104 research outputs found

    A fibre forming smectic twist-bent liquid crystalline phase

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    We demonstrate the nanostructure and filament formation of a novel liquid crystal phase of a dimeric mesogen below the twist–bend nematic phase. The new fibre-forming phase is distinguished by a short-correlated smectic order combined with an additional nanoscale periodicity that is not associated with density modulation

    Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field

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    We have determined the nematic-isotropic transition temperature as a function of applied magnetic field in three different thermotropic liquid crystalline dimers. These molecules are comprised of two rigid calamitic moieties joined end to end by flexible spacers with odd numbers of methylene groups. They show an unprecedented magnetic field enhancement of nematic order in that the transition temperature is increased by up to 15K when subjected to 22T magnetic field. The increase is conjectured to be caused by a magnetic field-induced decrease of the average bend angle in the aliphatic spacers connecting the rigid mesogenic units of the dimers

    Between Negotiations and Litigation: Vanuatu’s Perspective on Loss and Damage from Climate Change

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    This contribution explores how climate-vulnerable states can effectively use the law to force action in order to address loss and damage from climate change, taking the Pacific Island state of Vanuatu as an example. Vanuatu made headlines when its Minister of Foreign Affairs, International Cooperation and External Trade, the Hon. Ralph Regenvanu, announced his government’s intention to explore legal action as a tool to address climate loss and damage suffered in Vanuatu. Our contribution places this announcement in the context of Vanuatu’s own experience with climate loss and damage, and the state’s ongoing efforts to secure compensation for loss and damage through the multilateral climate change regime. We then discuss the possibilities for legal action to seek redress for climate loss and damage, focusing on two types of action highlighted in Minister Regenvanu’s statement: action against states under international law, and action against fossil fuel companies under domestic law. After concluding that the issue of compensation for climate loss and damage is best addressed at the multilateral level, we offer proposals on how the two processes of litigation and negotiation could interact with each other and inspire more far-reaching action to address loss and damage from climate change.NWO016.Veni.195.342Exploring the Frontiers of International La

    Magnetically tunable selective reflection of light by heliconical cholesterics

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    This work was financially supported by NSF DMR-1307674, NSF Grant No. DMR-1410378, and AFOSR (Grant No. FA9550-12-1-0037). The work utilized the facilities of the NHMFL, which is supported by NSF DMR-0084173, the State of Florida, and the U.S. Department of Energy.Peer reviewedPublisher PD

    Classifying organisms and artefacts by their outline shapes

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    We often wish to classify objects by their shapes. Indeed, the study of shapes is an important part of many scientific fields, such as evolutionary biology, structural biology, image processing and archaeology. However, mathematical shape spaces are rather complicated and nonlinear. The most widely used methods of shape analysis, geometric morphometrics, treat the shapes as sets of points. Diffeomorphic methods consider the underlying curve rather than points, but have rarely been applied to real-world problems. Using a machine classifier, we tested the ability of several of these methods to describe and classify the shapes of a variety of organic and man-made objects. We find that one method, based on square-root velocity functions (SRVFs), outperforms all others, including a standard geometric morphometric method (eigenshapes), and that it is also superior to human experts using shape alone. When the SRVF approach is constrained to take account of homologous landmarks it can accurately classify objects of very different shapes. The SRVF method identifies a shortest path between shapes, and we show that this can be used to estimate the shapes of intermediate steps in evolutionary series. Diffeomorphic shape analysis methods, we conclude, now provide practical and effective solutions to many shape description and classification problems in the natural and human sciences.</p

    Cross-Cultural Validation of the Inventory of School Motivation (ISM) in the Asian Setting: Hong Kong and the Philippines

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    Students’ achievement goals in school have received increasing research attention because they have been shown to be important in predicting important outcomes. As such, there has been a growing interest in measuring and comparing them across different cultural groups. However, these comparisons cannot be made until validity evidence has been attained to support the use of an instrument in the new cultural setting. In this study, we investigated the cross-cultural applicability of the Inventory of School Motivation (ISM, McInerney et al. American Educational Research Journal 34:207-236, 1997) in the Hong Kong Chinese and Philippine contexts using both within-network and between-network approaches to construct validation. The ISM measures four types of achievement goals: mastery, performance, social, and extrinsic goals. 1,406 high school students from Hong Kong (n = 697) and the Philippines (n = 709) participated. Results of the within-network test showed that the ISM had good internal consistency reliability and the confirmatory factor analysis provided support for the hypothesized four-factor model. Multigroup confirmatory factor analyses supported invariance of factor loadings across the two samples. The between-network test also indicated that these achievement goals correlated systematically with different aspects of students’ self-concepts. These findings support the applicability of the ISM among Hong Kong Chinese and Filipino students

    Policy Brief 2: Building Community Resilience

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    Building resilience in Ocean Cities of the Pacific region is key to converting challenges and risks communities face into opportunities for systemic transformation toward sustainable development. Island settlements at the nexus of ocean health, climate change and urban development will need to build anticipatory, adaptive, absorptive and transformative capacity in the face of complex stressors. The interlinked challenges and resource constraints in rapidly growing Ocean Cities in the Pacific means that the ability to absorb shocks and bounce back relevant partners and stakeholders to promote equitable opportunities for all people in urban communities to access resources and use them sustainably, and to apply standardized methods contextualized for the Pacific to assess the relative vulnerability of communities in Ocean Cities. It also recognizes the importance of promoting stronger governance regimes within urban communities, aligning these with the policies of local government, and encouraging partnerships between urban and rural communities. This second policy brief in the Ocean Cities series offers guidance in this direction

    Researching shadow education: Methodological challenges and directions

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    Research on shadow education has considerably increased in volume and has helped to improve understanding of the scale, nature, and implications of the phenomenon. However, the field is still in its infancy. Literature on shadow education reflects confusion over terms and parameters, and data suffer from challenges in securing evidence from actors who may be unwilling or unable to respond to enquiries in a clear manner. Particular care is needed in cross-national and cross-cultural comparisons. Nevertheless, the trajectory of improvement in both conceptualisation and instrumentation gives ground for confidence that shadow education will be progressively better documented and better understood. © Education Research Institute, Seoul National University, Seoul, Korea 2010.published_or_final_versionSpringer Open Choice, 01 Dec 201

    Combined Microscopy, Calorimetry and X-ray Scattering Study of Fluorinated Dimesogens

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    The material FDO11DFCB3 (compound 2 in this work) remains the only example of a liquid-crystalline material to exhibit a phase transition from the heliconical twist-bend phase into a lamellar smectic A mesophase, additionally this material exhibits a previously unidentified mesophase. We have prepared and characterised several homologues of this compound, with each material subjected to an in-depth analysis by optical microscopy, calorimetry and small angle X-ray scattering studies. Despite FDO11DFCB3 being similar in chemical structure to the novel materials presented herein its liquid-crystalline behaviour is rather different, indicating an unexpected sensitivity of the twist-bend phase to molecular structure
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