Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CHARACTER”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed1992

Transmission of the hereditary S character in Drosophila simulans: effects of aging and temperature treatments.

The expression of the S character of Drosophila simulans associated to hereditary reovirus DSV is affected by the rearing temperature. The transmission of the S character and the consequences of the length of high temperature (28 degrees C) treatments on that transmission were investigated. Larvae treated at 28 degrees C from eclosion to imaginal emergence produce few S individuals in the offspring. The offspring of larvae treated between the 144th hr of development (middle of the pupal stage) and the imaginal emergence show variable levels of S phenotype expression. These levels appear to be related to the age and phenotype of their mothers. Those facts are discussed under the hypothesis of S character being caused by the hereditary reovirus Drosophila S virus.

Aging↗
PubMed1993

Brain potentials in a phonological matching task using Chinese characters.

In readers of English, involved in a rhyme judgement task, mismatch trials are associated with an enhanced N450 component of the Event Related Potentials (ERPs). It has been suggested that N450 is related to orthographic or phonological priming. In this paper ERPs were recorded during a phonological matching task, using pairs of logographically dissimilar Chinese characters. A pair was considered to match if they sounded alike with identical phoneme sequences. The subjects (native Chinese speakers) were instructed to ignore vowel-inflections, which in Chinese have lexical status. Since sublexical assembly of phonology is not used in reading Chinese characters, and the members of each pair were logographically dissimilar, match and mismatch trials did not suffer in the amount of orthographic or sublexical phonological priming. An enhanced negative component (latency near 400 msec), was observed in ERPs elicited by the second character in non-matching pairs. The negativity could be similar to N450. If this were so, then N450 could not be associated with orthographic priming, nor with sublexical phonology, but would probably be associated with postlexical processing. Also, in both readers of Chinese and English, the negativity enhanced in non-match trials is larger over the right side of the scalp, suggesting a similar brain lateralization of the underlying processes.

Adolescent↗
PubMed1986

Character displacement and niche shift analyzed using consumer-resource models of competition.

This paper analyzes the adaptive responses to competition (both character displacement and niche shift) in a two consumer-two resource model. The model includes density dependence that is unrelated to the resources that are explicit in the model. This could be due to another resource dimension, parasites, or interference competition. Competitors adapt by changing their relative consumption rate constants on the two resource types. This model can result in mutually divergent, parallel, or mutually convergent displacement of competitors. Parallel displacement may entail net divergence, net convergence, or no net change. Parallel change with net convergence is most likely when the competitors have similar constraints on the possible values of consumption rate constants, unequal allopatric abundances, and significant intraspecific density dependence. Numerical calculations of displacements are presented for several models and the effect of a number of different possible alterations of the model are discussed. The evolution of resource handling and processing efficiency, and displacement in the presence of additional selective pressures on the character are considered in detail. The results have implications for questions about maximization of population size, the relationship of character displacement and the competition coefficient, and "null" models in the study of competition. Differences between this and previous theoretical works are discussed. It is argued that conditions allowing parallel or convergent displacement are not biologically unlikely, and possible examples are discussed. Data on resource partitioning seem to be more consistent with the results reached here than with previous theory.

Animals↗
PubMed1989

Right hemisphere advantage in lexical decision with two-character Chinese words.

It has been suggested that the right hemisphere advantage reported in the literature for single Chinese or kanji characters is the result of perceptual factors rather than unique linguistic features of the orthography. However, no similar right hemisphere advantage for two-character words has ever been found. This study reports on a right hemisphere advantage for high stroke number low frequency two-character Chinese words with short exposure time and low luminance. While there is support for the perceptual-factors explanation for some findings of right hemisphere advantage for Chinese, it is suggested that linguistic factors can still play a part.

Adult↗
PubMed2006

Brain mechanism of Stroop interference effect in Chinese characters.

Event-related brain potentials were measured when 11 healthy Chinese subjects finished Chinese Characters Stroop tasks. The behavioral data showed that the Stroop task yielded a robust Stroop interference effect as indexed by longer RT for incongruent than congruent color words. Scalp ERP analysis revealed the neurophysiological substrate of the interference effect: a greater negativity in the incongruent as compared to the congruent was found between 350 and 550 ms poststimulus over midline fronto-central scalp regions. Dipole source analysis (BESA software) of the difference wave (incongruent-congruent) indicated that a generator localized in prefrontal cortex (PFC) contributed to this effect, possibly related to conflict processing and response selection. The results provided electrophysiologic evidences of the brain and cognitive mechanism of Stroop interference effect in Chinese characters and suggested that the difference between Chinese characters and English words had influence on temporal patterns of the Stroop interference effect.

Adult↗
PubMed2006

Character displacement promotes cooperation in bacterial biofilms.

Resource competition within a group of cooperators is expected to decrease selection for cooperative behavior but can also result in diversifying selection for the use of different resources, which in turn could retard the breakdown of cooperation. Diverse groups are likely to be less susceptible to invasion by noncooperating social cheats: First, competition repression resulting from character displacement may provide less of a selective advantage to cheating; second, cheats may trade off the ability to exploit cooperators that specialize in one type of resource against cooperators that specialize in another ; third, diverse communities of any kind may have higher invasion resistance because there are fewer resources available for an invader to use . Furthermore, diverse groups are likely to be more productive than clonal groups if a wider range of total resources are being used . We addressed these issues by using the cooperative trait of biofilm formation in Pseudomonas fluorescens. Character displacement through resource competition evolved within biofilms; productivity increased with increasing character displacement, and diverse biofilms were less susceptible to invasion by cheats. These results demonstrate that diversification into different ecological niches can minimize selection against cooperation in the face of local resource competition.

Biofilms↗
PubMed2006

Character changes from idiopathic cranial pachymeningoencephalitis.

A 66-year-old man with idiopathic cranial pachymeningoencephalitis was described. He suffered from left orbital pain, and character changes. He became short tempered, and was very attached to trifles. Two years prior to these symptoms, he had developed transient left abducent nerve palsy. Head MRI showed a thickening and enhancement of the dura mater on gadolinium-enhanced T1-weighted images, and high signal intensity lesions at bilateral frontal lobes predominantly in the white matter on T2-weighted images. Biopsies revealed microglial proliferation in the cerebral parenchyma, and mild lymphocytic perivascular infiltration. No evidence of intracranial infection was detected. We therefore treated him with methylprednisolone pulse therapy followed by oral prednisolone. His character became gradually normalized, and bilateral frontal lobe lesions seen on MRI disappeared. This is the first case to describe recurrent pachymeningoencephalitis with character changes, and symptoms were probably due to frontal lobe dysfunction.

Abducens Nerve Diseases↗
PubMed2004

Bayesian inference of character evolution.

Much recent progress in evolutionary biology is based on the inference of ancestral states and past transformations in important traits on phylogenetic trees. These exercises often assume that the tree is known without error and that ancestral states and character change can be mapped onto it exactly. In reality, there is often considerable uncertainty about both the tree and the character mapping. Recently introduced Bayesian statistical methods enable the study of character evolution while simultaneously accounting for both phylogenetic and mapping uncertainty, adding much needed credibility to the reconstruction of evolutionary history.

Journal Article↗
PubMed2004

Molecular phylogeny of Demospongiae: implications for classification and scenarios of character evolution.

An analysis of the phylogenetic relationships of the 13 orders of Demospongiae, based on 18S and C1, D1 and C2 domains of 28S rRNA (for, respectively, 26 and 32 taxa) has been performed. The class Demospongiae as traditionally defined is not found to be monophyletic. Instead, a clade comprising all demosponges except Homoscleromorpha is well-supported, and we define phylogenetically the name Demospongiae in this more restricted sense to preclude the possibility of drastic alterations of the meaning of Demospongiae in the future, depending on the position of Homoscleromorpha. Within this clade Demospongiae s.s., ceractinomorphs and tetractinomorphs are polyphyletic, implying homoplastic evolution of characters such as reproductive strategies (viviparity vs. oviparity) and skeleton architecture (reticulate vs. radiate). The topology derived from our molecular data provides a basis for proposing a new classification of Demospongiae s.s., and suggests a reverse polarity of some characters, with respect to traditional conceptions: viviparity, presence of monaxon spicules and of spongin appear to be ancestral, whereas oviparity, and presence of tetraxon spicules appear as derived characters.

Animals↗
PubMed2006

Phylogenetic significance of morphological characters in the tropical Hypotrachyna clade of parmelioid lichens (Parmeliaceae, Ascomycota).

Lichen-forming ascomycetes exhibit often complex morphologies of the vegetative thallus that are usually not found in non-lichenized fungi. This includes the thallus organization and appendical structures associated with the main thallus, such as cilia and rhizines. Such morphological characters are widely employed in the taxonomy of parmelioid lichens, especially at generic level. Within parmelioid lichens, several monophyletic groups can be distinguished, the Hypotrachyna clade being one of them, which includes mostly tropical taxa. In this first molecular study focused specifically on the Hypotrachyna clade, we used maximum parsimony and Bayesian analyses of a combined data set of nuclear ITS and mitochondrial SSU rDNA sequences to (1) test the monophyly of genera presently accepted within the clade and (2) evaluate the phylogenetic value of the morphological characters used to circumscribe genera in parmelioid lichens. Out of the 89 mtSSU and 88 nuITS sequences included in the present study, 121 sequences were newly obtained. Our results show that the taxa within the clade fall into two major groups and that the genus Hypotrachyna is polyphyletic. Everniastrum and Parmelinopsis are nested within Hypotrachyna sensu stricto, the latter being also polyphyletic. Bulbothrix is paraphyletic with Parmelinella nested within and is basal to the second major Hypotrachyna clade. Monophylies of Bulbothrix and Hypotrachyna are significantly rejected. The phylogenetic analysis demonstrates that morphological characters currently used to circumscribe genera in parmelioid lichens, such as cortical anatomy, lobe configuration, cilia, and rhizines have been overestimated and have only minor value in identifying monophyletic groups.

Lichens↗
PubMed2000

A comparison of Bulinus africanus group species (Planorbidae; Gastropoda) by use of the internal transcribed spacer 1 region combined by morphological and anatomical characters.

The morphological and anatomical characters applied to determine species identity in the Bulinus africanus group species are insufficient to unambiguously discriminate between arbitrary species of given populations. In order to solve this problem, four snail populations from Kenya have been investigated morphologically and anatomically, and the species status compared with the result of molecular methods. We have amplified the entire ITS region and found that the investigated populations showed intra-specific genetic polymorphism, thereby giving the taxa an identity which were indistinct when the region was cut with restriction enzymes. Instead, an amplification of the sub-region ITS 1 revealed an unambiguous identification. because the amplification revealed only one single fragment. We also found that the observed heterogeneity of the entire ITS region could be confined to the sub-region ITS 2. Furthermore, the micro-sculpture of the shell and penis to preputium proportion, which are normally applied as morphological characters, might be considered as inadequate, because of the lack of a significant difference in those characters between the two well established species, namely B. africanus and B. nasutus in the Kisumu area. Instead, these two taxa were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to be one single species with a highly variable morphology. This result was further confirmed by random amplified polymorphic DNA (RAPD) data and the mitochondrial cytochome oxidase subunit I (COI).

Animals↗
PubMedDate not supplied

Swedish normative data on personality using the Temperament and Character Inventory.

The Temperament and Character Inventory (TCI) is a self-report personality questionnaire based on Cloninger's psychobiological model of personality, which accounts for both normal and abnormal variation in the two major components of personality, temperament and character. Normative data for the Swedish TCI based on a representative Swedish sample of 1,300 adults are presented, and the psychometric properties of the questionnaire are discussed. The structure of the Swedish version replicates the American version well for the means, distribution of scores, and relationships within the between scales and subscales. Further, the Swedish inventory had a reliable factor structure and test-retest performance. The results of this study confirm the theory of temperament and character as a seven-factor model of personality.

Adult↗
PubMed1985

Use of keyed character string data structures and operators in models of primate groups.

Many primate populations exhibit forms of organization that are both complex and highly dynamic. A prototype of a general purpose primate population computer modelling system has been developed; this modelling system provides data structures and operators that facilitate computer representation of many static and dynamic features of primate population organization. In this system, primate group structures are represented by text strings known as key strings. A key string begins with a label or key character that identifies its population element type. The label character is followed by data fields contained between bounds marker characters. Nested key strings can be used to concisely represent many of the structural features of social groups in different primate species. Changes in group structures are accomplished by key string insertion, deletion and move operations. Models of structures and processes in island, rhesus monkey and hamadryas baboon populations built with this prototype modelling system are discussed. In these pilot applications, use of key string data structures and operators greatly simplifies many aspects of model construction.

Animals↗
PubMed1998

The effect of complexity upon hemispheric specialization for reading Chinese characters.

A number of reports in the literature have suggested that there is a right hemisphere advantage for the processing of single Chinese or Japanese characters. There are, nonetheless, many studies which have produced contradictory findings, suggesting that the factor or factors underlying the lateral asymmetry have not been clearly identified. The present study investigated the proposal that visual complexity of single Chinese characters, as measured by stroke number, was related to a right hemisphere advantage for processing this material. However, increasing the level of complexity of the characters was found to be related to the development of a left hemisphere advantage, thus clearly disconfirming the proposal. It is argued that the results are more satisfactorily interpreted in terms of the relationship between hemisphere specialization and the spatial frequency of the stimuli.

Adult↗
PubMed2002

Influence of the character of NOM on the ozonation of MIB and geosmin.

Tastes and odours (T&Os) are a major concern in drinking water as they are not efficiently removed by conventional water treatment. Ozonation has been effective for their destruction in some studies. However, the natural organic matter (NOM) in waters can affect the ozonation process and subsequently affect the destruction of T&Os. Five NOM fractions were isolated and ozonated in synthetic waters. The fraction containing the more highly coloured, higher molecular weight compounds exhibited the highest ozone (O3) demand, whereas the low aromatic fraction exhibited the lowest O3 demand. The character of the NOM fractions influenced the ozonation of MIB and geosmin. The destruction of MIB and geosmin was significantly higher in the fraction with the highest colour and UV/visible absorbance at all O3 doses. The destruction of the compounds in the other fractions showed the same trends, increasing MIB and geosmin destruction with increasing UV/visible absorbing character of the NOM. MIB was also ozonated in two real waters. with results showing a competing effect between NOM concentration and NOM character. The O3 reaction time was shown to be important for the destruction of both compounds.

Camphanes↗
PubMed2001

Visual language and handwriting movement: functional magnetic resonance imaging at 3 tesla during generation of ideographic characters.

A functional magnetic resonance imaging experiment at 3 tesla was performed to investigate the collaborative mechanism between visuospatial processing and motor execution in performing visual language generation tasks. Japanese Kanji, ideographic characters, were utilized to design tasks. The bilateral border portions between the inferior parietal lobule and the occipital lobe were involved during a Kanji puzzle task, which required subjects to combine several parts into a Kanji. The higher motor areas, such as the premotor areas and the pre-supplementary motor areas, were also activated bilaterally during the puzzle task. The parieto-occipital activation may be related to analysis of configuration or segmentation/integration of Kanji figures. Activation in the higher motor areas may be induced by cognitive components related to motor function to perform the visuospatial language task, such as intense reference for displayed characters and finding a proper character for puzzle solution. A collaborative mechanism in these areas may explain the effectiveness of tactile reading in letter recognition by patients with pure alexia or kinesthetic facilitation by Kanji users when recalling difficult Kanji.

Adult↗
PubMed2002

Qualitative character and sensory representation.

Perceptual experience seems to involve distinct intentional and qualitative features. Inasmuch as one can visually perceive that there is a Coke can in front of one, perceptual experience must be intentional. But such experiences seem to differ from paradigmatic intentional states in having introspectible qualitative character. argues that a perceptual experience's qualitative character is determined by intrinsic, nonrepresentational properties. But also argues that perceptual experiences have nonconceptual representational content in addition to conceptual content and nonrepresentational sensational properties. He thus distinguishes between conceptual, nonrepresentational, and nonconceptual but representational aspects of perceptual experience. I will argue that Peacocke posits too much. Contrary to his (1983) arguments, the sensational properties Peacocke claims are nonrepresentational are best construed as representational; they are best explained in terms of their relation to the perceptible properties they enable us to perceive. Since sensational properties are arguably nonconceptual, they are best construed as nonconceptual representational properties. I offer the Homomorphism View of sensory qualities, pioneered by, as a unified account of qualitative character and nonconceptual sensory representation. According to this view, a sensory quality represents a perceptible stimulus property in virtue of resembling and differing from other sensory qualities in ways parallel to the ways the stimulus property resembles and differs from other perceptible properties.

Environment↗
PubMed2002

Phylogeny of Tunicata inferred from molecular and morphological characters.

The phylogeny of the Tunicata was reconstructed using molecular and morphological characters. Mitochondrial cytochrome oxidase I (cox1) and 18S rDNA sequences were obtained for 14 and 4 tunicate species, respectively. 18S rDNA sequences were aligned with gene sequences obtained from GenBank of 57 tunicates, a cephalochordate, and a selachian craniate. Cox1 sequences were aligned with the sequence of two ascidians and a cephalochordate obtained from GenBank. Traditional, morphological, life history, and biochemical characters of larval and adult stages were compiled from the literature and analyzed cladistically. Separate and simultaneous parsimony analyses of molecular and morphological data were carried out. Aplousobranch ascidians from three different families were included in a molecular phylogenetic analysis for the first time. Analysis of the morphological, life history, and biochemical characters results in a highly unresolved tree. Aplousobranchiata form a strongly supported monophylum in the analysis of the 18S rDNA data, the morphological data, and the combined data set. Cionidae is not included in the Aplousobranchiata but nests within the Phlebobranchiata. Appendicularia (=Larvacea) nest within the 'Ascidiacea' as the sister taxon of Aplousobranchiata in the parsimony analysis of the 18S rDNA data and the combined analysis. A potential morphological synapomorphy of Aplousobranchiata plus Appendicularia is the horizontal orientation of the larval tail. In the 18S rDNA and the combined analysis, Thaliacea is included in the 'Ascidiacea' as the sister group to Phlebobranchiata. Pyrosomatida is found to be the sister taxon to the Salpidae in analyses of 18S rDNA and combined data, whereas the analysis of the morphological data recovers a sister group relationship between Doliolidae and Salpidae. Results of cox1 analyses are incongruent with both the 18S rDNA and the morphological phylogenies. Cox1 sequences may evolve too rapidly to resolve relationships of higher tunicate taxa. However, the cox1 data may be useful at lower taxonomic levels.

Animals↗