2,262 research outputs found
The Tapuia of Northeastern Brazil in Dutch sources (1628–1648)
This book presents the transcriptions and annotated translations of fifteen key historical documents concerning the Tapuia indigenous people written just before and during the Dutch occupation of northeastern Brazil. The selected documents vary widely in type, including letters, descriptions, reports, first-person declarations, diaries, and transcripts of interrogations, thereby showcasing different perspectives and audiences. Some of the documents were authored by European writers, while others register indigenous voices somewhat more directly in the form of interviews or declarations.These texts provide important first-hand information about the Tapuia and other indigenous peoples during the Dutch conquest, revealing their cultural practices and knowledge while also detailing their strategic engagements with each other and with different European colonizers.Horizon 2020(H2020)ERC Agreement No. 715423Heritage of Indigenous People
Nouveaux apports sur l’archéologie du littoral de Guyane : de la préhistoire à la conquête
En Guyane française, les recherches archĂ©ologiques structurĂ©es ne datent que du dĂ©but des annĂ©es 1970. Elles furent synthĂ©tisĂ©es par StĂ©phen Rostain au dĂ©but des annĂ©es 1990. Le cadre chrono-culturel Ă©tabli alors se concentrait surtout sur la bande littorale entre les rivières de Kourou et de l’Oyapock et sur la pĂ©riode entre 900 et 1700 de notre ère. Cette Ă©tude rĂ©sume les rĂ©sultats de six fouilles archĂ©ologiques prĂ©ventives plus rĂ©centes. Celles-ci permettent d’abord d’étoffer le cadre chrono-culturel de la prĂ©histoire de ce dĂ©partement français. En effet des donnĂ©es nouvelles Ă©largissent substantiellement ce cadre sur l’Âge archaĂŻque et sur la pĂ©riode cĂ©ramique ancienne, deux Ă©poques inconnues jusque-lĂ . De nouveaux Ă©lĂ©ments renouvellent aussi certaines perspectives de la pĂ©riode cĂ©ramique rĂ©cente, en particulier sur les pratiques funĂ©raires, les complexes cĂ©ramiques et l’alimentation des AmĂ©rindiens.In French Guiana, structured archaeological research only started in the early 1970s. Its results have been synthesized by StĂ©phen Rostain twenty year later. The proposed chronocultural framework focused mainly on the coastal plains situated between the Oyapock and Kourou Rivers for the Late Ceramic Age, between AD 900 and 1700. This study presents the condensed results of six recent compliance archaeological excavations. They permit us firstly to enrich the existing framework of this overseas French department by presenting new data concerning the Archaic and Early Ceramic Ages, hitherto undiscovered episodes, substantially enlarging this framework. Furthermore, new elements concerning the Late Ceramic Age renew certain aspects, notably concerning funerary practices, ceramic complexes and food consumption of the prehistoric Amerindians.Na Guiana Francesa, pesquisas arqueolĂłgicas estruturadas sĂł começaram no inĂcio da dĂ©cada de 1970 e seus resultados foram sintetizados por StĂ©phen Rostain no inĂcio dos anos 1990. O quadro cronocultural proposto focava principalmente nas planĂcies costeiras situadas entre os rios Oiapoque e Kourou para o PerĂodo Cerâmico tardio, entre 900 e 1700 AD. Este estudo apresenta os resultados condensados de seis escavações de arqueologia preventiva. Eles nos permitem, primeiramente, enriquecer o quadro existente deste departamento ultramarino francĂŞs; alĂ©m disso, sĂŁo apresentados aqui novos dados sobre os PerĂodos Cerâmicos arcaico e inicial, episĂłdios atĂ© entĂŁo nĂŁo descobertos, ampliando substancialmente esse panorama. Finalmente, novos elementos relativos ao PerĂodo Cerâmico tardio renovam certos aspectos, notadamente, sobre práticas funerárias, complexos cerâmicos e consumo de alimentos das populações amerĂndias prĂ©-histĂłricas
Species-specific and distance-dependent dispersive behaviour of forisomes in different legume species
Archaeological investigations between Cayenne Island and the Maroni river : a cultural sequence of western coastal Franche Guiana from 5000 BP to present
2 septembre 2015 Université de Leyde Membres du Jury Directeurs de thèseCorinne L. Hofman, Professeure, université de LeydeArie Boomert, Chercheur, université de LeydeRapporteurs Maarten E.R.G.N. Jansenn, Professeur, université de LeydeEduardo Góes Neves, Professeur, Musée d’archéologie et d’ethnologie de l’université de São PauloEithne B. Carlin, Chercheuse, université de LeydeExaminateurs Humphrey H. H. Kanhai, Professeur, université de LeydeDavid R. Fontijn, Professeur, université de Leyd..
On the classification of type D spacetimes
We give a classification of the type D spacetimes based on the invariant
differential properties of the Weyl principal structure. Our classification is
established using tensorial invariants of the Weyl tensor and, consequently,
besides its intrinsic nature, it is valid for the whole set of the type D
metrics and it applies on both, vacuum and non-vacuum solutions. We consider
the Cotton-zero type D metrics and we study the classes that are compatible
with this condition. The subfamily of spacetimes with constant argument of the
Weyl eigenvalue is analyzed in more detail by offering a canonical expression
for the metric tensor and by giving a generalization of some results about the
non-existence of purely magnetic solutions. The usefulness of these results is
illustrated in characterizing and classifying a family of Einstein-Maxwell
solutions. Our approach permits us to give intrinsic and explicit conditions
that label every metric, obtaining in this way an operational algorithm to
detect them. In particular a characterization of the Reissner-Nordstr\"{o}m
metric is accomplished.Comment: 29 pages, 0 figure
Bioinformatics-based assessment of the relevance of candidate genes for mutation discovery
The bioinformatics resources provide a wide range of tools that can be applied in different areas of mutation screening. The enormous and constantly increasing amount of genomic data obtained in plant-oriented molecular studies requires the development of efficient techniques for its processing. There is a wide range of bioinformatics tools which can aid in the course of mutation discovery. The following chapter focuses mainly on the application of different tools and resources to facilitate a Targeting-Induced Local Lesions in Genomes (TILLING) analysis. TILLING is a technique of reverse genetics that applies a traditional mutagenesis to create DNA libraries of mutagenised individuals that are then subjected to high-throughput screening for the identification of mutations. The bioinformatics tools have shown to be useful in supporting the process of candidate gene selection for mutation screening. The availability of bioinformatics software and experimental data repositories provides a powerful tool which enables a process of multi-database mining. The existing raw experimental data (genomics-related information, expression data, annotated ontologies) can be interpreted in terms of a new biological context. This may help in selecting the proper candidate gene for mutation discovery that is controlling the target phenotype. The mutation screening using a TILLING strategy requires a former knowledge of the full genomic sequence of the gene which is of interest. Depending on whether a fully sequenced genome of a particular species is available, different bioinformatics tools can facilitate this process. Specific tools can be also useful for the identification of possible gene paralogs which may mask the effect of mutated gene. Bioinformatics resources can also support the selection of gene fragments most prone to acquire a deleterious nucleotide change. Finally, there are available tools enabling a proper design of oligonucleotide primers for the amplification of a gene fragment for the purpose of mutation screening
Detailed Radio to Soft Gamma-ray Studies of the 2005 Outburst of the New X-ray Transient XTE J1818-245
XTE J1818-245 is an X-ray nova that experienced an outburst in 2005, first
seen by the RXTE satellite. The source was observed simultaneously at various
wavelengths up to soft gamma-rays with the INTEGRAL satellite, from 2005
February to September. X-ray novae are extreme systems that often harbor a
black hole, and are known to emit throughout the electromagnetic spectrum when
in outburst. We analyzed radio, (N)IR, optical, X-ray and soft gamma-ray
observations and constructed simultaneous broad-band X-ray spectra. Analyzing
both the light curves in various energy ranges and the hardness-intensity
diagram enabled us to study the long-term behavior of the source. Spectral
parameters were typical of the Soft Intermediate States and the High Soft
States of a black hole candidate. The source showed relatively small spectral
variations in X-rays with considerable flux variation in radio. Spectral
studies showed that the accretion disc cooled down from 0.64 to 0.27 keV in 100
days and that the total flux decreased while the relative flux of the hot
medium increased. Radio emission was detected several times, and,
interestingly, five days after entering the HSS. Modeling the spectral energy
distribution from the radio to the soft gamma-rays reveals that the radio
flares arise from several ejection events. XTE J1818-245 is likely a black hole
candidate transient source that might be closer than the Galactic Bulge. The
results from the data analysis trace the physical changes that took place in
the system at a maximum bolometric luminosity of (0.4-0.9)e38 erg/s (assuming a
distance between 2.8-4.3 kpc) and they are discussed within the context of disc
and jet models.Comment: Accepted for publication in Astronomy and Astrophysics. 11 Figures, 3
Table
Phloem loading in the sucrose-export-defective (SXD-1) mutant maize is limited by callose deposition at plasmodesmata in bundle sheath-vascular parenchyma interface
Using Lucifer Yellow we have demonstrated that the phloem-loading pathway from the mesophyll to the bundle sheath-vascular parenchyma interface in Zea mays source leaves follows a symplasmic route in small and intermediate vascular bundles in control as well as in the green sections of mutant sucrose-export-defective (SXD-1) plants. In the anthocyanin-rich mutant leaf sections, Lucifer Yellow transport was prohibited along the same path, at the bundle sheath-vascular parenchyma interface in particular. Plasmodesmata at the latter interface in SXD-1 anthocyanin-rich leaf sections appear to be structurally altered through callose deposition at the plasmodesmal orifices. We suggest that a transport bottleneck at the bundle sheath-vascular parenchyma interface is thus orchestrated and regulated through callose formation, preventing symplasmic transport across this important loading interface
Wave Propagation and Jet Formation in the Chromosphere
We present the results of numerical simulations of wave propagation and jet
formation in solar atmosphere models with different magnetic field
configurations. The presence in the chromosphere of waves with periods longer
than the acoustic cutoff period has been ascribed to either strong inclined
magnetic fields, or changes in the radiative relaxation time. Our simulations
include a sophisticated treatment of radiative losses, as well as fields with
different strengths and inclinations. Using Fourier and wavelet analysis
techniques, we investigate the periodicity of the waves that travel through the
chromosphere. We find that the velocity signal is dominated by waves with
periods around 5 minutes in regions of strong, inclined field, including at the
edges of strong flux tubes where the field expands, whereas 3-minute waves
dominate in regions of weak or vertically oriented fields. Our results show
that the field inclination is very important for long-period wave propagation,
whereas variations in the radiative relaxation time have little effect.
Furthermore, we find that atmospheric conditions can vary significantly on
timescales of a few minutes, meaning that a Fourier analysis of wave
propagation can be misleading. Wavelet techniques take variations with time
into account and are more suitable analysis tools. Finally, we investigate the
properties of jets formed by the propagating waves once they reach the
transition region, and find systematic differences between the jets in inclined
field regions and those in vertical field regions, in agreement with
observations of dynamic fibrils.Comment: 27 pages, 29 figures; accepted for publication in Astrophysical
Journa
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