Weak Integration Research Articles

How preschoolers perceive danger – A study of inattentional bias

ABSTRACT Harmful threats can sometimes appear unexpectedly in the lives of young children, whose limited experience leads to a greater risk of endangerment. The current study adapted the Variant Odd Ball protocol to explore the effects of threat and familiarity on inattentional blindness (IB). This research evaluated reactions to presentations of evolutionarily relevant images such as millipedes, snakes, escargots, and snails, compared with reactions to evolutionarily irrelevant images such as syringes, knives, flashlights, and spoons. Respondents included three hundred and forty 4–5-year-old preschool children. The findings were as follows: (1) The property of familiarity plays an important role in preschool children’s IB to both evolutionarily relevant and irrelevant images, and highly familiar images were easier to detect than less familiar images; (2) the manipulation of images showed that the threat-relevant stimuli were not more likely to be detected than the non-threat-relevant stimuli; (3) no significant difference was found between the detection rates of evolutionarily relevant and irrelevant images. Preschool children have a lower detection rate of threat-relevant images (e.g., snake, knife) which may reflect their limited experience of danger and weaker integration of these threat-relevant images in the current study.

The impact of hybridization on upper first molar shape in robust capuchins (Sapajus nigritus x S. libidinosus)

To better understand the impact of hybridization on development and morphology, I analyze an understudied phenotype in hybrid morphology research: tooth shape. I apply a 2D geometric morphometric approach to compare variation in first upper molar cusp tip positions and crown outline shape among 31 crested capuchins (Sapajus nigritus), 37 bearded capuchins (S. libidinosus), and 44 hybrids (S. nigritus x S. libidinosus). A principal components analysis shows that group membership accounts for a significantly greater proportion of variance along the first major axis of M1 shape variation than does allometry. While most hybrids have S. nigritus-like M1s, several possess a transgressive M1 shape not observed in either parental species. Procrustes distances are greater in hybrids compared to the parental capuchins, and two-block partial least squares analyses show that hybrids exhibit weaker integration between cusp tip positions and crown outline shape. These results demonstrate that hybridization generates novel M1 shapes and support the hypothesis that destabilized development results in elevated phenotypic variance in hybrids. Further studies of dental shape in hybrid primates will generate important data for on-going efforts to detect potential hybrids in the hominin fossil record and to understand the evolutionary outcomes of anthropogenic hybridization.

Alteration of single-subject gray matter networks in major depressed patients with suicidality.

While regional brain alterations and functional connectivity in depressed suicidal patients have previously been reported, knowledge about gray matter (GM) structural networks is limited. The aim of this study was to explore the GM of depressed suicidal brains from the single-subject structural network level. This was a cross-sectional study, in which 50 healthy controls (HC, 31 ± 9 years), 50 major depressed patients without suicidality (NSD, 29 ± 10 years), and 50 major depressed patients with suicidality (SU, 29 ± 12 years) were enrolled. T1 -weighted images (T1 WI) were acquired with three-dimensional-magnetization prepared rapid gradient echo sequence in 3.0 T magnetic resonance. The analysis was performed using the automated Computational Anatomy Toolbox (CAT12) within Statistical Parametric Mapping while running MATLAB. The T1 images were segmented into GM, white matter, and cerebrospinal fluid. Then single-subject structural networks were constructed based on the morphological similarity of GM regions. Global network topological properties, including clustering coefficient (Cp ), characterpath length (Lp ), normalized clustering coefficient (γ), normalized characteristic path length (λ), small-worldness (σ), global efficiency (Eglob ), local efficiency (Eloc ), and nodal network topological properties, including nodal efficiency, degree, and betweenness centrality, were measured using graph theory analysis. Statistical tests performed were analysis of variance, Pearson correlation analysis, and multiple linear regression analysis. Decreased Eglob and increased shortest Lp were observed in SU group compared to HC and NSD groups (p < 0.05). The NSD and SU groups had an increased λ and decreased Eloc compared to the HC group (p < 0.05). Altered nodal efficiency was found in the fronto-striatum-limbic-thalamic circuit in the SU group compared with the HC and NSD groups (all p < 0.05). The GM network in the SU group showed decreased segregation and weaker integration, that is weaker small-worldness, compared to the NSD and HC groups. Abnormal nodal efficiency was found in the fronto-striatum-limbic-thalamic circuit in suicidal brains. This study provides new evidence for therapeutic targets for patients with depression and suicidality. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 3.

Intact lip-reading but weaker McGurk effect in individuals with high autistic traits

A weaker McGurk effect is observed in individuals with autism spectrum disorder (ASD); weaker integration is considered to be the key to understanding how low-order atypical processing leads to their maladaptive social behaviors. However, the mechanism for this weaker McGurk effect has not been fully understood. Here, we investigated (1) whether the weaker McGurk effect in individuals with high autistic traits is caused by poor lip-reading ability and (2) whether the hearing environment modifies the weaker McGurk effect in individuals with high autistic traits. To confirm them, we conducted two analogue studies among university students, based on the dimensional model of ASD. Results showed that individuals with high autistic traits have intact lip-reading ability as well as abilities to listen and recognize audiovisual congruent speech (Experiment 1). Furthermore, a weaker McGurk effect in individuals with high autistic traits, which appear under the without-noise condition, would disappear under the high noise condition (Experiments 1 and 2). Our findings suggest that high background noise might shift weight on the visual cue, thereby increasing the strength of the McGurk effect among individuals with high autistic traits.

The existence and uniqueness result for quasilinear stochastic PDEs with obstacle under weaker integrability conditions

We prove an existence and uniqueness result for quasilinear Stochastic PDEs with obstacle (in short OSPDE) under a weaker integrability condition on the coefficient and the barrier.

Price and volatility interrelationships in the wholesale spot electricity markets of the Central-Western European and Nordic region: a multivariate GARCH approach

This paper examines price and volatility interrelationships in five European, day-ahead, wholesale spot electricity markets. These include the French, German, Belgian and Dutch electricity markets, forming the Central-Western European (CWE) region, as well as the Nord Pool Spot electricity market, a pool market for the Nordic region. For this purpose, a novel VAR model with dummy variables was developed to model the conditional mean price, while the CCC-MGARCH model and a DCC-MGARCH model were used to model volatility. The results suggest that evidence of market integration, as measured by cross-mean spillovers and conditional correlation, do exist in the electricity markets under examination. Nevertheless, they also indicate that the CWE electricity markets are stronger integrated, while, on the other hand, weaker integration is observed between them and the Nordic electricity market. We attribute these findings to the fact that physical interconnection capacity is not sufficient for the electricity markets to become fully integrated.

Perceptual Development of Nasal Consonants in Children With Normal Hearing and in Children Who Use Cochlear Implants

This study was conducted to determine whether the perceptions of nasal consonants in children with normal hearing and children with cochlear implants were predicted by the discontinuity hypothesis. Methods Four groups participated: 8 adults, 8 children with normal hearing (ages 5-7 years), 8 children with normal hearing (ages 3.5-4 years), and 5 children with cochlear implants (ages 5-7 years). Stimuli were 128 nasal consonant + vowel (/m/ /n/ + /i/ /æ/ /u/ //) syllables produced by a male adult. Each syllable production was edited into 4 segment types: (a) 50-ms murmur, (b) 25-ms murmur + 25-ms transition, (c) 50-ms transition, and (d) full syllable. Developmental effects were observed across listener groups. The children performed better in the 25-ms murmur + 25-ms transition condition, which suggests that they benefit from an integrated perceptual cue. The children wearing cochlear implants performed poorer than children with normal hearing on all segments. Developmental differences in perception of nasal consonants were evident. Children wearing cochlear implants showed weaker integration and perception abilities compared to younger children with normal hearing. As predicted by the discontinuity hypothesis, the segment with the spectral discontinuity provided the strongest perceptual cues to place of articulation of nasals in children with normal hearing.

Integrable embeddings and foliations

A $k$-submanifold $L$ of an open $n$-manifold $M$ is called {\it weakly integrable (WI)} [resp. {\it strongly integrable (SI)}] if there exists a submersion $\Phi:M\rightarrow {\Bbb{E}}^{n-k}$ such that $L\subset \Phi^{-1}(0)$ [resp. $L= \Phi^{-1}(0)$]. In this work we study the following problem, first stated in a particular case by Costa et al. ({\it Invent. Math.} 1988): which submanifolds $L$ of an open manifold $M$ are WI or SI? For general $M$, we explicitly solve the case $k=n-1$ and provide necessary and sufficient conditions for submanifolds to be WI and SI in higher codimension. As particular cases we recover the theorem of Bouma and Hector ({\it Indagationes Math.} 1983) asserting that any open orientable surface is SI in ${\Bbb{E}}^3$, and Watanabe's and Miyoshi's theorems ({\it Topology} 1993 and 1995) claiming that any link is WI in an open $3$-manifold. In the case $M={\Bbb{E}}^n$ we fully characterize WI and SI submanifolds, we provide examples of $3$- and $7$-manifolds which are not WI and we show that a theorem by Miyoshi ({\it Topology} 1995) which states that any link in ${\Bbb{E}}^3$ is SI does not hold in general. The right analogue to Miyoshi's theorem is also proved, implying in particular the surprising result that no knot in ${\Bbb{E}}^3$ is SI. Our results applied to the theory of foliations of Euclidean spaces give rise to some striking corollaries: using some topological invariants we classify all the submanifolds of ${\Bbb{E}}^n$ which can be realized as proper leaves of foliations; we prove that ${\Bbb{S}}^3$ can be realized as a leaf of a foliation of ${\Bbb{E}}^n$, $n \geq 7$, but not in ${\Bbb{E}}^5$ or ${\Bbb{E}}^6$, which partially answers a question by Vogt ({\it Math. Ann.} 1993); we construct open $3$-manifolds which cannot be leaves of a foliation of any compact $4$-manifold but are proper leaves in ${\Bbb{E}}^4$. The theory of WI and SI submanifolds is a framework where many classical tools of differential and algebraic topology play a prominent role: Phillips-Gromov h-principle, Hirsh-Smale theory, complete intersections, Seifert manifolds, the theory of immersions and embeddings, obstruction theory, etc.

MORPHOLOGICAL INTEGRATION IN THE HOMININ DENTITION: EVOLUTIONARY, DEVELOPMENTAL, AND FUNCTIONAL FACTORS

As the most common and best preserved remains in the fossil record, teeth are central to our understanding of evolution. However, many evolutionary analyses based on dental traits overlook the constraints that limit dental evolution. These constraints are diverse, ranging from developmental interactions between the individual elements of a homologous series (the whole dentition) to functional constraints related to occlusion. This study evaluates morphological integration in the hominin dentition and its effect on dental evolution in an extensive sample of Plio- and Pleistocene hominin teeth using geometric morphometrics and phylogenetic comparative methods. Results reveal that premolars and molars display significant levels of covariation; that integration is stronger in the mandibular dentition than in the maxillary dentition; and that antagonist teeth, especially first molars, are strongly integrated. Results also show an association of morphological integration and evolution. Stasis is observed in elements with strong functional and/or developmental interactions, namely in first molars. Alternatively, directional evolution (and weaker integration) occurs in the elements with marginal roles in occlusion and mastication, probably in response to other direct or indirect selective pressures. This study points to the need to reevaluate hypotheses about hominin evolution based on dental characters, given the complex scenario in which teeth evolve.

Comparison of Mandibular Phenotypic and Genetic Integration between Baboon and Mouse

In this study we compare patterns of mandibular integration between mice and baboons using both phenotypic and quantitative genetic data. Specifically, we test how well each species fits with the mosaic model of mandibular integration suggested by Atchley and Hall (Biol Rev Camb Philos Soc 66:101-157, 1991) based on developmental modules. We hypothesize that patterns of integration will be similar for mice and baboons and that both species will show strong integration within developmental modules and weaker integration between modules. Corresponding landmark data were collected from the hemi-mandibles of an advanced intercross mouse sample (N = 1239) and mandibles from a baboon sample of known pedigree from the Southwest Foundation for Biomedical Research (N = 430). We used four methods of analysis to quantify and compare the degree of mandibular integration between species including two methods based on a priori assumptions, and two a posteriori analyses. We found that patterns of integration are broadly similar for baboon and mouse mandibles, with both species displaying a modular pattern of integration. While there is a general trend of similarity in integration patterns between species, there were some marked differences. Mice are strongly correlated among distances within the coronoid process and the incisive alveolar region, whereas baboons are strongly integrated within the condylar process. We discuss the potential evolutionary implications of the similar patterns of integration between these species with an emphasis on the role of modularity.

Nonexistence of Self-similar Singularities in the Ideal Magnetohydrodynamics

In this paper we exclude the scenario of the apparition of finite time singularity in the form of self-similar singularities in the ideal magnetohydrodynamic equations, assuming suitable integrability conditions on the vorticity and the magnetic field. We also consider the more refined possibility of asymptotically self-similar singularities, where the local classical solution converges to the self-similar profile as we approach the possible time of singularity. The scenario of asymptotically self-similar singularity is also excluded under suitable conditions on the profile. In the two-dimensional magnetohydrodynamics the magnetic field evolution equations reduce to a divergence free transport equation for a scalar stream function. This helps us to improve the above nonexistence theorems on the self-similar singularities, in the sense that we require merely weaker integrability conditions on the profile in order to prove the results.

SERIAL HOMOLOGY AND THE EVOLUTION OF MAMMALIAN LIMB COVARIATION STRUCTURE

The tetrapod forelimb and hindlimb are serially homologous structures that share a broad range of developmental pathways responsible for their patterning and outgrowth. Covariation between limbs, which can introduce constraints on the production of variation, is related to the duplication of these developmental factors. Despite this constraint, there is remarkable diversity in limb morphology, with a variety of functional relationships between and within forelimb and hindlimb elements. Here we assess a hierarchical model of limb covariation structure based on shared developmental factors. We also test whether selection for morphologically divergent forelimbs or hindlimbs is associated with reduced covariation between limbs. Our sample includes primates, murines, a carnivoran, and a chiropteran that exhibit varying degrees of forelimb and hindlimb specialization, limb size divergence, and/or phylogenetic relatedness. We analyze the pattern and significance of between-limb morphological covariation with linear distance data collected using standard morphometric techniques and analyzed by matrix correlations, eigenanalysis, and partial correlations. Results support a common limb covariation structure across these taxa and reduced covariation between limbs in nonquadruped species. This result indicates that diversity in limb morphology has evolved without signficant modifications to a common covariation structure but that the higher degree of functional limb divergence in bats and, to some extent, gibbons is associated with weaker integration between limbs. This result supports the hypothesis that limb divergence, particularly selection for increased functional specialization, involves the reduction of developmental factors common to both limbs, thereby reducing covariation.

Cytochrome P-450scc induces vesicle aggregation through a secondary interaction at the adrenodoxin binding sites (in competition with protein exchange)

Addition of bovine adrenal cytochrome P-450scc to small unilamellar dioleoylphosphatidylcholine vesicles (DOPC-SUV) produces a complex sequence of interactions, indicating exceptional cytochrome mobility. First, cholesterol transfer from cytochrome to vesicles indicated rapid dissociation of P-450scc oligomers and integration of monomers into the membrane (delta A 390-420 nm; t1/2 = 2 s). After 10-15 s, P-450scc-induced aggregation of the vesicles starts, as indicated by increased turbidity (delta A 448 or 520 nm; complete in 6-8 min). Fluorescence quenching experiments indicate that this aggregation does not lead to measurable vesicle fusion during this period. Aggregation is prevented by mild heat denaturation of P-450scc, by addition of anti-P-450scc IgG, and also by 1:1 complex formation with the electron donor adrenodoxin (ADX). P-450scc, therefore, links two vesicles through two separate domains involved in, respectively, membrane integration (lipophilic) and ADX binding (charged). Although completely bound by DOPC-SUV, as evidenced by Sephadex elution, P-450scc has access within 1 min to cholesterol in secondary SUV. This is indicated by spectral changes (cholesterol complex formation) and by metabolism of secondary vesicle cholesterol. Since cholesterol equilibrates slowly between vesicles (t1/2 = 1-2 h), these changes arise from P-450scc transfer. This transfer was maximally slowed after a 5-min preincubation with primary vesicles, reflecting more extensive integration into the membrane than is necessary for the rapid initial cholesterol transfer to P-450scc. P-450scc transfer probably results from simultaneous interaction of P-450scc with two vesicles that may also initiate aggregation. Weaker integration into primary dimyristoylphosphatidylcholine vesicles facilitates exchange but prevents aggregation. Integration and aggregation are both enhanced by incorporation of 10% phosphatidylinositol into SUV, while exchange is slowed. This mobility of P-450scc is most probably a consequence of the absence of amino-terminal anchoring. P-450scc-induced association of inner mitochondrial membrane segments may contribute to the exceptionally vesiculated structure of adrenal and ovarian mitochondria that parallels increased P-450scc content.