489 research outputs found
Spectroscopy of high-lying resonances in 9 Be by the measurement of ( p , p ), ( p , d ), and ( p , α ) reactions with a radioactive 8 Li beam
We measured the
8
Li
(
p
,
p
)
8
Li
,
8
Li
(
p
,
d
)
7
Li
, and
8
Li
(
p
,
α
)
5
He
reactions at low energies using the thick target inverse kinematics method, with a polyethylene
[
CH
2
]
n
target and a radioactive
8
Li
beam available at the Radioactive Ion Beams in Brazil facility of São Paulo. By measuring simultaneously several reaction channels
(
p
,
p
)
,
(
p
,
d
)
, and
(
p
,
α
)
, the still uncertain high-lying resonances of
9
Be
, close to the proton threshold, can be studied and their parameters, such as energy, width, and spin parity can be more reliably determined. The experimental excitation functions of the reactions
8
Li
(
p
,
p
)
8
Li
,
8
Li
(
p
,
d
)
7
Li
, and
8
Li
(
p
,
α
)
5
He
were analyzed using the
R
-matrix theory, which allows us to infer the properties of the resonances. Multichannel
R
-matrix analysis provides evidence for a significant clustering in the
(
p
,
d
)
channel. The experimental data and the multichannel
R
-matrix analysis will be presented.Fundação de Amparo à Pesquisa do Estado de São Paulo. Brasil. (FAPESP) 2011/15904-7, 2013/22100-7 y 2016/21434-7VI Plan Propio de Investigación de la Universidad de Sevilla. España. (2017–2018
Copper-containing mesoporous bioactive glass promotes angiogenesis in an in vivo zebrafish model
The osteogenic and angiogenic responses of organisms to the ionic products of degradation of bioactive glasses (BGs) are being intensively investigated. The promotion of angiogenesis by copper (Cu) has been known for more than three decades. This element can be incorporated to delivery carriers, such as BGs, and the materials used in biological assays. In this work, Cu-containing mesoporous bioactive glass (MBG) in the SiO2-CaO-P2O5 compositional system was prepared incorporating 5% mol Cu (MBG-5Cu) by replacement of the corresponding amount of Ca. The biological effects of the ionic products of MBG
biodegradation were evaluated on a well-known endothelial cell line, the bovine aorta endothelial cells (BAEC), as well as in an in vivo zebrafish (Danio rerio) embryo assay. The results suggest that ionic products of both MBG (Cu free) and MBG-5Cu materials promote angiogenesis. In vitro cell cultures show that the ionic dissolution products of these materials are not toxic and promote BAEC viability and migration.
In addition, the in vivo assay indicates that both exposition and microinjection of zebrafish embryos with Cu free MBG material increase vessel number and thickness of the subintestinal venous plexus (SIVP), whereas assays using MBG-5Cu enhance this effect.The authors gratefully acknowledge the financial support provided by the Andalusian Ministry of Economy, Science and Innovation
(Proyectos Excelencia Grants no. P10-CTS-6681 and no. P12-CTS-1507) and Spanish Ministry of Economy and Competitivity
(BIO2014-56092-R). LBRS acknowledges the CONACYT-Mexico Fellowship PhD Program
The nonlinear Schroedinger equation for the delta-comb potential: quasi-classical chaos and bifurcations of periodic stationary solutions
The nonlinear Schroedinger equation is studied for a periodic sequence of
delta-potentials (a delta-comb) or narrow Gaussian potentials. For the
delta-comb the time-independent nonlinear Schroedinger equation can be solved
analytically in terms of Jacobi elliptic functions and thus provides useful
insight into the features of nonlinear stationary states of periodic
potentials. Phenomena well-known from classical chaos are found, such as a
bifurcation of periodic stationary states and a transition to spatial chaos.
The relation of new features of nonlinear Bloch bands, such as looped and
period doubled bands, are analyzed in detail. An analytic expression for the
critical nonlinearity for the emergence of looped bands is derived. The results
for the delta-comb are generalized to a more realistic potential consisting of
a periodic sequence of narrow Gaussian peaks and the dynamical stability of
periodic solutions in a Gaussian comb is discussed.Comment: Enhanced and revised version, to appear in J. Nonlin. Math. Phy
The QUIJOTE experiment: project overview and first results
QUIJOTE (Q-U-I JOint TEnerife) is a new polarimeter aimed to characterize the
polarization of the Cosmic Microwave Background and other Galactic and
extragalactic signals at medium and large angular scales in the frequency range
10-40 GHz. The multi-frequency (10-20~GHz) instrument, mounted on the first
QUIJOTE telescope, saw first light on November 2012 from the Teide Observatory
(2400~m a.s.l). During 2014 the second telescope has been installed at this
observatory. A second instrument at 30~GHz will be ready for commissioning at
this telescope during summer 2015, and a third additional instrument at 40~GHz
is now being developed. These instruments will have nominal sensitivities to
detect the B-mode polarization due to the primordial gravitational-wave
component if the tensor-to-scalar ratio is larger than r=0.05.Comment: To appear in "Highlights of Spanish Astrophysics VIII", Proceedings
of the XI Scientific Meeting of the Spanish Astronomical Society, Teruel,
Spain (2014
A new species of cosmocercoides (Nematoda; cosmocercidae) and other helminths in leptodactylus latrans (anura; leptodactylidae) from Argentina
Cosmocercoides latrans n. sp. (Cosmocercidae) from the small intestine of Leptodactylus latrans (Anura: Leptodactylidae) from Northeastern Province of Buenos Aires, Argentina is described. The new species can be distinguished from their congeners by a combination of the characters, among which stands out the number of rosette papillae, the lack of gubernaculum and the presence of lateral alae in both sexes. There are over 20 species in the genus Cosmocercoides, and Cosmocercoides latrans n. sp. represents the third species from the Neotropical realm and the second for Argentina. Additionally, seven previously known taxa are reported; Pseudoacanthocephalus cf. lutzi, Catadiscus uruguayensis, Rauschiella palmipedis, Aplectana hylambatis, Cosmocerca parva, Schrankiana sp. and Rhabdias elegans; providing literature records and information on distribution and host-parasite relationships.Fil: Draghi, Regina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Drago, Fabiana Beatriz. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Lunaschi, Lía Inés. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentin
Elementos conceptuales y metodológicos para la evaluación de impactos ambientales acumulativos (eiaac) en bosques subtropicales : el caso del este de salta, argentina
163-178Northern Argentina experienced an unprecedented deforestation rate of xerophitic forests as a consequence of agricultural expansion. In the Province of Salta, 26 percent of the forest were removed between 1977 and 2008. At the end of 2007, just before the No. 26331 Law of Native Forest Protection was voted by the Congress, the highest annual rate of deforestation was registered, reaching a value of 2.1 percent. Regarding this situation, indigenous people of Eastern Salta along with the "criollos" (local small ranchers) appealed to the National Supreme Court of Justice for legal protection. The Court requested the province to elaborate a Cumulative Environmental Effects Assessment (CEEA) regarding the process of logging and deforestation in four departments of Salta Province (San Martín, Rivadavia, Santa Victoria, and Orán). The aim of this work is to present a conceptual framework to conduct a CEEA in eastern Salta and to present the evidences and existing methodologies to characterize the impacts of deforestation. The conceptual framework suggested depends on the quantitative characterization of the changes in the provision level of key ecosystem services as a function of the stress and/or disturbance level (in this case deforestation). Based on the literature and our own data, the effects of deforestation on four key ecosystem services have been assessed: C dynamics, energy balance and greenhouse gases emissions, water dynamics and landscape structure. Deforestation produced emissions of 2000 t of CH 4, 200 t of N 2O, above 20 Gg of C/year, a 1.1 watt/m2 reduction in reflected radiation and 4400 TJ radiative energy emissions caused by deforestation fires, increases in the risk of soil salinization and landscape fragmentation. Considering these aspects of the structure and functioning of the ecosystems provides objective elements to evaluate management alternatives and to elaborate monitoring programmes. To consider such management and monitoring alternatives arises technical challenges but also institutional and political ones
QUIJOTE-CMB experiment: a technical overview
The QUIJOTE-CMB experiment (Q-U-I JOint TEnerife CMB experiment) is an ambitious project to obtain polarization measurements of the sky microwave emission in the 10 to 47 GHz range. With this aim, a pair of 2,5m telescopes and three instruments are being sited at the Teide Observatory, in Tenerife (Canary Islands, Spain). The first telescope and the first instrument (the MFI: Multi Frequency Instrument) are both already operating in the band from 10 to 20 GHz, since November 2012. The second telescope and the second instrument (TGI: Thirty GHz instrument) is planned to be in commissioning by the end of summer 2014, covering the range of 26 to 36 GHz. After that, a third instrument named FGI (Forty GHz instrument) will be designed and manufactured to complete the sky survey in the frequency range from 37 to 47 GHz. In this paper we present an overview of the whole project current status, from the technical point of view
Indicators of river system hydromorphological character and dynamics: understanding current conditions and guiding sustainable river management
The work leading to this paper received funding from the EU’s FP7 programme under Grant Agreement No. 282656 (REFORM). The Indicators were developed within the context of REFORM deliverable D2.1, therefore all partners involved in this deliverable contributed to some extent to their discussion and development
The QUIJOTE TGI
The QUIJOTE TGI instrument is currently being assembled and tested at the IAC in Spain. The TGI is a 31 pixel 26-36 GHz polarimeter array designed to be mounted at the focus of the second QUIJOTE telescope. This follows a first telescope and multi-frequency instrument that have now been observing almost 2 years. The polarimeter design is based on the QUIET polarimeter scheme but with the addition of an extra 90º phase switch which allows for quasiinstantaneous complete QUI measurements through each detector. The advantage of this is a reduction in the systematics associated with differencing two independent radiometer channels. The polarimeters are split into a cold front end and a warm back end. The back end is a highly integrated design by engineers at DICOM. It is also sufficiently modular for testing purposes. In this presentation the high quality wide band components used in the optical design (also designed in DICOM) are presented as well as the novel cryogenic modular design. Each polarimeter chain is accessible individually and can be removed from the cryostat and replaced without having to move the remaining pixels. The optical components work over the complete Ka band showing excellent performance. Results from the sub unit measurements are presented and also a description of the novel calibration technique that allows for bandpass measurement and polar alignment. Terrestrial Calibration for this instrument is very important and will be carried out at three points in the commissioning phase: in the laboratory, at the telescope site and finally a reduce set of calibrations will be carried out on the telescope before measurements of extraterrestrial sources begin. The telescope pointing model is known to be more precise than the expected calibration precision so no further significant error will be added through the telescope optics. The integrated back-end components are presented showing the overall arrangement for mounting on the cryostat. Many of the microwave circuits are in-house designs with performances that go beyond commercially available products. Individual component performance is be presented showing for each of the sub modules
QUIJOTE Experiment: status of telescopes and instrumentation
The QUIJOTE Experiment (Q-U-I JOint TEnerife) is a combined operation of two telescopes and three instruments working in the microwave band to measure the polarization of the Cosmic Microwave Background (CMB) from the northern hemisphere, at medium and large angular scales. The experiment is located at the Teide Observatory in Tenerife, one of the seven Canary Islands (Spain). The project is a consortium maintained by several institutions: the Instituto de Astrofísica de Canarias (IAC), the Instituto de Física de Cantabria (IFCA), the Communications Engineering Department (DICOM) at Universidad de Cantabria, and the Universities of Manchester and Cambridge. The consortium is led by the IAC
- …