The Collimated Jet Source in IRAS 16547-4247: Time Variation, Possible Precession, and Upper Limits to the Proper Motions Along the Jet Axis

The triple radio source detected in association with the luminous infrared source IRAS 16547-4247 has previously been studied with high angular resolution and high sensitivity with the Very Large Array (VLA) at 3.6-cm wavelength. In this paper, we present new 3.6 cm observations taken 2.68 years after the first epoch that allow a search for variability and proper motions, as well as the detection of additional faint sources in the region. We do not detect proper motions along the axis of the outflow in the outer lobes of this source at a 4-$\sigma$ upper limit of $\sim$160 km s$^{-1}$. This suggests that these lobes are probably working surfaces where the jet is interacting with a denser medium. However, the brightest components of the lobes show evidence of precession, at a rate of $0\rlap.^\circ08$ yr$^{-1}$ clockwise in the plane of the sky. It may be possible to understand the distribution of almost all the identified sources as the result of ejecta from a precessing jet. The core of the thermal jet shows significant variations in flux density and morphology. We compare this source with other jets in low and high mass young stars and suggest that the former can be understood as a scaled-up version of the latter.Comment: 26 pages, 9 figure

Aged but withstanding: Maintenance of growth rates in old pines is not related to enhanced water-use efficiency

Growth of old trees in cold-limited forests may benefit from recent climate warming and rising atmospheric CO2 concentrations (ca) if age-related constraints do not impair wood formation. To test this hypothesis, we studied old Mountain pine trees at three Pyrenean high-elevation forests subjected to cold-wet (ORD, AIG) or warmer-drier (PED) conditions. We analyzed long-term trends (1450–2008) in growth (BAI, basal area increment), maximum (MXD) and minimum (MID) wood density, and tree-ring carbon (δ13C) and oxygen (δ18O) isotope composition, which were used as proxies for intrinsic water-use efficiency (iWUE) and stomatal conductance (gs), respectively. Old pines showed positive (AIG and ORD) or stable (PED) growth trends during the industrial period (since 1850) despite being older than 400 years. Growth and wood density covaried from 1850 onwards. In the cold-wet sites (AIG and ORD) enhanced photosynthesis through rising ca was likely responsible for the post-1850 iWUE improvement. However, uncoupling between BAI and iWUE indicated that increases in iWUE were not responsible for the higher growth but climate warming. A reduction in gs was inferred from increased δ18O for PED trees from 1960 onwards, the warmest site where the highest iWUE increase occurred (34%). This suggests that an emergent drought stress at warm-dry sites could trigger stomatal closure to avoid excessive transpiration. Overall, carbon acquisition as lasting woody pools is expected to be maintained in aged trees from cold and high-elevation sites where old forests constitute unique long-term carbon reservoirs.We are very grateful to several projects financed by “Organismo Autónomo de Parques Nacionales” (projects 12/2008 387/2011). E.G. was funded by a Juan de la Cierva post-doctoral research contract (FJCI-2014-19615, MEC, Spain). Spanish (AMB95-0160, CGL2011-26654) and EU projects ISONET (contract EV K2-2001-00237) and MILLENNIUM (017008–2) also supported this study by contributing additional datasets

Plasticity in dendroclimatic response across the distribution range of Aleppo pine (Pinus halepensis)

We investigated the variability of the climate-growth relationship of Aleppo pine across its distribution range in the Mediterranean Basin. We constructed a network of tree-ring index chronologies from 63 sites across the region. Correlation function analysis identified the relationships of tree-ring index to climate factors for each site. We also estimated the dominant climatic gradients of the region using principal component analysis of monthly, seasonal, and annual mean temperature and total precipitation from 1,068 climatic gridpoints. Variation in ring width index was primarily related to precipitation and secondarily to temperature. However, we found that the dendroclimatic relationship depended on the position of the site along the climatic gradient. In the southern part of the distribution range, where temperature was generally higher and precipitation lower than the regional average, reduced growth was also associated with warm and dry conditions. In the northern part, where the average temperature was lower and the precipitation more abundant than the regional average, reduced growth was associated with cool conditions. Thus, our study highlights the substantial plasticity of Aleppo pine in response to different climatic conditions. These results do not resolve the source of response variability as being due to either genetic variation in provenance, to phenotypic plasticity, or a combination of factors. However, as current growth responses to inter-annual climate variability vary spatially across existing climate gradients, future climate-growth relationships will also likely be determined by differential adaptation and/or acclimation responses to spatial climatic variation. The contribution of local adaptation and/or phenotypic plasticity across populations to the persistence of species under global warming could be decisive for prediction of climate change impacts across populations. In this sense, a more complex forest dynamics modeling approach that includes the contribution of genetic variation and phenotypic plasticity can improve the reliability of the ecological inferences derived from the climate-growth relationships.This work was partially supported by Spanish Ministry of Education and Science co-funded by FEDER program (CGL2012-31668), the European Union and the National Ministry of Education and Religion of Greece (EPEAEK- Environment – Archimedes), the Slovenian Research Agency (program P4-0015), and the USDA Forest Service. The cooperation among international partners was supported by the COST Action FP1106, STREeSS

Reseñas de libros

[EN] García Bueno, Antonio. Dibujando la Alhambra y su Entorno (por Antonio J. Gómez-Blanco Pontes) pp. 4.-- Pozo, José M.; García-Diego, Hector y García, Izaskun ( por Carlos Montes Serrano) pp. 5.-- Laura Carlevaris, Mónica Filippa (coordinadoras)(por Antonio Álvaro Tordesillas) pp. 5 y 6.-- Esteve Secall, Carlos E. La ciencia gnomónica en la España del siglo de Oro (por Joaquín Casado de Amezúa Vázquez ) pp. 6 y 7.-- Franco Taboada, José Antonio. Geometría descriptiva para la representación arquitectónica (por Lluís Villanueva Bartrina) pp. 7 y 8.--Raposo Grau, Javier Fco; Butragueño Díaz-Guerra y Paredes Maldonado, Miguel. La ciudad como espacio de relaciones dinámicas (por Margarita de Luxán García de Diego) pp. 8 y 9.-- Castellanos Gómez, Raúl. Plan Poché (por Daniel García-Escudero) pp. 9 y 10.-- Gutiérrez Mozo, María Alia; Castilla Pascual, Francisco Javier y Real Tomás, María del Carmen. 70 años de arquitectura en Albacete: 1936-2006 ( por Javier Poyatos Sebastián) pp. 10 y 11.-- García Sánchez, María Teresa. De la ciudad en vibración al ser resonante: una investigación a propósito de los conciertos de campanas de Llorenç Barber ( por Fernando Ochoa Gómez) pp. 11.-- Pernas Alonso, Inés. Escaleras de piedra en los conjuntos monásticos de la provincia de Ourense entre los siglos xVI y xVIII. Análisis gráfico (por José Antonio Franco Taboada) pp. 12 y 13.-- Rodríguez Moreno, Dª Concepción. El palacio de Pedro I en los Reales Alcázares de Sevilla: estudio y análisis (por Joaquín Casado de Amezúa) pp. 13 y 14.—Jeremías, Pablo y Gutierrez, Juan. Tiempo de arquitectura ( por Carlos L. Marcos) pp. 14 y 15.-- Domingo Gresa, Jorge. El dibujo de arquitectura en la formación de la ciudad de Alicante: Fondo Documental del Archivo Municipal (1691-1860)(por Gaspar Jaén i Urbàn)pp.15.-- García-Solera, Javier. Dibujos y palabras en la habitación tranquila (por Gaspar Jaen) pp. 16 y 17.—Anne Griswold Tyng (1920-2011)( por Noelia Galván Desvaux)pp. 18 y 19 .-- Oscar Niemeyer Un adiós al último maestro del siglo XX(por Noelia Galván Desvaux)pp. 20 y 21Gómez-Blanco Pontes, AJ.; Montes Serrano, C.; Tordesillas, AÁ.; Casado De Amezúa Vázquez, J.; Villanueva Bartrina, L.; De Luxán García De Diego, M.; García-Escudero, D.... (2013). Reseñas de libros. EGA. Revista de Expresión Gráfica Arquitectónica. 18(21):4-21. https://doi.org/10.4995/ega.2013.1708SWORD421182

Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE

This study was funded by the WSL-internal COSMIC project (5233.00148.001.01), the ETHZ (Laboratory of Ion Beam Physics), the Swiss National Science Foundation (SNF Grant 200021L_157187/1), and as the Czech Republic Grant Agency project no. 17-22102s.Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14C content in 484 individual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct 14C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved 14C measurements are needed.Publisher PDFPeer reviewe

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

Spatial diversity of recent trends in Mediterranean tree growth

Increasing temperatures and shifting precipitation regimes define the Mediterranean Basin (MB) as one of the world’s most sensitive climate change hot spots. Among various ecological effects, disruptions in the growth-climate response of Mediterranean forest species have been recently observed. Complex topographical and climatological factors, however, may result in contrasting patterns of recent tree growth, with their biotic and abiotic drivers often remaining debatable. Here, we compile dendrochronological evidence from 878 cases at 645 sites reported in 66 peer-reviewed publications to assess modern (post-1970) growth trends across the MB (30°–46° N and 10° W–40° E). This collection mainly reveals positive trends in temperate environments across the northwestern part of the Basin, whereas negative trends were often found at xeric sites in the southwestern and eastern regions. Although these response patterns are indicative for both beneficial as well as detrimental effects of climate change on pan-Mediterranean forest ecosystem function and productivity, our review is slightly biased by selective sampling efforts that focused on higher elevations and older trees within a few countries in the northwest. This imbalance emphasizes the need for more evenly distributed study sites and age classes that better reflect ecological rather than political and methodological criteria