243 research outputs found

    Ground State Bands of the E(5) and X(5) Critical Symmetries Obtained from Davidson Potentials through a Variational Procedure

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    Davidson potentials of the form β2+β04/β2\beta^2 +\beta_0^4/\beta^2, when used in the original Bohr Hamiltonian for γ\gamma-independent potentials bridge the U(5) and O(6) symmetries. Using a variational procedure, we determine for each value of angular momentum LL the value of β0\beta_0 at which the derivative of the energy ratio RL=E(L)/E(2)R_L=E(L)/E(2) with respect to β0\beta_0 has a sharp maximum, the collection of RLR_L values at these points forming a band which practically coincides with the ground state band of the E(5) model, corresponding to the critical point in the shape phase transition from U(5) to O(6). The same potentials, when used in the Bohr Hamiltonian after separating variables as in the X(5) model, bridge the U(5) and SU(3) symmetries, the same variational procedure leading to a band which practically coincides with the ground state band of the X(5) model, corresponding to the critical point of the U(5) to SU(3) shape phase transition. A new derivation of the Holmberg-Lipas formula for nuclear energy spectra is obtained as a by-product.Comment: LaTeX, 12 pages, 4 postscript figure

    Influence of environmental factors on tenuazonic acid production by Epicoccum sorghinum: An integrative approach of field and laboratory conditions

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    Sorghum is the fifth most cultivated and consumed grain in the world. However, this grain is frequently contaminated with toxins from fungi. The present study evaluated the effects of environmental factors on tenuazonic acid (TeA) production by Epicoccum sorghinum in the field and in controlled laboratory conditions. In this study, 50 sorghum grain samples were collected from summer and autumn growing seasons and analyzed for TeA contamination using LC-MS/MS. To further understand the ecophysiology of this fungus, an isolated strain of E. sorghinum from the field was investigated for its development and TeA production under controlled environmental conditions in the laboratory. In the ecophysiological investigation, the effects of water activity (0.90, 0.95, 0.99) and temperature (18, 22, 26 and 30?°C) were evaluated on the radial growth, enzymatic production and expression of TAS1, which is the gene involved in TeA production. Results showed that in the field, the summer season presented the highest TeA average level in the grains (587.8??g/kg) compared to level found in the autumn (440.5??g/kg). The ecophysiological investigation confirmed that E. sorghinum produces more actively TeA under environmental conditions simulating the summer season. Optimum growth, maximum TAS1 gene expression, and higher extracellular enzymatic production were observed at 26?°C with a water activity of 0.99. Pearson correlation analyses showed that the production of TeA highly correlates with fungal growth. The present study demonstrates that abiotic factors in a combined approach of field and laboratory conditions will assist in predicting the driving environmental factors that could affect growth of E. sorghinum and TeA production in sorghum grains

    The first 62 AGN observed with SDSS-IV MaNGA -- III: stellar and gas kinematics

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    We investigate the effects of Active Galactic Nuclei (AGN) on the gas kinematics of their host galaxies, using MaNGA data for a sample of 62 AGN hosts and 109 control galaxies (inactive galaxies). We compare orientation of the line of nodes (kinematic Position Angle - PA) measured from the gas and stellar velocity fields for the two samples. We found that AGN hosts and control galaxies display similar kinematic PA offsets between gas and stars. However, we note that AGN have larger fractional velocity dispersion σ\sigma differences between gas and stars [σfrac=(σgas−σstars)/σstars\sigma_{frac}=(\sigma_{\rm gas}-\sigma_{stars})/\sigma_{\rm stars}] when compared to their controls, as obtained from the velocity dispersion values of the central (nuclear) pixel (2.5" diameter). The AGN have a median value of σfrac\sigma_{\rm frac} of AGN=0.04_{\rm AGN}=0.04, while the the median value for the control galaxies is CTR=−0.23_{\rm CTR}=-0.23. 75% of the AGN show σfrac>−0.13\sigma_{frac}>-0.13, while 75% of the normal galaxies show σfrac<−0.04\sigma_{\rm frac}<-0.04, thus we suggest that the parameter σfrac\sigma_{\rm frac} can be used as an indicative of AGN activity. We find a correlation between the [OIII]λ\lambda5007 luminosity and σfrac\sigma_{frac} for our sample. Our main conclusion is that the AGN already observed with MaNGA are not powerful enough to produce important outflows at galactic scales, but at 1-2 kpc scales, AGN feedback signatures are always present on their host galaxies.Comment: 19 pages, 8 figures, published in MNRA

    Filariasis of the Axilla in a Patient Returning from Travel Abroad: A Case Report

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    Background: The term filariasis comprises a group of parasitic infections caused by helminths belonging to different genera in the superfamily Filaroidea. The human parasites occur mainly in tropical and subtropical regions, but filariae are also found in temperate climates, where they can infect wild and domestic animals. Humans are rarely infected by these zoonotic parasites. Patients and Methods: A 55-year-old patient presented with a new-onset, subcutaneous, non-tender palpable mass in the right axilla. Ultrasonography showed a 1.3-cm, solid, singular encapsulated node. Sonography of the breast on both sides, axilla and lymphatic drainage on the left side, lymphatic drainage on the right side, and mammography on both sides were without pathological findings. The node was excised under local anesthesia as the patient refused minimal invasive biopsy. Results: On histopathological examination, the tail of a parasite of the group of filariae was found. The patient revealed that she had stayed in Africa and Malaysia for professional reasons. 6 months before the time of diagnosis, she had also suffered from a fever and poor general condition after a trip abroad. The patient was referred for further treatment to the Institute for Tropical Medicine at the University of Dusseldorf, where a treatment with ivermectin was conducted on the basis of positive staining with antibodies against filariae. Conclusion: Our case demonstrates the importance of interdisciplinary collaboration between breast center, pathology, and other specialties such as microbiology and tropical medicine

    Artificial neural network based modelling and optimization of refined palm oil process

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    YesThe content and concentration of beta-carotene, tocopherol and free fatty acid is one of the important parameters that affect the quality of edible oil. In simulation based studies for refined palm oil process, three variables are usually used as input parameters which are feed flow rate (F), column temperature (T) and pressure (P). These parameters influence the output concentration of beta-carotene, tocopherol and free fatty acid. In this work, we develop 2 different ANN models; the first ANN model based on 3 inputs (F, T, P) and the second model based on 2 inputs (T and P). Artificial neural network (ANN) models are set up to describe the simulation. Feed forward back propagation neural networks are designed using different architecture in MATLAB toolbox. The effects of numbers for neurons and layers are examined. The correlation coefficient for this study is greater than 0.99; it is in good agreement during training and testing the models. Moreover, it is found that ANN can model the process accurately, and is able to predict the model outputs very close to those predicted by ASPEN HYSYS simulator for refined palm oil process. Optimization of the refined palm oil process is performed using ANN based model to maximize the concentration of beta-carotene and tocopherol at residue and free fatty acid at distillate

    Microstructure and magneto-dielectric properties of the chitosan/gelatin-YIG biocomposites

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    This work is devoted to the preparation of yttrium iron garnet (YIG) ferrimagnetic biocomposites based in biodegradable chitosan and gelatin. The aim was to produce composite films containing controlled amounts of YIG to obtain a new biological material with magneto-dielectric features. Structural characterization of the biocomposites was made by scanning electron microscopy, X-ray diffraction, infrared absorption spectroscopy and thermal analysis, while the dielectric and magnetic properties were obtained from dielectric spectroscopy and magnetic hysteresis loops, respectively. The versatility of the films obtained makes them possible candidates for use as biomaterials or electronic device

    SSDSS IV MaNGA - Properties of AGN host galaxies

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    We present here the characterization of the main properties of a sample of 98 AGN host galaxies, both type-II and type-I, in comparison with those of about 2700 non-active galaxies observed by the MaNGA survey. We found that AGN hosts are morphologically early-type or early-spirals. For a given morphology AGN hosts are, in average, more massive, more compact, more central peaked and rather pressurethan rotational-supported systems. We confirm previous results indicating that AGN hosts are located in the intermediate/transition region between star-forming and non-star-forming galaxies (i.e., the so-called green valley), both in the ColorMagnitude and the star formation main sequence diagrams. Taking into account their relative distribution in terms of the stellar metallicity and oxygen gas abundance and a rough estimation of their molecular gas content, we consider that these galaxies are in the process of halting/quenching the star formation, in an actual transition between both groups. The analysis of the radial distributions of the starformation rate, specific star-formation rate, and molecular gas density shows that the quenching happens from inside-out involving both a decrease of the efficiency of the star formation and a deficit of molecular gas. All the intermediate data-products used to derive the results of our analysis are distributed in a database including the spatial distribution and average properties of the stellar populations and ionized gas, published as a Sloan Digital Sky Survey Value Added Catalog being part of the 14th Data Release: http://www.sdss.org/dr14/manga/manga-data/manga-pipe3d-value-added-catalog/Comment: 48 pages, 14 figures, in press in RMxA

    Gas phase metallicity determinations in nearby AGNs with SDSS-IV MaNGA: evidence of metal poor accretion

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    We derive the metallicity (traced by the O/H abundance) of the Narrow Line Region ( NLR) of 108 Seyfert galaxies as well as radial metallicity gradients along their galaxy disks and of these of a matched control sample of no active galaxies. In view of that, observational data from the SDSS-IV MaNGA survey and strong emission-line calibrations taken from the literature were considered. The metallicity obtained for the NLRs %each Active Galactic Nucleus (AGN) was compared to the value derived from the extrapolation of the radial oxygen abundance gradient, obtained from \ion{H}{ii} region estimates along the galaxy disk, to the central part of the host galaxies. We find that, for most of the objects (∼80 %\sim 80\,\%), the NLR metallicity is lower than the extrapolated value, with the average difference ()betweentheseestimatesrangingfrom0.16to0.30dex.Wesuggestthat) between these estimates ranging from 0.16 to 0.30 dex. We suggest that is due to the accretion of metal-poor gas to the AGN that feeds the nuclear supermassive black hole (SMBH), which is drawn from a reservoir molecular and/or neutral hydrogen around the SMBH. Additionally, we look for correlations between DD and the electron density (NeN_{\rm e}), [\ion{O}{iii}]λ\lambda5007 and Hα\alpha luminosities, extinction coefficient (AV)A_{V}) of the NLRs, as well as the stellar mass (M∗M_{*}) of the host galaxies. Evidences of an inverse correlation between the DD and the parameters NeN_{\rm e}, M∗M_{*} and AvA_{\rm v} were found

    Gas-phase metallicity determinations in nearby AGNs with SDSS-IV MaNGA : evidence of metal-poor accretion

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    We derive the metallicity (traced by the O/H abundance) of the narrow-line region (NLR) of 108 Seyfert galaxies as well as radial metallicity gradients along their galaxy discs and of these of a matched control sample of no active galaxies. In view of that, observational data from the SDSS-IV MaNGA survey and strong emission-line calibrations taken from the literature were considered. The metallicity obtained for the NLRs was compared to the value derived from the extrapolation of the radial oxygen abundance gradient, obtained from H II region estimates along the galaxy disc, to the central part of the host galaxies. We find that, for most of the objects (∼ 80 per cent), the NLR metallicity is lower than the extrapolated value, with the average difference ( D ) between these estimates ranging from 0.16 to 0.30 dex. We suggest that D is due to the accretion of metal-poor gas to the AGN that feeds the nuclear supermassive black hole (SMBH), which is drawn from a reservoir molecular and/or neutral hydrogen around the SMBH. Additionally, we look for correlations between D and the electron density (Ne), [O III]λ5007, and H α luminosities, extinction coefficient (AV) of the NLRs, as well as the stellar mass (M∗) of the host galaxies. Evidence of an inverse correlation between the D and the parameters Ne, M∗, and Av was found

    Câmeras modificadas e multiespectrais embarcadas em drones: enfoque para estudos da vegetação.

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    Nos últimos dez anos, os drones vêm sendo cada vez mais utilizados para aplicações florestais devido à sua flexibilidade, autonomia e capacidade de obter dados, de maneira remota, por meio de sensores embarcados. Essa ferramenta pode ser usada em substituição de algumas atividades de coleta de dados normalmente trabalhosas, demoradas, sujeitas a erro e de alto custo. Podem contribuindo, dessa maneira, para gerar informações decisivas para a gestão e a tomada de decisão na atividade florestal, com elevada precisão e custos reduzidos. Câmeras multiespectrais embarcadas em drones ampliam a capacidade de análise nos estudos de florestas plantadas e nativas, auxiliando na análise do desenvolvimento e da vitalidade dos plantios ou florestas e identificando fatores prejudiciais relacionados com estresses bióticos e abióticos. Entretanto, apesar dos avanços tecnológicos atingidos até o momento, a captura de dados de qualidade ainda permanece um grande desafio. Nesta publicação são apresentadas diretrizes orientadoras para o desenvolvimento de trabalhos sobre vegetação que envolvem a coleta de imagens por meio de câmeras multiespectrais, e modificadas, embarcadas em drones
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