首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A well-known phenomenon in Swedish is that some adjectives are ‘defective’ in the sense that they are not possible in neuter gender. In previous explanations, it has usually been argued that the defective forms could be distinguished from non-defective forms by phonological and/or semantic criteria. Showing that such proposals cannot account for the data, I will argue that the defective paradigms are caused by a number of phonological constraints which block morphological productivity not only in defective forms, but also in many nondefective forms. Thus, contrary to what has traditionally been assumed, common patterns of vowel shortening and dental assimilation in Swedish adjective paradigms are not the result of productivity, but the result of a type of creative generalization where new formations require a sufficient degree of communicative need in order to be perceived as grammatical.  相似文献   

2.
Hannah Sande 《Morphology》2018,28(3):253-295
This paper presents data bearing on two key issues in morphophonological theory: 1) the domain of phonological evaluation, and 2) the item- versus process-morphology debate. I present data from Guébie (Kru) [Côte d’Ivoire] showing that imperfective aspect is exponed by a scalar shift in surface tone, which can affect either the tone of the inflected verb, or the subject noun phrase. There are four tone heights in Guébie, and the first syllable of a verb can underlyingly be associated with any of the four tones. In imperfective contexts only, that initial verb tone lowers one step on the four-tone scale. If the tone of the verb is already low, the final tone of the subject raises one step instead. This paper demonstrates that in order to account for the cross-word tonal effects of the imperfective morpheme, phonological evaluation must scope over more than one word at a time; specifically, it must scope over a syntactic phase. Additionally, I show that with phonological constraint rankings sensitive to morphosyntactic construction, no abstract phonological underlying form of the imperfective morpheme is necessary.  相似文献   

3.
This study examines allomorphy in vowel selection in Hebrew. We address the formation of adjectives and passive verbs in a specific morphological pattern with stem-medial glottals. While the normative vowel that precedes the glottal is o, there are cases where it is colloquially u. We provide empirical evidence for this variation (or lack thereof), arguing that vowel selection results from the distinction between adjectives and passive verbs and, more generally, from the component of the grammar where they are derived, the lexicon and the syntax. Studies of Hebrew have shown that a has a more morphological-lexical status, as it is typical of word formation processes, while e has a phonological status as it is the default vowel in epenthesis. A previous study has also shown that a is more typical of the lexicon and e is more typical of the syntax. We propose a similar distinction between o and u; u tends to be selected in passive formation in the syntax, while o is selected for words stored in the lexicon. In addition, we claim that the occurrence of each allomorph is triggered by uniformity to other forms in different paradigms that are taken into account in word formation. The study provides further evidence to a new type of allomorphy, whose evidence for conditioning is not purely phonological or morpho-syntactic, but rather depends on the locus of word formation. It highlights the strong correlation between form, meaning and the relevant grammatical component in word formation.  相似文献   

4.
Word formation in Arabic has traditionally been assumed to involve interdigitation of a consonantal root with a vocalic pattern. This view is adopted by a large number of modern generative morphologists. More recently, however, several morphologists have argued that words in Semitic are formed from fully vocalised stems. In this paper, I argue that in San'ani (the dialect of San'a), and in some other Arabic dialects, there is a class of verbs that have as part of either their denotations or connotations a diminutive sense. I then consider diminutive nouns in the dialect. On the basis of semantic and phonological relationships between diminutive verbs and their non-diminutive counterparts, as well as native speakers' explanations of certain diminutive verbs, and the relationship between diminutive nouns and their non-diminutive counterparts, I argue that while some derivational processes take the root as the basic morphological unit, phonological and semantic similarities between certain stems can only be accounted for by derivation from a fully vocalised stem. I therefore conclude that both root-based and stem-based types of word formation occur.  相似文献   

5.
One of the major benefits of interdisciplinary research is the chance to swap tools between fields, to save having to reinvent the wheel. The fields of language evolution and evolutionary biology have been swapping tools for centuries to the enrichment of both. Here I will discuss three categories of tool swapping: (1) conceptual tools, where analogies are drawn between hypotheses, patterns or processes, so that one field can take advantage of the path cut through the intellectual jungle by the other; (2) theoretical tools, where the machinery developed to process the data in one field is adapted to be applied to the data of the other; and (3) analytical tools, where common problems encountered in both fields can be solved using useful tricks developed by one or the other. I will argue that conceptual tools borrowed from linguistics contributed to the Darwinian revolution in biology; that theoretical tools of evolutionary change can in some cases be applied to both genetic and linguistic data without having to assume the underlying evolutionary processes are exactly the same; and that there are practical problems that have long been recognised in historical linguistics that may be solved by borrowing some useful analytical tools from evolutionary biology.  相似文献   

6.
Nasality is a very important characteristic of several languages, European Portuguese being one of them. This paper addresses the challenge of nasality detection in surface electromyography (EMG) based speech interfaces. We explore the existence of useful information about the velum movement and also assess if muscles deeper down in the face and neck region can be measured using surface electrodes, and the best electrode location to do so. The procedure we adopted uses Real-Time Magnetic Resonance Imaging (RT-MRI), collected from a set of speakers, providing a method to interpret EMG data. By ensuring compatible data recording conditions, and proper time alignment between the EMG and the RT-MRI data, we are able to accurately estimate the time when the velum moves and the type of movement when a nasal vowel occurs. The combination of these two sources revealed interesting and distinct characteristics in the EMG signal when a nasal vowel is uttered, which motivated a classification experiment. Overall results of this experiment provide evidence that it is possible to detect velum movement using sensors positioned below the ear, between mastoid process and the mandible, in the upper neck region. In a frame-based classification scenario, error rates as low as 32.5% for all speakers and 23.4% for the best speaker have been achieved, for nasal vowel detection. This outcome stands as an encouraging result, fostering the grounds for deeper exploration of the proposed approach as a promising route to the development of an EMG-based speech interface for languages with strong nasal characteristics.  相似文献   

7.
Three approaches to the neuropsychology of cognitive function are distinguished: the neuroanatomical (where the primary concern is to correlate particular disorders of cognitive function with particular lesion sites), the 'general-cognitive' (in which associations are sought between impairments of performance on specific cognitive tasks and general disorders of broadly defined cognitive processes) and the model-building (in which one attempts to interpret the pattern of impairments and preservations of some cognitive function produced by brain damage in terms of an explicit model of the normal operation of this function). I claim that the model-building approach to the neuropsychology of cognitive function must take precedence over the other two. One reason for this is that any disorder of cognitive function can only be defined with reference to some model of that function. I illustrate this claim with reference to acquired disorders of reading, describing current work of a psycholinguistic nature dealing with two acquired disorders of reading: phonological dyslexia and surface dyslexia. A psycholinguistic account of normal reading is used as a theoretical framework to define and to explain the patterns of deficit and preservation observed in these two dyslexias. The detailed account of surface dyslexia in English provided by this framework is then used to make predictions about the nature of surface dyslexia in other languages: alphabetically written languages where all words are regularly spelled, or where homophones cannot occur, as well as ideographically and syllabically written languages. A case of surface dyslexia in an English-Spanish bilingual, in which such predictions were confirmed, is described.  相似文献   

8.
Azadpour M  Balaban E 《PloS one》2008,3(4):e1966
Neuroimaging studies of speech processing increasingly rely on artificial speech-like sounds whose perceptual status as speech or non-speech is assigned by simple subjective judgments; brain activation patterns are interpreted according to these status assignments. The naïve perceptual status of one such stimulus, spectrally-rotated speech (not consciously perceived as speech by naïve subjects), was evaluated in discrimination and forced identification experiments. Discrimination of variation in spectrally-rotated syllables in one group of naïve subjects was strongly related to the pattern of similarities in phonological identification of the same stimuli provided by a second, independent group of naïve subjects, suggesting either that (1) naïve rotated syllable perception involves phonetic-like processing, or (2) that perception is solely based on physical acoustic similarity, and similar sounds are provided with similar phonetic identities. Analysis of acoustic (Euclidean distances of center frequency values of formants) and phonetic similarities in the perception of the vowel portions of the rotated syllables revealed that discrimination was significantly and independently influenced by both acoustic and phonological information. We conclude that simple subjective assessments of artificial speech-like sounds can be misleading, as perception of such sounds may initially and unconsciously utilize speech-like, phonological processing.  相似文献   

9.
MOTIVATION: Biological samples frequently contain multiple cell-types that each can play a crucial role in the development and/or regulation of adjacent cells or tissues. The search for biomarkers, or expression patterns of, one cell-type in those samples can be a complex and time-consuming process. Ordinarily, extensive laboratory bench work must be performed to separate the mixed cell population into its subcomponents, such that each can be accurately characterized. RESULTS: We have developed a methodology to electronically subtract gene expression in one or more components of a mixed cell population from a mixture, to reveal the expression patterns of other minor or difficult to isolate components. Examination of simulated data indicates that this procedure can reliably determine the expression patterns in cell-types that contribute as little as 5% of the total expression in a mixed cell population. We re-analyzed microarray expression data from the viral infection of macrophages and from the T-cells of wild type and Foxp3 deletion mice. Using our subtraction methodology, we were able to substantially improve the identification of genes involved in processes of subcomponent portions of these samples.  相似文献   

10.
On the basis of data from the synthetic and agglutinative South American language Wichi (Mataguayan, Argentina/Bolivia), I argue in favor of regarding interface phenomena as typological variables. In particular, in this paper I discuss what type of interactions these are, arguing that they do not affect wordhood but do contribute to its formation. I will defend the hypothesis that linguistic level interactions within the word are of two types and different in nature: overlapping on the one hand and conditioning and alteration on the other. Conditioning only takes place in morphophonological and morphosemantic interactions and it follows the wordhood requirements of the language. Conversely, the interaction of morphology with all linguistic levels shows overlapping of units: the phonological word and the grammatical word in the morphophonological relation; the word and the simple clause or nominal phrase in the morphosyntactic relation; and the word and the semantic unit in the morphosemantic relation. This explains why the word is generally defined by phonological, morphological, syntactic and semantic criteria. It is to be hoped that the conclusions arrived at in this paper would contribute to deepen our knowledge of the notion of wordhood in synthetic languages in South America as well as our understanding of language structure and functioning.  相似文献   

11.
Clonal deletion is the major mechanism by which T cell tolerance is achieved in vivo. The process of activation-driven cell death, originally characterized with T cell hybridomas, likely represents the mechanism of clonal deletion because it shares a number of properties with the in vivo process, especially the ability to be triggered in an Ag-specific manner, the cell-autonomous nature of the response, and its sensitivity to the drug cyclosporin A. We now have extended our analysis of activation-driven cell death to clonal populations of nontransformed T cells. Activation-driven cell death can be induced in nontransformed T lymphocytes by combinations of mitogenic stimuli. In particular, two mitogenic stimuli at high dose, one a lymphokine and the other delivered via the TCR or another activation structure, are required to induce activation-driven cell death. Activation-driven cell death is an active cell suicide process with attributes typical of physiological cell death, including early nuclear disintegration and a requirement for macromolecular synthesis, and is distinct from death by factor deprivation. Susceptibility to the induction of cell death by antigenic or activating stimulation is a common aspect of most T cells and is consistent with observations that clonal deletion can occur throughout T cell ontogeny. Most importantly, the alternative cellular responses of cell death and cell proliferation in nontransformed T cells appear to be triggered solely as a function of quantitative differences in the doses of identical stimuli. This can be viewed as a dose-dependent switch that determines cell fate. Developmental regulation of this switch may explain the processes of positive and negative selection during T cell ontogeny and also provide a mechanistic rationale for a strategy of selective anti-tumor therapy.  相似文献   

12.
Blackawton bees     
BACKGROUND: Real science has the potential to not only amaze, but also transform the way one thinks of the world and oneself. This is because the process of science is little different from the deeply resonant, natural processes of play. Play enables humans (and other mammals) to discover (and create) relationships and patterns. When one adds rules to play, a game is created. THIS IS SCIENCE: the process of playing with rules that enables one to reveal previously unseen patterns of relationships that extend our collective understanding of nature and human nature. When thought of in this way, science education becomes a more enlightened and intuitive process of asking questions and devising games to address those questions. But, because the outcome of all game-playing is unpredictable, supporting this 'messyness', which is the engine of science, is critical to good science education (and indeed creative education generally). Indeed, we have learned that doing 'real' science in public spaces can stimulate tremendous interest in children and adults in understanding the processes by which we make sense of the world. The present study (on the vision of bumble-bees) goes even further, since it was not only performed outside my laboratory (in a Norman church in the southwest of England), but the 'games' were themselves devised in collaboration with 25 8- to 10-year-old children. They asked the questions, hypothesized the answers, designed the games (in other words, the experiments) to test these hypotheses and analysed the data. They also drew the figures (in coloured pencil) and wrote the paper. Their headteacher (Dave Strudwick) and I devised the educational programme (we call 'i,scientist'), and I trained the bees and transcribed the childrens' words into text (which was done with smaller groups of children at the school's local village pub). So what follows is a novel study (scientifically and conceptually) in 'kids speak' without references to past literature, which is a challenge. Although the historical context of any study is of course important, including references in this instance would be disingenuous for two reasons. First, given the way scientific data are naturally reported, the relevant information is simply inaccessible to the literate ability of 8- to 10-year-old children, and second, the true motivation for any scientific study (at least one of integrity) is one's own curiousity, which for the children was not inspired by the scientific literature, but their own observations of the world. This lack of historical, scientific context does not diminish the resulting data, scientific methodology or merit of the discovery for the scientific and 'non-scientific' audience. On the contrary, it reveals science in its truest (most naive) form, and in this way makes explicit the commonality between science, art and indeed all creative activities. PRINCIPAL FINDING: 'We discovered that bumble-bees can use a combination of colour and spatial relationships in deciding which colour of flower to forage from. We also discovered that science is cool and fun because you get to do stuff that no one has ever done before. (Children from Blackawton)'.  相似文献   

13.
Four experiments sought evidence that listeners can use coherent changes in the frequency or amplitude of harmonics to segregate concurrent vowels. Segregation was not helped by giving the harmonics of competing vowels different patterns of frequency or amplitude modulation. However, modulating the frequencies of the components of one vowel was beneficial when the other vowel was not modulated, provided that both vowels were composed of components placed randomly in frequency. In addition, staggering the onsets of the two vowels, so that the amplitude of one vowel increased abruptly while the amplitude of the other was stationary, was also beneficial. Thus, the results demonstrate that listeners can group changing harmonics and can segregate them from stationary harmonics, but cannot use coherence of change to separate two sets of changing harmonics.  相似文献   

14.
Inferring speciation rates from phylogenies   总被引:6,自引:0,他引:6  
Abstract It is possible to estimate the rate of diversification of clades from phylogenies with a temporal dimension. First, I present several methods for constructing confidence intervals for the speciation rate under the simple assumption of a pure birth process. I discuss the relationships among these methods in the hope of clarifying some fundamental theory in this area. Their performances are compared in a simulation study and one is recommended for use as a result. A variety of other questions that may, in fact, be the questions of primary interest (e.g., Has the rate of cladogenesis been declining?) are then recast as biological variants of the purely statistical question—Is the birth process model appropriate for my data? Seen in this way, a preexisting arsenal of statistical techniques is opened up for use in this area: in particular, techniques developed for the analysis of Poisson processes and the analysis of survival data. These two approaches start from different representations of the data—the branch lengths in the tree—and I explicitly relate the two. Aiming for a synoptic account of useful theory in this area, I briefly discuss some important results from the analysis of two distinct birth‐death processes: the one introduced into this area by Hey (1992) is refitted with some powerful statistical tools.  相似文献   

15.
Null community is a spatio‐temporal abstraction of an initial regional species pool from which local species pools and actual community assemblages are organized. Any process that causes joint responses of species with similar susceptibilities affects community assembly. Through time, sequential assembly processes change the composition of a species pool in a way analogous to the one in which evolutionary processes promote character changes from an ancestor to current species. The segregation of species occurrences in an actual community suggests that assembly processes non‐randomly structured the observed community assemblages. However, going backwards to imply the causes of a particular arrangement of species is a non‐trivial challenge. I merge these premises with the philosophical and methodological foundations of cladistics. I propound parsimony analysis of species co‐occurrences as an outstanding means of devising operational hypotheses about the assembly of any non‐randomly structured set of actual community assemblages related to a common species pool. To explore this approach, I used field data gathered in a suite of 10 wetland assemblages. First, I tested independence of 101 plant species occurrences by a null model. As significant non‐random species co‐occurrence was detected, I applied a parsimony analysis taking the species occurrences as attributes, the assemblages as terminal units, and a putative null community constituted by all the present local species as the root of the assembly suite. The analysis produced four most parsimonious trees of assembly relationships. These trees maximize the number of similarities among community assemblages that can be explained by the sole fact of sharing a common regional species pool. One most parsimonious spatio‐temporal arrangement of species occurrence changes was reconstructed on one of the trees. I interpret this reconstruction in terms of assembly events, species exclusions and recruitments, showing the potentialities of this analysis to formulate operational hypotheses about community organization.  相似文献   

16.
Cho K  Ryu K  Lee E  Won S  Kim J  Yoo OJ  Hahn S 《Molecules and cells》2001,11(1):21-27
The goal of this study was to define the correlation between genotype and phenotype in Korean patients with spinal muscular atrophy (SMA). The SMA can be classified into three groups based on the age of onset and the clinical course. The candidate genes, survival motor neuron (SMN) gene, neuronal apoptosis inhibitory protein (NAIP) gene, and p44 gene were mapped and duplicated with telomeric and centromeric. The loss of the telomeric SMN occurs by a different mechanism. That is the deletion or conversion of telomeric SMN to centromeric SMN, in which case the conversion could produce a mild phenotype and deletion could produce a severe one. It has been known that there may be a balance between the numbers of copies expressed by the centromeric and telomeric SMN genes. In our study, ten patients with type I SMA and two type II patients were identified by their clinical findings and DNA studies. The major deletion of SMA candidate genes, deletion of the SMN gene, NAIP gene, and p44 gene were identified in six patients with type I SMA, while the rest of type I and all the type II patients showed the deletion of the SMN gene only. Allele numbers of the C212 marker were compared in patients and normal controls in order to find the correlation between the copy numbers and the clinical severity. The result was that type I patients had 2-5 alleles and the normal controls had 4-6. This suggests that the deletion is a major determining factor in the clinical phenotype. However, two type I patients with telomeric NAIP gene deletion notably had 4-5 alleles, as in the normal controls. This result implies that the correlation between the copy numbers and the severity is uncertain as opposed to the previous hypothesis. One type I patient showed the conversion of the centromeric SMN gene to the telomeric, which supports the conclusion that gene conversion is an important molecular mechanism for SMA. In the study of one hundred normal newborns, two physically normal newborns showed deletion of the centromeric SMN gene, suggesting frequent rearrangement in the locus.  相似文献   

17.
The Notch signalling pathway has a central role in a wide variety of developmental processes and it is not therefore surprising that mutations in components of this pathway can cause dramatic human genetic disorders. One developmental process in which the Notch pathway is involved at multiple levels is somitogenesis, the mechanism by which the embryo is divided into segments that ultimately form structures such as the axial skeleton and skeletal muscle of the trunk. We are investigating the human genetic disorder spondylocostal dysplasia (SCD), which is a group of malsegmentation syndromes that occur when this process is disrupted. Mutations in the Notch ligand DELTA-LIKE 3 (DLL3) are responsible for cases of autosomal recessive SCD type I (SCDO1), and we are using information derived from these mutations to study the structure of the DLL3 protein. To aid in elucidation of the underlying developmental defect in SCDO1, we have generated a mouse model by targeted deletion of the Dll3 gene (Dunwoodie et al., 2002). These mice show segmentation defects similar to those seen in SCDO1. In addition, these mice have a distinct set of neural defects that may be useful in future neurological assessment of affected individuals. Finally, since not all cases of SCD are due to mutation of DLL3, we are investigating various genes to find other candidates involved in this genetic disease.  相似文献   

18.
The role of learning in the development of bird vocalizations other than territorial song is not well studied. The well-known role of direct imitation in the development of territorial song potentially masks the effects of other processes in the development of vocal behaviour. The ‘chick-a-dee’ call of black-capped chickadees is a good system in which to investigate more subtle developmental processes because this call is composed of a small number of distinctive note types. These note types may be classified objectively based on a simple set of acoustic variables, allowing for a quantitative assessment of vocal learning. We raised four groups of black-capped chickadees under different degrees of social and acoustic isolation. We then used a multivariate analysis of the acoustic structure of the introductory call notes (‘A-’ ‘B-’ and ‘C-notes’) to determine how similar the notes produced by these hand-reared birds were to the notes of wild birds. Hand-reared chickadees with greater exposure to normal phonology produced notes of all three note types that were more similar to those of wild birds. Regardless of experience, however, all birds produced A-notes that fell within the normal range of those produced by wild birds. By contrast, the development of normal B- and C-notes appears to be more dependent upon experience. These data suggest that learning may play a different role in the development of different phonological units within one vocalization. Our results also illustrate the importance of considering processes other than simple imitation in the development of avian vocalizations.  相似文献   

19.
German linking elements are sometimes classified as inflectional affixes, sometimes as derivational affixes, and in any case as morphological units with at least seven realisations (e.g. -s-, -es-, -(e)n-, -e-). This article seeks to show that linking elements are hybrid elements situated between morphology and phonology. On the one hand, they have a clear morphological status since they occur only within compounds (and before a very small set of suffixes) and support the listener in decoding them. On the other hand, they also have to be analysed on the phonological level, as will be shown in this article. Thus, they are marginal morphological units on the pathway to phonology (including prosodics). Although some alloforms can sometimes be considered former inflectional endings and in some cases even continue to demonstrate some inflectional behaviour (such as relatedness to gender and inflection class), they are on their way to becoming markers of ill-formed phonological words. In fact, linking elements, above all the linking -s-, which is extremely productive, help the listener decode compounds containing a bad phonological word as their first constituent, such as Geburt+s+tag ‘birthday’ or Religion+s+unterricht ‘religious education’. By marking the end of a first constituent that differs from an unmarked monopedal phonological word, the linking element aids the listener in correctly decoding and analysing the compound. German compounds are known for their length and complexity, both of which have increased over time—along with the occurrence of linking elements, especially -s-. Thus, a profound instance of language change can be observed in contemporary German, one indicating its typological shift from syllable language to word language.  相似文献   

20.
G Ju  L Boone  A M Skalka 《Journal of virology》1980,33(3):1026-1033
Unintegrated proviral DNA of Schmidt-Ruppin B Rous sarcoma virus was cloned in the bacteriophage lambda vector Charon 21A. A total of 12 independent recombinant lambda SRBtd clones which were derived from the transformation-defective component in the viral preparation were analyzed with restriction endonucleases and molecular hybridization techniques. Three classes of clones were observed. Type I clones contained a 5.0-megadalton insert of viral DNA, type II clones contained phage with two size classes of inserts (5.0 and 5.2 megadaltons), and one type III clone contained only a 5.2-megadalton insert. The smaller insert present in type II clones appeared to be derived by deletion of one copy of a directly repeated sequence which was present in the larger insert. Mapping data indicated that the deletion includes all or part of the terminal repeat found in linear double-stranded proviral DNA. Similar results were obtained from lambda RAV2 recombinant clones derived from Rous-associated virus type 2. Analysis of DNA from type II and type III clones of lambda SRBtd and lambda RAV2 revealed limited heterogeneity in the size of the direct repeat.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号