173 research outputs found

    Briofitas y pteridofitas en sedimentos del Holoceno de la provincia de Buenos Aires, Argentina

    Get PDF
    Se describen csporJ!i de briu fil a~ y pteridolit~s provcnh.:nlc~ de ~imen to.i. del Holoccno de la Pro\·incia tJc Buenos Aires, Argcntin:l. Se diferenciaron cu.:uro géneros de brio lilas: Ricciu, Riclfo, A!lllroccros y Plumxcrvs )' sicle géneros de ptcridofitas: Piluloria, Anemia, Notl10laenfJ, DotyOpten·s, Cheilomlrt>s o Pclhmr y Pol)1wtJium. ~e determinaron cua· tro especie..~ del género Pllccoeeros : P. !ae1 is, P. umuis, P. hulhiculoms y P. caroli11imws a part ir de sus \'Jriacioncs morfológic:~s. El ;m51isi.s morfológico de los géneros actuales de Ac.liantuceac c.lc la Provincia de Bu~nos Aires permitió asignar l:~s C~JXIra.s fósiles carentes d-e perisporio al género Clwiftmthcs o Pcl!rtt•a. E:,tc !rabajtl con~tituyc b primcr;t t-\1d~ncia del establecimiento de: Jlleridolitas en el .~ rca de Ventania y su rclat:ión con las posihlc~ rutas migratorias entre las noras ptcridofitic:.s :w<linc.-p.1mpeanas, itUslr.tl·antárticas )' austrohrasi· lenas durante el Holoccno. La inform:Jción p:!lcoambk ntol qw..: brind~n las briofit:ls y ptcri· dofitas es difícil de interpretar indcpcndi:.:nte de los rcgi~tro~ ¡mlínicos. La rm:scncia de estos t:u:a e.'SI~ rebcionada con condicicmes amhicntales loc..1 lc~.Sporcs of brJOphyt~s and p~cridophyt~s are dcscrib~d from Holoccnc sc di· mc:nls from Buenos Aires Province, Argentin a. Four genera o( bryorh)1CS: Riaia, Riel/a, Alll· /¡()(.eros and Pllacoceros .:md seven genera of pteridophytcs: Pi!rtlario, Aznl!a, Anemia, Notllo· faena, DOfj10plCris, Ot!!ilamilc.r o Pe/laca and PtHypotlium h:we been dCiermiucd. From their mcrphological \'ariations four spc:cics llclonging to thc gcnu.~ Pf¡acoccros h~\'C. bccn found: P. larn;s, P. rc1111is, P. bulbiculoms and P. curolinilmus . Thc morphological auai)'Si!J of the pre· st:nl da;· gcnc.r;, of Adiant:~ceae from Uut:.m~ Aires Provino: JIIO"-'Ccl 10 cl assify the fo~il sporcs lacking a perispore as Q¡cifamJ:cs or Pcl!aca. This rcsc:'lrch comait utcs lht lirst cvidcnce of thc cstab!ishmcnl of ptcridophytcs in thc arca of Vcntania (Buenos Aires Provincc) and ils relation to the probable rnigratory routc:s during the Holoc..1:ne amiJug thc AndcanPamrc:~ n, Austrai·Anl ilrCiic .1nd ALL~r;l!· Br.17.il ian p1L':ridorh)1k nora. PaiL!Ocnvironmcnl:ll irnpli cations of spores of bryoph)'1es antl preridüphyw, are: tlifliwlt lo inrerprc:l indepcndent of thc po llcn rccords Jnd tl'lcy only yicld information on local cnvironm~ nt ol condi tions.

    Modern cave pollen in an arid environment and its application to describe palaeorecords

    Get PDF
    This paper presents pollen-analytical results of surface sediments from two caves in southeastern Spain, a region of particular interest because of its relatively arid climate and entomophilous-dominated flora. The positive role of aridity on pollen preservation in cave sediments is confirmed, and is reflected by samples with high pollen concentration and number of taxa, and low percentages of indeterminable palynomorphs. Pollen spectra from cave sediments, while strongly influenced by biotic transport, may represent the surrounding vegetation acceptably well, even better than the external pollen rain in which is biased by very abundant production and dispersal of wind-pollinated taxa.Análisis de polen moderno en cuevas con un clima árido y su aplicación para describir los paleoregistros. Se presentan los resultados del análisis polínico de sedimentos superficiales de dos cavidades del SE ibérico, región caracterizada por un clima relativamente árido y una vegetación principalmente entomófila. Queda confirmado el valor de la aridez para la preservación polínica en los sedimentos de cavidades kársticas, encontrándose valores elevados de concentración polínica y del número de taxones, así como bajos porcentajes de pólenes indeterminables. Los espectros polínicos de sedimentos de cuevas, aún estando fuertemente influenciados por el transporte biótico, pueden constituir un buen indicador de la vegetación que crece en los alrededores de la cavidad, incluso mejor que la propia lluvia polínica externa

    Improved heuristic drift elimination with magnetically-aided dominant directions (MiHDE) for pedestrian navigation in complex buildings

    Get PDF
    The main problem of pedestrian dead-reckoning (PDR) using only a body-attached inertial measurement unit is the accumulation of heading errors. The heading provided by magnetometers in indoor buildings is in general not reliable and therefore it is commonly not used. Recently, a new method was proposed called heuristic drift elimination (HDE) that minimises the heading error when navigating in buildings. It assumes that the majority of buildings have their corridors parallel to each other, or they intersect at right angles, and consequently most of the time the person walks along a straight path with a heading constrained to one of the four possible directions. In this article we study the performance of HDE-based methods in complex buildings, i.e. with pathways also oriented at 45°, long curved corridors, and wide areas where non-oriented motion is possible. We explain how the performance of the original HDE method can be deteriorated in complex buildings, and also, how severe errors can appear in the case of false matches with the building's dominant directions. Although magnetic compassing indoors has a chaotic behaviour, in this article we analyse large data-sets in order to study the potential use that magnetic compassing has to estimate the absolute yaw angle of a walking person. Apart from these analysis, this article also proposes an improved HDE method called Magnetically-aided Improved Heuristic Drift Elimination (MiHDE), that is implemented over a PDR framework that uses foot-mounted inertial navigation with an extended Kalman filter (EKF). The EKF is fed with the MiHDE-estimated orientation error, gyro bias corrections, as well as the confidence over that corrections. We experimentally evaluated the performance of the proposed MiHDE-based PDR method, comparing it with the original HDE implementation. Results show that both methods perform very well in ideal orthogonal narrow-corridor buildings, and MiHDE outperforms HDE for non-ideal trajectories (e.g. curved paths) and also makes it robust against potential false dominant direction matchings

    An asymmetric BODIPY triad with panchromatic absorption for high-performance red-edge laser emission

    Get PDF
    © The Royal Society of Chemistry 2015. A rational design of an unprecedented asymmetric cassette triad based entirely on BODIPY chromophores allows efficient light harvesting over the UV-vis spectral region, leading to a bright and stable red-edge laser emission via efficient energy-transfer processes.Peer Reviewe

    A standardized framing for reporting protein identifications in mzIdentML 1.2

    Get PDF
    Inferring which protein species have been detected in bottom-up proteomics experiments has been a challenging problem for which solutions have been maturing over the past decade. While many inference approaches now function well in isolation, comparing and reconciling the results generated across different tools remains difficult. It presently stands as one of the greatest barriers in collaborative efforts such as the Human Proteome Project and public repositories such as the PRoteomics IDEntifications (PRIDE) database. Here we present a framework for reporting protein identifications that seeks to improve capabilities for comparing results generated by different inference tools. This framework standardizes the terminology for describing protein identification results, associated with the HUPO-Proteomics Standards Initiative (PSI) mzIdentML standard, while still allowing for differing methodologies to reach that final state. It is proposed that developers of software for reporting identification results will adopt this terminology in their outputs. While the new terminology does not require any changes to the core mzIdentML model, it represents a significant change in practice, and, as such, the rules will be released via a new version of the mzIdentML specification (version 1.2) so that consumers of files are able to determine whether the new guidelines have been adopted by export software

    Seismology of the Sun : Inference of Thermal, Dynamic and Magnetic Field Structures of the Interior

    Full text link
    Recent overwhelming evidences show that the sun strongly influences the Earth's climate and environment. Moreover existence of life on this Earth mainly depends upon the sun's energy. Hence, understanding of physics of the sun, especially the thermal, dynamic and magnetic field structures of its interior, is very important. Recently, from the ground and space based observations, it is discovered that sun oscillates near 5 min periodicity in millions of modes. This discovery heralded a new era in solar physics and a separate branch called helioseismology or seismology of the sun has started. Before the advent of helioseismology, sun's thermal structure of the interior was understood from the evolutionary solution of stellar structure equations that mimicked the present age, mass and radius of the sun. Whereas solution of MHD equations yielded internal dynamics and magnetic field structure of the sun's interior. In this presentation, I review the thermal, dynamic and magnetic field structures of the sun's interior as inferred by the helioseismology.Comment: To be published in the proceedings of the meeting "3rd International Conference on Current Developments in Atomic, Molecular, Optical and Nano Physics with Applications", December 14-16, 2011, New Delhi, Indi

    Neutron cross-sections for advanced nuclear systems : The n-TOF project at CERN

    Get PDF
    © Owned by the authors, published by EDP Sciences, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n-TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.Peer reviewedFinal Published versio

    238U(n, γ) reaction cross section measurement with C 6D6 detectors at the n-TOF CERN facility

    Get PDF
    This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,γ) cross section measurement performed at n-TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction.Peer reviewe

    High accuracy 234U(n,f) cross section in the resonance energy region

    Get PDF
    New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n-TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n-TOF neutron flux
    corecore