We describe changes in the cropland distribution for physiographic and bioregions of continental Ecuador between 2000 and 2016 using Landsat satellite data and government statistics. The cloudy ...conditions in Ecuador are a major constraint to satellite data analysis. We developed a two-stage cloud filtering algorithm to create cloud-free multi-temporal Landsat composites that were used in a Random Forest model to identify cropland. The overall accuracy of the model was 78% for the Coast region, 86% for the Andes, and 98% for the Amazon region. Cropland density was highest in the coastal lowlands and in the Andes between 2500 and 4400 m. During this period, cropland expansion was most pronounced in the Páramo, Chocó Tropical Rainforests, and Western Montane bioregions. There was no cropland expansion detected in the Eastern Foothill forests bioregion. The satellite data analysis further showed a small contraction of cropland (4%) in the Coast physiographic region, and cropland expansion in the Andes region (15%), especially above 3500m, and in the Amazon region (57%) between 2000 and 2016. The government data showed a similar contraction for the Coast (7%) but, in contrast with the satellite data, they showed a large agricultural contraction in the Andes (39%) and Amazon (50%). While the satellite data may be better at estimating relative change (trends), the government data may provide more accurate absolute numbers in some regions, especially the Amazon because separating pasture and tree crops from forest with satellite data is challenging. These discrepancies illustrate the need for careful evaluation and comparison of data from different sources when analyzing land use change.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Thiamine pyrophosphate (TPP), an essential co‐factor for all species, is biosynthesised through a metabolically expensive pathway regulated by TPP riboswitches in bacteria, fungi, plants and ...green algae. Diatoms are microalgae responsible for c. 20% of global primary production. They have been predicted to contain TPP aptamers in the 3′UTR of some thiamine metabolism‐related genes, but little information is known about their function and regulation.
We used bioinformatics, antimetabolite growth assays, RT‐qPCR, targeted mutagenesis and reporter constructs to test whether the predicted TPP riboswitches respond to thiamine supplementation in diatoms. Gene editing was used to investigate the functions of the genes with associated TPP riboswitches in Phaeodactylum tricornutum.
We found that thiamine‐related genes with putative TPP aptamers are not responsive to supplementation with thiamine or its precursor 4‐amino‐5‐hydroxymethyl‐2‐methylpyrimidine (HMP), and targeted mutation of the TPP aptamer in the THIC gene encoding HMP‐P synthase does not deregulate thiamine biosynthesis in P. tricornutum. Through genome editing we established that PtTHIC is essential for thiamine biosynthesis and another gene, PtSSSP, is necessary for thiamine uptake.
Our results highlight the importance of experimentally testing bioinformatic aptamer predictions and provide new insights into the thiamine metabolism shaping the structure of marine microbial communities with global biogeochemical importance.
Studying land use change in protected areas (PAs) located in tropical forests is a major conservation priority due to high conservation value (e.g., species richness and carbon storage) here, coupled ...with generally high deforestation rates. Land use change researchers use a variety of land cover products to track deforestation trends, including maps they produce themselves and readily available products, such as the Global Forest Change (GFC) dataset. However, all land cover maps should be critically assessed for limitations and biases to accurately communicate and interpret results. In this study, we assess deforestation in PA complexes located in agricultural frontiers in the Amazon Basin. We studied three specific sites: Amboró and Carrasco National Parks in Bolivia, Jamanxim National Forest in Brazil, and Tambopata National Reserve and Bahuaja-Sonene National Park in Peru. Within and in 20km buffer areas around each complex, we generated land cover maps using composites of Landsat imagery and supervised classification, and compared deforestation trends to data from the GFC dataset. We then performed a dissimilarity analysis to explore the discrepancies between the two remote sensing products. Both the GFC and our supervised classification showed that deforestation rates were higher in the 20km buffer than inside the PAs and that Jamanxim National Forest had the highest deforestation rate of the PAs we studied. However, GFC maps showed consistently higher rates of deforestation than our maps. Through a dissimilarity analysis, we found that many of the inconsistencies between these datasets arise from different treatment of mixed pixels or different parameters in map creation (for example, GFC does not detect reforestation after 2012). We found that our maps underestimated deforestation while GFC overestimated deforestation, and that true deforestation rates likely fall between our two estimates. We encourage users to consider limitations and biases when using or interpreting our maps, which we make publicly available, and GFC’s maps.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper presents a novel method of searching for boosted hadronically decaying objects by treating them as anomalous elements of a contaminated dataset. A Variational Recurrent Neural Network ...(VRNN) is used to model jets as sequences of constituent four-vectors. After applying a pre-processing method which boosts each jet to the same reference mass, energy, and orientation, the VRNN provides each jet an Anomaly Score that distinguishes between the structure of signal and background jets. The model is trained in an entirely unsupervised setting and without high level variables, making the score more robust against mass and p T correlations when compared to methods based primarily on jet substructure. Performance is evaluated on the jet level, as well as in an analysis context by searching for a heavy resonance with a final state of two boosted jets. The Anomaly Score shows consistent performance along a wide range of signal contamination amounts, for both two and three-pronged jet substructure hypotheses. Analysis results demonstrate that the use of Anomaly Score as a classifier enhances signal sensitivity while retaining a smoothly falling background jet mass distribution. The model's discriminatory performance resulting from an unsupervised training scenario opens up the possibility to train directly on data without a pre-defined signal hypothesis.
Promoting remyelination is considered as a potential neurorepair strategy to prevent/limit the development of permanent neurological disability in patients with multiple sclerosis (MS). To this end, ...a number of clinical trials are investigating the potential of existing drugs to enhance oligodendrocyte progenitor cell (OPC) differentiation, a process that fails in chronic MS lesions. We previously reported that oligodendroglia express GABAB receptors (GABABRs) both in vitro and in vivo, and that GABABR‐mediated signaling enhances OPC differentiation and myelin protein expression in vitro. Our goal here was to evaluate the pro‐remyelinating potential of GABABR agonist baclofen (Bac), a clinically approved drug to treat spasticity in patients with MS. We first demonstrated that Bac increases myelin protein production in lysolecithin (LPC)‐treated cerebellar slices. Importantly, Bac administration to adult mice following induction of demyelination by LPC injection in the spinal cord resulted in enhanced OPC differentiation and remyelination. Thus, our results suggest that Bac repurposing should be considered as a potential therapeutic strategy to stimulate remyelination in patients with MS.
Main Points
Baclofen enhances myelin protein synthesis in cerebellar organotypic cultures demyelinated with lysolecithin (LPC).
Baclofen increases oligodendrocyte progenitor cell (OPC) differentiation and remyelination in demyelinated lesions from spinal cord in adult mice.
Thoracic endovascular aortic repair (TEVAR) has become the most common surgical procedure for treatment of descending thoracic aortic pathology. Cervical debranching in the form of carotid–subclavian ...bypass or transposition (CSBT) and carotid–carotid bypass (CCB) has enabled the use of TEVAR for the treatment of more complex anatomy involving the arch. The present study examined the effects of concomitant cervical bypass on the perioperative outcomes of TEVAR.
The American College of Surgeons National Surgical Quality Improvement Program files (2005-2017) were reviewed. Using the Current Procedural Terminology codes, all patients who had undergone TEVAR were identified and were divided into three groups: TEVAR, TEVAR with one bypass (CSBT or CCB), and TEVAR with two bypasses (CSBT and CCB). The patient characteristics and perioperative outcomes of the three groups were compared. Multivariable analysis was performed to determine the factors associated with mortality.
A total of 3281 patients had undergone TEVAR and 10% had also undergone one or more debranching procedure (one bypass, 9%; two bypasses, 1%). The frequency of debranching had increased from 3.4% to 10.9% (P = .01) during the study period. Significant differences were found among the three groups in age, sex, smoking history, urgency of surgery, and anesthesia technique. The patients who had undergone TEVAR with cervical debranching had had significantly greater morbidity, longer operating times, and longer hospital stays compared with those who had undergone TEVAR alone. The mortality of TEVAR with two bypasses (22.6%) was significantly greater than that of TEVAR alone (7.5%) and TEVAR with one bypass (6.8%; P < .01). The total morbidity (30.9% vs 35.1% vs 67.7%; P < .001) and stroke rate (3% vs 7.5% vs 12.9%; P < .0001) increased with the increasing number of bypasses. A subgroup analysis of patients who had undergone TEVAR with one bypass showed no significant differences in mortality between TEVAR plus CSBT (6.6%) vs TEVAR plus CCB (8.8%; P = .63). Multivariable analysis showed that TEVAR with two bypasses was associated with significantly increased mortality compared with TEVAR alone (odds ratio OR, 4.33; 95% confidence interval CI, 1.75-10.73) and TEVAR with one bypass (OR, 3.44; 95% CI, 1.24-9.51). Older age (OR, 1.74; 95% CI, 1.42-2.13), dependent functional status (OR, 1.48; 1.00-2.19), dialysis (OR, 2.61; 95% CI, 1.57-4.33), and emergent status (OR, 3.66; 95% CI, 2.73-4.90) were also associated with mortality.
TEVAR with concomitant cervical debranching has been increasingly used to treat complex aortic pathology but is associated with significantly worse outcomes than TEVAR alone. As advanced endovascular technology to treat the aortic arch emerges, the outcomes of open surgical debranching in the present study constitute an important benchmark for comparison.
Blends of different PTFE fine powder resins have been prepared and extruded in an attempt of improving the PTFE paste extrusion process and/or the extrudates. The extrusion pressure and the ...mechanical properties of the extrudates were found to fall between those exhibited by the pure components. While this is an expectable behavior, it offers opportunities for controlling the degree of fibrillation needed in the final products by mixing highly fibrillated with low fibrillated PTFE resins. Boron nitride and organically modified montmorillonite clays (solid lubricants) are also tested as additives to the lubricants used in the PTFE paste extrusion in order to identify enhanced processing aids. It was found that the addition of boron nitride and clays increase the extrusion pressure but at the same time improve the mechanical properties of the final extrudates in most cases. This again offers possibilities for controlling the final mechanical properties by controlling the degree of fibrillation, i. e., by adding a small amount of solid lubricants to adjust pressure, fibrillation, and thus the final mechanical properties. Finally, it is shown that fibrillation depends on temperature. Moreover, the mechanical properties of extrudates increase as the temperature goes through its two transition temperatures of 19 °C and 30 °C that render PTFE particles more deformable and prone to fibrillation.
Abstract Objective Distal embolization (DE) during peripheral arterial endovascular interventions is a well-known complication that is poorly studied. The goal of this study was to determine the ...incidence, risk factors, and effect of DE on the outcomes of lower extremity endovascular interventions (LEIs). Methods All LEIs between 2010 and 2014 in the Vascular Study Group of New England (VSGNE) database were reviewed. Patient characteristics were analyzed to determine predictors of DE. LEIs involving the superficial femoral artery (SFA) were reviewed to assess the effect of type of treatment on DE. The outcomes examined were loss of patency, limb loss, and mortality after LEI involving the SFA. A multivariable regression was used to determine predictors of DE. Results There were 10,875 procedures. The incidence of DE was 17.3 per 1000 procedures, and 68% required treatment (57% endovascular, 11% open surgery). DE was more common in patients treated for critical limb ischemia compared with claudication (relative risk RR, 2.06; 95% confidence interval CI, 1.24-3.45; P = .006) and for emergency interventions compared with elective (RR, 2.98; 95% CI, 1.22-7.30; P = .017). DE increased with the number of arteries treated ( P < .0001) and with the length of occlusion ( P < .0001). The SFA was the most commonly treated artery (4751 43.7%). In comparison with atherectomy and balloon angioplasty, stenting alone (RR, 0.36; 95% CI, 0.17-0.73; P = .005), balloon angioplasty alone (RR, 0.23; 95% CI, 0.13-0.41; P < .0001), and combined stenting and balloon angioplasty (RR, 0.29; 95% CI, 0.17-0.49; P < .0001) were associated with a significantly lower risk of DE. DE was not significantly associated with loss of patency, major amputation, or mortality. Conclusions The incidence of DE during LEIs is 1% to 2% in the VSGNE database, and most patients are treated with additional endovascular interventions. The incidence increases in patients with critical limb ischemia and with the use of atherectomy.
Anticipated perioperative morbidity is an important factor for choosing a revascularization method for chronic limb-threatening ischemia (CLTI). Our goal was to assess systemic perioperative ...complications of patients treated with surgical and endovascular revascularization in the Best Endovascular vs Best Surgical Therapy in Patients with CLTI (BEST-CLI) trial.
BEST-CLI was a prospective randomized trial comparing open (OPEN) and endovascular (ENDO) revascularization strategies for patients with CLTI. Two parallel cohorts were studied: Cohort 1 included patients with adequate single-segment great saphenous vein (SSGSV), whereas Cohort 2 included those without SSGSV. Data were queried for major adverse cardiovascular events (MACE–composite myocardial infarction, stroke, death), non-serious (non-SAEs) and serious adverse events (SAEs) (criteria–death/life-threatening/requiring hospitalization or prolongation of hospitalization/significant disability/incapacitation/affecting subject safety in trial) 30 days after the procedure. Per protocol analysis was used (intervention received without crossover), and risk-adjusted analysis was performed.
There were 1367 patients (662 OPEN, 705 ENDO) in Cohort 1 and 379 patients (188 OPEN, 191 ENDO) in Cohort 2. Thirty-day mortality in Cohort 1 was 1.5% (OPEN 1.8%; ENDO 1.3%) and in Cohort 2 was 1.3% (2.7% OPEN; 0% ENDO). MACE in Cohort 1 was 4.7% for OPEN vs 3.13% for ENDO (P = .14), and in Cohort 2, was 4.28% for OPEN and 1.05% for ENDO (P = .15). On risk-adjusted analysis, there was no difference in 30-day MACE for OPEN vs ENDO for Cohort 1 (hazard ratio HR 1.5; 95% confidence interval CI, 0.85-2.64; P = .16) or Cohort 2 (HR, 2.17; 95% CI, 0.48-9.88; P = .31). The incidence of acute renal failure was similar across interventions; in Cohort 1 it was 3.6% for OPEN vs 2.1% for ENDO (HR, 1.6; 95% CI, 0.85-3.12; P = .14), and in Cohort 2, it was 4.2% OPEN vs 1.6% ENDO (HR, 2.86; 95% CI, 0.75-10.8; P = .12). The occurrence of venous thromboembolism was low overall and was similar between groups in Cohort 1 (OPEN 0.9%; ENDO 0.4%) and Cohort 2 (OPEN 0.5%; ENDO 0%). Rates of any non-SAEs in Cohort 1 were 23.4% in OPEN and 17.9% in ENDO (P = .013); in Cohort 2, they were 21.8% for OPEN and 19.9% for ENDO (P = .7). Rates for any SAEs in Cohort 1 were 35.3% for OPEN and 31.6% for ENDO (P = .15); in Cohort 2, they were 25.5% for OPEN and 23.6% for ENDO (P = .72). The most common types of non-SAEs and SAEs were infection, procedural complications, and cardiovascular events.
In BEST-CLI, patients with CLTI who were deemed suitable candidates for open lower extremity bypass surgery had similar peri-procedural complications following either OPEN or ENDO revascularization: In such patients, concern about risk of peri-procedure complications should not be a deterrent in deciding revascularization strategy. Rather, other factors, including effectiveness in restoring perfusion and patient preference, are more relevant.
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The auxin‐inducible degron (AID) is a useful technique to rapidly deplete proteins of interest in nonplant eukaryotes. Depletion is achieved by addition of the plant hormone auxin to the cell ...culture, which allows the auxin‐binding receptor, TIR1, to target the AID‐tagged protein for degradation by the proteasome. Fast depletion of the target protein requires good expression of TIR1 protein, but as we show here, high levels of TIR1 may cause uncontrolled depletion of the target protein in the absence of auxin. To enable conditional expression of TIR1 to a high level when required, we regulated the expression of TIR1 using the β‐estradiol expression system. This is a fast‐acting gene induction system that does not cause secondary effects on yeast cell metabolism. We demonstrate that combining the AID and β‐estradiol systems results in a tightly controlled and fast auxin‐induced depletion of nuclear target proteins. Moreover, we show that depletion rate can be tuned by modulating the duration of β‐estradiol preincubation. We conclude that TIR1 protein is a rate‐limiting factor for target protein depletion in yeast, and we provide new tools that allow tightly controlled, tuneable, and efficient depletion of essential proteins whereas minimising secondary effects.
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