Dominance Hypothesis Research Articles

Strong IR cancellation in heavy quarkonium and precise top mass determination

Combining recent perturbative analyses on the static QCD potential and the quark pole mass, we find that, for the heavy quarkonium states $c\bar{c}$, $b\bar{b}$ and $t\bar{t}$, (1) ultra-soft (US) corrections in the binding energies are small, and (2) there is a stronger cancellation of IR contributions than what has been predicted by renormalon dominance hypothesis. By contrast, for a hypothetical heavy quarkonium system with a small number of active quark flavors ($n_l\approx 0$), we observe evidence that renormalon dominance holds accurately and that non-negligible contributions from US corrections exist. In addition, we examine contributions of renormalons at $u=- 1$. As an important consequence, we improve on a previous prediction for possible achievable accuracy of top quark $\overline{\rm MS}$--mass measurement at a future linear collider and estimate that in principle 20--30~MeV accuracy is reachable.

Nonparametric tests of conditional treatment effects with an application to single-sex schooling on academic achievements

Summary We develop a general class of nonparametric tests for treatment effects conditional on covariates. We consider a wide spectrum of null hypotheses regarding conditional treatment effects, including the following: (a) the null hypothesis of the conditional stochastic dominance between treatment and control groups; (b) the null hypothesis that the conditional average treatment effect is nonpositive for each value of covariates; (c) the null hypothesis of no distributional (or average) treatment effect conditional on covariates. The test statistics are based on L1-type functionals of uniformly consistent nonparametric kernel estimators of conditional expectations that characterize the null hypotheses. We show that our tests using the standard normal critical values have asymptotically correct size. We also show that the proposed nonparametric tests are consistent against general fixed alternatives and have non-negligible powers against some n−1/2 local alternatives to the null hypothesis with inequality constraints and n−1/2h−d/4 local alternatives to the null hypothesis with equality constraints, where h is a bandwidth, n is the sample size and d is the dimension of continuous covariates. We illustrate the usefulness of our tests by applying them to the effect of single-sex schooling on academic achievements using Korean data.

Cold tolerance, and not earlier arrival on breeding grounds, explains why males winter further north in an Arctic‐breeding songbird

Sex biases in distributions of migratory birds during the non‐breeding season are widespread; however, the proximate mechanisms contributing to broad‐scale sex‐ratio variation are not well understood. We analyzed a long‐term winter‐banding dataset in combination with spring migration data from individuals tracked by using geolocators to test three hypotheses for observed variation in sex‐ratios in wintering flocks of snow buntings Plectrophenax nivalis. We quantified relevant weather conditions in winter (temperature, snowfall and snow depth) at each banding site each year and measured body size and condition (fat scores) of individual birds (n > 5500). We also directly measured spring migration distance for 17 individuals by using light‐level geolocators. If the distribution pattern of birds in winter is related to interactions between individual body size and thermoregulation, then larger bodied birds (males) should be found in colder sites (body size hypothesis). Males may also winter closer to breeding grounds to reduce migration distance for early arrival at breeding sites (arrival timing hypothesis). Finally, males may be socially dominant over females, and thus exclude females from high‐quality wintering sites (social dominance hypothesis). We found support for the body size hypothesis, in that colder and snowier weather predicted both larger body size and higher proportions of males banded. Direct tracking revealed that males did not winter significantly closer to their breeding site, despite being slightly further north on average than females from the same breeding population. We found some evidence for social dominance, in that females tended to carry more fat than males, potentially indicating lower habitat quality for females. Global climatic warming may reduce temperature constraints on females and smaller‐bodied males, resulting in broad‐scale changes in distributional patterns. Whether this has repercussions for individual fitness, and therefore population demography, is an important area of future research.

When do plant radiations influence community assembly? The importance of historical contingency in the race for niche space.

Plant radiations are widespread but their influence on community assembly has rarely been investigated. Theory and some evidence suggest that radiations can allow lineages to monopolize niche space when founding species arrive early into new bioclimatic regions and exploit ecological opportunities. These early radiations may subsequently reduce niche availability and dampen diversification of later arrivals. We tested this hypothesis of time-dependent lineage diversification and community dominance using the alpine flora of New Zealand. We estimated ages of 16 genera from published phylogenies and determined their relative occurrence across climatic and physical gradients in the alpine zone. We used these data to reconstruct occupancy of environmental space through time, integrating palaeoclimatic and palaeogeological changes. Our analysis suggested that earlier-colonizing lineages encountered a greater availability of environmental space, which promoted greater species diversity and occupancy of niche space. Genera that occupied broader niches were subsequently more dominant in local communities. An earlier time of arrival also contributed to greater diversity independently of its influence in accessing niche space. We suggest that plant radiations influence community assembly when they arise early in the occupancy of environmental space, allowing them to exclude later-arriving colonists from ecological communities by niche preemption.

Recent Advances in Understanding Plant Heterosis

Although heterosis is widely utilized in crop production, its genetic and molecular basis is still elusive. It is arguably that heterosis arises in crosses between genetically and/or epigenetically distinct individuals. Various genetic models have been proposed to explain heterosis, such as dominance and overdominance hypothesis. With the recent advancements in functional genomics, epigenetics, transcriptomics, proteomics, and metabolomics-related technologies, systems-level approaches have been adopted to understand the molecular basis of heterosis. In this review, we gather a brief account of findings from various studies in order to better understand the genetic and molecular basis of heterosis.

Emotional task management: neural correlates of switching between affective and non-affective task-sets.

Although task-switching has been investigated extensively, its interaction with emotionally salient task content remains unclear. Prioritized processing of affective stimulus content may enhance accessibility of affective task-sets and generate increased interference when switching between affective and non-affective task-sets. Previous research has demonstrated that more dominant task-sets experience greater switch costs, as they necessitate active inhibition during performance of less entrenched tasks. Extending this logic to the affective domain, the present experiment examined (a) whether affective task-sets are more dominant than non-affective ones, and (b) what neural mechanisms regulate affective task-sets, so that weaker, non-affective task-sets can be executed. While undergoing functional magnetic resonance imaging, participants categorized face stimuli according to either their gender (non-affective task) or their emotional expression (affective task). Behavioral results were consistent with the affective task dominance hypothesis: participants were slower to switch to the affective task, and cross-task interference was strongest when participants tried to switch from the affective to the non-affective task. These behavioral costs of controlling the affective task-set were mirrored in the activation of a right-lateralized frontostriatal network previously implicated in task-set updating and response inhibition. Connectivity between amygdala and right ventrolateral prefrontal cortex was especially pronounced during cross-task interference from affective features.

Relations between the QCD sum rules for BBV couplings and vector-dominance model

Story of QCD sum rules is briefly reviewed. The dispersion superconvergence sum rule is shown to relate πN coupling constant with the 33-resonance width without unitary symmetry arguments. The QCD sum rules instead reveal the unitary symmetry pattern as all the correlation functions can be reduced to 2 ones repeating the F and D couplings for the octet baryons 1/2+. Strong relations between the correlators are established. Vector dominance hypothesis allows to put new restrictions to the QCD sum rules for VBB couplings.

Northern flicker mates foraging on renewing patches within home ranges avoid competition not by separate niches but by segregation

Foraging with others can reduce predation risk but may increase competition for resources. Species, sex, or age classes may use different niches to reduce competition for food, which may be enforced by social dominance or may lead to ecological specialization. An alternate hypothesis is that individuals using resource patches that renew over time intentionally avoid recently depleted patches by avoiding each other. We tested these hypotheses by simultaneously radio-tracking northern flicker (Colaptes auratus) mates. Members of a pair rarely foraged in the same patch, spending over 90 % of the time >50 m apart. Counter to the ecological specialization hypothesis, the types of ground cover used for foraging and the distance of foraging patches from cover and edge did not differ between males and females. Mates were more spatially segregated on the home range than random and males foraged closer to the nest than females, but we never saw agonistic behaviors counter to the dominance hypothesis. Both sexes avoided returning to the same foraging location repeatedly, perhaps because of prey depletion. We suggest that members of a pair avoided foraging close to each other to reduce encounters with depleted prey patches. We emphasize the importance of simultaneous tracking of mates to identify foraging strategies and potential niche segregation at the home range scale.

The influence of emotional faces on the spatial allocation of attention

Background objectives: Studies suggest that the right hemisphere is dominant for emotional facial recognition. In addition, whereas some studies suggest the right hemisphere mediates the processing of all emotions (dominance hypothesis), other studies suggest that the left hemisphere mediates positive emotions the right mediates negative emotions (valence hypothesis). Since each hemisphere primarily attends to contralateral space, the goals of this study was to learn if emotional faces would induce a leftward deviation of attention and if the valence of facial emotional stimuli can influence the normal viewer’s spatial direction of attention. Methods: Seventeen normal right handed participants were asked to bisect horizontal lines that had all combinations of sad, happy or neutral faces at ends of these lines. During this task the subjects were never requested to look at these faces and there were no task demands that depended on viewing these faces. Results: Presentation of emotional faces induced a greater leftward deviation compared to neutral faces, independent of where (spatial position) these faces were presented. However, faces portraying negative emotions tended to induce a greater leftward bias than positive emotions. Conclusions: Independent of location, the presence of emotional faces influenced the spatial allocation of attention, such that normal subjects shift the direction of their attention toward left hemispace and this attentional shift appears to be greater for negative (sad) than positive faces (happy).

Convergent models of handedness and brain lateralization.

The pervasive nature of handedness across human history and cultures is a salient consequence of brain lateralization. This paper presents evidence that provides a structure for understanding the motor control processes that give rise to handedness. According to the Dynamic Dominance Model, the left hemisphere (in right handers) is proficient for processes that predict the effects of body and environmental dynamics, while the right hemisphere is proficient at impedance control processes that can minimize potential errors when faced with unexpected mechanical conditions, and can achieve accurate steady-state positions. This model can be viewed as a motor component for the paradigm of brain lateralization that has been proposed by Rogers et al. (MacNeilage et al., 2009) that is based upon evidence from a wide range of behaviors across many vertebrate species. Rogers proposed a left-hemisphere specialization for well-established patterns of behavior performed in familiar environmental conditions, and a right hemisphere specialization for responding to unforeseen environmental events. The dynamic dominance hypothesis provides a framework for understanding the biology of motor lateralization that is consistent with Roger's paradigm of brain lateralization.

The Spouse's Level of Education and Individuals' Dietary Behaviors in China.

There has been a growing interest in understanding relationships between educational attainment of an individual and his or her spouse's health. However, the issue has not been extensively studied, particularly in East Asian nations. We investigated the relation between individuals' specific dietary behaviors and their spouses' educational attainment in China. A total of 2071 individuals were surveyed in the 2012 Zhuzhou Healthy City Project, in China. Multivariate logistic regressions were used to model two specific individual dietary behaviors (i.e., oil intake and salt intake) as a function of own and their spouses' educational attainment. The models were also constructed by gender. Spouses' education was positively associated both with individuals' oil intake and salt intake after adjusting for the demographic characteristics, socioeconomic status, and health knowledge. Also, females (i.e., wives) were more likely to benefit from her spouse's education in terms of healthy dietary behaviors. When his or her spouse's level of education were greater, an individual was more likely to meet the dietary guidelines of salt and oil intakes. This Chinese study supports the male dominance hypothesis (i.e., males are more influential on female's health behavior) and the highest status dominance hypothesis (i.e., individuals with higher socioeconomic status are more influential on those with lower status). In terms of the social cognitive theory, married couples exchange health knowledge and share health behaviors. Spouses' educational attainment and health knowledge should be incorporated into the design of health promotion programs targeting married couples in China. Finally, additional theoretical explanations and implications are evaluated in this article.

Plant trait–digestibility relationships across management and climate gradients in permanent grasslands

Summary Dry matter digestibility is a critical component of herbage nutritive value, a major service delivered by grasslands. The aim of this study was to test whether the dominance hypothesis applies to assess the impacts of environmental gradients and management regimes on this component of herbage nutritive value in permanent grasslands. At the plant level, digestibility has been related to a number of functional traits, but whether this can be scaled up to the community level in species‐rich grasslands and how such relationships are modulated by environmental conditions and management regimes remain unknown. Our primary objective was to test whether community‐weighted means – species trait values weighted by the species abundance – of morphological, phenological and chemical traits could be used to explain variations in digestibility over a large range of climatic contexts, soil resource levels and management regimes. Our second objective was to explain variations in community digestibility within and among nine contrasting sites along large natural and man‐induced environmental gradients. Over the whole data set, digestibility and most community‐weighted means of traits responded to climatic factors and management regimes, but relations were not always significant when each site was considered separately. Community digestibility was significantly related to one or more plant traits within each site and to all of the measured traits when considering all the sites. Leaf dry matter content (LDMC) had the most consistent effects on digestibility, with a strikingly similar negative effect within each site. Potential evapotranspiration was negatively related to digestibility and contributed to explain a large part of the among‐site variance. In addition, a low return interval of disturbance and a high disturbance intensity (biomass removal) were both associated with a high digestibility. Synthesis and applications. Disturbance regime, plant traits and local climate impacted dry matter digestibility roughly equally in grasslands. The effects of community composition on digestibility and its response to abiotic factors could be successfully captured by community‐weighted means of leaf dry matter content. This functional marker can be used to develop indicators and grassland management rules to support farmers in the refinement of their practices towards specific needs, such as target production outputs.

TYPES OF GENE ACTION AND HYBRID VIGOUR FOR YIELD AND QUALITY TRAITS OF MELON (CUCUMIS MELO, L.).

This study was carried out in two successive summer seasons (2012 and 2013), at the Experimental Farm of Research Station, Qanater El-Khairya, El- Kalupia Governorate, Agriculture Research Center. The main objectives of this investigation were to estimate of magnitude of additive and non-additive gene effects for some traits in an attempt to stablish some inbred lines. The study also aimed to estimate heterosis degree, relative to mid, better parents and the standard cultivar to determine the hybrid vigour for some important characters. Phenotypic correlation coefficients between all possible pairs of the different studied traits were estimated. The following traits were assessed: early and total yield as fruit number and weight, average fruit weight, shape index, skin and flesh colour, flesh thickness, β carotene, vitamin C and sugars contents. The obtained results showed that both additive and non-additive gene effects were involved, the additive gene effects appeared to be playing the main role in the inheritance of all studied traits, since the estimated GCA: SCA ratio values ranged from 4.4 to 57.8. None of the parents found to be good combiner for all characters. Generally the two parents Magyar Kincs and Muszkotaly were the best combiner for breeding to most characters. It is noticed that the bestcombinations were resulted from crossing between these two parents or between one of them and other parent. Hybrid vigour was detected for early and total yield, as well as, most fruit characters. In some crosses, high better parent heterosis and potence ratio values were given for these traits supporting the over dominance hypothesis. Other degrees of dominance were observed by many crosses concerning some traits. High estimated standard heterosis were reflected by three crosses i.e., Shahd El-Dokki X Muszkotaly, Shahd El-Dokki X Magyar Kincs and Magyar Kincs X Muszkotaly for yield and most important traits. Hence, it could be suggested that these crosses may be recommended as new promising hybrids for commercial production of melon after further evaluation. Desirable correlations were detected between many pairs of character. In many cases phenotypic correlations used to help breeders in selecting and improving quantitative of difficulty measured characters through the selection for simply and correlated ones.

Testing the Stem Dominance Hypothesis: Meaning Analysis of Inflected Words and Prepositional Phrases

We tested the hypothesis that lexical-semantic access of inflected words is governed by the word stem. Object drawings overlaid with a dot/arrow marking position/movement were matched with corresponding linguistic expressions like “from the house”. To test whether the stem dominates lexical-semantic access irrespective of its position, we used Swedish prepositional phrases (locative information via preposition immediately preceding the stem) or Finnish case-inflected words (locative information via suffix immediately following the stem). Both in monolingual Swedish and in bilingual Finnish-Swedish speakers, correct stems with incorrect prepositions/case-endings were hardest to reject. This finding supports the view that the stem is indeed the dominant unit in meaning access of inflected words.

China's Dominance Hypothesis and the Emergence of a Tri-polar Global Currency System

This study assesses whether the international monetary system is already tri-polar by testing what we call China's ‘dominance hypothesis’, i.e. whether the renminbi already influences exchange rate and monetary policies strongly in Asia, a direct reference to the old ‘German dominance hypothesis’ which ascribed to the German mark a dominant role in Europe in the 1980s. Using a global factor model of exchange rates and a complementary event study, we find evidence that the renminbi has become a key driver of currency movements in Asia since the mid-2000s, especially since the global financial crisis, in line with China's dominance hypothesis.

Probing L-violating coupling via sbottom resonance production at the LHeC

We investigate the resonant production of the lighter sbottom at the proposed Large Hadron Electron Collider (LHeC) and its subsequent decay into e- + jet final state, under the single coupling dominance hypothesis in the framework of the R-parity-violating (RPV) minimal supersymmetric Standard Model (MSSM). It is concluded that the LHeC running at the high electron beam energy configuration of Ee = 150 GeV would provide excellent opportunities to search for the sbottom resonance and probe the lepton-number-violating [Formula: see text]-type Yukawa interaction. With about 1 fb-1 integrated luminosity expected in Ee = 150 GeV e-p collision at the LHeC, either the lighter sbottom RPV resonance could be directly detected up to 1 TeV, or the L-violating coupling [Formula: see text] could be constrained at an unprecedented level of precision compared with all the knowledge derived from indirect measurements.

Consistent Nonparametric Tests for Lorenz Dominance

This article proposes consistent nonparametric methods for testing the null hypothesis of Lorenz dominance. The methods are based on a class of statistical functionals defined over the difference between the Lorenz curves for two samples of welfare-related variables. We present two specific test statistics belonging to the general class and derive their asymptotic properties. As the limiting distributions of the test statistics are nonstandard, we propose and justify bootstrap methods of inference. We provide methods appropriate for case where the two samples are independent as well as the case where the two samples represent different measures of welfare for one set of individuals. The small sample performance of the two tests is examined and compared in the context of a Monte Carlo study and an empirical analysis of income and consumption inequality.

The Implications of Increased Body Size in the Song Sparrows of the California Islands

We investigated morphological divergence between mainland and California Island populations of the Song Sparrow (Melospiza melodia). Body size in small terrestrial vertebrates has been hypothesized to be larger in island forms than in their mainland relatives. Previously, we established that although bill size in island populations was similar to that in mainland populations with similar climate, bill-size dimorphism averaged much greater on the islands. In this paper, we compare various measures of structural body size and body mass between the California Islands and the mainland. We found that average body mass is over 10% higher in island Song Sparrows than in comparable mainland populations. However, a lack of commensurate structural body size suggests that body condition might be better in island Song Sparrows. This higher size-corrected mass may be explained by the dominance hypothesis, greater food availability and/or reduced competition, or adaptive mass regulation in the face of reduced predation pressure on adults. Both greater sexual bill dimorphism and greater body mass suggest reduced competition for food for the island Song Sparrow: a possibility that invites further investigation.

Modulation of cortical vestibular processing by somatosensory inputs in the posterior insula

Primary objective: To study the mechanism of somatosensory-vestibular interactions, this study examined the effects of somatosensory inputs on body sway induced by galvanic vestibular stimulation (GVS) in healthy participants and persons with brain injury in the posterior insula, a region constituting a part of the parietoinsular vestibular cortex.Research design: This study adopted an experimental, controlled, repeated measures design.Methods and procedures: Participants were 11 healthy individuals, two persons with unilateral posterior insular injury and two age-matched controls. Bipolar GVS was applied to the mastoid processes while participants were sitting with their eyes closed, either lightly touching a stable surface with their index finger or not touching the surface with their index finger.Main outcomes and results: In healthy participants, tilting was greater with right hemispheric stimulation than with left hemispheric stimulation. Moreover, with right hemispheric stimulation, tilting was greater with a right finger touch than with no touch. The person with right-brain injury showed tilting induced by GVS; however, finger touch had no modulatory effect. In contrast, finger touch enhanced tilting in the person with left-brain injury.Conclusions: These preliminary results are discussed in light of a hypothesis of right hemispheric dominance of somatosensory-vestibular interactions in the posterior insula.

The effect of peer group performance on the self-concept of reading in a foreign language

According to the big-fish-little-pond (BFLP) model, the self-concept is not only influenced in a positive way by one’s own achievement, but also in a negative way by one’s relative achievement in comparison with one’s immediate peers. This study investigates whether the BFLP effect also holds for second language acquisition. A random sample of 9167 Dutch-speaking students from Grade 8 took a reading comprehension test in French followed by a short background questionnaire in which they were asked for their self-concept of reading French. Multilevel regressions of the latter on individual and group achievement confirmed the BFLP effect but did not confirm an interaction of the effect with gender, individual achievement or class size. Moreover, in line with the local dominance hypothesis, it was shown that the negative effect of the average performance of peers is stronger for classmates than for schoolmates.