933 resultados para theories of action
Resumo:
The interaction between natural and sexual selection is central to many theories of how mate choice and reproductive isolation evolve, but their joint effect on the evolution of mate recognition has not, to my knowledge, been investigated in an evolutionary experiment. Natural and sexual selection were manipulated in interspecific hybrid populations of Drosophila to determine their effects on the evolution of a mate recognition system comprised of cuticular hydrocarbons (CHCs). The effect of natural selection in isolation indicated that CHCs were costly for males and females to produce. The effect of sexual selection in isolation indicated that females preferred males with a particular CHC composition. However, the interaction between natural and sexual selection had a greater effect on the evolution of the mate recognition system than either process in isolation. When natural and sexual selection were permitted to operate in combination, male CHCs became exaggerated to a greater extent than in the presence of sexual selection alone, and female CHCs evolved against the direction of natural selection. This experiment demonstrated that the interaction between natural and sexual selection is critical in determining the direction and magnitude of the evolutionary response of the mate recognition system.
Resumo:
Animal-based theories of Pavlovian conditioning propose that patterning discriminations are solved using unique cues or immediate configuring. Recent studies with humans, however, provided evidence that in positive and negative patterning two different rules are utilized. The present experiment was designed to provide further support for this proposal by tracking the time course of the allocation of cognitive resources. One group was trained in a positive patterning; schedule (A-, B-, AB+) and a second in a negative patterning schedule (A+, B+, AB-). Electrodermal responses and secondary task probe reaction time were measured. In negative patterning, reaction times were slower during reinforced stimuli than during non-reinforced stimuli at both probe positions while there were no differences in positive patterning. These results support the assumption that negative patterning is solved using a rule that is more complex and requires more resources than does the rule employed to solve positive patterning. (C) 2001 Elsevier Science (USA).
Resumo:
Backhousia citriodora is typical of the many commercially valuable woody Australian Myrtaceae species that are recalcitrant in forming adventitious roots from cuttings after maturation. A series of experiments were conducted to identify an endogenous rooting inhibitor in line with established criteria. Endogenous levels of citral were correlated with the rooting capacities of juvenile versus mature, and easy- versus difficult-to-root genotypes of B. citriodora, in both winter and summer. The biological activity of citral was confirmed in bioassays on mung beans and easy-to-root B. citriodora seedlings. Evidence of a common mechanism of root inhibition with other species in the Myrtaceae and the role of action of citral are discussed.
Resumo:
Background: Thalamotomy has been reported to be successful in ameliorating the motor symptoms of tremor and/or rigidity in people with Parkinson's disease (PD), emphasising the bona fide contribution of this subcortical nucleus to the neural circuitry subserving motor function. Despite evidence of parallel yet segregated associative and motor cortico-subcortical-cortical circuits, comparatively few studies have investigated the effects of this procedure on cognitive functions. In particular, research pertaining to the impact of thalamotomy on linguistic processes is fundamentally lacking. Aims: The purpose of this research was to investigate the effects of thalamotomy in the language dominant and non-dominant hemispheres on linguistic functioning, relative to operative theoretical models of subcortical participation in language. This paper compares the linguistic profiles of two males with PD, aged 75 years (10 years of formal education) and 62 years (22 years of formal education), subsequent to unilateral thalamotomy procedures within the language dominant and non-dominant hemispheres, respectively. Methods & Procedures: Comprehensive linguistic profiles comprising general and high-level linguistic abilities in addition to on-line semantic processing skills were compiled up to 1 month prior to surgery and 3 months post-operatively, within perceived on'' periods (i.e., when optimally medicated). Pre- and post-operative language performances were compared within-subjects to a group of 16 non-surgical Parkinson's controls (NSPD) and a group of 16 non-neurologically impaired adults (NC). Outcomes & Results: The findings of this research suggest a laterality effect with regard to the contribution of the thalamus to high-level linguistic abilities and, potentially, the temporal processing of semantic information. This outcome supports the application of high-level linguistic assessments and measures of semantic processing proficiency to the clinical management of individuals with dominant thalamic lesions. Conclusions: The results reported lend support to contemporary theories of dominant thalamic participation in language, serving to further elucidate our current understanding of the role of subcortical structures in mediating linguistic processes, relevant to cortical hemispheric dominance.
Resumo:
Cylindrospermopsin (CYN) is a hepatotoxin isolated from the blue-green alga Cylindrospermopsis raciborskii. The role of both glutathione (GSH) and the cytochrome P450 enzyme system (P450) in the mechanism of toxicity of CYN has been previously investigated in in vitro systems. We have investigated the role of GSH and P450 in vivo in mice. Mice pre-treated with buthionine sulphoximine and diethyl maleate to deplete hepatic GSH prior to dosing with 0.2 mg/kg CYN showed a seven-day survival rate of 5/13 while the control group rate was 9/14. Dosing mice with 0.2 mg/kg CYN produced a small decrease in hepatic GSH with a characteristic rebound effect at 24 h, The magnitude of this effect is however small and combined with the non-significant difference in survival rates after GSH depletion suggest depletion of GSH by CYN could not be a primary mechanism for CYN toxicity, Conversely, pro-treatment with piperonyl butoxide, a P450 inhibitor, protected mice against CYN toxicity giving a survival rate of 10/10 compared with 4/10 in the control group (p < 0.05 Chi squared) and was protective at doses up to 0.8 mg/kg, suggesting activation of CYN by P450 is of primary importance in the mechanism of action. (C) 2002 Elsevier Science Ltd. All rights reserved.
Resumo:
Venous thromboembolism is a frequent, life-threatening, postoperative complication of hip-fracture and total-knee-replacement surgery. Fondaparinux is a synthetic polysaccharide that selectively binds to antithrombin, the primary endogenous regulator of blood coagulation. Low molecular weight heparins, such as enoxaparin, are less specific inhibitors of coagulation. In patients undergoing hip-fracture surgery, fondaparinux is more effective than once-daily enoxaparin as prophylaxis for venous thromboembolism. Fondaparinux (25 mg/day s.c.) was also more effective than enoxaparin (30 mg s.c. b.i.d.) as prophylaxis for venous thromboembolism in elective knee surgery. These differences may be explained by the fact that there is less prophylaxis cover with enoxaparin, as it has a much shorter duration of action than fondaparinux. Thus, with the present dosing regimens, fondaparinux is probably preferable to enoxaparin for the prevention of venous thromboembolism.
Resumo:
Early pregnancy factor (EPF) is a secreted protein with growth regulatory and immunomodulatory properties. It is an extracellular form of the mitochondrial matrix protein chaperonin 10 (Cpn10), a molecular chaperone. An understanding of the mechanism of action of EPF and an exploration of therapeutic potential has been limited by availability of purified material. The present study was undertaken to develop a simple high-yielding procedure for preparation of material for structure/function studies, which could be scaled up for therapeutic application. Human EPF was expressed in Sf9 insect cells by baculovirus infection and in Escherichia coli using a heat inducible vector. A modified molecule with an additional N-terminal alanine was also expressed in E coli. The soluble protein was purified from cell lysates via anion exchange (negative-binding mode), cation exchange, and hydrophobic interaction chromatography, yielding similar to42 and 36 mg EPF from 300 ml bacterial and I L Sf9 cultures, respectively. The preparations were highly purified ( greater than or equal to99% purity on SDS-PAGE for the bacterial products and greater than or equal to97% for that of insect cells) and had the expected mass and heptameric structure under native conditions, as determined by mass spectrometry and gel permeation chromatography, respectively. All recombinant preparations exhibited activity in the EPF bioassay, the rosette inhibition test, with similar potency both to each other and to the native molecule. In two in vivo assays of immuno suppressive activity, the delayed-type hypersensitivity reaction and experimental autoimmune encephalomyelitis, the insect cell and modified bacterial products, both with N-terminal additions (acetylation or amino acid), exhibited similar levels of suppressive activity, but the bacterial product with no N-terminal modification had no effect in either assay. Studies by others have shown that N-terminal addition is not necessary for Cpn10 activity. By defining techniques for facile production of molecules with and without immunosuppressive properties, the present studies make it possible to explore mechanisms underlying the distinction between EPF and Cpn10 activity. (C) 2003 Elsevier Inc. All rights reserved.
Writing the body of the mother: Narrative moments in Tsushima Yuko, Ariyoshi Sawako and Enchi Fumiko
Resumo:
This discussion argues the transformative potential inherent in the corporeal experience of motherhood as represented in selected textual moments of Japanese narrative. Narratives that address the experiences of the body of the mother are informed and given substance by an intense physicality, and thus have the potential to contest processes of social inscription in addition to suggesting alternative possibilities for all readers, not just those occupying an embodied maternal space. The discussion features brief events from the work of three writers who have written as mothers: Tsushima Y(u)macrko, Ariyoshi Sawako and Enchi Fumiko. In Yama o hashiru onna (1980; translated as Woman Running in the Mountains, 1991), Tsushima Y(u)macrko invites the reader to consider the embodied response to light of Takiko, a young pregnant woman. Emiko, the protagonist of Hishoku (Without Colour, 1967) by Ariyoshi Sawako, is the Japanese wife of an African American and has just given birth to a child. The daughter protagonist in Enchi Fumiko's 'Kami' ('Hair', 1957) operates a hairdressing business that is viable only with her mother's unpaid labour. The narratives are read through a matrix of post-structuralist theories of embodiment, drawing on the work of writers such as Julia Kristeva, Luce Irigaray and Elizabeth Grosz.
Resumo:
delta-Atracotoxin-Ar1a (delta-ACTX-Ar1a) is the major polypeptide neurotoxin isolated from the venom of the male Sydney funnel-web spider, Atrax robustus. This neurotoxin targets both insect and mammalian voltage-gated sodium channels, where it competes with scorpion alpha-toxins for neurotoxin receptor site-3 to slow sodium-channel inactivation. Progress in characterizing the structure and mechanism of action of this toxin has been hampered by the limited supply of pure toxin from natural sources. In this paper, we describe the first successful chemical synthesis and oxidative refolding of the four-disulfide bond containing delta-ACTX-Ar1a. This synthesis involved solid-phase Boc chemistry using double coupling, followed by oxidative folding of purified peptide using a buffer of 2 M GdnHCl and glutathione/glutathiol in a 1:1 mixture of 2-propanol (pH 8.5). Successful oxidation and refolding was confirmed using both chemical and pharmacological characterization. Ion spray mass spectrometry was employed to confirm the molecular weight. H-1 NMR analysis showed identical chemical shifts for native and synthetic toxins, indicating that the synthetic toxin adopts the native fold. Pharmacological studies employing whole-cell patch clamp recordings from rat dorsal root ganglion neurons confirmed that synthetic delta-ACTX-Ar1a produced a slowing of the sodium current inactivation and hyperpolarizing shifts in the voltage-dependence of activation and inactivation similar to native toxin. Under current clamp conditions, we show for the first time that delta-ACTX-Ar1a produces spontaneous repetitive plateau potentials underlying the clinical symptoms seen during envenomation. This successful oxidative refolding of synthetic delta-ACTX-Ar1a paves the way for future structure-activity studies to determine the toxin pharmacophore.
Resumo:
The idea of “human security” is gaining attention among policy-makers and security analysts. Little scholarly attention has been given to the questions of why states accept (or reject) a human security agenda or how such an agenda is incorporated into policy practices. The article suggests that a human security approach is most likely to be applied when both humanitarian and national interests combine. Yet when states or organisations adopt a human security approach, they often misjudge the complex and long-term commitment required of such an approach. There is also the potential for such an agenda to be manipulated to justify questionable courses of action. These issues frame an analysis of six recent case studies.
Resumo:
Visando a proteção da propriedade industrial advinda de uma região demarcada, surgiu a Indicação Geográfica (IG). O registro da IG é conferido aos produtos ou serviços característicos de seu local de origem, apresentando qualidades únicas em função dos recursos naturais. Além disso, a IG é responsável por distinguir estes produtos em relação aos disponíveis no mercado. Neste contexto, entidades como Sebrae, MAPA e INPI, têm promovido ações estratégicas com o objetivo de apoiar a proteção do saber fazer e consequentemente, os produtos tradicionais das regiões. Tais entidades são responsáveis por promover a sustentabilidade do processo juntos aos produtores, assim como disseminar o selo para os consumidores. Assim, iniciativas como esta precisam ser apoiadas a fim de entregar resultados significativos para o desenvolvimento das regiões e seus respectivos produtos com o selo de IG. O Plano de Apoio à Gestão da Indicação Geográfica desenvolvido pelo Sebrae/ES tem três pilares: melhoria do processo de produção, promoção do produto e a sustentabilidade do processo. A presente pesquisa, baseando-se nas teorias sobre estratégia e implementação de estratégias, analisa os fatores intervenientes que contribuem para o sucesso da implementação do Plano de Apoio à Gestão da indicação geográfica das Panelas de Barro de Goiabeiras, bairro do município de Vitória, capital do Espírito Santo. A pesquisa é um estudo de caso de natureza qualitativa, exploratória e descritiva ex-post-facto. Os dados foram coletados nos documentos (plano de ação do Sebrae/ES, Livro dos Saberes e relatórios desenvolvidos por consultores especializados) e por meio de entrevistas com seis agentes de políticas públicas e cinco paneleiras, envolvidos na elaboração e implementação do plano de ação. Para a análise dos dados, adotou-se a metodologia de análise de conteúdo com index definido a posteriori. Do Plano de Apoio à Gestão da IG das Paneleiras de Goiabeiras, foram agrupadas três ações estratégicas buscando identificar em que medida os fatores intervenientes afetaram a implementação de cada ação estudada: Ação1: fortalecimento dos aspectos culturais do produto, Ação 2: fortalecimento dos aspectos sociais do produto e Ação 3: fortalecimento dos aspectos econômicos associados à diferenciação por IG. Os resultados mostraram que na Ação 1 o fator interveniente liderança superou as expectativas na implementação das estratégias. Já os aspectos políticos, o acompanhamento de resultados e a estrutura organizacional desenvolveram as ações conforme o planejado, enquanto os fatores intervenientes cultura e clareza nas estratégias apresentaram oportunidades de melhorias. Na Ação 2 somente os fatores intervenientes recursos, cultura e clareza nas estratégias apresentaram-se de acordo com o proposto, enquanto a liderança e a estrutura organizacional mostraram-se como pontos de oportunidades de melhoria. Por fim, na Ação 3 nenhum fator interveniente foi destaque como uma oportunidade de melhoria. A estrutura organizacional e os aspectos políticos apresentaram-se de acordo, enquanto os recursos e a liderança superaram as expectativas.
Resumo:
This work presents a reflection on Design education and specifically on the role of Drawing in this area. As a subject, Design has expanded its field of action expanding into new areas such as Experience Design or Service Design. It became necessary for the designer to have more than an education based on technological knowledge or know-how. Many authors like Meredith Davis, Don Norman or Jamie Hobson point out the urgency to review the curricula of Design courses because nowadays “… design is more than appearance, design is about interaction, about strategy and about services. Designers change social behavior” (Norman 2011). When shifting from a product-centered design to a person-centered design (in a structure, a service or in a relationship) what should the function of drawing in a design course be? What should its curriculum be? Our work methodology will be to confront today’s perspectives on design theory and practice in an attempt to add to the discussion on the methodological strategies in design teaching in the contemporary context.
Resumo:
This work presents a reflection on Design education and specifically on the role of Drawing in this area. As a subject, Design has expanded its field of action expanding into new areas such as Experience Design or Service Design. It became necessary for the designer to have more than an education based on technological knowledge or know-how. Many authors like Meredith Davis, Don Norman or Jamie Hobson point out the urgency to review the curricula of Design courses because nowadays “ … design is more than appearance, design is about interaction, about strategy and about services. Designers change social behavior” (Norman, 2011) When shifting from a product-centered design to a person-centered design (in a structure, a service or in a relationship) what should the function of drawing in a design course be? What should its curriculum be? Our work methodology will be to confront today’s perspectives on design theory and practice in an attempt to add to the discussion on the methodological strategies in design teaching in the contemporary context.
Resumo:
This article reports evidence of new monetary channels for social inclusion involving basic income policies and the Caixa Econômica Federal, a Brazilian government savings bank. Since the Plano Real (Brazilian currency) and the liberalization of banking in the 1990s, the realization of competitive advantages by the Caixa as social policy agent and the importance of citizenship cards differ from existing theories of bank change, financial inclusion and monetary policy. Multi-method research reveals the importance of 1) political theories of basic income, 2) conceptions of citizenship and social justice, and 3) a back to the future modernization of government banking. This provides alternatives to contemporary market-based banking theory, neo-liberal policies, private and non-governmental microfinance strategies, and theories in political economy about fiscal constraints to social policies. New monetary channels of change also suggest that zero sum theories about politics, monetary authority and social inclusion are amiss.
Resumo:
How the policy of action and professional standards have influenced the development and decentralization of health education is discussed. It is concluded that a review of policies both of developing as well as of developed countries could help to put some observations into a perspective that is closer to the Brazilian reality.