559 research outputs found
Incommensurate spin resonance in URu2Si2
We focus on inelastic neutron scattering in and argue that
observed gap in the fermion spectrum naturally leads to the spin feature
observed at energies at momenta at \bQ^* = (1\pm 0.4,
0,0). We discuss how spin features seen in can indeed be thought
of in terms of {\em spin resonance} that develops in HO state and is {\em not
related} to superconducting transition at 1.5K. In our analysis we assume that
the HO gap is due to a particle-hole condensate that connects nested parts of
the Fermi surface with nesting vector . Within this approach we can
predicted the behavior of the spin susceptibility at \bQ^* and find it to be
is strikingly similar to the phenomenology of resonance peaks in high-T and
heavy fermion superconductors. The energy of the resonance peak scales with
. We discuss observable consequences
spin resonance will have on neutron scattering and local density of states.Comment: 8 pgaes latex, 4 fig
Effect of biochar and nitrogen on soil characteristics, growth and yield of radish (Raphanus sativus L.) at Paklihawa, Rupandehi condition of Nepal
An experiment on effect of biochar and nitrogen on soil characteristics, growth and yield of radish (Raphanus sativus L.) was conducted at Institute of Agriculture and Animal Science (IAAS), Paklihawa, Rupandehi, from November 2019 to February 2020. The experiment was laid in Randomized Complete Block Design with two factors: nitrogen and biochar, each factor having four levels (biochar: 0 t/ha, 5 t/ha, 10 t/ha and 15 t/ha and nitrogen: 0 kg/ha, 50 kg/ha, 100 kg/ha, 200 kg/ha), resulting in sixteen treatment combinations. Biochar application was found to be effective in improving soil bulk density, pH, soil organic matter and soil nitrogen and potassium content. Application of nitrogen fertilizer (200 kg/ha) and biochar (15 t/ha) alone, and in combination, showed significantly higher root dry matter (15.83 gm, 16.63 gm and 20.57 gm), biological yield (80 t/ha, 63.75 t/ha, and 95.75) and root yield (26.74 t/ha, 24.06 t/ha and 30.32 t/ha). In comparison to the sole effects of the highest dose of nitrogen fertilizer (200 kg/ha) and the highest dose of biochar (15 t/ha), their combined application showed the increased yield in radish root by 13.38% and 26.01%, respectively, indicating that the combined effect of biochar and nitrogen is more productive for the growth and yield in radish crop as compared to the sole effect of nitrogen and biochar
Effect of Different Spacing and Mulching on Growth and Yield of Okra (Abelmoschus Esculentus L.) in Chitwan, Nepal
Okra (Abelmoschus esculentus L.) is one of the most important vegetable crop of Nepal. Its yield and growth parameters are affected by different cultural practices. This study was conducted at Olericulture Farm of Agriculture and Forestry University, Rampur, Chitwan, Nepal during April 29 to July 9 of 2018. The field experiment was carried out in split plot design using three replications. The treatments consisted of three intra row spacing (30, 45 and 60 cm) and four different mulching materials (Silver plastic, Panicum repens, Lantana camara and bare soil). The objective of this experiment was to assess the effects of various intra-row spacings and mulching materials on growth and yield of okra. The effect of mulching materials on okra yield was found significant. The okra yield was highest (8104 kg/ha) under silver plastic mulch followed by control (5161kg/ha), Panicum repens (3901kg/ha) and Lantana camera (3701kg/ha), respectively. Silver plastic mulch enhanced the growth parameters like canopy length, plant height, leaf number, leaf length, girth and yield of okra. The spacings provided non significant effect on okra yield, however the yield of okra was highest (7295 kg/ha) under 30×30 cm spacing followed by 45×30 cm (4660 kg/ha) and 60 cm × 30 cm spacing (3703 kg/ha), respectively. Combination of silver plastic mulch along with 30 cm × 30 cm spacing provided the highest okra yield. This study suggests that farmers of the Chitwan should grow okra at spacing of 30 cm × 30 cm and under silver plastic mulch to produce higher yield
X-ray and Synchrotron FTIR Studies of Partially Decomposed Magnesium Borohydride
Magnesium borohydride (Mg(BH4)(2)) is an attractive compound for solid-state hydrogen storage due to its lucratively high hydrogen densities and theoretically low operational temperature. Hydrogen release from Mg(BH4)(2) occurs through several steps. The reaction intermediates formed at these steps have been extensively studied for a decade. In this work, we apply spectroscopic methods that have rarely been used in such studies to provide alternative insights into the nature of the reaction intermediates. The commercially obtained sample was decomposed in argon flow during thermogravimetric analysis combined with differential scanning calorimetry (TGA-DSC) to differentiate between the H-2-desorption reaction steps. The reaction products were analyzed by powder X-ray diffraction (PXRD), near edge soft X-ray absorption spectroscopy at boron K-edge (NEXAFS), and synchrotron infrared (IR) spectroscopy in mid- and far-IR ranges (SR-FTIR). Up to 12 wt% of H-2 desorption was observed in the gravimetric measurements. PXRD showed no crystalline decomposition products when heated at 260-280 degrees C, the formation of MgH2 above 300 degrees C, and Mg above 320 degrees C. The qualitative analysis of the NEXAFS data showed the presence of boron in lower oxidation states than in (BH4)(-). The NEXAFS data also indicated the presence of amorphous boron at and above 340 degrees C. This study provides additional insights into the decomposition reaction of Mg(BH4)(2)
Edge states in a honeycomb lattice: effects of anisotropic hopping and mixed edges
We study the edge states in graphene in the presence of a magnetic field
perpendicular to the plane of the lattice. Most of the works done so far
discuss the edge states in either zigzag or armchair edge graphene considering
an isotropic electron hopping. In practice, graphene can have mixture of
armchair and zigzag edges and the electron hopping can be anisotropic, which is
the subject of this article. We predict that the mixed edges smear the enhanced
local density of states (LDOS) at E=0 of the zigzag edge and, on the other
hand, the anisotropic hopping gives rise to the enhanced LDOS at E=0 in the
armchair edge. The behavior of the LDOS can be studied using scanning tunneling
microscopy (STM) experiments. We suggest that care must be taken while
interpreting the STM data. It is because the clear distinction between the
zigzag edge (enhanced LDOS at E=0) and armchair edge (suppressed LDOS at E=0)
can be lost if the hopping is not isotropic and if the edges are mixed
Remarks on the tight-binding model of graphene
We address a simple but fundamental issue arising in the study of graphene,
as well as of other systems that have a crystalline structure with more than
one atom per unit cell. For these systems, the choice of the tight-binding
basis is not unique. For monolayer graphene two bases are widely used in the
literature. While the expectation values of operators describing physical
quantities should be independent of basis, the form of the operators may depend
on the basis, especially in the presence of disorder or of an applied magnetic
field. Using the inappropriate form of certain operators may lead to erroneous
physical predictions. We discuss the two bases used to describe monolayer
graphene, as well as the form of the most commonly used operators in the two
bases. We repeat our analysis for the case of bilayer graphene.Comment: 15 pages, 4 figure
Effects of climatic factors on diarrheal diseases among children below 5 years of age at national and subnational levels in Nepal: an ecological study
INTRODUCTION: The incidence of diarrhea, a leading cause of morbidity and mortality in low-income countries such as Nepal, is temperature-sensitive, suggesting it could be associated with climate change. With climate change fueled increases in the mean and variability of temperature and precipitation, the incidence of water and food-borne diseases are increasing, particularly in sub-Saharan Africa and South Asia. This national-level ecological study was undertaken to provide evidence linking weather and climate with diarrhea incidence in Nepal. METHOD: We analyzed monthly diarrheal disease count and meteorological data from all districts, spanning 15 eco-development regions of Nepal. Meteorological data and monthly data on diarrheal disease were sourced, respectively, from the Department of Hydrology and Meteorology and Health Management Information System (HMIS) of the Government of Nepal for the period from 2002 to 2014. Time-series log-linear regression models assessed the relationship between maximum temperature, minimum temperature, rainfall, relative humidity, and diarrhea burden. Predictors with p-values < 0.25 were retained in the fitted models. RESULTS: Overall, diarrheal disease incidence in Nepal significantly increased with 1 degrees C increase in mean temperature (4.4%; 95% CI: 3.95, 4.85) and 1 cm increase in rainfall (0.28%; 95% CI: 0.15, 0.41). Seasonal variation of diarrheal incidence was prominent at the national level (11.63% rise in diarrheal cases in summer (95% CI: 4.17, 19.61) and 14.5% decrease in spring (95% CI: -18.81, -10.02) compared to winter season). Moreover, the effects of temperature and rainfall were highest in the mountain region compared to other ecological regions of Nepal. CONCLUSION: Our study provides empirical evidence linking weather factors and diarrheal disease burden in Nepal. This evidence suggests that additional climate change could increase diarrheal disease incidence across the nation. Mountainous regions are more sensitive to climate variability and consequently the burden of diarrheal diseases. These findings can be utilized to allocate necessary resources and envision a weather-based early warning system for the prevention and control of diarrheal diseases in Nepal
On the Meissner Effect of the Odd-Frequency Superconductivity with Critical Spin Fluctuations: Possibility of Zero Field FFLO pairing
We investigate the influence of critical spin fluctuations on electromagnetic
responses in the odd-frequency superconductivity. It is shown that the Meissner
kernel of the odd-frequency superconductivity is strongly reduced by the
critical spin fluctuation or the massless spin wave mode in the
antiferromagnetic phase. These results imply that the superfluid density is
reduced, and the London penetration depth is lengthened for the odd-frequency
pairing. It is also shown that the zero field Flude-Ferrell-Larkin-Ovchinnikov
pairing is spontaneously realized both for even- and odd-frequency in the case
of sufficiently strong coupling with low lying spin-modes.Comment: 10 pages, 7 figure
Relationship between natural occurrence of banana streak badnavirus and symptom expression, relative concentration of viral antigen, and yield characteristics of some micropropagated Musa spp.
Micropropagated plants of 36 Musa genotypes with diverse genetic backgrounds, including 14 tetraploid plantain (TMPx) and banana (TMBx) hybrids, were evaluated for their response to banana streak badnavirus (BSV) infection under three environments from 1995 to 1997 in Nigeria. The characteristics evaluated were the natural incidence of BSV based on symptoms and virus indexing, relative concentration of BSV antigens in leaf tissues determined by ELISA, and some growth and yield descriptors. Virus occurrence and symptom expression, as well as the relative concentration of BSV antigens, fluctuated greatly between seasons during the cropping cycle, being high during the rainy season and low or negligible during the hot dry season. The natural incidence of plants with symptoms and BSV-infected plants varied between genotypes. Incidence of BSV on most International Institute of Tropical Agriculture (IITA) TMPx hybrids and three Fundación Hondureòa de Investigación Agrìcola (FHIA) hybrids was high in the three environments, with some variation. Most landraces and some FHIA or Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA) hybrids were not BSV-infected under either environment at Onne. However, a few expressed some foliar symptoms at Ibadan and indexed BSV positive. The relative concentration of BSV antigens in leaf samples was also high in most TMPx and some FHIA hybrids, but low in most landraces. While BSV infection had no significant effect on most growth characteristics, it had a highly variable effect on bunch weight loss among the genotypes. There was no relationship between the natural incidence of BSV, concentration of viral antigen and bunch weight loss among the 11 TMPx hybrids, three FHIA hybrids and three plantain landraces. Despite the high natural BSV incidence and the high relative antigen concentration in their leaf tissue, TMPx 548-9, TMPx 2637-49, TMPx 7002-1 and FHIA 21 suffered less than 15% bunch weight loss, and TMPx 548-4 and FHIA 22 suffered no loss. These results suggest that under the conditions specified in this study, these hybrids could be tentatively classified as ‘field tolerant’ to BS
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