1,686 research outputs found
Migration Patterns in Male Great Bustards (Otis tarda)
5 paginas, 1 figura y 1 tableThe Great Bustard (Otis tarda) is distributed from Iberia and Morocco in the west to China in the east and has been considered sedentary in all but the northern and eastern parts of its range (Gewalt 1959, Glutz et al. 1973, Cramp and Simmons 1980). However, some studies have reported seasonal changes in population numbers in different areas in the Iberian Peninsula (Hidalgo and Carranza 1990, Alonso et al.
1995), suggesting that the species is a partial migrant (sensu Terrill and Able 1988) in this region. We describe seasonal movements of marked adult male Great Bustards and discuss observed patterns in relation to the following questions: (1) Do migratory males display interannual fidelity to breeding and postbreeding areas? (2) Do males travel significantly
farther than females in their seasonal movements?
We also suggest several hypotheses that
could explain patterns of partial and differential migration in male Great Bustards.This study is a contribution to DGICYT-project
PB94–0068.Peer reviewe
Evaluation of captive breeding as a method to conserve threatened Great Bustard populations.
6 paginas y 1 tableThe recent Great Bustard Action Plan summarizes de main recommended lines of action to preserve current populations and their habitats in Europe. Among others, captive breeding is mentioned as a method to save clutches found in the field whose hatching success probability is suspected to be low for any reason. Birds hatched from these clutches have been used to either build up small captive-breeding flocks that ensure preservation of the genetic pool of seriously threatened populations once these may be extinct, or to be released into the natural populations as juveniles. In this paper we evaluate the viability of
captive breeding in the light of new results of a recent study of juvenile Great Bustards
during their maternal dependence period, family break-up and dispersal. The few data
available on survival of captive-bred young after being released suggest that they suffer a high mortality, probably due to the lack of the experience acquired in natural conditions from their mothers. The negative effects of imprinting by their human keepers, particularly in relation with display and mating, has not been sufficiently investigated. These and other
aspects make captive breeding questionable as an effective method, as compared with
habitat protection measures.PB94-0068 of the Dirección General de Investigacion Cientifica y TecnicaPeer reviewe
Migration Patterns in Male Great Bustards (Otis tarda)
5 paginas, 1 figura y 1 tableThe Great Bustard (Otis tarda) is distributed from Iberia and Morocco in the west to China in the east and has been considered sedentary in all but the northern and eastern parts of its range (Gewalt 1959, Glutz et al. 1973, Cramp and Simmons 1980). However, some studies have reported seasonal changes in population numbers in different areas in the Iberian Peninsula (Hidalgo and Carranza 1990, Alonso et al.
1995), suggesting that the species is a partial migrant (sensu Terrill and Able 1988) in this region. We describe seasonal movements of marked adult male Great Bustards and discuss observed patterns in relation to the following questions: (1) Do migratory males display interannual fidelity to breeding and postbreeding areas? (2) Do males travel significantly
farther than females in their seasonal movements?
We also suggest several hypotheses that
could explain patterns of partial and differential migration in male Great Bustards.This study is a contribution to DGICYT-project
PB94–0068.Peer reviewe
Searching for Trans Ethyl Methyl Ether in Orion KL
We report on the tentative detection of Ethyl Methyl Ether (tEME),
, through the identification of a large number of rotational
lines from each one of the spin states of the molecule towards Orion KL. We
also search for --n-propanol, , an isomer
of tEME in the same source. We have identified lines of both species in the
IRAM 30m line survey and in the ALMA Science Verification data. We have
obtained ALMA maps to establish the spatial distribution of these species.
Whereas tEME mainly arises from the compact ridge component of Orion,
Gt-n-propanol appears at the emission peak of ethanol (south hot core). The
derived column densities of these species at the location of their emission
peaks are and
for tEME and Gt-n-propanol,
respectively. The rotational temperature is for both molecules. We
also provide maps of , , , , and
to compare the distribution of these organic saturated O-bearing
species containing methyl and ethyl groups in this region. Abundance ratios of
related species and upper limits to the abundances of non-detected ethers are
provided. We derive an abundance ratio in the
compact ridge of Orion.Comment: Accepted in A&A Letter
Tumor location on electroporation therapies by means of multi-electrode structures and machine learning
Electroporation is a phenomenon produced in the cell membrane when it is exposed to high pulsed electric fields that increases its permeability. Among other application fields, this phenomenon can be exploited in a clinical environment for tumor ablation therapies. In this context to achieve optimum results, it is convenient to focus the treatment on the tumor tissue to minimize side effects. In this work, a pre-treatment tumor location method is developed, with the purpose of being able to precisely target the therapy. This is done by taking different impedance measurements with a multi-output electroporation generator in conjunction with a multi-electrode structure. Data are processed by means of a vector of independent artificial neural networks, trained and tested with simulation data, and validated with phantom gels. This algorithm proved to provide suitable accuracy in spite of the low electrode count compared to the number of electrodes of a standard electrical impedance tomography device
Global characterization and target identification of piRNAs and endo-siRNAs in mouse gametes and zygotes
44 p.-1 tab.-10 fig.A set of small RNAs known as rasRNAs (repeat-associated small RNAs) have been related to the down-regulation of Transposable Elements (TEs) to safeguard genome integrity. Two key members of the rasRNAs group are piRNAs and endo-siRNAs. We have performed a comparative analysis of piRNAs and endo-siRNAs present in mouse oocytes, spermatozoa and zygotes, identified by deep sequencing and bioinformatic analysis. The detection of piRNAs and endo-siRNAs in the spermatozoa and revealed also in zygotes, hints to their potential delivery to oocytes during fertilization. However, a comparative assessment of the three cell types indicates that both piRNAs and endo-siRNAs are mainly maternally inherited. Finally, we have assessed the role of the different rasRNA molecules in connection with amplification processes by way of the "ping-pong cycle". Our results suggest that the ping-pong cycle can act on other rasRNAs, such as tRNA- and rRNA-derived fragments, thus not only being restricted to TEs during gametogenesis. © 2014 Elsevier B.V.This work was funded by grants from The European Chemical Industry Council Long-range Research Initiative (CEFIC-LRi), from the MEDDTL (11-MRESPNRPE-9-CVS-072), France, from the CSIC (PIE 201020E016), Spain.Peer reviewe
Coherent artifact and time-dependent polarization in amplified ultrafast erbium-doped fibre lasers
Mode-locked erbium-doped fibre lasers are ultrashort pulsed sources widely studied due to their versatility and multiple applications in the near infrared range. Here we present the experimental study of the emission of a passive mode-locked erbium-doped fibre laser with an amplification stage outside the cavity by means of Frequency Resolved Optical Gating (FROG) and spectral interferometry. Due to shot-to-shot instabilities, the FROG traces can be understood as the combination of two different traces, corresponding to the coherent artifact and the average pulse characteristics. We have modified a Principal Components Generalized Projections Algorithm, in order to make it able to retrieve efficiently both the coherent artifact and the average pulse. In addition, we study the temporal dependence of the polarization, showing that the pulses present time-dependent polarization with a stable spectral relative phase between the horizontal and vertical projections. Up to our knowledge, this is the first experimental study that shows the FROG measurements of unstable pulse trains associated with the coherent artifact and analyses the time-dependent polarization in ultrafast fibre lasers
Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Vinyl Cyanide in Orion-KL
New laboratory data of CHCHCN (vinyl cyanide) in its ground and
vibrationally excited states at the microwave to THz domain allow searching for
these excited state transitions in the Orion-KL line survey.
Frequency-modulated spectrometers combined into a single broadband 50-1900 GHz
spectrum provided measurements of CHCHCN covering a spectral range of
18-1893 GHz, whose assignments was confirmed by Stark modulation spectra in the
18-40 GHz region and by ab-initio anharmonic force field calculations. For
analyzing the emission lines of CHCHCN species detected in Orion-KL we used
the excitation and radiative transfer code (MADEX) at LTE conditions. The
rotational transitions of the ground state of this molecule emerge from four
cloud components of hot core nature which trace the physical and chemical
conditions of high mass star forming regions in the Orion-KL Nebula. The total
column density of CHCHCN in the ground state is (3.00.9)x10
cm. We report on the first interstellar detection of transitions in the
v10=1/(v11=1,v15=1) dyad in space, and in the v11=2 and v11=3 states in
Orion-KL. The lowest energy vibrationally excited states of vinyl cyanide such
as v11=1 (at 328.5 K), v15=1 (at 478.6 K), v11=2 (at 657.8 K), the
v10=1/(v11=1,v15=1) dyad (at 806.4/809.9 K), and v11=3 (at 987.9 K) are
populated under warm and dense conditions, so they probe the hottest parts of
the Orion-KL source. Column density and rotational and vibrational temperatures
for CHCHCN in their ground and excited states, as well as for the
isotopologues, have been constrained by means of a sample of more than 1000
lines in this survey. Moreover, we present the detection of methyl isocyanide
(CHNC) for the first time in Orion-KL and a tentative detection of vinyl
isocyanide (CHCHNC) and give column density ratios between the cyanide and
isocyanide isomers.Comment: 46 pages, 22 figures, 14 tables, 9 online table
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