3,384 research outputs found
Comparing the Profitability of Hybrid, Inbred, and Organic Rice Production
Rice is a staple food for most Filipinos across the country, with more than 90% of Filipinos consuming it on a daily basis. In the past two decades, annual supply of rice at 2.18% has not been enough to sustain the country’s needs, whose annual population increases at 2.20%. One of the most significant programs of the government for the rice sector is to enhance provincial rice self-sufficiency through the use of proven farming technologies that not only increase yield but also raise farmers’ incomes. Given the options to attain higher yields, this study investigated the profitability of certified inbred varieties, hybrid, and organic rice by determining the cost of production and net income of farmers and using partial budget analysis. Results show that rice farmers who ventured into hybrid rice production incurred the highest production cost per hectare per cropping (PhP37,428.521) compared to inbred (PhP26,717.64) and organic (PhP30,210.81) rice production. Hybrid rice production gave the highest income for farmers per hectare per cropping (PhP147,690.54) compared to inbred (PhP113,006.44) and organic (PhP84,785.46) rice productions. Partial budget analysis showed that additional income was gained by rice farmers shifting from organic to hybrid rice production per hectare per cropping (PhP43,195.25) and those shifting from inbred to organic rice production (PhP6,394.06). However, farmers shifting from organic to inbred rice production lost income amounting to PhP16,994.56 per hectare per cropping due to added cost such as farm inputs, labor, and low yield. To conclude, planting hybrid variety is recommended as it gives farmers the highest net income
Dealing with a traumatic past: the victim hearings of the South African truth and reconciliation commission and their reconciliation discourse
In the final years of the twentieth and the beginning of the twenty-first century, there has been a worldwide tendency to approach conflict resolution from a restorative rather than from a retributive perspective. The South African Truth and Reconciliation Commission (TRC), with its principle of 'amnesty for truth' was a turning point. Based on my discursive research of the TRC victim hearings, I would argue that it was on a discursive level in particular that the Truth Commission has exerted/is still exerting a long-lasting impact on South African society. In this article, three of these features will be highlighted and illustrated: firstly, the TRC provided a discursive forum for thousands of ordinary citizens. Secondly, by means of testimonies from apartheid victims and perpetrators, the TRC composed an officially recognised archive of the apartheid past. Thirdly, the reconciliation discourse created at the TRC victim hearings formed a template for talking about a traumatic past, and it opened up the debate on reconciliation. By discussing these three features and their social impact, it will become clear that the way in which the apartheid past was remembered at the victim hearings seemed to have been determined, not so much by political concerns, but mainly by social needs
Minute-of-Arc Resolution Gamma ray Imaging Experiment—MARGIE
MARGIE (Minute-of-Arc Resolution Gamma-ray Imaging Experiment) is a large area(∼104 cm2), wide field-of-view (∼1 sr), hard X-ray/gamma-ray (∼20–600 keV) coded-mask imaging telescope capable of performing a sensitive survey of both steady and transient cosmic sources. MARGIE has been selected for a NASA mission-concept study for an Ultra Long Duration (100 day) Balloon flight. We describe our program to develop the instrument based on new detector technology of either cadmium zinc telluride (CZT) semiconductors or pixellated cesium iodide (CsI) scintillators viewed by fast-timing bi-directional charge-coupled devices (CCDs). The primary scientific objectives are to image faint Gamma-Ray Bursts (GRBs) in near-real-time at the low intensity (high-redshift) end of the logN-logS distribution, thereby extending the sensitivity of present observations, and to perform a wide field survey of the Galactic plane
MARGIE: A gamma-ray burst ultra-long duration balloon mission
We are designing MARGIE as a 100 day ULDB mission to: a) detect and localize gamma-ray bursts; and b) survey the hard X-ray sky. MARGIE will consist of one small field-of-view (FOV) and four large FOV coded mask modules mounted on a balloon gondola. The burst position will be calculated onboard and disseminated in near-real time, while information about every count will be telemetered to the ground for further analysis. In a 100-day mission we will localize ∼40 bursts with peak photon fluxes from 0.14 to ∼5 ph cm−2 s−1 using 1 s integrations; the typical localization resolution will be better than ∼2 arcminutes
Dicer-2 Processes Diverse Viral RNA Species
RNA silencing pathways play critical roles in gene regulation, virus infection, and transposon control. RNA interference (RNAi) is mediated by small interfering RNAs (siRNAs), which are liberated from double-stranded (ds)RNA precursors by Dicer and guide the RNA-induced silencing complex (RISC) to targets. Although principles governing small RNA sorting into RISC have been uncovered, the spectrum of RNA species that can be targeted by Dicer proteins, particularly the viral RNAs present during an infection, are poorly understood. Dicer-2 potently restricts viral infection in insects by generating virus-derived siRNAs from viral RNA. To better characterize the substrates of Dicer-2, we examined the virus-derived siRNAs produced during the Drosophila antiviral RNAi response to four different viruses using high-throughput sequencing. We found that each virus was uniquely targeted by the RNAi pathway; dicing substrates included dsRNA replication intermediates and intramolecular RNA stem loops. For instance, a putative intergenic RNA hairpin encoded by Rift Valley Fever virus generates abundant small RNAs in both Drosophila and mosquito cells, while repetitive sequences within the genomic termini of Vaccinia virus, which give rise to abundant small RNAs in Drosophila, were found to be transcribed in both insect and mammalian cells. Moreover, we provide evidence that the RNA species targeted by Dicer-2 can be modulated by the presence of a viral suppressor of RNAi. This study uncovered several novel, heavily targeted features within viral genomes, offering insight into viral replication, viral immune evasion strategies, and the mechanism of antiviral RNAi. © 2013 Sabin et al
Approaching the knee -- balloon-borne observations of cosmic ray composition
Below the knee in the cosmic ray spectrum, balloon and spacecraft experiments
offer the capability of direct composition and energy measurements on the
primary particles. A major difficulty is obtaining enough exposure to extend
the range of direct measurements sufficiently high in energy to permit overlap
with ground-based observations. Presently, balloon and space measurements
extend only up to ~100 TeV, well below the range of ground-based experiments.
The prospect of Ultra-Long Duration Balloon missions offers the promise of
multiple long flights that can build up exposure. The status of balloon
measurements to measure the high energy proton and nuclear composition and
spectrum is reviewed, and the statistical considerations involved in searching
for a steepening in the spectrum are discussed. Given the very steeply falling
spectrum, it appears unlikely that balloon experiments will be able to extend
the range of direct measurements beyond 1000 TeV any time in the near future.
Especially given the recent suggestions from KASCADE that the proton spectrum
steepens only at 4000-5000 TeV, the chance of detecting the knee with direct
measurements of protons to iron on balloons is not likely to occur without
significant increases in the payload and flight duration capabilities of high
altitude balloons.Comment: 10 pages, to be published, J. Phys. Conf. Ser. (Proc. Workshop on
Physics at the End of the Galactic Cosmic Ray Spectrum, Aspen, April 2005
Model for Spreading of Liquid Monolayers
Manipulating fluids at the nanoscale within networks of channels or chemical
lanes is a crucial challenge in developing small scale devices to be used in
microreactors or chemical sensors. In this context, ultra-thin (i.e.,
monolayer) films, experimentally observed in spreading of nano-droplets or upon
extraction from reservoirs in capillary rise geometries, represent an extreme
limit which is of physical and technological relevance since the dynamics is
governed solely by capillary forces. In this work we use kinetic Monte Carlo
(KMC) simulations to analyze in detail a simple, but realistic model proposed
by Burlatsky \textit{et al.} \cite{Burlatsky_prl96,Oshanin_jml} for the
two-dimensional spreading on homogeneous substrates of a fluid monolayer which
is extracted from a reservoir. Our simulations confirm the previously predicted
time-dependence of the spreading, , with as
the average position of the advancing edge at time , and they reveal a
non-trivial dependence of the prefactor on the strength of
inter-particle attraction and on the fluid density at the reservoir as
well as an -dependent spatial structure of the density profile of the
monolayer. The asymptotic density profile at long time and large spatial scale
is carefully analyzed within the continuum limit. We show that including the
effect of correlations in an effective manner into the standard mean-field
description leads to predictions both for the value of the threshold
interaction above which phase segregation occurs and for the density profiles
in excellent agreement with KMC simulations results.Comment: 21 pages, 9 figures, submitted to Phys. Rev.
Computationally designed libraries of fluorescent proteins evaluated by preservation and diversity of function
To determine which of seven library design algorithms best introduces new protein function without destroying it altogether, seven combinatorial libraries of green fluorescent protein variants were designed and synthesized. Each was evaluated by distributions of emission intensity and color compiled from measurements made in vivo. Additional comparisons were made with a library constructed by error-prone PCR. Among the designed libraries, fluorescent function was preserved for the greatest fraction of samples in a library designed by using a structure-based computational method developed and described here. A trend was observed toward greater diversity of color in designed libraries that better preserved fluorescence. Contrary to trends observed among libraries constructed by error-prone PCR, preservation of function was observed to increase with a library's average mutation level among the four libraries designed with structure-based computational methods
Studying Kaon-pion S-wave scattering in K-matrix formalism
We generalize our previous work on \pi\pi scattering to K\pi scattering, and
re-analyze the experiment data of K\pi scattering below 1.6 GeV. Without any
free parameter, we explain K\pi I=3/2 S-wave phase shift very well by using
t-channel rho and u-channel K^* meson exchange. With the t-channel and
u-channel meson exchange fixed as the background term, we fit the K\pi I=1/2
S-wave data of the LASS experiment quite well by introducing one or two
s-channel resonances. It is found that there is only one s-channel resonance
between K\pi threshold and 1.6 GeV, i.e., K_0^*(1430) with a mass around
1438~1486 MeV and a width about 346 MeV, while the t-channel rho exchange gives
a pole at (450-480i) MeV for the amplitude.Comment: REVTeX4 file, 11 pages and 3 figure
- …