Fuel treatment effects on tree-based forest carbon storage and emissions under modeled wildfire scenarios

Forests are viewed as a potential sink for carbon (C) that might otherwise contribute to climate change. It is unclear, however, how to manage forests with frequent fire regimes to maximize C storage while reducing C emissions from prescribed burns or wildfire. We modeled the effects of eight different fuel treatments on tree-based C storage and release over a century, with and without wildfire. Model runs show that, after a century of growth without wildfire, the control stored the most C. However, when wildfire was included in the model, the control had the largest total C emission and largest reduction in live-tree-based C stocks. In model runs including wildfire, the final amount of tree-based C sequestered was most affected by the stand structure initially produced by the different fuel treatments. In wildfire-prone forests, tree-based C stocks were best protected by fuel treatments that produced a low-density stand structure dominated by large, fire resistant pines

Saisonnalité du transport de carbone organique dissous dans le ruisseau de l'Hermine, un bassin versant de tête de réseau du Bouclier Canadien

Nous avons étudié la variabilité saisonnière de la relation entre les fluctuations des concentrations en carbone organique dissous (COD) dans le ruisseau de l'Hermine (Québec, Canada) et les changements du débit (Q). Un total de 93 événements hydrologiques échantillonnés de 1994 à 2003 et regroupés sur une base saisonnière (hiver-printemps, été, automne) a été analysé. Le modèle de régression linéaire est utilisé afin de déterminer, pour chaque événement, la pente de la relation entre la concentration en COD dans le ruisseau et le débit. Ces pentes sont regroupées par saison et selon un seuil arbitraire de un qui permet de contraster les conditions hydrologiques et climatiques initiales des événements répertoriés. Les résultats du test de Kruskal-Wallis, visant la comparaison entre les événements de pentes supérieures et inférieures à un, montrent clairement la saisonnalité de la relation entre le COD et le débit. La saisonnalité de la relation COD/Q est ensuite mise en relation avec des variables climatiques et hydrologiques susceptibles de conditionner le transport du COD dans le bassin de l'Hermine. Les résultats montrent que les changements saisonniers des conditions climatiques et hydrologiques dans le bassin versant ont un impact significatif sur la relation entre le COD et le débit. Ainsi, le volume de précipitation tombé durant l'événement, la température moyenne de l'air et la température du sol régissent significativement (p =0,041; 0,001 et 0,009 respectivement) le transport du COD pour la période hiver-printemps. Les basses températures du sol et l'apport élevé en eau via les précipitations et la fonte favorisent le lessivage intense du COD soluble déjà limité par les basses températures. Au cours de l'été, l'état initial d'humidité du bassin est le principal facteur contrôlant l'évolution des concentrations de COD lors d'une crue; les fortes relations avec le pourcentage d'humidité des sols et le débit total 24 h avant l'événement le prouvent (p =0,039 et 0,0003 respectivement). Les changements les plus prononcés du COD surviennent, au cours de l'été, suite à une période prolongée de sécheresse. À l'automne, le transport du COD est influencé par le volume de précipitation tombé durant l'événement (p =0,031) et la température du sol (p =0,042). La modélisation de la relation COD/Q par les variables hydro-climatiques montre que 40% de la relation COD/Q s'explique par la température du sol durant la période d'hiver-printemps. Durant l'été, les conditions initiales d'humidité du bassin, traduites par le débit 24 h avant l'événement, expliquent à 51% la relation COD/Q. À l'automne, la relation COD/Q est gouvernée à 50% à la fois par le volume de précipitation tombé durant l'événement et la température du sol. L'analyse de ces données établit clairement la saisonnalité de la relation COD/Q et que des variables climatiques et hydrologiques permettent de quantifier ces fluctuations saisonnières.The terrestrial organic carbon (C) pool, estimated to 1.5 x 1015 kg C for the first meter of soil (Amundson, 2001), represents a major terrestrial elemental stock for which the recycling rate and the response to perturbations are still unknown. Under the present changing climatic conditions, C fluxes in terrestrial ecosystems could be significantly disturbed during the next decades. Indeed, the multi-annual changes in temperature and precipitation are likely to have a major impact on the net primary production and on organic matter decomposition in soils. This situation influences the production of the dissolved organic carbon (DOC) in soils, its transport to surface waters and hence, water quality. In this context, a better knowledge of the climatic and hydrologic factors influencing seasonal variations in DOC export is crucial to improve our understanding of the potential transformation of carbon stocks and fluxes in terrestrial ecosystems.The objectives of the present study were 1) to evaluate the seasonality in the relationship between dissolved organic carbon (DOC) concentrations in the stream and streamflow (Q) and 2) to quantify the impact of seasonal changes in climatic and hydrological conditions in the watershed on the DOC/Q relationship.The Hermine catchment is located about 80 km north of Montréal, Québec, Canada. An intermittent first-order stream drains the 5.1 ha catchment. Soils are Orthic and Gleyed Humo-Ferric and Ferro-Humic Podzols. The stream water was sampled daily, from 1994 to 2003, with an automatic sampler. The stream discharge was calculated from the water level above a 90º V-notch weir using a Global level sensor bubbler. Soil organic C content was analysed by the modified Walkley-Black method. Because of the high cost of DOC analysis for numerous samples, the DOC content was estimated by the relationship obtained between eight stream water samples analysed with a Shimadzu TOC analyser (Shimadzu, Kyoto, Japan) and the corresponding absorbance measured at 254 nm. From the initial year of the project, 1994, the regression used was Y=-0.05 + 32.60 X with an r2 value of 0.58 and a precision of 0.05 mg·L-1.The relationship between the DOC concentration and Q at the Hermine was positive and significant (p < 0.01) when all data were considered (n=1960). Because of the weakness of this relation (r2 =0.12), the stream samples, from 1994 to 2003, were seasonally split into 93 distinct hydrological events: 33 for winter-spring, 34 for summer and 26 for fall. A linear regression model was used to determine, for each event, the slope of the relationship between the DOC concentrations in the stream and Q. To contrast the antecedent conditions of the Hermine watershed, the events from a given season were divided into two groups. The Kruskal-Wallis test was then used to establish the link between the slope of the DOC/Q relationships on the one hand, and the environmental watershed conditions on the other hand: the climatic variables (volume of precipitation during event, mean air and soil temperatures) and the hydrological variables (stream discharge 24 h before the event, soil moisture, and ground water level).The DOC concentrations in the stream varied on an annual, a seasonal and an event basis. For the period 1994 to 2003, the annual mean concentrations, calculated from daily samples, varied from 2.0 to 2.5 mg DOC·L-1. On a seasonal basis, mean daily DOC was higher during the summer and the fall (2.9 and 2.8 mg DOC·L-1 respectively), and lower in the winter-spring (2.1 mg DOC·L-1). The relation between DOC concentrations and Q fluctuated as a function of the seasonal evolution of climatic and hydrological conditions in the Hermine catchment. For winter-spring events, 79% of the events had a DOC/Q slope lower than one. This period was characterised by high streamflow levels and high total DOC fluxes even though the daily mean DOC concentrations were low (2.1 mg DOC·L-1). The volume of precipitation during the event (p =0.041), the mean air temperature (p =0.001) and the soil temperature (p =0.009) were significantly related to the difference between events with slopes lower and higher than one. Indeed the slope of the relation increases when soil temperatures are elevated. When the temperatures are higher, DOC export increases and subsurface flow in soil horizon is enriched in DOC. Under colder temperature, the DOC production is limited and the soluble organic substances stored in soils are leached out the catchment with the high volume of precipitation and with the water coming from the snowmelt. For the summer period, there were 20 events with slopes greater than one against 14 with slopes lower than one. The soil humidity (p =0.039) and the total streamflow 24 h before the event (p=0.0003), were the two variables that significantly distinguished both slope groups. Rapid changes in DOC concentration occur during hydrological events following a long drought period. Under dry conditions, the subsurface flow in soil horizons rich in organic matter, the re-hydration of bed sediments and the hydrophobic behaviour of soil particles can all contribute to the export of very high DOC concentrations, even during small events. The relationships between DOC and Q, for the fall season, were significantly influenced by the volume of precipitation during the event (p =0.031) and the mean soil temperature (p =0.042). The events with the lower slopes showed the highest volume of precipitation during event and the lowest soil temperature. For these events occurring under wet conditions, the water originates essentially from the B and C horizons, and DOC fluctuations are then limited because of the low concentrations of the DOC in these horizons (anionic sorption of soluble organic substances by iron oxides).Best-fit from multiple regressions indicated that 40% of the link between DOC and Q was explained by the soil temperature during the winter-spring period (p =0.0001). For summer, the streamflow 24 h before events accounted for 51% of the variation in DOC/Q relationships (p =0.00001). For the fall period, the volume of precipitation during event and the soil temperature both contributed equally to the DOC/Q relationships (p =0.001). From these results, obtained from a multi-year project, it is clear that the relation between DOC and Q is a function of the variability in the climatic and hydrological watershed conditions. In a context of global warming, it is possible that warmer air temperatures have an effect on soil temperature. Thus, during winter-spring and fall periods, the duration and the intensity of the DOC production in soils will increase and the export of DOC from the watershed to other surface water system could become more important under equivalent or higher streamflow. Higher air temperature also means higher evapotranspiration by the forest during the summer period, and consequently dryer watershed conditions. A low streamflow and a low soil humidity level could be expected and then, brief rain events will sporadically flush the soluble organic carbon accumulated in the soil. The DOC export would be insignificant for that period, but the DOC would reach the highest annual level. The new knowledge on the DOC/Q relationships, at the hydrological event scale, will be added to the accumulated data on the possible effects of global warming on the carbon cycle in forested ecosystems

On the motion control of electric AGVS

The vehicle dynamic model -- Motion controller design -- A sliding mode motion controller -- An application example -- Simulation and test bench results

Stabilisation d'un tracteur-remorque : étude expérimentale de différents contrôleurs

Banc d'essais -- Modélisation et identification du système asservi -- Essais expérimentaux effectués avec l'algorithme BDL dans le cas d'un tracteur -- Comparaison avec les algorithmes d'Astolfi et de Roger Jang -- Essais expérimentaux effectués avec l'algorithme BDL dans le cas d'un tracteur-remorque -- Comparaison avec des versions étendues des algorithmes d'Astolfi et de Roger Jang

The QUEST large area CCD camera

We have designed, constructed, and put into operation a very large area CCD camera that covers the field of view of the 1.2 m Samuel Oschin Schmidt Telescope at the Palomar Observatory. The camera consists of 112 CCDs arranged in a mosaic of four rows with 28 CCDs each. The CCDs are 600 x 2400 pixel Sarnoff thinned, back-illuminated devices with 13 µm x 13 µm pixels. The camera covers an area of 4.6° x 3.6° on the sky with an active area of 9.6 deg_2. This camera has been installed at the prime focus of the telescope and commissioned, and scientific-quality observations on the Palomar-QUEST Variability Sky Survey were started in 2003 September. The design considerations, construction features, and performance parameters of this camera are described in this paper

Accounting for risk in valuing forest carbon offsets

<p>Abstract</p> <p>Background</p> <p>Forests can sequester carbon dioxide, thereby reducing atmospheric concentrations and slowing global warming. In the U.S., forest carbon stocks have increased as a result of regrowth following land abandonment and in-growth due to fire suppression, and they currently sequester approximately 10% of annual US emissions. This ecosystem service is recognized in greenhouse gas protocols and cap-and-trade mechanisms, yet forest carbon is valued equally regardless of forest type, an approach that fails to account for risk of carbon loss from disturbance.</p> <p>Results</p> <p>Here we show that incorporating wildfire risk reduces the value of forest carbon depending on the location and condition of the forest. There is a general trend of decreasing risk-scaled forest carbon value moving from the northern toward the southern continental U.S.</p> <p>Conclusion</p> <p>Because disturbance is a major ecological factor influencing long-term carbon storage and is often sensitive to human management, carbon trading mechanisms should account for the reduction in value associated with disturbance risk.</p

Real-world utilization and outcomes of systemic therapy among patients with advanced or recurrent endometrial cancer in the United States

OBJECTIVE: Evaluate systemic therapy utilization patterns and outcomes by line of therapy among patients with advanced/recurrent endometrial cancer (EC) treated in the United States. METHODS: This retrospective observational study used the Optum Clinformatics Extended Data Mart Date of Death database (1 January 2004-31 December 2019) and included de-identified data from adult patients with advanced/recurrent EC who were treated with first-line (1L) platinum-based chemotherapy and initiated second-line (2L) anti-neoplastic therapy. The index date was the date of 1L therapy initiation. The number and sequence of treatments received and the proportion of patients who received each type of treatment for each line of therapy were evaluated. To account for new drug approvals, patients first treated in 2018 or 2019 were also assessed separately. RESULTS: Among the 1317 patients who met all eligibility criteria, 520 (39.5%) and 235 (17.8%) patients received 3 or 4+ lines of treatment, respectively, during a median total follow-up time of 25.2 months (range, 2.5-173.3 months) following the index date. Chemotherapy, including platinum- and non-platinum-based regimens, was the most common treatment across all lines of therapy: 2L, 80.0%; 3L, 66.2%; 4L+, 80.4%. Overall, 2.5%, 2.3%, and 8.9% of 2L, 3L, and 4L + patients, respectively, received anti-program death 1 (anti-PD-1) immunotherapies. In patients first treated in 2018 and 2019 ( CONCLUSIONS: Among patients with advanced/recurrent EC treated with 1L platinum-based therapy in clinical practice, chemotherapy was the most common treatment choice across all lines of therapy. Immunotherapy use was low overall but increased in patients who started treatment in 2018 or 2019. Overall, median TTNT decreased as lines of therapy increased

E-Cadherin Expression Is Regulated by miR-192/215 by a Mechanism That Is Independent of the Profibrotic Effects of Transforming Growth Factor-β

OBJECTIVE--Increased deposition of extracellular matrix (ECM) within the kidney is driven by profibrotic mediators including transforming growth factor-[beta] (TGF-[beta]) and connective tissue growth factor (CTGF). We investigated whether some of their effects may be mediated through changes in expression of certain microRNAs (miRNAs). RESEARCH DESIGN AND METHODS--Proximal tubular cells, primary rat mesangial cells, and human podocytes were analyzed for changes in the expression of key genes, ECM proteins, and miRNA after exposure to TGF-[beta] (1-10 ng/[micro]l). Tubular cells were also infected with CTGF-adenovirus. Kidneys from diabetic apoE mice were also analyzed for changes in gene expression and miRNA levels. RESULTS--TGF-[beta] treatment was associated with morphologic and phenotypic changes typical of epithelial-mesenchymal transition (EMT) including increased fibrogenesis in all renal cell types and decreased E-cadherin expression in tubular cells. TGF-[beta] treatment also modulated the expression of certain miRNAs, including decreased expression of miR-192/215 in tubular cells, mesangial cells, which are also decreased in diabetic kidney. Ectopic expression of miR-192/215 increased E-cadherin levels via repressed translation of ZEB2 mRNA, in the presence and absence of TGF-[beta], as demonstrated by a ZEB2 3'-untranslated region luciferase reporter assay. However, ectopic expression of miR-192/215 did not affect the expression of matrix proteins or their induction by TGF-[beta]. In contrast, CTGF increased miR-192/215 levels, causing a decrease in ZEB2, and consequently increased E-cadherin mRNA. CONCLUSIONS--These data demonstrate the linking role of miRNA-192/215 and ZEB2 in TGF-[beta]/CTGF-mediated changes in E-cadherin expression. These changes appear to occur independently of augmentation of matrix protein synthesis, suggesting that a multistep EMT program is not necessary for fibrogenesis to occur.Bo Wang, Michal Herman-Edelstein, Philip Koh, Wendy Burns, Karin Jandeleit-Dahm, Anna Watson, Moin Saleem, Gregory J. Goodall, Stephen M. Twigg, Mark E. Cooper and Phillip Kantharidi

Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions

Background: Due to the chronic disease burden on society, there is a need for preventive public health interventions to stimulate society towards a healthier lifestyle. To deal with the complex variability between individual lifestyles and settings, collaborating with end-users to develop interventions tailored to their unique circumstances has been suggested as a potential way to improve effectiveness and adherence. Co-creation of public health interventions using participatory methodologies has shown promise but lacks a framework to make this process systematic. The aim of this paper was to identify and set key principles and recommendations for systematically applying participatory methodologies to co-create and evaluate public health interventions. Methods: These principles and recommendations were derived using an iterative reflection process, combining key learning from published literature in addition to critical reflection on three case studies conducted by research groups in three European institutions, all of whom have expertise in co-creating public health interventions using different participatory methodologies. Results: Key principles and recommendations for using participatory methodologies in public health intervention co-creation are presented for the stages of: Planning (framing the aim of the study and identifying the appropriate sampling strategy); Conducting (defining the procedure, in addition to manifesting ownership); Evaluating (the process and the effectiveness) and Reporting (providing guidelines to report the findings). Three scaling models are proposed to demonstrate how to scale locally developed interventions to a population level. Conclusions: These recommendations aim to facilitate public health intervention co-creation and evaluation utilising participatory methodologies by ensuring the process is systematic and reproducible

Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of $^{238}$U$_{e}$~$<$1.6~mBq/kg, $^{238}$U$_{l}$~$<$0.09~mBq/kg, $^{232}$Th$_{e}$~$=0.28\pm 0.03$~mBq/kg, $^{232}$Th$_{l}$~$=0.25\pm 0.02$~mBq/kg, $^{40}$K~$<$0.54~mBq/kg, and $^{60}$Co~$<$0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of $0.160\pm0.001$(stat)$\pm0.030$(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle Physic