922017 research outputs found
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The Magnetic Field in the Milky Way Filamentary Bone G47
No full textStar formation primarily occurs in laments where magnetic fields are expected to be dynamicallyimportant. The largest and densest laments trace spiral structure within galaxies. Over a dozen ofthese dense (∼10 4 cm-3) and long (>10 pc) laments have been found within the Milky Way, and they are often referred to as 'bones." Until now, none of these bones have had their magnetic field resolved and mapped in their entirety. We introduce the SOFIA legacy project FIELDMAPS which has begun mapping ∼10 of these Milky Way bones using the HAWC+ instrument at 214 μm and 18:002 resolution. Here we present a first result from this survey on the ∼60 pc long bone G47. Contrary to some studies of dense laments in the Galactic plane, we find that the magnetic field is often not perpendicular to the spine (i.e., the center-line of the bone). Fields tend to be perpendicular in the densest areas of active star formation and more parallel or random in other areas. The average field is neither parallel or perpendicular to the Galactic plane nor the bone. The magnetic field strengths along the spine typically vary from ∼20 to ∼100 μG. Magnetic fields tend to be strong enough to suppress collapse along much of the bone, but for areas that are most active in star formation, the fields are notably less able to resist gravitational collapse.<br/
SonOpt: Sonifying Bi-objective Population-Based Optimization Algorithms
No full textWe propose SonOpt, the first (open source) data sonification application for monitoring the progress of bi-objective populationbased optimization algorithms during search, to facilitate algorithm understanding. SonOpt provides insights into convergence/stagnation of search, the evolution of the approximation set shape, location of recurring points in the approximation set, and population diversity. The benefits of data sonification have been shown for various non-optimization related monitoring tasks. However, very few attempts have been made in the context of optimization and their focus has been exclusively on single-objective problems. In comparison, SonOpt is designed for biobjective optimization problems, relies on objective function values ofnon-dominated solutions only, and is designed with the user (listener) in mind; avoiding convolution of multiple sounds and prioritising ease of familiarizing with the system. This is achieved using two sonification paths relying on the concepts of wavetable and additive synthesis.This paper motivates and describes the architecture of SonOpt, and then validates SonOpt for two popular multi-objective optimization algorithms (NSGA-II and MOEA/D). Experience SonOpt yourself viahttps://github.com/tasos-a/SonOpt-1.0.Keywords: sonification · optimization · algorithmic behaviour · metaheuristics · evolutionary computation · process monitoring · SonOpt
Effect of low pressure plasma surface modification on filtration performance of chitosan nanofibrous respiratory filter
No full textLow pressure drop is highly desirable for respiratory filters. Surface activation plays an important role to enhance the filtration performance of respiratory filters. In this study, a three-layer composite respiratory filter was developed using a combination of polypropylene (PP) nonwoven layers and chitosan nanofibres (CSNF) with variable coating time (h) during the electrospinning process. To study the impact of surface activation on filtration performance, the outer surface of all the samples were modified using low-pressure plasma treatment. Filtration performance testing was conducted to determine the filtration efficiency (%), pressure drop (Pa), and quality factor (Q) results, before and after the surface treatment. The maximum values of filtration efficiency and quality factor achieved were 99.99% and 0.068, respectively. The lowest value of the pressure drop was 16.12 Pa. All the low-pressure plasma-treated samples showed higher filtration efficiency and quality factor compared to untreated samples due to a more effective capturing mechanism. However, pressure drop results indicated no significant difference. Furthermore, the decay of plasma treatment impact was analysed by using drop shape analysis method to measure the water contact angle on the surface of the samples. Results showed a gradual decrease in surface modification impact and the surface of the treated samples changed from hydrophilic to hydrophobic with the passage of time.</p
Clinical challenges associated with utility of neoadjuvant treatment in patients with pancreatic ductal adenocarcinoma
No full textPancreatic ductal adenocarcinoma (PDAC) is an increasingly common cancer with a persistently poor prognosis, and only approximately 20% of patients are clearly anatomically resectable at diagnosis. Historically, a paucity of effective therapy made it inappropriate to forego the traditional gold standard of upfront surgery in favour of neoadjuvant treatment; however, modern combination chemotherapy regimens have made neoadjuvant therapy increasingly viable. As its use has expanded, the rationale for neoadjuvant therapy has evolved from one of `downstaging` to one of early treatment of micro-metastases and selection of patients with favourable tumour biology for resection. Defining resectability in PDAC is problematic; multiple differing definitions exist. Multidisciplinary input, both in initial assessment of resectability and in supervision of multimodality therapy, is therefore advised. European and North American guidelines recommend the use of neoadjuvant chemotherapy in borderline resectable (BR)-PDAC. Similar regimens may be applied in locally advanced (LA)-PDAC with the aim of improving potential access to curative-intent resection, but appropriate patient selection is key due to significant rates of recurrence after excision of LA disease. Upfront surgery and adjuvant chemotherapy remain standard-of-care in clearly resectable PDAC, but multiple trials evaluating the use of neoadjuvant therapy in this and other localised settings are ongoing
ADBSat: Verification and validation of a novel panel method for quick aerodynamic analysis of satellites
No full textWe present the validation of ADBSat, a novel implementation of the panel method including a fast pseudo-shading algorithm, that can quickly and accurately determine the forces and torques on satellites in free-molecular flow. Our main method of validation is comparing test cases between ADBSat, the current de facto standard of direct simulation Monte Carlo (DSMC), and published literature. ADBSat exhibits a significantly shorter runtime than DSMC and performs well, except where deep concavities are present in the satellite models. The shading algorithm also experiences problems when a large proportion of the satellite surface area is oriented parallel to the flow, but this can be mitigated by examining the body at small angles to this configuration (± 0.1◦). We recommend that an error interval on ADBSat outputs of up to 3% is adopted. Therefore, ADBSat is a suitable tool for quickly determining the aerodynamic characteristics of a wide range of satellite geometries in different environmental conditions in VLEO. It can also be used in a complementary manner to identify cases that warrant further investigation using other numerical-based methods.<br/
21 new long-term variables in the GX 339−4 field: two years of MeerKAT monitoring
No full textWe present 21 new long-term variable radio sources found commensally in two years of weekly MeerKAT monitoring of the low-mass X-ray binary GX 339−4. The new sources vary on time scales of weeks to months and have a variety of light curveshapes and spectral index properties. Three of the new variable sources are coincident with multi-wavelength counterparts; and one of these is coincident with an optical source in deep MeerLICHT images. For most sources, we cannot eliminate refractive scintillation of active galactic nuclei as the cause of the variability. These new variable sources represent 2.2 ± 0.5 per cent of the unresolved sources in the field, which is consistent with the 1-2 per cent variability found in past radio variability surveys. However, we expect to find short-term variable sources in the field as well as these 21 new long-term variable sources. We present the radio light curves and spectral index variability of the new variable sources, as well as the absolute astrometry and matches to coincident sources at other wavelengths
Impact and control of fouling in radioactive environments.
No full textFouling and scaling of equipment in the nuclear industry is a significant and challenging problem that effects multiple areas across the entire nuclear fuel cycle. Consequences such as the blockage of fluid flow, accumulation of radionuclides, reduction of heat-transfer energy and enhancement of corrosion, all can have detrimental effects on safety and performance as well as incurring substantial damage and maintenance costs amounting to billions of pounds a year. This review focuses on pipelines and understanding the mechanisms of formation and radionuclide incorporation of inorganic and biological fouling, and microbially influenced corrosion (MIC) mechanisms, as well as exploring prevalent examples in the nuclear industry and parallels in the oil and gas industries. The review will also cover advancements in fouling and scale mitigation and treatment strategies, which are imperative to reduce economic loses and avoid safety hazards in nuclear as well as many other industries
Evaluating and Updating a Design Space for Augmented Reality Television
No full textAs Augmented Reality Television (ARTV) transitions out of the feasibility phase, it is crucial to understand the impact of designdecisions on the viewers’ ARTV experiences. In a previous study, six ARTV design dimensions were identified by relying on insightsfrom existing prototypes. However, the set of possible dimensions is likely to be broader. Building on top of previous work, wecreate an ARTV design space and present it in a textual cheat sheet. We subsequently evaluate the cheat sheet in a between-subjectstudy (𝑛 = 10), with participants with wide-ranging expertise. We identified six new dimensions (genre, broadcast mode, audiencedemographics, cartoonish vs. photoreal representation, modality, and privacy), and a new aspect (360◦) for the display dimension. Inlight of our observations, we provide an updated ARTV design space and observe that asking participants to write ARTV scenarioscan be an effective method for harvesting novel design dimensions
Clinical outcome and underlying genetic cause of functional terminal complement pathway deficiencies in a multi-center UK cohort
No full textBackground: Terminal complement pathway deficiencies often present with severe and recurrent infections. There is a lack of good quality data on these rare conditions. This study investigated the clinical outcome and genetic variation in a large UK multi-center cohort with primary and secondary terminal complement deficiencies. Methods: Clinicians from seven UK centers provided anonymised demographic, clinical and laboratory data on patients with terminal complement deficiencies, which were collated and analysed. Results: Forty patients, median age 19 (range 3 62) years, were identified with terminal complement deficiencies. Ten (62%) of 16 patients with low serum C5 concentrations had underlying pathogenic CFH or CFI gene variants. Two-thirds were from consanguineous Asian families and 80% had an affected family member. The median age of first infection was nine years. Forty-three percent suffered meningococcal serotype B, and 43% serotype Y infections. Nine (22%) were treated in intensive care for meningococcal septicemia. Two patients had died, one from intercurrent COVID-19. Twenty-one (52%) were asymptomatic and diagnosed based on family history. All but one patient had received booster meningococcal vaccines and 70% were taking prophylactic antibiotics. Discussion: The genetic etiology and clinical course of patients with primary and secondary terminal complement deficiency is variable. Patients with low antigenic C5 concentrations require genetic testing, as the low level may reflect consumption secondary to regulatory defects in the pathway. Screening of siblings is important. Only half of patients develop septicemia, but all should have a clear management plan. Key words: terminal complement pathway; Factor H; Factor I; meningococcal infection; genetic