3,728 research outputs found
Bethe-Salpeter Equation Calculations of Core Excitation Spectra
We present a hybrid approach for GW/Bethe-Salpeter Equation (BSE)
calculations of core excitation spectra, including x-ray absorption (XAS),
electron energy loss spectra (EELS), and non-resonant inelastic x-ray
scattering (NRIXS). The method is based on {\it ab initio} wavefunctions from
the plane-wave pseudopotential code ABINIT; atomic core-level states and
projector augmented wave (PAW) transition matrix elements; the NIST core-level
BSE solver; and a many-pole GW self-energy model to account for final-state
broadening and self-energy shifts. Multiplet effects are also accounted for.
The approach is implemented using an interface dubbed OCEAN (Obtaining Core
Excitations using ABINIT and NBSE). To demonstrate the utility of the code we
present results for the K-edges in LiF as probed by XAS and NRIXS, the K-edges
of KCl as probed by XAS, the Ti L_2,3-edge in SrTiO_3 as probed by XAS, and the
Mg L_2,3-edge in MgO as probed by XAS. We compare the results to experiments
and results obtained using other theoretical approaches
Recommended from our members
The cardiomyocyte "redox rheostat": Redox signalling via the AMPK-mTOR axis and regulation of gene and protein expression balancing survival and death.
Reactive oxygen species (ROS) play a key role in development of heart failure but, at a cellular level, their effects range from cytoprotection to induction of cell death. Understanding how this is regulated is crucial to develop novel strategies to ameliorate only the detrimental effects. Here, we revisited the fundamental hypothesis that the level of ROS per se is a key factor in the cellular response by applying different concentrations of H2O2 to cardiomyocytes. High concentrations rapidly reduced intracellular ATP and inhibited protein synthesis. This was associated with activation of AMPK which phosphorylated and inhibited Raptor, a crucial component of mTOR complex-1 that regulates protein synthesis. Inhibition of protein synthesis by high concentrations of H2O2 prevents synthesis of immediate early gene products required for downstream gene expression, and such mRNAs (many encoding proteins required to deal with oxidant stress) were only induced by lower concentrations. Lower concentrations of H2O2 promoted mTOR phosphorylation, associated with differential recruitment of some mRNAs to the polysomes for translation. Some of the upregulated genes induced by low H2O2 levels are cytoprotective. We identified p21Cip1/WAF1 as one such protein, and preventing its upregulation enhanced the rate of cardiomyocyte apoptosis. The data support the concept of a "redox rheostat" in which different degrees of ROS influence cell energetics and intracellular signalling pathways to regulate mRNA and protein expression. This sliding scale determines cell fate, modulating survival vs death
Automated System for Detection of Apple Purity and Its Grading
It is always a common problem for all the people to identify the purity of all the fruits that has been purchased from the �fruit mandi� or local fruit stores. In this paper we would like to propose an idea for identifying the purity of apples. At present, among all the apples that are being sold in a shop, only few samples are collected and tested for purity in the laboratories by food Corporation of INDIA (FOI), which might not ensure that all the apples being sold in that respective shop/market are pure. In this paper we are proposing a device which can sense if the chosen apple is pure or not and which can be used by all the common people who are purchasing fruits from the market. Through this infections and disorders caused by fruits consumption can be eradicated to some extent
Payment for Environmental Services: Status and Opportunities in Kenya
Payment for Ecosystem Service (PES) is a market driven tool to motivate upstream land owners to practices land uses that enhance water quantity flows through compensation incentive packages supported by downstream beneficiaries and partners. PES is a voluntary engagement that involves negotiation by sellers and buyers of ecosystem products and services through independent intermediaries. The country is facing high deforestation and degradation rates within the key watersheds that threaten future supply of water for various socioeconomic activities. The PES concept has been around for the last two decades and many projects have been undertaken in the country hence the need to evaluate its adoption rates and subsequent outcomes to inform future direction of research and investments in PES schemes in the country. A study was initiated by Kenya Forestry Research Institute (KEFRI) and partners in 2016 to collect information on the experiences by several projects in the implementation of PES schemes. This was informed by the fact that information and data on use of PES in watershed management in Kenya is scanty and disjointed hence the needs for comprehensive study to update stakeholders on its status and experiences. Similarly, the country has to manage its watersheds in accordance with international standards and hence needs to tap into the most effective approaches and technologies available within its socioeconomic and ecological contexts. The study results indicate that the country has put in place some policy and legal framework to support PES piloting schemes. The cross sector study identified 15 projects on carbon sequestration, biodiversity conservation, watershed protection and a bundled combination of these services that have been implemented in the country. PES schemes promoted conservation friendly land uses and offered a wide range of incentives to communities and individuals who are custodians of the natural resources through negotiated engagements. The PES schemes faced several challenges related to high population, smallholder farms, inadequate policy and legal frameworks and governance issues that tended to increase implementation costs and hinder effective participation. The opportunities include a wide range of conservation land uses such as contour terraces, tree planting, grass strips along rivers and differed or controlled grazing in drylands. PES schemes in most cases have provided significant benefits and income opportunities to local communities including increased agricultural incomes, social assets, employment and biodiversity conservation. The experience from pilot PES schemes provides practical lessons that can inform the future design and implementation of PES models within the context of the local situations. The agencies that have interest in forestry and other environment services should continue to pursue the path of PES mechanisms to address environmental degradation and diminishing environmental resources. This is premised on the fact that ES services directly and indirectly support socioeconomic development especially at local levels. However, there is need for some policy and legislative reforms to mainstream PES principles sectoral plans and conservation projects and was enhance enforcement of existing legislation and Acts Keywords: payment for ecosystem services, experiences status, watersheds, income opportunities
Role of cell wall on tomato fruit susceptibility to calcium deficiency disorder
The objectives of this study were to evaluate the effect of Ca2+ binding to the cell wall 14 on fruit susceptibility to BER
NMA CO (J=1-0) Observations of the Halpha/Radio Lobe Galaxy NGC 3079: Gas Dynamics in a Weak Bar Potential and Central Massive Core
within 24 lines with 80 characters) We present ^12CO (1-0) observations in
the central 4.5 kpc (1 arcmin) of the Halpha/Radio lobe galaxy NGC 3079 with
the Nobeyama Millimeter Array. The molecular gas shows four components: a main
disk, spiral arms, a nuclear disk, and a nuclear core. The main disk extends
beyond our spatial coverage. The spiral arms are superimposed on the main disk.
The nuclear disk with about 600 pc radius has an intense concentration of
molecular gas. Its appearance on PV diagrams is indicative of oval motions of
the gas, rather than circular. The nuclear core is more compact than our
resolution. Though it is unresolved, the nuclear core shows a very high
velocity about 200 km/s even at the radius of about 100 pc on the PV diagram.
We propose a model that NGC 3079 contains a weak bar. This model explains the
observed features: the main disk and spiral arms result from gaseous x1-orbits
and associated crowding respectively. The nuclear disk arises from gaseous
x2-orbits. From the appearance of the spiral arms on the PV diagram, the
pattern speed of the bar is estimated to be 55+-10 km/s/kpc. The high velocity
of the nuclear core cannot be explained by our model for a bar. Thus we
attribute it to a central massive core with a dynamical mass of 10^9 Msun
within the central 100 pc. This mass is three orders of magnitude more massive
than that of a central black hole in this galaxy.Comment: 43 pages, 17 figures; ApJ, 573, 105, 200
Paying for Happiness: Experimental Results from a Large Cash Transfer Program in Malawi
This study analyzes the short-term impact of an exogenous, positive income shock on caregivers’ subjective well-being (SWB) in Malawi using panel data from 3,365 households targeted to receive Malawi’s Social Cash Transfer Program that provides unconditional cash to ultra-poor, labor-constrained households. The study consists of a cluster-randomized, longitudinal design. After the baseline survey, half of these village clusters were randomly selected to receive the transfer and a follow-up was conducted 17 months later. We find that the short-term impact of household income increases from the cash transfer leads to substantial SWB gains among caregivers. After a year’s worth of transfers, caregivers in beneficiary households have higher life satisfaction and are more likely to believe in a better future. We examine whether program impacts on consumption, food security, resilience, and hopefulness could explain the increase in SWB but do not find that any of these mechanisms individually mediate our results
- …