181 research outputs found

    Application of the Analysis Time Series and Multispectral Images for the Estimation of the Conditions of the Vegetation Covers of the Natural Areas of Southern Spain

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    It has been scientifically proven that climate change is a reality. In subarid Mediterranean limates, this fact is observed in the irregular distribution of rainfall, resulting in alternating periods of more or less prolonged drought with episodes of torrential rains concentrated in short periods of time. We have selected 11 natural areas in southern Spain, where we will observe these circumstances and where a series of ecosystems composed of vegetation covers of a high ecological value are found. We start from the question of whether these climatic circumstances are really deteriorating them. For this study, we propose a method that combines three analysis techniques: the design of the time series, the application of vegetation indices, and the use of techniques analysis of changes in land use. From the combination of these techniques in the period from 1997 to 2021, we have observed that there have been a dynamic of changes in land use that has maintained its original characteristics by more than 70%, so it is possible to affirm that the adaptation of ecosystems to climatic conditions has occurred satisfactorily. However, this general statement shows some particularities which are those that we will show in this work.This research is part of the project: Effects of Land Use Changes on Eco-Geomorphological Dynamics in Mediterranean Environments, At Different Scales, In the Context of Global Change. Funding number: PID2019-104046RB-I00. Was funded by the MINECO (Ministry of Economic Affairs and Digital Transformation) and 2019 Call for “I + D + I Projects” within the Framework of State Programs for the Generation of Knowledge and Scientific and Technological Strengthening of the I + D + I System and I + D + I oriented to the Challenges of Society. And partial funding for open access charge: University of Málaga and Consortium of University Libraries of Andalusia (CBUA acronym in Spain)

    Potential strong contribution of future anthropogenic land-use and land-cover change to the terrestrial carbon cycle

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    Anthropogenic land-use and land cover changes (LULCC) affect global climate and global terrestrial carbon (C) cycle. However, relatively few studies have quantified the impacts of future LULCC on terrestrial carbon cycle. Here, using Earth system model simulations performed with and without future LULCC, under the RCP8.5 scenario, we find that in response to future LULCC, the carbon cycle is substantially weakened: browning, lower ecosystem C stocks, higher C loss by disturbances and higher C turnover rates are simulated. Projected global greening and land C storage are dampened, in all models, by 22% and 24% on average and projected C loss by disturbances enhanced by ~49% when LULCC are taken into account. By contrast, global net primary productivity is found to be only slightly affected by LULCC (robust +4% relative enhancement compared to all forcings, on average). LULCC is projected to be a predominant driver of future C changes in regions like South America and the southern part of Africa. LULCC even cause some regional reversals of projected increased C sinks and greening, particularly at the edges of the Amazon and African rainforests. Finally, in most carbon cycle responses, direct removal of C dominates over the indirect CO2 fertilization due to LULCC. In consequence, projections of land C sequestration potential and Earth\u27s greening could be substantially overestimated just because of not fully accounting for LULCC

    Potential strong contribution of future anthropogenic land-use and land-cover change to the terrestrial carbon cycle

    Get PDF
    Anthropogenic land-use and land cover changes (LULCC) affect global climate and global terrestrial carbon (C) cycle. However, relatively few studies have quantified the impacts of future LULCC on terrestrial carbon cycle. Here, using Earth system model simulations performed with and without future LULCC, under the RCP8.5 scenario, we find that in response to future LULCC, the carbon cycle is substantially weakened: browning, lower ecosystem C stocks, higher C loss by disturbances and higher C turnover rates are simulated. Projected global greening and land C storage are dampened, in all models, by 22% and 24% on average and projected C loss by disturbances enhanced by ~49% when LULCC are taken into account. By contrast, global net primary productivity is found to be only slightly affected by LULCC (robust +4% relative enhancement compared to all forcings, on average). LULCC is projected to be a predominant driver of future C changes in regions like South America and the southern part of Africa. LULCC even cause some regional reversals of projected increased C sinks and greening, particularly at the edges of the Amazon and African rainforests. Finally, in most carbon cycle responses, direct removal of C dominates over the indirect CO2 fertilization due to LULCC. In consequence, projections of land C sequestration potential and Earth\u27s greening could be substantially overestimated just because of not fully accounting for LULCC

    Prevalencija molarno-incizivne hipomineralizacije u skupini panjolske kolske djece

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    Svrha rada: Molarno-incizivna hipomineralizacija (MIH) poremećaj je u razvoju zuba koji zahvaća prve trajne kutnjake i trajne sjekutiće. Prevalencija MIH-a u literaturi varira između 2,5 i 40 posto svjetske dječje populacije. Malo je informacija o pojavnosti toga poremećaja među djecom u panjolskoj. Svrha rada bila je ispitati njegovu učestalost među kolskom djecom iz Barcelone ( panjolska). Materijali i metode: Provedeno je istra ivanje poprečnog presjeka koje je uključivalo 705 djece u dobi od 6 do 14 godina i 11 mjeseci. Svi su klinički pregledani u skladu s kriterijima Europske akademije za dječju stomatologiju za dijagnozu MIH-a. Rezultati: Pronađeno je ukupno 56 slučajeva MIH-a - 22 (39,3 %) kod dječaka i 34 (60,7 %) kod djevojčica. Prevalencija je iznosila 7,94 posto (6,39 % za dječake i 9,41 % za djevojčice). Lezije MIH-a če će su zabilje ene kod djevojčica negoli kod dječaka (c2 = 4,9, p = 0,023) - omjer mu kih/ enskih osoba iznosi 1:1,54. U oba spola gornji zubi bili su če će zahvaćeni negoli donji, s omjerom gornji/donji od 1,86/1 za dječake i 1,68/1 za djevojčice. Zaključak: S obzirom na spol i zahvaćene zube, če će su bili pogođeni gornji zubi i djevojčice

    Experimental resuts and simulation with TRNSYS of a 7.2 kWp grid-connected photovoltaic system

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    This paper presents a dynamic model and experimental results of a 7.2. kWp photovoltaic (PV) installation located at the Polytechnic University of Valencia (Spain). The modelling of the monocrystalline cells has been realised in TRNSYS and has been validated during an extensive experimental campaign from January 2001 to March 2003, using the data of a fully monitored PV field. The simulation results with TRNSYS provide an accurate prediction of the long-term performance. In addition to the dynamic models, algebraic methods such as the constant fill factor have also been applied.In the design of PV systems, there are several important uncertainties which have to be taken into account, such as the reduction of power with respect to the nominal power under Standard Test Conditions (STC), the choice of the meteorological database, and the models for the calculation of the radiation on tilted surface and of the cell temperature. These aspects are analyzed thoroughly in this paper, as well as the problems inherent to the PV power injection into the grid.Quesada, BR.; Sánchez, C.; Cañada, J.; Royo Pastor, R.; J. Payá (2011). Experimental resuts and simulation with TRNSYS of a 7.2 kWp grid-connected photovoltaic system. Applied Energy. 88:1772-1783. doi:10.1016/j.apenergy.2010.12.011S177217838

    Land-surface characteristics and climate in West Africa : Models’ biases and impacts of historical anthropogenically-induced deforestation

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    Land Use Land-Cover Change (LULCC), such as deforestation, affects the climate system and land-atmosphere interactions. Using simulations carried out within the LUCID (Land Use and Climate, IDentification of robust Impacts) project framework, we first quantify the role of historical land-cover change induced by human activities on surface climate in West Africa. Focusing on two contrasted African regions, we find that climate responses of land-use changes are small but they are still statistically significant. In Western Sahel, a statistically significant near-surface atmospheric cooling and a decrease in water recycling are simulated in summer in response to LULCC. Over the Guinean zone, models simulate a significant decrease in precipitation and water recycling in autumn in response to LULCC. This signal is comparable in magnitude with the effect induced by the increase in greenhouse gases. Simulated climate changes due to historical LULCC could however be underestimated because: (i) the prescribed LULCC can be underestimated in those regions; (ii) the climate models underestimate the coupling strength between West African surface climate and leaf area index (LAI) and (iii) the lack of interactive LAI in some models. Finally, our study reveals indirect atmospheric processes triggered by LULCC. Over the Western Sahel, models reveal that a significant decrease in solar reflection tend to cool down the surface and thus counteract the atmospheric feedback. Conversely, over the Guinea zone, models reveal that the indirect atmospheric processes and turbulent heat fluxes dominate the climatic responses over the direct effects of LULCC

    Understanding the uncertainty in global forest carbon turnover

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    The length of time that carbon remains in forest biomass is one of the largest uncertainties in the global carbon cycle, with both recent historical baselines and future responses to environmental change poorly constrained by available observations. In the absence of large-scale observations, models used for global assessments tend to fall back on simplified assumptions of the turnover rates of biomass and soil carbon pools. In this study, the biomass carbon turnover times calculated by an ensemble of contemporary terrestrial biosphere models (TBMs) are analysed to assess their current capability to accurately estimate biomass carbon turnover times in forests and how these times are anticipated to change in the future. Modelled baseline 1985-2014 global average forest biomass turnover times vary from 12.2 to 23.5 years between TBMs. TBM differences in phenological processes, which control allocation to, and turnover rate of, leaves and fine roots, are as important as tree mortality with regard to explaining the variation in total turnover among TBMs. The different governing mechanisms exhibited by each TBM result in a wide range of plausible turnover time projections for the end of the century. Based on these simulations, it is not possible to draw robust conclusions regarding likely future changes in turnover time, and thus biomass change, for different regions. Both spatial and temporal uncertainty in turnover time are strongly linked to model assumptions concerning plant functional type distributions and their controls. Thirteen model-based hypotheses of controls on turnover time are identified, along with recommendations for pragmatic steps to test them using existing and novel observations. Efforts to resolve uncertainty in turnover time, and thus its impacts on the future evolution of biomass carbon stocks across the world\u27s forests, will need to address both mortality and establishment components of forest demography, as well as allocation of carbon to woody versus non-woody biomass growth

    Evolution of CRISPR-associated endonucleases as inferred from resurrected proteins

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    Clustered regularly interspaced short palindromic repeats (CRISPR)-associated Cas9 is an effector protein that targets invading DNA and plays a major role in the prokaryotic adaptive immune system. Although Streptococcus pyogenes CRISPR–Cas9 has been widely studied and repurposed for applications including genome editing, its origin and evolution are poorly understood. Here, we investigate the evolution of Cas9 from resurrected ancient nucleases (anCas) in extinct firmicutes species that last lived 2.6 billion years before the present. We demonstrate that these ancient forms were much more flexible in their guide RNA and protospacer-adjacent motif requirements compared with modern-day Cas9 enzymes. Furthermore, anCas portrays a gradual palaeoenzymatic adaptation from nickase to double-strand break activity, exhibits high levels of activity with both single-stranded DNA and single-stranded RNA targets and is capable of editing activity in human cells. Prediction and characterization of anCas with a resurrected protein approach uncovers an evolutionary trajectory leading to functionally flexible ancient enzymes.This work has been supported by grant nos. PID2019-109087RB-I00 (to R.P.-J.) and RTI2018-101223-B-I00 and PID2021-127644OB-I00 (to L.M.) from the Spanish Ministry of Science and Innovation. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 964764 (to R.P.-J.). The content presented in this document represents the views of the authors, and the European Commission has no liability in respect to the content. We acknowledge financial support from the Spanish Foundation for the Promotion of Research of Amyotrophic Lateral Sclerosis. A.F. acknowledges Spanish Center for Biomedical Network Research on Rare Diseases (CIBERE) intramural funds (no. ER19P5AC756/2021). F.J.M.M. acknowledges research support by Conselleria d’Educació, Investigació, Cultura i Esport from Generalitat Valenciana, research project nos. PROMETEO/2017/129 and PROMETEO/2021/057. M.M. acknowledges funding from CIBERER (grant no. ER19P5AC728/2021). The work has received funding from the Regional Government of Madrid (grant no. B2017/BMD3721 to M.A.M.-P.) and from Instituto de Salud Carlos III, cofounded with the European Regional Development Fund ‘A way to make Europe’ within the National Plans for Scientific and Technical Research and Innovation 2017–2020 and 2021–2024 (nos. PI17/1659, PI20/0429 and IMP/00009; to M.A.M.-P. B.P.K. was supported by an MGH ECOR Howard M. Goodman Award and NIH P01 HL142494

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
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