Text Segmentation Using Exponential Models

This paper introduces a new statistical approach to partitioning text automatically into coherent segments. Our approach enlists both short-range and long-range language models to help it sniff out likely sites of topic changes in text. To aid its search, the system consults a set of simple lexical hints it has learned to associate with the presence of boundaries through inspection of a large corpus of annotated data. We also propose a new probabilistically motivated error metric for use by the natural language processing and information retrieval communities, intended to supersede precision and recall for appraising segmentation algorithms. Qualitative assessment of our algorithm as well as evaluation using this new metric demonstrate the effectiveness of our approach in two very different domains, Wall Street Journal articles and the TDT Corpus, a collection of newswire articles and broadcast news transcripts.Comment: 12 pages, LaTeX source and postscript figures for EMNLP-2 pape

Suppression of Supergravity Anomalies in Conformal Sequestering

We show that the anomaly-mediated supersymmetry breaking via the Kahler and sigma-model anomalies is suppressed by conformal dynamics in the supersymmetry breaking sector.Comment: 8 page

Detection of Radio Emission from the Hyperactive L Dwarf 2MASS J13153094-2649513AB

We report the detection of radio emission from the unusually active L5e + T7 binary 2MASS J13153094-2649513AB made with the Australian Telescope Compact Array. Observations at 5.5 GHz reveal an unresolved source with a continuum flux of 370+/-50 microJy, corresponding to a radio luminosity of L_rad = nuL_nu = (9+/-3)x10^23 erg/s and log10(L_rad/L_bol) = -5.44+/-0.22. No detection is made at 9.0 GHz to a 5 sigma limit of 290 microJy, consistent with a power law spectrum S_nu ~ nu^-a with a > 0.5. The emission is quiescent, with no evidence of variability or bursts over 3 hr of observation, and no measurable polarization (V/I < 34%). 2MASS J1315-2649AB is one of the most radio-luminous ultracool dwarfs detected in quiescent emission to date, comparable in strength to other cool sources detected in outburst. Its detection indicates no decline in radio flux through the mid-L dwarfs. It is unique among L dwarfs in having strong and persistent Halpha and radio emission, indicating the coexistence of a cool, neutral photosphere (low electron density) and a highly active chromosphere (high electron density and active heating). These traits, coupled with the system's mature age and substellar secondary, makes 2MASS J1315-2649AB an important test for proposed radio emission mechanisms in ultracool dwarfs.Comment: 5 pages, 4 figures, accepted for publication in ApJ Letter

A novel experiment searching for the lepton flavour violating decay mu -> eee

Since the discovery of neutrino oscillations it is known that lepton flavour is not conserved. Lepton flavour violating processes in the charged lepton sector have so far however eluded detection; as they are heavily suppressed in the standard model of particle physics, an observation would be a clear signal for new physics and help to understand the source of neutrino masses and CP violation. We propose a novel experiment searching for the decay mu -> eee with the aim of ultimately reaching a sensitivity of 10^-16, an improvement by four orders of magnitude compared to previous experiments. The technologies enabling this step are thin high-voltage monolithic active pixel sensors for precise tracking at high rates with a minimum of material and scintillating fibres for high resolution time measurements.Comment: 4 pages, 3 figures, contribution to NUFACT 11, XIIIth International Workshop on Neutrino Factories, Super beams and Beta beams, 1-6 August 2011, CERN and University of Genev

Asynchronous Monad for Reactive IoT Programming

The widespread adoption of Internet of Things (IoT) has given rise to systems which must reactively process signal data, while maintaining latency and throughput constraints. While the reactive programming paradigm partially addresses this problem, it does not offer a complete solution. We propose a design for a monad, AsyncM, and apply it to implement push-pull functional reactive programming (FRP) where side-effect bound events are performed in low-latency push streams, and time-series computations are performed in demand-driven pull streams. The design uses implicitly threaded cancellation tokens and continuation passing style to allow for implementations in languages which have single-threaded event-loops as well as languages which have multi-threading. We present our abstractions Stream, Signal, and Behavior and their functor, applicative, and (when applicable) monadic instances. We demonstrate how push streams (Stream) can be converted to pull streams (Signal) (and visa versa) to apply our model to practical use cases. We give a use case of a real-time IoT data analytics platform to demonstrate our design\u27s industrial significance where signal sample rates can change dynamically based on unknown factors such as network speed and processor resources. Application of the design to dynamic languages is shown throughout the paper in a reference JavaScript implementation

Surgical approaches to adenocarcinoma of the gastroesophageal junction: the Siewert II conundrum.

BACKGROUND: The Siewert classification system for gastroesophageal junction adenocarcinoma has provided morphological and topographical information to help guide surgical decision-making. Evidence has shown that Siewert I and III tumors are distinct entities with differing epidemiologic and histologic characteristics and distinct patterns of disease progression, requiring different treatment. Siewert II tumors share some of the characteristics of type I and III lesions, and the surgical approach is not universally agreed upon. Appropriate surgical options include transthoracic esophagogastrectomy, transhiatal esophagectomy, and transabdominal extended total gastrectomy. PURPOSE: A review of the available evidence of the surgical management of Siewert II tumors is presented. CONCLUSIONS: Careful review of the data appear to support the fact that a satisfactory oncologic resection can be achieved via a transabdominal extended total gastrectomy with a slight advantage in terms of perioperative complications, and overall postoperative quality of life. Overall and disease-free survival compares favorably to the transthoracic approach. These results can be achieved with careful selection of patients balancing more than just the Siewert type in the decision-making but considering also preoperative T and N stages, histological type (diffuse type requiring longer margins that are not always achievable via gastrectomy), and the presence of Barrett\u27s esophagus

Designing Materials and Processes for CO2 Capture with Solid Sorbents

Cyclic adsorption and regeneration of solid sorbents to remove CO2 from gas streams can be accomplished with a variety of different adsorbents and processes. Determining which adsorbents and which processes will be best suited for a given application requires simulations or experimental measurements of many different materials in many different processes. However, general principles can guide the development of carbon capture systems, based primarily on the performance and limitations of different adsorbents, types of gas-solid contactors used, heat exchange method, and managing pressure changes. The main types of adsorption processes are temperature swing, pressure swing, or a combined temperature and pressure swing. Temperature swing adsorption processes involve regenerating a sorbent saturated with CO2 through heating. In these processes heat transfer is generally the rate-limiting step and heating and cooling the sorbent is also the most energy intensive component of the process. To minimize the energy consumption of the process, the sorbent should have a moderate heat of adsorption to allow a large change in CO2 capacity through changing the temperature, the heat capacity of the heated and cooled material should be minimized, and heat transfer should be maximized. For pressure swing adsorption processes, on the other hand, the driving force for regenerating CO2 is provided by changing the partial pressure of CO2 between the adsorption and regeneration steps. Changing the pressure is the main component of the energy consumption and cycle time, and these are minimized by allowing complex process configurations with multiple pressure differentials and using an adsorbent with high capacity but low heat of adsorption. Combined temperature and pressure swing adsorption can be optimized through a combination of the factors above. Each of these cases yields a different optimal material, contacting strategy, and process configuration, but all can be approached using a common design methodology. This paper will present a design methodology for solid sorbent CCS systems. This will include design considerations for how to maximize the performance of a range of traditionally deployed and newly-discovered solid sorbents. Similarly, standard and novel process configurations will be discussed with descriptions of the possible benefits or drawbacks and the types of sorbent material that are best suited for each configuration. By comparing the performance of mature adsorbents and processes and the expected performance of adsorbents and processes currently under development, the state of the art and potential advances for CCS with solid adsorbents will be presented