RESUMO
Although the way tones are acquired by second or foreign language learners has attracted some scholarly attention, detailed knowledge of the factors that promote efficient learning is lacking. In this article, we look at the effect of visual cues (comparing audio-only with audio-visual presentations) and speaking style (comparing a natural speaking style with a teaching speaking style) on the perception of Mandarin tones by non-native listeners, looking both at the relative strength of these two factors and their possible interactions. Both the accuracy and reaction time of the listeners were measured in a task of tone identification. Results showed that participants in the audio-visual condition distinguished tones more accurately than participants in the audio-only condition. Interestingly, this varied as a function of speaking style, but only for stimuli from specific speakers. Additionally, some tones (notably tone 3) were recognized more quickly and accurately than others.
RESUMO
This paper investigates origins and consequences of perceived profile text originality. The first goal was to examine whether the perceived originality of authentic online dating profile texts affects online daters' perceptions of attractiveness, and whether perceptions of (less) desired partner personality traits mediate this effect. Results showed the positive impact of perceived profile text originality on impression formation: text originality positively affects perceptions of intelligence and sense of humor, which improve impressions of attractiveness and boost dating intention. The second goal was to explore what profile text features increase perceptions of profile text originality. Results revealed profile texts which were stylistically original (e.g., include metaphors) and contained more and concrete self-disclosure statements were considered more original, explaining almost half of the variance in originality scores. Taken together, our results suggest that perceived originality in profile texts is manifested in both meaning and form, and is a balancing act between novelty and appropriateness.
Assuntos
Internet , Personalidade , Envio de Mensagens de Texto , Inteligência , Percepção , IntençãoRESUMO
Speech perception is a multisensory process: what we hear can be affected by what we see. For instance, the McGurk effect occurs when auditory speech is presented in synchrony with discrepant visual information. A large number of studies have targeted the McGurk effect at the segmental level of speech (mainly consonant perception), which tends to be visually salient (lip-reading based), while the present study aims to extend the existing body of literature to the suprasegmental level, that is, investigating a McGurk effect for the identification of tones in Mandarin Chinese. Previous studies have shown that visual information does play a role in Chinese tone perception, and that the different tones correlate with variable movements of the head and neck. We constructed various tone combinations of congruent and incongruent auditory-visual materials (10 syllables with 16 tone combinations each) and presented them to native speakers of Mandarin Chinese and speakers of tone-naïve languages. In line with our previous work, we found that tone identification varies with individual tones, with tone 3 (the low-dipping tone) being the easiest one to identify, whereas tone 4 (the high-falling tone) was the most difficult one. We found that both groups of participants mainly relied on auditory input (instead of visual input), and that the auditory reliance for Chinese subjects was even stronger. The results did not show evidence for auditory-visual integration among native participants, while visual information is helpful for tone-naïve participants. However, even for this group, visual information only marginally increases the accuracy in the tone identification task, and this increase depends on the tone in question.
Assuntos
Estimulação Acústica , Idioma , Estimulação Luminosa , Percepção da Fala , Percepção do Timbre , Adulto , Povo Asiático/psicologia , Feminino , Humanos , Masculino , FonéticaRESUMO
HPLC coupled to a mass spectrometer (MS) was used for the analysis of galanthamine and lycorine in natural extracts of Leucojum aestivum and in their in vitro cultures grown with a precursor (ACC), inhibitors (AgNO(3), STS), or an absorber (KMnO(4)) of ethylene. The maximum galanthamine (0.002%) and lycorine (0.02%) concentrations in tissue cultures were obtained in the presence of KMnO(4). GCMS was used to investigate underivatized alkaloid mixtures from L. aestivum. Seven alkaloids were identified in in vivo bulbs. KMnO(4) led to the highest diversity of alkaloids in tissue culture extracts.
Assuntos
Alcaloides de Amaryllidaceae/análise , Alcaloides de Amaryllidaceae/química , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Folhas de Planta/químicaRESUMO
According to the principle of Argumentative Orientation (AO), speakers and writers adjust their frame choice to the opinion they want to convey and hearers and readers are sensitive to this profile choice. In three reaction time studies (N = 68; N = 97; N = 60) we investigated whether, in line with AO, stance-argument pairs congruent in valence are easier to process and to verify than incongruent pairs. Second, we tested whether, in line with predictions from the Markedness Principle (MP), positive congruent pairs are easier to process than negative congruent pairs. In line with AO, participants made faster and more accurate judgments of congruent pairs than of incongruent pairs. This effect was observed when controlling for word length and word frequency, and occurred irrespective of the distance between the evaluative word in the stance and argument. No unambiguous effect of Markedness was found.
Assuntos
Comportamento de Escolha/fisiologia , Cognição/fisiologia , Julgamento/fisiologia , Idioma , Adolescente , Feminino , Humanos , Masculino , Tempo de Reação , Adulto JovemRESUMO
Condensed Y chromosomes in Rumex acetosa L. root-tip nuclei were studied using 5-azaC treatment and immunohistochemical detection of methylated histones. Although Y chromosomes were decondensed within root meristem in vivo, they became condensed and heteropycnotic in roots cultured in vitro. 5-azacytidine (5-azaC) treatment of cultured roots caused transitional dispersion of their Y chromosome bodies, but 7 days after removal of the drug from the culture medium, Y heterochromatin recondensed and again became visible. The response of Rumex sex chromatin to 5-azaC was compared with that of condensed segments of pericentromeric heterochromatin in Rhoeo spathacea (Sw.) Steam roots. It was shown that Rhoeo chromocentres, composed of AT-rich constitutive heterochromatin, did not undergo decondensation after 5-azaC treatment. The Y-bodies observed within male nuclei of R. acetosa were globally enriched with H3 histone, demethylated at lysine 4 and methylated at lysine 9. This is the first report of histone tail-modification in condensed sex chromatin in plants. Our results suggest that the interphase condensation of Y chromosomes in Rumex is facultative rather than constitutive. Furthermore, the observed response of Y-bodies to 5-azaC may result indirectly from demethylation and the subsequent altered expression of unknown genes controlling tissue-specific Y-inactivation as opposed to the global demethylation of Y-chromosome DNA.
Assuntos
Cromossomos de Plantas/metabolismo , Heterocromatina/metabolismo , Rumex/citologia , Cromossomo Y/metabolismo , Azacitidina/farmacologia , Técnicas de Cultura de Células , Núcleo Celular , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Cromossomos de Plantas/efeitos dos fármacos , Cromossomos de Plantas/genética , Regulação da Expressão Gênica de Plantas , Heterocromatina/efeitos dos fármacos , Heterocromatina/genética , Histonas/metabolismo , Meristema/citologia , Metilação , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Rumex/genética , Cromossomo Y/efeitos dos fármacos , Cromossomo Y/genéticaRESUMO
This paper reports a continuation of our previous research on the phytochelatin synthase1 (PCS1) gene involved in binding and sequestration of heavy metals or metalloids in plant cells. Construction of a 3D structure of the Arabidopsis thaliana PCS1 protein and prediction of gene function by employing iterative implementation of the threading assembly refinement (I-TASSER) revealed that PC ligands (3GC-gamma-glutamylcysteine) and Gln50, Pro53, Ala54, Tyr55, Cys56, Ile102, Gly161, His162, Phe163, Asp204 and Arg211 residues are essential for formation of chelating complex with cadmium (Cd²âº) or arsenite (AsIII). This finding suggests that the PCS1 protein might be involved in the production of the enzyme phytochelatin synthase, which might in turn bind, localize, store or sequester heavy metals in plant cells. For validation of the in silico results, we included a T-DNA tagged mutant of Arabidopsis thaliana, SAIL_650_C12, (mutation in AtPCS1 gene) in our investigation. Furthermore, using reverse transcriptase PCR we confirmed that the mutant does not express the AtPCS1 gene. Mutant plants of SAIL_650_C12 were exposed to various amounts of cadmium (Cd²âº) and arsenite (AsIII) and the accumulation of these toxic metals in the plant cells was quantified spectrophotometrically. The levels of Cd²âº and AsIII accumulation in the mutant were approximately 2.8 and 1.6 times higher, respectively, than that observed in the wild-type controlled plants. We confirmed that the results obtained in in silico analyses complement those obtained in in vivo experiments.
Assuntos
Aminoaciltransferases/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Arsenitos/metabolismo , Cádmio/metabolismo , Sequência de Aminoácidos , Aminoaciltransferases/química , Aminoaciltransferases/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Arsenitos/farmacologia , Sítios de Ligação/genética , Cádmio/farmacologia , Simulação por Computador , Dipeptídeos/química , Dipeptídeos/metabolismo , Relação Dose-Resposta a Droga , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Modelos Moleculares , Dados de Sequência Molecular , Mutação , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Previously, our in silico analyses identified four candidate genes that might be involved in uptake and/or accumulation of arsenics in plants: arsenate reductase 2 (ACR2), phytochelatin synthase 1 (PCS1) and two multi-drug resistant proteins (MRP1 and MRP2) [Lund et al. (2010) J Biol Syst 18:223-224]. We also postulated that one of these four genes, ACR2, seems to play a central role in this process. To investigate further, we have constructed a 3D structure of the Arabidopsis thaliana ACR2 protein using the iterative implementation of the threading assembly refinement (I-TASSER) server. These analyses revealed that, for catalytic metabolism of arsenate, the arsenate binding-loop (AB-loop) and residues Phe-53, Phe-54, Cys-134, Cys-136, Cys-141, Cys-145, and Lys-135 are essential for reducing arsenate to arsenic intermediates (arsenylated enzyme-substrate intermediates) and arsenite in plants. Thus, functional predictions suggest that the ACR2 protein is involved in the conversion of arsenate to arsenite in plant cells. To validate the in silico results, we exposed a transfer-DNA (T-DNA)-tagged mutant of A. thaliana (mutation in the ACR2 gene) to various amounts of arsenic. Reverse transcriptase PCR revealed that the mutant exhibits significantly reduced expression of the ACR2 gene. Spectrophotometric analyses revealed that the amount of accumulated arsenic compounds in this mutant was approximately six times higher than that observed in control plants. The results obtained from in silico analyses are in complete agreement with those obtained in laboratory experiments.