118 research outputs found
The Current Adoption of Dry-Direct Seeding Rice (DDSR) in Thailand and Lessons Learned for Mekong River Delta of Vietnam
The paper documents the joint study trip, organized by CCAFS Southeast Asia for Vietnamese rice researchers, extension workers, as well as local decision makers, to visit Thailand in April 2018. The goal of the study trip was to observe and learn the experience of Thai farmers on the large-scale adoption process of dry-direct seeding rice (DDSR), a viable alternative to address regional scarcity of fresh water in irrigation caused by the drought and salinity intrusion in the Mekong River Delta
Semilinear elliptic Schr\"odinger equations with singular potentials and absorption terms
Let () be a bounded domain and
be a compact, submanifold without boundary, of
dimension with . Put in
, where and
is a parameter. We investigate the boundary value problem (P) in with condition on , where is a nondecreasing,
continuous function, and and are positive measures. The complex
interplay between the competing effects of the inverse-square potential
, the absorption term and the measure data
discloses different scenarios in which problem (P) is solvable. We provide
sharp conditions on the growth of for the existence of solutions. When
is a power function, namely with , we show that problem
(P) admits several critical exponents in the sense that singular solutions
exist in the subcritical cases (i.e. is smaller than a critical exponent)
and singularities are removable in the supercritical cases (i.e. is greater
than a critical exponent). Finally, we establish various necessary and
sufficient conditions expressed in terms of appropriate capacities for the
solvability of (P).Comment: 40 page
Semilinear elliptic equations involving power nonlinearities and hardy potentials with boundary singularities
Let () be a bounded domain and
be a compact submanifold without
boundary, of dimension , . We assume that
if and if . Denote
and put where is a parameter. In this paper, we study boundary
value problems for equations in with
prescribed condition on , where and is a
given measure on . The nonlinearity is referred
to as \textit{absorption} or \textit{source} depending whether the plus sign or
minus sign appears. The distinctive feature of the problems is characterized by
the interplay between the concentration of , the type of nonlinearity,
the exponent and the parameter . The absorption case and the source
case are sharply different in several aspects and hence require completely
different approaches. In each case, we establish various necessary and
sufficient conditions expressed in terms of appropriate capacities. In
comparison with related works in the literature, by employing a fine analysis,
we are able to treat the supercritical ranges for the exponent , and the
critical case for the parameter , which justifies the novelty of our
paper.Comment: 45 pages. arXiv admin note: text overlap with arXiv:2203.0126
The influence of foundation mass on dynamic response of track-vehicle interaction
The influence of foundation mass on the dynamic response of track-vehicle interaction is studied in this paper. The moving vehicle is modeled as a two-axle mass-spring-damper four-degrees-of-freedom system. A new dynamic foundation model, called "Dynamic foundation model" including linear elastic spring, shear layer, viscous damping and foundation mass parameter, is used to analyze the dynamic response of the track-vehicle interaction. The railway track on the new dynamic foundation model subjected to a moving vehicle is regarded as an integrated system. By means of the finite element method and dynamic balance principle, the governing equation of motion for railway track-vehicle-foundation interaction is derived and solved by the step-by-step integration method. The accuracy of the algorithm is verified by comparing the numerical results with the other numerical results in the literature. The influence of foundation mass parameter on the dynamic response of railway track-vehicle interaction is investigated. The numerical results show that with the new dynamic foundation model the foundation mass effects more significantly on the dynamic response of track-vehicle interaction. The study shows that the new dynamic foundation model describes the true behavior of soil in the analysis of dynamic response of structures on the foundation
Identifying QTLs Associated and Marker-Assisted Selection for Salinity Tolerance at the Seedling, Vegetative and Reproductive Stages in Rice (Oryza Sativa L.)
Salinity affects rice growth in all growth stages, with the seedling and reproductive stages being the most sensitive. Genetically improving salt tolerance of rice is an important objective of rice breeding programs. Hence, mapping quantitative trait loci (QTL) will be useful for marker-assisted selection in rice breeding programs. An advanced backcross population (BC2F2) was developed with the parents included OM5629 as a donor of salt tolerance and OM7347 as a recurrent parent with good quality traits and drought tolerance. Molecular markers associated with both qualitative and quantitative trait loci (QTL) salt tolerance were identified by using 416 polymorphic SSR markers. QTLs, associated with stress tolerance at EC = 15 dS/m at seedling stage, detected from the BC2F2 population of OM7347/OM5629, were located on chromosomes 1 and 3. Three QTLs were identified at the intervals of RM3252-S1-1 - RM10694, RM3740-RM5336 and RM11125-RM9 with genetic distance of 4.4, 4.5 and 18 cM on chromosome 1, respectively. Two QTLs at the intervals of RM3867-RM6959 and RM6876-RM4425 with genetic distance of 4.5 and 18.0 cM on chromosome 3, respectively. One QTL on chromosome 5 was detected at the interval of RM874 - RM10359, it was associated with salt stress tolerance under EC = 8dS/m at vegetative stage. Three QTLs at the regions of RM1324-RM2412, RM1185-RM24, and RM1282-RM2560 on chromosome 1, and one QTL of RM453-RM511 on chromosome 12, were related to salt tolerance under EC = 8dS/m at reproductive stage. Two tightly linked markers as RM3252-S1-1 and RM3867, were exhibited their effectiveness in identification of salt tolerance genotypes in BC3F6 population of OMCS2000/ Pokkali. The identification of new QTLs associated with salt tolerance will provide important information for the functional analysis of rice salinity stress
Effects of foundation mass on dynamic responses of beams subjected to moving oscillators
This paper aims at the effects of foundation mass on the dynamic responses of beams subjected to moving oscillators. To achieve this aim, experiments were performed for a beam resting on the foundation considering effects of the foundation model including linear elastic spring, shear layer, viscous damping. In addition, special effects of mass density of foundation during vibration were established to obtain the characteristic parameter of the influence of foundation mass based on natural circular frequency of the structure system determined from FFT plots of the time history of acceleration data. Furthermore, the experimental parameters were used to analyze the influence of the foundation mass on the dynamic response of the beam subjected to moving oscillator. Comparisons between experimental and simulated results showed that the foundation mass showed significant effects on the dynamic characteristic response of the beam system. It increased the general vibrating mass of the structure system. Hence, it decreased of the natural frequency of the structural system and caused a significant increase on the dynamic response of the beam when compared with the case without considering the foundation mass. Finally, the relationships between the foundation properties and the parameters of foundation mass were derived and discussed
Presence of e-EDCs in surface water and effluents of pollution sources in Sai Gon and Dong Nai river basin
© 2016 This study aimed to assess the presence of estrogenic endocrine disrupting compounds (e-EDCs) including estriol, bisphenol A (BPA), atrazine (ATZ), octylphenol, octylphenol diethoxylate, octylphenol triethoxylate, nonylphenol, Nonylphenol triethoxylate (NPE3), nonylphenol diethoxylate (NPE2) and 17β-estradiol in: (i) Sai Gon and Dong Nai river waters which have been major raw water sources for drinking water supply for Ho Chi Minh City (HCMC) and neighbouring provinces, and (ii) water pollution sources located in their catchment basin. NPE3 and NPE2 were detected in most of the surface water samples. Concentrations of NPE3 were in a range of less than 5.9–235 ng L−1, whereas BPA was detected at significantly high concentrations in the dry season in canals in HCMC. In the upstream of Sai Gon and Dong Nai Rivers, ATZ concentrations were observed at water intake of water treatment plants served for HCMC water supply system. Similarly, high potential risk of NPE2 and NPE3 contamination at Phu Cuong Bridge near Hoa Phu water intake was identified. The significant correlation between NPE2, dissolved organic carbon and total nitrogen was found. Estrogenic equivalent or estrogenic activity of Sai Gon and Dong Nai Rivers was lower than those of the previous studies. Compared with other studies, e-EDCs of pollution in Sai Gon river basin were relatively low
Characterisation of the RNA Virome of Nine Ochlerotatus Species in Finland
RNA viromes of nine commonly encountered Ochlerotatus mosquito species collected around Finland in 2015 and 2017 were studied using next-generation sequencing. Mosquito homogenates were sequenced from 91 pools comprising 16–60 morphologically identified adult females of Oc. cantans, Oc. caspius, Oc. communis, Oc. diantaeus, Oc. excrucians, Oc. hexodontus, Oc. intrudens, Oc. pullatus and Oc. punctor/punctodes. In total 514 viral Reverse dependent RNA polymerase (RdRp) sequences of 159 virus species were recovered, belonging to 25 families or equivalent rank, as follows: Aliusviridae, Aspiviridae, Botybirnavirus, Chrysoviridae, Chuviridae, Endornaviridae, Flaviviridae, Iflaviridae, Negevirus, Partitiviridae, Permutotetraviridae, Phasmaviridae, Phenuiviridae, Picornaviridae, Qinviridae, Quenyavirus, Rhabdoviridae, Sedoreoviridae, Solemoviridae, Spinareoviridae, Togaviridae, Totiviridae, Virgaviridae, Xinmoviridae and Yueviridae. Of these, 147 are tentatively novel viruses. One sequence of Sindbis virus, which causes Pogosta disease in humans, was detected from Oc. communis from Pohjois-Karjala. This study greatly increases the number of mosquito-associated viruses known from Finland and presents the northern-most mosquito-associated viruses in Europe to date
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