Mutual Exclusion Principle Research Articles

Evidence for Solution-State Nonlinearity of sp-Carbon Chains Based on IR and Raman Spectroscopy: Violation of Mutual Exclusion

Adamantyl-end-capped polyynes with chains of 4, 6, 8, 10, 12, 16, and 20 sp-hybridized carbons (C4-C20) have been synthesized and their IR and Raman spectra obtained. On the basis of violations of the mutual-exclusion principle between IR and Raman spectroscopy, spectral evidence demonstrates that these molecules possess a noncentrosymmetric molecular structure in both the solid and solution states. This premise is supported by X-ray crystallographic analysis of C12, which shows a bent, noncentrosymmetric structure in the solid state. Density functional theory (DFT) calculations for adamantyl-end-capped polyynes, in comparison with those for hydrogen-end-capped polyynes, show that the observed violation of mutual exclusion is independent of the end group of the polyyne chain (i.e., adamantyl versus H). The origin of these experimental spectroscopic observations is ascribed to the existence of dynamic contributions to molecular nonlinearity resulting from low-frequency skeletal bending vibrations of the chains and/or the existence of low-energy bent conformations of the polyyne chains, as DFT-optimized structures seem to suggest.

Three- and four-year-olds spontaneously use others’ past performance to guide their learning

A wealth of human knowledge is acquired by attending to information provided by other people – but some people are more credible sources than others. In two experiments, we explored whether young children spontaneously keep track of an individual’s history of being accurate or inaccurate and use this information to facilitate subsequent learning. We found that 3- and 4-year-olds favor a previously accurate individual when learning new words and learning new object functions and applied the principle of mutual exclusivity to the newly learned words but not the newly learned functions. These findings expand upon previous research in a number of ways, most importantly by showing that (a) children spontaneously keep track of an individual’s history and use it to guide subsequent learning without any prompting, and (b) children’s sensitivity to others’ prior accuracy is not specific to the domain of language.

Bacterially Produced Manganese Oxide and Todorokite: UV Raman Spectroscopic Comparison

UV Raman spectroscopic data measured at two distinct conditions, low and high laser power, establish that the manganese oxide (SP6-MnOx) produced by the freshwater bacterium (Leptothrix discophora SP-6) closely resembles the 3 × 3-tunnel todorokite among the MnO2 materials studied. Under the two conditions, the effect of hydration/cation and the phase transition of todorokite or SP6-MnOx to Mn3O4 or birnessite will be described. A higher concentration of Mg2+ incorporated in the framework of the SP6-MnOx than in todorokite is probably responsible for the formation of a new Raman band obtained at high laser powers, matching the most intense UV Raman band of synthetic birnessite. Also, we present the assignment of Raman bands for todorokite mineral and discuss the mutual exclusion principle that should hold for all the MnO2 materials studied. These experiments provide characterization of hydrous, poorly crystalline, or nanocrystalline metal oxides, which are frequently difficult to identify.

Young monolingual and bilingual children's responses to violation of the Mutual Exclusivity Principle

The mutual exclusivity principle, which states that an object category can have only one name, has been shown to be used by toddlers and preschoolaged children(Markman, 1991). Studies of the mutual exclusivity principle in bilingual children aged over 3.5 years have generally found a tendency to honor the principle within languages, but not across languages. To date, younger bilinguals'adherence to this principle has not been investigated. In the present cross-sectional study, monolingual and bilingual children aged 27 and 35 months were tested. Both monolingual and bilingual children were presented with two novel labels for the same object, a violation of the mutual exclusivity principle within a language. They were then tested on their comprehension of the two labels. Bilingual children participated in an additional task in which mutual exclusivity was violated across languages Results indicated that across both language groups, the older children honored mutual exclusivity more than the younger children. No differences were found between monolinguals and bilinguals in adherence to mutual exclusivity. In addition, bilingual children performed similarly when mutual exclusivity was violated within a language and across languages The proportion of translation equivalents in the bilingual children's vocabulary did not predict their performance on the mutual exclusivity task. These results suggest that bilingual language experience does not significantly alter adherence to the mutual exclusivity principle before the age of three years.

Phase relationships in cobalt iodate hydrates — thermal analyses, X-ray, IR, and Raman spectroscopic studies

The phase relationships of the cobalt iodate–water system have been examined using thermal analyses (DSC, TG), X-ray, IR and Raman spectroscopic methods. The compounds established are Co(IO 3) 2·4H 2O, α-Co(IO 3) 2·2H 2O, β-Co(IO 3) 2·2H 2O, Co(IO 3) 2 as well as the novel compounds Co(IO 3) 2· xH 2O and Co(IO 3) 2·H 2O. β-Co(IO 3) 2·2H 2O is isostructural to the respective nickel compound. Co(IO 3) 2·H 2O crystallises orthorhombic with a=827.18(6) pm, b=1104.52(8) pm, and c=772.26(4) pm. The vibrational spectra display acentric space groups (violation of the mutual exclusion principle) for Co(IO 3) 2·H 2O and Co(IO 3) 2. β-Co(IO 3) 2·2H 2O dehydrates to Co(IO 3) 2, Co(IO 3) 2· xH 2O at ∼300 K (TG) to Co(IO 3) 2·H 2O, and Co(IO 3) 2·H 2O at 519 K (DSC) to Co(IO 3) 2. Both the strength of the hydrogen bonds and the colour of the various cobalt iodate hydrates differ strongly. This is caused by the different ligand field splitting of the respective Co(IO 3) x (H 2O) y polyhedra. The former is shown from the average wave numbers of the uncoupled OD stretching modes (isotopically dilute samples), which decrease in the range Co(IO 3) 2·H 2O (pale-pink, ν OD: 2302 and 2248 cm −1, 90 K)<α-Co(IO 3) 2·2H 2O (pink, ν OD: 2453, 2423, and 2×2315 cm −1)<Co(IO 3) 2·4H 2O (wine-red)<β-Co(IO 3) 2·2H 2O (violet, ν OD: 2519 and 2424 cm −1).

Restricting a Familiar Name in Response to Learning a New One: Evidence for the Mutual Exclusivity Bias in Young Two-Year-Olds

Children under 2 1/2 years old tend to interpret novel words in accordance with the Mutual Exclusivity Principle, but tend not to reinterpret familiar words this way. Because alternative principles have been proposed that only predict the novel word effects, and because tests of the familiar word effects may have been flawed, a new test was administered. In Experiment 1 (N = 32), 24- to 25-month-olds heard stories in which a novel noun was used for an atypical exemplar of a familiar noun. When asked to select exemplars of the familiar noun, they showed a small but reliable tendency to avoid the object from the story. In Experiment 2 (N = 16), the novel nouns in the stories were replaced by pronouns and proper names, and the children did not avoid the story object in the test of the familiar noun. Thus, the aversion to this object that was observed in Experiment 1 was not due to its greater exposure or its being referenced immediately before testing, but to toddlers' Mutual Exclusivity bias. Their bias is hypothesized to be a form of implicit probabilistic knowledge that derives from the competitive nature of category retrieval.

The principle of mutual exclusivity as a universal constraint on word meaning by 21- to 24-month-old Korean infants.

The principle of mutual exclusivity as a universal constraint on word meaning by 21- to 24-month-old Korean infants.

Exclusion Principles for Density-Dependent Discrete Pioneer-Climax Models

The ultimate dynamical result of an undisturbed pioneer-climax model is assumed by experimental scientists to be the exclusion of the pioneer species. Examples that illustrate stable coexistence in a pioneer-climax model with no isolated positive equilibria are given. Sufficient conditions are developed and used to confirm the pioneer exclusion in discrete pioneer-climax models. Other situations are possible in such models. In particular, a mutual exclusion principle is established as a mathematical theorem.

Pioneer exclusion in a one-hump discrete pioneer-climax competitive system

One-hump maps as single species pioneer and climax ecological models confirm the expected pioneer exclusion in an uninterrupted two dimensional discrete pioneer-climax competition model. Other dynamic situations occur in such models. In particular a mutual exclusion principle is presented as a mathematical theorem.

Young Children's Disambiguation of Object Name Reference

Children show a disambiguation effect--a tendency to select unfamiliar rather than familiar things as the referents of new names. In previous studies, this effect has been reversed in young 2-year-olds, but not older children, by preexposing the unfamiliar objects, suggesting that attraction to novelty controls 2-years-olds' choices of referents for new names, but a mutual exclusivity and/or lexical gap-filling principle determines preschoolers' selections. Both the disambiguation effect and its reversal by preexposure were replicated in the present study; however, 24-month-olds' rate of selecting unfamiliar over familiar kinds was less when they were simply asked to choose between the items than when they were asked to identify the referents of unfamiliar names. Thus, some young children may have both an attraction to novel tokens and a tendency to honor an abstract lexical principle. Referent selections were also affected by object typicality and word similarity. Correlations between the tendency to acknowledge a new name's unfamiliarity and to treat it like a similar-sounding familiar name suggested that youngsters' phonological matching skills affect their interpretation of new names. Also, 4-year-olds who most often mapped distinctive-sounding new names to unfamiliar kinds tended to admit their unfamiliarity with these names most frequently, suggesting that children's increasing awareness of their own knowledge begins to affect their lexical processing during the preschool years.

The Principle of Mutual Exclusivity in Word Learning: To Honor or Not to Honor?

The Principle of Mutual Exclusivity in Word Learning: To Honor or Not to Honor?

The Principle of Mutual Exclusivity in Word Learning: To Honor or Not to Honor?

According to Markman and Wachtel, children assume that nouns pick out mutually exclusive object categories, and so each object should have only one category label. While this assumption can be useful in word learning, it is not entirely reliable. Therefore, children need to learn when to and when not to make this assumption. 6 studies examined whether knowledge about hierarchical organization of categories and about cross-language equivalents for object labels can help children limit their use of this assumption appropriately. These studies revealed that adults as well as children resisted assigning 2 novel names to the same object in some situations. By age 4, children also seemed to know enough about categorization to accept 2 names for an object if the names picked out categories from different levels of a hierarchy (e.g., animal and lemur) but not if they picked out categories from the same level (e.g., lemur and seal). Moreover, monolingual as well as bilingual children seemed to know enough about languages to accept 2 names for the same object if the names clearly came from different languages. Together, these findings suggest that even preschool children can make use of knowledge about language and categorization to fine tune the mutual exclusivity assumption in order to use it effectively in word learning.

Race, Racism and Racial Liberation

HT HE PROBLEM of twentieth century is problem of color-line relation of darker to lighter races of men in Asia and Africa, in America and islands of sea.' So wrote W. E. B. DuBois in 1903, and subsequent history has proved that he was no false prophet. Yet viewing phenomenon of race from an abstract, anthropological perspective, it is not clear why color line should be a problem. Race is a natural or anthropological category which, in itself, is devoid of political meaning. The lines of racial differentiation do not inherently define political relationships. Hence if color line is problematical, this is because a natural and therefore humanly neutral quality has been transformed into a criterion of social valuation and devaluation. And in historical fact, white skin has long been viewed as visible sign of a pure and rational soul, while conversely, black skin has been seen as mark of Cain. Consequently racial identity has served to justify domination of white masters over black slaves and, more generally, to determine one's position along a hierarchically divided political line: in American Republic, white folks have naturally lived their lives in light of Good, while black folks have spent their days in dimly lit cave. Thus in words of a no longer current Black Muslim song, the White Man's Heaven [has been] Black Man's Hell. Heaven and Hell of course locations in this world, a compartmentalized colonial or neo-colonial world in which the dividing line, frontiers, shown by barracks and police stations. The two zones thus determined are opposed, but not in service of a higher unity. Obedient to rules of pure Aristotelean logic, they both follow principle of mutual exclusivity.2 The one is inhabited by human beings, other by an anthropoid species. The colonialist describes native in zoological terms; He speaks of yellow man's reptilian motions, of stink of native quarter, of breeding swarms, of foulness, of gesticulations. When settler seeks to describe native fully in exact terms he constantly refers to bestiary.5 With such words lord of colonial creation fosters illusion of a naturally determined social differentiation between racial collectivities; and his ignoble lie becomes conscious form of political reality. The content of that form is violence. Violence is consuming fire of racism, racist ideology is its alchemical rationalization. The problem is therefore to explain peculiar process through which racial difference becomes racist domination and, by so doing, to provide a theoretical basis for practice of racial liberation.

Vibrational Spectra and Structure of Oxalyl Fluoride in the Solid and Fluid States

The vibrational spectra of oxalyl fluoride have been examined in the solid phase and re-examined in the fluid phases. From the disappearance of three major bands upon solidification, it is concluded that there must be two isomeric forms in the vapor. The spectra have been assigned on the basis of two isomers; solid-phase frequencies were used for the trans fundamentals and bands unique to the fluid states were assigned to the cis isomer. The values observed for the fundamentals in the solid are compared to those previously reported from studies of the fluid states. The internal torsion was observed at 54 cm−1 in the vapor state, and a barrier to internal rotation of 12.4 kcal/mole has been calculated. A comparison of the infrared and Raman bands in the crystal shows that the mutual exclusion principle is operative. It is concluded from this alternate forbiddance that the molecule has a centrosymmetric structure in the crystal and that each molecule occupies a Ci site. The factor group of the crystal is believed to be either C2h or D2h with two or four molecules per primitive cell.

Raman spectrum of solid glyoxal

The Raman spectrum of solid glyoxal has been recorded from 100 to 3500 cm−1. Fundamental frequencies were observed at 2882, 1729, 1364, 1078, 1050, and 551 cm−1 and assigned as the C—H stretching, C=O stretching, C—H in-plane bending, C—C stretching, C—H out-of-plane bending and COH rocking modes, respectively. The infrared spectrum of the solid has been investigated from 33 to 4000 cm−1, and the values observed for the fundamentals are compared with those previously reported from studies of the vapor. The unusual frequency shifts upon solidification are discussed. A comparison of the infrared and Raman bands in the crystal shows that the mutual exclusion principle is operative. It is concluded from this alternate forbiddance that the molecule has a centrosymmetric structure in the crystal and that each molecule occupies a C i (¯1) site. The factor group of the crystal is believed to be eitherC2h (2/m) orD2h (mmm) with two or four molecules per primitive unit cell.

Raman Spectrum and Structure of N2F4

The Raman spectra of liquid N2F4 at temperatures ranging from −80° to −150°C have been recorded. Depolarization values have been measured. The far-infrared spectrum of the vapor and solid has also been reinvestigated. Seventeen pronounced Raman lines have been observed whereas the C2 isomer of tetrafluorohydrazine has only 12 fundamentals. The large number of Raman lines suggests the presence of more than one isomer at −120°C. A comparison of the infrared and Raman bands below 800 cm− 1 shows the mutual exclusion principle is operative and it is concluded from this alternate forbiddeness that the trans-N2F4 isomer of C2h symmetry gives rise to these mutually exclusive bands. Assignment of the observed frequencies based on depolarization values, band positions, and infrared band contours are presented for the molecule in both the C2 and C2h configurations. It is shown that the data can only be interpreted in terms of an equilibrium mixture of the two isomers at both ambient and lower temperatures, and that these isomers differ little in energy.