Graph-based methods are promising approaches for traditional and modern techniques in change detection (CD) applications. Nonetheless, some graph-based approaches omit the existence of useful priors ...that account for the structure of a scene, and the inter- and intra-relationships between the pixels are analyzed. To address this issue, in this article, we propose a framework for CD based on graph fusion and driven by graph signal smoothness representation. In addition to modifying the graph learning stage, in the proposed model, we apply a Gaussian mixture model for superpixel segmentation (GMMSP) as a downsampling module to reduce the computational cost required to learn the graph of the entire images. We carry out tests on 14 real cases of natural disasters, farming, and construction. The dataset contains homogeneous cases with multispectral (MS) and synthetic aperture radar (SAR) images, along with heterogeneous cases that include MS/SAR images. We compare our approach against probabilistic thresholding, unsupervised learning, deep learning, and graph-based methods. In terms of Cohen's kappa coefficient, our proposed model based on graph signal smoothness representation outperformed state-of-the-art approaches in ten out of 14 datasets.
Sensory processing circuits in the visual and olfactory systems receive input from complex, rapidly changing environments. Although patterns of light and plumes of odor create different distributions ...of activity in the retina and olfactory bulb, both structures use what appears on the surface similar temporal coding strategies to convey information to higher areas in the brain. We compare temporal coding in the early stages of the olfactory and visual systems, highlighting recent progress in understanding the role of time in olfactory coding during active sensing by behaving animals. We also examine studies that address the divergent circuit mechanisms that generate temporal codes in the two systems, and find that they provide physiological information directly related to functional questions raised by neuroanatomical studies of Ramon y Cajal over a century ago. Consideration of differences in neural activity in sensory systems contributes to generating new approaches to understand signal processing.
Gire, Restrepo, and coauthors compare temporal coding in the early stages of the olfactory and visual systems, highlighting the divergent circuit mechanisms that generate temporal codes in the two systems. Consideration of these differences contributes to generating new approaches to understand signal processing.
AbstractAlcohol-related liver disease (ALD) is a major cause of advanced chronic liver disease in Latin-America, although data on prevalence is limited. Public health policies aimed at reducing the ...alarming prevalence of alcohol use disorder in Latin-America should be implemented. ALD comprises a clinical-pathological spectrum that ranges from steatosis, steatohepatitis to advanced forms such as alcoholic hepatitis (AH), cirrhosis and hepatocellular carcinoma. Besides genetic factors, the amount of alcohol consumption is the most important risk factor for the development of ALD. Continuous consumption of more than 3 standard drinks per day in men and more than 2 drinks per day in women increases the risk of developing liver disease. The pathogenesis of ALD is only partially understood and recent translational studies have identified novel therapeutic targets. Early forms of ALD are often missed and most clinical attention is focused on AH, which is defined as an abrupt onset of jaundice and liver-related complications. In patients with potential confounding factors, a transjugular biopsy is recommended. The standard therapy for AH (i.e. prednisolone) has not evolved in the last decades yet promising new therapies (i.e. G-CSF, N-acetylcysteine) have been recently proposed. In both patients with early and severe ALD, prolonged abstinence is the most efficient therapeutic measure to decrease long-term morbidity and mortality. A multidisciplinary team including alcohol addiction specialists is recommended to manage patients with ALD. Liver transplantation should be considered in the management of patients with end-stage ALD that do not recover despite abstinence. In selected cases, increasing number of centers are proposing early transplantation for patients with severe AH not responding to medical therapy.
Relation among estuarine processes, mixing mechanisms and turbidity maximum zone (TMZ) formation was evaluated in a microtidal tropical estuary of high fluvial discharge (Magdalena River, ...northwestern South America). Particularly, assessing the effects of vertical stratification over mixing, estuarine circulation and suspended sediment transport processes. Measurements of salinity, temperature, density, currents and suspended sediment concentration (SSC) were performed at the Magdalena river mouth during high and low streamflows to distinguish among two contrasting seasonal conditions (flow conditions, wind patterns, wave energy). Salinity, temperature, density and location of the freshwater-saltwater interface (FSI) exhibited a sharp seasonal variability. The river mouth and delta front were stratified regardless of the hydrologic season, whereas the riverine section was stratified during the low streamflow season, reflecting the balance between fluvial advection and vertical stratification. Reduction of the vertical mixing led to a more clearly defined and extended stratification. Bottom friction is the main mixing mechanism, but as stratification is strengthened along the river mouth, the vertical mixing weakens, promoting the developing of TMZ (SSC >4500 mg l−1). Our results indicate that TMZ developing is caused by the convergence of stratified layers near the nodal point and the weakening of bottom turbulence by stratification. Although the TMZ exhibited a strong seasonal variation in its magnitude and extent, it usually formed in the convergence front demarcated by saltwater intrusion. Streamflow is the major influence on the TMZ formation since it allows the development of stratified conditions, which weaken turbulent mixing, and thus promotes particulate matter settling. The Magdalena River estuary can be classified as turbid (4000 mg l−1 < SSCmax < 10,000 mg l−1) and extremely turbid during low streamflow seasons (SSCmax > 10,000 mg l−1). These values are of the same order as the SSC reported for the Yangtze and Yellow estuaries, classified as having the largest SSC values of the world.
•Salinity, temperature, currents and suspended sediment concentration were measured at the Magdalena river mouth.•Relationship among estuarine processes, mixing mechanisms and turbidity maximum (TMZ) zone was evaluated.•Convergence of stratified layers, weakening of bottom turbulence and buoyancy effects promote development of TMZ.•Streamflow is the main influence on the TMZ formation, leading to stratified conditions that weakens turbulent mixing.•The Magdalena River estuary can be classified as extremely turbid during low streamflow seasons.
•These fluvial systems contribute 330km3yr−1 of freshwater into the Caribbean Sea.•From 2000 to 2010 the annual streamflow of these fluvial systems increased up to 65%.•A period of intense ...hydrological change was detected from 1998 to 2002.•The annual and quasi-decadal bands appear as the main oscillatory components.•ENSO-related band represents a second-order oscillatory component.
The monthly averaged freshwater discharge data from ten rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analysed to quantify the magnitudes, to estimate long-term trends, and to evaluate the variability of discharge patterns. These rivers deliver ∼340.9km3yr−1 of freshwater to the Caribbean Sea. The largest freshwater supply is provided by the Magdalena River, with a mean discharge of 205.1km3yr−1 at Calamar, which is 26% of the total fluvial discharge into this basin. From 2000 to 2010, the annual streamflow of these rivers increased as high as 65%, and upward trends in statistical significance were found for the Mulatos, Canal del Dique, Magdalena, and Fundación Rivers. The concurrence of major oscillation processes and the maximum power of the 3–7year band fluctuation defined a period of intense hydrological activity from approximately 1998–2002. The wavelet spectrum highlighted a change in the variability patterns of fluvial systems between 2000 and 2010 characterised by a shift towards a quasi-decadal process (8–12years) domain. The Intertropical Convergence Zone (ITCZ), El Niño – Southern Oscillation (ENSO) events, and quasi-decadal climate processes are the main factors controlling the fluvial discharge variability of these fluvial systems.
Current controversies in cholangiocarcinoma Hoyos, Sergio; Navas, Maria-Cristina; Restrepo, Juan-Carlos ...
Biochimica et biophysica acta. Molecular basis of disease,
April 2018, 2018-04-00, 20180401, Letnik:
1864, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Cholangiocarcinoma represents 10% of primary liver malignancies and accounts for less than 3% of all gastrointestinal malignant tumors, with an enormous geographical variation. This neoplasia can ...arise from the biliary tract epithelium or hepatic progenitor cells. Depending on the anatomic localization, it is classified into three subtypes: intrahepatic, perihilar and distal. This fact is one of the main difficulties, because there are many studies that indistinctly include the results in the management of these different types of cholangiocarcinoma, without differentiating its location and even including gallbladder cancer.
There are many controversial points in epidemiology, liver transplantation as a treatment, limitations of different results by group and type of treatment, histological testing and chemotherapy. This is a narrative review about topics in cholangiocarcinoma. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.
•Cholangiocarcinoma is the second most common primary liver cancer.•Cholangiocarcinoma is typically present in one of two ways: intrahepatic mass or as obstruction of large bile ducts.•It is difficult to establish the incidence and prevalence of this neoplasia due to the poor cancer registry.•The objetive in surgery for cholangiocarcinoma is to remove the entire tumor with disease-free margins.•Liver transplantation can be the treatment for some bile duct tumors in which there is a contraindication for liver resection.
Liver transplantation began in Colombia in 1979. It is one of the most active countries in this field in Latin America but has faced problems with the regulation and appropriate management of solid ...organ transplantations, including transplant tourism, which is a worldwide problem. There is a well‐structured donation and transplant network regulated by the government in all the stages of the process. In 2017, the country was ranked fourth for the number of liver transplantations (LTs) performed in Latin America, after Brazil, Argentina, and Uruguay, with a rate of 5.6 LTs per million population. Current regulatory bodies were created to coordinate and provide transparency and equality to transplant recipients. This article describes the evolution, government commissions, assignation criteria, and current status of LT in Colombia.
Critically ill patients can develop hyperglycaemia even if they do not have diabetes. Intensive insulin therapy decreases morbidity and mortality rates in patients in a surgical intensive care unit ...(ICU) and decreases morbidity in patients in a medical ICU. The effect of this therapy on patients in a mixed medical/surgical ICU is unknown. Our goal was to assess whether the effect of intensive insulin therapy, compared with standard therapy, decreases morbidity and mortality in patients hospitalised in a mixed ICU.
This is a prospective, randomised, non-blinded, single-centre clinical trial in a medical/surgical ICU. Patients were randomly assigned to receive either intensive insulin therapy to maintain glucose levels between 80 and 110 mg/dl (4.4 to 6.1 mmol/l) or standard insulin therapy to maintain glucose levels between 180 and 200 mg/dl (10 and 11.1 mmol/l). The primary end point was mortality at 28 days.
Over a period of 30 months, 504 patients were enrolled. The 28-day mortality rate was 32.4% (81 of 250) in the standard insulin therapy group and 36.6% (93 of 254) in the intensive insulin therapy group (Relative Risk RR: 1.1; 95% confidence interval CI: 0.85 to 1.42). The ICU mortality in the standard insulin therapy group was 31.2% (78 of 250) and 33.1% (84 of 254) in the intensive insulin therapy group (RR: 1.06; 95%CI: 0.82 to 1.36). There was no statistically significant reduction in the rate of ICU-acquired infections: 33.2% in the standard insulin therapy group compared with 27.17% in the intensive insulin therapy group (RR: 0.82; 95%CI: 0.63 to 1.07). The rate of hypoglycaemia (< or = 40 mg/dl) was 1.7% in the standard insulin therapy group and 8.5% in the intensive insulin therapy group (RR: 5.04; 95% CI: 1.20 to 21.12).
IIT used to maintain glucose levels within normal limits did not reduce morbidity or mortality of patients admitted to a mixed medical/surgical ICU. Furthermore, this therapy increased the risk of hypoglycaemia.
clinicaltrials.gov Identifiers: 4374-04-13031; 094-2 in 000966421.
The COVID-19 epidemic generated major changes in general surgical management protocols. The literature has reported high mortality rates for hip fracture surgery in patients with COVID-19. This study ...describes the morbidity and mortality in patients undergoing surgery due to hip fractures in 12 Colombian institutions between March and September 2020.
This was a retrospective observational descriptive study. Medical records of 12 hospitals were reviewed. Consecutive patients who underwent hip fracture surgery from March 6 to September 6, 2020, were included. Data collected were sociodemographic profile, type of fracture, surgical treatment, complications, and early (1 month) or mid-term (1-6 months) mortality associated or not with COVID-19.
Five hundred twenty patients with hip fractures requiring surgery in the 12 institutions were included. 364 (70%) were women; mean age was 77.7 years (SD: 13.8), mean BMI was 25.1, 91.73% of patients had at least one comorbidity, 60.38% were classified as ASA II and 25.77% as ASA III. There were 267 (51.34%) pertrochanteric fractures, 227 (43.65%) femoral neck fractures, and 26 (5.0%) subtrochanteric fractures. 274 (52.69%) patients were treated with osteosynthesis, 244 (46.92%) with arthroplasty, and 2 (0.38%) with girdlestone. Surgery was performed less than 24 h after the fracture for 115 (22.11%) patients, between 24 and 72 h for 208 (40.0%) patients, and more than 72 h for 197 (37.88%) patients. One hundred six patients in total suffered a medical or surgical complication throughout the different follow-up stages, amongst the most frequent were respiratory failure, coronary events, surgical site infection, cutting-out and peri‑implant fracture. 25 (4.8%) patients required attention in the Intensive Care Unit (ICU). 13 patients had COVID-19 throughout the follow-up period. 27 patients died due to any cause, and 3 of them had reported a positive COVID-19 test any time during follow-up period, of which one died during the first month, and two died between 1 and 6 months. Statistically significant associations were found between age older than 75 years old, ASA classification, ICU requirement, and death.
520 patients received surgical treatment for hip fracture during the first six months of the COVID-19 pandemic in 12 medical centers in Colombia. 21.10% suffered a complication during the early stage (30 days) and 4.77% during the midterm stage (1-6 months). 4.8% were admitted in the ICU during the early stage. All-cause death was 27 patients, early death was 11 (40.74%) and midterm death was 16 (59.25%). 13 patients were positive for COVID-19, 3 died, one (1/5=20%) on the first 30 days and the other two (2/8=25%) from month 1 to 6.
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