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1.
Phys Rev Lett ; 131(16): 161802, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37925710

RESUMO

We present a new measurement of the positive muon magnetic anomaly, a_{µ}≡(g_{µ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{µ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{µ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{µ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.

2.
Phys Rev Lett ; 126(14): 141801, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33891447

RESUMO

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{µ}≡(g_{µ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{µ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both µ^{+} and µ^{-}, the new experimental average of a_{µ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

3.
Int Ophthalmol ; 37(6): 1311-1317, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27990622

RESUMO

PURPOSE: To compare the refractive outcome of eyes that underwent phacoemulsification combined with endoscopic cyclophotocoagulation (phaco-ECP) with the eyes that underwent phacoemulsification alone. METHODS: A retrospective case series review of 103 consecutive eyes that underwent phaco-ECP and 62 eyes that underwent phacoemulsification between January 2006 and August 2012 was conducted. Post-operative refractive outcomes were obtained by subjective refraction or autorefraction. Demographic data, best corrected visual acuity, intraocular pressure, number of glaucoma agents and mean deviation of the Humphrey visual field test (MD) were also analysed. RESULTS: The total number of eyes included in the study was 62 eyes for the phaco-ECP group and 62 eyes for the control group who underwent phacoemulsification alone. More than 90% of eyes (n = 56) in phaco-ECP group achieved post-operative refraction within ±1 dioptre (D) of the target refraction. In the control group, 100% of eyes achieved post-operative refraction within ±1D of the target refraction. When comparing the difference between the target and the actual refractive outcome between the phaco-ECP and the control group, there was no statistically significant difference. CONCLUSIONS: Refractive outcome after phaco-ECP is comparable to phacoemulsification alone. This study suggests that the intraocular lens power can be selected for cataract surgery alone and that ECP does not change the effective lens position significantly; therefore, no modification of biometry formulae is required. Phaco-ECP should be considered as an effective, safe and predictable surgical treatment option for glaucoma patients with co-existing cataract.


Assuntos
Glaucoma/cirurgia , Fotocoagulação a Laser/métodos , Facoemulsificação , Erros de Refração/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Feminino , Glaucoma/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Refração Ocular/fisiologia , Estudos Retrospectivos
4.
Phys Rev Lett ; 115(12): 121604, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26430984

RESUMO

We report a measurement of the time-dependent CP asymmetry of B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays, where the light neutral hadron h^{0} is a π^{0}, η, or ω meson, and the neutral D meson is reconstructed in the CP eigenstates K^{+}K^{-}, K_{S}^{0}π^{0}, or K_{S}^{0}ω. The measurement is performed combining the final data samples collected at the ϒ(4S) resonance by the BABAR and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6} BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6} BB[over ¯] pairs recorded by the Belle detector. We measure the CP asymmetry parameters -η_{f}S=+0.66±0.10(stat)±0.06(syst) and C=-0.02±0.07(stat)±0.03(syst). These results correspond to the first observation of CP violation in B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations.

5.
Oecologia ; 173(4): 1249-59, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23843036

RESUMO

In theory, habitat preferences should be adaptive. Accordingly, fitness is often assumed to be greater in preferred habitats; however, this assumption is rarely tested and, when it is, the results are often equivocal. Habitat preferences may not directly convey fitness advantages if animals are constrained by tradeoffs with other selective pressures like predation or food availability. We address unresolved questions about the survival consequences of habitat choices made during brood-rearing in a precocial species with exclusive maternal care (mallard Anas platyrhynchos, n = 582 radio-marked females on 27 sites over 8 years). We directly linked duckling survival with habitat selection patterns at two spatial scales using logistic regression and model selection techniques. At the landscape scale (55-80 km(2)), females that demonstrated stronger selection of areas with more cover type 4 wetlands and greater total cover type 3 wetland area (wetlands with large expanses of open water surrounded by either a narrow or wide peripheral band of vegetation, respectively) had lower duckling survival rates than did females that demonstrated weaker selection of these habitats. At finer scales (0.32-7.16 km(2)), females selected brood-rearing areas with a greater proportion of wetland habitat with no consequences for duckling survival. However, females that avoided woody perennial habitats composed of trees and shrubs fledged more ducklings. The relationship between habitat selection and survival depended on both spatial scale and habitats considered. Females did not consistently select brood-rearing habitats that conferred the greatest benefits, an unexpected finding, although one that has also been reported in other recent studies of breeding birds.


Assuntos
Comportamento de Escolha , Patos , Ecossistema , Animais , Comportamento Animal , Canadá , Feminino , Modelos Logísticos , Comportamento Predatório , Áreas Alagadas
6.
Clin Transl Gastroenterol ; 13(10): e00522, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-36000993

RESUMO

INTRODUCTION: Several complications of decompensated cirrhosis are believed to result from increased intestinal permeability. However, little is known about the relationship between mucosal bacteria and epithelial permeability in cirrhosis. We aimed to assess epithelial permeability and associations with mucosal bacteria in patients with compensated cirrhosis. METHODS: We obtained duodenal tissue biopsies from patients with compensated cirrhosis and controls. Patients were excluded if they used antibiotics or immunosuppression. The composition of mucosal microbiota was determined by 16S rRNA gene sequencing and epithelial permeability by transepithelial electrical resistance (TEER) and tight junction protein expression. RESULTS: We studied 24 patients with compensated cirrhosis and 20 controls. Patients with cirrhosis were older than controls (62 vs 52 years, P = 0.02) but had a similar number of extrahepatic comorbidities (2.2 vs 1.4, P = 0.13). Patients with compensated cirrhosis had lower duodenal TEER (i.e., increased epithelial permeability; 13.3 Ω/cm 2 ± 3.4 vs 18.9 Ω/cm 2 ± 7.1; P = 0.004). Patients with compensated cirrhosis trended toward a distinct mucosal microbiota community structure relative to controls ( P = 0.09). Clustering analysis identified two unique enterotypes. These enterotypes differed in bacterial composition and also TEER. A beta-binomial model found 13 individual bacteria associated with TEER, including Lactobacillus and Bifidobacterium taxa. Thirty-six taxa were associated with tight junction protein expression, including Lactobacillus and Bifidobacterium. DISCUSSION: Compensated cirrhosis is characterized by increased duodenal epithelial permeability with a distinct mucosal microbial community. Intriguingly, bacteria previously associated with health were protective of duodenal permeability.


Assuntos
Mucosa Intestinal , Microbiota , Humanos , RNA Ribossômico 16S/genética , Mucosa Intestinal/patologia , Permeabilidade , Cirrose Hepática/patologia , Proteínas de Junções Íntimas/metabolismo , Bactérias/genética
7.
J Environ Qual ; 48(2): 217-232, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30951132

RESUMO

To study the structure and function of soil organic matter, soil scientists have performed alkali extractions for soil humic acid (HA) and fulvic acid (FA) fractions for more than 200 years. Over the last few decades aquatic scientists have used similar fractions of dissolved organic matter, extracted by resin adsorption followed by alkali desorption. Critics have claimed that alkali-extractable fractions are laboratory artifacts, hence unsuitable for studying natural organic matter structure and function in field conditions. In response, this review first addresses specific conceptual concerns about humic fractions. Then we discuss several case studies in which HA and FA were extracted from soils, waters, and organic materials to address meaningful problems across diverse research settings. Specifically, one case study demonstrated the importance of humic substances for understanding transport and bioavailability of persistent organic pollutants. An understanding of metal binding sites in FA and HA proved essential to accurately model metal ion behavior in soil and water. In landscape-based studies, pesticides were preferentially bound to HA, reducing their mobility. Compost maturity and acceptability of other organic waste for land application were well evaluated by properties of HA extracted from these materials. A young humic fraction helped understand N cycling in paddy rice ( L.) soils, leading to improved rice management. The HA and FA fractions accurately represent natural organic matter across multiple environments, source materials, and research objectives. Studying them can help resolve important scientific and practical issues.


Assuntos
Monitoramento Ambiental , Substâncias Húmicas/análise , Agricultura , Álcalis , Benzopiranos/análise , Água Doce/química , Solo/química
8.
Ophthalmology ; 115(6): 993-1001.e2, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18031818

RESUMO

OBJECTIVE: To compare the binocular near vision performance in patients implanted with the 1CU accommodating intraocular lens (IOL) with a multifocal and monofocal IOL. DESIGN: Prospective, randomized, double-masked clinical trial. PARTICIPANTS: Ninety patients presenting for cataract surgery to the Department of Ophthalmology, Hillingdon Hospital were randomized to receive the 1CU accommodative IOL, a multifocal IOL, or a monofocal IOL (control group). METHODS: Patients underwent bilateral sequential phacoemulsification with implantation of 1 of the 3 IOL types and were assessed at 3 and 18 months after second-eye surgery. MAIN OUTCOME MEASURES: Logarithm of the minimum angle of resolution distance and near visual acuities (VAs) (unaided and distance corrected), contrast sensitivity, and accommodative amplitude (near point and defocusing) were measured at 3 and 18 months. Reading speed was assessed at 18 months, and glare symptoms and spectacle independence were compared using a standardized questionnaire. RESULTS: Mean unaided and distance-corrected binocular near VAs were similar in the 1CU and multifocal and were significantly higher than the control group's (P<0.02). There was no significant difference in reading speed between any of the groups, but critical print sizes were similar in the 1CU and multifocal groups and significantly better than the control group's (P = 0.02). The accommodative range was highest in the multifocal group and lowest in the control group, and there was no significant difference between the 1CU and control groups for defocus or near point at 18 months. Of the 1CU group and control group, 71.4% and 63.2%, respectively, experienced no glare at 18 months, compared with only 25% of the multifocal group (P = 0.01). Of the 1CU group and multifocal group, 19% and 27.3%, respectively, were completely spectacle independent at 18 months; none of the control group was (P = 0.05). CONCLUSIONS: The 1CU accommodating IOL provides improved near vision compared with a monofocal IOL. There is a discrepancy between the near function and accommodative amplitude measured in the 1CU. The multifocal provides excellent near acuity, but photopic phenomena remain a problem inherent in the lens design.


Assuntos
Acomodação Ocular/fisiologia , Implante de Lente Intraocular , Lentes Intraoculares , Facoemulsificação , Visão Binocular/fisiologia , Acuidade Visual/fisiologia , Idoso , Sensibilidades de Contraste/fisiologia , Método Duplo-Cego , Feminino , Ofuscação , Humanos , Masculino , Estudos Prospectivos , Leitura , Inquéritos e Questionários
9.
Curr Biol ; 10(14): R516-7, 2000 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-10898995

RESUMO

Many philosophers and psychologists believe that only people with rich language skills are capable of abstract reasoning. A man with a severe linguistic impairment poses a striking challenge to this view.


Assuntos
Lesões Encefálicas/psicologia , Transtornos da Linguagem/psicologia , Pensamento/fisiologia , Humanos , Idioma , Linguística , Masculino , Modelos Psicológicos
10.
Curr Biol ; 9(4): R127-8, 1999 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-10074422

RESUMO

Recent studies of children with developmental disorders provide striking insights into the nature of language. These studies suggest that, although much of language arises from more general cognitive capacities, certain aspects of grammar have an autonomous psychological and neural basis.


Assuntos
Deficiências do Desenvolvimento/psicologia , Idioma , Linguística , Criança , Humanos
11.
Trends Cogn Sci ; 1(1): 9-12, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21223847

RESUMO

Humans intuitively think about the actions of others in terms of mental states eliefs, desires, emotions and intentions. This 'theory of mind' plays a central role in how children learn the meanings of certain words. First, it underlies how they determine the reference of a novel word. When children hear a new object name (e.g. 'Look at the fendle'), they do not use spatio-temporal contiguity to determine what the word describes; instead they focus on cues to the referential intention of the speaker, such as direction of gaze. Second, an understanding of purpose and design is sometimes necessary to enable the child to understand the entities and actions that nouns and verbs refer to. This is particularly relevant for nouns that refer to collections of objects such as 'family' and 'game', and for verbs that refer to actions defined in terms of an actor's goals, such as 'give' and 'make'. Finally, intentional considerations partially underlie the generalization of names for artifact categories, such as 'chair' and 'clock', which can refer to entities of highly dissimilar appearance.

12.
Trends Cogn Sci ; 2(2): 67-73, 1998 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-21227068

RESUMO

Children are strikingly good at learning the meanings of words. Current controversy focuses on the relative importance of different capacities in this learning process including principles of association, low-level attentional mechanisms, special word learning constraints, syntactic cues and theory of mind. We argue that children succeed at word learning because they possess certain conceptual biases about the external world, the ability to infer the referential intentions of others and an appreciation of syntactic cues to word meaning. Support for this view comes from studies exploring the phenomena of fast mapping, the whole object bias, the acquisition of names for entities belonging to different ontological kinds and the effect of lexical contrast. Word learning is not the result of a general associative learning process, nor does it involve specialized constraints. The ability to learn the meanings of words depends on a number of capacities, some of which are specific to language and unique to humans, others of which are potentially shared with other species.

13.
Eye (Lond) ; 29(10): 1260-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26293138

RESUMO

Glaucoma is one of the leading causes of blindness worldwide and will affect 79.6 million people worldwide by 2020. It is caused by the progressive loss of retinal ganglion cells (RGCs), predominantly via apoptosis, within the retinal nerve fibre layer and the corresponding loss of axons of the optic nerve head. One of its most devastating features is its late diagnosis and the resulting irreversible visual loss that is often predictable. Current diagnostic tools require significant RGC or functional visual field loss before the threshold for detection of glaucoma may be reached. To propel the efficacy of therapeutics in glaucoma, an earlier diagnostic tool is required. Recent advances in retinal imaging, including optical coherence tomography, confocal scanning laser ophthalmoscopy, and adaptive optics, have propelled both glaucoma research and clinical diagnostics and therapeutics. However, an ideal imaging technique to diagnose and monitor glaucoma would image RGCs non-invasively with high specificity and sensitivity in vivo. It may confirm the presence of healthy RGCs, such as in transgenic models or retrograde labelling, or detect subtle changes in the number of unhealthy or apoptotic RGCs, such as detection of apoptosing retinal cells (DARC). Although many of these advances have not yet been introduced to the clinical arena, their successes in animal studies are enthralling. This review will illustrate the challenges of imaging RGCs, the main retinal imaging modalities, the in vivo techniques to augment these as specific RGC-imaging tools and their potential for translation to the glaucoma clinic.


Assuntos
Axônios/patologia , Diagnóstico por Imagem/métodos , Técnicas de Diagnóstico Oftalmológico , Glaucoma/diagnóstico , Disco Óptico/patologia , Doenças do Nervo Óptico/diagnóstico , Células Ganglionares da Retina/patologia , Apoptose , Humanos
14.
Neuropsychologia ; 22(5): 559-68, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6504296

RESUMO

Subjects decided whether self-referential statements were true or false. Event-related potentials (ERPs) associated with final words creating false statements displayed a late negativity (N340) relative to ERPs for true completions. The size of this difference between true and false statements was greater for highly familiar statements (e.g. "My name is Ira") than for less familiar ones (e.g. "I go to bed late") even after all the statements had been practised a number of times. The late negativity appears to be associated with a discrepancy between presented and remembered information, and its magnitude reflects the long-term familiarity or strength of the remembered information.


Assuntos
Córtex Cerebral/fisiologia , Memória/fisiologia , Rememoração Mental/fisiologia , Semântica , Percepção da Fala/fisiologia , Adulto , Potenciais Evocados Auditivos , Humanos , Tempo de Reação/fisiologia
15.
Am J Med ; 69(2): 325-8, 1980 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7405950

RESUMO

A patient with autoimmune renal failure, cavitary lung lesions and arthritis experienced pancytopenia while prednisone therapy was being tapered. Utilizing semisolid culture techniques, a population of nonadherent peripheral blood mononuclear cells was demonstrated, which inhibited autologous but not allogeneic bone marrow erythroid colony-forming units (CFU-E) and myeloid colony-forming units (CFU-c) in vitro. No inhibition of CFU-E or CFU-c colony formation was seen when patient's serum or immunoglobulin G (IgG) was added to cultures. Reinstitution of prednisone therapy resulted in normalization of peripheral blood counts, which was accompanied by the loss of the hemopoietic inhibitor cell activity in the patient's peripheral blood. These results demonstrate the need for testing autologous marrow samples when looking for possible immune-mediated inhibition of hematopoiesis.


Assuntos
Doenças Autoimunes/imunologia , Células-Tronco Hematopoéticas/imunologia , Linfócitos/imunologia , Pancitopenia/imunologia , Adulto , Doenças Autoimunes/tratamento farmacológico , Osso e Ossos , Hematopoese , Humanos , Imunoglobulina G/imunologia , Masculino , Prednisona/uso terapêutico
16.
Am J Med ; 64(6): 1056-60, 1978 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-350044

RESUMO

A glomerular lesion identical to that of IgA nephropathy was demonstrated unexpectedly in a 17 year old boy who presented with clinical manifestations of pulmonary hemosiderosis and with no evidence of renal disease. This subclinical glomerular lesion would have remained undetected in this patient unless kidney tissue was obtained and examined by immunofluorescence or electron microscopy. It is unknown if the glomerular lesion in this case is causally related to pulmonary hemosiderosis.


Assuntos
Glomerulonefrite/patologia , Hemossiderose/patologia , Imunoglobulina A/análise , Pneumonia/patologia , Insuficiência Respiratória/patologia , Adolescente , Complemento C3/análise , Imunofluorescência , Glomerulonefrite/imunologia , Hemossiderose/imunologia , Humanos , Glomérulos Renais/imunologia , Glomérulos Renais/patologia , Pulmão/patologia , Masculino , Pneumonia/imunologia
17.
Transplantation ; 47(2): 290-2, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2645715

RESUMO

The clinical and histological spectrum of renal allograft rejection occurring in the early posttransplant period is well described, but there is not much information with regard to the nature of graft rejection occurring in the long-term survivors of renal transplantation. In this study, we analyzed the incidence, clinical and histological data, and outcome of graft rejection in 69 patients who survived with a functioning kidney for 10 years or longer. In this second decade, during a mean follow-up of 3 years (0.1-9.7 years), 15 patients (22%) developed 20 late rejections. Two of them received living-donor transplants and 13 received cadaver kidneys. Only 8 of these rejections (40%) were associated with abnormal clinical findings; the other 12 (60%) were asymptomatic and were detected on the basis of an unexplained deterioration in graft function. The diagnosis was made on clinical grounds in 10 cases and the other 10 were confirmed by renal histology: acute cellular rejection 1, acute cellular rejection superimposed on chronic rejection 4, and chronic rejection only 5. Thirteen acute rejections in 8 patients were treated with high-dose steroids. Of these, 6 (46%) responded fully, 4 (31%) responded partially, and 3 (23%) did not respond. Seven patients with chronic rejection were not treated. Of these, 5 have returned to dialysis within a mean period of 8 months and one patient died of hepatic failure. Our data suggest that acute reversible graft rejections can occur even after 10 years following renal transplantation. It is therefore essential to continue the maintenance immunosuppressive therapy and monitor the clinical and renal functional data at regular intervals in long-term survivors of renal transplantation.


Assuntos
Rejeição de Enxerto , Transplante de Rim , Longevidade , Adolescente , Adulto , Creatinina/sangue , Feminino , Seguimentos , Rejeição de Enxerto/efeitos dos fármacos , Humanos , Rim/patologia , Rim/fisiopatologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/tratamento farmacológico , Recidiva
18.
Cognition ; 60(1): 1-29, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8766388

RESUMO

What determines our intuitions as to which objects are members of specific artifact kinds? Prior research suggests that factors such as physical appearance, current use, and intended function are not at the core of concepts such as chair, clock and pawn. The theory presented here, based on Levinson's (1993) intentional-historical theory of our concept of art, is that we determine that something is a member of a given artifact kind by inferring that it was successfully created with the intention to belong to that kind. This theory can explain why some properties (such as shape) are more important than others (such as color) when we determine kind membership and can account for why certain objects are judged to be members of artifact kinds even though they are highly dissimilar from other members of the kinds. It can also provide a framework for explaining the conditions under which broken objects cease to be members of their kinds and new artifacts can come into existence. This account of our understanding of artifact concepts is argued to be consistent with more general "essentialist" theories of our understanding of concepts corresponding to proper names and natural kind terms.


Assuntos
Artefatos , Cognição , Arte , Humanos , Percepção Visual
19.
Cognition ; 56(1): 1-30, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7634763

RESUMO

One basic finding in the study of word learning is that children tend to construe a word describing an object as referring to the kind of whole object, rather than to a part of the object, one of its properties, or the substance it is made of. This has been taken as evidence that there exist certain special constraints on word meaning that guide children to favor the kind-of-object interpretation when exposed to a new word. There are descriptive problems with this proposal, however, as it cannot explain how children learn other kinds of words, such as names for specific people, substances, parts, events, collections, and periods of time. These problems motivate an alternative theory in which young children possess several distinct conceptual categories--including "individual", which is more abstract than "whole object"--and can use syntactic cues to determine the conceptual category that a new word belongs to. This theory is explored in two experiments in which we attempt to use syntactic cues to teach children and adults novel collective nouns--words that refer to groups of objects. The results indicate that children can use such cues to learn names for kinds of individuals that are not whole objects, although they are less able to do so than adults. Candidate explanations for why this developmental difference exists are discussed and implications are drawn for theories of word learning and conceptual representation.


Assuntos
Formação de Conceito , Desenvolvimento da Linguagem , Semântica , Aprendizagem Verbal , Adulto , Pré-Escolar , Feminino , Generalização do Estímulo , Humanos , Masculino , Rememoração Mental , Reconhecimento Visual de Modelos , Psicolinguística , Vocabulário
20.
Cognition ; 71(1): B1-9, 1999 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-10394710

RESUMO

Heider and Simmel [Heider, F., Simmel, M., 1944. An experimental study of apparent behavior. American Journal of Psychology 57, 243-259] found that people spontaneously describe depictions of simple moving objects in terms of purposeful and intentional action. Not all intentional beings are objects, however, and people often attribute purposeful activity to non-object individuals such as countries, basketball teams, and families. This raises the question of whether the same effect found by Heider and Simmel would hold for non-object individuals such as groups. We replicate and extend the original study, using both objects and groups as stimuli, and introducing two control conditions with groups that are not engaged in structured movement. We found that under the condition that best promoted the attribution of intentionality, moving groups are viewed as purposeful and goal-directed entities to the same extent that moving objects are. These results suggest that the psychological distinction between the notion of 'intentional entity' and the notion of 'object' can be found even in the perception of moving geometrical figures.


Assuntos
Processos Grupais , Ilusões/psicologia , Percepção de Movimento/fisiologia , Motivação , Percepção Social , Adulto , Análise de Variância , Humanos
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