1,822 research outputs found

    Evaluation of Xgboost and Lgbm Performance in Tree Species Classification with Sentinel-2 Data

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    Los, H., Mendes, G. S., Cordeiro, D., Grosso, N., Costa, H., Benevides, P., & Caetano, M. (2021). Evaluation of Xgboost and Lgbm Performance in Tree Species Classification with Sentinel-2 Data. In IGARSS 2021 - 2021 IEEE International Geoscience and Remote Sensing Symposium: Proceedings (pp. 5803-5806). IEEE. https://doi.org/10.1109/IGARSS47720.2021.9553031Tree species classification with satellite data has become more and more popular since Sentinel-2 launch. We compared efficacy and effectiveness of Extreme Gradient Boosting (XGBoost) and Light Gradient Boosting Machine (LGBM) with widely used in remote sensing Random Forest (RF), Support Vector Machine (SVM) and K-Nearest Neighbour (KNN) algorithms. Analyses were performed over an area in Portugal with multi-temporal Sentinel-2 data registered in April, June, August and October 2018. The selected classes were: cork oak, holm oak, eucalyptus, other broadleaved, maritime pine, stone pine and other coniferous. Algorithm efficacy was measured through F1-score and accuracy while efficiency was measured through the median time needed for each fit. XGBoost and LGBM outperformed efficacy of other algorithms, which was already high (above 90% for the best variant of each algorithm). In terms of efficacy, LGBM overcame all algorithms, including XGBoost.authorsversionpublishe

    Comparison between two bone substitutes for alveolar ridge preservation after tooth extraction: Cone-beam computed tomography results of a non-inferiority randomized controlled trial

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    AIM To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to DBBM with 10% collagen (DBBM-C) for maintenance of bone volume after tooth extraction in the anterior maxilla. MATERIALS AND METHODS Sixty-six patients were randomly treated with DBBM or DBBM-C, both of which were covered with a collagen matrix for ridge preservation in the anterior maxilla. Cone-beam computed tomographic analysis was performed immediately and 4 months after treatment. The primary outcome, for which non-inferiority of DBBM was tested, was change in the horizontal ridge width 1 mm below the buccal alveolar crest (HW-1) 4 months after extraction. RESULTS Four months after extraction, HW-1 measured -1.60 mm ± 0.82 mm for DBBM-C, while the DBBM group showed a mean loss of -1.37 mm ± 0.84 mm (p = 0.28, 0.23 [95% CI: -0.19; 0.64]). The horizontal ridge width at 3 mm (HW-3) showed -0.98 mm (±0.67 mm) for DBBM-C and -0.84 mm (±0.62 mm) for DBBM (p = 0.40, 0.12 [95% CI: -0.19; 0.45]), and the horizontal ridge width at 5 mm (HW-5) showed -0.67 mm (±0.47 mm) for DBBM-C and -0.56 mm (±0.48 mm) for DBBM (p = 0.36, 0.11 [95% CI: -0.13; 0.34]). CONCLUSIONS The present clinical trial demonstrated non-inferiority of DBBM compared to DBBM-C for maintenance of alveolar bone volume 4 months after tooth extraction in the anterior maxilla

    Body mass index as a predictor of the presence but not the severity of coronary artery disease evaluated by cardiac computed tomography

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    Background The relation between body mass index (BMI) and coronary artery disease (CAD) extension remains controversial. The aim of this study was to evaluate the correlation between BMI and CAD extension documented by coronary computed tomography angiography (CCTA). Methods and results Prospective registry including 1706 consecutive stable patients that performed CCTA (dual source scanner) for the evaluation of CAD. The population was stratified by BMI: normal 530 (31.1\%), overweight 802 (47.0\%) and obesity 374 (21.9\%). BMI was significantly higher in patients with CAD (27.74.3vs 26.8 +/- 4.3kg/m(2), p5 segments with plaque (15.4\% patients). The prevalence of SIS >5 among the BMI classes was: 18.7\%, 13.7\% and 13.6\% for normal, overweight and obesity respectively (p values for the specific classes versus all other patients: 0.241, 0.450 and 0.663). Conclusions In this population of stable patients undergoing CCTA for suspected CAD, BMI was an independent predictor of its presence, but was not correlated with the coronary disease severity.publishersversionpublishe

    ICES. 2019. Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA).

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    The Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA1) met by correspondence from 3 to 7 June 2019, and in Madrid from the 25 to the 28 of November 2019, and was chaired by Alexandra Silva (Portugal). There were 13 participants from France, Portugal, Spain and UK. The main task of WGHANSA was to assess the status the stocks of sardine in the Celtic Seas and English Channel (pil.27.7), sardine in the Bay of Biscay (pil.27.8abd), sardine in the Cantabrian Sea and Atlantic Iberian waters (pil.27.8c9a), anchovy in the Bay of Biscay (ane.27.8), anchovy in Atlantic Iberian waters (ane.27.9a; components west and south), horse mackerel in Atlantic Iberian waters (hom.27.9a) and jack mackerel in the Azores (jaa.27.10). Assessments and short-term forecasts were updated according to the stock annexes. There is no assessment method adopted for pil.27.7 due to the lack of data. The stock of pil.27.8abd was assessed as category 1 for the first time, following an interbenchmark. Recruitment has been above the average, the spawning–stock biomass declined and fishing mortality steeply increased in 2010–2012. SSB is fluctuating above MSY Btrigger and F2018 is above FMSY and below Fpa. This year, the DEPM datapoint for 2017 was included in the pil.27.9a assessment for the first time, following a revision of the survey data. The stock has decreased since 2006 and stabilized to a historical low since 2012. The biomass of age 1 and older fish has been decreasing since 2006 and reached the lowest historical value in 2015. It has since increased slightly but is below Blim since 2011. Recruitment has been below the time-series average since 2005. Recruitment in 2018 was around the geometric mean of the last five years. Fishing mortality has been decreasing from a peak in 2011. In 2018, it was the lowest in the time-series and below Fpa and Flim. The stock size indicator for anchovy in 9a.west decreased 90% from 2018 to 2019 (4129 t), after a period of an increasing trend since 2014. The harvest rate decreased 67% from management year 2017 to 2018 being below the median of the historical time-series.The relative spawning–stock biomass of the south component of the anchovy 9.a stock has fluctuated without a trend over the time-series, with most of the values above Bpa. From 2018 to 2019, the relative SSB decreased 5% but is still well above Bpa. Relative Fishing mortality (F) has fluctuated with no clear trend. From management year 2017 to 2018, relative F decreased 93%. The SSB of horse mackerel in Division 9.a fluctuated from 1992, the beginning of the assessment period, to 2012–2013 and afterwards increased continuously to a historical maximum, in 2018. The consistently high recruitment since 2011 has contributed to the SSB increase. Fishing mortality was 0.029 year -1 in 2018, showing a 29% decrease compared to 2017. Fishing mortality has been below FMSY over the whole time-series. The spawning–stock biomass has been above MSY Btrigger over the whole time-series. The exploration of data on anchovy abundance-at-age from juvenile surveys IBERAS-JUVESAR and ECOCADIZ-RECLUTAS indicated the series are still short to conclude about their future incorporation into the assessments. The analyses of internal consistency of the indices and of their consistency with spring acoustic surveys showed promising results for ECOCADIZ-RECLUTAS and pointed out the need to revisit the results of some of the surveys, particularly the IBERAS_JUVESAR series. For sardine, 0-group abundance from IBERAS-JUVESAR (2013–2019) combined with data from an earlier autumn survey, SAR-PT-AUT (discontinued in 2008) covering the northwestern Iberian waters, showed a significant correlation with the abundance of age 1 individuals in surveys carried out in the following spring

    Prevalence and predictors of coronary artery disease in patients with a calcium score of zero

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    The absence of coronary calcification is associated with an excellent prognosis. However, a calcium score of zero does not exclude the presence of coronary artery disease (CAD) or the possibility of future cardiovascular events. Our aim was to study the prevalence and predictors of coronary artery disease in patients with a calcium score of zero. Prospective registry consisted of 3,012 consecutive patients that underwent cardiac CT (dual source CT). Stable patients referred for evaluation of possible CAD that had a calcium score of zero (n = 864) were selected for this analysis. The variables that were statistically significant were included in a multivariable logistic regression model. From 864 patients with a calcium score of zero, 107 (12.4 %) had coronary plaques on the contrast CT (10.8 %, n = 93 with nonobstructive CAD and 1.6 %, n = 14 with obstructive CAD). By logistic regression analysis, the independent predictors of CAD in this population were age >55 years [odds ratio (OR) 1.63 (1.05-2.52)], hypertension [OR 1.64 (1.05-2.56)] and dyslipidemia [OR 1.54 (1.00-2.36)]. In the presence of these 3 variables, the probability of having coronary plaques was 21 %. The absence of coronary artery calcification does not exclude the presence of coron

    Coronary computed tomography angiography-adapted Leaman score as a tool to noninvasively quantify total coronary atherosclerotic burden

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    To describe a coronary computed tomography angiography (CCTA)-adapted Leaman score (CT-LeSc) as a tool to quantify total coronary atherosclerotic burden with information regarding localization, type of plaque and degree of stenosis and to identify clinical predictors of a high coronary atherosclerotic burden as assessed by the CT-LeSc. Single center prospective registry including a total of 772 consecutive patients undergoing CCTA (Dual-source CT) from April 2011 to March 2012. For the purpose of this study, 581 stable patients referred for suspected coronary artery disease (CAD) without previous myocardial infarction or revascularization procedures were included. Pre-test CAD probability was determined using both the Diamond-Forrester extended CAD consortium method (DF-CAD consortium model) and the Morise score. Cardiovascular risk was assessed with the HeartScore. The cut-off for the 3rd tercile (CT-LeSc ≥8.3) was used to define a population with a high coronary atherosclerotic burden. The median CT-LeSc in this population (n = 581, 8,136 coronary segments evaluated; mean age 57.6 ± 11.1; 55.8 % males; 14.6 % with diabetes) was 2.2 (IQR 0-6.8). In patients with CAD (n = 341), the median CT-LeSc was 5.8 (IQR 3.2-9.6). Among patients with nonobstructive CAD, most were classified in the lowest terciles (T1, 43.0 %; T2, 36.1 %), but 20.9 % were in the highest tercile (T3). The majority of the patients with obstructive CAD were classified in T3 (78.2 %), but 21.8 % had a CT-LeSc in lower terciles (T1 or T2). The independent predictors of a high CT-LeSc were: Male sex (OR 1.73; 95 % CI 1.04-2.90) diabetes (OR 2.91; 95 % CI 1.61-5.23), hypertension (OR 2.54; 95 % CI 1.40-4.63), Morise score ≥16 (OR 1.97; 95 % CI 1.06-3.67) and HeartScore ≥5 (OR 2.42; 95 % CI 1.41-4.14). We described a cardiac CT adapted Leaman score as a tool to quantify total (obstructive and nonobstructive) coronary atherosclerotic burden, reflecting the comprehensive information about localization, degree of stenosis and type of plaque provided by CCTA. Male sex, hypertension, diabetes, a HeartScore ≥5 % and a Morise score ≥16 were associated with a high coronary atherosclerotic burden, as assessed by the CT-LeSc. About one fifth of the patients with nonobstructive CAD had a CT-LeSc in the highest tercile, and this could potentially lead to a reclass

    Diabetes as an independent predictor of high atherosclerotic burden assessed by coronary computed tomography angiography: The coronary artery disease equivalent revisited

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    (1) To study the prevalence and severity of coronary artery disease (CAD) in diabetic patients. (2) To provide a detailed characterization of the coronary atherosclerotic burden, including the localization, degree of stenosis and plaque composition by coronary computed tomography angiography (CCTA). Single center prospective registry including a total of 581 consecutive stable patients (April 2011-March 2012) undergoing CCTA (Dual-source CT) for the evaluation of suspected CAD without previous myocardial infarction or revascularization procedures. Different coronary plaque burden indexes and plaque type and distribution patterns were compared between patients with (n = 85) and without diabetes (n = 496). The prevalence of CAD (any plaque; 74.1 vs. 56 %; p = 0.002) and obstructive CAD (≥50 % stenosis; 31.8 vs. 10.3 %; p<0.001) were significantly higher in diabetic patients. The remaining coronary atherosclerotic burden indexes evaluated (plaque in LM-3v-2v with prox. LAD; SIS; SSS; CT-LeSc) were also significantly higher in diabetic patients. In the per segment analysis, diabetics had a higher percentage of segments with plaque in every vessel (2.6/13.1/7.5/10.5 % for diabetics vs. 1.4/7.1/3.3/4.4 % for nondiabetics for LM, LAD, LCx, RCA respectively; p<0.001 for all) and of both calcified (19.3 vs. 9.2 %, p<0.001) and noncalcified or mixed types (14.4 vs. 7.0 %; p<0.001); the ratio of proximal-to-distal relative plaque distribution (calculated as LM/proximal vs. mid/distal/branches) was lower for diabetics (0.75 vs. 1.04; p = 0.009). Diabetes was an independent predictor of CAD and was also associated with more advanced CAD, evaluated by indexes of coronary atherosclerotic burden. Diabetics had a significantly higher prevalence of plaques in every anatomical subset and for the different plaque composition. In this report, the relative geographic distribution of the plaques within each subgroup, favored a more mid-to-distal localization in the diabetic patients

    Working Group for the Bay of Biscay and the Iberian Waters Ecoregion (ICES WGBIE) (2-9 May 2109)

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    The ICES Working Group for the Bay of Biscay and the Iberian Waters Ecoregion (WGBIE) assesses the status of 23 stocks distributed from ICES Divisions 3.a–4.a though to Subarea 9, mostly distributed in Subareas 7, 8 and 9. The group was tasked with conducting assessments of stock status for 23 stocks using analytical, forecast methods or trends indicators to provide catch forecasts and a first draft of the ICES advice for 2019. For two of the Nephrops stocks updates were provided on catch data with the advice release delayed until October after the completion of the surveys used for the assessment. Analytical assessments using age-structured models were conducted for the northern stock of white anglerfish, the northern and southern stocks of megrim, four-spot megrim and sole in the Bay of Biscay. The two hake stocks and one southern stock of anglerfish were assessed using models that allow the use of length-structured data (no age data). A surplus-production model, without age or length structure, was used to assess the second southern stock of anglerfish and an age-length structure model was used for the European seabass in the Bay of Biscay. The state of stocks for which no analytical assessment could be performed was inferred from examination of catch, commercial LPUE or CPUE data and from survey information, where available. The northern stock of hake was benchmarked this year to incorporate discards into the model that were previously omitted. New reference points with the accepted benchmark assessment were proposed by the group and new proxy biomass reference points where proposed for black anglerfish in Division’s 7b-k, 8abd. A recurrent issue significantly constrained the group’s ability to fully address the terms of reference this year. Despite an ICES data call with a deadline of six weeks before the meeting, data for most stocks were submitted to ICES only two days before the start of the meeting and in one case 2 days after the meeting commenced. This delayed the process of having the data quality checked and the assessment completed before the start of the working group. This is an important matter of concerns for the working group members. The structure of the report is set out with section 1 presenting a summary of each stock, discussing general issues and conclusions. Section 2 provides descriptions of the relevant fishing fleets and surveys used in the assessment of the stocks. Sections 3–18 contains the single stock assessments
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