Ensemble candidate classification for the LOTAAS pulsar survey

One of the biggest challenges arising from modern large-scale pulsar surveys is the number of candidates generated. Here, we implemented several improvements to the machine learning (ML) classifier previously used by the LOFAR Tied-Array All-Sky Survey (LOTAAS) to look for new pulsars via filtering the candidates obtained during periodicity searches. To assist the ML algorithm, we have introduced new features which capture the frequency and time evolution of the signal and improved the signal-to-noise calculation accounting for broad profiles. We enhanced the ML classifier by including a third class characterizing RFI instances, allowing candidates arising from RFI to be isolated, reducing the false positive return rate. We also introduced a new training data set used by the ML algorithm that includes a large sample of pulsars misclassified by the previous classifier. Lastly, we developed an ensemble classifier comprised of five different Decision Trees. Taken together these updates improve the pulsar recall rate by 2.5 per cent, while also improving the ability to identify pulsars with wide pulse profiles, often misclassified by the previous classifier. The new ensemble classifier is also able to reduce the percentage of false positive candidates identified from each LOTAAS pointing from 2.5 per cent (∼500 candidates) to 1.1 per cent (∼220 candidates)

A novel wideband dynamic directional indoor channel model based on a Markov process

This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available

Single-pulse classifier for the LOFAR Tied-Array All-sky Survey

Searches for millisecond-duration, dispersed single pulses have become a standard tool used during radio pulsar surveys in the last decade. They have enabled the discovery of two new classes of sources: rotating radio transients and fast radio bursts. However, we are now in a regime where the sensitivity to single pulses in radio surveys is often limited more by the strong background of radio frequency interference (RFI, which can greatly increase the false-positive rate) than by the sensitivity of the telescope itself. To mitigate this problem, we introduce the Single-pulse Searcher (SPS). This is a new machine-learning classifier designed to identify astrophysical signals in a strong RFI environment, and optimized to process the large data volumes produced by the new generation of aperture array telescopes. It has been specifically developed for the LOFAR Tied-Array All-Sky Survey (LOTAAS), an ongoing survey for pulsars and fast radio transients in the northern hemisphere. During its development, SPS discovered seven new pulsars and blindly identified ˜80 known sources. The modular design of the software offers the possibility to easily adapt it to other studies with different instruments and characteristics. Indeed, SPS has already been used in other projects, e.g. to identify pulses from the fast radio burst source FRB 121102. The software development is complete and SPS is now being used to re-process all LOTAAS data collected to date

Enhancing Mentoring in Palliative Care: An Evidence Based Mentoring Framework

Background: Growing concerns over ethical issues in mentoring in medicine and surgery have hindered efforts to reinitiate mentoring for Palliative Care (PC) physicians following the easing of COVID-19 restrictions. Ranging from the misappropriation of mentee’s work to bullying, ethical issues in mentoring are attributed to poor understanding and structuring of mentoring programs, underlining the need for a consistent approach to mentoring practices. Methods: Given diverse practices across different settings and the employ of various methodologies, a novel approach to narrative reviews (NR)s is proposed to summarize, interpret, and critique prevailing data on novice mentoring. To overcome prevailing concerns surrounding the reproducibility and transparency of narrative reviews, the Systematic Evidenced Based Approach (SEBA) adopts a structured approach to searching and summarizing the included articles and employed concurrent content and thematic analysis that was overseen by a team of experts. Results: A total of 18 915 abstracts were reviewed, 62 full text articles evaluated and 41 articles included. Ten themes/categories were ascertained identified including Nature; Stakeholders; Relationship; Approach; Environment; Benefits; Barriers; Assessments; Theories and Definitions. Conclusion: By compiling and scrutinizing prevailing practice it is possible to appreciate the notion of the mentoring ecosystem which sees each mentee, mentor, and host organization brings with them their own microenvironment that contains their respective goals, abilities, and contextual considerations. Built around competency based mentoring stages, it is possible to advance a flexible yet consistent novice mentoring framework. </jats:sec

Deploying Image Deblurring across Mobile Devices: A Perspective of Quality and Latency

Recently, image enhancement and restoration have become important applications on mobile devices, such as super-resolution and image deblurring. However, most state-of-the-art networks present extremely high computational complexity. This makes them difficult to be deployed on mobile devices with acceptable latency. Moreover, when deploying to different mobile devices, there is a large latency variation due to the difference and limitation of deep learning accelerators on mobile devices. In this paper, we conduct a search of portable network architectures for better quality-latency trade-off across mobile devices. We further present the effectiveness of widely used network optimizations for image deblurring task. This paper provides comprehensive experiments and comparisons to uncover the in-depth analysis for both latency and image quality. Through all the above works, we demonstrate the successful deployment of image deblurring application on mobile devices with the acceleration of deep learning accelerators. To the best of our knowledge, this is the first paper that addresses all the deployment issues of image deblurring task across mobile devices. This paper provides practical deployment-guidelines, and is adopted by the championship-winning team in NTIRE 2020 Image Deblurring Challenge on Smartphone Track.Comment: CVPR 2020 Workshop on New Trends in Image Restoration and Enhancement (NTIRE

Incidence and outcomes of delayed presentation and surgery in peritoneal surface malignancies

BackgroundPeritoneal surface malignancies (PSM) present insidiously and often pose diagnostic challenges. There is a paucity of literature quantifying the frequency and extent of therapeutic delays in PSM and its impact on oncological outcomes.MethodsA review of a prospectively maintained registry of PSM patients undergoing Cytoreductive Surgery and Hyperthermic Intra-peritoneal Chemotherapy (CRS-HIPEC) was conducted. Causes for treatment delays were identified. We evaluate the impact of delayed presentation and treatment delays on oncological outcomes using Cox proportional hazards models.Results319 patients underwent CRS-HIPEC over a 6-years duration. 58 patients were eventually included in this study. Mean duration between symptom onset and CRS-HIPEC was 186.0 ± 37.1 days (range 18-1494 days) and mean duration of between patient-reported symptom onset and initial presentation was 56.7 ± 16.8 days. Delayed presentation (&gt; 60 days between symptom onset and presentation) was seen in 20.7% (n=12) of patients and 50.0% (n=29) experienced a significant treatment delay of &gt; 90 days between 1st presentation and CRS-HIPEC. Common causes for treatment delays were healthcare provider-related i.e. delayed or inappropriate referrals (43.1%) and delayed presentation to care (31.0%). Delayed presentation was a significantly associated with poorer disease free survival (DFS) (HR 4.67, 95% CI 1.11-19.69, p=0.036).ConclusionDelayed presentation and treatment delays are common and may have an impact on oncological outcomes. There is an urgent need to improve patient education and streamline healthcare delivery processes in the management of PSM

The second set of pulsar discoveries by CHIME/FRB/Pulsar: 14 Rotating Radio Transients and 7 pulsars

The Canadian Hydrogen Mapping Experiment (CHIME) is a radio telescope located in British Columbia, Canada. The large field of view (FOV) of $\sim$ 200 square degrees has enabled the CHIME/FRB instrument to produce the largest FRB catalog to date. The large FOV also allows CHIME/FRB to be an exceptional pulsar and Rotating Radio Transient (RRAT) finding machine, despite saving only the metadata information of incoming Galactic events. We have developed a pipeline to search for pulsars/RRATs using DBSCAN, a clustering algorithm. Output clusters are then inspected by a human for pulsar/RRAT candidates and follow-up observations are scheduled with the more sensitive CHIME/Pulsar instrument. The CHIME/Pulsar instrument is capable of a near-daily search mode observation cadence. We have thus developed the CHIME/Pulsar Single Pulse Pipeline to automate the processing of CHIME/Pulsar search mode data. We report the discovery of 21 new Galactic sources, with 14 RRATs, 6 regular slow pulsars and 1 binary system. Owing to CHIME/Pulsar's daily observations we have obtained timing solutions for 8 of the 14 RRATs along with all the regular pulsars. This demonstrates CHIME/Pulsar's ability at finding timing solutions for transient sources

Exosomal microRNAs in the development of essential hypertension and its potential as biomarkers

MicroRNAs (miRNAs) are small regulatory molecules that are involved in posttranscriptional modifications. These noncoding RNAs are usually ferried by extracellular carriers such as exosomes or other protein and lipid carriers inside a range of body fluids including plasma and urine. Due to their ability to withstand harsh external conditions, exosomal miRNAs possess enormous potential as noninvasive disease biomarkers for, notably hypertension, whereby exosomal miRNAs have been implicated in its pathophysiological processes. More importantly, alterations in the microenvironment as a result of disease progression can induce active and selective loading of miRNAs into exosomes. In this paper, we first review the mechanisms of miRNA loading into exosomes, followed by the roles of exosomal miRNAs in the development of hypertension, and the potentials of exosomal miRNAs as biomarkers in comparison with other free circulating miRNAs. Finally, challenges and future research surrounding exosomal miRNAs will also be discussed. This review will aid in the understanding of noninvasive biomarkers for the early diagnosis of hypertension and for probing therapeutic efficacy

Multiwavelength Constraints on the Origin of a Nearby Repeating Fast Radio Burst Source in a Globular Cluster

Since fast radio bursts (FRBs) were discovered, their precise origins have remained a mystery. Multiwavelength observations of nearby FRB sources provide one of the best ways to make rapid progress in our understanding of the enigmatic FRB phenomenon. We present results from a sensitive, broadband multiwavelength X-ray and radio observational campaign of FRB 20200120E, the closest known extragalactic repeating FRB source. At a distance of 3.63 Mpc, FRB 20200120E resides in an exceptional location, within a ~10 Gyr-old globular cluster in the M81 galactic system. We place deep limits on both the persistent X-ray luminosity and prompt X-ray emission at the time of radio bursts from FRB 20200120E, which we use to constrain possible progenitors for the source. We compare our results to various classes of X-ray sources and transients. In particular, we find that FRB 20200120E is unlikely to be associated with: ultraluminous X-ray bursts (ULXBs), similar to those observed from objects of unknown origin in other extragalactic globular clusters; giant flares, like those observed from Galactic and extragalactic magnetars; or most intermediate flares and very bright short X-ray bursts, similar to those seen from magnetars in the Milky Way. We show that FRB 20200120E is also unlikely to be powered by a persistent or transient ultraluminous X-ray (ULX) source or a young, extragalactic pulsar embedded in a Crab-like nebula. We also provide new constraints on the compatibility of FRB 20200120E with accretion-based FRB models involving X-ray binaries and models that require a synchrotron maser process from relativistic shocks to generate FRB emission. These results highlight the power that multiwavelength observations of nearby FRBs can provide for discriminating between potential FRB progenitor models.Comment: 58 pages, 10 figures, 7 tables, submitte

A systematic scoping review of approaches to teaching and assessing empathy in medicine

10.1186/s12909-021-02697-6BMC Medical Education21129