3,098 research outputs found
Causal Similarity-Based Hierarchical Bayesian Models
The key challenge underlying machine learning is generalisation to new data.
This work studies generalisation for datasets consisting of related tasks that
may differ in causal mechanisms. For example, observational medical data for
complex diseases suffers from heterogeneity in causal mechanisms of disease
across patients, creating challenges for machine learning algorithms that need
to generalise to new patients outside of the training dataset. Common
approaches for learning supervised models with heterogeneous datasets include
learning a global model for the entire dataset, learning local models for each
tasks' data, or utilising hierarchical, meta-learning and multi-task learning
approaches to learn how to generalise from data pooled across multiple tasks.
In this paper we propose causal similarity-based hierarchical Bayesian models
to improve generalisation to new tasks by learning how to pool data from
training tasks with similar causal mechanisms. We apply this general modelling
principle to Bayesian neural networks and compare a variety of methods for
estimating causal task similarity (for both known and unknown causal models).
We demonstrate the benefits of our approach and applicability to real world
problems through a range of experiments on simulated and real data
Long-lasting insecticide-treated net usage in eastern Sierra Leone - the success of free distribution.
Summary Objective Médecins Sans Frontières (MSF) runs a malaria control project in Bo and Pujehun districts (population 158 000) that includes the mass distribution, routine delivery and demonstration of correct use of free, long-lasting insecticide-treated nets (LLINs). In 2006/2007, around 65 000 LLINs were distributed. The aim of this follow-up study was to measure LLIN usage and ownership in the project area. Methods Heads of 900 randomly selected households in 30 clusters were interviewed, using a standardized questionnaire, about household use of LLINs. The condition of any LLIN was physically assessed. Results Of the 900 households reported, 83.4% owning at least one LLIN. Of the 16.6% without an LLIN, 91.9% had not participated in the MSF mass distribution. In 94.1% of the households reporting LLINs, the nets were observed hanging correctly over the beds. Of the 1135 hanging LLINs, 75.2% had no holes or 10 or fewer finger-size holes. The most common source of LLINs was MSF (75.2%). Of the 4997 household members, 67.2% reported sleeping under an LLIN the night before the study, including 76.8% of children under 5 years and 73.0% of pregnant women. Conclusion Our results show that MSF achieved good usage with freely distributed LLINs. It is one of the few areas where results almost achieve the new targets set in 2005 by Roll Back Malaria to have at least 80% of pregnant women and children under 5 years using LLINs by 2010
Biomaterials Redesign of Microvascular Anastomotic Coupler
The key factors in the redesign of this part include the use of biomaterials, the redesign of the part geometry to include these biomaterials, and the proposition of production scale manufacturing methods suitable for these redesigns. The choice of biodegradable material was guided by previous literature, during which we found the PLGA polymer used in similar predicate devices with a biodegradability timeline similar to our goals. The model of coupler serving as the inspiration for the redesign utilizes two very strong but bioinert materials, polyethylene, and stainless steel. These high strength materials can withstand much greater forces than the biodegradable bulk material chosen for the redesign, so features of the old design were modified for robustness. This included to realize this new design on a production scale, the two most promising possibilities include injection molding with the PLGA polymer or additive manufacturing using stereo lithography printers and biodegradable resins. The commonality of these two processes is the ability to make complex shapes while retaining isotropic materials in the final part, which is essential for the strength of small features such as the pins.
Key customer requirements for anastomotic procedures include successful attachments of vessels and low rates of dehiscence. These requirements are related to our coupler by successful attachment rate, max force withstood by coupler before assembly separates, max forces withstood by vessels before ripping.
Different models of the coupler device were tested in assembled orientation with one blood vessel surrogate engaged. In both models, tensions upwards of 100N were experienced without a signal failure of the pins. This demonstrates that the pins are exceptionally stronger when assembled into the opposite coupler than when unengaged.
Another factor in the improvement of the device is the time taken to film an implementation of the device using dissected cow arteries. The first round of prototypes required several people to affix the coupler and blood vessels and required additional processing of the cow arteries in the form of puncturing pilot holes for the spikes. Overall, the procedure took about an hour to perform. The latest model of prototypes was operated on in only a half hour and required only one person to perform the procedure. The improved placement and orientation of the spikes allow for much easier puncturing of the arterial wall for smoother attachments
Silicon carbide-based capillary membranes for gas separation and water treatment
Membrana cerámica no óxido a base de SiC se sintetizaron a partir de precursores disponibles comercialmente molecular y polvo de SiC. Cinco de Si / B / C polÃmeros precerámicos diferentes fueron sintetizados por reacción de hidroboración de precursor de carburo de silicio con borano. Análisis FTIR del polÃmero de Si / B / C sintetizado muestra que la intensidad del pico que indica la presencia de un doble enlace disminuye través de la reacción de hidroboración. En el segundo método, un soporte macroporoso capilar y carburo de silicio plana se sintetizaron a partir comercialmente disponible de SiC-SiC-500 y 800 junto con aditivos. Cinco composiciones diferentes se prepararon y la porosidad se controlan desde ~ 46-51% cambiando atmósfera de sinterización, la temperatura y la composición. Atmósfera de sinterización afecta a la porosidad y tamaño de poro más de la temperatura y agente formador de poros
Characterizing personalized effects of family information on disease risk using graph representation learning
Family history is considered a risk factor for many diseases because it
implicitly captures shared genetic, environmental and lifestyle factors. A
nationwide electronic health record (EHR) system spanning multiple generations
presents new opportunities for studying a connected network of medical
histories for entire families. In this work we present a graph-based deep
learning approach for learning explainable, supervised representations of how
each family member's longitudinal medical history influences a patient's
disease risk. We demonstrate that this approach is beneficial for predicting
10-year disease onset for 5 complex disease phenotypes, compared to
clinically-inspired and deep learning baselines for a nationwide EHR system
comprising 7 million individuals with up to third-degree relatives. Through the
use of graph explainability techniques, we illustrate that a graph-based
approach enables more personalized modeling of family information and disease
risk by identifying important relatives and features for prediction
Analysis of Circuits for Dosage Control in Microbial Populations
Designing genetic circuits to control the behaviors of microbial populations is an ongoing challenge in synthetic biology. Here we analyze circuits which implement dosage control by controlling levels of a global signal in a microbial population in face of varying cell density, growth rate, and environmental dilution. We utilize the Lux quorum sensing system to implement dosage control circuits, and we analyze the dynamics of circuits using both simplified analytical analysis and in silico simulations. We demonstrate that strong negative feedback through inhibiting LuxI synthase expression along with AiiA degradase activity results in circuits with fast response times and robustness to cell density and dilution rate. We find that degradase activity yields robustness to variations in population density for large population sizes, while negative feedback to synthase production decreases sensitivity to dilution rates
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Cultural value of architecture in homes and neighbourhoods
This paper provides an account of the Cultural Value of Architecture in Homes and Neighbourhoods, (CVoA), a project developed with the Royal Institute of British Architects (RIBA). The first stage of the project was a critical review of ‘grey literature’ since 2000, industry based research on the value of architecture subdivided into themes: overall value; health and wellbeing; neighbourhood cohesion and heritage and belonging. Findings from the review revealed a marked absence of evidence of the value of architecture and an over preoccupation with the final building, the product of an interdisciplinary team not just Architects, as well as a general confusion about what it is that Architects do. Further consultation has led to the development of a framework for defining and communicating the skillsets of Architects and for developing an evidence base for their value. Our target audience is non-Architects as we are concerned with making the profession more inclusive hence our desire to create simple definitions and terminology
DE LA CONSTITUTION D'UNE BASE DE DONNÉES DE RÉFÉRENCE SUR LA GÉOGRAPHIE DU COMMERCE
International audienc
Why Am I?: Farmington Honors Journal, Volume 4, Spring 2022
Hello again everyone,
Thank you for taking a second to look at our wonderful showcase of students artwork. One thing the two of us touched on during this editing process was the beauty in self reflection. Which is why we immediately knew that this collection of our fellow creative peers’ works repsresented an deep introspective exploration of self. And that deeply personal reflection is what we kept in mind as we continued to compile and think about these pieces. It is proven in the following pages that the work of a creative uncovering themselves is never done, and that there is so much more growth that comes from memory or heritage. We hope you enjoy these works as much as we have.
Sincerely,
BrookLyn Miller
Madisyn Smit
From national monitoring to transnational indicators: reporting and processing of aquatic biology data under the European Environment Agency’s State of the Environment data flow
Biological monitoring data from aquatic ecosystems are collected from European countries on a yearly basis by the European Environment Agency (EEA) through the Water Information System for Europe (WISE). The WISE-SoE (State of Environment) data flows provide indicators of pressures, states and impacts of surface waters and groundwaters on a pan-European scale. The WISE-2 Biology was established to obtain a harmonised flow of biology data reported annually as Ecological Quality Ratios (EQRs) from European surface waters, as a supplement to the mandatory 6-yearly reporting of ecological status of water bodies for the Water Framework Directive. The purposes of this paper are 1) to describe the compilation of national aquatic biology monitoring data indicators and to inform about the public availability of these data, 2) to give an overview of the reported data and indicate the potential for assessments based on these data, and 3) to illustrate the potential for further use of the underlying species abundance data in biodiversity research and assessment. WISE-2 data are reported for the following biological quality elements: phytoplankton, phytobenthos, macrophytes, macroalgae, angiosperms, benthic invertebrates and fish in rivers, lakes, transitional and/or coastal waters. The EQR values represent the deviation from reference conditions. The final processed and quality-checked data are published in EEA’s database Waterbase - Biology, which currently holds data from more than 13,000 waterbodies in 26 countries from the reporting years 2011–2021. Examples of time series aggregated by geographic regions give an indication of the type of trends that can be obtained from the reported data at the nEQR scale. However, the current results are representative only for certain geographic regions with high coverage of water bodies. Within the European research project EuropaBON (Europa Biodiversity Observation Network), the use of WISE-2 data can be leveraged to support biodiversity policy and conservation planning. EuropaBON’s online database provides an overview of how biodiversity monitoring schemes across Europe flows through different integration nodes, to produce Essential Biodiversity Variables and other policy-relevant indicators. Here, we use the EuropaBON visualisation tool to illustrate the WISE-2 as a European integration node for 157 biology datasets via the national integration nodes.publishedVersio
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