432 research outputs found
Model Agnostic Saliency for Weakly Supervised Lesion Detection from Breast DCE-MRI
There is a heated debate on how to interpret the decisions provided by deep
learning models (DLM), where the main approaches rely on the visualization of
salient regions to interpret the DLM classification process. However, these
approaches generally fail to satisfy three conditions for the problem of lesion
detection from medical images: 1) for images with lesions, all salient regions
should represent lesions, 2) for images containing no lesions, no salient
region should be produced,and 3) lesions are generally small with relatively
smooth borders. We propose a new model-agnostic paradigm to interpret DLM
classification decisions supported by a novel definition of saliency that
incorporates the conditions above. Our model-agnostic 1-class saliency detector
(MASD) is tested on weakly supervised breast lesion detection from DCE-MRI,
achieving state-of-the-art detection accuracy when compared to current
visualization methods
Discovery of an HI Counterpart to the Extended Tail of Mira
We report the detection of an HI counterpart to the extended,
far-ultraviolet-emitting tail associated with the asymptotic giant branch star
Mira (o Ceti). Using the Nancay Radio Telescope (NRT), we have detected
emission as far as 88' north of the star, confirming that the tail contains a
significant atomic component (M_HI ~ 4x10e-3 M_sun). The NRT spectra reveal a
deceleration of the tail gas caused by interaction with the local interstellar
medium. We estimate an age for the tail of ~1.2x10e5 years, suggesting that the
mass-loss history of Mira has been more prolonged than previous observational
estimates. Using the Very Large Array (VLA) we have also imaged the HI tail out
to ~12' (0.4 pc) from the star. The detected emission shows a ``head-tail''
morphology, but with complex substructure. Regions with detected HI emission
correlate with far-ultraviolet-luminous regions on large scales, but the two
tracers are not closely correlated on smaller scales (<1'). We propose that
detectable tails of HI are likely to be a common feature of red giants
undergoing mass-loss.Comment: accepted to ApJ; version with full-resolution figures available at:
http://www.cfa.harvard.edu/~lmatthew/Mira_HI.pd
A reconnaissance-scale GIS-based multicriteria decision analysis to support sustainable biochar use: Poland as a case study
Although increasing numbers of research papers regarding biochar are being published worldwide, in some countries growing interest in biochar has only recently been observed; this is true of Poland. We analysed information on biochar research in Poland alongside lessons learned elsewhere in order to identify the significant opportunities and risks associated with biochar use. This data fed into a GIS-based multicriteria analysis to identify areas where biochar application could deliver greatest benefit. We found that 21.8% of agricultural land in Poland has at least moderate indication for biochar use (soil organic matter below 2% and pH below 5.5), while 1.5% was categorized as a priority as it also exhibited contamination. Potential barriers identified included biomass availability and associated risks of indirect land-use change due to possible national and transnational biomass production displacement. Biochar use could have positive global consequences as a climate change mitigation strategy, particularly relevant in a country with limited alternatives. Scaling up a mitigation technology that is viable on account of its co-benefits might be cost-effective, which could, in turn, adjust national perspectives and stronger involvement in developing mitigation policies at the regional level. Biochar has much promise in temperate conditions and further research should therefore be assigned to explore biochar’s environmental and socio-economic impacts
Photometric Monitoring of Open Clusters I. The Survey
Open clusters, which have age, abundance, and extinction information from
studies of main-sequence turn off stars, are the ideal location in which to
determine the mass-luminosity-radius relation for low-mass stars. We have
undertaken a photometric monitoring survey of open clusters in the Galaxy
designed to detect low-mass eclipsing binary systems through variations in
their relative light curves. Our aim is to provide an improved calibration of
the mass-luminosity-radius relation for low-mass stars and brown dwarfs, to
test stellar structure and evolution models, and to help quantify the
contribution of low-mass stars to the global mass census in the Galaxy. In this
paper we present our survey, describing the data and outlining the analysis
techniques. We study six nearby open clusters, with a range of ages from to 4 Gyr and metallicities from approximately solar to -0.2dex. We monitor
a field-of-view of > 1 square degree per target cluster, well beyond the
characteristic cluster radius, over timescales of hours, days, and months with
a sampling rate optimised for the detection of eclipsing binaries with periods
of hours to days. Our survey depth is designed to detect eclipse events in a
binary with a primary star of \lesssim 0.3~M_{\sun}. Our data have a
photometric precision of mmag at .Comment: 50 pages, 18 figures, accepted for publication in A
Profile of estetrol, a promising native estrogen for oral contraception and the relief of climacteric symptoms of menopause
Mariculture of the Asian kelp Undaria pinnatifida and the native kelp Saccharina lattisima along the Atlantic coast of southern Europe: An overview
Preprin
Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health
The article of record as published may be found at http://dx.doi.org/10.1093/sleep/zsab161Risks associated with fatigue that accumulates during work shifts have historically been managed through working time arrangements that specify fixed maximum durations of work shifts and minimum durations of time off. By themselves, such arrangements are not sufficient to curb risks to performance, safety, and health caused by misalignment between work schedules and the biological regulation of waking alertness and sleep. Science-based approaches for determining shift duration and mitigating associated risks, while addressing operational needs, require: 1) a recognition of the factors contributing to fatigue and fatigue-related risks; 2) an understanding of evidence-based countermeasures that may reduce fatigue and/or fatigue-related risks; and 3) an informed approach to selecting workplace-specific strategies for managing work hours. We propose a series of guiding principles to assist stakeholders with designing a shift duration decision-making process that effectively balances the need to meet operational demands with the need to manage fatigue-related risks.Academy of Sleep Medicine (AASM)Sleep Research Societ
Electronic learning can facilitate student performance in undergraduate surgical education: a prospective observational study
BACKGROUND: Our institution recently introduced a novel internet accessible computer aided learning (iCAL) programme to complement existing surgical undergraduate teaching methods. On graduation of the first full cycle of undergraduate students to whom this resource was available we assessed the utility of this new teaching facility. METHOD: The computer programme prospectively records usage of the system on an individual user basis. We evaluated the utilisation of the web-based programme and its impact on class ranking changes from an entry-test evaluation to an exit examination in surgery. RESULTS: 74.4% of students were able to access iCAL from off-campus internet access. The majority of iCAL usage (64.6%) took place during working hours (08:00–18:00) with little usage on the weekend (21.1%). Working hours usage was positively associated with improvement in class rank (P = 0.025, n = 148) but out-of hours usage was not (P = 0.306). Usage during weekdays was associated with improved rank (P = 0.04), whereas weekend usage was not (P = 0.504). There were no significant differences in usage between genders (P = 0.3). Usage of the iCAL system was positively correlated with improvement in class rank from the entry to the exit examination (P = 0.046). Students with lower ranks on entry examination, were found to use the computer system more frequently (P = 0.01). CONCLUSION: Electronic learning complements traditional teaching methods in undergraduate surgical teaching. Its is more frequently used by students achieving lower class ranking with traditional teaching methods, and this usage is associated with improvements in class ranking
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