5 research outputs found
Impacts of saltwater intrusion on soil nematodes community in alluvial and acid sulfate soils in paddy rice fields in the Vietnamese Mekong Delta
© 2020 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. https://creativecommons.org/licenses/by-nc-nd/4.0/Saltwater intrusion is a potential risk damaging crop diversity and productivity due to degraded soil physicochemical properties. However, little is known about how salinity affects the structure and function of soil nematodes community in intensive rice cultivated area. This study aimed (1) to assess the impacts of saltwater intrusion on the nematode community in alluvial and acid sulfate soils; and (2) to evaluate its relation with soil conditions. Saltwater intrusion reduced the abundance of both free-living nematodes (FLN) and plant-parasitic nematodes (dominated by Hirschmanniella) in soils. FLN community was different among sites with different physicochemical properties. The omnivorous genera Aporcelaimellus and Thornenema were only found in non-salt-affected alluvial soil, whilst Mesodorylaimus was dominant in salt-affected acid sulfate soil, suggesting that this genus might be tolerant to higher EC and soluble Na+, K+, Ca2+. The bacterivorous nematodes (dominant taxa Chronogaster, Rhabdolaimus) were dominant in both non-salt affected and salt-affected alluvial soils, which accounted for 48% and 40%, respectively, whilst it accounted for 21% in salt-affected acid sulfate soil. The abundance of fungivorous nematodes (Aphelenchoides, Ditylenchus, Filenchus) were greater in salt-affected alluvial soil in contrast to the other treatments, suggesting that these might be tolerant to salinity and low pH. Saltwater intrusion reduced biological diversity (Margalef, Shannon-Wiener, and Hill’s indices), maturity index (∑MI, MI25), and clearly affected functional guilds of nematode community, especially c-p 5 group was reduced in both salt-affected soils. This study suggests that saltwater intrusion showed a potential risk in the degradation of soil properties, as indicated by the altered nematode community, trophic structure, functional guilds and their ecological indices in paddy fields.Peer reviewedFinal Published versio
Instability, Intermixing and Electronic Structure at the Epitaxial LaAlO3/SrTiO3(001) Heterojunction
The question of stability against diffusional mixing at the prototypical
LaAlO3/SrTiO3(001) interface is explored using a multi-faceted experimental and
theoretical approach. We combine analytical methods with a range of
sensitivities to elemental concentrations and spatial separations to
investigate interfaces grown using on-axis pulsed laser deposition. We also
employ computational modeling based on the density function theory as well as
classical force fields to explore the energetic stability of a wide variety of
intermixed atomic configurations relative to the idealized, atomically abrupt
model. Statistical analysis of the calculated energies for the various
configurations is used to elucidate the relative thermodynamic stability of
intermixed and abrupt configurations. We find that on both experimental and
theoretical fronts, the tendency toward intermixing is very strong. We have
also measured and calculated key electronic properties such as the presence of
electric fields and the value of the valence band discontinuity at the
interface. We find no measurable electric field in either the LaAlO3 or SrTiO3,
and that the valence band offset is near zero, partitioning the band
discontinuity almost entirely to the conduction band edge. Moreover, we find
that it is not possible to account for these electronic properties
theoretically without including extensive intermixing in our physical model of
the interface. The atomic configurations which give the greatest electrostatic
stability are those that eliminate the interface dipole by intermixing, calling
into question the conventional explanation for conductivity at this interface -
electronic reconstruction. Rather, evidence is presented for La indiffusion and
doping of the SrTiO3 below the interface as being the cause of the observed
conductivity
Decentralized ciphertext-policy attribute-based encryption schemes for lightweight devices
In a traditional attribute-based encryption (ABE) system, there is only one central authority who generates and hence knows the secret keys of all users, this problem is known as the key escrow problem. An ABE scheme which can deal with the aforementioned problem is so-called a decentralized (or multi-authority) ABE scheme. There have been several efforts to propose decentralized ABE schemes in the literature, and these schemes can enjoy some interesting properties such as fine-grained access control and full security. However, all of them suffer from two main weaknesses that are large secret key size and slow decryption time. These weaknesses are obviously not desirable for lightweight device applications such as Internet of Things applications. In this paper, we propose two decentralized ciphertext-policy attribute-based encryption schemes. Our proposed schemes have some nice properties such as constant-size secret key, fast decryption, optimized ciphertext size and fine-grained access control. Our schemes, as a result, could be seen as a solution for lightweight device applications. For completeness, we implement our schemes and give some concrete benchmarks. - 2019 Elsevier B.V.This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 102.01-2018.301 .Scopu