Piezoelectricity and ferroelectricity in amino acid glycine

Bioorganic ferroelectrics and piezoelectrics are becoming increasingly important in view of their intrinsic compatibility with biological environment and biofunctionality combined with strong piezoelectric effect and switchable polarization at room temperature. Here we study piezoelectricity and ferroelectricity in the smallest amino acid glycine, representing a broad class of non-centrosymmetric amino acids. Glycine is one of the basic and important elements in biology, as it serves as a building block for proteins. Three polymorphic forms with different physical properties are possible in glycine (α, β and γ), Of special interest for various applications are non-centrosymmetric polymorphs: β-glycine and γ-glycine. The most useful β-polymorph being ferroelectric took much less attention than the other due to its instability under ambient conditions. In this work, we could grow stable microcrystals of β-glycine by the evaporation of aqueous solution on a (111)Pt/Ti/SiO2/Si substrate as a template. The effects of the solution concentration and Pt-assisted nucleation on the crystal growth and phase evolution were characterized by X-ray diffraction analysis and Raman spectroscopy. In addition, spin-coating technique was used for the fabrication of highly aligned nano-islands of β-glycine with regular orientation of the crystallographic axes relative the underlying substrate (Pt). Further we study both as-grown and tip-induced domain structures and polarization switching in the β-glycine molecular systems by Piezoresponse Force Microscopy (PFM) and compare the results with molecular modeling and computer simulations. We show that β-glycine is indeed a room-temperature ferroelectric and polarization can be switched by applying a bias to non-polar cuts via a conducting tip of atomic force microscope (AFM). Dynamics of these in-plane domains is studied as a function of applied voltage and pulse duration. The domain shape is dictated by both internal and external polarization screening mediated by defects and topographic features. Thermodynamic theory is applied to explain the domain propagation induced by the AFM tip. Our findings suggest that β-glycine is a uniaxial ferroelectric with the properties controlled by the charged domain walls which in turn can be manipulated by external bias. Besides, nonlinear optical properties of β-glycine were investigated by a second harmonic generation (SHG) method. SHG method confirmed that the 2-fold symmetry is preserved in as-grown crystals, thus reflecting the expected P21 symmetry of the β-phase. Spontaneous polarization direction is found to be parallel to the monoclinic [010] axis and directed along the crystal length. These data are confirmed by computational molecular modeling. Optical measurements revealed also relatively high values of the nonlinear optical susceptibility (50% greater than in the z-cut quartz). The potential of using stable β-glycine crystals in various applications are discussed in this work.

La rhétorique professionnelle des conseillers d'orientation pour l'accès à la pratique de la médiation familiale une image publique floue

Depuis le 1er septembre 1997, cinq professionnels ont accès à la pratique de la médiation familiale. Les conseillers d'orientation sont de ce nombre et ils sont les professionnels les moins bien représentés en médiation familiale et ce, à plusieurs points de vue. Ce mémoire pose l'hypothèse que les conseillers d'orientation ont de la difficulté à s'imposer dans cette pratique parce qu'ils ont un problème d'identité professionnelle qui les empêche de convaincre de leur pertinence en tant qu'intervenants. Balisé par un contexte théorique à caractère sociologique reposant sur les concepts de rhétorique professionnelle (Paradeise, 1985) et d'espace professionnel (Bourdon, 1994), les transcriptions des débats tenus en commission parlementaire sur la médiation familiale ont été analysés à l'aide d'une méthodologie qualitative. Il appert que les conseillers d'orientation n'ont su utiliser correctement les éléments de rhétorique professionnelle, et par surcroît, ils ont été les grandes victimes des tactiques utilisées par les autres acteurs.

Les TIC en information et orientation professionnelles un soutien au developpement de compétences transversales

À l'instar de la Réforme de l'éducation qui a lieu actuellement au Québec, deux éléments viennent alimenter le but et la raison d'être de cette recherche: l'abandon des cours de choix de carrière dans la grille-matière et le développement des compétences informatiques. Ces deux éléments relèvent des compétences transversales devant être construites par l'élève. L'objectif de cette recherche était de cerner l'efficacité du recours à des environnements informatiques en tant qu'outils de construction de compétences spécifiques et ainsi proposer aux jeunes une nouvelle méthode pour acquérir leur autonomie vocationnelle. L'échantillon était composé d'élèves de quatrième et cinquième secondaire. Suite aux traitements des données et aux analyses du discours des élèves, nos résultats démontrent comment les participants ont atteint certaines compétences transversales d'ordre méthodologiques et intellectuelles salutaires à leur choix de carrière. L'apport des technologies de l'information et des communications a été démontré et des pistes de recherches subséquentes ont été suggérées.

L'implication des parents dans l'orientation de leurs enfants

L'approche orientante qui est présentement implantée dans les écoles du Québec vise à favoriser l'implication des parents dans l'orientation de leurs enfants. La Suisse a pour sa part des méthodes qui répondent déjà à cet objectif. Afin de fournir une liste d'activités à privilégier pour la mise en oeuvre de l'approche orientante au Québec, 335 questionnaires ont été distribués à des parents du canton de Fribourg (Suisse). Ces derniers devaient indiquer les activités qui leur avaient été proposées au cours des études secondaires de leurs enfants, en plus de fournir leur degré de satisfaction à l'égard de celles-ci. Les résultats observés traduisent plusieurs suggestions d'activités permettant d'informer et d'impliquer davantage les parents dans l'orientation de leurs enfants.

Internalising the external costs of light goods vehicle transport in Britain

Report produced as part of the Green Logistics project (EPSRC and Department for Transport funded). To what extent do the taxes paid by the light goods vehicles (LGVs) users in Britain cover their allocated infrastructural, environmental and congestion costs? This report is a continuation of a study on the internalisation of the external costs of heavy goods vehicle activity. Research undertaken jointly by the Transport Studies Group at University of Westminster and Logistics Research Centre at Heriot-Watt University has attempted to answer this question using official government transport statistics and monetary valuations for the external costs.

Internalising the external costs of light and heavy goods vehicle transport in London

Report produced as part of the Green Logistics project (EPSRC and Department for Transport funded). This report provides estimates of the total external costs of LGV and HGV operations in London. In 2006, total LGV and HGV activity imposed external costs of approximately £1.75-£1.8 billion using low, medium and high emission cost values. About 27 per cent of these costs were internalised by duties and taxes paid by LGV operators, compared with 26% in the case of HGVs. If congestion costs are excluded, taxes and duties paid by LGV operators are estimated to be 155% of LGVs' allocated infrastructural and environmental costs, compared with 85% in the case of HGVs. When using the medium emission cost values, LGVs accounted for 56% of these external costs in London and HGVs for 44%.

Internalising the external costs of light and heavy goods vehicles in London

This report provides estimates of the total external costs of LGV and HGV operations in London. In 2006, total LGV and HGV activity imposed external costs of approximately £1.75-£1.8 billion using low, medium and high emission cost values. About 27 per cent of these costs were internalised by duties and taxes paid by LGV operators, compared with 26% in the case of HGVs. If congestion costs are excluded, taxes and duties paid by LGV operators are estimated to be 155% of LGVs' allocated infrastructural and environmental costs, compared with 85% in the case of HGVs. When using the medium emission cost values, LGVs accounted for 56% of these external costs in London and HGVs for 44%.

Internalising the external costs of light goods vehicle transport in Britain

To what extent do the taxes paid by the light goods vehicles (LGVs) users in Britain cover their allocated infrastructural, environmental and congestion costs? This report is a continuation of a study on the internalisation of the external costs of heavy goods vehicle activity. Research undertaken jointly by the Transport Studies Group at University of Westminster and Logistics Research Centre at Heriot-Watt University has attempted to answer this question using official government transport statistics and monetary valuations for the external costs.

Managing sales people strategically when promoting new products: Incorporating market orientation into a sales management control framework

Salespeople play a pivotal role in promoting new products. Therefore, managers need to know what control mechanism (i.e., output-based control, behavior-based control, or knowledge-based control) can improve their salespeople's new product sales performance. Furthermore, managers may be able to assist salespeople in performing better by having a strong market orientation. The literature has been inconsistent regarding the effects of sales management control mechanisms and has not yet incorporated market orientation into a sales management control framework. The current study surveyed 315 Taiwanese salespeople from publicly traded electronics companies with the aim of contributing to the sales management literature. The results show that sales management controls can directly affect salespeople's innovativeness, which, in turn, affects new product sales performance. However, sales management controls cannot affect performance directly. Furthermore, market orientation can positively moderate the relationship between salespeople's innovativeness and new product sales performance.

Revisiting the relationship between marketing capabilities and firm performance: The moderating role of market orientation, marketing strategy and organisational power

This paper extends original insights of resource-advantage theory (Hunt & Morgan, 1995) to a specific analysis of the moderators of the capabilities-performance relationship such as market orientation, marketing strategy and organizational power. Using established measures and a representative sample of UK firms drawn from Verhoef and Leeflang’s data (2009), our study tests new hypotheses to explain how different types of marketing capabilities contribute to firm performance. The application of resource-advantage theory advances theorising on both marketing and organisational antecedents of firm performance and the causal mechanisms by which competitive advantage is generated.

Avaliação dos ajustes posturais em indivíduos com instabilidade funcional do tornozelo

Introdução:O Controlo Postural é um processo neural complexo envolvido na organização da estabilidade e orientação da posição do corpo no espaço. A Instabilidade Funcional (IF) do tornozelo é descrita como uma perceção subjetiva de instabilidade articular, que afeta o controlo postural. Apesar de vários estudos terem investigado os fatores inerentes à IF ainda existe inconsistência nos resultados da literatura sobre os mecanismos envolvidos nesta. Objetivo (s):avaliar os ajustes posturais envolvidos na resposta a uma perturbação externa realizada de forma previsível e imprevisível em indivíduos com IF. Métodos:Estudo observacional analítico transversal, teve uma amostra de 20 indivíduos, que foram divididos em grupo com IF e grupo de controlo. Foi recolhida atividade eletromiográfica bilateral dos músculos longo e curto peroneal (PL e PC), tibial anterior (TA) e solear (SOL) associado a uma perturbação externa aplicada de forma previsível e imprevisível. Os ajustes posturais foram avaliados através da análise do início da atividade muscular, da magnitude global dos ajustes posturais compensatórios e antecipatórios e magnitude das respostas de curta e média latência Resultados: Na perturbação imprevisível não se verificaram diferenças significativas no início da atividade muscular (p>0,05). Enquanto na magnitude das respostas de curta e média latência verificou-se diferenças nos músculos TA (Ia,p=0,000; II, p=0,011), CP (Ia,p=0,029; II, p=0,001) e LP (Ia, p=0,030) entre o membro com IF e o controlo e no LP (II, p=0,011) entre o membro sem IF do grupo com IF e o controlo. Na perturbação previsível observaram-se diferenças nos ajustes posturais antecipatórios (APA) dos músculos TA (p=0,006) e LP (p=0,020) entre o membro sem IF do grupo com IF e o controlo. Conclusão: Os indivíduos com IF apresentam défices na magnitude das respostas de média e curta latência numa perturbação imprevisível e nos APA na perturbação previsível.

Influence of entrepreneurial orientation in export performance

This study aims at investigating the influence that entrepreneurial orientation has on export performance of Portuguese footwear small and mediumenterprises (SMEs). Therefore, a quantitative methodological approach was used, conducting a descriptive, exploratory and transversal empirical study, having applied a questionnaire to a sample of Portuguese companies exporting footwear. The research results suggest that entrepreneurial orientation enhances export performance in the analysed SMEs, particularly innovation and proactiveness, through the amount of funds invested, human resources dedicated to this activity, number of new products or services introduced in the market and frequent change in product lines or services and materialization of a long-term perspective, which is accompanied by innovative activities or new businesses. Therefore, the findings sustain the necessity to invest in entrepreneurial orientation as a strategic determinant, which contributes to the growth of small firms in foreignmarkets. Finally, the main limitation of this study is related to the sample size, since it was difficult to find companies willing to collaborate with this kind of research.

Non-assisted versus neuro-navigated and XperCT-guided external ventricular catheter placement: a comparative cadaver study.

BACKGROUND AND PURPOSE: Accurate placement of an external ventricular drain (EVD) for the treatment of hydrocephalus is of paramount importance for its functionality and in order to minimize morbidity and complications. The aim of this study was to compare two different drain insertion assistance tools with the traditional free-hand anatomical landmark method, and to measure efficacy, safety and precision. METHODS: Ten cadaver heads were prepared by opening large bone windows centered on Kocher's points on both sides. Nineteen physicians, divided in two groups (trainees and board certified neurosurgeons) performed EVD insertions. The target for the ventricular drain tip was the ipsilateral foramen of Monro. Each participant inserted the external ventricular catheter in three different ways: 1) free-hand by anatomical landmarks, 2) neuronavigation-assisted (NN), and 3) XperCT-guided (XCT). The number of ventricular hits and dangerous trajectories; time to proceed; radiation exposure of patients and physicians; distance of the catheter tip to target and size of deviations projected in the orthogonal plans were measured and compared. RESULTS: Insertion using XCT increased the probability of ventricular puncture from 69.2 to 90.2 % (p = 0.02). Non-assisted placements were significantly less precise (catheter tip to target distance 14.3 ± 7.4 mm versus 9.6 ± 7.2 mm, p = 0.0003). The insertion time to proceed increased from 3.04 ± 2.06 min. to 7.3 ± 3.6 min. (p < 0.001). The X-ray exposure for XCT was 32.23 mSv, but could be reduced to 13.9 mSv if patients were initially imaged in the hybrid-operating suite. No supplementary radiation exposure is needed for NN if patients are imaged according to a navigation protocol initially. CONCLUSION: This ex vivo study demonstrates a significantly improved accuracy and safety using either NN or XCT-assisted methods. Therefore, efforts should be undertaken to implement these new technologies into daily clinical practice. However, the accuracy versus urgency of an EVD placement has to be balanced, as the image-guided insertion technique will implicate a longer preparation time due to a specific image acquisition and trajectory planning.

Characteristics of infections associated with external ventricular drains of cerebrospinal fluid.

OBJECTIVES: Manifestations of external ventricular drain (EVD) - associated infections overlap with those of the underlying neurosurgical conditions. We analyzed characteristics of EVD-associated infections. METHODS: We included patients aged ≥18 years with EVD-associated infections from 1997 to 2008, using modified CDC criteria for nosocomial infections. Hospital charts were reviewed retrospectively and the in-hospital outcome was evaluated. RESULTS: Forty-eight patients with EVD-associated infections were included (median age, 52 years, range 20-74 years). The median EVD-indwelling time was 7 days (range, 1-39 days) and EVD-associated infection occurred 6 days after insertion (range, 1-17 days). In 23% of patients, meningitis occurred 1-10 days after EVD removal. Fever >38 °C was present in 79% of patients, but Glasgow Coma Scale (GCS) scores were reduced in only 29%, and headache, vomiting and/or neck stiffness were present in only 31%. The median cerebrospinal fluid (CSF) leukocyte count was higher at onset of EVD-associated infection than at EVD insertion (175 × 10(6)/l versus 46 × 10(6)/l, p = 0.021), but other CSF parameters did not differ significantly. The most commonly implicated organisms were coagulase-negative staphylococci (63%) and Propionibacterium acnes (15%). CONCLUSIONS: Fever and increased CSF leukocytes should raise the suspicion of EVD-associated infection, which may occur up to 10 days after removal of EVD.

PHYTOCHROME KINASE SUBSTRATE4 modulates phytochrome-mediated control of hypocotyl growth orientation

Gravity and light are major factors shaping plant growth. Light perceived by phytochromes leads to seedling deetiolation, which includes the deviation from vertical hypocotyl growth and promotes hypocotyl phototropism. These light responses enhance survival of young seedlings during their emergence from the soil. The PHYTOCHROME KINASE SUBSTRATE (PKS) family is composed of four members in Arabidopsis (Arabidopsis thaliana): PKS1 to PKS4. Here we show that PKS4 is a negative regulator of both phytochrome A- and B-mediated inhibition of hypocotyl growth and promotion of cotyledon unfolding. Most prominently, pks4 mutants show abnormal phytochrome-modulated hypocotyl growth orientation. In dark-grown seedlings hypocotyls change from the original orientation defined by seed position to the upright orientation defined by gravity and light reduces the magnitude of this shift. In older seedlings with the hypocotyls already oriented by gravity, light promotes the deviation from vertical orientation. Based on the characterization of pks4 mutants we propose that PKS4 inhibits changes in growth orientation under red or far-red light. Our data suggest that in these light conditions PKS4 acts as an inhibitor of asymmetric growth. This hypothesis is supported by the phenotype of PKS4 overexpressers. Together with previous findings, these results indicate that the PKS family plays important functions during light-regulated tropic growth responses