6,065 research outputs found
StarSpace: Embed All The Things!
We present StarSpace, a general-purpose neural embedding model that can solve
a wide variety of problems: labeling tasks such as text classification, ranking
tasks such as information retrieval/web search, collaborative filtering-based
or content-based recommendation, embedding of multi-relational graphs, and
learning word, sentence or document level embeddings. In each case the model
works by embedding those entities comprised of discrete features and comparing
them against each other -- learning similarities dependent on the task.
Empirical results on a number of tasks show that StarSpace is highly
competitive with existing methods, whilst also being generally applicable to
new cases where those methods are not
Are global wind power resource estimates overstated?
Estimates of the global wind power resource over land range from 56 to 400 TW. Most estimates have implicitly assumed that extraction of wind energy does not alter large-scale winds enough to significantly limit wind power production. Estimates that ignore the effect of wind turbine drag on local winds have assumed that wind power production of 2–4 W m2 can be sustained over large areas. New results from a mesoscale model suggest that wind power production is limited to about 1 W m2 at wind farm scales larger than about 100 km2. We find that the mesoscale model results are quantitatively consistent with results from global models that simulated the climate response to much larger wind power capacities. Wind resource estimates that ignore the effect of wind turbines in slowing large-scale winds may therefore substantially overestimate the wind power resource.Engineering and Applied Science
Genes Duplicated by Polyploidy Show Unequal Contributions to the Transcriptome and Organ-Specific Reciprocal Silencing
Most eukaryotes have genomes that exhibit high levels of gene redundancy, much of which seems to have arisen from one or more cycles of genome doubling. Polyploidy has been particularly prominent during flowering plant evolution, yielding duplicated genes (homoeologs) whose expression may be retained or lost either as an immediate consequence of polyploidization or on an evolutionary timescale. Expression of 40 homoeologous gene pairs was assayed by cDNA-single-stranded conformation polymorphism in natural (1- to 2-million-yr-old) and synthetic tetraploid cotton (Gossypium) to determine whether homoeologous gene pairs are expressed at equal levels after polyploid formation. Silencing or unequal expression of one homoeolog was documented for 10 of 40 genes examined in ovules of Gossypium hirsutum. Assays of homoeolog expression in 10 organs revealed variable expression levels and silencing, depending on the gene and organ examined. Remarkably, silencing and biased expression of some gene pairs are reciprocal and developmentally regulated, with one homoeolog showing silencing in some organs and the other being silenced in other organs, suggesting rapid subfunctionalization. Duplicate gene expression was examined in additional natural polyploids to characterize the pace at which expression alteration evolves. Analysis of a synthetic tetraploid revealed homoeolog expression and silencing patterns that sometimes mirrored those of the natural tetraploid. Both long-term and immediate responses to polyploidization were implicated. Data suggest that some silencing events are epigenetically induced during the allopolyploidization process
Eulerian-Lagrangian analysis of pollutant transport in shallow water
A numerical method for the solution of the two-dimensional, unsteady, transport equation is formulated, and its accuracy is tested.The method uses a Eulerian-Lagrangian approach, in which the transport equation is divided into a diffusion equation (solved by a finite element method) and a convection equation (solved by the method of characteristics). This approach leads to results that are free of spurious oscillations and excessive numerical damping, even in the case where advection strongly dominates diffusion. For pure diffusion problems, optimal accuracy is approached as the time-step, At, goes to zero; conversely, for pure-convection problems, accuracy improves with increasing At; for convection-diffusion problems the At leading to optimal accuracy depends on the characteristics of the spatial discretization and on the relative importance of convection and diffusion.The method is cost-effective in modeling pollutant transport in coastal waters, as demonstrated by two prototype applications: hypothetical sludge dumping in Massachusetts Bay and the thermal discharge from Brayton Point Generating Station in Narragansett Bay. Numerical diffusion is eliminated or greatly reduced, raising the need for realistic estimation of dispersion coefficients. Costs (based on CPU time) should not exceed those of conventional Eulerian methods and, in some cases (e.g., problems involving predictions over several tidal cycles), considerable savings may even be achieved
Fracture toughness of the cancellous bone of FNF femoral heads in relation to its microarchitecture
This study considers the relationship between microarchitecture and mechanical properties for cancellous bone specimens collected from a cohort of patients who had suffered fractured necks of femur. OP
is an acute skeletal condition with huge socioeconomic impact [1] and it is associated with changes in both bone quantity and quality [2], which affect greatly the strength and toughness of the tissue [3].Support was provided by the EPSRC (EP/K020196: Point-ofCare High Accuracy Fracture Risk Prediction), the UK Department of Transport under the BOSCOS (Bone Scanning for Occupant Safety) project, and approved by Gloucester and Cheltenham NHS Trust hospitals under ethical consent (BOSCOS – Mr. Curwen CI REC ref 01/179G)
We are Designers Because We Can Abstract
Organised by: Cranfield UniversityDue to the increasing systems complexity, architecture design became an important issue. It gained
interest and its importance was framed in three domains: as a way to understand complex systems, to
design them, to manage their manufacturing process and to provide long-term rationality. The purpose of
this paper is, firstly, to survey the existing definition approaches on architecture. Secondly, we propose a
model for architecture design which articulates the potential linkage between two principle concepts:
synthesis and abstraction. Our proposal model focuses on abstraction concept and permits an effective
top-down design approach. It helps also designers to more respond to issues that characterize architecture
design.Mori Seiki – The Machine Tool Compan
Polarized nuclear target based on parahydrogen induced polarization
We discuss a novel concept of a polarized nuclear target for accelerator
fixed-target scattering experiments, which is based on parahydrogen induced
polarization (PHIP). One may be able to reach a 33% free-proton polarization in
the ethane molecule. The potential advantages of such a target include
operation at zero magnetic field, fast (100 Hz) polarization reversal,
and operation with large intensity of an electron beam.Comment: 16 pages, 2 figure
Bubbles Unbound: Bubbles of Nothing Without Kaluza-Klein
I present analytic time symmetric initial data for five dimensions describing
``bubbles of nothing'' which are asymptotically flat in the higher dimensional
sense, i.e. there is no Kaluza-Klein circle asymptotically. The mass and size
of these bubbles may be chosen arbitrarily and in particular the solutions
contain bubbles of any size which are arbitrarily light. This suggests the
solutions may be important phenomenologically and in particular I show that at
low energy there are bubbles which expand outwards, suggesting a new possible
instability in higher dimensions. Further, one may find bubbles of any size
where the only region of high curvature is confined to an arbitrarily small
volume.Comment: 27 pages, 2 figures, v2: minor changes, published versio
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