Análisis Comparativo del Posicionamiento Preciso Utilizando el Receptor de Bajo Costo GNSS ZED-F9P en Conjunto con la Antena BEIBT300 y Diferentes Modelos de Antena de Orden Geodésico

Con el avance de la Geodesia y la mejora de las especificaciones técnicas de los receptores de bajo costo, los GNSS abren nuevas alternativas para investigar las capacidades técnicas y rendimiento real que proveen este tipo de receptores para diferentes propósitos geodésicos. En este contexto, la precisión alcanzable fue analizada usando el receptor de bajo costo GNSS ZED-F9P en conjunto con dos antenas de orden geodésico (ASH701975.01B y LEIAS10 NONE) y una antena de bajo costo (BEIBT300 NONE). Las observaciones GNSS fueron llevadas a cabo en un periodo de dos días para cada modelo de antena. El análisis fue realizado en tiempos de observación de 12, 6 y 1 h, respectivamente. Estas observaciones fueron procesadas usando el método relativo estático mediante la inclusión de una estación de referencia continua del Instituto Nacional de Estadística y Geografía, la cual está localizada a una distancia aproximada de 4 km. Los resultados demuestran que la mayor precisión es lograda en un periodo de 12 h, con diferencias mínimas de 3 cm para la componente Norte y 33 cm para la vertical. En este sentido, la solución menos precisa es obtenida en el periodo de 1 h resultando diferencias de 70 cm, 46 cm y 2.3 m para la componente Norte, Este y vertical respectivamente.   With advancements in geodesy and enhancements in the technical specifications of low-cost receivers, GNSS opens up new avenues for investigating the capabilities and performance provided by these receivers for various geodetic purposes. In this context, the precision achievable using the low-cost GNSS receiver ZED-F9P in conjunction with two geodetic antennas (ASH701975.01B and LEIAS10 NONE) and a low-cost antenna (BEIBT300 NONE) was analyzed. GNSS observations were conducted over a 2-day period for each antenna model. The analysis involved observation durations of 12, 6, and 1 h. These observations were processed using the static relative method alongside a continuously operating GNSS station from the Active National Geodetic Network of the National Institute of Statistics and Geography, situated at ~4 km. The results demonstrate that the highest precision was achieved over a 12 h period, with minimal differences of 3 cm for the North component and 33 cm for the vertical component. Conversely, the least accurate solution was obtained within a 1 h observation period, resulting in differences of up to 70 cm, 46 cm, and 2.3 m for the North, East, and vertical components, respectively

A Comparison of the Effects of Random and Selective Mass Extinctions on Erosion of Evolutionary History in Communities of Digital Organisms

The effect of mass extinctions on phylogenetic diversity and branching history of clades remains poorly understood in paleobiology. We examined the phylogenies of communities of digital organisms undergoing open-ended evolution as we subjected them to instantaneous “pulse” extinctions, choosing survivors at random, and to prolonged “press” extinctions involving a period of low resource availability. We measured age of the phylogenetic root and tree stemminess, and evaluated how branching history of the phylogenetic trees was affected by the extinction treatments. We found that strong random (pulse) and strong selective extinction (press) both left clear long-term signatures in root age distribution and tree stemminess, and eroded deep branching history to a greater degree than did weak extinction and control treatments. The widely-used Pybus-Harvey gamma statistic showed a clear short-term response to extinction and recovery, but differences between treatments diminished over time and did not show a long-term signature. The characteristics of post-extinction phylogenies were often affected as much by the recovery interval as by the extinction episode itself

Real-world predictors of 12-month intravenous abatacept retention in patients with rheumatoid arthritis in the ACTION observational study

Introduction An understanding of real-world predictors of abatacept retention is limited. We analysed retention rates and predictors of abatacept retention in biologic-naive and biologic-failure patients in a 12-month interim analysis of the 2-year AbataCepTIn rOutiNe clinical practice (ACTION) study. Methods ACTION was an international, observational study of patients with moderate-to-severe rheumatoid arthritis (RA) who initiated intravenous abatacept. In this 12-month interim analysis, crude abatacept retention rates, predictors of retention and European League Against Rheumatism (EULAR) response were evaluated in both biologic-naive and biologic-failure patients. Retention by rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) status was also assessed, in patients with or without baseline radiographic erosions, and by body mass index (BMI). Results Overall, 2350/2364 enrolled patients were evaluable (674 biologic naive; 1676 biologic failure). Baseline characteristics were largely similar in biologic-naive and biologic-failure groups. Crude retention rates (95% CI) at 12 months were significantly higher in biologic-naive (78.1%(74.7% to 81.2%)) versus biologic-failure patients (69.9%(67.6% to 72.1%); P<0.001). RF/anti-CCP double positivity predicted higher retention in both patient groups, and remained associated with higher retention in patients with erosive disease. BMI did not impact abatacept retention in either patient group, irrespective of RF/anti-CCP serostatus. Good/moderate EULAR response rate at 12 months was numerically higher in biologic-naive (83.8%) versus biologic-failure (73.3%) patients. There were no new safety signals. Conclusion High levels of intravenous abatacept retention in clinical practice were confirmed, particularly in biologic-naive patients, including in those with poor RA prognostic factors. Retention was unaffected by BMI, regardless of RF/anti-CCP serostatus

Lesion detection in demoscopy images with novel density-based and active contour approaches

<p>Abstract</p> <p>Background</p> <p>Dermoscopy is one of the major imaging modalities used in the diagnosis of melanoma and other pigmented skin lesions. Automated assessment tools for dermoscopy images have become an important field of research mainly because of inter- and intra-observer variations in human interpretation. One of the most important steps in dermoscopy image analysis is the detection of lesion borders, since many other features, such as asymmetry, border irregularity, and abrupt border cutoff, rely on the boundary of the lesion. </p> <p>Results</p> <p>To automate the process of delineating the lesions, we employed Active Contour Model (ACM) and boundary-driven density-based clustering (BD-DBSCAN) algorithms on 50 dermoscopy images, which also have ground truths to be used for quantitative comparison. We have observed that ACM and BD-DBSCAN have the same border error of 6.6% on all images. To address noisy images, BD-DBSCAN can perform better delineation than ACM. However, when used with optimum parameters, ACM outperforms BD-DBSCAN, since ACM has a higher recall ratio.</p> <p>Conclusion</p> <p>We successfully proposed two new frameworks to delineate suspicious lesions with i) an ACM integrated approach with sharpening and ii) a fast boundary-driven density-based clustering technique. ACM shrinks a curve toward the boundary of the lesion. To guide the evolution, the model employs the exact solution <abbrgrp><abbr bid="B27">27</abbr></abbrgrp> of a specific form of the Geometric Heat Partial Differential Equation <abbrgrp><abbr bid="B28">28</abbr></abbrgrp>. To make ACM advance through noisy images, an improvement of the model’s boundary condition is under consideration. BD-DBSCAN improves regular density-based algorithm to select query points intelligently.</p

The effects of low-impact mutations in digital organisms

<p>Abstract</p> <p>Background</p> <p>Avida is a computer program that performs evolution experiments with digital organisms. Previous work has used the program to study the evolutionary origin of complex features, namely logic operations, but has consistently used extremely large mutational fitness effects. The present study uses Avida to better understand the role of low-impact mutations in evolution.</p> <p>Results</p> <p>When mutational fitness effects were approximately 0.075 or less, no new logic operations evolved, and those that had previously evolved were lost. When fitness effects were approximately 0.2, only half of the operations evolved, reflecting a threshold for selection breakdown. In contrast, when Avida's default fitness effects were used, all operations routinely evolved to high frequencies and fitness increased by an average of 20 million in only 10,000 generations.</p> <p>Conclusions</p> <p>Avidian organisms evolve new logic operations only when mutations producing them are assigned high-impact fitness effects. Furthermore, purifying selection cannot protect operations with low-impact benefits from mutational deterioration. These results suggest that selection breaks down for low-impact mutations below a certain fitness effect, the <it>selection threshold</it>. Experiments using biologically relevant parameter settings show the tendency for increasing genetic load to lead to loss of biological functionality. An understanding of such genetic deterioration is relevant to human disease, and may be applicable to the control of pathogens by use of lethal mutagenesis.</p

An automatic image analysis approach to quantify stained cell cultures.

Counting cells in culture is a common task in biotechnology research and production. This process should be automated to provide fast and objective quantification. Flow cytometry is adapted to count cells in suspension. However, the morphological information and the spatial organisation of adherent cells are lost when cells are removed from culture. This paper proposes a methodology based on image analysis to quantify stained nuclei in culture. The protocol is composed of several steps: cell staining, automatic microscopy imaging, segmentation by an automatic algorithm including a classification approach, and computation of quantitative data that characterizes the growth of cells. An evaluation shows that the automatic process of counting provides results similar to human manual counting. The major interests of the proposed approach are the fully automated processing and preservation of cell shapes and positions in culture. More than two thousand culture conditions have been measured by this tool for various applications including optimization of cell culture media, improvement of the culture processes and measurement of drug toxicity