35 research outputs found
South Skagit Highway realignment: ENVS 493 winter 2013
The existing placement of the South Skagit Highway disconnects the Skagit River from approximately 62 acres of floodplain in the project area alone and has direct impacts on habitat conditions. Approximately, 5.2 acres of wetlands are completely inaccessible to fish due to the current highway alignment. An additional 21.7 acres of slough and wetland habitat have only partial fish access due to restricted hydrologic connectivity with the river. Routine dredging and maintenance is required for the 900 feet of Savage Creek which currently runs in the highway ditch. Savage Slough runs under the highway through an undersized culvert that is often blocked by flooding from Mill Creek. An alluvial fan of Mill Creek runs under an undersized bridge making the channel prone to migration, avulsion, and erosion. The channel has been subject to numerous maintenance projects, including dredging and channelization. Seattle City Light (SCL) purchased approximately 212 acres of property on the Skagit River near Mill and Savage Creeks. A large portion of the acquired property has been deforested and disturbed by the South Skagit Highway, which runs through the Skagit River\u27s floodplain and disconnects a variety of existing tributary and wetland habitats. In order to implement habitat restoration and protect the property for conservation, SCL has been working with Skagit River System Cooperative (SRSC) and Skagit County to restore the floodplain to its original ecological functionality, providing habitat for several species. Maintenance costs of the current road would also be reduced. The restoration is likely to include demolition, riparian and floodplain plantings, and culvert removals. Possibilities for floodplain restoration were evaluated after an initial scoping procedure. Suggested restoration would either demolish and realign the existing road or install new bridges and culverts on the existing road. The initial scoping and evaluation narrowed the list of feasible projects down to two, mostly due to the Washington State Department of Transportation\u27s (WSDOT) high cost estimate of the other projects. Project funding has come from both SCL and the Salmon Recovery Funding Board (SRFB, project #091450) and several additional sources
Encapsulated nanowires : boosting electronic transport in carbon nanotubes
The electrical conductivity of metallic carbon nanotubes (CNTs) quickly saturates with respect to bias voltage due to scattering from a large population of optical phonons. The decay of these dominant scatterers in pristine CNTs is too slow to offset an increased generation rate at high voltage bias. We demonstrate from first principles that encapsulation of one-dimensional atomic chains within a single-walled CNT can enhance the decay of âhotâ phonons by providing additional channels for thermalization. Pacification of the phonon population growth reduces the electrical resistivity of metallic CNTs by 51% for an example system with encapsulated beryllium
Scene coordinate reconstruction: posing of image collections via incremental learning of a relocalizer
We address the task of estimating camera parameters from a set of images depicting a scene. Popular feature-based structure-from-motion (SfM) tools solve this task by incremental reconstruction: they repeat triangulation of sparse 3D points and registration of more camera views to the sparse point cloud. We re-interpret incremental structure-from-motion as an iterated application and refinement of a visual relocalizer, that is, of a method that registers new views to the current state of the reconstruction. This perspective allows us to investigate alternative visual relocalizers that are not rooted in local feature matching. We show that scene coordinate regression, a learning-based relocalization approach, allows us to build implicit, neural scene representations from unposed images. Different from other learning-based reconstruction methods, we do not require pose priors nor sequential inputs, and we optimize efficiently over thousands of images. Our method, ACE0 (ACE Zero), estimates camera poses to an accuracy comparable to feature-based SfM, as demonstrated by novel view synthesis. Project page: https://nianticlabs.github.io/acezero
Outcomes of interventions in neonatal sepsis:A systematic review of qualitative research
BackgroundWhile a systematic review exists detailing neonatal sepsis outcomes from clinical trials, there remains an absence of a qualitative systematic review capturing the perspectives of key stakeholders.ObjectivesOur aim is to identify outcomes from qualitative research on any intervention to prevent or improve the outcomes of neonatal sepsis that are important to parents, other family members, healthcare providers, policymakers, and researchers as a part of the development of a core outcome set (COS) for neonatal sepsis.Search StrategyA literature search was carried out using MEDLINE, EMBASE, CINAHL, and PsycInfo databases.Selection CriteriaPublications describing qualitative data relating to neonatal sepsis outcomes were included.Data Collection and AnalysisDrawing on the concepts of thematic synthesis, texts related to outcomes were coded and grouped. These outcomes were then mapped to the domain headings of an existing model.Main ResultsOut of 6777 records screened, six studies were included. Overall, 19 outcomes were extracted from the included studies. The most frequently reported outcomes were those in the domains related to parents, healthcare workers and individual organ systemas such as gastrointestinal system. The remaining outcomes were classified under the headings of general outcomes, miscellaneous outcomes, survival, and infection.ConclusionsThe outcomes identified in this review are different from those reported in neonatal sepsis clinical trials, thus highlighting the importance of incorporating qualitative studies into COS development to encapsulate all relevant stakeholders' perspectives.This study reviews outcomes considered important in neonatal sepsis by stakeholders such as parents and healthcare providers, aiding in developing a core outcome set (COS)
Heart Matters: a study protocol for a community based randomized trial aimed at reducing cardiovascular risk in a rural, African American community
Abstract
Background
African Americans living in the rural south have the highest prevalence of cardiovascular disease (CVD) risk in the United States. Given this geographic and racial disparity, intervention implementation needs to be evaluated for effectiveness and feasibility with African Americans in the rural south.
Methods
The trial developed out of a community-based participatory research partnership, Project GRACE, and community partners who are collaborators throughout the study. Heart Matters is a randomized stepped wedge trial that will assess the effectiveness of a 12-month behavioral change intervention adapted from PREMIER, an evidence-based treatment targeting multiple CVD risk factors. 140 participants will be recruited through 8 community- or faith-based organizations to participate in the intervention. Through matched pair randomization, organizations will be randomized to begin immediately after baseline data collection (Arm 1) or delayed 6Â months (Arm 2). Data collection will occur at baseline, 6, 12, and 18Â months. The primary outcome is change in body weight. In addition to assessing effectiveness, the study will also evaluate process and feasibility outcomes through quantitative and qualitative data collection.
Discussion
This study will contribute to CVD prevention research and likely have a positive impact on the rural, African American community where the trial occurs. Our study is unique in its use of community partnerships to develop, implement, and evaluate the intervention. We expect that this approach will enhance the feasibility of the trial, as well as future dissemination and sustainability of the intervention.
Trial registration
Clinical Trials,
NCT02707432
. Registered 13 March 2016
Incidence and phenotypes of childhood-onset genetic epilepsies:a prospective population-based national cohort
Epilepsy is common in early childhood. In this age group it is associated with high rates of therapy-resistance, and with cognitive, motor, and behavioural comorbidity. A large number of genes, with wide ranging functions, are implicated in its aetiology, especially in those with therapy-resistant seizures. Identifying the more common single-gene epilepsies will aid in targeting resources, the prioritization of diagnostic testing and development of precision therapy. Previous studies of genetic testing in epilepsy have not been prospective and population-based. Therefore, the population-incidence of common genetic epilepsies remains unknown. The objective of this study was to describe the incidence and phenotypic spectrum of the most common single-gene epilepsies in young children, and to calculate what proportion are amenable to precision therapy. This was a prospective national epidemiological cohort study. All children presenting with epilepsy before 36 months of age were eligible. Children presenting with recurrent prolonged (>10 min) febrile seizures; febrile or afebrile status epilepticus (>30 min); or with clusters of two or more febrile or afebrile seizures within a 24-h period were also eligible. Participants were recruited from all 20 regional paediatric departments and four tertiary childrenâs hospitals in Scotland over a 3-year period. DNA samples were tested on a custom-designed 104-gene epilepsy panel. Detailed clinical information was systematically gathered at initial presentation and during follow-up. Clinical and genetic data were reviewed by a multidisciplinary team of clinicians and genetic scientists. The pathogenic significance of the genetic variants was assessed in accordance with the guidelines of UK Association of Clinical Genetic Science (ACGS). Of the 343 patients who met inclusion criteria, 333 completed genetic testing, and 80/333 (24%) had a diagnostic genetic finding. The overall estimated annual incidence of single-gene epilepsies in this well-defined population was 1 per 2120 live births (47.2/100 000; 95% confidence interval 36.9â57.5). PRRT2 was the most common single-gene epilepsy with an incidence of 1 per 9970 live births (10.0/100 000; 95% confidence interval 5.26â14.8) followed by SCN1A: 1 per 12 200 (8.26/100 000; 95% confidence interval 3.93â12.6); KCNQ2: 1 per 17 000 (5.89/100 000; 95% confidence interval 2.24â9.56) and SLC2A1: 1 per 24 300 (4.13/100 000; 95% confidence interval 1.07â7.19). Presentation before the age of 6 months, and presentation with afebrile focal seizures were significantly associated with genetic diagnosis. Single-gene disorders accounted for a quarter of the seizure disorders in this cohort. Genetic testing is recommended to identify children who may benefit from precision treatment and should be mainstream practice in early childhood onset epilepsy
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First-principles structure prediction of extreme nanowires
Low-dimensional systems are an important and intensely studied area of condensed matter physics. When a material is forced to adopt a low-dimensional structure, its behaviour is often dramatically different to that of the bulk phase. It is vital to predict the structures of low-dimensional systems in order to reliably predict their properties. To this end, the ab initio random structure searching (AIRSS) method, which has previously been used to identify the structures of bulk materials, has been extended to deal with the case of nanowires encapsulated inside carbon nanotubes. Such systems are a rapidly developing area of research with important nanotechnological applications, including information storage, energy storage and chemical sensing.
The extended AIRSS method for encapsulated nanowires (ENWs) was implemented and used to identify the structures formed by germanium telluride, silver chloride, and molybdenum diselenide ENWs. In each of these cases, a number of novel nanowire structures were identified, and a phase diagram predicting the ground state nanowire structure as a function of the radius of the encapsulating nanotube was calculated. In the case of germanium telluride, which is a technologically important phase-change material, the potential use of GeTe ENWs as switchable nanoscale memory devices was investigated.
The vibrational properties of silver chloride ENWs were also considered, and a novel scheme was developed to predict the Raman spectra of systems which can be decomposed into multiple weakly interacting subsystems. This scheme was used to obtain a close approximation to the Raman spectra of AgCl ENWs at a fraction of the computational cost that would otherwise be necessary. The encapsulation of AgCl was shown to produce substantial shifts in the Raman spectra of nanotubes, providing an important link with experiment.
A method was developed to predict the stress-strain response of an ENW based on a polygonal representation of its surface, and was used to investigate the elastic response of molybdenum diselenide ENWs. This was used to predict stress-radius phase diagrams for MoSe ENWs, and hence to investigate stress-induced phase change within such systems.
The X-ray diffraction of ENWs was also considered. A program was written to simulate X-ray diffraction in low-dimensional systems, and was used to predict the diffraction patterns of some of the encapsulated GeTe nanowire structures predicted by AIRSS. By modelling the interactions within a bundle of nanotubes, diffraction patterns for bundles of ENWs were obtained
Data for Electronic structure control of sub-nanometer 1D SnTe via nanostructuring within single-walled carbon nanotubes
Nanostructuring, e.g. reduction of dimensionality in materials offers a viable route towards regulation of materials electronic and hence functional properties. Here, we present the extreme case of nanostructuring, exploiting capillarity of single-walled carbon nanotubes (SWCNTs) for synthesis of the smallest possible SnTe nanowires with cross sections as small as a single atom column. We demonstrate that by choosing the appropriate diameter of a template SWCNT, we can manipulate the structure of the quasi-one-dimensional (1D) SnTe and to design electronic behaviour. From first principles, we predict structural reformations SnTe undergoes in varying encapsulation and confront the prediction with TEM imagery. To further illustrate the control of physical properties by nanostructuring we study the evolution of transport properties in a homologous series of models of synthesised and isolated SnTe nanowires varying only by morphology and atomic layer thickness. This extreme scaling is predicted to significantly enhance thermoelectric performance of SnTe, offering a prospect for further experimental studies and future applications