Stabilizing Building Foundations Threatened by the Pine Hills, Florida Sinkhole

On June 11, 2002, a 150-foot wide and 60-foot deep sinkhole collapsed in Pine Hills, near Orlando, Florida. The Pine Hills Sinkhole was the largest sinkhole to occur in Central Florida in the past 20 years. The collapse swallowed approximately 10,000 cubic yards of earth, sidewalks, light fixtures, a sanitary sewer and several large oak trees in less than 2 hours. The rim of the sinkhole came within a few feet of the shallow foundations of 2 three-story apartment buildings. Observation and subsequent geotechnical analysis showed that the sinkhole slope supporting the buildings was subject to imminent failure, and if a slope failure were to occur, it would likely result in a complete loss of the structures. The weather forecast predicted heavy rainfall, which could further destabilize the steep sand slope. Immediate action was taken to prevent slope failure, including the rerouting of stormwater roof drains and placement of a 30 mil-thick PVC liner over the slope adjacent to the buildings. A detailed geotechnical investigation including Ground Penetration Radar, electronic Cone Penetration Test soundings and Standard Penetration Test borings was immediately implemented to develop geotechnical parameters for remedial design. Due to critical time constraints, a chemical grouting program was conducted concurrently with the investigation to provide temporary stabilization of the building foundation soils from undermining due to the adjacent sinkhole. Settlement and cracking of the building slab foundations and walls were observed within a few days after the sinkhole collapsed, and the settlement and cracking accelerated with time. The permanent design solution for stabilizing the building foundations, and adjacent sidewalks and utilities, was installation of a Giken Wall using the Press-In installation method. The 200-foot long wall was located between the sinkhole and the buildings. The wall was comprised of 3-foot diameter interlocking steel pipe piles that were 50 feet in length. The combined internal auger and Press-In installation methodology allowed the wall to be constructed adjacent to the sensitive sand slope with negligible ground disturbance. The building movement was arrested by construction of the Giken wall and the building foundation stabilization was complete within 1 month after the sinkhole occurred. The relatively minor damage to the structures was then repaired and tenants have returned to occupy the buildings

Cargo adaptors regulate stepping and force generation of mammalian dynein-dynactin.

Cytoplasmic dynein is an ATP-driven motor that transports intracellular cargos along microtubules. Dynein adopts an inactive conformation when not attached to a cargo, and motility is activated when dynein assembles with dynactin and a cargo adaptor. It was unclear how active dynein-dynactin complexes step along microtubules and transport cargos under tension. Using single-molecule imaging, we showed that dynein-dynactin advances by taking 8 to 32-nm steps toward the microtubule minus end with frequent sideways and backward steps. Multiple dyneins collectively bear a large amount of tension because the backward stepping rate of dynein is insensitive to load. Recruitment of two dyneins to dynactin increases the force generation and the likelihood of winning against kinesin in a tug-of-war but does not directly affect velocity. Instead, velocity is determined by cargo adaptors and tail-tail interactions between two closely packed dyneins. Our results show that cargo adaptors modulate dynein motility and force generation for a wide range of cellular functions

Adolescent Mothers’ Implementation of Strategies to Enhance Their Children’s Early Language and Emergent Literacy Skills

Previous studies have examined how the language skills of children with adolescent mothers differs from children of older mothers. However, there is limited information on what specific strategies adolescent mothers utilize to increase early language and emergent literacy skills in their children. The aim of the present study is to examine adolescent mothers’ use of strategies to increase the early language and emergent literacy skills of their young children. A sample of 14 adolescent mothers enrolled in a teen parenting program were surveyed on their use of common strategies that are shown to facilitate early development of language and literacy skills in young children, and they provided a self-report of their child’s language development using a norm-referenced tool. A researcher developed questionnaire was used to determine the frequency of strategies used by the adolescent mothers. The MacArthur Bates Communicative Development Inventories were used to gather child language development data to compare with the frequency of strategy usage. The measures were analyzed with ANOVAs, Pearson Correlations and Spearman’s rank-order correlations to determine the significance and relationship between variables. Adolescent mothers were found to generally score low on the Self-Assessment of Language and Literacy Implementation (SALLI), with deficits specifically in the areas of Directiveness and Home Environment. The CDIs showed that the children were reported to have below average language development, and their scores were significantly related to aspects of the adolescent mother’s reported implementation

Chick tendon fibroblast transcriptome and shape depend on whether the cell has made its own collagen matrix

Collagen- and fibrin-based gels are extensively used to study cell behaviour. However, 2D-3D and collagen-fibrin comparisons of gene expression, cell shape and mechanotransduction, with an in vivo reference, have not been reported. Here we compared chick tendon fibroblasts (CTFs) at three stages of embryonic development with CTFs cultured in collagen- or fibrin-based tissue engineered constructs (TECs). CTFs synthesised their own collagen matrix in fibrin-based TECs and better recapitulated the gene expression, collagen fibril alignment and cell shape seen in vivo. In contrast, cells in 3D collagen gels exhibited a 2D-like morphology and expressed fewer of the genes expressed in vivo. Analysis of YAP/TAZ target genes showed that collagen gels desensitise mechanotransduction pathways. In conclusion, gene expression and cell shape are similar on plastic and 3D collagen whereas cells in 3D fibrin have a shape and transcriptome better resembling the in vivo situation. Implications for wound healing are discussed

VerdictDB: Universalizing Approximate Query Processing

Despite 25 years of research in academia, approximate query processing (AQP) has had little industrial adoption. One of the major causes of this slow adoption is the reluctance of traditional vendors to make radical changes to their legacy codebases, and the preoccupation of newer vendors (e.g., SQL-on-Hadoop products) with implementing standard features. Additionally, the few AQP engines that are available are each tied to a specific platform and require users to completely abandon their existing databases---an unrealistic expectation given the infancy of the AQP technology. Therefore, we argue that a universal solution is needed: a database-agnostic approximation engine that will widen the reach of this emerging technology across various platforms. Our proposal, called VerdictDB, uses a middleware architecture that requires no changes to the backend database, and thus, can work with all off-the-shelf engines. Operating at the driver-level, VerdictDB intercepts analytical queries issued to the database and rewrites them into another query that, if executed by any standard relational engine, will yield sufficient information for computing an approximate answer. VerdictDB uses the returned result set to compute an approximate answer and error estimates, which are then passed on to the user or application. However, lack of access to the query execution layer introduces significant challenges in terms of generality, correctness, and efficiency. This paper shows how VerdictDB overcomes these challenges and delivers up to 171$\times$ speedup (18.45$\times$ on average) for a variety of existing engines, such as Impala, Spark SQL, and Amazon Redshift, while incurring less than 2.6% relative error. VerdictDB is open-sourced under Apache License.Comment: Extended technical report of the paper that appeared in Proceedings of the 2018 International Conference on Management of Data, pp. 1461-1476. ACM, 201

Invasive earthworms erode soil biodiversity: A meta-analysis

Biological invasions pose a serious threat to biodiversity and ecosystem functioning across ecosystems. Invasions by ecosystem engineers, in particular, have been shown to have dramatic effects in recipient ecosystems. For instance, invasion by earthworms, a below-ground invertebrate ecosystem engineer, in previously earthworm-free ecosystems alters the physico-chemical characteristics of the soil. Studies have shown that such alterations in the soil can have far-reaching impacts on soil organisms, which form a major portion of terrestrial biodiversity. Here, we present the first quantitative synthesis of earthworm invasion effects on soil micro-organisms and soil invertebrates based on 430 observations from 30 independent studies. Our meta-analysis shows a significant decline of the diversity and density of soil invertebrates in response to earthworm invasion with anecic and endogeic earthworms causing the strongest effects. Earthworm invasion effects on soil micro-organisms were context-dependent, such as depending on functional group richness of invasive earthworms and soil depth. Microbial biomass and diversity increased in mineral soil layers, with a weak negative effect in organic soil layers, indicating that the mixing of soil layers by earthworms (bioturbation) may homogenize microbial communities across soil layers. Our meta-analysis provides a compelling evidence for negative effects of a common invasive below-ground ecosystem engineer on below-ground biodiversity of recipient ecosystems, which could potentially alter the ecosystem functions and services linked to soil biota.European Union's Horizon 2020, Grant/ Award Number: 677232; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; German Research Foundation, Grant/Award Number: FZT 11