629 research outputs found

    Does the continuum theory of dynamic fracture work?

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    We investigate the validity of the Linear Elastic Fracture Mechanics approach to dynamic fracture. We first test the predictions in a lattice simulation, using a formula of Eshelby for the time-dependent Stress Intensity Factor. Excellent agreement with the theory is found. We then use the same method to analyze the experiment of Sharon and Fineberg. The data here is not consistent with the theoretical expectation.Comment: 4 page

    Ground-state properties of rutile: electron-correlation effects

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    Electron-correlation effects on cohesive energy, lattice constant and bulk compressibility of rutile are calculated using an ab-initio scheme. A competition between the two groups of partially covalent Ti-O bonds is the reason that the correlation energy does not change linearly with deviations from the equilibrium geometry, but is dominated by quadratic terms instead. As a consequence, the Hartree-Fock lattice constants are close to the experimental ones, while the compressibility is strongly renormalized by electronic correlations.Comment: 1 figure to appear in Phys. Rev.

    Correlation effects in MgO and CaO: Cohesive energies and lattice constants

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    A recently proposed computational scheme based on local increments has been applied to the calculation of correlation contributions to the cohesive energy of the CaO crystal. Using ab-initio quantum chemical methods for evaluating individual increments, we obtain 80% of the difference between the experimental and Hartree-Fock cohesive energies. Lattice constants corrected for correlation effects deviate by less than 1% from experimental values, in the case of MgO and CaO.Comment: LaTeX, 4 figure

    CoCREATE: Collaborative Curriculum Reimagining and Enhancement Aiming to Transform Education

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    The establishment of TU Dublin in January 2019 provided a unique opportunity to create a bespoke curriculum framework for students, staff and stakeholders of TU Dublin, produced by the students, staff and stakeholders of TU Dublin. A curriculum framework is a set of guiding values that inform the design of teaching and learning activities within TU Dublin. A Teaching Fellowship Team, comprising eighteen teaching academics from across the three TU Dublin campuses and supported extensively by the Learning Teaching and Technology Centre (LTTC), was formed to collaboratively craft, in partnership with all stakeholders, a curriculum framework for TU Dublin. Working collaboratively under the project name CoCREATE (Collaborative Curriculum Reimagining and Enhancement Aiming to Transform Education) the Teaching Fellowship Team developed TU Dublin’s CoCREATED Curriculum Framework over eighteen months. The design and development of the CoCREATED Curriculum Framework was informed by consultation with all key stakeholders across all campuses, examination and synthesis of local, national and international best practice and policy, as well as relevant scholarly literature. The framework is underpinned by the core values and mission of TU Dublin, as well as local and national strategic plans. It provides a distinctive but tangible learning philosophy for all at TU Dublin. The framework is both considered, flexible and progressive so as to adapt to the diversity within TU Dublin, including accredited programmes, and is inclusive of all learners across the university. The four curriculum values of the TU Dublin CoCREATED Curriculum Framework are: Step forward and try new things Use all of our talents; everyone has something to learn and something to teach Make our learning experience active, useful and related to the world Create the space and time to do work that matters This new, dynamic and evolving TU Dublin CoCREATED Curriculum Framework characterises an innovative, responsive and caring learning environment for the diversity of our university’s student population across all programme levels. Simultaneously, it developed a synergy between staff, students, professional bodies, industry and community partners through a collaborative design process. It is as inspiring, distinctive and pioneering as Ireland’s first Technological University. The CoCREATED Curriculum Framework will support staff and students to develop a unique approach to teaching and learning, which will characterise a TU Dublin teaching and learning experience, and ultimately a TU Dublin graduate, in a competitive national and international higher education space. Going forward, the TU Dublin CoCREATED Curriculum Framework will empower the judicious creation of rich and diverse curricula across all disciplines and levels within TU Dublin, from apprenticeship, through undergraduate, to structured PhD

    Intermediate and extreme mass-ratio inspirals — astrophysics, science applications and detection using LISA

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    Black hole binaries with extreme (gtrsim104:1) or intermediate (~102–104:1) mass ratios are among the most interesting gravitational wave sources that are expected to be detected by the proposed laser interferometer space antenna (LISA). These sources have the potential to tell us much about astrophysics, but are also of unique importance for testing aspects of the general theory of relativity in the strong field regime. Here we discuss these sources from the perspectives of astrophysics, data analysis and applications to testing general relativity, providing both a description of the current state of knowledge and an outline of some of the outstanding questions that still need to be addressed. This review grew out of discussions at a workshop in September 2006 hosted by the Albert Einstein Institute in Golm, Germany

    Inscribing a discipline: tensions in the field of bioinformatics

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    Bioinformatics, the application of computer science to biological problems, is a central feature of post-genomic science which grew rapidly during the 1990s and 2000s. Post-genomic science is often high-throughput, involving the mass production of inscriptions [Latour and Woolgar (1986), Laboratory Life: the Construction of Scientific Facts. Princeton, NJ: Princeton University Press]. In order to render these mass inscriptions comprehensible, bioinformatic techniques are employed, with bioinformaticians producing what we call secondary inscriptions. However, despite bioinformaticians being highly skilled and credentialed scientists, the field struggles to develop disciplinary coherence. This paper describes two tensions militating against disciplinary coherence. The first arises from the fact that bioinformaticians as producers of secondary inscriptions are often institutionally dependent, subordinate even, to biologists. With bioinformatics positioned as service, it cannot determine its own boundaries but has them imposed from the outside. The second tension is a result of the interdisciplinary origin of bioinformatics – computer science and biology are disciplines with very different cultures, values and products. The paper uses interview data from two different UK projects to describe and examine these tensions by commenting on Calvert's [(2010) “Systems Biology, Interdisciplinarity and Disciplinary Identity.” In Collaboration in the New Life Sciences, edited by J. N. Parker, N. Vermeulen and B. Penders, 201–219. Farnham: Ashgate] notion of individual and collaborative interdisciplinarity and McNally's [(2008) “Sociomics: CESAGen Multidisciplinary Workshop on the Transformation of Knowledge Production in the Biosciences, and its Consequences.” Proteomics 8: 222–224] distinction between “black box optimists” and “black box pessimists.

    Fresh takes on five health data sharing domains: Quality, privacy, equity, incentives, and sustainability

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    As entities around the world invest in repositories and other infrastructure to facilitate health data sharing, scalable solutions to data sharing challenges are needed. We conducted semi-structured interviews with 24 experts to explore views on potential issues and policy options related to health data sharing. In this Perspective, we describe and contextualize unconventional insights shared by our interviewees relevant to issues in five domains: data quality, privacy, equity, incentives, and sustainability. These insights question a focus on granular quality metrics for gatekeeping; challenge enthusiasm for maximalist risk disclosure practices; call attention to power dynamics that potentially compromise the patient's voice; encourage faith in the sharing proclivities of new generations of scientists; and endorse accounting for personal disposition in the selection of long-term partners. We consider the merits of each insight with the broad goal of encouraging creative thinking to address data sharing challenges

    Directed Self-Assembly: Expectations and Achievements

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    Nanotechnology has been a revolutionary thrust in recent years of development of science and technology for its broad appeal for employing a novel idea for relevant technological applications in particular and for mass-scale production and marketing as common man commodity in general. An interesting aspect of this emergent technology is that it involves scientific research community and relevant industries alike. Top–down and bottom–up approaches are two broad division of production of nanoscale materials in general. However, both the approaches have their own limits as far as large-scale production and cost involved are concerned. Therefore, novel new techniques are desired to be developed to optimize production and cost. Directed self-assembly seems to be a promising technique in this regard; which can work as a bridge between the top–down and bottom–up approaches. This article reviews how directed self-assembly as a technique has grown up and outlines its future prospects

    Temporal and spatial variability in stable isotope ratios of SPM link to local hydrography and longer term SPM averages suggest heavy dependence of mussels on nearshore production

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    Temporal changes in hydrography affect suspended particulate matter (SPM) composition and distribution in coastal systems, potentially influencing the diets of suspension feeders. Temporal variation in SPM and in the diet of the mussel Perna perna, were investigated using stable isotope analysis. The δ13C and δ15 N ratios of SPM, mussels and macroalgae were determined monthly, with SPM samples collected along a 10 km onshore–offshore transect, over 14 months at Kenton-on-Sea, on the south coast of South Africa. Clear nearshore (0 km) to offshore (10 km) carbon depletion gradients were seen in SPM during all months and extended for 50 km offshore on one occasion. Carbon enrichment of coastal SPM in winter (June–August 2004 and May 2005) indicated temporal changes in the nearshore detrital pool, presumably reflecting changes in macroalgal detritus, linked to local changes in coastal hydrography and algal seasonality. Nitrogen patterns were less clear, with SPM enrichment seen between July and October 2004 from 0 to 10 km. Nearshore SPM demonstrated cyclical patterns in carbon over 24-h periods that correlated closely with tidal cycles and mussel carbon signatures, sampled monthly, demonstrated fluctuations that could not be correlated to seasonal or monthly changes in SPM. Macroalgae showed extreme variability in isotopic signatures, with no discernable patterns. IsoSource mixing models indicated over 50% reliance of mussel tissue on nearshore carbon, highlighting the importance of nearshore SPM in mussel diet. Overall, carbon variation in SPM at both large and small temporal scales can be related to hydrographic processes, but is masked in mussels by long-term isotope integration
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