832 research outputs found

    Supersymmetric FRW model and the ground state of supergravity

    Get PDF
    In this work we construct the vacuum configuration of supergravity interacting with homogeneous complex scalar matter fields. The corresponding configuration is of the FRW model invariant under the n=2n=2 local conformal time supersymmetry, which is a subgroup of the four dimensional space-time supersymmetry. We show, that the potential of the scalar matter fields is a function of the K\"ahler potential and of the arbitrary parameter α\alpha. This parameter enumerates the vacuum states. The scalar matter potential induces the spontaneous breaking of supersymmetry in supergravity. On the quantum level our model is a specific supersymmetric quantum mechanics, which admits quantum states in supergravity, and the states with zero energy are described by the wave function of the FRW universe.Comment: 18 pages, Revtex, submitted to PR

    NIKEL_AMC: Readout electronics for the NIKA2 experiment

    Full text link
    The New Iram Kid Arrays-2 (NIKA2) instrument has recently been installed at the IRAM 30 m telescope. NIKA2 is a state-of-art instrument dedicated to mm-wave astronomy using microwave kinetic inductance detectors (KID) as sensors. The three arrays installed in the camera, two at 1.25 mm and one at 2.05 mm, feature a total of 3300 KIDs. To instrument these large array of detectors, a specifically designed electronics, composed of 20 readout boards and hosted in three microTCA crates, has been developed. The implemented solution and the achieved performances are presented in this paper. We find that multiplexing factors of up to 400 detectors per board can be achieved with homogeneous performance across boards in real observing conditions, and a factor of more than 3 decrease in volume with respect to previous generations.Comment: 21 pages; 16 figure

    Steroidal Saponins from Furcraea hexapetala Leaves and Their Phytotoxic Activity

    Get PDF
    Four new steroidal saponins (1−4) along with 13 known saponins were isolated from the leaves of Furcraea hexapetala. The new compounds were identified as (20R,22R,25R)-3β-hydroxy-5α-spirostan-12-one 3-O-{α-Lrhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→3)-O-[β-D-glucopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)]-O-β-D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside} (1), (25R)-3β-hydroxy-5α-spirost-20(21)-en-12-one 3-O-{α-Lrhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→3)-O-[β-D-glucopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)]-O-β-D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside} (2), (25R)-5α-spirostan-3β-ol 3-O-{β-D-glucopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside} (3), and (25R)-5β-spirostan-3β-ol 3-O-{β-D-glucopyranosyl-(1→6)-O-β-D-galactopyranoside} (4) by spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry, and chemical methods. The phytotoxicity of the isolated compounds against the standard target species Lactuca sativa was evaluated. Structure−activity relationships for these compounds with respect to phytotoxic effects are discussed

    Effect of ionic strength on rheological behavior of polymer-like cetyltrimethylammonium tosylate micellar solutions

    Get PDF
    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The influence of ionic strength on the rheological properties of polymer-like aqueous micellar solutions of cetyltrimethylammonium tosylate (CTAT) containing different salts (KCl, KBr, (COONa)2, K2SO4 or K3PO4) is investigated. The rheological behavior of the solutions is analyzed above the concentration where a micellar entanglement network is formed, varying surfactant and salt concentration, salt counterion valency and temperature. A master curve of the linear viscoelastic properties is obtained by multiple superposition of time, temperature, salt type, and surfactant and salt concentration. Application of the existent kinetic theory provides information suggesting that the micellar solutions are in the fast breaking regime (i.e., the relaxation is kinetically controlled) regardless of salt type and concentration. Moreover, these solutions exhibit shear-banding flow with a reduced stress plateau (σ/G0, being σ and G0 the shear stress and the plateau modulus, respectively) that increases with salt content and counterion valency. The zero-shear viscosity (η0) and the main relaxation time (τC) diminish with increasing salt content according to a step-like function, in which the number of steps increases with the salt counterion valence. In contrast, G0 only increases slightly with increasing salt content for the five salts employed. These results are discussed in terms of ionic strength and screening of the electrostatic-interactions caused by the addition of salt. In addition, it was found that the influence of anions on the viscoelastic properties of the polymer-like micelles follows the Hofmeister series commonly encountered in macromolecular and biological systems. This finding opens a challenge for scientists in the experimental and theoretical fields

    Bioactive steroidal saponins from Agave offoyana flowers

    Get PDF
    Bioguided studies of flowers of Agave offoyana allowed the isolation of five steroidal saponins never described previously, Magueyosides A–E (1–5), along with six known steroidal saponins (6–11). The structures of compounds were determined as (25R)-spirost-5-en-2a,3b-diol-12-one 3-O-{b-D-xylopyranosyl-(1-3)-O-b-D-glucopyranosyl-(1-2)-O-[b-D-xylopyranosyl-(1-3)]-O-b-D-glucopyranosyl-( 1-4)-O-b-D-galactopyranoside} (1), (25R)-spirost-5-en-2a,3b-diol-12-one 3-O-{b-D-glucopyranosyl-(1-2)-O-[b-D-xylopyranosyl-(1-3)]-O-b-D-glucopyranosyl-(1-4)-O-b-D galactopyranoside} (2), (25R)-spirost-5-en-2a,3b,12b-triol 3-O-{b-D-glucopyranosyl-(1-2)-O-[b-D-xylopyranosyl-(1-3)]- O-b-D-glucopyranosyl-(1-4)-O-b-D-galactopyranoside} (3), (25R)-5a-spirostan-2a,3b-diol-12-one 3-O-{b-D-xylopyranosyl-(1-3)-O-b-D-glucopyranosyl-(1-2)-O-[b-D-xylopyranosyl-(1-3)]-O-b-D-glucopyranosyl-(1-4)-O-b-D-galactopyranoside} (4), and (25R)-5a-spirostan-2a,3b-diol-9(11)-en-12-one 3-O-{b-D-xylopyranosyl-(1-3)-O-b-D-glucopyranosyl-(1-2)-O-[b-D-xylopyranosyl-(1-3)]-O-b-D-glucopyranosyl-( 1-4)-O-b-D-galactopyranoside} (5), by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The bioactivities of the isolated compounds on the standard target species Lactuca sativa were evaluated. A dosedependent phytotoxicity and low dose stimulation were observed

    Phytotoxic steroidal saponins from Agave offoyana leaves

    Get PDF
    A bioassay-guided fractionation of Agave offoyana leaves led to the isolation of five steroidal saponins (1–5) along with six known saponins (6–11). The compounds were identified as (25R)-spirost-5-en-2α,3β-diol-12-one 3-O-{α-L-rhamnopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1→3)]-O-β-D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside} (1), (25R)-spirost-5-en-3β-ol-12-one 3-O-{α-L-rhamnopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1→3)]-O-β-D-glu copyranosyl-(1→4)-O-β-D-galactopyranoside} (2), (25R)-spirost-5-en-3β-ol-12-one 3-O-{β-D-xylopyrano syl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1→3)]-O-β-D-glucopyranosyl-(1→4)-O-β -D-galactopyranoside} (3), (25R)-26-O-β-D-glucopyranosylfurost-5-en-3β,22α,26-triol-12-one 3-O- {α-L-rhamnopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1→3)]-O-β-D-glucopyrano syl-(1→4)-O-β-D-galactopyranoside} (4) and (25R)-26-O-β-D-glucopyranosylfurost-5-en-3β,22α,26-triol- 12-one 3-O-{β-D-xylopyranosyl-(1→3)-O-β-D-glucopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1→3)]-O-β- D-glucopyranosyl-(1→4)-O-β-D-galactopyranoside} (5) by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The phytotoxicity of the isolated compounds on the standard target species Lactuca sativa was evaluated

    Operation Allelopathy: An Experiment Investigating an Alternative to Synthetic Agrochemicals

    Get PDF
    Synthetic herbicides represent a serious problem in modern agriculture because they are not biodegradable and can accumulate in the soil and in the groundwater, a situation that allows them to enter the trophic chain and ultimately leads to human exposure. Allelopathic chemicals offer an effective alternative to the synthetic compounds. The aim of this experiment is to highlight the differences between chemical and biological control of diseases in crops and to demonstrate the use of natural fungicides and herbicides as alternatives to synthetic chemicals. The experiment involves an evaluation by students of the potential of plant extracts as an alternative to synthetic agrochemicals to identify new ecological farming techniques that could be applied in agriculture. In an effort to encourage 1800 students in high school (14 to 16 years old) to have an interest in science, technology, and innovation, the third edition of the Summer Science Campus was organized by the Spanish Foundation for Science and Technology and the Ministry of Education, Culture, and Sports with support from the foundation Obra Social “la Caixa”

    Discovery of pyrazolopyrimidines that selectively inhibit CSF-1R kinase by iterative design, synthesis and screening against glioblastoma cells

    Get PDF
    We are grateful to Medical Research Scotland (PHD-1046-2016) for funding and a joint Cancer Research UK (A28596) and The Brain Tumour Charity award (GN-000676) to N. O. C. T. V. thanks EU Horizon 2020 research and innovation programme under the Marie Skls PHD-1046-2016Medical Research Scotland A28596Cancer Research UK GN-000676Brain Tumour Charity award 749299European Union (EU)MS

    Synthesis of (±)-3,4-dimethoxybenzyl- 4-methyloctanoate as a novel internal standard for capsinoid determination by HPLC-ESI-MS/MS(QTOF)

    Get PDF
    Capsinoids exhibit health-promoting properties and are therefore compounds of interest for medical and food sciences. They are minor compounds present in relatively high concentrations in only a few number of pepper cultivars. It is desirable to quantify capsinoids to provide selected cultivars with high capsinoid contents, which can then be employed as health food product. Quantifying low concentrations of capsinoids from pepper fruit requires a precise and selective analytical technique such as HPLC coupled to electrospray ionization - mass spectrometry, with development of an internal standard essential. In this work, the synthesis method of a novel compound analogue of capsinoids, the (±)-3,4-dimethoxybenzyl-4-methyloctanoate, which could be a suitable internal standard for capsinoid determination by electrospray ionization - mass spectrometry is described. (±)-3,4-dimethoxybenzyl-4-methyloctanoate was stable under the analysis conditions and exerted chemical and physical properties similar to those of capsinoids. This internal standard will provide an accurate capsinoid determination by electrospray ionization - mass spectrometry, thus facilitating the pepper breeding programs, screening pepper cultivars and a better understanding of capsinoid biosynthetic pathway

    IRAS4A1: Multi-wavelength continuum analysis of a very flared Class 0 disk

    Full text link
    Understanding the formation of substructures in protoplanetary disks is vital for gaining insights into dust growth and the process of planet formation. Studying these substructures in highly embedded Class 0 objects using the Atacama Large Millimeter/submillimeter Array (ALMA), however, poses significant challenges. Nonetheless, it is imperative to do so to unravel the mechanisms and timing behind the formation of these substructures. In this study, we present high-resolution ALMA data at Bands 6 and 4 of the NGC1333 IRAS4A Class 0 protobinary system. This system consists of two components, A1 and A2, separated by 1.8" and located in the Perseus molecular cloud at \sim293 pc distance. To gain a comprehensive understanding of the dust properties and formation of substructures in the early stages, we conducted a multi-wavelength analysis of IRAS4A1. Additionally, we sought to address whether the lack of observed substructures in very young disks, could be attributed to factors such as high degrees of disk flaring and large scale heights. To explore this phenomenon, we employed radiative transfer models using RADMC-3D. Our multi-wavelength analysis of A1 discovered characteristics such as high dust surface density, substantial dust mass within the disk, and elevated dust temperatures. These findings suggest the presence of large dust grains compared to the ones in the interstellar medium (ISM), greater than 100 microns in size within the region. Furthermore, while there's no direct detection of any substructure, our models indicate that some, such as a small gap, must be present. In summary, this result implies that disk substructures may be masked or obscured by a large scale height in combination with a high degree of flaring in Class 0 disks. [Abridged]Comment: Accepted for publication in A&A, 13 pages, 7 figure
    corecore