Modelling above-ground carbon dynamics using multi-temporal airborne lidar: Insights from a Mediterranean woodland

Abstract. Woodlands represent highly significant carbon sinks globally, though could lose this function under future climatic change. Effective large-scale monitoring of these woodlands has a critical role to play in mitigating for, and adapting to, climate change. Mediterranean woodlands have low carbon densities, but represent important global carbon stocks due to their extensiveness and are particularly vulnerable because the region is predicted to become much hotter and drier over the coming century. Airborne lidar is already recognized as an excellent approach for high-fidelity carbon mapping, but few studies have used multi-temporal lidar surveys to measure carbon fluxes in forests and none have worked with Mediterranean woodlands. We use a multi-temporal (5-year interval) airborne lidar data set for a region of central Spain to estimate above-ground biomass (AGB) and carbon dynamics in typical mixed broadleaved and/or coniferous Mediterranean woodlands. Field calibration of the lidar data enabled the generation of grid-based maps of AGB for 2006 and 2011, and the resulting AGB change was estimated. There was a close agreement between the lidar-based AGB growth estimate (1.22 Mg ha−1 yr−1) and those derived from two independent sources: the Spanish National Forest Inventory, and a tree-ring based analysis (1.19 and 1.13 Mg ha−1 yr−1, respectively). We parameterised a simple simulator of forest dynamics using the lidar carbon flux measurements, and used it to explore four scenarios of fire occurrence. Under undisturbed conditions (no fire) an accelerating accumulation of biomass and carbon is evident over the next 100 years with an average carbon sequestration rate of 1.95 Mg C ha−1 yr−1. This rate reduces by almost a third when fire probability is increased to 0.01 (fire return rate of 100 years), as has been predicted under climate change. Our work shows the power of multi-temporal lidar surveying to map woodland carbon fluxes and provide parameters for carbon dynamics models. Space deployment of lidar instruments in the near future could open the way for rolling out wide-scale forest carbon stock monitoring to inform management and governance responses to future environmental change.The authors would like to acknowledge the personnel of the Airborne Research and Survey Facility (NERC). We thank the MAGRAMA for granting access to the Spanish Forest Inventory. WS was funded by FunDivEurope and the Isaac Newton Trust. PRB was supported by The International Post doc Fellowship Programme in Plant Sciences (PLANT FELLOWS).This is the final version of the article. It first appeared from Copernicus via http://dx.doi.org/10.5194/bg-13-961-201

Nanociència : l'important no rau en la noblesa

La nanociència avança dia a dia en el que és el seu camp amb més projecció: les nanopartícules metàl·liques (NPMs). Les excepcionals propietats físico-químiques que les caracteritzen fan possible les seves aplicacions electroquímiques. Aquestes però, poden veure's afectades degut a la tendència de les NPMs a agregar-se, perdent així, la seva forma original. Estabilitzant-les en matrius polimèriques, no només s'ha aconseguit controlar les seves mides i velocitat de creixement, sinó que també poden ser emmagatzemades en forma sòlida i líquida, gràcies a la solubilitat dels polímers. Aquestes aplicacions electroquímiques, tal i com s'explica en el següent article, es basen en l'ús de metalls nobles (partícules monometàl·liques), la qual cosa encareix molt el procés. D'aquí que un dels objectius sigui decréixer la quantitat d'aquests metalls -sense perdre la seva capacitat electrocatalítica- i preparar nanopartícules del tipus nucli-embolcall (bimetàl·liques). Aquestes posseeixen un nucli de metall econòmic recobert per un altre de noble, i han demostrat ser més estables en quant a mida i forma, a més de presentar una activitat electrocatalítica superior.La nanociencia avanza día a día en el que es su campo con más proyección: las nanopartículas metálicas (NPMs). Las excepcionales propiedades físico-químicas que las caracterizan hacen posible sus aplicaciones electroquímicas. Éstas, sin embargo, pueden verse afectadas debido a la tendencia de las NPMs a agregarse, perdiendo, así, su forma original. Estabilizándolas en matrices poliméricas, no sólo se ha conseguido controlar su tamaño y velocidad de crecimiento, sino que también pueden ser almacenadas en forma sólida y líquida, gracias a la solubilidad de los polímeros. Estas aplicaciones electroquímicas, tal como se explica en el siguiente artículo, se basan en el uso de metales nobles (partículas monometálicas), lo que encarece mucho el proceso. De aquí que uno de los objetivos sea disminuir la cantidad de estos metales -sin perder su capacidad electrocatalítica- y preparar nanopartículas del tipo núcleo-envoltorio (bimetálicas). Éstas poseen un núcleo de metal económico recubierto por otro que es noble, y han demostrado ser más estables en cuanto a tamaño y forma, además de presentar una actividad electrocatalítica superior, siempre y cuando se mantenga la misma cantidad de metal noble.The field of metallic nanoparticles (MNP), one of the nanoscience fields with most projection, advances daily. The exceptional characteristic physical and chemical properties of these particles make it possible to use them in electrochemical applications. However, this can be affected by the tendency of MNPs to group together and thus lose their original form. By stabilising the particles in polymeric matrices it is possible not only to control their size and speed of growth, but to store them in solid and liquid forms due to the solubility of polymers. As explained in the following article, noble metals (monometallic particles) are used in electrochemical applications, which make the process extremely expensive. The objective therefore is to reduce the quantity of noble metal used -without compromising electrocatalytic capacity -and add core-shell (bimetallic) nanoparticles. These possess a more economical metal core covered by a noble metal shell. They have been proved to be more stable in both size and shape, and display greater electrocatalytic activity

Efectos del clima y la estructura del rodal sobre procesos de mortalidad en los bosques ibéricos.

Herrero A & Zavala MA, editores (2015) Los Bosques y la Biodiversidad frente al Cambio Climático: Impactos, Vulnerabilidad y Adaptación en España. Ministerio de Agricultura, Alimentación y Medio Ambiente, Madrid.Peer Reviewe

Altered DNA methylation in human placenta after (suspected) preterm labor

Aim: The aim of this study was to determine if alterations in DNA methylation in the human placenta would support suspected preterm labor as a pathologic insult associated with diminished placental health. Methods: We evaluated placental DNA methylation at seven loci differentially methylated in placental pathologies using targeted bisulfite sequencing, in placentas associated with preterm labor (term birth after suspected preterm labor [n = 15] and preterm birth [n = 15]), and controls (n = 15). Results: DNA methylation levels at the NCAM1 and PLAGL1 loci in placentas associated with preterm labor did differ significantly (p < 0.05) from controls. Discussion: Specific alterations in methylation patterns indicative of an unfavourable placental environment are associated with preterm labor per se and not restricted to preterm birth

Calculation of the interventilatory threshold area: a method for examining the aerobic-anaerobic transition

El objetivo fue determinar la relación entre el área interumbrales (ITA) [la zona comprendida entre el primer y el segundo umbral ventilatorio (VT1 y VT2) en la función VO2/VE, Carga/VO2 y Carga/VE] y las variables ergoespirométricas. Treinta y tres hombres realizaron un test incremental. El ITA se calculó: 1) como la integral definida por el área entre VT1 y VT2 bajo las curvas de VO2/VE, Carga/VO2 y Carga/VE y 2) como la suma de las áreas descritas por el triángulo y rectángulo entre los mismos puntos. El ITA para la función Carga/VE se correlacionó positivamente (p<0,01) con la carga en VT2 (r = 0,831) y la ventilación en VT2 (r = 0,799). El ITA para la función VO2/VE fue significativamente mayor en los ciclistas que en los estudiantes. La determinación del ITA es un método simple para evaluar la transición aeróbica-anaeróbica durante las pruebas de esfuerzo incremental.The aim was to determine the relationship between the interthreshold area (ITA) [the area between the first and second ventilatory threshold (VT1 and VT2) for the function VO2/VE, load/VO2 and load/VE] and the traditional variables measured. Thirty-three men underwent an incremental test. The ITA was calculated: 1) as the integral defined by the area between VT1 and VT2 under the curves for the functions VO2/VE, load/VO2 and load/VE and 2) as the simple sum of the areas described by the triangle and rectangle between the same points. The mean ITA for the function load/VE was positively correlated (p<0.01) with load at VT2 (r=0.831) and ventilation at VT2 (r=0.799). The mean ITA for the function VO2/VE was significantly greater in the cyclists than in the students. The ITA for the function load/VE differed between March and July as training progressed. The determination of the ITA is a simple method of assessing the aerobic-anaerobic transition process during incremental exercise tests

SARS-CoV-2 congenital infection and pre-eclampsia-like syndrome in dichorionic twins: A case report and review of the literature

Although the route of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mainly respiratory, vertical transmission seems possible.1 We report the case of a woman with a dichorionic diamniotic twin pregnancy admitted to Hospital Clínico Universitario Lozano Blesa at 38+4 weeks of gestation due to severe pre-eclampsia in the context of a SARS-CoV-2 infection (positive nasopharyngeal PCR; Viasure, CerTest Biotec., Zaragoza, Spain) with a probable transplacental transmission of the virus to both twins..

Multiple abiotic and biotic pathways shape biomass demographic processes in temperate forests

International audienceForests play a key role in regulating the global carbon cycle, and yet the abiotic and biotic conditions that drive the demographic processes that underpin forest carbon dynamics remain poorly understood in natural ecosystems. To address this knowledge gap, we used repeat forest inventory data from 92,285 trees across four large permanent plots (4-25 ha in size) in temperate mixed forests in northeast China to ask the following questions: (1) How do soil conditions and stand age drive biomass demographic processes? (2) How do vegetation quality (i.e., functional trait diversity and composition) and quantity (i.e., initial biomass stocks) influence biomass demographic processes independently from soil conditions and stand age? (3) What is the relative contribution of growth, recruitment, and mortality to net biomass change? Using structural equation modeling, we showed that all three demographic processes were jointly constrained by multiple abiotic and biotic factors and that mortality was the strongest determinant on net biomass change over time. Growth and mortality, as well as functional trait diversity and the community-weighted mean of specific leaf area (CWM SLA), declined with stand age. By contrast, high soil phosphorous concentrations were associated with greater functional diversity and faster dynamics (i.e., high growth and mortality rates), but associated with lower CWM SLA and initial biomass stock. More functionally diverse communities also had higher recruitment rates, but did not exhibit faster growth and mortality. Instead, initial biomass stocks and CWM SLA were stronger predictors of biomass growth and mortality, respectively. By integrating the full spectrum of abiotic and biotic drivers of forest biomass dynamics, our study provides critical system-level insights needed to predict the possible consequences of regional changes in forest diversity, composition, structure and function in the context of global change

SARS-CoV-2 immunochromatographic IgM/IgG rapid test in pregnancy: A false friend?

Background: An increasing body of evidence has revealed that SARS-CoV-2 infection in pregnant women could increase the risk of adverse maternal and fetal outcomes. Careful monitoring of pregnancies with COVID-19 and measures to prevent neonatal infection are warranted. Therefore, rapid antibody tests have been suggested as an efficient screening tool during pregnancy. Cases: We analysed the clinical performance during pregnancy of a rapid, lateral-flow immunochromatographic assay for qualitative detection of SARS-CoV-2 IgG/IgM antibodies. We performed a universal screening including 169 patients during their last trimester of pregnancy. We present a series of 14 patients with positive SARS-CoV-2 immunochromatographic assay rapid test result. Immunochromatographic assay results were always confirmed by chemiluminescent microparticle immunoassays for quantitative detection of SARS-CoV-2 IgG and IgM+IgA antibodies as the gold standard. We observed a positive predictive value of 50% and a false positive rate of 50% in pregnant women, involving a significantly lower diagnostic performance than reported in non-pregnant patients. Discussion: Our data suggest that although immunochromatographic assay rapid tests may be a fast and profitable screening tool for SARS-CoV-2 infection, they may have a high false positive rate and low positive predictive value in pregnant women. Therefore, immunochromatographic assay for qualitative detection of SARS-CoV-2 IgG/IgM antibodies must be verified by other test in pregnant patients