2,306 research outputs found
New locality record of Psomophis genimaculatus (Squamata, Dipsadidae) in Argentina
Se presenta un nuevo registro de Psomophis genimaculatus (Boettger, 1885). Esta serpiente está categorizada como insuficientemente conocida en Argentina. Se colectó un espécimen en Campo Largo, Provincia de Chaco, Argentina, cubriendo un vacío en el área de distribución de la especie entre los puntos extremos de su rango de distribución en Argentina
On singular perturbations of flexible and variable-speed wind turbines
A model for the mechanical dynamics of a wind turbine is developed, which is the composition of three physical mechanisms:
flexion, torsion, and rotational dynamics. A first contribution is the identification of the essential physical parameters that provide
a time-scale separation of these three mechanisms. Under the assumption of singular perturbations the time-scale separation
allows to work with a reduced model of order one. This reduction has been essential for the control of this system allowing to
control designers to take into account only the reduced-order model. A second contribution consists in employing a measurement
of the fore-aft nacelle acceleration with the reduced model, together with a Kalman filter to estimate the flexible DOFs of the system
(tower and average blade deflection). The successful approach is tested on high-order nonlinear aeroelastic simulator (FAST)
Deep excursion beyond the proton dripline. I. Argon and chlorine isotope chains
The proton-unbound argon and chlorine isotopes have been studied by measuring trajectories
of their decay-in-flight products by using a tracking technique with micro-strip detectors. The
proton (1p) and two-proton (2p) emission processes have been detected in the measured angular
correlations “heavy-fragment”+p and “heavy-fragment”+p+p, respectively. The ground states of
the previously unknown isotopes 30Cl and 28Cl have been observed for the first time, providing the
1p separation energies Sp of −0.48(2) and −1.60(8) MeV, respectively. The relevant systematics of
1p and 2p separation energies have been studied theoretically in the core+p and core+p+p cluster
models. The first-time observed excited states of 31Ar allow to infer the 2p-separation energy S2p
of 6(34) keV for its ground state. The first-time observed state in 29Ar with S2p = −5.50(18) MeV
can be identified either as a ground or an excited state according to different systematics.Helmholtz Association grant IK-RU-002Helmholtz International Center for FAIR HIC for FAIRRussian Science Foundation grant No. 17-12-01367Polish National Science Center Contract No. UMO- 2015/17/B/ST2/00581Polish Ministry of Science and Higher Education Grant No. 0079/DIA/2014/43, Grant DiamentowyHelmholtz- CAS Joint Research Group grant HCJRG-10
The Blackspot seabream Spanish target fishery of the Strait of Gibraltar: updating the available information
This paper includes the available information of the Blackspot seabream
(Pagellus bogaraveo) Spanish target fishery in the Strait of Gibraltar updating
the documents presented in previous years with the information from 2019. So,
data about landings, fishing effort, CPUEs and landings length frequencies are
presented to its discussion within the 2020 WGDEEP
Deep excursion beyond the proton dripline. II. Toward the limits of existence of nuclear structure
Prospects of experimental studies of argon and chlorine isotopes located far beyond the proton dripline are studied by using systematics and cluster models. The deviations from the widespread systematics observed in
28
,
29
Cl
and
29
,
30
Ar
have been theoretically substantiated, and analogous deviations have been predicted for the lighter chlorine and argon isotopes. The limits of nuclear structure existence are predicted for Ar and Cl isotopic chains, with
26
Ar
and
25
Cl
found to be the lightest sufficiently long-living nuclear systems. By simultaneous measurements of protons and
γ
rays following decays of such systems as well as their
β
-delayed emission, an interesting synergy effect may be achieved, which is demonstrated by the example of
30
Cl
and
31
Ar
ground-state studies. Such a synergy effect may be provided by the new EXPERT setup (EXotic Particle Emission and Radioactivity by Tracking) being operated inside the fragment separator and spectrometer facility at GSI, Darmstadt.Helmholtz Association de Alemania. IK-RU-002Russian Science Foundation. 17-12-01367Polish National Science Center. UMO2015/17/B/ST2/00581Polish Ministry of Science and Higher Education. 0079/DIA/2014/43Helmholtz- CAS Joint Research Group de Alemania. HCJRG-108Ministerio de Educación y Ciencia, España. FPA2016-77689-C2-1-RMinistry of Education, Youth and Sports de la República Checa. LTT17003 y LM201504
The NUMEN Project @ LNS: Status and Perspectives
The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. Particular attention is given to the (18O,18Ne) and (20Ne,20O) reactions as tools for β+β+ and β-β- decays, respectively. First evidence about the possibility to get quantitative information about NME from experiments is found for both kind of reactions. In the experiments, performed at INFN -Laboratory Nazionali del Sud (LNS) in Catania, the beams are accelerated by the Superconducting Cyclotron (CS) and the reaction products are detected the MAGNEX magnetic spectrometer. The measured cross sections are challengingly low, limiting the present exploration to few selected isotopes of interest in the context of typically low-yield experimental runs. A major upgrade of the LNS facility is foreseen in order to increase the experimental yield of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest. Frontiers technologies are going to be developed, to this purpose, for the accelerator and the detection systems. In parallel, advanced theoretical models will be developed in order to extract the nuclear structure information from the measured cross sections
Spectroscopy of excited states of unbound nuclei 30 Ar and 29 Cl
Several states of proton-unbound isotopes
30
Ar
and
29
Cl
were investigated by measuring their in-flight decay products,
28
S
+ proton + proton and
28
S
+ proton, respectively. A refined analysis of
28
S
-proton angular correlations indicates that the ground state of
30
Ar
is located at
2
.
45
+
0.05
−
0.10
MeV above the two-proton emission threshold. The investigation of the decay mechanism of the
30
Ar
ground state demonstrates that it has the transition dynamics. In the “transitional” region, the correlation patterns of the decay products present a surprisingly strong sensitivity to the two-proton decay energy of the
30
Ar
ground state and the one-proton decay energy as well as the one-proton decay width of the
29
Cl
ground state. The comparison of the experimental
28
S
-proton angular correlations with those resulting from Monte Carlo simulations of the detector response illustrates that other observed
30
Ar
excited states decay by sequential emission of protons via intermediate resonances in
29
Cl
. Based on the findings, the decay schemes of the observed states in
30
Ar
and
29
Cl
were constructed. For calibration purposes and for checking the performance of the experimental setup, decays of the previously known states of a two-proton emitter
19
Mg
were remeasured. Evidences for one new excited state in
19
Mg
and two unknown states in
18
Na
were found.Helmholtz International Center for FAIR de Alemania (HIC for FAIR) IK-RU-002Russian Ministry of Education and Science. NSh-932.2014.2Russian Science Foundation. 17-12-01367Polish National Science Center. UMO-2011/01/B/ST2/01943Polish Ministry of Science and Higher Education. 0079/DIA/2014/43HelmholtzCAS Joint Research Group de Alemania. HCJRG-108Ministerio de Ciencia, Innovación y Universidades de España (MICINN). FPA2009-0884
Elastic Scattering for the 11Be+64Zn System Close to the Coulomb Barrier
The quasi-elastic scattering angular distribution of the collision 11Be + 64Zn was measured and compared with the elastic scattering angular distribution for its core, the 10Be nucleus on the same target. Optical model and continuum-discretized coupled-channel calculations of the 11Be+64Zn reaction were performed in order to interpret the effect of coupling with the break-up channels on the measured cross-sections
Interaction of 8 He with 208Pb at near-barrier energies: 4 He and 6 He production
Spanish Ministry of Economy and Competitiveness-FPA-2010-22131-CO2-01 (FINURA) y FPA2013-47327-C2-1-RMinistry of Science and Higher Education of Poland-N202 033637National Science Centre of Poland-2013/08/M/ST2/00257 (LEA-COPIGAL) y 2014/14/M/ST2/00738 (COPIN-INFN Collaboration)European Science Foundation-EUI2009-04163432 (EUROGENESIS
Variant surface glycoproteins from Venezuelan trypanosome isolates are recognized by sera from animals infected with either Trypanosoma evansi or Trypanosoma vivax
AbstractSalivarian trypanosomes sequentially express only one variant surface glycoprotein (VSG) on their cell surface from a large repertoire of VSG genes. Seven cryopreserved animal trypanosome isolates known as TeAp-ElFrio01, TEVA1 (or TeAp-N/D1), TeGu-N/D1, TeAp-Mantecal01, TeGu-TerecayTrino, TeGu-Terecay03 and TeGu-Terecay323, which had been isolated from different hosts identified in several geographical areas of Venezuela were expanded using adult albino rats. Soluble forms of predominant VSGs expressed during the early infection stages were purified and corresponded to concanavalin A-binding proteins with molecular masses of 48–67kDa by sodium dodecyl sulfate-polyacrylamide gel electropohoresis, and pI values between 6.1 and 7.5. The biochemical characterization of all purified soluble VSGs revealed that they were dimers in their native form and represented different gene products. Sequencing of some of these proteins yielded peptides homologous to VSGs from Trypanosoma (Trypanozoon) brucei and Trypanosoma (Trypanozoon) evansi and established that they most likely are mosaics generated by homologous recombination. Western blot analysis showed that all purified VSGs were cross-reacting antigens that were recognized by sera from animals infected with either T. evansi or Trypanosoma (Dutonella) vivax. The VSG glycosyl-phosphatidylinositol cross-reacting determinant epitope was only partially responsible for the cross-reactivity of the purified proteins, and antibodies appeared to recognize cross-reacting conformational epitopes from the various soluble VSGs. ELISA experiments were performed using infected bovine sera collected from cattle in a Venezuelan trypanosome-endemic area. In particular, soluble VSGs from two trypanosome isolates, TeGu-N/D1 and TeGu-TeracayTrino, were recognized by 93.38% and 73.55% of naturally T. vivax-infected bovine sera, respectively. However, approximately 70% of the sera samples did not recognize all seven purified proteins. Hence, the use of a combination of various VSGs for the diagnosis of animal trypanosomosis is recommended
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