528 research outputs found

    Forty Years of Wildland Urban Interface Growth and Its Relation With Wildfires in Central-Western Chubut, Argentina

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    Wildland Urban Interface (WUI) areas are rapidly expanding worldwide. In many regions of the world, this expansion could be explained by the increasing possibilities of telecommuting and developing home-office work, while at the same time living in, or surrounded by wilderness areas of magnificent beauty. However, growth and development of these WUIs are still not well dimensioned and regulated, especially in fire prone ecosystems. Over the last two decades, an increasingly number of megafires occurred in these WUI areas in different regions of the world. Recently, big megafires occurred in WUIs located around towns in the western Andean-Patagonian region of Argentina. In this study, we analyzed the evolution of the WUI and its relationship with wildfires around cities and towns located in the northwestern part of Chubut province of Argentina. The studied region covers 324,823 ha and includes the cities of Esquel and Trevelin, and other small villages. Our objectives were to (i) map the current WUI, (ii) quantify changes occurred in the WUI in the last 40 years around the main cities of the region, and (iii) analyze the relationships among WUIs, vegetation types, and wildfire occurrence. We mapped the distribution of WUI using spatially explicit information on housing density derived from censuses and high-resolution imagery from 1981/1982 and 2021, and land cover data. The current WUI covered 8% of the study area, however it has 97% of the houses. Between 1981 and 2021, the WUI area increased by 80%, especially in the southern part of our study region. Finally, information on wildfires distribution revealed that 65% of the ignition points of the recent fires in the region occurred within the WUI. Most of the vegetation burned were herbs, sub-shrubs and woodlands. WUI expansion in our study area appears to be constrained by terrain features (slopes and accessibility), but not by vegetation characteristics. Our study suggests that continuing, unplanned housing expansion in wilderness areas without appropriate vegetation management will likely increases wildfire risk and human environmental conflicts further. Effective land use planning and wildfire management are crucial for sustainable housing expansion in western Patagonia.Fil: Godoy, Maria Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Martinuzzi, Sebastián. University of Wisconsin; Estados UnidosFil: Masera, Pablo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Defossé, Guillermo Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentin

    “Redes y Universidades Emprendedoras. El Desafío de la Participación”

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    La universidad, inmersa en un contexto de cambios, debe replantear su organización y los valores que promueve, para hacer frente a una serie de desafíos, entre ellos: 1- La mundialización y los nuevos modelos de ciencia, orientados hacia la producción científico-tecnológica (investigación colaborativa precompetitiva); 2- La necesidad de establecer relaciones más efectivas entre ciencia, tecnología, sociedad y producción. Se sostiene que la universidad emprendedora, a partir de la acción de sus propiedades culturales y organizacionales, es la institución que está capacitada para trabajar en red. Las redes son una defensa frente a los corolarios de la mundialización, dado que permiten no sólo la transferencia de tecnología, sino en un nivel cualitativamente superior, la cooperación de grupos de individuos e instituciones con objetivos comunes. Las redes, además, son herramientas aptas para la modernización de las universidades. Se concluye que las redes, con la participación de universidades emprendedoras, son un mecanismo eficaz para promover la articulación entre la academia y empresas, gobiernos, y centros de I+D

    Mecanismos de resistencia en Nothofagus dombeyi ante agentes estresores bióticos y abióticos en un contexto de Cambio Climático

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    El Coihue (Nothofagus dombeyi) es una de las especies que más destacan en los bosques andino patagónicos, principalmente en los Parques Nacionales Nahuel Huapi y Los Alerces, donde constituyen un importante recurso turístico turístico, económico, y de biodiversidad. En los últimos años, el Coihue ha demostrado sensibilidad a eventos de sequías intensas, presentando decaimiento y mortalidad. En el marco del proyecto “Sanidad de los Bosques Andino Patagónicos: Etiología de Enfermedades y Mecanismos de Resistencia de Especies Emblemáticas” (PICT 2015-1933) del CIEFAP, dirigido por el Dr. Mario Rajchenberg, se busca comprender mejor los procesos que intervienen en el decaimiento y la mortalidad de los bosques de Coihue en relación a las sequías. Particularmente se busca determinar para la especie, los mecanismos asociados a la sensibilidad ante agentes estresores, tanto bióticos como abióticos.Fil: Masera, Pablo Alberto. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Científica y Tecnológica; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Pildain, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Dalla Salda, Guillermina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Rajchenberg, Mario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: de Errasti, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Sargent, Anne Sophie. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Urretavizcaya, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentin

    Production of Λ\Lambda and KS0{\rm K}^{0}_{\rm S} in jets in p-Pb collisions at sNN=5\sqrt{s_{\rm NN}} = 5 TeV and pp collisions at s=7\sqrt{s} = 7 TeV

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    The production of Λ\Lambda baryons and KS0{\rm K}^{0}_{\rm S} mesons (V0{\rm V}^{0} particles) was measured in p-Pb collisions at sNN=5\sqrt{s_{\rm NN}} = 5 TeV and pp collisions at s=7\sqrt{s} = 7 TeV with ALICE at the LHC. The production of these strange particles is studied separately for particles associated with hard scatterings and the underlying event to shed light on the baryon-to-meson ratio enhancement observed at intermediate transverse momentum (pTp_{\rm T}) in high multiplicity pp and p-Pb collisions. Hard scatterings are selected on an event-by-event basis with jets reconstructed with the anti-kTk_{\rm T} algorithm using charged particles. The production of strange particles associated with jets pT,  jetch>10p_{\rm T,\;jet}^{\rm ch}>10 GeV/cc is reported as a function of pTp_{\rm T} in both systems; and its dependence on pTp_{\rm T} with jets pT,  jetch>20p_{\rm T,\;jet}^{\rm ch}>20 GeV/cc and on angular distance from the jet axis, R(V0,  jet)R({\rm V}^{0},\;{\rm jet}), for jets with pT,  jetch>10p_{\rm T,\;jet}^{\rm ch} > 10 GeV/cc are reported in p-Pb collisions. The results are compared with the strange particle production in the underlying event. The Λ/KS0\Lambda/{\rm K}^{0}_{\rm S} ratio associated with jets in p-Pb collisions for R(V0,  jet)<0.4R({\rm V}^{0},\;{\rm jet})<0.4 is consistent with the ratio measured in pp collisions and with the expectation of jets fragmenting in vacuum given by the PYTHIA event generator

    Λc+\Lambda^+_c production in pppp and in pp-Pb collisions at sNN\sqrt {s_{NN}}=5.02 TeV

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    International audienceThe production cross section of prompt Λc+\mathrm{\Lambda_{c}^{+}} charm baryons was measured with the ALICE detector at the LHC at midrapidity in proton-proton (pp) and proton-lead (p-Pb) collisions at a centre-of-mass energy per nucleon pair of sNN=5.02\sqrt{s_\mathrm{NN}} = 5.02 TeV. The Λc+\mathrm{\Lambda_{c}^{+}} and Λc\rm {\overline{\Lambda}{}_c^-} baryons were reconstructed in the hadronic decay channels Λc+pKπ+\rm \Lambda_{c}^{+} \rightarrow p K^{-}\pi^{+} and Λc+pKS0\rm \Lambda_{c}^{+}\to p K^{0}_{S} and respective charge conjugates. The measured differential cross sections as a function of transverse momentum (pTp_{\rm T}) and the pTp_{\rm T}-integrated Λc+\mathrm{\Lambda_{c}^{+}} production cross section in pp and in p-Pb collisions are presented. The Λc+\mathrm{\Lambda_{c}^{+}} nuclear modification factor (RpPbR_\mathrm{pPb}), calculated from the cross sections in pp and in p-Pb collisions, is presented and compared with the RpPbR_\mathrm{pPb} of D mesons. The Λc+/D0\mathrm {\Lambda_{c}^{+}}/\mathrm {D^0} ratio is also presented and compared with the light-flavour baryon-to-meson ratios p/π/\pi and Λ/KS0\Lambda /\mathrm {K^0_S}, and measurements from other LHC experiments. The results are compared to predictions from model calculations and Monte Carlo event generators

    Measurement of Prompt D0^{0}, Λc+\Lambda_{c}^{+}, and Σc0,++\Sigma_{c}^{0,++}(2455) Production in Proton–Proton Collisions at s\sqrt s = 13  TeV

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    International audienceThe pT-differential production cross sections of prompt D0, Λc+, and Σc0,++(2455) charmed hadrons are measured at midrapidity (|y|&lt;0.5) in pp collisions at s=13  TeV. This is the first measurement of Σc0,++ production in hadronic collisions. Assuming the same production yield for the three Σc0,+,++ isospin states, the baryon-to-meson cross section ratios Σc0,+,++/D0 and Λc+/D0 are calculated in the transverse momentum (pT) intervals 2&lt;pT&lt;12 and 1&lt;pT&lt;24  GeV/c. Values significantly larger than in e+e- collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the Σc. The feed-down contribution to Λc+ production from Σc0,+,++ is also reported and is found to be larger than in e+e- collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronization mechanisms implemented in the models

    Measurements of mixed harmonic cumulants in Pb–Pb collisions at sNN\sqrt {s_{NN}} = 5.02 TeV

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    Correlations between moments of different flow coefficients are measured in Pb–Pb collisions at sNN\sqrt {s_{NN}} = 5.02 TeV recorded with the ALICE detector. These new measurements are based on multiparticle mixed harmonic cumulants calculated using charged particles in the pseudorapidity region |η|<0.8 with the transverse momentum range 0.2 < pTp_T < 5.0 GeV/c . The centrality dependence of correlations between two flow coefficients as well as the correlations between three flow coefficients, both in terms of their second moments, are shown. In addition, a collection of mixed harmonic cumulants involving higher moments of v2v_2 and v3v_3 is measured for the first time, where the characteristic signature of negative, positive and negative signs of four-, six- and eight-particle cumulants are observed, respectively. The measurements are compared to the hydrodynamic calculations using iEBE-VISHNU with AMPT and TRENTo initial conditions. It is shown that the measurements carried out using the LHC Run 2 data in 2015 have the precision to explore the details of initial-state fluctuations and probe the nonlinear hydrodynamic response of v2v_2 and v3v_3 to their corresponding initial anisotropy coefficients ε2ε_2 and ε3ε_3 . These new studies on correlations between three flow coefficients as well as correlations between higher moments of two different flow coefficients will pave the way to tighten constraints on initial-state models and help to extract precise information on the dynamic evolution of the hot and dense matter created in heavy-ion collisions at the LHC

    Inclusive J/ψ\psi production at midrapidity in pp collisions at s = 13\sqrt{s}~=~13 TeV

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    We report on the inclusive J/ψ\psi production cross section measured at the CERN Large Hadron Collider in proton-proton collisions at a centre-of-mass energy s = 13\sqrt{s}~=~13 TeV. The J/ψ\psi mesons are reconstructed in the e+e\rm e^{+} e^{-} decay channel and the measurements are performed at midrapidity (y<0.9|y|<0.9) in the transverse-momentum interval 0<pT<400< p_{\rm T} <40 GeV/cc, using a minimum bias data sample corresponding to an integrated luminosity Lint=32.2 nb1L_{\text{int}} = 32.2~\text{nb}^{-1} and an Electromagnetic Calorimeter triggered data sample with Lint=8.3 pb1L_{\text{int}} = 8.3~\mathrm{pb}^{-1}. The pTp_{\rm T}-integrated J/ψ\psi production cross section at midrapidity, computed using the minimum bias data sample, is dσ/dyy=0=8.97±0.24 (stat)±0.48 (syst)±0.15 (lumi) μb\text{d}\sigma/\text{d}y|_{y=0} = 8.97\pm0.24~(\text{stat})\pm0.48~(\text{syst})\pm0.15~(\text{lumi})~\mu\text{b}. An approximate logarithmic dependence with the collision energy is suggested by these results and available world data, in agreement with model predictions. The integrated and pTp_{\rm T}-differential measurements are compared with measurements in pp collisions at lower energies and with several recent phenomenological calculations based on the non-relativistic QCD and Color Evaporation models

    Jet fragmentation transverse momentum distributions in pp and p-Pb collisions at s \sqrt{s} , sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    Jet fragmentation transverse momentum (jT_{T}) distributions are measured in proton-proton (pp) and proton-lead (p-Pb) collisions at sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV with the ALICE experiment at the LHC. Jets are reconstructed with the ALICE tracking detectors and electromagnetic calorimeter using the anti-kT_{T} algorithm with resolution parameter R = 0.4 in the pseudorapidity range |η| < 0.25. The jT_{T} values are calculated for charged particles inside a fixed cone with a radius R = 0.4 around the reconstructed jet axis. The measured jT_{T} distributions are compared with a variety of parton-shower models. Herwig and Pythia 8 based models describe the data well for the higher jT_{T} region, while they underestimate the lower jT_{T} region. The jT_{T} distributions are further characterised by fitting them with a function composed of an inverse gamma function for higher jT_{T} values (called the “wide component”), related to the perturbative component of the fragmentation process, and with a Gaussian for lower jT_{T} values (called the “narrow component”), predominantly connected to the hadronisation process. The width of the Gaussian has only a weak dependence on jet transverse momentum, while that of the inverse gamma function increases with increasing jet transverse momentum. For the narrow component, the measured trends are successfully described by all models except for Herwig. For the wide component, Herwig and PYTHIA 8 based models slightly underestimate the data for the higher jet transverse momentum region. These measurements set constraints on models of jet fragmentation and hadronisation

    Measurements of the groomed and ungroomed jet angularities in pp collisions at s \sqrt{s} = 5.02 TeV

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    International audienceThe jet angularities are a class of jet substructure observables which characterize the angular and momentum distribution of particles within jets. These observables are sensitive to momentum scales ranging from perturbative hard scatterings to nonperturbative fragmentation into final-state hadrons. We report measurements of several groomed and ungroomed jet angularities in pp collisions at s \sqrt{s} = 5.02 TeV with the ALICE detector. Jets are reconstructed using charged particle tracks at midrapidity (|η| < 0.9). The anti-kT_{T} algorithm is used with jet resolution parameters R = 0.2 and R = 0.4 for several transverse momentum {p}_{\mathrm{T}}^{\mathrm{ch}} ^{jet} intervals in the 20–100 GeV/c range. Using the jet grooming algorithm Soft Drop, the sensitivity to softer, wide-angle processes, as well as the underlying event, can be reduced in a way which is well-controlled in theoretical calculations. We report the ungroomed jet angularities, λα_{α}, and groomed jet angularities, λα,g_{α,g}, to investigate the interplay between perturbative and nonperturbative effects at low jet momenta. Various angular exponent parameters α = 1, 1.5, 2, and 3 are used to systematically vary the sensitivity of the observable to collinear and soft radiation. Results are compared to analytical predictions at next-to-leading-logarithmic accuracy, which provide a generally good description of the data in the perturbative regime but exhibit discrepancies in the nonperturbative regime. Moreover, these measurements serve as a baseline for future ones in heavy-ion collisions by providing new insight into the interplay between perturbative and nonperturbative effects in the angular and momentum substructure of jets. They supply crucial guidance on the selection of jet resolution parameter, jet transverse momentum, and angular scaling variable for jet quenching studies.[graphic not available: see fulltext
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