1,213 research outputs found
Machine learning classification of entrepreneurs in British historical census data
This paper presents a binary classification of entrepreneurs in British historical data based on the recent availability of big data from the I-CeM dataset. The main task of the paper is to attribute an employment status to individuals that did not fully report entrepreneur status in earlier censuses (1851-1881). The paper assesses the accuracy of different classifiers and machine learning algorithms, including Deep Learning, for this classification problem. We first adopt a ground-truth dataset from the later censuses to train the computer with a Logistic Regression (which is standard in the literature for this kind of binary classification) to recognize entrepreneurs distinct from non-entrepreneurs (i.e. workers). Our initial accuracy for this base-line method is 0.74. We compare the Logistic Regression with ten optimized machine learning algorithms: Nearest Neighbors, Linear and Radial Support Vector Machine, Gaussian Process, Decision Tree, Random Forest, Neural Network, AdaBoost, Naive Bayes, and Quadratic Discriminant Analysis. The best results are boosting and ensemble methods. AdaBoost achieves an accuracy of 0.95. Deep-Learning, as a standalone category of algorithms, further improves accuracy to 0.96 without using the rich text-data that characterizes the OccString feature, a string of up to 500 characters with the full occupational statement of each individual collected in the earlier censuses. Finally, and now using this OccString feature, we implement both shallow (bag-of-words algorithm) learning and Deep Learning (Recurrent Neural Network with a Long Short-Term Memory layer) algorithms. These methods all achieve accuracies above 0.99 with Deep Learning Recurrent Neural Network as the best model with an accuracy of 0.9978. The results show that standard algorithms for classification can be outperformed by machine learning algorithms. This confirms the value of extending the techniques traditionally used in the literature for this type of classification problem.ESRC
Leverhulme Trust
Isaac Newton Trus
Circulating antigen tests and urine reagent strips for diagnosis of active schistosomiasis in endemic areas
Background:
Point-of-care (POC) tests for diagnosing schistosomiasis include tests based on circulating antigen detection and urine reagent strip tests. If they had sufficient diagnostic accuracy they could replace conventional microscopy as they provide a quicker answer and are easier to use.
Objectives:
To summarise the diagnostic accuracy of: a) urine reagent strip tests in detecting activeSchistosoma haematobium infection, with microscopy as the reference standard; and b) circulating antigen tests for detecting active Schistosoma infection in geographical regions endemic for Schistosoma mansoni or S. haematobium or both, with microscopy as the reference standard.
Search methods:
We searched the electronic databases MEDLINE, EMBASE, BIOSIS, MEDION, and Health Technology Assessment (HTA) without language restriction up to 30 June 2014.
Selection criteria
We included studies that used microscopy as the reference standard: for S. haematobium, microscopy of urine prepared by filtration, centrifugation, or sedimentation methods; and for S. mansoni, microscopy of stool by Kato-Katz thick smear. We included studies on participants residing in endemic areas only.
Data collection and analysis:
Two review authors independently extracted data, assessed quality of the data using QUADAS-2, and performed meta-analysis where appropriate. Using the variability of test thresholds, we used the hierarchical summary receiver operating characteristic (HSROC) model for all eligible tests (except the circulating cathodic antigen (CCA) POC for S. mansoni, where the bivariate random-effects model was more appropriate). We investigated heterogeneity, and carried out indirect comparisons where data were sufficient. Results for sensitivity and specificity are presented as percentages with 95% confidence intervals (CI).
Main results;
We included 90 studies; 88 from field settings in Africa. The median S. haematobiuminfection prevalence was 41% (range 1% to 89%) and 36% for S. mansoni (range 8% to 95%). Study design and conduct were poorly reported against current standards.
Tests for S. haematobium
Urine reagent test strips versus microscopy
Compared to microscopy, the detection of microhaematuria on test strips had the highest sensitivity and specificity (sensitivity 75%, 95% CI 71% to 79%; specificity 87%, 95% CI 84% to 90%; 74 studies, 102,447 participants). For proteinuria, sensitivity was 61% and specificity was 82% (82,113 participants); and for leukocyturia, sensitivity was 58% and specificity 61% (1532 participants). However, the difference in overall test accuracy between the urine reagent strips for microhaematuria and proteinuria was not found to be different when we compared separate populations (P = 0.25), or when direct comparisons within the same individuals were performed (paired studies; P = 0.21).
When tests were evaluated against the higher quality reference standard (when multiple samples were analysed), sensitivity was marginally lower for microhaematuria (71% vs 75%) and for proteinuria (49% vs 61%). The specificity of these tests was comparable.
Antigen assay
Compared to microscopy, the CCA test showed considerable heterogeneity; meta-analytic sensitivity estimate was 39%, 95% CI 6% to 73%; specificity 78%, 95% CI 55% to 100% (four studies, 901 participants).
Tests for S. mansoni
Compared to microscopy, the CCA test meta-analytic estimates for detecting S. mansoni at a single threshold of trace positive were: sensitivity 89% (95% CI 86% to 92%); and specificity 55% (95% CI 46% to 65%; 15 studies, 6091 participants) Against a higher quality reference standard, the sensitivity results were comparable (89% vs 88%) but specificity was higher (66% vs 55%). For the CAA test, sensitivity ranged from 47% to 94%, and specificity from 8% to 100% (four studies, 1583 participants).
Authors' conclusions:
Among the evaluated tests for S. haematobium infection, microhaematuria correctly detected the largest proportions of infections and non-infections identified by microscopy.
The CCA POC test for S. mansoni detects a very large proportion of infections identified by microscopy, but it misclassifies a large proportion of microscopy negatives as positives in endemic areas with a moderate to high prevalence of infection, possibly because the test is potentially more sensitive than microscopy
Effects of sequence variations in innate immune response genes on infectious outcome in trauma patients: A comprehensive review
Infectious complications, sepsis, and multiple organ dysfunction syndrome (MODS) remain important causes for morbidity and mortality in patients who survive the initial trauma. Increasing evidence suggests that genetic variants, particularly single nucleotide polymorphisms (SNPs), are critical determinants for interindividual differences in both inflammatory responses and clinical outcome in sepsis patients. Although the effect of SNPs on sepsis and MODS has been studied in many populations and diseases, this review aimed to summarize the current knowledge on the effect of SNPs on infectious complication specifically in trauma patients. A review of available literature was performed in PubMed database. The following genes have been studied in populations of trauma patients: CD14, HMGB1, IFNG, IL1A, IL1B, IL1RN, IL4, IL6, IL8, IL10, IL17F, IL18, MBL2, MASP2, FCN2, TLR1, TLR2, TLR4, TLR9, TNF, LTA, GR, MYLK, NLRP3, PRDX6, RAGE, HSPA1B, HSPA1L, HSP90, SERPINE1, IRAK1, IRAK3, VEGFA, LY96, ANGPT2, LBP, MicroRNA, and mtDNA. In this review, we discuss the genes of the Pattern Recognition Receptors, Signal Transducing Adaptor Proteins, and Inflammatory Cytokines of the innate immune system. A number of genetic variations have so far been studied in cohorts of trauma patients. Studies are often unique and numbers sometimes small. No definitive conclusions can be reached at this time about the influence of specific sequence variations on outcome in trauma patients
Multiple Infectious Complications in a Severely Injured Patient with Single Nucleotide Polymorphisms in Important Innate Immune Response Genes
Abstract
Trauma is a major public health problem worldwide. Infectious complications, sepsis, and multiple organ dysfunction syndrome (MODS) remain important causes for morbidity and mortality in patients who survive the initial trauma. There is increasing evidence for the role of genetic variation in the innate immune system on infectious complications in severe trauma patients. We describe a trauma patient with multiple infectious complications caused by multiple micro-organisms leading to prolonged hospital stay with numerous treatments. This patient had multiple single nucleotide polymorphisms (SNPs) in the MBL2, MASP2, FCN2 and TLR2 genes, most likely contributing to increased susceptibility and severity of infectious diseas
An Inner Gaseous Disk around the Herbig Be Star MWC 147
We present high-spectral-resolution, optical spectra of the Herbig Be star
MWC 147, in which we spectrally resolve several emission lines, including the
[O I] lines at 6300 and 6363\deg. Their highly symmetric, double-peaked line
profiles indicate that the emission originates in a rotating circumstellar
disk. We deconvolve the Doppler-broadened [O I] emission lines to obtain a
measure of emission as a function of distance from the central star. The
resulting radial surface brightness profiles are in agreement with a disk
structure consisting of a flat, inner, gaseous disk and a flared, outer, dust
disk. The transition between these components at 2 to 3 AU corresponds to the
estimated dust sublimation radius. The width of the double-peaked Mg II line at
4481\deg suggests that the inner disk extends to at least 0.10 AU, close to the
corotation radius.Comment: accepted for ApJ Letters (Oct. 2010
Reinsertion of an inverted osteochondral lesion of the talus: A case report
Osteochondral lesions of the talus (OLTs) occur infrequently and are missed at the initial presentation in up to 67% of cases. Probably more than 1500 OLTs have been reported in published studies, of which, thus far, only 5 cases have been an inverted anterolateral OLT. An anterolateral OLT results from a hypersupination trauma, in which the talar dome is caught behind the fibula. Apparently, if the forces are large enough a " flip of the coin" phenomenon occurs, causing the fragment to invert 180° upside down. We present the case of a young female patient with an inverted OLT that was treated with open reduction and internal fixation using bioabsorbable pins. Follow-up radiographs and computed tomography showed a congruent joint and complete healing of the osteochondral fragment. At the short-term follow-up visit, the functional outcome was promising
Luminosity- and morphology-dependent clustering of galaxies
How does the clustering of galaxies depend on their inner properties like
morphological type and luminosity? We address this question in the mathematical
framework of marked point processes and clarify the notion of luminosity and
morphological segregation. A number of test quantities such as conditional
mark-weighted two-point correlation functions are introduced. These descriptors
allow for a scale-dependent analysis of luminosity and morphology segregation.
Moreover, they break the degeneracy between an inhomogeneous fractal point set
and actual present luminosity segregation. Using the Southern Sky Redshift
Survey~2 (da Costa et al. 1998, SSRS2) we find both luminosity and
morphological segregation at a high level of significance, confirming claims by
previous works using these data (Benoist et al. 1996, Willmer et al. 1998).
Specifically, the average luminosity and the fluctuations in the luminosity of
pairs of galaxies are enhanced out to separations of 15Mpc/h. On scales smaller
than 3Mpc/h the luminosities on galaxy pairs show a tight correlation. A
comparison with the random-field model indicates that galaxy luminosities
depend on the spatial distribution and galaxy-galaxy interactions. Early-type
galaxies are also more strongly correlated, indicating morphological
segregation. The galaxies in the PSCz catalog (Saunders et al. 2000) do not
show significant luminosity segregation. This again illustrates that mainly
early-type galaxies contribute to luminosity segregation. However, based on
several independent investigations we show that the observed luminosity
segregation can not be explained by the morphology-density relation alone.Comment: aastex, emulateapj5, 20 pages, 13 figures, several clarifying
comments added, ApJ accepte
Botvervangende materialen
Abstract
Bone substitutes – In trauma and orthopedic surgery the use of autograft is a first choice therapy for filling bone defects. Due to drawbacks in the use of autografts (for example donor site morbidity and limited amount of bone tissue) there is an increasing interest in the use of (artificial) bone substitutes. This article provides an overview of the basic science of bone substitution. For optimal ingrowth of bone a transplant should have osteogenic, osteoinductive and osteoconductive characteristics. Bone substitutes are mostly osteoconductive and provide a scaffold for bone regeneration. Osteoconductivity is mainly determined by pore size, porosity and cristallinity. Calcium phosphates represent a group of bone substitutes that is being used mostly, and this group of products has been extensively studied. In addition, calcium sulphates and bioactive glass are used also. New developments such as the addition of growth factors to bone substitutes are under extensive research
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