What Syntactic Structures block Dependencies in RNN Language Models?

Recurrent Neural Networks (RNNs) trained on a language modeling task have been shown to acquire a number of non-local grammatical dependencies with some success. Here, we provide new evidence that RNN language models are sensitive to hierarchical syntactic structure by investigating the filler--gap dependency and constraints on it, known as syntactic islands. Previous work is inconclusive about whether RNNs learn to attenuate their expectations for gaps in island constructions in particular or in any sufficiently complex syntactic environment. This paper gives new evidence for the former by providing control studies that have been lacking so far. We demonstrate that two state-of-the-art RNN models are are able to maintain the filler--gap dependency through unbounded sentential embeddings and are also sensitive to the hierarchical relationship between the filler and the gap. Next, we demonstrate that the models are able to maintain possessive pronoun gender expectations through island constructions---this control case rules out the possibility that island constructions block all information flow in these networks. We also evaluate three untested islands constraints: coordination islands, left branch islands, and sentential subject islands. Models are able to learn left branch islands and learn coordination islands gradiently, but fail to learn sentential subject islands. Through these controls and new tests, we provide evidence that model behavior is due to finer-grained expectations than gross syntactic complexity, but also that the models are conspicuously un-humanlike in some of their performance characteristics.Comment: To Appear at the 41st Annual Meeting of the Cognitive Science Society, Montreal, Canada, July 201

The development and implementation of a hip injury screening protocol within elite ice hockey

The primary aim of this project was to both investigate injury epidemiology and create methods to potentially reduce injuries within elite ice hockey athletes. Chapter Four assessed the injury problem within ice hockey by retrospectively collecting data from two National Collegiate Athletic Association (NCAA) division III teams across a four year period investigating the prevalence, location, severity and type of injuries sustained. Findings showed that contact injuries were more prevalent (58%) than non-contact injuries (42%), with the knee (15%), shoulder (12%) and hip (13%) being the most frequently injured locations when both contact and non-contact injuries were combined. When investigating only non- contact injuries the hip complex (hip, groin and thigh) (50%) was by far the most injured location with similar frequencies, in terms of injury severity, observed.Chapter Five analysed intrinsic risk factors of the ice hockey athlete by investigating differences of hip range of motion (ROM), strength and functional tests between ice hockey athletes, soccer athletes and control participants. Results demonstrated that ice hockey athletes had significantly weaker hip adduction (p = 0.023) and flexion in sitting (p = 0.001) strength compared to soccer athletes and less external rotation strength compared to control participants (p = 0.010). Ice hockey athletes also displayed greater strength than control participants in flexion in sitting (p = 0.005). Ice hockey athletes exhibited greater ROM in abduction (p = 0.001) than control participants and greater adduction than both soccer athletes (p = 0.003) and control participants (p = 0.004). Ice hockey athletes exhibited less hip flexion in lying (p = 0.001) and external rotation (p < 0.001) when compared to control participants. Ice hockey athletes also presented with an increased number of positive flexion, abduction and external rotation (FABER) tests compared to both soccer athletes and control participants.Chapter Six investigated the effectiveness of the newly created hip screen by comparing ice hockey athletes with and without a previous non-contact hip injury and their performance during the hip screen. Findings demonstrated that athletes who had no previous hip injury had greater internal (p = 0.004) and external rotation ROM (p = 0.022) on the dominant (Dom) limb and greater flexion in sitting (p = 0.031) and internal rotation ROM (p = 0.050) on the non-dominant (Ndom) limb. Although non-significant, previously injured athletes also displayed less ROM in all hip movements compared to previously uninjured athletes. Similar trends were found in strength measures with previously uninjured athletes showing significantly stronger abduction (p = 0.012) on the Dom limb and flexion in lying on both the Dom (p = 0.008) and Ndom limb (p < 0.001). Previously injured athletes displayed more positive FABER (Dom; 13% vs. 0%, Ndom; 13% vs. 5%), Trendelenburg (Dom; 75% vs. 58%, Ndom; 50% vs. 5%) and Ober’s (Dom; 13% vs. 5%, Ndom; 75% vs. 68%) tests with higher scores on the overall screen than uninjured athletes.Chapter Seven investigated the intra and inter-tester reliability of the hip screen finding that intra-class correlation coefficients (ICC) of intra-tester reliability of the ROM (0.49), strength (0.80) and overall screen (0.76) was moderate to near perfect. Inter-tester reliability again showed very large ICCs for ROM (0.71), strength (0.77) and overall screen scores (0.81). The minimum criterion change (MCC) (3.78 points) was also found to be small for the screen score change needed to be viewed as clinically worthwhile. These findings demonstrate that the screening procedure developed is useful, reliable and repeatable when assessing the ice hockey athlete’s hip.Chapter Eight demonstrated that all participants regardless of group improved their ROM and strength measures following the intervention period. However, it was demonstrated that the ice hockey intervention (IHI) group saw a decrease in the amount of positive FABER tests following the intervention compared to ice hockey control (IHC) and intervention control (IC) group (IHI: pre 15 vs. post 6; IHC: pre 15 vs. post 14; IC: pre 10 vs. post 9). It was also demonstrated that the IHI group improved above the MCC value presented within Chapter Seven with regards to the overall hip injury screen score (pre 48 vs. post 52) indicating that ice hockey athletes who participated in the intervention programme may be at a decreased risk of sustaining a non-contact hip injury due to the intervention exercises targeting weaknesses highlighted in the hip injury screen.In summary, the current project achieved the stated aims by demonstrating that the hip complex was the most common location for injuries of a non-contact nature and the creation of a reliable and repeatable hip injury screen that allows clinicians to potentially highlight athletes considered as ‘at risk’. To complete the injury prevention sequence, future work would be necessary to track athletes who scored low on the hip injury screen over time either following the intervention or as a control to assess if they were more or less likely to sustain a non-contact hip injury. Future work should also continue to optimise the intervention strategy to further develop and enhance its effectiveness in the prevention of non-contact hip injuries. This could be achieved either through a longer protocol that is incorporated into routine training or individualisation of the programme and as such provide a valuable tool for clinicians and medical teams wishing to reduce the risk of ice hockey athletes sustaining a non-contact hip injury

New Records for Sphagnum in Indiana

The Indiana Sphagnum flora is expanded from 10 to 28 species. Sphagnum.henryense, S. recurvum, and S. bartlettianum are more southerly species reaching northern limits while S.centrale, S. papillosum, S. squarrosum, S. teres, S. contortum, S. platyphyllum, S. fallax, S.flexuosum, S. augustifolium, S. pulchrum, S. riparium, S. capillifolium, S. subtile, S. rubellum, S.fuscum, S. girgensohnii, S. russowii, S. fimbriatum, and S. wulfianum are northern species which reach a southern limit in Indiana. One half of the northern species are limited to the three northern counties bordering Lake Michigan, but the occurrence of the other half in an apparently recently colonized abandoned sandstone quarry in the middle of the state suggests that the limiting factor may be habitat more than climate. The most extensive peatland in the state, Pinhook Bog, is briefly characterized

The Role of Sphagnum Fimbriatum in Secondary Succession in a Road-Salt Impacted Bog

Secondary succession of Sphagnum mosses was studied for 7 years along a belt transect in a bog that had been impacted by sodium chloride highway deicing salts. Laboratory studies on Sphagnumfimbriatum Wils., the dominant recolonizing species, were conducted to determine its salt tolerance level and ability to reproduce from spores and fragments across a salt gradient. Vegetative reproduction was also compared with that of four other recolonizing species. Sphagnumfimbriatum represented a high percentage of all recolonizing Sphagnum and generally began growing on low hummocks in quadrats where the salt content of the interstitial peat pore waters had dropped to about 300 mg/L as chloride. This salt concentration was also found to be the basic tolerance limit for mature plants and reproducing spores and fragments. The success of Sphagnum fimbriatum as a pioneer species seems to be associated with its prolific production and probable dispersal of spores, its superior vegetative reproduction, its tolerance of mineralized waters, and its ability to grow on hummocks out of direct contact with mineralized waters

Dynamic reusable workflows for ocean science

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Marine Science and Engineering 4 (2016): 68, doi:10.3390/jmse4040068.Digital catalogs of ocean data have been available for decades, but advances in standardized services and software for catalog searches and data access now make it possible to create catalog-driven workflows that automate—end-to-end—data search, analysis, and visualization of data from multiple distributed sources. Further, these workflows may be shared, reused, and adapted with ease. Here we describe a workflow developed within the US Integrated Ocean Observing System (IOOS) which automates the skill assessment of water temperature forecasts from multiple ocean forecast models, allowing improved forecast products to be delivered for an open water swim event. A series of Jupyter Notebooks are used to capture and document the end-to-end workflow using a collection of Python tools that facilitate working with standardized catalog and data services. The workflow first searches a catalog of metadata using the Open Geospatial Consortium (OGC) Catalog Service for the Web (CSW), then accesses data service endpoints found in the metadata records using the OGC Sensor Observation Service (SOS) for in situ sensor data and OPeNDAP services for remotely-sensed and model data. Skill metrics are computed and time series comparisons of forecast model and observed data are displayed interactively, leveraging the capabilities of modern web browsers. The resulting workflow not only solves a challenging specific problem, but highlights the benefits of dynamic, reusable workflows in general. These workflows adapt as new data enter the data system, facilitate reproducible science, provide templates from which new scientific workflows can be developed, and encourage data providers to use standardized services. As applied to the ocean swim event, the workflow exposed problems with two of the ocean forecast products which led to improved regional forecasts once errors were corrected. While the example is specific, the approach is general, and we hope to see increased use of dynamic notebooks across geoscience domains

At what sample size do correlations stabilize?

Sample correlations converge to the population value with increasing sample size, but the estimates are often inaccurate in small samples. In this report we use Monte-Carlo simulations to determine the critical sample size from which on the magnitude of a correlation can be expected to be stable. The necessary sample size to achieve stable estimates for correlations depends on the effect size, the width of the corridor of stability (i.e., a corridor around the true value where deviations are tolerated), and the requested confidence that the trajectory does not leave this corridor any more. Results indicate that in typical scenarios the sample size should approach 250 for stable estimates

A Paleoecological Test of a Classical Hydrosere in the Lake Michigan Dunes

Aquatic vegetation varies along a chronosequence of dune ponds at Miller Woods, Indiana Dunes National Lakeshore. Submersed and floating-leaved macrophytes dominate the vegetation of the youngest ponds. Older ponds contain mixed assemblages of submersed, floating-leaved, and emergent plant taxa. The oldest ponds are dominated by emergent plants, especially Typha angustifolia. We conducted paleoecological studies at one of the oldest ponds to test the hypothesis that the modern vegetational array along the pond chronosequence represents a hydrarch successional sequence. Macrofossil stratigraphy of the 3000-yr-old pond indicates no significant changes in pond vegetation following early colonization until \u3c 150 BP. Pond vegetation before 150 BP consisted of a diverse assemblage of submersed, floating-leaved, and emergent macrophyte taxa. Pollen and macrofossil data indicate a major, rapid vegetational change at \u3c150 BP, evidently in response to local human disturbance. Pollen data reveal that the extensive Typha stands in the older ponds have developed recently, following postsettlement disturbance. Modern vegetational differences along the chronosequence reflect differential effects of disturbance rather than autogenic hydrarch succession. This study illustrates a major pitfall in inferring successional trends from spatial sequences of vegetation