9,361 research outputs found
Factors Affecting the Decision to Choose the Farmland Model in Le Tri Commune, Tri Ton District, An Giang Province, Vietnam
The study evaluated factors affecting the selection of agricultural farming models and advantages, difficulties, and opportunities in the implementation process to propose solutions to develop appropriate agricultural sustainable farming models. The study uses secondary and primary data through KIP interviews, focus group interviews, in-depth interviews, and farmer interviews. As a result, this study found education is an important factor affecting farmers in choosing their farming models and increasing agricultural production in their farmland. For most of the considered factors, the majority of Kinh people choose to evaluate the influence of the decision in choosing a farming model higher than another ethnic group (Khmer). Besides, the Khmer ethnic group accounts for a higher proportion of poor households (18.2%) than the Kinh group. Because of low economic conditions, decisions on agricultural production of Khmer ethnic groups are less assertive than that of the Kinh people. On the other hand, there is a serious shortage of water in the dry season in the highlands, cultivated mainly by rainwater, ethnic minority accounts for 53.36% of the whole commune population, educational level makes it difficult to apply modern techniques in production. Therefore, strengthening and mobilizing people, investing in building upland irrigation systems, and using effective land conversion are essential activities to be carried out to improve the efficiency of farming models to make sustainable agricultural production that can increase income and enhance the economic life of local people
Hybridization gap and anisotropic far-infrared optical conductivity of URu2Si2
We performed far-infrared optical spectroscopy measurements on the heavy
fermion compound URu 2 Si 2 as a function of temperature. The light's
electric-field was applied along the a-axis or the c-axis of the tetragonal
structure. We show that in addition to a pronounced anisotropy, the optical
conductivity exhibits for both axis a partial suppression of spectral weight
around 12 meV and below 30 K. We attribute these observations to a change in
the bandstructure below 30 K. However, since these changes have no noticeable
impact on the entropy nor on the DC transport properties, we suggest that this
is a crossover phenomenon rather than a thermodynamic phase transition.Comment: To be published in Physical Review
Neonatal Blood Methylation Marks Associated with Obstetric Pain Relief
The placenta, responsible for intrauterine development, can facilitate modifications within the placental epigenome in response to changes in the mother. In turn these changes have the potential to also influence the neonate1. Pain relief during delivery is widely used and frequently involves the use of nitrous oxide (N2O, commonly referred to as laughing gas), and pudendal blocks. These treatments, alone or in combination, are generally accepted as safe methods of providing pain relief to mothers. However, laughing gas and local anesthetics such as the ones used during pudendal blocks have been known to cross the placental barrier from mother to child2,3. Furthermore, although current literature about the effects of laughing gas and pudendal blocks on the epigenome, when used as maternal pain relief, is very limited, some evidence implicates effects of obstetric anesthesia on the neonatal methylome2,4,5. Thus, it is reasonable to hypothesize that obstetric pain relief administered to the mother during childbirth may affect the methylome of the child. In conclusion, we detected methylome-wide significantly associated loci for laughing gas and pudendal block treatment when studied in combination, but not for either of the treatments separately.https://scholarscompass.vcu.edu/uresposters/1421/thumbnail.jp
Post-Mortem Brain Nuclei Isolation for Single Nucleus RNA Sequencing
Abstract
Post-Mortem Brain Nuclei Isolation for Single Nucleus RNA Sequencing
Charles Tran, Dept. of Biology, with Dr. Karolina Aberg, VCU School of Pharmacy
When tissue samples are studied in bulk without consideration for different cell proportions and types, results can be biased due to the attenuation of unique cellular expressions. In order to study cell type specific RNA expression profiles within tissue, single cell RNA sequencing (scRNA-seq) is used. For scRNA-seq studies it is critical to have intact cells. However, when investigating frozen post-mortem brain tissue, it is often challenging to isolate intact whole cells. An alternative solution is to instead isolate nuclei (which have similar, but not identical, transcriptomes to cells) and then perform single-nucleus RNA sequencing (snRNA-seq). In this study we have carefully optimized a protocol for nuclei extraction from post-mortem brain cells suitable for downstream snRNA-seq analysis. We found that adjusting our protocol to include less aggressive methods of tissue homogenization and sample-retaining lab techniques has resulted in the successful removal of cell debris and myelin alongside providing a workable sample size. In conclusion we have successfully evaluated and prepared enough high-quality nuclei for downstream scRNA-seq using our optimized protocol.https://scholarscompass.vcu.edu/uresposters/1398/thumbnail.jp
Solar models and solar neutrino oscillations
We provide a summary of the current knowledge, theoretical and experimental,
of solar neutrino fluxes and of the masses and mixing angles that characterize
solar neutrino oscillations. We also summarize the principal reasons for doing
new solar neutrino experiments and what we think may be learned from the future
measurements.Comment: Submitted to the Neutrino Focus Issue of New Journal of Physics at
http://www.njp.or
The Velocity Dispersion of MS1054-03: A Massive Galaxy Cluster at High Redshift
We present results from a dynamical study of the high redshift, massive,
X-ray luminous galaxy cluster MS1054--03. We significantly increase the number
of confirmed cluster members by adding 20 to an existing set of twelve; using
the confirmed members, we estimate MS1054--03's redshift, velocity dispersion,
and mass. We find that z=0.8329 +/- 0.0017, sigma = 1170 +/- 150 km/s, and the
central mass is approximately 1.9 +/- 0.5 x 10^{15} h^{-1} M_{odot} (within R=1
h^{-1} Mpc; H_0 =100h km s^{-1} Mpc^{-1}, q_0=0.5). MS1054--03 is one of a
handful of high redshift (z>0.5) clusters known that also has X-ray and
weak-lensing observations (Donahue et al. 1998; Luppino & Kaiser 1997); we find
our dynamical mass agrees with mass estimates from both studies. The
confirmation of MS1054--03 as a massive cluster at z~0.8 is consistent with an
open (Omega_M~0.3) or flat, Lambda-dominated (Omega_M+Omega_{Lambda}=1)
universe. In addition, we compare MS1054--03's velocity dispersion and X-ray
temperature to a sample of low and intermediate redshift galaxy clusters to
test for evolution in the sigma - T_x relation; we find no evidence for
evolution in this relation to z~0.8.Comment: 13 pages, 3 figures, LaTex; Accepted for Publication in the
Astrophysical Journa
Interacting Galaxies in the A901/902 Supercluster with STAGES
We present a study of galaxy mergers and the influence of environment in the
Abell 901/902 supercluster at z~0.165. We use HST ACS F606W data from the
STAGES survey, COMBO-17, Spitzer 24um, and XMM-Newton X-ray data. Our analysis
utilizes both a visual classification system, and quantitative CAS parameters
to identify systems which show evidence of a recent or ongoing merger of mass
ratio >1/10. Our results are: (1) After visual classification and minimizing
the contamination from false projection pairs, we find that the merger fraction
f_merge is 0.023+/-0.007. The estimated fractions of likely major mergers,
likely minor mergers, and ambiguous cases are 0.01+/-0.004, 0.006+/-0.003, and
0.007+/-0.003, respectively. (2) The mergers lie outside the cluster core of
radius R < 0.25 Mpc: the lack of mergers in the core is likely due to the large
galaxy velocity dispersion in the core. Mergers populate the region (0.25 Mpc <
R <= 2 Mpc) between the core and outskirt. In this region, the estimated
frequency of mergers is similar to those seen at typical group overdensities.
This suggests ongoing growth of the clusters via accretion of group and field
galaxies. (3) We compare our observed merger fraction with those reported in
other clusters and groups out to z~0.4. Existing data points on the merger
fraction for L<= L* galaxies in clusters allow for a range of evolutionary
scenarios. (4) The fraction of mergers, which lie on the blue cloud is
80%+/-18% versus 34%+/-7% for non-interacting galaxies, implying that
interacting galaxies are preferentially blue. (5) The average SFR, based on UV
or UV+IR data, is enhanced by a factor of ~1.5 to 2 in mergers compared to
non-interacting galaxies. However, mergers in the clusters contribute only a
small fraction (between 10% and 15%) of the total SFR density.(Abridged)Comment: Accepted for publication in ApJ. 34 pages, 16 figures. Version with
full resolution figures available at: http://www.as.utexas.edu/~alh/apj/int/
; updated abridged abstrac
Multiple Imputation Ensembles (MIE) for dealing with missing data
Missing data is a significant issue in many real-world datasets, yet there are no robust methods for dealing with it appropriately. In this paper, we propose a robust approach to dealing with missing data in classification problems: Multiple Imputation Ensembles (MIE). Our method integrates two approaches: multiple imputation and ensemble methods and compares two types of ensembles: bagging and stacking. We also propose a robust experimental set-up using 20 benchmark datasets from the UCI machine learning repository. For each dataset, we introduce increasing amounts of data Missing Completely at Random. Firstly, we use a number of single/multiple imputation methods to recover the missing values and then ensemble a number of different classifiers built on the imputed data. We assess the quality of the imputation by using dissimilarity measures. We also evaluate the MIE performance by comparing classification accuracy on the complete and imputed data. Furthermore, we use the accuracy of simple imputation as a benchmark for comparison. We find that our proposed approach combining multiple imputation with ensemble techniques outperform others, particularly as missing data increases
The Middle-Income Trap: Issues for Members of the Association of Southeast Asian Nations
The problem faced by many of the economies making up the Association of Southeast Asian Nations (ASEAN) is whether they can avoid the middle-income trap and advance to the high-income level. What is needed for them to avoid the middle-income trap? This paper attempts to answer this question by building an analytical framework based on the factors that determine each development stage of an economy, and by comparing the current situation of four ASEAN middle-income countries with the experience of the Republic of Korea, a country that managed to overcome the middle-income trap and reach the high-income level in the late 1990s. The paper concludes that for ASEAN middle-income countries (Indonesia, Malaysia, the Philippines, and Thailand) to avoid the trap, they should strengthen research and development capability, emphasize the quality and appropriateness of human resources, and improve the institutional system for nourishing a dynamic private sector. These efforts can be expected to result in dynamic changes in the structure of comparative advantage toward higher skill and more innovation-intensive contents of products. For a low middle-income country such as Viet Nam, reforms and policies to increase the productivity of capital, land, and other resources are essential to avoid the early appearance of the trap
On quantum teleportation with beam-splitter-generated entanglement
Following the lead of Cochrane, Milburn, and Munro [Phys. Rev. A {\bf 62},
062307 (2000)], we investigate theoretically quantum teleportation by means of
the number-sum and phase-difference variables. We study Fock-state entanglement
generated by a beam splitter and show that two-mode Fock-state inputs can be
entangled by a beam splitter into close approximations of maximally entangled
eigenstates of the phase difference and the photon-number sum
(Einstein-Podolsky-Rosen -- EPR -- states). Such states could be experimentally
feasible with on-demand single-photon sources. We show that the teleportation
fidelity can reach near unity when such ``quasi-EPR'' states are used as the
quantum channel.Comment: 7 pages (two-column), 7 figures, submitted to Phys. Rev. A. Text
unmodified, postscript error correcte
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