store. Shading strongly reduced sucrose and starch concentrations in shoots but not roots and resulted in a massive reduction of leaf respiration, while root respiration was much less diminished. Shading affected tracer dynamics in sucrose and starch of shoots: shoot starch rapidly lost tracer, while sucrose transiently increased its tracer content. Surprisingly, shading did not alter the dynamics of root carbohydrates. Even under severe C limitation after one week of shading, tracer C continued to be incorporated in root starch. Also the amount of 13C incorporated in phospholipid fatty acids of soil microbial communities was not reduced by shading, though its residence time followed a changed pattern, suggesting an influence of C source strength on the utilization and turnover of recent plant-derived C. These findings will be discussed in the broader context of plant and ecosystem carbon allocation, with particular reference to the concepts of 'source versus sink strength' and 'passive versus active C storage'.

A two-step hierarchical hypothesis set testing framework, with applications to gene expression data on ordered categories

PubMed Central

2014-01-01

Background In complex large-scale experiments, in addition to simultaneously considering a large number of features, multiple hypotheses are often being tested for each feature. This leads to a problem of multi-dimensional multiple testing. For example, in gene expression studies over ordered categories (such as time-course or dose-response experiments), interest is often in testing differential expression across several categories for each gene. In this paper, we consider a framework for testing multiple sets of hypothesis, which can be applied to a wide range of problems. Results We adopt the concept of the overall false discovery rate (OFDR) for controlling false discoveries on the hypothesis set level. Based on an existing procedure for identifying differentially expressed gene sets, we discuss a general two-step hierarchical hypothesis set testing procedure, which controls the overall false discovery rate under independence across hypothesis sets. In addition, we discuss the concept of the mixed-directional false discovery rate (mdFDR), and extend the general procedure to enable directional decisions for two-sided alternatives. We applied the framework to the case of microarray time-course/dose-response experiments, and proposed three procedures for testing differential expression and making multiple directional decisions for each gene. Simulation studies confirm the control of the OFDR and mdFDR by the proposed procedures under independence and positive correlations across genes. Simulation results also show that two of our new procedures achieve higher power than previous methods. Finally, the proposed methodology is applied to a microarray dose-response study, to identify 17 β-estradiol sensitive genes in breast cancer cells that are induced at low concentrations. Conclusions The framework we discuss provides a platform for multiple testing procedures covering situations involving two (or potentially more) sources of multiplicity. The framework is easy to use and adaptable to various practical settings that frequently occur in large-scale experiments. Procedures generated from the framework are shown to maintain control of the OFDR and mdFDR, quantities that are especially relevant in the case of multiple hypothesis set testing. The procedures work well in both simulations and real datasets, and are shown to have better power than existing methods. PMID:24731138

Explorations of Psyche and Callisto Enabled by Ion Propulsion

NASA Technical Reports Server (NTRS)

Wenkert, Daniel D.; Landau, Damon F.; Bills, Bruce G.; Elkins-Tanton, Linda T.

2013-01-01

Recent developments in ion propulsion (specifically solar electric propulsion - SEP) have the potential for dramatically reducing the transportation cost of planetary missions. We examine two representative cases, where these new developments enable missions which, until recently, would have required resouces well beyond those allocated to the Discovery program. The two cases of interest address differentiation of asteroids and large icy satellites

Exploring the Politics of Differential Resource Allocation: Implications for Policy Design and Leadership Practice

ERIC Educational Resources Information Center

Halverson, Thomas J.; Plecki, Margaret L.

2015-01-01

This qualitative case study explores the political and leadership challenges imbedded within the implementation of a district-wide resource reallocation policy. Based on a two-year study of a medium-sized district's efforts to address changing demographics of families in the district and a widening achievement gap, we draw upon concepts from…

Random Forest Segregation of Drug Responses May Define Regions of Biological Significance.

PubMed

Bukhari, Qasim; Borsook, David; Rudin, Markus; Becerra, Lino

2016-01-01

The ability to assess brain responses in unsupervised manner based on fMRI measure has remained a challenge. Here we have applied the Random Forest (RF) method to detect differences in the pharmacological MRI (phMRI) response in rats to treatment with an analgesic drug (buprenorphine) as compared to control (saline). Three groups of animals were studied: two groups treated with different doses of the opioid buprenorphine, low (LD), and high dose (HD), and one receiving saline. PhMRI responses were evaluated in 45 brain regions and RF analysis was applied to allocate rats to the individual treatment groups. RF analysis was able to identify drug effects based on differential phMRI responses in the hippocampus, amygdala, nucleus accumbens, superior colliculus, and the lateral and posterior thalamus for drug vs. saline. These structures have high levels of mu opioid receptors. In addition these regions are involved in aversive signaling, which is inhibited by mu opioids. The results demonstrate that buprenorphine mediated phMRI responses comprise characteristic features that allow a supervised differentiation from placebo treated rats as well as the proper allocation to the respective drug dose group using the RF method, a method that has been successfully applied in clinical studies.

Effects of Grazing on Above- vs. Below-Ground Biomass Allocation of Alpine Grasslands on the Northern Tibetan Plateau

PubMed Central

Zeng, Chaoxu; Wu, Jianshuang; Zhang, Xianzhou

2015-01-01

Biomass allocation is an essential concept for understanding above- vs. below-ground functions and for predicting the dynamics of community structure and ecosystem service under ongoing climate change. There is rare available knowledge of grazing effects on biomass allocation in multiple zonal alpine grassland types along climatic gradients across the Northern Tibetan Plateau. We collected the peak above- and below-ground biomass (AGB and BGB) values at 106 pairs of well-matched grazed vs. fenced sites during summers of 2010–2013, of which 33 pairs were subject to meadow, 52 to steppe and 21 to desert-steppe. The aboveground net primary productivity (ANPP) was represented by the peak AGB while the belowground net primary productivity (BNPP) was estimated from ANPP, the ratio of living vs. dead BGB, and the root turnover rate. Two-ways analyses of variance (ANOVA) and paired samples comparisons with t-test were applied to examine the effects of pasture managements (PMS, i.e., grazed vs. fenced) and zonal grassland types on both ANPP and BNPP. Allometric and isometric allocation hypotheses were also tested between logarithmically transformed ANPP and BNPP using standardized major axis (SMA) analyses across grazed, fenced and overall sites. In our study, a high community-dependency was observed to support the allometric biomass allocation hypothesis, in association with decreased ANPP and a decreasing-to-increasing BNPP proportions with increasing aridity across the Northern Tibetan Plateau. Grazing vs. fencing seemed to have a trivial effect on ANPP compared to the overwhelming influence of different zonal grassland types. Vegetation links above- and below-ground ecological functions through integrated meta-population adaptive strategies to the increasing severity of habitat conditions. Therefore, more detailed studies on functional diversity are essentially to achieve conservation and sustainability goals under ongoing climatic warming and intensifying human influences. PMID:26284515

Nitrogen fertilization decouples roots and microbes: Reductions in belowground carbon allocation limit microbial activity

NASA Astrophysics Data System (ADS)

Carrara, J.; Walter, C. A.; Govindarajulu, R.; Hawkins, J.; Brzostek, E. R.

2017-12-01

Nitrogen (N) deposition has enhanced the ability of trees to capture atmospheric carbon (C). The effect of elevated N on belowground C cycling, however, is variable and response mechanisms are largely unknown. Recent research has highlighted distinct differences between ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) trees in the strength of root-microbial interactions. In particular, ECM trees send more C to rhizosphere microbes to stimulate enzyme activity and nutrient mobilization than AM trees, which primarily rely on saprotrophic microbes to mobilize N. As such, we hypothesized that N fertilization would weaken root-microbial interactions and soil decomposition in ECM stands more than in AM stands. To test this hypothesis, we measured root-microbial interactions in ECM and AM plots in two long-term N fertilization studies, the Fernow Experimental Forest, WV and Bear Brook Watershed, ME. We found that N fertilization led to declines in plant C allocation belowground to fine root biomass, branching, and root exudation in ECM stands to a greater extent than in AM stands. As ECM roots are tightly coupled to the soil microbiome through energy and nutrient exchange, reductions in belowground C allocation were mirrored by shifts in microbial community composition and reductions in fungal gene expression. These shifts were accompanied by larger reductions in fungal-derived lignolytic and hydrolytic enzyme activity in ECM stands than in AM stands. In contrast, as the AM soil microbiome is less reliant on trees for C and are more adapted to high inorganic nutrient environments, the soil metagenome and transcriptome were more resilient to decreases in belowground C allocation. Collectively, our results indicate the N fertilization decoupled root-microbial interactions by reducing belowground carbon allocation in ECM stands. Thus, N fertilization may reduce soil turnover and increase soil C storage to a greater extent in forests dominated by ECM than AM trees.

Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health.

PubMed

Said-Mohamed, Rihlat; Pettifor, John M; Norris, Shane A

2018-01-01

Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health. © 2017 Wiley Periodicals, Inc.

The lunar crust - A product of heterogeneous accretion or differentiation of a homogeneous moon

NASA Technical Reports Server (NTRS)

Brett, R.

1973-01-01

The outer portion of the moon (including the aluminum-rich crust and the source regions of mare basalts) was either accreted heterogeneously or was the product of widespread differentiation of an originally homogeneous source. Existing evidence for and against each of these two models is reviewed. It is concluded that the accretionary model presents more problems than it solves, and the model involving differentiation of an originally homogeneous moon is considered to be more plausible. A hypothesis for the formation of mare basalts is advanced.

Whole-plant allocation to storage and defense in juveniles of related evergreen and deciduous shrub species

PubMed Central

Wyka, T.P.; Karolewski, P.; Żytkowiak, R.; Chmielarz, P.; Oleksyn, J.

2016-01-01

In evergreen plants, old leaves may contribute photosynthate to initiation of shoot growth in the spring. They might also function as storage sites for carbohydrates and nitrogen (N). We hence hypothesized that whole-plant allocation of carbohydrates and N to storage in stems and roots may be lower in evergreen than in deciduous species. We selected three species pairs consisting of an evergreen and a related deciduous species: Mahonia aquifolium (Pursh) Nutt. and Berberis vulgaris L. (Berberidaceae), Prunus laurocerasus L. and Prunus serotina Ehrh. (Rosaceae), and Viburnum rhytidophyllum Hemsl. and Viburnum lantana L. (Adoxaceae). Seedlings were grown outdoors in pots and harvested on two dates during the growing season for the determination of biomass, carbohydrate and N allocation ratios. Plant size-adjusted pools of nonstructural carbohydrates in stems and roots were lower in the evergreen species of Berberidaceae and Adoxaceae, and the slope of the carbohydrate pool vs plant biomass relationship was lower in the evergreen species of Rosaceae compared with the respective deciduous species, consistent with the leading hypothesis. Pools of N in stems and roots, however, did not vary with leaf habit. In all species, foliage contained more than half of the plant’s nonstructural carbohydrate pool and, in late summer, also more than half of the plant’s N pool, suggesting that in juvenile individuals of evergreen species, leaves may be a major storage site. Additionally, we hypothesized that concentration of defensive phenolic compounds in leaves should be higher in evergreen than in deciduous species, because the lower carbohydrate pool in stems and roots of the former restricts their capacity for regrowth following herbivory and also because of the need to protect their longer-living foliage. Our results did not support this hypothesis, suggesting that evergreen plants may rely predominantly on structural defenses. In summary, our study indicates that leaf habit has consequences for storage economics at the whole-plant level, with evergreen shrub species storing less carbohydrates (but not N) per unit plant biomass than deciduous species. PMID:26507271

Whole-plant allocation to storage and defense in juveniles of related evergreen and deciduous shrub species.

PubMed

Wyka, T P; Karolewski, P; Żytkowiak, R; Chmielarz, P; Oleksyn, J

2016-05-01

In evergreen plants, old leaves may contribute photosynthate to initiation of shoot growth in the spring. They might also function as storage sites for carbohydrates and nitrogen (N). We hence hypothesized that whole-plant allocation of carbohydrates and N to storage in stems and roots may be lower in evergreen than in deciduous species. We selected three species pairs consisting of an evergreen and a related deciduous species: Mahonia aquifolium (Pursh) Nutt. and Berberis vulgaris L. (Berberidaceae), Prunus laurocerasus L. and Prunus serotina Ehrh. (Rosaceae), and Viburnum rhytidophyllum Hemsl. and Viburnum lantana L. (Adoxaceae). Seedlings were grown outdoors in pots and harvested on two dates during the growing season for the determination of biomass, carbohydrate and N allocation ratios. Plant size-adjusted pools of nonstructural carbohydrates in stems and roots were lower in the evergreen species of Berberidaceae and Adoxaceae, and the slope of the carbohydrate pool vs plant biomass relationship was lower in the evergreen species of Rosaceae compared with the respective deciduous species, consistent with the leading hypothesis. Pools of N in stems and roots, however, did not vary with leaf habit. In all species, foliage contained more than half of the plant's nonstructural carbohydrate pool and, in late summer, also more than half of the plant's N pool, suggesting that in juvenile individuals of evergreen species, leaves may be a major storage site. Additionally, we hypothesized that concentration of defensive phenolic compounds in leaves should be higher in evergreen than in deciduous species, because the lower carbohydrate pool in stems and roots of the former restricts their capacity for regrowth following herbivory and also because of the need to protect their longer-living foliage. Our results did not support this hypothesis, suggesting that evergreen plants may rely predominantly on structural defenses. In summary, our study indicates that leaf habit has consequences for storage economics at the whole-plant level, with evergreen shrub species storing less carbohydrates (but not N) per unit plant biomass than deciduous species. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Differential Effect of Correct Name Translation on Human and Automated Judgments of Translation Acceptability: A Pilot Study

DTIC Science & Technology

2008-09-01

in the Input Hypothesis (IH) of Krashen (1981) and the Expectancy Hypothesis (EH) of Oller and Richard-Amato (1983). Situations where readers attempt...hypothesizing what will come next can be conceptualized in terms of grammar-based expectancies ( Oller , 1983). New elements are interspersed with known...Testing. Applied Language Learning 1993, 4. Clifford, R.; Granoien, N.; Jones, D. A.; Shen, W.; Weinstein, C. J . The Effect of Text Difficulty on

What was your question again? Types of medical studies.

PubMed

Jupiter, Daniel C

2014-01-01

Medical literature comes in all shapes and sizes, from animal studies to prospective clinical trials to retrospective chart reviews. In all of these cases, it is worth asking: What are the intellectual goals of the study: description, hypothesis testing, or hypothesis generating? This differentiation can help shape our view of the success or failure of the scientific effort. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Social and economic ideologies differentially predict prejudice across the political spectrum, but social issues are most divisive.

PubMed

Crawford, Jarret T; Brandt, Mark J; Inbar, Yoel; Chambers, John R; Motyl, Matt

2017-03-01

Liberals and conservatives both express prejudice toward ideologically dissimilar others (Brandt et al., 2014). Previous work on ideological prejudice did not take advantage of evidence showing that ideology is multidimensional, with social and economic ideologies representing related but separable belief systems. In 5 studies (total N = 4912), we test 3 competing hypotheses of a multidimensional account of ideological prejudice. The dimension-specific symmetry hypothesis predicts that social and economic ideologies differentially predict prejudice against targets who are perceived to vary on the social and economic political dimensions, respectively. The social primacy hypothesis predicts that such ideological worldview conflict is experienced more strongly along the social than economic dimension. The social-specific asymmetry hypothesis predicts that social conservatives will be more prejudiced than social liberals, with no specific hypotheses for the economic dimension. Using multiple target groups, multiple prejudice measures (e.g., global evaluations, behavior), and multiple social and economic ideology measures (self-placement, issue positions), we found relatively consistent support for the dimension-specific symmetry and social primacy hypotheses, and no support for the social-specific asymmetry hypothesis. These results suggest that worldview conflict and negative intergroup attitudes and behaviors are dimension-specific, but that the social dimension appears to inspire more political conflict than the economic dimension. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Procedural justice, occupational identification, and organizational commitment.

DOT National Transportation Integrated Search

1992-06-01

Extending Tyler's (1989) group-value model, the present study tested the hypothesis that procedural justice may be of differential salience in the development of organizational commitment among individuals who identify primarily with their employing ...

A brain network instantiating approach and avoidance motivation.

PubMed

Spielberg, Jeffrey M; Miller, Gregory A; Warren, Stacie L; Engels, Anna S; Crocker, Laura D; Banich, Marie T; Sutton, Bradley P; Heller, Wendy

2012-09-01

Research indicates that dorsolateral prefrontal cortex (DLPFC) is important for pursuing goals, and areas of DLPFC are differentially involved in approach and avoidance motivation. Given the complexity of the processes involved in goal pursuit, DLPFC is likely part of a network that includes orbitofrontal cortex (OFC), cingulate, amygdala, and basal ganglia. This hypothesis was tested with regard to one component of goal pursuit, the maintenance of goals in the face of distraction. Examination of connectivity with motivation-related areas of DLPFC supported the network hypothesis. Differential patterns of connectivity suggest a distinct role for DLPFC areas, with one involved in selecting approach goals, one in selecting avoidance goals, and one in selecting goal pursuit strategies. Finally, differences in trait motivation moderated connectivity between DLPFC and OFC, suggesting that this connectivity is important for instantiating motivation. Copyright © 2012 Society for Psychophysiological Research.

A Brain Network Instantiating Approach and Avoidance Motivation

PubMed Central

Spielberg, Jeffrey M.; Miller, Gregory A.; Warren, Stacie L.; Engels, Anna S.; Crocker, Laura D.; Banich, Marie T.; Sutton, Bradley P.; Heller, Wendy

2015-01-01

Research indicates that dorsolateral prefrontal cortex (DLPFC) is important for pursuing goals, and areas of DLPFC are differentially involved in approach and avoidance motivation. Given the complexity of the processes involved in goal pursuit, DLPFC is likely part of a network that includes orbitofrontal cortex (OFC), cingulate, amygdala, and basal ganglia. This hypothesis was tested with regard to one component of goal pursuit, the maintenance of goals in the face of distraction. Examination of connectivity with motivation-related areas of DLPFC supported the network hypothesis. Differential patterns of connectivity suggest a distinct role for DLPFC areas, with one involved in selecting approach goals, one in selecting avoidance goals, and one in selecting goal pursuit strategies. Finally, differences in trait motivation moderated connectivity between DLPFC and OFC, suggesting that this connectivity is important for instantiating motivation. PMID:22845892

It's DE-licious: A Recipe for Differential Expression Analyses of RNA-seq Experiments Using Quasi-Likelihood Methods in edgeR.

PubMed

Lun, Aaron T L; Chen, Yunshun; Smyth, Gordon K

2016-01-01

RNA sequencing (RNA-seq) is widely used to profile transcriptional activity in biological systems. Here we present an analysis pipeline for differential expression analysis of RNA-seq experiments using the Rsubread and edgeR software packages. The basic pipeline includes read alignment and counting, filtering and normalization, modelling of biological variability and hypothesis testing. For hypothesis testing, we describe particularly the quasi-likelihood features of edgeR. Some more advanced downstream analysis steps are also covered, including complex comparisons, gene ontology enrichment analyses and gene set testing. The code required to run each step is described, along with an outline of the underlying theory. The chapter includes a case study in which the pipeline is used to study the expression profiles of mammary gland cells in virgin, pregnant and lactating mice.

Soldiers in a Stingless Bee.

PubMed

Hammel, Benedikt; Vollet-Neto, Ayrton; Menezes, Cristiano; Nascimento, Fabio S; Engels, Wolf; Grüter, Christoph

2016-01-01

The differentiation of workers into morphological subcastes (e.g., soldiers) represents an important evolutionary transition and is thought to improve division of labor in social insects. Soldiers occur in many ant and termite species, where they make up a small proportion of the workforce. A common assumption of worker caste evolution is that soldiers are behavioral specialists. Here, we report the first test of the "rare specialist" hypothesis in a eusocial bee. Colonies of the stingless bee Tetragonisca angustula are defended by a small group of morphologically differentiated soldiers. Contrary to the rare specialist hypothesis, we found that soldiers worked more (+34%-41%) and performed a greater variety of tasks (+23%-34%) than other workers, particularly early in life. Our results suggest a "rare elite" function of soldiers in T. angustula, that is, that they perform a disproportionately large amount of the work. Division of labor was based on a combination of temporal and physical castes, but soldiers transitioned faster from one task to the next. We discuss why the rare specialist assumption might not hold in species with a moderate degree of worker differentiation.

Temnothorax crasecundus sp. n. – a cryptic Eurocaucasian ant species (Hymenoptera, Formicidae) discovered by Nest Centroid Clustering

PubMed Central

Seifert, Bernhard; Csösz, Sandor

2015-01-01

Abstract The paper integrates two independent studies of numeric morphology-based alpha-taxonomy of the cryptic ant species Temnothorax crassispinus (Karavajev, 1926) and Temnothorax crasecundus sp. n. conducted by different investigators, using different equipment, considering different character combinations and evaluating different samples. Samples investigated included 603 individual workers from 203 nests – thereof 104 nest samples measured by Seifert and 99 by Csösz. The material originated from Europe, Asia Minor and Caucasia. There was a very strong interspecific overlap in any of the 29 shape characters recorded and subjective expert determination failed in many cases. Primary classification hypotheses were formed by the exploratory data analysis Nest Centroid (NC) clustering and corrected to final species hypotheses by an iterative linear discriminant analysis algorithm. The evaluation of Seifert’s and Csösz’s data sets arrived at fully congruent conclusions. NC-Ward and NC-K-means clustering disagreed from the final species hypothesis in only 1.9 and 1.9% of the samples in Seifert’s data set and by 1.1 and 2.1% in Csösz’s data set which is a strong argument for heterospecificity. The type series of Temnothorax crassispinus and Temnothorax crasecundus sp. n. were allocated to different clusters with p = 0.9851 and p = 0.9912 respectively. The type series of the junior synonym Temnothorax slavonicus (Seifert, 1995) was allocated to the Temnothorax crassispinus cluster with p = 0.9927. Temnothorax crasecundus sp. n. and Temnothorax crassispinus are parapatric species with a long contact zone stretching from the Peloponnisos peninsula across Bulgaria northeast to the southern Ukraine. There is no indication for occurrence of interspecifically mixed nests or intraspecific polymorphism. However, a significant reduction of interspecific morphological distance at sites with syntopic occurrence of both species indicates local hybridization. The results are discussed within the context of the Pragmatic Species Concept of Seifert (2014). The taxonomic description and a differential diagnosis of Temnothorax crasecundus sp. n. are given. PMID:25685016

Multi-granularity Bandwidth Allocation for Large-Scale WDM/TDM PON

NASA Astrophysics Data System (ADS)

Gao, Ziyue; Gan, Chaoqin; Ni, Cuiping; Shi, Qiongling

2017-12-01

WDM (wavelength-division multiplexing)/TDM (time-division multiplexing) PON (passive optical network) is being viewed as a promising solution for delivering multiple services and applications, such as high-definition video, video conference and data traffic. Considering the real-time transmission, QoS (quality of services) requirements and differentiated services model, a multi-granularity dynamic bandwidth allocation (DBA) in both domains of wavelengths and time for large-scale hybrid WDM/TDM PON is proposed in this paper. The proposed scheme achieves load balance by using the bandwidth prediction. Based on the bandwidth prediction, the wavelength assignment can be realized fairly and effectively to satisfy the different demands of various classes. Specially, the allocation of residual bandwidth further augments the DBA and makes full use of bandwidth resources in the network. To further improve the network performance, two schemes named extending the cycle of one free wavelength (ECoFW) and large bandwidth shrinkage (LBS) are proposed, which can prevent transmission from interruption when the user employs more than one wavelength. The simulation results show the effectiveness of the proposed scheme.

Differential responses of production and respiration to temperature and moisture drive the carbon balance across a climatic gradient in New Mexico

Treesearch

Kristina J. Anderson-Teixeira; John P. Delong; Andrew M. Fox; Daniel A. Brese; Marcy E. Litvak

2011-01-01

Southwestern North America faces an imminent transition to a warmer, more arid climate, and it is critical to understand how these changes will affect the carbon balance of southwest ecosystems. In order to test our hypothesis that differential responses of production and respiration to temperature and moisture shape the carbon balance across a range of spatio-temporal...

Sex allocation and secondary sex ratio in Cuban boa ( Chilabothrus angulifer): mother's body size affects the ratio between sons and daughters

NASA Astrophysics Data System (ADS)

Frynta, Daniel; Vejvodová, Tereza; Šimková, Olga

2016-06-01

Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (˜200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.

Sex allocation and secondary sex ratio in Cuban boa (Chilabothrus angulifer): mother's body size affects the ratio between sons and daughters.

PubMed

Frynta, Daniel; Vejvodová, Tereza; Šimková, Olga

2016-06-01

Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (∼200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.

Do plants adjust their sex allocation and secondary sexual morphology in response to their neighbours?

PubMed Central

Vilas, Julia Sánchez; Pannell, John R.

2012-01-01

Background and aims Changes in the sex allocation (i.e. in pollen versus seed production) of hermaphroditic plants often occur in response to the environment. In some homosporous ferns, gametophytes choose their gender in response to chemical cues sent by neighbours, such that spores develop as male gametophytes if they perceive a female or hermaphrodite nearby. Here it is considered whether a similar process might occur in the androdioecious angiosperm species Mercurialis annua, in which males co-occur with hermaphrodites; previous work on a Spanish population of M. annua found that individuals were more likely to develop as males at high density. Methods Using a novel approach to treat plants with leachate from pots containing males or hermaphrodites of M. annua, the hypothesis that individuals assess their mating opportunities, and adjust their sex expression accordingly, was tested through an exchange of chemical cues through the soil. Key Results For the population under study, from Morocco, no evidence was found for soil-signal-dependent sex expression: neither sex ratios nor sex allocation differed among experimental treatments. Conclusions The results imply either that the Moroccan population under study behaves differently from that previously studied in Spain (pointing to potential geographical variation in plasticity for sex expression), or that our method failed to capture the signals used by M. annua for adjustment of sex expression. PMID:22899829

Unicorns do exist: a tutorial on "proving" the null hypothesis.

PubMed

Streiner, David L

2003-12-01

Introductory statistics classes teach us that we can never prove the null hypothesis; all we can do is reject or fail to reject it. However, there are times when it is necessary to try to prove the nonexistence of a difference between groups. This most often happens within the context of comparing a new treatment against an established one and showing that the new intervention is not inferior to the standard. This article first outlines the logic of "noninferiority" testing by differentiating between the null hypothesis (that which we are trying to nullify) and the "nill" hypothesis (there is no difference), reversing the role of the null and alternate hypotheses, and defining an interval within which groups are said to be equivalent. We then work through an example and show how to calculate sample sizes for noninferiority studies.

Testing the Münch hypothesis of long distance phloem transport in plants

PubMed Central

Knoblauch, Michael; Knoblauch, Jan; Mullendore, Daniel L; Savage, Jessica A; Babst, Benjamin A; Beecher, Sierra D; Dodgen, Adam C; Jensen, Kaare H; Holbrook, N Michele

2016-01-01

Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for the Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues. DOI: http://dx.doi.org/10.7554/eLife.15341.001 PMID:27253062

Territory Quality and Plumage Morph Predict Offspring Sex Ratio Variation in a Raptor

PubMed Central

Chakarov, Nayden; Pauli, Martina; Mueller, Anna-Katharina; Potiek, Astrid; Grünkorn, Thomas; Dijkstra, Cor; Krüger, Oliver

2015-01-01

Parents may adapt their offspring sex ratio in response to their own phenotype and environmental conditions. The most significant causes for adaptive sex-ratio variation might express themselves as different distributions of fitness components between sexes along a given variable. Several causes for differential sex allocation in raptors with reversed sexual size dimorphism have been suggested. We search for correlates of fledgling sex in an extensive dataset on common buzzards Buteo buteo, a long-lived bird of prey. Larger female offspring could be more resource-demanding and starvation-prone and thus the costly sex. Prominent factors such as brood size and laying date did not predict nestling sex. Nonetheless, lifetime sex ratio (LSR, potentially indicative of individual sex allocation constraints) and overall nestling sex were explained by territory quality with more females being produced in better territories. Additionally, parental plumage morphs and the interaction of morph and prey abundance tended to explain LSR and nestling sex, indicating local adaptation of sex allocation However, in a limited census of nestling mortality, not females but males tended to die more frequently in prey-rich years. Also, although females could have potentially longer reproductive careers, a subset of our data encompassing full individual life histories showed that longevity and lifetime reproductive success were similarly distributed between the sexes. Thus, a basis for adaptive sex allocation in this population remains elusive. Overall, in common buzzards most major determinants of reproductive success appeared to have no effect on sex ratio but sex allocation may be adapted to local conditions in morph-specific patterns. PMID:26445010

Rawlsian maximin rule operates as a common cognitive anchor in distributive justice and risky decisions

PubMed Central

Kameda, Tatsuya; Inukai, Keigo; Higuchi, Satomi; Ogawa, Akitoshi; Kim, Hackjin; Matsuda, Tetsuya; Sakagami, Masamichi

2016-01-01

Distributive justice concerns the moral principles by which we seek to allocate resources fairly among diverse members of a society. Although the concept of fair allocation is one of the fundamental building blocks for societies, there is no clear consensus on how to achieve “socially just” allocations. Here, we examine neurocognitive commonalities of distributive judgments and risky decisions. We explore the hypothesis that people’s allocation decisions for others are closely related to economic decisions for oneself at behavioral, cognitive, and neural levels, via a concern about the minimum, worst-off position. In a series of experiments using attention-monitoring and brain-imaging techniques, we investigated this “maximin” concern (maximizing the minimum possible payoff) via responses in two seemingly disparate tasks: third-party distribution of rewards for others, and choosing gambles for self. The experiments revealed three robust results: (i) participants’ distributive choices closely matched their risk preferences—“Rawlsians,” who maximized the worst-off position in distributions for others, avoided riskier gambles for themselves, whereas “utilitarians,” who favored the largest-total distributions, preferred riskier but more profitable gambles; (ii) across such individual choice preferences, however, participants generally showed the greatest spontaneous attention to information about the worst possible outcomes in both tasks; and (iii) this robust concern about the minimum outcomes was correlated with activation of the right temporoparietal junction (RTPJ), the region associated with perspective taking. The results provide convergent evidence that social distribution for others is psychologically linked to risky decision making for self, drawing on common cognitive–neural processes with spontaneous perspective taking of the worst-off position. PMID:27688764

Commentary: "re-programming or selecting adult stem cells?".

PubMed

Trosko, James E

2008-01-01

The recent observations that embryonic stemness-associated genes could assist in the "de-differentiation" of adult skin fibroblast cells to "embryonic-like stem cells", using the "somatic cell nuclear transfer" techniques, have been interpreted as indicating a "re-programming" of genes. These reports have demonstrated a "proof of principle" approach to by-pass many, but not all, of the ethical, scientific and medical limitations of the "therapeutic cloning" of embryonic stem cells from embryos. However, while the interpretation that real "re-programming" of all those somatic fibroblastic differentiation genes might be correct, there does exists an alternative hypothesis of these exciting results. Based on the fact that multipotent adult stem cells exist in most, if not all, adult organs, the possibility exists that all these recent "re-programming" results, using the somatic nuclear transfer techniques, actually were the results of transferred rare nuclear material from the adult stem cells residing in the skin of the mouse, monkey and human samples. An examination of the rationale for this challenging hypothesis has been drawn from the hypothesis of the "stem cell theory of cancer", as well as from the field of human adult stem cells research.

Implementation of an experimental program to investigate the performance characteristics of OMEGA navigation

NASA Technical Reports Server (NTRS)

Baxa, E. G., Jr.

1974-01-01

A theoretical formulation of differential and composite OMEGA error is presented to establish hypotheses about the functional relationships between various parameters and OMEGA navigational errors. Computer software developed to provide for extensive statistical analysis of the phase data is described. Results from the regression analysis used to conduct parameter sensitivity studies on differential OMEGA error tend to validate the theoretically based hypothesis concerning the relationship between uncorrected differential OMEGA error and receiver separation range and azimuth. Limited results of measurement of receiver repeatability error and line of position measurement error are also presented.

Journal news

USGS Publications Warehouse

Conroy, M.J.; Samuel, M.D.; White, Joanne C.

1995-01-01

Statistical power (and conversely, Type II error) is often ignored by biologists. Power is important to consider in the design of studies, to ensure that sufficient resources are allocated to address a hypothesis under examination. Deter- mining appropriate sample size when designing experiments or calculating power for a statistical test requires an investigator to consider the importance of making incorrect conclusions about the experimental hypothesis and the biological importance of the alternative hypothesis (or the biological effect size researchers are attempting to measure). Poorly designed studies frequently provide results that are at best equivocal, and do little to advance science or assist in decision making. Completed studies that fail to reject Ho should consider power and the related probability of a Type II error in the interpretation of results, particularly when implicit or explicit acceptance of Ho is used to support a biological hypothesis or management decision. Investigators must consider the biological question they wish to answer (Tacha et al. 1982) and assess power on the basis of biologically significant differences (Taylor and Gerrodette 1993). Power calculations are somewhat subjective, because the author must specify either f or the minimum difference that is biologically important. Biologists may have different ideas about what values are appropriate. While determining biological significance is of central importance in power analysis, it is also an issue of importance in wildlife science. Procedures, references, and computer software to compute power are accessible; therefore, authors should consider power. We welcome comments or suggestions on this subject.

Goal direction and effectiveness, emotional maturity, and nuclear family functioning.

PubMed

Klever, Phillip

2009-07-01

Differentiation of self, a cornerstone concept in Bowen theory, has a profound influence over time on the functioning of the individual and his or her family unit. This 5-year longitudinal study tested this hypothesis with 50 developing nuclear families. The dimensions of differentiation of self that were examined were goal direction and effectiveness and emotional maturity. A qualitative analysis of participants' goals demonstrated that couples with higher functioning developing nuclear families, when compared with couples with lower functioning families, placed more emphasis on family goals, had more balance between family and personal goals, and pursued more goals over the 5 years. The quantitative analysis supported the hypothesis that goal effectiveness and emotional maturity influenced variation in nuclear family functioning. In addition, couple goal effectiveness and emotional maturity were associated with nuclear family functioning more strongly than individual goal effectiveness and emotional maturity were associated with individual functioning.

Feeling Blue or Turquoise? Emotional Differentiation in Major Depressive Disorder

PubMed Central

Demiralp, Emre; Thompson, Renee J.; Mata, Jutta; Jaeggi, Susanne M.; Buschkuehl, Martin; Barrett, Lisa Feldman; Ellsworth, Phoebe C.; Demiralp, Metin; Hernandez-Garcia, Luis; Deldin, Patricia J.; Gotlib, Ian H.; Jonides, John

2014-01-01

Some individuals have very specific and differentiated emotional experiences, such as anger, shame, excitement, and happiness, whereas others have more general affective experiences of pleasure or discomfort that are not as highly differentiated. Considering that individuals with major depressive disorder (MDD) have cognitive deficits for negative information, we predicted that people with MDD would have less differentiated negative emotional experiences than would healthy people. To test this hypothesis, we assessed participants' emotional experiences using a 7-day experience-sampling protocol. Depression was assessed using structured clinical interviews and the Beck Depression Inventory-II. As predicted, individuals with MDD had less differentiated emotional experiences than did healthy participants, but only for negative emotions. These differences were above and beyond the effects of emotional intensity and variability. PMID:23070307

Differential parenting and children's behavioral problems: curvilinear associations and mother-father combined effects.

PubMed

Meunier, Jean Christophe; Bisceglia, Rossana; Jenkins, Jennifer M

2012-07-01

In this study the associations between mothers' and fathers' differential parenting and children's oppositional and emotional problems were examined. A curvilinear relationship between differential parenting and children's outcomes was hypothesized, as well as the combined effect of mothers' and fathers' parenting. Data came from a community sample of 599 two-parent families with multiple children per family and were analyzed using a cross-classified multilevel model. Results showed that both family average parenting and differential parenting explained unique variance in children's outcomes. The curvilinear hypothesis was supported for oppositional behavior but not for emotional problems. The effects of mother and father positivity were found to be additive for both family average parenting and differential parenting, but for negativity there was evidence for multiplicative effects.

Threshold-dependent cooperativity of Pdx1 and Oc1 in pancreatic progenitors establishes competency for endocrine differentiation and β-cell function

PubMed Central

Wright, Christopher V.E.; Won, Kyoung-Jae

2016-01-01

Summary Pdx1 and Oc1 are co-expressed in multipotent pancreatic progenitors and regulate the pro-endocrine gene Neurog3. Their expression diverges in later organogenesis, with Oc1 absent from hormone+ cells and Pdx1 maintained in mature β cells. In a classical genetic test for cooperative functional interactions, we derived mice with combined Pdx1 and Oc1 heterozygosity. Endocrine development in double-heterozygous pancreata was normal at embryonic day (e)13.5, but defects in specification and differentiation were apparent at e15.5, the height of the second wave of differentiation. Pancreata from double heterozygotes showed alterations in the expression of genes crucial for β-cell development and function, decreased numbers and altered allocation of Neurog3-expressing endocrine progenitors, and defective endocrine differentiation. Defects in islet gene expression and β-cell function persisted in double heterozygous neonates. These results suggest that Oc1 and Pdx1 cooperate prior to their divergence, in pancreatic progenitors, to allow for proper differentiation and functional maturation of β cells. PMID:27292642

To P or Not to P: Backing Bayesian Statistics.

PubMed

Buchinsky, Farrel J; Chadha, Neil K

2017-12-01

In biomedical research, it is imperative to differentiate chance variation from truth before we generalize what we see in a sample of subjects to the wider population. For decades, we have relied on null hypothesis significance testing, where we calculate P values for our data to decide whether to reject a null hypothesis. This methodology is subject to substantial misinterpretation and errant conclusions. Instead of working backward by calculating the probability of our data if the null hypothesis were true, Bayesian statistics allow us instead to work forward, calculating the probability of our hypothesis given the available data. This methodology gives us a mathematical means of incorporating our "prior probabilities" from previous study data (if any) to produce new "posterior probabilities." Bayesian statistics tell us how confidently we should believe what we believe. It is time to embrace and encourage their use in our otolaryngology research.

Terror management and aggression: evidence that mortality salience motivates aggression against worldview-threatening others.

PubMed

McGregor, H A; Lieberman, J D; Greenberg, J; Solomon, S; Arndt, J; Simon, L; Pyszczynski, T

1998-03-01

The hypothesis that mortality salience (MS) motivates aggression against worldview-threatening others was tested in 4 studies. In Study 1, the experimenters induced participants to write about either their own death or a control topic, presented them with a target who either disparaged their political views or did not, and gave them the opportunity to choose the amount of hot sauce the target would have to consume. As predicted, MS participants allocated a particularly large amount of hot sauce to the worldview-threatening target. In Studies 2 and 3, the authors found that following MS induction, the opportunity to express a negative attitude toward the critical target eliminated aggression and the opportunity to aggress against the target eliminated derogation. This suggests that derogation and aggression are two alternative modes of responding to MS that serve the same psychological function. Finally, Study 4 showed that MS did not encourage aggression against a person who allocated unpleasant juice to the participant, supporting the specificity of MS-induced aggression to worldview-threatening others.

Genetic, morphological, and spectral characterization of relictual Niobrara River hybrid aspens (Populus × smithii).

PubMed

Deacon, Nicholas John; Grossman, Jake Joseph; Schweiger, Anna Katharina; Armour, Isabella; Cavender-Bares, Jeannine

2017-12-01

Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to morphological differences from nearby remnant Populus tremuloides populations. Pleistocene hybridization between P. tremuloides and P. grandidentata has been proposed, but the nearest P. grandidentata populations are currently several hundred kilometers east. We tested the hybrid-origin hypothesis using genetic data and characterized putative hybrids phenotypically. We compared nuclear microsatellite loci and chloroplast sequences of Niobrara River aspens to their putative parental species. Parental species and putative hybrids were also grown in a common garden for phenotypic comparison. On the common garden plants, we measured leaf morphological traits and leaf-level spectral reflectance profiles, from which chemical traits were derived. The genetic composition of the three unique Niobrara aspen genotypes is consistent with the hybridization hypothesis and with maternal chloroplast inheritance from P. grandidentata . Leaf margin dentition and abaxial pubescence differentiated taxa, with the hybrids showing intermediate values. Spectral profiles allowed statistical separation of taxa in short-wave infrared wavelengths, with hybrids showing intermediate values, indicating that traits associated with internal structure of leaves and water absorption may vary among taxa. However, reflectance values in the visible region did not differentiate taxa, indicating that traits related to pigments are not differentiated. Both genetic and phenotypic results support the hypothesis of a hybrid origin for these genetically unique aspens. However, low genetic diversity and ongoing ecological and climatic threats to the hybrid taxon present a challenge for conservation of these relictual boreal communities. © 2017 Botanical Society of America.

Is council tax valuation band a predictor of mortality?

PubMed Central

Beale, Norman R; Taylor, Gordon J; Straker-Cook, Dawn MK

2002-01-01

Background All current UK indices of socio-economic status have inherent problems, especially those used to govern resource allocation to the health sphere. The search for improved markers continues: this study proposes and tests the possibility that Council Tax Valuation Band (CTVB) might match requirements. Presentation of the hypothesis To determine if there is an association between CTVB of final residence and mortality risk using the death registers of a UK general practice. Testing the hypothesis Standardised death rates and odds ratios (ORs) for groups defined by CTVB of dwelling (A – H) were calculated using one in four denominator samples from the practice lists. Analyses were repeated three times – between number of deaths and CTVB of residence of deceased 1992 – 1994 inclusive, 1995 – 1997 inc., 1998 – 2000 inc. In 856 deaths there were consistent and significant differences in death rates between CTVBs: above average for bands A and B residents; below average for other band residents. There were significantly higher ORs for A, B residents who were female and who died prematurely (before average group life expectancy). Implications of the hypothesis CTVB of final residence appears to be a proxy marker of mortality risk and could be a valuable indicator of health needs resource at household level. It is worthy of further exploration. PMID:12207828

Time is up: increasing shadow price of time in primary-care office visits.

PubMed

Tai-Seale, Ming; McGuire, Thomas

2012-04-01

A physician's own time is a scarce resource in primary care, and the physician must constantly evaluate the gain from spending more time with the current patient against moving to address the health-care needs of the next. We formulate and test two alternative hypotheses. The first hypothesis is based on the premise that with time so scarce, physicians equalize the marginal value of time across patients. The second, alternative hypothesis states that physicians allocate the same time to each patient, regardless of how much the patient benefits from the time at the margin. For our empirical work, we examine the presence of a sharply increasing subjective shadow price of time around the 'target' time using video recordings of 385 visits by elderly patients to their primary care physician. We structure the data at the 'topic' level and find evidence consistent with the alternative hypothesis. Specifically, time elapsed within a visit is a very strong determinant of the current topic being the 'last topic'. This finding implies the physician's shadow price of time is rising during the course of a visit. We consider whether dislodging a target-time mentality from physicians (and patients) might contribute to more productive primary care practice. Copyright © 2011 John Wiley & Sons, Ltd.

The allocation of attention and working memory in visual crowding.

PubMed

Bacigalupo, Felix; Luck, Steven J

2015-06-01

When the distance between a visual target and nearby flankers falls below a critical distance, target discrimination declines precipitously. This is called "crowding." Many researchers have proposed that selective attention plays a role in crowding. However, although some research has examined the effects of directing attention toward versus away from the targets, no previous research has assessed how attentional allocation varies as a function of target-flanker distance in crowding. Here, we used ERPs to assess the operation of attention during crowding, focusing on the attention-related N2pc component. We used a typical crowding task in which participants were asked to report the category (vowel/consonant) of a lateralized target letter flanked by distractor letters at different distances. We tested the hypothesis that attention fails when the target-flanker distance becomes too small for attention to operate effectively. Consistent with this hypothesis, we found that N2pc amplitude was maximal at intermediate target-flanker distances and decreased substantially when crowding became severe. In addition, we examined the sustained posterior contralateral negativity (SPCN), which reflects the amount of information being maintained in working memory. Unlike the N2pc component, the SPCN increased in amplitude at small target-flanker distances, suggesting that observers stored information about the target and flankers in working memory when attention failed to select the target. Together, the N2pc and SPCN results suggest that attention and working memory play distinctive roles in crowding: Attention operates to minimize interference from the flankers at intermediate target-flanker distances, whereas working memory may be recruited when attention fails to select the target at small target-flanker distances.

l-Theanine and caffeine improve target-specific attention to visual stimuli by decreasing mind wandering: a human functional magnetic resonance imaging study.

PubMed

Kahathuduwa, Chanaka N; Dhanasekara, Chathurika S; Chin, Shao-Hua; Davis, Tyler; Weerasinghe, Vajira S; Dassanayake, Tharaka L; Binks, Martin

2018-01-01

Oral intake of l-theanine and caffeine supplements is known to be associated with faster stimulus discrimination, possibly via improving attention to stimuli. We hypothesized that l-theanine and caffeine may be bringing about this beneficial effect by increasing attention-related neural resource allocation to target stimuli and decreasing deviation of neural resources to distractors. We used functional magnetic resonance imaging (fMRI) to test this hypothesis. Solutions of 200mg of l-theanine, 160mg of caffeine, their combination, or the vehicle (distilled water; placebo) were administered in a randomized 4-way crossover design to 9 healthy adult men. Sixty minutes after administration, a 20-minute fMRI scan was performed while the subjects performed a visual color stimulus discrimination task. l-Theanine and l-theanine-caffeine combination resulted in faster responses to targets compared with placebo (∆=27.8milliseconds, P=.018 and ∆=26.7milliseconds, P=.037, respectively). l-Theanine was associated with decreased fMRI responses to distractor stimuli in brain regions that regulate visual attention, suggesting that l-theanine may be decreasing neural resource allocation to process distractors, thus allowing to attend to targets more efficiently. l-Theanine-caffeine combination was associated with decreased fMRI responses to target stimuli as compared with distractors in several brain regions that typically show increased activation during mind wandering. Factorial analysis suggested that l-theanine and caffeine seem to have a synergistic action in decreasing mind wandering. Therefore, our hypothesis is that l-theanine and caffeine may be decreasing deviation of attention to distractors (including mind wandering); thus, enhancing attention to target stimuli was confirmed. Copyright © 2017 Elsevier Inc. All rights reserved.

Biofunctional Understanding and Conceptual Control: Searching for Systematic Consensus in Systemic Cohesion

PubMed Central

Iran-Nejad, Asghar; Bordbar, Fareed

2017-01-01

For first generation scientists after the cognitive revolution, knowers were in active control over all (stages of) information processing. Then, following a decade of transition shaped by intense controversy, embodied cognition emerged and suggested sources of control other than those implied by metaphysical information processing. With a thematic focus on embodiment science and an eye toward systematic consensus in systemic cohesion, the present study explores the roles of biofunctional and conceptual control processes in the wholetheme spiral of biofunctional understanding (see Iran-Nejad and Irannejad, 2017b, Figure 1). According to this spiral, each of the two kinds of understanding has its own unique set of knower control processes. For conceptual understanding (CU), knowers have deliberate attention-allocation control over their first-person “knowthat” and “knowhow” content combined as mutually coherent corequisites. For biofunctional understanding (BU), knowers have attention-allocation control only over their knowthat content but knowhow control content is ordinarily conspicuously absent. To test the hypothesis of differences in the manner of control between CU and BU, participants in two experiments read identical-format statements for internal consistency, as response time was recorded. The results of Experiment 1 supported the hypothesis of differences in the manner of control between the two types of control processes; and Experiment 2 confirmed the results of Experiment 1. These findings are discussed in terms of the predicted differences between BU and CU control processes, their roles in regulating the physically unobservable flow of systemic cohesion in the wholetheme spiral, and a proposal for systematic consensus in systemic cohesion to serve as the second guiding principle in biofunctional embodiment science next to physical science’s first guiding principle of systematic observation. PMID:29114235

Refuge quality to cope with UV radiation affects energy allocation in an intertidal fish.

PubMed

Vargas, Juan; Duarte, Cristian; Galban-Malagón, Cristóbal; Roberto García-Huidobro, M; Aldana, Marcela; Pulgar, José

2018-05-01

Ultraviolet (UV) radiation is a primary environmental stressor for marine species inhabiting intertidal pools. Thus, the use of microhabitats as refuges is key to protect organisms against this stressor. In this study, we compared the quality of rocky and algae as refuges for the intertidal fish Girella laevifrons exposed to UV radiation. Refuge quality was studied by evaluating oxygen consumption and weight gain in control and UV-exposed fish. Rocky-refuge fish consumed less oxygen and gained significantly more weight than algal-refuge fish. The obtained results support the importance of refuge quality on energetic balance of intertidal organisms, where energy can be differentially allocated towards key life processes such as protection/repair or growth. Energy trade-offs need to be considered in research concerning animals inhabiting stressful habitats. Copyright © 2018. Published by Elsevier Ltd.

Consumer-Resource Dynamics: Quantity, Quality, and Allocation

PubMed Central

Getz, Wayne M.; Owen-Smith, Norman

2011-01-01

Background The dominant paradigm for modeling the complexities of interacting populations and food webs is a system of coupled ordinary differential equations in which the state of each species, population, or functional trophic group is represented by an aggregated numbers-density or biomass-density variable. Here, using the metaphysiological approach to model consumer-resource interactions, we formulate a two-state paradigm that represents each population or group in a food web in terms of both its quantity and quality. Methodology and Principal Findings The formulation includes an allocation function controlling the relative proportion of extracted resources to increasing quantity versus elevating quality. Since lower quality individuals senesce more rapidly than higher quality individuals, an optimal allocation proportion exists and we derive an expression for how this proportion depends on population parameters that determine the senescence rate, the per-capita mortality rate, and the effects of these rates on the dynamics of the quality variable. We demonstrate that oscillations do not arise in our model from quantity-quality interactions alone, but require consumer-resource interactions across trophic levels that can be stabilized through judicious resource allocation strategies. Analysis and simulations provide compelling arguments for the necessity of populations to evolve quality-related dynamics in the form of maternal effects, storage or other appropriate structures. They also indicate that resource allocation switching between investments in abundance versus quality provide a powerful mechanism for promoting the stability of consumer-resource interactions in seasonally forcing environments. Conclusions/Significance Our simulations show that physiological inefficiencies associated with this switching can be favored by selection due to the diminished exposure of inefficient consumers to strong oscillations associated with the well-known paradox of enrichment. Also our results demonstrate how allocation switching can explain observed growth patterns in experimental microbial cultures and discuss how our formulation can address questions that cannot be answered using the quantity-only paradigms that currently predominate. PMID:21283752

Renal Transplants from Older Deceased Donors: Use of Preimplantation Biopsy and Differential Allocation to Dual or Single Kidney Transplant according to Histological Score Has No Advantages over Allocation to Single Kidney Transplant by Simple Clinical Indication.

PubMed

Casati, Costanza; Colombo, Valeriana Giuseppina; Perrino, Marialuisa; Rossetti, Ornella Marina; Querques, Marialuisa; Giacomoni, Alessandro; Binaggia, Agnese; Colussi, Giacomo

2018-01-01

Grafts from elderly donors (ECD) are increasingly allocated to single (SKT) or dual (DKT) kidney transplantation according to biopsy score. Indications and benefits of either procedure lack universal agreement. A total of 302 ECD-transplants in period from Jan 1, 2000, to Dec 31, 2015, were allocated to SKT (SKT pre ) on clinical grounds alone (before Dec 2010, pre-DKT era, n = 170) or according to a clinical-histological protocol (after Dec 2010, DKT era, n = 132) to DKT ( n = 48), SKT biopsy-based protocol ("high-risk", SKT hr , n = 51), or SKT clinically based protocol ("low-risk", SKT lr , n = 33). Graft and patient survival were compared between the two periods and between different transplant categories. Graft and overall survival in recipients from ECD in pre-DKT and DKT era did not differ (5-year graft survival 87.7% and 84.2%, resp.); equal survival in the 2 ECD periods was shown in both donor age ranges of 60-69 and >70-years, and in low-risk or high-risk ECD categories. Within the DKT protocol SKT hr showed worst graft and overall survival in the 60-69 donor age range; DKT did not result in significantly better outcome than SKT from ECD in either era. One-year posttransplant creatinine clearance in recipients did not differ between any ECD transplant category. At 3 and 5 years after transplantation there were significantly higher total dialysis-free recipient life years from an equal donor number in the pre-DKT era than in the DKT protocol. Use of a biopsy-based protocol to allocate grafts from aged donors to SKT or DKT did not result in better short term graft survival than a clinically based protocol with allocation only to SKT and reduced overall recipient dialysis-free life years in time.

Renal Transplants from Older Deceased Donors: Use of Preimplantation Biopsy and Differential Allocation to Dual or Single Kidney Transplant according to Histological Score Has No Advantages over Allocation to Single Kidney Transplant by Simple Clinical Indication

PubMed Central

Casati, Costanza; Colombo, Valeriana Giuseppina; Perrino, Marialuisa; Rossetti, Ornella Marina; Querques, Marialuisa; Giacomoni, Alessandro; Binaggia, Agnese

2018-01-01

Background Grafts from elderly donors (ECD) are increasingly allocated to single (SKT) or dual (DKT) kidney transplantation according to biopsy score. Indications and benefits of either procedure lack universal agreement. Methods A total of 302 ECD-transplants in period from Jan 1, 2000, to Dec 31, 2015, were allocated to SKT (SKTpre) on clinical grounds alone (before Dec 2010, pre-DKT era, n = 170) or according to a clinical-histological protocol (after Dec 2010, DKT era, n = 132) to DKT (n = 48), SKT biopsy-based protocol (“high-risk”, SKThr, n = 51), or SKT clinically based protocol (“low-risk”, SKTlr, n = 33). Graft and patient survival were compared between the two periods and between different transplant categories. Results Graft and overall survival in recipients from ECD in pre-DKT and DKT era did not differ (5-year graft survival 87.7% and 84.2%, resp.); equal survival in the 2 ECD periods was shown in both donor age ranges of 60–69 and >70-years, and in low-risk or high-risk ECD categories. Within the DKT protocol SKThr showed worst graft and overall survival in the 60–69 donor age range; DKT did not result in significantly better outcome than SKT from ECD in either era. One-year posttransplant creatinine clearance in recipients did not differ between any ECD transplant category. At 3 and 5 years after transplantation there were significantly higher total dialysis-free recipient life years from an equal donor number in the pre-DKT era than in the DKT protocol. Conclusions Use of a biopsy-based protocol to allocate grafts from aged donors to SKT or DKT did not result in better short term graft survival than a clinically based protocol with allocation only to SKT and reduced overall recipient dialysis-free life years in time. PMID:29862061

Importance of whole-plant biomass allocation and reproductive timing to habitat differentiation across the North American sunflowers.

PubMed

Mason, Chase M; Goolsby, Eric W; Davis, Kaleigh E; Bullock, Devon V; Donovan, Lisa A

2017-05-01

Trait-based plant ecology attempts to use small numbers of functional traits to predict plant ecological strategies. However, a major gap exists between our understanding of organ-level ecophysiological traits and our understanding of whole-plant fitness and environmental adaptation. In this gap lie whole-plant organizational traits, including those that describe how plant biomass is allocated among organs and the timing of plant reproduction. This study explores the role of whole-plant organizational traits in adaptation to diverse environments in the context of life history, growth form and leaf economic strategy in a well-studied herbaceous system. A phylogenetic comparative approach was used in conjunction with common garden phenotyping to assess the evolution of biomass allocation and reproductive timing across 83 populations of 27 species of the diverse genus Helianthus (the sunflowers). Broad diversity exists among species in both relative biomass allocation and reproductive timing. Early reproduction is strongly associated with resource-acquisitive leaf economic strategy, while biomass allocation is less integrated with either reproductive timing or leaf economics. Both biomass allocation and reproductive timing are strongly related to source site environmental characteristics, including length of the growing season, temperature, precipitation and soil fertility. Herbaceous taxa can adapt to diverse environments in many ways, including modulation of phenology, plant architecture and organ-level ecophysiology. Although leaf economic strategy captures one key aspect of plant physiology, on their own leaf traits are not particularly predictive of ecological strategies in Helianthus outside of the context of growth form, life history and whole-plant organization. These results highlight the importance of including data on whole-plant organization alongside organ-level ecophysiological traits when attempting to bridge the gap between functional traits and plant fitness and environmental adaptation. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Importance of whole-plant biomass allocation and reproductive timing to habitat differentiation across the North American sunflowers

PubMed Central

Goolsby, Eric W.; Davis, Kaleigh E.; Bullock, Devon V.; Donovan, Lisa A.

2017-01-01

Abstract Background and Aims Trait-based plant ecology attempts to use small numbers of functional traits to predict plant ecological strategies. However, a major gap exists between our understanding of organ-level ecophysiological traits and our understanding of whole-plant fitness and environmental adaptation. In this gap lie whole-plant organizational traits, including those that describe how plant biomass is allocated among organs and the timing of plant reproduction. This study explores the role of whole-plant organizational traits in adaptation to diverse environments in the context of life history, growth form and leaf economic strategy in a well-studied herbaceous system. Methods A phylogenetic comparative approach was used in conjunction with common garden phenotyping to assess the evolution of biomass allocation and reproductive timing across 83 populations of 27 species of the diverse genus Helianthus (the sunflowers). Key Results Broad diversity exists among species in both relative biomass allocation and reproductive timing. Early reproduction is strongly associated with resource-acquisitive leaf economic strategy, while biomass allocation is less integrated with either reproductive timing or leaf economics. Both biomass allocation and reproductive timing are strongly related to source site environmental characteristics, including length of the growing season, temperature, precipitation and soil fertility. Conclusions Herbaceous taxa can adapt to diverse environments in many ways, including modulation of phenology, plant architecture and organ-level ecophysiology. Although leaf economic strategy captures one key aspect of plant physiology, on their own leaf traits are not particularly predictive of ecological strategies in Helianthus outside of the context of growth form, life history and whole-plant organization. These results highlight the importance of including data on whole-plant organization alongside organ-level ecophysiological traits when attempting to bridge the gap between functional traits and plant fitness and environmental adaptation. PMID:28203721

Random Forest Segregation of Drug Responses May Define Regions of Biological Significance

PubMed Central

Bukhari, Qasim; Borsook, David; Rudin, Markus; Becerra, Lino

2016-01-01

The ability to assess brain responses in unsupervised manner based on fMRI measure has remained a challenge. Here we have applied the Random Forest (RF) method to detect differences in the pharmacological MRI (phMRI) response in rats to treatment with an analgesic drug (buprenorphine) as compared to control (saline). Three groups of animals were studied: two groups treated with different doses of the opioid buprenorphine, low (LD), and high dose (HD), and one receiving saline. PhMRI responses were evaluated in 45 brain regions and RF analysis was applied to allocate rats to the individual treatment groups. RF analysis was able to identify drug effects based on differential phMRI responses in the hippocampus, amygdala, nucleus accumbens, superior colliculus, and the lateral and posterior thalamus for drug vs. saline. These structures have high levels of mu opioid receptors. In addition these regions are involved in aversive signaling, which is inhibited by mu opioids. The results demonstrate that buprenorphine mediated phMRI responses comprise characteristic features that allow a supervised differentiation from placebo treated rats as well as the proper allocation to the respective drug dose group using the RF method, a method that has been successfully applied in clinical studies. PMID:27014046

Zooming in on the cause of the perceptual load effect in the go/no-go paradigm.

PubMed

Chen, Zhe; Cave, Kyle R

2016-08-01

Perceptual load theory (Lavie, 2005) claims that attentional capacity that is not used for the current task is allocated to irrelevant distractors. It predicts that if the attentional demands of the current task are high, distractor interference will be low. One particularly powerful demonstration of perceptual load effects on distractor processing relies on a go/no-go cue that is interpreted by either simple feature detection or feature conjunction (Lavie, 1995). However, a possible alternative interpretation of these effects is that the differential degree of distractor processing is caused by how broadly attention is allocated (attentional zoom) rather than to perceptual load. In 4 experiments, we show that when stimuli are arranged to equalize the extent of spatial attention across conditions, distractor interference varies little whether cues are defined by a simple feature or a conjunction, and that the typical perceptual load effect emerges only when attentional zoom can covary with perceptual load. These results suggest that attentional zoom can account for the differential degree of distractor processing traditionally attributed to perceptual load in the go/no-go paradigm. They also provide new insight into how different factors interact to control distractor interference. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Interannual variability of growth and reproduction in Bursera simaruba: the role of allometry and resource variability.

PubMed

Hulshof, Catherine M; Stegen, James C; Swenson, Nathan G; Enquist, Carolyn A F; Enquist, Brian J

2012-01-01

Plants are expected to differentially allocate resources to reproduction, growth, and survival in order to maximize overall fitness. Life history theory predicts that the allocation of resources to reproduction should occur at the expense of vegetative growth. Although it is known that both organism size and resource availability can influence life history traits, few studies have addressed how size dependencies of growth and reproduction and variation in resource supply jointly affect the coupling between growth and reproduction. In order to understand the relationship between growth and reproduction in the context of resource variability, we utilize a long-term observational data set consisting of 670 individual trees over a 10-year period within a local population of Bursera simaruba (L.) Sarg. We (1) quantify the functional form and variability in the growth-reproduction relationship at the population and individual-tree level and (2) develop a theoretical framework to understand the allometric dependence of growth and reproduction. Our findings suggest that the differential responses of allometric growth and reproduction to resource availability, both between years and between microsites, underlie the apparent relationship between growth and reproduction. Finally, we offer an alternative approach for quantifying the relationship between growth and reproduction that accounts for variation in allometries.

Determinants of intra-household food allocation between adults in South Asia - a systematic review.

PubMed

Harris-Fry, Helen; Shrestha, Niva; Costello, Anthony; Saville, Naomi M

2017-06-21

Nutrition interventions, often delivered at the household level, could increase their efficiency by channelling resources towards pregnant or lactating women, instead of leaving resources to be disproportionately allocated to traditionally favoured men. However, understanding of how to design targeted nutrition programs is limited by a lack of understanding of the factors affecting the intra-household allocation of food. We systematically reviewed literature on the factors affecting the allocation of food to adults in South Asian households (in Afghanistan, Bangladesh, Bhutan, India, Islamic Republic of Iran, Maldives, Nepal, Pakistan, Sri Lanka) and developed a framework of food allocation determinants. Two reviewers independently searched and filtered results from PubMed, Web of Knowledge and Scopus databases by using pre-defined search terms and hand-searching the references from selected papers. Determinants were extracted, categorised into a framework, and narratively described. We used adapted Downs and Black and Critical Appraisal Skills Programme checklists to assess the quality of evidence. Out of 6928 retrieved studies we found 60 relevant results. Recent, high quality evidence was limited and mainly from Bangladesh, India and Nepal. There were no results from Iran, Afghanistan, Maldives, or Bhutan. At the intra-household level, food allocation was determined by relative differences in household members' income, bargaining power, food behaviours, social status, tastes and preferences, and interpersonal relationships. Household-level determinants included wealth, food security, occupation, land ownership, household size, religion / ethnicity / caste, education, and nutrition knowledge. In general, the highest inequity occurred in households experiencing severe or unexpected food insecurity, and also in better-off, high caste households, whereas poorer, low caste but not severely food insecure households were more equitable. Food allocation also varied regionally and seasonally. Program benefits may be differentially distributed within households of different socioeconomic status, and targeting of nutrition programs might be improved by influencing determinants that are amenable to change, such as food security, women's employment, or nutrition knowledge. Longitudinal studies in different settings could unravel causal effects. Conclusions are not generalizable to the whole South Asian region, and research is needed in many countries.

Do not Bet on the Unknown Versus Try to Find Out More: Estimation Uncertainty and “Unexpected Uncertainty” Both Modulate Exploration

PubMed Central

Payzan-LeNestour, Élise; Bossaerts, Peter

2012-01-01

Little is known about how humans solve the exploitation/exploration trade-off. In particular, the evidence for uncertainty-driven exploration is mixed. The current study proposes a novel hypothesis of exploration that helps reconcile prior findings that may seem contradictory at first. According to this hypothesis, uncertainty-driven exploration involves a dilemma between two motives: (i) to speed up learning about the unknown, which may beget novel reward opportunities; (ii) to avoid the unknown because it is potentially dangerous. We provide evidence for our hypothesis using both behavioral and simulated data, and briefly point to recent evidence that the brain differentiates between these two motives. PMID:23087606

Restrained Differential Growth: The Initiating Event of Adolescent Idiopathic Scoliosis?

PubMed

Crijns, Tom Joris; Stadhouder, Agnita; Smit, Theodoor Henri

2017-06-15

An experimental model study and a short review of literature. The purpose of this study was to explore a new hypothesis suggesting that the curvatures seen in adolescent idiopathic scoliosis (AIS) originate from restrained differential growth between the vertebral column and the surrounding musculo-ligamentary structures. Despite decades of research, there is no generally accepted theory on the physical origin of the severe spinal deformations seen in AIS. The prevailing theories tend to focus on left-right asymmetry, rotational instability, or the sagittal spinal profile in idiopathic scoliosis. We test our hypothesis with a physical model of the spine that simulates growth, counteracted by ligaments and muscles, modeled by tethers and springs. Growth of the spine is further restrained by an anterior band representing the thorax, the linea alba, and abdominal musculature. We also explore literature in search of molecular mechanisms that may induce differential growth. Differential growth in the restrained spine model first induces hypokyphosis and mild lateral bending of the thoracic spine, but then suddenly escalates into a scoliotic deformity, consistent with clinical observations of AIS. The band simulating the ventral structures of the body had a pivotal effect on sagittal curvature and the initiation of lateral bending and rotation. In literature, several molecular mechanisms were found that may explain the occurrence of differential growth between the spine and the musculo-ligamentary structures. While AIS is a three-dimensional deformation of the spine, it appears that restrained differential growth in the sagittal plane can result in lateral bending and rotation without a pre-existing left-right asymmetry. This supports the concept that AIS may result from a growth imbalance rather than a local anatomical defect. N/A.

Estimation of carbon allocation of Macauba palm (Acrocomia aculeata) - A new Brazilian biofuel alternative

NASA Astrophysics Data System (ADS)

Imbuzeiro, H. A.

2016-12-01

The Macauba palm (Acrocomia aculeata (Jacq.) Lood. ex Mart) is a native oil palm of the tropical America growing in anthropic areas, especially in grazing lands of Brazilian Cerrado. Macauba palm displays intense fruiting which results in high fruit and oil yield (3.0 - 6.0 ton/ha/year). The main Macauba palm differentials are: it is adapted to the environment with marked water restriction (1000 mm annual precipitation) which makes it resistant to drought and it does not compete with areas of rainforest; the oil is similar in composition to the African palm oil (Elaeis guineensis Jacq.) and can be used in several industrial applications such as biofuels, food, cosmetics, pharmaceutics and oil chemistry. Additionally, Macauba fruit processing generates several by-products like edible pulp bran, high-protein edible kernel bran, dense endocarp biomass, and husk biomass, all valuable products. Today, 172 million hectares of Brazilian land are used for grazing, of which 30 million hectares of these lands are degraded due to poor land use, 6 million in the state of Minas Gerais, in Brazil. Macauba could be cultivated in these degraded lands and is a candidate to become the main raw material for production of biokerosene. A new productive chain is forming in Brazil, the first commercial plantation of Macauba was implemented last year in Minas Gerais state and it is important to estimate the environmental impacts of this plantation, in terms of carbon (C) allocation. There is a lack of experimental data on Macauba carbon allocation and this study aimed to estimate the carbon allocation (leaves, stems and roots) of Macauba palm. The results suggest that Macauba palm is important in contributing to the carbon allocation and nutrient cycling.

[Changing the internal cost allocation (ICA) on DRG shares : Example of computed tomography in a university radiology setting].

PubMed

Wirth, K; Zielinski, P; Trinter, T; Stahl, R; Mück, F; Reiser, M; Wirth, S

2016-08-01

In hospitals, the radiological services provided to non-privately insured in-house patients are mostly distributed to requesting disciplines through internal cost allocation (ICA). In many institutions, computed tomography (CT) is the modality with the largest amount of allocation credits. The aim of this work is to compare the ICA to respective DRG (Diagnosis Related Groups) shares for diagnostic CT services in a university hospital setting. The data from four CT scanners in a large university hospital were processed for the 2012 fiscal year. For each of the 50 DRG groups with the most case-mix points, all diagnostic CT services were documented including their respective amount of GOÄ allocation credits and invoiced ICA value. As the German Institute for Reimbursement of Hospitals (InEK) database groups the radiation disciplines (radiology, nuclear medicine and radiation therapy) together and also lacks any modality differentiation, the determination of the diagnostic CT component was based on the existing institutional distribution of ICA allocations. Within the included 24,854 cases, 63,062,060 GOÄ-based performance credits were counted. The ICA relieved these diagnostic CT services by € 819,029 (single credit value of 1.30 Eurocent), whereas accounting by using DRG shares would have resulted in € 1,127,591 (single credit value of 1.79 Eurocent). The GOÄ single credit value is 5.62 Eurocent. The diagnostic CT service was basically rendered as relatively inexpensive. In addition to a better financial result, changing the current ICA to DRG shares might also mean a chance for real revenues. However, the attractiveness considerably depends on how the DRG shares are distributed to the different radiation disciplines of one institution.

Estimation of carbon allocation of Macauba palm (Acrocomia aculeata) - A new Brazilian biofuel alternative

NASA Astrophysics Data System (ADS)

Imbuzeiro, H. A.; Moreira, S. L. S.; Motoike, S. Y.; Fernandes, R. B. A.

2017-12-01

The Macauba palm (Acrocomia aculeata (Jacq.) Lood. ex Mart) is a native oil palm of the tropical America growing in anthropic areas, especially in grazing lands of Brazilian Cerrado. Macauba palm displays intense fruiting which results in high fruit and oil yield (3.0 - 6.0 ton/ha/year). The main Macauba palm differentials are: it is adapted to the environment with marked water restriction (1000 mm annual precipitation) which makes it resistant to drought and it does not compete with areas of rainforest; the oil is similar in composition to the African palm oil (Elaeis guineensis Jacq.) and can be used in several industrial applications such as biofuels, food, cosmetics, pharmaceutics and oil chemistry. Additionally, Macauba fruit processing generates several by-products like edible pulp bran, high-protein edible kernel bran, dense endocarp biomass, and husk biomass, all valuable products. Today, 172 million hectares of Brazilian land are used for grazing, of which 30 million hectares of these lands are degraded due to poor land use, 6 million in the state of Minas Gerais, in Brazil. Macauba could be cultivated in these degraded lands and is a candidate to become the main raw material for production of biokerosene. A new productive chain is forming in Brazil, the first commercial plantation of Macauba was implemented last year in Minas Gerais state and it is important to estimate the environmental impacts of this plantation, in terms of carbon (C) allocation. There is a lack of experimental data on Macauba carbon allocation and this study aimed to estimate the carbon allocation (leaves, stems and roots) of Macauba palm. The results suggest that Macauba palm is important in contributing to the carbon allocation.

Light energy partitioning, photosynthetic efficiency and biomass allocation in invasive Prunus serotina and native Quercus petraea in relation to light environment, competition and allelopathy.

PubMed

Robakowski, Piotr; Bielinis, Ernest; Sendall, Kerrie

2018-05-01

This study addressed whether competition under different light environments was reflected by changes in leaf absorbed light energy partitioning, photosynthetic efficiency, relative growth rate and biomass allocation in invasive and native competitors. Additionally, a potential allelopathic effect of mulching with invasive Prunus serotina leaves on native Quercus petraea growth and photosynthesis was tested. The effect of light environment on leaf absorbed light energy partitioning and photosynthetic characteristics was more pronounced than the effects of interspecific competition and allelopathy. The quantum yield of PSII of invasive P. serotina increased in the presence of a competitor, indicating a higher plasticity in energy partitioning for the invasive over the native Q. petraea, giving it a competitive advantage. The most striking difference between the two study species was the higher crown-level net CO 2 assimilation rates (A crown ) of P. serotina compared with Q. petraea. At the juvenile life stage, higher relative growth rate and higher biomass allocation to foliage allowed P. serotina to absorb and use light energy for photosynthesis more efficiently than Q. petraea. Species-specific strategies of growth, biomass allocation, light energy partitioning and photosynthetic efficiency varied with the light environment and gave an advantage to the invader over its native competitor in competition for light. However, higher biomass allocation to roots in Q. petraea allows for greater belowground competition for water and nutrients as compared to P. serotina. This niche differentiation may compensate for the lower aboveground competitiveness of the native species and explain its ability to co-occur with the invasive competitor in natural forest settings.

Sample Complexity Bounds for Differentially Private Learning

PubMed Central

Chaudhuri, Kamalika; Hsu, Daniel

2013-01-01

This work studies the problem of privacy-preserving classification – namely, learning a classifier from sensitive data while preserving the privacy of individuals in the training set. In particular, the learning algorithm is required in this problem to guarantee differential privacy, a very strong notion of privacy that has gained significant attention in recent years. A natural question to ask is: what is the sample requirement of a learning algorithm that guarantees a certain level of privacy and accuracy? We address this question in the context of learning with infinite hypothesis classes when the data is drawn from a continuous distribution. We first show that even for very simple hypothesis classes, any algorithm that uses a finite number of examples and guarantees differential privacy must fail to return an accurate classifier for at least some unlabeled data distributions. This result is unlike the case with either finite hypothesis classes or discrete data domains, in which distribution-free private learning is possible, as previously shown by Kasiviswanathan et al. (2008). We then consider two approaches to differentially private learning that get around this lower bound. The first approach is to use prior knowledge about the unlabeled data distribution in the form of a reference distribution chosen independently of the sensitive data. Given such a reference , we provide an upper bound on the sample requirement that depends (among other things) on a measure of closeness between and the unlabeled data distribution. Our upper bound applies to the non-realizable as well as the realizable case. The second approach is to relax the privacy requirement, by requiring only label-privacy – namely, that the only labels (and not the unlabeled parts of the examples) be considered sensitive information. An upper bound on the sample requirement of learning with label privacy was shown by Chaudhuri et al. (2006); in this work, we show a lower bound. PMID:25285183

The Neurobiology of Sexual Partner Preferences in Rams

PubMed Central

Roselli, Charles E.; Stormshak, Fred

2009-01-01

The question of what causes a male animal to seek out and choose a female as opposed to another male mating partner is unresolved and remains an issue of considerable debate. The most developed biologic theory is the perinatal organizational hypothesis, which states that perinatal hormone exposure mediates sexual differentiation of the brain. Numerous animal experiments have assessed the contribution of perinatal testosterone and/or estradiol exposure to the development of a male-typical mate preference, but almost all have used hormonally manipulated animals. In contrast, variations in sexual partner preferences occur spontaneously in domestic rams, with as many as 8% of the population exhibiting a preference for same-sex mating partners (male-oriented rams). Thus, the domestic ram is an excellent experimental model to study possible links between fetal neuroendocrine programming of neural mechanisms and adult sexual partner preferences. In this review, we present an overview of sexual differentiation in relation to sexual partner preferences. We then summarize results that test the relevance of the organizational hypothesis to expression of same-sex sexual partner preferences in rams. Finally, we demonstrate that the sexual differentiation of brain and behavior in sheep do not depend critically on aromatization of testosterone to estradiol. PMID:19446078

The neurobiology of sexual partner preferences in rams.

PubMed

Roselli, Charles E; Stormshak, Fred

2009-05-01

The question of what causes a male animal to seek out and choose a female as opposed to another male mating partner is unresolved and remains an issue of considerable debate. The most developed biologic theory is the perinatal organizational hypothesis, which states that perinatal hormone exposure mediates sexual differentiation of the brain. Numerous animal experiments have assessed the contribution of perinatal testosterone and/or estradiol exposure to the development of a male-typical mate preference, but almost all have used hormonally manipulated animals. In contrast, variations in sexual partner preferences occur spontaneously in domestic rams, with as many as 8% of the population exhibiting a preference for same-sex mating partners (male-oriented rams). Thus, the domestic ram is an excellent experimental model to study possible links between fetal neuroendocrine programming of neural mechanisms and adult sexual partner preferences. In this review, we present an overview of sexual differentiation in relation to sexual partner preferences. We then summarize results that test the relevance of the organizational hypothesis to expression of same-sex sexual partner preferences in rams. Finally, we demonstrate that the sexual differentiation of brain and behavior in sheep does not depend critically on aromatization of testosterone to estradiol.

Population genetic structure of gray wolves (Canis lupus) in a marine archipelago suggests island-mainland differentiation consistent with dietary niche.

PubMed

Stronen, Astrid V; Navid, Erin L; Quinn, Michael S; Paquet, Paul C; Bryan, Heather M; Darimont, Christopher T

2014-06-10

Emerging evidence suggests that ecological heterogeneity across space can influence the genetic structure of populations, including that of long-distance dispersers such as large carnivores. On the central coast of British Columbia, Canada, wolf (Canis lupus L., 1758) dietary niche and parasite prevalence data indicate strong ecological divergence between marine-oriented wolves inhabiting islands and individuals on the coastal mainland that interact primarily with terrestrial prey. Local holders of traditional ecological knowledge, who distinguish between mainland and island wolf forms, also informed our hypothesis that genetic differentiation might occur between wolves from these adjacent environments. We used microsatellite genetic markers to examine data obtained from wolf faecal samples. Our results from 116 individuals suggest the presence of a genetic cline between mainland and island wolves. This pattern occurs despite field observations that individuals easily traverse the 30 km wide study area and swim up to 13 km among landmasses in the region. Natal habitat-biased dispersal (i.e., the preference for dispersal into familiar ecological environments) might contribute to genetic differentiation. Accordingly, this working hypothesis presents an exciting avenue for future research where marine resources or other components of ecological heterogeneity are present.

Risk-Based, Hypothesis-Driven Framework for Hydrological Field Campaigns with Case Studies

NASA Astrophysics Data System (ADS)

Harken, B.; Rubin, Y.

2014-12-01

There are several stages in any hydrological modeling campaign, including: formulation and analysis of a priori information, data acquisition through field campaigns, inverse modeling, and prediction of some environmental performance metric (EPM). The EPM being predicted could be, for example, contaminant concentration or plume travel time. These predictions often have significant bearing on a decision that must be made. Examples include: how to allocate limited remediation resources between contaminated groundwater sites or where to place a waste repository site. Answering such questions depends on predictions of EPMs using forward models as well as levels of uncertainty related to these predictions. Uncertainty in EPM predictions stems from uncertainty in model parameters, which can be reduced by measurements taken in field campaigns. The costly nature of field measurements motivates a rational basis for determining a measurement strategy that is optimal with respect to the uncertainty in the EPM prediction. The tool of hypothesis testing allows this uncertainty to be quantified by computing the significance of the test resulting from a proposed field campaign. The significance of the test gives a rational basis for determining the optimality of a proposed field campaign. This hypothesis testing framework is demonstrated and discussed using various synthetic case studies. This study involves contaminated aquifers where a decision must be made based on prediction of when a contaminant will arrive at a specified location. The EPM, in this case contaminant travel time, is cast into the hypothesis testing framework. The null hypothesis states that the contaminant plume will arrive at the specified location before a critical amount of time passes, and the alternative hypothesis states that the plume will arrive after the critical time passes. The optimality of different field campaigns is assessed by computing the significance of the test resulting from each one. Evaluating the level of significance caused by a field campaign involves steps including likelihood-based inverse modeling and semi-analytical conditional particle tracking.

Task Demands in OSCEs Influence Learning Strategies.

PubMed

Lafleur, Alexandre; Laflamme, Jonathan; Leppink, Jimmie; Côté, Luc

2017-01-01

Models on pre-assessment learning effects confirmed that task demands stand out among the factors assessors can modify in an assessment to influence learning. However, little is known about which tasks in objective structured clinical examinations (OSCEs) improve students' cognitive and metacognitive processes. Research is needed to support OSCE designs that benefit students' metacognitive strategies when they are studying, reinforcing a hypothesis-driven approach. With that intent, hypothesis-driven physical examination (HDPE) assessments ask students to elicit and interpret findings of the physical exam to reach a diagnosis ("Examine this patient with a painful shoulder to reach a diagnosis"). When studying for HDPE, students will dedicate more time to hypothesis-driven discussions and practice than when studying for a part-task OSCE ("Perform the shoulder exam"). It is expected that the whole-task nature of HDPE will lead to a hypothesis-oriented use of the learning resources, a frequent use of adjustment strategies, and persistence with learning. In a mixed-methods study, 40 medical students were randomly paired and filmed while studying together for two hypothetical OSCE stations. Each 25-min study period began with video cues asking to study for either a part-task OSCE or an HDPE. In a crossover design, sequences were randomized for OSCEs and contents (shoulder or spine). Time-on-task for discussions or practice were categorized as "hypothesis-driven" or "sequence of signs and maneuvers." Content analysis of focus group interviews summarized students' perception of learning resources, adjustment strategies, and persistence with learning. When studying for HDPE, students allocate significantly more time for hypothesis-driven discussions and practice. Students use resources contrasting diagnoses and report persistence with learning. When studying for part-task OSCEs, time-on-task is reversed, spent on rehearsing a sequence of signs and maneuvers. OSCEs with similar contents but different task demands lead to opposite learning strategies regarding how students manage their study time. Measuring pre-assessment effects from a metacognitive perspective provides empirical evidence to redesign assessments for learning.

Heteroresistance at the single-cell level: adapting to antibiotic stress through a population-based strategy and growth-controlled interphenotypic coordination.

PubMed

Wang, Xiaorong; Kang, Yu; Luo, Chunxiong; Zhao, Tong; Liu, Lin; Jiang, Xiangdan; Fu, Rongrong; An, Shuchang; Chen, Jichao; Jiang, Ning; Ren, Lufeng; Wang, Qi; Baillie, J Kenneth; Gao, Zhancheng; Yu, Jun

2014-02-11

Heteroresistance refers to phenotypic heterogeneity of microbial clonal populations under antibiotic stress, and it has been thought to be an allocation of a subset of "resistant" cells for surviving in higher concentrations of antibiotic. The assumption fits the so-called bet-hedging strategy, where a bacterial population "hedges" its "bet" on different phenotypes to be selected by unpredicted environment stresses. To test this hypothesis, we constructed a heteroresistance model by introducing a blaCTX-M-14 gene (coding for a cephalosporin hydrolase) into a sensitive Escherichia coli strain. We confirmed heteroresistance in this clone and that a subset of the cells expressed more hydrolase and formed more colonies in the presence of ceftriaxone (exhibited stronger "resistance"). However, subsequent single-cell-level investigation by using a microfluidic device showed that a subset of cells with a distinguishable phenotype of slowed growth and intensified hydrolase expression emerged, and they were not positively selected but increased their proportion in the population with ascending antibiotic concentrations. Therefore, heteroresistance--the gradually decreased colony-forming capability in the presence of antibiotic--was a result of a decreased growth rate rather than of selection for resistant cells. Using a mock strain without the resistance gene, we further demonstrated the existence of two nested growth-centric feedback loops that control the expression of the hydrolase and maximize population growth in various antibiotic concentrations. In conclusion, phenotypic heterogeneity is a population-based strategy beneficial for bacterial survival and propagation through task allocation and interphenotypic collaboration, and the growth rate provides a critical control for the expression of stress-related genes and an essential mechanism in responding to environmental stresses. Heteroresistance is essentially phenotypic heterogeneity, where a population-based strategy is thought to be at work, being assumed to be variable cell-to-cell resistance to be selected under antibiotic stress. Exact mechanisms of heteroresistance and its roles in adaptation to antibiotic stress have yet to be fully understood at the molecular and single-cell levels. In our study, we have not been able to detect any apparent subset of "resistant" cells selected by antibiotics; on the contrary, cell populations differentiate into phenotypic subsets with variable growth statuses and hydrolase expression. The growth rate appears to be sensitive to stress intensity and plays a key role in controlling hydrolase expression at both the bulk population and single-cell levels. We have shown here, for the first time, that phenotypic heterogeneity can be beneficial to a growing bacterial population through task allocation and interphenotypic collaboration other than partitioning cells into different categories of selective advantage.

Vector- and tensor-meson production and the Pomeron-f identity hypothesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, S.T.

Within the context of a model introduced some time ago, the differential and total production cross sections for vector and tensor mesons are shown to be compatible with the hypothesis that the Pomeron and f are a single Regge trajectory. The model incorporates both cylinder and flavoring renormalizations of the Pomeron-f trajectory. The processes K/sup +- /p..-->..K/sup */(892)/sup +- /p, K/sup +- /p ..-->..K/sub 2//sup */(1430)/sup +- /p, and ..pi../sup +- /p..-->..A/sub 2/(1320)/sup +- /p are analyzed in some detail.

Using CRANID to test the population affinity of known crania.

PubMed

Kallenberger, Lauren; Pilbrow, Varsha

2012-11-01

CRANID is a statistical program used to infer the source population of a cranium of unknown origin by comparing its cranial dimensions with a worldwide craniometric database. It has great potential for estimating ancestry in archaeological, forensic and repatriation cases. In this paper we test the validity of CRANID in classifying crania of known geographic origin. Twenty-three crania of known geographic origin but unknown sex were selected from the osteological collections of the University of Melbourne. Only 18 crania showed good statistical match with the CRANID database. Without considering accuracy of sex allocation, 11 crania were accurately classified into major geographic regions and nine were correctly classified to geographically closest available reference populations. Four of the five crania with poor statistical match were nonetheless correctly allocated to major geographical regions, although none was accurately assigned to geographically closest reference samples. We conclude that if sex allocations are overlooked, CRANID can accurately assign 39% of specimens to geographically closest matching reference samples and 48% to major geographic regions. Better source population representation may improve goodness of fit, but known sex-differentiated samples are needed to further test the utility of CRANID. © 2012 The Authors Journal of Anatomy © 2012 Anatomical Society.

Importance of breeding season and maternal investment in studies of sex-ratio adjustment: a case study using tree swallows

PubMed Central

Baeta, Renaud; Bélisle, Marc; Garant, Dany

2012-01-01

The control of primary sex-ratio by vertebrates has become a major focus in biology in recent years. Evolutionary theory predicts that a differential effect of maternal characteristics on the fitness of sons and daughters is an important route, whereby selection is expected to favour a bias towards the production of one sex. However, despite experimental evidence for adaptive brood sex-ratio manipulation, support for this prediction remains a major challenge in vertebrates where inconsistencies between correlative studies are frequently reported. Here, we used a large dataset (2215 nestlings over 3 years) from a wild population of tree swallows (Tachycineta bicolor) and show that variations in breeding conditions affect female sex allocation in this species. Our results also suggest that such variation in sex allocation, owing to breeding season heterogeneity, modifies the relationships between maternal characteristics and maternal investment. Indeed, we detect a positive effect of maternal age on brood sex-ratio when age also affects offspring condition (in a low-quality breeding season). Our results indicate that including measures of both breeding season quality and maternal investment will help to better understand sex allocation patterns. PMID:22130173

On asymptotic behavior and energy distribution for some one-dimensional non-parabolic diffusion problems

NASA Astrophysics Data System (ADS)

Kim, Seonghak; Yan, Baisheng

2018-06-01

We study some non-parabolic diffusion problems in one space dimension, where the diffusion flux exhibits forward and backward nature of the Perona–Malik, Höllig or non-Fourier type. Classical weak solutions to such problems are constructed in a way to capture some expected and unexpected properties, including anomalous asymptotic behaviors and energy dissipation or allocation. Specific properties of solutions will depend on the type of the diffusion flux, but the primary method of our study relies on reformulating diffusion equations involved as an inhomogeneous partial differential inclusion and on constructing solutions from the differential inclusion by a combination of the convex integration and Baire’s category methods. In doing so, we introduce the appropriate notion of subsolutions of the partial differential inclusion and their transition gauge, which plays a pivotal role in dealing with some specific features of the constructed weak solutions.

Social status and the pursuit of positive social identity: Systematic domains of intergroup differentiation and discrimination for high- and low- status groups

PubMed Central

Oldmeadow, Julian A.; Fiske, Susan T.

2013-01-01

Research on intergroup discrimination has focused on the cognitive and motivational mechanisms involved, but the role of stereotype content has been neglected. Drawing on social identity theory and stereotype content research, the current studies investigated the role of stereotype content in intergroup differentiation and discrimination. Across two studies, students from high- and low-status groups differentiated themselves positively on stereotypes of competence and warmth respectively, and in allocations of resources in domains relevant to competence (academics, research) and warmth (sports, community outreach). Furthermore, there was evidence that discrimination by high- and low-status groups was driven by their respective stereotypes of competence and warmth. It is argued that stereotypes of competence and warmth, derived from status and power relations between groups, define the domains in which groups pursue positively distinct identities. PMID:24319344

The lifespan-reproduction trade-off under dietary restriction is sex-specific and context-dependent.

PubMed

Adler, Margo I; Cassidy, Elizabeth J; Fricke, Claudia; Bonduriansky, Russell

2013-06-01

Adult dietary restriction (DR) extends lifespan, but the mechanisms that underlie this effect are not well understood. Many DR studies have demonstrated that lifespan extension tends to be accompanied by a reduction in female fecundity - a correlation widely interpreted as evidence that DR triggers an adaptive re - allocation of resources from reproduction to somatic maintenance. Yet, recent evidence suggests that survival and fecundity need not always trade off under DR, calling the re-allocation hypothesis into question. Because the effects of DR on both survival and reproduction have rarely been tested in both sexes, or under a range of ecologically-relevant environments, the generality of this trade-off remains unclear. We examined the effects of DR on survival and reproduction in both sexes and across a range of environments (larval diet quality and adult sex ratio) in the neriid fly Telostylinus angusticollis. We found that the lifespan-reproduction trade-off is both context- and sex-dependent. Although DR extended lifespan in both sexes by 65% and rendered females completely infertile, costs of DR on male fecundity were subtle and evident only in particular environmental combinations. Our findings suggest that a re-allocation of resources may not underlie the lifespan extension response to DR. Instead, full feeding may be associated with increased costs in comparison to DR, such that lifespan extension may be achieved without an increased resource investment to the soma. Copyright © 2013 Elsevier Inc. All rights reserved.

Role of Sectoral Transformation in the Evolution of Water Management Norms in Agricultural Catchments: A Sociohydrologic Modeling Analysis

NASA Astrophysics Data System (ADS)

Roobavannan, M.; Kandasamy, J.; Pande, S.; Vigneswaran, S.; Sivapalan, M.

2017-10-01

This study is focused on the water-agriculture-environment nexus as it played out in the Murrumbidgee River Basin, eastern Australia, and how coevolution of society and water management actually transpired. Over 100 years of agricultural development the Murrumbidgee Basin experienced a "pendulum swing" in terms of water allocation, initially exclusively for agriculture production changing over to reallocation back to the environment. In this paper, we hypothesize that in the competition for water between economic livelihood and environmental wellbeing, economic diversification was the key to swinging community sentiment in favor of environmental protection, and triggering policy action that resulted in more water allocation to the environment. To test this hypothesis, we developed a sociohydrology model to link the dynamics of the whole economy (both agriculture and industry composed of manufacturing and services) to the community's sensitivity toward the environment. Changing community sensitivity influenced how water was allocated and governed and how the agricultural sector grew relative to the industrial sector (composed of manufacturing and services sectors). In this way, we show that economic diversification played a key role in influencing the community's values and preferences with respect to the environment and economic growth. Without diversification, model simulations show that the community would not have been sufficiently sensitive and willing enough to act to restore the environment, highlighting the key role of sectoral transformation in achieving the goal of sustainable agricultural development.

Age Differentiation within Gray Matter, White Matter, and between Memory and White Matter in an Adult Life Span Cohort.

PubMed

de Mooij, Susanne M M; Henson, Richard N A; Waldorp, Lourens J; Kievit, Rogier A

2018-06-20

It is well established that brain structures and cognitive functions change across the life span. A long-standing hypothesis called "age differentiation" additionally posits that the relations between cognitive functions also change with age. To date, however, evidence for age-related differentiation is mixed, and no study has examined differentiation of the relationship between brain and cognition. Here we use multigroup structural equation models (SEMs) and SEM trees to study differences within and between brain and cognition across the adult life span (18-88 years) in a large ( N > 646, closely matched across sexes), population-derived sample of healthy human adults from the Cambridge Centre for Ageing and Neuroscience (www.cam-can.org). After factor analyses of gray matter volume (from T1- and T2-weighted MRI) and white matter organization (fractional anisotropy from diffusion-weighted MRI), we found evidence for the differentiation of gray and white matter, such that the covariance between brain factors decreased with age. However, we found no evidence for age differentiation among fluid intelligence, language, and memory, suggesting a relatively stable covariance pattern among cognitive factors. Finally, we observed a specific pattern of age differentiation between brain and cognitive factors, such that a white matter factor, which loaded most strongly on the hippocampal cingulum, became less correlated with memory performance in later life. These patterns are compatible with the reorganization of cognitive functions in the face of neural decline, and/or with the emergence of specific subpopulations in old age. SIGNIFICANCE STATEMENT The theory of age differentiation posits age-related changes in the relationships among cognitive domains, either weakening (differentiation) or strengthening (dedifferentiation), but evidence for this hypothesis is mixed. Using age-varying covariance models in a large cross-sectional adult life span sample, we found age-related reductions in the covariance among both brain measures (neural differentiation), but no covariance change among cognitive factors of fluid intelligence, language, and memory. We also observed evidence of uncoupling (differentiation) between a white matter factor and cognitive factors in older age, most strongly for memory. Together, our findings support age-related differentiation as a complex, multifaceted pattern that differs for brain and cognition, and discuss several mechanisms that might explain the changing relationship between brain and cognition. Copyright © 2018 de Mooij et al.

Parental preferences and allocations of investments in children's learning and health within families.

PubMed

Abufhele, Alejandra; Behrman, Jere; Bravo, David

2017-12-01

Empirical evidence suggests that parental preferences may be important in determining investment allocations among their children. However, there is mixed or no evidence on a number of important related questions. Do parents invest more in better-endowed children, thus reinforcing differentials among their children? Or do they invest more in less-endowed children to compensate for their smaller endowments and reduce inequalities among their children? Does higher maternal education affect the preferences underlying parental decisions in investing among their children? What difference might such intrafamilial investments among children make? And what is the nature of these considerations in the very different context of developing countries? This paper gives new empirical evidence related to these questions. We examine how parental investments affecting child education and health respond to initial endowment differences between twins within families, as represented by birth weight differences, and how parental preference tradeoffs and therefore parental investment strategies vary between families with different maternal education. Using the separable earnings-transfers model (Behrman et al., 1982), we first illustrate that preference differences may make a considerable difference in the ratios of health and learning differentials between siblings - up to 30% in the simulations that we provide. Using a sample of 2000 twins, collected in the 2012 wave of the Early Childhood Longitudinal Survey for Chile, we find that preferences are not at the extreme of pure compensatory investments to offset endowment inequalities among siblings nor at the extreme of pure reinforcement to favor the better-endowed child with no concern about inequality. Instead, they are neutral, so that parental investments do not change the inequality among children due to endowment differentials. We also find that there are not significant preference differences between families with low- and high-educated mothers. Our estimates are consistent with previous empirical evidence that finds that parents do not invest differentially within twins. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ambiguity produces attention shifts in category learning.

PubMed

Vadillo, Miguel A; Orgaz, Cristina; Luque, David; Nelson, James Byron

2016-04-01

It has been suggested that people and nonhuman animals protect their knowledge from interference by shifting attention toward the context when presented with information that contradicts their previous beliefs. Despite that suggestion, no studies have directly measured changes in attention while participants are exposed to an interference treatment. In the present experiments, we adapted a dot-probe task to track participants' attention to cues and contexts while they were completing a simple category learning task. The results support the hypothesis that interference produces a change in the allocation of attention to cues and contexts. © 2016 Vadillo et al.; Published by Cold Spring Harbor Laboratory Press.

Carborundum, a bulk similar to dietary fibers but chemically inert, does not decrease colon carcinogenesis.

PubMed

Corpet, D E; Taché, S; Peiffer, G

1997-03-19

Dietary fibers might lower the risk of colorectal cancer, maybe because of their bulking effect. We tested the protection afforded by an inert bulk against carcinogenesis. Thirty rats received an azoxymethane injection and were allocated to a control diet, or to a diet supplemented with 10% carborundum. After 100 days the colons were scored for aberrant crypt foci. Compared to controls, the fecal weight was doubled in carborundum-fed rats (P < 0.001), but the aberrant crypt foci multiplicity was not changed (P = 0.92). The results do not support the hypothesis that intestinal dilution by an inert bulk can protect against colon cancer.

Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

NASA Astrophysics Data System (ADS)

Hoey, J.; McCormick, M. I.; Hoey, A. S.

2007-09-01

The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5-39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output.

The business of radiology: cost accounting.

PubMed

Camponovo, Ernest J

2004-08-01

Radiology practices confront questions of resource allocation every day. Unfortunately, practices frequently fail to adequately analyze revenues and expenses, which are at the heart of success or failure in any business endeavor. Cost allocation problems permeate nearly all aspects of cost analysis and accumulation and exist throughout all types of private-sector and public-sector organizations. "Managerial" or "cost" accounting is the discipline concerned with measuring and assigning the costs of delivering services or producing products. In contrast to financial accounting, management accounting produces relevant information for internal decision making and in general is designed to answer a firm's specific operational questions. Because costs play such a critical role in deriving and planning for revenues and profits, managerial accounting is in large part devoted to measuring and accumulating costs with the aims of control and continuous cost reduction. Because radiologists' salaries are at record highs, when accounting for a practice's clinical activities, such as the provision of mammography services, some allocation of radiologist costs themselves must be made, or the practice will not be able to achieve its goal of efficient allocation of resources. Whatever cost-accounting method is used should be specific enough to allow the differentiation of costs to as detailed a level as necessary for the strategic decision at hand. It is imperative that a practice use some rational method to gather and analyze costs and that management then use these data in decision making. Successful practices will be those most aware of their costs and the minimum acceptable reimbursements necessary for their success.

Psychosocial risk factors which may differentiate between women with Functional Voice Disorder, Organic Voice Disorder and a Control group.

PubMed

Baker, Janet; Ben-Tovim, David; Butcher, Andrew; Esterman, Adrian; McLaughlin, Kristin

2013-12-01

This study aimed to explore psychosocial factors contributing to the development of functional voice disorders (FVD) and those differentiating between organic voice disorders (OVD) and a non-voice-disordered control group. A case-control study was undertaken of 194 women aged 18-80 years diagnosed with FVD (n = 73), OVD (n = 55), and controls (n = 66). FVD women were allocated into psychogenic voice disorder (PVD) (n = 37) and muscle tension voice disorder (MTVD) (n = 36) for sub-group analysis. Dependent variables included biographical and voice assessment data, the number and severity of life events and difficulties and conflict over speaking out (COSO) situations derived from the Life Events and Difficulties Schedule (LEDS), and psychological traits including emotional expressiveness scales. Four psychosocial components differentiated between the FVD and control group accounting for 84.9% of the variance: severe events, moderate events, severe COSO, and mild COSO difficulties. Severe events, severe and mild COSO difficulties differentiated between FVD and OVD groups, accounting for 80.5% of the variance. Moderate events differentiated between PVD and MTVD sub-groups, accounting for 58.9% of the variance. Psychological traits did not differentiate between groups. Stressful life events and COSO situations best differentiated FVD from OVD and control groups. More refined aetiological studies are needed to differentiate between PVD and MTVD.

The Use of Microgravity To Emulate Three-Dimensional Tissue Interactions in Colorectal Cancer Metastasis

NASA Technical Reports Server (NTRS)

Jessup, J. Milburn

1997-01-01

The hypothesis of this ground-based project was that simulated microgravity may be used to recreate with high fidelity the in vivo environment in tissue culture. The objectives were to determine whether: (1) simulated microgravity induces differentiation within poorly differentiated human colon carcinoma cells that are similar to that observed in experimental metastases in vivo in nude mice; and (2) the use of simulated microgravity helps define the experimental metastatic potential of human colorectal carcinoma.

Emergent Leadership and Team Effectiveness on a Team Resource Allocation Task

DTIC Science & Technology

1987-10-01

equivalent training and experience on this task, but they had different levels of experience with computers and video games . This differential experience...typed: that is. it is sex-typed to the extent that males spend mnore time on related instrumeuts like computers and video games . However. the sex...perform better or worse than less talkative teams? Did teams with much computer and ’or video game experience perform better than inexperienced teams

American Mathematics from 1940 to the Day Before Yesterday

ERIC Educational Resources Information Center

Ewing, J. H.; And Others

1976-01-01

Ten recent results in pure mathematics are described, covering the continuum hypothesis, Diophantine equations, simple groups, resolution of singularities, Weil conjectures, Lie groups, Poincare conjecture, exotic spheres, differential equations, and the index theorem. Proofs are omitted, but references are provided. (DT)

NASA's Discovery Mission to (16) Psyche: Visiting a Metal World

NASA Astrophysics Data System (ADS)

Elkins-Tanton, L. T.; Bell, J. F., III

2017-09-01

The Psyche mission is one of NASA's most recent Discovery mission selections. It is designed to explore the large metallic Main Belt asteroid (16) Psyche and test the hypothesis that it is the exposed core of an ancient differentiated planetesimal.

Understanding Senile Dementia: A Challenge for the Future.

ERIC Educational Resources Information Center

Storandt, Martha

1983-01-01

Reviews causes of dementia in later life, especially the Alzheimer's type, its prevalence, the characteristic structural changes, and hypothesized causes. The hypothesis that Alzheimer's disease represents accelerated aging is described. Treatment issues are discussed, primarily in terms of supportive environments, differential diagnosis, and…

Explanation and Categorization: How "Why?" Informs "What?"

ERIC Educational Resources Information Center

Lombrozo, Tania

2009-01-01

Recent theoretical and empirical work suggests that explanation and categorization are intimately related. This paper explores the hypothesis that explanations can help structure conceptual representations, and thereby influence the relative importance of features in categorization decisions. In particular, features may be differentially important…

Patient-Therapist Identification in Relation to Both Patient and Therapist Variables and Therapy Outcome

ERIC Educational Resources Information Center

Melnick, Barry

1972-01-01

The results of the study confirmed the hypothesis that greater patient identification with the therapist, as defined by increased similarity between the patient's and therapist's semantic differential ratings, moderately correlated with more successful therapy outcome. (Author)

Munchausen by proxy: the dark side of parental investment theory?

PubMed

Saad, Gad

2010-12-01

The parental investment hypothesis provides a parsimonious explanation for a wide range of sexually dimorphic traits and behaviors across countless species. In the human context, the hypothesis posits that in light of the differentially greater parental investment that human females provide to their offspring, they should be much more vested in the wellbeing of their children. Munchausen Syndrome by Proxy (MSbP) occurs when a caregiver feigns or causes a medical condition in a dependent (typically a child). In the great majority of cases, the biological mother is the perpetrator, which is thus deeply surprising from an evolutionary perspective. I propose that for a small sample of women (e.g., those suffering from specific personality disorders and who do not possess the necessary support from their husbands/partners), the parental investment hypothesis is usurped or subverted in the service of their narcissistic need for attention (especially from high-status male physicians). Hence, in the same way that infanticide can be explained from a Darwinian perspective (despite it being at first glance incongruent with kin selection theory), MSbP appears to be equally amenable to an evolutionary analysis. One can test the hypothesis by demonstrating that the sex-specificity of the disorder holds true irrespective of cultural setting and epoch. Furthermore, one can look at single-parental families (as a means of controlling for the otherwise differential access to children in dual-parent homes) to show that within this controlled environment, mothers will remain the greater perpetrators of MSbP. Copyright © 2010 Elsevier Ltd. All rights reserved.

Learning to multitask: effects of video game practice on electrophysiological indices of attention and resource allocation.

PubMed

Maclin, Edward L; Mathewson, Kyle E; Low, Kathy A; Boot, Walter R; Kramer, Arthur F; Fabiani, Monica; Gratton, Gabriele

2011-09-01

Changes in attention allocation with complex task learning reflect processing automatization and more efficient control. We studied these changes using ERP and EEG spectral analyses in subjects playing Space Fortress, a complex video game comprising standard cognitive task components. We hypothesized that training would free up attentional resources for a secondary auditory oddball task. Both P3 and delta EEG showed a processing trade-off between game and oddball tasks, but only some game events showed reduced attention requirements with practice. Training magnified a transient increase in alpha power following both primary and secondary task events. This contrasted with alpha suppression observed when the oddball task was performed alone, suggesting that alpha may be related to attention switching. Hence, P3 and EEG spectral data are differentially sensitive to changes in attentional processing occurring with complex task training. Copyright © 2011 Society for Psychophysiological Research.

Pricing Resources in LTE Networks through Multiobjective Optimization

PubMed Central

Lai, Yung-Liang; Jiang, Jehn-Ruey

2014-01-01

The LTE technology offers versatile mobile services that use different numbers of resources. This enables operators to provide subscribers or users with differential quality of service (QoS) to boost their satisfaction. On one hand, LTE operators need to price the resources high for maximizing their profits. On the other hand, pricing also needs to consider user satisfaction with allocated resources and prices to avoid “user churn,” which means subscribers will unsubscribe services due to dissatisfaction with allocated resources or prices. In this paper, we study the pricing resources with profits and satisfaction optimization (PRPSO) problem in the LTE networks, considering the operator profit and subscribers' satisfaction at the same time. The problem is modelled as nonlinear multiobjective optimization with two optimal objectives: (1) maximizing operator profit and (2) maximizing user satisfaction. We propose to solve the problem based on the framework of the NSGA-II. Simulations are conducted for evaluating the proposed solution. PMID:24526889

Pricing resources in LTE networks through multiobjective optimization.

PubMed

Lai, Yung-Liang; Jiang, Jehn-Ruey

2014-01-01

The LTE technology offers versatile mobile services that use different numbers of resources. This enables operators to provide subscribers or users with differential quality of service (QoS) to boost their satisfaction. On one hand, LTE operators need to price the resources high for maximizing their profits. On the other hand, pricing also needs to consider user satisfaction with allocated resources and prices to avoid "user churn," which means subscribers will unsubscribe services due to dissatisfaction with allocated resources or prices. In this paper, we study the pricing resources with profits and satisfaction optimization (PRPSO) problem in the LTE networks, considering the operator profit and subscribers' satisfaction at the same time. The problem is modelled as nonlinear multiobjective optimization with two optimal objectives: (1) maximizing operator profit and (2) maximizing user satisfaction. We propose to solve the problem based on the framework of the NSGA-II. Simulations are conducted for evaluating the proposed solution.

General child benefit fund experiments in providing differentiated services.

PubMed

Serres, Anne-Marie

2005-10-01

Populations not autonomous in their administrative relations has difficulties with access to social benefits of the Caisses d'Allocations Familiales (CAFs). These difficulties, whether rooted in cultural, educational, social, or other issues, disrupt the management of their documents of social benefits and thereby weigh on their economic situations. From 1998 to 2000, five CAFs tested suitable solutions to situations of beneficiaries for whom standardized procedures have shown their limits, in the areas of housing, compensatory allocations of revenues, and given territories. They have defined goals, methods, and indicators for complex situations and have regular assessments of the management of the project as the project is going on. These results concern a better understanding of the beneficiaries, understanding of the services to provide them with, and the benefits for the beneficiaries, for the agents, for the CAF, and for its relations with the partners associated with their missions.

Customer and service profitability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballaban, M.; Kelly, K.; Wisniewski, L.

1996-03-01

The rapid pace of competitive change in the generation sector has pushed electric utilities to rethink the concept of being obligated to serve all customers and with this change, the notion of measuring customer profitability is also being redefined. Traditionally, uniform services were provided to all customers. Rates were based on each customer classes` contribution to average costs, and consequently return was equally allocated across all customer segments. Profitability was defined strictly on an aggregate basis. The increasing demand for choice by electric customers will require electricity providers to redefine if not who they serve, than certainly how they providemore » differentiated services tailored to specific customer segments. Utilities are beginning to analyze the value, or profitability, of offering these services. Aggregate data no longer provides an accurate assessment of how resources should be allocated most efficiently. As services are unbundled, so too must costs be disaggregated to effectively measure the profitability of various options.« less

An analysis of choice making in the assessment of young children with severe behavior problems.

PubMed

Harding, J W; Wacker, D P; Berg, W K; Cooper, L J; Asmus, J; Mlela, K; Muller, J

1999-01-01

We examined how positive and negative reinforcement influenced time allocation, occurrence of problem behavior, and completion of parent instructions during a concurrent choice assessment with 2 preschool-aged children who displayed severe problem behavior in their homes. The children were given a series of concurrent choice options that varied availability of parent attention, access to preferred toys, and presentation of parent instructions. The results showed that both children consistently allocated their time to choice areas that included parent attention when no instructions were presented. When parent attention choice areas included the presentation of instructions, the children displayed differential patterns of behavior that appeared to be influenced by the presence or absence of preferred toys. The results extended previous applications of reinforcer assessment procedures by analyzing the relative influence of both positive and negative reinforcement within a concurrent-operants paradigm.

Utilization of health technologies-Do not look where there is a light; shine your light where there is a need to look! Relating national health goals with resource allocation decision-making; illustration through examining the Israeli healthcare system.

PubMed

Shavit, Oren

2009-10-01

Innovative health technologies are often the focus of attention. However, in the allocation of public resources for improving health, the focus should be on the health needs of the population. It is the need that should be analyzed first, and decision makers should then evaluate the full range of interventions available, whether new or old, to meet this need. This is in contrast to analyzing the technology first and then characterizing the need it meets, which is the current practice in reimbursement decision-making in several countries. The identified health need should define national health goals, and these goals should be proactively assimilated into the reimbursement decision-making process. Differential reimbursement rates could reflect the relative contribution of the technology to the unmet health need.

Balanced states of mind in psychopathology and psychological well-being.

PubMed

Wong, Shyh Shin

2010-08-01

The balanced states of mind (BSOM) model proposes that coping with stress and psychological well-being is a function of the BSOM ratio of positive thoughts to the sum of positive and negative thoughts. Based on different BSOM ratios, different BSOM categories are constructed to quantitatively differentiate levels of coping with stress and psychological well-being. The cognitive content-specificity hypothesis states that there are unique themes of semantic content in self-reported automatic thoughts particular to depression or anxiety. This study investigated the BSOM model and its cognitive content-specificity for depression, anxiety, anger, stress, life satisfaction, and happiness, based on negative and positive automatic thoughts. Three hundred and ninety-eight college students from Singapore participated in this study. First, BSOM ratio and positive automatic thoughts were positively correlated with life satisfaction and happiness, and negatively correlated with stress, anxiety, depression, and anger. In contrast, negative automatic thoughts were positively correlated with stress, anxiety, depression, and anger, and negatively correlated with life satisfaction and happiness. Second, levels of psychopathology and psychological well-being were statistically differentiable among the BSOM categories for depression, happiness, perceived stress, and life satisfaction; and less statistically differentiable among the BSOM categories for anxiety and anger, as expected based on the BSOM model and cognitive content-specificity hypothesis. Third, the results were more supportive of the BSOM model for depression, followed by happiness, perceived stress, life satisfaction, anxiety, and anger in terms of percentage of variance accounted for by BSOM categories, as expected based on the cognitive content-specificity hypothesis. Taken together, the results suggested that the more moderately positive thoughts one has (balanced by negative thoughts), the better mental health outcomes one has. Implications and limitations of these findings are discussed.

Highly local environmental variability promotes intrapopulation divergence of quantitative traits: an example from tropical rain forest trees.

PubMed

Brousseau, Louise; Bonal, Damien; Cigna, Jeremy; Scotti, Ivan

2013-10-01

In habitat mosaics, plant populations face environmental heterogeneity over short geographical distances. Such steep environmental gradients can induce ecological divergence. Lowland rainforests of the Guiana Shield are characterized by sharp, short-distance environmental variations related to topography and soil characteristics (from waterlogged bottomlands on hydromorphic soils to well-drained terra firme on ferralitic soils). Continuous plant populations distributed along such gradients are an interesting system to study intrapopulation divergence at highly local scales. This study tested (1) whether conspecific populations growing in different habitats diverge at functional traits, and (2) whether they diverge in the same way as congeneric species having different habitat preferences. Phenotypic differentiation was studied within continuous populations occupying different habitats for two congeneric, sympatric, and ecologically divergent tree species (Eperua falcata and E. grandiflora, Fabaceae). Over 3000 seeds collected from three habitats were germinated and grown in a common garden experiment, and 23 morphological, biomass, resource allocation and physiological traits were measured. In both species, seedling populations native of different habitats displayed phenotypic divergence for several traits (including seedling growth, biomass allocation, leaf chemistry, photosynthesis and carbon isotope composition). This may occur through heritable genetic variation or other maternally inherited effects. For a sub-set of traits, the intraspecific divergence associated with environmental variation coincided with interspecific divergence. The results indicate that mother trees from different habitats transmit divergent trait values to their progeny, and suggest that local environmental variation selects for different trait optima even at a very local spatial scale. Traits for which differentiation within species follows the same pattern as differentiation between species indicate that the same ecological processes underlie intra- and interspecific variation.

Highly local environmental variability promotes intrapopulation divergence of quantitative traits: an example from tropical rain forest trees

PubMed Central

Brousseau, Louise; Bonal, Damien; Cigna, Jeremy; Scotti, Ivan

2013-01-01

Background and Aims In habitat mosaics, plant populations face environmental heterogeneity over short geographical distances. Such steep environmental gradients can induce ecological divergence. Lowland rainforests of the Guiana Shield are characterized by sharp, short-distance environmental variations related to topography and soil characteristics (from waterlogged bottomlands on hydromorphic soils to well-drained terra firme on ferralitic soils). Continuous plant populations distributed along such gradients are an interesting system to study intrapopulation divergence at highly local scales. This study tested (1) whether conspecific populations growing in different habitats diverge at functional traits, and (2) whether they diverge in the same way as congeneric species having different habitat preferences. Methods Phenotypic differentiation was studied within continuous populations occupying different habitats for two congeneric, sympatric, and ecologically divergent tree species (Eperua falcata and E. grandiflora, Fabaceae). Over 3000 seeds collected from three habitats were germinated and grown in a common garden experiment, and 23 morphological, biomass, resource allocation and physiological traits were measured. Key Results In both species, seedling populations native of different habitats displayed phenotypic divergence for several traits (including seedling growth, biomass allocation, leaf chemistry, photosynthesis and carbon isotope composition). This may occur through heritable genetic variation or other maternally inherited effects. For a sub-set of traits, the intraspecific divergence associated with environmental variation coincided with interspecific divergence. Conclusions The results indicate that mother trees from different habitats transmit divergent trait values to their progeny, and suggest that local environmental variation selects for different trait optima even at a very local spatial scale. Traits for which differentiation within species follows the same pattern as differentiation between species indicate that the same ecological processes underlie intra- and interspecific variation. PMID:24023042

Ecotypic differentiation between urban and rural populations of the grasshopper Chorthippus brunneus relative to climate and habitat fragmentation.

PubMed

San Martin Y Gomez, Gilles; Van Dyck, Hans

2012-05-01

Urbanization alters environmental conditions in multiple ways and offers an ecological or evolutionary challenge for organisms to cope with. Urban areas typically have a warmer climate and strongly fragmented herbaceous vegetation; the urban landscape matrix is often assumed to be hostile for many organisms. Here, we addressed the issue of evolutionary differentiation between urban and rural populations of an ectotherm insect, the grasshopper Chorthippus brunneus. We compared mobility-related morphology and climate-related life history traits measured on the first generation offspring of grasshoppers from urban and rural populations reared in a common garden laboratory experiment. We predicted (1) the urban phenotype to be more mobile (i.e., lower mass allocation to the abdomen, longer relative femur and wing lengths) than the rural phenotype; (2) the urban phenotype to be more warm adapted (e.g., higher female body mass); and (3) further evidence of local adaptation in the form of significant interaction effects between landscape of origin and breeding temperature. Both males and females of urban origin had significantly longer relative femur and wing lengths and lower mass allocation to the abdomen (i.e., higher investment in thorax and flight muscles) relative to individuals of rural origin. The results were overall significant but small (2-4%). Body mass and larval growth rate were much higher (+10%) in females of urban origin. For the life history traits, we did not find evidence for significant interaction effects between the landscape of origin and the two breeding temperatures. Our results point to ecotypic differentiation with urbanization for mobility-related morphology and climate-related life history traits. We argue that the warmer urban environment has an indirect effect through longer growth season rather than direct effects on the development.

Testing the prenatal hormone hypothesis of tic-related disorders: gender identity and gender role behavior.

PubMed

Alexander, Gerianne M; Peterson, Bradley S

2004-01-01

The hypothesis that prenatal masculinization of the brain increases risk of tic disorders in postnatal life was tested by measuring gender and gender role behavior in 89 children and adults with a clinical diagnosis of Tourette syndrome or obsessive compulsive disorder and 67 healthy, unaffected children and adults. Consistent with this hypothesis, a tic disorder in females was associated with more gender dysphoria, increased masculine play preferences, and a more typically "masculine" pattern of performance on two sex-typed spatial tasks. Males with tic disorders reported increased masculine play preferences, and the strength of these preferences was positively associated with the severity of tic symptoms. In addition, unlike their female counterparts, males with tic disorders showed a relative impairment in mental rotation ability. These behavioral profiles are consistent with those of children who have verifiable elevations in prenatal androgen levels. These findings therefore support the hypothesis that an altered androgen-dependent process of sexual differentiation during prenatal life may contribute to the development of tic-related disorders.

Circulating microRNA as candidates for early embryonic viability in cattle

USDA-ARS?s Scientific Manuscript database

Blood borne extracellular vesicles (EVs; i.e. exosomes and microvesicles) carrying microRNA (miRNA) may make excellent biomarkers of disease conditions and different physiologic states, including pregnancy status. We tested the hypothesis that circulating EV-derived miRNA might differentiate pregnan...

Cumulative-Genetic Plasticity, Parenting and Adolescent Self-Regulation

ERIC Educational Resources Information Center

Belsky, Jay; Beaver, Kevin M.

2011-01-01

Background: The capacity to control or regulate one's emotions, cognitions and behavior is central to competent functioning, with limitations in these abilities associated with developmental problems. Parenting appears to influence such self-regulation. Here the differential-susceptibility hypothesis is tested that the more putative "plasticity…

Readers' Emotions: A Plurilingual Perspective

ERIC Educational Resources Information Center

Rivière, Marie

2016-01-01

This article focuses on the differential emotional power of languages in the book-reading practices of plurilingual readers. Within a plurilingual perspective, it aims at adding nuance to the "emotional contexts of learning hypothesis" and the "theory of language embodiment". This qualitative study is based on semi-structured…

Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GAmore » down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.« less

Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

DOE PAGES

Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

2015-01-06

Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GAmore » down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.« less

Adhesion of mesenchymal stem cells to polymer scaffolds occurs via distinct ECM ligands and controls their osteogenic differentiation.

PubMed

Chastain, Sara R; Kundu, Anup K; Dhar, Sanjay; Calvert, Jay W; Putnam, Andrew J

2006-07-01

The osteogenic potential of mesenchymal stem cells (MSCs) cultured on poly(lactide-co-glycolide) (PLGA) or poly(caprolactone) (PCL), two widely used polymeric biomaterials that have been reported to differentially support osteogenic differentiation, was compared in these studies. Here we report that MSCs cultured in 3-D PLGA scaffolds for up to 5 weeks significantly upregulate osteocalcin gene expression levels. By contrast, osteocalcin expression was markedly downregulated in 3-D PCL-based constructs over the same time course. We hypothesized that differential adsorption of extracellular matrix (ECM) proteins present in serum-containing culture medium and subsequent differences in integrin-mediated adhesion are responsible for these differences, and tested this hypothesis using thin (2-D) polymeric films. Supporting this hypothesis, significant amounts of fibronectin and vitronectin deposited onto both materials in serum-containing osteogenic media, with type-I collagen present in lower amounts. Adhesion-blocking studies revealed that MSCs adhere to PCL primarily via vitronectin, while type-I collagen mediates their attachment to PLGA. These adhesive mechanisms correlated with higher levels of alkaline phosphatase (ALP) activity after 2 weeks of monolayer culture on PLGA versus PCL. These data suggest that the initial adhesion of MSCs to PLGA via type-I collagen fosters osteogenesis while adhesion to PCL via vitronectin does not, and stress the need for an improved molecular understanding of cell-ECM interactions in stem cell-based therapies. Copyright (c) 2006 Wiley Periodicals, Inc.

Infant temperamental reactivity, maternal and grandparental sensitivity: Differential susceptibility for behavior problems in China.

PubMed

Xing, Shufen; Zhou, Quan; Archer, Marc; Yue, Jianhong; Wang, Zhengyan

2016-10-01

The differential susceptibility hypothesis suggests that children's innate characteristics and their rearing experiences interact differentially during development. Recently, the study of interactions between infants' temperament and rearing experiences has become a research hotspot. In China, grandparental care is a very common phenomenon, with many infants taken care of by grandparents while mothers are out for work. To investigate whether the associations between maternal and grandmaternal sensitivity, and behavior problems were moderated by infant temperamental reactivity, while the infants were raised by both their mothers and grandmothers. A total of 71 infants (average age of 17.6months), their mothers and grandmothers were included in this study. Maternal sensitivity and grandmaternal sensitivity were assessed with the Maternal Behavior Q-sort-Chinese Version, infants' temperamental reactivity was measured with Carey's Toddler Temperament Questionnaire-Chinese Revision, and infants' behavior problems were measured with the Infant-Toddler Social and Emotional Assessment-Chinese Version. Maternal sensitivity significantly predicted infants' impulsivity and aggression. Infants' temperamental reactivity moderated the effect of maternal sensitivity on infants' general anxiety. In addition, infant temperamental reactivity moderated the impact of grandmaternal sensitivity on infants' separation distress. Our results support the differential susceptibility hypothesis to some extent. Infants with high temperamental reactivity not only suffer more from low maternal and grandmaternal sensitivity, but also benefit more from high maternal and grandmaternal sensitivity as compared to those infants with low temperamental reactivity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Long-term implications of feed energy source in different genetic types of reproductive rabbit females: I. Resource acquisition and allocation.

PubMed

Arnau-Bonachera, A; Cervera, C; Blas, E; Larsen, T; Martínez-Paredes, E; Ródenas, L; Pascual, J J

2017-12-11

To achieve functional but also productive females, we hypothesised that it is possible to modulate acquisition and allocation of animals from different genetic types by varying the main energy source of the diet. To test this hypothesis, we used 203 rabbit females belonging to three genetic types: H (n=66), a maternal line characterised by hyper-prolificacy; LP (n=67), a maternal line characterised by functional hyper-longevity; R (n=79), a paternal line characterised by growth rate. Females were fed with two isoenergetic and isoprotein diets differing in energy source: animal fat (AF) enhancing milk yield; cereal starch (CS) promoting body reserves recovery. Feed intake, weight, perirenal fat thickness (PFT), milk yield and blood traits were controlled during five consecutive reproductive cycles (RCs). Females fed with CS presented higher PFT (+0.2 mm, P0.05), particularly for those fed with AF. Moreover, LP females fed with AF progressively increased PFT across the RC, whereas those fed with CS increased PFT during early lactation (+7.3%; P<0.05), but partially mobilised it during late lactation (-2.8%; P<0.05). Independently of the diet offered, LP females reached weaning with similar PFT. H females fed with either of the two diets followed a similar trajectory throughout the RC. For milk yield, the effect of energy source was almost constant during the whole experiment, except for the first RC of females from the maternal lines (H and LP). These females yielded +34.1% (P<0.05) when fed with CS during this period. Results from this work indicate that the resource acquisition capacity and allocation pattern of rabbit females is different for each genetic type. Moreover, it seems that by varying the main energy source of the diet it is possible to modulate acquisition and allocation of resources of the different genetic types. However, the response of each one depends on its priorities over time.

Automated system function allocation and display format: Task information processing requirements

NASA Technical Reports Server (NTRS)

Czerwinski, Mary P.

1993-01-01

An important consideration when designing the interface to an intelligent system concerns function allocation between the system and the user. The display of information could be held constant, or 'fixed', leaving the user with the task of searching through all of the available information, integrating it, and classifying the data into a known system state. On the other hand, the system, based on its own intelligent diagnosis, could display only relevant information in order to reduce the user's search set. The user would still be left the task of perceiving and integrating the data and classifying it into the appropriate system state. Finally, the system could display the patterns of data. In this scenario, the task of integrating the data is carried out by the system, and the user's information processing load is reduced, leaving only the tasks of perception and classification of the patterns of data. Humans are especially adept at this form of display processing. Although others have examined the relative effectiveness of alphanumeric and graphical display formats, it is interesting to reexamine this issue together with the function allocation problem. Currently, Johnson Space Center is the test site for an intelligent Thermal Control System (TCS), TEXSYS, being tested for use with Space Station Freedom. Expert TCS engineers, as well as novices, were asked to classify several displays of TEXSYS data into various system states (including nominal and anomalous states). Three different display formats were used: fixed, subset, and graphical. The hypothesis tested was that the graphical displays would provide for fewer errors and faster classification times by both experts and novices, regardless of the kind of system state represented within the display. The subset displays were hypothesized to be the second most effective display format/function allocation condition, based on the fact that the search set is reduced in these displays. Both the subset and the graphic display conditions were hypothesized to be processed more efficiently than the fixed display conditions.

How does warming affect carbon allocation, respiration and residence time in trees? An isotope tracer approach in a eucalypt

NASA Astrophysics Data System (ADS)

Pendall, E.; Drake, J. E.; Furze, M.; Barton, C. V.; Carillo, Y.; Richter, A.; Tjoelker, M. G.

2017-12-01

Climate warming has the potential to alter the balance between photosynthetic carbon assimilation and respiratory losses in forest trees, leading to uncertainty in predicting their future physiological functioning. In a previous experiment, warming decreased canopy CO2 assimilation (A) rates of Eucalyptus tereticornis trees, but respiration (R) rates were usually not significantly affected, due to physiological acclimation to temperature. This led to a slight increase in (R/A) and thus decrease in plant carbon use efficiency with climate warming. In contrast to carbon fluxes, the effect of warming on carbon allocation and residence time in trees has received less attention. We conducted a study to test the hypothesis that warming would decrease the allocation of C belowground owing to reduced cost of nutrient uptake. E. parramattensis trees were grown in the field in unique whole-tree chambers operated at ambient and ambient +3 °C temperature treatments (n=3 per treatment). We applied a 13CO2 pulse and followed the label in CO2 respired from leaves, roots, canopy and soil, in plant sugars, and in rhizosphere microbes over a 3-week period in conjunction with measurements of tree growth. The 9-m tall, 57 m3 whole-tree chambers were monitored for CO2 concentrations in independent canopy and below ground (root and soil) compartments; periodic monitoring of δ13C values in air in the compartments allowed us to quantify the amount of 13CO2 assimilated and respired by each tree. Warmed trees grew faster and assimilated more of the label than control trees, but the 13C allocation to canopy, root and soil respiration was not altered. However, warming appeared to reduce the residence time of carbon respired from leaves, and especially from roots and soil, indicating that autotrophic respiration has the potential to feedback to climate change. This experiment provides insights into how warming may affect the fate of assimilated carbon from the leaf to the ecosystem scale.

Can gas exchange dynamics predict non-structural carbohydrate use under drought stress?

NASA Astrophysics Data System (ADS)

Kannenberg, S.; Phillips, R.

2016-12-01

A recent conceptual framework for understanding tree drought responses characterizes species along a continuum from isohydry to anisohydry, with theory predicting that isohydric and anisohydric trees should display different carbon (C) allocation patterns under drought conditions. We tested the hypothesis that the trade-offs inherent in the isohydry-anisohydry framework (i.e., C starvation vs. hydraulic failure) necessitate different allocation patterns to non-structural carbohydrates (NSCs), growth, and respiration. Specifically, we hypothesized that isohydric trees would decrease NSC stores and growth in the face of reduced incoming photoassimilate, whereas anisohydric trees would maintain assimilation, growth, and NSC pools due to decreased demand for stored metabolic C and enhanced osmoregulatory needs. To test this, we subjected saplings of Liriodendron tulipifera (an isohydric tree) and Quercus alba (an anisohydric tree) to a six week drought in the greenhouse, and measured assimilation, leaf water potential (midday and predawn), growth, leaf dark respiration and NSCs (both sugars and starch in aboveground and belowground tissues) in control and droughted plants. Overall, we confirmed that the isohydric and anisohydric species used NSCs differently during drought. In most tissues, both species had similar responses of NSCs to drought: starch NSCs were maintained or decreased while sugar NSCs tended to increase. Stem NSCs were a notable exception, as L. tulipifera decreased total NSC to almost zero while NSCs in Q. alba remained constant. This depletion of stem NSC in L. tulipifera was offset by increases in other tissues, however, resulting in no net change to total NSC during the drought. In contrast, Q. alba increased total NSC. Interestingly, Q. alba also decreased assimilation and growth, indicating a potential trade-off between NSC and biomass allocation. Our results show that NSCs in different tissues may have contrasting uses as storage or osmoregulatory compounds. Collectively, our work also demonstrates that NSC dynamics may be coupled to hydraulic strategies and proposes a link between a tree's degree of isohydry, C allocation patterns, and potential mechanisms of tree mortality.

Does plant apparency matter? Thirty years of data provide limited support but reveal clear patterns of the effects of plant chemistry on herbivores.

PubMed

Smilanich, Angela M; Fincher, R Malia; Dyer, Lee A

2016-05-01

According to the plant-apparency hypothesis, apparent plants allocate resources to quantitative defenses that negatively affect generalist and specialist herbivores, while unapparent plants invest more in qualitative defenses that negatively affect nonadapted generalists. Although this hypothesis has provided a useful framework for understanding the evolution of plant chemical defense, there are many inconsistencies surrounding associated predictions, and it has been heavily criticized and deemed obsolete. We used a hierarchical Bayesian meta-analysis model to test whether defenses from apparent and unapparent plants differ in their effects on herbivores. We collected a total of 225 effect sizes from 158 published papers in which the effects of plant chemistry on herbivore performance were reported. As predicted by the plant-apparency hypothesis, we found a prevalence of quantitative defenses in woody plants and qualitative defenses in herbaceous plants. However, the detrimental impacts of qualitative defenses were more effective against specialists than generalists, and the effects of chemical defenses did not significantly differ between specialists and generalists for woody or herbaceous plants. A striking pattern that emerged from our data was a pervasiveness of beneficial effects of secondary metabolites on herbivore performance, especially generalists. This pattern provides evidence that herbivores are evolving effective counteradaptations to putative plant defenses. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Objects predict fixations better than early saliency.

PubMed

Einhäuser, Wolfgang; Spain, Merrielle; Perona, Pietro

2008-11-20

Humans move their eyes while looking at scenes and pictures. Eye movements correlate with shifts in attention and are thought to be a consequence of optimal resource allocation for high-level tasks such as visual recognition. Models of attention, such as "saliency maps," are often built on the assumption that "early" features (color, contrast, orientation, motion, and so forth) drive attention directly. We explore an alternative hypothesis: Observers attend to "interesting" objects. To test this hypothesis, we measure the eye position of human observers while they inspect photographs of common natural scenes. Our observers perform different tasks: artistic evaluation, analysis of content, and search. Immediately after each presentation, our observers are asked to name objects they saw. Weighted with recall frequency, these objects predict fixations in individual images better than early saliency, irrespective of task. Also, saliency combined with object positions predicts which objects are frequently named. This suggests that early saliency has only an indirect effect on attention, acting through recognized objects. Consequently, rather than treating attention as mere preprocessing step for object recognition, models of both need to be integrated.

Population genetic structure of gray wolves (Canis lupus) in a marine archipelago suggests island-mainland differentiation consistent with dietary niche

PubMed Central

2014-01-01

Background Emerging evidence suggests that ecological heterogeneity across space can influence the genetic structure of populations, including that of long-distance dispersers such as large carnivores. On the central coast of British Columbia, Canada, wolf (Canis lupus L., 1758) dietary niche and parasite prevalence data indicate strong ecological divergence between marine-oriented wolves inhabiting islands and individuals on the coastal mainland that interact primarily with terrestrial prey. Local holders of traditional ecological knowledge, who distinguish between mainland and island wolf forms, also informed our hypothesis that genetic differentiation might occur between wolves from these adjacent environments. Results We used microsatellite genetic markers to examine data obtained from wolf faecal samples. Our results from 116 individuals suggest the presence of a genetic cline between mainland and island wolves. This pattern occurs despite field observations that individuals easily traverse the 30 km wide study area and swim up to 13 km among landmasses in the region. Conclusions Natal habitat-biased dispersal (i.e., the preference for dispersal into familiar ecological environments) might contribute to genetic differentiation. Accordingly, this working hypothesis presents an exciting avenue for future research where marine resources or other components of ecological heterogeneity are present. PMID:24915756

Gestational Diabetes Alters Offspring DNA Methylation Profiles in Human and Rat: Identification of Key Pathways Involved in Endocrine System Disorders, Insulin Signaling, Diabetes Signaling, and ILK Signaling.

PubMed

Petropoulos, Sophie; Guillemin, Claire; Ergaz, Zivanit; Dimov, Sergiy; Suderman, Matthew; Weinstein-Fudim, Liza; Ornoy, Asher; Szyf, Moshe

2015-06-01

Gestational diabetes is associated with risk for metabolic disease later in life. Using a cross-species approach in rat and humans, we examined the hypothesis that gestational diabetes during pregnancy triggers changes in the methylome of the offspring that might be mediating these risks. We show in a gestation diabetes rat model, the Cohen diabetic rat, that gestational diabetes triggers wide alterations in DNA methylation in the placenta in both candidate diabetes genes and genome-wide promoters, thus providing evidence for a causal relationship between diabetes during pregnancy and DNA methylation alterations. There is a significant overlap between differentially methylated genes in the placenta and the liver of the rat offspring. Several genes differentially methylated in rat placenta exposed to maternal diabetes are also differentially methylated in the human placenta of offspring exposed to gestational diabetes in utero. DNA methylation changes inversely correlate with changes in expression. The changes in DNA methylation affect known functional gene pathways involved in endocrine function, metabolism, and insulin responses. These data provide support to the hypothesis that early-life exposures and their effects on metabolic disease are mediated by DNA methylation changes. This has important diagnostic and therapeutic implications.

Geometry of Optimal Paths around Focal Singular Surfaces in Differential Games

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melikyan, Arik; Bernhard, Pierre

2005-06-15

We investigate a special type of singularity in non-smooth solutions of first-order partial differential equations, with emphasis on Isaacs' equation. This type, called focal manifold, is characterized by the incoming trajectory fields on the two sides and a discontinuous gradient. We provide a complete set of constructive equations under various hypotheses on the singularity, culminating with the case where no a priori hypothesis on its geometry is known, and where the extremal trajectory fields need not be collinear. We show two examples of differential games exhibiting non-collinear fields of extremal trajectories on the focal manifold, one with a transversal approachmore » and one with a tangential approach.« less

Inference for High-dimensional Differential Correlation Matrices.

PubMed

Cai, T Tony; Zhang, Anru

2016-01-01

Motivated by differential co-expression analysis in genomics, we consider in this paper estimation and testing of high-dimensional differential correlation matrices. An adaptive thresholding procedure is introduced and theoretical guarantees are given. Minimax rate of convergence is established and the proposed estimator is shown to be adaptively rate-optimal over collections of paired correlation matrices with approximately sparse differences. Simulation results show that the procedure significantly outperforms two other natural methods that are based on separate estimation of the individual correlation matrices. The procedure is also illustrated through an analysis of a breast cancer dataset, which provides evidence at the gene co-expression level that several genes, of which a subset has been previously verified, are associated with the breast cancer. Hypothesis testing on the differential correlation matrices is also considered. A test, which is particularly well suited for testing against sparse alternatives, is introduced. In addition, other related problems, including estimation of a single sparse correlation matrix, estimation of the differential covariance matrices, and estimation of the differential cross-correlation matrices, are also discussed.

Dynamic Hydrostatic Pressure Promotes Differentiation of Human Dental Pulp Stem Cells

PubMed Central

Yu, V; Damek-Poprawa, M.; Nicoll, S. B.; Akintoye, S.O.

2009-01-01

The masticatory apparatus absorbs high occlusal forces, but uncontrolled parafunctional or orthodontic forces damage periodontal ligament (PDL), cause pulpal calcification, pulp necrosis and tooth loss. Morphology and functional differentiation of connective tissue cells can be controlled by mechanical stimuli but effects of uncontrolled forces on intra-pulpal homeostasis and ability of dental pulp stem cells (DPSCs) to withstand direct external forces are unclear. Using dynamic hydrostatic pressure (HSP), we tested the hypothesis that direct HSP disrupts DPSC survival and odontogenic differentiation. DPSCs from four teenage patients were subjected to HSP followed by assessment of cell adhesion, survival and recovery capacity based on odontogenic differentiation, mineralization and responsiveness to bone morphogenetic protein-2 (BMP-2). HSP down-regulated DPSC adhesion and survival but promoted differentiation by increasing mineralization, in vivo hard tissue regeneration and BMP-2 responsiveness despite reduced cell numbers. HSP-treated DPSCs displayed enhanced odontogenic differentiation, an indication of favorable recovery from HSP-induced cellular stress. PMID:19555657

Xenobiotics that affect oxidative phosphorylation alter differentiation of human adipose-derived stem cells at concentrations that are found in human blood

PubMed Central

Llobet, Laura; Toivonen, Janne M.; Montoya, Julio; Ruiz-Pesini, Eduardo; López-Gallardo, Ester

2015-01-01

ABSTRACT Adipogenesis is accompanied by differentiation of adipose tissue-derived stem cells to adipocytes. As part of this differentiation, biogenesis of the oxidative phosphorylation system occurs. Many chemical compounds used in medicine, agriculture or other human activities affect oxidative phosphorylation function. Therefore, these xenobiotics could alter adipogenesis. We have analyzed the effects on adipocyte differentiation of some xenobiotics that act on the oxidative phosphorylation system. The tested concentrations have been previously reported in human blood. Our results show that pharmaceutical drugs that decrease mitochondrial DNA replication, such as nucleoside reverse transcriptase inhibitors, or inhibitors of mitochondrial protein synthesis, such as ribosomal antibiotics, diminish adipocyte differentiation and leptin secretion. By contrast, the environmental chemical pollutant tributyltin chloride, which inhibits the ATP synthase of the oxidative phosphorylation system, can promote adipocyte differentiation and leptin secretion, leading to obesity and metabolic syndrome as postulated by the obesogen hypothesis. PMID:26398948

Environmental hormones and their impacts on sex differentiation in fathead minnows

EPA Science Inventory

Runoff from lands fertilized with animal manure from concentrated animal feeding operations (CAFOs) is a source of hormones to surface water. To test the hypothesis that juvenile fathead minnows exposed to sex steroids singly and in a “typical” CAFO mixture while undergoing sex...

Listeners' Comprehension of Uptalk in Spontaneous Speech

ERIC Educational Resources Information Center

Tomlinson, John M., Jr.; Tree, Jean E. Fox

2011-01-01

Listeners' comprehension of phrase final rising pitch on declarative utterances, or "uptalk", was examined to test the hypothesis that prolongations might differentiate conflicting functions of rising pitch. In Experiment 1 we found that listeners rated prolongations as indicating more speaker uncertainty, but that rising pitch was unrelated to…

Aspects of Migration in an Advanced Industrial Society.

ERIC Educational Resources Information Center

Wilson, Franklin D.

This paper evaluates the hypothesis that patterns of migration within and between the metropolitan and nonmetropolitan sectors and between regions, and migrant/nonmigrant differentials in education attainment during the 1935-1980 period of United States history reflect historical differences in socioeconomic development and settlement patterns.…

Free amino acids - determinant of sugarcane resistance/susceptibility to stalk borer and sap feeders

USDA-ARS?s Scientific Manuscript database

Two relatively new key species in Louisiana that conform to the plant stress hypothesis are the Mexican rice borer, Eoreuma loftini (Dyar) and the sugarcane aphid, Melanaphis sacchari (Zehntner). High performance liquid chromatography differentiated insect resistant and susceptible sugarcane cultiva...

The efficacy of self-paced study in multitrial learning.

PubMed

de Jonge, Mario; Tabbers, Huib K; Pecher, Diane; Jang, Yoonhee; Zeelenberg, René

2015-05-01

In 2 experiments we investigated the efficacy of self-paced study in multitrial learning. In Experiment 1, native speakers of English studied lists of Dutch-English word pairs under 1 of 4 imposed fixed presentation rate conditions (24 × 1 s, 12 × 2 s, 6 × 4 s, or 3 × 8 s) and a self-paced study condition. Total study time per list was equated for all conditions. We found that self-paced study resulted in better recall performance than did most of the fixed presentation rates, with the exception of the 12 × 2 s condition, which did not differ from the self-paced condition. Additional correlational analyses suggested that the allocation of more study time to difficult pairs than to easy pairs might be a beneficial strategy for self-paced learning. Experiment 2 was designed to test this hypothesis. In 1 condition, participants studied word pairs in a self-paced fashion without any restrictions. In the other condition, participants studied word pairs in a self-paced fashion but total study time per item was equated. The results showed that allowing self-paced learners to freely allocate study time over items resulted in better recall performance. (c) 2015 APA, all rights reserved).

Neuroscientific evidence for defensive avoidance of fear appeals.

PubMed

Kessels, Loes T E; Ruiter, Robert A C; Wouters, Liesbeth; Jansma, Bernadette M

2014-04-01

Previous studies indicate that people respond defensively to threatening health information, especially when the information challenges self-relevant goals. The authors investigated whether reduced acceptance of self-relevant health risk information is already visible in early attention allocation processes. In two experimental studies, participants were watching high- and low-threat health commercials, and at the same time had to pay attention to specific odd auditory stimuli in a sequence of frequent auditory stimuli (odd ball paradigm). The amount of attention allocation was measured by recording event-related brain potentials (i.e., P300 ERPs) and reaction times. Smokers showed larger P300 amplitudes in response to the auditory targets while watching high-threat instead of low-threat anti-smoking commercials. In contrast, non-smokers showed smaller P300 amplitudes during watching high as opposed to low threat anti-smoking commercials. In conclusion, the findings provide further neuroscientific support for the hypothesis that threatening health information causes more avoidance responses among those for whom the health threat is self-relevant. © 2014 The Authors. International Journal of Psychology published by John Wiley © Sons Ltd on behalf of International Union of Psychological Science.

Napping reduces emotional attention bias during early childhood.

PubMed

Cremone, Amanda; Kurdziel, Laura B F; Fraticelli-Torres, Ada; McDermott, Jennifer M; Spencer, Rebecca M C

2017-07-01

Sleep loss alters processing of emotional stimuli in preschool-aged children. However, the mechanism by which sleep modifies emotional processing in early childhood is unknown. We tested the hypothesis that a nap, compared to an equivalent time spent awake, reduces biases in attention allocation to affective information. Children (n = 43; M = 55.40 months, SD = 8.05 months) completed a Dot Probe task, which provides a measure of attention biases to emotional stimuli, following a mid-day nap and an equivalent interval spent awake. No emotional attention biases emerged when children napped. However, when nap-deprived, children exhibited biases towards negative and positive stimuli. This emotional bias after wake was greater in children who napped habitually. Gender differences also emerged such that females were more attentive to positive emotional stimuli whereas males showed heightened attention to negative emotional stimuli, regardless of having napped or not. Moreover, greater slow wave activity (SWA) during the nap was associated with faster responding, which suggests that SWA may promote efficiency of attention allocation. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=JIoZ8mzxQgg. © 2016 John Wiley & Sons Ltd.

Is there a cost to resprouting? Seedling growth rate and drought tolerance in sprouting and nonsprouting Ceanothus (Rhamnaceae)

USGS Publications Warehouse

Schwilk, D.W.; Ackerly, D.D.

2005-01-01

Many woody plant species that depend upon fire-cued seed germination lack the ability to resprout. As the ability to resprout is widely assumed to be the ancestral condition in most plant groups, the failure to sprout is an evolutionary derived trait. Models for the evolutionary loss of sprouting assume a trade-off between seedling success and vegetative resprouting ability of adults. Such models require higher seedling success rates in nonsprouters than in sprouters. On the other hand, there seem to be few a priori reasons why a strong sprouter might not also have highly competitive post-fire seedlings. To test the hypothesis that nonsprouting plants have higher growth rates and/or drought survival, we grew seedlings of Ceanothus tomentosus from sprouting and nonsprouting populations in a common garden experiment. Each of these C. tomentosus populations was paired with a sympatric Ceanothus species that differed in resprouting ability. Sprouters exhibited greater allocation to root carbohydrate storage than did nonsprouters, but overall relative growth rates did not differ. Nonsprouters had earlier onset of flowering. These results provide mixed support for models of a sprouting/nonsprouting allocation trade-off.

Viability costs of reproduction and behavioral compensation in western mosquitofish (Gambusia affinis).

PubMed

Laidlaw, Clinton T; Condon, Jacob M; Belk, Mark C

2014-01-01

The cost of reproduction hypothesis suggests that current reproduction has inherent tradeoffs with future reproduction. These tradeoffs can be both in the form of energy allocated to current offspring as opposed to somatic maintenance and future reproduction (allocation costs), or as an increase in mortality as a result of morphological or physiological changes related to reproduction (viability costs). Individuals may be able to decrease viability costs by altering behavior. Female western mosquitofish, Gambusia affinis experience a reduction in swimming ability as a consequence of pregnancy. We test for a viability cost of reproduction, and for behavioral compensation in pregnant female G. affinis by measuring survival of females in early and later stages of pregnancy when exposed to predation. Late-stage pregnant females experience a 70% greater probability of mortality compared to early-stage pregnant females. The presence of a refuge roughly doubled the odds of survival of both early and late-stage pregnant females. However, there was no interaction between refuge availability and stage of pregnancy. These data do not provide evidence for behavioral compensation by female G. affinis for elevated viability costs incurred during later stages of pregnancy. Behavioral compensation may be constrained by other aspects of the cost of reproduction.

Chromosomal locations and modes of action of genes of the retinoid (vitamin A) system support their involvement in the etiology of schizophrenia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodman, A.B.

1995-08-14

Vitamin A (retinoid), an essential nutrient for fetal and subsequent mammalian development, is involved in gene expression, cell differentiation, proliferation, migration, and death. Retinoic acid (RA) the morphogenic derivative of vitamin A is highly teratogenic. In humans retinoid excess or deficit can result in brain anomalies and psychosis. This review discusses chromosomal loci of genes that control the retinoid cascade in relation to some candidate genes in schizophrenia. The paper relates the knowledge about the transport, delivery, and action of retinoids to what is presently known about the pathology of schizophrenia, with particular reference to the dopamine hypothesis, neurotransmitters, themore » glutamate hypothesis, neurotransmitters, the glutamate hypothesis, retinitis pigmentosa, dermatologic disorders, and craniofacial anomalies. 201 refs., 1 tab.« less

Autosomal STRs provide genetic evidence for the hypothesis that Tai people originate from southern China.

PubMed

Sun, Hao; Zhou, Chi; Huang, Xiaoqin; Lin, Keqin; Shi, Lei; Yu, Liang; Liu, Shuyuan; Chu, Jiayou; Yang, Zhaoqing

2013-01-01

Tai people are widely distributed in Thailand, Laos and southwestern China and are a large population of Southeast Asia. Although most anthropologists and historians agree that modern Tai people are from southwestern China and northern Thailand, the place from which they historically migrated remains controversial. Three popular hypotheses have been proposed: northern origin hypothesis, southern origin hypothesis or an indigenous origin. We compared the genetic relationships between the Tai in China and their "siblings" to test different hypotheses by analyzing 10 autosomal microsatellites. The genetic data of 916 samples from 19 populations were analyzed in this survey. The autosomal STR data from 15 of the 19 populations came from our previous study (Lin et al., 2010). 194 samples from four additional populations were genotyped in this study: Han (Yunnan), Dai (Dehong), Dai (Yuxi) and Mongolian. The results of genetic distance comparisons, genetic structure analyses and admixture analyses all indicate that populations from northern origin hypothesis have large genetic distances and are clearly differentiated from the Tai. The simulation-based ABC analysis also indicates this. The posterior probability of the northern origin hypothesis is just 0.04 [95%CI: (0.01-0.06)]. Conversely, genetic relationships were very close between the Tai and populations from southern origin or an indigenous origin hypothesis. Simulation-based ABC analyses were also used to distinguish the southern origin hypothesis from the indigenous origin hypothesis. The results indicate that the posterior probability of the southern origin hypothesis [0.640, 95%CI: (0.524-0.757)] is greater than that of the indigenous origin hypothesis [0.324, 95%CI: (0.211-0.438)]. Therefore, we propose that the genetic evidence does not support the hypothesis of northern origin. Our genetic data indicate that the southern origin hypothesis has higher probability than the other two hypotheses statistically, suggesting that the Tai people most likely originated from southern China.

The evolution of postpairing male mate choice.

PubMed

Lyu, Nan; Servedio, Maria R; Lloyd, Huw; Sun, Yue-Hua

2017-06-01

An increasing number of empirical studies in animals have demonstrated male mate choice. However, little is known about the evolution of postpairing male choice, specifically which occurs by differential allocation of male parental care in response to female signals. We use a population genetic model to examine whether such postpairing male mate choice can evolve when males face a trade-off between parental care and extra-pair copulations (EPCs). Specifically, we assume that males allocate more effort to providing parental care when mated to preferred (signaling) females, but they are then unable to allocate additional effort to seek EPCs. We find that both male preference and female signaling can evolve in this situation, under certain conditions. First, this evolution requires a relatively large difference in parental investment between males mated to preferred versus nonpreferred females. Second, whether male choice and female signaling alleles become fixed in a population versus cycle in their frequencies depends on the additional fecundity benefits from EPCs that are gained by choosy males. Third, less costly female signals enable both signaling and choice alleles to evolve under more relaxed conditions. Our results also provide a new insight into the evolution of sexual conflict over parental care. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Evolutionary public health: introducing the concept.

PubMed

Wells, Jonathan C K; Nesse, Randolph M; Sear, Rebecca; Johnstone, Rufus A; Stearns, Stephen C

2017-07-29

The emerging discipline of evolutionary medicine is breaking new ground in understanding why people become ill. However, the value of evolutionary analyses of human physiology and behaviour is only beginning to be recognised in the field of public health. Core principles come from life history theory, which analyses the allocation of finite amounts of energy between four competing functions-maintenance, growth, reproduction, and defence. A central tenet of evolutionary theory is that organisms are selected to allocate energy and time to maximise reproductive success, rather than health or longevity. Ecological interactions that influence mortality risk, nutrient availability, and pathogen burden shape energy allocation strategies throughout the life course, thereby affecting diverse health outcomes. Public health interventions could improve their own effectiveness by incorporating an evolutionary perspective. In particular, evolutionary approaches offer new opportunities to address the complex challenges of global health, in which populations are differentially exposed to the metabolic consequences of poverty, high fertility, infectious diseases, and rapid changes in nutrition and lifestyle. The effect of specific interventions is predicted to depend on broader factors shaping life expectancy. Among the important tools in this approach are mathematical models, which can explore probable benefits and limitations of interventions in silico, before their implementation in human populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neural bases of antisocial behavior: a voxel-based meta-analysis

PubMed Central

Inokuchi, Ryota; Nakao, Tomohiro; Yamasue, Hidenori

2014-01-01

Individuals with antisocial behavior place a great physical and economic burden on society. Deficits in emotional processing have been recognized as a fundamental cause of antisocial behavior. Emerging evidence also highlights a significant contribution of attention allocation deficits to such behavior. A comprehensive literature search identified 12 studies that were eligible for inclusion in the meta-analysis, which compared 291 individuals with antisocial problems and 247 controls. Signed Differential Mapping revealed that compared with controls, gray matter volume (GMV) in subjects with antisocial behavior was reduced in the right lentiform nucleus (P < 0.0001), left insula (P = 0.0002) and left frontopolar cortex (FPC) (P = 0.0006), and was increased in the right fusiform gyrus (P < 0.0001), right inferior parietal lobule (P = 0.0003), right superior parietal lobule (P = 0.0004), right cingulate gyrus (P = 0.0004) and the right postcentral gyrus (P = 0.0004). Given the well-known contributions of limbic and paralimbic areas to emotional processing, the observed reductions in GMV in these regions might represent neural correlates of disturbance in emotional processing underlying antisocial behavior. Previous studies have suggested an FPC role in attention allocation during emotional processing. Therefore, GMV deviations in this area may constitute a neural basis of deficits in attention allocation linked with antisocial behavior. PMID:23926170

The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation.

PubMed

Miyamoto, Daisuke; Hirai, Daichi; Murayama, Masanori

2017-01-01

Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5-4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation. During slow wave sleep, inter-areal interactions between the cortex and hippocampus (HC) have been proposed to consolidate declarative memory; however, interactions for non-declarative (HC-independent) memory remain largely uninvestigated. We recently showed that the directional influence in a slow-wave range through a top-down cortical long-range circuit is involved in the consolidation of non-declarative memory. At the synaptic level, the average cortical synaptic strength is known to be potentiated during wakefulness and depressed during sleep. Moreover, learning causes plasticity in a subset of synapses, allocating memory to them. Sleep may help to differentiate synaptic strength between allocated and non-allocated synapses (i.e., improving the signal-to-noise ratio, which may facilitate memory consolidation). Herein, we offer perspectives on inter-areal interactions and synaptic plasticity for memory consolidation during sleep.

The Roles of Cortical Slow Waves in Synaptic Plasticity and Memory Consolidation

PubMed Central

Miyamoto, Daisuke; Hirai, Daichi; Murayama, Masanori

2017-01-01

Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5–4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation. During slow wave sleep, inter-areal interactions between the cortex and hippocampus (HC) have been proposed to consolidate declarative memory; however, interactions for non-declarative (HC-independent) memory remain largely uninvestigated. We recently showed that the directional influence in a slow-wave range through a top-down cortical long-range circuit is involved in the consolidation of non-declarative memory. At the synaptic level, the average cortical synaptic strength is known to be potentiated during wakefulness and depressed during sleep. Moreover, learning causes plasticity in a subset of synapses, allocating memory to them. Sleep may help to differentiate synaptic strength between allocated and non-allocated synapses (i.e., improving the signal-to-noise ratio, which may facilitate memory consolidation). Herein, we offer perspectives on inter-areal interactions and synaptic plasticity for memory consolidation during sleep. PMID:29213231

Does carbon availability control temporal dynamics of radial growth in Norway spruce (Picea abies)?

NASA Astrophysics Data System (ADS)

Oberhuber, Walter; Gruber, Andreas; Swidrak, Irene

2015-04-01

Intra-annual dynamics of cambial activity and wood formation of coniferous species exposed to soil dryness revealed early culmination of maximum growth in late spring prior to occurrence of more favourable environmental conditions, i.e., repeated high rainfall events during summer (Oberhuber et al. 2014). Because it is well known that plants can adjust carbon allocation patterns to optimize resource uptake under prevailing environmental constraints, we hypothesize that early decrease in radial stem growth is an adaptation to cope with drought stress, which might require an early switch of carbon allocation to belowground organs. Physical blockage of carbon transport in the phloem through girdling causes accumulation and depletion of carbohydrates above and below the girdle, respectively, making this method quite appropriate to investigate carbon relationships in trees. Hence, in a common garden experiment we will manipulate the carbon status of Norway spruce (Picea abies) saplings by phloem blockage at different phenological stages during the growing season. We will present the methodological approach and first results of the study aiming to test the hypothesis that carbon status of the tree affects temporal dynamics of cambial activity and wood formation in conifers under drought. Acknowledgment The research is funded by the Austrian Science Fund (FWF): P25643-B16 "Carbon allocation and growth of Scots pine". Reference Oberhuber W, A Gruber, W Kofler, I Swidrak (2014) Radial stem growth in response to microclimate and soil moisture in a drought-prone mixed coniferous forest at an inner Alpine site. Eur J For Res 133:467-479.

Germination season and watering regime, but not seed morph, affect life history traits in a cold desert diaspore-heteromorphic annual.

PubMed

Lu, Juan J; Tan, Dun Y; Baskin, Jerry M; Baskin, Carol C

2014-01-01

Seed morph, abiotic conditions and time of germination can affect plant fitness, but few studies have tested their combined effects on plasticity of plant life history traits. Thus, we tested the hypothesis that seed morph, germination season and watering regime influence phenotypic expression of post-germination life history traits in the diaspore-heteromorphic cold desert winter annual/spring ephemeral Diptychocarpus strictus. The two seed morphs were sown in watered and non-watered plots in late summer, and plants derived from them were watered or not-watered throughout the study. Seed morph did not affect phenology, growth and morphology, survival, dry mass accumulation and allocation or silique and seed production. Seeds in watered plots germinated in autumn (AW) and spring (SW) but only in spring for non-watered plots (SNW). A high percentage of AW, SW and SNW plants survived and reproduced, but flowering date and flowering period of autumn- vs. spring-germinated plants differed. Dry mass also differed with germination season/watering regime (AW > SW > SNW). Number of siliques and seeds increased with plant size (AW > SW > SNW), whereas percent dry mass allocated to reproduction was higher in small plants: SNW > SW > AW. Thus, although seed morph did not affect the expression of life history traits, germination season and watering regime significantly affected phenology, plant size and accumulation and allocation of biomass to reproduction. Flexibility throughout the life cycle of D. strictus is an adaptation to the variation in timing and amount of rainfall in its cold desert habitat.

Allocation to leaf area and sapwood area affects water relations of co-occurring savanna and forest trees.

PubMed

Gotsch, Sybil G; Geiger, Erika L; Franco, Augusto C; Goldstein, Guillermo; Meinzer, Frederick C; Hoffmann, William A

2010-06-01

Water availability is a principal factor limiting the distribution of closed-canopy forest in the seasonal tropics, suggesting that forest tree species may not be well adapted to cope with seasonal drought. We studied 11 congeneric species pairs, each containing one forest and one savanna species, to test the hypothesis that forest trees have a lower capacity to maintain seasonal homeostasis in water relations relative to savanna species. To quantify this, we measured sap flow, leaf water potential (Psi(L)), stomatal conductance (g (s)), wood density, and Huber value (sapwood area:leaf area) of the 22 study species. We found significant differences in the water relations of these two species types. Leaf area specific hydraulic conductance of the soil/root/leaf pathway (G (t)) was greater for savanna species than forest species. The lower G (t) of forest trees resulted in significantly lower Psi(L) and g (s) in the late dry season relative to savanna trees. The differences in G (t) can be explained by differences in biomass allocation of savanna and forest trees. Savanna species had higher Huber values relative to forest species, conferring greater transport capacity on a leaf area basis. Forest trees have a lower capacity to maintain homeostasis in Psi(L) due to greater allocation to leaf area relative to savanna species. Despite significant differences in water relations, relationships between traits such as wood density and minimum Psi(L) were indistinguishable for the two species groups, indicating that forest and savanna share a common axis of water-use strategies involving multiple traits.

Children’s Reasoning about Distributive and Retributive Justice across Development

PubMed Central

Smith, Craig E.; Warneken, Felix

2016-01-01

Research on distributive justice indicates that preschool-age children take issues of equity and merit into account when distributing desirable items, but that they often prefer to see desirable items allocated equally in third-party tasks. By contrast, less is known about the development of retributive justice. In a study with 4–10-year-old children (n = 123) and adults (n = 93), we directly compared the development of reasoning about distributive and retributive justice. We measured the amount of rewards or punishments that participants allocated to recipients who differed in the amount of good or bad things they had done. We also measured judgements about collective rewards and punishments. We found that the developmental trajectory of thinking about retributive justice parallels that of distributive justice. The 4–5-year-olds were the most likely to prefer equal distributions of both rewarding and aversive consequences; older children and adults preferred deservingness-based allocations. The 4–5-year-olds were also most likely to judge collective rewards and punishments as fair; this tendency declined with increasing age. Our results also highlight the extent to which the notion of desert influences thinking about distributive and retributive justice; desert was considered equally when participants allocated reward and punishments, but in judgments about collective discipline, participants focused more on desert in cases of punishment compared to reward. We discuss our results in relation to theories about preferences for equality vs. equity, theories about how desert is differentially weighed across distributive and retributive justice, and in relation to the literature on moral development and fairness. PMID:26845506

Revisiting the continuum hypothesis: toward an in-depth exploration of executive functions in korsakoff syndrome.

PubMed

Brion, Mélanie; Pitel, Anne-Lise; Beaunieux, Hélène; Maurage, Pierre

2014-01-01

Korsakoff syndrome (KS) is a neurological state mostly caused by alcohol-dependence and leading to disproportionate episodic memory deficits. KS patients present more severe anterograde amnesia than Alcohol-Dependent Subjects (ADS), which led to the continuum hypothesis postulating a progressive increase in brain and cognitive damages during the evolution from ADS to KS. This hypothesis has been extensively examined for memory but is still debated for other abilities, notably executive functions (EF). EF have up to now been explored by unspecific tasks in KS, and few studies explored their interactions with memory. Exploring EF in KS by specific tasks based on current EF models could thus renew the exploration of the continuum hypothesis. This paper will propose a research program aiming at: (1) clarifying the extent of executive dysfunctions in KS by tasks focusing on specific EF subcomponents; (2) determining the differential EF deficits in ADS and KS; (3) exploring EF-memory interactions in KS with innovative tasks. At the fundamental level, this exploration will test the continuum hypothesis beyond memory. At the clinical level, it will propose new rehabilitation tools focusing on the EF specifically impaired in KS.

Revisiting the Continuum Hypothesis: Toward an In-Depth Exploration of Executive Functions in Korsakoff Syndrome

PubMed Central

Brion, Mélanie; Pitel, Anne-Lise; Beaunieux, Hélène; Maurage, Pierre

2014-01-01

Korsakoff syndrome (KS) is a neurological state mostly caused by alcohol-dependence and leading to disproportionate episodic memory deficits. KS patients present more severe anterograde amnesia than Alcohol-Dependent Subjects (ADS), which led to the continuum hypothesis postulating a progressive increase in brain and cognitive damages during the evolution from ADS to KS. This hypothesis has been extensively examined for memory but is still debated for other abilities, notably executive functions (EF). EF have up to now been explored by unspecific tasks in KS, and few studies explored their interactions with memory. Exploring EF in KS by specific tasks based on current EF models could thus renew the exploration of the continuum hypothesis. This paper will propose a research program aiming at: (1) clarifying the extent of executive dysfunctions in KS by tasks focusing on specific EF subcomponents; (2) determining the differential EF deficits in ADS and KS; (3) exploring EF-memory interactions in KS with innovative tasks. At the fundamental level, this exploration will test the continuum hypothesis beyond memory. At the clinical level, it will propose new rehabilitation tools focusing on the EF specifically impaired in KS. PMID:25071526

The origin of conodonts and of vertebrate mineralized skeletons

USGS Publications Warehouse

Murdock, Duncan J.E.; Dong, Xi-Ping; Repetski, John E.; Marone, Federica; Stampanoni, Marco; Donoghue, Philip C.J.

2013-01-01

Conodonts are an extinct group of jawless vertebrates whose tooth-like elements are the earliest instance of a mineralized skeleton in the vertebrate lineage, inspiring the ‘inside-out’ hypothesis that teeth evolved independently of the vertebrate dermal skeleton and before the origin of jaws. However, these propositions have been based on evidence from derived euconodonts. Here we test hypotheses of a paraconodont ancestry of euconodonts using synchrotron radiation X-ray tomographic microscopy to characterize and compare the microstructure of morphologically similar euconodont and paraconodont elements. Paraconodonts exhibit a range of grades of structural differentiation, including tissues and a pattern of growth common to euconodont basal bodies. The different grades of structural differentiation exhibited by paraconodonts demonstrate the stepwise acquisition of euconodont characters, resolving debate over the relationship between these two groups. By implication, the putative homology of euconodont crown tissue and vertebrate enamel must be rejected as these tissues have evolved independently and convergently. Thus, the precise ontogenetic, structural and topological similarities between conodont elements and vertebrate odontodes appear to be a remarkable instance of convergence. The last common ancestor of conodonts and jawed vertebrates probably lacked mineralized skeletal tissues. The hypothesis that teeth evolved before jaws and the inside-out hypothesis of dental evolution must be rejected; teeth seem to have evolved through the extension of odontogenic competence from the external dermis to internal epithelium soon after the origin of jaws.

Brood desertion by female shorebirds: a test of the differential parental capacity hypothesis on Kentish plovers.

PubMed Central

Amat, J A; Visser, G H; Pérez-Hurtado, A; Arroyo, G M

2000-01-01

The aim of this study was to examine whether the energetic costs of reproduction explain offspring desertion by female shorebirds, as is suggested by the differential parental capacity hypothesis. A prediction of the hypothesis is that, in species with biparental incubation in which females desert from brood care after hatching, the body condition of females should decline after laying to a point at which their body reserves are too low for continuing parental care. We tested this prediction on Kentish plovers (Charadrius alexandrinus) in which both sexes incubate but the females desert from brood care before the chicks fledge. We found no changes in either the body masses or body compositions of both individual male and female plovers from early incubation and throughout early chick rearing. Furthermore, the timing of brood desertion by females was not affected by their body condition. Neither did we find gender differences in the energetic costs of incubation. There were no differences in the timing of brood desertion between experimental and control females in an experiment in which we lengthened or shortened the duration of incubation by one week. These results indicate that energetic costs do not explain offspring desertion by female Kentish plovers and that the needs of chicks for parental care rather than cumulative investment by females is what determines the timing of brood desertion. PMID:11413629

Novel statistical framework to identify differentially expressed genes allowing transcriptomic background differences.

PubMed

Ling, Zhi-Qiang; Wang, Yi; Mukaisho, Kenichi; Hattori, Takanori; Tatsuta, Takeshi; Ge, Ming-Hua; Jin, Li; Mao, Wei-Min; Sugihara, Hiroyuki

2010-06-01

Tests of differentially expressed genes (DEGs) from microarray experiments are based on the null hypothesis that genes that are irrelevant to the phenotype/stimulus are expressed equally in the target and control samples. However, this strict hypothesis is not always true, as there can be several transcriptomic background differences between target and control samples, including different cell/tissue types, different cell cycle stages and different biological donors. These differences lead to increased false positives, which have little biological/medical significance. In this article, we propose a statistical framework to identify DEGs between target and control samples from expression microarray data allowing transcriptomic background differences between these samples by introducing a modified null hypothesis that the gene expression background difference is normally distributed. We use an iterative procedure to perform robust estimation of the null hypothesis and identify DEGs as outliers. We evaluated our method using our own triplicate microarray experiment, followed by validations with reverse transcription-polymerase chain reaction (RT-PCR) and on the MicroArray Quality Control dataset. The evaluations suggest that our technique (i) results in less false positive and false negative results, as measured by the degree of agreement with RT-PCR of the same samples, (ii) can be applied to different microarray platforms and results in better reproducibility as measured by the degree of DEG identification concordance both intra- and inter-platforms and (iii) can be applied efficiently with only a few microarray replicates. Based on these evaluations, we propose that this method not only identifies more reliable and biologically/medically significant DEG, but also reduces the power-cost tradeoff problem in the microarray field. Source code and binaries freely available for download at http://comonca.org.cn/fdca/resources/softwares/deg.zip.

Why Does the Law of One Price Fail? An Experiment on Index Mutual Funds*

PubMed Central

Choi, James J.; Laibson, David; Madrian, Brigitte C.

2009-01-01

We conduct an experiment to evaluate why individuals invest in high-fee index funds. In our experiments, subjects allocate $10,000 across four S&P 500 index funds and are rewarded for their portfolio’s subsequent return. Subjects overwhelmingly fail to minimize fees. We can reject the hypothesis that subjects buy high-fee index funds because of bundled non-portfolio services. Search costs for fees matter, but even when we eliminate these costs, fees are not minimized. Instead, subjects place high weight on annualized returns since inception. Fees paid decrease with financial literacy. Interestingly, subjects who choose high-fee funds sense they are making a mistake. PMID:20495662

Guidelines for Initiating a Research Agenda: Topic Selection and Evidence of Impact.

PubMed

Delost, Maria E; Nadder, Teresa S

2014-01-01

The focus on scholarly productivity as an outcome measure for performance evaluations of personnel and/or units and benchmarking purposes is increasing in both the academic and clinical settings. This article presents avenues for identifying achievable research projects in both the academic and clinical settings. Factors for consideration when selecting a project include its significance or impact on the profession, feasibility for implementing the project, and ethical issues related to human subjects protection. A review of the literature is essential for identifying gaps in knowledge and for constructing the hypothesis or research question. Decisions concerning IRB submission, budget allocation, and collection of data must also be considered before implementation of the research design.

MeDIP-seq and nCpG analyses illuminate sexually dimorphic methylation of gonadal development genes with high historic methylation in turtle hatchlings with temperature-dependent sex determination.

PubMed

Radhakrishnan, Srihari; Literman, Robert; Mizoguchi, Beatriz; Valenzuela, Nicole

2017-01-01

DNA methylation alters gene expression but not DNA sequence and mediates some cases of phenotypic plasticity. Temperature-dependent sex determination (TSD) epitomizes phenotypic plasticity where environmental temperature drives embryonic sexual fate, as occurs commonly in turtles. Importantly, the temperature-specific transcription of two genes underlying gonadal differentiation is known to be induced by differential methylation in TSD fish, turtle and alligator. Yet, how extensive is the link between DNA methylation and TSD remains unclear. Here we test for broad differences in genome-wide DNA methylation between male and female hatchling gonads of the TSD painted turtle Chrysemys picta using methyl DNA immunoprecipitation sequencing, to identify differentially methylated candidates for future study. We also examine the genome-wide nCpG distribution (which affects DNA methylation) in painted turtles and test for historic methylation in genes regulating vertebrate gonadogenesis. Turtle global methylation was consistent with other vertebrates (57% of the genome, 78% of all CpG dinucleotides). Numerous genes predicted to regulate turtle gonadogenesis exhibited sex-specific methylation and were proximal to methylated repeats. nCpG distribution predicted actual turtle DNA methylation and was bimodal in gene promoters (as other vertebrates) and introns (unlike other vertebrates). Differentially methylated genes, including regulators of sexual development, had lower nCpG content indicative of higher historic methylation. Ours is the first evidence suggesting that sexually dimorphic DNA methylation is pervasive in turtle gonads (perhaps mediated by repeat methylation) and that it targets numerous regulators of gonadal development, consistent with the hypothesis that it may regulate thermosensitive transcription in TSD vertebrates. However, further research during embryogenesis will help test this hypothesis and the alternative that instead, most differential methylation observed in hatchlings is the by-product of sexual differentiation and not its cause.

Active and Passive Spatial Learning in Human Navigation: Acquisition of Graph Knowledge

ERIC Educational Resources Information Center

Chrastil, Elizabeth R.; Warren, William H.

2015-01-01

It is known that active exploration of a new environment leads to better spatial learning than does passive visual exposure. We ask whether specific components of active learning differentially contribute to particular forms of spatial knowledge--the "exploration-specific learning hypothesis". Previously, we found that idiothetic…

The Effects of Adolescent Activities on Delinquency: A Differential Involvement Approach

ERIC Educational Resources Information Center

Wong, Siu Kwong

2005-01-01

T. Hirschi's (1969, "Causes of Delinquency." University of California Press, Berkeley, CA) control theory proposes that involvement, as an element of the social bond, should reduce delinquency. But, research studies have found that the effect of involvement is rather weak. This study reformulates Hirschi's involvement hypothesis by…

Shyness and Emotion-Processing Skills in Preschoolers: A 6-Month Longitudinal Study

ERIC Educational Resources Information Center

Strand, Paul S.; Cerna, Sandra; Downs, Andrew

2008-01-01

The present study utilized a short-term longitudinal research design to examine the hypothesis that shyness in preschoolers is differentially related to different aspects of emotion processing. Using teacher reports of shyness and performance measures of emotion processing, including (1) facial emotion recognition, (2) non-facial emotion…

Toward Diagnostic and Phenotype Markers for Genetically Transmitted Speech Delay

ERIC Educational Resources Information Center

Shriberg, Lawrence D.; Lewis, Barbara A.; Tomblin, J. Bruce; McSweeny, Jane L.; Karlsson, Heather B.; Scheer, Alison R.

2005-01-01

Converging evidence supports the hypothesis that the most common subtype of childhood speech sound disorder (SSD) of currently unknown origin is genetically transmitted. We report the first findings toward a set of diagnostic markers to differentiate this proposed etiological subtype (provisionally termed "speech delay-genetic") from other…

The influence of past experience on wilderness choice

Treesearch

Alan E. Watson; Joseph W. Roggenbuck; Daniel R. Williams

1991-01-01

A study of Southern Appalachian backcountry hikers tested the hypothesis that recreationists with high experience levels would have greater differentiation of site attribute values when making recreation choices than would individuals with low experience. Contrary to cognitive development theory, a simulated laboratory choice study found that more experienced subjects...

Development of Category-based Induction and Semantic Knowledge

ERIC Educational Resources Information Center

Fisher, Anna V.; Godwin, Karrie E.; Matlen, Bryan J.; Unger, Layla

2015-01-01

Category-based induction is a hallmark of mature cognition; however, little is known about its origins. This study evaluated the hypothesis that category-based induction is related to semantic development. Computational studies suggest that early on there is little differentiation among concepts, but learning and development lead to increased…

Understanding Quantum Numbers in General Chemistry Textbooks

ERIC Educational Resources Information Center

Niaz, Mansoor; Fernandez, Ramon

2008-01-01

Quantum numbers and electron configurations form an important part of the general chemistry curriculum and textbooks. The objectives of this study are: (1) Elaboration of a framework based on the following aspects: (a) Origin of the quantum hypothesis, (b) Alternative interpretations of quantum mechanics, (c) Differentiation between an orbital and…

A Model of Differential Amygdala Activation in Psychopathy

ERIC Educational Resources Information Center

Moul, Caroline; Killcross, Simon; Dadds, Mark R.

2012-01-01

This article introduces a novel hypothesis regarding amygdala function in psychopathy. The first part of this article introduces the concept of psychopathy and describes the main cognitive and affective impairments demonstrated by this population; that is, a deficit in fear-recognition, lower conditioned fear responses and poor performance in…

Genetic and pharmacological analysis identifies a physiological role for the AHR in epidermal differentiation

PubMed Central

van den Bogaard, Ellen; Podolsky, Michael; Smits, Jos; Cui, Xiao; John, Christian; Gowda, Krishne; Desai, Dhimant; Amin, Shantu; Schalkwijk, Joost; Perdew, Gary H.

2015-01-01

Stimulation of the aryl hydrocarbon receptor (AHR) by xenobiotics is known to affect epidermal differentiation and skin barrier formation. The physiological role of endogenous AHR signaling in keratinocyte differentiation is not known. We used murine and human skin models to address the hypothesis that AHR activation is required for normal keratinocyte differentiation. Using transcriptome analysis of Ahr-/- and Ahr+/+ murine keratinocytes, we found significant enrichment of differentially expressed genes linked to epidermal differentiation. Primary Ahr-/- keratinocytes showed a significant reduction in terminal differentiation gene and protein expression, similar to Ahr+/+ keratinocytes treated with AHR antagonists GNF351 and CH223191, or the selective AHR modulator (SAhRM), SGA360. In vitro keratinocyte differentiation led to increased AHR levels and subsequent nuclear translocation, followed by induced CYP1A1 gene expression. Monolayer cultured primary human keratinocytes treated with AHR antagonists also showed an impaired terminal differentiation program. Inactivation of AHR activity during human skin equivalent development severely impaired epidermal stratification, terminal differentiation protein expression and stratum corneum formation. As disturbed epidermal differentiation is a main feature of many skin diseases, pharmacological agents targeting AHR signaling or future identification of endogenous keratinocyte-derived AHR ligands should be considered as potential new drugs in dermatology. PMID:25602157

Proportionate universalism in practice? A quasi-experimental study (GoWell) of a UK neighbourhood renewal programme's impact on health inequalities.

PubMed

Egan, Matt; Kearns, Ade; Katikireddi, Srinivasa V; Curl, Angela; Lawson, Kenny; Tannahill, Carol

2016-03-01

Recommendations to reduce health inequalities frequently emphasise improvements to socio-environmental determinants of health. Proponents of 'proportionate universalism' argue that such improvements should be allocated proportionally to population need. We tested whether city-wide investment in urban renewal in Glasgow (UK) was allocated to 'need' and whether this reduced health inequalities. We identified a longitudinal cohort (n = 1006) through data linkage across surveys conducted in 2006 and 2011 in 14 differentially disadvantaged neighbourhoods. Each neighbourhood received renewal investment during that time, allocated on the basis of housing need. We grouped neighbourhoods into those receiving 'higher', 'medium' or 'lower' levels of investment. We compared residents' self-reported physical and mental health between these three groups over time using the SF-12 version 2 instrument. Multiple linear regression adjusted for baseline gender, age, education, household structure, housing tenure, building type, country of birth and clustering. Areas receiving higher investment tended to be most disadvantaged in terms of baseline health, income deprivation and markers of social disadvantage. After five years, mean mental health scores improved in 'higher investment' areas relative to 'lower investment' areas (b = 4.26; 95% CI = 0.29, 8.22; P = 0.036). Similarly, mean physical health scores declined less in high investment compared to low investment areas (b = 3.86; 95% CI = 1.96, 5.76; P < 0.001). Relative improvements for medium investment (compared to lower investment) areas were not statistically significant. Findings suggest that investment in housing-led renewal was allocated according to population need and this led to modest reductions in area-based inequalities in health after five years. Study limitations include a risk of selection bias. This study demonstrates how non-health interventions can, and we believe should, be evaluated to better understand if and how health inequalities can be reduced through strategies of allocating investment in social determinants of health according to need. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

An Economic Analysis of Air-Conditioning Systems with Off-Peak Chilled-Water Storage.

DTIC Science & Technology

1981-09-01

law the Public Utility Regulatory Policies Act ( PURPA ) of 1978. "The objectives of this Act are: (1) to encourage users to conserve electricity and...rates for consumers C9:5]." The rate reforms proposed by PURPA are intended to reduce demand, change consumption patterns, and revise the allocation of...generally not time differentiated, off- peak users are subsidizing on-peak users [9:5-6J. The PURPA of 1978 rejected mandatory changes in electric utility

The effect of women's status and community on the gender differential in children's nutrition in India.

PubMed

Bose, Sunita

2011-09-01

This study uses the third National Family Health Survey (2005-06) in India to investigate whether differences in women's status, both at the individual and community levels, can explain the persistent gender differential in nutritional allocation among children. The results show that girls are less likely than boys to receive supplemental food and more likely to be malnourished. In general it appears that higher women's status within a community, as well as higher maternal status, have beneficial effects on a daughter's nutritional status. Further, the moderating effects of community appear to be more consistent and stronger than the individual-level characteristics. A positive relationship between the percentage of literate women in a community and the gender differential in malnutrition appears to be an exception to the general findings regarding the beneficial nature of women's status on a daughter's well-being, showing the need for more than just basic adult literacy drives in communities to overcome the problem of daughter neglect.

Multi Sensor Fusion Using Fitness Adaptive Differential Evolution

NASA Astrophysics Data System (ADS)

Giri, Ritwik; Ghosh, Arnob; Chowdhury, Aritra; Das, Swagatam

The rising popularity of multi-source, multi-sensor networks supports real-life applications calls for an efficient and intelligent approach to information fusion. Traditional optimization techniques often fail to meet the demands. The evolutionary approach provides a valuable alternative due to its inherent parallel nature and its ability to deal with difficult problems. We present a new evolutionary approach based on a modified version of Differential Evolution (DE), called Fitness Adaptive Differential Evolution (FiADE). FiADE treats sensors in the network as distributed intelligent agents with various degrees of autonomy. Existing approaches based on intelligent agents cannot completely answer the question of how their agents could coordinate their decisions in a complex environment. The proposed approach is formulated to produce good result for the problems that are high-dimensional, highly nonlinear, and random. The proposed approach gives better result in case of optimal allocation of sensors. The performance of the proposed approach is compared with an evolutionary algorithm coordination generalized particle model (C-GPM).

Modeling tree crown dynamics with 3D partial differential equations.

PubMed

Beyer, Robert; Letort, Véronique; Cournède, Paul-Henry

2014-01-01

We characterize a tree's spatial foliage distribution by the local leaf area density. Considering this spatially continuous variable allows to describe the spatiotemporal evolution of the tree crown by means of 3D partial differential equations. These offer a framework to rigorously take locally and adaptively acting effects into account, notably the growth toward light. Biomass production through photosynthesis and the allocation to foliage and wood are readily included in this model framework. The system of equations stands out due to its inherent dynamic property of self-organization and spontaneous adaptation, generating complex behavior from even only a few parameters. The density-based approach yields spatially structured tree crowns without relying on detailed geometry. We present the methodological fundamentals of such a modeling approach and discuss further prospects and applications.

Differential flank growth

NASA Astrophysics Data System (ADS)

Zieschang, H. E.; Sievers, A.

1994-08-01

With the mathematical basis for the precise analysis of developmental processes in plants, the patterns of growth in phototropic and gravitropic responses have become better understood. A detailed temporal and spatial quantification of a growth process is an important tool for evaluating hypotheses about the underlying physiological mechanisms. Studies of growth rates and curvature show that the original Cholodny-Went hypothesis cannot explain the complex growth patterns during tropic responses of shoots and roots. In addition, regulating factors other than the lateral redistribution of hormones must be taken into account. Electrophysiological studies on roots led to a modification of the Cholodny-Went hypothesis in that redistributions of bioelectrical activities are observed.

Hypothesis on how to measure electromagnetic hypersensitivity.

PubMed

Tuengler, Andreas; von Klitzing, Lebrecht

2013-09-01

Electromagnetic hypersensitivity (EHS) is an ill-defined term to describe the fact that people who experience health symptoms in the vicinity of electromagnetic fields (EMFs) regard them as causal for their complaints. Up to now most scientists assume a psychological cause for the suffering of electromagnetic hypersensitive individuals. This paper addresses reasons why most provocation studies could not find any association between EMF exposure and EHS and presents a hypothesis on diagnosis and differentiation of this condition. Simultaneous recordings of heart rate variability, microcirculation and electric skin potentials are used for classification of EHS. Thus, it could be possible to distinguish "genuine" electromagnetic hypersensitive individuals from those who suffer from other conditions.

Atherosclerosis is a vascular stem cell disease caused by insulin.

PubMed

Traunmüller, Friederike

2018-07-01

The present article proposes the hypothesis that when multipotent vascular stem cells are exposed to excessive insulin in a rhythmic pattern of sharply rising and falling concentrations, their differentiation is misdirected toward adipogenic and osteogenic cell lineages. This results in plaque-like accumulation of adipocytes with fat and cholesterol deposition from adipocyte debris, and osteogenic (progenitor) cells with a calcified matrix in advanced lesions. The ingrowth of capillaries and infiltration with macrophages, which upon uptake of lipids turn into foam cells, are unspecific pro-resolving reactions. Epidemiological, histopathological, pharmacological, and experimental evidence in favour of this hypothesis is summarised. Copyright © 2018. Published by Elsevier Ltd.

Transcriptomic insights into the genetic basis of mammalian limb diversity.

PubMed

Maier, Jennifer A; Rivas-Astroza, Marcelo; Deng, Jenny; Dowling, Anna; Oboikovitz, Paige; Cao, Xiaoyi; Behringer, Richard R; Cretekos, Chris J; Rasweiler, John J; Zhong, Sheng; Sears, Karen E

2017-03-23

From bat wings to whale flippers, limb diversification has been crucial to the evolutionary success of mammals. We performed the first transcriptome-wide study of limb development in multiple species to explore the hypothesis that mammalian limb diversification has proceeded through the differential expression of conserved shared genes, rather than by major changes to limb patterning. Specifically, we investigated the manner in which the expression of shared genes has evolved within and among mammalian species. We assembled and compared transcriptomes of bat, mouse, opossum, and pig fore- and hind limbs at the ridge, bud, and paddle stages of development. Results suggest that gene expression patterns exhibit larger variation among species during later than earlier stages of limb development, while within species results are more mixed. Consistent with the former, results also suggest that genes expressed at later developmental stages tend to have a younger evolutionary age than genes expressed at earlier stages. A suite of key limb-patterning genes was identified as being differentially expressed among the homologous limbs of all species. However, only a small subset of shared genes is differentially expressed in the fore- and hind limbs of all examined species. Similarly, a small subset of shared genes is differentially expressed within the fore- and hind limb of a single species and among the forelimbs of different species. Taken together, results of this study do not support the existence of a phylotypic period of limb development ending at chondrogenesis, but do support the hypothesis that the hierarchical nature of development translates into increasing variation among species as development progresses.

Prenatal programming of emotion regulation: neonatal reactivity as a differential susceptibility factor moderating the outcome of prenatal cortisol levels.

PubMed

Bolten, Margarete; Nast, Irina; Skrundz, Marta; Stadler, Christina; Hellhammer, Dirk H; Meinlschmidt, Gunther

2013-10-01

Hypothalamic-pituitary-adrenal (HPA) activation during pregnancy is linked to dysfunctional behavioral outcomes in the offspring. According to Belsky's differential susceptibility hypothesis, individuals vary regarding their developmental plasticity. Translating the differential susceptibility hypothesis to the field of fetal programming, we hypothesize that infants' temperament, as the constitutionally based reactivity to stimulation, moderates prenatal environmental effects on postnatal emotion regulation. Maternal HPA axis activity and stress-reactivity during pregnancy was estimated, by measuring cortisol concentrations in saliva, collected at 0, 30, 45 and 60 min after awakening and in blood, collected during a laboratory stress test (Trier Social Stress Test), respectively. Newborns reactivity to stimulation was evaluated between postnatal day 10 and 14 using the Neonatal Intensive Care Unit Network Neurobehavioral Scale. Infant's self-quieting-activities, as an indicator of emotion regulation, were evaluated at the age of six months during the still face paradigm. Maternal cortisol reactivity to stress during pregnancy was associated with infant's emotion regulation at the age of six months. Whereas cortisol levels after awakening in mid and late pregnancy were not associated with emotion regulation. Furthermore, regression analyses revealed that in interaction with neonatal reactivity, both, prenatal maternal HPA activity as well as prenatal maternal HPA reactivity to stress predicted emotion regulation. The findings indicate that newborns' reactivity to stimulation is moderating the association between prenatal exposure to maternal glucocorticoids and emotion regulation in infancy. Data suggests that temperamental characteristics of the newborn are a relevant differential susceptibility factor with regard to prenatal effects on emotion regulation. © 2013.

Differential relations between two dimensions of self-esteem and the Big Five?

PubMed

Ramsdal, Gro Hilde

2008-08-01

Recent research has suggested the possibility that self-esteem (SE) may be viewed as a two-dimensional concept consisting of: (a) self-liking, the subjective evaluation of oneself as a social being; and (b) self-competence, the internal conceptions of success and failure in performing tasks (Tafarodi & Swann, 1995). Establishing differential relations between these two dimensions of SE and an important psychological concept like the Big Five, would support the notion of two-dimensional SE. To test this hypothesis the self-liking/self-competence scale (SLCS) and the Big Five Inventory (BFI) were administered to 128 Norwegian college students. The results show a differential relationship between the two dimensions of SE and the personality dimensions of the BFI.

Phenotypic variation in metabolism and morphology correlating with animal swimming activity in the wild: relevance for the OCLTT (oxygen- and capacity-limitation of thermal tolerance), allocation and performance models

PubMed Central

Baktoft, Henrik; Jacobsen, Lene; Skov, Christian; Koed, Anders; Jepsen, Niels; Berg, Søren; Boel, Mikkel; Aarestrup, Kim; Svendsen, Jon C.

2016-01-01

Ongoing climate change is affecting animal physiology in many parts of the world. Using metabolism, the oxygen- and capacity-limitation of thermal tolerance (OCLTT) hypothesis provides a tool to predict the responses of ectothermic animals to variation in temperature, oxygen availability and pH in the aquatic environment. The hypothesis remains controversial, however, and has been questioned in several studies. A positive relationship between aerobic metabolic scope and animal activity would be consistent with the OCLTT but has rarely been tested. Moreover, the performance model and the allocation model predict positive and negative relationships, respectively, between standard metabolic rate and activity. Finally, animal activity could be affected by individual morphology because of covariation with cost of transport. Therefore, we hypothesized that individual variation in activity is correlated with variation in metabolism and morphology. To test this prediction, we captured 23 wild European perch (Perca fluviatilis) in a lake, tagged them with telemetry transmitters, measured standard and maximal metabolic rates, aerobic metabolic scope and fineness ratio and returned the fish to the lake to quantify individual in situ activity levels. Metabolic rates were measured using intermittent flow respirometry, whereas the activity assay involved high-resolution telemetry providing positions every 30 s over 12 days. We found no correlation between individual metabolic traits and activity, whereas individual fineness ratio correlated with activity. Independent of body length, and consistent with physics theory, slender fish maintained faster mean and maximal swimming speeds, but this variation did not result in a larger area (in square metres) explored per 24 h. Testing assumptions and predictions of recent conceptual models, our study indicates that individual metabolism is not a strong determinant of animal activity, in contrast to individual morphology, which is correlated with in situ activity patterns. PMID:27382465

Trust in food in the age of mad cow disease: a comparative study of consumers' evaluation of food safety in Belgium, Britain and Norway.

PubMed

Berg, Lisbet

2004-02-01

How do food scandals like dioxines in food in Belgium (summer 1999) and the detection of mad cow disease (BSE) in Britain affect consumers' confidence in food safety? In this paper, based on three thousand telephone interviews during the last quarter of 1999, consumers in Belgium and Britain are compared with consumers in Norway, where there has been no such serious food scandal in recent years. 'Trust' is a diffuse and complex concept to measure. In this article a consumer trust typology is developed and operationalised. Combining a trust-distrust dimension and a reflexivity dimension, it is possible to differentiate between four main consumer types, which are called 'sensible', 'sceptical', 'naive' and 'denying' consumers, respectively. Does the distribution of these consumer types vary in our selected countries? Are there gender differences across national borders? Four hypotheses of how consumers could respond to food scares are investigated: the Reflexivity hypothesis, the Risk-reducing hypothesis, the Complexity-reducing hypothesis and finally the Don't worry, be happy hypothesis.

Spatial and intertemporal arbitrage in the California natural gas transportation and storage network

NASA Astrophysics Data System (ADS)

Uria Martinez, Rocio

Intertemporal and spatial price differentials should provide the necessary signals to allocate a commodity efficiently inside a network. This dissertation investigates the extent to which decisions in the California natural gas transportation and storage system are taken with an eye on arbitrage opportunities. Daily data about flows into and out of storage facilities in California over 2002-2006 and daily spreads on the NYMEX futures market are used to investigate whether the injection profile is consistent with the "supply-of-storage" curve first observed by Working for wheat. Spatial price differentials between California and producing regions fluctuate throughout the year, even though spot prices at trading hubs across North America are highly correlated. In an analysis of "residual supply", gas volumes directed to California are examined for the influence of those fluctuations in locational differentials. Daily storage decisions in California do seem to be influenced by a daily price signal that combines the intertemporal spread and the locational basis between California and the Henry Hub, in addition to strong seasonal and weekly cycles. The timing and magnitude of the response differs across storage facilities depending on the regulatory requirements they face and the type of customers they serve. In contrast, deviations in spatial price differentials from the levels dictated by relative seasonality in California versus competing regions do not trigger significant reallocations of flows into California. Available data for estimation of both the supply-of-storage and residual-supply curves aggregate the behavior of many individuals whose motivations and attentiveness to prices vary. The resulting inventory and flow profiles differ from those that a social planner would choose to minimize operating costs throughout the network. Such optimal allocation is deduced from a quadratic programming model, calibrated to 2004-2005, that acknowledges relative seasonality in demand, trade-offs between transportation and storage costs, infrastructure configuration and regulatory requirements. A comparison of the simulated equilibrium with observed behavior identifies where the arbitrage opportunities lie. Moreover, scenario analysis of such as a LNG terminal or additional storage capacity in California reveals the considerable indirect network effects brought about by changes at any node or arc.

Progressive Chromatin Condensation and H3K9 Methylation Regulate the Differentiation of Embryonic and Hematopoietic Stem Cells

DOE PAGES

Ugarte, Fernando; Sousae, Rebekah; Cinquin, Bertrand; ...

2015-10-17

Epigenetic regulation serves as the basis for stem cell differentiation into distinct cell types, but it is unclear how global epigenetic changes are regulated during this process. Here, we tested the hypothesis that global chromatin organization affects the lineage potential of stem cells and that manipulation of chromatin dynamics influences stem cell function. Using nuclease sensitivity assays, we found a progressive decrease in chromatin digestion among pluripotent embryonic stem cells (ESCs), multipotent hematopoietic stem cells (HSCs), and mature hematopoietic cells. Quantitative high-resolution microscopy revealed that ESCs contain significantly more euchromatin than HSCs, with a further reduction in mature cells. Increasedmore » cellular maturation also led to heterochromatin localization to the nuclear periphery. Functionally, prevention of heterochromatin formation by inhibition of the histone methyltransferase G9A resulted in delayed HSC differentiation. Lastly, our results demonstrate global chromatin rearrangements during stem cell differentiation and that heterochromatin formation by H3K9 methylation regulates HSC differentiation.« less

Progressive Chromatin Condensation and H3K9 Methylation Regulate the Differentiation of Embryonic and Hematopoietic Stem Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ugarte, Fernando; Sousae, Rebekah; Cinquin, Bertrand

Epigenetic regulation serves as the basis for stem cell differentiation into distinct cell types, but it is unclear how global epigenetic changes are regulated during this process. Here, we tested the hypothesis that global chromatin organization affects the lineage potential of stem cells and that manipulation of chromatin dynamics influences stem cell function. Using nuclease sensitivity assays, we found a progressive decrease in chromatin digestion among pluripotent embryonic stem cells (ESCs), multipotent hematopoietic stem cells (HSCs), and mature hematopoietic cells. Quantitative high-resolution microscopy revealed that ESCs contain significantly more euchromatin than HSCs, with a further reduction in mature cells. Increasedmore » cellular maturation also led to heterochromatin localization to the nuclear periphery. Functionally, prevention of heterochromatin formation by inhibition of the histone methyltransferase G9A resulted in delayed HSC differentiation. Lastly, our results demonstrate global chromatin rearrangements during stem cell differentiation and that heterochromatin formation by H3K9 methylation regulates HSC differentiation.« less

Discovery of a stem-like multipotent cell fate.

PubMed

Paffhausen, Emily S; Alowais, Yasir; Chao, Cara W; Callihan, Evan C; Creswell, Karen; Bracht, John R

2018-01-01

Adipose derived stem cells (ASCs) can be obtained from lipoaspirates and induced in vitro to differentiate into bone, cartilage, and fat. Using this powerful model system we show that after in vitro adipose differentiation a population of cells retain stem-like qualities including multipotency. They are lipid (-), retain the ability to propagate, express two known stem cell markers, and maintain the capacity for trilineage differentiation into chondrocytes, adipocytes, and osteoblasts. However, these cells are not traditional stem cells because gene expression analysis showed an overall expression profile similar to that of adipocytes. In addition to broadening our understanding of cellular multipotency, our work may be particularly relevant to obesity-associated metabolic disorders. The adipose expandability hypothesis proposes that inability to differentiate new adipocytes is a primary cause of metabolic syndrome in obesity, including diabetes and cardiovascular disease. Here we have defined a differentiation-resistant stem-like multipotent cell population that may be involved in regulation of adipose expandability in vivo and may therefore play key roles in the comorbidities of obesity.

[The German DRG system and its effect on imaging quality in ENT, and head and neck surgery].

PubMed

Franz, D; Roeder, N; Hörmann, K; Alberty, J

2006-04-01

The new G-DRG system for 2006 was published in September 2005. This article presents, analyses, and comments essential changes in the G-DRG system for 2006 and their consequences for ENT-Medicine. The complexity of the G-DRG system has increased significantly. In 2006, the case allocation will be more differentiated for common surgical procedures on the middle ear, nose, paranasal sinuses, salivary glands, and for head and neck cancer. Furthermore, the patient's age and the clinical and complexity level (PCCL) will be of increased relevance in selected case constellations. However, diagnostic endoscopies with rigid instruments will still not be regarded as OR procedures. Essential adjustments proposed by the German Association for ENT Medicine (DGHNOKHC) and the ENT Medical Professional Association (HNO-Berufsverband) have been made, and the quality of case allocation of ENT-patients within the G-DRG system improved. Nevertheless, further adjustments to the G-DRG system are necessary.

Task Complexity, the Cognition Hypothesis, and Interaction in CMC and FTF Environments

ERIC Educational Resources Information Center

Baralt, Melissa Lorrain

2010-01-01

The construct of cognitive complexity has played an increasingly important role in studies on task design, which aim to explore how increases in the cognitive complexity of tasks differentially mediate interaction and learning outcomes (Kim, 2009; Gilabert, Baron, & Llanes, 2009; Kim & Tracy-Ventura, forthcoming; Nuevo, 2006; Revesz, 2009,…

A Study of Family Support, Friendship, and Psychological Well-Being among Older Women in Hong Kong

ERIC Educational Resources Information Center

Siu, Oi-Ling; Phillips, David R.

2002-01-01

The "dual-channel" hypothesis (Lawton, 1996), which suggests the dual-antecedent pattern for positive and negative aspects of psychological well-being, was tested by examining the differential relationships between objective and subjective measures of family support (family contact, family quality, perceived importance of family) and…

How Temperament and Personality Contribute to the Maladjustment of Children with Autism

ERIC Educational Resources Information Center

De Pauw, Sarah S. W.; Mervielde, Ivan; Van Leeuwen, Karla G.; De Clercq, Barbara J.

2011-01-01

To test the spectrum hypothesis--postulating that clinical and non-clinical samples are primarily differentiated by mean-level differences--, this study evaluates differences in parent-rated temperament, personality and maladjustment among a low-symptom (N = 81), a high-symptom (N = 94) ASD-group, and a comparison group (N = 500). These classic…

Comparative inflammatory effects of differential particulate matter species in an OVA-sensitization and challenge model

EPA Science Inventory

Exposure to respirable ambient particulate matter (APM) provokes allergic immunity that may also occur on exposure to environmental diesel exhaust particles (eDEP) or emission source DEP (cDEP). Our hypothesis tested whether APM, eDEP or cDEP provide immune adjuvancy in an antige...

Integrating Articulatory Constraints into Models of Second Language Phonological Acquisition

ERIC Educational Resources Information Center

Colantoni, Laura; Steele, Jeffrey

2008-01-01

Models such as Eckman's markedness differential hypothesis, Flege's speech learning model, and Brown's feature-based theory of perception seek to explain and predict the relative difficulty second language (L2) learners face when acquiring new or similar sounds. In this paper, we test their predictive adequacy as concerns native English speakers'…

The Allusion of the Gene: Misunderstandings of the Concepts Heredity and Gene

ERIC Educational Resources Information Center

Falk, Raphael

2014-01-01

Life sciences became Biology, a formal scientific discipline, at the turn of the nineteenth century, when it adopted the methods of reductive physics and chemistry. Mendel's hypothesis of inheritance of discrete factors further introduced a quantitative reductionist dimension into biology. In 1910 Johannsen differentiated between the…

Using and Evaluating Differential Modeling in Intelligent Tutoring and Apprentice Learning Systems.

DTIC Science & Technology

1987-01-01

medical diagnosis (Buchanan and Shortliffe, 1984); student hypothesis errors are discovered in the process of conducting a Socratic dialogue. Recent... Jose Mestre Pit-sb r h, PA 15213 Urbana, IL 61801 Department of Physics D- %iDHasbrouck Laboratory A; Jilr ieLaKin Dr. Don Lyon University of

Landscape and regional context differentially affect nest parasitism and nest predation for Wood Thrush in central Virginia, USA

EPA Science Inventory

Many empirical studies have shown that forest-breeding songbirds, and neotropical migrants in particular, are found in lower abundance in small patches of forest in the Eastern United States compared to similar, but larger patches in the same region. A common hypothesis for the ...

Being in the Know: Early Adolescents' Knowledge of Who Bullies Whom

ERIC Educational Resources Information Center

Hanish, Laura D.; Andrews, Naomi C. Z.; Kornienko, Olga; Santos, Carlos E.; Rodkin, Philip C.; Granger, Kristen L.

2016-01-01

We tested the hypothesis that early adolescents' (N = 951) knowledge of who bullies whom is differentially distributed across peers. Knowledge of bullying was assessed by asking middle school students to nominate grademates who bullied or were bullied using physical or relational means. We hypothesized that peers who were closer to bullies and…

Stay on or Drop Out? The Role of Identities in Continued Participation at Technical College in Australia

ERIC Educational Resources Information Center

Fisher, Laurel J.

2014-01-01

Identities extend standard models that explain student motivations to complete courses at technical college. A differential hypothesis was that profiles of identities (individuality, belonging and place) explain the self-concepts and task values that contribute to participation, considering demographic factors (age, gender, location, paid work).…

Identification of Parent-Child Interaction Characteristics of High and Low Achieving Elementary Students.

ERIC Educational Resources Information Center

Portes, Pedro R.; And Others

The present study was designed to identify parent-child interaction patterns that might differentiate bright from below average elementary students in order to test the hypothesis that environmental processes related to regulation of executive processes influence both children's learning and developmental level. Thirty-two mother-child dyads (16…

Affecting Girls' Activity and Job Interests through Play: The Moderating Roles of Personal Gender Salience and Game Characteristics

ERIC Educational Resources Information Center

Coyle, Emily F.; Liben, Lynn S.

2016-01-01

Gender schema theory (GST) posits that children approach opportunities perceived as gender appropriate, avoiding those deemed gender inappropriate, in turn affecting gender-differentiated career trajectories. To test the hypothesis that children's gender salience filters (GSF--tendency to attend to gender) moderate these processes, 62 preschool…

Multiple Goals Perspective in Adolescent Students with Learning Difficulties

ERIC Educational Resources Information Center

Nunez, Jose Carlos; Gonzalez-Pienda, Julio Antonio; Rodriguez, Celestino; Valle, Antonio; Gonzalez-Cabanach, Ramon; Rosario, Pedro

2011-01-01

In the present work, the hypothesis of the existence of diverse motivational profiles in students with learning difficulties (LD) and the differential implications for intervention in the classroom are analyzed. Various assessment scales (academic goals, self-concept, and causal attributions) were administered to a sample of 259 students with LD,…

Differentiating Processes of Control and Understanding in the Early Development of Emotion and Cognition

ERIC Educational Resources Information Center

Blankson, A. Nayena; O'Brien, Marion; Leerkes, Esther M.; Marcovitch, Stuart; Calkins, Susan D.

2012-01-01

In this study, we examined the hypothesis that preschoolers' performance on emotion and cognitive tasks is organized into discrete processes of control and understanding within the domains of emotion and cognition. Additionally, we examined the relations among component processes using mother report, behavioral observation, and physiological…

Immunotoxicological Analysis of the Immune Adjuvant Effects of Source Specific Diesel and Environmental Ambient Particulate Matter in a Murine Sensitization And Challenge Model.

EPA Science Inventory

Rationale: Acute exposure to ambient particulate matter (APM) provokes oxidative and inflammatory lung activation in vivo. Here, we test the hypothesis that environmental diesel exhaust particles (eDEP), emission source-specific DEP (cDEP) and APM differentially provoke an allerg...

Sex Role Learning: A Test of the Selective Attention Hypothesis.

ERIC Educational Resources Information Center

Bryan, Janice Westlund; Luria, Zella

This paper reports three studies designed to determine whether children show selective attention and/or differential memory to slide pictures of same-sex vs. opposite-sex models and activities. Attention was measured using a feedback EEG procedure, which measured the presence or absence of alpha rhythms in the subjects' brains during presentation…

Personality Traits, Vocational Interests, and Career Exploration: A Cross-Cultural Comparison between American and Hong Kong Students

ERIC Educational Resources Information Center

Fan, Weiqiao; Cheung, Fanny M.; Leong, Frederick T. L.; Cheung, Shu Fai

2012-01-01

This study compared the pattern of relationships among personality, vocational interests, and career exploration within an integrated framework between 369 American and 392 Hong Kong university students. The first hypothesis predicted differential contributions of the universal and indigenous personality dimensions based on the Cross-cultural…

Selectivity in L1 Attrition: Differential Object Marking in Spanish Near-Native Speakers of English

ERIC Educational Resources Information Center

Chamorro, Gloria; Sturt, Patrick; Sorace, Antonella

2016-01-01

Previous research has shown L1 attrition to be restricted to structures at the interfaces between syntax and pragmatics, but not to occur with syntactic properties that do not involve such interfaces ("Interface Hypothesis", Sorace and Filiaci in "Anaphora resolution in near-native speakers of Italian." "Second Lang…

Differentiation at Higher Levels of Cognitive Ability: Evidence from the United States

ERIC Educational Resources Information Center

Kane, Harrison D.; Oakland, Thomas D.; Brand, Christopher R.

2006-01-01

Most psychologists and educators assume that intelligence is a linear construct, meaning that smart people simply have more intelligence than their less gifted peers. Likewise, individuals with mental retardation are thought to have less intelligence. In contrast to this widely accepted belief, the authors posed an alternative hypothesis--that…

Attachment and Depression Differentially Influence Nicotine Dependence among Male and Female Undergraduates: A Preliminary Study.

ERIC Educational Resources Information Center

McChargue, Dennis E.; Cohen, Lee M.; Cook, Jessica W.

2004-01-01

The authors surveyed a convenience sample of 208 undergraduate students who reported that they smoked cigarettes. The primary hypothesis they tested was whether gender predicted nicotine dependence. They further tested whether depression and attachment would mediate or moderate this relationship. Hierarchical regression analyses with social…

Donor cell differentiation, reprogramming, and cloning efficiency: elusive or illusive correlation?

PubMed

Oback, B; Wells, D N

2007-05-01

Compared to other assisted reproductive technologies, mammalian nuclear transfer (NT) cloning is inefficient in generating viable offspring. It has been postulated that nuclear reprogramming and cloning efficiency can be increased by choosing less differentiated cell types as nuclear donors. This hypothesis is mainly supported by comparative mouse cloning experiments using early blastomeres, embryonic stem (ES) cells, and terminally differentiated somatic donor cells. We have re-evaluated these comparisons, taking into account different NT procedures, the use of donor cells from different genetic backgrounds, sex, cell cycle stages, and the lack of robust statistical significance when post-blastocyst development is compared. We argue that while the reprogrammability of early blastomeres appears to be much higher than that of somatic cells, it has so far not been conclusively determined whether differentiation status affects cloning efficiency within somatic donor cell lineages. Copyright (c) 2006 Wiley-Liss, Inc.

ϒ Spike-Field Coherence in a Population of Olfactory Bulb Neurons Differentiates between Odors Irrespective of Associated Outcome

PubMed Central

Li, Anan; Gire, David H.

2015-01-01

Studies in different sensory systems indicate that short spike patterns within a spike train that carry items of sensory information can be extracted from the overall train by using field potential oscillations as a reference (Kayser et al., 2012; Panzeri et al., 2014). Here we test the hypothesis that the local field potential (LFP) provides the temporal reference frame needed to differentiate between odors regardless of associated outcome. Experiments were performed in the olfactory system of the mouse (Mus musculus) where the mitral/tufted (M/T) cell spike rate develops differential responses to rewarded and unrewarded odors as the animal learns to associate one of the odors with a reward in a go–no go behavioral task. We found that coherence of spiking in M/T cells with the ϒ LFP (65 to 95 Hz) differentiates between odors regardless of the associated behavioral outcome of odor presentation. PMID:25855190

Apoptosis in the areas of squamous differentiation of irritated seborrheic keratosis.

PubMed

Pesce, C; Scalora, S

2000-03-01

Seborrheic keratosis (SK) consists of a localized proliferation of basaloid keratinocytes, often accompanied by hyperkeratosis and hyperpigmentation. In irritated SK, these features are associated with areas of squamous differentiation with larger keratinocytes and squamous cell eddies. This work is concerned with the evaluation of apoptosis, as demonstrated by the TUNEL method, in the different varieties of SK. Apoptosis was highly expressed in the areas of squamous differentiation of irritated SK, but only mildly increased in the other varieties of SK. These data support the hypothesis that apoptosis has a role in the squamous differentiation of irritated SK. In consideration also of previous data showing that irritated SK is associated with downregulation of EGF-R expression and 125I-EGF binding, we postulate that the morphologic features of irritated SK could correspond to an involution phase of the disease, characterized by altered cell balance with inadequate cell renewal and increased cell loss.

Role of inflammation in the aging bones.

PubMed

Abdelmagid, Samir M; Barbe, Mary F; Safadi, Fayez F

2015-02-15

Chronic inflammation in aging is characterized by increased inflammatory cytokines, bone loss, decreased adaptation, and defective tissue repair in response to injury. Aging leads to inherent changes in mesenchymal stem cell (MSC) differentiation, resulting in impaired osteoblastogenesis. Also, the pro-inflammatory cytokines increase with aging, leading to enhanced myelopoiesis and osteoclastogenesis. Bone marrow macrophages (BMMs) play pivotal roles in osteoblast differentiation, the maintenance of hematopoietic stem cells (HSCs), and subsequent bone repair. However, during aging, little is known about the role of macrophages in the differentiation and function of MSC and HSC. Aged mammals have higher circulating pro-inflammatory cytokines than young adults, supporting the hypothesis of increased inflammation with aging. This review will aid in the understanding of the potential role(s) of pro-inflammatory (M1) and anti-inflammatory (M2) macrophages in differentiation and function of osteoblasts and osteoclasts in relation to aging. Copyright © 2014 Elsevier Inc. All rights reserved.

AhR-mediated gene expression in the developing mouse telencephalon.

PubMed

Gohlke, Julia M; Stockton, Pat S; Sieber, Stella; Foley, Julie; Portier, Christopher J

2009-11-01

We hypothesize that TCDD-induced developmental neurotoxicity is modulated through an AhR-dependent interaction with key regulatory neuronal differentiation pathways during telencephalon development. To test this hypothesis we examined global gene expression in both dorsal and ventral telencephalon tissues in E13.5 AhR-/- and wildtype mice exposed to TCDD or vehicle. Consistent with previous biochemical, pathological and behavioral studies, our results suggest TCDD initiated changes in gene expression in the developing telencephalon are primarily AhR-dependent, as no statistically significant gene expression changes are evident after TCDD exposure in AhR-/- mice. Based on a gene regulatory network for neuronal specification in the developing telencephalon, the present analysis suggests differentiation of GABAergic neurons in the ventral telencephalon is compromised in TCDD exposed and AhR-/- mice. In addition, our analysis suggests Sox11 may be directly regulated by AhR based on gene expression and comparative genomics analyses. In conclusion, this analysis supports the hypothesis that AhR has a specific role in the normal development of the telencephalon and provides a mechanistic framework for neurodevelopmental toxicity of chemicals that perturb AhR signaling.

Endocrine and metabolic aspects of the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorski, J.R.

1988-01-01

Toxic responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were characterized in male Sprague-Dawley rats in order to elucidate the mechanism of acute toxicity of this potent halogenated hydrocarbon. Studies in TCDD-treated, pair-fed control and ad libitum-fed control rates, as well as in thyroidectomized, adrenalectomized and hypophysectomized, revealed differential hormonal, toxicologic and histophathologic responses suggesting that these manifestations of TCDD exposure are the results of an insult to intermediary metabolism. Tissue specific alterations in de novo fatty acid synthesis were directly related to differential changes observed in thyroid hormone homeostasis. The increased hepatic de novo fatty acid synthesis provided a likely mechanism for themore » documented fact that TCDD-treated rats lose more body weight than corresponding pair-fed controls because de novo fatty acid synthesis represents an energy inefficient metabolic process. Experiments in adrenalectomized and hypophysectomized rats led to the hypothesis that severe hypoglycemia due to inhibition of gluconeogenesis is the cause of TCDD-induced death. A subsequent characterization of gluconeogenesis in TCDD-treated rats confirmed this hypothesis.« less

Use of electron microscopy to classify canine perivascular wall tumors.

PubMed

Palmieri, C; Avallone, G; Cimini, M; Roccabianca, P; Stefanello, D; Della Salda, L

2013-03-01

The histologic classification of canine perivascular wall tumors (PWTs) is controversial. Many PWTs are still classified as hemangiopericytomas (HEPs), and the distinction from peripheral nerve sheath tumors (PNSTs) is still under debate. A recent histologic classification of canine soft tissue sarcomas included most histologic types of PWT but omitted those that were termed undifferentiated. Twelve cases of undifferentiated canine PWTs were evaluated by transmission electron microscopy. The ultrastructural findings supported a perivascular wall origin for all cases with 4 categories of differentiation: myopericytic (n = 4), myofibroblastic (n = 1), fibroblastic (n = 2), and undifferentiated (n = 5). A PNST was considered unlikely in each case based on immunohistochemical expression of desmin and/or the lack of typical ultrastructural features, such as basal lamina. Electron microscopy was pivotal for the subclassification of canine PWTs, and the results support the hypothesis that canine PWTs represent a continuum paralleling the phenotypic plasticity of vascular mural cells. The hypothesis that a subgroup of PWTs could arise from a pluripotent mesenchymal perivascular wall cell was also considered and may explain the diverse differentiation of canine PWTs.

A study of the differential effects of Tomm's questioning styles on therapeutic alliance.

PubMed

Ryan, D; Carr, A

2001-01-01

To replicate and extend Dozier's (1992) test of Tomm's hypothesis about the differential effects of questioning styles on therapeutic alliance, an analogue study was conducted. Twenty-eight family triads, each including a son and his parents, viewed four videotaped, simulated family therapy scenarios in which Tomm's four questioning styles were separately portrayed. Participants were asked to identify with the client whose role corresponded to theirs (that is, father, mother, or son) and, on the basis of this, to rate the client's alliance with the therapist. They were also asked to rate the overall alliance between the family and the therapist. Finally, having viewed all four scenarios, they were invited to rate comparatively the quality of the therapeutic alliance across the four questioning styles. Compared with strategic and lineal questioning styles, circular and reflexive questions led to higher ratings of therapeutic alliance on all three measures. The results of this study support Tomm's hypothesis that questioning styles based on circular assumptions lead to a better therapeutic alliance at an individual and systemic level than do questions based on lineal assumptions.

Differential foraging success across a light level spectrum explains the maintenance and spatial structure of colour morphs in a polymorphic bird.

PubMed

Tate, Gareth J; Bishop, Jacqueline M; Amar, Arjun

2016-06-01

Detectability of different colour morphs under varying light conditions has been proposed as an important driver in the maintenance of colour polymorphism via disruptive selection. To date, no studies have tested whether different morphs have selective advantages under differing light conditions. We tested this hypothesis in the black sparrowhawk, a polymorphic raptor exhibiting a discrete white and dark morph, and found that prey provisioning rates differ between the morphs depending on light condition. Dark morphs delivered more prey in lower light conditions, while white morphs provided more prey in brighter conditions. We found support for the role of breeding season light level in explaining the clinal pattern of variation in morph ratio across the species range throughout South Africa. Our results provide the first empirical evidence supporting the hypothesis that polymorphism in a species, and the spatial structuring of morphs across its distribution, may be driven by differential selective advantage via improved crypsis, under varying light conditions. © 2016 John Wiley & Sons Ltd/CNRS.

Evolutionary consequences of microhabitat: population-genetic structuring in kelp- vs. rock-associated chitons.

PubMed

Nikula, R; Spencer, H G; Waters, J M

2011-12-01

Rafting has long been invoked as a key marine dispersal mechanism, but biologists have thus far produced little genetic evidence to support this hypothesis. We hypothesize that coastal species associated with buoyant seaweeds should experience enhanced population connectivity owing to rafting. In particular, invertebrates strongly associated with the buoyant bull-kelp Durvillaea antarctica might be expected to have lower levels of population-genetic differentiation than taxa mainly exploiting nonbuoyant substrates. We undertook a comparative genetic study of two codistributed, congeneric chiton species, assessing population connectivity at scales of 61-516 km, using ≥ 186 polymorphic AFLP loci per species. Consistent with predictions, population-genetic differentiation was weaker in the kelp-associated Sypharochiton sinclairi than in the rock-associated S. pelliserpentis. Additionally, while we found a significant positive correlation between genetic and oceanographic distances in both chiton species, the correlation was stronger in S. pelliserpentis (R(2) = 0.28) than in S. sinclairi (R(2) = 0.18). These data support the hypothesis that epifaunal taxa can experience enhanced population-genetic connectivity as a result of their rafting ability. © 2011 Blackwell Publishing Ltd.

Brain stimulation over Broca’s area differentially modulates naming skills in neurotypical adults and individuals with Asperger’s syndrome

PubMed Central

Fecteau, Shirley; Agosta, Sara; Oberman, Lindsay; Pascual-Leone, Alvaro

2012-01-01

In the present study we tested the hypothesis that, in subjects with Asperger’s syndrome (ASP), the dynamics of language-related regions might be abnormal, so that repetitive transcranial magnetic stimulation (rTMS) over Broca’s area leads to differential behavioral effects as seen in neurotypical controls. We conducted a five-stimulation-site, double-blind, multiple crossover, pseudo-randomized, sham-controlled study in 10 individuals with ASP and 10 age- and gender-matched healthy subjects. Object naming was assessed before and after low-frequency rTMS of the left pars opercularis, left pars triangularis, right pars opercularis and right pars triangularis, and sham stimulation, as guided stereotaxically by each individual’s brain magnetic resonance imaging. In ASP participants, naming improved after rTMS of the left pars triangularis as compared with sham stimulation, whereas rTMS of the adjacent left opercularis lengthened naming latency. In healthy subjects, stimulation of parts of Broca’s area did not lead to significant changes in naming skills, consistent with published data. Overall, these findings support our hypothesis of abnormal language neural network dynamics in individuals with ASP. From a methodological point of view, this work illustrates the use of rTMS to study the dynamics of brain–behavior relations by revealing the differential behavioral impact of non-invasive brain stimulation in a neuropsychiatric disorder. PMID:21676037

The gender wealth gap:structural and material constraints and implications for later life.

PubMed

Denton, Margaret; Boos, Linda

2007-01-01

Wealth is an important measure of economic well-being, because while income captures the current state of inequality, wealth has the potential for examining accumulated and historically structured inequality. This presentation documents the extent of gender inequality in wealth for Canadian women and men aged 45 and older. The analysis uses data from the 1999 Canadian Survey of Financial Security, a large nationally representative survey of household wealth in Canada. Wealth is measured by total net worth as measured by total assets minus debt. We test two general hypotheses to account for gender differences in wealth. The differential exposure hypothesis suggests that women report less wealth accumulation because of their reduced access to the material and social conditions of life that foster economic security. The differential vulnerability hypothesis suggests that women report lower levels of wealth because they receive differential returns to material and social conditions of their lives. Support is found for both hypotheses. Much of the gender differences in wealth can be explained by the gendering of work and family roles that restricts women's ability to build up assets over the life course. But beyond this, there are significant gender interaction effects that indicate that women are further penalized by their returns to participation in family life, their health and where they live. When women do work, net of other factors, they are better able to accumulate wealth than their male counterparts.

Why classroom climate matters for children high in anxious solitude: A study of differential susceptibility.

PubMed

Hughes, Kathleen; Coplan, Robert J

2018-03-01

The goal of the current study was to examine the complex links among anxious solitude, classroom climate, engagement, achievement, and gender. In particular, drawing upon the differential susceptibility hypothesis (Belsky, 1997), we investigated if children high in anxious solitude were particularly sensitive and responsive to the classroom environment. Participants were N = 712 children in Grade 3, drawn from the National Institute of Child and Human Development (NICHD) Study of Early Child Care and Youth Development data set. Classroom climate and engagement were assessed using the Classroom Observation Scale (NICHD, 1998). Teachers completed the Teacher Report Form (Achenbach, 1991) as a measure of anxious solitude and the Academic Rating Scale (NICHD, 2010) as a measure of achievement. Hypothesized associations among variables were tested by way of a moderated-mediation model. Among the results, engagement was found to mediate the relation between classroom climate and achievement. In addition, anxious solitude and gender were found to moderate the relation between classroom climate and engagement. Support for the differential susceptibility hypothesis was found, suggesting that children high in anxious solitude may be more reactive (both positively and negatively) to elements of the classroom environment. In addition, gender differences were observed, indicating that boys may be more responsive to the classroom environment as compared with girls. Implications for future research and educational policies are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Inference for High-dimensional Differential Correlation Matrices *

PubMed Central

Cai, T. Tony; Zhang, Anru

2015-01-01

Motivated by differential co-expression analysis in genomics, we consider in this paper estimation and testing of high-dimensional differential correlation matrices. An adaptive thresholding procedure is introduced and theoretical guarantees are given. Minimax rate of convergence is established and the proposed estimator is shown to be adaptively rate-optimal over collections of paired correlation matrices with approximately sparse differences. Simulation results show that the procedure significantly outperforms two other natural methods that are based on separate estimation of the individual correlation matrices. The procedure is also illustrated through an analysis of a breast cancer dataset, which provides evidence at the gene co-expression level that several genes, of which a subset has been previously verified, are associated with the breast cancer. Hypothesis testing on the differential correlation matrices is also considered. A test, which is particularly well suited for testing against sparse alternatives, is introduced. In addition, other related problems, including estimation of a single sparse correlation matrix, estimation of the differential covariance matrices, and estimation of the differential cross-correlation matrices, are also discussed. PMID:26500380

Differential Susceptibility in Spillover Between Interparental Conflict and Maternal Parenting Practices: Evidence for OXTR and 5-HTT Genes

PubMed Central

Sturge-Apple, Melissa L.; Cicchetti, Dante; Davies, Patrick T.; Suor, Jennifer H.

2012-01-01

Guided by the affective spillover hypothesis and the differential susceptibility to environmental influence frameworks, the present study examined how associations between interparental conflict and mothers’ parenting practices were moderated by serotonin transporter (5-HTT) and oxytocin receptor (OXTR) genes. A sample of 201 mothers and their two-year old child participated in a laboratory-based research assessment. Results supported differential susceptibility hypotheses within spillover frameworks. With respect to OXTR rs53576, mothers with the GG genotype showed greater differential maternal sensitivity across varying levels of interparental conflict. Mothers with one or two copies of the 5-HTTLPR S allele demonstrated differential susceptibility for both sensitive and harsh/punitive caregiving behaviors. Finally, analyses examined whether maternal depressive symptoms and emotional closeness to their child mediated the moderating effects. Findings suggest that maternal emotional closeness with their child indirectly linked OXTR with maternal sensitivity. The results highlight how molecular genetics may explain heterogeneity in spillover models with differential implications for specific parenting behaviors. Implications for clinicians and therapists working with maritally distressed parents are discussed. PMID:22563705

Optimal Power Allocation for Downstream xDSL With Per-Modem Total Power Constraints: Broadcast Channel Optimal Spectrum Balancing (BC-OSB)

NASA Astrophysics Data System (ADS)

Le Nir, Vincent; Moonen, Marc; Verlinden, Jan; Guenach, Mamoun

2009-02-01

Recently, the duality between Multiple Input Multiple Output (MIMO) Multiple Access Channels (MAC) and MIMO Broadcast Channels (BC) has been established under a total power constraint. The same set of rates for MAC can be achieved in BC exploiting the MAC-BC duality formulas while preserving the total power constraint. In this paper, we describe the BC optimal power allo- cation applying this duality in a downstream x-Digital Subscriber Lines (xDSL) context under a total power constraint for all modems over all tones. Then, a new algorithm called BC-Optimal Spectrum Balancing (BC-OSB) is devised for a more realistic power allocation under per-modem total power constraints. The capacity region of the primal BC problem under per-modem total power constraints is found by the dual optimization problem for the BC under per-modem total power constraints which can be rewritten as a dual optimization problem in the MAC by means of a precoder matrix based on the Lagrange multipliers. We show that the duality gap between the two problems is zero. The multi-user power allocation problem has been solved for interference channels and MAC using the OSB algorithm. In this paper we solve the problem of multi-user power allocation for the BC case using the OSB algorithm as well and we derive a computational efficient algorithm that will be referred to as BC-OSB. Simulation results are provided for two VDSL2 scenarios: the first one with Differential-Mode (DM) transmission only and the second one with both DM and Phantom- Mode (PM) transmissions.

Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

PubMed

Clark, Rebecca M; Zera, Anthony J; Behmer, Spencer T

2015-01-15

Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off. © 2015. Published by The Company of Biologists Ltd.

The development of children's knowledge of attention and resource allocation in single and dual tasks.

PubMed

Dossett, D; Burns, B

2000-06-01

Developmental changes in kindergarten, 1st-, and 4th-grade children's knowledge about the variables that affect attention sharing and resource allocation were examined. Findings from the 2 experiments showed that kindergartners understood that person and strategy variables affect performance in attention-sharing tasks. However, knowledge of how task variables affect performance was not evident to them and was inconsistent for 1st and 4th graders. Children's knowledge about resource allocation revealed a different pattern and varied according to the dissimilarity of task demands in the attention-sharing task. In Experiment 1, in which the dual attention tasks were similar (i.e., visual detection), kindergarten and 1st-grade children did not differentiate performance in single and dual tasks. Fourth graders demonstrated knowledge that performance on a single task would be better than performance on the dual tasks for only 2 of the variables examined. In Experiment 2, in which the dual attention tasks were dissimilar (i.e., visual and auditory detection), kindergarten and 1st-grade children demonstrated knowledge that performance in the single task would be better than in the dual tasks for 1 of the task variables examined. However, 4th-grade children consistently gave higher ratings for performance on the single than on the dual attention tasks for all variables examined. These findings (a) underscore that children's meta-attention is not unitary and (b) demonstrate that children's knowledge about variables affecting attention sharing and resource allocation have different developmental pathways. Results show that knowledge about attention sharing and about the factors that influence the control of attention develops slowly and undergoes reorganization in middle childhood.

Genotypic variation in biomass allocation in response to field drought has a greater affect on yield than gas exchange or phenology.

PubMed

Edwards, Christine E; Ewers, Brent E; Weinig, Cynthia

2016-08-24

Plant performance in agricultural and natural settings varies with moisture availability, and understanding the range of potential drought responses and the underlying genetic architecture is important for understanding how plants will respond to both natural and artificial selection in various water regimes. Here, we raised genotypes of Brassica rapa under well-watered and drought treatments in the field. Our primary goal was to understand the genetic architecture and yield effects of different drought-escape and dehydration-avoidance strategies. Drought treatments reduced soil moisture by 62 % of field capacity. Drought decreased biomass accumulation and fruit production by as much as 48 %, whereas instantaneous water-use efficiency and root:shoot ratio increased. Genotypes differed in the mean value of all traits and in the sensitivity of biomass accumulation, root:shoot ratio, and fruit production to drought. Bivariate correlations involving gas-exchange and phenology were largely constant across environments, whereas those involving root:shoot varied across treatments. Although root:shoot was typically unrelated to gas-exchange or yield under well-watered conditions, genotypes with low to moderate increases in root:shoot allocation in response to drought survived the growing season, maintained maximum photosynthesis levels, and produced more fruit than genotypes with the greatest root allocation under drought. QTL for gas-exchange and yield components (total biomass or fruit production) had common effects across environments while those for root:shoot were often environment-specific. Increases in root allocation beyond those needed to survive and maintain favorable water relations came at the cost of fruit production. The environment-specific effects of root:shoot ratio on yield and the differential expression of QTL for this trait across water regimes have important implications for efforts to improve crops for drought resistance.

The marriage premium and compensating wage differentials.

PubMed

Reed, W R; Harford, K

1989-12-01

This paper proposes and tests an alternative explanation of the marriage premium that relies upon differences in workers' tastes and compensating wage differentials. A key assumption is that marital status proxies for the consumption of family goods, such as children, and that these are costly. Workers whose greater demands for family goods are taste- generated and shown to choose jobs that offer greater wage, and less non-pecuniary compensation. This creates an observed wage premium that has nothing to do with differences in workers' productivities. Supporting empirical evidence for this hypothesis is presented, including a reevaluation of previous studies.

Crystal structures of CaSiO3 polymorphs control growth and osteogenic differentiation of human mesenchymal stem cells on bioceramic surfaces.

PubMed

Zhang, Nianli; Molenda, James A; Mankoci, Steven; Zhou, Xianfeng; Murphy, William L; Sahai, Nita

2013-10-01

The repair and replacement of damaged or diseased human bone tissue requires a stable interface between the orthopedic implant and living tissue. The ideal material should be both osteoconductive (promote bonding to bone) and osteoinductive (induce osteogenic differentiation of cells and generate new bone). Partially resorbable bioceramic materials with both properties are developed by expensive trial-and-error methods. Structure-reactivity relationships for predicting the osteoinductive properties of ceramics would significantly increase the efficiency of developing materials for bone tissue engineering. Here we propose the novel hypothesis that the crystal structure of a bioceramic controls the release rates, subsequent surface modifications due to precipitation of new phases, and thus, the concentrations of soluble factors, and ultimately, the attachment, viability and osteogenic differentiation of human Mesenchymal Stem Cells (hMSCs). To illustrate our hypothesis, we used two CaSiO 3 polymorphs, pseudo-wollastonite (psw, β-CaSiO 3 ) and wollastonite (wol, α-CaSiO 3 ) as scaffolds for hMSC culture. Polymorphs are materials which have identical chemical composition and stoichiometry, but different crystal structures. We combined the results of detailed surface characterizations, including environmental Scanning Electron Microscopy (SEM) back-scattered imaging, and spot-analysis and 2D elemental mapping by SEM-Energy Dispersive X-ray (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM) and surface roughness analysis; culture medium solution analyses; and molecular/genetic assays from cell culture. Our results confirmed the hypothesis that the psw polymorph, which has a strained silicate ring structure, is more osteoinductive than the wol polymorph, which has a more stable, open silicate chain structure. The observations could be attributed to easier dissolution (resorption) of psw compared to wol, which resulted in concentration profiles that were more osteoinductive for the former. Thus, we showed that crystal structure is a fundamental parameter to be considered in the intelligent design of pro-osteogenic, partially resorbable bioceramics.

The origin of ovarian carcinomas: a unifying hypothesis.

PubMed

Auersperg, Nelly

2011-01-01

It is currently a controversial issue whether epithelial ovarian cancers arise in the ovarian surface epithelium (OSE) or the fimbrial epithelium of the oviduct. The hypothesis presented here aims to reconcile these 2 views and provides a possible explanation for 2 questions arising: first, why tumors originating in the fimbriae and OSE, which are parts of different organs, express common features; second, why these epithelia are prone to neoplastic transformation whereas the remaining oviduct and the extraovarian mesothelium are not. We hypothesize that these questions relate to the common origin of the OSE and fimbriae in that region of the embryonic coelomic epithelium, which will eventually link the extraovarian mesothelium to the epithelium of the oviductal ampulla. OSE and fimbriae become separated during embryonic development but, like other transitional, interepithelial junctions in adults, this region might remain incompletely committed and thus prone to neoplastic progression. To define differentiation at the OSE-tubal junction, salpingo-oophorectomy specimens were stained immunohistochemically for mesenchymal differentiation markers of OSE and for epithelial markers and Pax8, characterizing oviductal fimbriae and ampullae. OSE and ampullae were distinctly different, but there was no sharp boundary between OSE and fimbriae. Rather, both mesenchymal and epithelial markers overlapped, and Pax8 and fimbrial epithelial markers diminished distally, near the OSE. The results support the hypothesis that the OSE and fimbriae are parts of a transitional epithelium of common origin rather than 2 independent sources of ovarian cancer, and suggest that their immature, incompletely determined phenotype contributes to their propensity to neoplastic transformation.

Phylogeography of Sophora moorcroftiana Supports Wu's Hypothesis on the Origin of Tibetan Alpine Flora.

PubMed

Cheng, Shanmei; Qiong, La; Lu, Fan; Yonezawa, Takahiro; Yin, Ganqiang; Song, Zhiping; Wang, Yuguo; Yang, Ji; Zhang, Wenju

2017-06-01

Wu hypothesized that the Tibetan flora originated mostly from the paleotropical Tertiary flora in the Hengduan Mountains by adapting to the cold and arid environments associated with the strong uplift of the Qinghai-Tibet Plateau (QTP). Here, we combine the phylogeographic history of Sophora moorcroftiana with that of Sophora davidii to explore the speciation of S. moorcroftiana to test this hypothesis. We collected 151 individuals from 17 populations and sequenced 2 chloroplast fragments and the internal transcribed spacer of rDNA. Five chlorotypes and 9 ribotypes were detected but no significant phylogeographic structure was revealed. The integrated results of phylogeographic studies of these 2 species clearly support the progenitor-derivative relationship between them. We infer that the western peripheral population of S. davidii migrated westwards from the Hengduan Mountains to the middle reaches of the Yarlung Zangbo River and differentiated from its ancestor in the process of adaptation to increasingly cold and arid environments with the uplift of the QTP and finally evolved into S. moorcroftiana during the Late Pliocene. In addition, our findings shed light on the idea that natural selection, as imposed by climate differentiation (especially mean diurnal range and precipitation seasonality), directly drove this peripatric speciation event after geographic isolation. The speciation of S. moorcroftiana is a strong case supporting Wu's hypothesis about the origin of Tibet's flora. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Maternal investment in relation to sex ratio and offspring number in a small mammal – a case for Trivers and Willard theory?

PubMed Central

Koskela, Esa; Mappes, Tapio; Niskanen, Tuuli; Rutkowska, Joanna

2009-01-01

Optimal parental sex allocation depends on the balance between the costs of investing into sons vs. daughters and the benefits calculated as fitness returns. The outcome of this equation varies with the life history of the species, as well as the state of the individual and the quality of the environment. We studied maternal allocation and subsequent fecundity costs of bank voles, Myodes glareolus, by manipulating both the postnatal sex ratio (all-male/all-female litters) and the quality of rearing environment (through manipulation of litter size by −2/+2 pups) of their offspring in a laboratory setting. We found that mothers clearly biased their allocation to female rather than male offspring regardless of their own body condition. Male pups had a significantly lower growth rate than female pups, so that at weaning, males from enlarged litters were the smallest. Mothers produced more milk for female litters and also defended them more intensively than male offspring. The results agree with the predictions based on the bank vole life history: there will be selection for greater investment in daughters rather than sons, as a larger size seems to be more influencial for female reproductive success in this species. Our finding could be a general rule in highly polygynous, but weakly dimorphic small mammals where females are territorial. The results disagree with the narrow sense Trivers & Willard hypothesis, which states that in polygynous mammals that show higher variation in male than in female reproductive success, high-quality mothers are expected to invest more in sons than in daughters. PMID:19549147

Effects of Study Design and Allocation on participant behaviour--ESDA: study protocol for a randomized controlled trial.

PubMed

Kypri, Kypros; McCambridge, Jim; Wilson, Amanda; Attia, John; Sheeran, Paschal; Bowe, Steve; Vater, Tina

2011-02-14

What study participants think about the nature of a study has been hypothesised to affect subsequent behaviour and to potentially bias study findings. In this trial we examine the impact of awareness of study design and allocation on participant drinking behaviour. A three-arm parallel group randomised controlled trial design will be used. All recruitment, screening, randomisation, and follow-up will be conducted on-line among university students. Participants who indicate a hazardous level of alcohol consumption will be randomly assigned to one of three groups. Group A will be informed their drinking will be assessed at baseline and again in one month (as in a cohort study design). Group B will be told the study is an intervention trial and they are in the control group. Group C will be told the study is an intervention trial and they are in the intervention group. All will receive exactly the same brief educational material to read. After one month, alcohol intake for the past 4 weeks will be assessed. The experimental manipulations address subtle and previously unexplored ways in which participant behaviour may be unwittingly influenced by standard practice in trials. Given the necessity of relying on self-reported outcome, it will not be possible to distinguish true behaviour change from reporting artefact. This does not matter in the present study, as any effects of awareness of study design or allocation involve bias that is not well understood. There has been little research on awareness effects, and our outcomes will provide an indication of the possible value of further studies of this type and inform hypothesis generation. Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000846022.

Opportunistic detection of atrial fibrillation in subjects aged 65 years or older in primare care: a randomised clinical trial of efficacy. DOFA-AP study protocol.

PubMed

Pérula-de-Torres, Luis Á; Martínez-Adell, Miguel Á; González-Blanco, Virginia; Baena-Díez, José M; Martín-Rioboó, Enrique; Parras-Rejano, Juan M; González-Lama, Jesús; Martín-Alvarez, Remedios; Ruiz-Moral, Roger; Fernández-García, José Á; Pérez-Díaz, Modesto; Ruiz-de-Castroviejo, Joaquin; Pérula-de-Torres, Carlos; Valero-Martín, Antonio; Roldán-Villalobos, Ana; Criado-Larumbe, Margarita; Burdoy-Joaquín, Emili; Coma-Solé, Montserrat; Cervera-León, Mercè; Cuixart-Costa, Lluís

2012-10-30

Clinical Practice Guidelines recommend using peripheral blood pulse measuring as a screening test for Atrial Fibrillation. However, there is no adequate evidence supporting the efficacy of such procedure in primary care clinical practice. This paper describes a study protocol designed to verify whether early opportunistic screening for Atrial Fibrillation by measuring blood pulse is more effective than regular practice in subjects aged 65 years attending primary care centers. An cluster-randomized controlled trial conducted in Primary Care Centers of the Spanish National Health Service. A total of 269 physicians and nurses will be allocated to one of the two arms of the trial by stratified randomization with a 3:2 ratio (three practitioners will be assigned to the Control Group for every two practitioners assigned to the Experimental Group). As many as 12 870 patients aged 65 years or older and meeting eligibility criteria will be recruited (8 580 will be allocated to the Experimental Group and 4 290 to the Control Group). Randomization and allocation to trial groups will be carried out by a central computer system. The Experimental Group practitioners will conduct an opportunistic case finding for patients with Atrial Fibrillation, while the Control Group practitioners will follow the regular guidelines. The first step will be finding new Atrial Fibrillation cases. A descriptive inferential analysis will be performed (bivariate and multivariate by multilevel logistic regression analysis). If our hypothesis is confirmed, we expect Primary Care professionals to take a more proactive approach and adopt a new protocol when a patient meeting the established screening criteria is identified. Finally, we expect this measure to be incorporated into Clinical Practice Guidelines. The study is registered as NCT01291953 (ClinicalTrials.gob).

Fine root productivity varies along nitrogen and phosphorus gradients in high-rainfall mangrove forests of Micronesia

USGS Publications Warehouse

Cormier, Nicole; Twilley, Robert R.; Ewel, Katherine C.; Krauss, Ken W.

2015-01-01

Belowground biomass is thought to account for much of the total biomass in mangrove forests and may be related to soil fertility. The Yela River and the Sapwalap River, Federated States of Micronesia, contain a natural soil resource gradient defined by total phosphorus (P) density ranging from 0.05 to 0.42 mg cm−3 in different hydrogeomorphic settings. We used this fertility gradient to test the hypothesis that edaphic conditions constrain mangrove productivity through differential allocation of biomass to belowground roots. We removed sequential cores and implanted root ingrowth bags to measure in situ biomass and productivity, respectively. Belowground root biomass values ranged among sites from 0.448 ± 0.096 to 2.641 ± 0.534 kg m−2. Root productivity (roots ≤20 mm) did not vary significantly along the gradient (P = 0.3355) or with P fertilization after 6 months (P = 0.2968). Fine root productivity (roots ≤2 mm), however, did vary significantly among sites (P = 0.0363) and ranged from 45.88 ± 21.37 to 118.66 ± 38.05 g m−2 year−1. The distribution of total standing root biomass and fine root productivity followed patterns of N:P ratios as hypothesized, with larger root mass generally associated with lower relative P concentrations. Many of the processes of nutrient acquisition reported from nutrient-limited mangrove forests may also occur in forests of greater biomass and productivity when growing along soil nutrient gradients.