Culturally modified trees and forest structure at a Kawesqar ancient settlement at Rio Batchelor, western Patagonia

Indigenous land use occurring on temporal scales over centuries or millennia shapes forests in specific ways and influences the dynamics of forest ecosystems. It is challenging to study such land use, but analysis of "culturally modified trees" (CMTs) can give precise spatial and temporal information on past land use by indigenous people. The aim of this study was to increase our knowledge of indigenous use of land and resources in Nothofagus forests by identifying CMTs and analyzing the forest structure dynamics in an ancient Kawesqar settlement site in western Patagonia. Our results show that there are CMTs at Rio Batchelor and that the forest structure varies significantly within the site, indicating that Kawesqar people altered the forest by extracting various resources. We conclude that CMT studies have great potential in Nothofagus forests in southernmost America, but also face specific challenges due to environmental conditions and lack of corroborating historical information

Reporte del hallazgo de árboles culturalmente modificados en bosques costeros de Nothofagus Betuloides (Mirb.) Oerst 1871 (Nothofagaceae) por pueblos canoeros de la Patagonia austral y Tierra del Fuego

Los bosques templados costeros pluviales de la Patagonia austral y Tierra del Fuego cons- tituyen una expresión florística y ecológica de características propias y muy distintas al resto de las formaciones vegetales del continente americano (Pisano, 1997). Aquellos de carác- ter “primario” o en estados sucesionales avan- zados son actualmente remanentes escasos de los procesos antrópicos de degradación ambiental relacionados a la extracción y explo- tación de recursos naturales, que sobreviven gracias a su aislamiento de caminos o rutas de explotación, o bien, por su resguardo geográ- fico a eventos climáticos de gran envergadura (i.e. volteo masivo por temporales de viento) (Pisano, 1997; Promis, Cruz, Reif &Gärtner, 2008). Conservan en su estructura información de enorme y singular valor ecológico, siendo testigos vivos de procesos ambientales y paleoclimáticos, estrechamente ligados a las dinámicas históricas del paisaje litoral de los canales patagónicos (Holz, Haberle, Veblen, De Pol Holz, Southon, 2012; Koch & Kilian, 2002; Villagrán, 2018)but rarely on both. In this study of fire history in western Patagonia (47-48° S. A su vez, es de esperar, que dichas dinámicas podrían comprender en parte o en su totali- dad, una historia estrechamente ligada al ser humano, al menos desde el retroceso glacial y posterior ocupación de los canales patagó- nicos por cazadores recolectores marinos o pueblos canoeros (Emperaire, 1955)

Observation of low- and high-energy gamow-teller phonon excitations in nuclei

Y. Fujita et al. ; 5 pags. ; 3 figs. PACS numbers: 24.30.Cz, 25.55.Kr, 27.40.+zGamow-Teller (GT) transitions in atomic nuclei are sensitive to both nuclear shell structure and effective residual interactions. The nuclear GT excitations were studied for the mass number A=42, 46, 50, and 54 >f-shell> nuclei in (He3, t) charge-exchange reactions. In the Ca42→Sc42 reaction, most of the GT strength is concentrated in the lowest excited state at 0.6 MeV, suggesting the existence of a low-energy GT phonon excitation. As A increases, a high-energy GT phonon excitation develops in the 6-11 MeV region. In the Fe54→Co54 reaction, the high-energy GT phonon excitation mainly carries the GT strength. The existence of these two GT phonon excitations are attributed to the 2 fermionic degrees of freedom in nuclei. © 2014 American Physical Society.This work was in part supported by MEXT, Japan (Grants No. 13002001, No. 15540274, and No. 18540270); MICINN, Spain (Grant No. FPA200806419-C02-01). Y. F. and B. R. acknowledge the support of the Japan-Spain collaboration program by JSPS and CSIC.Peer Reviewe

High-resolution study of Gamow-Teller excitations in the Ca42(He3,t)Sc42 reaction and the observation of a “low-energy super-Gamow-Teller state”

Y. Fujita et al.; 15 pags.; 6 figs.; 7 tabs.; PACS number(s): 21.10.Hw, 25.55.Kr, 27.40.+z, 25.40.Ep© 2015 American Physical Society. To study the Gamow-Teller (GT) transitions from the Tz=+1 nucleus Ca42 to the Tz=0 nucleus Sc42, where Tz is the z component of isospin T, we performed a (p,n)-type (He3,t) charge-exchange reaction at 140 MeV/nucleon and scattering angles around 0. With an energy resolution of 29 keV, states excited by GT transitions (GT states) could be studied accurately. The reduced GT transition strengths B(GT) were derived up to the excitation energy of 13 MeV, assuming the proportionality between the cross sections at 0 and B(GT) values. The main part of the observed GT transition strength is concentrated in the lowest 0.611-MeV, Jπ=1+ GT state. All the other states at higher energies are weakly excited. Shell-model calculations could reproduce the gross feature of the experimental B(GT) distribution, and random-phase-approximation calculations including an attractive isoscalar interaction showed that the 0.611-MeV state has a collective nature. It was found that this state has all of the properties of a >low-energy super-Gamow-Teller state.> It is expected that low-lying Jπ=1+ GT states have T=0 in the Tz=0 nucleus Sc42. However, T=1 states are situated in a higher energy region. Assuming an isospin-analogous structure in A=42 isobars, analogous T=1, 1+ states are also expected in Ca42. Comparing the Ca42(He3,t)Sc42 and Ca42(p,p′) spectra measured at 0, candidates for T=1 GT states could be found in the 10-12-MeV region of Sc42. They were all weakly excited. The mass dependence of the GT strength distributions in Sc isotopes is also discussed.Y.F. also acknowledges the support of MEXT, Japan under Grants No. 18540270, No. 22540310, and No. 15K05104. Y.F. and B.R. are grateful for the support of the Japan-Spain collaboration program by JSPS and CSIC; A.A., E.E.A., and B.R. are thankful for the support of Spanish Ministry under Grants No. FPA2005-03993, No. FPA2008-06419-C02-01, and No. FPA2011-24553. G.S. acknowledges the support of TUBITAK, Turkey under Research Scholarship No. BIDEB 2214. J.M.D., C.J.G., R.M., G.P., and R.G.T.Z. are grateful for the support of the US NSF under Grants No. PHY-0606007 and No. PHY-0822648 (JINA). M.C., J.G., and A.K. acknowledge the support of the OTKA Foundation, Hungary, under Grant No. K106035. This work was in part supported by the RIKENCNS joint research project on large-scale nuclear-structure calculations.Peer Reviewe

Catching Element Formation In The Act

Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions.Comment: 14 pages including 3 figure

Culturally modified trees and forest structure at a Kawésqar ancient settlement at Río Batchelor, western Patagonia

Ajuts: This study was funded by Magnus Bergvalls Stiftelse, Sweden; Marie Skodowska-Curie Research and Innovation Staff Exchange (RISE) Program (SuFoRun #691149); Gifford Hickey, from Spring Creek Conservation; and Laboratoire ESE, Université Paris-Saclay.Indigenous land use occurring on temporal scales over centuries or millennia shapes forests in specific ways and influences the dynamics of forest ecosystems. It is challenging to study such land use, but analysis of "culturally modified trees" (CMTs) can give precise spatial and temporal information on past land use by indigenous people. The aim of this study was to increase our knowledge of indigenous use of land and resources in Nothofagus forests by identifying CMTs and analyzing the forest structure dynamics in an ancient Kawésqar settlement site in western Patagonia. Our results show that there are CMTs at Río Batchelor and that the forest structure varies significantly within the site, indicating that Kawésqar people altered the forest by extracting various resources. We conclude that CMT studies have great potential in Nothofagus forests in southernmost America, but also face specific challenges due to environmental conditions and lack of corroborating historical information

Reporte del hallazgo de árboles culturalmente modificados en bosques costeros de Nothofagus Betuloides (Mirb.) Oerst 1871 (Nothofagaceae) por pueblos canoeros de la Patagonia austral y Tierra del Fuego

Los bosques templados costeros pluviales de la Patagonia austral y Tierra del Fuego cons- tituyen una expresión florística y ecológica de características propias y muy distintas al resto de las formaciones vegetales del continente americano (Pisano, 1997). Aquellos de carác- ter "primario" o en estados sucesionales avan- zados son actualmente remanentes escasos de los procesos antrópicos de degradación ambiental relacionados a la extracción y explo- tación de recursos naturales, que sobreviven gracias a su aislamiento de caminos o rutas de explotación, o bien, por su resguardo geográ- fico a eventos climáticos de gran envergadura (i.e. volteo masivo por temporales de viento) (Pisano, 1997; Promis, Cruz, Reif &Gärtner, 2008). Conservan en su estructura información de enorme y singular valor ecológico, siendo testigos vivos de procesos ambientales y paleoclimáticos, estrechamente ligados a las dinámicas históricas del paisaje litoral de los canales patagónicos (Holz, Haberle, Veblen, De Pol Holz, Southon, 2012; Koch & Kilian, 2002; Villagrán, 2018)but rarely on both. In this study of fire history in western Patagonia (47-48° S. A su vez, es de esperar, que dichas dinámicas podrían comprender en parte o en su totali- dad, una historia estrechamente ligada al ser humano, al menos desde el retroceso glacial y posterior ocupación de los canales patagó- nicos por cazadores recolectores marinos o pueblos canoeros (Emperaire, 1955)