958 research outputs found
Integrated atomistic process and device simulation of decananometre MOSFETs
In this paper we present a methodology for the integrated atomistic process and device simulation of decananometre MOSFETs. The atomistic process simulations were carried out using the kinetic Monte Carlo process simulator DADOS, which is now integrated into the Synopsys 3D process and device simulation suite Taurus. The device simulations were performed using the Glasgow 3D statistical atomistic simulator, which incorporates density gradient quantum corrections. The overall methodology is illustrated in the atomistic process and device simulation of a well behaved 35 nm physical gate length MOSFET reported by Toshiba
Unsuccessful Cassava Brown Streak Disease (CBSD) evaluation attempts in western Democratic Republic of Congo and implications with cassava root necrosis disease (CRND) etiology
Open Access ArticleCassava brown streak disease (CBSD) is the second most important virus disease after Cassava mosaic disease (CMD), infecting cassava (ManihotesculetaCrantz) in Africa. The disease is caused by two distinct viruses, Cassava brown streak virus [2, 3] and Ugandan Cassava brown streak virus (family, Potyviridae: genus, Ipomovirus). Transmission of CBSV from one plant to another is reported to occur through grafting CBSV-free with infected cuttings and subsequent dissemination by infected cuttings. The basic approach to control of CBSD is selecting planting material from symptomless mother plants. Graft inoculation is the most efficient and effective of the techniques for CBSD virus transmission and consequently cuttings are the most effective way of the disease spreading.
In early 2000s, cassava root necrosis similar to those of CBSD were reported in western provinces of Democratic Republic of Congo (RDC) (Kinshasa and Kongo Central) and up to date PCR diagnoses did not detect any causal agent related to the observed symptoms and the disease which was still referred as ‘CBSD-like disease’.
Due to lack of molecular data and the similarity of root symptoms with CBSD, the existence of a virus has always been suspected to be the cause of CBSD-like propagation. Thus, 2 field experiments were proposed in order to verify the existence of a systematic transmission of a possible CBSD related virus, knowing that CBSD viruses are transmitted efficiently by cuttings.
The first trial focused on the field evaluation of CBSD – like infected and apparently uninfected planting materials, while the second trial involved the importation of tanzanian CBSD resistant genotypes for evaluation in INERA Mvuazi research center under CBSD-like infection conditions.
Results of the first trial did not show a systemic transmission of any CBSD-like pathogen while CBSD-resistant parents involved in the second trial all succumbed to CBSD-like disease
First observation of liquid xenon electroluminescence with a Microstrip Plate
We report on the first observation of electroluminescence amplification with
a Microstrip Plate immersed in liquid xenon. The electroluminescence of the
liquid, induced by alpha-particles, was observed in an intense non-uniform
electric field in the vicinity of 8-m narrow anode strips interlaced with
wider cathode ones, deposited on the same side of a glass substrate. The
electroluminescence yield in the liquid reached a value of VUV
photons/electron. We propose ways of enhancing this response with more
appropriate microstructures towards their potential incorporation as sensing
elements in single-phase noble-liquid detectors.Comment: 17 pages, 14 figures, prepared for submission to JINS
Multilocational Testing of Grasses and Legumes in the Humid Tropics of South America
Adaptability of 5 grass and 13 legume accessions tested in 34 regional agronomic trials throughout the South American humid tropics was assessed by conducting a multilocational analysis on seasonal dry matter (DM) yield at 12 weeks regrowth. Among legumes, Stylosamhes guianensis CIAT 184 and 136, Desmodium ovaifolum CIAT 350, Zornia latifolla CIAT 728 and Centrosema macrocarpum CIAT 5065 were the highest yielding accessions in both rainfall periods and showed high adaptability to environmental conditions. Centrosema brasllianan CIAT 5234, C. pubescence CIAT 438 and Desmodiun heterophyifom CIAT 349 had low productivity and low adaptability. For grasses, Andropogon gayanus CIAT 621 outyielded Brachiaria briwntha ClAT 6780, B. decumbens CIAT 606, B. dictyoneura CIAT 6133 and B. llumidicola CIAT 679 during the high rainfall period but had DM yields similar to that of the other accessions during the low rainfall period, except for CIAT 679, which produced less DM. During minimum rainfall, B. brfaantha CIAT 6780 showed the highest environmental adaptability, followed by A. gayanus CIAT 621 and B. dictyoneura CIAT 6133, while lower adaptability was recorded for B. decumbe11s CIAT 606 and B. humid/cola CIAT 679. During maximum rainfall, all accessions showed an intermediate adaptability to, environmental conditions. This study demonstrated that a range of adapted forage legume and grass options are now available for the South American humid tropics
Sensitivity of the NEXT experiment to Xe-124 double electron capture
ArtÃculo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMDouble electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture (2νEC EC) has been predicted for a number of isotopes, but only observed in 78Kr, 130Ba and, recently, 124Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, 0νEC EC. Here we report on the current sensitivity of the NEXT-White detector to 124Xe 2νEC EC and on the extrapolation to NEXT-100. Using simulated data for the 2νEC EC signal and real data from NEXT-White operated with 124Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of 124Xe and for a 5-year run, a sensitivity to the 2νEC EC half-life of 6 × 1022 y (at 90% confidence level) or better can be reache
Electron transfer efficiency in liquid xenon across THGEM holes
Dual-phase liquid-xenon time projection chambers (LXe TPCs) deploying a few
tonnes of liquid are presently leading the search for WIMP dark matter. Scaling
these detectors to 10-fold larger fiducial masses, while improving their
sensitivity to low-mass WIMPs presents difficult challenges in detector design.
Several groups are considering a departure from current schemes, towards either
single-phase liquid-only TPCs, or dual-phase detectors where the
electroluminescence region consists of patterned electrodes. Here, we discuss
the possible use of Thick Gaseous Electron Multipliers (THGEMs) coated with a
VUV photocathode and immersed in LXe as a building block in such designs. We
focus on the transfer efficiencies of ionization electrons and photoelectrons
emitted from the photocathode through the electrode holes, and show
experimentally that efficiencies approaching 100 % can be achieved with
realistic voltage settings. The observed voltage dependence of the transfer
efficiencies is consistent with electron transport simulations once diffusion
and charging-up effects are included
The dimerized phase of ionic Hubbard models
We derive an effective Hamiltonian for the ionic Hubbard model at half
filling, extended to include nearest-neighbor repulsion. Using a spin-particle
transformation, the effective model is mapped onto simple spin-1 models in two
particular cases. Using another spin-particle transformation, a slightly
modified model is mapped into an SU(3) antiferromagnetic Heisenberg model whose
exact ground state is known to be spontaneously dimerized. From the effective
models several properties of the dimerized phase are discussed, like
ferroelectricity and fractional charge excitations. Using bosonization and
recent developments in the theory of macroscopic polarization, we show that the
polarization is proportional to the charge of the elementary excitations
The Parental Involvement in Academic Performance in C Secondary Schools at Ukerewe District Council.
The study focused on the parental school involvement in children education in Ukerewe district. Three objectives were: to investigate the status of parental in school involvement in education of their children in Ukerewe District Council, to analyze challenges parents experience in school involvement of their children education, and to establish strategies to improve parental school involvement in selected secondary schools in Ukerewe District Council. The study used mixed methods design where questionnaire and interviews were used. The results showed that parents in Ukerewe had taken the issues of parental school involvement being teachers' and students' obligation. Evidences showed parents were not communicating to teachers, parents did not checking students’ assignments, and follow children school report. The only thing parents did was to contribute to fundraising. The status showed parents had low involvement in education. Thus was not expected to make and enhance school children academic performance in any way in Ukerewe secondary schools. Poor students readiness to learn, family conflict arising family, failure to set time to supervise students learning activities and general students discipline at home, and busy schedule of parents all these added to low parental involvement in school activities. The strategies to improve the situation were parents to attend school parents meeting, school enhancing home visits programme and school to do partnership with community on school matters. The Recommendations to improve the situation are attached. Keywords: Parental Involvement, Academic Performance, Ukerew
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First report and preliminary evaluation of cassava root necrosis in Angola
Open Access ArticleCassava is a main staple food for 800 million people world-wide. Production is limited by pest and pathogens. The most devastating cassava viruses are Cassava Brown Streak Virus and Uganda Cassava Brown Streak Virusboth causing severe root necrosis called Cassava Brown Streak Disease. In the last 10 years, the Cassava Brown Streak Disease (CBSD)has spread across Africa from the east coast of Africa to central Africa. Similar root necrosis to cassava brown streak disease has also been identified in the Democratic Republic of Congo where the first symptoms were identified in 2002 in Kinshasa and Kongo central province. In 2012, the presence of CBSD was confirmed in eastern Democratic Republic of Congo. All attempts since 2002 in western Democratic Republic of Congo to identify the cause of these root necrosis have failed. In 2017, a team of scientists surveying the Songololo Territory in the Kongo central province at the northern Angola, identified the same root necrosis similar to CBSD in several localities bordering Angola. These unexpected results will foreshadow the presence of cassava root necrosis in Angola. This preliminary investigation in northern Angola was conducted specifically in the Zaire province and the territory of Mbanza Kongo at approximatively 62 kms from the Democratic Republic of Congo border in order to verify, whether or not, these root necrosis are present in Angola. Results obtained from this exploratory survey in several fields of the Zaire province and territory of Mbanza Kongo confirmed, for the first time, the presence of cassava root necrosis in Angola, similar to CBSD, as identified in western DRC
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