1,466 research outputs found
Construction and Calibration of a Streaked Optical Spectrometer for Shock Temperature
Here we describe the implementation and calibration of a streaked visible
spectrometer (SVS) for optical pyrometry and emission/absorption spectroscopy
on light gas gun platforms in the UC Davis Shock Compression Laboratory. The
diagnostic consists of an optical streak camera coupled to a spectrometer to
provide temporally and spectrally-resolved records of visible emission from
dynamically-compressed materials. Fiber optic coupling to the sample enables a
small diagnostic footprint on the target face and flexibility of operation on
multiple launch systems without the need for open optics. We present the
details of calibration (time, wavelength and spectral radiance) for absolute
temperature determination and present benchmark measurements of system
performance.Comment: 6 pages, 3 figures Davies, E., et al. (accepted). In J. Lane, T.
Germann, and M. Armstrong (Eds.), 21st Biennial APS Conference on Shock
Compression of Condensed Matter (SCCM19). AIP Publishin
The effect of cancer stage and treatment modality on quality of life in oropharyngeal cancer
Objectives/Hypothesis To examine changes in health-related quality of life among oropharyngeal cancer patients by stages and across treatment types among advanced cancer patients. Study Design Individual prospective cohort study. Methods All newly diagnosed patients with oropharyngeal cancer treated with curative intent were routinely assessed. The European Organization for Research and Treatment of Cancer (EORTC) both the Main Module quality-of-life questionnaire (QLQ-C30) and the Head and Neck Cancer (HNC) Module (QLQ-H&N35) were administered at diagnosis and 3, 6, and 12 months thereafter. Complete case analysis was used following assessment of missing data. The proportion of patients with clinically significant deterioration (changes of ≥10 points) from baseline were calculated for each follow-up time point and compared by stage (I/II vs. III/IV) and then treatment type (chemotherapy and radiotherapy [CRT] vs. surgery and postoperative radiotherapy [S&PORT]). Results Deterioration in most domains was most frequent for stage III/IV patients at 3 months (both modules), whereas stage I/II patients experienced this at 6 months (QLQ-C30) and 12 months (H&N35). Among stage III/IV patients, this happened at all time points for S&PORT patients (QLQ-C30) versus 12 months for CRT patients (H&N35). The number of patients reporting deterioration was lower for most domains at 12 months compared to earlier periods, although dry mouth remained a problem for most patients (60%-85% across treatment/stage groups). Conclusions Our preliminary findings suggest that general and disease-specific deterioration is of most concern for stage I/II patients at 6 and 12 months and at 3 months for advanced cancer patients. For stage III/IV patients receiving S&PORT, general deterioration remains a problem after diagnosis, whereas for CRT patients, disease-specific deterioration is of most concern at 12 months. Level of Evidence 4. Laryngoscope, 124:151-158, 201
Magic Polygons and Their Properties
Magic squares are arrangements of natural numbers into square arrays, where
the sum of each row, each column, and both diagonals is the same. In this
paper, the concept of a magic square with 3 rows and 3 columns is generalized
to define magic polygons. Furthermore, this paper will examine the existence of
magic polygons, along with several other properties inherent to magic polygons.Comment: 7 pages, 4 figure
Microcalcification crystallography as a potential marker of DCIS recurrence
Ductal carcinoma in-situ (DCIS) accounts for 20–25% of all new breast cancer diagnoses. DCIS has an uncertain risk of progression to invasive breast cancer and a lack of predictive biomarkers may result in relatively high levels (~ 75%) of overtreatment. To identify unique prognostic biomarkers of invasive progression, crystallographic and chemical features of DCIS microcalcifications have been explored. Samples from patients with at least 5-years of follow up and no known recurrence (174 calcifications in 67 patients) or ipsilateral invasive breast cancer recurrence (179 microcalcifications in 57 patients) were studied. Significant differences were noted between the two groups including whitlockite relative mass, hydroxyapatite and whitlockite crystal maturity and, elementally, sodium to calcium ion ratio. A preliminary predictive model for DCIS to invasive cancer progression was developed from these parameters with an AUC of 0.797. These results provide insights into the differing DCIS tissue microenvironments, and how these impact microcalcification formation
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Impairment of perceptual metacognitive accuracy and reduced prefrontal grey matter volume in first-episode psychosis
Introduction: Metacognition, or “thinking about thinking”, is a higher-order thought process that allows for the evaluation of perceptual processes for accuracy. Metacognitive accuracy is associated with the grey matter volume (GMV) in the prefrontal cortex (PFC), an area also impacted in schizophrenia. The present study set out to investigate whether deficits in metacognitive accuracy are present in the early stages of psychosis.
Methods: Metacognitive accuracy in first-episode psychosis (FEP) was assessed on a perceptual decision making task and their performance compared to matched healthy control participants (N = 18). A novel signal detection theory approach was used to model metacognitive sensitivity independently from objective perceptual performance. A voxel-based morphometry investigation was also conducted on GMV.
Results: We found that the FEP group demonstrated significantly worse metacognitive accuracy compared to controls (p = .039). Importantly, GMV deficits were also observed in the superior frontal gyrus. The findings suggest a specific deficit in this processing domain to exist at first episode; however, no relationship was found between GMV and metacognitive accuracy.
Conclusions: Our findings support the notion that an inability to accurately scrutinise perception may underpin functional deficits observed in later schizophrenia; however, the exact neural basis of metacognitive deficits in FEP remains elusive
Evaluating human-AI interaction in the detection of lung, breast and colorectal cancers: a systematic scoping literature review
Background: In forthcoming years, Artificial Intelligence (AI) will become an increasingly integral part of medical imaging practice, and automated image interpretation, including Computer-Aided Detection (CADe), represents a particularly significant application of AI within this domain. It is, therefore, imperative that diagnostic radiographers develop an understanding of the role, value and potential pitfalls of using AI in medical image interpretation. Consequently, this paper reports findings from a systematic scoping literature review of studies addressing human-AI interaction in the detection of lung, breast and colorectal cancers.
Method: The Cochrane Central Register of Controlled Trials, PubMed and ScienceDirect were used to locate CADe observer performance studies in three reading paradigms: second-reader, concurrent and interactive. Conversant experimental studies were also retrieved. Key findings from a total of N=46 articles were extracted and organised according to reading paradigm and imaging modality.
Results: Aggregated evidence indicated that concurrent and second-reader CADe systems improved observer sensitivity, particularly among less experienced observers, but could also deleteriously affect attention allocation. Interactive CADe systems demonstrated a weaker impact upon observer sensitivity, though a smaller number of studies was available for analysis. Evidence also indicated that observer performance with CADe could be influenced by prompt design, level of participant expertise, lesion size and number of CAD false positives.
Conclusions: Concurrent and second-reader paradigms have equivalent potential to improve observer performance, though concurrent CADe is more time-efficient; an important consideration in practical clinical terms. Further research is needed to comprehensively understand the value of interactive CADe, particularly in volumetric imaging
A metabolic signature of long life in Caenorhabditis elegans
<p>Abstract</p> <p>Background</p> <p>Many <it>Caenorhabditis elegans </it>mutations increase longevity and much evidence suggests that they do so at least partly via changes in metabolism. However, up until now there has been no systematic investigation of how the metabolic networks of long-lived mutants differ from those of normal worms. Metabolomic technologies, that permit the analysis of many untargeted metabolites in parallel, now make this possible. Here we use one of these, <sup>1</sup>H nuclear magnetic resonance spectroscopy, to investigate what makes long-lived worms metabolically distinctive.</p> <p>Results</p> <p>We examined three classes of long-lived worms: dauer larvae, adult Insulin/IGF-1 signalling (IIS)-defective mutants, and a translation-defective mutant. Surprisingly, these ostensibly different long-lived worms share a common metabolic signature, dominated by shifts in carbohydrate and amino acid metabolism. In addition the dauer larvae, uniquely, had elevated levels of modified amino acids (hydroxyproline and phosphoserine). We interrogated existing gene expression data in order to integrate functional (metabolite-level) changes with transcriptional changes at a pathway level.</p> <p>Conclusions</p> <p>The observed metabolic responses could be explained to a large degree by upregulation of gluconeogenesis and the glyoxylate shunt as well as changes in amino acid catabolism. These responses point to new possible mechanisms of longevity assurance in worms. The metabolic changes observed in dauer larvae can be explained by the existence of high levels of autophagy leading to recycling of cellular components.</p> <p>See associated minireview: <url>http://jbiol.com/content/9/1/7</url></p
Neutrinos from Dark Matter annihilations at the Galactic Centre
We discuss the prospects for detection of high energy neutrinos from dark
matter annihilation at the Galactic centre. Despite the large uncertainties
associated with our poor knowledge of the distribution of dark matter in the
innermost regions of the Galaxy, we determine an upper limit on the neutrino
flux by requiring that the associated gamma-ray emission does not exceed the
observed flux. We conclude that if dark matter is made of neutralinos, a
neutrino flux from dark matter annihilations at the GC will not be observable
by Antares. Conversely, the positive detection of such a flux would either
require an alternative explanation, in terms of astrophysical processes, or the
adoption of other \DM candidates, disfavouring the case for neutralinos.Comment: 8 pages, 7 figures, submitted to PR
Tourism and the smartphone app: capabilities, emerging practice and scope in the travel domain.
Based on its advanced computing capabilities and ubiquity, the smartphone has rapidly been adopted as a tourism travel tool.With a growing number of users and a wide varietyof applications emerging, the smartphone is fundamentally altering our current use and understanding of the transport network and tourism travel. Based on a review of smartphone apps, this article evaluates the current functionalities used in the domestic tourism travel domain and highlights where the next major developments lie. Then, at a more conceptual level, the article analyses how the smartphone mediates tourism travel and the role it might play in more collaborative and dynamic travel decisions to facilitate sustainable travel. Some emerging research challenges are discussed
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