Testing the Limits of Anaphoric Distance in Classical Arabic: a Corpus-Based Study

One of the central aims in research on anaphora is to discover the factors that determine the choice of referential expressions in discourse. Ariel (1988; 2001) offers an Accessibility Scale where referential expressions, including demonstratives, are categorized according to the values of anaphoric (i.e. textual) distance that each of these has in relation to its antecedent. The aim of this paper is to test Ariel’s (1988; 1990; 2001) claim that the choice to use proximal or distal anaphors is mainly determined by anaphoric distance. This claim is investigated in relation to singular demonstratives in a corpus of Classical Arabic (CA) prose texts by using word count to measure anaphoric distance. Results indicate that anaphoric distance cannot be taken as a consistent or reliable determinant of how anaphors are used in CA, and so Ariel’s claim is not supported by the results of this study. This also indicates that the universality of anaphoric distance, as a criterion of accessibility, is defied

Bounds on Scalar Masses in Theories of Moduli Stabilization

In recent years it has been realised that pre-BBN decays of moduli can be a significant source of dark matter production, giving a `non-thermal WIMP miracle' and substantially reduced fine-tuning in cosmological axion physics. We study moduli masses and sharpen the claim that moduli dominated the pre-BBN Universe. We conjecture that in any string theory with stabilized moduli there will be at least one modulus field whose mass is of order (or less than) the gravitino mass. Cosmology then generically requires the gravitino mass not be less than about 30 TeV and the cosmological history of the Universe is non-thermal prior to BBN. Stable LSP's produced in these decays can account for the observed dark matter if they are `wino-like.' We briefly consider implications for the LHC, rare decays, and dark matter direct detection and point out that these results could prove challenging for models attempting to realize gauge mediation in string theory.Comment: 7 pages. v3: published versio

On the Cost of Essentially Fair Clusterings

Clustering is a fundamental tool in data mining. It partitions points into groups (clusters) and may be used to make decisions for each point based on its group. However, this process may harm protected (minority) classes if the clustering algorithm does not adequately represent them in desirable clusters -- especially if the data is already biased. At NIPS 2017, Chierichetti et al. proposed a model for fair clustering requiring the representation in each cluster to (approximately) preserve the global fraction of each protected class. Restricting to two protected classes, they developed both a 4-approximation for the fair $k$-center problem and a $O(t)$-approximation for the fair $k$-median problem, where $t$ is a parameter for the fairness model. For multiple protected classes, the best known result is a 14-approximation for fair $k$-center. We extend and improve the known results. Firstly, we give a 5-approximation for the fair $k$-center problem with multiple protected classes. Secondly, we propose a relaxed fairness notion under which we can give bicriteria constant-factor approximations for all of the classical clustering objectives $k$-center, $k$-supplier, $k$-median, $k$-means and facility location. The latter approximations are achieved by a framework that takes an arbitrary existing unfair (integral) solution and a fair (fractional) LP solution and combines them into an essentially fair clustering with a weakly supervised rounding scheme. In this way, a fair clustering can be established belatedly, in a situation where the centers are already fixed

Pull-out behavior of post installed rebar connections using chemical adhesives and cement based binders

This study investigated the effectiveness of several types of adhesives used in post-installed rebar connections as a bonding agent between steel reinforcement bars and old concrete under pull-out test. The cylindrical samples (96 + 24 Nos) of 15 dia. × 30 cm with anchors rebar of varying diameter (8, 10, 12 mm) with different embedded length (10, 15 and 20 × rebar diameter). The control (24 Nos) was the cast in-place rebar concrete specimens while other samples (96 Nos) were post rebar-installed concrete specimen of varied bonding agents-chemical adhesives (Sikadure-31CF and EPICHOR 1786) or cement-based binders (mortar, ultra-high performance self-compacting concrete (UHPSCC). The findings showed that the use of the adhesives and UHPCC pull-out load values were in close proximity while they all outperformed mortar bonded specimens. The pull-out load (bond strength) increases with

Microstructure and tensile properties of friction stir processed Al-Si alloy

In this study, a solid state processing tool for microstructure modification and material properties enhancement; friction stir processing (FSP) was applied on the surface of as-cast Al-Si-Cu-Ni aluminium alloy. Samples were subjected to FSP using fixed tool rotation speed 1400 rpm and traverse speed 42 mm/min, with tool angle tilted 3˚.The influence of the FSP on the microstructure and tensile properties of the cast AlSi-Cu-Ni alloy samples were studied. Microstructural evolution of the samples was investigated using optical microscope (OM) and scanning electron microscope (SEM), tensile test carried out at 1 mm/min cross-head speed. The results showed that FSP improved the tensile strength of the samples by decreasing particles size and porosity. FSP improved the alloy strength by about 54%

Pilot scale hybrid fed batch and continuous processing of biologics

Pfizer Bioprocessing R&D is focused on developing enabling technologies that will reduce capital and operational expenses, decrease equipment scale, increase automation and utilize fewer FTEs. To realize this vision, our Pilot Facility has partnered with our cell culture process development colleagues to adapt a fed batch platform 150L stainless steel bioreactor to run in hybrid perfusion, standard perfusion, low volume cell controlled perfusion, and continuous stirred tank modes. Through adjustments to impeller configuration, sparging strategy, and addition ports the bioreactor was able to deliver multiple batches that produced ~3X gains in cell density and volumetric productivity versus conventional fed batch platform methods

The information paradox: conflicts and resolutions

Many relativists have been long convinced that black hole evaporation leads to information loss or remnants. String theorists have however not been too worried about the issue, largely due to a belief that the Hawking argument for information loss is flawed in its details. A recently derived inequality shows that the Hawking argument for black holes with horizon can in fact be made rigorous. What happens instead is that in string theory black hole microstates have no horizons. Thus the evolution of radiation quanta with E ~ kT is modified by order unity at the horizon, and we resolve the information paradox. We discuss how it is still possible for E >> kT objects to see an approximate black hole like geometry. We also note some possible implications of this physics for the early Universe.Comment: 26 pages, 8 figures, Latex; (Expanded version of) proceedings for Lepton-Photon 201

Missed opportunities: Racial and neighborhood socioeconomic disparities in emergency colorectal cancer diagnosis and surgery

BackgroundDisparities by race and neighborhood socioeconomic status exist for many colorectal cancer (CRC) outcomes, including screening use and mortality. We used population-based data to determine if disparities also exist for emergency CRC diagnosis and surgery.MethodsWe examined two emergency CRC outcomes using 1992-2005 population-based U.S. SEER-Medicare data. Among CRC patients aged ≥66 years, we examined racial (African American vs. white) and neighborhood poverty disparities in two emergency outcomes defined as: 1) newly diagnosed CRC or 2) CRC surgery associated with: obstruction, perforation, or emergency inpatient admission. Multilevel logistic regression (patients nested in census tracts) analyses adjusted for sociodemographic, tumor, and clinical covariates.ResultsOf 83,330 CRC patients, 29.1% were diagnosed emergently. Of 55,046 undergoing surgery, 26.0% had emergency surgery. For both outcomes, race and neighborhood poverty disparities were evident. A significant race by poverty interaction (p < .001) was noted: poverty rate was associated with both outcomes among African Americans, but not whites. Compared to whites in low poverty (<10%) neighborhoods, African Americans in high poverty (≥20%) neighborhoods had increased odds of emergency diagnosis (AOR: 1.50, 95% CI: 1.38-1.63) and surgery (AOR: 1.63, 95% CI: 1.47-1.81).ConclusionsEmergency CRC outcomes are associated with high poverty residence among African Americans in this population-based study, potentially contributing to observed disparities in CRC morbidity and mortality. Targeted efforts to increase CRC screening among African Americans living in high poverty neighborhoods could reduce preventable disparities

High-Capacity Communications from Martian Distances Part 4: Assessment of Spacecraft Pointing Accuracy Capabilities Required For Large Ka-Band Reflector Antennas

Improved surface accuracy for deployable reflectors has brought with it the possibility of Ka-band reflector antennas with extents on the order of 1000 wavelengths. Such antennas are being considered for high-rate data delivery from planetary distances. To maintain losses at reasonable levels requires a sufficiently capable Attitude Determination and Control System (ADCS) onboard the spacecraft. This paper provides an assessment of currently available ADCS strategies and performance levels. In addition to other issues, specific factors considered include: (1) use of "beaconless" or open loop tracking versus use of a beacon on the Earth side of the link, and (2) selection of fine pointing strategy (body-fixed/spacecraft pointing, reflector pointing or various forms of electronic beam steering). Capabilities of recent spacecraft are discussed