74 research outputs found
Deep learning for the rapid automatic quantification and characterization of rotator cuff muscle degeneration from shoulder CT datasets.
This study aimed at developing a convolutional neural network (CNN) able to automatically quantify and characterize the level of degeneration of rotator cuff (RC) muscles from shoulder CT images including muscle atrophy and fatty infiltration.
One hundred three shoulder CT scans from 95 patients with primary glenohumeral osteoarthritis undergoing anatomical total shoulder arthroplasty were retrospectively retrieved. Three independent radiologists manually segmented the premorbid boundaries of all four RC muscles on standardized sagittal-oblique CT sections. This premorbid muscle segmentation was further automatically predicted using a CNN. Automatically predicted premorbid segmentations were then used to quantify the ratio of muscle atrophy, fatty infiltration, secondary bone formation, and overall muscle degeneration. These muscle parameters were compared with measures obtained manually by human raters.
Average Dice similarity coefficients for muscle segmentations obtained automatically with the CNN (88% ± 9%) and manually by human raters (89% ± 6%) were comparable. No significant differences were observed for the subscapularis, supraspinatus, and teres minor muscles (p > 0.120), whereas Dice coefficients of the automatic segmentation were significantly higher for the infraspinatus (p < 0.012). The automatic approach was able to provide good-very good estimates of muscle atrophy (R <sup>2</sup> = 0.87), fatty infiltration (R <sup>2</sup> = 0.91), and overall muscle degeneration (R <sup>2</sup> = 0.91). However, CNN-derived segmentations showed a higher variability in quantifying secondary bone formation (R <sup>2</sup> = 0.61) than human raters (R <sup>2</sup> = 0.87).
Deep learning provides a rapid and reliable automatic quantification of RC muscle atrophy, fatty infiltration, and overall muscle degeneration directly from preoperative shoulder CT scans of osteoarthritic patients, with an accuracy comparable with that of human raters.
• Deep learning can not only segment RC muscles currently available in CT images but also learn their pre-existing locations and shapes from invariant anatomical structures visible on CT sections. • Our automatic method is able to provide a rapid and reliable quantification of RC muscle atrophy and fatty infiltration from conventional shoulder CT scans. • The accuracy of our automatic quantitative technique is comparable with that of human raters
An automated microreactor for semi-continuous biosensor measurements.
Living bacteria or yeast cells are frequently used as bioreporters for the detection of specific chemical analytes or conditions of sample toxicity. In particular, bacteria or yeast equipped with synthetic gene circuitry that allows the production of a reliable non-cognate signal (e.g., fluorescent protein or bioluminescence) in response to a defined target make robust and flexible analytical platforms. We report here how bacterial cells expressing a fluorescence reporter ("bactosensors"), which are mostly used for batch sample analysis, can be deployed for automated semi-continuous target analysis in a single concise biochip. Escherichia coli-based bactosensor cells were continuously grown in a 13 or 50 nanoliter-volume reactor on a two-layered polydimethylsiloxane-on-glass microfluidic chip. Physiologically active cells were directed from the nl-reactor to a dedicated sample exposure area, where they were concentrated and reacted in 40 minutes with the target chemical by localized emission of the fluorescent reporter signal. We demonstrate the functioning of the bactosensor-chip by the automated detection of 50 μgarsenite-As l(-1) in water on consecutive days and after a one-week constant operation. Best induction of the bactosensors of 6-9-fold to 50 μg l(-1) was found at an apparent dilution rate of 0.12 h(-1) in the 50 nl microreactor. The bactosensor chip principle could be widely applicable to construct automated monitoring devices for a variety of targets in different environments
Sediment redistribution beneath the terminus of an advancing glacier, Taku Glacier (T’aakú Kwáan Sít’i), Alaska.
The recently-advancing Taku Glacier is excavating subglacial sediments at high rates over multidecadal timescales. However, sediment redistribution over shorter timescales remains unquantified. We use a variety of methods to study subglacial and proglacial sediment redistribution on decadal, seasonal, and daily timescales to gain insight into sub- and proglacial landscape formation. Both excavation and deposition were observed from 2003 to 2015 (2.8 ± 0.9ma−1 to +2.9 ± 0.9ma−1). The observed patterns imply that a subglacial conduit has occupied the same site over the past decade. Outwash fans on the subaerial end moraine experience fluvial sediment reworking almost year-round, with net sediment gain in winter and net sediment loss in summer, and an overall mass gain between 2005 and 2015.We estimate that tens of meters of sediment still underlie the glacier terminus, sediments which can be remobilized during future activity. However, imminent retreat from the proglacial moraine will limit its sediment supply, leaving the moraine vulnerable to erosion by bordering rivers. Retreat into an over-deepened basin will leave the glacier vulnerable to increased frontal ablation and accelerating retreat.Ye
Buildings behaving badly:A behavioral experiment on how different motivational frames influence residential energy label adoption in the Netherlands
Heating buildings contributes to approximately 36% of Europe’s energy demand and several EU member states have adopted mandatory energy labels to improve energy efficiency by promoting home weatherization investments. This paper focuses on the perception of the energy label for residential buildings in the Netherlands and the role of different frames (egoistic, biospheric and social norms and neutral frames) in motivating adoption of energy labels for housing. We used a behavioral email experiment and an online survey to investigate these motivational factors. We find that biospheric frames are weaker than the other three motivational frames in terms of engaging interest in the energy label, but that the biospheric frame results in higher willingness to pay (WTP) for the energy label. We also find that age (rather than income) correlates with higher willingness to pay for home energy labels
Observing calving-generated ocean waves with coastal broadband seismometers, Jakobshavn Isbræ, Greenland
We use time-lapse photography, MODIS satellite imagery, ocean wave measurements and
regional broadband seismic data to demonstrate that icebergs that calve from Jakobshavn Isbræ,
Greenland, can generate ocean waves that are detectable over 150 km from their source.We use time-lapse photography, MODIS satellite imagery, ocean wave measurements and
regional broadband seismic data to demonstrate that icebergs that calve from Jakobshavn Isbræ,
Greenland, can generate ocean waves that are detectable over 150 km from their source. The waves,
which are recorded seismically, have distinct spectral peaks, are not dispersive and persist for several
hours. On the basis of these observations, we suggest that calving events at Jakobshavn Isbræ can
stimulate seiches, or basin eigenmodes, in both Ilulissat Icefjord and Disko Bay. Our observations
furthermore indicate that coastal, land-based seismometers located near calving termini (e.g. as part
of the new Greenland Ice Sheet Monitoring Network (GLISN)) can aid investigations into the largely
unexplored, oceanographic consequences of iceberg calving.Funding for this project was provided by NASA’s Cryospheric
Sciences Program (NNG06GB49G), the US National
Science Foundation (ARC0531075, ARC0909552 and
ANT0944193), the Swiss National Science Foundation
(200021-113503/1) and a Cooperative Institute for Arctic
Research (CIFAR) International Polar Year (IPY) student
fellowship under US National Oceanic and Atmospheric
Administration (NOAA) cooperative agreement NA17RJ1224
with the University of Alaska. The seismic data were col-
lected and distributed by the Greenland Ice Sheet Monitoring
Network (GLISN) federation and its members: data from
GDH were collected by the Geological Survey of Denmark
and Greenland (GEUS); data from ASI, ILU and SUMG were
collected by GEOFON; data from SFJ/SFJD were collected
by GEUS, GEOFON, Incorporated Research Institutions for
Seismology (IRIS) and the Comprehensive Test-Ban Treaty
Organization (CTBTO); and data from ILULI were collected
by ETH. We thank J. Brown and D. Podrasky for assistance
with fieldwork and D.R. MacAyeal and E.A. Okal for
discussions that led to and improved the manuscript. The
manuscript benefited from the comments of O. Sergienko,
an anonymous reviewer and editor P. Christoffersen.Ye
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One transition, many transitions? A corpus-based study of societal sustainability transition discourses in four civil society’s proposals
When the civil society makes ‘transition’ its label, it cannot be assumed that different civil society actors share compatible varieties of localist or radical transformationists discourses. This study has comparatively analyzed the discourses in four civil society sustainability transition proposals using a corpus-based methodology. We found that the proposals are similar as they identify the economy as an object and an entry point for transition, frame the economy as embedded in the socio–ecological system, ascribe agency to grassroots movements for transitions from the bottom–up. We also found crucial differences among the discourses regarding the role of the State, the degree of reform or radical innovation, the degree of imaginative character of the sustainability vision, the degree of opposition to capitalism. We suggest that insights on how the civil society employs notions of transition with respect to the themes of politics, emotions and place can help advance theorizations and practices of societal sustainability transitions led by the civil society
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Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
The Thwaites Eastern Ice Shelf (TEIS) buttresses the eastern grounded portion of Thwaites Glacier through contact with a pinning point at its seaward limit. Loss of this ice shelf will promote further acceleration of Thwaites Glacier. Understanding the dynamic controls and structural integrity of the TEIS is therefore important to estimating Thwaites' future sea-level contribution. We present a ∼ 20-year record of change on the TEIS that reveals the dynamic controls governing the ice shelf's past behaviour and ongoing evolution. We derived ice velocities from MODIS and Sentinel-1 image data using feature tracking and speckle tracking, respectively, and we combined these records with ITS_LIVE and GOLIVE velocity products from Landsat-7 and Landsat-8. In addition, we estimated surface lowering and basal melt rates using the Reference Elevation Model of Antarctica (REMA) DEM in comparison to ICESat and ICESat-2 altimetry. Early in the record, TEIS flow dynamics were strongly controlled by the neighbouring Thwaites Western Ice Tongue (TWIT). Flow patterns on the TEIS changed following the disintegration of the TWIT around 2008, with a new divergence in ice flow developing around the pinning point at its seaward limit. Simultaneously, the TEIS developed new rifting that extends from the shear zone upstream of the ice rise and increased strain concentration within this shear zone. As these horizontal changes occurred, sustained thinning driven by basal melt reduced ice thickness, particularly near the grounding line and in the shear zone area upstream of the pinning point. This evidence of weakening at a rapid pace suggests that the TEIS is likely to fully destabilize in the next few decades, leading to further acceleration of Thwaites Glacier.
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‘Demand pull’ government policies to support Product-Service System activity: the case of Energy Service Companies (ESCos) in the UK
Product-Service Systems (PSSs) constitute a family of service-based business models designed to satisfy
our societal needs in an economically and environmentally sustainable manner. To date however PSS
application has remained niche due to a variety of critical barriers. This paper explores how ‘demand
pull’ national government policies could support PSS activity by addressing these barriers and cultivating
market demand. Lessons are drawn from a case study of how regulatory, economic incentive, informative
and procurement policies have supported Energy Service Company (ESCo) activity in the UK; a sub-set of
the PSS family focused on energy service provision. Subsequently five policy recommendations are
presented to support PSS activity: (1) balancing economic incentives and regulatory disincentives; (2)
promoting indirect policy support; (3) redesigning existing market structures; (4) promoting locally-led
PSS activity; and (5) creating stable policy frameworks. The paper warns however that national government
policy cannot easily address all PSS barriers, such as customer preferences, international developments,
technological progress and inherent business model weaknesses, pointing to the need for
other complementary solutions. Furthermore, other governance actors beside national government could
also implement PSS supporting policies
Sub-ice-shelf sediments record history of twentieth-century retreat of Pine Island Glacier
The article of record as published may be found at http://dx.doi.org/10.1038/nature20136The West Antarctic Ice Sheet is one of the largest potential sources of rising sea levels. Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line—which marks the boundary between grounded ice and floating ice shelf—is underway. Understanding this recent retreat requires a detailed knowledge of grounding-line history, but the locations of the grounding line before the advent of satellite monitoring in the 1990s are poorly dated. In particular, a history of grounding-line retreat is required to understand the relative roles of contemporaneous ocean-forced change and of ongoing glacier response to an earlier perturbation in driving ice-sheet loss. Here we show that the present thinning and retreat of Pine Island Glacier in West Antarctica is part of a climatically forced trend that was triggered in the 1940s. Our conclusions arise from analysis of sediment cores recovered beneath the floating Pine Island Glacier ice shelf, and constrain the date at which the grounding line retreated from a prominent seafloor ridge. We find that incursion of marine water beyond the crest of this ridge, forming an ocean cavity beneath the ice shelf, occurred in 1945 (±12 years); final ungrounding of the ice shelf from the ridge occurred in 1970 (±4 years). The initial opening of this ocean cavity followed a period of strong warming of West Antarctica, associated with El Niño activity. Furthermore our results suggest that, even when climate forcing weakened, ice-sheet retreat continued.USDO
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