National University of La Plata

About: National University of La Plata is a education organization based out in La Plata, Argentina. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 12993 authors who have published 30013 publications receiving 495118 citations. The organization is also known as: UNLP & Universidad Nacional de La Plata.

iPTF13bvn: the first evidence of a binary progenitor for a type Ib supernova

Abstract: The recent detection in archival Hubble Space Telescope images of an object at the location of supernova (SN) iPTF13bvn may represent the first direct evidence of the progenitor of a Type Ib SN. The object's photometry was found to be compatible with a Wolf-Rayet pre-SN star mass of ≈11 M ☉. However, based on hydrodynamical models, we show that the progenitor had a pre-SN mass of ≈3.5 M ☉ and that it could not be larger than ≈8 M ☉. We propose an interacting binary system as the SN progenitor and perform evolutionary calculations that are able to self-consistently explain the light curve shape, the absence of hydrogen, and the pre-SN photometry. We further discuss the range of allowed binary systems and predict that the remaining companion is a luminous O-type star of significantly lower flux in the optical than the pre-SN object. A future detection of such a star may be possible and would provide the first robust identification of a progenitor system for a Type Ib SN.

Mesoporous films and polymer brushes helping each other to modulate ionic transport in nanoconfined environments. An interesting example of synergism in functional hybrid assemblies.

Abstract: Rational design of fully synthetic platforms displaying active control over ionic transport in close resemblance to biological systems represents an ongoing challenge in molecular materials science. Here, we demonstrate that the synergism arising from the chemistries involved in mesoporous films and polymer brushes is a key enabler to next-generation “smart” nanofilters capable of mimicking the gating functions of specific biological channels. Hybrid functional assemblies constituted of mesoporous silica films modified with polyzwitterionic brushes are able to discriminate and gate the transport of cations while the passage of anionic species is precluded. The synthetic membranes behave as proton-gated cation-selective platforms mimicking the functioning of acid-sensing ion channels encountered in the neurons of the central nervous system. We believe that this experimental evidence will stimulate further multidisciplinary work across the boundaries of materials chemistry to attain new functional nanostruc...

Isolation and analysis of endophytic microorganisms in wheat (Triticum aestivum L.) leaves

Abstract: The present investigation was undertaken in order to select the surface-sterilization technique most efficient for eliminating epiphytes, to document the spectrum of endophytes of healthy leaves from three wheat cultivars in Buenos Aires Province (Argentina) and to determine their infection frequencies at three growth stages. Surface-sterilization with undiluted commercial solution of sodium hypochlorite was reaffirmed as adequate for removing epiphytes on wheat leaves. From the 450 wheat leaf segments incubated, three bacterial isolates and 130 fungal isolates were obtained. From all the isolates, 19 fungal species were identified. Bacterial isolates were characterized as Bacillus sp. There were significant differences between microorganisms, stages of growth, and stages × microorganisms interaction. Differences between cultivars, stages × cultivars, microorganisms × cultivars and for the triple interaction were not significant. Frequency of microorganisms isolated increased with crop age, but it was statistically similar for the three wheat cultivars tested (Klein Centauro, Klein Dragon and Buck Ombu). Rhodotorula rubra, Alternaria alternata, Cladosporium herbarum and Epicoccum nigrum were isolated in the highest frequency. The other microorganisms were present at intermediate or low values. The species isolated may be assigned to three groups: (a) well-known and economically important pathogens of wheat, (b) commonly abundant phylloplane fungi considered to be primary saprobic and minor pathogens and (c) species occasionally present in wheat.

A high sensitivity HI survey of the sky at δ ≤ -25 ° . Final data release

Abstract: We present the final data release of the high sensitivity λ 21-cm neutral hydrogen survey of the sky south of δ ≤− 25 ◦ . A total of 50 980 positions lying on a galactic coordinate grid with points spaced by (∆l, ∆b) = (0. ◦ 5/cos b, 0. 5) were observed with the 30-m dish of the Instituto Argentino de Radioastronomia (IAR). The angular resolution of the survey is HPBW = 0. ◦ 5 and the velocity coverage spans the interval −450 km s −1 to +400 km s −1 (LSR). The velocity resolution is 1.27 km s −1 and the final rms noise of the entire database is 0.07 K. The data are corrected for stray radiation and converted to brightness temperatures.

Renormalization of the inverse square potential

Abstract: The quantum-mechanical $D$-dimensional inverse square potential is analyzed using field-theoretic renormalization techniques. A solution is presented for both the bound-state and scattering sectors of the theory using cutoff and dimensional regularization. In the renormalized version of the theory, there is a strong-coupling regime where quantum-mechanical breaking of scale symmetry takes place through dimensional transmutation, with the creation of a single bound state and of an energy-dependent $s$-wave scattering matrix element.